A battery pack having a heat diffusion prevention structure between adjacent battery modules, an ESS including the same, and an automobile

Abstract

To prevent or minimize thermal diffusion to all battery modules due to abnormal heat generated by a part of the battery modules comprising a battery pack.SOLUTION: A battery pack includes: a battery module laminate containing a first battery module and a second battery module arranged adjacent to each other; a pack case accommodating the battery module laminate; a heat sink interposed between a lower part of the battery module laminate and the pack case or in contact with the lower part of the pack case; a heat spreader sheet between the first battery module and the second battery module; and a thermal insulating pad between the first battery module and the second battery module.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a battery pack having a heat diffusion prevention structure between adjacent battery modules, an ESS (Energy Storage System), and a vehicle including the same. More specifically, when abnormal heat generation occurs in at least one battery module among a plurality of battery modules constituting the battery pack, the present invention relates to a battery pack having a structure capable of minimizing heat transfer to adjacent battery modules, an ESS including the same, and a vehicle.

[0002] This application claims priority based on Korean Patent Application No. 10-2020-0082379 filed on July 3, 2020, and all of the contents disclosed in the specification and drawings of the corresponding application are incorporated herein.

Background Art

[0003] A conventional battery pack as shown in FIG. 1 includes a battery module laminate including at least a pair of adjacent battery modules 1, and a heat sink 2 provided on one side of the battery module laminate. In such a battery pack, in a normal use situation, heat generated in the battery module 1 is cooled by being discharged to the outside through the heat sink 2, so that the temperature of each battery module 1 is maintained within a normal range.

[0004] However, when abnormal heat generation occurs in one or more of the plurality of battery modules 1 forming the battery module laminate, heat exceeding the amount that can be discharged from the heat sink 2 may be generated. In this case, the heat that has not been discharged from the heat sink 2 may diffuse to adjacent battery modules 1, which may lead to ignition and / or explosion of the entire battery module 1.

[0005] 2, a heat insulating pad 3 is applied to prevent heat diffusion from the battery module 1 where abnormal heat generation has occurred to the adjacent battery module 1. However, even in this case, when the heat dissipation from the heat sink 2 reaches its limit, heat diffusion to the adjacent battery module 1 cannot be avoided despite the application of the heat insulating pad 3.

[0006] 3, the amount of thermal 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 the normal range is proportional to the temperature difference (T2 - T1) between the two battery modules 1 and inversely proportional to the width of the heat insulating pad 3. Therefore, in a situation where the temperature difference (T2 - T1) is very large due to abnormal heat generation, even if a heat insulating pad 3 with a low thermal conductivity is used, it is difficult to prevent heat diffusion between the battery modules 1 unless the width of the heat insulating pad 3 is very large.

[0007] In order to maximize the effect of preventing heat diffusion, it is important to increase the width of the heat insulating pad 3. However, since an increase in the width of the heat insulating pad 3 results in a loss of energy density of the battery pack, the amount of increase in the width of the heat insulating pad 3 is limited.

[0008] Therefore, structural improvements are required to prevent abnormal heat generated in some battery modules constituting the battery pack from spreading to all battery modules. Summary of the Invention [Problem to be solved by the invention]

[0009] The present invention has been made in consideration of the above problems, and aims to prevent or minimize heat diffusion to all battery modules due to abnormal heat generated in some battery modules constituting a battery pack.

[0010] However, the technical problems to be solved by the present invention are not limited to the foregoing problems, and other problems not mentioned will be clearly understood by those skilled in the art from the following description of the invention.

Means for Solving the Problems

[0011] A battery pack according to an embodiment of the present invention for achieving the above problems includes a battery module laminate including a first battery module and a second battery module arranged adjacent to each other, a pack case for housing the battery module laminate, a heat sink interposed between the lower part of the battery module laminate and the pack case or in contact with the lower part of the pack case, a heat spreader sheet interposed between the first battery module and the second battery module, and a heat insulating pad interposed between the first battery module and the second battery module.

[0012] The heat spreader sheet may include a first heat spreader sheet adjacent to the first battery module and a second heat spreader sheet adjacent to the second battery module.

[0013] The heat insulating pad may include a first heat insulating pad interposed between the first heat spreader sheet and the second heat spreader sheet, and second heat insulating pads 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.

[0014] The first heat spreader sheet has a form bent so that one end portion faces the upper surface of the first battery module, and the second heat spreader sheet may have a form bent so that one end portion faces the upper surface of the second battery module.

[0015] The bent end portions of the first heat spreader sheet and the second heat spreader sheet may each be in contact with the pack case.

[0016] The heat insulating pad may further include a third heat insulating pad interposed between the folded end of the first heat spreader sheet and the upper surface of the first battery module and between the folded end of the second heat spreader sheet and the upper surface of the second battery module, respectively.

[0017] The other end of the first heat spreader sheet and the other end of the second heat spreader sheet may not contact the heat sink and the pack case, respectively.

[0018] In addition, a battery pack according to another embodiment of the present invention for achieving the above object includes a battery module stack including a first battery module and a second battery module arranged adjacent to each other, a pack case accommodating the battery module stack, a heat spreader sheet interposed between the first battery module and the second battery module, and a heat insulating pad interposed between the first battery module and the second battery module.

[0019] The first heat spreader sheet may have a shape in which at least one of one and the other longitudinal ends is bent to face the top surface of the first battery module, and the second heat spreader sheet may have a shape in which at least one of one and the other longitudinal ends is bent to face the top surface of the second battery module.

[0020] The heat insulating pad may further include a third heat insulating pad interposed between the folded end of the first heat spreader sheet and the upper surface of the first battery module and between the folded end of the second heat spreader sheet and the upper surface of the second battery module, respectively.

[0021] In order to achieve the above object, an ESS according to another embodiment of the present invention includes the battery pack according to the present invention as described above.

[0022] In order to achieve the above object, a vehicle according to another embodiment of the present invention includes the battery pack according to the present invention as described above. [Effects of the Invention]

[0023] According to one aspect of the present invention, it is possible to prevent or minimize the spread of heat to all battery modules due to abnormal heat generated in some battery modules constituting a battery pack.

[0024] The following drawings attached to this specification illustrate preferred embodiments of the present invention and, together with the detailed description of the invention, serve to further understand the technical concept of the present invention, so the present invention should not be interpreted as being limited to the matters described in the drawings. [Brief description of the drawings]

[0025]

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Figure 10

Best Mode for Carrying Out the Invention

[0026] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, the terms and words used in this specification and the claims should not be construed as being limited to ordinary or dictionary meanings, and the inventor himself must interpret them in accordance with the meaning and concept corresponding to the technical idea of the present invention in accordance with the principle that he can appropriately define the concept of the terms in order to explain the invention in the best way. Therefore, it must be understood that the embodiments described in this specification and the configurations shown in the drawings are only one of the most preferred embodiments of the present invention and do not represent all of the technical ideas of the present invention. Therefore, there may be various equivalents and modifications that can replace them at the time of this application.

[0027] Referring to FIGS. 4 to 6, a battery pack according to an embodiment of the present invention will be described.

[0028] First, referring to FIG. 4, a battery pack according to an embodiment of the present invention includes a plurality of battery modules 10, a heat sink 20, a pack case 30, a heat spreader sheet 40, and a heat insulating pad 50.

[0029] The plurality of battery modules 10 are stacked in a state of facing each other to form a battery module stack. The plurality of battery modules 10 include a first battery module 10a and a second battery module 10b arranged adjacent to each other. Each battery module 10 includes a plurality of battery cells (not shown) and a module case for housing the plurality of battery cells.

[0030] The heat sink 20 is interposed between the lower part of the battery module stack and the pack case 30, or is in contact with the lower part of the pack case 30. That is, the heat sink 20 may be located inside the pack case 30 and in direct contact with the battery modules 10, or may be located outside the pack case 30 and indirectly in contact with the battery modules 10 via the pack case 30. In this manner, the heat sink 20 is in direct or indirect contact with the lower surfaces of the plurality of battery modules 10, including the first battery module 10a and the second battery module 10b, to dissipate heat generated in the battery modules 10 to the outside. The heat sink 20 may be a water-cooled or air-cooled cooling member.

[0031] When the heat sink 20 is located inside the pack case 30, a portion of the heat sink 20 may penetrate the pack case 30 and be exposed to the outside of the battery pack to perform a heat dissipation function. Also, when the heat sink 20 is a water-cooled type, a refrigerant inlet and a refrigerant outlet connected to the heat sink 20 to supply a refrigerant to the inside of the heat sink 20 may penetrate the pack case 30 and be drawn out to the outside of the battery pack. That is, the heat sink 20 may be located inside the pack case 30, and the refrigerant inlet and the refrigerant outlet may be drawn out to the outside of the pack case 30.

[0032] The pack case 30 accommodates the battery module stack and may further accommodate a heat sink 20 outside the battery module stack. The pack case 30 may be made of a metal material with excellent thermal conductivity to ensure the rigidity of the battery pack and to easily dissipate heat generated in the module stack to the outside.

[0033] The heat spreader sheet 40 and the heat insulating pad 50 form a single heat diffusion prevention member. Such a heat diffusion prevention member is interposed between adjacent battery modules 10. The heat diffusion prevention member effectively prevents thermal energy from being transferred to other battery modules 10 when abnormal heat generation in at least one of the battery modules 10 generates heat that exceeds the cooling capacity of the heat sink 20. The heat diffusion prevention member primarily delays heat diffusion to adjacent battery modules 10 using the heat insulating pad 50, and secondarily distributes heat transferred along the thickness direction of the heat insulating pad 50 toward the top of the battery pack despite the use of the heat insulating pad 50, thereby minimizing heat diffusion and preventing rapid transition to thermal runaway.

[0034] The heat spreader sheet 40 is, for example, a sheet made of graphite material, and has a characteristic that the heat transfer rate is much higher in the in-plane direction, i.e., in the direction parallel to the wide surface of the sheet, than in the thickness direction of the sheet.

[0035] 5, the heat spreader sheet 40 includes a first heat spreader sheet 40a positioned adjacent to the first battery module 10a and a second heat spreader sheet 40b positioned adjacent to the second battery module 10b. One longitudinal end of the first heat spreader sheet 40a extends toward the top of the battery module stack. In addition, one longitudinal end of the first heat spreader sheet 40a is bent to face the top surface of the first battery module 10a.

[0036] Similarly, the second heat spreader sheet 40b has a form in which one longitudinal end extends to the upper part of the battery module laminate. Also, the second heat spreader sheet 40b has a form in which one longitudinal end is bent so as to face the upper surface of the second battery module 10b. The bent ends of the first heat spreader sheet 40a and the bent ends of the second heat 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 the heat energy dispersed upward through the first heat spreader sheet 40a and the second heat spreader sheet 40b from being further transmitted to the battery module 10 side.

[0037] The bent ends of the first heat spreader sheet 40a and the bent ends of the second heat spreader sheet 40b may be in direct contact with the pack case 30, respectively. Also, different from this, a thermal interface material (TIM) (not shown) may be interposed between the bent end of the first heat spreader sheet 40a and the pack case 30 and between the bent end of the second heat spreader sheet 40b and the pack case 30 for adhesion and improvement of the heat transfer rate, respectively.

[0038] The heat insulating pad 50 includes a first heat insulating pad 50a and a second heat insulating pad 50b. The first heat insulating pad 50a is interposed between the first heat spreader sheet 40a and the second heat spreader sheet 40b. The second heat insulating 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.

[0039] On the other hand, the heat insulation pad 50 may further include a third heat insulation pad 50c in addition to the first heat insulation pad 50a and the second heat insulation pad 50b. The third heat insulation pad 50c is interposed between the bent end of the first heat spreader sheet 40a and the upper surface of the first battery module 10a and between the bent end of the second heat spreader sheet 40b and the upper surface of the second battery module 10b, respectively. The third heat insulation pad 50c prevents the heat energy dispersed upward through the first heat spreader sheet 40a and the second heat spreader sheet 40b from being further transmitted to the battery module 10 side.

[0040] On the other hand, referring to FIG. 6, unlike what is shown in FIG. 5, the other longitudinal end of the first heat spreader sheet 40a and the other longitudinal end of the second heat spreader sheet 40b do not contact the heat sink 20 and the pack case 30, respectively. This is because in a situation where the heat sink 20 does not cool normally due to abnormal heat generation of some of the battery modules 10, preventing further transmission of heat energy to the heat sink 20 through the heat spreader sheet 40 can further improve the efficiency of heat energy dispersion.

[0041] Referring to FIGS. 7 and 8, in the battery pack according to an embodiment of the present invention, the heat energy transfer direction when normal cooling is performed and the heat energy dispersion direction when abnormal heat generation occurs in some of the battery modules 10 are shown.

[0042] Referring to FIG. 7, when normal cooling is performed, the heat energy generated in the battery modules 10a and 10b is discharged along the arrow direction from the heat sink 20 that is interposed between the lower part of the battery module laminate and the pack case 30 or contacts the lower part of the pack case 30. As a result, heat transfer between the battery modules 10a and 10b does not occur.

[0043] However, for example, if abnormal heat generation occurs in the first battery module 10a and cooling by the heat sink 20 can no longer be carried out smoothly, heat transfer will occur from the first battery module 10a toward the second battery module 10b along the direction of the arrow as shown in FIG. 8. In this case, the second heat insulation pad 50b primarily reduces the diffusion rate of thermal energy, and the thermal energy transmitted along the thickness direction of the second heat insulation pad 50b is secondarily dispersed upward by the first heat spreader sheet 40a and discharged to the outside through the pack case 30. Also, the thermal energy transmitted along the thickness direction of the first heat spreader sheet 40a has its diffusion rate further delayed by the first heat insulation pad 50a, and the thermal energy transmitted in the thickness direction of the first heat insulation pad 50a is dispersed upward by the second heat spreader sheet 40b and discharged to the outside through the pack case 30. Further, the remaining thermal energy transmitted toward the second battery module 10b along the thickness direction of the second heat spreader sheet 40b has its diffusion rate minimized by the first heat insulation pad 50a.

[0044] Thus, when thermal energy exceeding the cooling capacity of the heat sink 20 is generated, the battery pack according to an embodiment of the present invention can prevent a rapid transition to a thermal runaway state due to abnormal heat generation occurring in some of the battery modules 10 by minimizing the thermal energy transmitted to the adjacent battery modules 10a and 10b.

[0045] Next, with reference to FIGS. 9 and 10, a battery pack according to another embodiment of the present invention will be described.

[0046] The battery pack according to this embodiment of the present invention differs from the battery pack according to the above-described embodiment of the present invention only in that the heat sink 20 functioning as a cooling member is omitted and in part in the specific structure of the heat diffusion prevention member, but the other components are substantially the same. Therefore, in describing the battery pack according to this embodiment of the present invention, descriptions that overlap with the above-described embodiment will be omitted and only the differences will be described.

[0047] Unlike the above-described embodiments, the battery pack according to another embodiment of the present invention has a configuration in which the heat sink 20 is omitted, and therefore cooling is performed using the pack case 30.

[0048] The reason for omitting the heat sink 20 is that, considering the capacity of the battery pack, not much heat is generated during normal use, so there is no need to provide an additional cooling member for forced cooling. However, if abnormal heat is generated in the first battery module 10a, for example, the dissipation of thermal energy by the pack case 30 alone may not be enough to ensure a sufficient cooling rate, and heat transfer may occur between the battery modules 10a and 10b.

[0049] 9, a battery pack according to another embodiment of the present invention includes a heat diffusion prevention member interposed between adjacent battery modules 10 a, 10 b in order to prevent or minimize the occurrence of such heat transfer, as in the above-described embodiment. In this case, the bottom surfaces of the plurality of battery modules 10 a, 10 b come into contact with the pack case 30.

[0050] Referring to FIG. 10, different from what is shown in FIG. 9, the battery pack according to another embodiment of the present invention has a form in which the first heat spreader sheet 40a and the second heat spreader sheet 40b extend in both the upper and lower directions of the battery module laminate. Further, the first heat spreader sheet 40a has a form in which not only one end portion in the longitudinal direction but also the other end portion is bent to face the lower surface of the first battery module 10a. Similarly, the second heat spreader sheet 40b also has a form in which not only one end portion in the longitudinal direction but also the other end portion is bent to face the lower surface of the second battery module 10b.

[0051] Accordingly, the third heat insulating pad 50c can also be interposed between the bent other end portion of the first heat spreader sheet 40a and the lower surface of the first battery module 10a and between the bent other end portion of the second heat spreader sheet 40b and the lower surface of the second battery module 10b.

[0052] On the other hand, the battery pack according to the present invention as described above is applicable to an automotive battery pack and is also applicable to a battery pack for an ESS (Energy Storage System). Therefore, an automobile and an ESS according to an embodiment of the present invention each include at least one battery pack according to the present invention.

[0053] As described above, the present invention has been described with reference to the limited embodiments and drawings, but the present invention is not limited thereto, and it goes without saying that various modifications and variations can be made by those having ordinary knowledge in the technical field to which the present invention pertains within the equivalent scope of the technical idea and the claims of the present invention.

[0054] Furthermore, it is also preferable that the following examples are included in the present invention. [1] A battery module laminate including a first battery module and a second battery module arranged adjacent to each other, A pack case for housing the battery module laminate, A heat sink interposed between the lower part of the battery module laminate and the pack case or in contact with the lower part of the pack case, a heat spreader sheet interposed between the first battery module and the second battery module, and a heat insulating pad interposed between the first battery module and the second battery module, the battery pack comprising the same. [2] 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. The battery pack according to [1]. [3] The heat insulating pad includes a first heat insulating pad interposed between the first heat spreader sheet and the second heat spreader sheet, and second heat insulating pads respectively interposed between the first heat spreader sheet and the first battery module and between the second heat spreader sheet and the second battery module. The battery pack according to [2]. [4] The first heat spreader sheet has a form bent such that one side end faces the upper surface of the first battery module, and the second heat spreader sheet has a form bent such that one side end faces the upper surface of the second battery module. The battery pack according to [3]. [5] The bent end of the first heat spreader sheet and the bent end of the second heat spreader sheet are each in contact with the pack case. The battery pack according to [4]. [6] The heat insulating pad A battery pack according to [4], further comprising third heat insulating pads respectively interposed between the bent end of the first heat spreader sheet and the upper surface of the first battery module and between the bent end of the second heat spreader sheet and the upper surface of the second battery module. [7] A battery pack according to [4], wherein the other end of the first heat spreader sheet and the other end of the second heat spreader sheet do not contact the heat sink and the pack case, respectively. [8] A battery pack comprising a battery module laminate including a first battery module and a second battery module arranged adjacent to each other, a pack case for housing the battery module laminate, a heat spreader sheet interposed between the first battery module and the second battery module, and a heat insulating pad interposed between the first battery module and the second battery module. [9] 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. A battery pack according to [8].

[10] The heat insulating pad includes a first heat insulating pad interposed between the first heat spreader sheet and the second heat spreader sheet, and second heat insulating pads respectively interposed between the first heat spreader sheet and the first battery module and between the second heat spreader sheet and the second battery module. A battery pack according to [9].

[11] The first heat spreader sheet has a form that is bent such that at least one of the one-side end portion and the other-side end portion in the longitudinal direction faces the upper surface of the first battery module. The battery pack according to

[10] , wherein the second heat spreader sheet has a form that is bent such that at least one of the one-side end portion and the other-side end portion in the longitudinal direction faces the upper surface of the second battery module.

[12] The battery pack according to

[11] , wherein the bent end portion of the first heat spreader sheet and the bent end portion of the second heat spreader sheet each contact the pack case.

[13] The heat insulation pad The battery pack according to

[11] , further including third heat insulation pads respectively interposed between the bent end portion of the first heat spreader sheet and the upper surface of the first battery module and between the bent end portion of the second heat spreader sheet and the upper surface of the second battery module.

[14] An ESS including the battery pack according to any one of [1] to

[13] .

[15] An automobile including the battery pack according to any one of [1] to

[13] .

Description of Signs

[0055] 10 Battery module 10a First battery module 10b Second battery module 20 Heat sink 30 Pack case 40 Heat spreader sheet 40a First heat spreader sheet 40b Second heat spreader sheet 50 Heat insulation pad 50a First heat insulation pad 50b Secondary Heat Insulation Pad 50c 3rd insulation pad

Claims

1. A battery module laminate including a first battery module and a second battery module arranged adjacent to each other, a pack case for housing the battery module laminate, a heat spreader sheet interposed between the first battery module and the second battery module, and a heat insulation pad interposed between the first battery module and the second battery module, wherein the heat spreader sheet is in direct contact with or in contact with the pack case via a heat conductive material so as to extend to the upper part of the battery module laminate and transfer heat to the pack case, a battery pack.

2. Further including a heat sink interposed between the lower part of the battery module laminate and the pack case or in contact with the lower part of the pack case, wherein one side end of the heat spreader sheet is in contact with at least one of the pack case and the heat sink, the battery pack according to claim 1.

3. The battery pack according to claim 2, wherein the other side end of the heat spreader sheet does not contact the heat sink and the pack case.

4. The battery pack according to claim 2, wherein one side end of the heat spreader sheet has a form bent so as to face the battery module laminate.

5. The battery pack according to claim 4, wherein the bent end of the heat spreader sheet is provided so as to be separated from the battery module laminate.

6. The heat insulation pad further includes a third heat insulation pad interposed between the bent one side end of the heat spreader sheet and the battery module laminate, the battery pack according to claim 5.

7. The heat insulation pad includes a first heat insulation pad interposed between the heat spreader sheet and the second battery module, and a second heat insulation pad interposed between the heat spreader sheet and the first battery module, the battery pack according to claim 1.

8. The heat spreader sheet includes a first heat spreader sheet located on the first battery module side, The battery pack according to claim 1, comprising: a second heat spreader sheet positioned on the second battery module side.

9. A first heat insulation pad interposed between the first heat spreader sheet and the second heat spreader sheet; The battery pack according to claim 8, comprising: second heat insulation pads respectively interposed between the first heat spreader sheet and the first battery module and between the second heat spreader sheet and the second battery module.

10. An ESS including the battery pack according to any one of claims 1 to 9.

11. An automobile including the battery pack according to any one of claims 1 to 9.

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