JP2023104210A - battery pack - Google Patents

Abstract

To provide a battery pack which can prevent removal of a battery stack from a case member while ensuring the battery stack to be easily housed into the case member.SOLUTION: In a battery pack 1, a battery stack 11 is housed inside a battery case 12 in such a manner that an outer surface 71 of an end plate 22 comes into contact with a wall part 52 of the battery case 12. On a cross section in a lamination direction of battery cells 31 in the battery pack 1, a battery laminate 21 is bent so as to protrude downward, and the wall part 52 of the battery case 12 is formed so as to extend in parallel to the vertical direction.SELECTED DRAWING: Figure 2

Description

The present disclosure relates to battery packs.

As a prior art related to a battery pack, Patent Document 1 discloses that the wall portion (side wall) of the battery case is made into an under shape that expands outward as it goes downward, thereby suppressing the separation of the battery stack from the battery case. A battery pack is disclosed that

JP 2020-95895 A

As shown in FIG. 7, in the battery pack disclosed in Patent Document 1, the wall portion 152 of the battery case 112 is under-shaped. Therefore, when the battery stack 111 is housed in the battery case 112, the compression amount δ0 of the battery stack 111 needs to be increased. Therefore, when the battery stack 111 is difficult to compress (the spring constant of the battery stack 111 is high), the battery stack 111 may not be accommodated in the battery case 112 .

Accordingly, the present disclosure has been made to solve the above-described problems, and is a battery pack capable of suppressing the separation of the battery stack from the case member while ensuring ease of housing the battery stack in the case member. intended to provide

One aspect of the present disclosure, which has been made to solve the above problems, is a battery pack including a battery stack and a box-shaped case member that houses the battery stack, wherein the battery stack includes a plurality of stacked batteries. a battery stack composed of cells and spacers disposed between adjacent battery cells; and a pair of end plates disposed in contact with both ends of the battery cells in the stacking direction of the battery stack. , wherein the case member includes a bottom portion located below the battery stack and a wall portion extending upward from an outer peripheral edge of the bottom portion, and the battery stack in the end plate and the The battery stack is housed in the case member so that the opposite surface is in contact with the wall portion of the case member, and the cross section in the stacking direction of the battery cells in the battery pack , wherein the battery stack is convexly curved downward, and the wall portion of the case member is formed so as to extend in parallel in the vertical direction.

According to this aspect, since the battery stack is curved downward, it is difficult for the battery stack to move up and down when the battery pack receives vibration or impact. Therefore, it is possible to suppress vertical displacement of the battery stack including the battery stack. Therefore, it is possible to suppress the separation of the battery stack from the case member.

Further, the wall portion of the case member is formed so as to extend in parallel in the vertical direction, that is, it is not formed in an under-shape as in Patent Document 1. Therefore, when the battery stack is compressed and accommodated in the case member, the amount of compression of the battery stack can be reduced. Therefore, even if the battery stack is difficult to compress (the spring constant of the battery stack is high), the battery stack can be accommodated in the case member. Therefore, it is possible to ensure the ease of housing the battery stack in the case member.

In the above aspect, the battery cell is formed in a rectangular or substantially rectangular shape, and the end plate has a surface in contact with the battery stack that extends from the bottom to the top of the case member. The end plate is formed so as to be inclined inward, and a surface of the end plate in contact with the wall portion of the case member is formed parallel to the vertical direction, and the spacer is arranged in the stacking direction of the battery cells in the spacer. is formed such that the thickness of the spacer gradually decreases from the lower end of the spacer toward the upper end of the spacer.

According to this aspect, the spacer whose thickness gradually decreases from the lower end to the upper end, and the end plate whose surface in contact with the battery stack is inclined inwardly of the case member from the lower side to the upper side. By using , the battery stack can be easily curved downward.

In the above aspect, the battery cell is formed in a rectangular or substantially rectangular shape, and the end plate has a surface in contact with the battery stack and a surface in contact with the wall of the case member that extends vertically. A first spacer and a second spacer are used as the spacers, and the first spacer is the battery cell in the first spacer. The thickness of the cell in the stacking direction is formed so as to gradually increase from the lower end portion of the first spacer toward the upper end portion of the first spacer, and the second spacer is formed so that the thickness of the cell in the second spacer increases. The thickness of the cells in the stacking direction is formed such that it gradually decreases from the lower end portion of the second spacer toward the upper end portion of the second spacer, and a plurality of cells are arranged along the stacking direction of the battery cells. In the above spacer, preferably, the first spacers are arranged at least at both ends in the arrangement direction of the spacers, and the second spacers are arranged inside the case member with respect to the first spacers.

According to this aspect, while the shape of the end plate is a simple shape such as a rectangle or a substantially rectangle, two types of spacers (that is, the first spacer and the second spacer) are used to easily lower the battery stack. can be curved convexly.

Another aspect of the present disclosure, which has been made to solve the above problems, is a battery pack including a battery stack and a box-shaped case member for housing the battery stack, wherein the battery stack includes a plurality of stacked battery packs. A battery stack composed of battery cells and spacers disposed between adjacent battery cells; and a pair of end plates disposed in contact with both ends of the battery cells in the stacking direction of the battery stack. and the case member includes a bottom located below the battery stack and a wall extending upward from the outer peripheral edge of the bottom, and the battery stack in the end plate The battery stack is housed in the case member so that the surface opposite to is in contact with the wall portion of the case member, and the cross section in the stacking direction of the battery cells in the battery pack has the battery stack is convexly curved downward, and the wall portion of the case member is formed so as to incline outward from the case member as it goes from the lower side to the upper side; characterized by

According to this aspect, since the battery stack is curved downward, it is difficult for the battery stack to move up and down when the battery pack receives vibration or impact. Therefore, it is possible to suppress vertical displacement of the battery stack including the battery stack. Therefore, it is possible to suppress the separation of the battery stack from the case member.

In addition, the wall portion of the case member is formed so as to incline outward from the case member as it goes from the lower side to the upper side, that is, it is not formed in an under-shape as in Patent Document 1. Therefore, when the battery stack is compressed and accommodated in the case member, the amount of compression of the battery stack can be reduced. Therefore, even if the battery stack is difficult to compress, the battery stack can be accommodated in the case member. Therefore, it is possible to ensure the ease of housing the battery stack in the case member.

In addition, since the wall of the case member is formed so as to incline outward from the case member as it goes from the lower side to the upper side, a draft angle is ensured during molding of the case member, which reduces production of the case member. can improve sexuality.

In the above aspect, the battery cell is formed in a rectangular or substantially rectangular shape, and the end plate has a surface in contact with the battery stack that extends from the bottom to the top of the case member. The surface of the end plate in contact with the wall portion of the case member is formed so as to be inclined inwardly, and the surface of the end plate in contact with the wall portion of the case member is formed so as to be inclined outwardly of the case member from the lower side to the upper side. Preferably, the spacer is formed so that the thickness of the spacer in the stacking direction of the battery cells gradually decreases from the lower end of the spacer toward the upper end of the spacer.

According to this aspect, the spacer whose thickness gradually decreases from the lower end to the upper end, and the end plate whose surface in contact with the battery stack is inclined inwardly of the case member from the lower side to the upper side. By using , the battery stack can be easily curved downward.

In the above aspect, the battery cell is formed in a rectangular or substantially rectangular shape, the end plate has a surface in contact with the battery stack that is parallel to the vertical direction, and the end plate a surface of the case member in contact with the wall portion is formed so as to incline outward from the case member from the lower side toward the upper side, and the spacers include a first spacer and a second spacer. In the first spacer, the thickness of the first spacer in the stacking direction of the battery cells gradually increases from the lower end of the first spacer toward the upper end of the first spacer. In the second spacer, the thickness of the second spacer in the stacking direction of the battery cells gradually decreases from the lower end of the second spacer toward the upper end of the second spacer. and arranged along the stacking direction of the battery cells, the first spacers are arranged on at least both ends of the spacers in the arrangement direction, and the case member is attached to the first spacers. It is preferable that the second spacer is arranged inside the .

According to this aspect, two types of spacers (that is, the first spacer and the second spacer) are used while forming the surface of the end plate in contact with the wall of the case member in accordance with the inclination of the wall of the case member. , the battery stack can be easily curved downward.

In the above aspect, it is preferable that the battery stack is accommodated in the case member while being compressed in the stacking direction of the battery cells.

According to this aspect, the separation of the battery stack from the case member can be suppressed more reliably.

In the above aspect, it is preferable that the upper surface of the bottom portion of the case member is convexly curved downward.

According to this aspect, it is possible to stably maintain the state in which the battery stack is curved downward.

According to the battery pack of the present disclosure, it is possible to prevent the battery stack from being detached from the case member while ensuring ease of housing the battery stack in the case member.

1 is an overall perspective view (schematic diagram) of a battery pack according to an embodiment; FIG. FIG. 2 is a cross-sectional view taken along line AA of FIG. 1 in the first embodiment; FIG. 4 is a diagram showing how the battery stack is accommodated in the battery case in the first embodiment; FIG. 2 is a cross-sectional view taken along line AA of FIG. 1 in the second embodiment; FIG. 2 is a cross-sectional view taken along the line AA of FIG. 1 in the third embodiment; FIG. 11 is a cross-sectional view taken along the line AA of FIG. 1 in the fourth embodiment; FIG. 2 is a diagram showing how a battery stack is housed in a battery case in Patent Document 1;

Embodiments of the battery pack of the present disclosure will be described below.

<About the overall outline of the battery pack>
First, an overall outline of the battery pack 1 of the present embodiment will be described.

As shown in FIG. 1 , the battery pack 1 of this embodiment has a battery stack 11 and a box-shaped battery case 12 that houses the battery stack 11 . Note that the battery case 12 is an example of the “case member” of the present disclosure.

The battery stack 11 includes a battery stack 21 and a pair of end plates 22 .

The battery stack 21 is composed of a plurality of rectangular battery cells 31 stacked and arranged in the X direction shown in FIG. 1 and spacers 32 arranged between adjacent battery cells 31 . In addition, in this embodiment, the two battery stacks 11 are arranged side by side in the Y direction shown in FIG.

The battery cell 31 has two electrode terminals 42 on its upper surface 41 . One of the two electrode terminals 42 is a positive terminal and the other is a negative terminal.

The pair of end plates 22 are arranged so as to be in contact with both ends in the stacking direction of the battery cells 31 in the battery stack 21 .

The battery case 12 is a box-shaped member with an open top, and includes a bottom portion 51 and wall portions 52 .

The bottom portion 51 is positioned below the battery stack 11 (downward in the Z direction). Moreover, the wall portions 52 are positioned on both sides of the battery stack 11 (both sides in the X direction and the Y direction). Wall portion 52 is formed to extend upward in the height direction (Z direction) of battery pack 1 from outer peripheral edge portion 61 (see FIG. 2 and the like) of bottom portion 51 .

Such a battery case 12 has two storage spaces for the battery stacks 11 that are surrounded by the bottom portion 51 and the wall portion 52 . A battery stack 11 is stored in each of these two storage spaces.

<Embodiments of battery stack and battery case>
Next, examples of the battery stack 11 and the battery case 12 will be described.

(First embodiment)
First, the first embodiment will be described.

As shown in FIG. 2 , the battery stack 11 is arranged such that the outer surface 71 (that is, the surface opposite to the battery stack 21 ) of the end plate 22 is in contact with the wall portion 52 of the battery case 12 . It is housed within 12. The battery stack 11 is accommodated in the battery case 12 while being compressed in the stacking direction of the battery cells 31 .

In the present embodiment, in the cross section shown in FIG. 2, that is, in the cross section in the stacking direction of the battery cells 31 in the battery pack 1 (sectional view along line AA in FIG. 1), the battery stack 21 is positioned on the lower side. curved convexly. The upper surface 81 of the bottom portion 51 of the battery case 12 is also curved downward.

Further, the wall portion 52 of the battery case 12 is formed to extend parallel to the vertical direction (Z direction).

In addition, the inner surface 72 (that is, the surface in contact with the battery stack 21) of the end plate 22 is formed so as to incline toward the inside of the battery case 12 from the lower side toward the upper side. On the other hand, the outer side surface 71 of the end plate 22 is formed parallel to the vertical direction. In addition, the battery cell 31 is formed in a rectangular or substantially rectangular shape.

The spacer 32 is formed such that the thickness T of the spacer 32 in the stacking direction of the battery cells 31 gradually decreases from the lower end portion 91 toward the upper end portion 92 . The lower end surface 73 of the end plate 22 and the lower end portion 91 of the spacer 32 are in contact with the upper surface 81 of the bottom portion 51 of the battery case 12 .

As described above, in the present embodiment, the battery stack 21 is curved downward, so that the battery stack 21 is less likely to move up and down when the battery pack 1 is subjected to vibration or impact. Therefore, vertical displacement of the battery stack 11 including the battery stack 21 can be suppressed. Therefore, it is possible to prevent the battery stack 11 from detaching from the battery case 12 .

Moreover, the wall portion 52 of the battery case 12 is formed so as to extend in parallel in the vertical direction, that is, it is not formed in an under shape as in Patent Document 1. Therefore, as shown in FIG. 3, when the battery stack 11 is compressed (pressurized) and housed in the battery case 12, the amount of compression .delta.1 (<.delta.0) of the battery stack 11 can be reduced. Therefore, even if the battery stack 11 is difficult to compress (the spring constant of the battery stack 11 is high), the battery stack 11 can be accommodated in the battery case 12 . Therefore, it is possible to ensure ease of housing the battery stack 11 in the battery case 12 .

Moreover, the wall portion 52 of the battery case 12 may be formed so as to extend in parallel in the vertical direction, and does not have to be formed into a complicated under-shape as in Patent Document 1. Therefore, the battery case 12 can be manufactured at low cost.

Also, the spacer 32 whose thickness T gradually decreases from the lower end portion 91 to the upper end portion 92, and the end plate 22 whose inner side surface 72 inclines toward the inside of the battery case 12 as it goes from the lower side to the upper side. , the battery stack 21 can be easily curved downward.

(Second embodiment)
Next, the second embodiment will be described, mainly focusing on the differences from the first embodiment.

In this embodiment, in the cross section shown in FIG. 4, that is, in the cross section in the stacking direction of the battery cells 31 in the battery pack 1 (sectional view along line AA in FIG. 1), the battery stacking is performed in the same manner as in the first embodiment. The body 21 is convexly curved downward.

On the other hand, unlike the first embodiment, the end plate 22 is formed in a rectangular or substantially rectangular shape such that the inner side surface 72 and the outer side surface 71 of the end plate 22 are formed parallel to each other in the vertical direction. there is

As the spacers 32, first spacers 32A and second spacers 32B are used. Specifically, the first spacer 32A is formed such that the thickness T in the stacking direction of the battery cells 31 in the first spacer 32A gradually increases from the lower end portion 91 toward the upper end portion 92. . Further, the second spacer 32B is formed so that the thickness T in the stacking direction of the battery cells 31 in the second spacer 32B gradually decreases from the lower end portion 91 toward the upper end portion 92 .

Then, for the plurality of spacers 32 arranged along the stacking direction of the battery cells 31 in this manner, the first spacers 32A are arranged at least at both ends of the spacers 32 in the arrangement direction, and the battery case is arranged relative to the first spacers 32A. 12, a second spacer 32B is arranged. In the example shown in FIG. 4, specifically, a total of four first spacers 32A are arranged at both end portions in the arrangement direction of the spacers 32 and a portion one inside (inside the battery case 12). there is In addition, a total of four second spacers 32B are arranged inside the battery case 12 relative to the first spacers 32A.

As described above, in this embodiment, while the end plate 22 has a simple shape such as a rectangle or a substantially rectangular shape, two types of spacers 32 (that is, the first spacer 32A and the second spacer 32B) are used to easily The battery stack 21 can be curved convexly downward.

(Third embodiment)
Next, a description will be given of the third embodiment, and mainly the differences from the first and second embodiments will be described.

In this embodiment, in the cross section shown in FIG. 5, that is, in the cross section in the stacking direction of the battery cells 31 in the battery pack 1 (sectional view along line AA in FIG. 1), as in the first and second embodiments, The battery stack 21 is convexly curved downward.

On the other hand, unlike the first and second embodiments, the wall portion 52 of the battery case 12 is formed so as to incline outward from the battery case 12 from the lower side toward the upper side. Here, the inclination angle θ of the wall portion 52 is, for example, greater than 0° and within 10°. As shown in FIG. 5, the inclination angle .theta. is the angle at which the wall portion 52 inclines toward the outside of the battery case 12 with respect to the vertical direction, and serves as a draft angle when the battery case 12 is molded.

In addition, the outer side surface 71 of the end plate 22 is formed so as to be inclined outward from the battery case 12 from the lower side to the upper side so as to correspond to the inclined wall portion 52 of the battery case 12 . It is

The inner side surface 72 of the end plate 22 is formed so as to incline toward the inside of the battery case 12 from the lower side toward the upper side. Moreover, the spacer 32 is formed such that the thickness T of the spacer 32 in the stacking direction of the battery cells 31 gradually decreases from the lower end portion 91 toward the upper end portion 92 .

As described above, in the present embodiment, the battery stack 21 is curved downward, so that the battery stack 21 is less likely to move up and down when the battery pack 1 is subjected to vibration or impact. Therefore, vertical displacement of the battery stack 11 including the battery stack 21 can be suppressed. Therefore, it is possible to prevent the battery stack 11 from detaching from the battery case 12 .

In addition, the wall portion 52 of the battery case 12 is formed so as to incline outward from the battery case 12 from the lower side to the upper side, that is, it is not formed in an under shape as in Patent Document 1. do not have. Therefore, when the battery stack 11 is compressed and accommodated in the battery case 12, the amount of compression of the battery stack 11 can be reduced. Therefore, even if the battery stack 11 is difficult to compress, the battery stack 11 can be accommodated in the battery case 12 . Therefore, it is possible to ensure ease of housing the battery stack 11 in the battery case 12 .

In addition, the wall portion 52 of the battery case 12 is formed so as to incline toward the outside of the battery case 12 as it goes from the lower side to the upper side. Productivity of the battery case 12 can be improved.

Also, the spacer 32 whose thickness T gradually decreases from the lower end portion 91 to the upper end portion 92, and the end plate 22 whose inner side surface 72 inclines toward the inside of the battery case 12 as it goes from the lower side to the upper side. , the battery stack 21 can be easily curved downward.

(Fourth embodiment)
Next, a description will be given of the fourth embodiment, and mainly the differences from the first, second and third embodiments will be described.

In the present embodiment, as shown in FIG. 6 , the outer surface 71 of the end plate 22 is inclined toward the upper side of the battery case 12 so as to correspond to the inclined wall portion 52 of the battery case 12 . It is formed so as to incline outward. In addition, the inner side surface 72 of the end plate 22 is formed parallel to the vertical direction. Further, as spacers 32, first spacers 32A and second spacers 32B are used.

As described above, in this embodiment, while the outer surface 71 of the end plate 22 is formed to match the inclination of the wall portion 52 of the battery case 12, two types of spacers 32 (that is, the first spacer 32A and the second spacer 32B) are formed. can be used to easily bend the battery stack 21 convexly downward.

It should be noted that the above-described embodiment is merely an example, and does not limit the present disclosure in any way, and it goes without saying that various improvements and modifications are possible without departing from the scope of the present disclosure.

For example, the lower surface 82 (see FIG. 2, etc.) of the bottom portion 51 of the battery case 12 may be curved downwards, or may not be curved downwards from the viewpoint of manufacturing. good (eg it can be a flat surface). Further, the lower end portion 91 of the spacer 32 and the upper surface 81 of the bottom portion 51 of the battery case 12 do not have to be in contact with each other.

1 Battery pack 11 Battery stack 12 Battery case 21 Battery stack 22 End plate 31 Battery cell 32 Spacer 32A First spacer 32B Second spacer 51 Bottom 52 Wall 61 Peripheral edge 71 Outer surface 72 Inner surface 81 Upper surface 91 Lower end 92 Upper end T Thickness δ0, δ1 Compression amount θ Tilt angle

Claims (8)

a battery stack;
a box-shaped case member that houses the battery stack;
In a battery pack having
The battery stack is
a battery stack composed of a plurality of stacked battery cells and spacers disposed between the adjacent battery cells;
a pair of end plates arranged in contact with both ends in the stacking direction of the battery cells in the battery stack;
with
The case member is
a bottom positioned below the battery stack;
a wall extending upward from the outer peripheral edge of the bottom;
with
The battery stack is accommodated in the case member such that the surface of the end plate opposite to the battery stack is in contact with the wall portion of the case member,
In a cross section in the stacking direction of the battery cells in the battery pack,
The battery stack is convexly curved downward,
the wall portion of the case member is formed to extend in parallel with the vertical direction;
A battery pack characterized by: The battery pack of claim 1,
the battery cell is formed in a rectangular or substantially rectangular shape,
The end plate is
a surface of the end plate in contact with the battery stack is formed so as to incline toward the inside of the case member from the bottom to the top;
and,
a surface of the end plate contacting the wall portion of the case member is formed parallel to the vertical direction,
the spacer is formed such that the thickness of the spacer in the stacking direction of the battery cells gradually decreases from the lower end of the spacer toward the upper end of the spacer;
A battery pack characterized by: The battery pack of claim 1,
the battery cell is formed in a rectangular or substantially rectangular shape,
The end plate is
The end plate is formed in a rectangular or substantially rectangular shape such that the surface of the end plate in contact with the battery stack and the surface of the case member in contact with the wall are formed in parallel in the vertical direction,
A first spacer and a second spacer are used as the spacers,
The first spacer is formed so that the thickness of the first spacer in the stacking direction of the battery cells gradually increases from the lower end of the first spacer toward the upper end of the first spacer,
The second spacer is formed so that the thickness of the second spacer in the stacking direction of the battery cells gradually decreases from the lower end of the second spacer toward the upper end of the second spacer,
Regarding the plurality of spacers arranged along the stacking direction of the battery cells,
The first spacers are arranged on at least both ends in the arrangement direction of the spacers,
the second spacer is arranged inside the case member with respect to the first spacer;
A battery pack characterized by: a battery stack;
a box-shaped case member that houses the battery stack;
In a battery pack having
The battery stack is
a battery stack composed of a plurality of stacked battery cells and spacers disposed between the adjacent battery cells;
a pair of end plates arranged in contact with both ends in the stacking direction of the battery cells in the battery stack;
with
The case member is
a bottom positioned below the battery stack;
a wall extending upward from the outer peripheral edge of the bottom;
with
The battery stack is accommodated in the case member such that the surface of the end plate opposite to the battery stack is in contact with the wall portion of the case member,
In a cross section in the stacking direction of the battery cells in the battery pack,
The battery stack is convexly curved downward,
the wall portion of the case member is formed so as to incline outward from the case member from the lower side toward the upper side;
A battery pack characterized by: In the battery pack of claim 4,
the battery cell is formed in a rectangular or substantially rectangular shape,
The end plate is
a surface of the end plate in contact with the battery stack is formed so as to incline toward the inside of the case member from the bottom to the top;
and,
a surface of the end plate in contact with the wall portion of the case member is formed so as to incline outward from the case member as it goes from the lower side to the upper side,
the spacer is formed such that the thickness of the spacer in the stacking direction of the battery cells gradually decreases from the lower end of the spacer toward the upper end of the spacer;
A battery pack characterized by: In the battery pack of claim 4,
the battery cell is formed in a rectangular or substantially rectangular shape,
The end plate is
a surface of the end plate in contact with the battery stack is formed parallel to the vertical direction,
and,
a surface of the end plate in contact with the wall portion of the case member is formed so as to incline outward from the case member as it goes from the lower side to the upper side,
A first spacer and a second spacer are used as the spacers,
The first spacer is formed so that the thickness of the first spacer in the stacking direction of the battery cells gradually increases from the lower end of the first spacer toward the upper end of the first spacer,
The second spacer is formed so that the thickness of the second spacer in the stacking direction of the battery cells gradually decreases from the lower end of the second spacer toward the upper end of the second spacer,
Regarding the plurality of spacers arranged along the stacking direction of the battery cells,
The first spacers are arranged on at least both ends in the arrangement direction of the spacers,
the second spacer is arranged inside the case member with respect to the first spacer;
A battery pack characterized by: In the battery pack according to any one of claims 1 to 6,
The battery stack is accommodated in the case member in a state of being compressed in the stacking direction of the battery cells;
A battery pack characterized by: The battery pack according to any one of claims 1 to 7,
the upper surface of the bottom portion of the case member is convexly curved downward;
A battery pack characterized by:

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