Volume estimating device, hydrogen filling device, and volume estimating method

A volume estimating device that, when a hydrogen tank of a vehicle is to be filled with hydrogen gas from a supplying portion of a hydrogen filling device, estimates a volume of the hydrogen tank,

• the volume estimating device comprising one or more processors that execute computer-executable instructions stored in a memory,
• wherein the one or more processors execute the computer-executable instructions to cause the volume estimating device to:
• acquire a first gas density inside the hydrogen tank based on gas pressure inside the hydrogen tank and a tank temperature at a first timing, and acquire a second gas density inside the hydrogen tank based on the gas pressure and the tank temperature at a second timing that is after the first timing;
• acquire a first corrected expansion rate obtained by correcting an expansion rate of the hydrogen tank in a prescribed state based on the gas pressure at the first timing, and acquire a second corrected expansion rate obtained by correcting the expansion rate based on the gas pressure at the second timing;
• acquire a total filling amount of the hydrogen gas that has filled the hydrogen tank from the hydrogen filling device in a period from the first timing to the second timing;
• estimate a volume of the hydrogen tank based on a volume of the supplying portion, the first gas density, the second gas density, the first corrected expansion rate, the second corrected expansion rate, and the total filling amount;
• judge whether the gas pressure exceeds a threshold value;
• and
• in a case where the gas pressure is judged to exceed the threshold value, estimate the volume of the hydrogen tank, and in a case where the gas pressure is judged to be less than or equal to the threshold value, not estimate the volume of the hydrogen tank.