| 摘要 |
PROBLEM TO BE SOLVED: To restrain the deterioration of capacity without causing deterioration, even if a battery is used in an on-vehicle environment by using a binder formed of a copolymer of PVDF and HFP wherein the ratio of PVDF to HFP is in a specific range. SOLUTION: A binder in which the ratio of PVDF to HFP is 80-95:20-5 is used. When the ratio of initial capacity to the capacity after heating is evaluated as a capacity recovery rate, the capacity recovery rate is improved as compared with PVDF alone, when the mixing ratio of PVDF to HFP is in the range of 80-95:20-5. The initial peeling strength of an electrode agent according to a tape peel test is improved as compared with PVDF alone as well. Because gaps between particles inside a positive electrode agent and a negative electrode agent can be prevented from growing by improving the adhesion of the binder so that the internal resistance of a battery can be restrained from rising, the deterioration of capacity can be reduced. When this copolymer is used, baking temperature can be lowered as compared with the case that PVDF is used alone, and baking cost can be reduced. |
