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Extracting information from time series data from rechargable batteries
Abstract
In practical applications such as electric vehicles, mobile phones, etc, rechargable batteries are continually charged and discharged, resulting in time-varying voltages and currents. The relationship between voltage and current depends on the properties of the battery and analysis of the time-series can yield useful information about battery performance. However, analysis is complicated because the charge-discharge cycles are not periodic or regular. For example, in an electric vehicle the battery might undergo intensive periods of discharge and charge, corresponding to acceleration and regenerative braking respectively, while the vehicle is in use, followed by long periods of inactivity. There is structure on the timescales of seconds through to days. We have recorded voltage, current and temperature of several batteries in a laboratory as they have been continually cycled over many months using both regular and irregular cycles, the latter mimicking cycles experienced in practical applications. We have used established methods of time-series analysis such as the Hilbert Transform to investigate the relationships between voltage and current, and have shown that results agree with more sophisticated but less practical methods of battery characterisation such as electrical impedance spectroscopy. The relationships imply that several different processes occur, depending on time-scale.
Type
Conference Contribution
Type of thesis
Series
Citation
Wilson, M., Cree, M., Scott, J., Dunn, C., & Farrow, V. (2023, September 13-15). Extracting information from time series data from rechargable batteries [Conference item]. Time Series Analysis of Noisy Data, Lancaster, UK.
Date
2023-09-15