A study on the transient heat generation rate of lithium-ion battery based on full matrix orthogonal experimental design with mixed levels

Determination of the heat generation rate of the lithium-ion battery is crucial in both the design of battery thermal management system (BTMS) and prediction of the transient temperature rise during dynamic operation. In this work, the commercial cylindrical 18,650 lithium-ion battery with Ni-Co-Mn ternary positive materials was exemplified by the full matrix orthogonal experimental design to obtain the heat generation rate. The experiment with 176 over-potential tests and 66 entropy coefficient tests was conducted by taking into account the influencing parameters including the depth of discharge (DOD), discharge rate (DR) and ambient temperature. It was found that the heat generation rate exhibited minor variation for DOD=0 similar to 0.8 with slight decrease in the segment of DOD=0.3 similar to 0.6, and increased rapidly near the end of discharge (DOD=0.8 similar to 1). The average heat generation rate showed the approximate quadratic nonlinear correlation with discharge rate. In addition, the third-order transient heat generation rate model of the lithium-ion battery was correlated with all the influencing parameters by the response surface methodology (RSM). This work provides a detailed method for determining the heat generation rate of the lithium-ion battery, which lays foundation for predicting the temperature field of the battery and designing battery thermal management system.

Automated summary

This study determined the heat generation rate of the lithium-ion battery through experiments and data analysis, establishing the relationship between heat generation rate and influencing parameters. This provides a foundation for predicting battery temperature and designing thermal management systems.