JP2011023228A - Fuel using flow rate-pressure control, and oxidant circulating fuel cell system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technology capable of constructing a highly-efficient and simple gas circulating fuel cell system. <P>SOLUTION: An output current of a fuel cell 8 is detected with the use of a current detection circuit 16, the flow rate of fuel supplied to the fuel cell 8 is controlled with the use of a flow-rate controller 14 based on the detected result so as pressure of the fuel at a fuel cell inlet 6 to rise, thereby, fuel is stored in circulating paths 10, 11 through a first check valve 2. When the pressure of the fuel at the fuel cell inlet 6 reaches a given upper limit setting value, fuel supply through the flow-rate controller 14 is stopped or the flow rate is controlled to be the flow volume consumed by the fuel cell 8 or less, and the fuel stored in the circulating paths 10, 11 is circulated to the fuel cell 8 through a second check valve 3. When the pressure of the fuel at the fuel cell inlet 6 reaches a given lower limit setting value while decreasing the pressure as the fuel stored in the circulating paths 10, 11 consumed, the fuel supply to the fuel cell 8 is made to restart with the use of the flow-rate controller 14. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a fuel cell system, and more particularly to a recirculation type fuel cell system in which unreacted fuel and oxidant gas discharged from a fuel cell outlet are resupplied to the fuel cell inlet, that is, the gas is circulated.

  A fuel cell is an energy conversion device that utilizes an electrochemical reaction that produces water from hydrogen and oxygen. Hydrogen and oxygen (air) are supplied to extract electricity from the fuel cell, respectively. In general, hydrogen and oxygen are supplied in excess of the amount consumed by the fuel cell. This is to prevent removal of water generated by the fuel cell reaction, damage to the fuel cell due to insufficient supply gas amount, and reduction in power output. However, if the unreacted gas is exhausted out of the system as it is, the energy of the exhausted gas cannot be used effectively. Therefore, the energy efficiency of the fuel cell system is reduced. In order to effectively utilize the energy of unreacted gas, a circulating fuel cell system that re-supplys the gas discharged from the fuel cell outlet to the fuel cell inlet using a pump or an ejector, that is, circulates the gas. Many have been devised.

JP 2004-095528 A JP 2003-178777 A

  However, when the circulation is performed using the pump, the efficiency of the system is lowered because the pump itself consumes a part of the power generated by the fuel cell in order to circulate the gas. Further, since the pump has a movable part, it becomes a source of vibration and noise. The advantages of a fuel cell compared to a conventional heat engine power generator include high efficiency, quietness, no moving parts, etc., but adopting a pump as one of the components of a fuel cell system Therefore, the advantage of the fuel cell is qualitatively offset.

  The ejector can circulate gas without consuming electric power, but the main disadvantage is that the operating range is relatively narrow. There have been proposed ejectors that can operate over a wide range by providing a movable needle, and a system that expands the operating range of the system by using a plurality of ejectors (for example, Patent Documents 1 and 2). However, since these methods cover the narrow characteristics inherent in the ejector with control and system configuration, the control and system become complicated.

  As described above, in order to construct a highly efficient and simple fuel cell system, a circulation system different from the conventional one is desired.

  For example, a circulation system as shown in FIG. 1 using the generation of negative pressure due to gas consumption of a fuel cell without using a pump or an ejector has been proposed (for example, a patent application by the present applicant: Japanese Patent Application No. 2009-049201). issue). As shown in FIG. 1, the fuel cell system includes a hydrogen cylinder 7 in which fuel gas is stored, a pressure regulator 1 that depressurizes high-pressure hydrogen in the hydrogen cylinder 7 and supplies it to the fuel cell 8, and a pressure of the fuel cell 8. , A control device 9 for controlling the pressure of the fuel cell 8 using the pressure regulator 1 based on the detection result of the pressure sensor 5, and a first gas through which the gas discharged from the fuel cell outlet passes. A check valve 2, a circulation path 10 and a circulation path 11 for circulating the gas discharged from the fuel cell outlet to the fuel cell inlet 6, and a gas for separating the gas discharged from the fuel cell outlet and moisture. The liquid separator 4 and the second check valve 3 through which gas passes through the circulation path 11 pass. Here, the circulation path 10 and the circulation path 11 are pipes having a certain internal volume. The above is the configuration on the fuel electrode side, but a similar configuration can be used on the oxygen electrode side.

  However, in this system, circulation is realized by controlling the operating pressure of the fuel cell using a pressure regulator, and an electrically controllable pressure regulator is required. On the other hand, the supply gas in the fuel cell system is often controlled by a flow rate regulator, and it is desirable that the fuel cell system of FIG. 1 be controlled by a flow rate regulator instead of a pressure regulator.

  Accordingly, one object of the present invention is to provide a technique capable of constructing a highly efficient and simple gas circulation fuel cell system. The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

  Of the embodiments disclosed in the present application, the outline of typical ones will be briefly described as follows.

  In the first embodiment of the circulating fuel cell system of the present invention, the output current of the fuel cell is detected by using a current detection circuit, and the fuel to be supplied to the fuel cell by using a flow rate regulator based on the detection result. By controlling the flow rate so that the fuel pressure at the fuel cell inlet increases, the fuel is stored in the circulation path located downstream of the fuel cell via the first check valve, and the fuel pressure at the fuel cell inlet is an arbitrary upper limit. When the set value is reached, the fuel supply via the flow regulator is stopped or controlled below the flow consumed by the fuel cell, and the fuel stored in the circulation path is circulated to the fuel cell via the second check valve, When the fuel pressure at the fuel cell inlet, which decreases as the fuel stored in the circulation path is consumed, reaches an arbitrary lower limit set value, the fuel supply to the fuel cell is resumed using the flow regulator. Function characterized by.

  The second embodiment of the circulating fuel cell system of the present invention uses a flow rate regulator to control the flow rate of fuel supplied to the fuel cell so that the pressure of the fuel at the fuel cell inlet increases. The fuel is stored in the circulation path located at 1 through the first check valve, and when the fuel pressure at the fuel cell inlet reaches an arbitrary upper limit set value, the fuel supply via the flow regulator is stopped or consumed by the fuel cell. The fuel stored in the circulation path is circulated to the fuel cell via the second check valve, and the fuel at the fuel cell inlet decreases as the fuel stored in the circulation path is consumed. When the pressure reaches an arbitrary lower limit set value, the fuel cell functions so as to restart the fuel supply to the fuel cell using the flow rate regulator.

  The third embodiment of the circulating fuel cell system of the present invention detects the output current of the fuel cell using a current detection circuit, and supplies the fuel cell with the flow rate regulator based on the detection result. Is controlled so that the pressure of the oxidant at the fuel cell inlet increases so that the oxidant is stored in the circulation path located downstream of the fuel cell via the first check valve, and the pressure of the oxidant at the fuel cell inlet is stored. When the value reaches any upper limit set value, the supply of oxidant via the flow regulator is stopped or controlled below the flow consumed by the fuel cell, and the oxidant stored in the circulation path is routed through the second check valve. When the pressure of the oxidant at the fuel cell inlet, which is circulated in the fuel cell and decreases as the oxidant stored in the circulation path is consumed, reaches an arbitrary lower limit set value, supply the oxidant to the fuel cell. Flow regulator Stomach, characterized in that it functions to resume.

  In the fourth embodiment of the circulating fuel cell system of the present invention, the flow rate of the oxidant supplied to the fuel cell is controlled by using a flow rate regulator so that the pressure of the oxidant at the fuel cell inlet increases. The oxidant is stored in the circulation path located downstream of the battery via the first check valve, and the oxidant is supplied via the flow regulator when the pressure of the oxidant at the fuel cell inlet reaches an arbitrary upper limit set value. Stop or control below the flow rate consumed by the fuel cell, circulate the oxidant stored in the circulation path to the fuel cell via the second check valve, and as the oxidant stored in the circulation path is consumed When the pressure of the oxidant at the fuel cell inlet to be lowered reaches an arbitrary lower limit set value, the oxidant supply to the fuel cell is resumed by using a flow rate regulator.

  A fifth embodiment of the circulating fuel cell system of the present invention includes any one of the fuel circulation systems (the first and second embodiments) and any one of the oxidant circulation systems (the third and third embodiments). And the fuel and the oxidant are circulated together.

  According to the present invention, it is possible to circulate gas without using a pump or an ejector, so that a highly efficient and simple fuel cell system can be constructed, and at the same time, a flow regulator is used instead of a pressure regulator. This enables flexible system design.

It is a figure which shows the structural example of the fuel cell system examined as a premise of this invention and which does not require a pump and an ejector. It is a figure which shows the structural example of the fuel cell system using the flow regulator by one Embodiment of this invention. In the fuel cell system shown in FIG. 2, when the gas supply is stopped in period II, the flow regulator control signal, the fuel cell pressure, the flow regulator flow, the first check valve flow, the second check valve flow. It is a figure which shows the time change of. It is a figure which shows the flow of the gas in the period I of FIG. It is a figure which shows the flow of the gas in the period II of FIG. In the fuel cell system shown in FIG. 2, the flow rate regulator control signal, the fuel cell pressure, the flow rate regulator flow rate, and the first check valve when the gas supply amount is set to be equal to or less than the fuel cell consumption amount in the period II. It is a figure which shows the time change of a flow volume and a 2nd non-return valve flow volume. It is a figure which shows the flow of the gas in the period II of FIG. It is a figure which shows the structural example of the fuel cell system which controls a flow regulator based only on the detection result of a pressure sensor, and circulates gas, without using the current detection circuit by other embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that components having the same function are denoted by the same reference symbols throughout the drawings for describing the embodiment, and the repetitive description thereof will be omitted.

  FIG. 2 is a diagram showing a configuration example of a fuel cell system according to an embodiment of the present invention. First, an example of the configuration of the fuel cell system according to the present embodiment will be described with reference to FIG.

  In this embodiment, the fuel cell includes a hydrogen electrode to which a fuel such as hydrogen and methane gas is supplied and an oxygen electrode to which an oxidant such as oxygen and air is supplied. In FIG. Only the pole side is shown. Therefore, a configuration similar to that shown in FIG. 2 can be adopted on the oxygen electrode side. In that case, oxygen or air is supplied instead of hydrogen.

  As shown in FIG. 2, the fuel cell system according to the present embodiment includes, for example, a fuel cell 8 that generates power by an electrochemical reaction between hydrogen and oxygen, a load 15 to which power is supplied from the fuel cell 8, A current detection circuit 16 for detecting an output current (or power supply current), a hydrogen cylinder 7 in which fuel gas is stored, a flow regulator 14 for adjusting and supplying hydrogen from the hydrogen cylinder 7 to the fuel cell 8, and a fuel cell 8, a pressure sensor 5 that detects the pressure at the inlet 8 (fuel cell inlet 6), a current detection circuit 16, a control device 9 that controls the flow rate regulator 14 based on the detection results of the pressure sensor 5, and an outlet of the fuel cell 8. The first check valve 2 through which the gas discharged from the (fuel cell outlet 12) (unreacted fuel gas) passes, and the gas discharged from the fuel cell outlet 12 is circulated to the fuel cell inlet 6 Circulation path 10 and The ring path 11, the gas-liquid separator 4 for separating the gas discharged from the fuel cell outlet 12 and moisture, the second check valve 3 through which the gas passed through the circulation path 11 passes, and the like. . Here, the circulation path 10 and the circulation path 11 are pipes having a certain internal volume.

  The flow regulator 14 is connected between the hydrogen cylinder 7 and the fuel cell inlet 6, the pressure sensor 5 is connected to the fuel cell inlet 6, and the first check valve 2 is between the fuel cell outlet 12 and the circulation path 10. The gas-liquid separator 4 is connected between the circulation path 10 and the circulation path 11, and the second check valve 3 is connected between the circulation path 11 and the fuel cell inlet 6. The first check valve 2 is a valve for preventing a backflow, and gas flows only from the fuel cell outlet 12 toward the circulation path 10. Similarly, the second check valve 3 is a valve for preventing a backflow, and gas flows only from the circulation path 11 toward the fuel cell inlet 6. The fuel cell 8 supplies power to the load 15, and the current output from the fuel cell 8 is measured by the current detection circuit 16. The current detection circuit 16 measures current using a shunt resistor, a current sensor, or the like.

  In addition, although the example of hydrogen was demonstrated as gas for fuels in FIG. 2, instead of the hydrogen cylinder 7, other fuel gas, such as methane gas, may be used.

  FIG. 3 shows a control signal (flow rate control signal) for the flow rate regulator 14 output from the control device 9 during operation of the fuel cell system of FIG. 2, the fuel cell pressure, and the gas flow rate via the flow rate regulator 14 ( Flow rate regulator flow rate), the flow rate of gas passing through the first check valve 2 (first check valve flow rate), and the flow rate of gas passing through the second check valve 3 (second check valve flow rate). Show each change. In FIG. 3, the fuel cell pressure is the pressure at the inlet of the fuel cell 8 detected by the pressure sensor 5, but is substantially equal to the pressure of the fuel gas in the fuel cell.

  As shown in FIG. 3, when the fuel cell system according to the present embodiment operates and the fuel cell 8 is generating electric power, the period I and the period II are alternately repeated. FIG. 4 shows how the gas flows in the period I, and FIG. 5 shows how the gas flows in the period II.

  In period I, an amount of fuel corresponding to the signal from the control device 9 is supplied to the fuel cell 8 via the flow rate regulator 14. In general, the amount of gas consumed by a fuel cell is proportional to the current output by the fuel cell. Therefore, if an excessive amount of fuel is supplied in excess of the output current, unreacted fuel is discharged from the outlet of the fuel cell. Will be. In the period I, the control device 9 outputs a control signal to the flow rate regulator 14 based on the detection result of the current detection circuit 16 so as to supply an excess amount of fuel than the fuel consumption of the fuel cell 8, thereby adjusting the flow rate. The fuel is supplied to the fuel cell 8 via the vessel 14. For example, when the output current detected by the current detection circuit 16 is high, the gas supply flow rate through the flow rate regulator 14 is increased by increasing the level of the flow rate control signal output from the control device 9. Conversely, when the output current detected by the current detection circuit 16 is low, the gas supply flow rate through the flow rate controller 14 is reduced by lowering the level of the flow rate control signal output from the control device 9. At this time, as shown in FIG. 4, the gas flows in the manner of the flow rate regulator 14 → the fuel cell inlet 6 → the fuel cell 8 → the fuel cell outlet 12 → the first check valve 2 → the circulation path 10 → the gas-liquid separator 4. → The circulation path 11 When the fuel consumption of the fuel cell 8 (that is, corresponding to the output current) and the supply fuel flow rate via the flow rate regulator 14 are constant, the gas flow rate flowing through the first check valve 2 is also constant as shown in FIG. Thus, the pressure of the fuel cell 8 increases linearly. Since the pressure in the circulation path 11 is lower than the pressure at the fuel cell inlet 6 by the pressure loss of the fuel cell 8, the first check valve 2, the gas-liquid separator 4 and the piping, the second check valve 3 is closed. It becomes a state. As a result, gas does not flow through the second check valve 3. When the pressure of the fuel cell 8 rises due to the fuel supply via the flow rate regulator 14 and the fuel cell pressure detected by the pressure sensor 5 reaches the preset upper limit pressure, the control device 9 When the output is completely stopped or the signal level is lower than that corresponding to the amount of fuel consumed by the fuel cell 8, the period II is entered.

  Regarding the operation in the period II, a case where the output of the control signal (flow rate control signal) from the control device 9 is completely stopped will be described first. When the output of the control signal from the control device 9 is stopped (i.e., becomes zero level), the gas supply through the flow rate regulator 14 is stopped, but the fuel cell 8 continues to consume gas, so the fuel cell 8 Is negative with respect to the circulation path 10 and the circulation path 11. In that case, the flow of gas in the fuel cell system changes as shown in FIG. 5 (period II in FIG. 3). Since the circulation path 10 and the circulation path 11 have internal volumes, during the period II, the gas stored in the circulation path 10 and the circulation path 11 is changed to the circulation path 10 → the gas-liquid separator 4 → the circulation path 11. → Second check valve 3 → Fuel cell inlet 6 → Fuel cell 8 At this time, if the gas consumption in the fuel cell 8 is constant, the flow rate of the gas flowing through the second check valve 3 is constant. Since the pressure at the fuel cell outlet 12 is lower than the pressure in the circulation path 10 by the pressure loss of the gas-liquid separator 4, the second check valve 3, the fuel cell 8 and the piping, the first check valve 2 is closed. It becomes a state. As a result, gas does not flow through the first check valve 2. Then, since the gas supply via the flow rate regulator 14 is stopped, the pressure of the fuel cell 8 decreases, and when the fuel cell pressure detected by the pressure sensor 5 reaches the preset lower limit pressure, the control is performed. The device 9 resumes the output of the control signal.

  Next, a description will be given of a case where the output of the control signal from the control device 9 is not completely stopped for the operation in the period II. In FIG. 6, in the period II, the control for the flow rate regulator 14 output from the control device 9 when the control signal from the control device 9 is set at a signal level lower than the fuel consumption amount of the fuel cell 8. Signal (flow control signal), fuel cell pressure, gas flow through the flow regulator 14 (flow regulator flow), gas flow through the first check valve 2 (first check valve flow), 2 shows temporal changes in the flow rate of gas passing through the check valve 3 (second check valve flow rate). In addition, FIG. 7 shows how the gas flows in the period II at this time. The gas flow through the circulation paths 10 and 11 is the same as that in FIG. 5 except that the gas supply through the flow rate regulator 14 is continued. However, since the amount of gas supplied via the flow rate regulator 14 is smaller than the amount consumed by the fuel cell 8, the fuel cell consumes the gas stored in the circulation path 10 and the circulation path 11 and the pressure decreases. . However, the gradient of the pressure drop is gentle as shown in FIG. 6 due to the presence of gas supply via the flow rate regulator 14 compared to the case of FIG. When the pressure decreases and the fuel cell pressure detected by the pressure sensor 5 reaches a preset lower limit pressure, the control device 9 increases the output of the control signal to a signal level higher than the amount corresponding to the fuel consumption of the fuel cell 8. (Period I).

  The gas stored in the circulation path 10 and the circulation path 11 in the period I corresponds to the gas exhausted from the fuel cell 8, and the gas is supplied again to the fuel cell in the period II. Gas is circulated through. As can be seen from FIGS. 4 to 7, the gas flowing through the circulation path is one-way, and water contained in the circulated gas is removed by the gas-liquid separator 4.

  There is a correlation between the rising / lowering speed of the fuel cell pressure, the gas flow rate flowing through the check valve, and the internal volume of the circulation path (assuming that the internal volume of the fuel cell inlet 6 and the fuel cell outlet 12 is sufficiently small). Specifically, in the period I, when the gas consumption of the fuel cell 8 is constant, the larger the exhaust gas flow rate from the fuel cell, that is, the gas flow rate of the first check valve 2, the greater the circulation between the circulation path 10 and the circulation path 10. The smaller the internal volume of the path 11, the steeper the pressure rise. In the case of the configuration of FIG. 5 in which the gas supply via the flow rate controller 14 is stopped in the period II, the gas flow rate of the second check valve 3 is the same as the gas consumption amount of the fuel cell 8, and the circulation path 10 and the circulation path The larger the internal volume of 11, the slower the rate of decrease of the fuel cell pressure. In the case of the configuration of FIG. 7 in which the gas supply through the flow rate regulator is set lower than the amount corresponding to the consumed fuel amount in the period II, the gas flow rate supplied through the flow rate regulator 14 and the gas flowing through the second check valve 3 The sum of the flow rate is the same as the gas consumption of the fuel cell 8. Similarly, in the case of FIG. 7, the larger the internal volumes of the circulation path 10 and the circulation path 11, the slower the rate of decrease in the fuel cell pressure.

  The length of the period I is determined by the gas consumption of the fuel cell 8, the internal volume of the circulation paths 10 and 11, and the gas supply flow rate via the flow rate regulator 14. When the upper and lower limits of the fuel cell pressure are constant, it is possible to adjust the length of period I by changing the pressure increase gradient of the fuel cell by controlling the gas supply flow rate through the flow rate regulator 14. . For example, by increasing the level of the flow rate control signal output from the control device 9, the gas supply flow rate through the flow rate regulator 14 is increased, the pressure increase gradient of the fuel cell is increased, and the length of the period I is shortened. It is possible. Conversely, by reducing the level of the flow rate control signal output from the control device 9, the gas supply flow rate through the flow rate regulator 14 is reduced, the pressure rise gradient of the fuel cell is reduced, and the length of the period I is increased. Can be lengthened.

  The length of the period II is determined by the gas consumption of the fuel cell 8, the gas supply flow rate via the flow rate regulator 14, and the internal volume of the circulation paths 10 and 11, and controls the gas supply flow rate via the flow rate regulator 14. It can be adjusted by doing. However, the shortest time that the period II can take is when the gas supply flow rate via the flow rate controller 14 is completely stopped, that is, during the operation shown in FIG. 3, and cannot be shorter than that. It is also possible to adjust both the lengths of period I and period II by adjusting the upper and lower limits of the fuel cell pressure.

  As described above, for the sake of simplicity, the fuel cell gas consumption is constant, the flow rate of the first check valve 2 is constant, and the pressure increase in the period I is linear. The fuel cell system of the present invention can operate even when the flow rate of the first check valve 2 is not constant due to fluctuations in the consumption amount. However, in that case, the gradient of the pressure increase of the fuel cell is not constant.

  In the present embodiment, the hydrogen electrode side of the fuel cell has been described. However, the oxygen electrode side to which an oxidant such as air or oxygen is supplied is configured and operated according to the same principle. Is possible.

  Moreover, in the said embodiment, based on the fuel cell pressure detected by the pressure sensor 5, the control apparatus 9 showed the structural example of what is called feedback control in which the control signal output to the flow regulator 14 is changed. However, the characteristics of the fuel cell system may be evaluated in advance, the waveform and timing of the control signal may be set based on the characteristics, and the control signal output to the flow rate regulator 14 may be changed. In this case, the pressure sensor 5 can be dispensed with.

  Moreover, in the said embodiment, based on the electric current value detected by the electric current detection circuit 16, the structural example of what is called feedback control that the control apparatus 9 changes the control signal output to the flow regulator 14 was shown. However, in the configuration as shown in FIG. 8, it is also possible to control based on only the pressure value detected by the pressure sensor 5 without using the detected current value. In order for the system of the present invention to operate, it is necessary to store the gas in the circulation paths 10 and 11 during the period I and to store the gas in the circulation paths 10 and 11, but the detection of the pressure sensor 5 so as to increase the pressure of the fuel cell. The gas may be supplied by controlling the flow controller 14 based on the result.

  As the simplest method, it is conceivable to control the control device 9 so that a larger amount of gas is always supplied during the period I than the maximum consumption gas amount assumed in advance. In other words, since the supply gas flow rate through the flow rate regulator in period I is necessarily greater than the consumption gas amount, the unreacted gas is discharged from the fuel cell and accumulated in the circulation path, so that the pressure of the fuel cell is increased. Will rise.

  In addition, ΔP / ΔT, which is a time (T) derivative when the fuel cell pressure (P) rises, is obtained by calculation or the like, and the gas flow rate through the flow rate regulator 14 is adjusted so that ΔP / ΔT becomes a positive value. There are also methods such as controlling. That is, that ΔP / ΔT is a positive value means that the gas is stored in the circulation paths 10 and 11.

  In the above case, since the gas supply flow rate via the flow rate regulator 14 is not controlled based on the detection result of the current detection circuit 16, the current detection circuit 16 becomes unnecessary (see FIG. 8).

  Therefore, according to the fuel cell system of the present invention, the gas can be circulated without using a pump or an ejector, so that a highly efficient and simple fuel cell system can be constructed. In addition, since no pump or ejector is used, it is quiet and vibration free. In addition, since no moving parts are required (except for the flow controller), the reliability is high. In addition, it consumes less power and can maximize the power generated by the fuel cell (high efficiency). In addition, instead of a pressure regulator, a gas circulation mechanism can be realized by controlling the flow rate of gas supplied to the fuel cell and the pressure of the fuel cell using a flow rate regulator. It becomes possible to design flexibly. Further, since the flow rate regulator is more versatile and less expensive than the pressure regulator, the cost can be reduced.

  As mentioned above, although embodiment in this invention was described concretely, this invention is not limited to the said embodiment, It cannot be overemphasized that it can change variously in the range which does not deviate from the summary.

  INDUSTRIAL APPLICABILITY The present invention is applicable to a fuel cell system that needs to circulate a gas, such as a mobile fuel cell system and a stationary fuel cell system.

  DESCRIPTION OF SYMBOLS 1 ... Pressure regulator, 2 ... 1st check valve, 3 ... 2nd check valve, 4 ... Gas-liquid separator, 5 ... Pressure sensor, 6 ... Fuel cell inlet, 7 ... Hydrogen cylinder, 8 ... Fuel cell, DESCRIPTION OF SYMBOLS 9 ... Control apparatus, 10, 11 ... Circulation path | route, 12 ... Fuel cell exit, 14 ... Flow regulator, 15 ... Load, 16 ... Current detection circuit.

Claims (6)

A fuel cell that is supplied with fuel and oxidant to generate electricity;
A flow rate regulator for regulating the flow rate of fuel supplied to the fuel cell;
A first check valve connected to the outlet of the fuel cell;
A second check valve connected to the inlet of the fuel cell;
A circulation path provided between the first check valve and the second check valve;
A current detection circuit for detecting an output current of the fuel cell;
The output current of the fuel cell is detected using the current detection circuit, and the flow rate of the fuel supplied to the fuel cell using the flow rate controller based on the detection result is determined by the pressure of the fuel at the inlet of the fuel cell. By controlling to increase, fuel is stored in the circulation path via the first check valve, and when the fuel pressure at the inlet of the fuel cell reaches an arbitrary upper limit set value, The fuel supply is stopped or controlled below the flow rate consumed by the fuel cell, and the fuel stored in the circulation path is circulated to the fuel cell via the second check valve and stored in the circulation path. When the fuel pressure at the inlet of the fuel cell, which decreases as the fuel is consumed, reaches an arbitrary lower limit setting value, the fuel supply to the fuel cell is resumed using the flow rate regulator. Fuel cell system, characterized in that the function. A fuel cell that is supplied with fuel and oxidant to generate electricity;
A flow rate regulator for regulating the flow rate of fuel supplied to the fuel cell;
A first check valve connected to the outlet of the fuel cell;
A second check valve connected to the inlet of the fuel cell;
A circulation path provided between the first check valve and the second check valve;
The fuel is stored in the circulation path via the first check valve by controlling the flow rate of the fuel supplied to the fuel cell using the flow regulator so that the pressure of the fuel at the inlet of the fuel cell increases. Then, when the fuel pressure at the inlet of the fuel cell reaches an arbitrary upper limit set value, the fuel supply via the flow regulator is stopped or controlled below the flow consumed by the fuel cell and stored in the circulation path. The fuel pressure is circulated to the fuel cell via the second check valve, and the fuel pressure at the inlet of the fuel cell is lowered as the fuel stored in the circulation path is consumed. A fuel cell system that functions to resume fuel supply to the fuel cell using the flow rate regulator when the value is reached. A fuel cell that is supplied with fuel and oxidant to generate electricity;
A flow controller for adjusting the flow rate of the oxidant supplied to the fuel cell;
A first check valve connected to the outlet of the fuel cell;
A second check valve connected to the inlet of the fuel cell;
A circulation path provided between the first check valve and the second check valve;
A current detection circuit for detecting an output current of the fuel cell;
The current detection circuit is used to detect the output current of the fuel cell, and based on the detection result, the flow rate of the oxidant supplied to the fuel cell using the flow rate regulator is adjusted. By controlling the pressure to increase, the oxidant is stored in the circulation path via the first check valve, and the flow rate when the pressure of the oxidant at the inlet of the fuel cell reaches an arbitrary upper limit set value. The supply of the oxidant via the regulator is stopped or controlled below the flow rate consumed by the fuel cell, and the oxidant stored in the circulation path is circulated to the fuel cell via the second check valve, When the pressure of the oxidant at the inlet of the fuel cell, which decreases as the oxidant stored in the circulation path is consumed, reaches an arbitrary lower limit value, the flow regulator is used to oxidize the fuel cell. Agent Fuel cell system, characterized in that function to resume feeding. A fuel cell that is supplied with fuel and oxidant to generate electricity;
A flow controller for adjusting the flow rate of the oxidant supplied to the fuel cell;
A first check valve connected to the outlet of the fuel cell;
A second check valve connected to the inlet of the fuel cell;
A circulation path provided between the first check valve and the second check valve;
By controlling the flow rate of the oxidant supplied to the fuel cell using the flow rate regulator so that the pressure of the oxidant at the inlet of the fuel cell is increased, the flow path is oxidized via the first check valve. Storing the agent, and controlling the oxidant supply via the flow regulator when the pressure of the oxidant at the inlet of the fuel cell reaches an arbitrary upper limit set value or less than the flow consumed by the fuel cell, The oxidant stored in the circulation path is circulated to the fuel cell via the second check valve, and the oxidation at the inlet of the fuel cell decreases as the oxidant stored in the circulation path is consumed. A fuel cell system that functions to restart supply of an oxidant to the fuel cell using the flow rate regulator when the pressure of the agent reaches an arbitrary lower limit set value. A fuel cell that is supplied with fuel and oxidant to generate electricity;
A first flow controller for adjusting a flow rate of fuel supplied to the fuel cell;
A first check valve connected to the first outlet of the fuel cell;
A second check valve connected to the first inlet of the fuel cell;
A first circulation path provided between the first check valve and the second check valve;
A second flow controller for adjusting the flow rate of the oxidant supplied to the fuel cell;
A third check valve connected to the second outlet of the fuel cell;
A fourth check valve connected to the second inlet of the fuel cell;
A second circulation path provided between the third check valve and the fourth check valve;
A current detection circuit for detecting an output current of the fuel cell;
The output current of the fuel cell is detected using the current detection circuit, and the flow rate of fuel supplied to the fuel cell using the first flow rate regulator based on the detection result is measured at the first inlet of the fuel cell. By controlling the fuel pressure to increase, fuel is stored in the first circulation path via the first check valve, and the fuel pressure at the first inlet of the fuel cell reaches an arbitrary upper limit set value. The fuel supply via the first flow rate regulator is stopped or controlled to be equal to or less than the flow rate consumed by the fuel cell, and the fuel stored in the first circulation path is sent to the fuel via the second check valve. When the fuel pressure at the first inlet of the fuel cell, which is circulated through the battery and decreases as the fuel stored in the first circulation path is consumed, reaches an arbitrary lower limit set value, the first flow rate adjustment Before using the vessel The fuel supply to the fuel cell is restarted,
The output current of the fuel cell is detected using the current detection circuit, and the flow rate of the oxidant supplied to the fuel cell using the second flow rate regulator based on the detection result is determined at the second inlet of the fuel cell. By controlling the oxidant pressure in the fuel cell to increase, the oxidant is stored in the second circulation path via the third check valve, and the oxidant pressure at the second inlet of the fuel cell has an arbitrary upper limit. When the set value is reached, the supply of the oxidant through the second flow rate regulator is stopped or controlled to be equal to or less than the flow rate consumed by the fuel cell, and the oxidant stored in the second circulation path is changed to the fourth reverse flow. The pressure of the oxidant at the second inlet of the fuel cell, which is circulated to the fuel cell via the stop valve and decreases as the oxidant stored in the second circulation path is consumed, reaches an arbitrary lower limit set value. When the second flow rate Fuel cell system, characterized in that function to restart the oxidant supply to the fuel cell with the section unit. A fuel cell that is supplied with fuel and oxidant to generate electricity;
A first flow controller for adjusting a flow rate of fuel supplied to the fuel cell;
A first check valve connected to the first outlet of the fuel cell;
A second check valve connected to the first inlet of the fuel cell;
A first circulation path provided between the first check valve and the second check valve;
A first flow controller for adjusting a flow rate of an oxidant supplied to the fuel cell;
A third check valve connected to the second outlet of the fuel cell;
A fourth check valve connected to the second inlet of the fuel cell;
A second circulation path provided between the third check valve and the fourth check valve;
By controlling the flow rate of fuel supplied to the fuel cell using the first flow rate regulator so that the pressure of the fuel at the first inlet of the fuel cell increases, the first check path is provided in the first circulation path. The fuel is stored via a valve, and when the fuel pressure at the first inlet of the fuel cell reaches an arbitrary upper limit set value, the fuel supply via the first flow regulator is stopped or the flow rate consumed by the fuel cell. Controlled below, the fuel stored in the first circulation path is circulated to the fuel cell via the second check valve, and decreases as the fuel stored in the first circulation path is consumed. When the fuel pressure at the first inlet of the fuel cell reaches an arbitrary lower limit set value, the fuel supply to the fuel cell is resumed using the first flow rate regulator,
By controlling the flow rate of the oxidant supplied to the fuel cell using the second flow rate regulator so that the pressure of the oxidant at the second inlet of the fuel cell is increased, the third circulation path is provided with the third flow rate. The oxidant is stored via a check valve, and when the pressure of the oxidant at the second inlet of the fuel cell reaches an arbitrary upper limit set value, the supply of the oxidant via the second flow rate regulator is stopped or the fuel The oxidant stored in the second circulation path is circulated to the fuel cell via the fourth check valve, and the oxidant stored in the second circulation path is controlled below the flow rate consumed by the battery. When the pressure of the oxidant at the second inlet of the fuel cell, which decreases as it is consumed, reaches an arbitrary lower limit set value, the supply of the oxidant to the fuel cell is resumed using the second flow rate regulator. Features that function as The fuel cell system that.

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