JP2002246004A - Battery connection structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a battery connection structure with a plurality of battery modules connected in series, allowing a large current to be taken at low loss, without impairing the welding performance of a connection member to be used in a connection in the radial direction. SOLUTION: The connection member for the battery connection structure, having at least two cells arranged in parallel with one polarity reversed to the other and connected in series to each other via the connection member comprises a positive electrode jointing part to be connected to a positive electrode of one cell, a negative electrode jointing part to be connected to a metal case serving as a negative electrode of the other cell and jointing member for jointing the positive electrode jointing part and the negative electrode jointing part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery connection structure, and more particularly, to a structure in which unit cells or a plurality of unit cells formed by connecting a plurality of unit cells in the axial direction are juxtaposed with opposite polarities. More specifically, the present invention relates to a battery connecting structure used for the purpose of extracting a large current with low loss, particularly a structure in which different electrodes of two batteries located at the ends are connected in series.

[0002]

2. Description of the Related Art In recent years, demand for nickel-hydrogen secondary batteries and the like as drive power sources for various electric tools, electric assist bicycles, and electric vehicles has been increasing. In that case, for example, when used as a drive source for an electric vehicle, 1
An output voltage of 00 to 300 V is required.

[0003] Therefore, usually, a plurality of unit cells are connected in series in the axial direction to assemble a rod-shaped battery module, and a plurality of such battery modules are juxtaposed in the radial direction, and are attached to the end of each module. It is common to connect different poles of unit cells located in series with each other to form a battery connection structure as a whole. Specifically, a battery connection structure 1 as shown in FIG. 5 can be given. That is, the battery connection structure is configured by connecting the battery modules A and B in series. The battery module A has, for example, five unit cells A1 to A5 connected in series in the axial direction via, for example, a connection member 7, and the battery module B has the same types of unit cells B1 to B5 as the battery module A. Are connected in series in the axial direction. The sealing plate 8 also serving as the positive electrode of the unit cell A1 at the end of the module A and the metal case 9 also serving as the negative electrode of the unit cell B5 at the end of the battery module B are connected in series by the connecting member 2.

As shown in FIG. 6, a connecting member 2 for connecting two batteries in a radial direction has connecting portions 2a and 2b formed at both ends thereof, and the connecting portions 2a and 2b are used for welding. And slits 3 and 4 for reducing reactive current, and projections 5 and 6 for projection welding formed on both sides of these slits 3 and 4. Then, the projections 5 and 6 are brought into contact with the respective electrodes of the cells A1 and B5 to be connected, and series welding utilizing resistance heat generation (resistance welding).
Was connected by welding.

[0005]

Conventionally, connection members to which such resistance welding can be applied include nickel materials and NPs.
S (Nickel Plated Steel) material or the like is used, but in order to provide the above-mentioned projections on such a material by, for example, press forming, the thickness of the member is made extremely thin (for example, 0.1 to 0.5 mm). )There is a need.

[0006] However, when the thickness of the member is reduced, the resistance value of the connection portion increases, and as a result, the loss when the current is extracted from the battery connection structure increases. The problem arises that it is not suitable for the use of the above. On the other hand, for example, the connection member may be formed of a material having a low resistance value, such as copper. However, in this case, since connection by resistance welding is difficult, it is necessary to consider another connection method. However, since separate equipment and facilities are required in accordance with the coupling method, the cost is increased.

The present invention solves the above-mentioned problems of the conventional battery connection structure, and does not impair the weldability of connection members for forming the battery connection structure, and does not require the installation of new equipment or equipment. It is another object of the present invention to provide a battery connection structure capable of extracting a large current with low loss.

[0008]

According to the present invention, in order to achieve the above object, at least two unit cells are juxtaposed with opposite polarities and connected in series by a connecting member. In a battery connection structure comprising: the connection member, a positive electrode coupling portion connected to the positive electrode of one of the cells,
There is provided a battery connection structure including a negative electrode connecting portion connected to a metal case also serving as a negative electrode of the other unit cell, and a connecting member connecting the positive electrode connecting portion and the negative electrode connecting portion.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of a battery connection structure according to the present invention will be described below in detail with reference to FIGS. FIG. 1 shows an example of a configuration of a connection member used for radial connection of a cylindrical unit cell in a battery connection structure of the present invention,
The connecting member 10 includes a plate-shaped connecting member 11, and a positive electrode connecting portion 12 and a negative electrode connecting portion 13 provided at both ends 11 a and 11 b of the connecting member 11, respectively.

The connecting member 11 may be a member conventionally used for electrical connection between cells, for example, a bus bar. One end 11a of the connecting member 11 has an opening 1
1c is formed, and a positive electrode terminal (not shown) of the unit cell can protrude from the opening 11c. The positive electrode coupling portion 12 is connected by welding to the positive electrode side of the unit cell shown in FIG. 2, and for example, as shown in FIG.
It is preferably formed in a dish-like body composed of 2a and dish portion 12b. The flange portion 12a is fixedly welded to the periphery of the opening 11c at one end 11a of the connecting member 11. In order to improve the weldability at that time, a plurality of, for example, four projection welding projections 14 may be formed along the circumferential direction.

The plate portion 12b has its upper surface 12d welded to a sealing plate 8 (FIG. 2) also serving as a positive electrode terminal of the unit cell.
An opening 12e for projecting a positive electrode terminal (not shown) is formed at the center. On the upper surface 12d, the collar 1
A projection 15 for projection welding is formed similarly to 2a. On the other hand, the negative electrode coupling portion 13 is formed in a bottomed cylindrical shape, that is, a cup-shaped body as shown in the figure, and the bottom portion 13 a is welded and fixed to the other end portion 11 b of the connecting member 11. Then, the side wall 13b is externally fitted to the metal case bottom 9 also serving as the negative electrode of the unit cell. This negative electrode coupling portion 13
The bottom 13a, the other end 11b of the connecting member, and the inner peripheral surface of the side wall 13b of the negative electrode coupling portion 13 and the metal case 9 of the unit cell are connected by, for example, resistance welding. For this reason, it is preferable that notch holes 16 and 17 for reducing reactive current are formed in the bottom portion 13a and the side wall 13b, respectively.

In the connecting member 10, the material constituting each part is not particularly limited, but for example, nickel-plated iron or the like is preferable. Then, the thickness of the connecting member 10 is increased, for example, 1.5 m
m or more, more preferably about 2.0 to 3.0 mm, the resistance value of the connection member is reduced, and it is possible to reduce the loss when extracting a large current from the battery connection structure. Further, by increasing the thickness of the connection member, the rigidity of the connection portion when the battery connection structure is assembled is improved,
It is possible to prevent breakage when installed in a place that is easily affected by external vibration.

A battery connection structure 20 using the above-described connection member 10 and connecting the batteries A1 and B5 at the ends of battery modules A and B similar to those shown in FIG. Is shown in FIG. 2 (only the ends are shown). That is, the positive electrode coupling portion 12 and the negative electrode coupling portion 13 of the connection member 10 are connected to the end faces of the cells A1 and B5, respectively. Specifically, the bottom surface 12d of the plate portion 12b of the positive electrode coupling portion 12 of the connection member 10 abuts on the sealing plate 8 also serving as the positive electrode terminal of the unit cell A1, and a welding electrode (not shown) is connected to the opening 11c of the connection member 11. ) Is inserted to connect the bottom surface 12a and the sealing plate 8 by welding.

On the other hand, the side wall 13b of the negative electrode coupling portion 13 of the connecting member 10 is connected to the metal case bottom 9 serving also as the negative electrode of the unit cell B5.
And a welding electrode (not shown) from the outside of the side wall 13b.
To weld the side wall 13b to the metal case bottom 9 by welding. Thus, the battery connection structure 20 is manufactured. 3 and 4 show another configuration of the connection member used for the connection portion of the battery connection structure of the present invention, and the same components as those in FIG. 1 are denoted by the same reference numerals. The connection member 30 is similar to the connection member 10 in that the dish-shaped positive electrode coupling portion 12 is fixed to the periphery of the opening 31c of the one end portion 31a of the connection member 31. However, the other end portion 31b is cup-shaped. Instead of fixing the negative electrode coupling portion 13 of FIG. 4, a circular concave portion 31d having an inner diameter substantially equal to the outer diameter of the metal case bottom 9 is formed in a portion fitted to the metal case bottom 9 of the unit cell as shown in FIG. Are formed.

The circular recess 31d is externally fitted to the bottom of the metal case, and is fixed to the bottom of the metal case by welding from the back surface of the circular recess 31d. By forming the circular recess 31d in the connecting member 30 in this manner, the thickness of the connecting member 30 is reduced, and the weldability with the metal case bottom 9 is improved. Further, since there is no need to separately weld other members, the number of parts is reduced, which contributes to cost reduction. The notch 32 for reducing the reactive current and the projection 3 for projection welding are also provided in the circular concave portion 31d, similarly to the negative electrode coupling portion 13 in FIG.
3 are formed.

The use of such connecting members 10 and 30 has the following advantages. That is, the first
In addition, a metal having good resistance weldability, such as nickel-plated iron, which has been conventionally used as a connecting member, can be used as it is. Secondly, since the connecting member is not directly welded to the unit cell, but is connected to the unit cell via the positive electrode connecting portion 13 and the negative electrode connecting portion 12, the thickness of the connecting member can be increased, , And as a result, the loss at the time of extracting a large current can be reduced. Third, since the thickness of the connecting member can be increased, the rigidity of the connecting portion is improved, and the connecting structure can sufficiently withstand vibration and the like. Fourthly, since the conventional welding condition of the battery connection structure can be used with almost no change in the welding conditions, the welding strength and welding stability can be sufficiently ensured, and further, new facilities and equipment, etc. Since it is not necessary, an increase in manufacturing cost can be avoided.

[0017]

As described above, in the battery connection structure of the present invention, the conventional welding conditions for the connection portion can be maintained as they are, and the thickness of the connection member can be freely set. The resistance can be reduced, and as a result, the loss at the time of extracting a large current can be reduced.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing one embodiment of a connection member used for a connection portion of a battery connection structure of the present invention.

FIG. 2 is a conceptual diagram showing a state in which battery modules are connected using the connection member of FIG. 1;

FIG. 3 is an exploded perspective view showing another embodiment of the connection member used for the connection portion of the battery connection structure of the present invention.

FIG. 4 is a cross-sectional view taken along line IV-IV of a connecting member constituting the connecting member of FIG. 3;

FIG. 5 is a perspective view of a conventional battery connection structure.

FIG. 6 is a plan view of a connection member used for a conventional battery connection structure.

[Explanation of symbols]

 8 Sealing plate (Positive electrode) 9 Metal case bottom (Negative electrode) 10,30 Connecting member 11,31 Connecting member 11c, 31c Opening 12 Positive electrode coupling part 12a Collar part 12b Plate part 12e Opening 13 Negative electrode coupling part 13a Bottom part 13b Side wall 14,15 , 33 Projection for projection welding 16,17,32 Notch 31d recess (negative electrode joint)

Claims (6)

[Claims] 1. A battery connection structure in which at least two unit cells are juxtaposed with opposite polarities and connected in series by a connecting member, wherein the connecting member is a positive electrode of one of the unit cells. And a connecting member for connecting the positive electrode connecting portion and the negative electrode connecting portion to each other, and a negative electrode connecting portion connected to a metal case also serving as a negative electrode of the other unit cell. Battery connection structure. 2. The method according to claim 1, wherein the positive electrode coupling portion is a dish-shaped body.
4. The battery connection structure according to 1. 3. The battery connection structure according to claim 1, wherein the negative electrode coupling portion is a cup-shaped body fitted to the bottom of the metal case of the unit cell. 4. The battery connecting structure according to claim 1, wherein the negative electrode connecting portion is a concave portion formed in the connecting member. 5. The battery connection structure according to claim 1, wherein the connection member is formed of a nickel-plated iron material. 6. The battery connection structure according to claim 1, wherein the thickness of the connection member is 1.5 mm or more.