TECHNICAL FIELD
The present application claims priority to Korean Patent Application No. 10-2020-
0082379 filed on July 3, 2020 in the Republic of Korea.
The present disclosure relates to a battery pack having a heat diffusion prevention
10 structure between adjacent battery modules, and an ESS and a vehicle including the battery
pack, and more particularly, to a battery pack having a structure capable of minimizing heat
transfer to adjacent battery modules when at least one battery module is heated among a
plurality of battery modules of the battery pack, and an ESS and a vehicle including the
battery pack.
15
BACKGROUND ART
A conventional battery pack as shown in FIG. 1 includes a battery module stack
having at least a pair of adjacent battery modules 1 and a heatsink 2 provided at one side of
the battery module stack. In the battery pack, the temperature of each battery module 1
20 may be maintained within a normal range by cooling in such a way that heat generated in
the battery module 1 is discharged to the outside through the heatsink 2 in a normal use
situation.
However, if one or more battery modules are abnormally heated among the plurality
3
of battery modules 1 of the battery module stack, heat exceeding an amount that can be
discharged through the heatsink 2 may be generated. In this case, the heat that is not
discharged through the heatsink 2 may be diffused to adjacent battery modules 1, which may
lead to ignition and/or explosion of the entire battery modules 1.
5 Referring to FIG. 2, a thermal insulation pad 3 may be applied to prevent heat from
being diffused from the battery module 1 that is abnormally heated to adjacent battery
modules 1 as described above. However, even in this case, if the heat dissipation through
the heatsink 2 reaches the limit, heat diffusion between the adjacent battery modules 1 is
unavoidable despite the thermal insulation pad 3.
10 As shown in FIG. 3, the amount of heat energy transferred from a battery module 1
having an abnormally high temperature (T1) due to abnormal heat generation to a battery
module 1 having a temperature (T2) within a normal range is proportional to a temperature
difference (T2 - T1) between the two battery modules 1 and is inversely proportional to the
width of the thermal insulation pad 3. Therefore, in a situation where the temperature
15 difference (T2 - T1) is very large due to abnormal heat generation, even if the thermal
insulation pad 3 with a low thermal conductivity coefficient is used, it is difficult to prevent
heat diffusion between the battery modules 1 unless the thermal insulation pad 3 has a very
large width.
In order to maximize the heat diffusion prevention effect, it is important to increase
20 the width of the thermal insulation pad 3. However the increase in the width of the thermal
insulation pad 3 causes a loss of energy density of the battery pack, so the increase in the
width of the thermal insulation pad 3 is inevitably limited.
Therefore, structural improvement is required to prevent heat from being diffused
4
to the entire battery modules due to abnormal heat generated in some battery modules of the
battery pack.
DISCLOSURE
5 Technical Problem
The present disclosure is designed to solve the problems of the related art, and
therefore the present disclosure is directed to preventing or minimizing heat diffusion to
entire battery modules due to abnormal heat generated in some battery modules of a battery
pack.
10 However, the technical problem to be solved by the present disclosure is not limited
to the above, and other objects not mentioned herein will be understood from the following
description by those skilled in the art.
Technical Solution
15 In one aspect of the present disclosure, there is provided a battery pack, comprising:
a battery module stack configured to include a first battery module and a second battery
module disposed adjacent to each other; a battery pack case configured to accommodate the
battery module stack; a heatsink interposed between a lower portion of the battery module
stack and the battery pack case or provided to contact a bottom of the battery pack case; a
20 heat spreader sheet interposed between the first battery module and the second battery
module; and an thermal insulation pad interposed between the first battery module and the
second battery module.
The heat spreader sheet may include a first heat spreader sheet adjacent to the first
5
battery module; and a second heat spreader sheet adjacent to the second battery module.
The thermal insulation pad may include a first thermal insulation pad interposed
between the first heat spreader sheet and the second heat spreader sheet; and a second
thermal insulation pad interposed between the first heat spreader sheet and the first battery
5 module and between the second heat spreader sheet and the second battery module,
respectively.
One side end of the first heat spreader sheet in a longitudinal direction may be bent
to face an upper surface of the first battery module, and one side end of the second heat
spreader sheet in a longitudinal direction may be bent to face an upper surface of the second
10 battery module.
The bent side end of the first heat spreader sheet and the bent side end of the second
heat spreader sheet may be in contact with the battery pack case, respectively.
The thermal insulation pad may further include a third thermal insulation pad
interposed between the bent side end of the first heat spreader sheet and the upper surface of
15 the first battery module and between the bent side end of the second heat spreader sheet and
the upper surface of the second battery module, respectively.
The other side end of the first heat spreader sheet and the other side end of the second
heat spreader sheet may not be in contact with the heatsink and the battery pack case,
respectively.
20
In another aspect of the present disclosure, there is provided a battery pack, a battery
module stack configured to include a first battery module and a second battery module
disposed adjacent to each other; a battery pack case configured to accommodate the battery
6
module stack; a heat spreader sheet interposed between the first battery module and the
second battery module; and an thermal insulation pad interposed between the first battery
module and the second battery module.
At least one of one side end and the other side end of the first heat spreader sheet in
5 a longitudinal direction may be bent to face an upper surface of the first battery module, and
at least one of one side end and the other side end of the second heat spreader sheet in a
longitudinal direction may be bent to face an upper surface of the second battery module.
The thermal insulation pad may further include a third thermal insulation pad
interposed between the bent side end of the first heat spreader sheet and the upper surface of
10 the first battery module and between the bent side end of the second heat spreader sheet and
the upper surface of the second battery module, respectively.
In another aspect of the present disclosure, there is provided an ESS, comprising the
battery pack according to the present disclosure.
15 In another aspect of the present disclosure, there is provided a vehicle, comprising
the battery pack according to the present disclosure.
Advantageous Effects
According to an embodiment of the present disclosure, it is possible to prevent or
20 minimize heat diffusion to entire battery modules due to abnormal heat generated in some
battery modules of a battery pack.
DESCRIPTION OF DRAWINGS
7
The accompanying drawings illustrate a preferred embodiment of the present
disclosure and together with the foregoing disclosure, serve to provide further understanding
of the technical features of the present disclosure, and thus, the present disclosure is not
construed as being limited to the drawing.
5 FIGS. 1 to 3 are diagrams showing a conventional battery pack.
FIGS. 4 to 6 diagrams showing a battery pack according to an embodiment of the
present disclosure.
FIGS. 7 and 8 are diagrams for illustrating a path along which heat generated from
a battery module is discharged.
10 FIGS. 9 and 10 diagrams showing a battery pack according to another embodiment
of the present disclosure.
BEST MODE
Hereinafter, preferred embodiments of the present disclosure will be described in
15 detail with reference to the accompanying drawings. Prior to the description, it should be
understood that the terms used in the specification and the appended claims should not be
construed as limited to general and dictionary meanings, but interpreted based on the
meanings and concepts corresponding to technical aspects of the present disclosure on the
basis of the principle that the inventor is allowed to define terms appropriately for the best
20 explanation. Therefore, the description proposed herein is just a preferable example for the
purpose of illustrations only, not intended to limit the scope of the disclosure, so it should
be understood that other equivalents and modifications could be made thereto without
departing from the scope of the disclosure.
8
A battery pack according to an embodiment of the present disclosure will be
described with reference to FIGS. 4 to 6.
First, referring to FIG. 4, the battery pack according to an embodiment of the present
5 disclosure includes a plurality of battery modules 10, a heatsink 20, a battery pack case 30,
a heat spreader sheet 40 and an thermal insulation pad 50.
The plurality of battery modules 10 are stacked in a state of facing each other to
form one battery module stack. The plurality of battery modules 10 includes a first battery
module 10a and a second battery module 10b disposed adjacent to each other. Each of the
10 battery modules 10 includes a plurality of battery cells (not shown) and a module case for
accommodating the plurality of battery cells.
The heatsink 20 is interposed between a lower portion of the battery module stack
and the battery pack case 30 or provided to contact a bottom of the battery pack case 30.
That is, the heatsink 20 may be located in the battery pack case 30 to directly contact the
15 battery modules 10, or alternatively, the heatsink 20 may be located out of the battery pack
case 30 to indirectly contact the battery modules 10 via the battery pack case 30. As
described above, the heatsink 20 is in direct or indirect contact with lower surfaces of the
plurality of battery modules 10 including the first battery module 10a and the second battery
module 10b to discharge heat generated from the battery modules 10 to the outside. The
20 heatsink 20 may be a water-cooling or air-cooling member.
If the heatsink 20 is located inside the battery pack case 30, in order to perform the
heat discharge function, a portion of the heatsink 20 may penetrate the battery pack case 30
and be exposed to the outside of the battery pack. In addition, if the heatsink 20 is in a
9
water-cooling type, a coolant inlet and a coolant outlet connected to the heatsink 20 to supply
a coolant to the inside of the heatsink 20 and discharge the coolant to the outside of the
heatsink 20 may be drawn out of the battery pack through the battery pack case 30. That
is, the heatsink 20 may be located inside the battery pack case 30, and the coolant inlet and
5 coolant outlet may be drawn out of the battery pack case 30.
The battery pack case 30 accommodates the battery module stack. The battery
pack case 30 may further accommodate the heatsink 20 in addition to the battery module
stack. The battery pack case 30 may be made of a metal material having excellent thermal
conductivity to ensure rigidity of the battery pack and to easily discharge heat generated
10 from the battery module stack to the outside.
The heat spreader sheet 40 and the thermal insulation pad 50 form one heat diffusion
prevention member. The heat diffusion prevention member is interposed between battery
modules 10 adjacent to each other, respectively. The heat diffusion prevention member
effectively prevents heat energy from being transferred between the battery modules 10
15 when heat exceeding the cooling performance of the heatsink 20 is generated due to
abnormal heat generation of at least one of the plurality of battery modules 10. The heat
diffusion prevention member primarily delays the heat diffusion between adjacent battery
modules 10 using the thermal insulation pad 50, and the heat diffusion prevention member
secondarily disperses the heat transferred along a thickness direction of the thermal
20 insulation pad 50 despite the application of the thermal insulation pad 50 toward an upper
portion of the battery pack, thereby minimizing heat diffusion to prevent rapid transition of
thermal runaway.
The heat spreader sheet 40 is made of, for example, a graphite sheet, and has a very
10
high heat transfer rate in an in-plane direction, namely in a direction parallel to the wide
surface of the sheet, rather than a thickness direction of the sheet.
Referring to FIG. 5 , the heat spreader sheet 40 includes a first heat spreader sheet
40a located adjacent to the first battery module 10a and a second heat spreader sheet 40b
5 located adjacent to the second battery module 10b. The first heat spreader sheet 40a is
shaped such that one side end thereof in a longitudinal direction extends to the upper portion
of the battery module stack. In addition, the first heat spreader sheet 40a is shaped such
that one side end thereof in the longitudinal direction is bent to face an upper surface of the
first battery module 10a.
10 Similarly, the second heat spreader sheet 40b is shaped such that one side end
thereof in the longitudinal direction extends to the upper portion of the battery module stack.
In addition, the second heat spreader sheet 40b is shaped such that one side end thereof in
the longitudinal direction is bent to face an upper surface of the second battery module 10b.
The bent side end of the first heat spreader sheet 40a and the bent side end of the second heat
15 spreader sheet 40b are spaced apart from the upper surfaces of the first battery module 10a
and the second battery module 10b, respectively. This is to prevent heat energy dispersed
upward through the first heat spreader sheet 40a and the second heat spreader sheet 40b from
being transferred toward the battery module 10 again.
The bent side end of the first heat spreader sheet 40a and the bent side end of the
20 second heat spreader sheet 40b may be in direct contact with the battery pack case 30,
respectively. In addition, unlike this, a TIM (thermal interface material) (not shown) may
be interposed between the bent side end of the first heat spreader sheet 40a and the battery
pack case 30 and between the bent side end of the second heat spreader sheet 40b and the
11
battery pack case 30, respectively.
The thermal insulation pad 50 includes a first thermal insulation pad 50a and a
second thermal insulation pad 50b. The first thermal insulation pad 50a is interposed
between the first heat spreader sheet 40a and the second heat spreader sheet 40b. The
5 second thermal insulation pad 50b is interposed between the first heat spreader sheet 40a
and the first battery module 10a and between the second heat spreader sheet 40b and the
second battery module 10b, respectively.
Meanwhile, the thermal insulation pad 50 may further include a third thermal
insulation pad 50c in addition to the first thermal insulation pad 50a and the second thermal
10 insulation pad 50b. The third thermal insulation pad 50c is interposed between the bent
side end of the first heat spreader sheet 40a and the upper surface of the first battery module
10a and between the bent side end of the second heat spreader sheet 40b and the upper
surface of the second battery module 10b, respectively. The third thermal insulation pad
50c prevents the heat energy dispersed upward through the first heat spreader sheet 40a and
15 the second heat spreader sheet 40b from being transferred toward the battery module 10
again.
Meanwhile, referring to FIG. 6, the other side end of the first heat spreader sheet
40a in the longitudinal direction and the other side end of the second heat spreader sheet 40b
in the longitudinal direction are not in contact with the heatsink 20 and the battery pack case
20 30, respectively, unlike FIG. 5. This is because, in a situation where the heatsink 20 cannot
perform normal cooling due to abnormal heat generation of some battery modules 10,
preventing additional heat energy from being transferred to the heatsink 20 through the heat
spreader sheet 40 may further increase the efficiency of heat energy dispersion.
12
Referring to FIGS. 7 and 8, in the battery pack according to an embodiment of the
present disclosure, a movement direction of heat energy when normal cooling is performed
and a dispersion direction of heat energy when some battery modules 10 are abnormally
heated are shown.
5 Referring to FIG. 7, in the case of normal cooling, the heat energy generated in the
battery modules 10a, 10b is discharged along the arrow direction through the heatsink 20
interposed between the lower portion of the battery module stack and the battery pack case
30 or provided to contact the bottom of the battery pack case 30, and thus heat transfer is not
generated between the battery modules 10a, 10b.
10 However, if cooling through the heatsink 20 is no longer performed smoothly since,
for example, abnormal heat is generated in the first battery module 10a, heat transfer is
generated along the arrow direction shown in FIG. 8 from the first battery module 10a toward
the second battery module 10b. In this case, the second thermal insulation pad 50b
primarily lowers the diffusion rate of heat energy, and the heat energy transferred along the
15 thickness direction of the second thermal insulation pad 50b is secondarily dispersed upward
by the first heat spreader sheet 40a and discharged to the outside through the battery pack
case 30. In addition, the heat energy transferred along the thickness direction of the first
heat spreader sheet 40a is slowed down again by means of the first thermal insulation pad
50a, and the heat energy transferred through the thickness direction of the first thermal
20 insulation pad 50a is dispersed upward by the second heat spreader sheet 40b and discharged
to the outside through the battery pack case 30. In addition, the diffusion rate of the
remaining heat energy transferred toward the second battery module 10b along the thickness
direction of the second heat spreader sheet 40b is minimized by means of the first thermal
13
insulation pad 50a.
As described above, the battery pack according to an embodiment of the present
disclosure may prevent the thermal runaway phenomenon caused by abnormal heat
generation in some battery modules 10 from being rapidly transferred by minimizing the
5 heat energy transferred between adjacent battery modules 10a, 10b when heat energy
exceeding the cooling capacity of the heatsink 20 is generated.
Next, a battery pack according to another embodiment of the present disclosure will
be described with reference to FIGS. 9 and 10.
10 The battery pack according to another embodiment of the present disclosure is
substantially identical to the battery pack according to an embodiment of the present
disclosure described above, except that the heatsink 20 functioning as a cooling member is
omitted and the specific structure of the heat diffusion prevention member is somewhat
different. Accordingly, in describing the battery pack according to another embodiment of
15 the present disclosure, the features identical to those of the former embodiment will not be
described in detail and only features different therefrom will be described in detail.
Since the heatsink 20 is omitted in the battery pack according to another
embodiment of the present disclosure, unlike in the former embodiment, cooling is
performed through the battery pack case 30.
20 The heatsink 20 is omitted because, in consideration of the capacity of the battery
pack, there is no need to additionally provide a cooling member for forced cooling since
much heat is not generated during normal use. However, if abnormal heat is generated in,
for example, the first battery module 10a, a sufficient cooling rate may not be ensured only
14
by discharging heat energy through the battery pack case 30, so heat transfer may be
generated between the battery modules 10a, 10b.
Referring to FIG. 9, in order to prevent or minimize such heat transfer, the battery
pack according to another embodiment of the present disclosure includes a heat diffusion
5 prevention member interposed between adjacent battery modules 10a, 10b, as in the former
embodiment. In this case, the lower surfaces of the plurality of battery modules 10a, 10b
are in contact with the battery pack case 30.
Referring to FIG. 10, in the battery pack according to another embodiment of the
present disclosure, unlike that shown in FIG. 9, both the first heat spreader sheet 40a and the
10 second heat spreader sheet 40b extend in both directions at the upper and lower portions of
the battery module stack. In addition, the first heat spreader sheet 40a is bent not only at
one side end thereof in the longitudinal direction but also at the other side end thereof to face
the lower surface of the first battery module 10a. Similarly, the second heat spreader sheet
40b is also bent not only at one side end thereof in the longitudinal direction but also at the
15 other side end thereof to face the lower surface of the second battery module 10b.
Accordingly, the third thermal insulation pad 50c may also be interposed between
the bent other side end of the first heat spreader sheet 40a and the lower surface of the first
battery module 10a and between the bent other side end of the second heat spreader sheet
40b and the lower surface of the second battery module 10b.
20
Meanwhile, the battery pack according to the present disclosure as described above
may be applied as a battery pack for a vehicle, and may also be applied as a battery pack for
an energy storage system (ESS). Therefore, the vehicle and the ESS according to an
15
embodiment of the present disclosure include at least one battery pack according to the
present disclosure, respectively.
The present disclosure has been described in detail. However, it should be
5 understood that the detailed description and specific examples, while indicating preferred
embodiments of the disclosure, are given by way of illustration only, since various changes
and modifications within the scope of the disclosure will become apparent to those skilled
in the art from this detailed description.
10 Reference Signs
10: battery module
10a: first battery module
10b: second battery module
20: heatsink
15 30: battery pack case
40: heat spreader sheet
40a: first heat spreader sheet
40b: second heat spreader sheet
50: thermal insulation pad
20 50a: first thermal insulation pad
50b: second thermal insulation pad
50c: third thermal insulation pad
16
WHAT IS CLAIMED IS:
1. A battery pack, comprising:
a battery module stack configured to include a first battery module and a second
5 battery module disposed adjacent to each other;
a battery pack case configured to accommodate the battery module stack;
a heatsink interposed between a lower portion of the battery module stack and the
battery pack case or provided to contact a bottom of the battery pack case;
a heat spreader sheet interposed between the first battery module and the second
10 battery module; and
an thermal insulation pad interposed between the first battery module and the second
battery module.
2. The battery pack according to claim 1,
15 wherein the heat spreader sheet includes:
a first heat spreader sheet adjacent to the first battery module; and
a second heat spreader sheet adjacent to the second battery module.
3. The battery pack according to claim 2,
20 wherein the thermal insulation pad includes:
a first thermal insulation pad interposed between the first heat spreader sheet and
the second heat spreader sheet; and
a second thermal insulation pad interposed between the first heat spreader sheet and
17
the first battery module and between the second heat spreader sheet and the second battery
module, respectively.
4. The battery pack according to claim 3,
5 wherein one side end of the first heat spreader sheet in a longitudinal direction is
bent to face an upper surface of the first battery module, and
one side end of the second heat spreader sheet in a longitudinal direction is bent to
face an upper surface of the second battery module.
10 5. The battery pack according to claim 4,
wherein the bent side end of the first heat spreader sheet and the bent side end of the
second heat spreader sheet are in contact with the battery pack case, respectively.
6. The battery pack according to claim 4,
15 wherein the thermal insulation pad further includes a third thermal insulation pad
interposed between the bent side end of the first heat spreader sheet and the upper surface of
the first battery module and between the bent side end of the second heat spreader sheet and
the upper surface of the second battery module, respectively.
20 7. The battery pack according to claim 4,
wherein the other side end of the first heat spreader sheet in the longitudinal
direction and the other side end of the second heat spreader sheet in the longitudinal direction
are not in contact with the heatsink and the battery pack case, respectively.
18
8. A battery pack, comprising:
a battery module stack configured to include a first battery module and a second
battery module disposed adjacent to each other;
5 a battery pack case configured to accommodate the battery module stack;
a heat spreader sheet interposed between the first battery module and the second
battery module; and
an thermal insulation pad interposed between the first battery module and the second
battery module.
10
9. The battery pack according to claim 8,
wherein the heat spreader sheet includes:
a first heat spreader sheet adjacent to the first battery module; and
a second heat spreader sheet adjacent to the second battery module.
15
10. The battery pack according to claim 9,
wherein the thermal insulation pad includes:
a first thermal insulation pad interposed between the first heat spreader sheet and
the second heat spreader sheet; and
20 a second thermal insulation pad interposed between the first heat spreader sheet and
the first battery module and between the second heat spreader sheet and the second battery
module, respectively.
19
11. The battery pack according to claim 10,
wherein at least one of one side end and the other side end of the first heat spreader
sheet in a longitudinal direction is bent to face an upper surface of the first battery module,
and
5 at least one of one side end and the other side end of the second heat spreader sheet
in a longitudinal direction is bent to face an upper surface of the second battery module.
12. The battery pack according to claim 11,
wherein the bent side end of the first heat spreader sheet and the bent side end of the
10 second heat spreader sheet are in contact with the battery pack case, respectively.
13. The battery pack according to claim 11,
wherein the thermal insulation pad further includes a third thermal insulation pad
interposed between the bent side end of the first heat spreader sheet and the upper surface of
15 the first battery module and between the bent side end of the second heat spreader sheet and
the upper surface of the second battery module, respectively.
14. An energy storage system, comprising the battery pack according to any one
of claims 1 to 13.
20
15. A vehicle, comprising the battery pack according to any one of claims 1 to
13.