Structural design and performance of a large-capacity solid-state hydrogen storage tank incorporating internal honeycomb fins and an external thermal management jacket

Large-capacity solid-state hydrogen storage vessels face thermal management bottlenecks that severely restrict their scaling-up and efficient operation. To address this issue, this paper proposes an integrated thermal management structure comprising internal honeycomb fins and an external helical jacket to significantly enhance the hydrogen charging and discharging performance of large-capacity solid-state hydrogen storage vessels. Under a constant metal hydride loading, the thermal performance and reaction kinetics of the proposed honeycomb-finned reactor (HFR) and a conventional shell-and-tube reactor (STR) were systematically compared numerically. Furthermore, two external-jacket designs were evaluated, and an efficiency factor was used to determine the optimal inlet cross-section; finally, the key operating parameters were optimized. Numerical results indicate that after 8000 s of operation, the hydrogen uptake and release amounts of the STR reach only 74.79% and 93.16% of those achieved by the HFR, respectively. The spiral jacket provides more effective heat transfer than the serpentine layout. Compared with the HFR-J1, the bare reactor charged only 90.99% as much hydrogen and released just 74.25% as much. The full external jacket enables even the outermost alloy layers to participate effectively in the heating and cooling processes, thereby eliminating localized thermal imbalances. When the structural enhancements are coupled with the optimized operating parameters, a significant acceleration in both the charging and discharging rates is achieved. Finally, this study provides a practical and straightforward thermal management design blueprint for the industrial development of large-capacity metal hydride hydrogen storage vessels.