The 2050 carbon‐neutral vision spawns a novel energy structure revolution, and the construction of the future energy structure is based on equipment innovation. Insulating material, as the core of electrical power equipment and electrified transportation asset, faces unprecedented challenges and opportunities. The goal of carbon neutral and the urgent need for innovation in electric power equipment and electrification assets are first discussed. The engineering challenges constrained by the insulation system in future electric power equipment/devices and electrified transportation assets are investigated. Insulating materials, including intelligent insulating material, high thermal conductivity insulating material, high energy storage density insulating material, extreme environment resistant insulating material, and environmental‐friendly insulating material, are categorised with their scientific issues, opportunities and challenges under the goal of carbon neutrality being discussed. In the context of carbon neutrality, not only improves the understanding of the insulation problems from a macro level, that is, electrical power equipment and electrified transportation asset, but also offers opportunities, remaining issues and challenges from the insulating material level. It is hoped that this paper envisions the challenges regarding design and reliability of insulations in electrical equipment and electric vehicles in the context of policies towards carbon neutrality rules. The authors also hope that this paper can be helpful in future development and research of novel insulating materials, which promote the realisation of the carbon‐neutral vision.

Metallised polypropylene film capacitors (MPPFCs) are widely used in power electronics and are generally degraded by elevated temperatures. This work aims to determine the relationships between the structural changes of MPPFC and the microstructural variations of the PP film during the thermal ageing of MPPFC at 100°C for 38 days. The capacitance of MPPFC has a slight decrease during thermal ageing. However, the breakdown voltage of the MPPFC decreases by 39.4% by the ageing. The partial discharge (PD) number of MPPFC increases linearly with ageing time. The tear‐down analysis of the MPPFC reveals that the molecular structure of the PP film has not been altered but has led to molecular chain scission and the generation of some polar fragments/groups. Meanwhile, the relative permittivity of the PP films rises as the ageing time increases. Moreover, thermal ageing causes the conversion of aluminum to alumina in the metallised electrode, which is hydrophilic for polar groups and leads to an adhesion effect between the metallised electrodes and the PP film. Contact angle measurements prove that the surface hydrophilicity of the PP sample increased after thermal ageing. Therefore, the PD/breakdown voltage in the MPPFC increases/decreases due to the uneven adhesion of the metallised PP film.