An Intelligent Preheating Approach Based on High-Gain Control for Lithium-Ion Batteries in Extremely Cold Environment

In extremely cold climates, lithium-ion batteries suffer from a free-fall drop in the available capacity and useful life, which must be preheated before normal operations. The alternating-current (ac) heater has been developed by using buck-boost converters to achieve fast and consistent heating. However, it is difficult to preheat cold batteries rapidly without damaging them. Therfore, an intelligent preheating approach based on high-gain control is developed to adaptively adjust the ac heating current based on heating rate and battery temperature. Smaller ac heating currents are generated at lower battery temperatures and larger ac heating currents are generated at higher temperatures. In this way, the batteries can be preheated to a high temperature within a specified time without damaging battery health. Experimental results illustrate that the proposed approach has strong robustness and high reliability, which can effectively preheat low-temperature batteries under different conditions without the need of complicated battery model.