Low Temperature Preheating and Charging for Lithium-Ion Batteries through Dual Active Bridge Converter

Driven by the booming electric-vehicle market, lithium-ion cells have emerged as the principal on-board energy carrier, owing to their elevated energy density and balanceed overall performance. Their electrochemical behavior, however, degrades markedly in sub-zero environments, resulting in reduced usable capacity and operational efficiency. To address this issue, this paper proposes a low temperature internal preheating charging technique for lithium-ion batteries through DAB Converter. A second-order Thevenin-Type equivalent circuit is combined with a lumped thermal model so as to faithfully reproduce the dynamic electrical-Thermal response of the cell. A DAB converter is utilized to generate an alternating ripple current on its secondary side, which serves as an internal heat source to preheat the battery. An SOC-segmented multi-step constant-current charging law is subsequently formulated to guarantee both safety and efficiency throughout the charging process. Simulation results verify the feasibility and effectiveness of the proposed method, demonstrating improved charging performance and thermal uniformity under low-Temperature conditions.