JP2008021507A - Battery pack - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a battery pack that cannot be easily decomposed. <P>SOLUTION: An insulating film 2 covers at least front and rear surfaces of a battery cell 3 in a battery unit, consisting of a protective circuit board 5 in which a battery cell 3 is connected to a battery cell 3. The end in winding direction of the insulating film 2 is positioned on the side surface of the battery cell 3, and a resin case 1 provided with an opening to expose the front and rear surfaces of the battery cell 3, covers both the side surfaces and both the end surfaces of the battery unit. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a battery pack, and more particularly, to a structure of a case that covers a battery unit such as a lithium secondary battery and a protection circuit board used in the battery pack.

  In recent years, with the progress of miniaturization and weight reduction of portable electronic devices such as cellular phones, batteries such as lithium ion secondary batteries as power sources for driving them have been demanded from the market. Therefore, there is an urgent need for higher capacity.

  In addition, a battery pack that can be attached to and detached from the main body is used as a power source for a portable electronic device such as a cellular phone. In this battery pack, a battery unit including a battery cell such as a lithium secondary battery, a protection circuit board, and the like is housed in a case or the like and is packaged. There are two types of battery packs, such as those covered with a case made of metal, synthetic resin, etc., and those covered with an insulating film such as a label film or a heat-shrinkable film.

  FIG. 3 is a view showing an example of a conventional battery pack, FIG. 3 (a) is a perspective view of a state in which a label film is set on a battery cell, and FIG. 3 (b) is an exterior view of the battery cell with a label film. FIG. In a conventional battery pack, as a simple exterior, as shown in FIG. 3, an insulating plate 6 is attached around the terminal portion 4 at the upper end of the battery cell 3, and the insulating film 2 such as a label film is provided on the front and back surfaces and the side portions. It was covered and covered. For example, in patent document 1, it was the structure which covered the battery cell with the heat contraction tube.

  FIG. 4 is a view showing another example of a conventional battery pack, FIG. 4 (a) is a perspective view, FIG. 4 (b) is a transverse sectional view, and FIG. 4 (c) is a longitudinal sectional view. It is. Many conventional battery packs have the following structure. That is, the upper and lower cases are sandwiched between the upper case and the lower case so as to accommodate the battery cell 3 and the protection circuit board 5, and the front and back surfaces of the battery cell 3 and the resin case 1 are fixed to each other by ultrasonic welding. The structure is covered with 2 and covered. Here, since the resin case 1 is not provided on the front and back surfaces of the battery cell 3 and the thickness of the resin case 1 is equal to that of the battery cell 3, the battery pack is accommodated in the thickness of the battery pack. It is determined by the thickness of the cell 3 and the thickness of the insulating film 2. Here, the insulating film 2 is a film having a thickness of about 30 to 100 μm made of, for example, polyvinyl chloride, polyethylene terephthalate, polyethylene, polyimide, polyetherimide, polyester, or ethylene-vinyl acetate copolymer. . Patent Document 2 describes an example of such a battery pack.

Japanese Patent Laid-Open No. 2005-19242 JP 2005-1000068 A

  However, in the conventional battery pack, the adhesive strength of the insulating film is limited, and it can be easily disassembled because it is relatively easy to remove the insulating film or the like. In Patent Document 2, there is a description of using a tamper-proof label. However, if the protective circuit board, battery cell, etc. accommodated inside can be easily touched by disassembly, a safety point of view accompanying misuse by the user There was a problem.

  An object of the present invention is to provide a battery pack that is not easily disassembled by a sharp blade.

  The battery pack of the present invention covers at least the front and back surfaces and the side surfaces of the battery cell with an insulating film among battery units composed of a battery cell and a protective circuit board connected to the battery cell, and an end portion in the winding direction of the insulating film is The resin case is located on the side surface of the battery cell and has an opening so as to expose the front and back surfaces of the battery cell to the outside, and covers both side surfaces and both end surfaces of the battery unit. . In the battery pack of the present invention, the resin case may be molded, or the resin case may be made of a low temperature molding resin and molded on a battery unit. And the said insulating film may cover the terminal part periphery of a battery cell further.

  According to the present invention, when covering the battery cell with the insulating film, the end of the insulating film is structured to be the side surface of the battery cell, and the end of the insulating film in the winding direction is sandwiched between the resin cases. It becomes a battery pack. In addition, the insulating film serves as a battery pack that also serves as an insulating plate of the battery cell.

  According to the battery pack of the present invention, it is possible to realize a battery pack having a structure that cannot be easily disassembled and having insulation properties and having a small number of parts and manufacturing processes.

  Next, embodiments of the present invention will be described with reference to the drawings.

  1 is a diagram showing a battery pack according to Embodiment 1 of the present invention, FIG. 1 (a) is a perspective view, FIG. 1 (b) is a transverse sectional view, and FIG. 1 (c) is a longitudinal sectional view. FIG.

  The production of the battery pack will be described. First, after the insulating plate 6 is bonded to the terminal portion at the upper end of the battery cell 3 in which the battery element is housed in a metal can made of aluminum or the like, the protective circuit board 5 is set, and the battery cell 3 is electrically connected to the battery cell 3. Form a unit. Next, the front and back surfaces of the battery cell 3 and both side surfaces are covered with a polyester insulating film 2 having an adhesive on one side. At this time, the winding end portion of the insulating film 2 is arranged not to be the front and back surfaces but to the side surface portion. By arrange | positioning in a side part, the influence on the thickness of the battery pack of the overlap part in the winding end part of the insulating film 2 can be avoided. For the insulating film, polyester, polyvinyl chloride, polyethylene terephthalate, polyethylene, polyimide, polyetherimide, ethylene-vinyl acetate copolymer, and the like may be used.

  Next, the periphery of the battery unit composed of the battery cell 3 and the protection circuit board 5 is covered with a resin case 1. At this time, the thickness of the battery pack can be reduced by providing openings in portions corresponding to the front and back surfaces of the battery cell 3 of the resin case 1. The resin case 1 can be formed by being sandwiched between an upper case and a lower case having openings so as to accommodate the battery cells 3 and the protection circuit board 5, and fixing the upper case and the lower case by ultrasonic welding. . Alternatively, the resin case 1 can be formed using a low-temperature molding resin such as a polyamide resin which is set at 190 to 240 ° C. by setting the battery unit in a molding die. In this case, there is an advantage that molding and assembling can be performed at the same time, and since there is no joint, it is difficult to disassemble. By adopting a structure in which the winding end portion of the insulating film 2 covering the battery cell 3 is sandwiched between the resin cases 1, it becomes difficult to peel off the insulating film and the battery pack cannot be easily disassembled, and the safety of the battery pack is improved. It can be secured. The molding resin may be polyolefin, polyester, urethane or the like.

  FIG. 2 is a diagram showing an intermediate step of the battery pack according to Embodiment 2 of the present invention, FIG. 2 (a) is a perspective view of a state in which an insulating film is set on the battery cell, and FIG. It is a perspective view after coat | covering a battery cell with an insulating film.

  In the battery pack according to Embodiment 2 of the present invention, the insulating film 2 is also provided with the function of an insulating plate that adheres to the terminal portion at the upper end of the battery cell 3. That is, the terminal part of the upper end part of the battery cell 3, the front and back surfaces of the battery cell 3, and both side surfaces are covered with the insulating film 2 made of polyester having an adhesive on one side. Thereafter, the protection circuit board 5 is set on the terminal portion at the upper end of the battery cell 3 and is electrically connected to the battery cell 3 to form a battery unit. Next, the resin case 1 covers the periphery of the battery unit including the battery cell 3 and the protection circuit board 5 as described above. Here, the resin case 1 can be provided similarly to the first embodiment of the present invention. In Embodiment 2 of the present invention, by incorporating the same shape as the insulating plate into the insulating film 2, parts can be shared, and member management, pasting processes, and the like can be reduced.

The figure which shows the battery pack of Embodiment 1 of this invention, Fig.1 (a) is a perspective view, FIG.1 (b) is a cross-sectional view, FIG.1 (c) is a longitudinal cross-sectional view. The figure which shows the middle process of the battery pack of Embodiment 2 of this invention, FIG. 2 (a) is a perspective view of the state which set the insulating film to the battery cell, FIG.2 (b) has coat | covered the battery cell with the insulating film. FIG. FIG. 3A is a perspective view of a conventional battery pack, FIG. 3A is a perspective view of a state in which a label film is set on a battery cell, and FIG. 3B is a perspective view after the battery cell is covered with a label film. FIG. 4A is a perspective view, FIG. 4B is a transverse sectional view, and FIG. 4C is a longitudinal sectional view showing another conventional battery pack.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Resin case 2 Insulation film 3 Battery cell 4 Terminal part 5 Protection circuit board 6 Insulation board

Claims (4)

  Covering at least the front and back surfaces and side surfaces of the battery cell with an insulating film among the battery units comprising the battery cell and the protection circuit board connected to the battery cell, and the end portion in the winding direction of the insulating film is located on the side surface of the battery cell And the battery pack which covered the both sides | surfaces and both end surfaces of the said battery unit with the resin-made case which provided the opening part so that the front and back of the said battery cell might be exposed outside.   The battery pack according to claim 1, wherein the resin case is molded.   The battery pack according to claim 1 or 2, wherein the resin case is made of a low-temperature molding resin and is molded on the battery unit.   The battery pack according to claim 1, wherein the insulating film further covers the periphery of the terminal portion of the battery cell.

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