Preheatingstrategy ofvariable‐frequencypulse for lithium battery in cold weather

Abstract

Aiming to the issue of charging difficulty and capacity fading for lithium-ion battery at low temperature, this study proposes a preheating strategy using variablefrequency pulse. The innovation of this paper is to propose the thermo-electric coupling model based on the electrochemical impedance spectroscopy of battery at different temperatures, integrated with variable frequency changing for pulse method to develop an effective inner pre-heating strategy. Meanwhile, the evaluating method of impact of this strategy on capacity fading of battery has also been proposed to examine its effectiveness, to find the optimal strategy. First, temperature rise model and the thermo-electric coupling model at different temperatures according to the equivalent circuit model of battery are presented. Further, optimal heating frequency of current pulse at different temperatures is calculated according to the changing of internal impedance. The results show that the optimal variable-frequency pulse pre-heating strategy can heat the lithium-ion battery from −20 C to 5 C in 1000 seconds. Meanwhile, it brings less damage to the battery health and improves the performance of battery in cold weather based on the views of power consumption, capacity attenuation, and internal impedance changes.

A Review of the Power Battery Thermal Management System with Different Cooling, Heating and Coupling System

“…The comparative analysis found that mutual pulse heating not only consumes the least volume but also combines the advantages of internal uniform heating and no forced convection. Wu et al [57] proposed a thermoelectric coupling model based on electrochemical impedance spectra of batteries at different temperatures, combined with the pulse variable frequency method to formulate an effective internal preheating strategy, and developed a preheating strategy using frequency conversion pulses. The results show that the optimized frequency conversion pulse preheating strategy can heat the lithium-ion battery from −20 • C to 5 • C in 1000 s. At the same time, from the aspects of power consumption, capacity attenuation, internal resistance change, reduce the damage to the health of the battery, improve the performance of the battery in cold weather.…”

A review on battery thermal management and its digital improvement‐based cyber hierarchy and interactional network

“…The pulse preheating method uses pulse current to generate heat through the internal impedance of the cell to preheat the batteries. Compared with air preheating, the pulse preheating method can achieve a more uniform distribution of heat generation inside the battery pack, and a low‐temperature variance is beneficial to battery health 152 . An effective preheating strategy is developed using a thermo‐electric coupling model based on the EIS of the cell and the pulse frequency is varied between 1000 and 3637.1 Hz to compare their preheating effect.…”

“…Compared with air preheating, the pulse preheating method can achieve a more uniform distribution of heat generation inside the battery pack, and a low-temperature variance is beneficial to battery health. 152 An effective preheating strategy is developed using a thermo-electric coupling model based on the EIS of the cell and the pulse frequency is varied between 1000 and 3637.1 Hz to compare their preheating effect. The optimal pulse configuration (the 2637.5 Hz frequency) can heat the cell from À20 C to 5 C within 1000 seconds.…”