| 摘要 |
PROBLEM TO BE SOLVED: To provide a thin nonaqueous secondary battery having excellent charge and discharge characteristics and shelf characteristics at a high temperature, and discharge characteristics at a low temperature, and intending to enhance safety by preventing an electrode mixture layer form dropping off and an electrode plate from being cut off. SOLUTION: In this nonaqueous electrolyte secondary battery equipped with a positive electrode and a negative electrode formed by containing an active material capable of occluding and discharging a lithium ion and a binder, a separator, and a nonaqueous electrolyte, a high capacity, excellent charge and discharge cycle characteristics at a high temperature and excellent discharge characteristics at a low temperature can be imparted to the battery by using a fluorine based high copolymer having a weight average molecular weight of not less than 300,000 and not more than 600,000 as a binder for the positive electrode and/or the negative electrode. A copolymer of vinylidene fluoride and hexa-fluoropolypropylene is preferable for this fluorine based high copolymer, and the electrode mixture layer can be prevented from dropping off and the electrode plate is prevented from being cut off, by setting the vacancy percentage of the electrode mixture layer at not less than 17% and not more than 30%. |
