Cell characteristics for 46Ah High Power Kokam Nano Pouch Cell

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 (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.

This dataset was created during a study on detection possibilities of cell faults thankfully funded by the European Automobile Manufacturers' Association (ACEA).

本研究通过对46Ah电池进行电化学阻抗谱（EIS）表征，以参数化R-RC-RC等效电路模型。测试样本在0°C、10°C、20°C、30°C、40°C的温度范围以及0%、10%、20%…、90%、100%的充电状态（SOC）下进行测量。原始数据经Matlab扩展DRTools分析，以识别最显著的时间常数。通过计算最大和最小时间常数的参数集（R1/C1、R2/C2），并利用虚阻抗的零交点进行插值，得到参数R。随后，利用SciPy优化器“L-BFGS-B”与DRT数据作为初始猜测，将模型拟合至数据。为此，通过最小化Nyquist图中模型阻抗与测量阻抗之间的欧几里得距离来实现。由于模型本身的局限性，拟合过程中未考虑具有正虚阻抗的测量点。电池的表征是通过在1A电流下，频率范围为[10mHz至100MHz]的恒电流EIS测量完成的。每十年度进行十次对数分布的测量。本数据集是在一项关于电池故障检测可能性研究的过程中创建的，该研究得到了欧洲汽车制造商协会（ACEA）的资助。