Battery case

Abstract

To provide a technique capable of suppressing an injury risk of a battery against a load applied from an upper direction of a vehicle.SOLUTION: A load applied from an upper direction of a vehicle can be easily input to a load support member due to an existence of the load support member arranged at a position far from a battery cell from a pressing force member that presses the battery cell. Although the load support member receiving a load is deformed toward the battery cell, the load support member and the battery cell are not contacted because the load support member is separated from the battery cell. Thus, load transmission to a battery cell lamination body can be suppressed.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present disclosure relates to a battery case for housing a battery cell stack. [Background technology]

[0002] Patent Document 1 discloses technology relating to a vehicle mounting structure for a battery pack having multiple battery cells. The battery pack installed on the floor of the vehicle includes battery cells, a battery pack case in which the multiple battery cells are arranged side by side, and a cushioning member. The cushioning member is arranged so that it is sandwiched between the battery cells and the floor or between the battery cells and the battery pack case by fixing the battery pack case to the floor. This makes it possible to absorb the tolerance of the battery cells, so that the multiple battery cells can be reliably fixed with a simple configuration while ensuring high reliability. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-123227 Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-mentioned conventional technology, when a load is applied from above the vehicle, the load is easily transferred to the battery via the battery case and the cushioning member. The fact that the load is easily transferred to the battery, i.e., the battery is easily damaged, may shorten the battery's lifespan.

[0005] One object of the present disclosure is to provide a technology that reduces the risk of battery damage as described above, and thereby contributes to extending the life of on-board batteries. [Means for solving the problem]

[0006] The first aspect relates to a battery case for storing a battery cell stack in which a plurality of battery cells are stacked. The battery case is a pressing member that presses the battery cell stack; a load support member spaced apart from the battery cell stack; a connecting member that connects the pressing member and the load supporting member; Equipped with. The pressing member is disposed opposite the battery cell stack; The load bearing member is The pressing member is disposed so as to face the battery cell stack in the same direction as the pressing member, and is disposed at a position farther away from the battery cell stack than the pressing member.

[0007] The second aspect has the same features as the first aspect, as well as the following features. The load supporting member and the pressing member are an image of the load support member projected onto the battery cell stack; Image of the pressing member projected onto the battery cell stack are arranged so that they do not overlap each other.

[0008] The third aspect has the following features in addition to those of the first aspect. The connecting member is It has less rigidity than the load-bearing member.

[0009] The fourth aspect has the following features in addition to those of the first aspect. The connecting member is a first connection portion that is a portion of the load support member on a side that faces the battery cell stack; a second connecting portion that is a portion of the pressing member on a side facing the battery cell stack; are linked together.

[0010] A fifth aspect has the following features in addition to any one of the first to fourth aspects. A cushioning member disposed between the battery cell stack and the pressing member Equipped with. Effect of the Invention

[0011] According to the first aspect, because the load support member is disposed farther away than the pressing member, the load is easily input to the load support member. When the load support member receives the load, it deforms toward the battery cell stack, but because the load support member is spaced apart from the battery cell stack, the two do not come into contact with each other, and transmission of the load from the load support member to the battery cell stack is suppressed.

[0012] According to the second aspect, the load support member and the pressing member are arranged so that they do not "overlap" (details of the arrangement will be described later). This makes it difficult for the load support member and the pressing member to come into contact when the load support member receives a load and deforms toward the battery cell stack. This makes it possible to suppress the transmission of the load to the battery cell stack via the pressing member.

[0013] According to a third aspect, the connecting member has a lower rigidity than the load support member. As a result, the connecting member with low rigidity receives the load transmitted from the load support member, deforms, and absorbs the energy. As a result, the load is less likely to be transmitted to the pressing member, and transmission of the load to the battery cell stack via the pressing member can also be suppressed. Furthermore, if the connecting member can be implemented using a low-rigidity member, its cross-sectional area can be made smaller than other parts, and the amount of reinforcing material used can be reduced, leading to cost reduction and weight reduction.

[0014] According to a fourth aspect, the connecting member "connects" the load support member and the pressing member at their bottoms (details of the connection will be described later). This allows the load support member to have a larger margin for deformation. In other words, by connecting at their bottoms, the clearance between the load support member and the pressing member can be reduced by the thickness of the load support member compared to when the load support member and the pressing member are not connected at their bottoms, which results in a reduction in the thickness of the battery pack.

[0015] According to a fifth aspect, a buffer member is interposed between the pressing member and the battery cell stack, which not only increases the degree of fixation between the battery cell stack and the pressing member, but also ensures the space between the pressing member and the battery cell stack that is necessary for bottom connection. [Brief description of the drawings]

[0016] [Figure 1] 1 is a schematic diagram of a vehicle equipped with a battery pack according to an embodiment. [Diagram 2] 1 is a cross-sectional view showing a configuration of a battery pack according to an embodiment. [Diagram 3] FIG. 2 is a perspective view showing a configuration of a battery case according to the embodiment. [Figure 4] FIG. 4 is a cross-sectional view of the battery pack for explaining the operation and effect. [Diagram 5] FIG. 13 is a schematic diagram for explaining the action and effect. [Figure 6] FIG. 13 is a plan view showing a modified example of the battery case according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Embodiments of the present disclosure will be described with reference to the accompanying drawings.

[0018] 1. Main components of the battery case 1 is a schematic diagram of a vehicle 1 equipped with a battery pack 10 according to an embodiment. In general, the battery pack 10 is mounted under the floor of the vehicle 1. The battery pack 10 is used as a power source for electric vehicles such as a BEV, a PEV, or a HEV.

[0019] 1, the FR direction indicated by the arrow indicates the direction in which the vehicle 1 moves forward, the UP direction indicates the upward direction of the vehicle 1, and the LH direction indicates the left direction as seen by a passenger in the vehicle 1, that is, the direction toward the front of the paper. The same applies to the arrows shown in Fig. 2 and subsequent figures.

[0020] 2 is a cross-sectional view showing the configuration of a battery pack 10 according to an embodiment. Here, the configuration of the battery pack 10 will be described mainly based on (A) in FIG.

[0021] The battery pack 10 includes a battery cell stack 20 configured by stacking a plurality of battery cells, and a battery case 30 in which the battery cell stack 20 is housed. The battery cells are rechargeable secondary batteries, such as lithium ion secondary batteries. The battery cell stack 20 is illustrated with its stacking direction along the LH direction and has a substantially rectangular parallelepiped shape. The battery case 30 includes an outer shell 31, a load supporting member 32, a pressing member 33, and a connecting member 34, as described below.

[0022] The outer shell portion 31 is configured to cover the battery cell stack 20. The outer shell portion 31 is not configured to completely encase the battery cell stack 20, but rather has a shape that is partially open as shown in Figure 2.

[0023] The load support member 32 is a member that extends in a cantilever shape from the end of the outer shell portion 31. The load support member 32 is spaced apart from the battery cell stack 20.

[0024] The pressing member 33 is a member for fixing the battery cell stack 20 to the outer shell portion 31 so that the battery cell stack 20 does not move due to vibrations during running, etc. For example, the pressing member 33 is disposed above the battery cell stack 20, and presses the battery cell stack 20 toward the bottom of the outer shell portion 31.

[0025] 2, a buffer member 40 may be interposed between the pressing member 33 and the battery cell stack 20. The buffer member 40 may be provided on the side opposite to the side where the pressing member 33 is installed, that is, between the outer shell portion 31 and the battery cell stack 20. The buffer member 40 is preferably made of an elastic material such as rubber or sponge, and increases the degree of fixation between the battery cell stack 20 and the battery case 30.

[0026] Typically, the outer shell 31, the load supporting member 32 and the pressing member 33 are constructed of metal panels made of an alloy or the like.

[0027] Here, we will explain the positional relationship between the load support member 32 and the pressing member 33. First, the load support member 32 and the pressing member 33 are positioned so as to face each other in the same direction as the battery cell stack 20. Second, the load support member 32 is positioned farther away from the battery cell stack 20 than the pressing member 33 is.

[0028] Furthermore, it is preferable that the load support members 32 and the pressing members 33 are arranged so that their images do not overlap when projected onto the battery cell stack 20 (the reasons for this will be described later). Hereinafter, this type of arrangement will be referred to as a "non-overlapping arrangement."

[0029] The connecting member 34 connects the load supporting member 32 and the pressing member 33. It is desirable that the connecting member 34 has a lower rigidity than the load supporting member 32.

[0030] Furthermore, a desirable mode is one in which the connecting member 34 connects the first connecting portion 32a of the load support member 32 and the second connecting portion 33a of the pressing member 33. Here, the first connecting portion 32a is a part of the side of the load support member 32 that faces the battery cell stack 20. Moreover, the second connecting portion 33a is a part of the surface of the pressing member 33 that faces the battery cell stack 20. (Hereinafter, this type of connection mode will be referred to as "underside connection.") One example of underside connection is one in which a thin sheet metal patch is used as the connecting member 34, and the first connecting portion 32a and the second connecting portion 33a are connected by welding.

[0031] The material constituting the connecting member 34 is not limited to the thin metal patch exemplified above, but may be a resin material, a leather or cloth material, a sponge, etc. As yet another example, the connecting member 34 may be shaped so as to be bent in the direction toward the battery cell stack 20, as shown in (B) in Fig. 2.

[0032] Here, to achieve bottom connection, a space is necessary between the second connecting portion 33a and the battery cell stack 20. In order to secure that space, a buffer member 40 that is smaller than the pressing member 33 may be used, as shown in Fig. 2. Alternatively, instead of using the buffer member 40, the cross-sectional shape of the pressing member 33 may be made stepped to secure the space.

[0033] 3 is a perspective view showing the configuration of a battery case 30 according to an embodiment. To summarize the above, the battery case 30 includes an outer shell portion 31, a load support member 32, a pressing member 33, and a connecting member 34 that connects the load support member 32 and the pressing member 33. The battery cell stack 20 is housed inside, thereby isolating the battery cell stack 20 from the outside.

[0034] 2. Issues and their effects In the prior art (for example, Patent Document 1), there is no member equivalent to the load support member 32 in the present disclosure, and the load from the UP direction is easily transmitted to the battery cell via the battery case and the buffer member. The fact that the load is easily transmitted to the battery, i.e., the battery is easily damaged, may shorten the battery life.

[0035] 4 is a cross-sectional view of the battery pack 10 for explaining the action and effect of the present disclosure. The present disclosure solves the above-mentioned problems by the following action. In the present disclosure, the load support member 32 is disposed at a position farther from the battery cell stack 20 than the pressing member 33 is, so that the load is easily input to the load support member. When the load support member 32 receives the load, it deforms toward the battery cell stack 20, but since the load support member 32 is separated from the battery cell stack 20, the two do not come into contact with each other, and the transmission of the load from the load support member 32 to the battery cell stack 20 is suppressed.

[0036] Here, if the load support member 32 and the pressing member 33 are arranged so that they do not overlap, when the load support member 32 receives a load and deforms toward the battery cell stack 20, the load support member 32 and the pressing member 33 are less likely to come into contact with each other. This therefore makes it possible to suppress the transmission of the load to the battery cell stack 20 via the pressing member 33, and therefore it is more preferable that the load support member 32 and the pressing member 33 do not overlap.

[0037] Here, if the connecting member 34 has a lower rigidity than the load support member 32, the low-rigidity connecting member 34 will receive the load transmitted from the load support member 32 and deform, absorbing the energy. As a result, the load will be less likely to be transmitted to the pressing member 33, and transmission of the load to the battery cell stack 20 via the pressing member 33 can also be suppressed. Therefore, it is more preferable for the connecting member 34 to have a low rigidity. Furthermore, if the connecting member 34 can be made of a low-rigidity material, the cross-sectional area of ​​the connecting member 34 can be made smaller than other parts and the amount of reinforcing material used can be reduced, leading to cost and weight reduction.

[0038] The effect of connecting member 34 connecting load support member 32 and pressing member 33 by underside connection will be described with reference to Fig. 5. Here, the distance in the UP direction between load support member 32 and pressing member 33 is taken as Δ, and the thickness of load support member 32 is taken as t. In addition, for load support member 32 and connecting member 34 in the figure, the parts drawn with dashed lines show the state before receiving a load (before deformation), and the parts drawn with solid lines show the state after deformation due to the load.

[0039] 5(A), consider the case where the connecting member 34 is not connected at its bottom. In this case, when a load acts on the load support member 32 and it deforms in the direction of the battery cell stack 20, at the point where it has deformed by Δ, the connecting member 34 comes into contact with and is sandwiched between the load support member 32 and the pressing member 33, generating resistance. The generation of resistance means that the load is transmitted to the pressing member 33, and as a result, it means that the load is easily transmitted to the battery cell stack 20.

[0040] On the other hand, consider the case where the bottom surfaces are connected through (B) in FIG. 5. Even when the load support member 32 is deformed by Δ, the connecting member 34 is not sandwiched between the load support member 32 and the pressing member 33, and no resistance is generated as a result. In this case, the deformation continues, and when the deformation amount reaches Δ+t, the upper end of the load support member 32 and the upper end of the pressing member 33 are aligned. At this time, if the load acts on a wide area, the load begins to act directly on the pressing member 33, and so the load can act on the pressing member 33 at the deformation amount Δ+t. In other words, the deformation amount Δ+t can be said to be the maximum deformation possible on the premise that the load is not transmitted to the pressing member 33.

[0041] That is, when the bottom connections are made, the deformation amount can be up to Δ+t, which is the maximum possible value, whereas when the bottom connections are not made, the deformation amount can only be up to Δ. This means that when the bottom connections are made, the deformation amount can be made larger by the thickness t of the load support member 32 than when the bottom connections are not made. In other words, when the same allowable deformation amount is to be realized, by making the bottom connections, the distance Δ can be reduced by the thickness t of the load support member 32, which leads to a reduction in the thickness of the battery pack 10.

[0042] When the cushioning member 40 is interposed between the pressing member 33 and the battery cell stack 20, not only is the degree of fixation between the battery cell stack 20 and the battery case 30 increased, but the space required for underside connection between the second connecting portion 33a and the battery cell stack 20 can be secured.

[0043] Due to the above-mentioned action, the present disclosure reduces the risk of damage to the battery cell stack 20, thereby contributing to a longer life for on-board batteries.

[0044] 3. Variations 3 shows an example in which one pressing member 33 is disposed in the center of the battery case 30, and the connecting members 34 and the load supporting members 32 are disposed so as to surround the pressing member 33, but other configurations are possible as long as the effects of the present disclosure can be achieved. Below, several modified examples that can achieve the effects of the present disclosure are shown.

[0045] 3-1. First modified example 6A is a plan view of a first modified example of the battery case 30 according to the embodiment, viewed from the UP direction. In the example shown in FIG. 5, the load support member 32 is separated into two parts, and a connecting member 34 and a load support member 32 are disposed around each part. In other words, the load support member 32 is shaped like a square, and the load support member 32 and the connecting member 34 are disposed in shapes corresponding to the two openings. In this way, the pressing member 33 may be separated into a plurality of parts, and the effect of the present disclosure is still achieved in this case.

[0046] 3-2. Second variant 6B is a plan view of a second modified example of the battery case 30 according to the embodiment, viewed from the UP direction. In the example shown in FIG. 6, the load support member 32 is not completely surrounded by the connecting member 34 and the load support member 32, and its end extends to the end of the battery case 30. From another perspective, the load support member 32 is separated into two parts, and the load support member 32 and the connecting member 34 are arranged in a shape corresponding to the empty part. In this way, the load support member 32 may be separated into multiple parts, and the effect of the present disclosure is still achieved in this case. [Explanation of symbols]

[0047] 1: Vehicle 10: Battery pack 20: Battery cell stack 30: Battery case 31: Outer shell 32: Load-bearing member 32a: First connection part 33 Pressing member 33a: Second connection part 34: Connecting member 40: Cushioning material

Claims

1. A battery case for storing a battery cell stack in which a plurality of battery cells are stacked, a pressing member that presses the battery cell stack; a load support member spaced apart from the battery cell stack; a connecting member that connects the pressing member and the load supporting member; Equipped with The pressing member is a battery cell stack; The load support member is The pressing member is disposed so as to face the battery cell stack in the same direction as the pressing member, and is disposed at a position farther away from the battery cell stack than the pressing member. Battery case.

2. The battery case according to claim 1 , The load support member and the pressing member are an image of the load support member projected onto the battery cell stack; and An image of the pressing member projected onto the battery cell stack; are arranged so that they do not overlap each other. Battery case.

3. The battery case according to claim 1 , The connecting member is Less rigid than the load-bearing member Battery case.

4. The battery case according to claim 1 , The connecting member is a first connection portion that is a portion of the load support member on a side that faces the battery cell stack; a second connecting portion that is a part of the pressing member on a side facing the battery cell stack; are connected. Battery case.

5. The battery case according to any one of claims 1 to 4, A buffer member disposed between the battery cell stack and the pressing member. Further equipped Battery case.

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