| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a lithium ion secondary battery of high performance in which internal short-circuit due to overheating can be prevented efficiently while preventing deterioration of battery characteristics. <P>SOLUTION: In the lithium ion secondary battery equipped with a positive electrode which has a strip-like positive electrode current collector and a positive electrode mixture layer carried on the positive electrode current collector and which has a positive electrode current collector exposed part along at least one lengthy side of the positive electrode current collector, a negative electrode which has a strip-like negative electrode current collector and a negative electrode mixture layer carried on the negative electrode current collector and which has a negative electrode current collector exposed part along at least one lengthy side of the negative electrode current collector, and a separator interposed between the positive electrode and the negative electrode, the width in the short direction of the negative electrode mixture layer is set larger than that in the short direction of the positive electrode mixture layer, and porous heat resistant layers are arranged at a region along the border part with the negative electrode current collector exposed part out of the surface of the negative electrode mixture layer and at a region of the surface of the negative electrode mixture layer opposing to the border part between the positive electrode mixture layer and the positive electrode current collector exposed part via the separator. <P>COPYRIGHT: (C)2011,JPO&INPIT |
