| Summary: | 碩士 === 元智大學 === 光電工程學系 === 104 === The topic of this study is about the insulating thermally-conductive composite phase change materials,(PCMs). We added carbon materials in the PCMs to enhance their thermal conductivity, but the carbon material may significantly reduce the resistance, which might result in short circuit of electronic components. Therefore , the carbon materials must be modified in order to enhance the insulation.
In this study, the PCM that was used was paraffin wax（Tm = 63°C）. And the carbon material, included homemade exfoliated graphite nanoplatelets（xGnP）and comercial graphene（G+）from Asfour. Then we used aluminum nitrate to modify the carbon materials by growth of alumina at the surface of the carbon material. The high insulation of alumina can overcome the high conductivity of earbon.
From the Hot Disk analysis of the xGnP, we found that its thermal conductivity can reach 9.06 W / mK. Differential scanning calorimetry（DSC）showed that G+-filled PCMs has a larger latent heat than xGnP-filled PCMs. And by four-point probe and insulation resistance tester , we found that the resistivity of the carbon material after modification significantly increased （from 101Ω-cm up to 1013Ω-cm）. Finally, in the PCM simulation test, we used a electric heating pad to simulation the high temperature environment of battery pack. We found that the composite PCM with a carbon fillers can quickly remove the heat, and prevent overheating and melting of the PCM.
From the above results, we found the optimal parameters, only a small content of modified carbon fillers can achieve both high insulation（1013 Ω-cm）, and high thermal counductivity（9.06 W / mK）. We believe our composite PCMs can find applications in the field of high-power battery packs, electronic components, or other product areas.
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