Gas filling method

1. A gas filling method for filling a tank with gas from an accumulator of the gas in a gas filling system,

the gas filling system including:

the tank;

the accumulator; and

a pipe configured to connect the accumulator and the tank, and supply the gas from the accumulator to the tank,

the gas filling method comprising:

setting a temperature separation pressure that is a pressure of the gas at which temperature separation occurs during filling of the tank with the gas;

detecting whether a pressure in the tank has reached the temperature separation pressure during the filling of the tank with the gas; and

filling the tank with the gas by increasing a pressure rise rate of the pressure in the tank after the pressure in the tank has reached the temperature separation pressure.

2. The gas filling method according to claim 1 , wherein

the pressure rise rate is increased in a manner so that the pressure in the tank falls within a pressure tolerance range.

3. The gas filling method according to claim 2 , further comprising filling the tank with the gas by decreasing the pressure rise rate in a manner so that the pressure in the tank falls within the pressure tolerance range before the pressure in the tank reaches the temperature separation pressure.

4. The gas filling method according to claim 1 , further comprising, after filling the tank with the gas by increasing the pressure rise rate, filling the tank with the gas by repeating a decrease of the pressure rise rate and an increase of the pressure rise rate.