Module

Abstract

A flat secondary battery having a fusion-bonded sealing type laminate film as an armored body tends to be inferior in sealing reliability to a flat secondary battery having a welded sealing type can as an armored body, due to a difference in sealing method between the two batteries. Therefore, there has been a large challenge of finding the way to make the sealing reliability of the laminate film secondary battery closer to that of the can type secondary battery. The sealing reliability is improved by further increasing a sealing force without taking any measure to the existing laminate film secondary battery, in such a manner that the fusion bonding area of the existing laminate film secondary battery is sandwiched from upside and downside to be cramped from outside so as to mechanically add a sealing force from outside to the sealing force of the laminate film itself.

Description

CROSS-REFERENCE TO RELATED APPLICATION [0001] The present application is a continuation of International Application No. PCT / JP03 / 06934, which was filed on Jun. 2, 2003, which is herein incorporated by reference.TECHNICAL FIELD [0002] The present invention relates to a module constructed using a flat laminate film secondary battery, and more particularly to a structure for cramping the flat laminate film secondary battery. BACKGROUND ART [0003] Generally, a metal can type secondary battery is the most dominant type of secondary battery, and in many cases, this battery is produced in such a manner that, after inclusion of a power generating element and an electrolyte in a metal can, a step of extracting electrodes is performed and lastly, a metal cover is laser welded. Thus, the can type secondary battery has a high sealing property, being advantageous in having a very few problems in terms of leakage of an electrolyte from a metal can to outside, even in a long-term use. Meanwhile, ...

AI Technical Summary

Benefits of technology

[0007] On the other hand, when a sealing property of a can type battery is compared with that of a laminate type battery, it is obvious due to the difference in sealing method that the welded sealing method of the can type battery is more preferred. For making the sealing property of the laminate film as close to that of the can type battery as possible, it is necessary to improve the fusion bonding performance of the laminate film and also to widen the fusion bonding width thereof.

[0009] A module structure proposed in the present invention is that a four-side sealing section of an existing flat laminate film secondary battery having a laminate film as an armored body is mechanically cramped from upside and downside by module covers via sealing accessory plates. With the interposition of the sealing accessory plates, the sealing force of the laminate film itself is added with a sealing force to cramp the sealing section by the covers and the sealing accessory plates, making it possible to further improve the sealing property of the laminate film itself.

[0014] As opposed to this, the present invention provides a structure that can solve a problem having been unsolvable with the conventional module structures. A fundamental action of the present invention is described using FIG. 3. As illustrated in FIG. 3, the module structure of the present invention is that a laminate film sealing area 11 of the flat laminate film secondary battery 3 is cramped so as to be sandwiched from upside and downside by the top and bottom covers 1 and 2 of the module via the sealing accessory plates 4, and hence the laminate film sealing area 11 is mechanically cramped by the sealing accessory plates 4. Thereby, the sealing force of the laminate film itself is added with a sealing force of the sealing accessory plates 4 from outside by the sandwiching force, to improve the sealing property of the laminate film. The sealing area 11 is represented with a filled-in area in FIG. 4 illustrating a perspective view of a flat laminate film secondary battery, and this is a section sealed by fusion bonding.

Problems solved by technology

However, the improvement in fusion bonding performance of the laminate film requires development cost as well as a certain length of time, and the extension of the fusion bonding width requires development cost for a dedicated sealing device as well as a certain length of time.

There is further a problem that an increase in material cost causes an increase in product cost.

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