To capture the change in specific heat capacity due to temperature in the model a function is needed to describe this relationship. The Debye theory of specific heat states that the specific heat of solids is proportional to 𝑇𝑇 3 if the temperature is below the Debye temperature, which is reported to be 141 °C for graphite and between 136 °C -204 °C for the transition metals in NMC. We can therefore fit the specific heat capacity against temperature data using third order polynomial according to Debye theory, it is important to capture these phenomena using scientifically-robust descriptions rather than arbitrary functions. The fits for the electrode powders and separator are illustrated in Figure with the comparison to raw data in Figure .