A battery housing is configured to encase multiple battery cells comprises a supercapacitor shell. The supercapacitor shell comprises two layers each of carbon fiber reinforced with plastic; an electrode between the two layers, the electrode comprising negative electrode material, positive electrode material, and an electrolyte; a positive electrode terminal connected to the carbon fiber of one of the two layers; and a negative electrode terminal connected to the carbon fiber of another of the two layers. Edges of the two layers are laminated together to contain the electrode with the positive electrode terminal and the negative electrode terminal extending external to the laminated edges.