In this study, the effects of applying graphene/polyurethane composite thermally conductive films on heat dissipation performance of capacitors were investigated. By adding graphene as a thermally conductive filler, the thermal conductivity of the composite film could be adjusted by controlling the type and content of the film. Graphene/polyurethane nanocomposite films with different mass fractions were prepared by adding 0.03, 0.06, and 0.3 wt. % graphene. The lattice and valence bond structures of the C atoms in the composite films were analyzed using x-ray diffraction, Raman spectroscopy, x-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy to investigate the extent of graphene defects and types of functional groups in the composite film materials. The thermal conductivity of the composite films was measured using a heat conduction analyzer, and the thermal diffusion coefficient was calculated. The steady-state thermal analysis showed that the capacitor with the composite film exhibited better thermal performance under the same conditions and significantly reduced the center temperature compared with those observed with other configurations. This study reveals the working mechanism of polyurethane/graphene composite thermal conductive film in the heat dissipation performance of capacitors. This study is of great significance for optimizing the design of capacitors, improving their efficiency, and maintaining long-term stable operation. By improving the thermal conductivity of composite films, capacitors with more uniform overall temperature distributions and reduced surface temperatures can be achieved, which will help improve the overall performance of capacitors and extend their service lives.

Thermal management is important for improving the safety, reliability, and service life of film capacitors operating under high-power conditions. In this study, graphene/thermoplastic polyurethane (TPU) composite films were prepared for capacitor heat dissipation. Physically modified graphene (G1) and chemically modified graphene (G2) were incorporated into TPU at loadings of 0.03, 0.06, and 0.30 wt%. The structural characteristics and chemical states of the films were investigated using X-ray diffraction (XRD), Raman spectroscopy, Fourier transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS). The thermal conductivity and thermal diffusivity of the composite films were evaluated, and a numerical model was used to investigate their effect on capacitor thermal behavior. The results showed that graphene incorporation preserved the major chemical structure of the TPU matrix while modifying its structural and surface chemical characteristics. The thermal response depended on both graphene type and loading. Among the tested samples, the 0.06 wt% G1/TPU film exhibited the highest measured thermal conductivity of 0.236 W/(m∙K). The thermal diffusivity showed a nonmonotonic dependence on graphene loading, with the maximum values obtained at 0.06 wt% graphene. Numerical results indicated that the thermally conductive film improved heat-flux uniformity and reduced the temperature gradient within the capacitor model. These findings demonstrate the potential of graphene/TPU composite films as flexible thermal-interface materials for capacitor thermal management.