JP3433959B2 - Operation and control method of fuel cell - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for operating and controlling a fuel cell. 2. Description of the Related Art FIG. 2 shows a conventional method of operating and controlling a fuel cell.
This will be described below with reference to FIG. The fuel cell 1 has, for example, a structure in which an electrolyte (both not shown) is interposed between an anode and a cathode. The inverter device 2 is connected to the fuel cell 1 and outputs desired electricity to an external load. The fuel supply system 3 is connected to the anode of the fuel cell 1. The oxidant supply system 4 is connected to the cathode of the fuel cell 1. Two flow meters 5a, 5b
Is a pipe between the fuel supply system 3 and the fuel cell 1,
It is interposed in the pipe between the oxidant supply system 4 and the fuel cell 1, respectively. An external load signal and signals based on the supply amounts of fuel and oxidant from the flow meters 5a and 5b are input to the control unit 6, respectively. A predetermined control signal is output from the control unit 6 to the fuel supply system 3, the oxidant supply system 4, and the inverter device 2, respectively. In the fuel cell power generation system having the structure shown in FIG. 2, when the amount of electricity consumed by the external load increases, the information is transmitted as an external load signal through the control unit 6 to the fuel supply system 3, The output is output to the oxidizing agent supply system 4 and the inverter device 2 respectively, and the voltage drop caused by the increase of the fuel, the oxidizing agent and the electric output of the fuel cell 1 corresponding to the increase of the electric consumption is corrected. It is controlled to obtain. On the other hand, when the amount of electricity consumed by the external load decreases, the information is output as an external load signal to the fuel supply system 3, the oxidant supply system 4, and the inverter device 2 through the control device unit 6, respectively. Control is performed so as to compensate for a decrease in fuel and oxidant corresponding to the amount of decrease in electric consumption and an increase in voltage due to a decrease in electric output of the fuel cell 1, and to obtain a rated AC output. [0005] FIG. 3 shows general electric output characteristics of a fuel cell. When the supply pressure of the fuel or the oxidant is constant, as shown in FIG. 3, as the electric output of the fuel cell increases, the consumption of the fuel and the oxidant in the fuel cell increases, and the output voltage decreases. . As a result, in order to obtain a rated AC output, it is necessary to boost the voltage by the inverter device. However, the fuel cell output voltage and the fuel cell electric output can be increased by increasing the supply pressure of the fuel or the oxidant supplied to the fuel cell. [0006] The above-mentioned conventional method for operating and controlling a fuel cell is characterized in that the fuel or oxidant supply pressure is kept constant, and the fuel and oxidant increase and decrease corresponding to the amount of increase or decrease in electricity consumption. Since the voltage drop and the rise due to the increase in the electric output of the fuel cell are corrected, there are the following problems. (1) When the electric output of the fuel cell 1 is increased in response to the increase of the external load, the output voltage of the fuel cell is greatly reduced as shown in FIG. (2) Fuel for increasing electric output,
Even if an attempt is made to increase the supply amount of the oxidizing agent, the fuel supply system 3 and the oxidizing agent supply system 4 have very poor follow-up performance, so that the fuel cell power generation system cannot follow an increase in the external load with a fast response. . (3) When the electric output of the fuel cell 1 is reduced in response to the decrease in the external load, the output voltage of the fuel cell increases greatly as shown in FIG. (4) It is necessary to design an inverter device in consideration of the output voltage width when the fuel cell output decreases and increases as in (1) and (3). SUMMARY OF THE INVENTION An object of the present invention is to provide a fuel cell operation / control method capable of improving the load following capability of a fuel cell when an external load increases and simplifying the design of an inverter device. It is. [0009] The present invention provides an anode electrode,
Cathode pole and solid fraction interposed between these electrodes
A fuel cell provided with a secondary electrolyte;
Fuel supply system for supply and oxidation to the cathode
An oxidizing agent supply system for supplying an oxidizing agent;
At least one of the residual fuel discharge pipe and the residual oxidant discharge pipe
Pressure control valve interposed in the
Fuel provided with an inverter device connected to the electric output side
Those who operate and control the fuel cell using the battery power generation system
The fuel supply system when the external load increases.
Supply of fuel and oxidizers from feed and oxidizer supply systems
With the flow rate constant, lower the opening of the pressure control valve.
To supply at least one of the fuel and the oxidizer.
Increase the supply pressure, increase the output voltage under a constant current, and
When increasing the electrical output of the fuel cell and reducing the external load
The fuel from the fuel supply system and the oxidant supply system
With the supply flow rate of the oxidant and the
Increase the opening of the roll valve to increase the fuel and oxidizer
Reduce the supply pressure of at least one, and under a constant current
Reduce the output voltage to reduce the electrical output of the fuel cell,
An operation and control method of a fuel cell characterized by following a load . According to the present invention, the anode, the cathode and the
And a solid polymer electrolyte interposed between these electrodes.
Fuel cell, and a fuel cell for supplying fuel to the anode.
A fuel supply system and an oxidizer for supplying an oxidant to the cathode.
Oxidant supply system and remaining fuel discharge pipe of the fuel cell
And at least one of the remaining oxidant discharge pipes
A pressure control valve is connected to the electric output side of the fuel cell.
Fuel cell power generation system provided with a connected inverter device
This is a method for operating and controlling the fuel cell by the system. this
External load increases in such fuel cell power generation systems
When the fuel supply system and the oxidant supply system
At a constant supply flow rate of the fuel and the oxidant, the pressure
Lower the opening of the control valve to reduce the fuel and oxidizer
By increasing the supply pressure of at least one of
Therefore, based on the relationship shown in FIG.
It is possible to increase the electric output of the fuel cell by increasing the voltage.
Wear. On the other hand, when the external load decreases, the fuel supply system
Supply of fuel and oxidizers from feed and oxidizer supply systems
When the flow rate is constant, open the pressure control valve
To supply at least one of the fuel and the oxidizer.
By lowering the supply pressure, as shown in FIG.
The output voltage is lowered at a constant current from the
The air output can be reduced. Therefore, the supply pressure of the fuel or the oxidant to the fuel cell can be instantaneously increased in response to the increase in the external load, so that a high external load followability that instantaneously increases the electric output of the fuel cell can be exhibited . [0011] Further, a decrease in the output voltage due to an increase in the electric output of the fuel cell, or an increase in the output voltage due to a decrease in the electric output of the fuel cell are also caused by at least one of the fuel and the oxidant supplied to the fuel cell as described above. By raising and lowering the supply pressure of the fuel cell, it is possible to reduce the variation width of the fuel cell output voltage. An embodiment of the present invention will be described below in detail with reference to FIG. FIG. 1 is a schematic diagram showing a fuel cell power generation system. The fuel cell 11 has, for example, a structure in which a solid polymer electrolyte (both not shown) is interposed between an anode and a cathode. The inverter device 12 is connected to the fuel cell 11 and outputs desired electricity to an external load. The fuel supply system 13 is connected to the anode of the fuel cell 11. The oxidant supply system 14 is connected to the cathode of the fuel cell 1. The two flow meters 15a and 15b are interposed in a pipe between the fuel supply system 13 and the fuel cell 11 and a pipe between the oxidant supply system 14 and the fuel cell 11, respectively. 2
The two pressure gauges 16a, 16b are connected to the flow meter 1 of the pipe.
5a, the fuel supply pressure on the upstream side,
5b are respectively arranged for measuring the oxidant supply pressure upstream of the oxidant supply 5b. Two pressure control valves 17a, 17b
Is provided downstream of the fuel cell (remaining fuel discharge pipe and residual oxidant discharge pipe), and the fuel supplied to the fuel cell 11 by adjusting the opening of each of the control valves 17a and 17b. And the supply pressure of the oxidizing agent can be controlled. The controller unit 18 includes an external load signal, a signal based on the supply amounts of fuel and oxidant from the flow meters 15a and 15b, and the pressure gauge 1
6 and a signal based on the supply pressure of the fuel and the oxidant. A predetermined control signal is output from the control unit 18 to the fuel supply system 3, the oxidant supply system 4, and the inverter device 12, respectively, and the opening degree of each of the pressure control valves 17a, 17b is adjusted. Is output. In such a fuel cell power generation system, when an external signal is input to the control unit 18, the control unit 18 controls the opening of each of the pressure control valves 17a, 17b to the fuel supply system 13.
The fuel supply pressure supplied from the oxidizer and the oxidant supply pressure supplied from the oxidant supply system 14 are adjusted while ensuring required fuel flow rates and oxidant flow rates. It becomes possible to control the fuel cell electric output characteristics by such a control method. That is, by increasing or decreasing (elevating) the supply pressure of at least one of the fuel and the oxidant, the electric output of the fuel cell can be increased or decreased from the relationship shown in FIG. Therefore, if there is a supply pressure in the fuel supply system 13 and the oxidant supply system 14 enough to maintain the required flow rate of the fuel or the oxidant, the fuel and oxidant of the fuel cell can be instantaneously responded to an increase in external load. 11 is supplied to each of the pressure control valves 17a,
17b. That is, when the external load increases, the load following capability of the fuel cell 11 can be improved, so that the electric output of the fuel cell 11 can be instantaneously increased. The decrease in the output voltage due to the increase in the electric output of the fuel cell 11 or the increase in the output voltage due to the decrease in the electric output of the fuel cell shown in FIG. By increasing and decreasing the supply pressure of the oxidizing agent, it is possible to reduce the variation width of the output voltage of the fuel cell. As a result, the design of the inverter device 12 can be simplified. Although the supply pressure of both the fuel and the oxidant is controlled in the above-described embodiment, it is possible to achieve substantially the same effect as that of the embodiment by controlling either one of the supply pressures. As described above in detail, according to the fuel cell operation / control method of the present invention, the pressure of at least one of the fuel and the oxidant supplied to the fuel cell is controlled. By using the characteristic of (1) increasing the electric power output of the fuel cell due to an increase in the supply pressure of the fuel or the oxidant, it is possible to improve the load followability of the fuel cell when the external load increases, and (2) changing the output voltage of the fuel cell. (3) In particular, a fuel cell capable of applying a pressure difference to the supply pressure of a fuel such as a solid electrolyte or a solid polymer electrolyte, or an oxidizing agent, because the width can be reduced. On the other hand, it has a remarkable effect, such as being extremely effective for improving the external load followability and reducing the output voltage change width.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram showing a fuel cell power generation system used in a fuel cell operation / control method according to an embodiment of the present invention. FIG. 2 is a schematic diagram showing a fuel cell power generation system used in a conventional fuel cell operation / control method. FIG. 3 is a diagram showing general electric output characteristics of a fuel cell. [Description of References] 11 ... fuel cell, 12 ... inverter device, 13 ... fuel supply system, 14 ... oxidant supply system, 17a, 17b ... pressure control valve, 18 ... control device unit.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01M 8/04 H01M 8/10 H01M 8/12

Claims (1)

(57) [Claim 1] An anode electrode, a cathode electrode,
Fuel cell with solid polymer electrolyte interposed between electrodes
And a fuel supply system for supplying fuel to the anode electrode
An oxidizing agent for supplying an oxidizing agent to the cathode
Supply system, residual fuel discharge pipe and residual fuel of the fuel cell
A pressure control interposed in at least one of the oxidant discharge pipes
A roll valve and an inlet connected to the electric output side of the fuel cell.
With a fuel cell power generation system equipped with an inverter device.
A method for operating and controlling a fuel cell, comprising:
Constant supply of fuel and oxidant from the oxidant supply system
In this state, the opening of the pressure control valve is
And / or oxidizer supply pressure is increased
To increase the output voltage under a constant current,
When the output increases and the external load decreases, the fuel supply system and oxidation
Constant supply of fuel and oxidant from the oxidant supply system
In the state, the opening of the pressure control valve is increased to increase the fuel
Supply pressure for at least one of
And lower the output voltage under a constant current to
A method for operating and controlling a fuel cell, comprising reducing output and following an external load .