Representing the Accumulator Ageing in an Automotive Lead-Acid Battery Model

This work deals with a mathematical model that represents a lead-acid battery during its useful lifetime. We have investigated the problem of determining the model from the non-invasive measurements of quantities like voltage, current, internal resistance, nominal capacity, and weight of the battery acquired for a batch of 12-V/70-Ah lead-acid batteries aged according to the procedures prescribed in the SAE J2801 standard. The test bench used in the experimental data acquisition consists of a battery cycler, a thermal bath, and true RMS multimeters. The proposed model includes an ageing term , a diffusion term , and an equivalent circuit. The errors for the “state of health”, “discharge capacity”, “internal resistance”, “open-circuit voltage”, and “overall mass” were smaller than 15, 4, 10, 1, and 0.6%, respectively. The agreement of the model predictions with the experimental results demonstrates the validity of the proposed model and the correctness of the underlying methodology. The main contribution of this model is that it represents the battery ageing by exploiting the experimental data acquired in the execution of the test protocol prescribed in the SAE J2801 standard.