Battery pack

Abstract

A battery pack (10) is provided with: a housing body (200) that defines a housing space (250) in which a battery module (100) is housed, a central internal space (260) through which gas generated from the housing space (250) passes, and a plurality of large communication holes (270L) and a plurality of small communication holes (270S) that communicate the housing space (250) and the central internal space (260) with each other; and a pressure relief valve (280) for discharging gas from the central internal space (260) to the external space. The length of a central inner space (260) between the pressure relief valve (280) and each large communication hole (270L) is longer than the length of a central inner space (260) between the pressure relief valve (280) and each small communication hole (270S).

Description

Technical Field

[0001] The present invention relates to batteries. Background Art

[0002] In recent years, battery packs have been developed for various applications such as automobiles. The battery pack includes at least one battery module and a housing that houses the at least one module.

[0003] An example of a battery pack is described in Patent Document 1. In this battery pack, a housing has a gas passage through which gas generated from a battery module passes.

[0004] Prior Art Literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Publication No. 2022-515674 Summary of the invention

[0007] -Problems to be solved by the invention-

[0008] For example, as described in Patent Document 1, gas generated from a battery module may be discharged from a container. The gas may reach a relatively high temperature. If the high-temperature gas is simply discharged from the container, it may be difficult to suppress the influence on people and components around the container.

[0009] One example of the purpose of the present invention is to suppress the temperature of the gas exhausted from the container. Other purposes of the present invention will become clear from the description of this specification.

[0010] -Methods for solving the problem-

[0011] One embodiment of the present invention is as follows.

[0012] [1] A battery pack, characterized in that it comprises: a battery module; a housing defining a housing space for housing the battery module, an internal space for allowing gas generated from the housing space to pass, and a plurality of connecting holes for connecting the housing space and the internal space to each other; and a gas exhaust portion for exhausting the gas from the internal space to an external space, wherein a length of the internal space between the gas exhaust portion and at least one connecting hole is longer than a length of the internal space between the gas exhaust portion and at least one other connecting hole that is smaller than the at least one connecting hole.

[0013] [2] The battery pack according to [1], wherein the housing defines another internal space located at least in part around the internal space.

[0014] [3] The battery pack according to [2], further comprising a fastener for fastening predetermined portions of the housing to each other, wherein at least a portion of the fastener enters the other internal space.

[0015] [4] A battery pack, characterized in that it comprises: a battery module; a housing that defines a housing space for housing the battery module and an internal space for allowing gas generated from the housing space to pass; and a cooling structure located at least in a portion of the periphery of the internal space of the housing for cooling the gas.

[0016] [5] The battery pack according to [4], wherein the cooling structure has another internal space.

[0017] [6] The battery pack according to [4] or [5], further comprising a fastener for fastening predetermined portions of the housing to each other, wherein at least a portion of the fastener enters the cooling structure.

[0018] -Effects of the Invention-

[0019] According to the above aspect of the present invention, the temperature of the gas exhausted from the container can be suppressed. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a perspective view of a battery pack according to an embodiment.

[0021] Figure 2 This is a plan view of a battery pack according to the embodiment with an upper case removed.

[0022] Figure 3 It is a plan view of a part of the battery pack according to the embodiment.

[0023] Figure 4 is Figure 3 An inner side view of the side frame as viewed from arrow A in FIG.

[0024] Figure 5 is Figure 3 An inner side view of the side frame as viewed from arrow B in FIG.

[0025] Figure 6 It is along Figure 3 A cross-sectional view of a portion of the battery pack along line CC.

[0026] Figure 7 It is along Figure 3 A cross-sectional view of a portion of the battery pack taken along line DD. DETAILED DESCRIPTION

[0027] Hereinafter, the embodiments of the present invention will be described using the drawings. In all the drawings, the same components are denoted by the same reference numerals, and the description thereof will be appropriately omitted.

[0028] Figure 1 It is a perspective view of the battery pack 10 according to the embodiment. Figure 2 It is a plan view of the battery pack 10 according to the embodiment in a state where the upper case 220 is removed.

[0029] In the embodiment, the battery pack 10 is mounted on a car. Specifically, the battery pack 10 is mounted between the front wheels and the rear wheels of the car. Hereinafter, unless otherwise specified, the battery pack 10 is described as being mounted on a car. However, the battery pack 10 can also be applied to purposes other than cars.

[0030] In each figure, the X direction, Y direction, and Z direction are shown for the purpose of explanation. The X direction indicates the front-rear direction of the battery pack 10. The Y direction is orthogonal to the X direction. The Y direction indicates the left-right direction of the battery pack 10. The Z direction is orthogonal to both the X direction and the Y direction. The Z direction indicates the up-down direction of the battery pack 10. The arrows indicating the X direction, the Y direction, and the Z direction indicate the front direction, the left direction, and the up direction of the battery pack 10, respectively. Figure 2 However, the relationship between the X, Y and Z directions and the front-rear, left-right and up-down directions of the battery pack 10 is not limited to this example.

[0031] In the embodiment, the front-rear direction, left-right direction, and up-down direction of the battery pack 10 are determined by the vehicle on which the battery pack 10 is mounted. The X direction, the Y direction, and the Z direction respectively indicate the front-rear direction, the left-right direction, and the up-down direction of the vehicle. The arrow indicating the X direction, the arrow indicating the Y direction, and the arrow indicating the Z direction respectively indicate the front direction, the left direction, and the up-down direction of the vehicle. However, the relationship between the front-rear direction, the left-right direction, and the up-down direction of the battery pack 10 and the front-rear direction, the left-right direction, and the up-down direction of the vehicle is not limited to this example.

[0032] Hereinafter, the direction perpendicular to the Z direction will be referred to as a horizontal direction as necessary.

[0033] The battery pack 10 includes four battery modules 100 and a housing 200. The four battery modules 100 include a pair of battery modules 100 on the left side arranged in the X direction and a pair of battery modules 100 on the right side arranged in the X direction. The housing 200 includes a lower housing 210 and an upper housing 220. The lower housing 210 is also generally referred to as a tray or a main body. The lower housing 210 includes a lower plate 212 and a side frame 214. The upper housing 220 is also generally referred to as a cover or a lid.

[0034] Each battery module 100 has a plurality of battery cells stacked in a horizontal direction. For example, in each battery module 100, a plurality of battery cell groups including a plurality of battery cells connected in parallel are connected in series. Alternatively, a plurality of single battery cells may be connected in series.

[0035] A pair of terminals 110 are provided in front of the side frame 214. The pair of terminals 110 are arranged substantially parallel to the Y direction. The front end of each terminal 110 protrudes forward from the front surface of the side frame 214. In the electrical path, between the pair of terminals 110, four battery modules 100 are connected in series.

[0036] The lower case 210 and the upper case 220 are mounted to each other via a seal 230. The lower case 210, the upper case 220, and the seal 230 form a housing space 250. The housing space 250 houses four battery modules 100.

[0037] The lower plate 212 defines the bottom of the storage space 250. The side frame 214 defines the side portion of the storage space 250. Specifically, when viewed from the Z direction, the side frame 214 is disposed along the outermost periphery of the lower plate 212. The upper housing 220 defines the top of the storage space 250.

[0038] The seal 230 is, for example, an elastic material such as rubber. When viewed from the Z direction, the seal 230 is provided over the entire circumference of the side frame 214. Thus, when viewed from the Z direction, the seal 230 surrounds the storage space 250. Therefore, the storage space 250 can be sealed from the space outside the storage body 200 by the seal 230.

[0039] The number and arrangement of the battery modules are not limited to the examples described in the embodiments. For example, the number of the battery modules 100 may be only two, only three, or five or more.

[0040] Figure 3 It is a plan view of a portion of the battery pack 10 according to the embodiment. Figure 4 is Figure 3 FIG. 2 is an inner side view of the side frame 214 as viewed from arrow A. FIG. Figure 5 is Figure 3 FIG. 2 is an inner side view of the side frame 214 as viewed from arrow B. FIG. Figure 6 It is along Figure 3 1 is a cross-sectional view of a portion of the battery pack 10 taken along line CC. Figure 7 It is along Figure 3 A cross-sectional view of a portion of the battery pack 10 taken along line DD. Figure 3 , Figure 6 as well as Figure 7In order to simplify the description, the battery module 100 accommodated in the accommodation space 250 is not shown.

[0041] Reference Figure 6 as well as Figure 7 , the fastening structure between the lower plate 212 and the side frame 214 and the fastening structure between the lower plate 212 and the upper shell 220 are described.

[0042] like Figure 6 As shown, the outer peripheral portion of the lower plate 212 and the lower portion of the side frame 214 are fastened to each other by lower bolts 242. For example, the lower bolts 242 are fastened to nuts provided on the side frame 214. In the embodiment, when viewed from the Z direction, a plurality of lower bolts 242 are provided over the entire circumference of the side frame 214. However, the number of lower bolts 242 provided over the entire circumference of the side frame 214 may be only one. The fasteners that fasten the lower plate 212 and the side frame 214 to each other are not limited to the lower bolts 242. As the fasteners, not only bolts but also screws are exemplified.

[0043] like Figure 6 As shown, the upper portion of the side frame 214 and the outer peripheral portion of the upper housing 220 are fastened to each other by upper bolts 244 via a seal 230. Figure 6 In the example shown, the upper bolt 244 penetrates the seal 230 substantially parallel to the Z direction. For example, the upper bolt 244 is fastened to a nut provided on the side frame 214. In the embodiment, a plurality of upper bolts 244 are provided over the entire circumference of the side frame 214 as viewed from the Z direction. However, the number of upper bolts 244 provided over the entire circumference of the side frame 214 may be only one. The fasteners that fasten the side frame 214 and the upper housing 220 to each other are not limited to the upper bolts 244. As the fasteners, not only bolts but also screws are exemplified.

[0044] Reference Figure 3 to Figure 7 , the side frame 214 is described. The side frame 214 defines a central internal space 260, a lower internal space 262, an upper internal space 264, a plurality of large communication holes 270L, and a plurality of small communication holes 270S. Figure 3 as well as Figure 7 As shown, a plurality of pressure release valves 280 are provided on the outer side of the side frame 214 .

[0045] like Figure 6 as well as Figure 7As shown, the central internal space 260 is located substantially at the center of the side frame 214 in the Z direction. When viewed from the Z direction, the central internal space 260 extends over at least a portion of the entire circumference of the side frame 214. In an embodiment, when viewed from the Z direction, the central internal space 260 extends continuously between the area indicated by the arrow A of the side frame 214 and the area indicated by the arrow B of the side frame 214. In an embodiment, when viewed from the Z direction, the central internal space 260 may be partially interrupted except between the area indicated by the arrow A of the side frame 214 and the area indicated by the arrow B of the side frame 214.

[0046] The housing space 250 and the central internal space 260 are connected to each other via a plurality of large communication holes 270L and a plurality of small communication holes 270S. The central internal space 260 allows gas generated from the housing space 250 to pass through. For example, under given conditions such as charging and discharging of the battery module 100, high-temperature gas may be generated from the battery module 100. The central internal space 260 allows the high-temperature gas generated from the housing space 250 to pass through, for example. However, the example of the gas passing through the central internal space 260 is not limited to the high-temperature gas.

[0047] The gas generated from the storage space 250 enters the central internal space 260 through the plurality of large communication holes 270L and the plurality of small communication holes 270S. Figure 3 The size of each small communicating hole 270S observed by the arrow B shown is smaller than Figure 3 The size of each large communicating hole 270L is observed by arrow A shown in FIG. Figure 4 As shown, when viewed from arrow A, each large communicating hole 270L is substantially quadrilateral in shape. Figure 5 As shown, when viewed from arrow B, each small communicating hole 270S is roughly quadrilateral in shape. However, the shape of each large communicating hole 270L and the shape of each small communicating hole 270S are not limited to this example. When the pressure inside the central internal space 260 exceeds a certain value due to the generation of gas from the containing space 250, etc., each pressure release valve 280 is actuated, and the gas is discharged to the external space through each pressure release valve 280. In this way, the pressure release valve 280 acts as a gas discharge unit. In addition, the gas discharge unit that discharges the gas passing through the central internal space 260 to the external space is not limited to the pressure release valve 280.

[0048] like Figure 6 as well as Figure 7As shown, the lower internal space 262 is located below the central internal space 260. In the embodiment, the lower internal space 262 is a hollow space. Therefore, the lower internal space 262 can function as a cooling structure for cooling the gas passing through the central internal space 260. Therefore, the temperature of the gas discharged from the pressure release valve 280 via the central internal space 260 can be suppressed. Furthermore, when the lower internal space 262 is a hollow space, the side frame 214 can be made lighter than when the lower internal space 262 is solid.

[0049] like Figure 6 As shown, the front end of the lower bolt 242 enters the lower internal space 262. The central internal space 260 and the lower internal space 262 are physically separated from each other by the lower partition wall 266 at least in a portion of the entire circumference of the side frame 214. Therefore, the front end of the lower bolt 242 can be less likely to be affected by the high-temperature gas passing through the central internal space 260. The lower partition wall 266 can also be partially interrupted on the entire circumference of the side frame 214. For example, the lower partition wall 266 can also be provided in a region overlapping with the lower bolt 242 in the Z direction, rather than being provided in at least a portion of a region not overlapping with the lower bolt 242 in the Z direction.

[0050] The lower internal space 262 may be solidified by a refrigerant such as liquid. In this case, the lower internal space 262 may also function as a cooling structure for cooling the gas passing through the central internal space 260. In addition, the cooling structure is not limited to the lower internal space 262.

[0051] like Figure 6 as well as Figure 7 As shown, the upper internal space 264 is located above the central internal space 260. In the embodiment, the upper internal space 264 is a hollow space. Therefore, the upper internal space 264 can function as a cooling structure for cooling the gas passing through the central internal space 260. Therefore, the temperature of the gas discharged from the pressure release valve 280 via the central internal space 260 can be suppressed. Similar to the lower internal space 262, the upper internal space 264 can also be solid by a refrigerant such as a liquid.

[0052] like Figure 6As shown, the front end of the upper bolt 244 enters the upper internal space 264. The central internal space 260 and the upper internal space 264 are physically separated from each other by the upper partition wall 268 at least in a portion of the entire circumference of the side frame 214. Therefore, the front end of the upper bolt 244 can be less susceptible to the high-temperature gas passing through the central internal space 260. The upper partition wall 268 can also be partially interrupted in the entire circumference of the side frame 214. For example, the upper partition wall 268 can also be provided in a region overlapping with the upper bolt 244 in the Z direction, rather than being provided in at least a portion of a region not overlapping with the upper bolt 244 in the Z direction.

[0053] The cross-sections of the central internal space 260, the lower internal space 262, and the upper internal space 264 are not limited to Figure 6 as well as Figure 7 The cooling structure described above can be located at least in a portion of the periphery of the central internal space 260. For example, one of the lower internal space 262 and the upper internal space 264 may not exist. In addition, the central internal space 260 may be offset downward or upward from the approximate center of the side frame 214 in the Z direction.

[0054] like Figure 3 to Figure 7 As shown, in the embodiment, the length of the central internal space 260 between the pressure release valve 280 and each large communicating hole 270L is longer than the length of the central internal space 260 between the pressure release valve 280 and each small communicating hole 270S. Under given conditions such as charging and discharging of the battery module 100, particles are sometimes generated from the battery module 100 together with the high-temperature gas. The gas and the particles pass through the central internal space 260 together. In this case, the longer the period during which the gas and the particles pass through the central internal space 260, the more the temperature of the gas can be reduced by the particles. Therefore, compared with the temperature of the gas entering the central internal space 260 from the small communicating holes 270S, the temperature of the gas entering the central internal space 260 from the large communicating holes 270L is more easily reduced by the above-mentioned particles.

[0055] In the embodiment, when a relatively large amount of gas is generated from the storage space 250, the gas can be discharged through both the large communicating holes 270L and the small communicating holes 270S. In this case, due to the difference in size between each large communicating hole 270L and each small communicating hole 270S, the amount of gas entering the central internal space 260 from the large communicating holes 270L can be greater than the amount of gas entering the central internal space 260 from the small communicating holes 270S. Therefore, in the embodiment, by effectively lowering the temperature of the gas passing through the central internal space 260 using the above-mentioned particles, the temperature of the gas discharged from the pressure release valve 280 can be suppressed.

[0056] In the embodiment, when a relatively small amount of gas is generated from the accommodation space 250, the gas can be discharged mainly through the small communicating hole 270S rather than through the large communicating hole 270L. The length from the small communicating hole 270S to the central internal space 260 of the pressure release valve 280 is shorter than the length from the large communicating hole 270L to the central internal space 260 of the pressure release valve 280. Therefore, in the embodiment, a small amount of gas can be efficiently discharged from the pressure release valve 280 during the initial operation of the pressure release valve 280.

[0057] The connecting holes that connect the receiving space 250 and the central internal space 260 are not limited to the large connecting holes 270L and the small connecting holes 270S. For example, the sizes of the plurality of connecting holes may be the same. Figure 3 The area indicated by arrow A and Figure 3 A communicating hole is provided on one side of the area indicated by the arrow B.

[0058] Reference Figure 7 , the pressure relief valve 280 is described.

[0059] The pressure release valve 280 has a lower mounting surface 280 a and an upper mounting surface 280 b . The lower mounting surface 280 a and the upper mounting surface 280 b are mounted on the outer side surface of the side frame 214 .

[0060] At least a portion of the upper portion and at least a portion of the side portion of the pressure relief valve 280 are covered by an outer cover 282a. At least a portion of the lower portion of the pressure relief valve 280 is covered by an inner cover 282b. The lower end of the outer cover 282a and the lower end of the inner cover 282b define a discharge opening 282c. The discharge opening 282c opens toward the substantially lower portion of the pressure relief valve 280. Therefore, the gas discharged from the pressure relief valve 280 is discharged toward the substantially lower portion of the pressure relief valve 280 through the discharge opening 282c.

[0061] The inner cover 282b includes a shielding portion 282b1. At least a portion of the shielding portion 282b1 is located between the lower mounting surface 280a and the discharge opening 282c. Under given conditions such as washing a car equipped with the battery pack 10, there is a possibility that high-pressure water is ejected from the outside of the housing 200. In the embodiment, even if high-pressure water is ejected from the oblique lower side of the housing 200 toward the discharge opening 282c, the shielding portion 282b1 can function as a structure that prevents the water from being ejected directly onto the lower mounting surface 280a.

[0062] As mentioned above, although embodiment of this invention was described with reference to drawings, these are illustrations of this invention, and various structures other than the above-mentioned can also be adopted.

[0063] This application claims priority based on Japanese patent application No. 2022-139756 filed on September 2, 2022 and Japanese patent application No. 2022-139757 filed on September 2, 2022, and all of the disclosures are incorporated herein.

[0064] -Description of Reference Numerals-

[0065] 10: battery pack, 100: battery module, 110: terminal, 200: storage body, 210: lower shell, 212: lower plate, 214: side frame, 220: upper shell, 230: seal, 242: lower bolt, 244: upper bolt, 250: storage space, 260: central internal space, 262: lower internal space, 264: upper internal space, 266: lower partition wall, 268: upper partition wall, 270L: large connecting hole, 270S: small connecting hole, 280: pressure release valve, 280a: lower mounting surface, 280b: upper mounting surface, 282a: outer cover, 282b: inner cover, 282b1: shielding portion, 282c: discharge opening.

Claims

1. A battery pack, characterized in that: have: Battery modules; a housing body defining a housing space for housing the battery module, an internal space for allowing gas generated from the housing space to pass through, and a plurality of communication holes for connecting the housing space and the internal space to each other; as well as a gas discharge portion for discharging the gas from the internal space to the external space, The length of the internal space between the gas discharge portion and at least one communicating hole is longer than the length of the internal space between the gas discharge portion and at least one other communicating hole smaller than the at least one communicating hole.

2. The battery pack according to claim 1, wherein: The receiving body defines at least a portion of another inner space around the inner space.

3. The battery pack according to claim 2, wherein: The battery pack further comprises: a fastener for fastening predetermined portions of the housing to each other. At least a portion of the fastener enters the other interior space.

4. A battery pack, characterized in that: have: Battery modules; a housing body defining a housing space for housing the battery module and an inner space for allowing gas generated from the housing space to pass; and The cooling structure is located at least in a portion of the periphery of the internal space of the housing, and cools the gas.

5. The battery pack according to claim 4, wherein: The cooling structure has another interior space.

6. The battery pack according to claim 4 or 5, wherein: The battery pack further comprises: a fastener for fastening predetermined portions of the housing to each other. At least a portion of the fastener enters the cooling configuration.

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