Lower-temperature molten-salt electrolyte battery for EVs and hybrids from Sumitomo

Sumitomo earlier reported that it has achieved energy densities as high as 290 Wh/L with the new battery. A drawback to the general class of molten salt batteries (e.g., the ZEBRA battery, or GE’s Durathon sodium-metal halide batteries, earlier post) has been the need for high operating temperatures to keep the salt molten. Being non-volatile and non-flammable, and with high ion concentrations, molten salt makes an excellent battery electrolyte and can offer high energy and power densities. In a joint project with Kyoto University, Sumitomo developed a molten salt with a melting point as low as 57 °C. Using this salt, it developed the new molten-salt electrolyte battery. Since it comprises only nonflammable materials, the new battery will not ignite on contact with air from outside, nor is there thermal runaway from overcharging or temperature rises in the battery. For this reason, Sumitomo says, there is no need for waste-heat storage or fire- and explosion-proof equipment, so the batteries can be packed close together. The company earlier reported that based on its trial calculations, assuming equal capacity, the new battery had half the volume of lithium-ion batteries and one quarter that of sodium-sulfur batteries, enabling miniaturization. Sumitomo is continuing work on the battery to find molten salt that can be used at still lower temperatures. Resources * Sumitomo Electric Annual Report 2011 first appeared