Heat generation in lithium-ion batteries with different nominal capacities and chemistries

Highlights: • The effect of nominal capacity on heat generation in LIBs is significant. • Ratio of reversible to total heat in G/LCO LIBs is greater than G/LMO and in G/LMO LIBs is greater than G/LFP. • In G/LFP LIBs, anode activation & concentration polarization is >80% of total heat. • In G/LMO LIBs, anode activation & concentration polarization is >50% of total heat. • In G/LCO LIBs, anode activation & concentration polarization is >33% of total heat. - Abstract: Heat generation in lithium-ion batteries (LIBs), different in nominal battery capacity and electrode materials (battery chemistry), is studied at various charge and discharge rates through the multiphysics modeling and computer simulation. The model is validated using experimental results obtained in lab and the results reported by other researchers in literature. All sources of heat generation – including reversible heat generation and irreversible heat generation due to activation, concentration, and ohmic (electronic and ionic) polarizations – in LIBs with graphite/LiFePO₄, graphite/LiMn₂O₄, and graphite/LiCoO₂ electrode materials are quantified and the effects of the battery nominal capacity at various charge and discharge rates are studied. This study determines which sources of heat generation are significant and which sources of heat generation are negligible at different LIBs design and operating conditions. The contribution of LIB's different components including cathode, anode, separator, and current collectors in heat generation in LIBs is also determined. The results of this study assists battery engineers and researchers to characterize the thermal behavior of LIBs and have a much more exact prediction over the battery heat generation, leading to designing effective thermal management systems and providing accurate battery management systems for different applications of LIBs as well as cell design optimization and operation.