Impact of SEI layer thickness on lithium-ion battery cell surface temperature difference

This work aims to propose a new technique that would use the maximum surface temperature difference of a pouch cell to measure the thickness of the SEI layer. SEI can be one of the main causes of lithium-ion battery degradation at discharge rates of 0.1C – 1C with the ambient temperature close to room temperature.The pouch cell surface temperature difference changed due to significant SEI layer heat generation at several discharge rates. This temperature difference change was impacted by different cooling conditions.This work can help determine the SEI thickness inside the battery by measuring the surface temperature difference. This information can aid State-of-Health (SoH) estimation, extend battery life and help determine allowable operating conditions.