| 摘要 |
PROBLEM TO BE SOLVED: To lessen the suppression of volume change in a positive electrode and a negative electrode through a finely porous membrane by using a finely porous membrane, having a porosity with a specified value or higher and filling the pores with a polymer electrolytic substance within a specified range. SOLUTION: To fill pores of a finely porous membrane with a polymer electrolytic substance, a finely porous membrane having 80% or more porosity is used as the finely porous membrane and pores are filled with the polymer electrolytic substance with 20-80% or higher vacancy ratio by volume. Consequently, the finely porous membrane is sufficiently filled with the polymer electrolytic substance and the polymer electrolytic substance is brought into sufficient contact with a positive electrode or a negative electrode, and lithium ion is transferred smoothly. On the other hand, since spaces which are not filled with the polymer electrolytic substance exist in the pores of the finely porous membrane, even when the volume of the positive electrode and the negative electrode changes due to charging and discharging, the volume change suppressed less frequently by the finely porous membrane and moreover a sufficiently high charging and discharging capacity is obtained, and cycle property is improved also. |
