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Thermal characteristics of lithium-ion battery cells are crucial in the thermal design of power battery packs for electric vehicles. In this paper, a calibration calorimetry method of considering the heat loss is proposed to investigate the thermal characteristics of a commercial cylindrical 21700 cell. In the meantime, an existing heat-flux meter method is employed to analyze the present method effectiveness. Furthermore, a cell thermal model by considering the physical specifications and thermal parameters is established to predict the cell's temperature rise during its operation. It is shown that the proposed calibration calorimetry method matches well with the existing heat-flux meter method in determining the cell heat generation rate. The cell heat generation rate increases as the decreasing temperature and the increasing discharge rate, and there exists a quadratic-relationship in them between each other. The established thermal model to predict the cell temperature rise is effective with accuracy of within 3.0 °C. This work is fast and cost-effective in characterizing the thermal characteristics of the commercial cylindrical cells, without resorting to the specialized instruments. • A calibration calorimetry method to analyze cell thermal characteristics is proposed. • The present method is compared with the heat flux meter method. • Cell heat generation is increased at ascending discharge rate and lower temperature. • The established thermal model predicts cell temperature profile is highly feasible. [ABSTRACT FROM AUTHOR]

The thermophysical parameters such as thermal conductivity and specific heat play a vital part in the thermal design of the power battery pack composed of cylindrical lithium ion battery cells. This work proposes a quasi steady state method with considering heat loss to measure the thermophysical parameters of two classes of 21700 and 18650 cylindrical cells, respectively. To this end, the theoretical model and the corresponding measurement method were developed in consideration of the heat loss, and the two cells' thermophysical parameters were experimentally determined over a wide operating temperature range of −20–60 °C. The results show that both of the thermal conductivity and the specific heat of the cells increase linearly with the increase of the operating temperature. In comparison, the cell temperature has a greater influence on the specific heat than that of the thermal conductivity. The experimental verification reveals that the measurement error is behind 5.1%. Having a short measurement time within 930s, the present work provides a fast and convenient solution on determining the thermophysical parameters of the cylindrical cells without resorting to the costly instruments. • Proposes a quasi steady state method to measure cylindrical cell thermal parameters. • Cost-effectiveness and fast in current method to derive the cell thermal parameters. • Cell thermal parameters linearly increase as increasing temperature of −20–60 °C. • Experimental verification reveals that the current method is highly feasible. [ABSTRACT FROM AUTHOR]