Battery pack

Abstract

A battery pack (10) comprises a battery cell (100) and a housing (200) that houses the battery cell (100). The housing (200) has: a seal (240) that includes a second extending portion (240b), a fourth extending portion (240d), and an oblique extending portion (240f) which extend obliquely with respect to each other; and an inner wall (223a) and outer wall (223b) that are respectively positioned on both sides of the seal (240). The inner wall (223a) and the outer wall (223b) are disposed substantially parallel to the second extending portion (240b), the fourth extending portion (240d), and the oblique extending portion (240f).

Description

Battery pack

[0001] The present invention relates to a battery pack.

[0002] In recent years, various battery packs have been developed. A battery pack includes a battery cell and a housing that houses the battery cell.

[0003] Patent Document 1 describes a battery pack. The battery pack includes a housing that has an opening and houses a battery module, a sealing material provided around the opening of the housing, and a lid that closes the opening of the housing.

[0004] Japanese Unexamined Patent Application Publication No. 2015-149147

[0005] (Aspect 1) The seal of the housing of the battery pack may have a plurality of portions that extend obliquely to each other. When the seal has a plurality of portions that extend obliquely to each other, it may be difficult to enhance the sealing performance of the seal.

[0006] An example of the object of Aspect 1 of the present invention is to enhance the sealing performance of the seal when the seal of the housing of the battery pack has a plurality of portions that extend obliquely to each other. Other objects of Aspect 1 of the present invention will become apparent from the description herein.

[0007] (Aspect 2) The housing of the battery pack may have a plurality of structures welded to each other, and a seal that at least partially overlaps a welding mark formed at a welded portion of the plurality of structures. When the seal and the welding mark overlap each other, it may be difficult to enhance the sealing performance of the seal.

[0008] An example of the object of Aspect 2 of the present invention is to enhance the sealing performance of the seal in a state where the seal and the welding mark overlap each other. Other objects of Aspect 2 of the present invention will become apparent from the description herein.

[0009] One aspect of the present invention is as follows: 1.1 A battery pack comprising: a battery cell; and a housing for housing the battery cell, wherein the housing has a seal including a plurality of parts extending diagonally from each other; and walls located on both sides of the seal, the walls being arranged substantially parallel to the plurality of parts of the seal. 1.2 The battery pack according to 1.1, wherein the housing has a side frame; the side frame includes a plurality of structures welded to each other; the plurality of structures include a portion of the wall; and the portion of the wall of the plurality of structures is arranged substantially parallel to the plurality of parts of the seal and is connected to each other. 1.3 The battery pack according to 1.2, wherein the weld marks located at the welded portions of the side frame and the structures and overlapping with the seal are at least partially smoothed. 1.4 The battery pack according to any one of 1.1 to 1.3, wherein the housing has a side surface located outside the housing with respect to the seal; the side surface of the housing and the seal are arranged at least partially substantially parallel to each other.

[0010] A second aspect of the present invention is as follows: 2.1 A battery pack comprising: a battery cell; and a housing for housing the battery cell, wherein the housing has a plurality of structures welded to each other; and a seal that at least partially overlaps with the weld marks formed at the locations where the plurality of structures are welded to each other, and the portion of the weld marks that overlaps with the seal is at least partially smoothed. 2.2 The battery pack according to 2.1, wherein the weld marks include a portion that is raised above the smoothed portion of the weld marks. 2.3 The battery pack according to 2.2, wherein the seal has a shape that at least partially avoids the raised portion. 2.4 The battery pack according to 2.3, wherein the shape of the seal is formed by a notch in the seal. 2.5 The battery pack according to 2.3, wherein the shape of the seal is formed by a thin-walled portion of the seal.

[0011] According to embodiment 1 of the present invention, when the seal of the battery pack housing has multiple parts that extend diagonally from each other, the sealing performance of the seal can be improved.

[0012] According to aspect 2 of the present invention, the sealing performance of the seal can be improved when the seal and the weld marks overlap each other.

[0013] This is a perspective view of the battery pack according to the embodiment. This is a top view of the battery pack according to the embodiment with the upper plate transparently displayed. This is an enlarged view of region α shown in Figure 2. This is a cross-sectional view along line A-A in Figure 3. This is an enlarged view of region β shown in Figure 2. This is an enlarged perspective view of region γ shown in Figure 2.

[0014] Embodiments of the present invention will be described below with reference to the drawings. In all drawings, similar components are denoted by the same reference numerals, and their descriptions are omitted where appropriate.

[0015] Figure 1 is a perspective view of the battery pack 10 according to the embodiment. Figure 2 is a top view of the battery pack 10 according to the embodiment with the upper plate 230 shown transparently. Figure 3 is an enlarged view of the region α shown in Figure 2. Figure 4 is a cross-sectional view along the line A-A in Figure 3. In Figure 2, the protrusion 242, which will be described later using Figure 3, is omitted. In Figures 2 and 3, the upper plate 230 is shown transparently so that the part of the battery pack 10 that is hidden by the upper plate 230 is visible. Therefore, in Figures 2 and 3, it appears as if the upper plate 230 shown in Figures 1 and 4 has been removed.

[0016] In this embodiment, the battery pack 10 is mounted in an automobile. Specifically, the battery pack 10 is mounted between the front and rear wheels of the automobile. Hereafter, unless otherwise specified, the battery pack 10 will be described as being mounted in an automobile. However, the battery pack 10 can also be applied to applications other than automobiles.

[0017] Each figure shows the X, Y, and Z directions for illustrative purposes. The X direction indicates the front-to-back direction of the battery pack 10. The Y direction is one of the directions perpendicular to the X direction. The Y direction indicates the left-to-right direction of the battery pack 10. The Z direction is perpendicular to both the X and Y directions. The Z direction indicates the up-to-down direction of the battery pack 10. The arrows pointing to the X direction, the Y direction, and the Z direction indicate the front, left, and up directions of the battery pack 10, respectively. In Figures 2 and 3, the white circle with a black dot indicating the Z direction indicates that the arrow pointing to the Z direction extends from the back of the page to the front. In Figure 4, the white circle with an X indicating the X direction indicates that the arrow pointing to the X direction extends from the front of the page to the back. The relationship between the X, Y, and Z directions and the front-to-back, left-to-right, and up-to-down directions of the battery pack 10 is not limited to this example.

[0018] In this embodiment, the front-to-back, left-to-right, and up-to-down directions of the battery pack 10 are determined by the vehicle in which the battery pack 10 is mounted. The X, Y, and Z directions represent the front-to-back, left-to-right, and up-to-down directions of the vehicle, respectively. The arrows pointing to the X, Y, and Z directions represent the front, left, and up directions of the vehicle, respectively. However, the relationship between the front-to-back, left-to-right, and up-to-down directions of the battery pack 10 and the front-to-back, left-to-right, and up-to-down directions of the vehicle is not limited to this example.

[0019] Hereafter, where necessary, the side indicated by the arrow showing the X direction will be referred to as the +X side, and the opposite side of the side indicated by the arrow showing the X direction will be referred to as the -X side. Hereafter, where necessary, the side indicated by the arrow showing the Y direction will be referred to as the +Y side, and the opposite side of the side indicated by the arrow showing the Y direction will be referred to as the -Y side. Hereafter, where necessary, the side indicated by the arrow showing the Z direction will be referred to as the +Z side, and the opposite side of the side indicated by the arrow showing the Z direction will be referred to as the -Z side. Hereafter, unless otherwise specified, the horizontal direction refers to the direction perpendicular to the Z direction.

[0020] As shown in Figures 1 and 2, the battery pack 10 comprises a plurality of battery cells 100 and a housing 200. As shown in Figure 2, the housing 200 forms a housing space 202 that accommodates the plurality of battery cells 100.

[0021] In the example shown in Figure 2, the battery pack 10 comprises a plurality of battery cells 100 housed in the front part of the housing space 202 on the +X side, and a plurality of other battery cells 100 housed in the rear part of the housing space 202 on the -X side. Hereafter, unless otherwise specified, the plurality of battery cells 100 on the front side refers to the plurality of battery cells 100 housed in the front part of the housing space 202 on the +X side, and the plurality of battery cells 100 on the rear side refers to the plurality of other battery cells 100 housed in the rear part of the housing space 202 on the -X side.

[0022] In the example shown in Figure 2, each battery cell 100 has a pair of faces substantially perpendicular to the X direction, a pair of faces substantially perpendicular to the Y direction, and a pair of faces substantially perpendicular to the Z direction, and has a substantially rectangular parallelepiped shape in which the dimension in the Z direction is less than the dimension in the X direction and greater than the dimension in the Y direction. The shape of each battery cell 100 is not limited to the example shown in Figure 2. As shown in Figure 2, the multiple battery cells 100 on the front side are stacked in the Y direction and are electrically connected to each other in series, parallel, or a combination of series and parallel. As shown in Figure 2, the multiple battery cells 100 on the rear side are stacked in the Y direction and are electrically connected to each other in series, parallel, or a combination of series and parallel. The arrangement of the multiple battery cells 100 is not limited to the example shown in Figure 2. For example, the multiple battery cells 100 may be stacked in the X direction. In addition, multiple other battery cells 100 may be housed in addition to the multiple battery cells 100 on the front side and the multiple battery cells 100 on the rear side.

[0023] The front battery cells 100 may be housed in a separate housing (not shown) provided separately from the housing 200, and housed in the front +X side of the housing space 202. Alternatively, the front battery cells 100 may be housed directly in the front +X side of the housing space 202 without being housed in a separate housing provided separately from the housing 200. The same applies to the rear battery cells 100.

[0024] As shown in Figures 1 and 2, the housing 200 includes a lower plate 210, a side frame 220, an upper plate 230, and a seal 240. The lower plate 210 and the side frame 220 are sometimes collectively referred to as the lower case. The upper plate 230 is sometimes referred to as the upper case.

[0025] The lower plate 210 is positioned substantially perpendicular to the Z direction. The multiple battery cells 100 are located on the +Z side relative to the +Z side surface of the lower plate 210. As shown in Figure 2, the lower plate 210 has a substantially quadrilateral shape with a pair of sides substantially parallel to the X direction and another pair of sides substantially parallel to the Y direction. The shape of the lower plate 210 is not limited to the example shown in Figure 2.

[0026] The side frame 220 extends from the entire circumference of the +Z side surface of the lower plate 210 toward the +Z side. As shown in Figure 2, when viewed from the Z direction, the side frame 220 extends to surround the entire housing space 202. Hereafter, unless otherwise specified, the inside of the housing 200 refers to the side where the housing space 202 is located relative to the side frame 220 when viewed from the Z direction, and the outside of the housing 200 refers to the opposite side of the side where the housing space 202 is located relative to the side frame 220 when viewed from the Z direction. As shown in Figure 2, the side frame 220 includes a first structure 220a that covers the -X side portion of the housing space 202 and extends in the Y direction, a second structure 220b that covers the +X side portion of the housing space 202 and extends in the Y direction, a third structure 220c that covers the -Y side portion of the housing space 202 and extends in the X direction, and a fourth structure 220d that covers the +Y side portion of the housing space 202 and extends in the X direction.

[0027] As shown in Figure 4, the side frame 220 includes a side upper plate 222, an inner side wall 224a, and an outer side wall 224b.

[0028] As shown in Figure 4, the side upper plate 222 is positioned approximately perpendicular to the Z direction. The inner wall 223a and the outer wall 223b protrude from the upper surface of the side upper plate 222 on the +Z side. The inner wall 223a and the outer wall 223b face each other, with the inner wall 223a located inside the housing 200 relative to the outer wall 223b, and the outer wall 223b located outside the housing 200 relative to the inner wall 223a.

[0029] As shown in Figure 4, the groove 223 is defined by the upper surface of the side upper plate 222 on the +Z side, and the opposing sides of the inner wall 223a and outer wall 223b. As shown in Figure 4, the groove 223 opens upward on the +Z side. As shown in Figure 2, when viewed from the Z direction, the groove 223 extends to surround the entire housing space 202. Hereafter, unless otherwise specified, the inner edge of the groove 223 refers to the edge located inside the housing 200 of the groove 223 when viewed from the Z direction, and the outer edge of the groove 223 refers to the edge located outside the housing 200 of the groove 223 when viewed from the Z direction. The inner edge of the groove 223 corresponds to the side of the inner wall 223a that is located outside the housing 200 when viewed from the Z direction. The outer edge of the groove 223 corresponds to the side of the outer wall 223b that is located inside the housing 200 when viewed from the Z direction. Unless otherwise specified, the width of the groove 223 refers to the width of the groove 223 in the direction from the inner edge of the groove 223 to the outer edge of the groove 223 when viewed from the Z direction.

[0030] As shown in Figure 4, the inner side wall 224a extends toward the -Z side from the end of the side upper plate 222 located inside the housing 200. As shown in Figure 4, the outer side wall 224b extends toward the -Z side from the end of the side upper plate 222 located outside the housing 200. As shown in Figure 4, a hollow space 225 is defined inside the side frame 220 by the -Z side lower surface of the side upper plate 222 and the opposing sides of the inner side wall 224a and the outer side wall 224b.

[0031] As shown in Figure 1, the upper plate 230 is located on the +Z side relative to the side frame 220. The upper plate 230 includes a raised portion 232 and an extended portion 234. The raised portion 232 rises upward on the +Z side relative to the lower plate 210 and the side frame 220. The extended portion 234 extends horizontally outward from the lower end of the raised portion 232 on the +Z side, in a direction substantially perpendicular to the Z direction.

[0032] The seal 240 is an elastic material such as rubber or elastomer. As shown in Figure 4, the seal 240 is positioned within the groove 223. As shown in Figure 2, the seal 240 extends to surround the entire housing space 202, similar to the groove 223. Hereafter, unless otherwise specified, the inner edge of the seal 240 refers to the edge of the seal 240 facing inward from the housing 200 when viewed from the Z direction, and the outer edge of the seal 240 refers to the edge of the seal 240 facing outward from the housing 200 when viewed from the Z direction. Hereafter, unless otherwise specified, the width of the seal 240 refers to the width of the seal 240 in the direction from the inner edge to the outer edge of the seal 240 when viewed from the Z direction. As shown in Figure 2, the seal 240 includes a first extending portion 240a provided on the first structure 220a and extending in the Y direction, a second extending portion 240b provided on the second structure 220b and extending in the Y direction, a third extending portion 240c provided on the third structure 220c and extending in the X direction, and a fourth extending portion 240d provided on the fourth structure 220d and extending in the X direction.

[0033] The details of the side frame 220, upper plate 230, and seal 240 will be described with reference to Figures 3 and 4.

[0034] As shown in Figure 4, the side upper plate 222 and the extension portion 234 are fastened together by fasteners including rivet nuts 250 and bolts 260, with the seal 240 positioned between the side upper plate 222 and the extension portion 234. As shown in Figures 3 and 4, the seal 240 is positioned between the side upper plate 222 and the extension portion 234 with the inner wall 223a located inside the housing 200 relative to the seal 240 and the outer wall 223b located outside the housing 200 relative to the seal 240. Therefore, the seal 240 can be positioned with its inner edge and outer edge aligned with the inner wall 223a and outer wall 223b, respectively. As shown in Figure 4, the seal 240 defines an opening 241 through which the fasteners including rivet nuts 250 and bolts 260 pass in the Z direction. The housing 200 forms a housing space 202 by fastening the side upper plate 222 and the extended portion 234 to each other. The seal 240 is compressed in the Z direction by the side upper plate 222 and the extended portion 234 while the side upper plate 222 and the extended portion 234 are fastened to each other by rivet nuts 250 and bolts 260. By compressing the seal 240 in the Z direction, the area between the side upper plate 222 and the extended portion 234 can be sealed.

[0035] As shown in Figure 4, the rivet nut 250 includes a nut shaft 252 and a nut head 254. The nut shaft 252 penetrates the side upper plate 222 in the Z direction with its lower end on the -Z side located within the hollow space 225. The nut shaft 252 includes a wide portion 253 located on the -Z side relative to the -Z side surface of the side upper plate 222. The wide portion 253 is formed by the deformation of the nut shaft 252 outward in the horizontal direction. The horizontal diameter of the wide portion 253 is larger than the horizontal diameter of both sides of the wide portion 253 in the Z direction of the nut shaft 252. The nut head 254 is provided at the upper end of the nut shaft 252 on the +Z side. The nut head 254 is located on the +Z side relative to the +Z side surface of the side upper plate 222 and is located within the opening 241 of the seal 240. The horizontal diameter of the nut head 254 is larger than the horizontal diameter of the nut shaft 252. The side upper plate 222 and the rivet nut 250 are fastened to each other with the wide portion 253 and the nut head 254 clamping the side upper plate 222 in the Z direction.

[0036] As shown in Figure 4, the bolt 260 includes a bolt shaft 262 and a bolt head 264. The rivet nut 250 and the bolt 260 are screwed together with the bolt shaft 262 inserted through the nut shaft 252 and nut head 254 in the Z direction. In the example shown in Figure 4, even if it is difficult to provide a screw hole in the side upper plate 222 for screwing the bolt 260 due to the relatively thin thickness of the side upper plate 222 in the Z direction, the bolt 260 can still be screwed to the rivet nut 250 provided on the side upper plate 222. The bolt head 264 is located on the +Z side with respect to the +Z side surface of the extended portion 234. With the rivet nut 250 and the bolt 260 screwed together, the side upper plate 222 and the extended portion 234 are fastened together.

[0037] The fastening of the side upper plate 222 and the extended portion 234 is not limited to the example shown in Figure 4. For example, even if the rivet nut 250 is not provided on the side upper plate 222, the bolt 260 may be screwed into a threaded hole provided on the side upper plate 222.

[0038] As shown in Figure 3, when viewed from the Z direction, a plurality of protrusions 242 are provided on the inner edge and outer edge of the seal 240 around the opening 241 in region α. ​​As shown in Figure 2, region α is a portion of the region located on the +Y side with respect to the housing space 202 of the side frame 220. As shown in Figure 3, around the opening 241 in region α, the seal 240 has two protrusions 242 projecting from the inner edge of the seal 240 toward the inner wall 223a, and two other protrusions 242 projecting from the outer edge of the seal 240 toward the outer wall 223b. In the example shown in Figure 3, each protrusion 242 is positioned offset from the plane containing the center of the bolt head 264, perpendicular to the inner edge or outer edge of the seal 240 when viewed from the Z direction. In the example shown in Figure 3, the line A-A corresponds to the plane containing the center of the bolt head 264, perpendicular to the inner edge or outer edge of the seal 240 when viewed from the Z direction. As shown in Figure 3, in region α, on the -X side with respect to the A-A line, there are two protrusions 242 projecting away from each other from the inner edge and outer edge of the seal 240, and on the +X side with respect to the A-A line, there are two other protrusions 242 projecting away from each other from the inner edge and outer edge of the seal 240.

[0039] In region α shown in Figure 3, the width WT of the groove 223 in the Y direction is approximately constant regardless of the position of the groove 223 in the X direction. In region α shown in Figure 3, the width WS1 of the seal 240 in the Y direction between the two protrusions 242 located on the -X side with respect to the A-A line, and the width WS2 of the seal 240 in the Y direction between the other two protrusions 242 located on the +X side with respect to the A-A line, are wider than the width WS of the seal 240 in the Y direction in other parts of the seal 240, and are less than the width WT of the groove 223 in the Y direction.

[0040] In the examples shown in Figures 3 and 4, the width of the seal 240 can be partially brought closer to the width WT of the groove 223 by the projection 242. Therefore, compared to the case where the width of the seal 240 is equal to the width WS shown in Figure 3 throughout the entire seal 240 without the projection 242, horizontal displacement of the seal 240 within the groove 223 can be suppressed. If displacement of the seal 240 occurs, a portion of the seal 240 may be inserted between the -Z side surface of the extended portion 234 and the +Z side surface of the nut head 254, and the side upper plate 222 and the extended portion 234 may be fastened together by the rivet nut 250 and bolt 260. The insertion of a portion of the seal 240 between the -Z side surface of the extended portion 234 and the +Z side surface of the nut head 254 may have an undesirable effect on the sealing of the seal 240. In the examples shown in Figures 3 and 4, the misalignment of the seal 240 is suppressed, thereby preventing a portion of the seal 240 from entering the space between the -Z side surface of the extended portion 234 and the +Z side surface of the nut head 254. Therefore, in the examples shown in Figures 3 and 4, compared to the case where the seal 240 does not have the projection 242, it is possible to easily position the seal 240 appropriately during the assembly of the battery pack 10.

[0041] In the examples shown in Figures 3 and 4, the width of the seal 240 does not need to be close to the width WT of the groove 223 across the entire seal 240. Therefore, compared to the case where the width of the seal 240 is equal to the width WS1 or width WS2 shown in Figure 3 across the entire seal 240, the precision required for positioning the seal 240 within the groove 223 can be reduced. Consequently, compared to the case where the width of the seal 240 is equal to the width WS1 or width WS2 shown in Figure 3 across the entire seal 240, it is easier to position the seal 240 in the correct location during the assembly of the battery pack 10. Furthermore, compared to the case where the width of the seal 240 is equal to the width WS1 or width WS2 shown in Figure 3 across the entire seal 240, the horizontal inward spreading of the seal 240 when the seal 240 is compressed in the Z direction by the side upper plate 222 and the extended portion 234 can be suppressed. By suppressing the horizontal inward expansion of the seal 240, it is possible to prevent a portion of the seal 240 from penetrating between the -Z side surface of the extended portion 234 and the +Z side surface of the nut head 254.

[0042] In the examples shown in Figures 3 and 4, it is not necessary to provide the projections 242 on both sides in the Y direction relative to the center of the bolt head 264 when viewed from the Z direction. Therefore, compared to the case where the projections 242 are located on both sides in the Y direction of the center of the bolt head 264, even if the seal 240 is compressed in the Z direction by the side upper plate 222 and the extended portion 234 and the seal 240 near the projections 242 expands horizontally inward, it is possible to suppress the intrusion of a portion of the seal 240 between the -Z side surface of the extended portion 234 and the +Z side surface of the nut head 254.

[0043] The configuration of region α described using Figures 3 and 4 can also be applied to other regions of the side frame 220.

[0044] FIG. 5 is an enlarged view of the region β shown in FIG. 2. The matters to be described using FIG. 5 are not only the corners between the first structure 220a and the third structure 220c in the side frame 220, but also, for example, the corners between the first structure 220a and the fourth structure 220d in the side frame 220, the corners between the second structure 220b and the third structure 220c in the side frame 220, or the corners between the second structure 220b and the fourth structure 220d in the side frame 220.

[0045] In the example shown in FIG. 5, the -Y side end of the first structure 220a and the -X side end of the third structure 220c are welded. Therefore, as shown in FIG. 5, a first weld mark 221a is formed at the welded portion of the -Y side end of the first structure 220a and the -X side end of the third structure 220c. The first weld mark 221a is located on the +Z side surface side of the first structure 220a and the third structure 220c.

[0046] As shown in FIG. 5, the seal 240 includes a bent portion 240e located between the -Y side end of the first extending portion 240a and the +X side end of the third extending portion 240c. When viewed from the Z direction, the seal 240 is bent at a substantially right angle at the bent portion 240e. The bending angle of the bent portion 240e is not limited to the substantially right angle shown in FIG. 5 and may vary depending on, for example, the shape of the side frame 220.

[0047] As shown in FIG. 5, when viewed from the Z direction, the inner wall 223a of the first structure 220a and the inner wall 223a of the third structure 220c are bent at a substantially right angle around the bent portion 240e. The bending angle of the inner wall 223a around the bent portion 240e is not limited to the substantially right angle shown in FIG. 5 and may vary depending on, for example, the shape of the seal 240.

[0048] As shown in FIG. 5, when viewed from the Z direction, the outer wall 223b of the first structure 220a and the outer wall 223b of the third structure 220c are divided by the first weld mark 221a around the bent portion 240e. When viewed from the +Z side, the outer wall 223b of the first structure 220a and the outer wall 223b of the third structure 220c extend in directions that are approximately 90 degrees different from the first weld mark 221a. The angle formed by the extending direction of the outer wall 223b of the first structure 220a and the extending direction of the outer wall 223b of the third structure 220c is not limited to the approximately 90 degrees shown in FIG. 5 and may vary depending on, for example, the shape of the seal 240. Hereinafter, unless otherwise specified, the included angle portion 223c of the outer wall 223b refers to the portion sandwiched by the outer wall 223b of the first structure 220a and the outer wall 223b of the third structure 220c around the first weld mark 221a.

[0049] As shown in FIG. 5, the first weld mark 221a and the bent portion 240e at least partially overlap each other in the Z direction. The first weld mark 221a may protrude on the +Z side from the +Z side surfaces of the first structure 220a and the +Z side surface of the third structure 220c. In the embodiment, the portion of the first weld mark 221a that overlaps the bent portion 240e in the Z direction is at least partially flattened so that the +Z side surface of the first structure 220a, the +Z side surface of the third structure 220c, and the first weld mark 221a are substantially flush. Therefore, the sealing performance of the bent portion 240e can be improved as compared with the case where the portion of the first weld mark 221a that overlaps the bent portion 240e in the Z direction is not flattened.

[0050] As can be seen from FIG. 5, the gap of the included angle portion 223c of the outer wall 223b narrows as it approaches the vertex of the included angle portion 223c. Therefore, the first weld mark 221a may be difficult to flatten in the included angle portion 223c of the outer wall 223b. Accordingly, the protrusion of the first weld mark 221a in the included angle portion 223c of the outer wall 223b may remain as it is. That is, in the included angle portion 223c of the outer wall 223b, the first weld mark 221a may include a portion that protrudes on the +Z side from the portion that overlaps the bent portion 240e of the first weld mark 221a in the Z direction.

[0051] In this embodiment, as shown in Figure 5, a notch 243 is provided on the outer edge of the bent portion 240e. The notch 243 gives the outer edge of the bent portion 240e a shape that at least partially avoids the protrusion of the first weld mark 221a. Therefore, even if the protrusion of the first weld mark 221a remains at the corner portion 223c of the outer wall 223b, the sealing performance of the bent portion 240e can be improved compared to the case where the protrusion of the first weld mark 221a and the bent portion 240e overlap each other in the Z direction. Furthermore, the remaining protrusion of the first weld mark 221a at the corner portion 223c of the outer wall 223b makes it easier to improve the strength of the first weld mark 221a.

[0052] The shape that at least partially avoids the protrusion of the first weld mark 221a in the bent portion 240e is not limited to the notch 243 shown in Figure 5. For example, a thin-walled portion of the bent portion 240e may be provided in the portion that overlaps with the protrusion of the first weld mark 221a in the Z direction. The thickness in the Z direction of the thin-walled portion of the bent portion 240e is less than the thickness in the Z direction of the portion surrounding the thin-walled portion of the bent portion 240e. Therefore, compared to the case where the thickness in the Z direction of the portion that overlaps with the protrusion of the first weld mark 221a in the Z direction of the bent portion 240e is relatively thick, interference between the protrusion of the first weld mark 221a and the bent portion 240e can be suppressed, and the sealing performance of the bent portion 240e can be improved.

[0053] As can be seen from the explanation using Figure 5, the shape that avoids at least partially the protrusion of the first weld mark 221a in the bent portion 240e may be provided on the inner edge of the seal 240 rather than the outer edge of the seal 240, depending on the shape of the seal 240. For example, if a structure corresponding to the corner portion 223c of the outer wall 223b is provided on the inner wall 223a, the shape that avoids at least partially the protrusion of the first weld mark 221a in the bent portion 240e may be provided on the inner edge of the seal 240.

[0054] Figure 6 is an enlarged perspective view of region γ shown in Figure 2. In Figure 6, for illustrative purposes, the seal 240 is shown transparently with its outline indicated by a dashed line. The matters described using Figure 6 are applicable not only to the corner between the second structure 220b and the fourth structure 220d in the side frame 220, but also, for example, the corner between the second structure 220b and the third structure 220c in the side frame 220, the corner between the first structure 220a and the third structure 220c in the side frame 220, or the corner between the first structure 220a and the fourth structure 220d in the side frame 220.

[0055] The battery pack 10 will be described primarily with reference to Figure 6. Figure 2 may be referenced as needed.

[0056] As shown in Figure 6, when viewed from the Z direction, the corner located between the +Y end of the +X side surface of the second structure 220b and the +X end of the +Y side surface of the fourth structure 220d in the side frame 220 is formed at an angle to the +X side surface of the second structure 220b and the +Y side surface of the fourth structure 220d. Specifically, when viewed from the Z direction, the corner located between the +Y end of the +X side surface of the second structure 220b and the +X end of the +Y side surface of the fourth structure 220d in the side frame 220 is chamfered. Therefore, the side frame 220 can be made smaller by the amount of the chamfered corner.

[0057] In the example shown in Figure 6, the chamfered corner of the side frame 220 located between the +Y end of the +X side of the second structure 220b and the +X end of the +Y side of the fourth structure 220d is covered by the fifth structure 220e. The side frame 220 has the fifth structure 220e. The fifth structure 220e includes an outer wall 223b that is connected to the +Y end of the outer wall 223b of the second structure 220b and the +X end of the outer wall 223b of the fourth structure 220d. Viewed from the Z direction, the outer wall 223b of the fifth structure 220e extends obliquely to the outer wall 223b that connects the outer wall 223b of the second structure 220b and the outer wall 223b of the fourth structure 220d.

[0058] As shown in Figure 6, the sixth structure 220f is located between the +Y end of the inner wall 223a of the second structure 220b and the +X end of the inner wall 223a of the fourth structure 220d. The side frame 220 has the sixth structure 220f. In the example shown in Figure 6, when viewed from the Z direction, the sixth structure 220f has a roughly right-angled triangular shape with one side extending to the +X side from the +X end of the inner wall 223a of the fourth structure 220d, one side extending to the +Y side from the +Y end of the inner wall 223a of the second structure 220b, and a hypotenuse extending between the +Y end of the inner wall 223a of the second structure 220b and the +X end of the inner wall 223a of the fourth structure 220d. The shape of the sixth structure 220f is not limited to the roughly right-angled triangle shown in Figure 6.

[0059] As shown in Figure 6, the sixth structure 220f includes an inner wall 223a that is connected to the +Y side end of the inner wall 223a of the second structure 220b and the +X side end of the inner wall 223a of the fourth structure 220d. Viewed from the Z direction, the inner wall 223a of the sixth structure 220f extends diagonally to the inner wall 223a of the second structure 220b and the inner wall 223a of the fourth structure 220d.

[0060] As shown in Figures 2 and 6, the seal 240 includes an obliquely extending portion 240f located between the +Y end of the second extending portion 240b and the +X end of the fourth extending portion 240d. Viewed from the Z direction, the obliquely extending portion 240f extends obliquely to the second extending portion 240b and the fourth extending portion 240d. In the example shown in Figures 2 and 6, the side surface of the housing 200 that is located outward from the seal 240 and the seal 240 are arranged at least partially substantially parallel to each other. For example, as shown in Figures 2 and 6, the obliquely extending portion 240f and the chamfered corner located between the +Y end of the +X side surface of the second structure 220b and the +X end of the +Y side surface of the fourth structure 220d are arranged substantially parallel to each other.

[0061] As shown in Figure 6, the inner wall 223a and outer wall 223b of the second structure 220b are arranged substantially parallel to the second extended portion 240b. Therefore, the width of the second extended portion 240b in the X direction can be secured by the inner wall 223a and outer wall 223b of the second structure 220b. As shown in Figure 6, the inner wall 223a and outer wall 223b of the fourth structure 220d are arranged substantially parallel to the fourth extended portion 240d. Therefore, the width of the fourth extended portion 240d in the Y direction can be secured by the inner wall 223a and outer wall 223b of the fourth structure 220d. As shown in Figure 6, the inner wall 223a of the sixth structure 220f and the outer wall 223b of the fifth structure 220e are arranged substantially parallel to the diagonally extended portion 240f. Therefore, the width of the diagonally extending portion 240f in a direction diagonal to the X or Y direction can be secured by the inner wall 223a of the sixth structure 220f and the outer wall 223b of the fifth structure 220e.

[0062] For example, if the outer wall 223b of the fifth structure 220e is provided and the inner wall 223a of the second structure 220b and the inner wall 223a of the fourth structure 220d form a substantially right-angle corner, it may become difficult to secure the width of the seal 240 around the corner between the inner wall 223a of the second structure 220b and the inner wall 223a of the fourth structure 220d. However, in this embodiment, by providing the inner wall 223a of the sixth structure 220f, the width of the diagonally extending portion 240f can be secured, and the sealing performance of the diagonally extending portion 240f can be improved.

[0063] In the example shown in Figure 6, the +Y side end of the second structure 220b and the +X side end of the fourth structure 220d are welded to each other. Therefore, as shown in Figure 6, a second weld mark 221b is formed at the welded location of the +Y side end of the second structure 220b and the +X side end of the fourth structure 220d. The second weld mark 221b is located on the +Z side of both the second structure 220b and the fourth structure 220d.

[0064] In the example shown in Figure 6, the +Z side of the second structure 220b and one side of the sixth structure 220f extending in the Y direction are welded to each other. Also, the +Z side of the fourth structure 220d and one side of the sixth structure 220f extending in the X direction are welded to each other. Therefore, as shown in Figure 6, a third weld mark 221c is formed on the side of the sixth structure 220f extending in the Y direction and the side of the sixth structure 220f extending in the X direction. In this embodiment, the sixth structure 220f can be retrofitted to the second structure 220b and the fourth structure 220d. Therefore, compared to the case where the second structure 220b, the fourth structure 220d and the sixth structure 220f are molded integrally beforehand, it is possible to assemble the second structure 220b, the fourth structure 220d and the sixth structure 220f to each other more easily.

[0065] As shown in Figure 6, the portions of the second weld mark 221b and the third weld mark 221c that overlap with the obliquely extending portion 240f in the Z direction are at least partially smoothed so that the +Z side surface of the second structure 220b, the +Z side surface of the fourth structure 220d, the +Z side surface of the sixth structure 220f, the second weld mark 221b, and the third weld mark 221c are substantially flush. Therefore, the sealing performance of the obliquely extending portion 240f can be improved compared to the case where the portions of the second weld mark 221b and the third weld mark 221c that overlap with the obliquely extending portion 240f in the Z direction are not smoothed.

[0066] The embodiments of the present invention have been described above with reference to the drawings, but these are merely examples of the present invention, and various other configurations can also be adopted.

[0067] In the embodiment, sealing of the region between the side upper plate 222 and the extended portion 234 using a seal 240 was described. The sealing described using the embodiment is applicable to sealing regions between multiple structural parts of the housing 200, including sealing of the region between the side upper plate 222 and the extended portion 234.

[0068] In the embodiment, the projection 242 of the seal 240 is provided on both the inner edge and the outer edge of the seal 240. However, the projection 242 of the seal 240 may be provided on only one of the inner edge or the outer edge of the seal 240. Even when the projection 242 is provided on only one of the inner edge or the outer edge of the seal 240, the width of the seal 240 can be partially brought closer to the width of the groove 223. Therefore, as described in the embodiment, it is possible to facilitate the proper positioning of the seal 240 during the assembly of the battery pack 10.

[0069] In this embodiment, an inner wall 223a defining the groove 223 is located on the inside of the housing 200 relative to the seal 240, and an outer wall 223b defining the groove 223 is located on the outside of the housing 200 relative to the seal 240. However, the wall located on the inside of the housing 200 relative to the seal 240 does not have to be the inner wall 223a defining the groove 223, but may be another wall. Similarly, the wall located on the outside of the housing 200 relative to the seal 240 does not have to be the outer wall 223b defining the groove 223, but may be another wall.

[0070] This specification discloses the following embodiments: A.1 A battery pack comprising: a battery cell; and a housing for housing the battery cell, wherein the housing has a seal including a plurality of parts extending diagonally from each other, and walls located on both sides of the seal, the walls being arranged substantially parallel to the plurality of parts of the seal. A.2 The battery pack according to A.1, wherein the housing has a plurality of structures including a plurality of parts of the walls being arranged substantially parallel to the plurality of parts of the seal, the plurality of structures being joined to each other. A.3 The battery pack according to A.2, wherein the weld marks located at the joints of the plurality of structures and overlapping with the seal are at least partially smoothed. A.4 The battery pack according to any one of A.1 to A.3, wherein the housing has a side surface located outside the housing relative to the seal, and the side surface of the housing and the seal are arranged at least partially substantially parallel to each other. B. 1. A battery pack comprising: a battery cell; and a housing for housing the battery cell, wherein the housing has a plurality of structures welded to each other; and a seal that at least partially overlaps with the weld marks formed at the locations where the plurality of structures are welded to each other, and the portion of the weld marks that overlaps with the seal is at least partially smoothed. B. 2. The battery pack according to B. 1, wherein the weld marks include a portion that is raised above the smoothed portion of the weld marks. B. 3. The battery pack according to B. 2, wherein the seal has a shape that at least partially avoids the raised portion. B. 4. The battery pack according to B. 3, wherein the shape of the seal is formed by a notch in the seal. B. 5. The battery pack according to B. 3, wherein the shape of the seal is formed by a thin-walled portion of the seal.

[0071] This application claims priority based on Japanese Patent Application No. 2025-019215, filed on 7 February 2025, Japanese Patent Application No. 2025-019216, filed on 7 February 2025, and Japanese Patent Application No. 2026-015434, filed on 2 February 2026, and incorporates all of its disclosures herein.

[0072] 10 Battery pack, 100 Battery cell, 200 Housing, 202 Housing space, 210 Lower plate, 220 Side frame, 220a First structure, 220b Second structure, 220c Third structure, 220d Fourth structure, 220e Fifth structure, 220f Sixth structure, 221a First weld mark, 221b Second weld mark, 221c Third weld mark, 222 Side upper plate, 223 Groove, 223a Inner wall, 223b Outer wall, 223c Corner section, 224a Inner side wall, 224b Outer side wall, 225 Hollow space, 230 Upper plate, 232 Raised section, 234 Extended section, 240 Seal, 240a First extended section, 240b Second extended section, 240c Third extended portion, 240d Fourth extended portion, 240e Bent portion, 240f Diagonal extended portion, 241 Opening, 242 Projection, 243 Notch, 250 Rivet nut, 252 Nut shaft, 253 Wide portion, 254 Nut head, 260 Bolt, 262 Bolt shaft, 264 Bolt head

Claims

1. A battery pack comprising: a battery cell; and a housing for housing the battery cell, wherein the housing has a seal including a plurality of parts extending diagonally from each other, and walls located on both sides of the seal, the walls being arranged substantially parallel to the plurality of parts of the seal.

2. The battery pack according to claim 1, wherein the housing has a side frame, the side frame includes a plurality of structures welded to each other, the plurality of structures include a portion of the wall, and the portion of the wall of the plurality of structures is arranged substantially parallel to the plurality of portions of the seal and connected to each other.

3. The battery pack according to claim 2, wherein the weld marks located at the points where the side frame and the structure are welded to each other and overlap with the seal are at least partially smoothed.

4. The battery pack according to any one of claims 1 to 3, wherein the housing has a side surface located on the outside of the housing with respect to the seal, and the side surface of the housing and the seal are arranged at least partially substantially parallel to each other.

5. A battery pack comprising: a battery cell; and a housing for housing the battery cell, wherein the housing has a plurality of structures welded to each other; and a seal that at least partially overlaps with the weld marks formed at the locations where the plurality of structures are welded to each other, and the portion of the weld marks that overlaps with the seal is at least partially smoothed.

6. The battery pack according to claim 5, wherein the weld mark includes a portion that is raised above the smoothed portion of the weld mark.

7. The battery pack according to claim 6, wherein the seal has a shape that at least partially avoids the raised portion.

8. The battery pack according to claim 7, wherein the shape of the seal is formed by a notch in the seal.

9. The battery pack according to claim 7, wherein the shape of the seal is formed by the thin-walled portion of the seal.

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