U.S. patent application number 15/693023 was filed with the patent office on 2017-12-21 for energy storage system with heat pipe thermal management.
This patent application is currently assigned to Tesla, Inc.. The applicant listed for this patent is Tesla, Inc.. Invention is credited to Carlos Mario Aguirre, Augusto E. Barton, Nathan Chidiac, Hae-Won Choi, Orion A. King, Robert C. Lane, Mark Riegel, David Rosenberg, Ernest Villanueva, Jon Wagner, Jeff Weintraub.
Application Number | 20170365895 15/693023 |
Document ID | / |
Family ID | 53883114 |
Filed Date | 2017-12-21 |
United States Patent
Application |
20170365895 |
Kind Code |
A1 |
Lane; Robert C. ; et
al. |
December 21, 2017 |
ENERGY STORAGE SYSTEM WITH HEAT PIPE THERMAL MANAGEMENT
Abstract
An energy storage system includes multiple cells, a heat pipe, a
first heat transfer channel, and a second heat transfer channel.
Each cell has a first end with anode and cathode terminals and a
second end opposite the first end with the multiple cells arranged
so that the second ends are aligned. The heat pipe has a U-shape
and includes an evaporation portion having a flat evaporation
surface facing the second ends of the multiple cells, a first
condensation portion oriented substantially perpendicular to the
evaporation portion, and a second condensation portion oriented
substantially perpendicular to the evaporation portion. The first
condensation portion is at a first end of the evaporation portion
and the second condensation portion is at a second end of the
evaporation portion. The first heat transfer channel abuts the
first condensation portion and the second heat transfer channel
abuts the second condensation portion.
Inventors: |
Lane; Robert C.; (Redwood
City, CA) ; Choi; Hae-Won; (Alameda, CA) ;
Weintraub; Jeff; (San Carlos, CA) ; Aguirre; Carlos
Mario; (Cupertino, CA) ; Riegel; Mark; (Los
Gatos, CA) ; King; Orion A.; (Menlo Park, CA)
; Chidiac; Nathan; (Los Altos, CA) ; Wagner;
Jon; (Belmont, CA) ; Barton; Augusto E.; (Palo
Alto, CA) ; Villanueva; Ernest; (San Francisco,
CA) ; Rosenberg; David; (Lone Rock, WI) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Tesla, Inc. |
Palo Alto |
CA |
US |
|
|
Assignee: |
Tesla, Inc.
Palo Alto
CA
|
Family ID: |
53883114 |
Appl. No.: |
15/693023 |
Filed: |
August 31, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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14189219 |
Feb 25, 2014 |
9761919 |
|
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15693023 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01M 10/625 20150401;
Y02T 10/70 20130101; H01M 2/206 20130101; H01M 10/6552 20150401;
H01M 2220/20 20130101; H01M 10/643 20150401; H01M 10/653 20150401;
Y02E 60/10 20130101; H01M 10/6556 20150401 |
International
Class: |
H01M 10/6556 20140101
H01M010/6556; H01M 10/643 20140101 H01M010/643; H01M 10/625
20140101 H01M010/625; H01M 10/653 20140101 H01M010/653; H01M
10/6552 20140101 H01M010/6552; H01M 2/20 20060101 H01M002/20 |
Claims
1. An energy storage system comprising: multiple cells, each cell
having a first end with anode and cathode terminals, and a second
end opposite the first end, the multiple cells arranged so that the
second ends are aligned; a heat pipe having a U-shape, the heat
pipe including an evaporation portion having a flat evaporation
surface thermally coupled to the second ends of the multiple cells,
a first condensation portion oriented substantially perpendicular
to the evaporation portion, and a second condensation portion
oriented substantially perpendicular to the evaporation portion,
the first condensation portion at a first end of the evaporation
portion, and the second condensation portion at a second end of the
evaporation portion; a first heat transfer channel abutting the
first condensation portion, the first heat transfer channel
configured to reject thermal energy from, or bring thermal energy
to, the first condensation portion; and a second heat transfer
channel abutting the second condensation portion, the second heat
transfer channel configured to reject thermal energy from, or bring
thermal energy to, the second condensation portion.
2. The energy storage system of claim 1, further comprising
electrical connections interconnecting the multiple cells.
3. The energy storage system of claim 1, further comprising at
least one clamshell that holds the multiple cells in place.
4. The energy storage system of claim 1, further comprising an
electric insulator layer disposed between the flat evaporation
surface and the multiple cells, the electrical insulator being
thermally conductive.
5. The energy storage system of claim 1, further comprising a
phase-change fluid within the heat pipe.
6. The energy storage system of claim 5, further comprising at
least one interior channel within the heat pipe that aids flow of
the phase-change fluid.
7. The energy storage system of claim 1, further comprising: a
first manifold coupled to first ends of the first and second heat
transfer channels; and a second manifold coupled to second ends of
the first and second heat transfer channels to enable flow of
coolant from the first manifold to the second manifold through the
first and second heat transfer channels.
8. The energy storage system of claim 1, wherein the multiple cells
are positioned so that the second ends are aligned with a vertical
plane and the flat evaporation surface extends along the vertical
plane.
9. The energy storage system of claim 1, wherein the multiple cells
have cylinder shapes that are vertically oriented with respect to
the flat evaporation surface.
10. An energy storage system comprising: multiple cells, each
cylindrically shaped cell having a first end with anode and cathode
terminals, and a second end opposite the first end, the multiple
cells arranged so that the second ends are aligned; a flexible
printed circuit that overlies and interconnects electrical
terminals of the multiple cells; a heat pipe having a U-shape, the
heat pipe including an evaporation portion having a flat
evaporation surface thermally coupled to the second ends of the
multiple cells, a first condensation portion oriented substantially
perpendicular to the evaporation portion, and a second condensation
portion oriented substantially perpendicular to the evaporation
portion, the first condensation portion at a first end of the
evaporation portion, and the second condensation portion at a
second end of the evaporation portion, wherein the multiple cells
are vertically oriented with respect to the flat evaporation
surface; an electric insulator layer disposed between the flat
evaporation surface and the multiple cells, the electrical
insulator being thermally conductive; a first heat transfer channel
abutting the first condensation portion, the first heat transfer
channel configured to reject thermal energy from, or bring thermal
energy to, the first condensation portion; and a second heat
transfer channel abutting the second condensation portion, the
second heat transfer channel configured to reject thermal energy
from, or bring thermal energy to, the second condensation
portion.
11. The energy storage system of claim 10, further comprising a
phase-change fluid within the heat pipe.
12. The energy storage system of claim 11, further comprising at
least one interior channel within the heat pipe that aids flow of
the phase-change fluid.
13. The energy storage system of claim 10, further comprising: a
first manifold coupled to first ends of the first and second heat
transfer channels; and a second manifold coupled to second ends of
the first and second heat transfer channels to enable flow of
coolant from the first manifold to the second manifold through the
first and second heat transfer channels.
14. The energy storage system of claim 10, wherein the multiple
cells have cylinder shapes and are vertically oriented with respect
to the flat evaporation surface.
15. An energy storage system for containing multiple cells, each
cylindrical shaped cell having a first end with anode and cathode
terminals, and a second end opposite the first end, the multiple
cells arranged so that the second ends are aligned, the energy
storage system comprising: a heat pipe having a U-shape, the heat
pipe including an evaporation portion having a flat evaporation
surface thermally coupled to the second ends of the multiple cells,
a first condensation portion oriented substantially perpendicular
to the evaporation portion, and a second condensation portion
oriented substantially perpendicular to the evaporation portion,
the first condensation portion at a first end of the evaporation
portion, and the second condensation portion at a second end of the
evaporation portion; a first heat transfer channel abutting the
first condensation portion, the first heat transfer channel
configured to reject thermal energy from, or bring thermal energy
to, the first condensation portion; and a second heat transfer
channel abutting the second condensation portion, the second heat
transfer channel configured to reject thermal energy from, or bring
thermal energy to, the second condensation portion.
16. The energy storage system of claim 15, further comprising
electrical connections interconnecting the multiple cells.
17. The energy storage system of claim 15, further comprising an
electric insulator layer disposed between the flat evaporation
surface and the multiple cells, the electrical insulator being
thermally conductive.
18. The energy storage system of claim 15, further comprising a
phase-change fluid within the heat pipe.
19. The energy storage system of claim 15, further comprising: a
first manifold coupled to first ends of the first and second heat
transfer channels; and a second manifold coupled to second ends of
the first and second heat transfer channels to enable flow of
coolant from the first manifold to the second manifold through the
first and second heat transfer channels.
20. The energy storage system of claim 15, wherein the multiple
cells are positioned so that the second ends are aligned with a
vertical plane and the flat evaporation surface extends along the
vertical plane.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] The present U.S. Utility patent application claims priority
pursuant to 35 U.S.C. .sctn.120 as a continuation of U.S. Utility
application Ser. No. 14/189,219 entitled "ENERGY STORAGE SYSTEM
WITH HEAT PIPE THERMAL MANAGEMENT", filed 25 Feb. 2014, which is
hereby incorporated herein by reference in its entirety and made
part of the present U.S. Utility patent application for all
purposes.
BACKGROUND
[0002] Energy storage systems are used in a variety of contexts.
For example, an electric vehicle can have a number of individual
energy storage units (e.g., lithium-ion cells) stored inside a
compartment, and this system is often referred to as a battery
pack. Cells and other storage units generate heat during operation,
such as during the charging process and when the cells are used to
deliver energy, for example to the propulsion/traction system of
the vehicle.
[0003] One cooling approach currently being used involves
lithium-ion cells that are electrically connected by an anode
terminal at the bottom of the cell, and a cathode terminal on top
of the cell. These cells are arranged to all have the same
orientation (e.g., "standing up") with some spacing provided
between all adjacent cells. The spacing facilitates a cooling
conduit to run between the cells and be in contact with at least a
portion of the outer surface of each cell. The cooling conduit has
a coolant flowing through it, which removes thermal energy from
inside the battery pack to some location on the outside, where heat
can be safely dissipated. In order to provide a safe coolant flow,
one must provide fluid connections into and out of the battery
package, and the coolant path inside the battery pack must be
reliable and have enough capacity.
BRIEF DESCRIPTION OF DRAWINGS
[0004] FIG. 1 shows an example of an assembly that is part of an
energy storage system.
[0005] FIG. 2 shows an example of an energy storage system with
heat pipes that have an L-shape.
[0006] FIG. 3 shows another example of an energy storage system
with heat pipes that have an L-shape.
[0007] FIG. 4 shows an example of an energy storage system with
heat pipes that have a U-shape.
[0008] FIG. 5 shows another example of an energy storage system
with heat pipes that have a U-shape.
[0009] FIG. 6 shows another example of an energy storage system
with one or more heat pipes that have a U-shape, also including
coolant tubes.
[0010] FIG. 7 shows an example of an energy storage system with
linear heat pipes.
[0011] FIG. 8 shows another example of an energy storage system
with the linear heat pipes from FIG. 7.
[0012] FIG. 9 shows an example of an energy storage system where
heat pipes have a deformation corresponding to a cross section
profile of a heat transfer channel.
[0013] FIG. 10 shows another example of an energy storage system
with heat pipes having a U-shape, with thermal tubes on top and
bottom.
[0014] FIG. 11 shows another example of an energy storage system
with heat pipes having a U-shape, with thermal tubes extending
between manifolds positioned at shorter sides of the system.
[0015] FIG. 11A is a cross section of the energy storage system in
FIG. 11.
[0016] FIG. 12 shows another example of an energy storage system
with heat pipes having a U-shape, with thermal tubes extending
between manifolds positioned at longer sides of the system.
[0017] FIG. 12A is a cross section of the energy storage system in
FIG. 12.
DETAILED DESCRIPTION
[0018] This document describes examples of systems and techniques
that provide face cooling of cells or other energy storage units by
way of heat pipes. This can provide useful advantages, such as: The
need for internal fluid connections in a battery pack can be
eliminated, thereby avoiding leakage; a closed loop cooling system
can be provided that reduces pressure drop losses with regard to an
overall cooling system (e.g., in a vehicle); external cooling tube
assemblies can be eliminated; rapid fluid migration can be provided
that keeps cells at even temperatures; cooling tube sections
between rows of cells can be eliminated, thereby allowing more
cells to be packed into a given space; and even if a rupture occurs
in one of the heat pipe lumens, significant cooling/heating can
nevertheless be provided by way of other undamaged lumens within
the heat pipe.
[0019] FIG. 1 shows an example of an assembly 100 that is part of
an energy storage system. Particularly, the energy storage system
contains an interconnected array of energy storage elements, two
cells 102 of which are shown here. In this example, the cells are
physically secured and held in place (e.g., to a particular torque
value) by a pair of opposing clamshells: a top clamshell 104 and a
bottom clamshell 106. For example, the clamshells have openings
exposing the respective ends of each cell. In other
implementations, the cells can be secured by a different technique,
such as by a structure interleaved between cells.
[0020] Here, a flexible printed circuit 108 overlies and connects
electrical terminals of the cells 102. In this implementation, the
flexible printed circuit includes three layers: a flexible
conductive layer 110 sandwiched between a flexible bottom
insulating layer 112 and a flexible top insulating layer 114. The
conducting layer can be a uniform layer of metal, such as copper,
and the insulating layers can be uniform layers of polyimide (e.g.,
a Kapton.RTM. material). In other implementations, one or more
other materials can be used in lieu of or in combination with the
mentioned materials.
[0021] Here, the cells 102 are a type of rechargeable battery cell
having a flat top with terminals at one end. Particularly, each
cell has a center positive terminal 116 and a surrounding annular
negative terminal 118. For example, the annular negative terminal
can be part of, or mounted on, a main housing of the cell (e.g.,
the cell can) that extends along the length of the cell and forms
the other end of the cell (i.e., the bottom end in this
example).
[0022] The patterning of flexible printed circuit 108 produces die
cut areas 120 in the bottom insulating layer 112 to allow exposed
portions of conductive layer 110 to make electrical contact, for
example to selectively connect to the terminals of the cell(s).
Here, die cut areas 122 in top insulating layer 114 allow exposed
portions of conductive layer 110 to receive a device that produces
an electromechanical connection between the portion of conductive
layer interacting with the device and the underlying surface to be
joined (e.g., a terminal of one of the cells 102). Any of several
different types of devices and techniques can be used in making the
electromechanical joints. For example, spot welds 124 here join
portions of the conductive layer 110 to respective terminals of the
individual cells.
[0023] The energy storage system can be implemented as a source of
propulsion energy in an electric vehicle, to name just one example.
That is, a number of cells can be interconnected in the energy
storage system to form an array (e.g., a battery pack) that powers
the vehicle. In other implementations, the illustrated assembly can
also or instead power another aspect of a vehicle, or can be used
in a non-vehicle context, such as in a stationary storage.
[0024] In the illustrated embodiment, the cells 102 are oriented
vertically, and are shown standing on a heat pipe 126. The heat
pipe can be connected to a thermal management system (not shown) to
provide for thermal management of the energy storage system.
Cooling of the cells 102 can be performed using an evaporation end
126A that faces the cells, and at least one condensation end 126B.
The evaporation end can extend for at least the entire length
required by the array of cells, or part thereof. Here, the heat
pipe 126 has an L-shape when viewed from the side, with the
condensation end elevated above the evaporation end. In other
implementations, the heat pipe can have a different shape. For
example, and without limitation, more than one condensation end can
be provided. In some implementations, the heat pipe can instead
provide heating of the cells and the rest of the energy storage
system.
[0025] In this example, the assembly 100 has an electric insulator
layer 128 between the evaporation end 126A of the heat pipe 126 and
the bottom of the cells 102. This layer prevents electric contact
between the heat pipe (which can be a metal component) and the cell
housing. For example, a thermal interface material (TIM) can be
used to electrically insulate an anode terminal at the bottom of
the cell while allowing cooling/heating of the cells through the
same surface. In some implementations, the assembly is manufactured
by applying the electric insulator layer on the heat pipe, applying
adhesive onto the top of the layer (e.g., at each cell position),
and then positioning the cell or cells on the layer.
[0026] The heat pipe can be manufactured from any suitable
material. In some implementations, the heat pipe can be extruded
from metal and have at least one interior channel for the
phase-change fluid. The interior channel(s) can have one or more
features that aid the flow of fluid in the liquid phase and/or gas
phase. For example, a groove, powder and/or sponge can be provided
inside the heat pipe.
[0027] FIG. 2 shows an example of an energy storage system 200 with
heat pipes 202 that have an L-shape. In this example, an
evaporation surface 202A is oriented essentially horizontally
(e.g., inside a battery pack of an electric vehicle) and a
condensation surface 202B is oriented essentially vertically. A
module 204 of cells (e.g., lithium-ion cells of the 18650 type) is
here shown positioned on one of the heat pipes. The interface
between the module and the heat pipe is by conductive thermal
contact requiring a TIM. For example, the heat pipe can comprise
multiple adjacent parallel heat sections attached to each other
(e.g., by welding). The module can have more or fewer cells than
illustrated in this example, and/or the cells can be arranged in a
different configuration. For clarity, only one module of cells is
shown here. Implementations of energy storage systems can have any
number of modules.
[0028] The energy storage system 200 has at least one heat transfer
channel 206 that is in thermal exchange with the heat pipes 202. In
some implementations, an auxiliary system can circulate fluid, such
as coolant, in one or more channels inside the heat transfer
channel. For example, the energy storage system described here can
be incorporated as a battery pack in an electric (or hybrid)
vehicle, and a cooling system external to the battery pack can then
cool the fluid from the heat transfer channel, thereby removing
heat from the cells.
[0029] Here, the heat transfer channel 206 is provided in the
middle of the energy storage system 200, and the module 204 and
other modules can then be positioned in rows on each side of the
channel, for example in a location 208. The condensation
ends/surfaces of the respective heat pipes are here positioned so
that they about the sides of the heat transfer channel.
Accordingly, the heat pipes extend from the channel in opposite
directions. Here, the heat pipe 202 on which the module 204 is
positioned is shown to consist of six parallel heat pipe sections.
Solely as an example, each of such sections can contain 14 separate
internal channels, each of which individually operates according to
the principle of a heat pipe.
[0030] FIG. 3 shows another example of an energy storage system 300
with heat pipes 302 that have an L-shape. Each of the heat pipes
has a module 304 of cells associated with it. The cells are aligned
with each other so that one of their ends (e.g., the bottom end, or
a negative end) faces an evaporation surface 302A of the heat pipe.
In this implementation, the cells are positioned essentially
horizontally and the evaporation surface is vertical. A
condensation surface 302B of the heat pipe, however, is elevated
above the evaporation surface and is horizontal in this example. In
some implementations, a cooling surface can be formed by all the
condensation surfaces collectively, or can be a separate surface
applied on top of them. Such a cooling surface can then be used for
removing heat from all of the cell modules. For example, the
cooling surface can be provided with a common active cooling
channel (analogous to the heat transfer channel 206 of FIG. 2);
heat spreaders transverse to the cooling channel can then
accumulate heat from the respective condensation surfaces and
transport that heat to the cooling channel.
[0031] FIG. 4 shows an example of an energy storage system 400 with
heat pipes 402 that have a U-shape. That is, each of the heat pipes
has an evaporation surface 402A and two condensation surfaces 402B,
one at either end of the evaporation surface. Each of the heat
pipes has a module 404 of cells associated with it. For example,
this system can be useful in a vehicle, because the U-shaped heat
pipes provide increased independence from angularity changes (e.g.,
when the vehicle is operating on an inclined and/or graded
surface).
[0032] The energy storage system has a central heat transfer
channel 406 and one or more side heat transfer channels 408, each
of which is in thermal exchange with the heat pipes 402. Here, the
side heat transfer channels are provided at the ends of the heat
pipes opposite the central heat transfer channel. In this
implementation, the heat pipes are oriented along the length of the
modules 404. For example, this energy storage system can provide an
advantageously small ratio of condensation area relative to
evaporation area, which allows the cooling tube to occupy a
relatively small volume of the battery pack.
[0033] FIG. 5 shows another example of an energy storage system 500
with heat pipes 502 that have a U-shape. Each of the heat pipes has
an evaporation surface 502A and two condensation surfaces 502B, one
at either end of the evaporation surface. Each of the heat pipes
has a module 504 of cells associated with it. The energy storage
system has a central heat transfer channel 506 and one or more
cross member heat transfer channels 508, each of which is in
thermal exchange with the heat pipes 502. The cross member heat
transfer channels are transverse to the central channel; for
example, the cross member can extend equally far on both sides
thereof. A heat transfer medium (e.g., coolant) can flow in the
heat transfer channels to provide thermal exchange with the heat
pipes. Here, the heat pipes are oriented across the width of each
battery module. For example, this energy storage system can provide
an advantageously small ratio of condensation area relative to
evaporation area.
[0034] FIG. 6 shows another example of an energy storage system 600
with one or more heat pipes 602 that have a U-shape, also including
coolant tubes 604. Each of the heat pipes has an evaporation
surface 602A and two condensation surfaces 602B, one at either end
of the evaporation surface. This example shows a module 606 of
cells in the energy storage system. For example, during operation
the heat pipe can convey heat in both directions along the
evaporation surface, towards each respective condensation surface.
That is, the thermal flow inside the heat pipe is here parallel to
the plane of this drawing.
[0035] This energy storage system also has the coolant tubes 604
that are in thermal exchange with the heat pipes 602. In this
example, each of the coolant tubes has an essentially L-shaped
profile. For example, the profile of the L-shape can at least
partially correspond to the outer surface of the U-shaped heat
pipe. This provides an advantageously large surface area of contact
between the coolant tube and the heat pipe, which facilitates
thermal exchange between them. The coolant tubes 604 can provide
reversibility (i.e., the ability to do both heating and cooling) of
the heat pipe. For example, the L-shaped profile of the coolant
tubes facilitates removal of heat from the evaporation surface 602A
during cooling of the module, and also delivery of heat from the
condensation surfaces 602B to the module during heating. As another
example, the shape and configuration of the system in this example
can help reduce gravitational issues that might otherwise occur,
such as if the grooves of the heat pipe are not manufactured to
give effective capillary force. This configuration can also improve
the way that the U-shaped heat pipe is packaged inside a housing or
other structure that holds the energy storage system.
[0036] The coolant tube has one or more interior channels in which
coolant can be circulated within the system (i.e., the coolant can
flow in directions into, and out of, the plane of the figure). The
two coolant tubes in this example can have coolant flowing in the
opposite, or the same, direction as each other. In some
implementations, the coolant tube can be used for providing
reversible thermal transfer, such that the energy storage system
can be cooled or heated depending on what is needed. For example,
the condenser contact here extends onto the flat portion of the
heat pipe and can therefore also be used for delivering heat (e.g.,
from an external heating system) into the heat pipe, from where the
heat then flows into the individual cells.
[0037] FIG. 7 shows an example of an energy storage system 700 with
linear heat pipes 702. Each of the heat pipes has a module 704 of
cells associated with it. The energy storage system has a central
heat transfer channel 706 that can have coolant flowing through it.
Here, an end portion 702A of each heat pipe serves as an
evaporation area, and a central portion 702B of the heat pipe
(i.e., near the heat transfer channel) serves as a condensation
area. The internal channel(s) of the heat pipe can be truncated at
the central heat transfer channel, or can extend along the length
of the heat pipe. This energy storage system can provide a
relatively large ratio of evaporation area relative to condensation
area, and can work reversibly (i.e., to provide heating instead of
cooling). Also, this implementation can be efficient in terms of
volumetric energy density.
[0038] FIG. 8 shows another example of an energy storage system 800
with the linear heat pipes 702 from FIG. 7. The system here also
has the module 704 of cells, and the central heat transfer channel
706. In addition, the system has one or more side heat transfer
channels 802 through which coolant can flow. For example, the side
channel(s) can be positioned at the ends of the heat pipes. This
system can be useful in a vehicle, because the positions of the
central and side heat transfer channels provide increased
independence from angularity changes (e.g., when operating the
vehicle on an inclined and/or graded surface). As another example,
the system can provide reversible heat transfer, such as for
heating the cells instead of cooling them.
[0039] FIG. 9 shows an example of an energy storage system 900
where heat pipes 902 have a deformation 904 corresponding to a
cross section profile of a heat transfer channel 906. That is,
while the heat pipes are here generally linear in areas where the
battery cell modules are located, the heat pipe here has the
deformation so as to conform a condensation end of the heat pipe to
the shape of the heat transfer channel. The internal channel(s) of
the heat pipe can be truncated at the central heat transfer
channel, or can extend along the length of the heat pipe. For
example, this system can provide a smaller ratio of condensation
area relative to evaporation area than a corresponding L-shape heat
pipe.
[0040] FIG. 10 shows another example of an energy storage system
1000 with heat pipes 1002 having a U-shape, with thermal tubes on
top and bottom. Each heat pipe encloses a module 1004 of cells,
only one of which modules is shown here for simplicity. The heat
pipes are organized so that the system has four heat pipes across
its width, and three (sets of four) heat pipes along its length.
Other configurations and/or numbers of heat pipes can be used in
other implementations. For example, and without limitation, the
energy storage system could have a width of one heat pipe. In yet
another implementation, one or more heat pipes can instead be
transverse to the length of the energy storage system.
[0041] Here, the energy storage system 1000 is arranged so that the
larger surface of the heat pipes--i.e., the one abutting the
non-terminal ends of the cells--is generally vertical. The two
opposing heat pipe surfaces--which abut the side surfaces of the
outermost rows of cells--are generally horizontal.
[0042] Thermal tubes 1006 and 1008 are placed on the top and bottom
of the heat pipes, respectively. Each thermal tube is manufactured
of a material with sufficient thermal conductivity to absorb heat
from, or deliver heat into, the heat pipes through the facing
surface. For example, the thermal tube can have a number of
internal channels configured for having a fluid (e.g., coolant)
flowing therein. As such, the thermal tubes can be connected to an
external cooling/heating system (not shown), which can be located
outside the housing of the energy storage system.
[0043] As a first example, both the thermal tubes 1006 and 1008 can
be used for cooling the cells of the energy storage system by way
of a flowing coolant. In some implementations, coolant flows in
opposite directions in the two respective thermal tubes.
[0044] As a second example, the thermal tube 1006 (i.e., on top)
can be used for cooling the cells, and the thermal tube 1008 (i.e.,
on the bottom) can be used for heating the cells. This
configuration is advantageous in that the heat pipe operates aided
by gravity, rather than against gravity, and is more efficient as a
result. In a normally vertical heat pipe section the vapor will
always move upward unless the vehicle orientation is rotated by at
least 90 degrees. The above advantage can therefore be relatively
unaffected by vehicle orientation. Both when the batteries are
being cooled and when they are being heated, the less dense vapor
will move upward (opposite to gravity) and the fluid will move
downward (with gravity). That is, during operation, when the cells
(and/or other electrical devices in the system) are generating
heat, the upper thermal tube can serve to cool the system by way of
removing thermal energy from the heat pipes. In contrast, when the
cells (and/or the rest of the energy storage system) need to be
warmed up, such as before operating the system in a cold
environment, the lower thermal tube can serve to warm the system by
way of introducing thermal energy into the heat pipes. For example,
the flow of cooling/heating fluid can be directed to either the
upper or lower thermal tube, as applicable, by way of a valve, such
as a solenoid valve.
[0045] FIG. 11 shows another example of an energy storage system
1100 with heat pipes 1102 having a U-shape, with thermal tubes 1104
extending between manifolds 1106 and 1108 positioned at shorter
sides of the system. The heat pipes hold modules of cells adjacent
the thermal tubes, of which only modules 1110 and 1112 of cells are
shown for clarity. That is, in this example the thermal tubes are
parallel to the length of the energy storage system (e.g., a
battery pack).
[0046] The manifolds 1106-08 and the thermal tubes 1104 have one or
more channels inside them to facilitate flow of a fluid (e.g.,
coolant) to various parts of the system. For example, the manifold
1108 can be the inlet manifold, receiving fluid from at least one
inlet 1114, and the manifold 1106 can be the outlet manifold, with
fluid exiting through at least one outlet 1116. Between the two
manifolds, the fluid passes in the interior channels of the thermal
tubes 1104, and in so doing provides thermal exchange (e.g.,
cooling) of the cells by way of the heat pipes.
[0047] FIG. 11A is a cross section of the energy storage system in
FIG. 11. Particularly, modules 1110 and 1112 of cells are shown
positioned in heat pipes 1102A and 1102B, respectively. The heat
pipes, in turn, are positioned between respective thermal tubes
1104A, B and C. For example, in operation the heat from the module
1110 is conveyed by way of the heat pipe 1102A into the thermal
tubes 1104A and B, whereas the heat from the module 1112 is
conveyed by way of the heat pipe 1102B into the thermal tubes 1104B
and C. Some configurations can have the heat pipes and/or thermal
tubes arranged in other ways.
[0048] FIG. 12 shows another example of an energy storage system
1200 with heat pipes 1202 having a U-shape, with thermal tubes 1204
extending between manifolds 1206 and 1208 positioned at longer
sides of the system. The heat pipes hold modules of cells adjacent
the thermal tubes, of which only modules 1210 and 1212 of cells are
shown for clarity. That is, in this example the thermal tubes are
transverse to the length of the energy storage system (e.g., a
battery pack).
[0049] The manifolds 1206-08 and the thermal tubes 1204 have one or
more channels inside them to facilitate flow of a fluid (e.g.,
coolant) to various parts of the system. For example, the manifold
1208 can be the inlet manifold, receiving fluid from at least one
inlet 1214, and the manifold 1206 can be the outlet manifold, with
fluid exiting through at least one outlet 1216. Between the two
manifolds, the fluid passes in the interior channels of the thermal
tubes 1204, and in so doing provides thermal exchange (e.g.,
cooling) of the cells by way of the heat pipes.
[0050] FIG. 12A is a cross section of the energy storage system in
FIG. 12. Particularly, modules 1210 and 1212 of cells are shown
positioned in heat pipes 1202A and 1202B, respectively. The heat
pipes, in turn, are positioned between respective thermal tubes
1204A, B and C. For example, in operation the heat from the module
1210 is conveyed by way of the heat pipe 1202A into the thermal
tubes 1204A and B, whereas the heat from the module 1212 is
conveyed by way of the heat pipe 1202B into the thermal tubes 1204B
and C. Some configurations can have the heat pipes and/or thermal
tubes arranged in other ways.
[0051] As used herein, the term "heat pipe" is used in a broad
sense to include a number of techniques, such as phase change
thermal systems that use highly conductive materials and have a
substantially flat form factor. The term heat pipe includes, but is
not limited to, grooved style heat pipes, heat pins, vapor
chambers, pyrolytic graphite sheets, and other technologies where
heat is transferred between interfaces by way of thermal conduction
and phase transition.
[0052] A number of implementations have been described as examples.
Nevertheless, other implementations are covered by the following
claims.
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