To enable automotive engineers to design such systems we have created a toolset (i.e. models) that can accurately reproduce the behaviour of such a HESS, in particular, the interactions between the battery and SC. Further, the tool is valid over a range of conditions known to affect system performance such as temperature. The tools are also validated with experimental data where the individual contributions of the battery and SC can be assessed.
A high-fidelity physically meaningful electrical Equivalent Circuit Model (ECM) of a supercapacitor is combined with a physical pseudo-3D thermal model. Separately, a physics-based battery model is generated and parameterised for an NCA 18650 cell. Model order reduction techniques are used to obtain an acceptable simulation time, resulting in a physics-informed electrical ECM which is subsequently coupled with a high-fidelity thermal model. Both models are individually validated across a range of operating conditions including temperature and current. The validated models are paired and the HESS model is validated over an automotive drive cycle with a particular emphasis placed upon battery current and temperature evolution. The generated toolset demonstrated that a HESS can provide superior performance to a battery only system for particular applications, however power availability limitations can cause highly detrimental effects for incorrectly sized systems, and hence good system design is critical.