WO2020008681A1 - Secondary battery module - Google Patents

Abstract

A secondary battery module 1 is provided with: first and second laminates 11, 12 that are each formed by laminating a plurality of battery cells 10 and that are arrayed orthogonally to the laminating direction; and an inter-laminate bus bar 30 that is laid between the first and second laminates 11, 12 and that electrically connects the battery cells 10 of these laminates. The inter-laminate bus bar 30 has a projected first vibration absorption part 301 that is disposed on the first laminate 11 side so as to extend in the arraying direction of the first and second laminates 11, 12, a projected second vibration absorption part 302 that is disposed on the second laminate 12 side so as to extend in the arraying direction, and a dividing part 303 that is disposed between the first and second vibration absorption parts 301, 302.

Description

Rechargeable battery module

The present invention relates to a secondary battery module, and more particularly, to a secondary battery module used for a vehicle.
This application claims priority based on Japanese Patent Application No. 2018-129065 filed on July 6, 2018, the contents of which are incorporated herein by reference.

Conventionally, in the field of rechargeable secondary batteries, aqueous batteries such as lead batteries, nickel-cadmium batteries, and nickel-hydrogen batteries have been the mainstream. However, as electric devices have become smaller and lighter, attention has been paid to lithium ion secondary batteries having a high energy density, and research, development, and commercialization thereof have been rapidly advanced. In particular, prismatic lithium-ion secondary batteries have excellent volumetric efficiency when modularized (also referred to as packs), and have begun to be deployed in automotive applications for HEVs (hybrid vehicles) or EVs (electric vehicles). I have.

In a vehicle, a load such as vibration or impact may be applied to the secondary battery module. Further, in the battery cells constituting the secondary battery module, deformation occurs due to expansion and contraction, and a load may be applied to the secondary battery module due to the deformation. As a structure that is not easily broken by these loads, Patent Document 1 below discloses a structure in which a bus bar that electrically connects terminals of adjacent battery cells is provided with a vibration-absorbing portion that is convexly curved. In addition, the required performance of lithium ion secondary batteries is increasing year by year, and in order to respond to the demands for higher current and higher capacity, batteries in which battery cells are connected in parallel are being studied. Patent Literature 2 below discloses a secondary battery module provided with a bus bar that connects a plurality of battery cells in parallel.

JP 2013-197017 A JP 2011-65794 A

In the secondary battery module disclosed in Patent Document 2 described above, a technique of connecting a stacked body in which a plurality of battery cells are stacked with a wide bus bar is shown. However, loads such as vibration and impact are applied to the wide bus bar. There is no structure that absorbs the load caused by the expansion and contraction of the battery cell, and when a large vibration or shock is applied, or when the battery cell expands and contracts due to long-term use or charge and discharge, the bus bar and the battery cell There is a concern that the load may be concentrated on the connection part of the above and the connection part may be damaged.

に 対 し て On the other hand, it has been considered to apply the vibration absorbing structure disclosed in Patent Literature 1 to the wide bus bar of Patent Literature 2. For example, as shown in FIG. 7, in the inter-stack bus bar 40 arranged between adjacent stacks, one end of the bus bars 40 is arranged along the direction in which the stacks are arranged (ie, the direction orthogonal to the stacking direction of the battery cells). It is considered that the above-described load is absorbed by providing the convex vibration absorbing portion 401 extending to the other end.

However, in the bus bar between the stacked bodies configured as described above, the load such as vibration and impact in the stacking direction of the battery cells and the load due to the expansion and contraction of the battery cells can be absorbed by the vibration absorbing portion. It is difficult to cope with loads such as vibrations and shocks in the arrangement direction of the bodies, loads caused by torsion between the stacked bodies, and the like. For this reason, the load concentrates on the connection part between the inter-stack bus bar and the battery cell, and the connection part may be damaged. Therefore, there is a problem that the connection reliability between the inter-stack bus bar and the battery cell is impaired.

The present invention has been made in order to solve such a technical problem, and reduces a load on a connection portion between a stacked body bus bar and a battery cell, and reduces a connection reliability between the stacked body bus bar and a battery cell. It is an object of the present invention to provide a secondary battery module capable of improving performance.

The secondary battery module according to the present invention includes a first stacked body and a second stacked body each formed by stacking a plurality of battery cells and arranged along a direction orthogonal to a stacking direction of the battery cells, A stacked body that is bridged between a first stacked body and the second stacked body and electrically connects the plurality of battery cells of the first stacked body and the plurality of battery cells of the second stacked body. A bus bar, wherein the inter-laminate bus bar is disposed on the first laminate side, and has a convex first vibration absorbing portion extending in an arrangement direction of the first laminate and the second laminate. A convex second vibration absorber arranged on the side of the second laminate and extending in an arrangement direction of the first laminate and the second laminate, the first vibration absorber and the second vibration absorber; And a dividing part disposed between the two.

According to the present invention, the inter-laminate bus bar is disposed on the first laminate side and extends in the direction in which the first laminate and the second laminate are arranged. A convex second vibration absorbing portion that is arranged and extends in the arrangement direction of the first laminate and the second laminate, and a dividing portion that is disposed between the first vibration absorbing portion and the second vibration absorbing portion. Accordingly, the load on the connection between the inter-laminate bus bar and the battery cell can be reduced, and the connection reliability between the inter-laminate bus bar and the battery cell can be improved.

FIG. 2 is a perspective view showing the secondary battery module according to the first embodiment. It is a perspective view which shows a battery cell. FIG. 3 is an exploded perspective view showing a first stacked body and a second stacked body. It is a perspective view which shows the bus bar between laminated bodies. It is a perspective view which shows the bus bar between laminated bodies of the secondary battery module which concerns on 2nd Embodiment. It is a perspective view which shows the bus bar between laminated bodies of the secondary battery module which concerns on 3rd Embodiment. It is a perspective view which shows the conventional bus bar between laminated bodies.

Hereinafter, embodiments of the secondary battery module according to the present invention will be described with reference to the drawings. In the following description, positions such as up and down are provided for convenience according to the drawings in order to avoid complicating the description, and do not necessarily indicate positions in an actual use state. In order to avoid this, the “stacking direction of the battery cells” may be abbreviated as the “stacking direction” and the “array direction of the first stack and the second stack” may be abbreviated as the “array direction”.

[First Embodiment]
FIG. 1 is a perspective view showing the secondary battery module according to the first embodiment. The secondary battery module 1 of the present embodiment mainly includes a plurality of battery cells 10 stacked on each other, and a first stacked body 11 and a second stacked body 11 arranged in a direction orthogonal to the stacking direction of the battery cells 10. It comprises a two-layered body 12 and a holding body 20 for holding the arranged first and second stacked bodies 11 and 12.

Each of the first stacked body 11 and the second stacked body 12 includes a plurality of (here, six) flat rectangular battery cells 10 arranged according to a predetermined rule, and a double-sided protrusion between adjacent battery cells 10. They are laminated with an insulating plate 18 interposed and one-sided protruding insulating plates 19 arranged at both ends in the laminating direction. Before describing the structures of the first stacked body 11 and the second stacked body 12 in detail, the structure of the battery cell 10 will be described with reference to FIG.

FIG. 2 is a perspective view showing a battery cell. As shown in FIG. 2, the battery cell 10 is a flat secondary battery, and includes a battery can 13 and a battery cover 14. The battery can 13 has a so-called square cylindrical shape with a bottom. It has a surface portion 13b and a pair of narrow surface portions 13c having relatively small areas and facing each other. Inside the battery can 13, for example, an electrode group and an electrolytic solution wound in a flat shape are accommodated.

The battery lid 14 is arranged at a position facing the bottom of the can, and is joined to the battery can 13 so as to close the opening of the battery can 13. As a joining method, laser welding or the like can be given. As shown in FIG. 2, the battery cover 14 is also a narrow surface portion, and the battery cover 14 is provided with a positive electrode terminal 15 and a negative electrode terminal 16. The positive electrode terminal 15 and the negative electrode terminal 16 are connected to the positive electrode side bus bar 31, the inter-cell bus bar 32, the negative electrode side bus bar 33, or the laminated body bus bar 30 (described later) by laser welding, respectively. The end is formed in a planar shape.

に お い て Further, on the battery lid 14, on the side near the negative electrode terminal 16, a liquid injection plug 17 for closing the liquid injection hole for the electrolyte is provided. The filling plug 17 is joined to the battery cover 14 by laser welding, for example, after filling the inside of the battery cell 10 with an electrolytic solution through a filling port.

FIG. 3 is an exploded perspective view showing the first laminate and the second laminate. Since the first stacked body 11 and the second stacked body 12 have the same structure, an example of the first stacked body 11 will be described here. As shown in FIG. 3, the first stacked body 11 is configured by stacking six battery cells 10 in a state where the wide surface portions 13b face each other. The six battery cells 10 are connected in two parallels and two series.

Specifically, the two battery cells 10 are stacked such that the positive electrode terminal 15 of one battery cell 10 and the positive electrode terminal 15 of the other battery cell 10 are adjacent to each other in the stacking direction. Constitute. Therefore, the first stacked body 11 includes three such cell blocks (a lower cell block, an intermediate cell block, and an upper cell block arranged in order in the stacking direction in FIG. 1). In the three cell blocks, the positive terminal group (ie, two positive terminals 15) of one adjacent cell block and the negative terminal group (ie, two negative terminals 16) of the other cell block are arranged in the stacking direction. The layers are alternately turned 180 ° so as to be adjacent to each other.

両 面 As shown in FIG. 3, a double-sided projection insulating plate 18 having a projection 18a is interposed between adjacent battery cells 10. In addition, a single-sided projection insulating plate 19 having a projection 19a is arranged outside the battery cell 10 positioned outermost in the stacking direction. The double-sided projection insulating plate 18 and the single-sided projection insulating plate 19 are formed of a resin material such as PBT (polybutylene terephthalate).

As shown in FIG. 1, of the three cell blocks constituting the first stacked body 11, the positive terminals 15 of the lower cell block are connected in parallel by a positive end bus bar 31. On the other hand, the negative electrode terminals 16 of the lower cell block are connected in parallel by the inter-cell bus bar 32 and further connected in series to the positive electrode terminals 15 of the adjacent intermediate cell block by the inter-cell bus bar 32. That is, the inter-cell bus bar 32 connects the negative terminals 16 of the lower cell block and the positive terminals 15 of the intermediate cell block in parallel with each other, and further connects these terminals in series.

Similarly, the negative electrode terminals 16 of the intermediate cell block are connected in parallel by the inter-cell bus bar 32, and further connected in series with the positive electrode terminals 15 of the adjacent upper cell block by the inter-cell bus bar 32. The negative electrode terminals 16 of the upper cell block are connected in parallel by the inter-laminate bus bar 30 (described later), and further connected to the positive electrode terminal 15 of the upper cell block of the second laminate 12 by the inter-laminate bus bar 30. They are connected in series.

The positive-electrode-side end busbar 31 corresponds to the “busbar in the laminate” described in the claims. The positive-side end bus bar 31 is formed in a plate shape from, for example, a nickel material, and is mounted on these terminals so as to cover the adjacent positive terminals 15 by laser welding or screwing. It is joined with the terminal. As shown in FIG. 1, the positive-side end bus bar 31 includes a convex vibration absorbing portion 31 a located between adjacent positive-electrode terminals 15, a projecting outside of the secondary battery module 1, and a module external connection terminal. And an overhanging portion 31b that functions as The vibration absorbing portion 31a has a substantially U-shaped cross section, and extends in the direction in which the secondary battery module 1 and the second stacked body 12 are arranged. By providing the vibration absorbing portion 31a in this way, it is possible to absorb loads such as vibrations and impacts in the stacking direction of the battery cells 10, and loads caused by expansion and contraction of the battery cells 10.

The inter-cell busbar 32 corresponds to the “busbar in the laminate” described in the claims. The inter-cell bus bar 32 is formed in a flat plate shape from, for example, a nickel material, and is placed on the adjacent positive electrode terminals 15 and negative electrode terminals 16 so as to cover the adjacent terminals. And these terminals are joined. As shown in FIG. 1, in the inter-cell bus bar 32, one between each of the adjacent positive terminals 15, between each of the adjacent negative terminals 16, and between each of the adjacent positive and negative terminals 15 and 16. Each of the convex vibration absorbing portions 32a is disposed. Each of the vibration absorbing portions 32a has a substantially U-shaped cross section, and extends in the arrangement direction of the secondary battery module 1 and the second stacked body 12.

The second stacked body 12 further includes a negative electrode side end bus bar 33 in addition to the inter-cell bus bars 32, similarly to the first stacked body 11. As shown in FIG. 1, the negative electrode side end bus bar 33 connects the negative electrode terminals 16 of the lower cell block in the second stacked body 12 to each other in parallel. The negative-electrode-side end busbar 33 corresponds to the “busbar in the laminate” described in the claims, and includes a convex vibration absorbing portion 33a located between adjacent negative terminals 16 and a secondary A projecting portion 33b that extends outside the battery module 1 and functions as a module external connection terminal. The vibration absorbing portion 33a has a substantially U-shaped cross section, and extends in the direction in which the secondary battery module 1 and the second stacked body 12 are arranged.

On the other hand, the sandwiching body 20 includes a pair of side plates 21 arranged on both sides in the arrangement direction of the first stacked body 11 and the second stacked body 12, and a pair of end plates arranged on both sides in the stacking direction of the battery cells 10. It has a plate 22 and a center plate 23 disposed between the pair of side plates 21 so as to partition the first stacked body 11 and the second stacked body 12. The side plate 21, the end plate 22, and the center plate 23 are formed of, for example, a metal material, and are fixed to each other by a plurality of screws 24.

Hereinafter, the structure of the inter-layer body bus bar 30 will be described with reference to FIG. 1 and FIG. FIG. 4 is a perspective view showing a bus bar between laminated bodies. The inter-laminate bus bar 30 is formed in a plate shape from, for example, a nickel material, is bridged between the first laminate 11 and the second laminate 12, and is connected to the upper cell block of the first laminate 11 and the second cell block. The upper cell block of the stacked body 12 is electrically connected. The inter-laminate bus bar 30 is disposed on the first laminate 11 side, and has a convex first vibration absorbing portion 301 extending in the direction in which the first laminate 11 and the second laminate 12 are arranged; Between the first vibration absorber 301 and the second vibration absorber 302, which is disposed on the side of the second vibration absorber 12 and extends in the direction in which the first laminate 11 and the second laminate 12 are arranged. And a dividing portion 303 arranged at the same position.

The first vibration absorbing portion 301 has a substantially U-shaped cross section, and is formed on the first stacked body 11 side of the inter-stacked bus bar 30 so as to be located between the adjacent negative electrode terminals 16. The second vibration absorbing portion 302 has a substantially U-shaped cross section, and is formed on the second stacked body 12 side of the inter-stacked bus bar 30 so as to be located between the adjacent positive electrode terminals 15. In the present embodiment, the first vibration absorber 301 and the second vibration absorber 302 are arranged coaxially, but may be arranged so as to be shifted from each other (that is, offset). Further, the first vibration absorbing portion 301 and the second vibration absorbing portion 302 may have the same length in the arrangement direction, the protrusion height, the width in the stacking direction, and the like, or may have different lengths. Further, the first vibration absorbing section 301 and the second vibration absorbing section 302 do not necessarily have to have a substantially U-shaped cross section, but may have a V-shaped cross section or a rectangular cross section.

The dividing part 303 is a flat part formed between the first vibration absorbing part 301 and the second vibration absorbing part 302.

Further, through holes 304 are provided on both sides of the first vibration absorbing section 301 with the first vibration absorbing section 301 interposed therebetween, and on both sides of the second vibration absorbing section 302 with the second vibration absorbing section 302 interposed therebetween. Have been. The through-hole 304 functions as an insertion hole for a joining screw or a positioning hole at the time of laser welding when the inter-layer body bus bar 30 is joined to the positive electrode terminal 15 or the negative electrode terminal 16.

In the secondary battery module 1 having the above configuration, the inter-laminate bus bar 30 is disposed on the first laminate 11 side and has a convex shape extending in the arrangement direction of the first laminate 11 and the second laminate 12. A first vibration absorbing section 301, a convex second vibration absorbing section 302 disposed on the second stacked body 12 side and extending in the arrangement direction, and disposed between the first vibration absorbing section 301 and the second vibration absorbing section 302. And a dividing section 303. Therefore, a load such as vibration or impact in the stacking direction of the battery cells 10 and a load resulting from expansion and contraction of the battery cells 10 are absorbed through the first vibration absorbing portions 301 and the second vibration absorbing portions 302 extending in the arrangement direction. be able to.

In addition, the dividing portion 303 disposed between the first vibration absorbing portion 301 and the second vibration absorbing portion 302 causes a load such as a vibration or an impact in the arrangement direction of the first laminated body 11 and the second laminated body 12, The load caused by the twist between the first stacked body 11 and the second stacked body 12 can be absorbed. As a result, a connection portion between the inter-laminate bus bar 30 and the positive electrode terminal 15 (that is, a joint portion between the inter-laminate bus bar 30 and the positive electrode terminal 15) and a connection portion between the inter-laminate bus bar 30 and the negative electrode terminal 16 (that is, the connection portion) The load on the inter-laminate bus bar 30 and the negative electrode terminal 16) can be reduced, and the connection reliability between the inter-laminate bus bar 30 and the positive electrode terminal 15 or the negative electrode terminal 16 can be improved.

[Second embodiment]
FIG. 5 is a perspective view showing the inter-stack busbar of the secondary battery module according to the second embodiment. The secondary battery module of the present embodiment is different from the above-described first embodiment in the shape of the bus bar between the stacked bodies. In the following description, only the differences will be described.

As shown in FIG. 5, the dividing portion 303A of the inter-stack bus bar 30A is a convex vibration absorbing portion extending from one end to the other end in the stacking direction of the battery cells 10. The dividing portion 303A has a substantially U-shaped cross section, and is disposed between the first vibration absorbing portion 301 and the second vibration absorbing portion 302 so as to cross the inter-laminate bus bar 30A.

According to the secondary battery module including the inter-stacked bus bar 30A, the same operation and effect as those of the first embodiment can be obtained, and the dividing section 303A is a convex vibration absorbing section. As compared with the above, the effect of absorbing a load such as vibration or impact in the arrangement direction and a load resulting from the twist between the first stacked body 11 and the second stacked body 12 can be further enhanced.

[Third Embodiment]
FIG. 6 is a perspective view showing the inter-stack busbar of the secondary battery module according to the third embodiment. The secondary battery module of the present embodiment is different from the above-described first embodiment in the shape of the bus bar between the stacked bodies. In the following description, only the differences will be described.

よ う As shown in FIG. 6, the dividing portion 303B of the inter-laminate bus bar 30B is a hole penetrating the inter-laminate bus bar 30B. The dividing section 303B is arranged between the first vibration absorbing section 301 and the second vibration absorbing section 302 so as to divide the communicating first vibration absorbing section 301 and second vibration absorbing section 302.

According to the secondary battery module including the inter-laminate bus bar 30B, the same operation and effect as in the first embodiment can be obtained, and the dividing portion 303B is a hole penetrating the inter-laminate bus bar 30B. Compared to the first embodiment, it is possible to further enhance the effect of absorbing loads such as vibrations and shocks in the arrangement direction, and loads caused by torsion between the first stacked body 11 and the second stacked body 12, and the stacked body. The material used for the inter-busbar 30B can be reduced.

As described above, the embodiments of the present invention have been described in detail. However, the present invention is not limited to the above embodiments, and various designs may be made without departing from the spirit of the present invention described in the claims. Changes can be made. For example, in the above-described embodiment, an example has been described in which the inter-laminate bus bar 30, the positive-side end bus bar 31, the inter-cell bus bar 32, and the negative-side end bus bar 33 are formed of a nickel material. It may be formed of a metal material or a metal composite material.

DESCRIPTION OF SYMBOLS 1 Secondary battery module 10 Battery cell 11 First stacked body 12 Second stacked body 15 Positive electrode terminal 16 Negative terminal 17 Injection plug 18 Double-sided projecting insulating plate 18a, 19a Projecting 19 Single-sided projecting insulating plate 20 Clamping body 21 Side plate 22 End Plate 23 Center plate 24 Screws 30, 30A, 30B Inter-layer bus bar 31 Positive end bus bar 31a Vibration absorbing portion 31b Overhang portion 32 Inter-cell bus bar 32a Vibration absorbing portion 33 Negative end bus bar 33a Vibration absorbing portion 33b Overhang Part 40 Interlayer bus bar 301 First vibration absorbing part 302 Second vibration absorbing parts 303, 303A, 303B Dividing part 304 Through hole 401 Vibration absorbing part

Claims (7)

A first stacked body and a second stacked body each formed by stacking a plurality of battery cells and arranged along a direction orthogonal to the stacking direction of the battery cells;
A laminate that is bridged between the first laminate and the second laminate and electrically connects the plurality of battery cells of the first laminate and the plurality of battery cells of the second laminate. Interbody busbar,
With
The bus bar between the laminates,
A first vibration absorbing portion having a convex shape, which is disposed on the first laminate side and extends in an arrangement direction of the first laminate and the second laminate;
A convex second vibration absorbing portion disposed on the second laminate side and extending in an arrangement direction of the first laminate and the second laminate;
A dividing portion disposed between the first vibration absorbing portion and the second vibration absorbing portion;
A secondary battery module comprising: 2. The secondary battery module according to claim 1, wherein each of the first stacked body and the second stacked body further includes a plurality of the battery cells connected in parallel, further connected in series. 3. The battery cell is a flat secondary battery having a wide surface portion and a narrow surface portion,
A positive electrode terminal and a negative electrode terminal are provided on the narrow surface portion,
The first laminate and the second laminate are each formed by laminating a plurality of the battery cells such that the wide surface portions face each other,
The secondary battery module according to claim 1, wherein the inter-stack bus bar connects the plurality of negative terminals of the first stack and the plurality of positive terminals of the second stack. The device according to any one of claims 1 to 3, wherein the dividing portion is a hole disposed between the first vibration absorbing portion and the second vibration absorbing portion and penetrating the inter-layer body bus bar. Secondary battery module. The secondary battery module according to any one of claims 1 to 3, wherein the dividing part is a flat part disposed between the first vibration absorbing part and the second vibration absorbing part. 4. The vibration separating section according to claim 1, wherein the dividing section is a convex vibration absorbing section that is disposed between the first vibration absorbing section and the second vibration absorbing section and extends in the stacking direction. Rechargeable battery module. The first stacked body and the second stacked body each have a bus bar in the stacked body for electrically connecting the adjacent battery cells in each stacked body,
The secondary battery module according to any one of claims 1 to 6, wherein the bus bar in the stack has a convex vibration absorbing portion extending in the arrangement direction.

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