Influence of Different Heat Transfer Structures on the Hydrogen Charging/Discharging Performance of Solid State Hydrogen Storage Tanks

Three types of heat transfer structures were constructed base on a LaNi₅-type rare earth-based hydrogen storage alloy as hydrogen storage medium by the method of strengthen heat conduction and mass transfer, and the heat transfer characteristics of each structure and their loading characteristics in solid state hydrogen storage tanks were measured. Importantly, we conducted the key research on hydrogen charging/discharging of solid state hydrogen storage tanks, then compared and evaluated the effect of three types of heat transfer structures on the hydrogen charging/discharging performance of the filled solid state hydrogen storage tanks, and thoroughly analyzed the heat conduction behavior of solid state hydrogen storage tanks during the hydrogen charging/discharging process using simulation methods finally. The results show that: The incorporation of aluminum and graphite, which are high thermal conductivity materials, as well as the unique design of heat transfer structures, extremely improve the thermal conductivity and hydrogen charging/discharging thermodynamic and kinetic level of solid state hydrogen storage tanks. Among the three types of heat transfer structures, RE09 particles/Al scrap/Al fins composite structure (structure-Ⅱ) exhibits the optimum hydrogen charging/discharging performance because of its stable structure and distinguished heat and mass transfer efficiency. Simulation results show that the temperature of three types of heat transfer structures decreasing gradually outward along the radius, which means that the core of the structures turn into the hottest zone, and the maximum temperature of RE09 particles/Al scrap/Al fins composite structure(structure-Ⅱ) and RE09 powder/expanded graphite powder compressed disks structure(structure-Ⅲ) is almost 400 ℃ lower than RE09 particles structure(structure-Ⅰ). Heat flux distribution connects closely with heat transfer structure form, excellent heat transfer structure design stimulates the heat flux flowing to the higher thermal conductive medium rather than gathering in alloy, and elevate the hydrogen charging/discharging kinetic level of solid state hydrogen storage tanks.