Vehicle battery pack structure

Abstract

To provide a structure of a vehicular battery pack, in which torsional rigidity is ensured while a battery pack is lightened in weight and the deformation of a battery case due to side collision, etc. can be suppressed.SOLUTION: A battery case 10 of a battery pack 1 includes a bottom face 12 and a side wall 13 projecting above a vehicle from each of both sides of the bottom face 12 and extending in a front-back direction. An inner cross member 20 extending in a width direction is provided inside the battery case 10, and the end of an edge of the inner cross member 20 outside in the width direction is joined to the inner face of the side wall 13.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present invention relates to a structure of a vehicle battery pack. [Background technology]

[0002] An electric vehicle includes a battery pack, as disclosed in, for example, Patent Document 1. The battery pack includes a battery case that houses a battery module, and the battery case is fixed to the underside of a floor portion of the vehicle body. In order to extend the driving range of an electric vehicle, it is necessary to increase the capacity of the battery pack. Therefore, there is a demand for a larger battery pack.

[0003] On the other hand, in order to avoid the weight increase caused by the enlargement of the battery pack, the battery case is required to have a compact structure while ensuring a certain rigidity and strength. For example, the battery mounting structure provided on the vehicle body disclosed in Patent Document 1 includes a rocker that is a vehicle body frame member, and a center tunnel that extends in the vehicle front-rear direction at the center in the vehicle width direction between the left and right rockers, and further includes a plurality of cross members provided between the rocker and the center tunnel at intervals. The ends of the cross members are joined to the rocker and the center tunnel. A bottom plate is provided on the lower surface side of the center tunnel and the cross member, and a battery stack is arranged on the bottom plate. This configuration expands the mounting space for the battery stack. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2018-202946 A Summary of the Invention [Problem to be solved by the invention]

[0005] By providing a cross member as in the above example, it is possible to ensure a certain degree of rigidity of the battery mounting structure while ensuring the mounting space for the battery stack. On the other hand, the cross member in the above example is provided with a flange protruding forward from the front wall, a flange protruding rearward from the rear wall, and a flange protruding upward from the top surface, and the flanges are joined to the rocker and the center tunnel. Since the flanges are provided, for example, a corner formed by the front wall of the cross member and the flange may become a starting point of deformation when a side collision (hereinafter, a side impact) occurs in which an object or the like strikes the side of the vehicle body from the outside in the vehicle width direction. Therefore, with the structure in the above example, it may be difficult to suppress deformation of the battery case due to a side impact or the like.

[0006] In addition, as the battery pack becomes larger, the area occupied by the battery pack under the floor increases, and there are cases where it is not possible to secure space to place a framework member for reinforcing the floor. Therefore, the battery pack is also required to have torsional rigidity. In the structure of the above example, there is room for improvement in terms of reducing the weight of the battery pack while ensuring torsional rigidity and suppressing deformation of the battery case due to a side collision or the like.

[0007] The present invention has been made to solve the above-mentioned problems, and its object is to provide a vehicle battery pack structure that is lightweight while ensuring torsional rigidity, and can suppress deformation of the battery case due to a side collision, etc. [Means for solving the problem]

[0008] The vehicle battery pack structure according to the present invention for achieving the above object includes a battery case attached to the vehicle underside of a floor of a vehicle body. The battery case in the vehicle battery pack structure includes a plate-shaped bottom surface portion extending in the vehicle longitudinal direction, and sidewall portions protruding from both sides in the vehicle width direction of the bottom surface portion toward the vehicle upper side and extending in the vehicle longitudinal direction, and an inner cross member extending in the vehicle width direction is provided within the battery case, and an edge of an outer end portion in the vehicle width direction of the inner cross member is joined to an inner surface of the sidewall portion via a plate-shaped first reinforcing member. a vehicle front-rear direction length of the first reinforcing member is set to be longer than a vehicle front-rear direction length of the inner cross member, a front flange protruding toward the front of the vehicle is provided at a front lower part of the inner cross member, and a rear flange protruding toward the rear of the vehicle is provided at a rear lower part of the inner cross member, the front flange and the rear flange are joined to the bottom surface portion, a vehicle width direction outer end of the front flange and a vehicle width direction outer end of the rear flange are disposed at a distance from the side wall portion in the vehicle width direction, and a second reinforcing member is joined to a corner portion formed by the side wall portion and the bottom surface portion, and the second reinforcing member connects each of the front flange and the rear flange to a front portion and a rear portion of the first reinforcing member, There are. Effect of the Invention

[0009] According to the present invention, it is possible to ensure torsional rigidity while reducing the weight of a battery pack, and further to suppress deformation of the battery case due to a side collision or the like. [Brief description of the drawings]

[0010] [Figure 1] 1 is a perspective view of a vehicle battery pack according to the present invention, as viewed from above the vehicle. [Diagram 2] 2 is a perspective view showing a state in which an upper case and a battery cell are removed from the battery case in FIG. 1. [Diagram 3] FIG. 2 is a cross-sectional view taken along the line AA in FIG. [Figure 4] FIG. 2 is a perspective view showing a cross section taken along the line AA in FIG. [Diagram 5] 2 is an enlarged cross-sectional view showing a part of the cross section taken along the line BB in FIG. 1; [Figure 6] 5 is an enlarged perspective view of the periphery of the outer member of FIG. 4. [Figure 7] FIG. 3 is a perspective view showing a cross section taken along an arrow CC in FIG. 2. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, one embodiment of the structure of a vehicle battery pack according to the present invention will be described with reference to the drawings (FIGS. 1 to 7). In the drawings, the direction of the arrow Fr indicates the front in the vehicle longitudinal direction. The "front (front end) and rear (rear end)" in the description of the embodiment correspond to the front and rear in the vehicle longitudinal direction. The directions of the arrows L and R indicate the left and right in the vehicle width direction. In addition, the "left and right" in the description of the present embodiment correspond to the left and right when an occupant in the vehicle cabin faces forward of the vehicle.

[0012] The vehicle battery pack 1 of this embodiment is disposed on the vehicle lower side of the floor portion of the vehicle body.

[0013] As shown in Figures 1 to 5, the battery pack 1 of this embodiment has a battery case 10 that accommodates battery cells 1A, a battery side member 30 provided on the outer side of the battery case 10 in the vehicle width direction, an inner cross member 20 arranged inside the battery case 10, and an outer cross member 25 attached to the outside of the lower case 11.

[0014] First, a description will be given of the battery case 10 of the battery pack 1. The battery case 10 is disposed on the vehicle lower side of a floor panel (not shown) of the floor portion of the vehicle body, and is fixed to a side sill (not shown) or the like via a battery side member 30. As shown in FIG. 1, the battery case 10 has a lower case 11 and an upper case 17.

[0015] As shown in Fig. 2, the lower case 11 has a bottom surface portion 12, side wall portions 13, a front wall portion 14, and a rear wall portion 15. The bottom surface portion 12 is a portion on which the battery cells 1A are installed, and has a generally rectangular shape extending in the vehicle front-rear direction. The side wall portions 13 are provided on both outer sides of the bottom surface portion 12 in the vehicle width direction, protrude upward from the outer ends of the bottom surface portion 12 in the vehicle width direction, and extend in the vehicle front-rear direction. A lower outer flange 13a protruding outward in the vehicle width direction is provided at the upper end of the side wall portion 13.

[0016] The front wall portion 14 protrudes from the front end of the bottom surface portion 12 upward in the vehicle and extends in the vehicle width direction. In addition, the outer portion of the front wall portion 14 in the vehicle width direction is connected to the front portion of the side wall portion 13. A bracket 75 or the like that is connected to a framework member such as a front side member is joined to the front surface of the front wall portion 14. The rear wall portion 15 protrudes from the rear end of the bottom surface portion 12 upward in the vehicle and extends in the vehicle width direction. In addition, the outer portion of the rear wall portion 15 in the vehicle width direction is connected to the rear portion of the side wall portion 13. A front flange 14a that protrudes forward of the vehicle and extends in the vehicle width direction is provided at the upper end of the front wall portion 14 of the lower case 11, and a rear flange 15a that protrudes rearward of the vehicle and extends in the vehicle width direction is provided at the upper end of the rear wall portion 15.

[0017] As shown in FIG. 1, the upper case 17 is a lid-like member that covers the lower case 11 from above the vehicle. The upper case 17 in this example has a top surface portion 18, side walls 19, a front wall portion 19a, and a rear wall portion 19b. The top surface portion 18 is disposed at an interval on the vehicle upper side of the bottom surface portion 12 of the lower case 11, and is disposed at a slight interval from the lower surface of the floor panel 71, and has a substantially rectangular shape extending in the vehicle front-rear direction. The side walls 19 of the upper case 17 are provided on both outer sides of the top surface portion 18 in the vehicle width direction, protrude from the outer end of the top surface portion 18 in the vehicle width direction toward the lower side of the vehicle, and extend in the vehicle front-rear direction. The lower end of the side walls 19 of the upper case 17 is provided with an upper outer flange 18a that protrudes outward in the vehicle width direction. The upper outer flange 18a is fastened to the lower outer flange 13a by a bolt or the like.

[0018] The front wall 19a of the upper case 17 protrudes downward from the front end of the top surface 18 and extends in the vehicle width direction. The outer side of the front wall 19a in the vehicle width direction is connected to the front part of the side wall 19. The rear wall 19b of the upper case 17 protrudes downward from the rear end of the top surface 18 and extends in the vehicle width direction. The outer side of the rear wall 19b in the vehicle width direction is connected to the rear part of the side wall 19. The front wall 19a and the rear wall 19b of the upper case 17 are each provided with a flange 19c, similar to the front wall 14 and the rear wall 15 of the lower case 11. The flanges 19c of the upper case 17 are fastened to the front flange 14a and the rear flange 15a of the lower case 11 by bolts or the like, respectively.

[0019] As shown in Figures 2 to 7, the inner cross member 20 is a member extending in the vehicle width direction, and the lower part of the inner cross member 20 is joined to the bottom surface portion 12 of the lower case 11, and the outer end portion of the inner cross member 20 in the vehicle width direction abuts against the inner surface of the side wall portion 13, and the edge of the end portion is joined to the inner surface.

[0020] In this embodiment, a plurality of inner cross members 20 are arranged at intervals from one another in the vehicle longitudinal direction. Although not shown in the figure, the battery cell 1A is arranged between the inner cross members 20 arranged in the vehicle longitudinal direction. Each inner cross member 20 has a predetermined width in the vehicle longitudinal direction, and its height in the vehicle vertical direction is set to be longer than this width. In addition, the inner cross member 20 and the bottom surface portion 12 of the lower case 11 form a closed cross-sectional structure when viewed in the vehicle width direction.

[0021] In this embodiment, three inner cross members 20 are provided inside the battery case 10, and the foremost inner cross member 20 is disposed on the vehicle rear side of the front wall portion 14 of the lower case 11 with a gap therebetween. The middle inner cross member 20 is disposed on the vehicle rear side of the foremost inner cross member 20 with a gap therebetween, and the last inner cross member 20 is disposed on the vehicle rear side of the middle inner cross member 20 with a gap therebetween. The rear wall portion 15 of the lower case 11 is disposed on the vehicle rear side of the last inner cross member 20 with a gap therebetween.

[0022] The inner cross member 20 of this embodiment has an intermediate member 21 and left and right outer members 22. As shown in Fig. 2 and Fig. 5, the intermediate member 21 is a member extending in the vehicle width direction as a whole, and has a front panel 21A and a rear panel 21B arranged at the front and rear of the vehicle, which are joined to each other. As shown in Figs. 5 to 7, the front panel 21A has a front wall 21a facing the front of the vehicle, an upper surface portion 21c protruding from the upper end of the front wall 21a toward the rear of the vehicle, and an upper front flange 21b protruding from the front end of the upper surface portion 21c toward the upper side of the vehicle. In addition, a lower front flange (front flange) 21d protruding from the lower end toward the front of the vehicle is provided at the lower end of the front wall 21a of the front panel 21A.

[0023] 5 to 7, the rear panel 21B has a rear wall 21e facing the rear of the vehicle, and an upper rear flange 21f protruding from an upper end of the rear wall 21e toward the upper side of the vehicle. In addition, a lower rear flange (rear flange) 21g is provided at the lower end of the rear wall 21e of the rear panel 21B, protruding from the lower end toward the rear of the vehicle.

[0024] The upper front flange 21b of the front panel 21A and the upper rear flange 21f of the rear panel 21B are joined by spot welding or the like to form the intermediate member 21. Furthermore, the lower front flange 21d of the front panel 21A and the lower rear flange 21g of the rear panel 21B are joined to the bottom surface portion 12 of the lower case 11 by spot welding or the like. As a result, the intermediate member 21 and the bottom surface portion 12 form the above-mentioned closed cross-sectional structure. Furthermore, an opening is formed at an end portion of the intermediate member 21 in the vehicle width direction.

[0025] The distance in the vehicle up-down direction from the bottom surface portion 12 of the lower case 11 to the upper surface portion 21c of the intermediate member 21 is set to be longer than the distance in the vehicle front-rear direction between the front wall 21a and the rear wall 21e of the intermediate member 21. That is, the intermediate member 21 has a U-shaped cross section extending in the vehicle up-down direction when viewed in the vehicle width direction, and the above-mentioned closed cross-sectional structure extends in the vehicle up-down direction.

[0026] As shown in FIGS. 5 to 7, the outer member 22 is joined to an outer portion of the intermediate member 21 in the vehicle width direction, and an outer end of the outer member 22 is joined to the side wall portion 13 of the lower case 11.

[0027] The outer member 22 is an annular member formed by joining two members and penetrating in the vehicle width direction. The cross-sectional shape as viewed in the vehicle width direction is an ellipse extending in the vertical direction on the vehicle. The inner side in the vehicle width direction of the outer member 22 is joined to the front wall of the front panel and the rear wall of the rear panel of the intermediate member 21 by spot welding or the like. That is, the inner side in the vehicle width direction of the outer member 22 is inserted into an opening at the outer end in the vehicle width direction of the intermediate member 21, and is sandwiched and held between the front wall and the rear wall of the intermediate member 21 and welded.

[0028] The lower part of the outer member 22 is disposed at a distance from the bottom surface portion 12 on the vehicle upper side, and extends substantially parallel to the bottom surface portion 12. The upper end of the outer member 22 extends so as to incline upwardly of the vehicle as it approaches the outer side in the vehicle width direction. That is, the outer member 22 is substantially trapezoidal in front view, as shown in Figs. 3, 4 and 6. By configuring the outer member 22 as described above, it is easy to manufacture. In addition, the edge of the end part of the outer part in the vehicle width direction of the outer member 22 is joined in contact with the side wall part 13 of the lower case 11 via a first reinforcing member 51 described later.

[0029] By abutting the edge of the outer end of the inner cross member 20 in the vehicle width direction against the inner surface of the inner wall portion 13, the cross-sectional shape of the end, i.e., the cross-sectional shape of the outer end of the annular outer member 22 in the vehicle width direction (a substantially elliptical shape with the major axis in the vehicle vertical direction) can be maintained, and rigidity in the vehicle vertical direction can be further improved. Therefore, deformation due to impact load due to a side collision, etc. can be suppressed.

[0030] Furthermore, if a flange is integrally formed on the outer end of the outer member 22 of the inner cross member 20, for example by bending it forward and backward of the vehicle, the bent portion (bending point or inflection point) may become a starting point of deformation and promote the deformation. In contrast, the present embodiment has a structure without such a flange, and therefore there is no starting point of deformation, so the inner cross member 20 can ensure higher rigidity against the load input of a side collision.

[0031] In addition, since there is no processing step for forming the flanges, the manufacturing process for the inner cross member 20 can be simplified. In addition, in this embodiment, since the inner cross member 20 is composed of the intermediate member 21 and the left and right outer members 22, it can be applied to battery cases 10 having different dimensions in the vehicle width direction simply by changing the mounting positions of the left and right outer members 22.

[0032] The vehicle width direction outer end of the inner cross member 20 is joined to the inner surface of the side wall 13 via a plate-shaped first reinforcing member 51. In this example, as described above, the edge of the end of the vehicle width direction outer part of the outer member 22 is joined to the side wall 13 via the first reinforcing member 51 as shown in Figures 2 and 7.

[0033] In this example, the first reinforcing member 51 is a plate-shaped member extending in the vertical and longitudinal directions of the vehicle, and the length of the first reinforcing member 51 in the longitudinal direction of the vehicle is set longer than the length of the inner cross member 20 in the longitudinal direction of the vehicle.

[0034] An outer surface of the first reinforcing member 51 is joined to an inner surface of the side wall portion 13 by spot welding or the like. In this example, a front end of the first reinforcing member 51 is disposed further forward of the front end of the outer member 22 in the vehicle, and a rear end of the first reinforcing member 51 is disposed further rearward of the rear end of the outer member 22 in the vehicle.

[0035] By providing the first reinforcing member 51, it is possible to improve the strength and rigidity of the side wall portion 13 and further suppress deformation of the battery case 10. Furthermore, when an impact load due to a side collision is input, stress is likely to concentrate on the outer end portion in the vehicle width direction of the outer member 22 of the inner cross member 20. In contrast, by providing the first reinforcing member 51, the stress can be dispersed to the periphery via the first reinforcing member 51, and it is possible to suppress localized concentration (single-point concentration) of stress on the battery case 10.

[0036] 5 to 7, a lower front flange 21d protruding toward the front of the vehicle is provided at a lower part of the front side of the inner cross member 20, and a lower rear flange 21g protruding toward the rear of the vehicle is provided at a lower part of the rear side of the inner cross member 20. In this embodiment, the lower front flange 21d and the lower rear flange 21g are provided at the lower part of the intermediate member 21, as described above. In this embodiment, the vehicle width direction outer end of the lower front flange 21d and the vehicle width direction outer end of the lower rear flange 21g are disposed with a gap in the vehicle width direction relative to the side wall portion 13, as shown in FIG.

[0037] Furthermore, a second reinforcing member 52 is joined to a corner formed by the side wall portion 13 and the bottom surface portion 12 of the lower case 11 of this embodiment. A slight gap is provided between the corner and the second reinforcing member 52. The second reinforcing member 52 connects the lower front flange 21d and the lower rear flange 21g to the front and rear portions of the first reinforcing member 51, respectively.

[0038] 5 to 7, the second reinforcing member 52 is a metal member having a side plate portion 52a arranged along the side wall portion 13 and a bottom plate portion 52b arranged on the bottom surface portion 12, the side plate portion 52a and the bottom plate portion 52b being integrally formed. The second reinforcing member 52 extends in the vehicle longitudinal direction and is disposed between the inner cross members 20 arranged side by side in the vehicle longitudinal direction. In this example, the second reinforcing members 52 are disposed between the foremost inner cross member 20 and the middle inner cross member 20, between the middle inner cross member 20 and the rear inner cross member 20, and between the rear inner cross member 20 and the rear wall portion 15.

[0039] The side plate portion 52a extends in the vehicle front-rear direction and is joined to the side wall portion 13 by spot welding or the like. A front portion of the side plate portion 52a is joined to a lower portion of a rear portion of the corresponding first reinforcing member 51 by spot welding or the like, and a rear portion of the side plate portion 52a is joined to a front portion of the corresponding first reinforcing member 51. A notch 52c cut downward from an upper end is provided in an intermediate portion of the side plate portion 52a in the vehicle front-rear direction.

[0040] The bottom plate portion 52b abuts the bottom surface portion 12 and extends in the fore-and-aft direction of the vehicle, with the front portion of the bottom surface portion joined to the lower rear flange of the corresponding inner cross member 20 by spot welding or the like, and the rear portion of the bottom surface portion joined to the lower front flange of the corresponding inner cross member 20 or the like.

[0041] For example, as shown in FIG. 7, a side plate portion 52a of a second reinforcing member 52 disposed between the foremost inner cross member 20 and the middle inner cross member 20 is joined to the side wall portion 13 by spot welding or the like, and further, a front portion of the side plate portion 52a is joined to a rear portion of the first reinforcing member 51 to which the foremost inner cross member 20 is joined, and a rear portion of the side plate portion 52a is joined to a front portion of the first reinforcing member 51 to which the middle inner cross member 20 is joined. Similarly, a front portion of a bottom plate portion 52b is joined to an upper surface of a lower rear flange of the foremost inner cross member 20, and a rear portion of the bottom plate portion 52b is joined to an upper surface of a lower rear flange of the middle inner cross member 20. Further, a rear portion of the bottom plate portion 52b of the second reinforcing member 52 between the last inner cross member 20 and the rear wall portion 15 is joined to a bottom surface portion 12 located on the vehicle front side of the rear wall portion 15.

[0042] By providing the second reinforcing member 52, it becomes possible for the inner cross member 20 to indirectly join the bottom portion 12 and the side wall portion 13, and further, by forming a gap at the corner, it is possible to avoid concentration of stress at the corner.

[0043] The second reinforcing member 52 is configured to connect the inner cross members 20 arranged side by side in the vehicle longitudinal direction and to connect the front wall portion 14 and the rear wall portion 15. This makes it possible to improve the strength and rigidity of the battery case 10 at positions other than where the inner cross members 20 are provided. Even if an impact load such as a side collision is input to the side wall portion 13 located between the foremost inner cross member 20 and the middle inner cross member 20, the side wall portion 13 located between the middle inner cross member 20 and the last inner cross member 20, and the side wall portion 13 located between the next inner cross member 20 and the rear wall portion 15, it is possible to transmit the impact load to the adjacent inner cross members 20.

[0044] 2 and 6, a battery side member 30 which is a hollow member and extends in the vehicle front-rear direction is provided on the vehicle width direction outer side of the side wall portion 13 of the lower case 11 of the battery case 10. The battery side member 30 has a substantially rectangular closed cross-sectional structure extending in the vehicle up-down direction when viewed in the vehicle front-rear direction. The structure of the battery side member 30 will be described below.

[0045] 2 and 6, the battery side member 30 has a first side member 31 extending in the vehicle front-rear direction and a second side member 40 extending in the vehicle front-rear direction. The first side member 31 and the second side member 40 are joined to each other, the first side member 31 is joined to a side sill (not shown), and the second side member 40 is joined to an outer surface of a side wall portion 13 of a lower case 11 of the battery case 10.

[0046] The first side member 31 is a hollow rectangular parallelepiped member formed of a material containing aluminum, for example, and extending in the vehicle longitudinal direction. The cross section of the first side member 31 (cross section as viewed in the vehicle longitudinal direction) is a rectangle extending in the vehicle width direction. In this example, the first side member 31 is formed by pultrusion molding of an aluminum alloy. The first side member 31 has an upper flange 32 and a lower flange 33, which are joined to the second side member 40 by bolts or the like.

[0047] As shown in Fig. 6, the second side member 40 has an outer panel 41 made of sheet metal extending in the vehicle front-rear direction, and an inner panel 45 made of sheet metal extending in the vehicle front-rear direction. The outer panel 41 is formed by bending a single sheet of metal material. The inner panel 45, like the outer panel 41, is also formed by bending a single sheet of metal material. The outer panel 41 and the inner panel 45 are joined together to form a rectangular closed cross-sectional structure extending in the vehicle up-down direction when viewed in the vehicle front-rear direction.

[0048] The length of the closed cross-sectional structure in the vertical direction of the vehicle is set to be equal to the length of the inner cross member 20 in the vertical direction of the vehicle. As described above, the battery side member 30, which is a hollow member, is joined to the outside of the side wall portion 13. The vehicle width direction inner surface of the battery side member 30, the side wall portion 13, and the first reinforcing member 51 may be joined in three pieces in an overlapping state.

[0049] As shown in Figs. 6 and 7, a hat-shaped member 80 having a hat-shaped cross section as viewed in the vehicle longitudinal direction is joined to the inside of the closed cross-sectional structure of the second side member 40 of the battery side member 30. The hat-shaped member 80 extends in the vehicle longitudinal direction so as to intersect with the inner cross member 20 and the first reinforcing member 51. In this example, the front end of the hat-shaped member 80 is located further forward in the vehicle than the front end of the first reinforcing member 51, and the rear end of the hat-shaped member 80 is located further rearward in the vehicle than the rear end of the first reinforcing member 51. The joint surface of the hat-shaped member 80 on the inner side in the vehicle width direction is joined to the outer surface of the side wall portion 13 by spot welding or the like. In addition, a lower portion of the joint surface is joined to a position corresponding to the notch 52c of the side plate portion 52a of the second reinforcing member 52 by spot welding or the like.

[0050] By providing the battery side member 30, the rigidity of the side wall portion 13 can be improved. Furthermore, the impact load received by the battery side member 30 is effectively transmitted to the inner cross member 20 via the hat-shaped member 80. By supporting the battery side member 30 with the inner cross member 20 so that it can deform as intended (in accordance with design) to absorb the impact, the battery side member 30 and the inner cross member 20 work together to effectively absorb the impact load due to a side collision.

[0051] In this embodiment, an outer cross member 25 is provided on the lower surface side of the bottom surface portion 12 of the lower case 11. The outer cross member 25 extends in the vehicle width direction. In this example, a plurality of outer cross members 25 are arranged at intervals from each other in the vehicle front-rear direction so as to correspond to the inner cross members 20. By sandwiching the bottom surface portion 12 between the inner cross member 20 and the outer cross member 25, it is possible to improve the rigidity of the battery case 10.

[0052] The description of the present embodiment is merely an example for explaining the present invention, and does not limit the invention described in the claims. Furthermore, the configuration of each part of the present invention is not limited to the above embodiment, and various modifications are possible within the technical scope described in the claims.

[0053] In this embodiment, the inner cross member 20 is made up of the intermediate member 21 and the left and right outer members 22, but is not limited to this. It may be made up of a single member. [Explanation of symbols]

[0054] 1 Battery pack 1A Battery Cell 10 Battery case 11 Lower case 12 Bottom part 13 Side wall 13a Lower outer flange 14 Front wall 14a Front flange 15 Rear wall 15a Rear flange 17 Upper case 18 Top section 18a Upper outer flange 19 Side wall 19a Front wall 19b Rear wall 20 Inner cross member 21 Intermediate parts 21A Front Panel 21a Front wall 21b Upper front flange 21c Top part 21d Lower front flange (front flange) 21B Rear Panel 21e back wall 21f Upper rear flange 21g Lower rear flange (rear flange) 22 Outer member 25 Outer cross member 30 Battery side member 31 First side member 32 Upper flange 33 Lower flange 40 Second side member 41 Outer Panel 45 Inner Panel 51 First reinforcing member 52 Second reinforcing member 52a Side plate part 52b Bottom plate part 52c Notch 75 Bracket 80 Hat-shaped component

Claims

1. A vehicle battery pack structure having a battery case attached to a vehicle underside of a floor portion of a vehicle body, The battery case has a plate-shaped bottom surface portion extending in a vehicle front-rear direction, and side wall portions protruding upward from both sides of the bottom surface portion in a vehicle width direction and extending in the vehicle front-rear direction, An inner cross member extending in a vehicle width direction is provided within the battery case, and an edge of an outer end portion of the inner cross member in the vehicle width direction is joined to an inner surface of the side wall portion via a plate-shaped first reinforcing member, A length of the first reinforcing member in the vehicle front-rear direction is set to be longer than a length of the inner cross member in the vehicle front-rear direction, A front flange protruding toward the front of the vehicle is provided on a lower portion of a front side of the inner cross member, and a rear flange protruding toward the rear of the vehicle is provided on a lower portion of a rear side of the inner cross member, The front flange and the rear flange are joined to the bottom surface portion, a vehicle width direction outer end of the front flange and a vehicle width direction outer end of the rear flange are disposed with a gap in the vehicle width direction relative to the side wall portion, a second reinforcing member is joined to a corner portion formed by the side wall portion and the bottom surface portion; A structure of a vehicle battery pack, characterized in that the second reinforcing member connects each of the front flange and the rear flange to the front and rear portions of the first reinforcing member, respectively.

2. a battery side member having a closed cross-sectional structure when viewed in the vehicle front-rear direction and extending in the vehicle front-rear direction is provided on a vehicle width direction outer side of the side wall portion of the battery case, A length of the closed cross-sectional structure in the vehicle vertical direction is set equal to a length of the inner cross member in the vehicle vertical direction, A hat-shaped member having a hat-shaped cross section as viewed in the vehicle front-rear direction is joined to an inner side of the closed cross-sectional structure of the battery side member, 2. The vehicle battery pack structure according to claim 1, wherein the hat-shaped member extends in a front-rear direction of the vehicle so as to intersect with the inner cross member and the first reinforcing member.

3. A front wall portion protruding upward from the vehicle and extending in a vehicle width direction is provided at a front portion of the bottom surface portion, and a rear wall portion protruding upward from the vehicle and extending in the vehicle width direction is provided at a rear portion of the bottom surface portion, A plurality of the inner cross members are disposed in the battery case at intervals from one another in a vehicle front-rear direction, 2. The structure of a vehicle battery pack as described in claim 1, characterized in that the second reinforcing member is configured to connect the inner cross members adjacent to each other in the vehicle fore-and-aft direction and to connect the front wall portion and the rear wall portion.

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