Cell characteristics for 46Ah High Power Kokam Nano Pouch Cell
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A 46Ah cell was characterised by Electrochemical Impedance Spectroscopy (EIS) for parameterisation of a R-RC-RC equivalent circuit model. Samples were measured for all combinations of temperature (0, 10, 20, 30, 40°C) and state of charge (SOC) (0, 10, 20, …, 90, 100%). The raw data was analysed by the Matlab extension DRTools to identify the most dominant time constants. Using both biggest and smallest time constant one parameter set (R1/C1, R2/C2) was calculated. In addition, interpolating the zero-crossing point of the imaginary impedance give the parameter R. SciPy's optimiser "L-BFGS-B" was then used with the DRT data as initial guess to fit the model onto the data. For this, the Euclidean distance between model impedance and measured impedance in the Nyquist plot was minimised. Due to the limitations of the model used, measurement points with positive imaginary impedances were not considered during the fitting process. The cell was characterised by galvanostatic EIS measurement in the frequency range [10mHz to 100MHz] with a current of 1A. Per decade ten measurements were logarithmically distributed. Update (V2): Extension of the dataset by the corresponding open circuit voltage (OCV) for each SOC at 20°C. The data were obtained as pseudo-OCV by cycling the cell at a low current rate of C/20 (2,3 A). By averaging charge and discharge characteristic the given universal characteristic was determined. This dataset was created during a study on detection possibilities of cell faults thankfully funded by the European Automobile Manufacturers' Association (ACEA).
采用电化学阻抗谱（Electrochemical Impedance Spectroscopy, EIS）对该46Ah电池单体进行表征，以完成R-RC-RC等效电路模型的参数辨识。针对温度（0、10、20、30、40℃）与荷电状态（State of Charge, SOC）（0、10、20、…、90、100%）的所有组合工况，对测试样品开展了全量测试。原始数据通过Matlab扩展工具包DRTools进行分析，以识别占主导地位的时间常数。利用最大与最小时间常数，计算得到一组参数（R1/C1、R2/C2）。此外，通过对虚部阻抗的过零点进行插值运算，得到参数R。随后，以DRTools生成的数据作为初始猜测值，使用SciPy的优化器"L-BFGS-B"将模型拟合至实测阻抗数据。本次拟合以奈奎斯特图中模型阻抗与实测阻抗的欧氏距离最小化为优化目标。由于所用模型存在固有局限性，拟合过程中未纳入虚部阻抗为正的测量点。 该电池单体采用恒流电化学阻抗谱测试，测试频率范围为[10mHz至100MHz]，测试电流设定为1A。每个对数频程内以对数分布方式采集10个测试数据点。 版本更新（V2）：本数据集新增了20℃下各SOC对应的开路电压（Open Circuit Voltage, OCV）数据。该数据为以C/20倍率（2.3A）对电池进行循环测试得到的伪开路电压。通过对充放电特性曲线取平均，最终得到该通用特性曲线。 本数据集源于一项针对电池故障检测可能性的研究，衷心感谢欧洲汽车制造商协会（European Automobile Manufacturers' Association, ACEA）提供的研究资助。
