Separator for mat-immobilized-electrolyte battery

摘要

An electrolyte-immobilizing mat (38) for a mat-immobilized-electrolyte battery comprising a plurality of randomly-oriented resilient fibres resistant to and wettable by sulphuric acid electrolyte, wherein the mat (38) is held in a stressed, pre-compressed state by a resin which is substantially insoluble in sulphuric acid but is sufficiently degradable therein under battery formation conditions to free the mat (38) from its stressed state during formation and allow it to swell within a battery cell element (32). Thermo-setting resins, and particularly melamine-formaldehyde resin, are preferred. The invention is particularly useful with mats made from glass fibres.