lithium-ion battery extremes

Taking lithium-ion batteries to new extremes

"Under experimental conditions ranging from –20° C ( –4° F; very cold) to 45° C (114° F; very hot), the thermal regulator performed well, warming quickly from –20° C ( –4° F) to around 20° C (68° F) due to heat from the battery retained by the air gap and increasing the uable factor of the battery by a factor of three. At the opposite extreme, the thermal regulator also performed admirably, transitioning to the ON state at around 45° C (113° F) whereafter the temperature rise in the LIBs was limited to 5° C (9° F). After testing this thermal regulator set-up through 1,000 ON/OFF cycles, the investigators found the OFF state performance to be just slightly degraded (an 8.5% battery capacity reduction at –20 ° C [–4° F]) whereas the ON state performance remained unchanged."