Abstract
This study applied the nonlinear ultrasonic method, second harmonic generation, to precisely estimate the state of charge (SoC) in lithium-ion batteries. The second harmonic of the longitudinal wave is generated on a pouch cell battery at 5 MHz with a through-transmission setup. The relative nonlinear parameter β ′ is determined by analyzing the amplitudes at the fundamental and second harmonic frequencies. To enhance the nonlinear parameter's measurement accuracy, multiple excitation amplitudes are employed. Two separate charge/discharge tests (four-cycle and eight-cycle) are conducted on the battery at a rate of C/10. The nonlinear parameter is measured periodically during the charge/discharge process, and temperature compensation is applied to the measurement. The correlation curves between the nonlinear parameter and the actual SoC align well for the four-cycle and eight-cycle tests, and a robust linear relationship is observed for both correlation curves. A linear model and a second-order polynomial model are applied to fit the correlation using all data points from both tests. The two models are employed to validate the SoC prediction on a second battery by using a four-cycle test. The results indicate that both models can predict the SoC with an accuracy of approximately 3%, whereas the polynomial model demonstrates smaller errors in the regions near 0% and 100% SoC. Therefore, the nonlinear parameter β ′ , measured through the second harmonic generation, can effectively predict lithium-ion battery SoC with an accuracy of less than 3%.
| Original language | English |
|---|---|
| Article number | 073902 |
| Journal | Applied Physics Letters |
| Volume | 124 |
| Issue number | 7 |
| DOIs | |
| State | Published - Feb 12 2024 |
Funding
This work was partially supported by Titan Advanced Energy Solutions and the National Renewable Energy Laboratory through the U.S. Department of Energy Lithium-Ion Battery Recycling Prize. Nitin Muralidharan and Kelsey Livingston are appreciated for their work on experimental setup and battery fabrication. Ryan Meyer and Georgios Polyzos are also acknowledged for their helpful comments on the earlier draft of the manuscript. This manuscript has been authored by UT-Battelle, LLC, under contract DE-AC05-00OR22725 with the U.S. Department of Energy (DOE). The U.S. government retains and the publisher, by accepting the article for publication, acknowledges that the U.S. government retains a nonexclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this manuscript or allow others to do so, for U.S. government purposes. DOE will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan ( http://energy.gov/downloads/doe-public-access-plan ).
