U.S. patent application number 17/066822 was filed with the patent office on 2021-01-28 for battery pack containing phase change material.
The applicant listed for this patent is CONSORTIUM DE RECHERCHE BRP - UNIVERSITE DE SHERBROOKE S.E.N.C.. Invention is credited to Normand LEBREUX, Eric MENARD.
Application Number | 20210028516 17/066822 |
Document ID | / |
Family ID | 1000005137427 |
Filed Date | 2021-01-28 |
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United States Patent
Application |
20210028516 |
Kind Code |
A1 |
LEBREUX; Normand ; et
al. |
January 28, 2021 |
BATTERY PACK CONTAINING PHASE CHANGE MATERIAL
Abstract
A battery pack for a vehicle including a first module group
comprising at least one battery module; a second module group
comprising at least one other battery module; and a manually
operable interrupter assembly selectively electrically connecting
the first module group to the second module group in series, the
interrupter assembly being adapted for opening and closing a
circuit connecting the first and second module groups.
Inventors: |
LEBREUX; Normand;
(Sherbrooke, CA) ; MENARD; Eric; (Sherbrooke,
CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
CONSORTIUM DE RECHERCHE BRP - UNIVERSITE DE SHERBROOKE
S.E.N.C. |
Sherbrooke |
|
CA |
|
|
Family ID: |
1000005137427 |
Appl. No.: |
17/066822 |
Filed: |
October 9, 2020 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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16158410 |
Oct 12, 2018 |
10840570 |
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17066822 |
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15546232 |
Jul 25, 2017 |
10128550 |
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PCT/IB2016/050511 |
Feb 1, 2016 |
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16158410 |
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62109970 |
Jan 30, 2015 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01M 2200/00 20130101;
Y02T 10/70 20130101; B60L 50/64 20190201; B60L 58/18 20190201; H01M
10/659 20150401; C09K 5/063 20130101; H01M 10/625 20150401; B60L
50/66 20190201; H01M 2220/20 20130101; H01M 10/613 20150401; H01M
50/502 20210101; H01M 50/20 20210101; H01M 50/572 20210101 |
International
Class: |
H01M 10/659 20060101
H01M010/659; H01M 10/625 20060101 H01M010/625; C09K 5/06 20060101
C09K005/06; H01M 2/10 20060101 H01M002/10; H01M 2/20 20060101
H01M002/20; H01M 10/613 20060101 H01M010/613; H01M 2/34 20060101
H01M002/34; B60L 50/64 20060101 B60L050/64; B60L 58/18 20060101
B60L058/18; B60L 50/60 20060101 B60L050/60 |
Claims
1. A battery pack for a vehicle, comprising: a first module group
comprising at least one battery module; a second module group
comprising at least one other battery module; and a manually
operable interrupter assembly selectively electrically connecting
the first module group to the second module group in series, the
interrupter assembly being adapted for opening and closing a
circuit connecting the first and second module groups.
2. The battery pack of claim 1, wherein: a nominal voltage of each
of the first and second module groups individually is less than a
high voltage limit; and when the circuit is closed by the
interrupter assembly, the first and second module groups are
connected in series and a nominal voltage of the battery pack is
greater than the high voltage limit.
3. The battery pack of claim 1, wherein the high voltage limit is
60 Volts.
4. The battery pack of claim 2, wherein: when the circuit is closed
by the interrupter assembly, the nominal voltage of the battery
pack is 96 Volts; and when the circuit is opened by the interrupter
assembly, the nominal voltage of each of the first and second
module groups is 48 Volts.
5. The battery pack of claim 3, wherein: when the circuit is closed
by the interrupter assembly, the nominal voltage of the battery
pack is 96 Volts; and when the circuit is opened by the interrupter
assembly, the nominal voltage of each of the first and second
module groups is 48 Volts.
6. The battery pack of claim 1, wherein: each module group
comprises at least two battery modules connected in series.
7. The battery pack of claim 1, wherein: the first module group is
mounted to a first location in the vehicle; the second module group
is mounted to a second location in the vehicle; and the first
location and the second location are spaced apart.
8. The battery pack of claim 1, wherein each one of the at least
one battery module and the at least one other battery module
comprises: a plurality of bricks, each brick comprising: a phase
change material block; and a plurality of battery cells disposed at
least in part in the phase change material block.
9. The battery pack of claim 2, wherein each one of the at least
one battery module and the at least one other battery module
comprises: a plurality of bricks, each brick comprising: a phase
change material block; and a plurality of battery cells disposed at
least in part in the phase change material block.
Description
CROSS-REFERENCE
[0001] The present application is a divisional application of U.S.
patent application Ser. No. 16/158,410, filed Oct. 12, 2018. U.S.
patent application Ser. No. 16/158,410 is a divisional application
of U.S. patent application Ser. No. 15/546,232, filed Jul. 25,
2017, which issued as U.S. Pat. No. 10,128,550, on Nov. 13, 2018.
U.S. patent application Ser. No. 15/546,232 is a national stage
entry of International Application No. PCT/M2016/050511, filed Feb.
1, 2016, which claims priority to United States Provisional Patent
Application No. 62/109,970, filed Jan. 30, 2015. The entirety of
each application is incorporated herein by reference.
FIELD OF TECHNOLOGY
[0002] The present technology relates to rechargeable battery packs
for use in vehicles.
BACKGROUND
[0003] It is known to use phase-change materials (PCM) for thermal
management of battery packs. For example, U.S. Pat. No. 6,468,689
(Al-Hallaj et al.), U.S. Pat. No. 6,942,944 (Al-Hallaj et al.) and
U.S. Pat. No. 8,273,474 (Al-Hallaj et al.), all issued to Allcell,
each disclose a PCM comprising a paraffin wax for use in a pack
comprising rechargeable battery cells. Each of these patents is
incorporated herein by reference.
[0004] An example of such a PCM material is the Phase Change
Composite (PCC.TM.) thermal management material from AllCell
Technologies LLC.
SUMMARY
[0005] It is an object of the present technology to improve current
rechargeable battery packs, in particular for use in vehicles such
as motorcycles, all-terrain-vehicles, snowmobiles, personal
watercraft and the like.
[0006] In one aspect, implementations of the present technology
provide a battery pack including a plurality of modules connected
in series, each module having a nominal voltage of between 18 Vdc
and 32 Vdc, the plurality of modules having a combined nominal
voltage of between 84 Vdc and 112 Vdc, each module comprising
between six and 20 bricks connected in series, each brick including
between ten and 60 electrochemical cells connected in parallel; and
a phase change material for dissipating at least a portion of heat
generated upon activation of at least a portion of the
electrochemical cells, the phase change material at least in part
enveloping the electrochemical cells.
[0007] In another aspect, implementations of the present technology
provide a battery pack including:
[0008] a plurality of electrochemical cells having a
T.sub.max-charge and a phase change material for dissipating at
least a portion of heat generated upon activation of at least a
portion of the electrochemical cells, the phase change material at
least in part enveloping the electrochemical cells, the phase
change material having a T.sub.melt<T.sub.max-charge.
[0009] In another aspect, implementations of the present technology
provide a battery pack comprising a plurality of bricks connected
in series, each brick including:
[0010] a plurality of electrochemical cells, and
[0011] a phase change material for dissipating at least a portion
of heat generated upon activation of at least a portion of the
electrochemical cells, the phase change material at least in part
enveloping the electrochemical cells, the plurality of
electrochemical cells being disposed in an alternating pattern
within the phase change material,
[0012] wherein the alternating pattern enables the formation of
channels between at least some of the electrochemical cells,
and
[0013] wherein the battery pack further comprises connectors for
conductively connecting adjacent bricks, the connectors being
disposed within the channels.
[0014] In another aspect, implementations of the present technology
provide a battery pack including:
[0015] a plurality of electrochemical cells,
[0016] a phase change material for dissipating at least a portion
of heat generated upon activation of at least a portion of the
electrochemical cells, the phase change material at least in part
enveloping the electrochemical cells,
[0017] a housing for containing the plurality of electrochemical
cells and the phase change material, the housing made of a metallic
material, and
[0018] a layer of thermally conductive adhesive between the at
least a part of the phase change material and the housing.
[0019] According to another aspect of the present technology, there
is provided a battery brick for a vehicle, comprising a phase
change material having a melting temperature; and a plurality of
battery cells, each battery cell of the plurality of battery cells
being disposed at least in part in the phase change material, the
plurality of battery cells having a maximum charge temperature and
a maximum discharge temperature, the maximum charge temperature of
the battery cells being less than the maximum discharge
temperature, the phase change material being adapted for
dissipating at least a portion of heat generated upon activation of
at least a portion of the plurality of battery cells, the melting
temperature of the phase change material being less than the
maximum charge temperature of the plurality of battery cells.
[0020] According to another aspect of the present technology, there
is provided a battery pack for a vehicle, comprising a plurality of
battery modules connected to one another, each of the plurality of
battery modules comprising a plurality of the battery bricks.
[0021] In some implementations of the present technology, the
plurality of battery modules are connected to one another in
series.
[0022] In some implementations of the present technology, the
plurality of battery bricks are connected to one another in
parallel.
[0023] According to yet another aspect of the present technology,
there is provided a battery pack for a vehicle, comprising a
plurality of bricks, each brick of the plurality of bricks
comprising a phase change material block, a side of the phase
change material block defining a plurality of channels, and a
plurality of battery cells, each battery cell being disposed at
least in part in the phase change material block; and at least one
connector for electrically connecting a first one of the plurality
of bricks to a second one of the plurality of bricks, the at least
one connector being disposed at least partially in one of the
plurality of channels.
[0024] In some implementations of the present technology, the first
one of the plurality of bricks is adjacent to the second one of the
plurality of bricks.
[0025] In some implementations of the present technology, the
plurality of bricks are electrically connected to one another in
series.
[0026] In some implementations of the present technology, the side
of the phase change material block is a top side of the phase
change material block.
[0027] In some implementations of the present technology, the first
one of the plurality of bricks further comprises a positive current
collector electrically connected to the plurality of battery cells
of the first one of the plurality of bricks; the second one of the
plurality of bricks further comprises a negative current collector
electrically connected to the plurality of battery cells of the
second one of the plurality of bricks; and the at least one
connector electrically connects the positive current collector of
the first one of the plurality of bricks to the negative current
collector of the second one of the plurality of bricks.
[0028] In some implementations of the present technology, the
battery pack further comprises at least one insulator disposed
between the positive current collector of the first one of the
plurality of bricks and the negative current collector of the
second one of the plurality of bricks.
[0029] In some implementations of the present technology, the at
least one connector is a plurality of connectors, each one of the
plurality of connectors being disposed in a corresponding one of
the plurality of channels.
[0030] In some implementations of the present technology, wherein
for each brick of the plurality of bricks, the plurality of battery
cells are arranged in an alternating pattern, wherein the plurality
of battery cells are arranged in a plurality of columns, and
adjacent columns of the plurality of columns are vertically
staggered from one another; and at least one of the plurality of
battery cells is disposed between two of the plurality of
channels.
[0031] In some implementations of the present technology, the at
least one connector is a metal fastener.
[0032] According to yet another aspect of the present technology,
there is provided a battery pack for a vehicle, comprising a first
module group comprising at least one battery module; a second
module group comprising at least one other battery module; and a
manually operable interrupter assembly selectively electrically
connecting the first module group to the second module group in
series, the interrupter assembly being adapted for opening and
closing a circuit connecting the first and second module
groups.
[0033] In some implementations of the present technology, a nominal
voltage of each of the first and second module groups individually
is less than a high voltage limit; and when the circuit is closed
by the interrupter assembly, the first and second module groups are
connected in series and a nominal voltage of the battery pack is
greater than the high voltage limit.
[0034] In some implementations of the present technology, the high
voltage limit is 60 Volts.
[0035] In some implementations of the present technology, when the
circuit is closed by the interrupter assembly, the nominal voltage
of the battery pack is 96 Volts; and when the circuit is opened by
the interrupter assembly, the nominal voltage of each of the first
and second module groups is 48 Volts.
[0036] In some implementations of the present technology, each
module group comprises at least two battery modules connected in
series.
[0037] In some implementations of the present technology, the first
module group is mounted to a first location in the vehicle; the
second module group is mounted to a second location in the vehicle;
and the first location and the second location are spaced
apart.
[0038] In some implementations of the present technology, each one
of the at least one battery module and the at least one other
battery module comprises a plurality of bricks, each brick
comprising a phase change material block; and a plurality of
battery cells disposed at least in part in the phase change
material block.
[0039] Implementations of the present technology each have at least
one of the above-mentioned object and/or aspects, but do not
necessarily have all of them. It should be understood that some
aspects of the present technology that have resulted from
attempting to attain the above-mentioned object may not satisfy
this object and/or may satisfy other objects not specifically
recited herein.
[0040] Additional and/or alternative features, aspects and
advantages of implementations of the present technology will become
apparent from the following description and the accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0041] For a better understanding of the present technology, as
well as other aspects and further features thereof, reference is
made to the following description which is to be used in
conjunction with the accompanying drawings, where:
[0042] FIG. 1 is a perspective view taken from a front, right side
of a battery pack;
[0043] FIG. 2 is a perspective view taken from a front, right side
of the battery pack of FIG. 1 mounted in the frame of a
vehicle;
[0044] FIG. 3 is a front elevation view of the battery pack of FIG.
1;
[0045] FIG. 4 is an exploded perspective view of a module of the
battery pack of FIG. 1;
[0046] FIG. 5 is an exploded perspective view of a brick of the
module of FIG. 4;
[0047] FIGS. 6a and 6b are perspective and front views,
respectively, of a PCM block of the brick of FIG. 4;
[0048] FIG. 7 is an exploded perspective view of portions of two
adjacent bricks of the module of FIG. 4;
[0049] FIGS. 8 and 9 are perspective views taken from opposite
sides of portions of the module of FIG. 4;
[0050] FIGS. 10 and 11 are top plan and perspective views
respectively of portions of the module of FIG. 4; and
[0051] FIGS. 12 and 13 are top plan and perspective views
respectively of portions of the module of FIG. 4.
DETAILED DESCRIPTION
[0052] With reference to FIGS. 1 to 3, a battery pack 10 includes
four battery modules 12a to 12d arranged vertically, one atop the
other. The four modules 12a to 12d of the pack 10 are mounted
within the frame 14 of a vehicle. The modules 12a to 12d are
connected in series via cables 16a to 16d, bus bars 18a and 18b,
and switch assembly 20, hereinafter referred to as an interrupter
assembly 20. The cable 16a connects the vehicle systems to a
negative terminal 22 of the module 12a, the bus bar 18a connects
the positive terminal 24 of the module 12a to the negative terminal
22 of the module 12b, the cable 16b connects the positive terminal
24 of the module 12b to a first terminal 26 of the interrupter
assembly 20, the cable 16c connects a second terminal 28 of the
interrupter assembly 20 to the negative terminal 22 of the module
12c, the bus bar 18b connects the positive terminal 24 of the
module 12c to the negative terminal 22 of the module 12d, and the
cable 16d connects the positive terminal 24 of the module 12d to
the vehicle systems. The vehicle systems to which the cables 16a
and 16d connect can include, but are not limited to, a motor
controller, a charger and a DC/DC converter.
[0053] The frame 14 of FIG. 2 is that of a three-wheeled, straddle
seat road vehicle, also called a roadster. It is contemplated that
the vehicle could be, inter alia, a two- or four-wheeled on-road
vehicle, an off-road vehicle such as an all-terrain vehicle, a
side-by-side vehicle or a snowmobile, or a waterborne vessel such
as a personal watercraft or boat. It is contemplated that the pack
10 could include more or less modules than the four modules 12a to
12d illustrated. As will be discussed in more detail herein below,
each module has a nominal voltage of 24V and the pack 10 has a
nominal voltage of 96V. Providing two modules 12 in series would
provide a pack with a nominal voltage of 48V. It is also
contemplated that the modules 12a to 12d could be arranged other
than vertically. For example, they could be arranged in two stacks
of two modules 12a to 12d. It is contemplated that the modules
could be mounted within a vehicle at different locations, i.e. not
all adjacent one another.
[0054] The interrupter assembly 20 is electrically connected
between the modules 12b and 12c, thereby enabling the user to
manually open or close the circuit between these two modules.
During operation of the vehicle, the interrupter assembly 20 is
closed, thereby completing the circuit between the four modules 12a
to 12d. When not in operation, such as during storage or
maintenance, the interrupter assembly 20 can be opened, thereby
dividing the pack 10 into two halves, each with a maximum voltage
of 48 volts. According to the SAE Surface Vehicle Standard J1673
MAR2012, vehicle systems that contain a circuit operating above 50
volts (DC) are considered "high voltage" and surpass a high voltage
limit. Similar technical standards and/or regulations exist for
other regions, such as the European Union's Directive 2006/95/EC
which pertains to circuits over 75 volts (DC) and the United
Nations' UNECE R100 which pertains to circuits over 60 volts (DC).
As such, a vehicle comprising the battery pack 10 can be rendered
"low voltage" when not in use. It will be appreciated that this can
be advantageous for repairs, maintenance and the like.
[0055] FIG. 4 shows an exploded view of an exemplary module 12
(i.e. the modules 12a, 12b, 12c, and 12d have a similar
construction). For clarity, the module 12 has been inverted, that
is to say its bottom side is facing up. The module 12 and the
components thereof will hereinafter be shown in this orientation
and spatial references such as "above" and "below" will, unless
otherwise specified, be used in this frame of reference.
[0056] The module 12 comprises a plurality of battery sub-modules
40, hereinafter referred to as bricks 40, a fuse 42, a current
sensor 44 and a battery management system (BMS) 46, all housed
within a housing 48. The housing 48 includes a housing body 50
which forms a cavity in which the bricks 40 are received. The
housing 48 further comprises a lid 52 which is secured to the
housing body 50 by a plurality of bolts 54. A gasket 56 is
positioned between the body 50 and the lid 52 in order to seal the
cavity within the housing 48. A communication terminal 58 and the
negative and positive terminals 22 and 24 are provided on the
housing 48 so as to be accessible from outside the module 12. In
one implementation, the body 50 and lid 52 are made of aluminum,
although it is contemplated that other materials are possible.
[0057] Each brick 40 comprises a plurality of battery cells 60
surrounded by a PCM block 62 made of a PCM material, as will be
described in further detail herein below with reference to FIG. 5.
During assembly, a layer of thermally conductive filler 64 is
applied between the lid 52 and the plurality of bricks 40 so as to
increase thermal conduction therebetween. In the present
implementation, the thermally conductive filler 64 is thermal
silicone (also called thermal grease) which is applied during
assembly in the form of a highly viscous liquid and hardens
thereafter, filling any gaps between the bricks 40 and the lid 52.
It is contemplated that various types of thermal silicone, or other
highly viscous thermally conductive filler materials, could be used
in the present application. The application of a suitable layer of
thermal silicone during assembly can help accommodate for any
variations in the dimensions of the bricks 40 or the housing 48,
thereby allowing for greater tolerances while maximizing thermal
conduction between the bricks 40 and the housing 48.
[0058] Another layer of thermal silicone 66 is applied between the
bricks 40 and the wall of the body 50 opposite the lid 52, which is
similarly intended to increase thermal conduction between the
bricks 40 and the housing 48. In use, heat generated within the
cells 60 of each brick 40 can be dissipated through the thermal
silicone 64 and 66, and through the metallic housing 48 to the
environment.
[0059] It is contemplated that an active heat exchange system, such
as liquid cooling or forced air, could be added to the structure
illustrated herein in order to further aid in cooling the cells 60.
In particular, it is contemplated that the lid 52, or another part
of the housing 48, could be provided with a liquid heat-exchanger
in order to draw more heat away from the module 12. Alternatively,
fans could be provided proximate the lid 52, or another part of the
housing 48, to force cooling air across the module 12. The housing
48 could also be provided with heat-exchange fins to encourage
cooling. It is also contemplated that the lid 52, or other part of
the housing 48, could be provided with a heating element for
ensuring the cells 48 are warm enough when operating in a cold
environment.
[0060] In order to ease assembly, the cavity formed within the body
50 has a tapered shape and four foam wedges 68a to 68d are
positioned between the lateral walls of the body 50 and the bricks
40. The wedges 68a to 68d can be formed, inter alia, from neoprene,
plastic, polystyrene foam or the like, either alone or in
combination. Additional layers of thermal silicone or another
thermally conductive filler could be used in place of the wedges
68a to 68d.
[0061] FIG. 5 shows an exploded view of an exemplary brick 40. As
mentioned above, the bricks 40 each comprise a plurality of battery
cells 60 surrounded by the PCM block 62. More particularly, each
brick 40 comprises a total of 45 cells 60. The cells 60 are
cylindrical in shape with negative and positive terminals 70 and 71
at either extremity. It is contemplated that the cells 60 are 18650
or 26650 cells, although other sizes could also be used. It is
contemplated that the cells 60 could be other than cylindrically
shaped. It is also contemplated that more or less cells 60 could be
provided per brick 40. In particular, it is contemplated that
between 10 and 60 cells per brick 40 could be provided.
[0062] The PCM block 62 comprises a plurality of slots 72, one for
each of the plurality cells 60. Each slot 72 is sized to correspond
to the length of a corresponding cell 60. The thickness of the PCM
block 62 equals that of the cells 60 and each slot 72 extends
through the entire thickness of the PCM block 62. When assembled,
the negative and positive terminals 70 and 71 of each cell 60 are
flush with the faces of the PCM block 62 at the extremities of
their respective slots 62. It is also contemplated that the
thickness of the PCM block 62 could be less than the length of the
cells 60, such that their negative and positive terminals 70 and 71
protrude beyond the PCM block 62, or that the thickness of the PCM
block 62 could be greater than the length of the cells 60.
[0063] The diameter of each slot 72 is sized to correspond with the
diameter of the cells 60. In the implementation illustrated herein,
the slots 72 are sized so as to ensure as much contact between the
cells 60 along their lateral sides as possible in order to maximize
the transmission of heat therebetween, although other arrangements
are possible. The cells 60 are oriented such that all of the
negative terminals 70 are on one side of the PCM block 62 and all
the positive terminals 71 are on the other. Referring to the frame
of reference of FIG. 5, the negative terminals 70 face rearward and
the positive terminals 71 face forward.
[0064] Each brick 40 comprises first, second and third electrical
insulators 74, 76 and 78 which surround the PCM block 62. When
assembled, the outwardly-facing surfaces of the PCM block 62, i.e.
those which are not facing and/or in contact with the lateral sides
of the cells 60, are covered by a combination of the first, second
and third electrical insulators 74, 76 and 78.
[0065] The first electrical insulator 74 covers the rearward-facing
side of the PCM block 62 and comprises openings 80 for each
negative terminal 70. The first electrical insulator 74 also
extends halfway across the top, bottom, left and right sides of the
PCM block 62, from the rearward-facing side towards the
forward-facing side.
[0066] The second electrical insulator 76 is a mirror image of the
first electrical insulator 74. It covers the forward-facing side of
the PCM block 62 and comprises openings 82 for each positive
terminal 71. The second electrical insulator 76 also extends
halfway across the top, bottom, left and right sides of the PCM
block 62, from the forward-facing side towards the rearward-facing
side. When assembled, the first and second electrical insulators
each cover half of the outwardly-facing surfaces of the PCM block
62.
[0067] The third electrical insulator 78 extends around the top,
bottom, left and right faces of the PCM block 62. The third
electrical insulator 78 covers the seam between the first and
second electrical insulators 74 and 76. With the first, second and
third electrical insulators in position around the PCM block 62 and
the cells 60, only the negative and positive terminals 70 and 71
are uncovered.
[0068] Each brick 40 further comprises a negative current collector
84 which is positioned adjacent and across the first electrical
insulator 74. The first electrical insulator 74 separates the
negative current collector 84 from the rearward-facing side of the
PCM block 62, but the openings 80 allow contact between the
negative current collector 84 and the negative terminals 70 of each
cell 60. To ensure a conductive connection, the negative current
collector 84 and the negative terminal 70 of each cell 60 are
ultrasonically welded to each other, although it is contemplated
that other means of ensuring a conductive connection could be used,
such as laser welding or friction welding.
[0069] Each brick 40 further comprises a positive current collector
88 which is positioned adjacent and across the second electrical
insulator 76. The second electrical insulator 76 separates the
positive current collector 88 from the forward-facing side of the
PCM block 62, but the openings 82 allow contact between the
positive current collector 88 and the positive terminals 71 of each
cell 60. To ensure a conductive connection, the positive current
collector 88 and the positive terminals 71 of each cell are
friction welded to each other, although it is contemplated that
other means of ensuring a conductive connection could be used.
[0070] The negative and positive current collectors 84 and 88 are
formed from sheets of conductive material, such as nickel, copper
or the like, either alone or in combination. The negative and
positive current collectors 84 and 88 of the current implementation
each comprise a sheet of nickel welded to a sheet of copper. Both
sheets are 10 thousandths of an inch (0.254 mm) thick, giving a
total thickness of 20 thousandths of an inch (0.508 mm). The
negative current collector 84 comprises a plurality of contact
portions 86, one for every opening 80. When assembled, each contact
portion 86 is positioned opposite a respective opening and a
respective negative terminal 70. The contact portions 86 each have
a forked shape with two branches that are friction welded to the
corresponding negative terminal 70 and a thinner base that connects
the welded branches to the remainder of the negative current
collector 84.
[0071] The positive current collector 88 comprises a plurality of
contact portions 90, one for every opening 82. When assembled, each
contact portion 90 is positioned opposite a respective positive
terminal 71. The contact portions 90 each comprise two tabs formed
by H-shaped cut-outs in the positive current collector 88. The two
tabs are each friction welded to the corresponding positive
terminal 71.
[0072] Each brick 40 further comprises fourth and fifth electrical
insulators 92 and 94 which form its rearward-most and forward-most
layers respectively. The fourth and fifth electrical insulators 92
and 94 each cover a substantial portion of the rearward-and
forward-facing faces of the negative and positive current
collectors 84 and 88, respectively. The first, second, third,
fourth and fifth electrical insulators 74, 76, 78, 92 and 94 of the
present implementation are formed from sheets of electrical
insulation paper, such as ThermaVolt.TM. manufactured by 3M.TM.,
which is held in place by an adhesive backing.
[0073] The cells 60 are arranged within the PCM block 62 in an
alternating pattern that forms a plurality of channels 96 across
the top of the PCM block 62. The first, second, third, fourth and
fifth electrical insulators 74, 76, 78, 92 and 94 comprise
corresponding shapes along their upper sides/edges. The present
implementation of the PCM block 62 and the 45 slots 72 that receive
the 45 cells 60 are shown in more detail in FIGS. 6a and 6b. The
slots 72 are aligned in nine columns 98a to 98i of five slots 72
each, i.e. the longitudinal axis 100a of a given slot 72 will be
aligned with the longitudinal axes 100b and 100c of the slots 72
above and below it. Each column 98a to 98i is offset vertically
from the adjacent column(s) to the left and/or to the right of it,
i.e. the longitudinal axis 100a of the slot 72 will not be aligned
with longitudinal axes 100e to 100h of the slots 72 to the left and
to the right of it. As such, a given cell 60 will have another cell
60 immediately above and/or below it at the same horizontal
position across the width of the PCM block 62 (thereby forming the
columns 98a to 98i), but the cells 60 to the left and/or right of
it will not be at the same vertical position across the height of
the PCM block 62. In the present implementation, the longitudinal
axes 100e to 100h are vertically offset from the longitudinal axis
100a (either upwards or downwards) by half the distance between the
longitudinal axes 100a and the longitudinal axes 100b and 100c
above and below it. This alternating pattern permits a tighter
packing of the cells 60 within the PCM block 62 and a reduction in
the width of the PCM block 62. Staggering the cells 60 in this way
also allows the formation of channels 96a to 96e along the top side
of the PCM block 62 beside and between the second, fourth, sixth
and eighth columns 98b, 98d, 98f and 98h.
[0074] It is contemplated that channels similar to those shown in
FIGS. 6a and 6b could be provided along the bottom side of the PCM
block 62 either in addition to or in place of the channels 96a to
96e. While the present implementation comprises an alternating
pattern of columns, it is contemplated that the cells 60 and slots
72 could similarly be arranged in an alternating pattern of rows
that form channels along the left and/or right sides of the PCM
block 62.
[0075] The modules 12 shown in the present implementation each
comprise seven bricks 40, although it is contemplated that more or
less bricks 40 could be provided per module 12. It is contemplated
that between six and 20 bricks 40 could be provided. The cells 60
of the brick 40 are connected in parallel via the negative and
positive current collectors 84 and 88 which connect the negative
and positive terminals 70 and 71, respectively, of each cell. The
seven bricks 40 of each module 12 are connected in series, that is
to say the negative current collector 84 of one brick 40 is
connected to the positive current collector 88 of an adjacent brick
40 such that the voltage of the module 12 is the sum of the
voltages of the bricks 40 therein. As discussed above, the four
modules 12 are also connected in series.
[0076] With reference to FIG. 7, two exemplary bricks 40a and 40b
are shown in a partially exploded state to illustrate the
connection therebetween. For clarity, the elements of the left
brick 40a (with respect to the frame of reference of FIG. 7) are
labeled with the suffix "a" while, similarly, the elements of the
adjacent right brick 40b are labeled with the suffix "b". When
assembled, the fifth electrical insulator 94a of the left brick 40a
is adjacent the fourth electrical insulator 92b of the right brick
40b. The presence of the electrical insulators 94a and 92b separate
the negative and positive current collectors 88a and 84b, except
along their upper edges where they will be connected as described
below. The electrical insulators 94a and 92b prevent the contact
portions 90a of the positive current collector 88a from coming into
contact with the contact portions 86b of the negative current
collector 84b.
[0077] The positive and negative current collectors 88a and 84b of
the adjacent bricks 40a and 40b are electrically connected by a
plurality of connectors 104 which are embodied herein by bolts 106,
nuts 108 and washers 110. Each bolt 106 passes through a hole 112a
in the positive current collector 88a and a corresponding hole 114b
in the negative current collector 84b. The washers 110 sandwich the
portion of the negative and positive current collectors 88a and 84b
around the holes 112a and 114b, ensuring a contact therebetween. In
addition, the bolts 106, nuts 108 and washers 110 are metallic and
can conduct current between the bricks 40a and 40b. The holes 112a
and 114b are located along the top edge of the positive and
negative current collectors 88a and 84b, respectively, such that
the bolts 106, the nuts 108 and the washers 110 are located in the
channels 96. In the present implementation, there are four pairs of
holes 112a and 114b, each within a channel 96. It will be
appreciated that various alternative ways of connecting negative
and positive current collectors 88a and 84b, such as welding,
rivets, clamps, clips and the like. It is also contemplated that
adjacent current collectors 88a and 84b could be formed from a
single conductive sheet folded in half with one or both of the
electrical insulators 94a and 92b therebetween.
[0078] FIGS. 8 and 9 show seven bricks 40a to 40g connected in
series between the positive and negative terminals 24 and 22. The
charge path (indicated in with arrows and representing a positive
current direction as seen by the BMS 46) begins at the positive
terminal 24 which his connected to the first brick 40a via a first
bus bar 116. The first bus bar 116 is connected to the positive
current collector 88 of the first brick 40a via connectors 104
which engage the holes 112 of the first brick 40a and a
corresponding set of holes (not shown) in the bus bar 116 in a
manner similar to that described above. The negative current
collector 84 of the first brick 40a is connected to the positive
current collector 88 of the second brick 40b, the negative current
collector 84 of the second brick 40b is connected to the positive
current collector 88 of the third brick 40c, and the negative
current collector 84 of the third brick 40c is connected to a
second bus bar 118. These connections are all made via connectors
104 which engage holes 112 and/or 114.
[0079] The charge path continues through the second bus bar 118 to
the positive current collector 88 of the fourth brick 40d. The
negative current collector 84 of the fourth brick 40d is connected
to the positive current collector 88 of the fifth brick 40e, the
negative current collector 84 of the fifth brick 40e is connected
to the positive current collector 88 of the sixth brick 40f, the
negative current collector 84 of the sixth brick 40f is connected
to the positive current collector 88 of the seventh brick 40g, and
the negative current collector 84 of the seventh brick 40g is
connected to a third bus bar 120. Again, these connections are all
made via connectors 104 which engage holes 112 and/or 114.
[0080] The charge path continues from the third bus bar 120 to the
fuse 42, the current sensor 44 and ends at the negative terminal
22. The internal components of the negative and positive terminals
22 and 24, the bus bar 116, the current sensor 44, the fuse 42 and
the BMS 46 (not shown in FIGS. 8 and 9) occupy a space roughly the
size of a brick 40. The present architecture of seven bricks 40 and
the accompanying electrical and electronic components form a
substantially U-shaped package within the module 12. It is
contemplated that the bricks 40 could be arranged and connected in
other formations, such as in a single line, in an S shape or and M
shape.
[0081] The BMS 46 of each module 12 monitors and logs the
temperature and voltage of each brick 40, and the current through
the module 12 (via the sensor 44) to ensure these parameters stay
within their operational limits. The BMS 46 can register fault
and/or error codes when those limits are exceeded. The BMS 46 also
calculates the state of charge and state of health of the module 12
and bricks 40. Each BMS 46 outputs this information via the
communication terminal 58 to the vehicle's CAN-bus network to a
vehicle control module (not shown) that also communicates with the
vehicle's motor controller(s).
[0082] The cells 60 are lithium-ion rechargeable cells. More
particularly, they are lithium-nickel-manganese-cobalt cells (NMC),
although other types of cells are contemplated. For example, it is
contemplated that the cells 60 could be
lithium-nickel-cobalt-aluminum (NCA), lithium-manganese-spinel
(LMO), lithium-titanate (LTO), lithium-iron-phosphate (LFP) cells
or lithium sulfur (Li--S). The nominal voltage of each NMC cell 60
is 3.65V. Accordingly, the voltage of each brick 40 is 3.65V, the
voltage of each module 12 comprising seven bricks 40 is 25.55V and
the voltage of each pack 10 comprising four modules 12 is 102.2V.
Such a module is said to have a nominal voltage of 24V and such a
pack 10 is considered to have a nominal voltage of 96V. In the
present implementation, each module 12 has 2.5 kwh at 24V resulting
in 10 kwh at 96V with 30 kW continuous power and 55 kW peak power
for the pack 10. It will be appreciated that NCA cells have an
equivalent voltage to NMC cells and as such the resultant voltages
of the bricks 40, modules 12 and packs 10 comprising NCA cells
would be equivalent to those of the NMC cells 60. It is
contemplated that a 120V pack 10 comprising Li--S cells having a
nominal voltage of 2.2V could also be provided.
[0083] The PCM block 62 acts as a heat sink during discharge of the
cells 60. Preventing the cells 60 from getting too hot during
discharge is important to both prevent thermal runaway and protect
the cells from damage which could reduce their performance and
lifespan, as is maintaining an even temperature across all the
cells 60 of a given brick 40. It is contemplated that the PCM block
62 could be formed from a wax and graphite matrix PCM material,
such as the Phase Change Composite (PCC.TM.) material manufactured
by Allcell. During discharge, as the cells 60 heat up, the PCM
block 62 thermally conducts that heat to spread it out evenly
across the brick 40. As the temperature of the brick 40, or any
parts thereof, approaches the melting point of the PCM block 62
(T.sub.melt), heat energy begins to be absorbed by the melting
(i.e. phase change) process. The proportion of the PCM block 62
that has melted at a given moment is referred to as the liquid
fraction. When the liquid fraction has reached 100%, every part of
the brick 40 will have reached T.sub.melt and the PCM material can
absorb no further heat. Once discharge has stopped, the PCM block
62 will release the heat absorbed during discharge to the
surrounding environment and the liquid fraction will eventually
return to 0%.
[0084] Different PCM materials will have different T.sub.melt, for
example PCM materials are available that have 43.degree. C.,
48.degree. C. or 55.degree. C. The PCM block 62 is selected so that
the T.sub.melt is below a maximum desired operating temperature
during discharge (T.sub.max-discharge) in order to help prevent
thermal runaway and damage to the cells 60 and above the maximum
ambient temperature of operation of the battery pack 10. For
example, in the present implementation the T.sub.max-discharge of
the cells 60 is 60.degree. C. The PCM block 62 is therefore
selected to have a T.sub.melt lower than 60.degree. C. It is common
to select PCM material that has the highest T.sub.melt lower than
the T.sub.max-discharge.
[0085] However, the cells 60 also have a maximum temperature at
which they can be charged (T.sub.max-charge). T.sub.max-charge is
typically less than T.sub.max-discharge. For example, the cells 60
of the present implementation have a T.sub.max-charge of 45.degree.
C. Cells 60 that have reached a temperature above T.sub.max-charge
during operation (i.e. discharge) cannot be charged until the pack
10 has cooled to below T.sub.max-charge. A conventional battery
pack with cells having a T.sub.max-discharge of 60.degree. C. and a
PCM material having a T.sub.melt of 55.degree. C. that undergoes
heavy usage and discharge of the cells that necessitates absorption
by the PCM material will not be able to be recharged immediately
after usage since the battery pack must cool to 45.degree. C.
(T.sub.max-charge). The PCM block 62 of the present implementation
therefore comprises a PCM material with a T.sub.melt lower than the
T.sub.max-charge in order to ensure that the cells 60 will be ready
to be recharged immediately after they are discharged. This can be
especially advantageous in implementations where quick recharging
is desirable.
[0086] As mentioned above, the BMS 46 monitors the voltage of each
brick 40. With reference to FIGS. 10 and 11, a module 12 is shown
with a voltage monitoring assembly 122 which links the BMS 46 to
each of the bricks 40a to 40g. The voltage monitoring assembly 112
comprises a wire harness 124 comprising eight wires 126a to 126h
which connect the BMS 46 to points before and after each brick 40a
to 40g. A first extremity of the first wire 126a is connected to
the positive current collector 88 of the first brick 40a. A first
extremity of the second wire 126b is connected to the negative
current collector 84 of the first brick 40a and the positive
current collector 88 of the second brick 40b. A first extremity of
the third wire 126c is connected to the negative current collector
84 of the second brick 40b and the positive current collector 88 of
the third brick 40c. A first extremity of the fourth wire 126d is
connected to the positive current collector 88 of the fourth brick
40d and the second bus bar 118. A first extremity of the fifth wire
126e is connected to the negative current collector 84 of the
fourth brick 40d and the positive current collector 88 of the fifth
brick 40e. A first extremity of the sixth wire 126f is connected to
the negative current collector 84 of the fifth brick 40e and the
positive current collector 88 of the sixth brick 40f A first
extremity of the seventh wire 126g is connected to the negative
current collector 84 of the sixth brick 40f and the positive
current collector 88 of the seventh brick 40g. A first extremity of
the eighth wire 126h is connected to the negative current collector
84 of the seventh brick 40g and the third bus bar 120.
[0087] The first extremities of each wire 126a to 126h are
electrically connected to respective positive and negative current
collectors 88 and 84 via connectors 104 in the manner described
above. The harness 124 extends along a central channel 128 formed
along the center of the module by the innermost channels 96 of the
bricks 40a to 40g. The connections between the first extremities of
the wires 126a to 126h and the bricks 40a to 40g are made within
the central channel 128.
[0088] Each wire 126a to 126h comprises a second extremity opposite
its respective first extremity that is connected to a voltage
monitoring assembly connector 130 that plugs into the BMS 46. The
BMS 46 is therefore provided with the voltage before and after each
brick 46a to 46g, thereby enabling monitoring of the voltage of
each brick 46a to 46g.
[0089] The harness 124 further comprises a first power wire 132a
having a first extremity connected to a BMS power connector 134 and
a second extremity connected to the positive current collector 88
of the first brick 40a. The voltage monitoring assembly 122 further
comprises a second power wire 132b having a first extremity
connected to the BMS power connector 134 and a second extremity
connected to the negative current collector 84 of the seventh brick
40g and the third bus bar 120. The first and second power wires
132a and 132b provide the 24V of the module 12 to power the BMS
46.
[0090] As mentioned above, the BMS 46 also monitors the temperature
of each brick 40a to 40g. With reference to FIGS. 12 and 13, a
module 12 is shown with a temperature monitoring assembly 136. The
assembly 136 comprises a wire harness 138 comprising eight wires
140a to 140h which connect the BMS 46 to points across the module
12. The first extremity of each wire 140a to 140h is connected to a
thermistor 142. The second extremity of each wire 140a to 140h is
connected to a temperature monitoring assembly connector 144 that
plugs into the BMS 46.
[0091] The thermistor 142 of the first wire 140a is connected, via
a connector 104, to the first bus bar 116. The thermistors of the
wires 140b to 140h are each in contact with a respective one of the
PCM blocks 62 of the bricks 40a to 40g. Specifically, these
thermistors 142 are passed through an opening in respective
electrical insulators 74, 76 and/or 78 so as to contact respective
PCM blocks 62 directly. The thermistors 142 can be glued or
otherwise fixed in position. Like the wire harness 124 of the
voltage monitoring assembly 122, the wires 140a to 140h of the wire
harness 138 extend from the connector 144 through the channel 128
formed by the innermost channels 96 of the bricks 40a to 40g.
[0092] Modifications and improvements to the above-described
implementations of the present technology may become apparent to
those skilled in the art. The foregoing description is intended to
be exemplary rather than limiting.
* * * * *