| 摘要 |
PROBLEM TO BE SOLVED: To prevent direct short-circuiting of a positive electrode and the negative electrode, and to avoid the spread of the internal short circuit, by forming a porous heat resisting layer on the active material of the positive electrode and/or the negative electrode, in a nonaqueous electrolyte secondary battery. SOLUTION: In a nonaqueous electrolyte secondary battery, porous heat resisting insulation layers 20 are formed on both surface of the negative electrode active material of a negative electrode collector 7, and it is cut to make into a negative electrode. And a positive electrode having positive electrode active material layers 4 on both surfaces of a positive electrode collector 5 is also obtained. The negative electrode and the positive electrode are laminated through a separator 8, and the laminated body is wound numerous turnes in a spiral form, and an insulating sheet is wound on the outermost periphery so as to form an electrode spiral body. The porous heat resisting insulation layer 20 was provided on the negative electrode active layer 6, but it may be provided on the positive electrode active material layer 4, or on both layers 4 and 6. Consequently, even though an external heating, or a heating by an external shock is generated, the insulation can be maintained between the positive electrode and the negative electrode, and as a result, an advantage of not short- circuiting the electrodes at a large area can be obtained. |
