Research on Inconsistency Identification of Lithium-ion Battery Pack Based on Operational Data

Lithium-ion batteries have been widely used in the field of energy storage, due to the high energy density, wide temperature range and long service life. However, in application, the parameters such as the capacity and voltage of each cell in the battery pack are inconsistent due to unreasonable use, poor operating environment and other factors. In this paper, the qualitative relationship between the voltage variation of lithium-ion battery and the cell capacity and SOC is firstly analyzed, and then an inconsistent cell identification method is proposed based on three feature parameters of voltage outliers, voltage range and voltage difference. The static component is obtained from the voltage in the unstable discharge data by empirical mode decomposition and the inconsistency of capacity and SOC of static components is analyzed. The online identification of inconsistency of lithium-ion battery pack is realized based on the threshold and $K$ -means algorithm.