The near-space solar-powered aerial vehicle is a long-endurance aircraft that uses solar energy as the source and is capable of continuous flight in near space. In recent years, the investigation of solar-powered aerial vehicles has become the focus of attention for many countries. The energy system is key in supporting the long-term operation of solar-powered aircraft, and achieving uninterrupted energy supply across the day and night is the primary objective in the research field of energy systems. Focusing on the main issues and research status in the development of clustered energy systems of near-space vehicles, the control objectives and multiple constraints of the energy system in the application scenario of the aircraft are sorted out first. Then the structure, function and modeling approaches of the clustered energy system are systematically discussed. Second, the state-of-the-art power-sharing, energy storage balance, and energy flow control under communication constraints in the clustered energy systems are summarized. And the achievements of reinforcement learning-based online energy scheduling are statemented. The effectiveness and shortcomings of existing strategies are further analyzed. Finally, the future trend and research direction of energy systems are discussed by considering the practical requirement for solar-powered aircraft.