LITHIUM ION POLYMER SECONDARY BATTERY

摘要

PROBLEM TO BE SOLVED: To reliably prevent internal short-circuiting without reducing a discharge capacity. SOLUTION: In this lithium ion polymer secondary battery, a polymer electrolyte layer 17 is interposed between the active material 13 of a positive electrode sheet 11 structured by forming the active material 13 on the surface of positive electrode collector foil 12 and the active material 16 of a negative electrode sheet 14 structured by forming the active material 16 on the surface of negative electrode collector foil 15, and the positive electrode sheet 11 and the negative electrode sheet 14 are laminated with the one side rim 12a of the positive electrode collector foil 12 protruding from the one side rim 15a of the negative electrode collector foil 15 and with the other side rim 15b of the negative electrode collector foil 15 protruding from the other side rim 12b of the positive electrode collector foil 12. An filmy insulating members 18 are provided at both side rims of the polymer electrolyte layer respectively across the total length of the side rim so as to protrude from the both side rims. t2/t1 is 0.1-0.7, and s2/s1 is 0.02-0.8.