Experimental study of large-area ultra-thin vapor chamber for microelectronic heat dissipation

Ultra-thin vapor chambers (UTVCs) are playing an important role in the cooling of microelectronic devices. However, the small area and low ultimate power of current UTVCs limit the performance evolution of integrated microelectronics. In this study, a large-area ultra-thin vapor chamber (204 x 143 mm) with an ultra-thin thickness of only 0.5 mm, referred to as LUTVC, is developed. The welding is carried out using low-cost brazing technology. The composite capillary wick for the LUTVC is a combination of the superhydrophilic multi-layer copper mesh and multiple spiral woven braids after the oxidation chemical treatment. The effects of filling ratio (FR) and different working conditions on LUTVC performance were investigated in detail. It is found that the 20 % FR LUTVC has the best thermal performance at low power (<= 50 W) with thermal resistance down to 0.12 degrees C/W, while the 30 % and 40 % FR LUTVCs have more advantages in heat dissipation at high power. The 30 % FR LUTVC combines the advantages of thermal conductivity and thermal power, with a high thermal conductivity of 13,237.2 W/(m.K) at 85 W and a maximum thermal power of 90 W. Thanks to its large heat dissipation area and ultra-high thermal conductivity, the novel LUTVC is an optimal element for power battery cooling. The LUTVC cooling solution reduces the average temperature, maximum temperature and temperature difference of the battery. The maximum temperature decreases by 2.1 degrees C and 6.7 degrees C compared to copper sheet at 1 C charging and 1.3 C charging, respectively, which improves the heat dissipation of new energy vehicle batteries.