Development of a fast heat-transport system utilizing PCM and heat pipes

In this experimental study, a prototype system for transporting heat rapidly from a heat source. The system was a device combined with phase change material (PCM) and heat pipes. The prototype system was originally developed for an abnormal heat generation incident such as thermal runaway, of lithium-ion battery (LiB) in electric vehicles when the battery temperature exceeds 80°C. In the study, one cell or two cells of A4-sized LiB cells were actually short circuited in the prototype system, and the performance of the system was evaluated by measuring the cell temperature. Two kinds of PCM were tested in the experiments. The melting point of one of the PCMs was 50°C, and that of another PCM was 35°C. Moreover, to enhance heat transport inside the PCM itself, SiC powders were added to PCM to have larger thermal conductivities. From those experiments, it was understood that PCM played an important role for receiving rapid and large heat source in the initial period, and that heat pipes and heat sink devices became well activated after the initial period. The PCM with lower melting temperature was better in cooling the LiB cell. Moreover, the effect of increasing thermal conductivity of the PCM was remarkable after the LiB cell reached the maximum temperature. These fundamental results of the prototype system combined with PCM and heat pipes would be helpful when this idea is applied to other practical purposes.