Rapid warm-up strategy for lithium-ion batteries based on temperature uniformity model of sandwich self-heating structure in multiple scenarios

Lithium -ion battery heating technology is a crucial enabler for electric vehicles to operate in cold climates. Ensuring the delicate balance between temperature rise rate and temperature uniformity faces unprecedented challenges due to the poor thermal diffusivity of batteries. In order to overcome the challenges, first of all, this study proposes a sandwich self -heating structure for lithium -ion batteries and establishes a temperature uniformity model during the heating process of sandwich self -heating structure batteries. Then, the effects of duty cycle on temperature uniformity and heating rate are analyzed. Finally, a rapid warm-up strategy considering temperature uniformity is proposed to reconcile the contradiction between heating rate and temperature uniformity. The proposed rapid warm-up strategy can shorten the heating time by 16 % under three typical heating scenarios. Furthermore, the proposed strategy is applied to two other sandwich self -heating structures with different batteries, and the results show that the rapid warm-up strategy can significantly reduce the heating time and has the potential to be promoted in different types of batteries.