Systems, structures and materials for electrochemical device thermal management

This disclosure provides a casing for the thermal management and protection of an electrochemical cell. The casing may comprise an inner surface configured to be in physical contact with at least a portion of an outer surface of an electrochemical cell. The inner surface may be substantially solid at room temperature. The casing may also comprise a polymer matrix which itself comprises two or more temperature management materials. At least one of the two or more temperature management materials may comprise a microencapsulated phase change material having a latent heat of at least 5 Joules per gram and a transition temperature between 0° C. and 100° C., and at least one other of the two or more temperature management materials may comprise an elastomeric material. The polymer matrix may be substantially homogeneous.