Opportunities and Challenges of Employing Heat-Pipes in Thermal Management of Electrical Machines

Thermal management of power electronics, electrical machines and drives has become one of the key enabling factors in delivering of the future high-specific-output solutions for low-/zero-emission electrified propulsion. This paper reviews heat-pipe technology in application to electrical machines with focus on opportunities and challenges associated with successful deployment of such heat transfer/removal approach. Although, the use of heat pipes in electrical machines has been explored by numerous authors over decades of research, continuous developments in the materials and manufacturing techniques have opened new design avenues, with the high-rate heat transfer, low-added-weight, high-level of integration and reliability being some of the benefits of heat-pipe enabled cooling solutions. In this paper, underpinning fundamentals of the heat pipes construction and operation are discussed, with emphasis on the new/emerging solutions allowing for a more measured integration of heat-pipe-based or assisted thermal management systems in electrical machines. A number of examples of employing heat pipes in commercial and research applications are provided from the available literature together with the authors forecasts of the possible future technology advancement.