Experimental Results of Battery Power Capability Measurement on Cells with Different State of Health Levels

Abstract

Nowadays, lithium-ion batteries are widely used in electric vehicles (EVs). For safer and more efficient battery operation, a battery management system (BMS) that estimates the state of charge (SOC), state of health (SOH) and power capability (state of power, SOP) is required. Accurately estimating SOP is particularly challenging due to its susceptibility to various factors, including temperature, SOC, and aging. To gain insight into how various factors affect power capability, this study conducts an SOP measurement test throughout a battery aging test at two different temperatures. The SOP measurement technique utilized is developed from our previous patented work. Analysis of the impact of aging, SOC, SOH, and temperature on SOP dynamics are conducted. Furthermore, our study scales the cell-level results to a plug-in hybrid electric vehicle, offering practical insights into SOP estimation algorithms for usable energy and driving range scenarios. Given the absence of comparable data online, these experimental results serve as a valuable resource for developing an accurate power capability estimation algorithm.