KR20130111055A - Battery pack employed with electrical connecting member of noble structure - Google Patents

Abstract

PURPOSE: A battery pack prevents damage to an internal electrode and a separator by transferring heat generated by welding to the side wall of a cylindrical battery cell. CONSTITUTION: A battery pack (100) is mounted to a pack case in a state where two or more cylindrical battery cells (110, 120) are electrically connected to each other by a connection member. The connection member is in contact with each electrode terminal of the cylindrical battery cells. A welding point to the connection member to the electrode terminal of the battery cell is formed on the electrode terminal part corresponding to the side wall of the cylindrical case of a battery cell. The connection member consists of a metal plate (200). The welding point is formed by laser welding.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a battery pack including a connection member having a novel structure,

The present invention relates to a battery pack including a connecting member having a novel structure, and more particularly to a battery pack having two or more cylindrical battery cells mounted on a pack case in a state of being electrically connected by a connecting member , The connecting member is positioned to be in contact with the electrode terminal of each cylindrical battery cell and the welding point of the connecting member to the battery cell electrode terminal is formed at the electrode terminal portion corresponding to the cylindrical case wall of the battery cell To a battery pack.

As technology development and demand for mobile devices increase, the demand for secondary batteries as energy sources is rapidly increasing.

The secondary battery may be used in the form of a single battery, or in the form of a battery pack in which a plurality of unit cells are electrically connected, depending on the type of external equipment in which the secondary battery is used. For example, a small device such as a mobile phone can operate for a predetermined period of time with the output and capacity of one battery, while a medium or large size such as a notebook computer, a portable DVD, a small PC, an electric vehicle, a hybrid electric vehicle, etc. Large devices require the use of battery packs with multiple batteries due to power and capacity issues.

Such a battery pack is manufactured by connecting a protection circuit or the like to a core pack in which a plurality of unit cells (secondary batteries) are arranged in series and / or in parallel. When a rectangular or pouch-shaped battery is used as the unit cell, the unit cells may be manufactured by stacking large-sized surfaces so as to face each other, and then connecting the electrode terminals by a connecting member such as a bus bar. Therefore, when a cubic battery pack having a hexahedral structure is manufactured, a prismatic or pouch type secondary battery is advantageous as a unit cell.

On the other hand, although the cylindrical secondary battery generally has a larger capacitance than the square type and pouch type secondary battery, the arrangement of the cylindrical secondary battery in the laminated structure is not easy. However, when the shape of the secondary battery pack as a whole is a linear or plate-like structure, the structure is more advantageous than the square or pouch type.

Accordingly, in the case of a notebook computer, a portable DVD, a small-sized PC, etc., a battery pack in which a plurality of cylindrical secondary batteries are connected in a serial manner or in parallel and in series is widely used. As a structure of the core pack used in such a battery pack, for example, a linear structure of 2P (parallel) -3S (serial), a plate structure of 2P-3S, a linear structure of 2P- A linear structure of 1P-3S, a plate-like structure of 1P-3S, and the like are used.

The parallel connection structure is achieved by arranging two or more cylindrical secondary cells adjacent to each other in the lateral direction thereof with the electrode terminals oriented in the same direction and welding them to the connecting member. These parallel type cylindrical secondary batteries are also referred to as "bank ".

The series connection structure may be such that two or more cylindrical secondary batteries are arranged in a continuous manner so that the electrode terminals of opposite polarities are continuous, or two or more cylindrical secondary batteries Are arranged adjacently in the lateral direction, and are welded to the connecting member.

For electrical connection of such cylindrical secondary batteries, spot welding is generally performed using a thin connecting member such as a metal plate or the like.

FIGS. 1 and 2 schematically show a process of connecting a plurality of cells using a metal plate.

1, the batteries 20 and 21 are first fixed to the jig 10, the metal plate 30 is positioned on the terminal of the battery 20, and then spot welding is performed with the welding tip 40. These cells 20 and 21 are connected in a parallel manner. Then, as in Fig. 2, the other pair of parallel cells 22 and 23 are spot welded. In order to connect the parallel battery pairs 20, 21, 22, and 23 in series, they must be positioned at 90 degrees and then the metal plate 30 must be bent by 90 degrees. This operation is performed by the other pair of parallel cells 24 , 25).

In order to form a battery pack having a high output and a large capacity, it is necessary to connect a plurality of battery cells in series or in parallel. In order to maintain the performance of the battery pack uniformly, a stable coupling method do. The electrical connection between these battery cells is generally accomplished through soldering or welding, preferably spot welding.

However, the spot welding or soldering process between the battery cells has the following problems.

Specifically, the spot welding or soldering process requires the skilled skill and know-how of the operator, and the maintenance of the parameters for determining the strength of the welding must be continuously performed. Therefore, the production process becomes complicated and the cost increases, It acts as a factor that hinders efficiency.

In addition, in a process of performing spot welding or soldering directly on the battery cell, a short-circuit (short-circuit) may occur in the welded part due to vibration or external impact of the battery pack, and electrical or thermal damage is applied between the battery cell and the connecting member , Which threatens the safety of the battery and increases the defect rate of the product. Furthermore, when a failure occurs in some battery cells (s) during the manufacturing process or use, all the battery cells constituting the battery pack have to be disposed.

Accordingly, there is a high need for a technique for securing the safety of a battery by solving the above-mentioned problems and fundamentally preventing a stable connection structure between the battery cells and electrode damage to an external force.

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.

The inventors of the present application have conducted intensive research and various experiments and have found that the welding point at which the electrode terminals of the cylindrical battery cells and the connecting member are in contact with each other by welding is located at a portion corresponding to the cylindrical case wall of the battery cell The heat generated by welding is transferred to the barrier ribs to prevent damage to the internal electrodes and the separator.

In order to achieve the above object, a battery pack according to the present invention is a battery pack in which two or more cylindrical battery cells are mounted on a pack case in a state of being electrically connected by a connecting member, And the welding point of the connecting member to the battery cell electrode terminal is formed in the electrode terminal portion corresponding to the cylindrical case wall of the battery cell.

Therefore, by forming the welding points at which the electrode terminals of the cylindrical battery cells and the connecting members are in contact with each other by welding, heat generated by the welding is applied to the partition walls And is radiated to the outside through the partition wall, so that damage to the internal electrode and the separation membrane can be prevented.

The connecting member is a conductive plate which is easy to be electrically connected to the battery cell, and can be preferably a metal plate. The metal plate is made of a pure metal such as nickel, copper, aluminum, Or the like, or the like.

In one preferred example, the connecting member may be a structure in which a plating layer is formed to prevent corrosion of the metal plate body.

In some cases, the plating layer may be formed on all or a part of one surface or both surfaces of the plate body. Preferably, the plating layer is formed on all sides of both surfaces of the plate body to maximize oxidation and corrosion prevention effects of the plate body. Do.

The welding point can be preferably performed by laser welding, and the laser welding is accomplished by a non-contact method.

Since the cylindrical battery cell is easy to ensure close contact with the connecting member due to the difference in flatness of the bottom surface, a separate additional mechanism for securing the close contact with the laser welding is not required. In addition, There is no need for an additional process for forming the slit. Laser welding is well known in the art of metals, and a detailed description thereof is omitted herein.

In the present invention, the fact that the welding point is formed at the electrode terminal portion corresponding to the cylindrical case partition wall of the battery cell means that the welding spot is formed at the electrode terminal portion near the cylindrical case partition wall.

In one preferred example, the welding point is a structure formed in the electrode terminal region in a range of 0 to 40% in size from the imaginary circle corresponding to the cylindrical case partition wall with respect to the radius of the imaginary circle have. If the welding point exceeds the above range, the welding strength may be lowered or the effect of the present invention may not be exhibited. A more preferable range may be a range of 5 to 30% in size based on the radius of the imaginary circle.

In the above structure, the welding points are preferably arc-shaped along the cylindrical case partition wall and formed in the electrode terminal portion in two or more numbers.

More preferably, the welding points may be formed in two or more numbers on both sides of the center of the imaginary circle corresponding to the cylindrical case partition wall. Needless to say, the number and shape of the welding points are not particularly limited.

The welding points at both ends may be spaced from each other due to the difference in flatness of the contact surfaces between the electrode terminals and the connecting member.

Therefore, it is easy to secure the contact between the electrode terminal and the connecting member, and the heat dissipating effect is excellent, and continuous welding of the large-capacity battery pack is possible.

The present invention provides a battery pack in which two or more cylindrical secondary batteries are mounted on a pack case in a state of being electrically connected by a connecting member.

Also, the battery pack according to the present invention can be used as a power source for a wireless device such as a portable DVD, a PMP, a PSP, a small PC, etc., which requires a large output capacity, and more preferably as a power source for a notebook computer.

Since such a battery pack and a device including the same are known in the art, detailed description thereof will be omitted herein.

As described above, in the battery pack according to the present invention, the welding points at which the electrode terminals and the connecting members of the cylindrical battery cells are in contact with each other by welding are formed at the portions corresponding to the cylindrical case walls of the battery cells, And is transmitted to the barrier ribs of the cylindrical battery cells, thereby preventing damage to the internal electrodes and the separation membrane.

Further, the battery pack according to the present invention preferably performs a non-contact welding method using a laser, so that it is possible to simplify the welding process and components since additional processing and equipment are not required.

FIGS. 1 and 2 are schematic diagrams of a process of connecting a plurality of cells using a metal plate according to the related art;
3 is a side view of a plurality of cells connected by a metal plate in accordance with one embodiment of the present invention;
4 is a bottom view of a cylindrical battery according to the present invention in which a metal plate is laser welded to an electrode terminal.

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.

FIG. 3 schematically shows a side view of a plurality of cells connected by a metal plate according to an embodiment of the present invention. FIG. 4 shows a state in which a metal plate is laser welded to an electrode terminal of a cylindrical battery according to the present invention Is schematically shown.

Referring to these figures, in a battery pack 100, electrode terminals (-) of a pair of cylindrical battery cells 110 and 120 are coupled by a metal plate 200 in a laser welding manner.

Welding points 115 and 125 are formed at portions where the pair of cylindrical battery cells 110 and 120 and the metal plate 200 are in contact with each other, Shaped partition walls 111 and 121, which are electrode terminals (-) of the electrodes 110 and 120, respectively.

The welding points 115 and 125 are formed at positions corresponding to the center of the virtual circle A along the case partition wall of the cylindrical battery cells 110 and 120 among the portions overlapping with the metal plate 200, (110, 120).

Specifically, the welding points 115 and 125 are positioned at an angle of 0 to 40% with respect to the radius r of the imaginary circle A in the inward direction from the imaginary circle A corresponding to the cylindrical case partition wall, Is formed in the distance range L corresponding to 5 to 30% size.

The welding points 115 and 125 are performed in a noncontact manner without any additional equipment such as a jig or a welding tip and are separated from each other due to the difference in flatness of the connection surfaces of the electrode terminal The spacers 112 and 122 are formed naturally.

The spacers 112 and 122 are formed in a predetermined space between the electrode terminal (-) and the metal plate 200, and the heat generated during the welding process is dispersed into the barrier ribs. Therefore, .

While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments.

Claims (12)

A battery pack in which two or more cylindrical battery cells are mounted on a pack case in an electrically connected state by a connecting member,
The connection member is positioned to contact the electrode terminal of each cylindrical battery cell, and the welding point of the connection member to the battery cell electrode terminal is formed in the electrode terminal portion corresponding to the cylindrical case partition wall of the battery cell Battery pack to say. The battery pack according to claim 1, wherein the connecting member is formed of a metal plate. The battery pack according to claim 1, wherein the connection member has a corrosion-resistant plating layer formed on the metal plate body. The battery pack as claimed in claim 1, wherein the welding spot is formed by laser welding. The battery pack as claimed in claim 4, wherein the laser welding is performed by a non-contact method. The method of claim 1, wherein the welding point is formed in the electrode terminal portion in the range of 0 to 40% of the size of the virtual circle in the inner direction from the virtual circle corresponding to the cylindrical case partition wall, based on the radius of the virtual circle. Battery pack to say. The method of claim 6, wherein the welding point is formed in the electrode terminal portion in the range of 5 to 30% in size from the imaginary circle corresponding to the cylindrical case partition wall, based on the radius of the imaginary circle. Battery pack to say. The battery pack as claimed in claim 1, wherein the welding point is formed at an electrode terminal portion in an arc shape along a cylindrical case partition wall. The battery pack as claimed in claim 8, wherein the welding point is formed in two or more numbers at both ends of the welding point with respect to the center of the virtual circle corresponding to the cylindrical case partition wall. The battery pack as claimed in claim 9, wherein the welding points at both ends are spaced apart from each other due to a difference in the flatness of the contact surface between the electrode terminal and the connecting member. A wireless device comprising the battery pack according to any one of claims 1 to 10. 12. The wireless device of claim 11, wherein the wireless device is a notebook computer.

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