Investigation of Thermal Properties of Lithium-Ion Batteries

The lithium-ion battery family (LCO, LMO, LFP, NMC) suffer thermally accelerated failure, making thermal management of the batteries and the batteries thermal properties important. At higher temperatures, the degradation of active phases accelerates, and thermal runaway becomes a safety concern. Battery degradation can be identified by analyzing the thermal properties of the cathode material. In this presentation, the transient hot wire method (THW) is applied to gauge the thermal conductivity of polycrystalline lithium nickel manganese cobalt oxide (NMC 811) as a function of the state of charge and cycles. The thermal properties of the uncycled baseline NMC811 electrode will also be discussed. Applications of this work to thermal management and battery diagnostics will be discussed.