Modeling changes in the state of charge-voltage waveform using regression parameters in a reduced-order physical model

摘要

A method for modeling changes in SOC OCV curves for a lithium ion battery cell as it ages. While charging the battery pack, voltage and current data for a battery cell is collected. A set of equations of state are used to determine the stoichiometry and state of discharge of the cathode half-cell based on the charging current profile over time. The voltage direction current data together with the stoichiometry and the state of charge of the cathode half cell are then used to estimate the maximum and minimum solids concentration values at the anode using an error function parameter regression / optimization. By calculating the stoichiometric conditions at both the cathode and the anode, cell capacity and a new SOC-OCV curve can be determined.