Power supply systems and associated methods of operation are provided based on the incorporation of a supply of phase change material in thermal contact with at least one cell element capable of a heat-generating charge or discharge of power. Also disclosed, such as for increased or improved heat transfer and dissipation, is battery module incorporation of a heat-conductive containment lattice member such as having a plurality of openings wherein at least a portion of the supply of the phase change material can be disposed as well as the inclusion of a plurality of module housing-protruding heat transfer fins.