## 3 Results
### PCM and Liquid-Cooled Plate Block TR Propagation  
Figure 5a shows the comparison between the TR blocking experiments with only phase change composites and the experiments with liquid-cooled plates combined with phase change composites. In the combined blocking experiment, the first battery lost thermal control and exploded, emitting flames and smoke. After the TR combustion of the first battery ended, there was still a small quantity of white smoke flowing out, but in the second battery and the subsequent batteries, the TR phenomenon did not occur.  
Figure 5b shows the temperature characteristics of the TR propagation blocking experiment. When the composite phase change material insulation layer and the liquid cooling system worked together, the temperature of the first battery was slowly raised to about 400 \({}^{\circ}\)C by the action of the heater. After TR occurred, the surface temperature of the first battery suddenly rose to nearly 650 \({}^{\circ}\)C, and the rear surface suddenly rose to nearly 450 \({}^{\circ}\)C. At this time, due to the phase change endothermic effect of the composite phase change layer, the temperature of the front and back surfaces of the first section fell slightly, and the temperature of the front surface of the second battery was controlled at nearly 90 \({}^{\circ}\)C. After 100 s, with the consumption of the phase change materials, the composite phase change layer continued to have a heat insulation effect. After the front and back surfaces of the first battery reached the highest temperature, due to the existence of the thermal insulation layer, the speed of heat propagation to the second battery was significantly delayed, and the liquid cooling system could continue to cool the TR battery; the temperature continued to fall to below 250 \({}^{\circ}\)C, and the highest temperature of the front surface of the second battery was always maintained below 100 \({}^{\circ}\)C. The subsequent surface temperature of each battery  
Figure 4: (**a**) The physical images of different thermal insulation materials; (**b**) the SEM images of the three materials; (**c**) the temperature–time relationship of thermal diffusion of different thermal insulation materials.  
was always maintained at a low level, far below the critical temperature that triggers TR, and the TR propagation was successfully blocked.  
Figure 5c shows the maximum temperature characteristic of the TR propagation blocking experiment and the comparison with the previous experiment. It can be seen in the figure that, due to the combined effect of the composite phase change layer and the liquid cooling system, the maximum temperature of the surface after the first cell is controlled at about 500 \({}^{\circ}\)C; the maximum temperature of the front surface of the second battery is always below 100 \({}^{\circ}\)C, and the maximum temperature of the other surfaces is below 50 \({}^{\circ}\)C, which is far below the critical temperature for triggering TR.  
The safety prevention and control strategy integrates phase change composite materials with a liquid cooling plate. This approach does not require significant modifications to the existing protective structure of current new energy vehicles; instead, it only necessitates replacing the existing thermal insulation material with a new one. As a result, this strategy significantly reduces the cost associated with the adoption of new technologies and demonstrates high feasibility.