Patent attributes
A fuel cell system comprises: a fuel cell stack (100) where an anode (110) and a cathode (120) are arranged under a state that an electrolyte membrane is positioned therebetween; a fuel tank (300) for storing a fuel; a fuel circulation supply means (400) for circulation-supplying a fuel stored in the fuel tank (300) to the anode of the fuel cell stack; an air supply unit (200) connected to the cathode of the fuel cell stack (100) by an air supply line, for supplying oxygen, etc. to the cathode (120); a sensing unit (500) for measuring a concentration of at least one of fuels supplied to the anode (110) and a control unit for receiving a signal of the sensing unit (500) and informing replacement time of a fuel. According to this, a fuel usage is maximized by informing replacement time of a used fuel and a filter (450) for filtering impurity by detecting a fuel consumption degree and an impurity generation amount.