BACKGROUND

Exemplary embodiments pertain to the art of fuel cells, and in particular to hydrogen detection in fuel cell systems.

A flow of hydrogen rich, catalytically reformed fuel and a flow of oxygen or air are introduced to a fuel cell and chemically react to produce electricity and water. The reaction also produces heat, and a cooling system is utilized which circulates a water coolant stream through the fuel cell to remove the heat from the fuel cell. Reformed gas from the fuel can leak into the coolant stream, which can indicate internal cell stack failure and potentially cause a hazard due to the hydrogen content of the gas. The art would readily appreciate a means of detection of hydrogen in the coolant stream based on the reformed gas constituents to provide warning of the presence of hydrogen.

BRIEF DESCRIPTION

In one embodiment, a fuel cell system includes a fuel cell configured to produce electrical power by a chemical reaction of a flow of fuel and a flow of oxygen or air with an electrolyte and a cooling system configured to remove thermal energy from the fuel cell via a flow of coolant through the fuel cell. The fuel cell system includes one or more conductivity sensors configured to measure a change in conductivity of the coolant flow. The change in conductivity is indicative of a leak of the flow of fuel into the cooling system.

Additionally or alternatively, in this or other embodiments the one or more conductivity sensors detect a presence of carbon dioxide from the flow of fuel into the cooling system, the presence of carbon dioxide being indicative of a presence of hydrogen from the flow of fuel.

Additionally or alternatively, in this or other embodiments the cooling system includes a pump to urge the flow of coolant through the fuel cell, and a heat exchanger configured to reject thermal energy from the flow of coolant. A deionizing device is in the coolant stream to maintain a coolant cleanliness

Additionally or alternatively, in this or other embodiments the heat exchanger is a radiator/condenser.

Additionally or alternatively, in this or other embodiments the one more conductivity sensors includes a first conductivity sensor located fluidly upstream of the fuel cell to measure a first conductivity of the flow of coolant entering the fuel cell, and a second conductivity sensor located fluidly downstream of the fuel cell to measure a second conductivity of the flow of coolant exiting the fuel cell.

Additionally or alternatively, in this or other embodiments the flow of fuel is a blended fuel containing at least hydrogen and carbon dioxide.

Additionally or alternatively, in this or other embodiments a controller is operably connected to the one or more conductivity sensors and is configured to read increases in the measured conductivity indicative of a leak then take an action in operation of the fuel cell system based on detection of a leak in the flow of fuel into the cooling system.

Additionally or alternatively, in this or other embodiments the action is one or more of raising an alarm or stopping operation of the fuel cell system.

In another embodiment, a method of operating a fuel cell system includes producing electrical power at a fuel cell by a chemical reaction of a flow of fuel and a flow of air with an electrolyte, urging a flow of coolant through the fuel cell to remove thermal energy and ions from the fuel cell, and measuring a conductivity of the flow of coolant via one or more conductivity sensors. The conductivity increase is indicative of a leak of the flow of fuel into the flow of coolant.

Additionally or alternatively, in this or other embodiments a presence of increased carbon dioxide is detected via one or more conductivity sensors. The presence of carbon dioxide being indicative of a presence of hydrogen from the flow of fuel.

Additionally or alternatively, in this or other embodiments the flow of coolant is urged through the fuel cell via a pump, and thermal energy is rejected from the flow of coolant via a heat exchanger.

Additionally or alternatively, in this or other embodiments the one or more conductivity sensors includes a first conductivity sensor located fluidly upstream of the fuel cell to measure a first conductivity of the flow of coolant entering the fuel cell, and a second conductivity sensor located fluidly downstream of the fuel cell to measure a second conductivity of the flow of coolant exiting the fuel cell.

Additionally or alternatively, in this or other embodiments the flow of fuel is a blended fuel containing at least hydrogen and carbon dioxide.

Additionally or alternatively, in this or other embodiments an action is taken in operation of the fuel cell system based on detection of a leak in the flow of fuel into the cooling system.

Additionally or alternatively, in this or other embodiments the action is one or more of raising an alarm or stopping operation of the fuel cell system.

