A 1D electrochemical-thermal model of an electrode pair of a lithium ion battery is developed in Comsol Multiphysics. The mathematical model is validated against the literature data for a 10 Ah lithium phosphate (LFP) pouch cell operating under 1 C to 5 C electrical load at 25 °C ambient temperature. The validated model is used to conduct statistical analysis of the most influential parameters that dictate cell performance; i.e., particle radius ( $r_p$ ); electrode thickness ( $L_{pos}$ ); volume fraction of the active material ( ${\epsilon }_{s,pos}$ ) and C-rate; and their interaction on the two main responses; namely; specific energy and specific power. To achieve an optimised window for energy and power within the defined range of design variables; the range of variation of the variables is determined based on literature data and includes: $r_p$ : 30–100 nm; $L_{pos}$ : 20–100 μm; ${\epsilon }_{s,pos}$ : 0.3–0.7; C-rate: 1–5. By investigating the main effect and the interaction effect of the design variables on energy and power; it is observed that the optimum energy can be achieved when (r_p < 40 nm); (75 μm < L_pos < 100 μm); (0.4 < ε_s,pos < 0.6) and while the C-rate is below 4C. Conversely; the optimum power is achieved for a thin electrode ( $L_{pos}$ < 30 μm); with high porosity and high C-rate (5 C).

Cooling the surface of large format batteries with solid conductive plates, or fins, has an inherent advantage of reducing the number of liquid seals relative to some mini-channel cold plate designs, as liquid is not passed through the numerous individual plates directly. This may reduce the overall pack leakage risk which is of utmost importance due to safety concerns associated with the possibility of a cell short circuit and thermal runaway event. However, fin cooling comes at a cost of an increased thermal resistance which can lead to higher cell temperatures and a poorer temperature uniformity under aggressive heat generation conditions. In this paper, a novel graphite-based fin material with an in-plane thermal conductivity 5 times greater than aluminium with the same weight is presented for advanced battery cooling. The thermal performance of the fin is benchmarked against conventional copper and aluminium fins in an experimental programme cycling real 53 Ah pouch cells. The results from the extensive experimental testing indicate that the new fin can reduce both the peak measured temperature and surface temperature gradient by up to 8 °C and 5 °C respectively, when compared to aluminium fins under an aggressive electric vehicle duty-cycle.