Battery pack

Abstract

A battery pack is provided with: a battery module comprising a plurality of stacked battery cells, the battery cells each having a relief valve that opens when internal pressure rises; a case accommodating the battery module; an exhaust path provided along the first direction at a position facing the relief valve of the housing in the second direction; and a sealing member provided between the case and the battery module and disposed around the exhaust passage so as to define the exhaust passage.

Description

Technical Field

[0001] The present disclosure relates to a battery pack. Background Art

[0002] Japanese Patent Application Laid-Open No. 2023-017448 discloses a battery pack having a plurality of stacked battery cells and an exhaust duct through which gas exhausted from the battery cells flows. Each battery cell has an exhaust valve. The internal space of the exhaust duct forms a smoke exhaust path. Summary of the invention

[0003] In Japanese Patent Application Laid-Open No. 2023-017448, the ejection released from the exhaust valve flows in the exhaust duct. Therefore, when the exhaust duct is small, when a large amount of ejection is released, the exhaust path may be clogged. In addition, since the exhaust duct needs to be provided on the resin frame, the number of components increases.

[0004] The present disclosure provides a battery pack capable of releasing ejected matter to the outside with a simple structure.

[0005] A technical solution disclosed herein involves a battery pack comprising: a battery module comprising a battery cell, wherein the battery cell has a safety valve that opens when the internal pressure rises, and the battery module is formed by stacking a plurality of the battery cells in a first direction; a shell that accommodates the battery module; an exhaust path that is arranged in the shell along the first direction and is opposite to the safety valve in a second direction; and a sealing member that is arranged between the shell and the battery module and is configured around the exhaust path in a manner to divide the exhaust path.

[0006] According to the present disclosure, it is possible to provide a battery pack capable of releasing ejected matter to the outside with a simple configuration. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will be described below with reference to the accompanying drawings, in which like reference numerals represent like elements.

[0008] Figure 1 It is a plan view schematically showing the structure of a battery pack.

[0009] Figure 2 It is an xz cross-sectional view schematically showing the structure of the battery pack.

[0010] Figure 3 It is a yz cross-sectional view schematically showing the structure of the battery pack.

[0011] Figure 4 It is an xz cross-sectional view schematically showing the structure of a battery pack according to a modification.

[0012] Figure 51 is an xz cross-sectional view schematically showing the structure of the battery pack of Structural Example 1.

[0013] Figure 6 It is an xz cross-sectional view schematically showing the structure of the battery pack of Structural Example 2. DETAILED DESCRIPTION

[0014] Hereinafter, with reference to the accompanying drawings, specific embodiments of the present disclosure are described in detail. However, the present disclosure is not limited to the following embodiments. In addition, in order to make the description clear, the following description and drawings are appropriately simplified.

[0015] First, refer to Figure 1 , the battery pack 100 is described. Figure 1 It is a top view schematically showing the structure of the battery pack 100. In addition, in order to make the description clear, the xyz three-dimensional orthogonal coordinate system is used in the figure for description. Usually the positive direction of the +z axis is vertically upward, and the xy plane is a horizontal plane. The y direction is the stacking direction of the battery cells. That is, in the battery module, multiple battery cells are stacked in the y direction. In addition, the up and down directions are relative directions and change appropriately according to the orientation of the battery pack 100.

[0016] The battery pack 100 includes a housing 20 and a battery module 10. The housing 20 is a substantially rectangular box in the xy plane view and contains the battery module 10. As described later, the housing 20 is separated into two upper and lower housings. Figure 1 The upper shell is omitted. Figure 1 In the embodiment, four battery modules 10 are housed in the housing 20. The four battery modules 10 are substantially the same size and are arranged side by side in the y direction. In the housing 20, a space for housing the battery modules 10 is referred to as a housing space 20a.

[0017] The battery module 10 has a plurality of battery cells 11. The battery cell 11 is a secondary battery such as a lithium-ion battery or a nickel-metal hydride battery. The battery cell 11 is a square battery having a roughly rectangular shape in the xz plane. An electrode body is housed inside the battery cell housing of the battery cell 11. The electrode body is formed, for example, by stacking a positive electrode and a negative electrode with a separator therebetween and then winding them into a cylindrical shape. The electrode body is not limited to a winding type, but may also be a stacked type. The electrode body is immersed in an electrolyte. In addition, the terminals of the positive and negative electrodes (not shown) are taken out from the upper surface or side of the battery cell 11. In the battery module 10, the terminals of the plurality of battery cells 11 are connected by a bus bar (not shown).

[0018] As described above, in each battery module 10, a plurality of battery cells 11 are stacked in the y direction. Each battery cell 11 has a safety valve 12. The safety valve 12 opens when the internal pressure of the battery cell 11 rises. That is, when gas, smoke, etc. (hereinafter collectively referred to as ejecta) is generated from the battery cell 11, the pressure in the internal space of the battery cell 11 rises. When the pressure in the internal space rises, the ejecta in the internal space is discharged to the outside of the battery cell 11 by opening the safety valve 12. In this way, safety can be improved.

[0019] Each battery cell 11 has a safety valve 12. The safety valve 12 is formed on the upper surface of the battery cell 11. A plurality of safety valves 12 are arranged in a row in one battery module 10. Specifically, in each battery module 10, a plurality of safety valves 12 are arranged in a row along the y direction. Here, since four battery modules 10 are provided, the safety valves 12 are arranged in four rows. In each battery module 10, the safety valve 12 is arranged in the central portion of the battery module 10 in the x direction.

[0020] The safety valve 12 is connected to the exhaust path 23 provided in the housing 20. That is, the exhaust path 23 is provided at a portion of the housing 20 that faces the safety valve 12. The exhaust path 23 includes a first path 23a provided along the y direction and a second path 23b provided along the x direction. The portion where the first path 23a and the second path 23b intersect is referred to as an intersection 23c.

[0021] The first path 23a is a portion arranged directly above the row of safety valves 12. Here, since four battery modules 10 are provided, the first paths 23a are arranged in four rows. Each first path 23a is arranged in the center of the battery module 10 in the x direction. The second path 23b is a portion connecting the plurality of first paths 23a and the exhaust valve 50. The second path 23b is formed to cross the plurality of first paths 23a along the x direction. The second path 23b is arranged in the center of the first path 23a in the y direction.

[0022] The ejection discharged from the safety valve 12 reaches the exhaust valve 50 through the first path 23a and the second path 23b. Thus, the exhaust valve 50 can discharge the ejection to the outside of the housing. Thus, the pressure rise inside the housing 20 can be suppressed. The exhaust valve 50 functions as a smoke exhaust valve for exhausting smoke generated from the battery cell 11. The exhaust valve 50 can be a safety valve that opens when the internal pressure of the housing 20 rises. In addition, an exhaust port can also be provided instead of the exhaust valve 50.

[0023] The buffer member 45 is disposed between two adjacent battery modules 10. That is, the battery modules 10 face each other via the buffer member 45. The buffer member 45 is a plate-shaped member formed of a resin having elasticity, etc. Thus, the impact received by the battery module 10 can be mitigated.

[0024] Next, use Figure 2 and Figure 3 , the structure of the exhaust path 23 and its surroundings will be described. Figure 2 yes Figure 1 The cross-sectional view taken along the II-II cutting line shows the structure in the xz plane. Figure 3 yes Figure 1 The cross-sectional view taken along the III-III cutting line shows the structure in the yz plane.

[0025] The housing 20 includes a first housing 21 and a second housing 22. The first housing 21 is an upper housing (UPR housing) disposed on the upper side of the battery cell 11. The second housing 22 is a lower housing (LWR housing) disposed on the lower side of the battery cell 11. The second housing 22 has a box-like shape with an upper side open. The first housing 21 has a box-like shape with a lower side open. The first housing 21 serves as a cover covering the upper side of the second housing 22.

[0026] The first housing 21 and the second housing 22 are formed of, for example, a metal material. For example, the first housing 21 and the second housing 22 are formed by stamping a metal plate or the like. The battery module 10 is accommodated in the housing 20 by covering the first housing 21 from the upper side with the battery module 10 arranged inside the second housing 22. In addition, after accommodating the battery module 10 in the housing 20, the first housing 21 and the second housing 22 may be fixed by welding or the like.

[0027] The first housing 21 has a protruding convex portion 25 on the upper side. The convex portion 25 is arranged just above the safety valve 12 to define the exhaust path 23. The space below the convex portion 25 becomes the exhaust path 23. In the xy plane view, the convex portion 25 is arranged at a position opposite to the safety valve 12. The convex portion 25 protrudes in a direction away from the battery cell 11. For example, the convex portion 25 can be formed on the first housing 21 by stamping a metal plate.

[0028] More specifically, the convex portion 25 includes a facing portion 25a and an inclined portion 25b. The facing portion 25a is a surface parallel to the xy plane. The inclined portion 25b is a surface inclined from the xy plane. In addition, in the first housing 21, the outer portion of the convex portion 25 is used as a retaining portion 26. The retaining portion 26 is a surface parallel to the xy plane and serves as a surface for retaining the battery module 10.

[0029] In the first path 23a, the facing portion 25a is located at a position facing the row of safety valves 12. The inclined portion 25b is a surface connecting the facing portion 25a and the holding portion 26. Thus, the inclined portions 25b are formed on both sides of the facing portion 25a. The inclined portion 25b is a tapered surface extending from the holding portion 26 toward the facing portion 25a in the +z direction. Therefore, the facing portion 25a is located on the +z side of the holding portion 26.

[0030] By providing the convex portion 25, the exhaust path 23 can be enlarged. Thus, even when a large amount of ejecta 60 is discharged, the exhaust path 23 can be prevented from being blocked. Therefore, the ejecta 60 can be efficiently discharged to the outside, and safety can be improved. The convex portion 25 can be formed by processing the metal plate. Therefore, the convex portion 25 functions as a rib that increases the rigidity of the first shell 21. Therefore, a thin metal plate can be used for lightweight. Moreover, the exhaust path 23 can be ensured without adding other components. The increase in the number of components can be suppressed. Thus, the exhaust path 23 can be formed by a simple structure, so the component cost can be reduced.

[0031] A sealing member 42 and a mica member 41 are arranged between the first housing 21 and the battery cell 11. The sealing member 42 is arranged between the mica member 41 and the first housing 21. The sealing member 42 is, for example, an elastic component. In addition, the sealing member 42 may also be an adhesive material. For example, the sealing member 42 may be a double-sided tape having elastic force in the thickness direction. The mica member 41 is formed of a mica material having excellent insulation and heat resistance. That is, the mica member 41 is an insulating material having excellent heat resistance.

[0032] The sealing member 42 is in contact with the first housing 21. In addition, the sealing member 42 is arranged to be in contact with the mica member 41. Therefore, the sealing member 42 can partition the exhaust path 23 formed by the convex portion 25. The sealing member 42 is arranged around the exhaust path 23 in a manner to partition the exhaust path 23. That is, the exhaust path 23 is partitioned from the housing space 20a.

[0033] Specifically, the sealing member 42 is disposed outside the convex portion 25 and surrounds the exhaust path 23. Figure 2 As shown in FIG. 1 , the sealing member 42 is disposed on both sides of the convex portion 25 forming the first path 23a in the x direction. Figure 3 As shown, the sealing member 42 is arranged on both sides of the convex portion 25 that becomes the second path 23b in the y direction. The sealing member 42 contacts the holding portion 26. The sealing member 42 seals the gap between the mica member 41 and the holding portion 26. Thus, the exhaust path 23 can be separated from the housing space 20a, so that the ejection from the safety valve 12 can be prevented from intruding into the housing space 20a in the housing 20. Thus, the ejection can be efficiently discharged from the exhaust valve 50.

[0034] Furthermore, by providing the convex portion 25 , the distance between the facing portion 25 a and the battery module 10 can be increased. That is, the distance from the safety valve 12 to the facing portion 25 a can be increased, so damage to the first housing 21 caused by the ejected matter 60 can be suppressed.

[0035] like Figure 2 As shown in FIG. 1 , in the xz plane view, the mica member 41 is L-shaped so as to cover the upper surface and the side surface of the battery cell 11. That is, the mica member 41 is bent so as to extend from the upper surface of the battery cell 11 to the side surface. The mica member 41 is arranged outside the portion that becomes the first path 23a. The sealing member 42 is in contact with the mica member 41. In addition, as shown in FIG. Figure 3 As shown in FIG. 2 , the mica member 41 is disposed directly below the second path 23 b and is in contact with the buffer member 45 .

[0036] In addition, the buffer member 45 includes a protrusion 45a that protrudes toward the first housing 21. Figure 3 As shown in FIG. 1 , the buffer member 45 has two protrusions 45a. The two protrusions 45a are arranged to be separated from each other in the y direction. Furthermore, the second path 23b is arranged between the two protrusions 45a.

[0037] The protrusion 45a is provided so as to be in contact with the holding portion 26. Even when a load is applied to the first housing 21 from above, deformation of the first housing 21 can be suppressed, thereby preventing the exhaust path 23 from being clogged.

[0038] In addition, the first path 23a of the plurality of battery modules 10 is connected to the exhaust valve 50 through the second path 23b. Thus, the opening of the exhaust valve can be controlled according to the pressure of the exhaust path 23. That is, when the pressure of the exhaust path 23 rises, the ejection 60 can be discharged to the outside of the housing 20. The ejection 60 can be discharged more appropriately.

[0039] Modifications

[0040] use Figure 4 , the structure of the battery pack 100 according to the modified example is described. Figure 4 2 is a cross-sectional view showing the structure of the first path 23a and its surroundings in the battery pack 100. Figure 4 In the embodiment, the battery pack 100 further includes a heat insulating member 46. The heat insulating member 46 is provided at a portion of the first housing 21 facing the exhaust path 23. Specifically, the heat insulating member 46 is a heat insulating sheet attached to the facing portion 25a. Therefore, the ejected matter ejected from the safety valve 12 collides with the heat insulating member 46.

[0041] For example, the smoke gas from the battery cell 11 may be a high temperature gas of 600° C. to 1000° C. Even when such a high temperature gas is generated, the temperature rise of the first housing 21 can be suppressed. Therefore, the temperature rise of the battery cells 11 other than the battery cell 11 whose valve is opened due to heat conduction of the first housing 21 can be prevented.

[0042] Construction Example 1

[0043] use Figure 5 , structural example 1 of the sealing member 42 is described. Figure 5 1 is an xz cross-sectional view showing the configuration of construction example 1. In construction example 1, the sealing member 42 is bonded to the first housing 21. Furthermore, the mica member 41 is mounted on the battery cell 11. That is, before the battery module 10 is stored, the sealing member 42 is integrated with the first housing 21. Then, the first housing 21 integrated with the sealing member 42 is covered from above the battery cell 11 to which the mica member 41 is mounted.

[0044] Since the mica component 41 is installed in the battery cell 11, the high-voltage terminal of the battery cell 11 can be protected in advance. Therefore, the safety during the assembly operation can be improved. In addition, the risk of conductive foreign matter adhering to the terminal portion can be suppressed. A component with elasticity can be used for the sealing component 42. Therefore, the sealing component 42 can be used as a buffer component for impacts from the upper side of the battery pack 100.

[0045] Construction Example 2

[0046] use Figure 6 , structural example 2 of the sealing member 42 is described. Figure 6 : is an xz cross-sectional view showing the structure of construction example 2. Figure 6 In the embodiment, the first case 21, the sealing member 42 and the mica member 41 are integrated. For example, the sealing member 42 is a double-sided tape. Therefore, before the battery module 10 is stored, the sealing member 42 can integrate the first case 21 and the mica member 41.

[0047] In the second structural example, the operation of fixing the mica member 41 to the battery cell 11 can be omitted. Furthermore, the operation of removing the mica member 41 from the battery cell 11 can be reduced when disassembling the battery pack 100. Thus, the number of components and the number of processes can be reduced, thereby improving productivity. Furthermore, the rigidity of the first shell 21 based on the mica member 41 can be improved. In addition, since the positional deviation of the mica member 41 and the first shell 21 can be ignored, the seal leakage caused by the positional deviation can be suppressed.

[0048] A check valve may be provided in the exhaust path 23. By providing a check valve, it is possible to prevent the ejected matter from flowing back from the safety valve. For example, a check valve may be provided at the intersection of the first path 23a and the second path 23b. It is possible to prevent the ejected matter from intruding into the first path 23a corresponding to the battery module 10 whose safety valve is not open.

[0049] Furthermore, a rectifying fin may also be provided in the exhaust path 23. The rectifying fin is provided in such a manner that the ejected matter flows toward the exhaust valve 50. For example, a rectifying fin may also be provided at the intersection of the first path 23a and the second path 23b. Preferably, the rectifying fin extends in the -x direction and is inclined toward the center side of the battery module 10 in the y direction. Thus, the ejected matter can be efficiently guided to the exhaust valve 50.

[0050] In addition, the present disclosure is not limited to the above-described embodiment, and can be appropriately modified within a scope not departing from the gist.

Claims

1. A battery pack comprising: A battery module comprising a battery cell, wherein the battery cell has a safety valve that opens when internal pressure increases, and the battery module is formed by stacking a plurality of the battery cells in a first direction; A housing for accommodating the battery module; an exhaust path provided in the housing along the first direction and arranged at a position opposite to the safety valve in the second direction; as well as The sealing member is provided between the housing and the battery module and is arranged around the exhaust path so as to partition the exhaust path.

2. The battery pack according to claim 1, The battery pack further includes a heat insulating member provided at a portion of the case facing the exhaust path.

3. The battery pack according to claim 1 or 2, The housing includes a convex portion protruding in a direction away from the battery module. The sealing member is provided on the outer side of the convex portion so that the convex portion forms an exhaust path.

4. The battery pack according to claim 1 or 2, The housing further includes an exhaust valve connected to the exhaust path. The plurality of battery modules are arranged in a third direction. The exhaust path comprises: a plurality of first paths provided along the first direction, and arranged so that one first path faces the safety valve of the battery cell included in one of the battery modules; and The second path is provided along the third direction and connects the plurality of first paths and the exhaust valve.

5. The battery pack according to claim 4, The battery pack is provided with a plurality of battery modules. A buffer member is provided between adjacent battery modules. The buffer member includes a protrusion on the outer side of the second path, the protrusion protruding toward the housing so as to come into contact with the housing.

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