An adaptive low-temperature mutual pulse heating method based on multiplexing converters for power-redistributable lithium-ion battery pack

Efficient and low-cost battery heating is particularly significant for recovering the available capacity and power of batteries at low temperatures. This paper proposes an adaptive mutual pulse heating (MPH) method to achieve the on-board heating of batteries, reusing the drive circuitry of batteries as heaters without any extra devices. To this end, a dual cubature Kalman filter-based co-estimator is developed based on an electrothermal model to capture battery state of charge (SOC), core temperature, and equivalent electrical parameters under rapid temperature-rise. The MPH current is updated online by the predicted maximum permissible charge/discharge current and the regulated heating duty ratio, which are formulated by considering multiple constraints and fuzzy feedback mechanisms. Experimental results show that with the MPH current profiles, batteries can be heated from −20 °C to 0 °C within 199.8 s, only consuming 5.99 % of cell capacity. Through capacity tests, increment capacity, and differential voltage analysis, there is no obvious battery degradation after 580 repeated heating cycles. Moreover, the preset heating period of less than 2 s has little impact on the heating duration, while when it is larger than 2 s, the heating duration increases with the heating period due to the inefficient heating.