An FC (fuel cell) system includes: an FC; a radiator configured to cool a CL (cooling liquid); an ion exchanger provided in a BFP (bypass flow path) branched off from a CFP (circulation flow path) for allowing the CL to circulate between the FC and the radiator; a multi-way valve provided in a branching point at which the BFP is branched off from the CFP; and a pump which circulates the CL. A percentage of the CL that is made to flow through the BFP can be controlled by the multi-way valve. In a case in which a stop time is longer than a threshold time when the FC system is started up, after the CL is circulated through the radiator, the CL is circulated through the BFP at the percentage of 80% or more until electrical conductivity of the CL becomes smaller than a threshold electrical conductivity.

A fuel cell system includes: a fuel cell stack; a first cooling medium circuit through which a cooling medium for cooling the fuel cell stack flows; an ion exchanger that removes ions in the cooling medium; a second cooling medium circuit in which the average ion concentration of the cooling medium is lower than that of the cooling medium in the first cooling medium circuit; a switching valve that switches between a flow state and a low flow state; a pump configured to cause the cooling medium in the second cooling medium circuit to flow into the first cooling medium circuit; and a control unit that, when a stop period of the fuel cell system is longer than a reference period, drives the pump with the switching valve switched to the flow state after the instruction to start the fuel cell system is input.

A coolant control system of a fuel cell may include the fuel cell; a coolant line allowing a coolant to circulate therein and connected to the fuel cell to be heat-exchangeable with the fuel cell; an ion removal line provided with an ion filter and connected to a first portion and a second portion of the coolant line to allow a coolant branched from the first portion of the coolant line to pass through the ion filter and then flow into the second portion of the coolant line again; an adjusting valve adjusting a ratio between coolants respectively flowing into the coolant line and the ion removal line; and a controller engaged to the adjusting valve and configured for controlling the adjusting valve based on a temperature of the fuel cell or an output voltage of the fuel cell.

A fuel cell system FCS includes a fuel cell 10, a high voltage circuit 21 for driving an electromotor 42, and a relay 41 for electrically connecting or blocking the fuel cell 10 to or from the high voltage circuit 21. A control unit 50 obtains insulation decrease information in accordance with a request for starting the fuel cell, and performs, when a specified insulation decrease occurred region is not a fuel cell region SE1 including the fuel cell and the cooling circuit, conductivity reduction process on cooling liquid using a conductivity reduction unit 113 before having a relay 41 connect, and has the relay 41 connect after completing the conductivity reduction process.

A fuel cell system includes: a fuel cell stack; a first cooling medium circuit through which a cooling medium for cooling the fuel cell stack flows; an ion exchanger that removes ions in the cooling medium; a second cooling medium circuit in which the average ion concentration of the cooling medium is lower than that of the cooling medium in the first cooling medium circuit; a switching valve that switches between a flow state and a low flow state; a pump configured to cause the cooling medium in the second cooling medium circuit to flow into the first cooling medium circuit; and a control unit that, when a stop period of the fuel cell system is longer than a reference period, drives the pump with the switching valve switched to the flow state after the instruction to start the fuel cell system is input.

A fuel cell system FCS includes a fuel cell 10, a high voltage circuit 21 for driving an electromotor 42, and a relay 41 for electrically connecting or blocking the fuel cell 10 to or from the high voltage circuit 21. A control unit 50 obtains insulation decrease information in accordance with a request for starting the fuel cell, and performs, when a specified insulation decrease occurred region is not a fuel cell region SE1 including the fuel cell and the cooling circuit, conductivity reduction process on cooling liquid using a conductivity reduction unit 113 before having a relay 41 connect, and has the relay 41 connect after completing the conductivity reduction process.

A fuel cell system comprising a fuel cell stack is disclosed. An ozone generator is configured to introduce ozone into a coolant in the fuel cell system. A deionisation apparatus is coupled to the fuel cell stack. A bypass conduit is arranged in parallel with the deionisation apparatus. A controller is configured to control flow of the coolant to the fuel cell stack through either the deionisation apparatus or the bypass conduit based on the operating state of the ozone generator.

A fuel cell system comprising a fuel cell stack is disclosed. An ozone generator is configured to introduce ozone into a coolant in the fuel cell system. A deionisation apparatus is coupled to the fuel cell stack. A bypass conduit is arranged in parallel with the deionisation apparatus. A controller is configured to control flow of the coolant to the fuel cell stack through either the deionisation apparatus or the bypass conduit based on the operating state of the ozone generator.

An FC (fuel cell) system includes: an FC; a radiator configured to cool a CL (cooling liquid); an ion exchanger provided in a BFP (bypass flow path) branched off from a CFP (circulation flow path) for allowing the CL to circulate between the FC and the radiator; a multi-way valve provided in a branching point at which the BFP is branched off from the CFP; and a pump which circulates the CL. A percentage of the CL that is made to flow through the BFP can be controlled by the multi-way valve. In a case in which a stop time is longer than a threshold time when the FC system is started up, after the CL is circulated through the radiator, the CL is circulated through the BFP at the percentage of 80% or more until electrical conductivity of the CL becomes smaller than a threshold electrical conductivity.

An integrated fuel cell control system is provided. The integrated fuel cell control system includes at least one sensor, at least one hydrogen on/off valve, and a fuel control unit (FCU). The FCU is configured to directly operate the at least one sensor and the at least one hydrogen on/off valve in real time and to determine a supply pressure of hydrogen supplied to a fuel cell. Thereby, noise between controllers may be removed and costs may be reduced.