Measurement of the Heat Generation Rate of a Pouch Type Lithium-Ion Battery Using a Multifunctional Calorimeter

Abstract

Accurate characterization of the heat generation rate of lithium-ion batteries is critical for driving towards a cost-effective and efficient design of a thermal management system for various applications. Because of the increase in battery cell dimensions, as well as more aggressive operating conditions seen in the automotive industry, such as Direct Current Fast Charge (DCFC) and sustained driving under load, heat generation seen at the cell level must be considered as spatially non-uniform during operation. Proper design of the thermal management system requires measurement of the heat generation of the battery cell in both a lumped fashion for system sizing, as well as a distributed mode in order to tailor cooling appropriately to decrease local temperature extremes. Additionally, characterization of both the irreversible and reversible heat generation of the battery cell at various states-of-charge, temperatures, and states-of-life is required. Currently, few commercial calorimeters are available for the measurement of heat generation under dynamic conditions with a reasonable balance of accuracy and cost. In this work, we detail the development of a new calorimeter that allows for the measurement of the heat generation rate, determination of the irreversible and reversible heat generation, and rapid response time to capture dynamic cell responses.