阅读说明：本技术 电池模块 (Battery module ) 是由 浦野和昭 增田洋昭 川崎龙彦 久保田修 于 2019-10-17 设计创作，主要内容包括：本发明的课题在于获得一种可以在母线的异种金属间的接合部确保高接合强度的电池模块。本发明的电池模块(100)具有：多个单电池(1),它们具有单元端子(1p、1n)；以及母线(2A),其将若干单电池(1)的端子彼此相连,母线(2A)具有：多个连接面部(2c1、2c2),它们连接到单电池(1)的单元端子(1p、1n)；多个立起部,它们从这多个连接面部(2c1、2c2)立起；以及连接部,其将这多个立起部之间连接在一起,而且母线(2A)是由包含铜的铜部分(2e)和具有铝的铝部分(2f)构成,铜部分(2e)与铝部分(2f)的接合部形成于连接面部(2c1、2c2)。(The invention aims to obtain a battery module which can ensure high bonding strength at a bonding part between dissimilar metals of a bus bar. A battery module (100) of the present invention includes: a plurality of cells (1) having cell terminals (1p, 1 n); and a bus bar (2A) that connects terminals of the plurality of single cells (1) to each other, the bus bar (2A) having: a plurality of connecting surface sections (2c1, 2c2) that are connected to cell terminals (1p, 1n) of the single cell (1); a plurality of rising portions rising from the plurality of connecting surface portions (2c1, 2c 2); and a connecting portion that connects the plurality of rising portions together, and the bus bar (2A) is composed of a copper portion (2e) containing copper and an aluminum portion (2f) having aluminum, and a joint portion of the copper portion (2e) and the aluminum portion (2f) is formed at the connecting surface portions (2c1, 2c 2).)

1. A battery module, comprising:

a plurality of batteries having terminals; and

a bus bar connecting terminals of the cells to each other,

the bus bar has: a plurality of connecting face portions connected to each of the connected terminals; a plurality of rising portions rising from each of the plurality of connection face portions; and a connecting portion connecting the plurality of rising portions, and the bus bar is composed of a copper portion containing copper and an aluminum portion having aluminum,

the copper portion is bonded to the aluminum portion,

the joint portion of the copper portion and the aluminum portion is formed at the connecting surface portion.

2. The battery module according to claim 1,

the bus bar has a pair of connecting surface portions arranged in a planar arrangement adjacent to each other,

one of the pair of joint surfaces is a dissimilar metal joint site where the aluminum portion and the copper portion are overlapped and joined together.

3. The battery module according to claim 2,

the one connecting surface portion has:

a flat plate portion composed of either the copper portion or the aluminum portion, joined to a terminal of the battery; and

and a pair of arm portions formed of either the copper portion or the aluminum portion, protruding from the rising portion in parallel to each other in pairs, and overlapped and joined to the flat plate portion.

4. The battery module according to claim 3,

the flat plate portion is provided with a registration hole at a portion exposed between the pair of arm portions, the registration hole being used to join the flat plate portion to a terminal of the battery by laser welding.

5. The battery module according to claim 3,

the flat plate portion has a base portion and a claw portion respectively opposed to the arm portion on one side and the other side in an overlapping direction overlapping with the arm portion,

the engaging portion is formed at an overlapping portion of the arm portion and the claw portion of the flat plate portion.

6. The battery module according to claim 1,

the engaging portion is formed in a portion of the connecting surface portion that avoids an engaging portion of the bus bar and the terminal.

7. The battery module according to claim 2,

the one connection face portion has a detection conductor for detecting a voltage of the battery,

the detection conductor is connected to a portion of the connection surface portion that avoids the joint portion and the joint portion of the bus bar and the terminal.

8. A battery module, comprising:

a plurality of batteries having terminals; and

a bus bar connecting terminals of the cells to each other,

the bus bar has: a plurality of connecting face portions connected to each of the connected terminals; a plurality of rising portions rising from each of the plurality of connection face portions; and a connecting portion connecting the plurality of rising portions, and the bus bar is composed of a copper portion containing copper and an aluminum portion having aluminum,

the copper portion is bonded to the aluminum portion,

the joint portion of the copper portion and the aluminum portion is formed at the rising portion, and a part of the surface of the copper portion and a part of the surface of the aluminum portion are bent in a hook shape, and inner surface sides of the copper portion and the aluminum portion are joined to each other in an opposing manner.

9. The battery module according to claim 8,

the bus bar has a pair of rising portions facing each other,

one of the pair of rising portions is a dissimilar metal joint portion where the aluminum portion and the copper portion are overlapped and joined together.

10. The battery module according to claim 9,

the one rising portion has:

a 1 st flat rectangular portion formed of either the copper portion or the aluminum portion and formed continuously with the connecting surface portion; and

and a 2 nd flat plate rectangular portion which is formed of either the copper portion or the aluminum portion, is formed continuously with the connecting portion, and has a side surface facing the other rising portion overlapped and joined to a side surface of the 1 st flat plate rectangular portion on the side of the connecting surface portion.

11. The battery module according to claim 10,

the other rising portion and the connecting portion are provided with a notch portion for exposing the 1 st flat plate rectangular portion.

12. The battery module according to any one of claims 1 to 11,

the joint is plated with tin or nickel.

13. The battery module according to claim 1,

the joint is formed in such a manner that the aluminum portion and a part of the copper portion are vertically overlapped and sandwiched.

Technical Field

The present invention relates to a battery module including a plurality of batteries.

Background

A plurality of cells constituting a battery module connect terminals to each other via connecting conductors called bus bars. As a background art related to the bus bar, for example, a technique disclosed in patent document 1 is cited. Patent document 1 describes a bus bar including: a copper portion (701) made of a copper material, laser-welded on the negative electrode group; and an aluminum portion (702) made of an aluminum material, laser-welded on the cell positive electrode group; the 2 sections consisting of these two metals were welded linearly to each other using ultrasonic roll seam welding (705) (cf. paragraphs 0064, 0067, fig. 15).

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2012-515418

Disclosure of Invention

Problems to be solved by the invention

Stress acts on the bus bars connecting the terminals of the plurality of cells to each other due to vibration applied to the battery module, swelling caused by charge and discharge of the cells, and the like. Therefore, in the bus bar in which dissimilar metals are joined as in the technique of patent document 1, in order to prevent the separation of the joint between the dissimilar metals even if stress is applied to the joint between the dissimilar metals, it is necessary to ensure high joining strength.

Means for solving the problems

One of the typical problems of the present application is to ensure high bonding strength at a bonding portion between dissimilar metals of a bus bar.

A representative invention of the present application for solving the above problems is a battery module including: a plurality of batteries having terminals; and a bus bar connecting terminals of the plurality of cells to each other, the bus bar having: a plurality of connection face portions connected to terminals of the battery; a plurality of rising portions rising from each of the plurality of connecting surface portions; and a connecting portion connecting between the plurality of rising portions, and the bus bar is composed of a copper portion containing copper and an aluminum portion having aluminum, and a joint portion of the copper portion and the aluminum portion is formed at a connecting surface portion connected to a terminal of the battery. The connection surface portion formed with the joint portion of the copper portion and the aluminum portion is connected to a terminal of a battery, which is a strength member. This increases the rigidity of the joint between the copper portion and the aluminum portion, thereby increasing the natural frequency, and reducing the stress acting on the joint between the copper portion and the aluminum portion. Thus, high bonding strength can be ensured at the bonding portion of the copper portion and the aluminum portion.

Another representative invention of the present application for solving the above-described problems is a battery module in which a joint portion of a copper portion and an aluminum portion is formed at a rising portion rising from a connecting surface portion, and a partial surface of the copper portion and a partial surface of the aluminum portion forming the rising portion are bent in a hook shape, and inner surface sides of the copper portion and the aluminum portion are joined to face each other. When a part of the surface of the copper portion and a part of the surface of the aluminum portion forming the rising portion are bent in a hook shape and the inner surface sides of the copper portion and the aluminum portion are joined to each other in a facing manner, a reaction force in a direction opposite to a direction of a stress acting on the joint of the copper portion and the aluminum portion is applied to the joint of the copper portion and the aluminum portion, and thus the stress acting on the joint of the copper portion and the aluminum portion is reduced. Thus, high bonding strength can be ensured at the bonding portion of the copper portion and the aluminum portion.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, since high bonding strength can be secured at the bonding portion between dissimilar metals including the copper portion and the aluminum portion, the resistance of the battery module against vibration and the like can be improved, and a highly reliable battery module having excellent resistance can be provided.

Further features of the present invention will be apparent from the description and drawings of the present specification. Problems, configurations, and effects other than those described above will be apparent from the following description of the embodiments.

Drawings

Fig. 1 is an external perspective view of a battery module according to embodiment 1 of the present invention.

Fig. 2 is an exploded perspective view of the battery module shown in fig. 1.

Fig. 3 is an enlarged cross-sectional view showing a section of a main portion of the battery module shown in fig. 1.

Fig. 4 is a perspective view of the bus bar shown in fig. 3.

Fig. 5 is a top view of the bus bar shown in fig. 3.

Fig. 6 is an enlarged perspective view of a module terminal of the battery module shown in fig. 1.

Fig. 7 is an enlarged sectional view of the module terminal along line VII-VII of fig. 6.

Fig. 8 is a perspective view of a fused busbar connected to one of the module terminals shown in fig. 6.

Fig. 9 is a perspective view of a bus bar connected to another module terminal different from the module terminal shown in fig. 6.

Fig. 10 is a perspective view of a bus bar connecting unit cells of a battery module according to embodiment 2 of the present invention.

Fig. 11 is a top view of the bus bar shown in fig. 10.

Fig. 12 is a side view of the bus bar shown in fig. 10.

Fig. 13 is a perspective view of a bus bar connecting unit cells of a battery module according to embodiment 3 of the present invention.

Fig. 14 is a top view of the bus bar shown in fig. 13.

Fig. 15 is a side view of the bus bar shown in fig. 13.

Fig. 16 is a perspective view of a bus bar provided on a cell terminal.

Fig. 17 is a perspective view of a bus bar having a structure in which a voltage detection line joint portion is provided in a copper portion constituting a connection surface portion.

Fig. 18 is a perspective view of a bus bar having a structure in which a voltage detection line joint portion is provided in an aluminum portion constituting a connection surface portion.

Detailed Description

Embodiments of the present invention will be described below with reference to the drawings.

In the case of explaining the structure of each part of the battery module using each drawing, an orthogonal coordinate system of x-axis, y-axis, and z-axis shown in the drawing or each direction of up, down, left, right, front, and rear is used, but the use of these axes and directions is for convenience of explanation and does not limit the posture and arrangement of the battery module.

[ embodiment 1]

Fig. 1 to 9 are views showing embodiment 1 of the present invention.

First, the structure of the battery module 100 will be described with reference to fig. 1 and 2. Here, fig. 1 is an external perspective view of the battery module 100, and fig. 2 is an exploded perspective view of the battery module 100.

The battery module 100 mainly includes: module terminals 101P, 101N, which are external terminals; an assembled battery 10 including a plurality of single cells 1; and a bus bar 2 electrically and mechanically connecting the plurality of unit cells 1 of the battery pack 10, and electrically and mechanically connecting the battery pack 10 and the module terminals 101P and 101N. In the present embodiment, the bus bar 2 electrically and mechanically connecting the plurality of electric cells 1 has the greatest feature, and is configured as described later in detail. Further, the battery module 100 includes the case 20, an electronic circuit board, and the like, which are not shown, in addition to the aforementioned components.

The assembled battery 10 is configured by stacking flat rectangular unit cells 1, that is, unit cells 1 in the shape of a thin hexahedron or a rectangular parallelepiped whose thickness is smaller than the width and the height, in the thickness direction (x-axis direction). The single cell 1 is a prismatic lithium ion secondary battery, and includes a flat prismatic battery container 1a, an electrode group and an electrolyte solution, not shown, housed in the battery container 1a, and a pair of unit terminals 1p, 1n connected to the electrode group and disposed on an upper end surface of the battery container 1a in the height direction. Here, the cell terminal 1p is a positive terminal, and the cell terminal 1n is a negative terminal.

The cell terminals 1p and 1n of the single cell 1 have a substantially rectangular solid shape protruding in the height direction from the upper end surface of the battery container 1 a. The cell terminals 1p and 1n and the battery case 1a and the electrode group are electrically insulated from each other by resin insulating members. The plurality of unit cells 1 constituting the battery assembly 10 are stacked by alternately turning over 180 ° so that a unit terminal 1p of a positive electrode of one unit cell 1 adjacent to each other and a unit terminal 1n of a negative electrode of the other unit cell 1 are adjacent to each other in the stacking direction (x-axis direction).

The case 20 has a substantially rectangular parallelepiped shape having a dimension in the longitudinal direction (x-axis direction) larger than the dimensions in the width direction (y-axis direction) and the height direction (z-axis direction), and holds the plurality of cells 1 constituting the battery assembly 10. More specifically, the case 20 has a plurality of unit frames 21, a pair of end plates 22, a pair of side plates 23, an insulating cover 24, and a module cover 25.

The cell frame 21 is made of a resin material such as Polybutylene terephthalate (PBT). The unit holder 21 is interposed between mutually adjacent unit cells 1 of the plurality of unit cells 1 stacked together in the thickness direction (x-axis direction), and holds each unit cell 1 so as to sandwich it from both sides in the thickness direction (x-axis direction). In the stacking direction (x-axis direction) of the plurality of cells 1 constituting the battery assembly 10, module terminals 101P and 101N, which are external terminals of the battery module 100, are provided on a pair of unit frames 21 disposed on both sides of the battery assembly 10. Here, the module terminal 101P is a positive terminal, and the module terminal 101N is a negative terminal.

The pair of end plates 22 are metal plate members. In the stacking direction (x-axis direction) of the plurality of unit cells 1 constituting the battery assembly 10, a pair of end plates 22 are disposed on both sides of the battery assembly 10 with a pair of unit frames 21 disposed on both sides of the battery assembly 10 interposed therebetween. One surfaces of the pair of end plates 22 face each other so as to sandwich the plurality of unit cells 1 held in the unit frame 21, and a fixing portion 22a is provided on the other surface facing the opposite side of the battery pack 10, i.e., the outer side.

The fixing portions 22a provided in the pair of end plates 22 are formed in a substantially cylindrical shape, and a part of the cylindrical surface protrudes outward from the outer surface of the end plate 22. The cylindrical fixing portion 22a has a screw hole formed by punching along a central axis parallel to the height direction (z-axis direction) of the end plate 22. The fixing portion 22a of the end plate 22 is a portion for fixing the battery module 100 to an external mechanism such as a vehicle or other machinery. The lower end surface of the fixing portion 22a of the end plate 22 is a support surface 20a of the case 20 supported by the external mechanism as described above.

That is, the battery module 100 can be fixed to an external mechanism by supporting the bottom surface of the fixing portion 22a of the end plate 22, that is, the supporting surface 20a of the case 20, by the external mechanism, and fastening the fixing portion 22a by screwing a bolt inserted into a screw hole of the fixing portion to a female screw or a nut of the external mechanism. In other words, in the state where the battery module 100 is fixed to the external mechanism by the bolts, the lower end surface of the fixing portion 22a of the end plate 22, that is, the support surface 20a of the case 20 is supported by the external mechanism.

When the battery module 100 is mounted on a vehicle such as an electric vehicle or a hybrid vehicle, the external mechanism to which the battery module 100 is fixed is the vehicle body of the vehicle. Although not particularly limited, in a state where the vehicle to which the battery module 100 is fixed is placed on a horizontal road surface, the longitudinal direction (x-axis direction) and the width direction (y-axis direction) of the case 20 of the battery module 100 are substantially parallel to the horizontal direction, and the height direction (z-axis direction) of the case 20 of the battery module 100 is substantially parallel to the vertical direction. In this state, the support surface 20a of the housing 20 is substantially parallel to the horizontal plane.

The pair of side plates 23 are disposed on both sides in the width direction (y-axis direction) of the plurality of electric cells 1 constituting the battery assembly 10 with the unit frame 21 interposed therebetween. The pair of side plates 23 are metal members having a substantially rectangular plate shape, and are disposed on both sides of the housing 20 in the width direction (y-axis direction) so as to face each other. The pair of side plates 23 are substantially rectangular, and have a longitudinal direction (longitudinal direction) defined by a stacking direction (x-axis direction) of the plurality of cells 1 constituting the assembled battery 10, and a transverse direction (lateral direction) defined by a height direction (z-axis direction) of the plurality of cells 1 constituting the assembled battery 10. Both longitudinal end portions of the pair of side plates 23 are fastened to the pair of end plates 22 by fastening members such as rivets or bolts. Both ends of the pair of side plates 23 in the width direction are engaged with concave groove portions provided in the unit frame 21.

The insulating cover 24 is a plate-like member made of resin having electrical insulation such as PBT, and is disposed so as to face the upper end surface of the battery container 1a on which the cell terminals 1p, 1n of the single cells 1 are provided. The insulating cover 24 has an opening portion for exposing the upper end surfaces of the unit terminals 1p and 1n of the plurality of unit cells 1 and a partition wall for insulating the unit terminals 1p and 1n of the unit cells 1 adjacent to each other and the bus bars 2 adjacent to each other. The partition walls of the insulating cover 24 are provided so as to surround the unit terminals 1p and 1n of the single cells 1 and the bus bar 2. In addition, various electric lines connected to the battery pack 10 and the electronic circuit board are disposed on the insulating cover 24.

The electronic circuit board, not shown, is disposed between the insulating cover 24 and the module cover 25, that is, on the side of the insulating cover 24 opposite to the battery pack 10 in the height direction of the case 20, and is electrically connected to the plurality of bus bars 2 and a temperature sensor (thermistor) for detecting the temperature of the single cell 1 via a connection conductor such as a wire or a printed circuit.

The bus bar 2 is a conductor that electrically and mechanically connects the plurality of single cells 1 of the battery pack 10 and electrically and mechanically connects the battery pack 10 and the module terminals 101P, 101N.

The bus bar 2 electrically and mechanically connecting the plurality of unit cells 1 of the battery pack 10 is formed by electrically and mechanically connecting the plurality of bus bars 2A between the unit cells 1, and is welded to the upper end surfaces of the cell terminals 1p, 1n of the plurality of unit cells 1 of the battery pack 10 exposed to the opening of the insulating cover 24. By electrically connecting the cell terminal 1p of one cell 1 and the cell terminal 1n of the other cell 1 in a pair of cells 1 adjacent to each other in the stacking direction by the bus bar 2A, the assembled battery 10 in which all the cells 1 are electrically connected in series can be constructed.

The bus bars 2 connecting the battery pack 10 to the module terminals 101P, 101N are a pair of bus bars 2B arranged at both ends of the battery pack 10 in the cell stacking direction. One of the pair of bus bars 2B is electrically and mechanically connected to a cell terminal 1p of one of the pair of single cells 1 arranged at both ends of the plurality of single cells 1 in the stacking direction. The other of the pair of bus bars 2B is electrically and mechanically connected to a cell terminal 1n of the other of the pair of single cells 1 arranged at both ends in the stacking direction of the plurality of single cells 1.

One end of the pair of bus bars 2B is welded to the upper end surface of the cell terminal 1P of the cell 1, and the other end is fastened to the module terminal 101P disposed on one side of the battery assembly 10 in the cell stacking direction by a fastening member such as a rivet or a bolt. One end of the other of the pair of bus bars 2B is welded to the upper end surface of the cell terminal 1N of the cell 1, and the other end is fastened to the module terminal 101N disposed on the other side in the cell stacking direction of the battery pack 10 by a fastening member such as a rivet or a bolt.

The module cover 25 is a resin plate-like member having electrical insulation such as PBT, and is disposed at the upper end of the case 20 on the side opposite to the battery pack 10 so as to cover the insulating cover 24 and the electronic circuit board in the height direction (z-axis direction) of the case 20. A terminal cover 25a is provided at a position of the module cover 25 corresponding to the module terminals 101P and 101N so as to cover an upper portion of the module terminals 101P and 101N. The module cover 25 is fixed to the upper portion of the insulating cover 24 by engaging engagement claws 24b provided on the frame portion 24a of the insulating cover 24 with the side edges.

The battery module 100 configured as described above allows the module terminals 101P and 101N to be electrically connected to an external generator or motor via an inverter device that is a power conversion device, thereby allowing power to be transmitted and received to and from the external generator or motor via the inverter device.

Next, the structure of the bus bar 2 will be described in detail.

First, the structure of the bus bar 2A will be described in detail with reference to fig. 3 to 5. Here, fig. 3 is an enlarged cross-sectional view of the battery module 100, fig. 4 is a perspective view of the bus bar 2A, and fig. 5 is a plan view of the bus bar 2A. As described above, in the battery module 100 of the present embodiment, the structure of the bus bar 2A has the greatest feature.

As shown in fig. 3, the bus bar 2A is a connection conductor electrically and mechanically connecting one cell terminal 1p and the other cell terminal 1n of the cells 1 adjacent in the cell stacking direction, and is a dissimilar metal joined structure formed by joining a copper portion 2e containing copper and an aluminum portion 2f having aluminum.

The bus bar 2A includes a pair of connecting surface portions 2c1 and 2c2 and a bridge portion 2d connecting the pair of connecting surface portions 2c1 and 2c 2.

Of the pair of connecting surface portions 2c1 and 2c2, the connecting surface portion 2c1 to be joined to the cell terminal 1p is a flat rectangular portion formed only of the aluminum portion 2f, and is disposed on the top surface of the cell terminal 1p and joined thereto by laser welding. At the time of laser welding, the laser light is irradiated to the surface of the connecting surface portion 2c1 to join the cell terminal 1p and the connecting surface portion 2c1 so as to move around the solid portion outside the alignment hole 2z (see fig. 4 and 5) along the alignment hole 2z (with respect to the cell terminal 1 p) of the connecting surface portion 2c 1.

On the other hand, the connecting surface portion 2c2 to be joined to the negative electrode cell terminal 1n is a substantially flat rectangular portion formed by overlapping the copper portion 2e and the aluminum portion 2f in the overlapping direction (z-axis direction) of the cell terminal 1n, and the copper portion 2e is joined to the cell terminal 1n by laser welding. The copper portion 2e forms a flat rectangular flat plate portion, and a pair of arm portions 2f1 protruding in parallel to each other in pairs from the flat plate portion 2g as an upright portion are overlapped and joined to the flat plate portion. The connecting surface portion 2c2 is a dissimilar metal joint portion formed by overlapping and joining a pair of arm portions 2f1 formed of an aluminum portion 2f to a flat plate rectangular portion (the side opposite to the cell terminal 1n side) formed of a copper portion 2e, that is, a flat plate portion.

The pair of arm portions 2f1 are formed by cutting out the central portion in the short direction (y-axis direction) of the aluminum portion 2f protruding from the bridge portion 2d toward the connecting surface portion 2c2 side from the protruding end portion toward the bridge portion 2d side. A recessed portion 2f2, which is a flat concave portion recessed toward the bridge portion 2d, is formed between the pair of arm portions 2f1 so as to expose the copper portion 2e including the alignment hole 2 z.

Here, the aluminum portion 2f of the connecting surface portion 2c2 is a flat concave shaped molded body in which a rectangular flat plate is recessed toward the bridge portion 2d side, and only a part of both end portions in the short side direction (y axis direction) of the flat rectangular copper portion 2e and the bridge portion 2d side end portion of the flat rectangular copper portion 2e overlap with the copper portion 2e, and the other copper portion 2e is exposed. Therefore, the copper portion 2e of the connecting surface portion 2c2 can be joined to the cell terminal 1n by laser welding. At the time of laser welding, laser light is irradiated to the surface of the copper portion 2e of the connecting surface portion 2c2 to join the copper portion 2e of the connection surface portion 2c2 and the cell terminal 1n to each other so as to move around a solid portion outside the alignment hole 2z along the alignment hole 2z (see fig. 4 and 5) with the cell terminal 1n on the copper portion 2e of the connection surface portion 2c 2.

The joining of the copper portion 2e and the aluminum portion 2f in the connecting surface portion 2c2, that is, the joining of the flat plate portion of the copper portion 2e and the pair of arm portions 2f1 of the aluminum portion 2f, uses ultrasonic joining. In the present embodiment, the overlapping portions with the aluminum portion 2f at both ends in the short side direction (y-axis direction) of the flat rectangular copper portion 2e are defined as the joining portions 2x to be joined by ultrasonic waves. In the ultrasonic bonding, the copper portion 2e and the aluminum portion 2f can be bonded by disposing the side of the copper portion 2e opposite to the side of the aluminum portion 2f on an anvil, placing a horn on the surface of the aluminum portion 2f opposite to the side of the copper portion 2e, and applying ultrasonic vibration to the overlapping portion of the copper portion 2e and the aluminum portion 2 f. The surface of the copper portion 2e or the aluminum portion 2f or both of them subjected to ultrasonic bonding is subjected to a coating treatment such as tin plating or nickel plating.

In this manner, in the present embodiment, the joint portion 2x of the copper portion 2e and the aluminum portion 2f is formed in the connecting surface portion 2c 2. Since the cell terminal 1n is a strength member, forming the joint 2x of the copper portion 2e and the aluminum portion 2f at the connecting surface portion 2c2 can increase the rigidity of the joint 2x of the copper portion 2e and the aluminum portion 2f to increase the natural frequency. Therefore, in the present embodiment, the stress applied to the joint 2x of the copper portion 2e and the aluminum portion 2f due to vibration of the battery module 100 or the like can be reduced, and high joint strength can be ensured at the joint 2x of the copper portion 2e and the aluminum portion 2 f. Thus, in the present embodiment, the resistance of the battery module 100 against vibration and the like can be improved, and the battery module 100 with high reliability can be provided.

The bridge portion 2d is an inverted U-shaped portion formed only by the aluminum portion 2f, and is formed by a pair of flat plate portions 2g (also referred to as rising portions) 2g rising vertically or at a steep angle upward from the end of the bridge portion 2d side of the aluminum portion 2f constituting each of the connecting surface portions 2c1, 2c2, and a folded-back portion 2h (also referred to as a connecting portion) 2h connecting the pair of flat plate portions 2 g. The folded portion 2h is curved in an arch shape.

Of the portions of the copper portion 2e constituting the connecting surface portion 2c2 exposed from the aluminum portion 2f, the end portion protruding toward the side opposite to the bridge portion 2d side of the flat rectangular copper portion 2e constitutes a detection conductor for detecting voltage, and is provided as a voltage detection line joining portion 2y for joining a lead-out line (not shown) for voltage detection by soldering, ultrasonic welding, or the like. The voltage detection line joining portion 2y may be provided in the aluminum portion 2f constituting the connecting surface portion 2c 1.

For example, as shown in fig. 17 and 18, a voltage detection line bonding terminal may be drawn from the aluminum portion 2f constituting the connecting surface portion 2c1 or the copper portion 2e constituting the connecting surface portion 2c2 as a voltage detection line bonding portion 2y, and a voltage detection lead line (not shown) may be bonded to the drawn terminal by soldering, ultrasonic welding, or the like. Further, the lead terminal and the lead line may be connected by using a terminal that is crimped by an elastic member.

Next, the structure of the bus bar 2B will be described in detail with reference to fig. 6 to 9. Here, fig. 6 is an enlarged perspective view of the battery module 100 shown in fig. 1, fig. 7 is an enlarged cross-sectional view taken along line VII-VII shown in fig. 6, fig. 8 is a perspective view of the bus bar 2B connected to the module terminal 101N shown in fig. 6, and fig. 9 is a perspective view of the bus bar 2B connected to the module terminal 101P. Fig. 6 shows a state in which the terminal cover that is a part of the module cover 25 is cut away. The present embodiment is characterized in that: a fuse portion 2a, which is a portion having the smallest volume in a current path, is provided in a bus bar 2B connected to the module terminal 101N, and a space S for dropping the fused fuse 2a is provided below the fuse portion 2a of the bus bar 2B. Here, the lower side means a lower side in the vertical direction when the battery module 100 is installed so that the support surface 20a of the case 20 is horizontal. Further, the fuse portion 2a may be provided on the bus bar 2B connected to the module terminal 101P.

First, the configuration of the bus bar 2B1 connected to the module terminal 101N will be described in detail with reference to fig. 6 to 8.

The bus bar 2B1 includes a pair of connecting surface portions 2c1 and 2c2, the pair of connecting surface portions 2c1 and 2c2 being arranged in parallel in the x-axis direction, and a bridge portion 2d connecting the pair of connecting surface portions 2c1 and 2c2 so as to extend in the y-axis direction.

The connecting surface portions 2c1 and 2c2 are flat rectangular portions. The connecting surface portion 2c1 connected to the module terminal 101N is different in height position in the z-axis direction from the connecting surface portion 2c2 connected to the unit terminal 1N, and in the present embodiment, the connecting surface portion 2c1 is disposed at a position higher than the connecting surface portion 2c 2. The height positions of the connecting surface portion 2c1 and the connecting surface portion 2c2 may be the same or may be in a reverse height position relationship.

The bridge portion 2d is bent in a direction (y-axis direction) intersecting the connecting surface portions 2c1 and 2c 2. More specifically, the bridge portion 2d is formed by having a U-shaped 1 st bridge portion 2d1, a U-shaped 2 nd bridge portion 2d2 provided in parallel with the 1 st bridge portion 2d1 in the x-axis direction, and a fuse portion 2a connecting these bridge portions in the x-axis direction. The 1 st bridge part 2d1 and the 2 nd bridge part 2d2 are at the same height position in the height direction (z-axis direction) of the single cell 1.

The 1 st bridge portion 2d1 includes a pair of flat plate portions 2g1 horizontally arranged in the z-axis direction and a folded portion 2h1 (also referred to as a connecting portion) connecting the pair of flat plate portions 2g 1. The folded-back portion 2h1 is curved in an arch shape. The flat plate portion 2g1 connected to the connecting surface portion 2c1 is opposed to the flat plate portion 2g1 connected to the fuse portion 2a in the Z-axis direction, and the end portion on the side opposite to the connecting surface portion 2c1 side is connected together by the folded portion 2h 1. The end portion of the connecting surface portion 2c1 on the bridge portion 2d side is connected to the end portion of the connecting surface portion 2c1 of the flat plate portion 2g1 positioned on the lower side in the z-axis direction out of the pair of flat plate portions 2g1 via a flat plate-shaped bridge portion 2w (also referred to as an upright portion) extending (standing up) in the z-axis direction.

The 2 nd bridge portion 2d2 includes a pair of flat plate portions 2g2 horizontally arranged in the z-axis direction and a folded portion 2h2 (also referred to as a connecting portion) connecting the pair of flat plate portions 2g 2. The folded-back portion 2h2 is curved in an arch shape. The flat plate portion 2g2 connected to the connecting surface portion 2c2 is opposed to the flat plate portion 2g2 connected to the fuse portion 2a in the z-axis direction, and the end portion on the side opposite to the connecting surface portion 2c2 side is connected together by the folded portion 2h 2. The end of the flat plate portion 2g2 located on the lower side in the z-axis direction of the pair of flat plate portions 2g2 on the side of the connecting surface portion 2c2 is connected to the end of the bridge portion 2d of the connecting surface portion 2c2 so as to extend horizontally in the y-axis direction toward the connecting surface portion 2c 2.

The fuse portion 2 a-side end portion of the flat plate portion 2g1 located on the upper side in the z-axis direction out of the pair of flat plate portions 2g1 and the fuse portion 2 a-side end portion of the flat plate portion 2g2 located on the upper side in the z-axis direction out of the pair of flat plate portions 2g2 are connected together via the fuse portion 2 a. The current path between the 1 st bridge part 2d1 and the 2 nd bridge part 2d2 is constituted only by the fuse part 2a having a smaller current-carrying area than the current-carrying areas of the 1 st bridge part 2d1 and the 2 nd bridge part 2d2, and becomes a current path of a minimum volume in the bus bar 2B 1. Therefore, when an excessive current flows to the bus bar 2B1, the current density in the fuse section 2a and the temperature due to heat generation become maximum in the bus bar 2B 1. When the temperature due to heat generation exceeds the melting point temperature of the material of the fuse portion 2a, the fuse portion 2a is fused at the earliest in the bus bar 2B 1. This can cut off the current path of bus bar 2B 1.

Bus bar 2B1 is a dissimilar metal joined structure formed by joining copper portion 2e containing copper and aluminum portion 2f having aluminum. Since the dissimilar metal bonding uses composite (クラッド) bonding, the bus bar 2B1 may be referred to as a composite bus bar (クラッド バ ス バ ー). In the present embodiment, the connecting surface portions 2c1, 2c2 and the bridge portion 2w are copper portions 2e, and the bridge portion 2d is an aluminum portion 2 f. A part of the bridge portion 2d, for example, the flat plate portion 2g1 located on the upper side in the z-axis direction out of the pair of flat plate portions 2g1, the flat plate portion 2g2 located on the upper side in the z-axis direction out of the pair of flat plate portions 2g2, and the fuse portion 2a may be an aluminum portion 2f, and the remaining portion may be a copper portion 2 e.

In the present embodiment, the folded-back portion 2h is provided in relation to the bus bar accommodating space of the insulating cover 24, but the folded-back portion 2h may be omitted when the bus bar accommodating space is large.

In addition, in the case where the module terminal 101N is designed to have the same height position as the unit terminal 1N, the bridge portion 2w may be omitted.

The gap S for dropping the fused fuse portion 2a is defined by the single cell 1 and the case 20. Specifically, the space S below the fuse portion 2a is a space inside the case 20 defined by the cell terminals 1p and 1n of the single cell 1, the battery container 1a, and the cell frame 21 of the case 20, faces the lower surface of the bus bar 2B1 facing the single cell 1, has a depth equal to or greater than the height of the cell terminal 1n in the direction perpendicular to the support surface 20a of the case 20 (z-axis direction), and has a sufficiently large volume compared with the volume of the fuse portion 2 a. When an excessive current flows to the bus bar 2B1 to melt the metal material constituting the fuse portion 2a, the molten metal material of the fuse portion 2a falls into the space S below the fuse portion 2a by gravity. This prevents a new current path from being formed between the positive cell terminal 1p and the negative cell terminal 1n of the single cell 1 by the molten metal material, and improves the safety of the battery module 100.

Further, according to the configuration of the bus bar 2B1 of the present embodiment, since the fuse portion 2a can be disposed at a position distant from the cell terminal 1n, it is possible to more reliably prevent a new current path from being formed between the positive cell terminal 1p and the negative cell terminal 1n of the single cell 1 by the molten metal material, and to further improve the safety of the battery module 100.

Next, the configuration of bus bar 2B2 connected to module terminal 101P will be described in detail with reference to fig. 9.

The bus bar 2B2 includes a pair of connecting surface portions 2c1 and 2c2 arranged in parallel in the x-axis direction, and a bridge portion 2d connecting the pair of connecting surface portions 2c1 and 2c 2.

The connecting surface portions 2c1 and 2c2 are flat rectangular portions. The connecting surface portion 2c1 connected to the module terminal 101P is different in height position in the z-axis direction from the connecting surface portion 2c2 connected to the unit terminal 1P, and in the present embodiment, the connecting surface portion 2c1 is disposed at a position higher than the connecting surface portion 2c 2. The height positions of the connecting surface portion 2c1 and the connecting surface portion 2c2 may be the same or may be in a reverse height position relationship.

The bridge portion 2d is a flat rectangular portion bent (raised) in a direction (z-axis direction) intersecting the connecting surface portions 2c1 and 2c2, and may be referred to as a raised portion.

Bus bar 2B2 is a dissimilar metal joined structure formed by joining copper portion 2e containing copper and aluminum portion 2f having aluminum. Since the dissimilar metal is bonded by composite bonding, the bus bar 2B2 may be referred to as a composite bus bar. In the present embodiment, the connecting surface portion 2c1 is a copper portion 2e extending to the bridge portion 2d, and the connecting surface portion 2c2 is an aluminum portion 2f extending to the bridge portion 2 d.

[ embodiment 2]

Fig. 10 to 12 are views showing embodiment 2 of the present invention.

The present embodiment is for securing high bonding strength at the bonding portion 2x of the copper portion 2e and the aluminum portion 2f of the bus bar 2A, as in embodiment 1, but is different from embodiment 1 in structure. Here, fig. 10 is a perspective view of the bus bar 2A, fig. 11 is a plan view of the bus bar 2A, and fig. 12 is a side view of the bus bar 2A. Since the configuration of the battery module other than the bus bar 2A is the same as that of embodiment 1, only the portions different from embodiment 1 will be described below.

The bus bar 2A is a connection conductor electrically and mechanically connecting one cell terminal 1p and the other cell terminal 1n of the cells 1 adjacent to each other in the cell stacking direction, and is a dissimilar metal joined structure formed by joining a copper portion 2e containing copper and an aluminum portion 2f having aluminum.

As shown in fig. 10, the bus bar 2A includes a pair of connecting surface portions 2c1 and 2c2 and a bridge portion 2d connecting the pair of connecting surface portions 2c1 and 2c 2.

Of the pair of connecting surface portions 2c1 and 2c2, the connecting surface portion 2c1 to be joined to the cell terminal 1p is a flat rectangular portion formed only of the aluminum portion 2f, and is disposed on the top surface of the cell terminal 1p and joined thereto by laser welding. At the time of laser welding, the cell terminal 1p and the connecting surface portion 2c1 are joined by irradiating laser light to the surface of the connecting surface portion 2c1 so as to be moved around the solid portion outside the alignment hole 2z (see fig. 10 and 11) along the alignment hole 2z (with respect to the cell terminal 1 p) of the connecting surface portion 2c 1.

On the other hand, the connecting surface portion 2c2 to be joined to the negative electrode cell terminal 1n is a flat rectangular portion formed only of the copper portion 2e, and is arranged on the top surface of the cell terminal 1n and joined thereto by laser welding. At the time of laser welding, the laser light is irradiated to the surface of the connecting surface portion 2c2 to join the unit terminal 1n and the connecting surface portion 2c2 so as to move around the solid portion outside the alignment hole 2z (see fig. 10 and 11) along the alignment hole 2z (with respect to the unit terminal 1n) of the connecting surface portion 2c 2.

The bridge portion 2d is an inverted U-shaped portion formed of a copper portion 2e and an aluminum portion 2f, and includes a flat plate portion 2g (also referred to as an upright portion), a flat plate portion 2v, and a folded-back portion 2h (also referred to as a connecting portion), the flat plate portion 2g being upright vertically upward or at a steep angle from the end of the aluminum portion 2f on the side of the bridge portion 2d constituting the connecting surface portion 2c1, the flat plate portion 2v facing the flat plate portion 2g in the x-axis direction, the folded-back portion 2h connecting the flat plate portion 2g and the flat plate portion 2 v.

The folded portion 2h is curved in an arch shape. The flat plate portion 2g and the folded portion 2h are constituted by an aluminum portion 2f, and the flat plate portion 2v is constituted by joining a copper portion 2e and the aluminum portion 2 f. The flat plate portion 2v is a dissimilar metal joint portion where the copper portion 2e and the aluminum portion 2f are overlapped and joined together. The flat plate portion 2v of the present embodiment corresponds to one rising portion described in claims, and the flat plate portion 2g corresponds to the other rising portion described in claims.

The flat plate portion 2g has a rectangular flat plate cut out at the center in the y-axis direction, and extends upward in the z-axis direction while being bifurcated at both ends in the y-axis direction from the end of the bridge portion 2d on the connecting surface portion 2c 1. Similarly, the folded portion 2h is cut away at the center in the y-axis direction, and both ends in the y-axis direction extend toward the flat plate portion 2 v. Thereby, the inside of the bridge portion 2d is exposed, particularly, the inside of the y-axis direction center portion. That is, the flat plate portion 2g and the folded portion 2h are provided with notches for exposing the flat plate rectangular portion 2e 1.

The flat plate portion 2v is a portion in which a flat plate rectangular portion 2e1 (1 st flat plate rectangular portion) rising upward perpendicularly or at a steep angle from the end on the bridge portion 2d side of the copper portion 2e constituting the connecting surface portion 2c2 and the inner surface of a flat plate rectangular portion 2f3 (2 nd flat plate rectangular portion) extending downward in the z-axis direction from the folded-back portion 2h overlap each other in the x-axis direction. That is, the inner surfaces of the 2 members bent in the shape of a hook are overlapped with each other. The flat plate rectangular portion 2f3 is formed continuously to the folded portion 2h, and the side surface facing the flat plate portion 2g is overlapped and joined to the side surface of the flat plate rectangular portion 2e1 on the side of the connecting surface portion 2c 2.

In the present embodiment, the flat rectangular portion 2f3 is lowered beyond the upper end of the flat rectangular portion 2e1 with respect to the flat rectangular portion 2e1 that is raised, and overlaps in the x-axis direction. This structure may be provided on the flat plate portion 2g side, and in this case, the following shape: the flat rectangular portion on the copper portion 2e side descends beyond the upper end of the flat rectangular portion of the aluminum portion with respect to the flat rectangular portion standing on the aluminum portion 2f side, and overlaps with the flat rectangular portion in the x-axis direction.

As in embodiment 1, ultrasonic bonding is used for bonding the copper portion 2e and the aluminum portion 2 f. In the present embodiment, the y-axis direction center portion of the overlapping portion of the flat plate rectangular portion 2e1 and the flat plate rectangular portion 2f3 is defined as a joint portion 2x of the copper portion 2e and the aluminum portion 2 f. At the time of ultrasonic bonding, the anvil is placed on one surface of the y-axis direction central portion of the flat plate rectangular portion 2e1 on the side opposite to the flat plate rectangular portion 2f3 side and the y-axis direction central portion of the flat plate rectangular portion 2f3 on the side opposite to the flat plate rectangular portion 2e1 side, and a horn is placed on the other surface to apply ultrasonic vibration to the overlapping portion of the flat plate rectangular portion 2e1 and the flat plate rectangular portion 2f3, whereby the copper portion 2e and the aluminum portion 2f can be bonded. The surface of the copper portion 2e or the aluminum portion 2f or both of them subjected to ultrasonic bonding is subjected to a coating treatment such as tin plating or nickel plating.

In this way, in the present embodiment, the joint portion 2x between the copper portion 2e and the aluminum portion 2f is formed in the bridge portion 2 d. In the bridge portion 2d, the flat plate rectangular portion 2e1 and the flat plate rectangular portion 2f3 are bent in a hook shape, and inner faces thereof are joined to each other in an opposed manner. According to such a joint structure, when stress occurs in the direction of tearing the copper portion 2e and the aluminum portion 2f, the joint of the joint 2x becomes the direction of pressure contact, and the bending elastic force of the bent portions of the respective parts can be made to act on the joint 2x of the copper portion 2e and the aluminum portion 2f as a reaction force in the direction opposite to the direction of the stress acting on the joint 2x of the copper portion 2e and the aluminum portion 2f, so that the stress acting on the joint 2x of the copper portion 2e and the aluminum portion 2f can be reduced.

Thus, for example, in the case where stress occurs in the direction in which the connecting surface portions 2c1 and 2c2 are spaced apart in the x-axis direction, a force in the direction in which the flat plate rectangular portions 2e1 of the copper portion 2e and the flat plate rectangular portions 2f3 of the aluminum portion 2f are pressed against each other can be generated. Thus, it is possible to ensure high bonding strength at the joint 2x of the copper portion 2e and the aluminum portion 2 f. As a result, in the present embodiment, as in embodiment 1, the resistance of the battery module against vibration and the like can be improved, and a highly reliable battery module can be provided.

The voltage detection line joint portion may be provided on the surface of either one of the connection surface portions 2c1, 2c 2. Further, a voltage detection line connection terminal may be drawn from either of the connection surface portions 2c1 and 2c2, and a voltage detection lead line (not shown) may be connected to the drawn terminal by soldering, ultrasonic welding, or the like. Further, the lead terminal and the lead line may be connected by using a terminal that is crimped by an elastic member.

[ embodiment 3]

Fig. 13 to 16 are views showing embodiment 3 of the present invention.

The present embodiment is for securing high bonding strength at the bonding portion 2x of the copper portion 2e and the aluminum portion 2f of the bus bar 2A, as in embodiment 1, but is different from embodiment 1 in structure. Here, fig. 13 is a perspective view of the bus bar 2A, fig. 14 is a plan view of the bus bar 2A, fig. 15 is a side view of the bus bar 2A, and fig. 16 is a perspective view of the bus bar 2A provided on the unit terminal. Since the configuration of the battery module other than the bus bar 2A is the same as that of embodiment 1, only the portions different from embodiment 1 will be described below.

As shown in fig. 16, the bus bar 2A is a connection conductor electrically and mechanically connecting one cell terminal 1p and the other cell terminal 1n of the cells 1 adjacent in the cell stacking direction, and is a dissimilar metal joined structure formed by joining a copper portion 2e containing copper and an aluminum portion 2f having aluminum.

As shown in fig. 13, the bus bar 2A includes a pair of connecting surface portions 2c1 and 2c2 and a bridge portion 2d connecting the pair of connecting surface portions 2c1 and 2c 2.

Of the pair of connecting surface portions 2c1 and 2c2, the connecting surface portion 2c1 to be joined to the cell terminal 1p is a flat rectangular portion formed only of the aluminum portion 2f, and is disposed on the top surface of the cell terminal 1p and joined thereto by laser welding. At the time of laser welding, the laser light is irradiated to the surface of the connecting surface portion 2c1 to join the cell terminal 1p and the connecting surface portion 2c1 so as to move around the solid portion outside the alignment hole 2z (see fig. 13 and 14) along the alignment hole 2z (with respect to the cell terminal 1 p) of the connecting surface portion 2c 1.

On the other hand, the connecting surface portion 2c2 to be joined to the negative electrode cell terminal 1n is a substantially flat rectangular portion formed by forming Contraband-shaped portions of both end portions of the copper portion 2e in the longitudinal direction (x-axis direction), sandwiching the aluminum portion 2f in Contraband-shaped form overlapped on the copper portion 2e, and further overlapping in the overlapping direction (z-axis direction) with the cell terminal 1n, and joining the copper portion 2e to the cell terminal 1n by laser welding the connecting surface portion 2c 2. That is, the connection surface portion 2c2 is a dissimilar metal joint portion in which a flat plate concave portion recessed toward the bridge portion 2d side of the aluminum portion 2f is superimposed on a flat plate rectangular portion (the side opposite to the cell terminal 1n side) formed of the copper portion 2 e.

The aluminum portion 2f of the connecting surface portion 2c2 has a pair of arm portions 2f 1. The pair of arm portions 2f1 are formed by cutting out the widthwise (y-axis direction) central portion of the aluminum portion 2f protruding from the bridge portion 2d toward the connecting surface portion 2c2 side from the protruding end portions toward the bridge portion 2d side. A recessed portion 2f2, which is a flat concave portion recessed toward the bridge portion 2d, is formed between the pair of arm portions 2f1 so as to expose the copper portion 2e including the alignment hole 2 z.

The copper portion 2e of the connecting surface portion 2c2 has a base portion 2e3 and a claw portion 2e2 respectively opposed to the pair of arm portions 2f1 on one side and the other side in the overlapping direction with the arm portions. The base portions 2e3 of the copper portion 2e are provided at positions spaced apart from each other in the width direction at both ends in the longitudinal direction as a pair. The hook 2e2 of the copper portion 2e is arranged at the end portions on both sides in the longitudinal direction at a position where the central portion in the width direction is lifted from the base 2e3 toward the overlapping direction side, that is, the side spaced apart from the unit terminal 1n, and is formed with a space into which the arm 2f1 can be inserted between the hook and the base 2e 3.

Here, the aluminum portion 2f of the connecting surface portion 2c2 is a flat concave shaped molded body in which a rectangular flat plate is recessed toward the bridge portion 2d side, and only a part of both end portions in the width direction (y-axis direction) of the flat rectangular copper portion 2e and the end portion on the bridge portion 2d side of the flat rectangular copper portion 2e overlap with the copper portion 2e, and the other copper portion 2e is exposed. Therefore, the copper portion 2e of the connecting surface portion 2c2 can be joined to the cell terminal 1n by laser welding. At the time of laser welding, laser light is irradiated to the surface of the copper portion 2e of the connecting surface portion 2c2 to join the copper portion 2e of the connection surface portion 2c2 and the cell terminal 1n to the surface of the copper portion 2e of the connection surface portion 2c2 so as to move around the solid portion outside the alignment hole 2z along the alignment hole 2z (see fig. 13 and 14) with the cell terminal 1 n.

The joining of the copper portion 2e and the aluminum portion 2f (the pair of arm portions 2f1) in the connecting surface portion 2c2 is ultrasonic joining. In the present embodiment, the joining portion 2x to be ultrasonically joined is defined as an overlapping portion of the aluminum portion 2f at the two widthwise (y-axis) ends Contraband of the flat plate portion of the flat plate-shaped rectangular copper portion 2e, that is, an overlapping portion of the arm portion 2f1 of the aluminum portion 2f and the claw portion 2e2 of the copper portion 2 e. In the ultrasonic bonding, the aluminum portion 2f side of the copper portion 2e is arranged on an anvil, a horn is placed on the surface of the aluminum portion 2f on the side opposite to the copper portion 2e side, and ultrasonic vibration is applied to the overlapping portion of the copper portion 2e and the aluminum portion 2f, whereby the copper portion 2e and the aluminum portion 2f can be bonded. The surface of the copper portion 2e or the aluminum portion 2f or both of them subjected to ultrasonic bonding is subjected to a coating treatment such as tin plating or nickel plating.

In this way, in the present embodiment, the aluminum portion 2f is overlapped so as to be sandwiched between the upper and lower portions of the copper portion 2e formed in Contraband, and the joint portion 2x is formed between the arm portion 2f1 and the claw portion 2e 2. The copper portion 2e is bonded to the cell terminal 1n, which is also made of copper material, by laser, and since copper is bonded to each other, a strong bond can be achieved. Therefore, when an upward external pressure is applied to the aluminum portion 2f, the joint of the joint portion 2x becomes a direction in which the joint becomes stronger, and when a downward external pressure is applied to the aluminum portion 2f, the unit terminal 1n below the aluminum portion 2f becomes a support, so the joint portion 2x does not bend downward. Thus, it is possible to ensure high bonding strength at the joint 2x of the copper portion 2e and the aluminum portion 2 f. As a result, in the present embodiment, as in embodiment 1, the resistance of the battery module against vibration and the like can be improved, and a highly reliable battery module can be provided.

While the embodiments of the present invention have been described in detail, the present invention is not limited to the embodiments, and various design changes may be made without departing from the spirit of the present invention described in the claims. For example, the embodiments are described in detail to explain the present invention in a manner easy to understand, and are not necessarily limited to all configurations described. Note that a part of the structure of one embodiment may be replaced with the structure of another embodiment, or the structure of one embodiment may be added to the structure of another embodiment. Further, addition, deletion, and replacement of another configuration may be performed on a part of the configuration of each embodiment.

Description of the symbols

1 … single cell

1p … cell terminal

1n … cell terminal

2 … bus bar

2A … bus bar

2B1(2B) … bus

2B2(2B) … bus

2a … fuse part

2c1 … connecting face

2c2 … connecting face

2d … bridge part

2d1 … bridge part 1

2d2 … bridge part 2

2e … copper part

2f … aluminum part

2g … Flat plate part

2h … turn-back part

2v … Flat plate part

2w … bridge part

2x … joint

2y … Voltage detection line junction

2z … alignment hole

10 … battery pack

100 … battery module

20 … casing

20a … bearing surface

101P … module terminal

101N … module terminal

S … void.