Method of making multi-layer electrochemical cell devices

Abstract

A method of making a laminated multi-layer electrochemical cell device structure comprising positive and negative electrode layer members of polymeric matrix composition having a microporous polyolefin membrane separator member interposed therebetween wherein the separator membrane includes a polymer coating layer. The separator is treated to provide a deposited coating of a primary plasticizer for the polymer coating layer. The device electrode and separator members are then assembled and laminated at a compressive force and temperature at which the plasticizer film softens the polymer coating of the separator member sufficiently to establish a strong interfacial bond with the matrix polymers of the electrode members and thereby form a laminated unitary cell structure. In another embodiment, the primary plasticizer comprises a component of the electrode polymeric matrix compositions. In either embodiment, the plasticizer subsequently volatilizes from the structure to further strengthen the interfacial bond, yet its temporary presence in the interfacial region of the multi-layer cell structure enables lamination of the cell members at a temperature below the pore-collapse temperature of the separator membrane, thereby preserving the thermal shut-down protection feature of the microporous separator.