A Fast Energy-efficient Pulse Preheating Strategy For Li-ion Battery At Subzero Temperatures

Electric vehicles suffer from significant driving range loss at subzero temperature environments due to reduced energy and power capability of Li-ion batteries. Therefore the battery must be heated to suitable operating temperature before the operation process begins. The effect of the pulse heating method based on the fuzzy logic control is investigated experimentally in this paper. Firstly, the pulse frequencies, amplitudes on cell temperature evolution are studied. Then the fuzzy logic control strategy is designed to obtain the variable pulse amplitude criterion based on the real-time internal resistance and temperature of the battery. The experiments are carried out under different battery initial values of state of charge with the same pulse frequency. Compared with the constant amplitude pulse preheating strategy, the proposed strategy can shorten the heating time by 2 to 4 minutes, and save the energy loss by 50 percent.