JP2002231277A - Fuel cell system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control the output of a fuel cell stack in a wide range without controlling it in a complicated way. SOLUTION: This fuel cell system is realized by providing a fuel cell stack 1, an air supply passage L3 to supply a prescribed flow of an oxidizer gas to the fuel cell stack 1 in accordance with the power generating condition of the fuel cell stack 1, a hydrogen supply passage L1 to supply a prescribed flow of a fuel gas to the fuel cell stack 1 in accordance with the power generating condition of the fuel cell stack 1, at least two first hydrogen pressure adjusting valves 3, 4 disposed parallel to the hydrogen supply passage L1 to adjust the pressure of the fuel gas to supply to the fuel cell stack 1, a hydrogen circulating passage L2 to circulate the fuel gas to the fuel cell stack 1, a water reservoir 12 to collect moisture contained in the exhaust of the oxidizer electrode and the fuel electrode of the fuel cell stack 1, a water circulating passage L4 to supply water collected by the water reservoir 12 to the fuel cell stack 1, and a control unit 20 to control the opening and closing of the hydrogen pressure adjusting valves 3, 4 in accordance with a requirement for acceleration.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel cell stack which is used, for example, as a driving source of an automobile or the like and is operated by supplying hydrogen gas as a fuel gas and air as an oxidizing gas to generate power. The present invention relates to a fuel cell system that performs pressure regulation.

[0002]

2. Description of the Related Art As a conventional fuel cell system for generating electric power by a fuel cell, those disclosed in, for example, JP-A-7-192743 and JP-A-9-213353 are known.

FIG. 17 shows a main configuration of a fuel cell system disclosed in Japanese Patent Application Laid-Open No. 7-192743.

In this fuel cell system, when operating the fuel cell stack 101, fuel gas is supplied to a port 101a through a fuel tank 102 storing hydrogen, an on-off valve 103, a pressure regulating valve 104, a pump 105, and a deionizing filter 106. And a fuel gas system for supplying the fuel gas to the pump 105 again from the port 101b via the gas-liquid separator 107. In this fuel cell system, surplus fuel gas exhausted without being used in the fuel cell stack 101 is circulated.

Next, FIG. 18 shows a main configuration of a fuel cell system disclosed in Japanese Patent Application Laid-Open No. 9-213353.

In this fuel cell system, the ejector pump 111 circulates hydrogen. A recirculation gas pressure gauge 114 is provided in a recirculation gas flow path 113 provided between the exhaust gas outlet of the fuel electrode 112a and the ejector pump 111, and the ejector is controlled in accordance with a value measured by the recirculation gas pressure gauge 114. The pressure control is performed by sending a control signal to the raw fuel supply valve of the pump 111 to adjust the opening degree and control the raw fuel supply amount. Also, the recirculation gas flow control valve 11
5 and a recirculation gas flow meter 116 for controlling the recirculation gas flow control valve 115 to adjust the flow rate of the recirculation gas corresponding to the load of the fuel cell 112.

[0007]

However, the above conventional example has the following problems.

In the fuel cell system disclosed in Japanese Patent Application Laid-Open No. 7-192743, when the fuel cell stack 101 has a full load range, that is, when the fuel gas flow rate is in a range from a small flow rate to a large flow rate, the hydrogen in the fuel cell stack 101 is reduced. The pressure at the entrance is controlled by one pressure control valve 104.
Therefore, if the pressure control valve 104 that enables the pressure control on the small flow rate side is used, the pressure control on the large flow rate side becomes impossible, and the pressure control valve 104 that enables the pressure control on the large flow rate side is used.
However, when the fuel cell system is used, pressure control on the small flow rate side cannot be performed, and there is a problem that the fuel cell system does not function sufficiently.

In the fuel cell system disclosed in Japanese Patent Application Laid-Open No. 7-192743, the pump 105 also needs to vary the circulation amount from a small flow rate to a large flow rate, so that the pump 105 is inevitably increased in size. There is. Further, there is a problem that the water in the fuel gas causes friction and corrosion in the sliding portion of the pump, and the performance of the pump 105 is deteriorated.

In the fuel cell system disclosed in Japanese Patent Application Laid-Open No. 9-213353, the ejector pump 111 is used as a hydrogen circulating device. Performance does not drop.

However, the amount of hydrogen circulated is controlled by the outlet pressure of the ejector pump 111 using the circulating part flow control valve, and the amount of hydrogen is controlled by the circulating part pressure by the inlet metering mechanism of the ejector pump 111. Because
It is necessary to control these balances so as to satisfy the required hydrogen pressure, supply hydrogen flow rate, and hydrogen circulation amount of the fuel cell stack 112, and there is a problem that the control becomes very complicated.

Accordingly, the present invention has been proposed in view of the above-described circumstances, and without performing complicated control,
An object of the present invention is to provide a fuel cell system capable of controlling output of a fuel cell stack over a wide range.

[0013]

According to a first aspect of the present invention, there is provided a fuel cell system comprising: a fuel cell in which a fuel electrode and an oxidizer electrode are sandwiched with an electrolyte membrane interposed therebetween; Oxidant gas supply means for supplying a predetermined flow rate of oxidant gas to the fuel cell according to the power generation state of the battery; and fuel gas for supplying a predetermined flow rate of fuel gas to the fuel cell according to the power generation state of the fuel cell Supply means, a plurality of pressure regulating valves which are arranged in parallel at the subsequent stage of the fuel gas supply means and adjust the pressure of the fuel gas supplied to the fuel cell, and circulate the fuel gas through the fuel cell; Means, the oxidizer electrode of the fuel cell, a water recovery means for recovering water contained in exhaust gas from the fuel electrode, and a water supply means for supplying the fuel cell with the water recovered by the water recovery means. And the outside Control means for controlling the opening degree of each pressure regulating valve according to the fuel cell output request, thereby satisfying the entire range of the fuel gas pressure required by the fuel cell output request by a combination of the opening degrees of the plurality of pressure regulating valves. And

According to a second aspect of the present invention, there is provided a fuel cell system in which a fuel electrode and an oxidant electrode are opposed to each other with an electrolyte membrane interposed therebetween, and a oxidant gas having a predetermined flow rate according to the power generation state of the fuel cell. Oxidant gas supply means for supplying the fuel cell, fuel gas supply means for supplying a predetermined flow rate of fuel gas to the fuel cell according to the power generation state of the fuel cell, supply of the fuel gas to the fuel cell A small pressure regulating valve for adjusting the pressure of the fuel gas when the flow rate is a small flow rate; and a small pressure regulating valve provided in parallel with the small pressure regulating valve, and a supply flow rate of the fuel gas to the fuel cell is larger than that of the small pressure regulating valve. A large pressure regulating valve for adjusting the pressure of the fuel gas when the flow rate is a flow rate, a circulating means for circulating the fuel gas to the fuel cell, the oxidizer electrode of the fuel cell, and the exhaust gas from the fuel electrode. Water that collects moisture A collection unit, a water supply unit that supplies the water collected by the water collection unit to the fuel cell, and an opening degree of the small pressure regulating valve and the large pressure regulating valve according to an external fuel cell output request. A control means that satisfies the entire range of the fuel gas pressure required by the fuel cell output request by a combination of the opening degree of the small pressure regulating valve and the opening degree of the large pressure regulating valve.

In the fuel cell system according to claim 3, the control means fully closes the large pressure regulating valve and regulates the pressure with the small pressure regulating valve within a fuel gas flow rate range which can be regulated by the small pressure regulating valve. In the fuel gas flow rate range that can be regulated by the large pressure regulating valve, the small pressure regulating valve is fully opened and the pressure is regulated by the large pressure regulating valve.

In the fuel cell system according to a fourth aspect, the control means fully closes the large pressure regulating valve and regulates the pressure with the small pressure regulating valve within a fuel gas flow rate range which can be regulated by the small pressure regulating valve. In the fuel gas flow rate range that can be regulated by the large pressure regulating valve, the small pressure regulating valve is fully closed and the pressure is regulated by the large pressure regulating valve.

In a fuel cell system according to a fifth aspect of the present invention, a shutoff valve is provided at a stage subsequent to the large pressure regulating valve, and the control means closes the shutoff valve when the large pressure regulating valve is not operating, and controls the large pressure regulating valve. When the pressure valve is operating, control is performed to open the shut valve.

In the fuel cell system according to the present invention, a fuel cell in which a fuel electrode and an oxidant electrode are opposed to each other with an electrolyte membrane interposed therebetween, and a oxidant gas having a predetermined flow rate in accordance with a power generation state of the fuel cell. Oxidizing gas supply means for supplying the fuel cell, fuel gas supply means for supplying a predetermined flow rate of fuel gas to the fuel cell according to the power generation state of the fuel cell, A plurality of pressure regulating valves arranged to adjust the pressure of the fuel gas supplied to the fuel cell;
A plurality of ejector pumps having the same characteristics, which are disposed at the subsequent stage of each pressure regulating valve and are supplied with surplus fuel gas from the fuel cell and circulate through the fuel cell, the oxidizer electrode of the fuel cell, and the fuel electrode A plurality of shutoff valves provided between each of the ejector pumps and the fuel cell for opening and closing the supply of excess fuel gas from each of the ejector pumps; A combination of a plurality of pressure control valves by controlling the opening of each pressure control valve in response to a fuel cell output request from the outside, and a water supply means for supplying the water recovered by the recovery means to the fuel cell. A control means that satisfies the entire range of the fuel gas pressure required for the fuel cell output request. Meet fuel gas circulation flow in.

In the fuel cell system according to the present invention, a fuel cell in which a fuel electrode and an oxidant electrode are opposed to each other with an electrolyte membrane interposed therebetween, and a oxidant gas having a predetermined flow rate depending on the power generation state of the fuel cell. Oxidizing gas supply means for supplying the fuel cell, fuel gas supply means for supplying a predetermined flow rate of fuel gas to the fuel cell according to the power generation state of the fuel cell, A plurality of pressure regulating valves arranged to adjust the pressure of the fuel gas supplied to the fuel cell;
A small ejector pump for circulating surplus fuel gas from the fuel cell when the fuel gas is supplied at a small flow rate, and a surplus fuel gas from the fuel cell when the fuel gas is supplied at a high flow rate A large ejector pump for circulating water, the oxidizer electrode of the fuel cell, water recovery means for recovering water contained in exhaust gas from the fuel electrode, and a water recovery means provided between each of the ejector pumps and the fuel cell. A plurality of shut-off valves for opening and closing the supply of excess fuel gas from each ejector pump, water supply means for supplying the water recovered by the water recovery means to the fuel cell, and a fuel cell output request in response to an external fuel cell output request. Control means for controlling the opening degree of each pressure regulating valve to satisfy the entire range of the fuel gas pressure required for the fuel cell output request with a combination of the opening degrees of the plurality of pressure regulating valves; Serial in combination with the circulation flow rate and circulation rate of the large ejector pump miniature ejector pump, satisfy the fuel gas circulation flow rate of the entire range required by the fuel cell output demand.

[0020] In the fuel cell system according to claim 8, the plurality of pressure regulating valves are a small pressure regulating valve for regulating the pressure of the fuel gas when the fuel gas is supplied to the fuel cell at a small flow rate. The pressure of the fuel gas when the gas is supplied to the fuel cell at a large flow rate is a large pressure regulating valve, and the control means controls the small pressure regulating valve and the large pressure regulating valve in response to an external fuel cell output request. By controlling the opening degree, the combination of the opening degree of the small pressure regulating valve and the opening degree of the large pressure regulating valve satisfies the entire range of the fuel gas pressure required for the fuel cell output request.

In the fuel cell system according to a ninth aspect, the small ejector pump is provided at a stage subsequent to the small pressure regulating valve.
The pressure controllable range of the small pressure regulating valve and the fuel gas flow rate range that is the circulatable range of the small ejector pump are substantially equivalent, and the pressure controllable range of the large pressure regulating valve and the circulatable range of the large ejector pump are Are almost the same.

In the fuel cell system according to the tenth aspect,
The control means completely closes the large pressure regulating valve within a fuel gas flow rate range in which the pressure regulation and circulation amount can be adjusted by the small pressure regulating valve and the small ejector pump, and is provided at a circulation port of the large ejector pump. The shut valve provided at the circulation port of the small ejector pump is fully opened, and the small pressure regulating valve and the small ejector pump are controlled to regulate the pressure and the amount of circulation. In the fuel gas flow rate range where the pressure regulation and the circulation amount can be adjusted by the large ejector pump, the small pressure regulating valve is fully opened, and the shut valve provided at the circulation port of the large ejector pump is fully opened, and the small ejector is opened. The shutoff valve provided at the circulation port of the pump is fully closed, and control is performed to adjust the pressure regulation and circulation amount by the large pressure regulating valve and the large ejector pump.

In the fuel cell system according to claim 11,
The control means completely closes the large pressure regulating valve within a fuel gas flow rate range in which the pressure regulation and circulation amount can be adjusted by the small pressure regulating valve and the small ejector pump, and is provided at a circulation port of the large ejector pump. The shut valve provided at the circulation port of the small ejector pump is fully opened, and the small pressure regulating valve and the small ejector pump are controlled to regulate the pressure and the amount of circulation. Within the fuel gas flow rate range where the pressure regulation and circulation amount can be adjusted by the large ejector pump, the small pressure regulating valve is fully closed, and the shut valve provided at the circulation port of the large ejector pump is fully opened, and the small The shut valve provided at the circulation port of the ejector pump is fully closed, and control is performed to adjust the pressure regulation and circulation amount by the large pressure regulating valve and the large ejector pump.

In the fuel cell system according to the twelfth aspect,
A shut valve is provided between the large pressure regulating valve and the large ejector pump.

In the fuel cell system according to claim 13,
The control means completely closes the large pressure regulating valve within a fuel gas flow rate range in which the pressure regulation and circulation amount can be adjusted by the small pressure regulating valve and the small ejector pump, and is provided at a circulation port of the large ejector pump. The shut valve provided at the circulation port of the small ejector pump is fully opened, and the shut valve between the large pressure regulating section valve and the large ejector pump is completely closed, whereby the small regulating valve is closed. The pressure regulator and the small ejector pump are controlled to adjust the pressure regulation and the circulation amount, and the small pressure regulator valve is fully opened within the range of the fuel gas flow rate where the pressure regulation and the circulation amount can be adjusted by the large pressure regulation valve and the large ejector pump. The shut valve provided in the circulation port of the large ejector pump is fully opened, the shut valve provided in the circulation port of the small ejector pump is fully closed, and the large pressure regulating section valve and the large ejector are closed. Fully open shutoff valve between the pump and controls to adjust the pressure regulating and circulation quantity with the large pressure regulating valve and large ejector pump.

In the fuel cell system according to claim 14,
The control means completely closes the large pressure regulating valve within a fuel gas flow rate range in which the pressure regulation and circulation amount can be adjusted by the small pressure regulating valve and the small ejector pump, and is provided at a circulation port of the large ejector pump. The shut valve provided at the circulation port of the small ejector pump is fully opened, and the shut valve between the large pressure regulating section valve and the large ejector pump is completely closed, whereby the small regulating valve is closed. The pressure regulating valve and the small ejector pump are controlled so as to adjust the pressure regulation and the circulation amount. Within the fuel gas flow rate range in which the pressure regulation and the circulation amount can be regulated by the large pressure regulating valve and the large ejector pump, the small pressure regulating valve is fully controlled. The shut valve provided at the circulation port of the large ejector pump is fully opened, the shut valve provided at the circulation port of the small ejector pump is fully closed, and the large pressure regulating section valve and the large ejector are closed. Fully open shutoff valve between the pump and controls to adjust the pressure regulating and circulation quantity with the large pressure regulating valve and large ejector pump.

In the fuel cell system according to claim 15,
A fuel cell in which a fuel electrode and an oxidant electrode are opposed to each other with an electrolyte membrane interposed therebetween, and oxidant gas supply means for supplying a predetermined flow rate of oxidant gas to the fuel cell according to the power generation state of the fuel cell; Fuel gas supply means for supplying a predetermined flow rate of fuel gas to the fuel cell according to the power generation state of the fuel cell; and a pressure of the fuel gas supplied to the fuel cell which is arranged in parallel at a stage subsequent to the fuel gas supply means. A plurality of pressure regulating valves to adjust the
A plurality of ejector pumps disposed between the pressure regulating valves and the fuel cell to circulate the fuel gas; a plurality of shut valves disposed at a stage subsequent to each of the ejector pumps; and an oxidizing agent for the fuel cell. An electrode, a water collecting means for collecting water contained in the exhaust gas from the fuel electrode, a water supply means for supplying the water collected by the water collecting means to the fuel cell, and a fuel cell output request from the outside. Controlling the opening degree of each pressure regulating valve in response to the control means to satisfy the entire range of the fuel gas pressure required for the fuel cell output request by a combination of the opening degrees of the plurality of pressure regulating valves; The combination of the circulating flow rates of the ejector pumps satisfies the fuel gas circulating flow rate in the entire range required by the fuel cell output demand.

In the fuel cell system according to claim 16,
The plurality of pressure regulating valves are a small pressure regulating valve that adjusts the pressure of the fuel gas when the supply of the fuel gas to the fuel cell is a small flow rate, and the supply rate of the fuel gas to the fuel cell is a large flow rate. It is a large pressure regulating valve that regulates the pressure of the fuel gas in the case.

[0029] In the fuel cell system according to claim 17,
The plurality of ejector pumps include a small ejector pump that circulates excess fuel gas from the fuel cell when the fuel gas is supplied at a small flow rate, and a small ejector pump that circulates the excess fuel gas when the fuel gas is supplied at a large flow rate. A large ejector pump that circulates excess fuel gas from the fuel cell.

In the fuel cell system according to the eighteenth aspect,
The pressure controllable range of the small pressure regulating valve and the fuel gas flow rate range that is the circulatable range of the small ejector pump are substantially equal, and the pressure controllable range of the large pressure regulating valve and the circulable range of the large ejector pump are almost the same. Are almost the same.

[0031] In the fuel cell system according to claim 19,
The control means fully closes a shut valve provided at a subsequent stage of the large ejector pump within a fuel gas flow rate range in which the pressure regulation and the circulation amount can be adjusted by the small pressure regulating valve and the small ejector pump. Fully open the shut valve provided at the subsequent stage of the ejector pump, and control the pressure regulation and the circulation amount with the small pressure regulating valve and the small ejector pump,
In the large gas pressure regulating valve, the fuel gas flow rate range in which the pressure regulation and the circulation amount can be adjusted by the large ejector pump, the shut valve provided in the subsequent stage of the large ejector pump is fully opened,
The shut valve provided at the subsequent stage of the small ejector pump is fully closed, and the large pressure regulating valve and the large ejector pump are controlled to regulate the pressure and the circulation amount.

In the fuel cell system according to claim 20,
The control means fully closes a shut valve provided at a subsequent stage of the large ejector pump within a fuel gas flow rate range in which the pressure regulation and the circulation amount can be adjusted by the small pressure regulating valve and the small ejector pump. Fully open the shut valve provided at the subsequent stage of the ejector pump, and control the pressure regulation and the circulation amount with the small pressure regulating valve and the small ejector pump,
In the large gas pressure regulating valve, the fuel gas flow rate range in which the pressure regulation and the circulation amount can be adjusted by the large ejector pump, the shut valve provided in the subsequent stage of the large ejector pump is fully opened,
The shut valve provided at the subsequent stage of the small ejector pump is fully closed, and the large pressure regulating valve and the large ejector pump are controlled to regulate the pressure and the circulation amount.

[0033]

According to the fuel cell system of the first aspect, by controlling the opening of each pressure regulating valve in response to a fuel cell output request from the outside, the opening of a plurality of pressure regulating valves can be combined. Since the entire range of the fuel gas pressure required by the fuel cell output requirement is satisfied, even if the required fuel gas flow rate is extremely large, it is possible to cope with a large flow rate and improve the degree of freedom of the system performance that can be achieved. be able to. Further, according to this fuel cell system, since a plurality of pressure regulating valves having the same characteristics are provided in parallel, even if the required output range of the fuel cell is wide, it is possible to stably adjust the fuel gas flow rate and pressure widely. And the performance of the fuel cell can be fully exhibited.

According to the fuel cell system of the second aspect, the opening degree of the small pressure regulating valve and the large regulating valve is controlled by controlling the opening of the small pressure regulating valve and the large pressure regulating valve in response to an external fuel cell output request. In combination with the opening degree of the pressure valve, the fuel gas pressure required in the fuel cell output request is satisfied in the entire range, so even if the output required for the fuel cell becomes wider,
The fuel gas flow rate and pressure can be adjusted more stably in a wider range, and the performance of the fuel cell can be sufficiently exhibited.

According to the fuel cell system of the third aspect, within the fuel gas flow rate range that can be regulated by the small pressure regulating valve,
The large pressure regulator is fully closed and the pressure is regulated by the small pressure regulator. Within the fuel gas flow rate range that can be regulated by the large pressure regulator, the small pressure regulator is fully opened and the pressure is regulated by the large pressure regulator. It is possible to provide a stable fuel cell system without causing an abrupt change in pressure when switching pressure regulation from a small pressure regulating valve to a large pressure regulating valve.

According to the fuel cell system of the fourth aspect, within the fuel gas flow rate range that can be regulated by the small pressure regulating valve,
The large pressure regulating valve is fully closed and the pressure is regulated by the small pressure regulating valve. Within the fuel gas flow rate range that can be regulated by the large pressure regulating valve, the small pressure regulating valve is fully closed and the pressure is regulated by the large pressure regulating valve to enable each regulating valve. Since control is performed one by one in the operation range, the control logic can be simplified. Further, according to this fuel cell system, power consumption can be reduced when each regulating valve is closed, and pressure can be regulated by a usable regulating valve even when one of the regulating valves becomes unusable. It can also be used as a fail-safe mechanism.

According to the fuel cell system of the fifth aspect, the shut-off valve is closed when the large pressure regulating valve is not operating, and the shut valve is opened when the large pressure regulating valve is operating. Since the leakage amount at the time of fully closing is larger than, for example, at the time of the small flow rate controlled by the small pressure regulating valve, it is possible to prevent the control by the small pressure regulating valve from becoming impossible.

According to the fuel cell system of the sixth aspect, the combination of the circulating flow rates of the plurality of ejector pumps provides
The configuration satisfies the fuel gas circulation flow rate in the entire range required by the fuel cell output requirements. And the degree of freedom in system performance can be improved. Further, according to this fuel cell system, by providing pressure regulating valves having the same characteristics in parallel, a wide fuel gas flow rate can be realized, and the performance of the fuel cell can be sufficiently exhibited. Further, according to this fuel cell system, even if the output required for the fuel cell is widened, the performance of the fuel cell can be sufficiently exhibited by using the ejector pump having the same characteristics.

According to the fuel cell system of the present invention, by controlling the opening of each pressure regulating valve in response to a fuel cell output request from the outside, the fuel cell system can be combined with the opening of a plurality of pressure regulating valves. It satisfies the entire range of the fuel gas pressure required for the output request, and the combination of the circulating flow rate of the small ejector pump and the circulating flow rate of the large ejector pump provides the fuel gas circulating flow rate in the entire range required for the fuel cell output request. As a result, even if the output required of the fuel cell is wider, the output can be dealt with, and the performance of the fuel cell can be sufficiently exhibited.

According to the fuel cell system of the present invention, the opening degree of the small pressure regulating valve and the large regulating valve are controlled by controlling the opening of the small pressure regulating valve and the large pressure regulating valve in response to an external fuel cell output request. In combination with the opening degree of the pressure valve, the entire range of the fuel gas pressure required for the fuel cell output request is satisfied. Therefore, even if the output required for the fuel cell is wider, it can be dealt with. Performance can be fully exhibited.

According to the fuel cell system of the ninth aspect, the small ejector pump is provided at the subsequent stage of the small pressure regulating valve, and the pressure adjustable range of the small pressure regulating valve and the fuel gas flow rate range which can be circulated by the small ejector pump. Are almost the same, and the pressure controllable range of the large pressure regulating valve and the fuel gas flow rate range that is the circulatable range of the large ejector pump are almost the same, so even if the output required for the fuel cell is wider, Corresponding fuel gas flow rate, pressure, and circulation amount can be realized, and the performance of the fuel cell can be sufficiently exhibited.

According to the fuel cell system according to the tenth aspect, the fuel gas can be reliably circulated by the ejector pump used in the flow rate range, and even when the flow rate is large, the fuel gas passes through the small pressure regulating valve. Since the amount of fuel gas to be reduced can be reduced from the flow rate flowing through the large pressure regulator, the large pressure regulator can be reduced in size and pressure loss, and the pressure difference when switching from the small pressure regulator to the large pressure regulator can be eliminated. .

According to the fuel cell system of the eleventh aspect, it is possible to reliably and stably circulate the fuel gas by the ejector pump used in the flow rate range, simplify the control logic, and reduce the power consumption. Can be provided with a fail-safe mechanism when the pressure regulating valve becomes unusable.

According to the fuel cell system of the twelfth aspect, since the shut-off valve is provided between the large pressure regulating valve and the large ejector pump, when the large pressure regulating valve is fully closed, the fuel from the large pressure regulating valve is provided. Deterioration of pressure regulation accuracy of the small pressure regulator due to variation in gas leakage can be suppressed.

According to the fuel cell system of the thirteenth aspect, the shut-off valve is closed when the large pressure regulating valve is not operating, so that the amount of leakage when the large pressure regulating valve is fully closed is controlled by, for example, a small pressure regulating valve. When the flow rate is larger than the flow rate, it is possible to prevent the control with the small pressure regulating valve from becoming impossible.

According to the fuel cell system of the present invention, the shut-off valve is closed when the large pressure regulating valve is not operating, and the shut valve is opened when the large pressure regulating valve is operating. Since the leakage amount at the time of fully closing is larger than, for example, at the time of the small flow rate controlled by the small pressure regulating valve, it is possible to prevent the control by the small pressure regulating valve from becoming impossible.

According to the fuel cell system of the fifteenth aspect, since a plurality of shut-off valves are provided downstream of each ejector pump, the pressure regulating valve and the ejector pump to be used are determined according to the fuel gas flow rate. , The control logic can be simplified, and a fail-safe function can be provided.

According to the fuel cell system of the sixteenth aspect, the plurality of pressure regulating valves adjust the pressure of the fuel gas when the fuel gas is supplied to the fuel cell at a small flow rate.
The large pressure regulating valve regulates the fuel gas pressure when the fuel gas is supplied to the fuel cell at a large flow rate.This satisfies the entire range of the fuel gas pressure required by the fuel cell output requirement, Even if the required output is wide, the fuel gas flow rate and pressure can be widely and stably adjusted, and the performance of the fuel cell can be sufficiently exhibited.

According to the fuel cell system of the seventeenth aspect, the plurality of ejector pumps are a small ejector pump for circulating surplus fuel gas from the fuel cell when the fuel gas is supplied at a small flow rate, and Is a large ejector pump that circulates excess fuel gas from the fuel cell when the fuel gas is supplied at a large flow rate. Can be demonstrated.

According to the fuel cell system of the eighteenth aspect, the pressure controllable range of the small pressure regulating valve is substantially equal to the fuel gas flow rate range of the small ejector pump circulating range. Since the possible range and the fuel gas flow rate range which is the circulatable range of the large ejector pump are almost equal, even if the output required for the fuel cell is wider,
Corresponding fuel gas flow rate, pressure, and circulation amount can be realized, and the performance of the fuel cell can be sufficiently exhibited.

According to the fuel cell system of the present invention, since the shut-off valve is closed when the large pressure regulating valve is not operating, the amount of leakage when the large pressure regulating valve is fully closed is controlled by, for example, a small pressure regulating valve. When the flow rate is larger than the flow rate, it is possible to prevent the control with the small pressure regulating valve from becoming impossible.

According to the fuel cell system of the present invention, the shut-off valve is closed when the large pressure regulating valve is not operating, and the shut-off valve is opened when the large pressure regulating valve is operating. Since the leakage amount at the time of fully closing is larger than, for example, at the time of the small flow rate controlled by the small pressure regulating valve, it is possible to prevent the control by the small pressure regulating valve from becoming impossible.

[0053]

Embodiments of the present invention will be described below with reference to the drawings.

[First Embodiment of Fuel Cell System] FIG.
1 shows a configuration of the fuel cell system according to the first embodiment of the present invention.

The fuel cell stack 1 has a structure in which a plurality of solid polymer electrolyte membranes are stacked with a fuel cell structure in which an oxidizer electrode and a fuel electrode are installed in pairs sandwiched between separators. In the fuel cell stack 1, the oxidizing gas is supplied to the oxidizing electrode, and the fuel gas is supplied to the fuel electrode side to generate power. In the fuel cell stack 1 of the fuel cell system to which the present invention is applied, hydrogen gas is used as a fuel gas,
Air containing oxygen is used as the oxidant gas.

In this fuel cell system, the hydrogen cylinder 2, the first hydrogen pressure regulating valve 3 and the second hydrogen pressure regulating valve 4, the hydrogen circulating device 5, the humidifier 6, and the fuel cell stack 1 are inserted through the hydrogen flow pipe and the hydrogen The supply channel L1 is configured, and the fuel cell stack 1, the hydrogen gas-based water recovery device 7, and the hydrogen circulation device 5 are inserted through a hydrogen channel tube to configure the hydrogen circulation channel L2.

In such a fuel cell system, when operating the fuel cell stack 1, the hydrogen gas pressure is regulated from the hydrogen cylinder 2 by the first hydrogen regulating valve 3 or the second hydrogen regulating valve 4, and the hydrogen circulating device is operated. A hydrogen gas is supplied to the fuel cell stack 1 via the humidifier 5 and the humidifier 6. Excess hydrogen gas exhausted without being used in the fuel cell stack 1 is circulated again to the hydrogen circulation device 5 via the hydrogen gas water recovery device 7. The humidifier 6 includes a semipermeable membrane, and when hydrogen gas and air pass, water molecules pass through the semipermeable membrane and humidify each gas.

The fuel cell system further includes a compressor 8 for taking in air from outside. In the compressor 8, the taken-in air is supplied to the humidifier 6 through the air supply flow path L3. In the humidifier 6, the air is humidified and supplied to the fuel cell stack 1. Exhaust air not used in the fuel cell stack 1 is supplied to the air flow path water recovery device 9 and the air pressure regulating valve 1.
The gas is exhausted to the outside through the zero.

Since the surplus hydrogen gas contains water vapor and liquid water in addition to the hydrogen gas, the surplus hydrogen gas is collected by the hydrogen gas water recovery device 7 and discharged to the water storage 12 through the drain valve 11. Further, since the discharged air contains water vapor and liquid water, it is collected by the air flow path water recovery device 9 and discharged to the water storage 12 via the drain valve 13.

Further, in the fuel cell system, the water stored in the water storage unit 12 is supplied to the fuel cell stack 1 by the water pump 14, and after cooling the fuel cell stack 1, the humidifier 6 partially cools the fuel cell stack 1. Consumption, and water storage 1 except for consumption
2 and a water circulation channel L4 for circulating the water. Also,
The water pumped from the water reservoir 12 by the water pump 14 is
Since the fuel cell stack 1 is heated by cooling, it is cooled by the radiator 15 and the cooling fan 16.

Further, in the fuel cell system, a hydrogen pressure sensor 17 for measuring a hydrogen gas pressure supplied from the humidifier 6 to the fuel cell stack 1 and an air pressure supplied from the humidifier 6 to the fuel cell stack 1 are measured. It has an air pressure sensor 18 for measuring and an air flow sensor 19 for measuring the air flow taken in by the compressor 8.

Further, the fuel cell system includes a control unit 20 for controlling the above-mentioned components. The control unit 20 receives a sensor signal from a hydrogen pressure sensor 17, an air pressure sensor 18, an air flow rate sensor 19, a sensor for detecting a power generation state of the fuel cell stack 1 (not shown), and accelerator opening information from the outside. First hydrogen pressure regulating valve 3, second hydrogen pressure regulating valve 4, air pressure regulating valve 10
Is controlled to adjust the hydrogen pressure and the air pressure so as to satisfy the required output value of the fuel cell stack 1 in accordance with the power generation state of the fuel cell stack 1. Further, the control unit 20 controls the number of revolutions of the compressor 8 to adjust the air flow rate according to the power generation state of the fuel cell stack 1.

In the fuel cell system thus configured, two first hydrogen pressure regulating valves 3 and two second hydrogen pressure regulating valves 4 are installed in parallel, and the first hydrogen pressure regulating valve 3 and the second hydrogen pressure regulating valve 3 are controlled by the control unit 20. By controlling the operation of the hydrogen pressure regulating valve 4, the output required value of the fuel cell stack 1 is large even if the flow rate dynamic range per one of the first hydrogen pressure regulating valve 3 and the second hydrogen pressure regulating valve 4 is narrow. This corresponds to a case where the required flow rate of hydrogen gas in the stack 1 is very large.

Since the response of a narrow pressure regulating valve is faster than that of a pressure regulating valve having a wide flow rate dynamic range, the first hydrogen pressure regulating valve 3 and the second hydrogen pressure regulating valve 4 installed in parallel are connected as described above. By making the flow rate dynamic narrow, a fuel cell system capable of coping with a large flow rate while maintaining good responsiveness is provided.

Here, the first hydrogen pressure regulating valve 3 is a small pressure regulating valve of a low flow rate type having the flow-pressure control characteristic shown in FIG. 2A, and the second hydrogen pressure regulating valve 4 is shown in FIG. 2B. Assuming that a large flow regulating valve of a high flow rate type having the above-described flow-pressure control characteristic is used, by controlling the first hydrogen pressure regulating valve 3 and the second hydrogen pressure regulating valve 4, the flow rate-pressure control characteristic shown in FIG. Will have. In this case, if the range of the operable region (X + Y) is the width of the required hydrogen gas flow rate,
The output of the fuel cell stack 1 can be controlled in a wide range. In consideration of smoothness of the pressure control, it is preferable that the operable range X and the operable range Y overlap each other.

[Control Example of Control Unit 20] As shown in FIG. 3, the first hydrogen pressure regulating valve 3 is a small pressure regulating valve of a low flow rate type and the second hydrogen pressure regulating valve 4 is a large pressure regulating valve of a high flow rate type. 4 shows a flowchart of a control example of the control unit 20 in the case.

First, the control unit 20 inputs a required fuel cell output value by obtaining accelerator opening information and the like in step S0, and then outputs a required output of the fuel cell stack 1 and a target hydrogen flow rate (pressure). Is calculated (step S1). When the target hydrogen flow rate is within the range X, the control unit 20 controls the first hydrogen pressure regulating valve 3
The second hydrogen pressure regulating valve 4 sends out a control signal to bring it into a fully closed state, and controls the first hydrogen pressure regulating valve 3 and the second hydrogen pressure regulating valve 4 (step S2, step S3).

When the target hydrogen flow rate is not in the range X but in the range Y, the control unit 20
A control signal for controlling the pressure by the second hydrogen pressure control valve 4 and bringing the first hydrogen pressure control valve 3 to the fully open state is sent out, and the first hydrogen pressure control valve 3 and the second
Control the hydrogen pressure regulating valve 4 (Step S2, Step S2)
4).

By controlling the first hydrogen pressure regulating valve 3 and the second hydrogen pressure regulating valve 4 as described above, when the hydrogen gas flow rate is in the range Y, the first hydrogen pressure regulating valve 3 is fully opened. In this case, the flow rate of the hydrogen gas flowing through the second hydrogen pressure regulating valve 4, which is a large pressure regulating valve, can be reduced, and the second hydrogen pressure regulating valve 4 can be reduced in size and reduced in pressure loss.

Further, when switching from the first hydrogen pressure regulating valve 3 to the second hydrogen pressure regulating valve 4, the state of the first hydrogen pressure regulating valve 3 is open, so that there is no pressure switching step and the connection of pressure is improved. be able to.

[Other Control Examples of Control Unit 20] FIG. 4 shows a case where the first hydrogen pressure regulating valve 3 is a small pressure regulating valve of a low flow rate type and the second hydrogen pressure regulating valve 4 is a large pressure regulating valve of a high flow rate type. 5 shows a flowchart of another control example of the control unit 20.

In this control example, in step S14 where it is determined that the target hydrogen flow rate is within the range Y, the control unit 20 regulates the pressure with the second hydrogen pressure regulating valve 4 and performs the first hydrogen regulation.
A control signal is sent so that the hydrogen pressure regulating valve 3 is fully closed, and the first hydrogen pressure regulating valve 3 and the second hydrogen pressure regulating valve 4 are controlled. Except for the operation in step S14, the operation is the same as the operation shown in the flowchart of FIG.

By controlling the first hydrogen pressure regulating valve 3 and the second hydrogen pressure regulating valve 4 in this manner, the first hydrogen pressure regulating valve 3 and the second hydrogen pressure regulating valve 3 are controlled.
The control method of the hydrogen pressure regulating valve 4 is simplified because it is independently controlled within each of the possible operating ranges. When each valve is normally closed, power consumption can be reduced. Further, even if one of the pressure regulating valves is damaged, the pressure can be controlled within the range in which the pressure of the undamaged valve can be regulated although the battery output of the fuel cell stack 1 is limited. Can be.

[Second Embodiment of Fuel Cell System] FIG.
Next, a configuration of a fuel cell system according to a second embodiment of the present invention is shown.

The second embodiment has the same configuration as that of the first embodiment except that a shut-off valve 31 is provided after the second hydrogen pressure regulating valve 4 of the fuel cell system shown in the first embodiment. The shut-off valve 31 is connected to the control unit 2
The operation is controlled by a control signal transmitted from 0.

[Control Example of Control Unit 20] FIG. 6 shows that in the fuel cell system according to the second embodiment, the first hydrogen pressure regulating valve 3 is a low flow rate small pressure regulating valve, and the second hydrogen pressure regulating valve 4 is a high flow rate type. 4 shows a flowchart of a control example in the case of a large pressure regulating valve.

First, the control unit 20 inputs a required fuel cell output value by obtaining accelerator opening information and the like in step S20, and then calculates a required output of the fuel cell stack 1 and a target hydrogen flow rate. (Step S21). If the target hydrogen flow rate is in the range X, the control unit 20 regulates the pressure with the first hydrogen pressure regulating valve 3, and sends a control signal for setting the second hydrogen pressure regulating valve 4 and the shutoff valve 31 to the fully closed state, so that the first hydrogen pressure regulation is performed. The pressure control valve 3, the second hydrogen pressure control valve 4, and the shutoff valve 31 are controlled (Step S22, Step S23).

When the target hydrogen flow rate is in the range Y, the control unit 20 regulates the pressure with the second hydrogen pressure regulating valve 4,
A control signal for causing the first hydrogen pressure regulating valve 3 and the shutoff valve 31 to be fully opened is sent out to control the first hydrogen pressure regulating valve 3, the second hydrogen pressure regulating valve 4 and the shutoff valve 31 (step S22, step S24).

By controlling the first hydrogen pressure regulating valve 3, the second hydrogen pressure regulating valve 4 and the shutoff valve 31 as described above, the first hydrogen pressure regulating valve 3 is fully opened when the target hydrogen flow rate is in the range Y. Since the flow rate of hydrogen flowing through the second hydrogen pressure regulating valve 4, which is a large pressure regulating valve, can be reduced even at the time of flow rate, the second hydrogen pressure regulating valve 4 can be reduced in size and reduced in pressure loss.

Further, when switching from the first hydrogen pressure regulating valve 3 to the second hydrogen pressure regulating valve 4, the state of the first hydrogen pressure regulating valve 3 is open, so that there is no pressure switching step and the connection of pressure is improved. And shut valve 3
Since the valve 1 is closed, if the amount of leakage when the second hydrogen pressure regulating valve 4 is fully closed is larger than, for example, a small flow rate to be controlled by the first hydrogen pressure regulating valve 3, the control by the first hydrogen pressure regulating valve 3 is not performed. Although it is no longer possible, it can be suppressed, so that extremely low load operation of the fuel cell stack 1 can be realized.

[Another Control Example of Control Unit 20] FIG. 7 shows a fuel cell system according to the second embodiment in which the first hydrogen pressure regulating valve 3 is a small pressure regulating valve of a low flow rate type.
4 shows a flowchart of a control example of the control unit 20 when the second hydrogen pressure regulating valve 4 is a high-pressure type large pressure regulating valve.

In this control example, in step S34, the control unit 20 regulates the pressure by the second hydrogen pressure regulating valve 4, and causes the first hydrogen pressure regulating valve 3 to be fully closed and the shutoff valve 31 to be fully open. To control the first hydrogen pressure regulating valve 3, the second hydrogen pressure regulating valve 4, and the shutoff valve 31.
Except for the operation in step S34, the operation is the same as the operation shown in the flowchart of FIG.

By controlling the first hydrogen pressure regulating valve 3, the second hydrogen pressure regulating valve 4 and the shutoff valve 31 in this manner, independently of the first hydrogen pressure regulating valve 3 and the second hydrogen pressure regulating valve 3 within the respective possible operating ranges.
Since the hydrogen pressure regulating valve 4 is controlled, the control logic can be simplified. When each valve is normally closed, power consumption can be reduced. Further, even if one of the pressure regulating valves is damaged, the pressure can be controlled within the range in which the pressure of the undamaged valve can be regulated although the battery output of the fuel cell stack 1 is limited. Can be.

Although the above description has been made on the case where the characteristics of the first hydrogen pressure regulating valve 3 and the second hydrogen pressure regulating valve 4 are different, the same effect can be obtained by combining a plurality of pressure regulating valves having the same characteristics. It goes without saying that it can be obtained.

[Third Embodiment of Fuel Cell System] FIG. 8
Next, a configuration of a fuel cell system according to a third embodiment of the present invention is shown.

In the third embodiment, the first hydrogen regulator 3 and the second hydrogen regulator 4 of the fuel cell system according to the first embodiment are used.
The ejector pump 41 and the ejector pump 42 are respectively installed at the subsequent stage, and the hydrogen circulation passage L2 is further branched to form a hydrogen circulation passage L of the ejector pump 41 and the ejector pump 42.
The second embodiment is different from the first embodiment in that a first shutoff valve 43 and a second shutoff valve 44 are provided in a circulation port passing through the second shutoff valve 2.

The operation of the first shut-off valves 43 and 44 is controlled by a control signal 8c sent from the control unit 20.

In the third embodiment, each of the first hydrogen pressure regulating valve 3, the second hydrogen pressure regulating valve 4, the ejector pump 41 and the ejector pump 42, and the flow rate dynamic range and the circulation flow rate dynamic range in which the pressure can be regulated are set. Even if it is narrow, it can cope with a case where the required maximum flow rate and maximum circulation amount of hydrogen of the fuel cell stack 1 are very large.

Further, since the response of a narrow pressure regulating valve is faster than that of a pressure regulating valve having a wide flow rate dynamic range, the first hydrogen pressure regulating valve 3 and the second hydrogen pressure regulating valve 4 installed in parallel are connected as described above. By setting the flow rate dynamic to be narrow, a fuel cell system capable of coping with a large flow rate while maintaining good responsiveness can be provided.

FIG. 9 shows the characteristics when the ejector pumps 41 and 42 are used and the characteristics when the ejector pumps 41 and 42 are used in combination. Here, the ejector pumps 41 and 42 circulate the excess hydrogen gas from the fuel cell stack 1 at the circulation flow rate Q2 when the supply flow rate Q1 shown in FIG.
3 is supplied to the fuel cell stack 1, and pressure losses P1, P2, and P3 are applied to the supply flow rate Q1, the circulation flow rate Q2, and the output flow rate Q3. FIG.
(A), (c), and (e) show the relationship between the circulating hydrogen flow rate Q2 and the supply hydrogen flow rate Q1, and FIGS. 9B and 9D show the relationship between the supply flow rate Q1 and the pressure losses P1 to P3.

FIG. 9 (a) and FIG.
If the ejector pump 42 is a low flow type having ejector characteristics shown in FIG. 9B and the ejector pump 42 is a high flow type having ejector characteristics shown in FIGS. 9C and 9D, the ejector pumps 41 and 42 are 9 (e). In this case, the output of the fuel cell stack 1 can be controlled over a wide range if the required hydrogen gas flow rate is within the operable range (G + H). It is preferable that the drivable range G and the drivable range H overlap each other in consideration of smooth drivability.

The operable range of the ejector pumps 41 and 42 is determined as follows. For example, from the relationship between the supply flow rate Q1 and the target circulation flow rate Q2 shown in FIG. 9A, the point at which the ejector pump can be satisfied, that is, the flow rate lower limit value A is determined. If it is less than this, it will be offline with respect to the target circulation flow rate Q2.

Further, from the relationship between the supply flow rate Q1 and the ejector pressure loss P3-P1 shown in FIG.
An allowable differential pressure E is determined. As a result, the flow rate upper limit B is determined, and the operable range G of the ejector pump is determined.

Here, the operable range X of the first hydrogen pressure regulating valve 3 shown in FIG. 2A is substantially equal to the operable range G of the ejector pump 41, and the first range shown in FIG. 2
Operating range Y of the hydrogen pressure regulating valve 4 and the ejector pump 42
It is possible to set the operable range H of
It is necessary from the viewpoint of circulation amount control.

[Control Example in Third Embodiment] FIG. 10
In the fuel cell system shown as the third embodiment, the first hydrogen pressure regulating valve 3 is a low flow rate type small pressure regulating valve, the second hydrogen pressure regulating valve 4 is a high flow rate type large pressure regulating valve, and the ejector pump 41 is a low flow rate type. 4 shows a flowchart of a control example when the ejector pump 42 is of a high flow rate type.

First, the control unit 20 inputs the required fuel cell output value by obtaining the accelerator opening information and the like in step S40, and then calculates the required fuel cell stack output and target hydrogen flow rate (step S40). S
41). When the target hydrogen flow rate is in the range X, the control unit 20 regulates the pressure with the first hydrogen pressure regulating valve 3, fully closes the second hydrogen pressure regulating valve 4, fully opens the first shutoff valve 43, and activates the second shutoff valve 44. Sends a control signal to fully close,
The first hydrogen pressure regulating valve 3, the second hydrogen pressure regulating valve 4, the first shutoff valve 43 and the second shutoff valve 44 are controlled (step S4).
2. Step S43).

When the target hydrogen flow rate is in the range Y, the control unit 20 regulates the pressure with the second hydrogen pressure regulating valve 4,
The first hydrogen pressure regulating valve 3 sends a control signal to make it fully open, the first shutoff valve 43 makes a fully closed state, the second shutoff valve 44 sends out a control signal to make it fully open, and the first hydrogen pressure regulating valve 3, the second hydrogen pressure regulating valve 4, First
The shut valve 43 and the second shut valve 44 are controlled (Step S42, Step S44).

Here, the shut-off valve is switched according to the ejector pump to be used. For example, when circulating with the ejector pump 41, the second shut valve 44 is closed so as not to circulate with the ejector pump 42, so that the circulation is reliably performed with the ejector pump. Stabilized fuel cell stack 1
The deterioration of performance is suppressed.

By controlling the first hydrogen pressure regulating valve 3 and the second hydrogen pressure regulating valve 4 in this manner, when the hydrogen gas flow rate is in the range Y, since the first hydrogen pressure regulating valve 3 is fully opened, the second shutoff valve 4
4 is a large pressure regulating valve even when the flow is
Since the amount of hydrogen gas flowing through the hydrogen pressure regulating valve 4 can be reduced, the size and pressure loss of the second hydrogen pressure regulating valve 4 can be reduced.

Further, when switching from the first hydrogen pressure regulating valve 3 to the second hydrogen pressure regulating valve 4, the state of the first hydrogen pressure regulating valve 3 is open, so that there is no pressure switching step and the connection of pressure is good. can do.

"Control Example in Third Embodiment" FIG. 11
In the fuel cell system shown in the third embodiment, the first hydrogen pressure regulating valve 3 is a small pressure regulating valve of a low flow rate type, the second hydrogen pressure regulating valve 4 is a large pressure regulating valve of a high flow rate type, and the ejector pump 43 is low. A flow chart of a control example when the flow rate type and the ejector pump 44 are a high flow rate type is shown.

In this control example, in step S54, the control unit 20 regulates the pressure with the second hydrogen pressure regulating valve 4 and sends out a control signal so that the first hydrogen pressure regulating valve 3 is fully closed. The hydrogen pressure regulating valve 3 and the second hydrogen pressure regulating valve 4 are controlled. Except for the operation in step S54, the operation is the same as the operation shown in the flowchart of FIG.

By controlling the first hydrogen pressure regulating valve 3 and the second hydrogen pressure regulating valve 4 in this manner, the first hydrogen pressure regulating valve 3 and the second hydrogen pressure regulating valve 3 are controlled.
The control method of the hydrogen pressure regulating valve 4 is simplified because it is independently controlled within each of the possible operating ranges. When each valve is normally closed, power consumption can be reduced. Furthermore, even when one of the pressure regulating valves is damaged, the pressure can be controlled within the pressure regulating range of the undamaged valve, although the battery output of the fuel cell stack 1 is limited, so that it is used as a fail-safe mechanism. Can be.

[Fourth Embodiment of Fuel Cell System] FIG.
FIG. 2 shows a configuration of a fuel cell system according to a fourth embodiment of the present invention. In the fourth embodiment, the configuration is the same as that of the third embodiment except that a third shutoff valve 45 is provided after the second hydrogen pressure regulating valve 4 of the fuel cell system shown in the third embodiment shown in FIG. It is.

"Seventh Control Example in Fourth Embodiment" FIG. 1
3 shows the first embodiment of the fuel cell system shown as the fourth embodiment.
Control example in which the hydrogen pressure regulating valve 3 is a small pressure regulating valve of a low flow rate type, the second hydrogen pressure regulating valve 4 is a large pressure regulating valve of a high flow rate type, the ejector pump 41 is a low flow rate type, and the ejector pump 42 is a high flow rate type. The flowchart of FIG.

The control unit 20 determines in step S
In step 60, the required fuel cell output value is input by obtaining accelerator opening information and the like, and then the required fuel cell stack output and target hydrogen flow rate are calculated (step S6).
1). If the target hydrogen flow rate is in the range X, the control unit 20 regulates the pressure with the first hydrogen pressure regulating valve 3, the second hydrogen pressure regulating valve 4 is fully closed, the first shutoff valve 43 is fully open, and the second
The shut-off valve 44 sends out a control signal to make it fully closed, and the third shut-off valve 45 sends out a control signal to make it fully closed.
Hydrogen pressure regulating valve 4, first shut-off valve 43, second shut-off valve 4
The fourth and third shut valves 45 are controlled (step S6).
2. Step S63).

If the target hydrogen flow rate is in the range Y, the control unit 20 regulates the pressure with the second hydrogen pressure regulating valve 4,
The first hydrogen pressure regulating valve 3 sends a control signal to fully open the state, the first shutoff valve 43 to the fully closed state, the second shutoff valve 44 to the fully open state, and the third shutoff valve 45 to the fully open state. 3, the second hydrogen pressure regulating valve 4, the first shut valve 43, the second
The shut valve 44 and the third shut valve 45 are controlled (Step S62, Step S64).

In FIG. 14, the first hydrogen pressure regulating valve 3 of the fuel cell system shown in the third embodiment is a small pressure regulating valve of a low flow rate type, and the second hydrogen pressure regulating valve 4 is a large pressure regulating valve of a high flow rate type. A flow chart of a control example when the ejector pump 41 is a low flow type and the ejector pump 42 is a high flow type is shown.

In this embodiment, in step S74, the control unit 20 regulates the pressure with the second hydrogen pressure regulating valve 4 and sends out a control signal so that the first hydrogen pressure regulating valve 3 is fully closed. The hydrogen pressure regulating valve 3 and the second hydrogen pressure regulating valve 4 are controlled. Except for the operation in step S74, the operation is the same as the operation shown in the flowchart of FIG.

As shown in the flow charts of FIGS. 13 and 14, when the second hydrogen pressure regulating valve 4 is not operated, the second
If the amount of leakage when the hydrogen pressure regulating valve 4 is fully closed is larger than, for example, a small flow rate to be controlled by the first hydrogen pressure regulating valve 3, the control by the first hydrogen pressure regulating valve 3 cannot be performed.
Is closed, so that it can be suppressed.

[Fifth Embodiment of Fuel Cell System] FIG.
FIG. 5 shows a configuration of a fuel cell system according to a fifth embodiment of the present invention.

The fifth embodiment is different from the third embodiment shown in FIG. 8 in that a fourth shut-off valve 46 is provided downstream of the ejector pump 41 and a fifth shut-off valve 47 is installed downstream of the ejector pump 42. Different from form.

In the fuel cell system according to the fifth embodiment, the pressure regulating valve and the ejector pump to be used can be determined according to the target hydrogen flow rate, so that the control logic becomes simple. Further, even when one of the pressure regulating valve and the ejector pump is damaged and cannot be used, the output of the fuel cell stack 1 is limited. However, the pressure regulation and circulation within the possible range of the usable pressure regulating valve and the ejector pump are possible. Volume control is possible. Therefore, this fuel cell system has a fail-safe mechanism.

Here, the above description is based on the first hydrogen pressure regulating valve 3,
Although the case where the characteristics of the second hydrogen pressure regulating valve 4, the ejector pump 41, and the ejector pump 42 are different is described, a plurality of pressure regulating valves 3, 4 and the ejector pumps 41, 42 having the same characteristics as shown in FIG. It goes without saying that the same effect can be obtained by the combination.

The above embodiment is an example of the present invention. For this reason, the present invention is not limited to the above-described embodiment, and other than the present embodiment, various modifications may be made according to the design and the like within a range not departing from the technical idea according to the present invention. Can be changed.

For example, a combination of three or more ejector pumps and pressure regulating valves is conceivable irrespective of the same characteristics or different characteristics.

[Brief description of the drawings]

FIG. 1 is a block diagram for explaining a main configuration of a fuel cell system shown as a first embodiment of the present invention.

2A is a diagram showing a flow rate-pressure control characteristic of a low flow rate type pressure regulating valve, and FIG. 2B is a view showing a flow rate-pressure control characteristic of a high flow rate type pressure regulating valve. It is the figure which showed, and (c) is the figure which showed the flow-pressure control characteristic at the time of combining and using the low flow type pressure regulating valve and the high flow type pressure regulating valve.

FIG. 3 is a flowchart illustrating an example of control by a control unit in the fuel cell system.

FIG. 4 is a flowchart for explaining another control example by the control unit in the fuel cell system.

FIG. 5 is a block diagram showing a configuration of a fuel cell system according to a second embodiment in the present invention.

FIG. 6 is a flowchart illustrating an example of control by a control unit in the fuel cell system.

FIG. 7 is a flowchart for explaining another control example by the control unit in the fuel cell system.

FIG. 8 is a block diagram showing a configuration of a fuel cell system according to a third embodiment in the present invention.

FIG. 9 shows (a) and (b) in the fuel cell system.
FIGS. 4A and 4B are diagrams showing ejector characteristics of a low flow type ejector pump, and FIGS. 4C and 4D are diagrams showing ejector characteristics of a high flow type ejector pump; FIGS.
FIG. 4 is a diagram showing ejector characteristics when a low flow type ejector pump and a high flow type ejector pump are used in combination.

FIG. 10 is a flowchart illustrating an example of control by a control unit in the fuel cell system.

FIG. 11 is a flowchart for explaining another control example by the control unit in the fuel cell system.

FIG. 12 is a block diagram showing a configuration of a fuel cell system according to a fourth embodiment of the present invention.

FIG. 13 is a flowchart illustrating an example of control by a control unit in the fuel cell system.

FIG. 14 is a flowchart showing another control example by the control unit in the fuel cell system.

FIG. 15 is a block diagram illustrating a configuration of a fuel cell system according to a fifth embodiment in the present invention.

FIG. 16 is a block diagram showing a main configuration of the fuel cell system when a pressure regulating valve and an ejector pump having the same characteristics are used.

FIG. 17 is a block diagram for explaining a main configuration of a first fuel cell system shown as a conventional technique.

FIG. 18 is a block diagram for explaining a main configuration of a second fuel cell system shown as a conventional technique.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fuel cell stack 2 Hydrogen cylinder 3 First hydrogen pressure regulating valve 4 Second hydrogen pressure regulating valve 5 Hydrogen circulation device 6 Humidifier 7 Hydrogen gas type water recovery device 8 Compressor 9 Air flow channel water recovery device 10 Air pressure control valve 11 Drain valve 12 Water reservoir 13 Drain valve 14 Water pump 15 Radiator 16 Cooling fan 17 Hydrogen pressure sensor 18 Air pressure sensor 19 Air flow sensor 20 Control unit 31 Shut valve 41 Ejector pump 42 Ejector pump 43 First shut valve 44 Second shut valve 45th 3 shut valve 46 4th shut valve 47 5th shut valve

Claims (20)

[Claims] 1. A fuel cell in which a fuel electrode and an oxidant electrode are opposed to each other with an electrolyte membrane interposed therebetween, and an oxidant for supplying a predetermined flow rate of an oxidant gas to the fuel cell according to a power generation state of the fuel cell. Gas supply means, fuel gas supply means for supplying a predetermined flow rate of fuel gas to the fuel cell according to the power generation state of the fuel cell, and fuel gas supply means A plurality of pressure regulating valves having the same characteristics for adjusting the pressure of the fuel gas to be circulated; circulating means for circulating the fuel gas to the fuel cell; and the oxidizer electrode of the fuel cell and the exhaust gas from the fuel electrode. A water collecting means for collecting the water collected by the water collecting means; a water supply means for supplying the water collected by the water collecting means to the fuel cell; and an opening of each pressure regulating valve in response to a fuel cell output request from the outside. By doing so, The fuel cell system characterized by comprising a combination of opening of the pressure regulating valve, and control means to meet the full range of the fuel gas pressure required by the fuel cell output request. 2. A fuel cell in which a fuel electrode and an oxidant electrode are opposed to each other with an electrolyte membrane interposed therebetween, and an oxidant for supplying a predetermined flow rate of an oxidant gas to the fuel cell according to a power generation state of the fuel cell. Gas supply means, fuel gas supply means for supplying a predetermined flow rate of fuel gas to the fuel cell in accordance with the power generation state of the fuel cell, and supply flow rate of the fuel gas to the fuel cell is small. A small pressure regulating valve for adjusting the pressure of the fuel gas; and a fuel gas when the supply flow rate of the fuel gas to the fuel cell is larger than that of the small pressure regulating valve, provided in parallel with the small pressure regulating valve. A large pressure regulating valve for adjusting pressure; a circulating means for circulating the fuel gas to the fuel cell; a oxidizing electrode of the fuel cell; and a water collecting means for collecting water contained in exhaust gas from the fuel electrode. And the water recovery means Therefore, by controlling the opening degree of the small pressure regulating valve and the large pressure regulating valve in response to a fuel cell output request from the outside, the opening degree of the small pressure regulating valve And the opening of the large pressure regulator,
Control means for satisfying the entire range of the fuel gas pressure required by the fuel cell output request. 3. The control means, when the fuel gas flow rate is adjustable by the small pressure regulating valve, fully closes the large pressure regulating valve, regulates the pressure by the small pressure regulating valve, and regulates the pressure by the large pressure regulating valve. Within the range of possible fuel gas flows,
3. The fuel cell system according to claim 2, wherein the control is performed such that the small pressure regulating valve is fully opened and the pressure is regulated by the large pressure regulating valve. 4. The control means, when the fuel gas flow rate is adjustable by the small pressure regulating valve, fully closes the large pressure regulating valve, regulates the pressure by the small pressure regulating valve, and regulates the pressure by the large pressure regulating valve. Within the range of possible fuel gas flows,
3. The fuel cell system according to claim 2, wherein the control is performed such that the small pressure regulating valve is fully closed and the pressure is regulated by the large pressure regulating valve. 5. A shut-off valve provided at a stage subsequent to the large-sized pressure regulating valve, wherein the control means closes the shut-off valve when the large-sized pressure regulating valve is not operating, and closes the shut-off valve when the large-sized pressure regulating valve is activated. The fuel cell system according to any one of claims 2 to 4, wherein the control is performed to open the shut valve. 6. A fuel cell in which a fuel electrode and an oxidant electrode are opposed to each other with an electrolyte membrane interposed therebetween, and an oxidant for supplying a predetermined flow rate of an oxidant gas to the fuel cell according to a power generation state of the fuel cell. Gas supply means, fuel gas supply means for supplying a predetermined flow rate of fuel gas to the fuel cell according to the power generation state of the fuel cell, and fuel gas supply means A plurality of pressure regulating valves for adjusting the pressure of the fuel gas to be supplied; and An oxidizer electrode of the fuel cell; a water collecting means for collecting water contained in exhaust gas from the fuel electrode; and a surplus fuel of each ejector pump provided between each of the ejector pumps and the fuel cell. Gas supply A plurality of shut-off valves that open and close, a water supply unit that supplies the water collected by the water recovery unit to the fuel cell, and an opening degree of each of the pressure regulating valves in response to an external fuel cell output request. A control means that satisfies the entire range of the fuel gas pressure required for the fuel cell output request by a combination of the opening degrees of the plurality of pressure regulating valves, and a combination of the circulating flow rates of the plurality of ejector pumps,
A fuel cell system which satisfies a fuel gas circulation flow rate in a whole range required by a fuel cell output request. 7. A fuel cell in which a fuel electrode and an oxidant electrode are opposed to each other with an electrolyte membrane interposed therebetween, and an oxidant for supplying an oxidant gas at a predetermined flow rate to the fuel cell according to a power generation state of the fuel cell. Gas supply means, fuel gas supply means for supplying a predetermined flow rate of fuel gas to the fuel cell according to the power generation state of the fuel cell, and fuel gas supply means A plurality of pressure regulating valves for adjusting the pressure of the fuel gas to be supplied; a small ejector pump for circulating surplus fuel gas from the fuel cell when the fuel gas is supplied at a small flow rate; A large ejector pump that circulates excess fuel gas from the fuel cell when supplied, the oxidizer electrode of the fuel cell, and a water recovery unit that recovers water contained in exhaust gas from the fuel electrode. A plurality of shut valves provided between each of the ejector pumps and the fuel cell for opening and closing the supply of excess fuel gas from each of the ejector pumps; and a water supply for supplying the water collected by the water collecting means to the fuel cell. Means for controlling the opening degree of each pressure regulating valve in response to a fuel cell output request from the outside, so that the total of the fuel gas pressure required for the fuel cell output request can be obtained by combining the opening degrees of the plurality of pressure regulating valves. Control means that satisfies the range, and the combination of the circulating flow rate of the small ejector pump and the circulating flow rate of the large ejector pump satisfies the fuel gas circulating flow rate in the entire range required by the fuel cell output request. Fuel cell system. 8. The small pressure regulating valve for regulating the pressure of the fuel gas when the supply of the fuel gas to the fuel cell is a small flow rate, and the supply of the fuel gas to the fuel cell. Is a large pressure regulating valve the pressure of the fuel gas when is a large flow rate, by controlling the opening degree of the small pressure regulating valve and the large pressure regulating valve according to the fuel cell output request from the outside, The fuel cell system according to claim 7, wherein the combination of the opening degree of the small pressure regulating valve and the opening degree of the large pressure regulating valve satisfies the entire range of the fuel gas pressure required for the fuel cell output request. 9. The small ejector pump is provided at a stage subsequent to the small pressure regulating valve, and a pressure regulating range of the small pressure regulating valve is substantially equal to a fuel gas flow rate range which is a circulating range of the small ejector pump. 9. The fuel cell system according to claim 8, wherein a pressure adjustable range of the large pressure regulating valve is substantially equal to a fuel gas flow rate range which is a circulatable range of the large ejector pump. 10. The control means closes the large pressure regulating valve fully within a fuel gas flow rate range in which the pressure regulation and the circulation amount can be adjusted by the small pressure regulating valve and the small ejector pump. The shut valve provided at the circulation port is fully closed, the shut valve provided at the circulation port of the small ejector pump is fully opened, and the pressure regulation and the circulation amount are controlled by the small pressure regulating valve and the small ejector pump. Within the fuel gas flow rate range where the pressure regulation and circulation amount can be adjusted by the large pressure regulating valve and the large ejector pump, the small pressure regulating valve is fully opened, and the shut valve provided at the circulation port of the large ejector pump is fully opened. The shut-off valve provided in the circulation port of the small ejector pump is fully closed, and the large pressure regulating valve and the large ejector pump are controlled to adjust the pressure regulation and the circulation amount. The fuel cell system of claim 8 wherein. 11. The control means closes the large pressure regulating valve fully within a fuel gas flow rate range in which the pressure regulation and the circulation amount can be adjusted by the small pressure regulating valve and the small ejector pump. The shut valve provided at the circulation port is fully closed, the shut valve provided at the circulation port of the small ejector pump is fully opened, and the pressure regulation and the circulation amount are controlled by the small pressure regulating valve and the small ejector pump. In the fuel gas flow rate range in which the pressure regulation and the circulation amount can be adjusted by the large pressure regulating valve and the large ejector pump, the small pressure regulating valve is fully closed, and a shut valve provided at a circulation port of the large ejector pump is provided. The valve is fully opened, the shut valve provided at the circulation port of the small ejector pump is fully closed, and the large pressure regulating valve and the large ejector pump are controlled to adjust the pressure regulation and the circulation amount. The fuel cell system of claim 8 wherein. 12. The fuel cell system according to claim 7, further comprising a shutoff valve between the large pressure regulating valve and the large ejector pump. 13. The large pressure regulating valve is fully closed within a fuel gas flow rate range in which the pressure regulation and the circulation amount can be adjusted by the small pressure regulating valve and the small ejector pump. The shut valve provided at the circulation port is fully closed, the shut valve provided at the circulation port of the small ejector pump is fully opened, and the shut valve between the large pressure regulating section valve and the large ejector pump is fully closed. Then, the small pressure regulating valve and the small ejector pump are controlled so as to regulate the pressure regulation and the circulation amount, and the large pressure regulating valve and the large ejector pump can regulate the pressure regulation and the circulation amount within the range of the fuel gas flow rate which can be regulated. The small pressure regulating valve is fully opened, the shut valve provided in the circulation port of the large ejector pump is fully opened, the shut valve provided in the circulation port of the small ejector pump is fully closed, and the large pressure regulating valve is opened. The fully open shutoff valve between the large ejector pump, the fuel cell system of claim 12, wherein the controller controls so as to adjust the pressure regulating and circulation quantity with the large pressure regulating valve and large ejector pump. 14. The control means closes the large pressure regulating valve fully within a fuel gas flow rate range in which the pressure regulation and the circulation amount can be adjusted by the small pressure regulating valve and the small ejector pump. The shut valve provided at the circulation port is fully closed, the shut valve provided at the circulation port of the small ejector pump is fully opened, and the shut valve between the large pressure regulating section valve and the large ejector pump is fully closed. Then, the small pressure regulating valve and the small ejector pump are controlled so as to regulate the pressure regulation and the circulation amount, and the large pressure regulating valve and the large ejector pump can regulate the pressure regulation and the circulation amount within the range of the fuel gas flow rate which can be regulated. The small pressure regulating valve is fully closed, the shut valve provided in the circulation port of the large ejector pump is fully opened, the shut valve provided in the circulation port of the small ejector pump is fully closed, and the large pressure regulating valve is opened. The fully open shutoff valve between the large ejector pump, the fuel cell system of claim 12, wherein the controller controls so as to adjust the pressure regulating and circulation quantity with the large pressure regulating valve and large ejector pump. 15. A fuel cell in which a fuel electrode and an oxidant electrode are opposed to each other with an electrolyte membrane interposed therebetween, and an oxidant for supplying a predetermined flow rate of an oxidant gas to the fuel cell according to a power generation state of the fuel cell. Gas supply means, fuel gas supply means for supplying a predetermined flow rate of fuel gas to the fuel cell according to the power generation state of the fuel cell, and fuel gas supply means A plurality of pressure regulating valves for adjusting the pressure of the fuel gas to be supplied; a plurality of ejector pumps disposed between the respective pressure regulating valves and the fuel cell to circulate the fuel gas; and a plurality of ejector pumps disposed after the respective ejector pumps. A plurality of shut-off valves, the oxidizer electrode of the fuel cell, a water collecting means for collecting water contained in exhaust gas from the fuel electrode, and supplying the water collected by the water collecting means to the fuel cell. Do By controlling the opening degree of each pressure regulating valve in response to a supply means and a fuel cell output request from the outside, the combination of the opening degrees of the plurality of pressure regulating valves allows the fuel gas pressure required for the fuel cell output request to be adjusted. A fuel cell system comprising: control means that satisfies the entire range, and satisfies a fuel gas circulating flow rate in an entire range required by a fuel cell output request by a combination of circulating flow rates of a plurality of ejector pumps. 16. The small pressure regulating valve for regulating the pressure of the fuel gas when the supply of the fuel gas to the fuel cell is a small flow rate, and the supply of the fuel gas to the fuel cell. 16. The fuel cell system according to claim 15, wherein the fuel cell system is a large pressure regulating valve for adjusting the pressure of the fuel gas when the flow rate is large. 17. A small ejector pump for circulating surplus fuel gas from the fuel cell when the fuel gas is supplied at a small flow rate, the plurality of ejector pumps;
17. The fuel cell system according to claim 16, wherein the fuel cell system is a large-sized ejector pump for circulating surplus fuel gas from the fuel cell when the fuel gas is supplied at a large flow rate. 18. The pressure controllable range of the small pressure regulating valve is substantially equal to the fuel gas flow rate range which is the circulatable range of the small ejector pump. The pressure controllable range of the large pressure regulating valve and the large ejector 18. The fuel cell system according to claim 17, wherein the fuel gas flow rate ranges that can be circulated by the pump are substantially equal. 19. The control means includes means for shutting off a shut-off valve provided at a stage subsequent to the large-sized ejector pump within a range of a fuel gas flow rate in which the pressure regulation and the circulation amount can be adjusted by the small-sized pressure regulating valve and the small-sized ejector pump. Close and fully open the shut valve provided at the subsequent stage of the small ejector pump, control the pressure regulation and the circulation amount with the small pressure regulating valve and the small ejector pump, and adjust the large pressure regulating valve and the large ejector pump with the large pressure regulating valve and the large ejector pump. Within the fuel gas flow rate range where the pressure regulation and the circulation amount can be adjusted, the shut valve provided at the subsequent stage of the large ejector pump is fully opened,
19. The fuel cell system according to claim 18, wherein a shut-off valve provided at a stage subsequent to the small ejector pump is fully closed, and the large pressure regulating valve and the large ejector pump are controlled so as to regulate the pressure and the circulation amount. . 20. The control means according to claim 1, wherein said small pressure regulating valve and said small ejector pump are provided with a shutoff valve provided at a subsequent stage of said large ejector pump in a fuel gas flow rate range in which the pressure regulation and circulation amount can be adjusted. Close and fully open the shut valve provided at the subsequent stage of the small ejector pump, control the pressure regulation and the circulation amount with the small pressure regulating valve and the small ejector pump, and adjust the large pressure regulating valve and the large ejector pump with the large pressure regulating valve and the large ejector pump. Within the fuel gas flow rate range where the pressure regulation and the circulation amount can be adjusted, the shut valve provided at the subsequent stage of the large ejector pump is fully opened,
19. The fuel cell system according to claim 18, wherein a shut-off valve provided at a stage subsequent to the small ejector pump is fully closed, and the large pressure regulating valve and the large ejector pump are controlled so as to regulate the pressure and the circulation amount. .