Method for manufacturing gel polymer electrolyte secondary battery and gel polymer electrolyte secondary battery manufactured thereby

Abstract

A secondary battery has a structure including an internal core portion containing an electrolyte having a relatively lower crosslinking degree, and surrounded with a peripheral portion containing an electrolyte having a relatively higher crosslinking degree. It is possible to provide an effect of improving both ion conductivity and mechanical properties by virtue of such structural characteristics. The electrolyte portion having a lower crosslinking degree is confined by the electrolyte having a higher crosslinking degree to provide an effect of preventing electrolyte leakage. The secondary battery can be obtained by a simple method that includes crosslinking only the peripheral portion before the core portion reaches to a crosslinking temperature and is crosslinked under an environment preheated to the crosslinking temperature or higher. As a result, there is no adverse effect upon the processing efficiency, since any separate device or system line is not required to carry out the crosslinking.