Hydrogen Tank Filling Method Using Variable Flow Rates

The filling process is divided into multiple sequential steps with different flow rates. The method uses at least two filling steps where the first step operates at a higher flow rate to rapidly fill the tank when the temperature rise is less critical, and the second step operates at a lower flow rate to control temperature during the final pressurization phase. This segmentation of the filling process allows optimization of both filling speed and temperature control.

The filling flow rate is made dynamic rather than constant. The method adjusts the flow rate during the filling process, transitioning from a higher initial flow rate to a lower final flow rate. This dynamic adjustment allows the system to exploit the thermal capacity of the tank during rapid filling while preventing excessive temperature rise as the tank approaches its final pressure, thereby resolving the contradiction between filling speed and temperature control.

The filling operation is segmented into phases with different thermal characteristics. The first phase uses high flow rate when the tank has sufficient thermal capacity to dissipate heat, and the second phase uses lower flow rate when the tank is more susceptible to temperature rise. This segmentation allows the system to maximize filling speed during phases where heat dissipation is adequate while preventing thermal damage when heat dissipation becomes insufficient.

The method performs preliminary rapid filling when the tank is cooler and has better heat dissipation capacity, before the temperature rise becomes problematic. By anticipating the thermal limitations and acting accordingly, the system maximizes the useful filling time while preventing the harmful effect of insufficient heat dissipation during critical phases.

The method uses a high flow rate in the first filling step at excessive levels compared to what would be used for the entire process, deliberately allowing faster filling when thermal conditions permit. This partial excessive action is followed by a lower flow rate step to complete the filling, achieving optimal balance between temperature control and filling time by using high flow rate only when necessary and safe.

The filling parameters, specifically the flow rate, are changed during the process based on thermal considerations. The method transitions from a high flow rate parameter to a lower flow rate parameter as the filling progresses and thermal conditions change. This dynamic parameter adjustment allows the system to maintain good temperature control while minimizing the penalty on filling time that would result from using a consistently low flow rate.