Battery case side wall

Abstract

To suppress damage to a battery case of an on-vehicle battery in the event of a side collision of a vehicle.SOLUTION: A case sidewall 28 of a battery case has a tubular portion 38 with a closed cross-sectional structure consisting of an upper wall 44, a lower wall 46, an inner wall 48 and an outer wall 50, an inner flange 40 and an outer flange 42. A first member 66, made of steel plate, forms the inner flange 40, an inner wall 48, an upper wall 44, an upper portion of outer wall 50a, and an outer flange 42, while a second member 68, made of steel plate, forms the outer flange 42, a lower portion of outer wall 50b, a lower wall 46, and two reinforcement walls 52. The reinforcing wall 52 is located in an interior space of tubular portion 38, at the same height as and below outer flange 42. The reinforcing wall 52 is positioned opposite a shock absorber 34, increasing strength of this area and suppressing reformation of the case side wall 28 in the event of a side collision, thereby limiting damage to the battery case.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a battery case for housing an in-vehicle battery, and particularly to the structure of the case side wall.

Background Art

[0002] Vehicles equipped with an electric motor as a driving prime mover are known, which are mounted with a battery for supplying power to the electric motor. In Patent Document 1 below, a bathtub-shaped tray (120) is arranged inside a square frame-shaped frame (110), and a battery case (battery case 100) in which a battery (battery 30) is housed in the recessed portion of the tray (120) is shown. Further, in paragraph 0087 of Patent Document 1 below, it is described that the frame (110) is formed of a steel plate roll forming material. Note that the member names and reference numerals in the above () are those used in Patent Document 1 below, and are not related to the member names and reference numerals used in the description of the embodiments of the present application.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] [[ID=3S]]The battery case is required to have sufficient strength to protect the housed battery during a vehicle collision.

[0005] An object of the present invention is to ensure the strength of a steel plate battery case during a vehicle collision.

Means for Solving the Problems

[0006] The battery case side wall of the vehicle battery of the present invention has a tubular portion with a closed cross-sectional structure formed by an upper wall, an inner wall, an outer wall and a lower wall; an inner flange positioned along the longitudinal direction of the tubular portion and erected on the inner wall; an outer flange positioned along the longitudinal direction of the tubular portion and erected between the upper and lower edges of the outer wall; and at least one reinforcing wall positioned within the internal space of the tubular portion at the same height as or below the outer flange, positioned along the longitudinal direction of the tubular portion, with its inner side in the vehicle width direction reaching the inner wall and its outer side in the vehicle width direction reaching the outer wall. The inner flange is sealed and joined to the lower cover of the battery case, and the outer flange is coupled to a load-receiving body, which is a structure that receives loads in a lateral collision and is located on the side of the battery case. The case side wall faces the load-receiving body in the portion below the outer flange. Furthermore, the case side wall, The case includes a first member made of a single steel plate that forms an inner flange, the portion of the inner wall from the upper edge to the upright portion of the inner flange, the upper wall, the portion of the outer wall above the outer flange, and the outer flange, and also includes a second member made of a single steel plate that forms a reinforcing wall. The case side wall has greater strength below the outer flange than above against lateral impact loads.

[0007] By adding reinforcing walls to increase the strength of the part of the case side wall that faces the load-bearing body, deformation during a lateral collision can be suppressed.

[0008] In the case side wall of the battery case described above, the second member may form multiple reinforcing walls, some of which overlap with the first member to form an outer flange together with the first member. Furthermore, the uppermost reinforcing wall may be at the same height as the outer flange.

[0009] By providing multiple reinforcing walls, the strength can be increased compared to having only one. Furthermore, by positioning the reinforcing walls at the same height as the outer flange, the strength near the point of load application from the outer flange can be reinforced.

[0010] In the case side wall of the battery case described above, the thickness of the second member may be greater than the thickness of the first member. This increases the strength of the reinforcing wall and the strength of the portion of the case side wall below the outer flange.

[0011] In the case side wall of the battery case described above, the second member may form a plurality of reinforcing walls, and the case side wall may further include a third member made of a single steel plate that forms the portion below the outer flange of the outer wall and partially overlaps with the first member to form the outer flange together with the first member.

[0012] By providing multiple reinforcing walls, the strength can be increased compared to when there is only one reinforcing wall. Furthermore, using three components increases the degree of freedom in shape and manufacturing method compared to using two components.

[0013] In the case side wall of the battery case described above, the plate thickness of the second and third members may be made thicker than the plate thickness of the first member. This increases the strength of the reinforcing wall and the strength of the portion of the case side wall below the outer flange. [Effects of the Invention]

[0014] In a battery case made of steel plate, by placing a reinforcing wall in the part of the case side wall facing the load-bearing body, the strength of this part can be increased, suppressing deformation of the case side wall against lateral impact loads and reducing damage to the battery case. [Brief explanation of the drawing]

[0015] [Figure 1] This diagram shows the schematic configuration of an electric vehicle equipped with a battery. [Figure 2] This diagram shows the general configuration of the battery pack, with the top cover removed to reveal the internal components. [Figure 3] This figure shows a cross-section of the case side wall and its surrounding structure. [Figure 4] This figure shows the manner in which the first and second members forming the side wall of the case are joined. [Figure 5] It is a diagram showing another configuration example of the case side wall. [Figure 6] It is a diagram showing yet another configuration example of the case side wall. [Figure 7] It is a diagram showing yet another configuration example of the case side wall. [Figure 8] It is a diagram showing yet another configuration example of the case side wall. [Figure 9] It is a diagram showing yet another configuration example of the case side wall.

Mode for Carrying Out the Invention

[0016] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, unless otherwise specified, terms indicating relative positions and directions such as front, rear, left, right, up, and down represent relative positions and directions related to the vehicle. Also, in the left-right direction (width direction) of the vehicle, the side closer to the center line extending in the front-rear direction of the vehicle is referred to as the inner side in the vehicle width direction, and the far side is referred to as the outer side in the vehicle width direction. In each figure, the direction of arrow FR is forward, the direction of arrow UP is upward, the direction of arrow LH is leftward, and the direction of arrow OUT is the outer side in the vehicle width direction.

[0017] FIG. 1 is a diagram showing a schematic configuration of the electric vehicle 10. The electric vehicle 10 may be a battery electric vehicle having only an electric motor as a prime mover for vehicle driving, or may be a hybrid electric vehicle having an electric motor and an engine as prime movers for vehicle driving. The electric vehicle 10 is equipped with a battery pack 16 that includes a battery for supplying power to the vehicle drive electric motor under the floor 14 of the passenger compartment 12.

[0018] FIG. 2 is a perspective view showing the schematic configuration of the battery pack 16 with its interior visible. The battery pack 16 includes a battery stack 18 in which battery cells are stacked, and a battery case 20 that houses the battery stack 18. In FIG. 2, only one battery stack 18 is shown. The battery case 20 includes a rectangular frame-shaped frame 22, an upper cover 24, and a lower cover 26 that are arranged so as to sandwich the frame 22 from above and below. The upper cover 24 and the lower cover 26 are sealingly joined to the frame 22 at their peripheries, and the battery case 20 is sealed. The frame 22, the upper cover 24, and the lower cover 26 define a space for housing the battery stack 18.

[0019] The frame 22 has left and right case side walls 28 that extend along the front-rear direction, and front and rear case end walls 30 that extend along the left-right direction. The front ends of the left and right case side walls 28 and both ends of the front case end wall 30 are joined, and the rear ends of the left and right case side walls 28 and both ends of the rear case end wall 30 are joined, forming a rectangular frame shape. Between the left and right case side walls 28, an inner cross member 32 that extends in the left-right direction and whose both ends are joined to the case side walls 28 is arranged. Also, the inner cross member 32 is joined to the lower cover 26 as well. In the illustrated battery pack 16, there are four inner cross members 32. The battery stack 18 is arranged between adjacent inner cross members 32, and between the rearmost inner cross member 32 and the rear case end wall 30, respectively. Therefore, the battery case 20 houses four battery stacks 18.

[0020] An impact absorber 34 is positioned on the outer side of the frame 22 in the vehicle width direction. The impact absorber 34 is connected to the case side wall 28 by fasteners such as bolts and nuts. The impact absorber 34 is a load-receiving body that receives the collision load from the side when the electric vehicle 10 collides sideways. Furthermore, the impact absorber 34 deforms under the load it receives to absorb collision energy and reduce the load applied to the battery pack 16. The impact absorber 34 is positioned extending along the longitudinal direction and has an outer shell portion with a closed cross-section that is roughly rectangular in cross-section perpendicular to the longitudinal direction, and at least one partition wall that divides the inner space of this outer shell in the left-right direction. The impact absorber 34 may be formed by extruding aluminum. The battery pack 16 is suspended and supported from the floor 14 via the impact absorber 34. The impact absorber 34 is fixed by bolts to rockers 36 (see Figure 3) located on the left and right side edges of the floor 14, and the battery pack 16 is fixed under the floor of the electric vehicle 10.

[0021] Figure 3 shows a cross-section of the battery pack 16 case side wall 28 and its surrounding structure perpendicular to the front-to-back direction. The case side wall 28 has a tubular portion 38 with a roughly rectangular closed cross-sectional structure, an inner flange 40 extending inward in the vehicle width direction from the tubular portion 38, and an outer flange 42 extending outward in the vehicle width direction from the tubular portion 38. The outer flange 42 is formed by overlapping two steel plate members, as will be described later. The tubular portion 38 has an upper wall 44 corresponding to the top edge of the rectangular cross-sectional shape, a lower wall 46 corresponding to the bottom edge, an inner wall 48 corresponding to the side edge on the inside in the vehicle width direction, and an outer wall 50 corresponding to the side edge on the outside in the vehicle width direction. The inner wall 48 directly faces the space that houses the battery stack 18, that is, the battery housing space 51 of the battery case 20.

[0022] A reinforcing wall 52 is positioned within the internal space enclosed by the tubular portion 38. The reinforcing wall 52 extends along the front-rear direction along the entire length of the case side wall 28. The reinforcing wall 52 may be positioned in a plane perpendicular to the vertical direction. The inner edge of the reinforcing wall 52 in the vehicle width direction reaches the inner wall 48, and the outer edge in the vehicle width direction reaches the outer wall 50. This battery case 20 has two reinforcing walls 52. The upper reinforcing wall 52A is positioned at the same height as the outer flange 42, which is made up of two overlapping steel plates, i.e., at the same position in the vertical direction. The lower reinforcing wall 52B is positioned approximately in the middle between the upper reinforcing wall 52A and the lower wall 46. There may be one reinforcing wall 52, or there may be three or more. The uppermost reinforcing wall 52 is positioned at the same height as the outer flange 42. In other words, no reinforcing walls are positioned higher than the outer flange 42.

[0023] The inner flange 40 is erected on the inner wall 48 and extends in the longitudinal direction of the vehicle along the entire length of the case side wall 28. The inner flange 40 may be located at the lower edge of the tubular portion 38. The outer flange 42 is erected on the outer wall 50 and extends in the longitudinal direction of the vehicle along the entire length of the case side wall 28. The outer flange 42 is located between the upper and lower edges of the outer wall 50.

[0024] The outer flange 42 is fastened to the upper surface of the shock absorber 34 by bolts 54 and nuts 56. The portion of the case side wall 28 below the outer flange 42 faces the shock absorber 34. A cylindrical collar 58 is further fixed to the shock absorber 34 by welding or other methods, and the shock absorber 34 is fixed to the lower surface of a rocker 36, which is one of the structural members of the vehicle body, by bolts 60 extending through the collar 58 and nuts (not shown). As a result, the battery pack 16 is suspended and supported by the vehicle body.

[0025] The lower cover 26 is joined to the inner flange 40 by welding, adhesive, or other methods, and the gap between the two is sealed. The upper cover 24 is joined to the case side wall 28, particularly to the upper wall 44 of the tubular portion 38. The upper cover 24 is joined to the upper wall 44 by rivets 62. Furthermore, the space between the upper cover 24 and the upper wall 44 is sealed by a sealing member 64 such as adhesive at the point inward in the vehicle width direction from the position where the upper cover 24 is joined by rivets 62. The sealing member 64 is arranged along the entire length of the case side wall 28.

[0026] An inner cross member 32 is coupled to the lower cover 26, and at its end, the inner cross member 32 is coupled to the inner wall 48 of the case side wall 28 via coupling brackets 65. The inner cross member 32 and coupling brackets 65, and the coupling brackets 65 and the inner wall 48 are coupled by welding, particularly arc welding. At least a portion of the inner cross member 32 is located below the outer flange 42. In the vertical direction, two reinforcing walls 52A and 52B are present in the area where the inner cross member 32 is located.

[0027] The case side wall 28 is formed from two members, a first member 66 and a second member 68, each made from roll-formed steel plate. The first member 66 and the second member 68 extend over the entire front-to-rear direction of the case side wall 28. The second member 68 may be divided into multiple parts in the front-to-rear direction. The first member 66 forms the inner flange 40, the inner wall 48, the upper wall 44, the portion of the outer wall 50 above the position where the outer flange 42 is erected, and the outer flange 42. The first member 66 is formed from a single steel plate by bending it through roll processing to form the shape shown. The second member 68 forms the outer flange 42, the portion of the outer wall 50 below the position where the outer flange 42 is erected, the lower wall 46, and two reinforcing walls 52A and 52B. The second member 68 is also formed from a single steel plate by bending it through roll processing to form the shape shown. Hereafter, the portion of the exterior wall 50 above the outer flange 42 will be referred to as the "upper portion of the exterior wall 50a," and the portion below it will be referred to as the "lower portion of the exterior wall 50b."

[0028] The second member 68 is joined to the first member 66 by overlapping a portion of it, and this overlapping portion together with the first member 66 forms the outer flange 42. Furthermore, the second member 68 is joined to the inner wall 48 by overlapping a portion of it in the portion between the portion forming the lower wall 46 and the portion forming the lower reinforcing wall 52B, and in the portion closer to the edge of the portion forming the upper reinforcing wall 52A. In addition, the second member 68 is joined to the portion between the portion forming the upper reinforcing wall 52A and the portion forming the lower reinforcing wall 52B by overlapping a portion that forms the lower outer wall portion 50b of itself.

[0029] By providing reinforcing walls 52 on the case side wall 28 at the same height as the outer flange 42 and below the outer flange 42, the strength of the portion of the case side wall 28 facing the impact absorber 34 is increased. As a result, the portion of the case side wall 28 below the outer flange 42 deforms less when subjected to the same load from the side compared to the portion above it. When a load from a lateral collision is applied to the case side wall 28 from the impact absorber 34, the collision load is received by the stronger portion, suppressing deformation of the case side wall 28. In addition, the reinforcing wall 52A being located at the same height as the outer flange 42 reinforces the area near where the load from the outer flange 42 is applied. Therefore, it helps to increase the strength of the case side wall 28 against lateral collision loads applied from the outer flange 42. Furthermore, the thickness of the second member 68 forming the case side wall 28 may be thicker than the thickness of the first member 66. This further increases the strength of the portion of the case side wall 28 facing the impact absorber 34. Furthermore, the load received on the case side wall 28 below the outer flange 42 is transmitted to the case end wall 30 and inner cross member 32, which are located away from the load input point in the front-rear direction, due to the high strength of this portion. Thus, the impact load is distributed and transmitted to the front and rear case end walls 30 and the four inner cross members 32. This suppresses the localized application of large loads to the battery case 20.

[0030] Figure 4 is a schematic diagram showing an example of how the first member 66 and the second member 68 that form the case side wall 28 are joined. The × marks in the figure indicate the location of spot welding, the shaded oval areas indicate areas joined with adhesive, and the diagonally shaded semicircular areas indicate the Precure sticker areas.

[0031] The first member 66 and the second member 68 are joined by spot welding at the portion forming the outer flange 42. The joints 70 and 72 between the inner wall 48 and the second member 68 are joined by adhesive and spot welding. In addition, the second member 68 is overlapped with itself at the lower part 50b of the outer wall and joined by adhesive and spot welding (joint 74). Furthermore, the inner flange 40 of the first member 66 and the lower cover 26 are joined by adhesive and spot welding. The adhesive is applied along the entire length of the inner flange 40. In addition, Precure Sealer 76 is applied along the edge of the inner flange 40 and along the edge of the lower cover 26, along the entire length of the inner flange 40, and is cured in a later heating process to seal the space between the inner flange 40 and the lower cover 26.

[0032] Figures 5 to 9 schematically show other embodiments of case side walls 128, 228, 328, 428, and 528. In each figure, the × marks indicate the location of spot welding, and the shaded oval areas indicate areas joined by adhesive. Furthermore, the semicircular areas with double diagonal lines indicate areas that are arc-welded, and the circular areas with double diagonal lines indicate areas that are seam-welded. The relationship between each case side wall and the surrounding configuration is the same as that of the case side wall 28 described above.

[0033] The case side wall 128 shown in Figure 5 is formed from three members. The three members, the first member 166, the second member 168, and the third member 180, are all formed by roll forming a single steel plate. The first member 166 is the same as the first member 66 of the case side wall 28 described above. The second member 168 forms three reinforcing walls 152. The three reinforcing walls 152 may be arranged in a plane perpendicular to the vertical direction. When distinguishing the three reinforcing walls 152, they are referred to as reinforcing wall 152A, reinforcing wall 152B, and reinforcing wall 152C from top to bottom. In the second member 168, reinforcing wall 152A is continuous with the portion forming the outer flange 42, and these form a single plane. The third member 180 forms the lower outer wall portion 50b and the lower wall 46.

[0034] The second member 168 is joined to the third member 180 by arc welding at the lower wall 46. Furthermore, a portion of the second member 168 and a portion of the third member 180 overlap with the portion of the first member 166 that forms the outer flange 42, and together with the first member 166, they form the outer flange 42. The second member 168 is joined to the portion of the first member 166 that forms the inner wall 48 by seam welding between the reinforcing wall 152A and the reinforcing wall 152B, and between the reinforcing wall 152C and the lower wall 46. Furthermore, the second member 168 is joined by adhesive to the portion of the third member 180 that forms the lower outer wall portion 50b between the reinforcing wall 152B and the reinforcing wall 152C.

[0035] By providing reinforcing walls 152 on the case side wall 128 at the same height as the outer flange 42 and below the outer flange 42, the strength of the portion of the case side wall 128 facing the impact absorber 34 is increased. When a load due to a lateral collision is applied to the case side wall 128 from the impact absorber 34, the collision load is received by the stronger portion, suppressing deformation of the case side wall 128. The uppermost reinforcing wall 152A of the second member 168 is continuous with the portion forming the outer flange 42 and forms the same plane. The load applied from the outer flange 42 is transmitted through the member that forms the same plane as the outer flange 42, allowing the load to be efficiently transmitted to the reinforcing wall 152A. As a result, the area near the load application point from the outer flange 42 is reinforced. Furthermore, by providing three reinforcing walls 152, the strength of the case side wall 128 can be increased compared to the case with two reinforcing walls. The thickness of the second member 168 and the third member 180 may be greater than that of the first member 166. This further increases the strength of the portion of the case side wall 128 that faces the shock absorber 34.

[0036] The case side wall 228 shown in Figure 6 is formed from three members. The three members, the first member 266, the second member 268, and the third member 280, are all formed by roll forming a single steel plate. The first member 266 is the same as the first member 66 of the case side wall 28 described above. The second member 268 forms two reinforcing walls 252. The two reinforcing walls 252 may be arranged in a plane perpendicular to the vertical direction. When distinguishing between the two reinforcing walls 252, the one located above is referred to as reinforcing wall 252A, and the one located below is referred to as reinforcing wall 252B. Reinforcing wall 252A is located at the same height as the outer flange 42. The second member 268 further forms a lower wall 46. The third member 280 forms the lower outer wall portion 50b and the outer flange 42. The outer flange 42 is formed by overlapping a part of the first member 266 and a part of the third member 280.

[0037] The third member 280 is joined to the second member 268 by arc welding at the lower wall 46. The second member 268 is joined to the portion of the first member 266 that forms the inner wall 48 by adhesive at the edge side of the reinforcing wall 252A. The second member 268 is also joined to the portion of the first member 266 that forms the inner wall 48 between the reinforcing wall 252B and the lower wall 46 by adhesive and spot welding. Furthermore, the second member 268 is joined to the portion of the third member 280 that forms the lower outer wall portion 50b between the reinforcing wall 252A and the reinforcing wall 252B by adhesive.

[0038] By providing reinforcing walls 252 on the case side wall 228 at the same height as the outer flange 42 and below the outer flange 42, the strength of the portion of the case side wall 228 facing the impact absorber 34 is increased. When a load due to a lateral collision is applied to the case side wall 228 from the impact absorber 34, the collision load is received by the stronger portion, suppressing deformation of the case side wall 228. The uppermost reinforcing wall 252A of the second member 268 is located at the same height as the portion forming the outer flange 42. This reinforces the area near the point where the load from the outer flange 42 is applied. The plate thickness of the second member 268 and the third member 280 may be thicker than that of the first member 266. This further increases the strength of the portion of the case side wall 228 facing the impact absorber 34.

[0039] The case side wall 328 shown in Figure 7 is the same as the case side wall 28 shown in Figure 4, but with the dimensions in the vehicle width direction differing above and below the outer flange 42. Both the first member 366 and the second member 368 are formed by roll forming a single steel plate. The first member 366 is the same as the first member 66 of the case side wall 28 described above. The second member 368 is the same as the second member 68 described above, but with the portion forming the outer flange 42 extended inward in the vehicle width direction, and the portion forming the reinforcing wall 352 and the lower wall 46 shortened accordingly. The case side wall 328 is advantageous when it is desired to increase the distance from the impact absorber 34, or when an impact absorber 34 with large dimensions in the vehicle width direction is used.

[0040] The case side wall 428 shown in Figure 8 is formed from three members. The three members, the first member 466, the second member 468, and the third member 480, are all formed by roll forming a single steel plate. The first member 466 is the same as the first member 66 of the case side wall 28 described above. The second member 468 forms two reinforcing walls 452, a lower wall 46, and a part of the lower portion 50b of the outer wall. The two reinforcing walls 452 may be arranged in a plane perpendicular to the vertical direction. When distinguishing between the two reinforcing walls 452, the one located above is referred to as reinforcing wall 452A, and the one located below is referred to as reinforcing wall 452B. In the second member 468, reinforcing wall 452A is continuous with the portion that forms the outer flange 42, and these form a single plane. The third member 480 forms the lower portion 50b of the outer wall.

[0041] The second member 468 is joined to the first member 466 by arc welding at the lower edge of the portion of the first member 466 that forms the inner wall 48. The second member 468 is also joined to the portion of the first member 446 that forms the inner wall 48 by adhesive in the portion between the two reinforcing walls 452A and 452B. The third member 480 is joined to the second member 468 by arc welding at the lower wall 46, and to the second member 468 at the lower portion of the outer wall 50b by adhesive and spot welding. Furthermore, a portion of the second member 468 and a portion of the third member 480 overlap with the portion of the first member 466 that forms the outer flange 42, and together with the first member 466, they form the outer flange 42.

[0042] By providing reinforcing walls 452 on the case side wall 428 at the same height as the outer flange 42 and below the outer flange 42, the strength of the portion of the case side wall 428 facing the impact absorber 34 is increased. When a load due to a lateral collision is applied to the case side wall 428 from the impact absorber 34, the collision load is received by the stronger portion, suppressing deformation of the case side wall 428. The reinforcing wall 452A located above the second member 468 is continuous with the portion forming the outer flange 42 and forms the same plane. The load applied from the outer flange 42 is transmitted through the member that forms the same plane as the outer flange 42, allowing the load to be efficiently transmitted to the reinforcing wall 452A. As a result, the area near the load application point from the outer flange 42 is reinforced. The plate thickness of the second member 468 and the third member 480 may be thicker than that of the first member 466. This further increases the strength of the portion of the case side wall 428 facing the impact absorber 34.

[0043] The case side wall 528 shown in Figure 9 is formed from three members. The three members, the first member 566, the second member 568, and the third member 580, are all formed by roll forming a single steel plate. The first member 566 is the same as the first member 66 of the case side wall 28 described above. The second member 568 forms a reinforcing wall 552 and a lower wall 46. The reinforcing wall 552 may be arranged in a plane perpendicular to the vertical direction. In the second member 568, the reinforcing wall 552 is continuous with the portion that forms the outer flange 42, and these form a single plane. The third member 580 forms the lower outer wall portion 50b.

[0044] The second member 568 is positioned so that the portion between the reinforcing wall 552 and the lower wall 46 is aligned with the inner wall 48, and in this portion it is joined to the first member 566 by adhesive and spot welding. The third member 580 is joined to the second member 568 at the lower wall 46 by arc welding. Furthermore, a portion of the second member 568 and a portion of the third member 580 overlap with the first member 566 to form an outer flange 42. The plate thickness of the second member 568 and the third member 580 is greater than the plate thickness of the first member 566. Furthermore, the plate thickness of the second member 568 may be greater than the plate thickness of the third member 580.

[0045] By making the thickness of the second member 568 greater than that of the first member 566, and by providing a reinforcing wall 552 on the case side wall 528 at the same height as the outer flange 42, the strength of the portion of the case side wall 528 facing the impact absorber 34 is increased. When a load due to a lateral collision is applied to the case side wall 528 from the impact absorber 34, the collision load is received by the stronger portion, suppressing deformation of the case side wall 528. The reinforcing wall 552 of the second member 568 is continuous with the portion forming the outer flange 42 and forms the same plane. The load applied from the outer flange 42 is transmitted through the member that forms the same plane as the outer flange 42, allowing the load to be efficiently transmitted to the reinforcing wall 552. As a result, the area near the load application point from the outer flange 42 is reinforced. This helps to increase the strength of the case side wall 528 against lateral collision loads applied from the outer flange 42.

[0046] When the outer flange 42 is formed by overlapping two steel plate members, the member forming the upper part 50a of the outer wall and the member forming the lower part 50b of the outer wall are overlapped. When the outer flange 42 is formed by overlapping three steel plate members, in addition to the member forming the upper part 50a of the outer wall and the member forming the lower part 50b of the outer wall, a member forming a reinforcing wall located at the same height as the outer flange 42 is overlapped. [Explanation of symbols]

[0047] 10 electric vehicles, 14 floors, 16 battery packs, 20 battery cases, 22 frames 24 Upper cover, 26 Lower cover, 28, 128, 228, 328, 428, 528 Case side walls, 30 Case end walls, 32 Inner cross member, 34 Impact absorber (load-bearing body), 38 Tubular section, 40 Inner flange, 42 Outer flange, 44 Upper wall, 46 Lower wall, 48 Inner wall, 50 Outer wall, 50a Upper part of outer wall, 50b Lower part of outer wall, 52, 152, 252, 352, 452, 552 Reinforcement walls, 66, 166, 266, 366, 466, 566 First members, 68, 168, 268, 368, 468, 568 Second members, 180, 280, 480, 580 Third members.

Claims

1. The side wall of the battery case of a vehicle battery, A tubular portion of a closed cross-sectional structure formed by an upper wall, an inner wall, an outer wall, and a lower wall, An inner flange positioned along the longitudinal direction of the tubular portion and erected on the inner wall, the inner flange being sealed and joined to the lower cover of the battery case, An outer flange positioned along the longitudinal direction of the tubular portion and erected between the upper and lower edges of the outer wall, the outer flange is connected to a load-receiving body which is a structure that receives loads in a lateral collision located to the side of the battery case, Within the internal space of the tubular portion, at the same height as or below the outer flange, is at least one reinforcing wall positioned along the longitudinal direction of the tubular portion, with its inner side in the vehicle width direction reaching the inner wall and its outer side in the vehicle width direction reaching the outer wall, It has, The side wall of the case faces the load-bearing body in the portion below the outer flange, The side wall of the case is A first member consisting of a single steel plate forming an inner flange, the portion of the inner wall from its upper edge to the vertical portion of the inner flange, the upper wall, the portion of the outer wall above the outer flange, and the outer flange, A second member consisting of a single steel plate that forms the reinforcing wall, Includes, In this case, the side wall has greater strength below the outer flange than above the outer flange when subjected to lateral impact loads. The side wall of the battery case.

2. The case side wall of the battery case according to claim 1, The second member forms a plurality of reinforcing walls, and a portion of it overlaps with the first member, and together with the first member, forms the outer flange. The uppermost reinforcing wall is at the same height as the outer flange. The side wall of the battery case.

3. A case side wall for a battery case according to claim 1 or 2, wherein the thickness of the second member is greater than the thickness of the first member.

4. The case side wall of the battery case according to claim 1, The second member forms a plurality of the reinforcing walls, The case side wall further includes a third member made of a single steel plate that forms the portion of the outer wall below the outer flange and partially overlaps with the first member to form the outer flange together with the first member. The side wall of the battery case.

5. A case side wall of a battery case according to claim 4, wherein the thickness of the second member and the third member is greater than the thickness of the first member.

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