Battery pack

Abstract

To facilitate placement of a seal in the appropriate position during assembly of a battery pack. [Solution] The battery pack (10) includes a battery cell (100) and a housing (200) that houses the battery cell (100). The housing (200) has a side frame (220), an upper plate (230), and a seal (240) arranged between the side frame (220) and the upper plate (230). The side frame (220) includes an inner wall (223a) located inside the housing (200) with respect to the seal (240), and an outer wall (223b) located outside the housing (200) with respect to the seal (240). The seal (240) includes a protrusion (242) that protrudes toward the inner wall (223a) from an edge of the seal (240) facing the side where the inner wall (223a) is located, and another protrusion (242) that protrudes toward the outer wall (223b) from an edge of the seal (240) facing the side where the outer wall (223b) is located.

Description

[Technical Field]

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

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

[0003] Patent Document 1 describes a battery pack. The battery pack includes battery cells and a sealed case that houses the battery cells. The sealed case has a case body with an opening, a lid member that closes the opening, and a sealant positioned between the case body and the lid member.

[0004] Patent Document 2 describes a battery case for vehicles. The case includes a tray on which a battery is placed, a cover that covers the tray, and a sealing member that is positioned between the tray and the cover. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-28907 [Patent Document 2] Japanese Patent Application Laid-Open No. 2011-194982 Summary of the Invention [Problem to be solved by the invention]

[0006] In a battery pack, a seal may be disposed between multiple structural parts of the housing, and it is desirable that the seal be easily disposed in an appropriate position during assembly of the battery pack.

[0007] One object of the present invention is to facilitate proper placement of a seal during assembly of a battery pack. Other objects of the present invention will become apparent from the description herein. [Means for solving the problem]

[0008] One aspect of the present invention is as follows. 1. A battery cell; a housing that houses the battery cell; Equipped with the housing has a plurality of structural portions and a seal disposed between the plurality of structural portions; the plurality of structural portions include a wall located on at least one of an inner side and an outer side of the housing relative to the seal; The seal has a protrusion that protrudes from an edge of the seal facing the wall toward the wall. 2. The battery pack according to claim 1, wherein the housing further has fasteners that fasten the plurality of structural parts together. 3. The battery pack according to claim 2, wherein the seal defines an opening through which the fastener passes. 4. The battery pack according to claim 3, wherein the protrusion is located around the opening. 5. A battery pack according to claim 3 or 4, wherein the protrusion is positioned perpendicular to the edge of the seal and offset from a plane including the center of the fastener. [Effects of the Invention]

[0009] According to the above aspect of the present invention, it is possible to easily place the seal at an appropriate position during assembly of the battery pack. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a perspective view of a battery pack according to an embodiment. [Figure 2] FIG. 2 is a top view of the battery pack according to the embodiment, with the upper plate being transparent. [Figure 3] FIG. 3 is an enlarged view of an area α shown in FIG. [Figure 4] FIG. 4 is a cross-sectional view taken along line AA in FIG. [Figure 5]FIG. 3 is an enlarged view of a region β shown in FIG. 2. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings, similar components are designated by similar reference numerals, and the description thereof will be omitted as appropriate.

[0012] FIG. 1 is a perspective view of a battery pack 10 according to an embodiment. FIG. 2 is a top view of the battery pack 10 according to an embodiment with the upper plate 230 transparently displayed. FIG. 3 is an enlarged view of an area α shown in FIG. 2. FIG. 4 is a cross-sectional view taken along line AA in FIG. 3. FIG. 5 is an enlarged view of an area β shown in FIG. 2. A protrusion 242, which will be described later with reference to FIGS. 3 and 5, is omitted in FIG. 2, 3, and 5. The upper plate 230 is displayed transparently in FIGS. 2, 3, and 5 so that portions of the battery pack 10 hidden by the upper plate 230 can be seen. Thus, in FIGS. 2, 3, and 5, it appears as if the upper plate 230 shown in FIGS. 1 and 4 has been removed.

[0013] In the embodiment, the battery pack 10 is mounted on an automobile. Specifically, the battery pack 10 is mounted between the front and rear wheels of the automobile. Unless otherwise specified, the following description will be given assuming that the battery pack 10 is mounted on an automobile. However, the battery pack 10 can also be used for purposes other than automobiles.

[0014] For the purpose of explanation, the X, Y, and Z directions are shown in each figure. The X direction indicates the front-to-rear 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 a direction 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 arrows pointing to the Y direction, and the arrows pointing to the Z direction indicate the front, left, and up directions of the battery pack 10, respectively. In Figures 2, 3, and 5, a 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, a 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-rear, left-to-right, and up-to-down directions of the battery pack 10 is not limited to this example.

[0015] In the embodiment, the front-rear direction, left-right direction, and up-down direction of the battery pack 10 are determined by the vehicle in which the battery pack 10 is mounted. The X direction, Y direction, and Z direction respectively indicate the front-rear direction, left-right direction, and up-down direction of the vehicle. The arrow pointing to the X direction, the arrow pointing to the Y direction, and the arrow pointing to the Z direction respectively indicate the front, left, and up directions of the vehicle. However, the relationship between the front-rear direction, left-right direction, and up-down direction of the battery pack 10 and the front-rear direction, left-right, and up-down directions of the vehicle is not limited to this example.

[0016] Hereinafter, as necessary, the side indicated by the arrow indicating the X direction will be referred to as the +X side, and the side opposite the side indicated by the arrow indicating the X direction will be referred to as the -X side. Hereinafter, as necessary, the side indicated by the arrow indicating the Y direction will be referred to as the +Y side, and the side opposite the side indicated by the arrow indicating the Y direction will be referred to as the -Y side. Hereinafter, as necessary, the side indicated by the arrow indicating the Z direction will be referred to as the +Z side, and the side opposite the side indicated by the arrow indicating the Z direction will be referred to as the -Z side. Hereinafter, unless otherwise specified, the horizontal direction refers to the direction perpendicular to the Z direction.

[0017] 1 and 2, the battery pack 10 includes a plurality of battery cells 100 and a housing 200. As shown in Fig. 2, the housing 200 forms an accommodation space 202 that accommodates the plurality of battery cells 100.

[0018] 2, the battery pack 10 includes a plurality of battery cells 100 housed in a front portion on the +X side of the accommodation space 202, and a plurality of other battery cells 100 housed in a rear portion on the -X side of the accommodation space 202. Hereinafter, unless otherwise specified, the "front-side plurality of battery cells 100" refers to the plurality of battery cells 100 housed in the front portion on the +X side of the accommodation space 202, and the "rear-side plurality of battery cells 100" refers to the plurality of other battery cells 100 housed in the rear portion on the -X side of the accommodation space 202.

[0019] In the example shown in FIG. 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 smaller than the dimension in the X direction and larger than the dimension in the Y direction. The shape of each battery cell 100 is not limited to the example shown in FIG. 2 . As shown in FIG. 2 , the multiple battery cells 100 on the front side are stacked in the Y direction and electrically connected to each other in series, parallel, or a combination of series and parallel. As shown in FIG. 2 , the multiple battery cells 100 on the rear side are stacked in the Y direction and 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 FIG. 2 . For example, the multiple battery cells 100 may be stacked in the X direction. Furthermore, in addition to the multiple battery cells 100 on the front side and the multiple battery cells 100 on the rear side, multiple other battery cells 100 may be housed.

[0020] The front-side battery cells 100 may be accommodated in a housing (not shown) prepared separately from the housing 200 and housed in the front part of the +X side of the accommodation space 202. Alternatively, the front-side battery cells 100 may be housed directly in the front part of the +X side of the accommodation space 202 without being housed in a housing prepared separately from the housing 200. The same applies to the rear-side battery cells 100.

[0021] 1 and 2, the housing 200 has a lower plate 210, side frames 220, an upper plate 230, and a seal 240. The lower plate 210 and the side frames 220 are sometimes collectively referred to as a lower case. The upper plate 230 is sometimes referred to as an upper case.

[0022] The lower plate 210 is disposed approximately perpendicular to the Z direction. The multiple battery cells 100 are located on the +Z side of the +Z side surface of the lower plate 210. As shown in Fig. 2, the lower plate 210 has a generally rectangular shape with a pair of sides approximately parallel to the X direction and another pair of sides approximately parallel to the Y direction. The shape of the lower plate 210 is not limited to the example shown in Fig. 2.

[0023] The side frame 220 extends toward the +Z side from the entire periphery of the +Z side surface of the lower plate 210. As shown in Fig. 2, the side frame 220 extends to surround the entire storage space 202 when viewed from the Z direction. Unless otherwise specified, hereinafter, the inside of the housing 200 refers to the side on which the storage space 202 is located with respect to the side frame 220 when viewed from the Z direction, and the outside of the housing 200 refers to the side opposite to the side on which the storage space 202 is located with respect to the side frame 220 when viewed from the Z direction.

[0024] As shown in FIG. 4, the side frame 220 includes an upper side plate 222, an inner side wall 224a, and an outer side wall 224b.

[0025] 4, the side upper plate 222 is disposed approximately perpendicular to the Z direction. An inner wall 223a and an outer wall 223b protrude from the upper surface on the +Z side of the side upper plate 222. 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.

[0026] As shown in FIG. 4, a groove 223 is defined by the upper surface of the side upper plate 222 on the +Z side and the opposing side surfaces of the inner wall 223a and the outer wall 223b. As shown in FIG. 4, the groove 223 opens upward on the +Z side. As shown in FIG. 2, the groove 223 extends to surround the entire accommodation space 202 as viewed from the Z direction. Unless otherwise specified, the inner edge of the groove 223 refers to the edge of the groove 223 located on the inside of the housing 200 as viewed from the Z direction, and the outer edge of the groove 223 refers to the edge of the groove 223 located on the outside of the housing 200 as viewed from the Z direction. The inner edge of the groove 223 corresponds to the side surface of the inner wall 223a located on the outside of the housing 200 as viewed from the Z direction. The outer edge of the groove 223 corresponds to the side surface of the outer wall 223b located on the inside of the housing 200 as viewed from the Z direction. Hereinafter, 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.

[0027] As shown in Fig. 4, the inner side wall 224a extends toward the -Z side from an end of the side upper plate 222 located inside the housing 200. As shown in Fig. 4, the outer side wall 224b extends toward the -Z side from an end of the side upper plate 222 located outside the housing 200. As shown in Fig. 4, inside the side frame 220, a hollow space 225 is defined by the lower surface on the -Z side of the side upper plate 222 and the opposing side surfaces of the inner side wall 224a and the outer side wall 224b.

[0028] 1, the upper plate 230 is located on the +Z side with respect to the side frame 220. The upper plate 230 includes a raised portion 232 and an extending portion 234. The raised portion 232 is raised upward on the +Z side with respect to the lower plate 210 and the side frame 220. The extending portion 234 extends horizontally from the lower end of the raised portion 232 on the +Z side toward the outside of the raised portion 232 in a direction approximately perpendicular to the Z direction.

[0029] The seal 240 is an elastic body such as rubber or elastomer. As shown in FIG. 4, the seal 240 is disposed in the groove 223. As shown in FIG. 2, the seal 240 extends to surround the entire accommodating space 202, similar to the groove 223. Hereinafter, unless otherwise specified, the inner edge of the seal 240 refers to the edge of the seal 240 facing the inside of the housing 200 as viewed from the Z direction, and the outer edge of the seal 240 refers to the edge of the seal 240 facing the outside of the housing 200 as viewed from the Z direction. Hereinafter, unless otherwise specified, the width of the seal 240 refers to the width of the seal 240 in the direction from the inner edge of the seal 240 to the outer edge of the seal 240 as viewed from the Z direction.

[0030] The side frame 220, the upper plate 230, and the seal 240 will be described in detail with reference to FIGS.

[0031] As shown in FIG. 4 , the side upper plate 222 and the extension portion 234 are fastened to each other by fasteners including a rivet nut 250 and a bolt 260, with the seal 240 disposed between the side upper plate 222 and the extension portion 234. As shown in FIGS. 3 and 4 , the seal 240 is positioned between the side upper plate 222 and the extension portion 234, with the inner wall 223a positioned inside the housing 200 with respect to the seal 240, and the outer wall 223b positioned outside the housing 200 with respect 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 FIG. 4 , the seal 240 defines an opening 240a through which the fasteners including the rivet nut 250 and the bolt 260 pass in the Z direction. The housing 200 defines an accommodation space 202 by fastening the side upper plate 222 and the extension portion 234 to each other. The seal 240 is compressed in the Z direction by the side upper plate 222 and the extension portion 234 in a state in which the side upper plate 222 and the extension portion 234 are fastened to each other by the rivet nuts 250 and the bolts 260. By compressing the seal 240 in the Z direction, the area between the side upper plate 222 and the extension portion 234 can be sealed.

[0032] As shown in FIG. 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 the lower end of the nut shaft 252 on the -Z side positioned within a hollow space 255. The nut shaft 252 includes a wide portion 253 located on the -Z side of the -Z side surface of the side upper plate 222. The wide portion 253 is formed by deformation of the nut shaft 252 outward in the horizontal direction. The horizontal diameter of the wide portion 253 is larger than the horizontal diameters of both sides of the wide portion 253 of the nut shaft 252 in the Z direction. The nut head 254 is provided at the upper end of the +Z side of the nut shaft 252. The nut head 254 is located on the +Z side of the +Z side surface of the side upper plate 222 and is located within the opening 240a 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 sandwiching the side upper plate 222 in the Z direction.

[0033] As shown in FIG. 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 the nut head 254 in the Z direction. In the example shown in FIG. 4 , even if it is difficult to provide a screw hole in the side upper plate 222 for screwing the bolt 260 because the thickness of the side upper plate 222 in the Z direction is relatively thin, the bolt 260 can be screwed into the rivet nut 250 provided in the side upper plate 222. The bolt head 264 is located on the +Z side with respect to the +Z side surface of the extension portion 234. With the rivet nut 250 and the bolt 260 screwed together, the side upper plate 222 and the extension portion 234 are fastened together.

[0034] The fastening of the side upper plate 222 and the extension portion 234 is not limited to the example shown in Fig. 4. For example, the bolt 260 may be screwed into a threaded hole provided in the side upper plate 222 without the rivet nut 250 being provided on the side upper plate 222.

[0035] As shown in FIG. 3 , multiple protrusions 242 are provided on the inner edge and outer edge of the seal 240 around the opening 240a in region α as viewed from the Z direction. As shown in FIG. 2 , region α is a portion of the side frame 220 located on the +Y side with respect to the accommodation space 202. As shown in FIG. 3 , around the opening 240a in region α, the seal 240 has two protrusions 242 protruding from the inner edge of the seal 240 toward the inner wall 223a and two other protrusions 242 protruding from the outer edge of the seal 240 toward the outer wall 223b. In the example shown in FIG. 3 , each protrusion 242 is positioned offset from a plane perpendicular to the inner edge or outer edge of the seal 240 as viewed from the Z direction and including the center of the bolt head 264. In the example shown in FIG. 3 , line AA corresponds to a plane perpendicular to the inner edge or outer edge of the seal 240 as viewed from the Z direction and including the center of the bolt head 264. As shown in Figure 3, in region α, on the -X side of line AA, there are two protrusions 242 that protrude away from the inner edge of seal 240 and the outer edge of seal 240, and on the +X side of line AA, there are other two protrusions 242 that protrude away from the inner edge of seal 240 and the outer edge of seal 240.

[0036] 3, the Y-direction width WT of groove 223 is substantially constant regardless of the position in the X-direction of groove 223. In region α shown in Fig. 3, the Y-direction width WS1 of seal 240 between two protrusions 242 provided on the -X side of line AA and the Y-direction width WS2 of seal 240 between two other protrusions 242 provided on the +X side of line AA are wider than the Y-direction width WS of seal 240 in other parts of seal 240 and are less than the Y-direction width WT of groove 223.

[0037] In the example shown in FIGS. 3 and 4 , the width of the seal 240 can be partially adjusted to approximate the width WT of the groove 223 by the protrusion 242. Therefore, horizontal displacement of the seal 240 within the groove 223 can be suppressed compared to when the protrusion 242 is not provided and the width of the seal 240 is equal to the width WS shown in FIG. 3 throughout the entire seal 240. If displacement of the seal 240 occurs, the side upper plate 222 and the extension portion 234 may be fastened to each other by the rivet nut 250 and the bolt 260 in a state where a portion of the seal 240 is wedged between the −Z side surface of the extension portion 234 and the +Z side surface of the nut head 254. Weakness of a portion of the seal 240 between the −Z side surface of the extension portion 234 and the +Z side surface of the nut head 254 may undesirably affect the sealing of the seal 240. 3 and 4, suppressing displacement of seal 240 can prevent a portion of seal 240 from getting between the -Z side surface of extension portion 234 and the +Z side surface of nut head 254. Therefore, in the example shown in Figures 3 and 4, it is possible to more easily arrange seal 240 in an appropriate position during assembly of battery pack 10, compared to when seal 240 does not have protrusion 242.

[0038] 3 and 4, the width of the seal 240 does not need to be close to the width WT of the groove 223 throughout the entire seal 240. Therefore, the precision required for positioning the seal 240 in the groove 223 can be reduced compared to when the width of the seal 240 is equal to the width WS1 or the width WS2 shown in FIG. 3 throughout the entire seal 240. Therefore, the seal 240 can be more easily positioned in an appropriate position during assembly of the battery pack 10 compared to when the width of the seal 240 is equal to the width WS1 or the width WS2 shown in FIG. 3 throughout the entire seal 240. Furthermore, compared to when the width of the seal 240 is equal to the width WS1 or the width WS2 shown in FIG. 3 throughout the entire seal 240, horizontal inward expansion of the seal 240 when the seal 240 is compressed in the Z direction by the side upper plate 222 and the extension 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 entering between the -Z side surface of the extension portion 234 and the +Z side surface of the nut head 254.

[0039] 3 and 4, it is not necessary to provide the protrusions 242 on both sides in the Y direction of the center of the bolt head 264 when viewed from the Z direction. Therefore, compared to a case where the protrusions 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 extension portion 234 and the seal 240 near the protrusions 242 spreads horizontally inward, it is possible to prevent a portion of the seal 240 from getting between the -Z side surface of the extension portion 234 and the +Z side surface of the nut head 254.

[0040] 3 and 4 can also be applied to other regions of the side frame 220. For example, as shown in Fig. 5, the configuration of region α can also be applied to region β located at a corner on the +X and +Y sides with respect to the storage space 202 of the side frame 220. In region β shown in Fig. 5, four protrusions 242 are provided on the inner edge and outer edge of the seal 240 around an opening 240a located on the -X side with respect to the corner when viewed from the Z direction.

[0041] Although the embodiments of the present invention have been described above with reference to the drawings, these are merely examples of the present invention, and various other configurations can also be adopted.

[0042] In the embodiment, the sealing of the region between the side upper plate 222 and the extension portion 234 using the seal 240 has been described. The sealing described using the embodiment can be applied to sealing the region between multiple structural portions of the housing 200, including the sealing of the region between the side upper plate 222 and the extension portion 234.

[0043] In the embodiment, the protrusions 242 of the seal 240 are provided on both the inner edge and the outer edge of the seal 240. However, the protrusions 242 of the seal 240 may be provided on only one of the inner edge and the outer edge of the seal 240. Even when the protrusions 242 are provided on only one of the inner edge and the outer edge of the seal 240, the width of the seal 240 can be made partially close to the width of the groove 223. Therefore, as described in the embodiment, it is possible to easily place the seal 240 in an appropriate position during assembly of the battery pack 10.

[0044] In the embodiment, an inner wall 223a defining groove 223 is located inside housing 200 relative to seal 240, and an outer wall 223b defining groove 223 is located outside housing 200 relative to seal 240. However, the wall located inside housing 200 relative to seal 240 does not have to be inner wall 223a defining groove 223, but may be another wall. Similarly, the wall located outside housing 200 relative to seal 240 does not have to be outer wall 223b defining groove 223, but may be another wall. [Explanation of symbols]

[0045] 10 battery pack, 100 battery cell, 200 housing, 202 storage space, 210 lower plate, 220 side frame, 222 side upper plate, 223 groove, 223a inner wall, 223b outer wall, 224a inner side wall, 224b outer side wall, 225 hollow space, 230 upper plate, 232 raised portion, 234 extension portion, 240 seal, 240a opening, 242 protrusion, 250 rivet nut, 252 nut shaft, 253 wide portion, 254 nut head, 255 hollow space, 260 bolt, 262 bolt shaft, 264 bolt head

Claims

1. A battery cell; a housing that houses the battery cell; Equipped with the housing has a plurality of structural portions and a seal disposed between the plurality of structural portions; the plurality of structural portions include a wall located on at least one of an inner side and an outer side of the housing relative to the seal; The seal has a protrusion that protrudes from an edge of the seal facing the wall toward the wall.

2. The battery pack according to claim 1 , wherein the housing further includes fasteners that fasten the plurality of structural portions together.

3. The battery pack of claim 2 , wherein the seal defines an opening through which the fastener passes.

4. The battery pack according to claim 3 , wherein the protrusion is located around the periphery of the opening.

5. The battery pack according to claim 3 or 4, wherein the protrusion is positioned offset with respect to a plane that is perpendicular to the edge of the seal and that includes a center of the fastener.

Images