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Flat nonaqueous secondary battery

A secondary battery, non-aqueous technology, applied in the field of flat non-aqueous secondary batteries, can solve the problems of exceeding the upper limit of thickness, increasing the thickness of the electrode group, and easy expansion of the electrode plate, so as to suppress the expansion and inhibit the increase of the thickness of the battery. Effect

Inactive Publication Date: 2012-06-20
PANASONIC CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] However, if the active material density of the electrode plate is increased, the electrode plate is likely to expand during charge and discharge, and as a result, the thickness of the electrode group increases beyond the specified upper limit of thickness.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment approach 1

[0042] figure 1 Shown therein is an electrode group 1 produced by winding a laminated electrode body 36 composed of a negative electrode plate 2, a positive electrode plate 3, and a porous insulator 4 three times or more. The electrode group 1 is composed of a long axis 5, a flat-plate-shaped straight side 6 parallel to the long axis 5, and a long axis 5 with vertices 12 of each winding layer, and a curve connecting the ends of the straight side 6 and the vertices 12 A pair of curved corners 7 constituted. In addition, the electrode group 1 is fixed by a terminal tape (fixing member, adhesive tape) 8 for preventing slack of the electrode plate. In addition, the expansion 10 of the straight side portion 6 and the expansion 9 of the corner portion 7 of the electrode plate during charge and discharge are indicated by arrows.

[0043] In addition, figure 2 (a) is a partial cross section of the corner portion 7 of the electrode group 1. The corner portion 7 is provided with the ver...

Embodiment approach 2

[0062] In the second embodiment, only the size of the gap of the wound laminated electrode body 36 is different from that in the first embodiment, and other configurations, materials, etc. are the same as those in the first embodiment, so only the differences from the first embodiment will be described.

[0063] In the corner portion 7 of the electrode group 1 of this embodiment, as figure 2 As shown in (b), the gap 13d existing on the innermost ring side is the largest, and the gaps 13e and 13f of the other winding layers are smaller than the gap 13d and have the same size.

[0064] The second embodiment also has the same effect as the first embodiment.

[0065] Hereinafter, in order to explain the present invention more specifically, examples are used for description.

Embodiment 1

[0067] In embodiment 1, at the corner 7 of the electrode group 1, such as figure 2 As shown in (a), the gap 13a on the inner ring side is large, and the gaps 13b and 13c on the outer ring side are sequentially reduced.

[0068] Then, make image 3 The battery shown has a flat non-aqueous secondary battery 25 with a thickness 28 of 6 mm, a width of 35 mm, and a height of 35 mm.

[0069] First, regarding the preparation of the electrode plate, 100 parts by weight of lithium cobalt oxide as the positive electrode active material and 2 parts by weight of acetylene black as the conductive material relative to 100 parts by weight of the active material were combined with a double-wrist mixer. The active material is 2 parts by weight of polyvinylidene fluoride as a binding material and an appropriate amount of N-methyl-2-pyrrolidone are stirred and kneaded together to prepare a positive electrode mixture paint.

[0070] Next, the positive electrode mixture paint was applied to both sides o...

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Abstract

The present invention relates to a flat nonaqueous secondary battery in which a laminated electrode body including positive and negative electrode plates equipped with active materials and a porous insulator between the positive and negative electrode plates is wound to form an electrode group having a flat-shaped cross-section and consisting of a plate-shaped straight portion and a pair of curved corner portions. The secondary battery is getting widely used as a power supply for portable electronic devices, but it is desired to further increase the capacity thereof as recent electronic devices are becoming more and more multifunctional. In order to increase the capacity, the electrode plates are pressed to a specified thickness by using, for example, a press, thereby increasing the densities of the active materials. However, there has been a problem that when the densities of the active materials are increased, the electrode plates tend to expand during charging and discharging, so that, as a result, the thickness of the electrode group increases and exceeds the upper limit of the specified thickness. The present invention solves the above problem in such a way that in at least two adjacent gaps of the laminated electrode body at the corner portions of the secondary battery, the gap on the inner circumferential side is made larger than the gap on the outer circumferential side.

Description

Technical field [0001] The present invention relates to a flat non-aqueous secondary battery using an electrode assembly for a flat non-aqueous secondary battery. Background technique [0002] In recent years, in lithium secondary batteries widely used as power sources for portable electronic devices, a carbonaceous material capable of inserting / deintercalating lithium is used in the negative plate, and LiCoO is used in the positive plate. 2 A composite oxide of transition metal and lithium is used as the active material. As a result, a secondary battery with a high potential and a high discharge capacity is realized. However, with the multi-functionalization of electronic equipment and communication equipment in recent years, a higher capacity is desired. In electronic equipment and communication equipment, most of the space for accommodating batteries is square (cube), so flat non-aqueous secondary batteries that house power generation elements in battery cases are often used. ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M10/0587H01M10/0566
CPCY02E60/12H01M10/0431H01M10/0587Y02E60/10Y02P70/50H01M10/0566
Inventor 石川俊树
Owner PANASONIC CORP