U.S. patent application number 13/266074 was filed with the patent office on 2012-07-19 for battery module.
Invention is credited to Bjorn Eberleh, Felix Von Borck.
Application Number | 20120183823 13/266074 |
Document ID | / |
Family ID | 42289360 |
Filed Date | 2012-07-19 |
United States Patent
Application |
20120183823 |
Kind Code |
A1 |
Von Borck; Felix ; et
al. |
July 19, 2012 |
BATTERY MODULE
Abstract
The invention relates to a battery module which consists of a
plurality of interconnected cells that have respective positive and
negative terminals. The module is characterized in that the flat
terminals have cut-out sections and are arranged in two rows in
such a manner that the short ends of adjacent flat terminals of a
respective row face each other, in that the terminals of every row
are maintained at a distance to each other by specifically
arranged, conductive spacer elements and optionally insulating
spacer elements, in that within the module, the cells are
electrically connected in series and/or in parallel by specifically
arranging their positive and negative terminals in the one or the
other row, and in that the terminals of every row and the
interposed spacer elements are pressed against each other by a
bracing device.
Inventors: |
Von Borck; Felix;
(Barmstadt, DE) ; Eberleh; Bjorn;
(Alsbach-Hahnlein, DE) |
Family ID: |
42289360 |
Appl. No.: |
13/266074 |
Filed: |
April 23, 2010 |
PCT Filed: |
April 23, 2010 |
PCT NO: |
PCT/EP10/02524 |
371 Date: |
April 10, 2012 |
Current U.S.
Class: |
429/81 ; 429/120;
429/158; 429/90 |
Current CPC
Class: |
H01M 10/625 20150401;
H01M 50/20 20210101; Y02T 10/70 20130101; H01M 10/486 20130101;
H01M 10/441 20130101; H01M 10/663 20150401; H01M 10/443 20130101;
Y02E 60/10 20130101; H01M 10/052 20130101; H01M 10/613 20150401;
H01M 10/653 20150401; H01M 10/6553 20150401; H01M 10/647 20150401;
H01M 50/209 20210101; H01M 10/482 20130101; H01M 10/6568
20150401 |
Class at
Publication: |
429/81 ; 429/158;
429/120; 429/90 |
International
Class: |
H01M 10/50 20060101
H01M010/50; H01M 2/30 20060101 H01M002/30; H01M 10/48 20060101
H01M010/48; H01M 2/14 20060101 H01M002/14 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 24, 2009 |
DE |
10 2009 018 787.1 |
Claims
1. A battery module comprising a plurality of cells connected to
one another which each have a positive and a negative terminal,
wherein the terminals which are of areal design and provided with
cutouts are arranged in at least two rows such that the broad sides
of adjacent areal terminals of a respective row confront one
another, wherein the terminals of each row are held at a spacing
from one another by systematically disposed conductive spacer
elements wherein within the module the cells are connected
electrically in at least one of series and parallel to one another
by systematic arrangement of their positive and negative terminals
in the one or other row and wherein the terminals of each row and
also the spacer elements arranged there between are pressed against
one another by a clamping device.
2. A battery module in accordance with claim 1, wherein the areal
terminals are formed by extensions of the electrodes of the cells
and are designed for active cooling of the cells by intentional
heat dissipation and are connectable to a cooling device capable of
leading away heat.
3. A battery module in accordance with claim 1, wherein the
clamping device is formed by at least one tubular clamping bolt
through which a cooling fluid can optionally flow and with which
the cell terminals of the row are heat-conductingly connected.
4. A battery module in accordance with claim 3, wherein the
clamping bolts are surrounded by an insulting sleeve or are
provided with an electrically insulating coating.
5. A battery module in accordance with claim 1, wherein the cells
have at least substantially the shape of a flat parallelepiped,
with the positive and negative areal terminals of each cell being
arranged in at least one plane arranged parallel to the broad sides
of the parallelepiped-shaped cell.
6. A battery module in accordance with claim 1, wherein the one
pole of the battery module is connected at a first end of the one
row and the other pole is connected to the second end of the same
row disposed opposite to the said first end and is connected via an
extension to the first end of the other row adjacent to the said
first end so that electrical connections can be effected to the two
poles at a common side of the battery module.
7. A battery module in accordance with claim 6, wherein a spacer
element of the other row is extended to the side of the other row
to hold the extension.
8. A battery module in accordance with claim 1, wherein the areal
terminals of the cells have cutouts shaped to receive clamping
bolts forming the clamping device.
9. A battery module in accordance with claim 1, wherein a cooling
module is provided which has cooling plates at first and second
mutually oppositely disposed sides of the battery module and also
heat conducting connection plates extending between these sides
which form compartments between them accommodating the cells.
10. A battery module in accordance with claim 9, wherein two in
particular areal parallelepiped-shaped cells are arranged in each
compartment, wherein in each case one cell can be arranged at the
outer side of each of the outer connection plates, whereby each
cell is arranged at least one side adjacent to a heat dissipating
connection plate, i.e. each connection plate is arranged between
two cells.
11. A battery module in accordance with claim 9, wherein the
cooling plates arranged at the sides can be flowed through by a
coolant in one of a snake-like manner and in parallel through
corresponding passages of the plates and optionally through a
connection line between the cooling plates.
12. A battery module in accordance with claim 11, wherein the
snake-like passages each have an inlet and an outlet, with the
inlets and the outlets being provided on one side of the battery
module, on the same side as the pole terminals.
13. A battery module in accordance with claim 1, wherein it has a
two-part insulating housing through one part of which the pole
terminals and coolant connections are led out.
14. A battery module in accordance with claim 13, wherein the
housing has a pre-stressing means to press the adjacently disposed
cells against the heat-conducting connection plates arranged
adjacent to these cells.
15. A battery module in accordance with claim 13, wherein the
housing furthermore has a connection point for a battery management
system at the same side of the housing as the pole terminals and
the coolant connections.
16. A battery module in accordance with claim 1, wherein an
electronic system for monitoring and adaptation of the electrical
and thermal cell parameters is attached to the side of the battery
module at which the clamping device is provided and wherein the
parameters are directly picked up at the spacer elements by
contacting.
17. A battery module in accordance with claim 9, wherein a further
cooling plate connects the two said laterally disposed cooling
plates and wherein a plurality of cooling passages are guided in
parallel from a common inlet at the one side of the battery module
via the further cooling plate to a common outlet at the oppositely
disposed side of the battery module.
18. A battery module in accordance with claim 17, wherein the
common inlet and the common outlet are arranged at the front side
of the battery module at least substantially in the same plane as
the front side of the battery module in which the positive and
negative terminals of the battery cells are arranged and wherein a
further cooling plate which is integrally formed with the two
cooling plates is arranged at the oppositely disposed sides of the
battery module at the rear side of the battery module.
19. A battery module in accordance with claim 1, wherein both the
conducting spacer elements and also the insulating spacer elements
consists of metal and the insulating spacer elements are provided
with an insulation at their surface regions contacting the
conductive parts.
20. A battery module in accordance with claim 19, wherein the
clamping bolts and the spacer elements consists of the same metal
or of metals with comparable thermal coefficients of expansion.
21. A battery module in accordance with claim 19, wherein the
spacer elements consists of aluminum.
22. A battery module in accordance with claim 21, wherein the
conductive spacer elements are provided with a conductive coating,
for example of nickel, and the insulating spacer elements are
provided with an insulating coating, for example an anodized layer
and/or an organic or inorganic insulating layer.
23. A battery module in accordance with claim 1 wherein the
terminals of each row are held at a spacing from one another by
systematically disposed conductive spacer elements and by
insulating spacer elements.
Description
[0001] The present invention relates to a battery module comprising
a plurality of cells connected to one another which each have a
positive and a negative terminal and in particular concerns
accumulators especially lithium ion cells which are used for
forming a traction battery or battery module for vehicles with an
electrical drive drain. Such battery modules can for example be
used in electrical vehicles, hybrid vehicles with combustion
engines or hybrid vehicles with fuel cells. Through the modular
construction of a battery module in accordance with the invention
it can also be used for other purposes, for example for stationary
applications or for small traction applications, such as for
example in a wheelchair.
[0002] The battery module in accordance with the invention is
preferably built up on the basis of lithium ion cells however any
other available rechargeable battery cell can in principle also be
used.
[0003] A battery module system, which can for example be built up
from a plurality of like battery modules, can for example be
designed to cover a power range with an energy content between 1
kWh and 400 kWh or more and can straightforwardly operate in a
voltage range between 12 and 800 V. A battery module can for
example be designed with twelve individual cells each having a cell
voltage of 3.6 V and a capacity of 40 Ah in order to built up a
battery module having a total energy content of 1.728 kWh which,
depending on the interconnection of the individual cells, has
output voltages in the range from 10.8 V to 43.2 V with capacity
extraction in the range between 160 Ah and 40 Ah. By way of example
with a 3s4p connection, i.e. with four respective cells connected
in parallel which are connected three times in series after one
another an output voltage of 10.8 V (3.times.3.6 V) can be
generated and a battery module of this kind then enables a capacity
extraction of up to 160 Ah. With the configuration of 12s 1p, i.e.
with twelve cells in series, an output voltage of 43.2 V can be
achieved (12.times.3.6 V) and a current extraction of 40 A for one
hour is possible. In general the notation: XsYp has to be
understood in such a way that X recites the number of cells in
series and Y the number of cells in parallel. Through the circuit
variants the possibility also exists of obtaining different module
voltages with the same module size and the same basic
construction.
[0004] In order to achieve higher voltages a corresponding number
of battery modules can be connected electrically in series, the
connection of the individual battery modules to one another can
also take place in accordance with the pattern XsYp.
[0005] A reference system for use in electrical battery compact
vehicles can for example be orientated on the following corner
point data: total energy content of modules 13.824 kWh (i.e. eight
battery modules each having 1.732 kWh), voltage level 400 V and
continuous power .+-.20 kW. In this connection it should be noted
that for the generation of a voltage level of 400 V it can be
necessary to step up the total output voltage of the battery with
the aid of an inverter and/or a transformer. For example when using
eight battery modules of the above-named kind in a 6s2p
configuration with 21.6 V output voltage per battery module, a
total output voltage with a series circuit of all eight battery
modules of 8.times.21.6 V=172,38 V is achieved.
[0006] Even though a battery module of this kind may be designed
for a continuous power of .+-.20 kW nevertheless peak powers of for
example 100 kW can be demanded in short term from the battery for
example for acceleration purposes, whereby excellent acceleration
values can be achieved.
[0007] In charging operation one can for example operate with a
charging power of 40 kW.
[0008] The above quoted values are simply named as an example, but
on the other hand represent values which can entirely be achieved
with commercially available lithium ion batteries.
[0009] Basically the technology of the battery design which appears
most suitable in accordance with the criteria of the technical
potential can be used at the cell level, such as for example energy
and power density, reliability and working life, cost potential and
resource availability. At the system level or module level the
reliability, the long working life and comfort in operation must
also be taken into account. Furthermore, the additional measures
which are required to achieve a functioning battery system should
involve a minimum of additional cost, weight and volume. Such
additional measures relate for example to the electrical management
of the battery module, to the thermal management of the battery
module, to the integration at the cell level and module level and
also to the integration into a vehicle.
[0010] The present invention is based on the object of making
available a battery module or battery module system consisting of a
plurality of like modules which is compactly designed and of
thermally optimized design, with the operating temperature of the
battery module or of the battery module system being able to be
held within tight limits in order to avoid as far as possible local
overheating of individual cells or elevated temperatures of one or
more cells.
[0011] Furthermore, starting from a basic construction and
depending on the specific required conditions of use, the design of
the respective battery modules should be variable and make possible
the attainment of a compact and easily connectable design of the
battery module or of the battery module system and also the
manufacture of such battery modules and battery module systems at a
favorable price.
[0012] In order to satisfy this object a battery module of the
initially named kind is provided in accordance with the invention
which is characterized in that the terminals which are of areal
design and provided with cutouts are arranged in at least two rows
such that the broad sides of adjacent areal terminals of a
respective row confront one another, that the terminals of each row
are held at a spacing from one another by systematically disposed
conductive spacer elements and, if necessary, by insulating spacer
elements, in that the cells are connected electrically in series
and/or parallel to one another within the module by systematic
arrangement of that positive and negative terminals in the one or
other row and in that the terminals of each row and also the spacer
elements arranged there between are pressed against one another by
a clamping device.
[0013] A mechanical layout of the battery module of this kind makes
it possible first of all, depending on the systematic arrangement
of the positive and negative terminals of the cells within the
module, to achieve different operating voltages and operating
currents with a basically similar design of the battery module, so
that most components can be used in the different variants and few
special parts required, if at all, which would otherwise increase
the manufacturing costs. It is also basically possible to select
the number of the cells per battery module flexibly and
nevertheless to use many common components in the manufacture of
the respective battery modules. The battery size can be scaled by
the modular concept and the electrical and hydraulic connection
possibilities in wide ranges. The design principles can be rapidly
and simply adapted with changed cell geometry or performance data
to other flat cells.
[0014] The battery module in accordance with the invention can thus
be flexibly designed and itself quasi has a modular
construction.
[0015] Through the use of areal terminals it is possible, on the
one hand, to make the individual cells, which are preferably of
parallelepiped shape in plan view, relatively flat, whereby heat
can be dissipated from the individual cells via the areal
terminals. Through the flat parallelepiped shape of the cells which
results through this heat can also be readily transferred away from
the flat sides of the cell, whereby a precondition can be provided
for attaining a tight temperature operating range in the cell.
Since the terminals of each row can be pressed against one another
by a respective clamping device or against spacer elements arranged
therebetween, it can be ensured that resistance losses at the
different terminals do not arise or only arise to a small degree
and that the battery module always has the desired output voltage
over the entire working life of the battery module corresponding to
the respective state of charge, because constant circumstances
prevail and changing ohmic losses are not to be expected.
[0016] It is particularly favorable when the areal terminals are
formed by extensions of the electrodes of the cells and are
designed for intentional heat dissipation from the cells for the
active cooling of the cells and are connected to a heat dissipating
cooling device. In this way the leading away of heat from the
interior of the cell is favored.
[0017] The clamping devices are preferably formed by at least one
clamping bolt, in particular by at least one preferably tubular
clamping bolt for each row.
[0018] When using tubular clamping bolts which are favorable for
weight saving reasons it would also be conceivable to cool these in
the interior with a liquid cooling medium for example a liquid
coolant in order to favor the dissipation of heat.
[0019] A tubular clamping bolt of this kind can be thermally
connected at at least one position to the conducting or
non-conducting spacer elements (and thus thermally to the cell
terminals) and/or directly to the cell terminals. Thus the clamping
device can also be used in order to intentionally dissipate heat
from the cells.
[0020] The clamping bolts are as a rule surrounding by an
insulating sleeve in order to avoid undesired short circuits.
[0021] It is particularly favorable when the cells have at least
substantially the shape of a flat parallelepiped, with the positive
and negative areal terminals of each cell preferably being arranged
in one plane or in respective planes which is or are arranged
parallel to the broad sides of the parallelepiped-shaped cells.
[0022] In this way not only is a compact arrangement favored but
rather, depending on the design of the battery module, each cell
can be built in either in one direction in which for example the
positive terminal lies at the left side of the cell and the
negative terminal at the right side of the cell or they can be
built in inverted so that a negative areal terminal lies at the
left side and the positive terminal at the right side. In this way
serial and/or parallel connections of the individual cells can be
selected depending on the direction of installation of the cells in
the battery module, with insulating elements having to be provided
depending on the selected configuration. With an arrangement of
this kind the arrangement can be so designed that spacer elements
having the same shape are always used, whereby the spacer elements
can be manufactured per se in cost-favorable manner and rationally
in large series.
[0023] In a practical embodiment it is favorable when the one pole
of the battery module is connected to a first end of the one row
and the other pole to the second end of the same row or also of the
other row opposite to the said first end. The pole at the second
end of the row is then led via an extension to the first end of the
other row adjacent to the said first end. In this way electrical
connections can be made to both poles at a common side of the
battery module, for example the pole terminals can then lie at the
top face of the battery, for example at the same side of the
battery where they are readily accessible.
[0024] With this design it is straightforwardly possible to extend
a spacer element of the said other row to the side of the other row
to hold the extension.
[0025] It is in particular favorable when a cooling module is
provided which has cooling plates at first and second oppositely
disposed sides of the battery module and is also provided with heat
conducting connection plates which extend between these sides and
form compartments receiving the cells between them.
[0026] As will be explained later in more detail then it is
possible with a compact manner of construction to effectively cool
the two cooling plates by means of a coolant liquid over at least
substantially their entire surface and it is hereby also possible
to extract heat from the heat conducting connection plates between
the two cooling plates, whereby the cells which are arranged
adjacent to the cooling plates are likewise intensively cooled.
[0027] It is particularly favorable In an embodiment of this kind
when an arrangement is used in which two especially areal cells in
the shape of a parallelepiped are arranged in each compartment with
a respective cell optionally being able to be arranged at the outer
side of the outer connection plates. In this way each cell is
arranged at at least one side adjacent to a heat conducting
connection plate, whereby heat can be favorably extracted from the
narrow flat cells via the corresponding broad side of the cell.
[0028] The cooling plates arranged at the side are preferably
designed so that a liquid coolant can flow through them, which is
preferably pumped through snake-like passages of the plates, if
necessary, through a connection line between the cooling plates. In
this manner the cooling plates can be cooled over their full area
whereby a favorable heat extraction from the connection plates can
likewise be achieved.
[0029] The snake-like passages each have an inlet and an outlet
with the inlets and the outlets preferably being provided at one
side of the battery module, in particular at the same side as the
poles. This signifies that when using a plurality of battery
modules in a battery module system not only the electrical
connection between the modules but also the coolant connections
between the modules can be made particularly favorably from one and
the same side. An arrangement of this kind also makes the design of
the module housing simpler in which the battery module is
installed.
[0030] The cooling plates are preferably each formed by at least
one base plate having channels and a cover plate, with the cover
plate being welded, solded or adhesively bonded to the base plate.
The plate with the channels can then be produced as a simple
pressed part while the cover plate formed by an at least
substantially non-deformed sheet metal part. This represents a
favorably priced possibility of manufacturing of such a cooling
plate. As an alternative the cooling plate can also be functionally
replaced by a snake-like/meandering looping tube.
[0031] With the battery module of the invention a respective
insulating, preferably two-part housing should in particular be
used with the poles and the optionally provided cooling connections
being led out of one of its parts.
[0032] The housing can have a clamping means, for example in the
form of a foam inlay at its two oppositely facing inner sides which
press the cells arranged at the opposite sides of the battery
module against the heat conducting connecting plates arranged
adjacent to these cells. Through this clamping the heat dissipation
from the cells arranged at the outside is favored. The cells which
are arranged pair-wise in the compartments beneath the cooling
module can either tightly contact the connecting plates forming the
respective compartments or can likewise be introduced with a foam
insert or with a heat-conducting paste or an adhesive bond between
the cells into a heat-conducting connection with the connecting
plates.
[0033] It is particularly favorable when the housing furthermore
has a connection point for a battery management system which is
preferably provided at the same side of the housing as the poles
and the coolant terminals. On installing the battery module in a
vehicle both the electrical connections to the poles and also the
coolant connections to the cooling module and also the connection
of the battery management system can then take place from one side
of the battery. In the case of the battery management system a
simple customary interface plug or bus plug can be used.
[0034] As mentioned above the battery modules in accordance with
the invention can be combined in the battery module system
consisting of a plurality of like battery modules, with this
preferably taking place in such a way that a plurality of parallel
cooling circuits, in particular seven to nine parallel cooling
circuits are provided which are fed via a distribution tube and
also connected to a connecting tube. It is particularly favorable
when in each case two to four and in particular two battery modules
are connected to one another in series, with the coolant passages
inside the battery modules preferably having a flow cross-section
corresponding to that of a pipe having an internal diameter of 8 to
9 mm.
[0035] With a liquid cooling of this kind the distribution tube and
the collection tube can communicate with a main line which has a
pump and a radiator, optionally with a fan. The heat can then be
extracted from the cooling system via the radiator and the
preferably used fan.
[0036] The main line or any supply container for the liquid coolant
from which the main line starts can furthermore have a heating
device which can be used to preheat the liquid coolant and
correspondingly the individual cells, for example when as a result
of the outside temperature the operating temperature of the battery
would otherwise be too low. In other words the existing cooling
system can be straightforwardly used in order to preheat the
battery modules, i.e. can also be used as a heating system.
[0037] The main line can furthermore contain a heat exchanger
(optionally an additional head exchanger) with at least one further
circuit which feeds a heating system or an air conditioning system.
In this way the heat which is extracted from the battery module
system can be used for air conditioning or heating of the passenger
compartment of the vehicle or can be cooled via this air
conditioning system.
[0038] The battery module system can be in combination with a valve
which can be controlled in such a way that the exhaust air from the
radiator is optionally at least partially deflected into the
interior space of the vehicle compartment for heating or outwardly
if the passenger compartment is in any event adequately heated.
[0039] The invention will be explained in more detail in the
following with reference to embodiments and to the drawing in which
are shown:
[0040] FIG. 1 a perspective representation of a cooling module in
accordance with the invention,
[0041] FIG. 2A a perspective representation of the front side of
the cooling module of FIG. 1 with inserted lithium ion cells and
also a front plate, i.e. the front side of the battery module in
accordance with the invention without a housing,
[0042] FIG. 2B a plan view of a cell which is used in the
embodiment of FIG. 2A,
[0043] FIG. 2C a side view of the cell of FIG. 2B corresponding to
the arrow IIC of FIG. 2B,
[0044] FIG. 3A a front view of the battery module of FIG. 2 with
the said front plate removed with only the terminals of the cell
being visible,
[0045] FIG. 3B a view from above on the representation of FIG.
3A,
[0046] FIG. 3C a perspective representation of a base plate of the
battery modules of FIGS. 2 and 3 with the clamping bolt being
shown,
[0047] FIG. 4 a representation of some possible electrical
configurations of a traction battery module in accordance with the
invention including the 6s2p configuration which is used in the
battery module of the invention in accordance with FIGS. 2 and
3,
[0048] FIG. 5 a second schematics representation of the connection
of the battery module of FIG. 3A corresponding to the 6s2p
configuration of FIG. 4,
[0049] FIG. 6 a further schematic illustration which makes it
easier to bring the circuit plan in accordance with FIG. 5 into
agreement with the representation of the battery module of the
invention in accordance with FIG. 3A,
[0050] FIGS. 7A-7E drawings which show the construction of the
cooling plate of FIG. 1 more precisely, with
[0051] FIG. 7A being a perspective representation of the cooling
plate of FIG. 1 with the inlet and outlet tubes not yet having been
attached,
[0052] FIG. 7B a section drawing of the pressed inner side of the
cooling plate of FIG. 7A at the section plane VIIB-VIIB of FIG.
7D,
[0053] FIG. C an enlarged representation of the encircled region of
the FIG. 7B,
[0054] FIG. 7D a plan view of the pressed inner plate of FIG. 7A
and
[0055] FIG. 7E a perspective representation of the pressed internal
side part of the cooling plate 18 of FIG. 7A to a smaller
scale,
[0056] FIG. 8A a perspective illustration from the front and from
above of the lower half of the housing for the battery module of
FIG. 2,
[0057] FIG. 8B a perspective illustration on the underside of the
housing half of FIG. 8A,
[0058] FIG. 8C a perspective representation from the front, from
the right and from above onto the upper half of the housing of the
battery module,
[0059] FIG. 8D a perspective illustration of the inner side of the
upper housing half of FIG. 8C but to a smaller scale,
[0060] FIG. 8E a perspective illustration from the front, from the
right and from above on the housing of the finished battery
module,
[0061] FIG. 9 a perspective illustration of an alternative
embodiment of the cooling plates of FIG. 7A through the use of one
or more meandering bent pipes instead of a sheet metal
construction,
[0062] FIGS. 10A-10C three drawings to explain the possible design
of the cooling in a battery module system in accordance with the
invention having eight individual battery modules,
[0063] FIG. 11A a cooling system in accordance with the invention
having in each case two battery modules in series,
[0064] FIG. 11B a cooling system in accordance with the invention
similar to FIG. 11A but having two separate cooling paths for each
battery module,
[0065] FIG. 11C a further design of a cooling system in accordance
with the invention having in each case four battery modules in
series,
[0066] FIG. 11D a drawing corresponding to FIG. 11B but
supplemented by four further modules,
[0067] FIG. 12A, 12B two tables for further explaining a cooling
system in accordance with the invention,
[0068] FIG. 13 a representation of a cooling system in accordance
with the invention having a pump and a radiator with a fan and
[0069] FIG. 14 a representation similar to FIG. 13 with a further
heat exchanger,
[0070] FIG. 15 a plan view similar to FIG. 2B but in an alternative
embodiment,
[0071] FIGS. 16A and 16B a perspective illustration and also a
sectional drawing of a conductive spacer element,
[0072] FIG. 16C and 16D a perspective illustration and also a
sectional drawing of an insulated spacer element and
[0073] FIG. 17 a perspective representation of a separating comb in
accordance with the invention for the individual cell terminals of
the cells of the battery module in front of a modified cooling
module in accordance with the invention.
[0074] Referring first of all to FIGS. 1 and 2 a cooling module 10
is shown in a perspective illustration which is used in the
following manner which will be explained in more detail for the
heat dissipation from the individual cells 12 of the battery module
14. The cooling module 10 has cooling plates at the first and
second oppositely disposed sides of the module and is furthermore
provided with heat conducting connection plates 20 in sheet metal
form which extend between these sides and which between them form
compartments 22 to receive the cells 12. The connection plates 20
have side parts 24 bent at a right angle which are adhesively
bonded over their full area to the cooling plates 16, 18 or welded
onto the latter or solded onto the latter in order to ensure a high
quality thermal transfer between the connector plates 20 and the
cooling plates 16, 18.
[0075] It has been found in accordance with the invention that a
connection plate of aluminum or an aluminum alloy having a
thickness of about 1 mm is fully sufficient in order to achieve an
adequate heat dissipation and an adequately uniform temperature of
the individual cells.
[0076] Each cooling plate 16 and 18 respectively has a respective
tubular inlet 26 and a tubular outlet 28 for a liquid coolant,
which--for example as shown in FIG. 9--can flow through a
snake-like coolant passage in each cooling plate 16, 18 from its
inlet 26 to its outlet 28. In this connection the tubular inlets
and outlets 26, 28 can for example be welded, soldered or
adhesively bonded at the suitable points to the cooling plates 16,
18 and communicate with the respective snake-like passage. The
tubular inlets and outlets 26, 28 are provided with a hose
connection gland 30 and 32 respectively so that flexible hoses can
be attached in liquid-tight manner to the hose connection
glands.
[0077] In connection line 34 not shown in FIG. 1 but in FIG. 9 can
connect the outlet of the left-hand cooling plate 18 (outlet in
FIG. 1 not visible) to the input 26 of the right-hand cooling plate
16. As can in particular be seen from FIG. 2A the individual cells
12 are preferably used pair-wise in compartments of the cooling
module and in addition one cell 12' is provided on the top side of
the upper connecting plate 20' in FIG. 1 and a further cell (not
visible) is arranged beneath the lowermost connecting plate 20'' in
FIG. 1. Since, in this example, five compartments 22 are formed by
means of six individual connection plates 20 which each accommodate
two cells and since two further cells are arranged on the outer
side of the outer connection plates 20', 20'' the battery module 14
of FIG. 2A includes twelve individual cells 12. Naturally the
number of the individual cells can be increased, for example to
fourteen or more, by using further connection plates 20 and the
corresponding formation of further compartments 22 accommodating
the cells 12. Nevertheless the use of twelve cells 12 for each
battery module 14 seems to be a particularly favorable design. In
front of the battery modules in FIG. 2A there is a circuit board
302 of the battery management system which controls the charging
and discharging of the battery cells in a manner known per se. The
circuit board 302 is connected to the module with screws 304 which
engage into the spacer elements 44 and 46 respectively.
[0078] The design of the cooling module can also be selected such
that only one cell 12 is accommodated in each compartment. To
increase the heat transfer from the cells to the connection plates
(and optionally vice versa) a heat conducting paste (conductive
paste), a defined contact pressure or an adhesive can be provided
between the cells and the connection plates.
[0079] Each cell 12 has in this example a positive and a negative
terminal 36 and 38 respectively with the positive and negative
terminals 36, 38 in particular being visible in the form of black
horizontal lines in FIGS. 2 and 3. They are arranged in two rows, a
left-hand row 40 and a right-hand row 42 and in this example both
rows are arranged at the same (front) side of the battery module
14. This is however not essential, the one row could for example be
arranged at the front side of the battery module and the row at the
rear side of the battery module. As can be seen particularly from
FIG. 3A the broad sides of adjacent areal terminals 36, 38 of a
respective row 40, 42 are arranged facing one another. From FIG. 3A
it can be seen that the terminals 36, 38 of each row 40, 42 are
held spaced from one another by intentionally arranged contacting
spacers 44 and insulating spacer 46. As can in particular also be
seen from FIGS. 5 and 6 and as will be explained somewhat later in
more detail the cells 12 are connected pair-wise electrically in
parallel to one another and the six so formed cell pairs are
connected thereto in series by intentional arrangement of their
positive and negative terminals 36, 38 in the one or other row 40,
42. In this connection the terminal arrangement of FIG. 3A can be
relatively easily recognized in FIG. 5 and one can then better see
the precise connection of the cells from FIG. 6 which can
relatively easily be brought into agreement with FIG. 5.
[0080] The arrangement of the cells shown in FIGS. 3A, 5 and 6
corresponds to the 6s2p variant of FIG. 4. The other variants of
FIG. 4, i.e. the 12s1p, 4s3p and 3s4p variants can be realized by
corresponding arrangement of the terminals 36 and 38 in the two
rows 40 and 42, with corresponding positioning of conducting and
insulating spacer elements 44, 46, and indeed using the same parts
as in the embodiment of FIG. 3A. Many degrees of freedom arise
through the flexible modular construction.
[0081] The terminals 36, 28 of each row and also the spacer
elements arranged therebetween are pressed against one another by a
clamping device 48.
[0082] The clamping device 48 for each row is formed by at least
one clamping bolt 50, preferably by two or three such clamping
bolts 50 (as shown in FIG. 3A). The heat conducting plate 52 (or
base plate) is conductingly bolted here at its two ends 54, 56 to
the respective right-hand and left-hand cooling plates 16, 18.
[0083] Each clamping bolt 50 is connected in this example by a
rivet connection 57 in the form of a beaded-over joint to the
heat-conducting base plate 52. Instead of this, an adhesive
connection, a soldered connection or a welded connection could be
used. The use of a plurality of clamping bolts or bolts per pole
makes it possible to increase the contact pressure and also ensures
an improved distribution of the force and of the redundancy. The
pole outlets 66, 70 are designed independently of the passage bores
for the clamping bolts 50. They can thus be led out flexibly as
required.
[0084] It is particularly favorable when the clamping bolts 50 are
made of aluminum to generate a heat-conducting connection. The
construction can be so selected that the clamping bolts are each
designed as an aluminum tube with a very thin coating which is
electrically insulating, mechanically very stable and thermally
conducting as well as possible (instead of providing a separate
insulating sleeve which is detrimental for the heat dissipation).
The use of the through going clamping bolts 50 minimizes the
installation cost and complexity. Furthermore, the possibility
exists for thermally connecting the clamping bolts 50 designed as
tubes with a through flowing liquid coolant for cooling the
terminals.
[0085] The insulation of the poles relative to the bolted
connection and the base plate can for example take place via
pertinax, ceramic or nomex paper.
[0086] The insulating spacer elements can furthermore consist of
pertinax or ceramic.
[0087] The preferred embodiment of the spacer elements be it
conductive elements or insulating elements will be explained later
in more detail with reference to FIGS. 16A to 16D.
[0088] The electrical insulation of the clamping bolts formed by
tubes can also take place through fiber materials or surface
treatment.
[0089] In order to avoid electrical short circuits, the clamping
bolts 50 are each surrounded by an insulating sleeve 58. At their
upper ends 60 shown in FIG. 3 the clamping bolts are each provided
with a thread onto which a respective nut 62 is screwed, with each
nut 62 being arranged above a washer 63. The clamping bolts can be
tightened in order to clamp the individual battery terminals 36, 38
to the spacer elements 44, 46 lying therebetween and hereby to
ensure that transition resistances between the individual cell
terminals 36, 38 and the conductive spacer elements 44 lying
therebetween are precluded or are at least minimized. The washers
63 can be formed by individual washers or have the form of an
elongate plate with two holes to receive the clamping bolts 50. As
is in particular evident from FIG. 2B the cells 12 have at least
essentially the shape of a flat parallelepiped with the positive
and negative areal terminals 36, 38 of each cell 12 being arranged
in one plane or in respective planes which is or are arranged
parallel to the broad sides of the parallelepiped cell.
[0090] In order to facilitate the introduction of the cells into
the battery module in accordance with FIG. 2A the terminals 36, 38
each have two U-shaped cutouts 37, 39--as is evident from FIG.
2B--which makes it possible to insert the cells 12 into the cooling
module 10 from the rear and to push them forwardly so that they
enter into the clamping region of the clamping bolts. It should
likewise be possible to previously insert the cells 12 into the
cooling module 10 from the front or from the rear and to introduce
the clamping bolts 50 and the spacer elements 44, 46 from the front
between the terminals 36, 38 so that the clamping bolts 50 enter
into the U-shaped cutouts.
[0091] The reference numeral 66 points to the positive pole of the
battery module 14 and is connected at a first end 68 of the
left-hand row 40 of the terminals whereas the other, negative pole
70 is connected to the second end 72 of the left-hand row disposed
opposite the said first end 68. The second pole 70 is guided via a
conducting plate 74 and an extension 76 to the said first end 78 of
the right-hand row adjacent to the first end 68 of the left-hand
row so that electrical connections to the two poles 60 and 70 can
be effected at a common side of the battery module 14. In this
example both the positive pole 66 and also the negative pole 70 or
the corresponding extension 76 are provided with a respective
internal thread 80 and 82 respectively. This makes it possible to
connect electrical connection lines (not shown) to the respective
battery module 14 or to connect the respective battery module 14 to
further like modules to form a battery module system. Furthermore,
the internal threads 80 and 82 provided within upwardly projecting
cylindrical collars (not shown) which on insertion of the battery
module into an (insulating) housing on the one hand ensures the
required electrical contact and, on the other hand, a seal against
water entry, for example via means of an O-ring placed on the
cylindrical collar which seals the housing, the cylindrical collar
and the lower side of the electrical terminal.
[0092] A spacer element 46 of the right-hand row is extended to the
side of the right-hand row 42 for the holding of the extension 76,
i.e. is provided with a corresponding extension 84.
[0093] At this point it should briefly be mentioned that the ends
of the connection plate 74 are likewise passed through by the
clamping bolts 50 of the left and right-hand rows 40, 42. However,
an insulating plate is inserted between the conductive connection
plate 74 and the lower positive cell terminal 36 of the right-hand
row because otherwise a short circuit will take place between the
right and left terminals of the lowest cell 12, which is naturally
not permissible. The upper ends 68 and 78 of the left and
right-hand rows 40, 42 are likewise connected together with an
insulating plate 79 through which the clamping bolts 50
correspondingly pass.
[0094] As indicated briefly above the cooling plates 16, 18 of the
cooling module 10 arranged at the side are flowed through in
operation by a liquid coolant, which preferably can be pumped in
snake-like manner through corresponding passages of the plates 16,
18 and optionally through a connection line 36 between the cooling
plates 16, 18.
[0095] The specific design of the cooling plates can be seen in
detail from the FIGS. 7A to 7E. As FIG. 7A shows the tubular inlet
of the cooling passage of the left-hand plate in this example is
guided from the top to the bottom and is attached there to a
lateral lug 86 of the cooling plate 16, which can for example take
place by a solded connection, a welded connection or an adhesively
bonded connection. The snake-like cooling passage leads then in the
example of FIG. 7A with a first vertical section 88 upwardly then
with a second horizontal section 90 to the right, than via a
further shorter vertical section 92 downwardly, via the fourth
horizontal section 94 to the left, via a fifth vertical section 96
downwardly at the left-hand side of the cooling plate, via a sixth
horizontal section 98 to the right, via a seventh vertical section
100 at the right-hand side of the cooling plate downwardly and via
an eighth horizontal section 102 of the cooling passage to the left
to a further vertical section 104, which subsequently leads via a
further horizontal section 106 to the right to a further lug 108 to
which the tubular outlet 28 is connected (here likewise with a
solded connection, a welded connection or an adhesively bonded
connection).
[0096] The passages 86, 88, 90, 92, 94, 96, 98, 100, 102, 104 and
106 themselves are generated, as can be seen from FIG. 7B by a
corresponding pressing of a sheet metal part or of a base plate 85
which leads to ribs 99 between the cooling passages 86, 88, 90, 92,
94, 96, 98, 100, 102, 104, 106, 108 and also at the top and at the
bottom of the sheet metal part to which a flat sheet metal cover
plate 110 can be attached, here also by means of a soldered
connection or a welded connection or an adhesively bonded
connection. The result, prior to the attachment of the connection
tubes 26, 28, can be seen in a perspective illustration (to a
smaller scale) from the FIG. 7E. The left-hand and right-hand
cooling plates 6, 18 are identically designed so that only three
different parts are required in order to form both cooling plates.
These are the ribbed sheet metal part of FIG. 7B, the sheet metal
cover part 110 and the turned tubular part which forms the inlet
and outlet tubes 26, 28. All parts consists of aluminum or of an
aluminum alloy.
[0097] Through the use of a tubular inlet 26 and a tubular outlet
28 the actual inlet and the actual outlet can in this way be
provided at the same side of the battery module and indeed
preferably at the same side as the pole connections 80 and 82, i.e.
at the upper side of the battery module 14 as one can see from the
specific embodiment of FIGS. 2A and 3A. It would, however, already
be possible to realize the inlet and outlet connections to the
snake-like cooling plate differently. For example, one can lead
both of the connection tubes 26, 28 out at the top side of the
cooling plate of FIG. 7A (instead of at the bottom side as shown in
FIG. 7A) or can arrange the inlet tube 26 or the outlet tube 28 at
the top and the respective other outlet 28 or inlet 26 at the
bottom. It should be brought out that it is not absolutely
essential to design the left-hand and right-hand plates 16, 18 of
the cooling module 10 as directly cooled plates in the sense that
liquid passages for a liquid coolant are present there, but rather
it would also be conceivable to provide a rear plate of the cooling
module and to correspondingly form this with cooling passages while
the left-hand and righthand plate 18, 16 of the cooling module 10
can be formed by simple sheet metal plates. The preferred
arrangement is however the embodiment in accordance with FIG. 1 or
FIGS. 7A to 7E and 9.
[0098] The geometry of the cooling passages in accordance with FIG.
7A can be changed so that flow takes place in parallel through the
channels. Thus, lower pressure loss arises and a plurality of
cooling plates or cooling modules can be connected in series. This
signifies that the tubular connection and discharge tubes 26, 28
must each be attached to a plurality of cooling passages of the
cooling plates which extend parallel to one another instead of to
the snake-like arrangements of FIGS. 7A to 7E.
[0099] The cooling module 10 in accordance with FIG. 1 with the
inserted cells 12 in accordance with FIGS. 2 and 3 is received in a
two-part insulating housing 111 of which details can be found in
FIGS. 8A to 8E. The FIG. 8A shows that a lower half 112 of the
housing 111 is at least substantially of parallelepiped shape, its
lower side 114 in accordance with FIG. 8B is provided with ribs 116
for stiffening. At the inner side of the lower half 2 of the
housing there is located a foam material inlay 108 which biases the
lowermost cell 12 against the lowermost connection plate 204 of the
cooling module 10 i.e. presses it into contact there, in order to
favor the transporting way of heat from this cell. One can
furthermore see in FIG. 8A that in each case two threaded inserts
120 are provided at the first and second longitudinal side 122, 124
of the lower half 122 of the housing and that further threaded
inserts 126 are provided at a corresponding spacing from the inner
side of the base part of the lower half of the housing. These serve
for the screwing on and attachment of the cooling module 10 and the
battery module within the housing.
[0100] The upper half 128 of the housing is similarly designed
except that here the ribbing 130 which is provided for the
stiffening of the upper side of the upper half 128 of the housing
111 is provided on the inner side of the upper half of the housing.
This ribbing 120 lies in the assembled state of the housing 111
with the installed battery module 14 at the upper broad side of the
upper cell 12', if required via a foam material inlay and presses
the upper cell 12' against the upper connection plate 20' in order
to ensure a good heat transfer there also.
[0101] From FIG. 8C one can see that the front longitudinal side
132 of the upper half of the housing has two bores 134 which enable
screws to be inserted which engage in the corresponding threaded
inserts 120 of the first longitudinal side 122 of the lower half
112 of the housing 111. Two further bores are provided at the rear
longitudinal side 136 of the upper half 128 of the housing 111 in
accordance with FIG. 8C but are however not evident there but
rather in the illustration of FIG. 8D.
[0102] As can be found from the finished housing with the installed
battery module in accordance with FIG. 8E the two poles 66 and 70
or the inner threads 80, 82 provided there are accessible through
the bores 138 so that there the electrical connection can be
effected. The electrical connection thus takes place from the upper
side of the battery housing but beneath the upper side. The
electrical connection cable can also be guided beneath the upper
side of the housing, for example within the step which extends
around the upper side, so that the electrical lines do not enlarge
either the constructional height of the module or the installed
height in the vehicle. The tubular inlet 26 and the tubular outlet
28 for the cooling system or the corresponding connection glands
30, 32 project through the bores 140 of the upper half of the
housing. Here also the coolant connection takes place below the
upper side of the battery module and it is also possible here to so
guide the external connection hoses that they do not increase the
constructional height of the battery module or its installed
height. If required the said steps can be made larger or deeper in
order to enable this.
[0103] Furthermore, the battery management system is provided with
a plug which is accessible through the opening 142 at the upper
side 146 of the upper half 128 of the housing 111, with the housing
111 being equipped here with two thread inserts 148 which serve to
accommodate fastener bolts of the plug.
[0104] The housing is a two-part injection molded component and can
have the following design: The critical dimension is the short side
(constructional height 155 mm). In this connection the connections
(poles, cooling and data) are executed in sunk matter. The data
plug is in practice sunk still further in order to enable a seal
without additional constructional space. The dimensions can for
example be selected as follows:
[0105] Base dimension: ca. 300.times.245.times.155 mm
[0106] Volume: ca. 111
[0107] Energy density: ca. 152 Wh/l
[0108] Mass: ca. 14.15 kg
[0109] Specific energy: ca. 122 Wh/kg.
[0110] The two housing halves 112, 128 can be closed against one
another with a periphery extending groove and tongue system for
sealing. If required the battery management plug can be provided
with a sealed cap and seals can be provided between the housing and
the coolant connection tubes 26, 28.
[0111] The modules can however be integrated with or without a
housing to form a battery. The system limit and the functions which
are to be realized thereby such as for example sealing against
contaminants from the out- side, EMV and mechanical reliability can
thus be flexibly placed around the module up to the complete
battery. The module without the outer housing (cell stack) can for
example be welded into a foil. These stacks are then installed in a
number greater than 1 into a system housing.
[0112] Starting from a battery module system with eight individual
battery modules 14 of the above-described kind some considerations
in accordance with the invention relating to the cooling system
will now be described.
[0113] Before the design of the cooling system is described in more
detail it is appropriate to say some few words about the cooling of
a traction battery system and for the air conditioning requirement
in a vehicle which has the battery system.
[0114] A main goal of the cooling system in accordance with the
invention is to ensure the operating reliability of the traction
battery system with the motivation to avoid the exceeding of
specific temperature limits which could otherwise lead to a
permanent damage of the battery system and in an extreme case to
fire or explosion. In order to achieve this, the battery system is
cooled and indeed with the object of not exceeding dangerous and
damaging temperature limits. For many battery technologies the
temperature should not rise above 30.degree. C. in order to obtain
a maximum working life. In accordance with experience each
temperature increase by 10.degree. C. above 30.degree. C. leads to
a reduction in working life by ca. one half which is however
technology-dependent.
[0115] For a traction battery system a thermal conditioning
requirement also exists, for example in order to improve the cold
starting behavior. This is necessary because at low temperatures
the performance of the cells that are used reduces greatly. In
order to counteract this the battery system must for example be
heated in winter operation.
[0116] In general, in accordance with the concept of the invention,
the traction battery system--which normally consists of a plurality
of battery modules--and/or the individual battery modules are
thermally well insulated. This prevents the battery modules or the
cells contained therein cooling down rapidly with the consequence
that they subsequently have to be heated up in a costly manner in
order to enable the renewed starting of the vehicle.
[0117] One possibility of heating the battery cell is to use a
resistance heating which directly contacts the electrically
conducting spacer elements. For example a resistance heater can be
provided for each conductive spacer element. Since the electrically
conductive spacer elements are naturally thermally well conducting
and have a high quality electrical and heatconducting connection or
transfer to the metallic lugs of the electrodes of the cells the
electrically generated heat can be introduced directly into the
interior of the respective cells which is particularly
energy-efficient for heating up of the cells. In a well insulated
arrangement an energy input of 1 Watt per cell is already
sufficient. This energy can be delivered by the battery modules
themselves or during the charging of the battery modules from the
power supply or from an associated combustion engine, combustion
heater or fuel cell system. The resistors can also be attached to a
circuit board which belongs to the battery management system and is
pressed against the spacer elements.
[0118] The heating up of the battery modules can also be achieved
alternatively to the described electrical heating via the cooling
system that is present, as well be explained in more detail
below.
[0119] Furthermore, it is appropriate to thermally insulate the
individual battery modules per se and/or in the assembly relative
to the environment in order, on the one hand, to store the
self-heat of the batteries and, on the other hand, to reduce heat
losses on heating of the batteries. If for example the battery
system has a temperature in operation close to 30.degree. C. one
can, by suitable insulation within the module housing and/or
outside of the module housing, reduce the heat loss of the battery
system so that the battery system does not cool down very rapidly
and remains adequately warm in order, after a break in a journey,
to be able to economically start operation again.
[0120] A temperature equilibrium between the cells of the
individual battery modules 14 should also take place with the
motivation of exploiting the capacity of the cells to a maximum and
to make the available power a maximum over the full working life.
This also requires the cooling or indeed the heating of the
individual cells 12 of the battery module 14. One aims at a uniform
temperature level which leads to an equivalent cell behavior and to
uniform discharge and aging of the cells. In other words, through
the correct temperature level and a corresponding temperature
equalization, one can ensure that all cells 12 make available the
maximum power over the longest possible time period and that on
achieving the maximum working life all cells 12 are at the end of
their respective working lives, so that an economical exchange of
battery modules 14 can take place, since one does not have to
prematurely exchange individual battery modules and, on failure of
one battery module 14 all cells 12 are likewise at the end of their
working life.
[0121] Two possibilities for the heat transfer from or to the cells
12 of an individual battery module 14 are basically conceivable. An
energy exchange of the cell 12 with the environment can either take
place by air cooling or by liquid cooling. With air cooling a
direct contact is required between the cell housing and the
environmental air but the poor thermal conductivity and the low
density of the air require large volumetric flows and large
exchange surfaces as well as a pronounced generation of noise.
[0122] In contrast, for liquid cooling, a better transfer of the
energy can take place via heat conduction and convection from the
housing 111 into a liquid coolant and following this via convection
into the environmental air. With liquid cooling a better thermal
conductivity can be achieved since the heat-conducting elements 16,
18, 20, 52, 46, 36, 38 stand in direct contact with the cells 12
and these, together with a heat exchanger cooling the liquid
coolant permits smaller volume flows and exchange surfaces and also
lower noise generation. The use of liquid cooling does however
necessitate additional components in the form of hose connections
and seals and also a heat exchanger to the environment.
[0123] If one decides for liquid cooling then one must
simultaneously employ considerations in connection with the
hydraulic design of the entire cooling system. Pressure losses
arise in the tubes/hoses/cooling passages and components of the
cooling system. For flow elements in the form of tubes with round
cross-section and corresponding bends one can estimate these
pressure losses with empirical formulae. In addition to the
resistances in each cooling module the external loops and also the
radiator introduce resistances into the circuit which must
additionally be taken into account as soon as a design concept is
present. The pump which is required for the circulation of the
coolant imposes a volume flow against these resistances which is
dependent on these resistances and generates a stable working point
there where the pressure which can be supplied by the pump
intersects the characteristic of the cooling system in the form of
volume flow as a function of the applied pressure. It is
particularly favorable when a small pump for the liquid coolant is
used, for example a small automotive circulation pump with a
typical power of 10 to 30 W which can achieve a volume flow per
module of >50 1/h for a pressure loss in the system of 75 to 450
mbar.
[0124] The FIG. 10A shows a possibility of connecting the cooling
modules 10 of all eight battery modules 14 in series. This is
however not a favorable arrangement because the temperature of the
cooling system consisting of the eight cooling modules 10 connected
in series with one another continuously rises so that the last
module 10' or 14' is the hottest.
[0125] If, in contrast, all cooling modules 10 are connected in
parallel in accordance with FIG. 10B then one can ensure in this
manner that all modules have the same coolant temperature.
[0126] However, if all eight modules are connected in parallel in
accordance with this example then one must make an addition of
effort in order to ensure that the volume flow is the same for each
module 10.
[0127] It is more favorable, as shown in FIG. 10C, to use mixed
forms in which several cooling paths are arranged in parallel to
one another and with a plurality of modules 10 connected in series
in each cooling path. The consideration is to decide how many
modules are to be connected in series without the temperature
difference which arises becoming too large.
[0128] After extensive considerations and investigations the
applicants are of persuasion that the temperature difference which
can be tolerated should not exceed 5.degree. C.
[0129] Furthermore it has been found that a cooling system which
operates economically and which can be realized economically can
then be most favorably realized when, in a battery module system
consisting of a plurality of like battery modules 14 with
respective cooling modules 10, these are so connected together or
can be so connected together that a plurality of cooling circuits
150 arise which are fed via a distributor pipe 152 and also
connected to a collector pipe 154. Each cooling circuit 150 can
include in each case two to four cooling modules 10 or battery
modules 14 in series, with the cooling passages within the battery
module 14 each having a free flow cross-section corresponding to
that of a pipe having a clear internal diameter of 8 to 9 mm.
[0130] Some examples of such a cooling system can be found in the
FIGS. 11A to 11D.
[0131] In the embodiment of FIG. 11A two battery modules or cooling
modules 10 are connected in series in accordance with FIGS. 1 to 3,
i.e. each battery module 14 or cooling module 10 has an inlet 26
and an outlet 28 which can be realized by the hydraulic design of
each cooling module in accordance with FIG. 9, with the outlet 28
of the first cooling module 10 of the two modules 10, 10' connected
in series being connected to the inlet 26 of the next module 10' in
the flow direction and the inlet 26 of the first of the two modules
10, 10' connected in series being connected to the distributor pipe
152 and the outlet of the two modules 10' connected in series being
connected to the collection pipe 156. Alternatively one could
operate here in accordance with FIG. 11B. Here the cooling passages
through the individual cooling plates 16, 18 of the respective
module 10 are not connected via a connection line 34 but rather
each module has two separate inlets 26 and two separate outlets 28
namely one inlet and one outlet for each cooling plate 16, 18. With
an arrangement of this kind up to four modules 10 can
straightforwardly be connected in series, as shown in FIG. 11B, so
that parallel flow paths 158 (four parallel flow paths 158 in FIG.
11B) are produced, with the two rows 160 of modules which results
being connected as previously to the distributor pipe 152 and the
collecting pipe be 156.
[0132] If required, a plurality of cooling modules 10, i.e. battery
modules 14 can be connected together with the system
correspondingly supplemented in accordance with FIG. 11A or FIG.
11B. For example, if twelve battery modules 14 with twelve cooling
modules 10 are provided instead of eight battery modules 14 with
eight cooling modules 10 then, in accordance with FIG. 11D, the
three battery modules or cooling modules 10, 10', 10'' will in each
case be connected in series instead of two battery modules or two
cooling modules as shown in FIG. 11A. In contrast, with a
corresponding extension of the example in accordance with FIG. 11B,
in FIG. 11C six modules will in each case be connected in series
instead of four modules 10 in FIG. 11B.
[0133] The tables in accordance with FIGS. 12A and 12B indicate,
for two different power extraction rates (1.5 C and 2 C) how the
temperature difference at the cooling modules or battery modules
works out in practice, depending on how many modules are connected
in parallel to one another and depending here on how many series
modules are considered. The values given in FIGS. 12A and 12B apply
for a tube diameter of 8 mm which determines an equivalent flow
cross-section through the flow passages of the cells.
[0134] The areas of the table in accordance with FIGS. 12A and 12B
provided with a dot show systems which, for different extraction
powers, operate with a temperature difference between inlet and
outlet of smaller than 5.degree. C. One can see that the
temperature difference depends on the power extraction rate (in
these examples 1.5 C and 2 C respectively) and that, for example, a
variant with twelve battery modules and up to three modules in
series is well suited since reserves are present up to 2 C.
Naturally, in this consideration, one not only has to consider the
extraction rate but rather, at the same time, also the level of the
required quantity of energy which for a smaller vehicle can
certainly lie in the range between 16 and 40 kWh. In comparison to
a clear internal pipe diameter of 6 mm a significantly better
efficiency manifests itself with a clear internal pipe diameter of
8 mm, because the temperature difference AT is ca. 50% smaller. In
contrast an increase of the clear internal pipe diameter to 9 mm
does not lead to any further pronounced improvement.
[0135] In FIG. 13 one can see that the distributor pipe 152 and the
collection pipe 156 communicate with a main line 160 which has a
pump 162 and a radiator 164, in this case with fan 166. When the
temperature of the coolant threatens to exceed a specific limit,
the fan 166 is switched on in order to additionally cool the liquid
coolant flowing through a main line and the radiator, i.e. in
addition to the normal air flow through the radiafor 164, which is
correspondingly placed in the vehicle and through which air flowing
past the vehicle flows.
[0136] As additionally shown in FIG. 14 the main line 160 can
furthermore have a heat exchanger 168 with at least one further
circuit which feeds a heating system or an air conditioning system
172. In this manner the excess heat which is removed from the
battery modules 14 by the cooling system is used to heat the
interior compartment of a vehicle which is equipped with the
traction battery system. If required a coolant circuit which is
cooled by an air conditioning compressor can serve for additional
active cooling of the system. If required the heating can also be
supplied with energy from the outside in order to heat the cells 12
of the individual battery modules 14 via the cooling system,
insofar as this is necessary in order to bring the cells to a
reasonable battery operating temperature level. The cooling system
operates then in this mode as a heating system for battery modules.
As soon as a reasonable operating temperature is achieved the
additional heating is stopped and the vehicle can be taken into
operation using the energy of the traction battery system. Should
an external energy source not be available for the heating of the
battery, for example when the vehicle is parked at night on the
road, then a part of the still present energy of the batteries can
be used to heat up the batteries, for example by connecting the
battery power to an electrical heating device of the heating system
172 which temporarily heats the liquid coolant and a part of the
electrical energy can also be used in order to operate the pump 162
and hereby to circulate a heated liquid coolant through the
individual cells 12.
[0137] Referring to FIG. 15 an alternative embodiment of the
connection terminals or lugs 36, 38 of the cells 12 is shown.
Instead of having U-shaped cutouts 37 and 39 at one side, such as
are shown for the connection terminals of FIG. 2B, circular
openings 37' and 39' are provided here in the two connection
terminals 36, 38 which represent a continuation of the positive (*)
and negative (-) electrodes of the cell 12. Although, as also shown
in FIG. 2B, two cutouts are provided here in each case a different
number of cutouts can also be provided, such as for example the
three U-shaped cutouts of FIG. 17A.
[0138] The connection terminals 36, 38 themselves consist of sheet
aluminum or sheet copper of low thickness such as for example
(without restriction) 0.3 mm.
[0139] In practice it is relatively difficult to achieve a
connection to such a connection terminal of aluminum with a
continuously low contact resistance over a period of time of
several years. On the one hand, an insulating oxide layer forms on
an aluminum sheet in a short period of time. On the other hand,
metallic corrosion which exists on contacting of the contact
terminals and clamping forces which possibly change over a longer
period of time, and which are in turn frequently
temperature-dependent, must be counter-acted.
[0140] In order to provide assistance here, conductive spacer
elements in accordance with FIGS. 16A and 16B and insulating spacer
elements in accordance with FIGS. 16C and 16D are preferably used.
Spacer elements 44, 46 of the same kind are thus used both for the
embodiment of the connection terminals in accordance with FIG. 2B
and also for those in accordance with FIG. 15 (i.e. apart from the
shape of the cutouts 37, 39 and 37', 39') respectively.
[0141] Specifically the conductive spacer element 44 in accordance
with FIG. 16A consists of a block 200 of aluminum having the shape
of parallelepiped with two through holes 202 which correspond in
diameter to the diameter of the circular openings 37' and 39'
respectively of the embodiment of FIG. 15 and to the diameter of
the rounded base of the U-shaped cutouts 37 and 39 respectively of
the embodiment in accordance with FIG. 2B. As can be seen from the
sectional drawing in accordance with FIG. 16B (at the section plane
XVIB-XVIB of FIG. 16A) the block 200 of aluminum is provided on all
sides with a galvanic nickel coating 204. The upper and lower sides
206, 208 of the coated aluminum block are roughened, for example by
sand blasting, grinding, brushing or otherwise, whereby smaller
raised portions and recesses arise or are present at the said sides
206 and 208. These dig slightly into the surface of the connection
terminals 36, 38 on clamping of the battery module, break-through
the oxide layer there and produce an excellent contact with the
connection terminals. The nickel coating 204 can also be provided
inside the holes 202, this is however not necessary.
[0142] The insulating spacer elements 46 of FIGS. 16C and 16D have
a shape which is at least substantially identical to that of the
spacer elements 44 of FIGS. 16A and 16B. Here also they consist of
an aluminum block 210 having the shape of a parallelepiped. In
order to ensure that the so conceived spacer elements are
insulating the corresponding aluminum blocks are anodized over
their full area whereby a thin high quality insulating layer 212
arises on all surfaces of the blocks. If the bores 214 have already
been manufactured previously, then this anodized layer is also
present in the bores 214 (not shown). In order to ensure that any
damage to the anodized layer, which is in any event hard, does not
lead to an undesired conducting transition between the insulating
spacer element 46 and a conductive spacer element 44 or to a
connection terminal 36, 38 of the battery cell a further insulating
layer 216 is deposited on the anodized layer. This layer 216 can,
even if not so shown in FIG. 16D, also be deposited within the
bores 212, optionally on an anodized layer provided there. The
insulating layer 216 is a very thin layer of an organic or
inorganic compound or a paint layer or an insulating paint or a
resin layer of a corresponding insulating resin.
[0143] The nickel layer 204 of the conducting spacer element in
accordance with FIGS. 16A, 16B and the anodized layer 212 and also
the insulating layer 216 applied thereon are kept comparatively
thin, for example approximately 200 .mu.m for the nickel layer 204
and the anodized layer 212 and approximately 300 .mu.m for the
insulating layer 216. Since both the conductive spacer elements 44
and also the insulating spacer elements 46 consist at least
substantially of aluminum, the thermal expansion of the spacer
elements as a whole correspond approximately to the thermal
expansion of aluminum. Furthermore, as the clamping bolts
preferably consist of aluminum it is ensured (because the thermal
expansion coefficients of the parts other than the thin coatings
are at least substantially the same) that after tightening of the
nuts of the threaded bolts an at least substantially constant
clamping force arises between the conductive spacer elements 44,
the insulating elements 46 and the connection terminals of the
battery cells of the battery module irrespective of what
temperature fluctuations arise in practice. This clamping force not
only ensures that the unevenness of the nickel coating 204 of the
conducting spacer elements produces a good electrical contact to
the connection terminals of the battery cells but rather the
clamping pressure also leads to a type of seal between the surfaces
which contact one another so that moisture or corrosion promoting
substances cannot straightforwardly lead to a deterioration of the
conducting transitions between the conducting spacer elements 44
and the connection terminals 36, 38.
[0144] The use of aluminum as a basic material of the conducting
spacer elements 44 and of the insulating elements 46 lend itself
because, on the one hand, this is the same material as the
connection terminals 36, 38 and, on the other hand, aluminum has a
low density so that the weight of the battery module can be kept
small. It would however also be conceivable to make both the
conducting spacer elements and also the insulating spacer elements
of a different material, it would then be appropriate to make the
clamping bolts of the same material or of a material with a
comparable coefficient of thermal expansion in order to achieve the
desired at least substantially constant clamping force.
[0145] FIG. 17 shows an alternative embodiment of the cooling
plates 16, 18 of the FIG. 1. These cooling plates are converted in
FIG. 17 into a unitary structure so that a three-sided cooling
plate arrangement 220 results. More specifically, the cooling plate
222 at the right-hand side 223 of the cooling module 220 of FIG. 17
merges via a cooling plate 224 at the rear side 225 of the cooling
module 220 into the cooling plate 226 of the left-hand side 227.
Furthermore, the cooling passages 228 of the cooling plates are
made parallel in the sense that all individual cooling passages 228
of the cooling plates are guided parallel to one another and with a
uniform spacing around the three sides 223, 225, 227 of the cooling
module and extend between a distribution passage at the left-hand
side 227 on the cooling module 220 via the rear side 225 to a
collection passage 230 at the right-hand side 223 of the cooling
module 230.
[0146] The distribution passage at the left-hand side 226 is
identically constructed to the collection passage 230 at the
right-hand side 22. The collection passage 230 communicates via a
long narrow connection passage 232 with the tube-like outlet 28
having the hose connection gland 32. In just the same way the
tubular inlet 26 with the hose connection gland 30 communicates via
an elongate connection passage (not visible in FIG. 17) with the
distribution passage (likewise not visible). Liquid coolant thus
flows through the hose connection gland 30 between the tube-like
inlet 26 from their via the said elongate connection passage in the
distribution passage into the individual passages 228 of the
cooling module 220 which extend parallel to one another across the
left-hand side 227 of the cooling module 220 and subsequently
across the rear side 225 of the cooling module and across the
right-hand side 223 of the cooling module 220 into the collection
element 230 and then via the elongate connection passage 232 to the
tubular outlet 28 and via the hose connection gland 32 into the
cooling circuit again.
[0147] In this embodiment the sheet metal cooling plates and the
connection plates 20 are provided with side parts with right angles
at the left-hand side 227 and the right-hand side 223 through the
cooling modules 220 and also at the rear side 225 and these are
then adhesively bonded, welded or soldered onto planar sheet metal
parts at the inner left, rear and right sides 227, 225 and 223 of
the cooling module 220 in order to produce a good thermal
transition between the connection plates 20 and the cooling plates
at the three sides 227, 225, 223.
[0148] The outer side of the cooling plate regions 222, 224, 226 of
the cooling module 220 is likewise formed by a sheet metal part
which is depressed, in a similar manner to the sheet metal part of
FIGS. 7A to 7D at positions in order to form ribs 99 which form the
coolant passages 222 including the connection passage from the
tubular inlet 26 into the distribution passage and the transition
on the other side of the cooling module 220 into the collection
element 230 and the connection passage 232 into the tubular outlet
26. The inner planar sheet metal parts are connected to the outer
sheet metal parts by means of adhesive bonding, welding, soldering
or otherwise.
[0149] FIG. 17 furthermore shows a comb-like part 240 with slots
242 which are arranged at the spacing of the individual connection
terminals 36, 38 of the individual cells and have dimensions which
receive the connection terminals. In this manner the comb-like
insulating plate 240 can be pushed as the arrows 244 show onto the
connection terminals 36, 38 of the cells in order to hold these in
ordered arrangement and in order to ensure that the insertion of
the conducting spacer elements 44 and the insulating spacer
elements 46 can be introduced in ordered manner between adjacent
connection terminals 36, 38.
[0150] A like plate can also be provided with the battery module of
FIG. 2A and here it is possible for the rear side of the cooling
modules to be opened, to push the cells forwardly through the slits
242 of the comb-like plate and also to push the plate onto the
already installed cells.
[0151] In FIG. 17 the comb-like plate is shown with a central
stiffening rib 246. This is however not absolutely essential.
REFERENCE NUMERAL LIST
[0152] 10 cooling module [0153] 12 cells [0154] 14 battery module
[0155] 16 cooling plate [0156] 18 cooling plate [0157] 20
connection plate [0158] 22 compartment [0159] 24 side part of the
connection plates [0160] 26 tubular inlet [0161] 28 tubular outlet
[0162] 30 hose connection gland [0163] 32 hose connection gland
[0164] 34 connection line [0165] 36 positive terminal [0166] 37
U-shaped cutout [0167] 37' circular opening [0168] 38 negative
terminal [0169] 39 U-shaped cutout [0170] 39' circular opening
[0171] 40 left-hand row [0172] 42 right-hand row [0173] 44
conductive spacer element [0174] 46 insulating spacer element
[0175] 48 clamping device [0176] 50 clamping bolt [0177] 52
heat-conducting plate [0178] 54 right-hand end of the plate 52
[0179] 56 left-hand end of the plate 52 [0180] 57 rivet connection
[0181] 58 insulating sleeve [0182] 60 end of a clamping bolt with
thread [0183] 62 nut [0184] 63 washer [0185] 66 positive pole
[0186] 68 first upper end of the left-hand row [0187] 70 negative
pole [0188] 72 second lower end of the left-hand row [0189] 74
conducting plate [0190] 76 extension [0191] 78 first upper end of
the right-hand row [0192] 79 insulating plate [0193] 80 internal
thread of one pole terminal [0194] 82 internal thread of the other
pole terminal [0195] 84 spacer element [0196] 85 base plate [0197]
86 lugs [0198] 88 first vertical section of the cooling passage
[0199] 90 second horizontal section of the cooling passage [0200]
92 third vertical section of the cooling passage [0201] 94 fourth
horizontal section of the cooling passage [0202] 96 fifth vertical
section of the cooling passage [0203] 98 sixth horizontal section
of the cooling passage [0204] 99 ribs [0205] 100 seventh vertical
section of the cooling passage [0206] 102 eighth horizontal section
of the cooling passage [0207] 104 ninth vertical section of the
cooling passage [0208] 106 tenth horizontal section of the cooling
passage [0209] 108 lugs [0210] 109 ribs [0211] 110 sheet metal
cover [0212] 111 housing [0213] 112 lower half of the housing
[0214] 114 lower side of the housing [0215] 116 ribbing of the
lower side of the housing [0216] 118 foam material [0217] 120
thread insert [0218] 122 first longitudinal side of the lower half
of the housing [0219] 124 second longitudinal side of the lower
half of the housing [0220] 126 thread insert [0221] 128 upper half
of the housing [0222] 130 projection [0223] 132 first longitudinal
side of the upper half of the housing [0224] 134 bores [0225] 136
rear longitudinal side of the upper half of the housing d128 [0226]
138 bores [0227] 140 bores [0228] 142 opening [0229] 144 threaded
bores [0230] 146 top side of the housing 111 [0231] 148 thread
inserts [0232] 150 cooling circuit [0233] 152 distribution pipe
[0234] 154 collection pipe [0235] 156 collection tube [0236] 158
parallel cooling path [0237] 160 main line [0238] 162 pump [0239]
164 radiator [0240] 166 fan [0241] 168 heat exchanger [0242] 170
further circuit [0243] 172 heating/air conditioning system [0244]
200 aluminum block [0245] 202 passage holes [0246] 204 nickel
coating [0247] 206 top side of 200 [0248] 208 bottom side of 200
[0249] 210 aluminum block [0250] 212 anodized layer [0251] 214
bores [0252] 216 insulating layer [0253] 220 cooling plate
arrangement/cooling module [0254] 222 right-hand cooling plate
[0255] 223 right-hand side of 220 [0256] 224 rear cooling plate
[0257] 225 rear side of 220 [0258] 226 left-hand cooling plate
[0259] 227 left-hand side of 220 [0260] 228 cooling passages [0261]
230 collection passage [0262] 232 connection passage [0263] 240
comb-like part [0264] 242 slits [0265] 242 arrow direction [0266]
246 stiffening ribs [0267] 302 circuit board for battery management
system [0268] 304 screws for circuit boards 302
* * * * *