HEAT-GENERATION RATE AND GENERAL ENERGY-BALANCE FOR INSERTION BATTERYSYSTEMS

A general energy balance has been developed for insertion battery syst ems by using enthalpy potentials. This leads to a new calculation meth od for the heat-generation rater The same result is also derived from an alternative model based on local heat generation in an electrochemi cal cell. A new concept, the effective open-circuit potential of an in sertion battery, was proposed to characterize the open-circuit state o f the battery during galvanostatic discharge. Simulation results for a re presented heat generation in a lithium cell under galvanostatic dis charge. The analysis of these results focuses on effects of the shape of the open-circuit potential and ohmic losses in the electrolyte in t he porous cathode. It is shown that a single reaction may look like tw o reactions due to the presence of two plateaus in the open-circuit po tential.