Comprehensive Design and Optimization of an Onboard Resonant Self-Heater for EV Battery

As the primary power sources of electric vehicles (EVs), lithium-ion batteries suffer from substantial capacity and power degradation at cold climates. An onboard battery preheater is essential for EVs to avoid degraded battery performance. This article proposed a resonant battery self-heater for internally preheating the batteries without external power supplies, thereby providing great flexibility for EVs in different parking areas. To achieve the optimized performance, a detailed analytical model of the self-heater is derived, illustrating the effects of the switching frequency and resonant tank parameters. Considering the size, heating speed, and efficiency, the detailed design methodology of the proposed self-heater is presented by utilizing a nonlinear optimization method, in which the battery impedance variation is included. The downscaled experiments on 18650 cells validate that the optimally designed self-heater can warm up the batteries from -20 degrees C to 0 degrees C rapidly with the minimum energy consumption compared with previous heating schemes.

Automated summary

This article proposes a resonant battery self-heater for electric vehicles to internally preheat the batteries without external power supplies, providing greater flexibility. Detailed analytical model and design methodology are presented to achieve optimized performance, considering battery impedance variation. Downscaled experiments validate that the optimally designed self-heater can rapidly warm up batteries with minimum energy consumption compared to previous heating schemes.