Virtual Testbed for Economical and Reliability Analysis of Battery Thermal Management Control Strategies1

Abstract

A virtual testbed simulation framework is created for the economic, reliability, and lifetime analysis of battery thermal management control strategies in electric vehicles (EVs). The system-level model is created in the MATLAB environment using the Simscape library and custom components are developed as required. A lumped parameter coupled electrothermal model with temperature and state of charge (SOC)-dependent cell parameters is adopted from the literature to characterize battery performance. Suitable cell capacity degradation models are implemented to capture the cycle aging and calendar aging of the battery. The economic benefit of extending the lithium iron phosphate (LFP) battery lifetime by optimal thermal conditioning is weighed against the corresponding energy cost of the operation allowing for the assessment and adoption of economy-conscious strategies under different conditions. Active cooling of the battery using a vapor compression system along with a preconditioning strategy is benchmarked against passive cooling by a radiator for operating cost, battery lifetime, and net cost savings. Active cooling with precooling before fast charging can maintain optimal battery temperature but requires an additional electricity cost of 170–530 $/year, compared to passive cooling. However, the added cost is more than compensated for by the increase in battery lifetime by 1.4–1.9 years leading to a net saving of 140–550 $/year.