Battery pack

Abstract

A battery module (10) comprises a battery cell (100) and an enclosure (200) accommodating the battery cell (100). The enclosure (200) has a side frame (220), an upper plate (230), and a seal (240) disposed between the side frame (220) and the upper plate (230). The side frame (220) includes an inner wall (223a) located on the inner side of the enclosure (200) relative to the seal (240), and an outer wall (223b) located on the outer side of the enclosure (200) relative to the seal (240). The seal (240) includes: a protrusion (242) protruding toward the inner wall (223a) from an edge of the seal (240) facing the side on which the inner wall (223a) is located; and a protrusion (242) protruding toward the outer wall (223b) from an edge of the seal (240) facing the side on which the outer wall (223b) is located.

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 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 a vehicle. 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.

[0005] JP 2015-28907 A JP 2011-194982 A

[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.

[0008] One aspect of the present invention is as follows: 1. A battery pack comprising: a battery cell; and a housing that houses the battery cell, wherein the housing has a plurality of structural parts and a seal arranged between the plurality of structural parts, wherein the plurality of structural parts include walls located on at least one of the inside and outside of the housing relative to the seal, and the seal has a protrusion that protrudes from an edge of the seal facing the side where the wall is located toward the wall. 2. The battery pack described in 1., wherein the housing further has a fastener that fastens the plurality of structural parts to each other. 3. The battery pack described in 2., wherein the seal defines an opening through which the fastener passes. 4. The battery pack described in 3., wherein the protrusion is located around the opening. 5. The battery pack described in 3. or 4., wherein the protrusion is positioned offset with respect to a plane that is perpendicular to the edge of the seal and includes the center of the fastener.

[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.

[0010] 3 is a perspective view of a battery pack according to an embodiment; FIG. 4 is a top view of a battery pack according to an embodiment in a state where an upper plate is transparently displayed; FIG. 5 is an enlarged view of an area α shown in FIG. 2; FIG. 6 is a cross-sectional view taken along line AA in FIG. 3; and FIG. 7 is an enlarged view of an area β shown in FIG. 2.

[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 region α shown in FIG. 2. FIG. 4 is a cross-sectional view taken along line A-A in FIG. 3. FIG. 5 is an enlarged view of region β shown in FIG. 2. In FIG. 2, a protrusion 242, which will be described later with reference to FIGS. 3 and 5, is omitted. In FIGS. 2, 3, and 5, the upper plate 230 is displayed transparently 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 Y direction, and 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 direction, Y direction, and Z direction and the front-to-rear direction, left-to-right direction, and up-to-down direction 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 needed, 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 needed, 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 needed, 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 accommodated in a front portion on the +X side of the accommodation space 202, and a plurality of other battery cells 100 accommodated in a rear portion on the −X side of the accommodation space 202. Hereinafter, unless otherwise specified, the front-side battery cells 100 refer to the plurality of battery cells 100 accommodated in the front portion on the +X side of the accommodation space 202, and the rear-side battery cells 100 refer to the other plurality of battery cells 100 accommodated 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 plurality of 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 plurality of 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 plurality of battery cells 100 is not limited to the example shown in FIG. 2 . For example, the plurality of battery cells 100 may be stacked in the X direction. Furthermore, in addition to the plurality of battery cells 100 on the front side and the plurality of battery cells 100 on the rear side, a plurality of 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 includes 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 substantially 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 substantially rectangular 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 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 accommodation space 202 when viewed from the Z direction. Unless otherwise specified, the inside of the housing 200 refers to the side on which the accommodation 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 accommodation 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 storage space 202 as viewed from the Z direction. Hereinafter, 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 relative 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 relative 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 material 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 storage 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 223 a positioned inside the housing 200 with respect to the seal 240, and the outer wall 223 b 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 223 a and outer wall 223 b, respectively. As shown in FIG. 4 , the seal 240 defines an opening 240 a 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 a rivet nut 250 and a bolt 260. Compressing the seal 240 in the Z direction enables the area between the side upper plate 222 and the extension portion 234 to 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 on 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 threaded 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 , when viewed from the Z direction, multiple protrusions 242 are provided on the inner edge and outer edge of the seal 240 around the opening 240a in region α. ​​As shown in FIG. 2 , region α is a portion of the side frame 220 located on the +Y side of the storage 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 when viewed from the Z direction and including the center of the bolt head 264. In the example shown in FIG. 3 , line A-A corresponds to a plane perpendicular to the inner edge or outer edge of the seal 240 when viewed from the Z direction and including the center of the bolt head 264. As shown in FIG. 3, in region α, on the −X side of line A-A, 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 A-A, 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 approximately constant regardless of the X-direction position 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 A-A and the Y-direction width WS2 of seal 240 between two other protrusions 242 provided on the +X side of line A-A 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 Figures 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 width of the seal 240 is equal to the width WS shown in Figure 3 throughout the entire seal 240 without the protrusion 242. If displacement of the seal 240 were to occur, the side upper plate 222 and the extension 234 may be fastened together by the rivet nut 250 and the bolt 260 with a portion of the seal 240 wedging between the -Z side surface of the extension 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 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 easier to arrange seal 240 in an appropriate position during assembly of battery pack 10 compared to when seal 240 does not have protrusion 242.

[0038] 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 throughout the entire seal 240. Therefore, the precision required for positioning the seal 240 within the groove 223 can be reduced compared to when the width of the seal 240 is equal to the width WS1 or width WS2 shown in Figure 3 throughout the entire seal 240. Therefore, the seal 240 can be more easily positioned appropriately during assembly of the battery pack 10 compared to when the width of the seal 240 is equal to the width WS1 or width WS2 shown in Figure 3 throughout the entire seal 240. Furthermore, compared to when the width of the seal 240 is equal to the width WS1 or width WS2 shown in Figure 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 inward in the horizontal direction, 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, which is located at a corner on the +X and +Y sides of 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 of 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 position the seal 240 in an appropriate position during assembly of the battery pack 10.

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

[0045] This application claims priority based on Japanese Patent Application No. 2024-146444, filed on August 28, 2024, the disclosure of which is incorporated herein in its entirety by reference.

[0046] 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 pack comprising: a battery cell; and a housing that houses the battery cell; wherein the housing has a plurality of structural parts and a seal disposed between the plurality of structural parts; the plurality of structural parts includes a wall located on at least one of the inside and outside of the housing relative to the seal; and the seal has a protrusion that protrudes from an edge of the seal facing the side where the wall is located toward the wall.

2. The battery pack according to claim 1, wherein the housing further has fasteners for fastening the plurality of structural parts 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 protrusions are 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 perpendicular to the edge of the seal and including the center of the fastener.

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