Battery module

Abstract

To keep gas generated from a battery cell inside a battery module for a certain period without staying near the battery cell.SOLUTION: A battery module 10 includes a battery cell 100 and a first plate 510. The first plate 510 defines a hollow space HS existing between an internal space IS where the battery cell 100 exists and an external space ES existing outside the battery cell 100, and an internal hole 513 communicating between the hollow space HS and the internal space IS. The first plate 510 separates the hollow space HS and the external space ES from each other.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a battery module. [Background technology]

[0002] In recent years, various battery modules have been developed. A battery module includes battery cells and a housing that houses the battery cells.

[0003] Patent Document 1 describes a battery module. The battery module includes battery cells, a module case that houses the battery cells, and a gas venting structure formed on a side surface of the module case. The gas venting structure has a first partition wall and a second partition wall that is spaced from the first partition wall to the outside of the module case. The first partition wall includes a first gas venting hole and a first mesh structure that covers the first gas venting hole. The second partition wall includes a second gas venting hole and a second mesh structure that covers the second gas venting hole. The first gas venting hole and the second gas venting hole are arranged in areas that do not face each other. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Special Publication No. 2023-513503 Summary of the Invention [Problem to be solved by the invention]

[0005] In a battery module, a relatively high-temperature gas may be generated from a battery cell due to an abnormality in the battery cell. To prevent the temperature of the battery cell from rising further, it is desirable to prevent the gas generated from the battery cell from accumulating near the battery cell. On the other hand, if the gas generated from the battery cell is immediately discharged from the battery module, the gas may affect devices, elements, or components around the battery module.

[0006] One example of an object of the present invention is to keep gas generated from a battery cell inside the battery module for a certain period of time without allowing the gas to remain near the battery cell. Other objects of the present invention will become apparent from the description of this specification. [Means for solving the problem]

[0007] One aspect of the present invention is as follows. 1. A battery cell; a structure that defines a hollow space between one space in which the battery cell is located and another space located outside the battery cell, and a hole that connects the hollow space and the one space to each other; Equipped with The structure isolates the hollow space and the other space from each other. 2. The battery module according to claim 1, wherein the structure defines a plurality of the holes. 3. A battery module according to 1. or 2., wherein the hollow space is open at least on one of its ends in a direction perpendicular to the direction connecting the one space and the other space. [Effects of the Invention]

[0008] According to the above aspect of the present invention, gas generated from the battery cells can be retained inside the battery module for a certain period of time without being retained near the battery cells. [Brief explanation of the drawings]

[0009] [Figure 1]FIG. 2 is an exploded top perspective view of the battery module according to the embodiment. [Figure 2] FIG. 4 is a front view of a portion of the first plate according to the embodiment. [Figure 3] FIG. 2 is a side view of a battery cell and a first plate according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings, similar components are designated by similar reference numerals, and the description thereof will be omitted as appropriate.

[0011] FIG. 1 is an exploded perspective view of a battery module 10 according to an embodiment.

[0012] For the sake of explanation, FIG. 1 shows the X, Y, and Z directions. The X direction indicates the front-rear direction of the battery module 10. The Y direction is one of the directions perpendicular to the X direction. The Y direction indicates the left-right direction of the battery module 10. The Z direction is a direction perpendicular to both the X and Y directions. The Z direction indicates the up-down direction of the battery module 10. The arrows pointing to the X direction, the Y direction, and the Z direction indicate the rear, right, and up directions of the battery module 10, respectively. Hereinafter, as necessary, the tip side of the arrow indicating the X direction will be referred to as the +X side, the opposite side of the tip of the arrow indicating the X direction will be referred to as the -X side, the tip side of the arrow indicating the Y direction will be referred to as the +Y side, the opposite side of the tip of the arrow indicating the Y direction will be referred to as the -Y side, the tip side of the arrow indicating the Z direction will be referred to as the +Z side, and the opposite side of the tip of the arrow indicating the Z direction will be referred to as the -Z side. The relationship between the X direction, Y direction, and Z direction and the front-rear direction, left-right direction, and up-down direction of the battery module 10 is not limited to the above example.

[0013] The battery module 10 includes a plurality of battery cells 100, a plurality of compression pads 200, a first voltage detection device 300, a second voltage detection device 400, a module housing 500, a positive bus bar 610, and a negative bus bar 620.

[0014] The multiple battery cells 100 and the multiple compression pads 200 are stacked alternately in the Y direction. Each compression pad 200 is disposed between adjacent battery cells 100 in the Y direction. Hereinafter, unless otherwise specified, a stack of battery cells 100 refers to the multiple battery cells 100 and the multiple compression pads 200 stacked alternately in the Y direction. The dimension of each battery cell 100 in the X direction is the dimension in the longitudinal direction of each battery cell 100. The dimension of each battery cell 100 in the Z direction is the dimension in the lateral direction of each battery cell 100. The dimension of each battery cell 100 in the Y direction is the dimension in the thickness direction of each battery cell 100. The shape of each battery cell 100 is not limited to this example.

[0015] Each battery cell 100 includes a battery element (not shown), an outer casing 110, a positive electrode terminal 122, and a negative electrode terminal 124. In one example, the battery element includes a plurality of positive electrodes and a plurality of negative electrodes (not shown) stacked alternately in the Y direction, and a separator (not shown) positioned between adjacent positive electrodes and negative electrodes in the Y direction. The outer casing 110 seals the battery element and an electrolyte (not shown). The positive electrode terminal 122 is electrically connected to the positive electrode of the battery element. The positive electrode terminal 122 is drawn out from one of both sides of the outer casing 110 in the X direction. The negative electrode terminal 124 is electrically connected to the negative electrode of the battery element. The negative electrode terminal 124 is drawn out from the other side of the outer casing 110 in the X direction. However, the structure of each battery cell 100 is not limited to this example.

[0016] Each battery cell 100 may be an all-solid-state battery. In an all-solid-state battery, a solid electrolyte layer is provided in the portion corresponding to the separator. An all-solid-state battery does not contain an electrolyte solution. Hereinafter, unless otherwise specified, each battery cell 100 will be described as a battery cell containing an electrolyte solution.

[0017] The multiple battery cells 100 are electrically connected in a combination of series and parallel. Specifically, cell groups including at least two battery cells 100 adjacent to each other in the Y direction and connected in parallel are stacked in the Y direction and connected in series. A terminal group 120 including a positive terminal 122 drawn from a battery cell 100 of one cell group connected in parallel and a negative terminal 124 drawn from a battery cell 100 of another cell group connected in parallel is located on the -X side of the stack of battery cells 100. The positive terminal 122 and the negative terminal 124 in the terminal group 120 are electrically connected to each other by a joining method such as laser welding. A terminal group 120 is also located on the +X side of the stack of battery cells 100. Thus, multiple cell groups are connected in series from a cell group located at one end of the stack of battery cells 100 in the Y direction to a cell group located at the other end of the stack of battery cells 100 in the Y direction. Hereinafter, unless otherwise specified, the -X side terminal group 120 refers to the terminal group 120 located on the -X side of the stack of battery cells 100, and the +X side terminal group 120 refers to the terminal group 120 located on the +X side of the stack of battery cells 100.

[0018] The electrical connection of the plurality of battery cells 100 is not limited to the above example. For example, the cell group may include three or more battery cells 100 connected in parallel. Alternatively, a stack of battery cells 100 may be formed by connecting single battery cells 100 in series.

[0019] The first voltage detecting device 300 detects the voltages of the plurality of −X side terminal groups 120. The first voltage detecting device 300 has a first holding body 310, a plurality of first voltage detecting terminals 320, and a first connector 340.

[0020] The first holder 310 covers the -X side portion of the stack of battery cells 100. The first holder 310 is, for example, an insulator such as resin. The first holder 310 defines a plurality of first openings 311. Each of the plurality of -X side terminal groups 120 is exposed toward the -X side through each of the plurality of first openings 311.

[0021] Each of the multiple first voltage detection terminals 320 is located on the -X side with respect to each of the multiple -X side terminal groups 120. Each first voltage detection terminal 320 is made of a conductor such as metal. The +X side surface of each first voltage detection terminal 320 and the -X side surface of each -X side terminal group 120 are joined to each other by a joining method such as laser welding. Therefore, each first voltage detection terminal 320 and each -X side terminal group 120 are electrically connected to each other. Therefore, the first voltage detection device 300 can detect the voltage of each -X side terminal group 120 using each first voltage detection terminal 320. The multiple first voltage detection terminals 320 are integrally held by a first holder 310. Therefore, by placing the first holder 310 at an appropriate position with respect to the stack of battery cells 100, each of the multiple first voltage detection terminals 320 can be positioned appropriately with respect to each of the multiple -X side terminal groups 120.

[0022] The first connector 340 is provided on the first holding body 310. The multiple first voltage detection terminals 320 and the first connector 340 are electrically connected to each other via multiple voltage detection lines not shown in Fig. 1. The multiple voltage detection lines are routed between the first voltage detection terminals 320 and the first connector 340 via the first holding body 310.

[0023] The second voltage detecting device 400 detects the voltages of the plurality of +X side terminal groups 120. The second voltage detecting device 400 has a second holding body 410 and a plurality of second voltage detecting terminals 420.

[0024] The second holder 410 covers the +X side portion of the stack of battery cells 100. The second holder 410 is, for example, an insulator such as resin. The second holder 410 defines a plurality of second openings 411. Each of the multiple +X side terminal groups 120 is exposed toward the +X side through each of the multiple second openings 411.

[0025] Each of the multiple second voltage detection terminals 420 is located on the +X side with respect to each of the multiple +X side terminal groups 120. Each second voltage detection terminal 420 is made of a conductor such as metal. The -X side surface of each second voltage detection terminal 420 and the +X side surface of each +X side terminal group 120 are joined to each other by a joining method such as laser welding. Therefore, each second voltage detection terminal 420 and each +X side terminal group 120 are electrically connected to each other. Therefore, the second voltage detection device 400 can detect the voltage of each +X side terminal group 120 using each second voltage detection terminal 420. The multiple second voltage detection terminals 420 are integrally held by a second holder 410. Therefore, by placing the second holder 410 at an appropriate position with respect to the stack of battery cells 100, each of the multiple second voltage detection terminals 420 can be positioned at an appropriate position with respect to each of the multiple +X side terminal groups 120.

[0026] Similar to the first voltage detection device 300, the multiple second voltage detection terminals 420 and a connector not shown in FIG. 1 are electrically connected to each other via multiple voltage detection lines not shown in FIG. 1.

[0027] The module housing 500 includes a first plate 510, a second plate 520, a third plate 530, a fourth plate 540, a fifth plate 550, and a sixth plate 560. Each plate is, for example, a conductor such as a metal.

[0028] The first plate 510 covers the -X side portion of the stack of battery cells 100 with the first voltage detection device 300 positioned between the stack of battery cells 100 and the first plate 510. The second plate 520 covers the +X side portion of the stack of battery cells 100 with the second voltage detection device 400 positioned between the stack of battery cells 100 and the second plate 520. The third plate 530 covers the -Y side portion of the stack of battery cells 100 with the first insulating cover 532 positioned between the stack of battery cells 100 and the third plate 530. The first insulating cover 532 can electrically insulate the battery cell 100 located at one end on the -Y side from the third plate 530. The first insulating cover 532 is made of, for example, silica aerogel. The fourth plate 540 covers the +Y side portion of the stack of battery cells 100, with the second insulating cover 542 positioned between the stack of battery cells 100 and the fourth plate 540. The second insulating cover 542 electrically insulates the battery cell 100 located at the other end of the +Y side from the fourth plate 540. The second insulating cover 542 is made of, for example, silica aerogel. The fifth plate 550 covers the -Z side portion of the stack of battery cells 100, with the thermally conductive adhesive 552 positioned between the stack of battery cells 100 and the fifth plate 550. The thermally conductive adhesive 552 allows heat generated from the stack of battery cells 100 to dissipate toward the fifth plate 550. The sixth plate 560 covers the +Z side portion of the stack of battery cells 100.

[0029] The positive electrode bus bar 610 is located at the end of the first holder 310 on the -Y side. The positive electrode bus bar 610 and the -X side positive electrode terminal 122 of the cell group including the multiple battery cells 100 located at one end on the -Y side are joined to each other by a joining method such as laser welding. Therefore, the positive electrode bus bar 610 and the cell group located at one end on the -Y side are electrically connected to each other. The positive electrode bus bar 610 functions as an external terminal for electrically connecting the battery module 10 to an external device such as another battery module.

[0030] The negative electrode bus bar 620 is located at the end of the first holder 310 on the +Y side. The negative electrode bus bar 620 and the negative electrode terminal 124 on the -X side of the cell group including the plurality of battery cells 100 located at the other end on the +Y side are joined to each other by a joining method such as laser welding. Therefore, the negative electrode bus bar 620 and the cell group located at the other end on the +Y side are electrically connected to each other. The negative electrode bus bar 620 functions as an external terminal for electrically connecting the battery module 10 to an external device such as another battery module.

[0031] 1 , the positive electrode terminal 122 at the end of a plurality of serially connected cell groups is the positive electrode terminal 122 on the -X side of the cell group located at one end on the -Y side, and the negative electrode terminal 124 at the end of a plurality of serially connected cell groups is the negative electrode terminal 124 on the -X side of the cell group located at the other end on the +Y side. Thus, the positive electrode bus bar 610 is disposed on both the -X side and the -Y side of the stack of battery cells 100, and the negative electrode bus bar 620 is disposed on both the -X side and the +Y side of the stack of battery cells 100. However, the arrangement of the positive electrode terminal 122 and the negative electrode terminal 124 at the end of a plurality of serially connected cell groups may differ depending on the number of cell groups included in the stack of battery cells 100. For example, there are cases where the positive electrode terminal 122 at the end of a group of multiple cells connected in series is the positive electrode terminal 122 on the -X side of the cell group located at one end on the -Y side, and the negative electrode terminal 124 at the end of a group of multiple cells connected in series is the negative electrode terminal 124 on the +X side of the cell group located at the other end on the +Y side. In this case, the positive electrode bus bar 610 is arranged on the -X side and the -Y side of the stack of battery cells 100, and the negative electrode bus bar 620 is arranged on the +X side and the +Y side of the stack of battery cells 100.

[0032] Fig. 2 is a front view of a portion of a first plate 510 according to an embodiment. Fig. 3 is a side view of a battery cell 100 and a first plate 510 according to an embodiment. In Fig. 3, the position of the internal hole 513 of the plate main body portion 512 is surrounded by a dashed line. In Fig. 2, a white circle with an X indicating the X direction indicates that the arrow indicating the X direction extends from the front to the back of the page. In Fig. 3, a white circle with an X indicating the Y direction indicates that the arrow indicating the Y direction extends from the front to the back of the page.

[0033] As shown in FIGS. 2 and 3 , the first plate 510 according to the embodiment includes a plate main body 512, a pair of protrusions 514, and a connecting portion 516. The plate main body 512, the pair of protrusions 514, and the connecting portion 516 are, for example, integrally molded. The plate main body 512 has a generally plate shape perpendicular to the X direction. The pair of protrusions 514 are located on the −X side surface of the plate main body 512. The pair of protrusions 514 are aligned in the Z direction. Each protrusion 514 has a generally plate shape perpendicular to the Z direction. The connecting portion 516 connects the −X side ends of the pair of protrusions 514 to each other. The connecting portion 516 has a generally plate shape perpendicular to the X direction. The +Z side end of the connecting portion 516 and the −X side end of the +Z side protrusion 514 are connected to each other. The −Z side end of the connecting portion 516 and the −X side end of the −Z side protrusion 514 are connected to each other.

[0034] As shown in FIG. 3, the first plate 510 has a structure that defines a hollow space HS that is surrounded in the Y direction by a plate main body 512, a pair of protrusions 514, and a connecting portion 516. The hollow space HS exists between an internal space IS in which the multiple battery cells 100 are located, and an external space ES that is located outside the multiple battery cells 100. In FIG. 3, the X direction is the direction that connects the internal space IS and the external space ES. The hollow space HS extends in the Y direction. As shown in FIG. 3, the hollow space HS has a substantially rectangular shape when viewed from the Y direction. However, the shape of the hollow space HS is not limited to the example shown in FIG. 3.

[0035] 2 and 3, the plate main body 512 defines a plurality of internal holes 513. Each internal hole 513 penetrates the plate main body 512 in the X direction. The multiple internal holes 513 are located on the +X side of the hollow space HS of the plate main body 512. The multiple internal holes 513 connect the hollow space HS and the internal space IS to each other.

[0036] As shown in FIG. 2, the multiple internal holes 513 are spaced apart from one another and aligned in the Y direction. Therefore, the strength of the plate main body 512 can be increased compared to when a single internal hole 513 continuous in the Y direction is provided instead of the multiple internal holes 513 aligned in the Y direction. However, a single internal hole 513 continuous in the Y direction may be provided instead of the multiple internal holes 513 aligned in the Y direction. In the example shown in FIG. 2, each internal hole 513 has a substantially rectangular shape having a pair of long sides extending in the Y direction and a pair of short sides extending in the Z direction. In the example shown in FIG. 2, the center of each internal hole 513 is located at the center of the plate main body 512 in the Z direction when viewed from the X direction. However, the shape and position of each internal hole 513 are not limited to the example shown in FIG. 2.

[0037] 2 and 3, the connecting portion 516 does not define a hole that connects the hollow space HS and the external space ES to each other, and therefore the connecting portion 516 physically isolates the hollow space HS and the external space ES from each other.

[0038] An abnormality in the battery cell 100 may cause relatively high-temperature gas to be generated from the battery cell 100. In the embodiment, at least a portion of the gas generated from the battery cell 100 passes through the multiple internal holes 513 and enters the hollow space HS. Therefore, compared to a case where the multiple internal holes 513 are not provided, it is possible to prevent the high-temperature gas generated from the battery cell 100 from accumulating near the battery cell 100. Therefore, compared to a case where the gas is likely to accumulate near the battery cell 100, it is possible to suppress a further increase in the temperature of the battery cell 100. In the embodiment, the hollow space HS and the external space ES are physically isolated from each other by the connecting portion 516. Therefore, the gas that has entered the hollow space HS can be retained inside the hollow space HS for a certain period of time without passing through the connecting portion 516. Therefore, compared to a case where the high-temperature gas generated from the battery cell 100 is immediately discharged from the battery module 10, it is possible to lower the temperature of the gas inside the hollow space HS and prevent the gas generated from the battery cell 10 from affecting devices, elements, or components around the battery module 10. For example, in the embodiment, even if a pack bus bar that electrically connects a plurality of battery modules 10 to each other is located at the destination of gas discharge from the battery module 10, melting of the insulating coating of the pack bus bar can be suppressed, and a short circuit between the pack bus bar and a conductor such as the module housing 500 around the pack bus bar can be suppressed. Furthermore, in the embodiment, even if another battery module 10 is located at the destination of gas discharge from the battery module 10, a chain reaction of abnormalities caused by the gas to the other battery modules 10 can be suppressed. Therefore, in the embodiment, even if an abnormality occurs in the battery cells 100 of some battery modules 10, it is possible to easily suppress abnormalities in the entire battery module 10.

[0039] In the embodiment, both ends of the hollow space HS in the Y direction are open. Therefore, gas that has entered the hollow space HS can be discharged from both ends of the hollow space HS in the Y direction. When the gas is discharged from both ends of the hollow space HS in the Y direction, the residence time of the gas in the hollow space HS can be made longer compared to when the gas is discharged through the connecting portion 516, and the gas can be more easily cooled in the hollow space HS. One of the ends of the hollow space HS in the Y direction may be closed, and the other end of the hollow space HS in the Y direction may be open. In other words, at least one of the ends of the hollow space HS in the Y direction may be open.

[0040] 2 and 3, the first plate 510 is the structure that defines the hollow space HS. However, a member other than the first plate 510 may be the structure that defines the hollow space HS. For example, the second plate 520 may have the same structure as the first plate 510 described with reference to FIGS. 2 and 3.

[0041] Although the embodiments of the present invention have been described above with reference to the drawings, these are merely examples of the present invention, and various other configurations can also be adopted. [Explanation of symbols]

[0042] 10 Battery module, 100 Battery cell, 110 Exterior material, 120 Terminal group, 122 Positive terminal, 124 Negative terminal, 200 Compression pad, 300 First voltage detection device, 310 First holder, 311 First opening, 320 First voltage detection terminal, 340 First connector, 400 Second voltage detection device, 410 Second holder, 411 Second opening, 420 Second voltage detection terminal, 500 Module housing, 510 First plate, 512 Plate main body, 513 Internal hole, 514 Protrusion, 516 Connection portion, 520 Second plate, 530 Third plate, 532 First insulating cover, 540 Fourth plate, 542 Second insulating cover, 550 Fifth plate, 552 Thermally conductive adhesive, 560 Sixth plate, 610 Positive bus bar, 620 Negative bus bar, ES external space, HS hollow space, IS internal space

Claims

1. A battery cell; a structure that defines a hollow space between one space in which the battery cell is located and another space located outside the battery cell, and a hole that connects the hollow space and the one space to each other; Equipped with The structure isolates the hollow space and the other space from each other.

2. The battery module of claim 1 , wherein the structure defines a plurality of the holes.

3. The battery module according to claim 1 , wherein the hollow space is open at least on one of both ends of the hollow space in a direction perpendicular to a direction connecting the one space and the other space.

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