CN113675446A - Fuel cell voltage control system and control method - Google Patents
Fuel cell voltage control system and control method Download PDFInfo
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- CN113675446A CN113675446A CN202111061415.6A CN202111061415A CN113675446A CN 113675446 A CN113675446 A CN 113675446A CN 202111061415 A CN202111061415 A CN 202111061415A CN 113675446 A CN113675446 A CN 113675446A
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- Prior art keywords
- fuel cell
- cell voltage
- inlet
- control system
- stack
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M8/00—Fuel cells; Manufacture thereof
- H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
- H01M8/04298—Processes for controlling fuel cells or fuel cell systems
- H01M8/04313—Processes for controlling fuel cells or fuel cell systems characterised by the detection or assessment of variables; characterised by the detection or assessment of failure or abnormal function
- H01M8/04537—Electric variables
- H01M8/04544—Voltage
- H01M8/04559—Voltage of fuel cell stacks
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/30—Hydrogen technology
- Y02E60/50—Fuel cells
Abstract
The invention relates to the technical field of fuel cells, in particular to a fuel cell voltage control system and a control method, wherein the fuel cell comprises a hydrogen source and an electric pile, the electric pile comprises a gas inlet and a waste gas outlet, and the gas inlet is communicated with an air inlet pipe; the fuel cell voltage control system comprises a catalytic combustor, the hydrogen source and the waste gas outlet are communicated with the inlet of the catalytic combustor, and the outlet of the catalytic combustor is communicated with an air inlet pipe; according to the invention, the catalytic combustor can reduce the oxygen content of the gas entering the stack as required, so that the voltage of the fuel cell stack can be effectively controlled, and the damage of high potential to the catalyst of the stack is avoided; the stack air is maintained at low oxygen concentration, high humidity and reasonable flow level under low current, and the stable operation of the fuel cell under the condition of low power output is facilitated; the fuel cell can be maintained at a lower net output level for a long time, and the requirement of external electric load is met.
Description
Technical Field
The invention relates to the technical field of fuel cells, in particular to a fuel cell voltage control system and a control method.
Background
In a power system including a fuel cell, there are cases where the demand for short or long-term electrical loads is extremely small due to the energy matching of the power system as a whole and the load dynamic change. In such a case, the fuel cell system would be required to maintain a zero net output power level, the fuel cell system efficiency is in a high range, and smooth operation can be maintained.
If the external electrical load is frequently switched between the zero state and the normal state, the fuel cell system is also subjected to shutdown and startup operation, which causes the frequent startup and shutdown of the fuel cell, thereby causing the fuel cell to cycle between the open-circuit voltage and the normal operating voltage, aggravating the degradation of the fuel cell catalyst, and causing the output performance and the durability of the fuel cell system to be reduced. It is therefore desirable that the fuel cell system be maintained in continuous operation without shutdown when the electrical load requirements are minimal, in which case the fuel cell voltage needs to be maintained within a suitable range and the energy consumption and output power of the fuel cell system are also maintained at extremely low levels.
In the prior art, for example, patent No. CN 105609837B discloses a power supply system and a voltage control method of a fuel cell, the voltage control method of the fuel cell includes: in a low load state, cutting off the electrical connection of the fuel cell to the load; supplying oxygen to the fuel cell under a preset condition during a period when the electrical connection is disconnected; detecting an open circuit voltage of the fuel cell after supplying oxygen to the fuel cell under the predetermined condition; reducing an amount of oxygen supplied to the fuel cell when the open circuit voltage is higher than a target voltage by a first value or more; increasing an amount of oxygen supplied to the fuel cell when the open circuit voltage is lower than the target voltage by a second value or more; and maintaining the amount of oxygen supplied to the fuel cell when the open-circuit voltage is smaller than the sum of the target voltage and the first value and larger than a value obtained by subtracting the second value from the target voltage.
However, this solution has some drawbacks:
1. it is difficult for the fuel cell system to maintain the output voltage in a reasonable range while in an operating state of low current and low output power.
2. Maintaining the fuel cell at a low output for a long time may cause severe damage to the catalyst, reducing the life of the fuel cell.
3. It is currently difficult to control the voltage of the fuel cell within a reasonable range while maintaining a low power output state of the fuel cell.
Disclosure of Invention
The technical problem to be solved by the invention is as follows: the fuel cell voltage control system and the control method solve the problems that the current fuel cell can not maintain an extremely low power operation state under the condition of low external electric load, the output voltage of a galvanic pile is difficult to control in a required reasonable range under the condition, and the damage to a membrane electrode of the fuel cell is large.
In order to solve the technical problems, the invention adopts the technical scheme that:
a fuel cell voltage control system comprises a hydrogen source and a galvanic pile, wherein the galvanic pile comprises a gas inlet and a waste gas outlet, and the gas inlet is communicated with an air inlet pipe; the fuel cell voltage control system comprises a catalytic combustor, the hydrogen source and the waste gas outlet are communicated with the inlet of the catalytic combustor, and the outlet of the catalytic combustor is communicated with an air inlet pipe.
Preferably, the fuel cell voltage control system further includes a control unit, a cathode off-gas circulation flow control valve and a hydrogen flow control valve, the cathode off-gas circulation flow control valve being connected between the off-gas outlet and the inlet of the catalytic combustor;
the hydrogen flow control valve is connected between the hydrogen source and the inlet of the catalytic burner;
the control unit is electrically connected with the cathode waste gas circulating flow control valve and the hydrogen flow control valve.
Preferably, a pressure regulating valve is further arranged between the cathode waste gas circulation flow control valve and the waste gas outlet.
Preferably, an oxygen concentration sensor and a flow meter are sequentially arranged between the communication position of the outlet of the catalytic combustor and the air inlet pipe and the gas inlet of the galvanic pile, and the concentration sensor and the flow meter are respectively and electrically connected with the control unit.
Preferably, an air compressor is further arranged between the flow meter and the gas inlet of the galvanic pile, and the air compressor is electrically connected with the control unit.
Preferably, an intercooler is further arranged between the air compressor and the gas inlet of the electric pile; the air intake tube has an air intake end with an air filter thereon.
Preferably, the electric pile is provided with a battery voltage monitoring module, and the battery voltage monitoring module is electrically connected with the control unit.
In order to solve the technical problem, the invention adopts another technical scheme as follows:
the control method of the fuel cell voltage control system comprises
Judging whether the output voltage of the electric pile is in a target value range or not;
if not, controlling the hydrogen and the cathode waste gas at the waste gas outlet of the galvanic pile to enter a catalytic combustor to generate mixed gas for changing the oxygen concentration and enter the galvanic pile;
and adjusting the oxygen concentration and the gas inlet flow rate corresponding to the stack output target voltage under the target current of the fuel cell, and then judging whether the stack output voltage reaches the target value range again.
Preferably, the battery voltage monitoring module acquires the output voltage of the electric pile;
the control unit judges whether the output voltage of the electric pile is in a target value range;
if not, controlling the opening degrees of the cathode waste gas circulation flow control valve and the hydrogen flow control valve of the control unit to control hydrogen and cathode waste gas at the waste gas outlet of the galvanic pile to enter a catalytic burner to generate mixed gas for changing the oxygen concentration, and then entering the galvanic pile through an air compressor;
and adjusting the oxygen concentration and the gas inlet flow rate corresponding to the stack output target voltage under the target current of the fuel cell, and then judging whether the stack output voltage reaches the target value range again.
Preferably, the adjusting of the oxygen concentration and the gas inlet flow rate comprises:
the control unit monitors the oxygen concentration and flow at the inlet of the air compressor through an oxygen concentration sensor and a flowmeter, and makes the oxygen concentration and flow at the inlet of the air compressor reach the oxygen concentration and gas inlet flow corresponding to the target voltage output by the electric pile when the fuel cell operates at the target current by adjusting the cathode waste gas circulation flow control valve and the hydrogen flow control valve.
The invention has the beneficial effects that: the catalytic combustor can adjust (reduce) the oxygen content of the stack-entering gas as required, so as to effectively control the voltage of the fuel cell stack and avoid the damage of high potential to the stack catalyst; the stack air is maintained at low oxygen concentration, high humidity and reasonable flow level under low current, and the stable operation of the fuel cell under the condition of low power output is facilitated; the fuel cell can be maintained at a lower net output level for a long time, and the requirement of external electric load is met.
Drawings
Fig. 1 is a block diagram of a fuel cell voltage control system according to a first embodiment of the present invention;
fig. 2 is a schematic flow chart of a control method of a fuel cell voltage control system according to a second embodiment of the present invention;
description of reference numerals: 1. a galvanic pile; 2. an air filter; 3. an oxygen concentration sensor; 4. a flow meter; 5. an air compressor; 6. an intercooler; 7. a pressure regulating valve; 8. a cathode exhaust gas circulation flow control valve; 9. a battery voltage monitoring module; 10. a catalytic combustor; 11. a hydrogen flow rate control valve; 12. a control unit.
Detailed Description
In order to explain technical contents, achieved objects, and effects of the present invention in detail, the following description is made with reference to the accompanying drawings in combination with the embodiments.
Example one
Referring to fig. 1, a voltage control system for a fuel cell includes a hydrogen source and a stack 1, where the stack 1 includes a gas inlet and a waste gas outlet, and the gas inlet is communicated with an air inlet pipe; the fuel cell voltage control system comprises a catalytic combustor 10, the hydrogen source and the waste gas outlet are communicated with the inlet of the catalytic combustor 10, and the outlet of the catalytic combustor 10 is communicated with an air inlet pipe.
The fuel cell voltage control system further includes a control unit 12, a cathode off-gas circulation flow control valve 8, and a hydrogen flow control valve 11, the cathode off-gas circulation flow control valve 8 being connected between an off-gas outlet and an inlet of the catalytic combustor 10;
the hydrogen flow control valve 11 is connected between the hydrogen source and the inlet of the catalytic burner 10;
the control unit 12 is electrically connected to the cathode off-gas circulation flow control valve 8 and the hydrogen flow control valve 11.
And a pressure regulating valve 7 is also arranged between the cathode waste gas circulation flow control valve 8 and the waste gas outlet.
An oxygen concentration sensor 3 and a flow meter 4 are sequentially arranged between the communication position of the outlet of the catalytic combustor 10 and the air inlet pipe and the gas inlet of the galvanic pile 1, and the concentration sensor and the flow meter 4 are respectively and electrically connected with a control unit 12.
An air compressor 5 is further arranged between the flow meter 4 and the gas inlet of the electric pile 1, and the air compressor 5 is electrically connected with the control unit 12.
An intercooler 6 is also arranged between the air compressor 5 and the gas inlet of the electric pile 1; the air intake pipe has an air intake end with an air filter 2 thereon.
The electric pile 1 is provided with a battery voltage monitoring module 9, and the battery voltage monitoring module 9 is electrically connected with a control unit 12.
Example two
Referring to fig. 2, a control method of a fuel cell voltage control system according to an embodiment includes S110, after receiving a command from a controller to enter a low power output state, a fuel cell system starts to detect a voltage of a fuel cell (stack 1), and determines whether the voltage of the fuel cell is smaller than a target value V1, if so, the control method continues to S110;
s120, if the output voltage of the fuel cell is higher than the target value (if not), starting voltage control; opening a cathode waste gas circulation flow control valve 8 and a hydrogen flow control valve 11 to enable a certain amount of cathode waste gas and hydrogen to enter a catalytic combustion device, and after the cathode waste gas and the hydrogen are mixed and react in the catalytic combustion device, forming mixed gas with lower oxygen concentration and introducing the mixed gas into an inlet of an air compressor 5;
s130, the fuel cell operates under a target current, and the oxygen concentration and the inlet flow of the air compressor 5 corresponding to the target voltage output by the fuel cell under the current are obtained; the control unit 12 monitors the oxygen concentration and flow rate at the inlet of the air compressor 5 through the oxygen concentration sensor 3 and the air compressor 5 inlet flow meter 4, and then adjusts the cathode off-gas circulation flow control valve 8 and the hydrogen flow control valve 11 so that the oxygen concentration and flow rate at the inlet of the air compressor 5 reach target values;
and S140, if the voltage of the fuel cell (the electric pile 1) is smaller than the target value V1, ending, otherwise, returning to S120.
And circulating through the steps to enable the output voltage of the fuel cell to finally reach the required target range value.
The above description is only an embodiment of the present invention, and not intended to limit the scope of the present invention, and all equivalent changes made by using the contents of the present specification and the drawings, or applied directly or indirectly to the related technical fields, are included in the scope of the present invention.
Claims (10)
1. A fuel cell voltage control system comprises a hydrogen source and a galvanic pile, wherein the galvanic pile comprises a gas inlet and a waste gas outlet, and the gas inlet is communicated with an air inlet pipe; the fuel cell voltage control system is characterized by comprising a catalytic combustor, wherein the hydrogen source and the waste gas outlet are communicated with an inlet of the catalytic combustor, and an outlet of the catalytic combustor is communicated with an air inlet pipe.
2. The fuel cell voltage control system according to claim 1, further comprising a control unit, a cathode off-gas circulation flow control valve, and a hydrogen flow control valve, the cathode off-gas circulation flow control valve being connected between an off-gas outlet and an inlet of a catalytic combustor;
the hydrogen flow control valve is connected between the hydrogen source and the inlet of the catalytic burner;
the control unit is electrically connected with the cathode waste gas circulating flow control valve and the hydrogen flow control valve.
3. The fuel cell voltage control system according to claim 2, wherein a pressure regulating valve is further provided between the cathode off-gas circulation flow rate control valve and the off-gas outlet.
4. The fuel cell voltage control system according to claim 2, wherein an oxygen concentration sensor and a flow meter are sequentially provided between a communication point between the outlet of the catalytic combustor and the air inlet pipe and the gas inlet of the stack, and the concentration sensor and the flow meter are respectively electrically connected to the control unit.
5. The fuel cell voltage control system of claim 4, wherein an air compressor is further disposed between the flow meter and the stack gas inlet, and the air compressor is electrically connected to the control unit.
6. The fuel cell voltage control system of claim 5, wherein an intercooler is further provided between the air compressor and the stack gas inlet; the air intake tube has an air intake end with an air filter thereon.
7. The fuel cell voltage control system according to claim 2, wherein the stack is provided with a cell voltage monitoring module, and the cell voltage monitoring module is electrically connected with a control unit.
8. A control method of the fuel cell voltage control system according to any one of claims 1 to 7, characterized by comprising
Judging whether the output voltage of the electric pile is in a target value range or not;
if not, controlling the hydrogen and the cathode waste gas at the waste gas outlet of the galvanic pile to enter a catalytic combustor to generate mixed gas for changing the oxygen concentration and enter the galvanic pile;
and adjusting the oxygen concentration and the gas inlet flow rate corresponding to the stack output target voltage under the target current of the fuel cell, and then judging whether the stack output voltage reaches the target value range again.
9. The control method of the fuel cell voltage control system according to claim 8, characterized in that a stack output voltage is acquired by the cell voltage monitoring module;
the control unit judges whether the output voltage of the electric pile is in a target value range;
if not, controlling the opening degrees of the cathode waste gas circulation flow control valve and the hydrogen flow control valve of the control unit to control hydrogen and cathode waste gas at the waste gas outlet of the galvanic pile to enter a catalytic burner to generate mixed gas for changing the oxygen concentration, and then entering the galvanic pile through an air compressor;
and adjusting the oxygen concentration and the gas inlet flow rate corresponding to the stack output target voltage under the target current of the fuel cell, and then judging whether the stack output voltage reaches the target value range again.
10. The control method of the fuel cell voltage control system according to claim 8, wherein the adjusting of the oxygen concentration and the gas inlet flow rate includes:
the control unit monitors the oxygen concentration and flow at the inlet of the air compressor through an oxygen concentration sensor and a flowmeter, and makes the oxygen concentration and flow at the inlet of the air compressor reach the oxygen concentration and gas inlet flow corresponding to the target voltage output by the electric pile when the fuel cell operates at the target current by adjusting the cathode waste gas circulation flow control valve and the hydrogen flow control valve.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111061415.6A CN113675446A (en) | 2021-09-10 | 2021-09-10 | Fuel cell voltage control system and control method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111061415.6A CN113675446A (en) | 2021-09-10 | 2021-09-10 | Fuel cell voltage control system and control method |
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| Publication Number | Publication Date |
|---|---|
| CN113675446A true CN113675446A (en) | 2021-11-19 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202111061415.6A Pending CN113675446A (en) | 2021-09-10 | 2021-09-10 | Fuel cell voltage control system and control method |
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| CN (1) | CN113675446A (en) |
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2021
- 2021-09-10 CN CN202111061415.6A patent/CN113675446A/en active Pending
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