A rapid self-heating strategy of lithium-ion battery at low temperatures based on bidirectional pulse current without external power

Polarization is a major problem for lithium-ion batteries (LIBs) at low temperatures. To realize rapid preheating of LIBs at low temperatures, a self-heating strategy based on bidirectional pulse current without external power is proposed. Four inductances and one direct current/direct current (DC/DC) converter are applied to the system. An electrothermal coupling model of LIBs and a performance evaluation model of the system are established to investigate the effects of circuit parameters and initial state-of-charge (SOC) on the heating performance, including the heating time, SOC utilization ratio (SUR), and heating efficiency. The results show that the LIBs can be warmed up from-10 degrees C to 0 degrees C in approximately 120 s. It is concluded that reducing the discharge induc-tance can increase the heating rate, SUR, and heating efficiency. However, the excessive reduction of the discharge inductance would cause a significant voltage drop, which will reduce the voltage to below the cut-off voltage. In addition, a comparative study shows that when the initial SOC values of the two battery packs are different, the heating time will be reduced. A higher initial SOC for one battery pack can increase the heating speed and SUR at the expense of the heating efficiency.

Automated summary

Polarization is a major issue for lithium-ion batteries at low temperatures. This study proposes a self-heating strategy using bidirectional pulse current to rapidly preheat batteries without external power. By establishing an electrothermal coupling model and a performance evaluation model, the effects of circuit parameters and initial SOC on heating performance were investigated.