## 3 Results and Discussion
### Numerical Modelling
#### 3.4.2 Temperature Predictions  
As outcome of the numerical simulations, the predicted temperature behaviour of cell 1 (or uncycled cell) at room and cycling temperatures are illustrated in Figures 20 and 21 during  
Figure 19: **(Upper)** Cycled cell voltage during high constant current discharge at 35 \({}^{\circ}\)C cycling temperature; **(Lower)** Absolute value of the voltage deviation between experimental and simulations data.  
Figure 18: **(Upper)** Cycled cell voltage during high constant current discharge at 25 \({}^{\circ}\)C room temperature; **(Lower)** Absolute value of the voltage deviation between experimental and simulations data.  
high constant current discharge (2C i.e., 40 A). From the comparison with the experimental measurements at three different locations (Top, Middle and Bottom regions), the absolute value of the temperature deviations are overall less than 1 and 2 \({}^{\circ}\)C, respectively. The good agreement in the simulated and the experimental data observed in Figures 20 and 21 translates for the accurate electrochemical-thermal characterisation and for the effective temperature predictions delivered by the coupled electrochemical-thermal modelling of the studied battery cells at room temperature. The temperature differences in the three regions indicate for non-uniform temperature distribution taking place at the surface of the battery cell. Further, these results emphasise the need for appropriate thermal management solutions that would on the long term decrease the battery ageing, by preventing the development of temperature differences at the surface of the battery cell (i.e., hot and cold regions).  
The predicted temperature behaviour of a cycled cell at room and cycling temperatures are illustrated in Figures 22 and 23 during high constant current discharge (2C i.e., 40 A). Predictions of the temperature distribution under 35 \({}^{\circ}\)C are illustrated in Figure 24. With these results, the higher temperature observed at the surface of the cycled battery cell, may be attributed to the rise in internal resistance, and hence in the heat generation inside the cell due to the ageing of the cell caused by long-term cycling. From the comparison with the experimental measurements at three different locations (Top, Middle and Bottom regions), the absolute value of the temperature deviations are overall less than 1.5 and 2 \({}^{\circ}\)C, respectively. In view of the results regarding cell 2 (or cycled battery) cell, less temperature uniformity is observed in Figure 23 compared to the case of an uncycled cell in Figure 21. The latter observation suggest for differences in the internal resistance of the cell in the different regions. Further thermal investigations might confirm this behaviour. The good agreement in the simulated and the experimental data observed in Figures 22 and 23 translates for the accurate electrochemical-thermal characterisation and for the effective temperature predictions delivered by the coupled electrochemical-thermal modelling of the studied battery cells at room temperature.  
Figure 20: **(Upper)** Uncycled cell surface temperature at three different locations (Top, Middle, Bottom) during high constant current discharge at 25 \({}^{\circ}\)C room temperature; **(Lower)** Corresponding absolute values of the temperature deviation between experimental and simulations data.  
Figure 21: **(Upper)** Uncycled cell surface temperature at three different locations (Top, Middle, Bottom) during high constant current discharge at 35 \({}^{\circ}\)C cycling temperature; **(Lower)** Corresponding absolute value of the temperature deviation between experimental and simulations data.  
Figure 22: **(Upper)** Cycled cell surface temperature at three different locations (Top, Middle, Bottom) during high constant current discharge at 25 \({}^{\circ}\)C room temperature; **(Lower)** Corresponding absolute values of the temperature deviation between experimental and simulations data.