Orthogonal design based pulse preheating strategy for cold lithium-ion batteries

The safety and availability of lithium-ion batteries are greatly affected by environmental temperature. Fast preheating of batteries is considered an effective technology for promoting the globalization of electric vehicles. This study establishes a coupled model of electro-thermal-aging to explore the advantages of pulse preheating methods in improving environmental adaptability and extending the service life of batteries. Firstly, the response of battery heating rate and capacity loss to the state of charge, positive pulse rate, pulse period, and the ratio of positive to negative pulse amplitude was analyzed. Additionally, the effects of various factors on the preheating effect of pulse current were explored. Secondly, appropriate factors and their levels were selected to construct an orthogonal experimental table. Then, the time and capacity loss rate were adopted as output response, multivariate analysis of variance and main effect analysis were performed on the factors and their levels in the orthogonal table. Moreover, the strategy of minimizing capacity loss and the shortest charging time for the pulse preheating method can be quickly determined based on the analysis results. Finally, the experimental results show that the developed preheating strategy achieves good results in terms of the heating effect and capacity retention rate.