New self-heating batteries will make electric cars independent of climatic conditions

Lithium-ion batteries are known to hate cold. At temperatures below 10 degrees Celsius, the batteries cannot be charged with the rated current, which is a big problem for electric cars operated in cold areas. The batteries of cars destined for the Scandinavian region, for example, are even equipped with small heating elements, and, despite such tricks, more powerful charging stations are installed in warm regions, providing faster battery charging than in cold regions.

A group of researchers from the University of Pennsylvania, led by Chao-Yang Wang, has developed a new type of rechargeable battery that is able to spend part of the energy on its own heating and to keep the temperature of the battery above critical. This, in turn, allows charging such a battery in 15 minutes, even if the ambient temperature drops to -43 degrees Celsius.

Unlike traditional batteries with two electrodes, the self-heating battery has a third electrode made of thin nickel foil. The temperature sensor, when the battery temperature drops below 25 degrees, closes the circuit that ensures the movement of electric current through the nickel electrode. Due to the electrical resistance of this electrode, it heats up and heats up the contents of the battery. After heating the battery to normal temperature, the impromptu heater turns off, and the energy begins to be spent already on charging the battery itself.

During the tests, prototypes of self-heating batteries were able to withstand 4,500 15-minute charge cycles at an ambient temperature of 0 degrees Celsius. At the end of a cycle of such rigorous tests, the loss of the battery’s electrical capacity did not exceed 20 percent, while a conventional battery under such conditions would have lost 20 percent of its capacity after 50 charge cycles.

In addition to being able to quickly charge in cold conditions, battery heating technology can make batteries safer to use. Indeed, at temperatures below 10 degrees during charging, lithium filaments and spikes begin to form in the electrolyte, which lead to a short circuit, spontaneous heating and fire of the batter

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