| 摘要 |
PROBLEM TO BE SOLVED: To provide a flat nonaqueous secondary battery with high safety through restraint of battery swelling by structuring an electrode group with straight parts parallel with a major axis and corner parts formed in a half-elliptical shape, in one made by sealing in a battery case together with nonaqueous electrolytic solution an electrode group winding a positive electrode plate and a negative electrode plate equipped with an active material around a porous insulator and molding it in a flat form by pressurization. SOLUTION: In the flat nonaqueous secondary battery 25 made by sealing in a battery case together with nonaqueous electrolytic solution an electrode group 1 winding the positive electrode plate 3 and the negative electrode plate 2 equipped with an active material around a porous insulator 4 and molding it in a flat form by pressurization, the electrode group 1 is structured of straight parts 6 parallel with a major axis 5, and corner parts 7 equipped with a vertex 12 of each wound-around layer on the major axis 5, with a contour line connecting a terminal end of the straight parts 6 and the vertexes 12 are formed in a curve made into an elliptical shape. COPYRIGHT: (C)2011,JPO&INPIT
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