Experimental investigation of the thermal characteristics of a novel pure-metal-based flexible ultrathin vapour chamber

Abstract

The rapid development of high-performance flexible electronics requires novel metal-based flexible ultrathin vapour chamber (FUTVC) with higher heat transfer capacity to meet their heat dissipation needs. Although many works on flexible vapour chambers have been published, there are few works on metal-based flexible vapour chambers. Therefore, in this paper, a novel pure-metal-based FUTVC was proposed. Three kinds of FUTVCs were fabricated by brazing process and laser welding process, which were cost-effective processes suitable for mass production. The effect of manufacturing process, test direction and bending condition on the heat transfer performance of FUTVC was clarified, and the thermal mechanism of the FUTVC under bending conditions was theoretically analyzed. Results indicated that both laser welding and brazing can effectively seal the FUTVC. Wick sintered on the cover plate can effectively improve the thermal performance of the FUTVC. The maximum heat transfer capacity of the FUTVC in gravity state, horizontal state and anti-gravity state were 19 W, 16 W and 14 W, respectively. Furthermore, the maximum heat transfer capacity of the FUTVC with bending of 15°, 30°, 60° and 90° were 11 W, 10 W, 9 W and 8 W, respectively. The maximum effective thermal conductivity of the FUTVC was over 26000 W/(m•K) in horizontal state and over 10000 W/(m•K) under different bending conditions, which were approximately 65 times and 25 times higher than that of pure copper, respectively. The proposed novel FUTVC is promising for solving the heat dissipation problem of high performance ultra-thin flexible electronics.