摘要:
A system for the slow purge of a fuel cell stack. A pump can be used to keep the coolant circulating, so that the stack, an associated radiator, and coolant plumbing therebetween are maintained at the same temperature. The heat from the stack, liquid coolant, and radiator can be used to provide the heat of vaporization of the liquid in the stack, and the liquid water can be removed from the stack as water vapor. Because the air flow rate is relatively low, there is sufficient time for the water to vaporize and for the air to come to the same temperature as the stack, which is also facilitated by high surface area for heat transfer. Purge air can be drawn into the stack through the radiator, via a purge air blower, which preheats the air to help avoid frigid air contacting the stack.
摘要:
A system for the slow purge of a fuel cell stack. A pump can be used to keep the coolant circulating, so that the stack, an associated radiator, and coolant plumbing therebetween are maintained at the same temperature. The heat from the stack, liquid coolant, and radiator can be used to provide the heat of vaporization of the liquid in the stack, and the liquid water can be removed from the stack as water vapor. Because the air flow rate is relatively low, there is sufficient time for the water to vaporize and for the air to come to the same temperature as the stack, which is also facilitated by high surface area for heat transfer. Purge air can be drawn into the stack through the radiator, via a purge air blower, which preheats the air to help avoid frigid air contacting the stack.
摘要:
A method for determining the water transfer in a water vapor transfer unit of a fuel cell system that employs a model based approach. The method includes determining a capacity ratio of wet streams and dry streams flowing through the water vapor transfer unit, determining the number of mass transfer units of the water vapor transfer unit, estimating a mass transfer effectiveness value given the capacity ratio and the number of mass transfer units for the water vapor transfer unit, and determining the amount of water transferred in the water vapor transfer unit using the mass transfer effectiveness value, the mass flow rates on a dry basis of the dry stream and the wet stream, and the mass flow rates of water of the dry inlet stream and the wet inlet stream.
摘要:
An auxiliary coolant system, for a fuel cell stack system, includes a reversible coolant pump, a control valve, and plumbing lines. The pump enables the reversal of the coolant flow direction in the fuel cell stack system. The auxiliary coolant system is in parallel with the primary coolant system, and communicates with the primary coolant system via valves. During start-up, when coolant flow is from right-to-left through the fuel cell stack system, one valve of the primary coolant system will be partly open and control the amount of cold coolant make-up from the primary coolant system to the fuel cell stack while the valve of the auxiliary coolant system will be controlling the temperature differential between the inlet and outlet of the stack.
摘要:
A method for determining the water transfer in a water vapor transfer unit of a fuel cell system that employs a model based approach. The method includes determining a capacity ratio of wet streams and dry streams flowing through the water vapor transfer unit, determining the number of mass transfer units of the water vapor transfer unit, estimating a mass transfer effectiveness value given the capacity ratio and the number of mass transfer units for the water vapor transfer unit, and determining the amount of water transferred in the water vapor transfer unit using the mass transfer effectiveness value, the mass flow rates on a dry basis of the dry stream and the wet stream, and the mass flow rates of water of the dry inlet stream and the wet inlet stream.
摘要:
An auxiliary coolant system, for a fuel cell stack system, includes a reversible coolant pump, a control valve, and plumbing lines. The pump enables the reversal of the coolant flow direction in the fuel cell stack system. The auxiliary coolant system is in parallel with the primary coolant system, and communicates with the primary coolant system via valves. During start-up, when coolant flow is from right-to-left through the fuel cell stack system, one valve of the primary coolant system will be partly open and control the amount of cold coolant make-up from the primary coolant system to the fuel cell stack while the valve of the auxiliary coolant system will be controlling the temperature differential between the inlet and outlet of the stack.
摘要:
A bipolar plate for a fuel cell is provided that includes a pair of unipolar plates having a separator plate disposed therebetween. One of the unipolar plates is produced from a porous material to minimize cathode transport resistance at high current density. A fuel cell stack including a fuel cell and the bipolar plate is also provided.
摘要:
A fuel cell system is described having a fuel cell stack including a PEM fuel cell having an anode and a cathode, the fuel cell stack further including an anode outlet and an anode inlet, a hydrogen storage device in communication with the anode inlet and configured to supply a hydrogen gas to the fuel cell stack, and an accumulation reservoir in communication with the anode outlet of the fuel cell stack. The accumulation reservoir is configured to accumulate a quantity of water and an exhaust stream including the hydrogen gas during a purge event and resupply the exhaust stream to the fuel cell stack after the purge event is complete. The accumulation reservoir can be a second fuel cell stack. A method of operating the fuel cell system is also provided.
摘要:
A bipolar plate for a fuel cell is provided that includes a pair of unipolar plates having a separator plate disposed therebetween. One of the unipolar plates is produced from a porous material to minimize cathode transport resistance at high current density. A fuel cell stack including a fuel cell and the bipolar plate is also provided.
摘要:
A model uses various operating characteristics of a fuel cell to predict the relative humidity profile that is occurring within the fuel cell as a function of the reaction progress. The model is used to predict the relative humidity profile that will occur in response to changes to one or more of the operating characteristics of the fuel cell. A high frequency resistance of the fuel cell can also be used as a measure that is indicative of the humidity within the fuel cell. The model and/or the high frequency resistance can be used in a closed-loop feedback system to control the operation of the fuel cell to maintain the humidification of the MEA and fuel cells within a desired range to achieve a desired fuel cell performance.