Research on a Lithium Deposition Prevention Control Strategy for an Onboard Self-Heater

Low-temperature preheating of lithium-ion batteries is an effective technical method to improve the low-temperature performance of lithium-ion batteries. In this paper, an onboard self-heater is investigated. It can obtain an asymmetric bi-directional pulsed heating current with a DC discharge component by controlling the inductor current. It is found that the DC/AC ratio of battery heating current increases with the inductor current, and there is a situation in which lithium deposition does not take place, regardless of the magnitude of the current. Then, the permissible inductor current amplitude at different temperatures was obtained based on the lithium deposition potential criterion and terminal voltage control criterion. Finally, the multi-stage constant-frequency variable-amplitude as well as multi-stage variable-frequency variable-amplitude heating strategies are proposed respectively. The simulation results indicated that both strategies can heat the battery from -20°C to 5°C within 605s.