Session: 10-01: Photovoltaic, Photovoltaic-Thermal, and Electrochemical Technologies I

Paper Number: 156368

156368 - Experimental Study of Li-Ion Batteries Performance Under Realistic Loads 

Abstract: 

The increasing adoption of renewable energy sources worldwide has stimulated a high demand for energy storage technologies. Electrochemical energy storage systems, such as batteries will play a pivotal role in the transition to a low-carbon economy. Understanding batteries performance over time, as a source of electricity demand for different applications, is crucial to improve the durability and reliability of these energy storage technologies. To achieve this objective, it is important to design and perform realistic testing approaches to track their performance and degradation under different circumstances in real world applications. The life of batteries is greatly affected by how they are used in real-world applications. Experimental studies of batteries degradation to analyze their longevity can be potentially time-consuming and misleading due to the faults of testing under simplified and not realistic conditions such as constant current, constant voltage (CC-CV) cycling which sometimes cover important information.  Our work aims to overcome these limitations of experimental studies using a Power-Hardware-in-the-Loop (PHIL) system. PHIL integrates real and simulated components in a controlled environment to test a wide array of electrical systems such as batteries under realistic conditions. Our experiments are conducted using an OPAL-RT real-time simulator, a device for PHIL technique that can execute real-time simulation of fast dynamics. This system is equipped with controllable power amplifiers as the basis of our tests. This state-of-the-art  system is capable of performing real charge and discharge cycling under real-world power profiles. We assess degradation rates and performance of lithium-ion batteries (LIBs) chemistries under realistic loads of standard drive cycling tests for electrical vehicles. We chose rechargeable cylindrical 18650 lithium-ion batteries to perform drive cycling tests. The changes in different parameters including capacity and unserved load of the examined LIBs have been monitored to assess the health of the system during the cycling experiments. We maintain safe operation and controls to ignore power requests that would cause the battery to reach voltages outside of the safe range. As capacity goes down over cycles due to the degradation, the unserved load in a given cycle goes up because the batteries hit the defined voltage limits faster. These results of health assessment were compared with the scenario in which we applied a ramp rate control to the drive cycling profile to smooth sudden power fluctuations and ensure stability. Our analysis will ultimately enable us to characterize the effects of ramp rate control on degradation rates such that we can develop effective methods to control and minimize the degradation rates of these systems. 

Presenting Author: Efat Mohammadi University of Memphis

Presenting Author Biography: Efat Mohammadi is a PhD candidate in Mechanical Engineering at the University of Memphis (U.S.A.), conducting research in the Energy System Control and Optimization (ESCO) Lab under the supervision of Dr. Alexander J. Headley.

Her research focuses on longevity, efficiency, and real-world performance of electrochemical energy storage systems, such as li-ion batteries and PEM water electrolyzers. Specifically, her work addresses a critical gap in understanding electrochemical degradation under realistic operating conditions. She is developing methodologies to isolate and analyze the real-time relationships between operational factors and degradation, with the goal of optimizing system control. This approach aims to enhance system performance and reliability through the application of advanced control techniques.