Fuel cell anode circulation system and control method thereof

Abstract

The invention discloses a fuel cell anode circulating system and a control method thereof, in the fuel cell anode circulating system, a turbine compressor comprises a turbine end and a gas compression end connected with the turbine end; the hydrogen storage bottle is connected with the hydrogen pretreatment mechanism; the hydrogen pretreatment mechanism is respectively connected with the first proportional valve and the second proportional valve; the first proportional valve is connected with a turbine end inlet, and a turbine end outlet is connected to an anode inlet of the electric pile; the second proportional valve is connected with a high-pressure gas inlet of the ejector, and a mixed gas outlet of the ejector is connected to the anode inlet; an anode outlet of the electric pile is connected with a compressed air end inlet, and a compressed air end outlet is connected with a low-pressure air inlet of the ejector. According to the invention, the working range of the anode circulation system is widened, the overall efficiency of the system is improved, the requirements of all working conditions of the fuel cell on the anode circulation path are covered by defining three control modes, the high-pressure hydrogen energy is utilized to the maximum extent, the anode circulation system is more flexible to control, and the system is high in operation stability and robustness.

Description

Technical Field

[0001] The present invention belongs to the technical field of fuel cells, and in particular relates to a fuel cell anode circulation system and a control method thereof. Background Art

[0002] The low-temperature proton exchange membrane fuel cell system uses air (oxygen) and hydrogen as reaction media to generate electricity through electrochemical reactions in the stack. In order to ensure sufficient supply of hydrogen, that is, the reaction gas on the anode side of the stack, an oversupply is generally used, and in order to achieve higher system economy, hydrogen circulation is used.

[0003] The traditional anode circulation system uses a circulation pump or an ejector. The circulation pump uses electricity to drive the motor to drive the rotor impeller to compress and transport the gas. The ejector is a venturi tube that uses high-pressure hydrogen to intercept the critical flow and suck out the unreacted secondary flow. Although both the circulation pump and the ejector can achieve the purpose of anode circulation, they each have disadvantages: (1) The circulation pump increases the power consumption of auxiliary parts, reduces the overall efficiency of the system, has high power costs, and has reliability and life issues with components under long-term high loads; (2) The ejector is a passive component and cannot be controlled. It cannot provide circulation flow when the electric density is low and there is no supersonic flow, and it cannot break ice at low temperatures.

[0004] Invention patent application CN109921061A discloses a fuel cell gas supply system and gas supply method. This patent uses a turbo compressor in the process of reducing the pressure of high-pressure hydrogen in the fuel cell, but the pressure end is the cathode gas supply, that is, the high-pressure potential energy of hydrogen is used to drive the turbine to drive the air compressor. In this patent, in high-power scenarios, the air compressor has high power, the hydrogen pressure potential energy is limited, the utilization efficiency is low, the benefits are low, and the shaft end hydrogen and air sealing problems need to be solved, so the practical value is low.

[0005] Utility model patent CN218160482U discloses an anode circulation pump assembly and a fuel cell system for a fuel cell system. This patent discloses a fuel cell anode circulation assembly that uses the potential energy of cathode exhaust gas pressure to drive a turbine to drive a hydrogen compressor. It also needs to solve the hydrogen-air shaft end sealing problem. The system integration design needs to consider the direct connection of the cathode turbine and the hydrogen compressor shaft end, which will become more complicated. Summary of the invention

[0006] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a fuel cell anode circulation system and a control method thereof, which broadens the operating range of the anode circulation system and improves the overall efficiency of the system. By defining three control modes, the requirements of the fuel cell for the anode circulation circuit under all operating conditions are covered, and the utilization of high-pressure hydrogen energy is maximized. The control of the anode circulation system is more flexible, and the system operation is highly stable and robust.

[0007] The present invention provides the following technical solutions: In a first aspect, a fuel cell anode circulation system is provided, comprising a hydrogen storage bottle, a hydrogen pretreatment mechanism, a first proportional valve, a second proportional valve, a turbo compressor, an ejector and a fuel cell stack, wherein the turbo compressor comprises a turbine end and a compressor end connected to the turbine end; The hydrogen storage bottle is connected to a hydrogen pretreatment mechanism, and an outlet end of the hydrogen pretreatment mechanism is respectively connected to a first proportional valve and a second proportional valve; The first proportional valve is connected to the turbine end inlet, and the turbine end outlet is connected to the anode inlet of the fuel cell stack; The second proportional valve is connected to the high-pressure gas inlet of the ejector, and the mixed gas outlet of the ejector is connected to the anode inlet; The anode outlet of the fuel cell stack is connected to the compressed gas inlet, and the compressed gas outlet is connected to the low-pressure gas inlet of the ejector.

[0008] Furthermore, a pressure reducing valve is connected between the hydrogen storage bottle and the hydrogen pretreatment mechanism.

[0009] Furthermore, the hydrogen pretreatment mechanism comprises a plate heat exchanger, and the plate heat exchanger is provided with a refrigerant inlet, a refrigerant outlet, a heat medium inlet and a heat medium outlet; The refrigerant inlet is connected to the pressure reducing valve, the heat medium inlet is connected to the coolant outlet of the fuel cell stack through a heat medium inlet pipe, and the heat medium outlet is connected to the coolant inlet of the fuel cell stack through a heat medium outlet pipe.

[0010] Furthermore, the hydrogen pretreatment mechanism also includes a hydrogen filter, the inlet end of the hydrogen filter is connected to the refrigerant outlet, and the outlet end of the hydrogen filter is respectively connected to the inlet end of the first proportional valve and the inlet end of the second proportional valve.

[0011] Furthermore, it also includes a water separator, the inlet end of the water separator is connected to the anode outlet of the fuel cell stack, and the gas outlet end of the water separator is connected to the compressed gas inlet; the liquid outlet end of the water separator is provided with a drain valve, and the side or top of the water separator is provided with a nitrogen exhaust valve, and the outlet ends of the drain valve and the nitrogen exhaust valve are both connected to the tail drain pipe.

[0012] Furthermore, a first pressure sensor is provided at the anode inlet of the fuel cell stack, a second pressure sensor is provided at the anode outlet of the fuel cell stack, and a third pressure sensor is provided at the gas outlet end of the water separator.

[0013] Furthermore, the anode inlet of the fuel cell stack is connected to an anode inlet pipe, and the mixed gas outlet of the ejector and the outlet of the turbine end are both connected to the anode inlet pipe and communicate with the anode inlet of the fuel cell stack through the anode inlet pipe.

[0014] In a second aspect, a control method for the anode circulation system of the fuel cell according to the first aspect is provided, comprising: Determine the operating current of the fuel cell stack and the hydrogen inlet pressure and circulation flow requirements; When the stack is in low current operation, the first proportional valve is opened and the second proportional valve is closed. The stack pressure is controlled by adjusting the first proportional valve, and the circulation flow is controlled by adjusting the speed of the compressor end. When the stack is in medium current operation, the first proportional valve is fully opened, the second proportional valve is opened, the stack inlet pressure is controlled by adjusting the second proportional valve, and the circulation flow is controlled by adjusting the speed of the compressor end; When the fuel cell stack is running at high current, the first proportional valve is opened and the second proportional valve is fully opened. The pressure entering the stack is controlled by adjusting the first proportional valve, and the circulation flow is controlled by adjusting the speed of the compressor end.

[0015] Furthermore, when the fuel cell stack is in low current operation, the new hydrogen in the hydrogen storage bottle enters the turbine end of the turbo compressor after being processed by the hydrogen pretreatment mechanism, so that the turbine end drives the compressor end to suck and compress the circulating hydrogen output from the anode outlet of the fuel cell stack. After the compressed circulating hydrogen flows through the ejector, it is mixed with the new hydrogen output from the turbine end outlet and enters the fuel cell stack through the anode inlet of the fuel cell stack to participate in the reaction. When the fuel cell stack is in medium current operation, the new hydrogen in the hydrogen storage bottle is processed by the hydrogen pretreatment mechanism, and most of it enters the turbine end of the turbo compressor, and a small part enters the ejector through the high-pressure gas inlet of the ejector, and is output from the outlet of the turbine end and the mixed gas outlet of the ejector, and enters the fuel cell stack through the anode inlet of the fuel cell stack; at the same time, the turbine end recovers the energy of the new hydrogen and drives the compressor end to suck and compress the circulating hydrogen output from the anode outlet of the fuel cell stack. Due to the influx of high-pressure hydrogen, the ejector provides auxiliary suction capacity for the circulating hydrogen, so that the compressed circulating hydrogen flows through the ejector and enters the fuel cell stack through the anode inlet of the fuel cell stack to participate in the reaction; When the fuel cell stack is operating at high current, the new hydrogen in the hydrogen storage bottle is processed by the hydrogen pretreatment mechanism, and most of it enters the ejector through the high-pressure gas inlet of the ejector, and a small part enters the turbine end of the turbo compressor, and is output from the outlet of the turbine end and the mixed gas outlet of the ejector, and enters the fuel cell stack through the anode inlet of the fuel cell stack; at the same time, due to the influx of high-pressure hydrogen, the ejector provides the main suction capacity for the circulating hydrogen output from the anode outlet of the fuel cell stack, the turbine end recovers the energy of the new hydrogen and drives the compressor end to assist in the suction and compression of the circulating hydrogen, and the compressed circulating hydrogen flows through the ejector, and enters the fuel cell stack through the anode inlet of the fuel cell stack to participate in the reaction.

[0016] Furthermore, when the fuel cell stack is loaded, the control method includes: Determine the operating current of the fuel cell stack and the hydrogen inlet pressure and circulation flow requirements; Enter the low current operation mode of the fuel cell stack, open the first proportional valve, close the second proportional valve, control the stack pressure by adjusting the first proportional valve, and control the circulation flow by adjusting the speed of the compressor end; Determine whether the stack pressure and circulation flow meet the requirements. If so, continue to determine whether the stack voltage and single chip consistency meet the required indicators. If so, end the control; If the stack pressure and circulation flow rate do not meet the requirements or the stack voltage and single chip consistency do not meet the required indicators, the stack current operation mode is entered, the first proportional valve is fully opened, the second proportional valve is opened, the stack pressure is controlled by adjusting the second proportional valve, and the circulation flow rate is controlled by adjusting the speed of the compressor end; Determine whether the stack pressure and circulation flow meet the requirements. If so, continue to determine whether the stack voltage and single chip consistency meet the required indicators. If so, end the control; If the stack pressure and circulation flow rate do not meet the requirements or the stack voltage and single chip consistency do not meet the required indicators, the stack high current operation mode is entered, the first proportional valve is opened, the second proportional valve is fully opened, the stack pressure is controlled by adjusting the first proportional valve, and the circulation flow rate is controlled by adjusting the speed of the compressor end; Determine whether the stack pressure and circulation flow meet the requirements. If so, continue to determine whether the stack voltage and single chip consistency meet the required indicators. If so, end the control; If the stack pressure and circulation flow do not meet the requirements or the stack voltage and single chip consistency do not meet the required indicators, the fault will be shut down and the control will end.

[0017] Furthermore, the hydrogen inlet pressure P_stkin is obtained through a first pressure sensor provided at the anode inlet of the fuel cell stack; The inlet pressure P_stkout of the water separator is obtained by a second pressure sensor provided at the anode outlet of the fuel cell stack, and the outlet pressure P_sepout of the water separator is obtained by a third pressure sensor provided at the gas outlet of the water separator. Then, the flow resistance dP_sep of the water separator is P_stkout-Psepout, and the circulating flow rate of hydrogen is M_recir=F(dP_sep,I0), wherein I0 is the fuel cell stack current.

[0018] Compared with the prior art, the present invention has the following beneficial effects: (1) The fuel cell anode circulation system provided by the present invention includes a turbo compressor, which includes a turbine end and a compressor end connected to the turbine end. The turbine end can fully recover the pressure potential energy of high-pressure hydrogen. The compressor end is driven to work by the turbine end, which solves the waste of hydrogen pressure potential energy on the one hand, and reduces the power demand of the compressor end on the other hand, reduces the cost of the turbo compressor, and improves the system efficiency; (2) The fuel cell anode circulation system provided by the present invention includes an ejector, which is connected in series with the compressor end of the turbo compressor, which can increase the flexibility of operating condition control, broaden the working range of the anode circulation system, reduce costs, reduce the power consumption of auxiliary components, and improve the overall efficiency of the system; (3) In the fuel cell anode circulation system provided by the present invention, the turbo compressor and the ejector are both located at the anode circulation end, that is, in a hydrogen environment, and there is no need to solve the hydrogen-air shaft end sealing problem, thus avoiding the risk of gas leakage; (4) The control method of the fuel cell anode circulation system provided by the present invention defines the control modes when the stack is operating at low, medium and high currents, respectively. The new hydrogen flow distribution is controlled by adding a first proportional valve and a second proportional valve. The inlet pressure can be controlled by adjusting the first proportional valve or the second proportional valve. The circulation flow is controlled by adjusting the speed of the compressor end, thereby covering the requirements of the fuel cell for the anode circulation circuit under all operating conditions and maximizing the use of high-pressure hydrogen energy. The anode circulation system is more flexible in control, and the system operation is stable and robust. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a schematic structural diagram of a fuel cell anode circulation system in an embodiment of the present invention; Figure 2 It is a flow chart of the fuel cell anode circulation system control method in Example 3 of the present invention.

[0020] The markings in the figure are: 1. Hydrogen storage bottle; 2. Pressure reducing valve; 3. Plate heat exchanger; 4. Hydrogen filter; 5. First proportional valve; 6. Second proportional valve; 7. Turbo compressor; 701. Turbine end; 702. Compressor end; 8. Ejector; 801. High-pressure gas inlet; 802. Low-pressure gas inlet; 803. Mixed gas outlet; 9. Water separator; 901. Drain valve; 902. Nitrogen exhaust valve; 10. Fuel cell; 1001. Anode inlet; 1002. Anode outlet; 11. Heat medium outlet pipe; 12. Heat medium inlet pipe; 13. Tail exhaust pipe; 14. Anode inlet pipe. DETAILED DESCRIPTION

[0021] The present invention will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and cannot be used to limit the protection scope of the present invention.

[0022] Example 1

[0023] like Figure 1As shown, this embodiment provides a fuel cell anode circulation system, including a hydrogen storage bottle 1, a hydrogen pretreatment mechanism, a first proportional valve 5, a second proportional valve 6, a turbo compressor 7, an ejector 8, a water separator 9 and a fuel cell stack 10; the hydrogen storage bottle 1 is a high-pressure hydrogen storage bottle, and the turbo compressor 7 includes a turbine end 701 and a pressure end 702 connected to the turbine end 701 through a rotating shaft; the hydrogen storage bottle 1 is connected to a pressure reducing valve 2, the pressure reducing valve 2 is connected to the hydrogen pretreatment mechanism, and the outlet end of the hydrogen pretreatment mechanism is respectively connected to the first proportional valve 5 and the second proportional valve 6; the first proportional valve 5 is connected to the inlet of the turbine end 701, and the outlet of the turbine end 701 is connected to the anode inlet 1001 of the fuel cell stack 10; the second proportional valve 6 is connected to the high-pressure gas inlet 801 of the ejector 8, and the mixed gas outlet 803 of the ejector 8 is connected to the anode inlet 1001; the anode outlet 1002 of the fuel cell stack 10 is connected to the water separator 9, the water separator 9 is connected to the inlet of the pressure end 702, and the outlet of the pressure end 702 is connected to the low-pressure gas inlet 802 of the ejector 8.

[0024] The hydrogen pretreatment mechanism includes a plate heat exchanger 3, which is provided with a refrigerant inlet, a refrigerant outlet, a heat medium inlet and a heat medium outlet; the refrigerant inlet is connected to the pressure reducing valve 2, the heat medium inlet is connected to the coolant outlet of the battery stack 10 through the heat medium inlet pipe 12, and the heat medium outlet is connected to the coolant inlet of the battery stack 10 through the heat medium outlet pipe 11. The high-temperature coolant flowing out of the battery stack 10 preheats the high-pressure hydrogen flowing through the plate heat exchanger 3, which can effectively utilize the waste heat of the cooling system of the battery stack 10 and further improve the energy recovery effect.

[0025] The hydrogen pretreatment mechanism further includes a hydrogen filter 4, the inlet end of the hydrogen filter 4 is connected to the refrigerant outlet, and the outlet end of the hydrogen filter 4 is respectively connected to the inlet ends of the first proportional valve 5 and the second proportional valve 6. The hydrogen filter 4 can filter the high-pressure hydrogen to remove impurities.

[0026] The inlet end of the water separator 9 is connected to the anode outlet 1002 of the fuel cell stack 10, and the gas outlet end of the water separator 9 is connected to the inlet of the compressed gas end 702. The mixed gas and liquid water mixture that have not reacted completely in the fuel cell stack 10 enter the water separator 9 for gas-liquid separation, and the separated circulating hydrogen is output from the gas outlet end of the water separator 9; a drain valve 901 is provided at the liquid outlet end of the water separator 9 for discharging liquid, and a nitrogen exhaust valve 902 is provided on the side or top of the water separator 9, and the outlet ends of the drain valve 901 and the nitrogen exhaust valve 902 are both connected to the tail exhaust pipe 13.

[0027] A first pressure sensor is provided at the anode inlet 1001 of the fuel cell stack 10 , a second pressure sensor is provided at the anode outlet 1002 of the fuel cell stack 10 , and a third pressure sensor is provided at the gas outlet end of the water separator 9 . Each pressure sensor is used to measure the gas pressure at each location.

[0028] The anode inlet 1001 of the fuel cell stack 10 is connected to the anode inlet pipe 14 , and the mixed gas outlet 803 of the ejector 8 and the outlet of the turbine end 701 are both connected to the anode inlet pipe 14 , and communicate with the anode inlet 1001 of the fuel cell stack 10 through the anode inlet pipe 14 .

[0029] Example 2

[0030] This embodiment provides a control method for the anode circulation system of the fuel cell described in Embodiment 1, and the steps are as follows: Step 1: Determine the operating current of the fuel cell stack and the hydrogen inlet pressure and circulation flow requirements.

[0031] Step 2: Switch the working mode according to the working current of the battery stack.

[0032] Mode a: When the stack is in low current operation, the first proportional valve 5 is opened, and the second proportional valve 6 is closed. The stack pressure is controlled by adjusting the first proportional valve 5, and the circulation flow is controlled by adjusting the rotation speed of the compressor end 702.

[0033] Specifically, when the fuel cell stack is in low current operation, the fuel cell stack has low requirements for hydrogen consumption and does not require the participation of the ejector 8. The first proportional valve 5 is opened and the second proportional valve 6 is closed. The new hydrogen in the hydrogen storage bottle 1 enters the turbine end 701 of the turbo compressor 7 after being processed by the hydrogen pretreatment mechanism. The turbine end 701 recovers the pressure potential energy of the high-pressure hydrogen, so that the turbine end 701 drives the compressor end 702 to work. After the mixed gas and liquid water mixture output from the anode outlet 1002 of the fuel cell stack 10 is separated by gas and liquid through the water separator 9, the separated circulating hydrogen is sucked and compressed through the compressor end 702. The compressed circulating hydrogen enters the ejector 8 through the low-pressure gas inlet 802 of the ejector 9, and is output from the mixed gas outlet 803 of the ejector 8, mixed with the new hydrogen output from the turbine end 701 outlet, and enters the fuel cell stack 10 through the anode inlet 1001 of the fuel cell stack 10 to participate in the reaction. At this time, the inlet pressure can be controlled by adjusting the first proportional valve 5, and the circulation flow rate can be controlled by adjusting the rotation speed of the compressor end 702.

[0034] In this mode, all high-pressure hydrogen energy is recovered, effectively reducing the power consumption at the compressor end, and the single-pump operation mode can ensure the stability of the fuel cell stack at low current.

[0035] Mode b: When the stack is in medium current operation, the first proportional valve 5 is fully opened, the second proportional valve 6 is opened, the stack pressure is controlled by adjusting the second proportional valve 6, and the circulation flow is controlled by adjusting the rotation speed of the compressor end 702.

[0036] Specifically, when the fuel cell stack 10 is in medium current operation, the first proportional valve 5 is fully opened, and the second proportional valve 6 is opened. After the new hydrogen in the hydrogen storage bottle 1 is processed by the hydrogen pretreatment mechanism, most of it enters the turbine end 701 of the turbo compressor 7, and a small part enters the ejector 8 through the high-pressure gas inlet 801 of the ejector 8, and is output from the outlet of the turbine end 701 and the mixed gas outlet 803 of the ejector 8, and enters the fuel cell stack 10 through the anode inlet 1001 of the fuel cell stack 10, that is, the new hydrogen flow is provided by the turbine end 701 and the ejector 8; at the same time, the turbine end 701 recovers the new hydrogen energy and drives the compressor end 702 to the fuel cell stack The circulating hydrogen output from the anode outlet 1002 of 10 is sucked and compressed. At this time, the turbine end 701 recovers the most energy. The circulating hydrogen that cannot be supplied through the turbine end 701 is provided by the ejector 8. Due to the inflow of high-pressure hydrogen, the ejector 8 provides auxiliary suction capacity for the circulating hydrogen, so that the compressed circulating hydrogen flows through the ejector 8 and then enters the fuel cell stack 10 through the anode inlet 1002 of the fuel cell stack 10 to participate in the reaction, that is, the compressor end 702 and the ejector 8 are connected in series to jointly provide the anode circulation capacity; at this time, the inlet pressure is controlled by adjusting the second proportional valve 6, and the circulation flow rate is controlled by adjusting the rotation speed of the compressor end 702.

[0037] Mode c: When the stack is in high current operation, the first proportional valve 5 is opened, the second proportional valve 6 is fully opened, the stack pressure is controlled by adjusting the first proportional valve 5, and the circulation flow is controlled by adjusting the rotation speed of the compressor end 702.

[0038] Specifically, when the fuel cell stack is in high current operation, in order to meet the extreme demand of the anode circulation, the first proportional valve 5 is opened, and the second proportional valve 6 is fully opened. After the new hydrogen in the hydrogen storage bottle 1 is processed by the hydrogen pretreatment mechanism, most of it enters the ejector 8 through the high-pressure gas inlet 801 of the ejector 8, and a small part enters the turbine end 701 of the turbo compressor 7, and is output from the outlet of the turbine end 701 and the mixed gas outlet 803 of the ejector 8, and enters the fuel cell stack through the anode inlet 1001 of the fuel cell stack 10, that is, the new hydrogen flow is provided by the ejector 8 and the turbine end 701; at the same time, due to the inflow of high-pressure hydrogen, the ejector 8 has a positive impact on the anode outlet of the fuel cell stack 10. The circulating hydrogen output by 1002 provides the main suction capacity. At this time, the suction capacity of the ejector 8 is the largest, and the ejector 8 is used to maximize the suction and circulation of the high-pressure hydrogen. The turbine end 701 provides the remaining circulating hydrogen demand, and the circulating hydrogen is auxiliary sucked and compressed by recovering the new hydrogen energy and driving the compressor end 702. After the compressed circulating hydrogen flows through the ejector 8, it enters the fuel cell stack 10 through the anode inlet 1001 of the fuel cell stack 10 to participate in the reaction, that is, the ejector 8 and the compressor end 702 jointly provide the anode circulation capacity; at this time, the inlet pressure is controlled by adjusting the first proportional valve 5, and the circulation flow is controlled by adjusting the rotation speed of the compressor end 702.

[0039] Example 3

[0040] The three working modes provided by the control method of the fuel cell anode circulation system in Example 2 can cover the requirements of the fuel cell, especially the full power stage of the high-power fuel cell, for hydrogen supply and anode circulation.

[0041] For the variable load condition of the fuel cell stack, that is, the stack current is low→medium→high when the load is increased, and the stack current is high→medium→low when the load is decreased, the inlet pressure is controlled by controlling the first proportional valve and the second proportional valve, and a gradual transition can be achieved, and there is no sudden change from full open to full closed during the change of operating conditions; the circulation flow is controlled by the compression end of the turbo compressor, which can ensure smooth switching of operating conditions, avoid unstable control targets due to improper control, greatly improve the control effect, and improve the stability of system operation.

[0042] In this embodiment, for a conventional fuel cell power request, a control method for a fuel cell anode circulation system when a stack is loaded is provided, and the steps are as follows: Step 1: Determine the operating current of the fuel cell stack and the hydrogen inlet pressure and circulation flow requirements.

[0043] Step 2, enter the low current operation mode of the fuel cell stack (ie, mode a), open the first proportional valve 5, close the second proportional valve 6, control the stack pressure by adjusting the first proportional valve 5, and control the circulation flow by adjusting the speed of the compressor end 702.

[0044] Step 3: Determine whether the stack pressure and circulation flow meet the requirements. If so, continue to determine whether the stack voltage and single chip consistency meet the required indicators. If so, end the control. If the stack pressure and circulation flow do not meet the requirements or the stack voltage and single chip consistency do not meet the required indicators, proceed to step 4.

[0045] Step 4, enter the current operation mode in the fuel cell stack (i.e., mode b), fully open the first proportional valve 5, open the second proportional valve 6, control the stack pressure by adjusting the second proportional valve 6, and control the circulation flow by adjusting the speed of the compressor end 702.

[0046] Step 5: Determine whether the stack pressure and circulation flow meet the requirements. If so, continue to determine whether the stack voltage and single chip consistency meet the required indicators. If so, end the control. If the stack pressure and circulation flow do not meet the requirements or the stack voltage and single chip consistency do not meet the required indicators, proceed to step 6.

[0047] Step 6, enter the high current operation mode of the battery stack (ie, mode c), open the first proportional valve 5, fully open the second proportional valve 6, control the stack pressure by adjusting the first proportional valve 5, and control the circulation flow by adjusting the speed of the compressor end 702.

[0048] Step 7: Determine whether the stack pressure and circulation flow meet the requirements. If so, continue to determine whether the stack voltage and single chip consistency meet the required indicators. If so, end the control. If the stack pressure and circulation flow do not meet the requirements or the stack voltage and single chip consistency do not meet the required indicators, proceed to step 8.

[0049] Step 8: Because the maximum capacity cannot meet the anode supply or reflux demand, the machine is shut down due to a fault and the control is ended.

[0050] In this embodiment, the hydrogen inlet pressure P_stkin is obtained by a first pressure sensor provided at the anode inlet 1001 of the fuel cell stack 10 .

[0051] In this embodiment, the inlet pressure P_stkout of the water separator 9 is obtained by the second pressure sensor provided at the anode outlet 1002 of the stack 10, and the outlet pressure P_sepout of the water separator 9 is obtained by the third pressure sensor provided at the outlet of the water separator 9. Then the flow resistance dP_sep of the water separator is P_stkout-Psepout, and the circulation flow rate of hydrogen M_recir is F(dP_sep, I0), where I0 is the stack current. Since the gas components of the stack are different under different stack currents, the flow resistance characteristics of the water separator need to consider the working conditions under different currents. For the known relationship of the test, the circulation flow rate can be obtained by two-dimensional table lookup.

[0052] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present application may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program codes.

[0053] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0054] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0055] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0056] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A fuel cell anode circulation system, characterized in that: It includes a hydrogen storage bottle, a hydrogen pretreatment mechanism, a first proportional valve, a second proportional valve, a turbo compressor, an ejector and a fuel cell stack, wherein the turbo compressor includes a turbine end and a compressor end connected to the turbine end; The hydrogen storage bottle is connected to a hydrogen pretreatment mechanism, and an outlet end of the hydrogen pretreatment mechanism is respectively connected to a first proportional valve and a second proportional valve; The first proportional valve is connected to the turbine end inlet, and the turbine end outlet is connected to the anode inlet of the fuel cell stack; The second proportional valve is connected to the high-pressure gas inlet of the ejector, and the mixed gas outlet of the ejector is connected to the anode inlet; The anode outlet of the fuel cell stack is connected to the compressed gas inlet, and the compressed gas outlet is connected to the low-pressure gas inlet of the ejector.

2. The fuel cell anode circulation system according to claim 1, characterized in that: A pressure reducing valve is connected between the hydrogen storage bottle and the hydrogen pretreatment mechanism.

3. The fuel cell anode circulation system according to claim 2, characterized in that: The hydrogen pretreatment mechanism comprises a plate heat exchanger, and the plate heat exchanger is provided with a refrigerant inlet, a refrigerant outlet, a heat medium inlet and a heat medium outlet; The refrigerant inlet is connected to the pressure reducing valve, the heat medium inlet is connected to the coolant outlet of the fuel cell stack through a heat medium inlet pipe, and the heat medium outlet is connected to the coolant inlet of the fuel cell stack through a heat medium outlet pipe.

4. The fuel cell anode circulation system according to claim 3, characterized in that: The hydrogen pretreatment mechanism further includes a hydrogen filter, the inlet end of the hydrogen filter is connected to the refrigerant outlet, and the outlet end of the hydrogen filter is respectively connected to the inlet ends of the first proportional valve and the second proportional valve.

5. The fuel cell anode circulation system according to claim 1, characterized in that: It also includes a water separator, the inlet end of the water separator is connected to the anode outlet of the fuel cell stack, and the gas outlet end of the water separator is connected to the compressed gas inlet; the liquid outlet end of the water separator is provided with a drain valve, and the side or top of the water separator is provided with a nitrogen exhaust valve, and the outlet ends of the drain valve and the nitrogen exhaust valve are both connected to the tail drain pipe.

6. The fuel cell anode circulation system according to claim 5, characterized in that: A first pressure sensor is provided at the anode inlet of the fuel cell stack, a second pressure sensor is provided at the anode outlet of the fuel cell stack, and a third pressure sensor is provided at the gas outlet end of the water separator.

7. A method for controlling a fuel cell anode circulation system according to any one of claims 1 to 6, characterized in that: include: Determine the operating current of the fuel cell stack and the hydrogen inlet pressure and circulation flow requirements; When the stack is in low current operation, the first proportional valve is opened and the second proportional valve is closed. The stack pressure is controlled by adjusting the first proportional valve, and the circulation flow is controlled by adjusting the speed of the compressor end. When the stack is in medium current operation, the first proportional valve is fully opened, the second proportional valve is opened, the stack inlet pressure is controlled by adjusting the second proportional valve, and the circulation flow is controlled by adjusting the speed of the compressor end; When the fuel cell stack is running at high current, the first proportional valve is opened and the second proportional valve is fully opened. The pressure entering the stack is controlled by adjusting the first proportional valve, and the circulation flow is controlled by adjusting the speed of the compressor end.

8. The control method of the fuel cell anode circulation system according to claim 7, characterized in that: When the fuel cell stack is in low current operation, the new hydrogen in the hydrogen storage bottle enters the turbine end of the turbo compressor after being processed by the hydrogen pretreatment mechanism, so that the turbine end drives the compressor end to suck and compress the circulating hydrogen output from the anode outlet of the fuel cell stack. After the compressed circulating hydrogen flows through the ejector, it is mixed with the new hydrogen output from the turbine end outlet and enters the fuel cell stack through the anode inlet of the fuel cell stack to participate in the reaction. When the fuel cell stack is in medium current operation, the new hydrogen in the hydrogen storage bottle is processed by the hydrogen pretreatment mechanism, and most of it enters the turbine end of the turbo compressor, and a small part enters the ejector through the high-pressure gas inlet of the ejector, and is output from the outlet of the turbine end and the mixed gas outlet of the ejector, and enters the fuel cell stack through the anode inlet of the fuel cell stack; at the same time, the turbine end recovers the energy of the new hydrogen and drives the compressor end to suck and compress the circulating hydrogen output from the anode outlet of the fuel cell stack. Due to the influx of high-pressure hydrogen, the ejector provides auxiliary suction capacity for the circulating hydrogen, so that the compressed circulating hydrogen flows through the ejector and enters the fuel cell stack through the anode inlet of the fuel cell stack to participate in the reaction; When the fuel cell stack is operating at high current, the new hydrogen in the hydrogen storage bottle is processed by the hydrogen pretreatment mechanism, and most of it enters the ejector through the high-pressure gas inlet of the ejector, and a small part enters the turbine end of the turbo compressor, and is output from the outlet of the turbine end and the mixed gas outlet of the ejector, and enters the fuel cell stack through the anode inlet of the fuel cell stack; at the same time, due to the influx of high-pressure hydrogen, the ejector provides the main suction capacity for the circulating hydrogen output from the anode outlet of the fuel cell stack, the turbine end recovers the energy of the new hydrogen and drives the compressor end to assist in the suction and compression of the circulating hydrogen, and the compressed circulating hydrogen flows through the ejector, and enters the fuel cell stack through the anode inlet of the fuel cell stack to participate in the reaction.

9. The control method of the fuel cell anode circulation system according to claim 7, characterized in that: When the fuel cell stack is loaded, the control method includes: Determine the operating current of the fuel cell stack and the hydrogen inlet pressure and circulation flow requirements; Enter the low current operation mode of the fuel cell stack, open the first proportional valve, close the second proportional valve, control the stack pressure by adjusting the first proportional valve, and control the circulation flow by adjusting the speed of the compressor end; Determine whether the stack pressure and circulation flow meet the requirements. If so, continue to determine whether the stack voltage and single chip consistency meet the required indicators. If so, end the control; If the stack pressure and circulation flow rate do not meet the requirements or the stack voltage and single chip consistency do not meet the required indicators, the stack current operation mode is entered, the first proportional valve is fully opened, the second proportional valve is opened, the stack pressure is controlled by adjusting the second proportional valve, and the circulation flow rate is controlled by adjusting the speed of the compressor end; Determine whether the stack pressure and circulation flow meet the requirements. If so, continue to determine whether the stack voltage and single chip consistency meet the required indicators. If so, end the control; If the stack pressure and circulation flow rate do not meet the requirements or the stack voltage and single chip consistency do not meet the required indicators, the stack high current operation mode is entered, the first proportional valve is opened, the second proportional valve is fully opened, the stack pressure is controlled by adjusting the first proportional valve, and the circulation flow rate is controlled by adjusting the speed of the compressor end; Determine whether the stack pressure and circulation flow meet the requirements. If so, continue to determine whether the stack voltage and single chip consistency meet the required indicators. If so, end the control; If the stack pressure and circulation flow do not meet the requirements or the stack voltage and single chip consistency do not meet the required indicators, the fault will be shut down and the control will end.

10. The control method of the fuel cell anode circulation system according to claim 7, characterized in that: The hydrogen inlet pressure P_stkin is obtained by a first pressure sensor provided at the anode inlet of the fuel cell stack; The inlet pressure P_stkout of the water separator is obtained by a second pressure sensor provided at the anode outlet of the fuel cell stack, and the outlet pressure P_sepout of the water separator is obtained by a third pressure sensor provided at the gas outlet of the water separator. Then, the flow resistance dP_sep of the water separator is P_stkout-Psepout, and the circulating flow rate of hydrogen is M_recir=F(dP_sep,I0), wherein I0 is the fuel cell stack current.

Images