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 storing a battery cell laminate.

Background Art

[0002] Patent Document 1 discloses a technology related to an in-vehicle structure of a battery pack having a plurality of battery cells. The battery pack installed on the vehicle floor includes a battery cell, a battery pack case in which a plurality of battery cells are arranged side by side, and a buffer member. The buffer member is arranged so as to be sandwiched between the battery cell and the floor or between the battery cell and the battery pack case when the battery pack case is fixed to the floor. Thereby, since the tolerance of the battery cell can be absorbed, it is said that a plurality of battery cells can be securely fixed with a simple configuration while ensuring high reliability.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the above prior art, when a load is applied from above the vehicle, the load is easily transmitted to the battery through the battery case or the buffer member. The fact that the load is easily transmitted to the battery, that is, the battery is easily damaged, may shorten the life of the battery.

[0005] One object of the present disclosure is to provide a technology that suppresses the risk of damage to the battery as described above and thus contributes to extending the life of the in-vehicle battery.

Means for Solving the Problems

[0006] The first aspect relates to a battery case for housing a stack of battery cells, which consists of multiple battery cells stacked together. The battery case is A pressing member that presses the battery cell stack, A load-bearing member that is spaced apart from the battery cell stack, A connecting member that connects the pressing member and the load-supporting member. It is equipped with. The pressing member is It is positioned opposite the battery cell stack, The load-bearing member is, The battery cell stack is positioned so as to face the pressing member in the same direction, and is located at a greater distance from the battery cell stack than the pressing member.

[0007] The second perspective, in addition to the first perspective, has the following further characteristics: The load-supporting member and the pressing member are The image when the load-bearing member is projected onto the battery cell stack, The image when the pressing member is projected onto the battery cell stack and They are arranged so that they do not overlap each other.

[0008] The third perspective, in addition to the first perspective, has the following further characteristics: The connecting member is It has lower rigidity than load-bearing members.

[0009] The fourth perspective, in addition to the first perspective, has the following further characteristics: The connecting member is A load-supporting member, the first connecting portion which is a part of the side facing the battery cell stack, The second connecting portion, which is a part of the pressing member that faces the battery cell stack, They are linked together.

[0010] The fifth perspective has the following additional characteristics in addition to any one of the first through fourth perspectives: A buffer member is placed between the battery cell stack and the pressing member. It is equipped with. [Effects of the Invention]

[0011] From the first perspective, since the load-supporting member is positioned further away from the pressing member, the load is more easily applied to the load-supporting member. The load-supporting member deforms toward the battery cell stack when subjected to a load, but because the load-supporting member is separated from the battery cell stack, the two do not come into contact, and the transmission of load from the load-supporting member to the battery cell stack is suppressed.

[0012] From a second perspective, the load-supporting member and the pressing member are arranged so that they "do not overlap" (details of the configuration will be described later). This makes it less likely for the load-supporting member and the pressing member to come into contact when the load-supporting member deforms toward the battery cell stack. Therefore, load transmission to the battery cell stack via the pressing member can be suppressed.

[0013] From a third perspective, the connecting member is less rigid than the load-bearing member. As a result, the less rigid connecting member deforms upon receiving the load transmitted from the load-bearing member, absorbing energy. Consequently, the load is less likely to be transmitted to the pressing member, and the transmission of load to the battery cell stack via the pressing member can also be suppressed. Furthermore, if the connecting member can be made of a less rigid 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] From a fourth perspective, the connecting member "connects" the load-supporting member and the pressing member from below (details of the configuration will be described later). This allows for a greater degree of deformation of the load-supporting member. In other words, by connecting from below, the clearance between the load-supporting member and the pressing member can be reduced by the thickness of the load-supporting member compared to when there is no connection from below, which in turn leads to a reduction in the thickness of the battery pack.

[0015] According to the fifth aspect, a buffer member is interposed between the pressing member and the battery cell laminate. As a result, not only does the fixing degree between the battery cell laminate and the pressing member increase, but also a space between the pressing member and the battery cell laminate, which is necessary for the bottom surface connection, can be secured.

Brief Description of the Drawings

[0016] [Figure 1] It is a schematic diagram of a vehicle equipped with the battery pack according to the embodiment. [Figure 2] It is a cross-sectional view showing the configuration of the battery pack according to the embodiment. [Figure 3] It is a perspective view showing the configuration of the battery case according to the embodiment. [Figure 4] It is a cross-sectional view of the battery pack for explaining the operation and effects. [Figure 5] It is a schematic diagram for explaining the operation and effects. [Figure 6] It is a plan view showing a modification example of the battery case according to the embodiment.

Modes for Carrying Out the Invention

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

[0018] 1. Main Configuration of the Battery Case FIG. 1 is a schematic diagram of a vehicle 1 equipped with a battery pack 10 according to the embodiment. Generally, the battery pack 10 is mounted under the floor of the vehicle 1. The battery pack 10 is used, for example, as a power source for electric vehicles such as BEV, PEV, and HEV.

[0019] Here, in FIG. 1, the FR direction indicated by the arrow is the direction when the vehicle 1 moves forward, the UP direction is the upward direction of the vehicle 1, and the LH direction is the left direction as seen from the passenger who gets on the vehicle 1, that is, the direction facing the front of the paper in the paper surface. Note that the arrows shown in FIGS. 2 and later have the same meaning.

[0020] Figure 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 Figure 2.

[0021] The battery pack 10 comprises a battery cell stack 20, which is composed of multiple battery cells stacked on top of each other, 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 shown as a roughly rectangular parallelepiped, with its stacking direction aligned with the LH direction. The battery case 30 comprises 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 31 is configured to cover the battery cell stack 20. The outer shell 31 does not completely enclose the battery cell stack 20, but rather has a partially open shape as shown in Figure 2.

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

[0024] The pressing member 33 is a member used to fix the battery cell stack 20 to the outer shell 31 so that the battery cell stack 20 does not move due to driving vibrations or the like. For example, the pressing member 33 is positioned above the battery cell stack 20 and presses the battery cell stack 20 toward the bottom of the outer shell 31.

[0025] Furthermore, as shown in Figure 2, a buffer member 40 may be interposed between the pressing member 33 and the battery cell stack 20. Alternatively, the buffer member 40 may be provided on the opposite side from where the pressing member 33 is installed, i.e., 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, which increases the degree of fixation between the battery cell stack 20 and the battery case 30.

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

[0027] Here, the positional relationship between the load-supporting member 32 and the pressing member 33 will be explained. Firstly, the load-supporting member 32 and the pressing member 33 are arranged to face each other in the same direction as the battery cell stack 20. Secondly, the load-supporting member 32 is positioned at a greater distance from the battery cell stack 20 than the pressing member 33.

[0028] Furthermore, it is preferable that the load-supporting member 32 and the pressing member 33 are arranged such that their images, when projected onto the battery cell stack 20, do not overlap (the reason for this will be explained later). Hereafter, this arrangement will be referred to as the "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 lower rigidity than the load-supporting member 32.

[0030] Furthermore, it is preferable that the connecting member 34 connects the first connecting portion 32a of the load-supporting member 32 and the second connecting portion 33a of the pressing member 33. Here, the first connecting portion 32a is a part of the load-supporting member 32 on the side facing the battery cell stack 20. The second connecting portion 33a is a part of the surface of the pressing member 33 on the side facing the battery cell stack 20. (Hereinafter, this type of connection will be referred to as "bottom connection"). As an example of bottom connection, a thin sheet metal patch can be used as the connecting member 34, and the first connecting portion 32a and the second connecting portion 33a can be connected by welding.

[0031] The material constituting the connecting member 34 is not limited to the thin sheet metal patch exemplified above; it may also be a resin material, a leather or cloth material, a sponge, or the like. As yet another example, as shown in (B) in Figure 2, the shape of the connecting member 34 may be such that it is curved in the direction toward the battery cell stack 20.

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

[0033] Figure 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 comprises an outer shell 31, a load-supporting member 32, a pressing member 33, and a connecting member 34 that connects the load-supporting member 32 and the pressing member 33. The battery cell stack 20 is housed inside, so the battery cell stack 20 is isolated from the outside.

[0034] 2. Challenges and their effects In the prior art (for example, Patent Document 1), there is no member corresponding to the load-supporting member 32 in this disclosure, and the load from the UP direction is easily transmitted to the battery cell via the battery case and cushioning member. The fact that the load is easily transmitted to the battery, that is, that the battery is easily damaged, means that the battery life may be shortened.

[0035] Figure 4 is a cross-sectional view of a battery pack 10 for illustrating the operation and effects of the present disclosure. The present disclosure solves the above-mentioned problems by the following operation. In the present disclosure, the load support member 32 is positioned further from the battery cell stack 20 than the pressing member 33, so the load is easily applied to the load support member. The load support member 32 deforms toward the battery cell stack 20 when subjected to a load, but since the load support member 32 is spaced apart from the battery cell stack 20, the two do not come into contact, and the transmission of load from the load support member 32 to the battery cell stack 20 is suppressed.

[0036] In this case, if the load-supporting member 32 and the pressing member 33 are arranged so as not to overlap, when the load-supporting member 32 deforms toward the battery cell stack 20 under load, the load-supporting member 32 and the pressing member 33 are less likely to come into contact. Therefore, since the transmission of load to the battery cell stack 20 via the pressing member 33 can be suppressed, it is more preferable if the load-supporting member 32 and the pressing member 33 are arranged so as not to overlap.

[0037] Here, if the connecting member 34 has lower rigidity compared to the load-supporting member 32, the low-rigidity connecting member 34 deforms upon receiving the load transmitted from the load-supporting member 32, absorbing energy. As a result, the load is less likely to be transmitted to the pressing member 33, and the transmission of load to the battery cell stack 20 via the pressing member 33 can also be suppressed. Therefore, it is preferable for the connecting member 34 to have low rigidity. Furthermore, if the connecting member 34 can be made of a low-rigidity material, 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.

[0038] The effect of connecting the load-supporting member 32 and the pressing member 33 by a bottom connection of the connecting member 34 will be explained using Figure 5. Here, the distance in the UP direction between the load-supporting member 32 and the pressing member 33 is Δ, and the thickness of the load-supporting member 32 is t. In the figure, the dashed lines represent the state before receiving a load (before deformation), and the solid lines represent the state after receiving a load and deformation.

[0039] First, let's consider the case where the connecting member 34 is not connected at the bottom, as shown in (A) in Figure 5. In this case, when a load is applied to 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 the load support member 32 and the pressing member 33, creating resistance. The creation of resistance means that the load is transmitted to the pressing member 33, and as a result, the load is more easily transmitted to the battery cell stack 20.

[0040] On the other hand, let's consider the case where the members are connected at the bottom, as shown in (B) in Figure 5. Even when the load-supporting member 32 has deformed by Δ, the connecting member 34 is not sandwiched between the load-supporting member 32 and the pressing member 33, and no resistance is generated as a result. In this case, as the deformation progresses further and the deformation reaches Δ+t, the upper end of the load-supporting member 32 and the upper end of the pressing member 33 align. At this point, if the load acts over a wide area, the load begins to act directly on the pressing member 33, so the load can act on the pressing member 33 at the point of deformation Δ+t. In other words, the deformation Δ+t can be said to be the maximum possible deformation, assuming that the load is not transmitted to the pressing member 33.

[0041] In other words, when the bottom is connected, there is room for deformation up to the maximum possible value Δ+t, whereas when the bottom is not connected, the deformation is limited to Δ. This means that when the bottom is connected, the room for deformation can be increased by the thickness t of the load-supporting member 32 compared to when the bottom is not connected. To put it another way, to achieve the same allowable deformation, connecting the bottom reduces the distance Δ by the thickness t of the load-supporting 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 between the second connecting portion 33a and the battery cell stack 20 necessary for lower connection can be secured.

[0043] Due to the effects described above, this disclosure reduces the risk of damage to the battery cell stack 20 and, consequently, contributes to extending the lifespan of the vehicle battery.

[0044] 3. Variant In Figure 3, an example is shown in which one pressing member 33 is placed in the center of the battery case 30, and connecting members 34 and load-supporting members 32 are arranged around it. However, other embodiments are also possible as long as the effects of this disclosure can be achieved. Several modified examples that can achieve the effects of this disclosure are shown below.

[0045] 3-1. First variation Figure 6(A) is a plan view of a first modified example of the battery case 30 according to the embodiment, viewed from above in the UP direction. In the example shown in Figure 5, the load-supporting member 32 is separated into two parts, and connecting members 34 and load-supporting members 32 are arranged around each part. In other words, the load-supporting member 32 has a Japanese character shape, and load-supporting members 32 and connecting members 34 are arranged in shapes corresponding to its two openings. Thus, the pressing member 33 may be separated into multiple parts, and even in that case, the effects of this disclosure will be achieved.

[0046] 3-2. Second variation Figure 6(B) is a plan view of a second modified example of the battery case 30 according to the embodiment, viewed from above in the UP direction. In the example shown in Figure 6, the load-supporting member 32 is not completely enclosed by the connecting member 34 and the load-supporting member 32, and its end extends to the end of the battery case 30. Alternatively, the load-supporting member 32 is separated into two parts, and a load-supporting member 32 and a connecting member 34 with shapes corresponding to the open part are arranged therein. Thus, the load-supporting member 32 may be separated into multiple parts, and even in that case, the effects of this disclosure are still achieved. [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 housing a stack of battery cells, which consists of multiple battery cells stacked together, A pressing member for pressing the battery cell stack, A load-supporting member that is spaced apart from the aforementioned battery cell stack, A connecting member that connects the pressing member and the load-supporting member. Equipped with, The pressing member is, Arranged to face the aforementioned battery cell stack, The aforementioned load-supporting member is The battery cell stack is positioned so as to face the pressing member in the same direction as the battery cell stack, and is positioned at a greater distance from the battery cell stack than the pressing member. The aforementioned connecting member is Lower rigidity than the aforementioned load-supporting member Battery case.

2. A battery case according to claim 1, The load-supporting member and the pressing member are, The image obtained when the load-supporting member is projected onto the battery cell stack, The image when the pressing member is projected onto the battery cell stack and They are arranged so that they do not overlap each other. Battery case.

3. A battery case according to claim 1 or 2, A buffer member disposed between the battery cell stack and the pressing member. Furthermore, it is equipped with Battery case.

Images