Abstract: With the wide application of power batteries in new energy vehicles, problems such as battery failure diagnosis and retired battery evaluation have to be solved urgently. Evaluating the state-of-health is a significant topic in the power battery field. Based on the analysis of the driving data of electric vehicles,a model is proposed which can evaluate the discharge performance of lithium-ion power batteries. According to the randomness of charge-discharge data in battery work, the adjustment and adaptation are carried out in the proposed model to solve the problem that the traditional evaluation method is difficult to apply to the real scenario. Due to its low complexity, it can give the evaluation results quickly, which is suitable for mass battery evaluation. Experiments show that the discharge performance index extracted by the proposed model decreases as the cumulative mileage increases, which has a similar trend with the change of battery capacity with mileage according to the grey relational analysis. It can evaluate the current discharge capacity of the battery from the actual work circumstance, and provide a reference for evaluating the state-of-health comprehensively.

Key words: power battery, driving data, discharge performance, evaluation model, state of health