KR20130114304A - Welding device for improved weldability of bus bar - Google Patents

Abstract

PURPOSE: A welding device for improving the efficiency of welding a busbar is provided to improve the efficiency of welding the busbar and an electrode terminal, thereby improving the safety of a battery module assembly. CONSTITUTION: A welding device (300) for improving the efficiency of welding a busbar includes a horn (310), an anvil (320), and a booster (330). The horn welds the busbar on an electrode terminal by directly applying vibration on the busbar and includes horn tips corresponding to minute holes for forming the minute holes of an embossing structure in a welding process. The anvil fixes the bottom end portion of the busbar, thereby transmitting the vibration to the busbar. The booster regulates the intensity of the vibration.

Description

Technical Field [0001] The present invention relates to a welding device for improving the weldability of a bus bar,

The present invention relates to a welding apparatus for improving the weldability of a bus bar, and more particularly to an apparatus for welding an electrode terminal and a bus bar of a battery module assembly, wherein direct vibration is applied to the bus bar, A horn including horn tips corresponding to the fine holes on the surface facing the bus bar so that the embossed fine holes can be formed in the bus bar during the welding process; An anvil for fixing the lower end of the bus bar to transmit the generated vibration to the bus bar; And a booster for adjusting the increase / decrease of the vibration; To a welding apparatus.

BACKGROUND ART [0002] In recent years, rechargeable secondary batteries have been widely used as energy sources for wireless mobile devices. The secondary battery is also attracting attention as a power source for an electric vehicle (EV) and a hybrid electric vehicle (HEV), which are proposed as solutions for the air pollution of existing gasoline vehicles and diesel vehicles using fossil fuels .

In a small mobile device, one or two or more battery cells are used per device, while a middle- or large-sized battery module such as an automobile is used as a middle- or large-sized battery module in which a plurality of battery cells are electrically connected due to the necessity of a large-

Since the middle- or large-sized battery module is preferably manufactured with a small size and weight, a prismatic battery, a pouch-type battery, and the like, which can be stacked with high degree of integration and have a small weight to capacity ratio, are mainly used as the battery cells of the middle- or large-sized battery module. In particular, a pouch-shaped battery using an aluminum laminate sheet or the like as an exterior member has recently attracted a lot of attention due to its advantages such as small weight, low manufacturing cost, and easy shape deformation.

1 is a perspective view schematically showing a representative pouch-type battery cell. The pouch-type battery cell 10 of FIG. 1 has a structure in which two electrode terminals 11 and 12 protrude from each other to protrude from an upper end and a lower end of the battery main body 13. The exterior member 14 is composed of two upper and lower units, and both side surfaces 14b and upper and lower portions 14a, which are mutually contacting portions, with electrode assemblies (not shown) mounted on an accommodating portion formed on an inner surface thereof. The battery cells 10 are made by attaching 14c). The exterior member 14 has a laminate structure of a resin layer / metal foil layer / resin layer, and can be attached by mutually fusion bonding the resin layer by applying heat and pressure to both side surfaces 14b and the upper and lower ends 14a and 14c which are in contact with each other. In some cases, the adhesive may be attached using an adhesive.

Since both side surfaces 14b are in direct contact with the same resin layer of the upper and lower exterior members 14, uniform sealing is possible by melting. On the other hand, since the electrode terminals 11 and 12 protrude from the upper end 14a and the lower end 14c, the sealing property is improved in consideration of the thickness of the electrode terminals 11 and 12 and the heterogeneity with the material of the exterior member 14. Heat-sealing is carried out in the state which interposed the film-shaped sealing member 16 between the electrode terminals 11 and 12 so that it may be made.

In the case of constructing a medium-large battery module using a plurality of battery cells as described above, the electrode terminals of the battery cells are interconnected by welding for the mechanical fastening and electrical connection thereof, and are generally coupled using a bus bar.

On the other hand, the medium-large battery module is used as a power source of an electric vehicle, the battery module built in such a device is easily exposed to external shock, vibration, etc., a structure having high safety is required. Particularly, in a battery module, when a portion electrically connecting an electrode terminal of a battery cell and a bus bar is not firmly welded, the welded portion may be separated due to continuous vibration or impact, , And excellent weldability between the electrode terminal and the bus bar is required.

Generally, the electrode terminal and the bus bar are welded by ultrasonic welding.

Specifically, a bus bar is placed in contact with the electrode terminal, and the electrode bar is pressurized by an ultrasonic welder. At this time, the ultrasonic vibration is transmitted to the electrode terminal, and the electrode terminal is welded to the bus bar due to the friction heat generated by the vibration energy.

However, since the electrode terminal and the bus bar are formed in a smooth plane, the adhesion may be deteriorated during the ultrasonic welding to the electrode terminal, and the welding quality of the bus bar may be uneven.

Therefore, there is a high need for a technology that can fundamentally solve these problems.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-described problems of the prior art and the technical problems required from the past.

It is an object of the present invention to provide a welding apparatus for forming embossed fine holes in a bus bar welded to an electrode terminal.

Welding apparatus according to the present invention for achieving this object, as a device for welding the electrode terminal and the bus bar of the battery module assembly,

A bus bar is fused to the electrode terminal by applying a direct vibration to the bus bar and the bus bar is welded to the bus bar in order to form embossed fine holes in the bus bar, (horn);

An anvil for fixing the lower end of the bus bar to transmit the generated vibration to the bus bar; And

A booster for adjusting the increase / decrease of the vibration;

As shown in FIG.

That is, the welding apparatus according to the present invention is constituted by a horn including a horn tip capable of forming the above-described fine holes in the electrode terminal, so that compared with a conventional welding apparatus structure for performing welding on a flat bus bar, It is possible to provide an excellent adhesion between the bus bar (precisely the embossed structure portion) and the electrode terminal, and to provide stable welding quality.

In one preferred embodiment, the battery module assembly according to the present invention may be two or more battery modules in which cell units composed of two or more battery cells are connected in series and / or in parallel.

In the above structure, the electrode terminals of the cell unit are electrically connected to each other by the bus bar assembly, thereby providing the desired output and capacity.

In the above structure, the bus bar assembly is, for example,

(a) a cover plate made of an electrically insulating material and mounted on upper surfaces of the battery modules; And

(b) two or more bus bars mounted in a 'c' shape on the cover plate;

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One side of the electrode terminal may be welded to the side of the bus bar.

On the other hand, as the material of the electrode terminal, for example, aluminum or nickel can be used, but it is not limited thereto.

In one preferred example, the depth of the fine holes may preferably be 0.2 mm to 0.5 mm, and the spacing between the fine holes may be 0.8 mm to 1 mm. If the depth is too deep or the interval between the fine holes is too narrow, the property may be deteriorated or fusion may not be easy in the process of forming the emboss structure. On the other hand, when the depth is too shallow or the interval is too wide, It is difficult to perform the role and it may be difficult to exert a desired effect.

On the other hand, the shape of the horn tip is not particularly limited, but may be formed in a pyramidal shape on a vertical cross-section so as to easily form an embossed structure.

In another preferred embodiment, the welding of the bus bars to the electrode terminals can be done preferably by ultrasonic welding, so that deformation of the welds is minimized and can be easily used for thin electrode terminals.

The present invention also provides a battery module assembly manufactured using the welding apparatus.

Such a battery module assembly can provide a higher weldability between the electrode terminal and the bus bar than the conventional battery module assembly, thereby providing a battery module assembly with improved safety.

The present invention also provides a device comprising the battery module assembly. Preferred examples of such devices include, but are not limited to, electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, or electric power storage devices.

Since the structure and manufacturing method of the device are well known in the art, a detailed description thereof will be omitted herein.

As described above, the welding apparatus according to the present invention can improve the weldability between the electrode terminal and the bus bar by forming an emboss structure on the bus bar, thereby improving the safety of the battery module assembly.

1 is a perspective view of a typical representative pouch type battery;
2 is a partial perspective view of a battery module assembly according to one embodiment of the present invention;
3 is a perspective view of the cell unit of FIG. 2;
Figure 4 is a perspective view of the bus bar of Figure 2;
Figure 5 is a side view of the bus bar of Figure 2;
6 is a photograph of a welding apparatus according to another embodiment of the present invention;
Figure 7 is a partial view of Figure 6;
8 is a picture of a bus bar in an embodiment of the present invention;
9 is a photograph of a bus bar of a comparative example of the present invention;
Figure 10 is a picture of a bus bar after the shear force test of Figure 8;
11 is a photograph of a bus bar after the shear force test in Fig.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings, but the present invention is not limited by the scope of the present invention.

2 is a partial perspective view of a battery module assembly according to an embodiment of the present invention, and FIG. 3 is a perspective view of the cell unit of FIG.

Referring to these figures, the battery module assembly 200 includes six battery modules 210 in which the cell units 100 composed of two battery cells 10 are connected in parallel, and the cell unit 100 Are electrically connected to each other by the bus bar assembly 220. The bus bar assembly 220 is electrically connected to the electrode terminals 101,

The bus bar assembly 220 includes a cover plate 221 made of an electrically insulating material and mounted on the upper surface of the battery modules 210, ten buses And one side of the electrode terminal 101 is welded to the side surface of the bus bar 222. [

Fig. 4 is a perspective view of the bus bar of Fig. 2, Fig. 5 is a side view of the bus bar of Fig. 2, and Fig. 6 is a photograph of a welding apparatus according to one embodiment of the present invention , And Fig. 7 is a partial view of Fig.

2 and 3, a welding device 300 for ultrasonic welding the electrode terminal 11 and the bus bar 222 of the battery module assembly 100 is directly connected to the bus bar 222 The bus bar 222 is welded to the electrode terminal 11 by applying vibration to the bus bar 222 and the bus bar 222 is welded to the bus bar 222 so that the embossed fine holes 223 can be formed in the bus bar 222. [ A horn 310 comprising horn tips 311 corresponding to the fine holes 223; An anvil 320 for fixing the lower end of the bus bar 222 and transmitting the generated vibration to the bus bar 222; And a booster 330 for controlling the increase and decrease of vibration.

At this time, the depth W of the fine holes 223 is approximately 0.4 mm, the distance L between the fine holes 223 is approximately 0.9 mm, and the horn tips 311 are formed in a pyramid shape on the vertical cross section have.

Here, the ultrasonic welding is performed by applying ultrasonic waves to the fine holes 223 by the horn tips 311.

Hereinafter, the present invention will be described in detail by way of examples, but the scope of the present invention is not limited thereto.

Example 1

A pouch-type secondary battery having a structure in which an electrode assembly composed of a positive electrode / separator / negative electrode was built in a pouch-shaped battery case, and an electrode terminal having an aluminum material thickness of 0.4 mm was sealed so as to lead out of the battery case was manufactured . Then, a vibration of 3.1 Hz was applied to a bus bar made of copper having a thickness of 0.8 mm using a horn including a pyramidal horn tip, and the lower end of the bus bar was fixed by an anvil, As a result, a bus bar having a fine hole with a depth of 0.4 mm and a fine hole spacing of 0.9 mm was produced as shown in Fig.

Comparative Example 1

9 was manufactured in the same manner as in Example 1 except that the electrode terminal and the bus bar were jointed by ultrasonic welding using a horn not including a horn tip instead of pressing using a horn including a horn tip Respectively.

 [Experimental Example 1]

Shear force tests were performed on the structures manufactured in Example 1 and Comparative Example 1 five times, respectively. The results are shown in Figs. 10 and 11 and Table 1 and Table 2, respectively.

[Table 1]

[Table 2]

상기 표 1, 표 2와 도 10, 도 11의 사진에서 보는 바와 같이, 본 발명의 실시예 1의 버스 바들은 최대 하중 평균이 비교예 1에 비해 우수하여 높은 접착력을 제공하며, 표준편차가 작아 용접 신뢰성이 높음을 확인할 수 있다. 즉, 혼 팁들을 포함하는 혼을 이용하여 버스 바에 엠보 구조를 형성하여 용접시키는 것이, 엠보 구조를 형성하지 않은 구조에 비해 우수하고 안정된 용접 품질을 제공함을 알 수 있다.

As shown in Tables 1 and 2 and FIGS. 10 and 11, the bus bars of Example 1 of the present invention had a higher maximum load average than Comparative Example 1, Welding reliability is high. That is, it can be seen that forming and welding the emboss structure on the bus bar using the horn including the horn tips provides superior and stable welding quality compared to the structure without the emboss structure.

Those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.

Claims (12)

An apparatus for welding an electrode terminal and a bus bar of a battery module assembly,
A bus bar is fused to the electrode terminal by applying a direct vibration to the bus bar and the bus bar is welded to the bus bar in order to form embossed fine holes in the bus bar, (horn);
An anvil for fixing the lower end of the bus bar to transmit the generated vibration to the bus bar; And
A booster for adjusting the increase / decrease of the vibration;
Welding device comprising a. The welding device according to claim 1, wherein the battery module assembly is at least two battery modules in which cell units composed of two or more battery cells are connected in series and / or in parallel. The welding apparatus according to claim 2, wherein the electrode terminals of the cell unit are electrically connected to each other by a bus bar assembly. The method of claim 3, wherein the bus bar assembly,
(a) a cover plate made of an electrically insulating material and mounted on upper surfaces of the battery modules; And
(b) two or more bus bars mounted in a 'c' shape on the cover plate;
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Welding device, characterized in that one surface of the electrode terminal is welded to one side or both sides of the bus bar. The welding apparatus according to claim 1, wherein the electrode terminal is made of aluminum or nickel. The welding apparatus according to claim 1, wherein the depth of the fine holes is 0.2 mm to 0.5 mm. The welding apparatus according to claim 1, wherein the interval between the fine holes is 0.8 mm to 1 mm. The welding apparatus according to claim 1, wherein the horn tip is pyramidal in vertical section. The welding apparatus according to claim 1, wherein welding of the bus bars to the electrode terminals is performed by ultrasonic welding. A battery module assembly, characterized in that produced using the welding device according to any one of claims 1 to 9. A device comprising a battery module assembly according to claim 10. 12. The device of claim 11, wherein the device is an electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, or a power storage device.

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