Patent ID: 9297718
Filing Date: 2016-03-29
CPC Classification: G01M,H01M,Y02E

Claim Text:
1. A method for checking gas tightness of a fuel cell system which has a fuel cell and a container for storing hydrogen gas, the method comprising: using a pressure sensor on a line connecting the container to the fuel cell to measure a pressure of hydrogen gas flowing to the fuel cell in the line; calculating a quantity of hydrogen gas flowing to the fuel cell using a quantity/pressure relationship which describes a relationship between pressure and quantity of hydrogen gas; measuring a current generated by the fuel cell; calculating a quantity of hydrogen gas which has been converted into electricity by the fuel cell using a quantity/current relationship which describes a relationship between current generated by the fuel cell and quantity of burnt hydrogen gas; comparing the quantity of hydrogen gas flowing to the fuel cell with the quantity of hydrogen gas which has been converted into electricity; detecting a leak if the quantity of hydrogen gas flowing to the fuel cell is greater than the quantity of hydrogen gas which has been converted into electricity; measuring a temperature of the container to determine a temperature of hydrogen gas in the container; comparing the temperature of hydrogen gas with a temperature of surrounding air and determining a throughput rate of hydrogen gas for the container based on a Joule-Thomson effect; if the container is closed and the temperature of the container differs from the temperature of the surrounding air, detecting a leak in the container based on the Joule-Thomson effect; and controlling the fuel cell system to take remedial action in response to detecting the leak if the quantity of hydrogen gas flowing to the fuel cell is greater than the quantity of hydrogen gas which has been converted into electricity, or in response to detecting the leak in the container based on the Joule-Thomson effect if the container is closed and the temperature of the container differs from the temperature of the surrounding air.