Ultra-thin flexible heat pipe realized by composite structure flexible shell comprising channels and hemispheres

Conventional rigid heat pipes lack the flexibility to utilize their thermal management capabilities in flexible electronic devices with compact structures and dynamic cyclic bending. To solve the problem of flexible heat dissipation under complex working conditions, this paper proposes an ultra-thin flexible heat pipe (UTFHP) with composite structures and explores the potential application in artificial satellites. Using rapid mold forming, the flexible shell is fabricated with composite structure surfaces, including channel structures and hemispherical structures. The composite-structured flexible shell balances vapor flow space and cyclic bending performance, which enhances heat transfer device integration. The ultra-thin flexible heat pipe of 0.70 mm thickness with four kinds of structured pumping wicks were experimentally investigated. The results show that the composite-structured ultra-thin flexible heat pipe has efficient heat transfer capability at a bending angle of 0 degrees similar to 180 degrees, and the evaporator temperature fluctuation is less than 0.82 degrees C. A dynamic cyclic bending test at 45 degrees similar to 135 degrees was conducted, and it worked normally after 10,000 actions, with a thermal resistance value of 2.40 degrees C/W. The innovative combination of shape memory alloy (SMA) and UTFHP realizes the coupling function of the thermal actuator and radiator. In the execution and thermal management applications of artificial satellite photovoltaic panels (PV panels), SMA-UTFHP improves device integration and voltage output performance.