Power storage device

Abstract

The present invention provides an electric storage device (100), which comprises: a plurality of electric storage cells (21) arranged in an arrangement direction; a housing shell comprising an upper shell (11) and a lower shell (12) and housing the plurality of electric storage cells (21); a bus bar module (30) for electrically connecting the plurality of electric storage cells (21); and a cover (40) arranged between the upper shell (11) and the bus bar module (30) in a manner capable of abutting against a portion of the upper shell (11), wherein the plurality of electric storage cells (21) are fixed to the lower shell (12), the bus bar module (30) comprises a plurality of bus bars (35) for connecting external terminals of the adjacent electric storage cells (21) in the arrangement direction, and the cover (40) comprises a facing portion (41) facing the plurality of bus bars (25), and a protrusion (42) abutting against the bus bars (25) is provided on the facing portion (41).

Description

Technical Field

[0001] The present disclosure relates to a power storage device mounted on a vehicle. Background Art

[0002] Japanese Patent Application Publication No. 2012-084319 discloses a conventional battery module for use in vehicles, in which a busbar module is incorporated into a battery pack (battery stack) composed of multiple batteries arranged side by side. The busbar module includes a busbar and a busbar housing, which is formed by a series of multiple cylindrical enclosures that are open both upward and downward.

[0003] In recent years, there has been a demand for higher capacity in power storage devices containing these modules within a housing. Consequently, the modules housed within the housing have become larger and larger in size. Consequently, external shocks may be applied to the power storage device, for example, a downward shock may be applied to the upper housing. In such cases, if the shock cannot be effectively dispersed within the upper housing, the upper housing may be damaged. Summary of the Invention

[0004] The present disclosure has been made in view of the above-mentioned problems, and an object of the present disclosure is to provide a power storage device capable of suppressing damage to the upper case when an impact is input to the upper case from the outside.

[0005] The power storage device disclosed herein comprises: a plurality of power storage cells, each including an external terminal, arranged in an arrangement direction; a housing shell, including an upper shell and a lower shell, for housing the plurality of power storage cells; a bus bar module for electrically connecting the plurality of power storage cells; and a cover body, which is arranged between the upper shell and the bus bar module in a manner capable of abutting against a portion of the upper shell. The plurality of power storage cells are fixed to the lower shell. The bus bar module includes a plurality of bus bars for connecting the external terminals of the adjacent power storage cells in the arrangement direction. The cover body includes an opposing portion facing the plurality of bus bars. A protrusion abutting against the bus bar is provided on the opposing portion.

[0006] According to the above structure, when a downward impact is applied to the upper housing, a portion of the impact is transmitted to the housing via the portion of the upper housing that abuts the housing. At this time, the protrusions provided on the portion of the housing facing the multiple busbars abut the busbars, causing a portion of the impact to be transmitted to the power storage cells via the protrusions, busbars, and external terminals. Because the power storage cells are fixed to the lower housing, the impact transmitted to the power storage cells is transmitted via the fixing portion to the lower housing. This allows the impact input to the upper housing to be dispersed while being transmitted to the lower housing, thereby preventing damage to the upper housing.

[0007] In the power storage device according to the present disclosure, the bus bar may include a welded portion welded to the external terminal. In this case, the protrusion may be in contact with the bus bar while being separated from the welded portion.

[0008] According to the above structure, the protrusion contacts the bus bar separately from the welded portion, which can prevent the impact from the upper case from being directly input to the welded portion. This can prevent the welded portion from breaking and stably maintain the connection between the bus bar and the external terminal.

[0009] In the power storage device based on the above-mentioned present disclosure, the busbar may include a plate-shaped portion, the plate-shaped portion having a first surface and a second surface that are in a front-to-back relationship with each other, and placed on the external terminal. In this case, the second surface is placed on the external terminal, and the first surface faces the side opposite to the side where the external terminal is located. A recessed portion that is recessed toward the second surface may be provided on the first surface, and the welded portion may be provided at the bottom of the recessed portion. Furthermore, the protrusion may have a planar portion that contacts the first surface. The planar portion may contact the first surface across the recessed portion without contacting the welded portion.

[0010] According to the above structure, the flat portion provided at the front end of the protrusion contacts the first surface of the plate-shaped portion of the busbar, thereby distributing the load input from the protrusion to the busbar in the planar direction. This can suppress deformation of the busbar and reduce the load applied to the external terminal.

[0011] Furthermore, by providing the welded portion in the recessed portion provided on the first surface of the plate-like portion, the welded portion can be formed over a relatively large area. In this case, the flat portion of the protrusion contacts the first surface so as to straddle the recessed portion, thereby forming the welded portion over a large area and suppressing direct impact from the upper housing to the welded portion.

[0012] In the power storage device according to the present disclosure, the protrusion may include a weight-reducing portion.

[0013] According to the above structure, by forming the weight-reducing portion on the protrusion, the shape of the protrusion can be stabilized during manufacturing. This allows the load transmitted from the upper housing to be evenly distributed within the protrusion. Furthermore, by providing the weight-reducing portion, the protrusion's planar profile can be increased compared to a protrusion of the same volume without the weight-reducing portion, thereby distributing the load transmitted from the upper housing.

[0014] In the power storage device according to the present disclosure, the cover includes an upper surface portion facing the side opposite to the side where the bus bar is located and capable of contacting the portion of the upper case. In this case, the upper surface portion may be flat.

[0015] By adopting the above-described structure, the load transmitted from the upper housing to the cover can be distributed more evenly.

[0016] The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when read with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is an exploded perspective view of the power storage device according to the embodiment.

[0018] Figure 2 It is a plan view of the power storage device according to the embodiment.

[0019] Figure 3 It is along Figure 2 A cross-sectional view of the power storage device taken along line III-III is shown.

[0020] Figure 4 It is a perspective cross-sectional view partially showing a cover, a bus bar module, and a plurality of power storage cells included in the power storage device according to the embodiment. DETAILED DESCRIPTION

[0021] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. It should be noted that in the embodiments described below, identical or common parts are denoted by the same reference numerals in the drawings, and their description will not be repeated.

[0022] Figure 1 It is an exploded perspective view of the power storage device according to the embodiment. Figure 2 : is a top view of the power storage device according to the embodiment. Figure 1 as well as Figure 2 The power storage device 100 according to the embodiment will be described.

[0023] The power storage device 100 of the embodiment is mounted on a hybrid vehicle that can run using power from at least one of a motor and an engine, or on an electric vehicle that runs using driving force derived from electrical energy. The power storage device 100 can be mounted under the floor of the vehicle or positioned between the floor and the seats.

[0024] like Figure 1 as well as Figure 2 As shown, the power storage device 100 according to the embodiment includes a housing case 10 , a power storage stack 20 , a bus bar module 30 , and a cover 40 .

[0025] The housing case 10 houses the battery stack 20, busbar module 30, and cover 40. The housing case 10 includes an upper case 11 and a lower case 12. The upper case 11 has a generally box-like shape that opens downward. The lower case 12 has a generally box-like shape that opens upward.

[0026] The power storage stack 20 includes a plurality of power storage cells 21 arranged in a predetermined arrangement direction. The plurality of power storage cells 21 are fixed to the bottom of the lower case 12 by fixing means such as brackets (not shown).

[0027] The power storage cell 21 is a secondary battery such as a nickel-metal hydride battery or a lithium-ion battery. The cell has, for example, a rectangular shape. A secondary battery can use either a liquid electrolyte or a solid electrolyte. Alternatively, the power storage cell can be a unit capacitor configured to store electricity.

[0028] The power storage cell 21 includes a housing 22, a positive electrode terminal 23 and a negative electrode terminal 24 as external terminals, and a battery element 25 (see Figure 3 The housing 22 has a square shape. The positive terminal 23 and the negative terminal 24 are provided on the upper surface portion 22a of the housing 22. It should be noted that the positive terminal 23 and the negative terminal 24 are connected to each other through an insulator 26 (see Figure 3 ) and is insulated from the housing 22.

[0029] A battery element 25 is housed within the housing 22. The positive electrode terminal 23 is connected to the positive electrode of the battery element 25 via a conductive member (not shown). The negative electrode terminal 24 is connected to the negative electrode of the battery element 25 via a conductive member (not shown).

[0030] The plurality of power storage cells 21 are arranged such that their largest side surfaces face each other. The plurality of power storage cells 21 are arranged such that their positive electrode terminals 23 and negative electrode terminals 24 are alternately arranged in parallel in the arrangement direction.

[0031] The busbar module 30 is a module used to electrically connect the multiple power storage cells 21. The busbar module 30 is positioned above the power storage stack 20. The busbar module 30 is positioned at both ends of the width of the power storage cells 21, which is perpendicular to the arrangement direction. The busbar module 30 includes a busbar holder 31 and multiple busbars 35.

[0032] The bus bar holder 31 holds a plurality of bus bars 35. The bus bar holder 31 is provided with a plurality of bus bar accommodating portions 32 that are continuous in the arrangement direction. The bus bar holder 31 is made of an insulating resin member.

[0033] The plurality of bus bars 35 connect the external terminals of the adjacent power storage cells 21 in the arrangement direction. Specifically, the plurality of bus bars 35 connect the positive electrode terminals 23 and the negative electrode terminals 24 adjacent to each other in the arrangement direction at each end in the width direction. This connects the plurality of power storage cells 21 in series.

[0034] The bus bar 35 is made of a metal member and is connected to the positive electrode terminal 23 and the negative electrode terminal 24 by welding. In other words, the bus bar 35 has a welded portion 36 welded to the positive electrode terminal 23 and the negative electrode terminal 24.

[0035] The cover 40 is disposed between the upper case 11 and the bus bar module 30 so as to be in contact with a portion of the upper case 11. The cover 40 is provided so as to cover the bus bar holder 31. The cover 40 is provided so as to extend in the arrangement direction and is formed of a resin member.

[0036] Figure 3 It is along Figure 2 A cross-sectional view of the power storage device taken along line III-III is shown. Figure 4 This is a perspective cross-sectional view partially showing a cover, a bus bar module, and a plurality of power storage cells included in the power storage device according to the embodiment. Figure 3 as well as Figure 4 The cover 40 , the bus bar module 30 , the power storage cells 21 , and the like will be described in detail.

[0037] It should be noted that, for ease of understanding, Figure 3 、 Figure 4 Only one side in the width direction of the power storage cell 21 is shown. On the other side in the width direction of the power storage cell 21, the structures of the cover 40, bus bar module 30, and power storage cell 21 are substantially the same as those on the one side in the width direction, so the structure of the one side in the width direction will be described here.

[0038] The busbar housing portion 32 of the busbar holder 31 is configured in a generally box-like shape. The busbar housing portion 32 includes a bottom portion 33 and a peripheral wall portion 34. The bottom portion 33 is provided with an opening 33a. The peripheral wall portion 34 is provided so as to rise from the peripheral edge of the bottom portion 33. A portion of the peripheral edge of a busbar 35 is placed on the bottom portion 33. Claws 331 are provided on the inner wall of the peripheral wall portion 34. The claws 331 engage with a portion of the peripheral edge of the busbar 35 placed on the bottom portion 33.

[0039] The positive electrode terminal 23 and the negative electrode terminal 24 have a substantially flat plate shape and are disposed in the opening 33a of the bus bar housing 32. The positive electrode terminal 23 and the negative electrode terminal 24 are insulated from the housing 22 by an insulator 26.

[0040] The bus bar 35 includes a first plate-shaped portion 351 and a second plate-shaped portion 352, which serve as plate-shaped portions, and a connecting portion 353. The first plate-shaped portion 351 forms the first end of the bus bar 35, located on one side in the arrangement direction. The second plate-shaped portion 352 forms the second end of the bus bar 35, located on the other side in the arrangement direction. The connecting portion 353 connects the first plate-shaped portion 351 and the second plate-shaped portion 352. The connecting portion 353 is provided so as to protrude upward.

[0041] On one side in the width direction of the power storage cell 21 , the first plate-shaped portion 351 is placed on the positive electrode terminal 23 , and the second plate-shaped portion 352 is placed on the negative electrode terminal 24 .

[0042] The first plate-shaped portion 351 has a first surface 351a and a second surface 351b that are opposite to each other. The first surface 351a faces the side opposite to the positive electrode terminal 23 , while the second surface 351b is placed on the positive electrode terminal 23 .

[0043] The first surface 351 a is provided with a recessed portion 37 that is recessed toward the second surface 351 b . The bottom of the recessed portion 37 is provided with a welded portion 36 that is welded to the positive electrode terminal 23 .

[0044] Similarly, the second plate-shaped portion 352 has a first surface 352a and a second surface 352b that are opposite each other. The first surface 352a faces the side opposite to the negative electrode terminal 24. The second surface 351b is placed on the negative electrode terminal 24. It should be noted that the first surface 352a and the first surface 351a are coplanar, and the second surface 352b and the second surface 351b are coplanar.

[0045] The first surface 352a is provided with a recessed portion 37 that is recessed toward the second surface 352b. The bottom of the recessed portion 37 is provided with a welded portion 36 that is welded to the negative electrode terminal 24.

[0046] The upper housing 11 has a downwardly projecting convex portion 11c on its inner surface. The convex portion 11c functions as a load transmitting portion that transmits a load to the cover 40 when a downward impact is input to the upper housing 11. The bottom surface of the convex portion 11c is formed flat.

[0047] The cover 40 has an upper surface portion 40a. The upper surface portion 40a faces the side opposite to the side where the busbar 35 is located. In other words, the upper surface portion 40a faces upward. The upper surface portion 40a is capable of abutting against the aforementioned protrusion 11c, which is part of the upper housing 11. Specifically, the aforementioned protrusion 11c can be arranged to always abut against the upper surface portion 40a, or when an impact is input downward to the upper housing 11, the protrusion 11c can be caused to abut against the upper surface portion 40a by pressing the upper housing 11 downward.

[0048] The upper surface portion 40 a is provided flatly. Thus, when a downward impact is input to the upper housing 11 , the load input to the upper surface portion 40 a via the convex portion 11 c can be evenly distributed to the cover 40 .

[0049] The cover 40 includes a facing portion 41. The facing portion 41 is arranged to extend in the aforementioned arrangement direction. The facing portion 41 is located above the plurality of bus bars 35 and faces the plurality of bus bars 35. The facing portion 41 is provided with a plurality of protrusions 42. The plurality of protrusions 42 are respectively provided at positions corresponding to the external terminals of the power storage cells 21. The plurality of protrusions 42 are each arranged to protrude downward.

[0050] The protrusion 42 is provided so as to abut against the bus bar 35. Specifically, the protrusion 42 abuts against the plate-shaped portion of the bus bar 35. More specifically, the protrusion 42 abuts against one of the first plate-shaped portion 351 and the second plate-shaped portion 352.

[0051] Furthermore, the protrusion 42 contacts the bus bar 35 at a distance from the welded portion 36. Therefore, when a downward impact is applied to the upper housing 11 as described above, the impact is prevented from being directly applied to the welded portion 36 via the protrusion 42. This prevents the welded portion 36 from breaking, and stably maintains the connection between the bus bar 35 and the external terminal.

[0052] The protrusion 42 has a roughly block shape. The protrusion 42 has a weight-reducing portion 42c. The cover body 40 including the protrusion 42 is integrally formed of a resin component by, for example, injection molding. When manufacturing the cover body 40, the shape of the protrusion 42 can be stabilized by providing the weight-reducing portion 42c. As a result, the load transmitted from the upper shell 11 can be evenly distributed within the protrusion 42. In addition, by providing the weight-reducing portion 42c, the outer shape of the protrusion 42 in the planar direction can be increased compared to the case where the protrusion 42 is formed with the same volume without providing the weight-reducing portion 42c, and the load transmitted from the upper shell 11 can be sufficiently dispersed.

[0053] The protrusion 42 has a flat surface 42a that abuts the first surface of the plate-shaped portion. Specifically, when the protrusion 42 abuts the first plate-shaped portion 351, the flat surface 42a abuts the first surface 351a. When the protrusion 42 abuts the second plate-shaped portion 352, the flat surface 42a abuts the first surface 352a.

[0054] Here, the flat surface 42a contacts the first surface across the recess 37 without contacting the welded portion 36. Therefore, the load input from the protrusion 42 to the bus bar 35 can be dispersed in the planar direction. This suppresses deformation of the bus bar 35 and reduces the load applied to the external terminals. Furthermore, by having the flat surface 42a span the recess 37, the welded portion 36 can be formed over a wide area.

[0055] As described above, the power storage device 100 of the embodiment has the following structure: the cover 40 is arranged between the bus bar module 30 and the upper case 11 in a manner that can abut against a portion of the upper case 11, and the facing portion 41 of the cover 40 facing the plurality of bus bars 35 is provided with a protrusion 42 that abuts against the bus bars 35.

[0056] Thus, when a downward impact is applied to the upper shell 11, a portion of the impact is transmitted to the cover body via a portion of the upper shell 11 (specifically, the convex portion 11c) that abuts the cover body 40. At this time, the protrusion 42 provided on the facing portion 41 of the cover body 40 abuts the bus bar 35, thereby enabling a portion of the impact to be transmitted to the power storage cell 21 via the protrusion 42, the bus bar 35, and the external terminal. As described above, since the power storage cell 21 is fixed to the lower shell 12, the impact transmitted to the power storage cell 21 is transmitted via the fixing portion to the lower shell 12. In this way, the impact input to the upper shell 11 can be dispersed while being transmitted to the lower shell 12. As a result, damage to the upper shell 11 can be suppressed.

[0057] (Other Modifications)

[0058] In the above embodiment, the bus bar 35 is provided with a recess 37 and a welded portion 36 at the bottom of the recess 37. However, the recess 37 may be omitted and the welded portion 36 may be provided at another location. In this case, the protrusion 42 (more specifically, the flat surface 42a) abuts against the bus bar 35 at a position that does not overlap with the welded portion 36 in the vertical direction, while being spaced apart from the welded portion 36.

[0059] In addition, although the first plate-shaped portion 351 and the second plate-shaped portion 352 of the bus bar 35 are connected by the upwardly protruding connection portion 353, the shape of the bus bar 35 is not limited thereto. The bus bar 35 may also have a flat plate shape in which the first plate-shaped portion 351 and the second plate-shaped portion 352 are connected flatly.

[0060] In the above-mentioned embodiment, the case where a plurality of protrusions 42 are provided in a one-to-one correspondence on a plurality of external terminals is illustrated, but as long as the protrusions 42 are provided at positions corresponding to the external terminals, the number of the protrusions 42 can be appropriately changed according to the desired load capacity.

[0061] While the embodiments of the present invention have been described, the embodiments disclosed herein are to be construed as illustrative in all respects and not restrictive. The scope of the present invention is indicated by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.

Claims

1. A power storage device, wherein: The power storage device comprises: a plurality of power storage cells, each including an external terminal, wherein the plurality of power storage cells are arranged in an arrangement direction; A housing shell, comprising an upper shell and a lower shell, for housing the plurality of power storage cells; a bus bar module, configured to electrically connect the plurality of power storage cells; as well as a cover body disposed between the upper case and the bus bar module so as to be in contact with a portion of the upper case; The plurality of power storage cells are fixed to the lower housing. The bus bar module includes a plurality of bus bars for connecting the external terminals of the power storage cells adjacent to each other in the arrangement direction. The cover includes a facing portion facing the plurality of bus bars. The facing portion is provided with a protrusion that contacts the bus bar. The cover includes an upper surface portion, the upper surface portion facing the side opposite to the side where the bus bar is located and capable of abutting against the portion of the upper case. The upper surface portion is provided flatly.

2. The power storage device according to claim 1, wherein The bus bar has a welded portion welded to the external terminal. The protrusion is in contact with the bus bar while being separated from the welded portion.

3. The power storage device according to claim 2, wherein The bus bar includes a plate-shaped portion having a first surface and a second surface that are opposite to each other and is placed on the external terminal. The second surface is placed on the external terminal, and the first surface faces the side opposite to the side where the external terminal is located. The first surface is provided with a recessed portion that is recessed toward the second surface. The welded portion is provided at the bottom of the recessed portion. The protrusion has a flat surface portion in contact with the first surface. The flat surface portion contacts the first surface across the recessed portion without contacting the welded portion.

4. The power storage device according to any one of claims 1 to 3, wherein The protrusion has a weight-reducing portion.

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