Extracting the diffusion resistance and dynamic of a battery using pulse tests

The modeling of a battery by an equivalent circuit model requires the determination of its parameters. This determination can be done by exploiting the transient response of a battery to a current pulse (often called GITT: Galvanostatic intermittent titration technique). A classical approach is to first separate the open circuit voltage (OCV) and the overvoltage, and then to extract the model parameters from the latter. However, the estimation of the OCV can be difficult, which can lead to errors on the overvoltage, especially for slow dynamics such as diffusion. We propose here a method to estimate the OCV during GITT and a method to estimate the overvoltage which allow the extraction of parameters associated with slow dynamics. The results brought by the proposed method are compared with more classical approaches.

Automated summary

The modeling of a battery by an equivalent circuit model requires determining its parameters. This can be done by utilizing the transient response of a battery to a current pulse, often known as GITT. A common approach is to separate the OCV and overvoltage and extract the model parameters from the latter. However, estimating the OCV can be challenging, leading to errors in the overvoltage estimation for slow dynamics like diffusion. This study proposes a method to estimate the OCV and overvoltage during GITT, enabling the extraction of parameters associated with slow dynamics. The results are compared with traditional approaches.