Inconsistency analysis and comprehensive performance quantization of lithium-ion battery module configurations considering multi-factor cell-to-cell variation

Abstract

Understanding the inhomogeneity of the battery module is crucial for optimizing its performance and ensuring the safe operation of the energy storage system (ESS). This paper examines how various factors that can cause inconsistencies affect the modules' performance under two scenarios for ESS and conducts a comprehensive module performance evaluation. Initially, the influences of topology structure, connector resistance, temperature, and manufacturing tolerances are investigated. Different topologies exhibit distinct differences in various aspects of the module performance, especially State of Charge (SOC) consistency and temperature consistency. Among the remaining factors, connector resistance has the greatest impact on SOC consistency, while manufacturing tolerance exerts significant influence on discharge consistency and state of health consistency. The substantial impact of application scenarios on module temperature performance underscores the critical importance of considering both scenarios and topological configurations when designing thermal management systems. Subsequently, a comprehensive evaluation method is proposed, considering the distribution uncertainty of internal parameters and seven performance evaluation indicators. Using orthogonal experiments, the comprehensive performance score (CPS) of the four modules in scenario 1 is compared, considering the effect of operating conditions, design parameters, initial state, and manufacturing tolerance which indicates Cross-end has the highest CPS, 13.31 % higher than that of Ladder-up. Furthermore, in Scenario 2, a reasonable parallel connector resistance can enhance the CPS of the Cross-end module by 74.9 %. This research provides valuable insights into battery module inconsistency, which can significantly contribute to performance enhancement, thermal safety, and the optimization of design.