A new charging mode of Li-ion batteries with LiFePO4/C composites under low temperature

Li-ion batteries with LiFePO4/C composites are difficult to be charged at low temperatures. In order to improve the low temperature performance of LiFePO4/C power batteries, the charge-discharge characteristics were studied at different temperatures, and a new charging mode under low temperature was proposed. In the new charging mode, the batteries were excited by current pulses with the charge rates between 0.75 C and 2 C, while the discharge rates between 3 and 4 C before the conventional charging (CC-CV). Results showed that the surface temperature of Li-ion battery ascended to 3 A degrees C at the end of pulse cycling when the environment temperature was -10 A degrees C. Comparing with the conventional charging, the whole charge time was cut by 36 min (23.4%) and the capacity was 7.1% more at the same discharge rate, respectively.