Thermal optimization of a kirigami-patterned wearable lithium-ion battery based on a novel design of composite phase change material

In this study, the thermal behavior of a stretchable lithium-ion battery following kirigami pattern is investigated and optimized online based on the finite element method. A novel distribution of expanded graphite/paraffin composite phase change material units, which is suitable for this unique battery, is proposed to reduce the temperature rise and improve the temperature uniformity at a high discharge rate of 5C. Before the optimization, a high dimensional modelling representation based global sensitivity analysis is performed to filter unimportant design variables to thermal management system, and a high quality metamodel is obtained by back propagation neural network. Instead of using trial-and-error method, the optimization is performed online by using different evolutionary multi-objective optimization algorithms, and the result obtained by strength Pareto evolutionary algorithm-II is shown to be the best. This optimal result shows that the thermal management system with optimized design exhibits great thermal performance. This study provides a guide for the design of battery thermal management of stretchable batteries.