Cryogenic inspection robots can perform various tasks in environments that are inaccessible to humans. Extreme cryogenic environments, such as space and deep sea, can cause irreversible damage to most conventional electronic components and mechanical parts. Therefore, energy-efficient thermal management technology is of great significance for cryogenic inspection robots and remains one of the technical challenges in this field. Phase change materials exhibits unique advantages, including high energy storage density and near-isothermal thermal management capabilities, making it highly valuable for thermal regulation. However, the energy storage mechanisms of phase change materials at ultra-low temperatures (-163℃) remain unclear, and the influence of phase change materials and spatial distribution on energy storage performance is not well understood. This study starts from the energy storage mechanism of cryogenic phase change materials. The temperature variations of different phase change materials under -163℃ conditions were examined, and the phase transition processes and energy storage efficiency were quantitatively analyzed. Experimental validation confirmed the accuracy of the analytical results, leading to the optimal selection of phase change materials. Furthermore, simulation studies were conducted to evaluate the energy storage performance of phase change materials at different scales and spatial distributions, followed by an analysis and optimization of their spatial arrangement. Finally, based on the studied phase change energy storage thermal management technology, a cryogenic inspection robot was designed and low-temperature inspection experiments were conducted. The results show that the inspection robot can carry out long-term inspection work at an ultra-low temperature of -163℃, verifying the feasibility of phase change energy storage thermal management technology and providing an effective technical approach for designing cryogenic inspection robots with efficient thermal management capabilities.