Battery case structure

Abstract

This battery case structure 2 has a case 20 that is provided on the bottom of a vehicle 1, and that houses a battery 3. The case 20 has a rear wall 21 on the rear side. The rear wall 21 has a first wall 21a and a pair of second walls 21b provided at both ends in a vehicle width direction Xw of the first wall 21a. The second wall 21b extends in a direction inclined with respect to the first wall 21a. A length Lb in the vehicle width direction of the second wall 21b is less than a length La in the vehicle width direction of the first wall 21a, and a gas release hole 27 for exhausting gas inside the case 20 is provided at one or both of the pair of second walls 21b.

Description

Battery case structure

[0001] The present invention relates to a battery case structure.

[0002] The battery pack described in Patent Document 1 includes a case that houses a battery, and an opening is provided on the rear surface of the case for venting gas generated inside.

[0003] Japanese Patent Application Laid-Open No. 2021-140931

[0004] However, as disclosed in Patent Document 1, when a gas discharge hole is provided in the case, there is a risk that the rigidity of the case may decrease.

[0005] The problem to be solved by the present invention is to provide a battery case structure that can prevent a decrease in the rigidity of a case that houses a battery.

[0006] The present invention solves the above problem by providing a rear wall of the case having a first wall and a pair of second walls provided at each end of the first wall in the vehicle width direction, the second walls extending in a direction inclined relative to the first wall, the vehicle width length of the second walls being shorter than the vehicle width length of the first wall, and a gas release hole being provided in one or both of the pair of second walls.

[0007] According to the present invention, it is possible to obtain an effect of suppressing a decrease in the rigidity of a case that houses a battery.

[0008] 4 is a perspective view showing a state in which the battery case structure according to the present embodiment is attached to the body of a vehicle. FIG. 5 is a plan view of the battery case structure according to the present embodiment. FIG. 6 is a view of the battery case structure shown in FIG. 2 as seen from the rear side of the vehicle body. FIG. 7 is a cross-sectional perspective view showing a state in which the rear wall of the battery case structure shown in FIG. 3 is cut along line IV-IV. FIG. 8 is a perspective view of the second wall of the rear wall of the battery case structure shown in FIG. 2 as seen from diagonally below. FIG. 9 is a perspective view of the second wall of the rear wall of the battery case structure shown in FIG. 2 as seen from inside the case. FIG. 10 is a perspective view of the second wall of the rear wall of the battery case structure shown in FIG. 2 as seen from diagonally above.

[0009] An embodiment of the present invention will now be described with reference to the drawings. As shown in Fig. 1, a battery case structure 2 is provided on the bottom side of a lower portion of a body 10 of a vehicle 1. The battery case structure 2 is disposed between a pair of side sills 11 provided on the body 10. The battery case structure 2 has a case 20 that houses multiple batteries 3 (see Fig. 2) therein.

[0010] The detailed structure of the battery case structure 2 will be described with reference to Figures 2 to 7. In Figure 2, the left side of the drawing is the front side Df of the vehicle 1, and the right side of the drawing is the rear side Db of the vehicle 1. In addition, the upper side of Figure 2 is the right side DR of the vehicle 1, and the lower side is the left side DL of the vehicle 1. In the following description, the left-right direction on the drawing of Figure 2 is referred to as the front-rear direction Xf, and the direction perpendicular to the front-rear direction Xf is referred to as the vehicle width direction Xw.

[0011] As shown in FIG. 2 , the case 20 has a rear wall 21 on the rear side Db and a front wall 22 on the front side Df. A pair of side walls 23 extending in the front-rear direction Xf are provided between the rear wall 21 and the front wall 22. Specifically, one of the pair of side walls 23 is provided between an end of the right side DR of the rear wall 21 and an end of the right side DR of the front wall 22, and the other is provided between an end of the left side DL of the rear wall 21 and an end of the left side DL of the front wall 22. The space surrounded by the rear wall 21, the front wall 22, and the pair of side walls 23 constitutes a battery accommodating space 5 for accommodating the battery 3. That is, the battery accommodating space 5 is defined inside the pair of side walls 23. Note that, in the example shown in FIG. 2 , five batteries 3 are accommodated in the battery accommodating space 5, but the number of batteries 3 is not limited to this.

[0012] The rear wall 21 has a first wall 21a provided at the center of the rear wall 21 and a pair of second walls 21b provided at both ends of the first wall 21a in the vehicle width direction Xw. The second walls 21b extend in a direction inclined relative to the first wall 21a. Specifically, the pair of second walls 21b are inclined relative to the first wall 21a at an angle that widens toward the front side Df. Furthermore, the vehicle width direction length Lb of the second walls 21b is shorter than the vehicle width direction length of the first wall 21a.

[0013] 2 and 3, a pair of fastening brackets 26 are provided symmetrically on the upper part of the first wall 21a of the rear wall 21. Furthermore, a pair of second walls 21b of the rear wall 21 are each provided with a rear suspension bracket 25 that supports a rear suspension 32. The rear wall 21, rear suspension brackets 25, and fastening brackets 26 are integrally formed as a casting.

[0014] 3, the upper end of each of the pair of fastening brackets 26 is attached to the cross member 12 of the vehicle body 10. That is, the case 20 of the battery case structure 2 is connected to the vehicle body 10 in the vehicle up-down direction via the fastening brackets 26. This increases the rigidity of the cross member 12 of the vehicle body 10.

[0015] 3 and 4, a rear suspension 32 is attached to the rear suspension bracket 25 via a flat rear suspension pin 31. As shown in Fig. 3, the upper end of the rear suspension 32 is attached to the suspension attachment portion 13 of the cross member 12 of the vehicle body 10. Here, because the case 20 of the battery case structure 2 is connected to the vehicle body 10 via the fastening bracket 26, the rigidity of the rear suspension 32 attached between the vehicle body 10 and the case 20 of the battery case structure 2 is increased.

[0016] As shown in FIGS. 3 to 5 , each of the pair of second walls 21b is provided with two gas release holes 27 for discharging gas from inside the case 20. The gas release holes 27 are provided below the rear suspension bracket 25. As shown in FIG. 4 , the gas release holes 27 are covered with gas release hole covers 28. Note that the gas release hole covers 28 are omitted from FIGS. 2 , 3 , 5 , and 7 . In the present embodiment, the gas release holes 27 are provided in both of the pair of second walls 21b, but this is not limited thereto, and the gas release holes 27 may be provided in only one of the pair of second walls 21b. As shown in FIGS. 3 to 5 , each of the pair of second walls 21b is provided with two gas release holes 27, but this is not limited thereto, and the number of gas release holes 27 provided in one second wall 21b may be one, three, or more.

[0017] As shown in FIG. 6 , a plurality of first ribs 21b1 extending in the lateral direction Xt and a plurality of second ribs 21b2 extending in the vertical direction Xv are integrally formed on the inner side of the rear wall 21. The lateral direction Xt is a direction perpendicular to the vertical direction Xv, extends along the second wall 21b, and is parallel to the bottom surface of the case 20. Each gas release hole 27 is provided in a lattice-shaped region G defined between the first rib 21b1 and the second rib 21b2. That is, when a plurality of gas release holes 27 are provided in the second wall 21b, each of the plurality of gas release holes 27 is provided in one lattice-shaped region G. The second rib 21b2 is provided so as to incline toward the central axis 27a of the gas release hole 27. Specifically, the second rib 21b2 is inclined in a direction intersecting the central axis 27a of the gas release hole 27 inside the case 20. That is, the standing direction Xa of the second rib 21b2 is inclined with respect to the central axis 27a of the gas release hole 27, and if the second rib 21b2 is extended in the standing direction Xa, the second rib 21b2 and the central axis 27a of the gas release hole 27 will intersect inside the case 20. Furthermore, if the second rib 21b2 is not extended in the standing direction Xa, the second rib 21b2 and the central axis 27a of the gas release hole 27 may intersect.

[0018] As shown in FIG. 2 , the case 20 includes a pair of member members 24 that define the battery accommodating space 5 in the rearward side Db region inside the case 20. Each of the pair of member members 24 extends in the front-rear direction Xf. A single battery 3 is disposed between the pair of member members 24. As shown in FIGS. 2 , 6 , and 7 , a side wall 23 is connected to one outer end of each of the pair of second walls 21b, and a member member 24 is connected to the other inner end. As shown in FIG. 2 , the member member 24 is disposed between the battery 3 disposed on the rearmost side Db and the gas release hole 27. In the example shown in FIG. 6 , the height of the member member 24 is the same as the height of the upper end of the gas release hole 27, but this is not limited thereto. The height of the member member 24 may be any height as long as it is equal to or greater than the height of the upper end of the gas release hole 27. The height of the member member 24 is also lower than the height of the side wall 23. Therefore, a gap is formed between the upper surface of the member member 24 and the upper case (not shown) of the case 20. That is, the gas generated in the battery accommodating space 5 can flow through the gap above the member member 24 .

[0019] As described above, the rear wall 21 of the case 20 of the battery case structure 2 according to this embodiment includes a first wall 21a and a pair of second walls 21b provided at both ends of the first wall in the vehicle width direction Xw. The second walls 21b extend in a direction inclined relative to the first wall 21a, and the vehicle width direction length Lb of the second wall 21b is shorter than the vehicle width direction length La of the first wall 21a. One or both of the pair of second walls 21b is provided with a gas release hole 27 for discharging gas inside the case 20. Here, because the vehicle width direction length Lb of the second wall 21b is shorter than the vehicle width direction length La of the first wall 21a, when an external force, particularly a force in the fore-aft direction Xf, is applied to the rear wall 21, the degree of deflection of the second wall 21b is smaller than the degree of deflection of the first wall 21a. Furthermore, because the second wall 21b extends in a direction inclined relative to the first wall 21a, i.e., in a direction inclined relative to the vehicle width direction Xw and the front-rear direction Xf, the effect on the gas release holes 27 of the second wall 21b when an input in the vehicle width direction Xw is applied can be further reduced. Therefore, in the battery case structure 2 according to this embodiment, the provision of the gas release holes 27 in the second wall 21b can prevent a decrease in the rigidity of the case 20.

[0020] Furthermore, a plurality of first ribs 21b1 extending in the lateral direction Xt perpendicular to the up-down direction Xv and a plurality of second ribs 21b2 extending in the up-down direction Xv are integrally formed on the inside of the rear wall 21 of the battery case structure 2, and the gas release holes 27 are provided in a lattice region G defined between the first ribs 21b1 and the second ribs 21b2. As a result, each of the gas release holes 27 is surrounded by the first ribs 21b1 and the second ribs 21b2, and therefore, a decrease in the rigidity of the rear wall 21 due to the provision of the gas release holes 27 can be suppressed.

[0021] Furthermore, when a plurality of gas release holes 27 are provided, each of the plurality of gas release holes 27 is provided in one grid-shaped area G. This makes it possible to increase the rigidity around each of the gas release holes 27.

[0022] Furthermore, the second rib 21b2 is inclined in a direction intersecting the central axis 27a of the gas release hole 27 inside the case 20. That is, the second rib 21b2 is provided so as to be inclined toward the central axis 27a of the gas release hole 27 inside the case 20. As a result, the flow of gas flowing out from the gas release hole 27 to the outside of the case 20 is obstructed by the second rib 21b2 and temporarily stagnates, thereby preventing high-temperature gas from directly flowing out of the case 20. That is, because the gas flow is obstructed by the second rib 21b2, the momentum at which the gas is released or the temperature of the gas can be reduced before it flows out of the case 20.

[0023] The case 20 of the battery case structure 2 includes a pair of side walls 23 that extend in the front-rear direction Xf and define the battery accommodating space 5 on the inside, and a member member 24 that extends in the front-rear direction Xf and partitions the battery accommodating space 5. The side wall 23 is connected to one end of the second wall 21b, and the member member 24 is connected to the other end. As a result, the second wall 21b is supported by the side wall 23 and the member member 24, which increases the rigidity of the second wall 21b.

[0024] Furthermore, the member member 24 is provided between the battery 3 and the gas release hole 27, and the height of the member member 24 is equal to or greater than the height of the upper end of the gas release hole 27. As a result, the flow of gas generated in the battery 3 is obstructed by the member member 24 and temporarily retained there, preventing the high-temperature gas from directly flowing out of the case 20. In other words, the gas flow is obstructed by the member member 24, so that the temperature of the gas can be reduced before it flows out of the case 20.

[0025] Moreover, a rear suspension bracket 25 that connects to a rear suspension 32 of the vehicle 1 is provided above the gas release hole 27. This makes it possible to further increase the rigidity around the gas release hole 27.

[0026] REFERENCE SIGNS LIST 1 vehicle 2 battery case structure 3 battery 5 battery accommodating space 20 case 21 rear wall 21a first wall 21b second wall 21b1 first rib 21b2 second rib 23 side wall 24 member member 25 rear suspension bracket 27 gas release hole 32 rear suspension

Claims

1. A battery case structure provided at the lower part of a vehicle and having a case for accommodating a battery, wherein the case has a rear wall on the rear side of the vehicle, the rear wall has a first wall and a pair of second walls provided at both ends in the vehicle width direction of the first wall, the second wall extends in a direction inclined with respect to the first wall, and the vehicle width direction length of the second wall is shorter than the vehicle width direction length of the first wall, and a gas discharge hole for discharging gas inside the case is provided in one or both of the pair of second walls.

2. A plurality of first ribs extending in the lateral direction and a plurality of second ribs extending in the vertical direction are integrally formed inside the rear wall, and the gas discharge hole is provided in a grid-like region defined between the first rib and the second rib. The battery case structure according to claim 1.

3. When a plurality of the gas discharge holes are provided, each of the plurality of gas discharge holes is provided one by one in one of the grid-like regions. The battery case structure according to claim 2.

4. The second rib is inclined in a direction intersecting the central axis of the gas discharge hole inside the case. The battery case structure according to claim 2 or 3.

5. The case includes a pair of side walls extending in the front-rear direction and defining a battery accommodation space for accommodating the battery inside, and a member portion extending in the front-rear direction and partitioning the battery accommodation space, and the side wall is connected to one end of the second wall, and the member portion is connected to the other end. The battery case structure according to any one of claims 1 to 4.

6. The member portion is provided between the battery and the gas discharge hole, and the height of the member portion is equal to or higher than the height of the upper end of the gas discharge hole. The battery case structure according to claim 5.

7. In the second wall, a rear suspension bracket for supporting the rear suspension of the vehicle is provided above the gas discharge hole. The battery case structure according to any one of claims 1 to 6.

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