Battery case

Abstract

To provide structure capable of resolving insufficient strength of a first floor part of an inner wall in a battery case including a side frame molded by roll molding.SOLUTION: A semi-finished frame 21 having a cross section with a single stroke shape as shown in Fig. 3(a) is obtained by roll molding a single metal plate. The semi-finished frame 21 is welded to obtain a side frame 20 shown in Fig. 3(b). In the side frame 20, a first floor part of an inner wall 27 and an inner wall part 34 are joined with a second weld metal 38 to form double-wall structure, doubling a strength of this portion.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a battery case that houses a drive battery. [Background technology]

[0002] [Terminology explanation] In the following description, "inner side" or "inside" refers to the center side of the vehicle width relative to the vehicle, and "outer side" or "outside" refers to the side away from the center of the vehicle width. Additionally, the longitudinal direction refers to the front-to-rear direction of the vehicle, and the longitudinal axis refers to an axis extending in the longitudinal direction. Moreover, the radius of curvature is the reciprocal of the curvature and is the same as the radius.

[0003] [Prior Art] In so-called electric vehicles, a large number of drive batteries (hereinafter, abbreviated as batteries) are arranged under the floor. The large number of batteries are generally provided in the vehicle in a state of being housed in a battery case.

[0004] 2. Description of the Related Art Conventionally, battery cases of various structures have been known (see, for example, Patent Document 1 (FIGS. 3 and 4)).

[0005] The technique disclosed in Patent Document 1 will be described with reference to FIGS. 12(a) and 12(b) and 13(a) and 13(b). As shown in FIG. 12(a), the battery case 100 has, as its main elements, side frames 101 extending in the longitudinal direction and a cross member 102 extending in the vehicle width direction. The side frame 101 is formed by bending a single metal plate using a plastic processing method such as roll forming. The side frame 101 is joined to the cross member 102 by welding.

[0006] FIG. 12(b) is a view taken along the arrow b in FIG. 12(a). As shown in FIG. 12( b ), the side frame 101 that has been plastically processed inevitably has arcuate portions 104 at the corner portions 103 . The smaller the radius of curvature R of the arc portion 104, the more likely it is that cracks will occur during plastic processing. In order to prevent cracks, advanced processing techniques are required. The larger the curvature radius R of the arc portion 104, the easier the plastic working becomes.

[0007] However, if the radius of curvature R is large, the approximately triangular gap 105 existing outside the arc portion 104 becomes large. When the cross member 102 is joined to the side frame 101 by welding, the weld bead 106 cannot be provided in the gap 105. The length of the weld bead 106 is shortened by the amount of the gap 105, and the joining strength is reduced.

[0008] Also, the lower part of gap 105 is V-shaped. Battery case 100 is mounted on a vehicle body. The vehicle body vibrates due to unevenness in the road surface. An external force is applied to battery case 100 due to this vibration, causing it to elastically deform. During elastic deformation, the V-shape at the bottom of the gap 105 becomes the starting point of a crack. This starting point is undesirable because it can lead to cracking and rupture of the weld bead 106.

[0009] Next, a description will be given with reference to FIGS. As shown in Figure 13(a), the side frame 101 consists of a flange portion 108 extending horizontally to receive a bottom plate, an inner wall first floor portion 109 extending upward from the flange portion 108, an inner wall second floor portion 111 extending upward from the inner wall first floor portion 109, an upper plate portion 112 extending horizontally outward from the upper end of the inner wall second floor portion 111, an outer wall second floor portion 113 extending downward from the tip of the upper plate portion 112, a partition plate portion 114 extending horizontally from the outer wall second floor portion 113 to reach the inner wall first floor portion 109, a lower plate portion 115 extending horizontally outward from the flange portion 108, and an outer wall first floor portion 116 extending upward from the tip of the lower plate portion 115 to reach the partition plate portion 114.

[0010] A downward force caused by the weight of the battery is applied to the flange portion 108. This downward force is first applied to the first floor portion 109 of the inner wall. If the bending rigidity of the first floor portion 109 of the inner wall is small, the deformation becomes large, which affects the overall shape of the side frame 101.

[0011] In Fig. 13(a), depending on the shape of the battery to be stored, it may be necessary to increase the height of the side frame 101. One method for meeting this requirement is to vertically extend the inner wall first floor portion 109 and the outer wall first floor portion 116. As a result, Fig. 13(b) is obtained.

[0012] In the side frame 101 of the form shown in FIG. 13(b), if the bending rigidity of the first floor portion 109 of the inner wall is small, the deformation becomes increasingly large, which has a significant effect on the overall shape of the side frame 101. In addition, in the embodiment of FIG. 13(b), the rolls and rolling equipment required for roll forming become large, resulting in increased manufacturing costs.

[0013] As described above, the conventional technology has problems with strength deficiencies due to the arcuate portion and strength deficiencies in the inner wall first floor portion 109. A structure that can resolve these strength deficiencies is required. Describe the assignment. [Prior art documents] [Patent documents]

[0014] [Patent Document 1] China Utility Model No. 212529286 Summary of the Invention [Problem to be solved by the invention]

[0015] The present invention aims to provide a structure that facilitates the manufacture of a battery case using a battery case that includes a roll-formed side frame and a press-formed or cast cross member that is joined to the side frame by welding, and that can eliminate the lack of strength caused by the arc portion and the lack of strength of the inner wall portion. [Means for solving the problem]

[0016] The invention according to claim 1 is a battery case comprising a bottom plate that supports a battery and a frame that surrounds the battery placed on the bottom plate, The frame body is made up of left and right side frames and cross members extending between the front and rear ends of the side frames, The side frame is formed by plastic working a single metal plate to form a closed cross section, and the closed cross section has at least an arc portion between an upper plate portion and an upper end of an inner wall portion, The cross member is characterized by having a tongue that extends beyond the arc portion and is joined to the upper plate portion.

[0017] The invention according to claim 2 is the battery case according to claim 1, The side frame is composed of a flange portion supporting the bottom plate, an extension portion extending upward from the flange portion, an inner wall first floor portion extending upward from the extension portion, an inner wall second floor portion as the inner wall portion extending upward from the inner wall first floor portion, an upper plate portion extending horizontally outward from the upper end of the inner wall second floor portion via an arc portion, an outer wall portion extending downward from the tip of the upper plate portion, a lower plate portion extending horizontally from the lower end of the outer wall portion toward the inner wall first floor portion, an inner wall portion extending upward from the tip of the lower plate portion while following the inner wall first floor portion, and a partition plate portion extending horizontally from the upper end of the inner wall portion to the outer wall portion, and the inner wall first floor portion and the inner wall portion form a double wall structure, The extension portion and the flange portion form an L-shaped cross section.

[0018] The invention according to claim 3 is the battery case according to claim 1, The cross member is a first member having the same shape as a light Z-shaped steel, the first member includes a first floor portion extending horizontally toward the inside of the battery case, a first wall portion extending upward from the first floor portion, and a first ceiling portion extending horizontally from an upper end of the first wall portion in a direction opposite to the first wall portion, The first wall portion is provided with a connection piece that is joined to the inner wall portion of the side frame.

[0019] The invention according to claim 4 is the battery case according to claim 3, A second member having the same shape as the light Z-shaped steel is fitted and joined to the first member, the second member being made up of a second floor portion extending horizontally so that the first floor portion can be placed on it, a second wall portion extending upward from the second floor portion, and a second ceiling portion extending horizontally so that the first ceiling portion can be placed on it, the second wall portion being spaced a predetermined distance from the first wall portion along the longitudinal axis of the side frame, The present invention is characterized in that the two components are joined with the second floor portion placed on the flange portion, or the two components are joined with the flange portion placed on the first floor portion.

[0020] The invention according to claim 5 is the battery case according to claim 4, The present invention is characterized in that an intermediate plate is disposed between the first wall portion and the second wall portion at the same height as the partition plate portion.

[0021] The invention according to claim 6 is the battery case according to claim 3, At least one of the first wall portion and the second wall portion has an end extension portion extending along the arc portion.

[0022] The invention according to claim 7 is the battery case according to claim 1, The outer wall portion has a horizontal groove for receiving a tip end of the partition plate portion.

[0023] The invention according to claim 8 is the battery case according to claim 1, The present invention is characterized in that a first shock absorbing member is arranged in the first floor space below the partition board portion, and a second shock absorbing member is arranged in the second floor space above the partition board portion.

[0024] The invention according to claim 9 is the battery case according to claim 1, The side frame has an open end which is closed by a cover member, and an extension piece which extends to and is joined to the cross member is integrally formed with the cover member.

[0025] The invention according to claim 10 is the battery case according to claim 3, a vehicle body mounting member is attached to the outer wall portion, a cooling plate is disposed under the bottom plate, and a protection plate is disposed under the cooling plate; The protective plate is characterized in that it is fixed to the vehicle body mounting member and the second floor portion. Effect of the Invention

[0026] In the invention according to claim 1, the side frame is a roll-formed product made of a single metal plate, which means that the side frame can be easily manufactured by a roll forming method.

[0027] In addition, because the cross member is formed by press molding or casting, the tongue portion that protrudes in part can be easily formed. This tongue portion extends beyond the arc portion and is joined to the upper plate portion of the side frame, so the joining strength between the side frame and the cross member is increased despite the existence of the arc portion. Therefore, according to the present invention, in a battery case including a roll-formed side frame and a press-formed cross member joined to the side frame by welding, a structure is provided that can eliminate the lack of strength caused by the arc portion and the lack of strength of the inner wall portion, which is simple and easy to manufacture at low cost.

[0028] In the invention according to claim 2, the first floor inner wall of the side frame and the inner wall are of double wall structure, so the bending strength of this part is doubled and the lack of strength in the first floor inner wall is eliminated. In addition, the extension part and the flange part form an L-shaped cross section. Since it is an L-shaped cross section, the extension part is reinforced by the flange part. Since it is reinforced by the flange part, the extension part is allowed to extend downward. By extending the extension portion downward, the height of the side frame can be easily increased. In addition, since it is only necessary to extend the extension portion, it is not necessary to enlarge the rolls and rolling equipment for roll forming, and the manufacturing cost is not increased.

[0029] In the invention according to claim 3, the first member, which is the main element of the cross member, is made to have the same shape as the light Z-shaped steel, so the first member can be easily and inexpensively manufactured by press forming or casting, just like the light shaped steel. The partially protruding tongue piece can also be easily formed by press forming or casting.

[0030] In the invention according to claim 4, in addition, since the second wall portion is spaced a predetermined distance from the first wall portion, a closed cross section is formed, and the strength of the cross member is increased. Furthermore, since the first wall portion and the second wall portion are flat plates, the connection pieces can be easily formed integrally therewith. Furthermore, by joining the flange portion on the side frame to the first or second floor portion on the cross member, the joining strength between the side frame and the cross member can be increased. In particular, the joining strength at the inner corners of the frame is increased, which can increase the strength of the frame. In addition, since the flange portion and the first floor portion (or the second floor portion) are connected, the supporting rigidity of the bottom plate is increased.

[0031] In the invention according to claim 5, since the intermediate plate is disposed between the first wall portion and the second wall portion in the cross member, the strength of the cross member is increased. In addition, since the partition plate portion on the side frame side and the intermediate plate on the cross member side are the same height, the horizontal force applied to the partition plate portion is smoothly transmitted to the intermediate plate, and the horizontal force applied to the intermediate plate is smoothly transmitted to the partition plate portion, increasing the supporting rigidity of the frame body.

[0032] In the invention according to claim 6, at least one of the first wall and the second wall on the cross member side is provided with an end extension extending along the arc portion on the side frame side. The end extension can be welded to the arc portion, which can further increase the joint strength between the side frame and the cross member. In particular, the joint strength at the corners of the frame is increased, which can further increase the strength of the frame. The sealing of the battery storage section is also improved.

[0033] In the invention according to claim 7, a horizontal groove is provided on the inner surface side of the outer wall portion, and the tip of the partition plate portion is accommodated in this horizontal groove. If there was no horizontal groove and the tip of the partition plate was placed against the exterior wall, the partition plate would not be visible from outside the exterior wall, and welding the tip of the partition plate to the exterior wall would be difficult. In contrast, in the present invention, since the tip of the partition plate is fitted into the horizontal groove, the position of the horizontal groove is determined from the outside of the outer wall portion, so that a laser beam or the like can be fired toward the outer surface of the horizontal groove, making welding easy.

[0034] In the invention according to claim 8, a first shock absorbing member is disposed in the first floor space of the side frame, and a second shock absorbing member is disposed in the second floor space. Since the side impact load applied to the side frame is a nearly horizontal force, it is absorbed mainly by the plastic deformation of the partition plate. At this time, the second shock absorbing member and the first shock absorbing member disposed above and below the partition plate also plastically deform to absorb the side impact load. That is, the second impact absorbing member and the first impact absorbing member cooperate with the partition plate portion to reliably absorb the side impact load.

[0035] In the invention according to claim 9, the side frame has open ends, but these ends are covered with lid members. If the ends are open, there is a concern that foreign matter may get into the inside of the side frame, but since they are covered with lids, there is no need to worry about this. In addition, if the ends are open, the rigidity of the side frame decreases, but by covering them with a lid, the rigidity can be increased. Furthermore, by providing an extension piece for the cover member and joining this extension piece to the cross member, the joining strength between the cross member and the side frame can be increased.

[0036] According to the invention as defined in claim 10, the cooling plate and the protection plate for protecting the cooling plate can be attached reliably and easily to the bottom of the battery case. [Brief description of the drawings]

[0037] [Figure 1] FIG. 2 is an exploded perspective view of the battery case according to the present invention. [Diagram 2] 2 is a cross-sectional view taken along line 2-2 of FIG. 1. [Diagram 3] 1A is a cross-sectional view of the side frame after plastic working (before welding), and FIG. 1B is a cross-sectional view of the side frame after welding. [Figure 4] 4 is a cross-sectional view taken along line 4-4 of FIG. 1. [Diagram 5] FIG. [Figure 6] (a) is a rear view of the corner of the frame, and (b) is an enlarged view of part b in (a). [Figure 7] 1A is another exploded perspective view of the corner of the frame body, FIG. 1B is a perspective view of the corner of the frame body, FIG. 1C is a view taken along the arrow c in FIG. 1B, and FIG. [Figure 8] 13(a) and 13(b) are diagrams explaining an intermediate plate to be added to a cross member. [Figure 9] 13(a) to 13(d) are diagrams illustrating horizontal grooves. [Figure 10] FIG. 3 is a layout diagram of the first and second shock absorbing members. [Figure 11] 13(a) and 13(b) are diagrams illustrating a rear fastening member. [Figure 12] 1A is a perspective view of a conventional side frame and cross member, and FIG. 1B is a view taken from the direction of arrow b in FIG. [Figure 13] (a) is a front view of a conventional side frame, and (b) is a modified version of (a). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0038] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will now be described with reference to the accompanying drawings. In the attached drawings, the directions (front / rear, left / right, up / down) are defined based on the driver driving the vehicle, assuming that the battery case of the present invention is mounted on the vehicle. The vehicle width direction is defined as the left / right of the direction indicator, and the vehicle length direction is defined as the front / rear of the direction indicator. EXAMPLES

[0039] [Battery case] As shown in FIG. 1, the battery case 10 includes a bottom plate 12 that supports a battery 11, and a frame 13 that surrounds the battery 11 placed on the bottom plate 12. Preferably, the battery case 10 includes a top cover 14 that is placed on the frame 13 so as to cover the battery 11 .

[0040] More preferably, a protective plate 16 is attached under the bottom plate 12. The top cover 14 and the protective plate 16 are detachably attached to the frame 13, but the bottom plate 12 is joined to the frame 13 by welding (or with an adhesive).

[0041] The bottom plate 12 is a flat plate. The flat plate may be a completely flat plate or a plate that locally includes small irregularities of about 10 mm or less (i.e., a nearly flat plate), and in short, it is sufficient that the plate is macroscopically flat.

[0042] The frame 13 is made up of left and right side frames 20 and cross members 40 extending across the front and rear ends of the left and right side frames 20. In the embodiment, the width narrows toward the front, but it may be a square or rectangle.

[0043] Preferably, a plurality of sub-members 42 are stretched across the left and right side frames 20 to reinforce the frame body 13. Preferably, the vehicle body mounting member 43 having an L-shaped cross section is attached from the outside to each of the left and right side frames 20. Note that the vehicle body mounting member 43 having an L-shaped cross section may be roll-formed to be integrated with each of the side frames 20.

[0044] Preferably, a rear fastener 44 is connected to the rear end of the side frame 20 . This rear fastening member 44 is called the rear fastening member 44 because it is a member that is disposed at the rear and is used when fastening the battery case 10 to the inside of the side sill of the vehicle body with a bolt or the like. As will be described in more detail below, the rear fastening member 44 is a multi-purpose member that serves to close the rear opening of the side frame 20 as well as other purposes.

[0045] Each of the components described above with reference to FIG. 1 will now be described in detail.

[0046] FIG. 2 is a cross-sectional view taken along line 2-2 of FIG. As shown in Figure 2, a vehicle body mounting member 43 is attached to the outside of a side frame 20 having a sun-shaped cross-section, a bottom plate 12 is placed on the flange portion 25 on the side frame 20 side, a cooling plate 17 is placed below this bottom plate 12, and a protective plate 16 for protecting this cooling plate 17 is attached to the vehicle body mounting member 43 from below and fixed with fasteners 18 such as screws.

[0047] [Side frame] FIG. 3(a) is a cross-sectional view of a semi-finished frame 21 after roll forming and before welding. A metal plate called a blank is subjected to plastic working by roll forming to obtain a semi-finished frame 21 having a cross section in a unicursal shape. The blank may be any of an aluminum alloy, a steel plate, and a tailored blank.

[0048] The semi-finished frame 21 is compressed from the left and right to overlap the plates. Next, the overlapping portions are welded. The welding method is preferably MIG welding, TIG welding, or laser beam welding, but flanges and holes may be added and spot welding or other welding methods may be used. As shown in FIG. 3(b), for example, a laser beam 23 is emitted from a laser torch 22 to perform welding.

[0049] As shown in Figure 3(b), the completed side frame 20 consists of a flange portion 25 supporting the bottom plate (Figure 2, symbol 12), an extension portion 26 extending upward from this flange portion 25, an inner wall first floor portion 27 extending upward from this extension portion 26, an inner wall second floor portion 28 as an inner wall portion extending upward from the inner wall first floor portion 27, an upper plate portion 31 extending horizontally outward from the upper end of the inner wall second floor portion 28 via an arc portion 29, an outer wall portion 32 extending downward from the tip of the upper plate portion 31, a lower plate portion 33 extending horizontally from the lower end of the outer wall portion 32 toward the inner wall first floor portion 27, an inner wall portion 34 extending upward from the tip of the lower plate portion 33 along the inner wall first floor portion 27, and a partition plate portion 35 extending horizontally from the upper end of the inner wall portion 34 to the outer wall portion 32.

[0050] The tip of the partition plate portion 35 is joined to the outer wall portion 32 by a first weld metal 37. In addition, the inner wall first floor portion 27 and the interior wall portion 34 are joined by a second weld metal 38, so that the inner wall first floor portion 27 and the interior wall portion 34 form a double-wall structure.

[0051] The second weld metal 38 is preferably formed at two points, one above and one below, in a cross-sectional view. With two points, the interior wall portion 34 is efficiently joined to the interior wall first floor portion 27. However, the second weld metal 38 may be formed at three or more points or even at one point. As with the first weld metal 37, it is fixed from the outside by laser welding, riveting, adhesive, or the like.

[0052] A downward force due to the weight of the battery is applied to the flange portion 25, but since the double-wall structure portion has high bending rigidity, the side frame 20 can adequately withstand the large downward force. That is, since the inner wall first floor portion 27 of the side frame 20 and the inner wall portion 34 have a double wall structure, the bending strength of this portion is doubled, and the lack of strength in the inner wall first floor portion 27 is eliminated. In addition, the side frame 20 is formed from a single metal plate by plastic forming. The side frame 20 can be easily manufactured by roll forming.

[0053] Furthermore, the extension portion 26 and the flange portion 25 form an L-shaped cross section. If there were no flange portion 25, extension portion 26 would bend easily when subjected to an external force. If there is flange portion 25, extension portion 26 is less likely to bend even when subjected to an external force. In other words, because of its L-shaped cross section, extension portion 26 is reinforced by flange portion 25. Because extension portion 26 is reinforced by flange portion 25, it is permitted for it to extend downward.

[0054] By extending the extension portion 26 downward, the height of the side frame 20 can be easily increased. In addition, since the extension portion 26 is merely extended, it is not necessary to enlarge the rolls and rolling equipment for roll forming, and the manufacturing cost is not increased.

[0055] [Cross member] FIG. 4 is a cross-sectional view taken along line 4-4 in FIG. As shown in Fig. 4, the cross member 40 is a member in which a first member 45 having the same shape as a light Z-shaped steel defined in JIS G 3350 is joined to a second member 51 having the same shape as the light Z-shaped steel by a deposited metal 49 or the like. It is a press-formed product of an aluminum alloy plate or a steel plate. Also, the second member 51 can be omitted by forming the first member 45 by casting.

[0056] The first member 45 consists of a first floor portion 46 extending horizontally toward the inside of the battery case (Figure 1, symbol 10), a first wall portion 47 extending upward from this first floor portion 46, and a first ceiling portion 48 extending horizontally from the upper end of this first wall portion 47 in the opposite direction to the first wall portion 47.

[0057] The second member 51 is composed of a second floor 52 extending horizontally so that the first floor 46 can be placed on it, a second wall 53 extending upward from the second floor 52, and a second ceiling 54 extending horizontally so that the first ceiling 48 can be placed on it. Preferably, between the second floor 52 and the second wall 53, there is interposed a bottom 55 extending horizontally from the lower end of the second wall 53, and an inclined portion 56 rising obliquely from the tip of the bottom 55 to the second floor 52.

[0058] By providing the bottom portion 55 and the inclined portion 56, a storage space for the cooling plate 17 can be secured, and also a mounting seat for the protection plate 16 can be secured. 4 and 2, the cooling plate 17 and the protection plate 16 for protecting the cooling plate 17 can be attached to the bottom of the battery case 10 reliably and easily.

[0059] 4, the second wall portion 53 is spaced a predetermined distance W from the first wall portion 47 to increase the bending rigidity of the cross member 40. In the case of a casting, this can be achieved by increasing the thickness or adding ribs.

[0060] [Tongue and connector] 5, the cross member 40 is provided with a tongue piece 58. More specifically, the tongue piece 58 extends from the first ceiling portion 48. Preferably, the first wall portion 47 and / or the second wall portion 53 is provided with a connection piece 59. The connection piece 59 is joined to the first floor portion 27 of the inner wall of the side frame 20.

[0061] FIG. 6(b) is an enlarged view of part b in FIG. 6(a). 6(b), the tongue piece 58 extends beyond the arc portion 29 and is joined to the upper plate portion 31 by the weld metal 49. A roughly triangular gap 61 inevitably exists outside the arc portion 29. This shortens the length of the weld bead 62. The joint strength decreases by the amount of the shortened length. This reduction can be covered by the connection with the tongue piece 58 .

[0062] 6(a), the connection piece 59 is joined to the inner wall first floor portion 27, which is a main part of the double wall structure, with a deposited metal 49. This joining reinforces the joining strength between the side frame 20 and the cross member 40.

[0063] Further improvements to the battery case 10 described above are listed below. 7(a), as indicated by the arrow (1), the flange portion 25 on the side frame 20 side is placed on the first floor portion 46 on the cross member 40 side. Alternatively, the second floor portion 52 on the cross member 40 side is placed on the flange portion 25 on the side frame 20 side.

[0064] As shown in FIG. 7(b), the flange portion 25 and the first floor portion 46 (or the second floor portion 52) are joined by welding. Since the flange portion 25 on the side frame 20 side is joined to the first floor portion 46 or the second floor portion 52 on the cross member 40 side, the joining strength between the side frame 20 and the cross member 40 can be increased. In particular, since the joining strength at the inner corners of the frame body 13 is increased, the strength of the frame body 13 can be increased. In addition, since the flange portion 25 and the first floor portion 46 (or the second floor portion 52) are connected, the supporting rigidity of the bottom plate 12 is increased.

[0065] FIG. 7(d) is a view taken along the arrow d in FIG. 7(b). As shown in FIG. 7( d ), it is recommended that the edge of the bottom plate 12 be bent in a stepped shape to prevent a gap from being generated between the flange portion 25 and any of the first floor portion 46 and the second floor portion 52 .

[0066] 7(c), an upper corner of the first wall portion 47 (or the second wall portion 53) on the cross member 40 side is formed as an end extension portion 63 extending along the arc portion 29. The end extension portion 63 is cut out in an arc shape with a curvature radius R. It becomes possible to weld the end extensions 63 to the arc portions 29, which can further increase the joint strength between the side frames 20 and the cross members 40. In particular, the joint strength at the corners of the frame body 13 is increased, which can further increase the strength of the frame body.

[0067] [Intermediate plate] FIG. 8(a) is a reprint of FIG. 3(b). As shown in Fig. 8(b), in the cross member 40, an intermediate plate 64 is horizontally disposed between the first wall portion 47 and the second wall portion 53. This intermediate plate 64 is provided at the same height as the partition plate portion 35 shown in Fig. 8(a). Since the intermediate plate 64 is disposed between the first wall portion 47 and the second wall portion 53, the strength of the cross member 40 is increased.

[0068] In addition, since the partition plate portion 35 on the side frame 20 side and the intermediate plate 64 on the cross member 40 side are the same height, the horizontal force applied to the partition plate portion 35 is smoothly transmitted to the intermediate plate 64, and the horizontal force applied to the intermediate plate 64 is smoothly transmitted to the partition plate portion 35, thereby increasing the supporting rigidity of the frame body 13.

[0069] [Horizontal groove] FIG. 9(b) is an enlarged view of part b in FIG. 9(a). As shown in FIG. 9(b), a horizontal groove 66 may be provided on the inner surface of the outer wall portion 32. FIG. 9(d) is an enlarged view of part d in FIG. 9(c). 9(d), the tip of the partition plate portion 35 is inserted into the horizontal groove 66. A laser beam 23 is emitted from the outside of the outer wall portion 32 by the laser torch 22, and the partition plate portion 35 is joined to the outer wall portion 32.

[0070] In Fig. 3(b), when the laser beam 23 is emitted from the laser torch 22 from outside the outer wall 32, the partition plate 35 cannot be seen from the outside, but since the horizontal groove 66 is located at a fixed position by design as shown in Fig. 9(d), welding is easy. Also, if holes are drilled partially, confirmation and welding become even easier.

[0071] [First and second shock absorbing members] As shown in Figure 10, in the side frame 20, it is recommended that a first impact absorbing member 72 be placed in the first floor space 71 below the partition board portion 35, and a second impact absorbing member 74 be placed in the second floor space 73 above the partition board portion 35.

[0072] The collision energy is absorbed by the member due to the plastic deformation of the member. For the sake of convenience, in the present invention, the absorption of energy is also referred to as the absorption of a side impact load. The side impact load 75 applied to the side frame 20 is a substantially horizontal force, and is therefore absorbed mainly by plastic deformation of the partition plate portion 35. The side impact load 75 is a collision force applied substantially horizontally from the outside.

[0073] At this time, the second impact absorbing member 74 and the first impact absorbing member 72 arranged above and below the partition plate portion 35 also undergo plastic deformation, thereby absorbing the side impact load 75 . That is, the second impact absorbing member 74 and the first impact absorbing member 72 cooperate with the partition plate portion 35 to reliably absorb the side impact load 75 .

[0074] [Cover and extension piece] As shown in Fig. 11(a), when the ends of the side frames 20 are open, foreign matter such as dirt and sand can get into the side frames 20 and cause dirt. Also, when the ends of the side frames 20 are open, the strength of the open ends cannot be said to be high. A countermeasure to this is shown in Fig. 11(b).

[0075] As shown in FIG. 11( b ), a rear fastening member 44 is connected (joined) to the end of the side frame 20 . The rear fastening member 44 is a multi-purpose member having a cover member 77 that closes the end of the side frame 20, an extension piece 78 that protrudes from this cover member 77, and a protection plate support portion 79 that protrudes from the cover member 77.

[0076] By joining the extension piece 78 to the cross member 40, the joining strength between the side frame 20 and the cross member 40 can be increased. When a protection plate (FIG. 1, reference numeral 16) is fastened to the protection plate support portion 79, the protection plate is stably attached to the battery case. [Industrial Applicability]

[0077] The present invention is suitable for a battery case mounted on a vehicle. [Explanation of symbols]

[0078] 10...battery case, 11...battery, 12...bottom plate, 13...frame, 16...protective plate, 17...cooling plate, 20...side frame, 25...flange portion, 26...extension portion, 27...first floor inner wall portion, 28...second floor inner wall portion (inner wall portion), 29...arc portion, 31...upper plate portion, 32...outer wall portion, 33...lower plate portion, 34...internal wall portion, 35...partition plate portion, 40...cross member, 43...vehicle mounting mounting member, 45...first member, 46...first floor portion, 47...first wall portion, 48...first ceiling portion, 51...second member, 52...second floor portion, 53...second wall portion, 54...second ceiling portion, 58...tongue piece, 59...connecting piece, 63...end extension portion, 64...intermediate plate, 66...horizontal groove, 71...first floor space, 72...first impact absorbing member, 73...second floor space, 74...second impact absorbing member, 77...cover member, 78...extension piece, W...predetermined distance.

Claims

1. A battery case comprising a bottom plate supporting a battery and a frame surrounding the battery placed on the bottom plate, The frame body is made up of left and right side frames and cross members extending between the front and rear ends of the side frames, The side frame is formed by plastic working a single metal plate to form a closed cross section, and the closed cross section has at least an arc portion between an upper plate portion and an upper end of an inner wall portion, The cross member has a tongue that extends beyond the arc portion and is joined to the upper plate portion.

2. The battery case according to claim 1, The side frame is composed of a flange portion supporting the bottom plate, an extension portion extending upward from the flange portion, an inner wall first floor portion extending upward from the extension portion, an inner wall second floor portion as the inner wall portion extending upward from the inner wall first floor portion, an upper plate portion extending horizontally outward from the upper end of the inner wall second floor portion via an arc portion, an outer wall portion extending downward from the tip of the upper plate portion, a lower plate portion extending horizontally from the lower end of the outer wall portion toward the inner wall first floor portion, an inner wall portion extending upward from the tip of the lower plate portion while following the inner wall first floor portion, and a partition plate portion extending horizontally from the upper end of the inner wall portion to the outer wall portion, and the inner wall first floor portion and the inner wall portion form a double wall structure, The battery case is characterized in that the extension portion and the flange portion form an L-shaped cross-sectional portion.

3. The battery case according to claim 1, The cross member is a first member having the same shape as a light Z-shaped steel, the first member includes a first floor portion extending horizontally toward the inside of the battery case, a first wall portion extending upward from the first floor portion, and a first ceiling portion extending horizontally from an upper end of the first wall portion in a direction opposite to the first wall portion, A battery case characterized in that a connecting piece is attached to the first wall portion and is joined to the inner wall portion of the side frame.

4. The battery case according to claim 3, A second member having the same shape as the light Z-shaped steel is fitted and joined to the first member, the second member comprising a second floor portion extending horizontally so that the first floor portion can be placed on it, a second wall portion extending upward from the second floor portion, and a second ceiling portion extending horizontally so that the first ceiling portion can be placed on it, the second wall portion being spaced a predetermined distance from the first wall portion along the longitudinal axis of the side frame, A battery case characterized in that the two components are joined with the second floor portion placed on the flange portion, or the two components are joined with the flange portion placed on the first floor portion.

5. The battery case according to claim 4, A battery case comprising: a first wall portion and a second wall portion, the first wall portion and the second wall portion being disposed at the same height as the partition plate portion.

6. The battery case according to claim 3, A battery case characterized in that at least one of the first wall portion and the second wall portion has an end extension portion extending along the arc portion.

7. The battery case according to claim 1, The battery case is characterized in that the outer wall portion has a horizontal groove that accommodates the tip of the partition plate portion.

8. The battery case according to claim 1, A battery case characterized in that a first impact absorbing member is arranged in a first floor space below the partition plate portion, and a second impact absorbing member is arranged in a second floor space above the partition plate portion.

9. The battery case according to claim 1, The side frame has an open end which is covered by a cover member, and an extension piece which extends to and is joined to the cross member is integrally formed with the cover member.

10. The battery case according to claim 3, a vehicle body mounting member is attached to the outer wall portion, a cooling plate is disposed under the bottom plate, and a protection plate is disposed under the cooling plate; The battery case is characterized in that the protective plate is fixed to the vehicle body mounting member and the second floor portion.

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