Hybrid time frequency domain system and method for battery cell state estimation

A system comprising:

• data processing hardware;
• and
• memory hardware in communication with the data processing hardware, the memory hardware storing instructions that when executed on the data processing hardware cause the data processing hardware to perform operations comprising:
• measuring an initial temperature of a cell grouping in a vehicle;
• applying a perturbation to the cell grouping in the vehicle for a threshold period of time;
• measuring a perturbation temperature of the cell grouping and a voltage of the cell grouping;
• calculating, based on the measured perturbation temperature of the cell grouping and the measured voltage of the cell grouping, an entropy coefficient of the cell grouping;
• determining a plateau location based on the measured voltage of the cell grouping;
• generating a state of charge estimate based on the entropy coefficient and the plateau location;
• and
• splitting the state of charge estimate and the entropy coefficient into a material level state of lithiation and a material level entropy coefficient.