JP2005339847A - Fuel cell system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell system with improved system efficiency by the use of a switching valve satisfying the conditions of low-pressure loss, large current volume, high response, high closing property, compactness, and low drive power, in a good balance. <P>SOLUTION: The fuel cell system (10) is provided with a fuel gas storage device (20) for storing fuel gas, a fuel gas supply path (31) connecting the fuel cell with the fuel gas storage device (20), and a switching valve (43) fitted on the fuel gas supply path (31)for adjusting an aperture of the fuel gas supply path (31). The switching valve (43) at least a differential pressure valve driven for switching with the use of fuel gas discharged from the fuel gas storage device (20). Since the differential pressure valve is controlled for switching with pressure of fuel gas, the valve can be switched without much operating power, so that conditions of low-pressure loss, large current volume, high response, high closing property, compactness, and low drive power can be satisfied with a good balance. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a fuel cell system having an on-off valve in a reaction gas system, and more particularly to an improved technique for improving system efficiency.

2. Description of the Related Art As a power supply device for a fuel cell vehicle or the like, a fuel cell system that can directly extract chemical energy resulting from a redox reaction between a fuel gas and an oxidizing gas as electric energy is used. In this type of fuel cell system, for example, as disclosed in Japanese Patent Application Laid-Open No. 2003-178777, various shutoff valves are used in the gas piping system (fuel gas system, oxidizing gas system). Many of them are electromagnetic shut-off valves. The shut-off valve installed in the gas piping system is balanced by low pressure loss, large flow rate, high response, high deadlines, small size, and low driving power (low operating power) in order to increase system efficiency. Well requested.
JP 2003-178777 A

  However, in order to satisfy the flow characteristics of low pressure loss and large flow rate, it is necessary to secure a large valve flow path. If the valve flow path is made larger, the pressure of the fluid applied to the opening / closing portion of the valve increases, so that the driving force for opening / closing the valve increases. A large driving force is also required to improve the valve shut-off and responsiveness. However, increasing the valve driving force increases auxiliary power, resulting in a deterioration in fuel consumption and a reduction in system efficiency.

  For example, when an electric motor is used to open and close the valve, it is difficult to reduce the size and good responsiveness cannot be obtained. When a direct acting solenoid valve that opens and closes a valve with an electromagnet is used, the valve becomes large in order to ensure a low pressure loss and a large flow rate, and the driving force also increases. Although the pilot type solenoid valve is small, if the differential pressure before and after the operation is small, good deadlines and responsiveness cannot be obtained, and further backflow cannot be prevented. Although the air-driven valve is small, an air compressor for supplying a signal pressure to the air-driven valve is required, which increases the size of the device and increases auxiliary power, which is not preferable.

  Therefore, the present invention provides a fuel cell system that can improve system efficiency by using an on-off valve that satisfies the conditions of low pressure loss, large flow rate, high response, high deadline, small size, and low driving force in a well-balanced manner. The challenge is to propose.

  In order to solve the above problems, a fuel cell system according to the present invention is provided on a reaction gas supply path for storing a reaction gas, a reaction gas supply path for connecting the fuel cell and the reaction gas supply source, and a reaction gas supply path. An open / close valve that adjusts the opening of the reaction gas supply path, and the open / close valve is a differential pressure valve that is driven to open and close using at least the pressure of the reaction gas released from the reaction gas supply source. Since the differential pressure valve is controlled to open and close by the pressure of the reaction gas, it is possible to open and close the valve without requiring large operating power, and low pressure loss, large flow rate, high response, high shut-off, small size, low drive The power requirements can be met in a well-balanced manner.

  In order to supply the driving gas to the differential pressure valve, for example, a bypass flow path that branches from the reaction gas supply path and communicates with the signal pressure chamber of the differential pressure valve is provided, and the pressure of the reaction gas that propagates through the bypass flow path A configuration in which the differential pressure valve is driven to open and close is preferable. With this configuration, the pressure of the reaction gas can be propagated to the differential pressure valve as a signal pressure.

  Here, a regulator for reducing the pressure of the reaction gas is provided in the reaction gas supply path, and the bypass flow path is preferably branched from the reaction gas supply path upstream of the regulator. By branching the bypass channel from the upstream side of the regulator of the reaction gas supply path, the driving gas can be adjusted to a high pressure, and the differential pressure valve can be controlled to open and close using the differential pressure with the reaction gas supply path.

  As the reaction gas supply source, for example, a high-pressure gas tank that stores the reaction gas in a high-pressure state is suitable. By using a high-pressure reaction gas as a driving gas for the differential pressure valve, the differential pressure valve can be controlled to open and close.

  According to the present invention, since the differential pressure valve is controlled to open and close by the pressure of the reaction gas, the valve can be opened and closed without requiring a large operating power, and low pressure loss, large flow rate, high response, and high deadline can be achieved. Performance, small size, and low driving force can be satisfied in a well-balanced manner.

  FIG. 1 is a system configuration diagram centering on a fuel gas system of a fuel cell system 10 of the present embodiment. The fuel gas system of the system mainly includes a fuel storage device (reactive gas supply source) 20 for storing fuel gas (reactive gas), and the fuel gas stored in the fuel storage device 20 to a fuel cell (cell stack). A fuel gas supply path (reaction gas supply path) 31 for supply, a differential pressure valve 43 that shuts off the fuel gas flowing through the fuel gas supply path 31, and a signal pressure chamber of the differential pressure valve 43 branched from the fuel gas supply path 31 A bypass flow path (branch flow path or detour flow path) 32 communicating with is provided. The differential pressure valve 43 functions as an on-off valve or a shut-off valve. The fuel storage device 20 is a device for compressing and storing the fuel gas at a high pressure. For example, a high-pressure hydrogen tank (high-pressure gas tank) that fills the fuel gas at a pressure of about 300 to 700 atm is suitable. The fuel gas supply path 31 has an intermediate pressure regulator (intermediate pressure reducing valve) 41 for reducing the fuel gas compressed to a high pressure to an intermediate pressure (intermediate pressure), and further lowering the fuel gas reduced to the intermediate pressure. A low-pressure regulator (low-pressure pressure reducing valve) 42 for reducing the pressure to (normal operating pressure) and the above-described differential pressure valve 43 are arranged in order from upstream to downstream. For convenience of explanation, a flow path upstream of the intermediate pressure regulator 41 in the fuel gas supply path 31 is 31 a, a flow path between the intermediate pressure regulator 41 and the low pressure regulator 42 is 31 b, and between the low pressure regulator 42 and the differential pressure valve 43. The flow path is 31c, the flow path on the downstream side of the differential pressure valve 43 is 31d, and the gas pressures of the flow paths 31a to 31d are P1 to P4.

  As shown in FIG. 2, in the differential pressure valve 43, the internal space of the body 71 is defined by upper and lower internal spaces by a diaphragm 72, one of which is a signal pressure chamber 73 and the other is a fuel gas supply path 31. The signal pressure chamber 73 is a sealed space in which an introduction hole 83 for introducing the pressure of the fuel gas (driving gas) propagated from the bypass passage 32 is formed. The fuel gas supply path 31 is a gas flow path communicating with an inlet port 81 and an outlet port 82 formed in the body 71, and a valve seat 75 for seating the valve body 74 is formed in the flow path. The inlet port 81 communicates with the fuel gas passage 31c, and the outlet port 82 communicates with the fuel gas passage 31d. When the valve body 74 is seated (closed) on the valve seat 75, the fuel gas supply path 31 is shut off, and when the valve body 74 is separated (opened) from the valve seat 75, the fuel gas supply path 31 is in a through state. Become. The valve body 74 is urged in a direction to be pressed against the valve seat 75 by springs 76 and 77. When the pressure (signal pressure) of the fuel gas introduced into the signal pressure chamber 73 is low, the valve element 74 cannot be pushed up in the direction away from the valve seat 75 against the urging force of the springs 76 and 77. Therefore, the differential pressure valve 43 is closed. On the other hand, when the pressure of the fuel gas introduced into the signal pressure chamber 73 is high, the valve element 74 can be separated from the valve seat 75 against the urging force of the springs 76 and 77, so that the differential pressure valve 43 is Open the valve. Such a differential pressure valve 43 is preferably configured as a low pressure loss valve by ensuring a large fuel gas passage area. Further, the differential pressure valve 43 may be a linear valve that adjusts the opening degree of the fuel gas supply passage 31 between “fully closed” and “fully opened” to the target opening degree. ) / A two-position on-off valve that can be switched to a two-position (fully closed).

  On the other hand, the bypass passage 32 is controlled to be opened and closed by a regulator (pressure reducing valve) 44 that reduces the driving gas branched from the fuel gas supply passage 31 and supplied to the differential pressure valve 43, and a control unit (ECU) 50. Each of the three-port solenoid valves 45 is disposed in order from upstream to downstream. For convenience of explanation, among the bypass flow paths 32, the flow path upstream of the regulator 44 is 32a, the flow path between the regulator 44 and the 3-port solenoid valve 45 is 32b, and the flow between the 3-port solenoid valve 45 and the differential pressure valve 43 is flow. Let the road be 32c. The three-port solenoid valve 45 includes ports A1 to A3. The port A1 is connected to the bypass passage 32b, the port A2 is connected to the bypass passage 32c, and the port A3 is connected to the fuel gas supply passage 31b via the driving gas exhaust passage 33. And communicate with each other. The driving gas exhaust passage 33 is provided with a check valve 46 for preventing the backflow of the driving gas exhausted from the bypass flow path 32 to the fuel gas supply path 31. Here, let the signal pressure of the bypass flow path 32b, the bypass flow path 32c, and the driving gas exhaust passage 33 be P5 to P7. When the signal pressure P6 supplied to the signal pressure chamber of the differential pressure valve 43 becomes high, the drive gas pushes the valve against the urging force of the spring in the signal pressure chamber, thereby opening the differential pressure valve 43. When the signal pressure P6 becomes low, the spring in the signal pressure chamber closes the valve against the driving gas, thereby closing the differential pressure valve 43. In order to control the opening / closing of the differential pressure valve 43 by adjusting the signal pressure P6 in two stages of high pressure and low pressure, the pressure is always adjusted so that P5 (high pressure)> P2 (low pressure). In this example, by providing the branch point 60 of the fuel gas supply path 31 and the bypass flow path 32 on the upstream side of the intermediate pressure regulator 41, the primary pressures of the regulators 41 and 44 are set to be the same. By adjusting the pressure regulation value, P5> P2 is set.

  The control unit 50 is a system controller that controls the operating state of the fuel cell, and controls the opening and closing of the differential pressure valve 43 through the opening and closing control of the ports A1 to A3 of the three-port solenoid valve 45, thereby connecting or blocking the fuel gas supply path 31. . For example, when the ports A1 and A2 are opened and the port A3 is closed, the bypass flow path 32b and the bypass flow path 32c communicate with each other, so that the gas pressures of both are equal, and P1> P5 = P6> P7> P2 > P3> P4. Since the signal pressure P6 supplied to the differential pressure valve 43 becomes equal to P5 (high pressure), the differential pressure valve 43 is opened. On the other hand, when the port A1 is closed and the ports A2 and A3 are opened, the bypass passage 32c and the fuel gas supply passage 31b communicate with each other via the driving gas exhaust passage 33, so that the gas pressures of both are equal. , P1> P5> P6 = P7 = P2> P3> P4. Since the signal pressure P6 supplied to the differential pressure valve 43 becomes equal to P2 (low pressure), the differential pressure valve 43 is closed.

  According to the present embodiment, by using the gas pressure of the fuel gas as the signal pressure P6 of the differential pressure valve 43, the valve can be opened and closed with a small driving force. Further, since the driving gas used for the valve operation is used as fuel gas, there is no waste of fuel. Furthermore, since a large flow path area of the differential pressure valve 43 can be secured, the pressure loss is low, and the differential pressure valve 43 is controlled to be opened and closed by the pressure of the fuel gas branched from the fuel gas supply path 31, so that the closing performance is excellent. ing. As described above, the differential pressure valve 43 functions as an on-off valve (or shut-off valve) that achieves a good balance of low pressure loss, large flow rate, high response, high shut-off, small size, and low driving force.

  The differential pressure valve 43 may be used as an on-off valve (or shut-off valve) of the fuel gas system, for example, as an anode-side stack inlet valve or stack outlet valve, or a hydrogen circulation system hydrogen exhaust valve or drain valve. It is also possible to use it in combination with these valves. In the above description, the case where the differential pressure valve 43 is used as an on-off valve (or shut-off valve) of the fuel gas system is exemplified. However, the present invention is not limited to this, and for example, the differential pressure valve 43 is used as the oxidizing gas system. It may be used as a shutoff valve, a cathode side stack inlet valve or stack outlet valve, or an oxidant gas system drain valve, and may be used in combination with these valves. That is, the differential pressure valve 43 described above can be applied to all the valves of the fuel cell system 10.

  Further, the configuration is not necessarily limited to the above-described configuration as long as the signal pressure P6 of the differential pressure valve 43 can be adjusted in two stages of high pressure and low pressure. For example, it is not essential to connect the port A3 of the three-port solenoid valve 45 to the fuel gas supply path 31b. For example, the port A3 communicates with another device such as a sub tank (which needs to be lower in pressure than the pressure P5). You may comprise.

It is a block diagram of the fuel cell system of this embodiment. It is sectional drawing of a differential pressure valve.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Fuel cell system 20 ... Fuel storage device 31 ... Fuel gas supply path 32 ... Bypass flow path 33 ... Drive gas exhaust passage 41 ... Medium pressure regulator 42 ... Low pressure regulator 43 ... Differential pressure valve 44 ... Regulator 45 ... Three port solenoid valve 50 ... Control unit 60 ... Branching point

Claims (4)

  A reaction gas supply source for storing the reaction gas, a reaction gas supply path connecting the fuel cell and the reaction gas supply source, and an on-off valve provided on the reaction gas supply path for adjusting the opening of the reaction gas supply path; And the on-off valve is a differential pressure valve that is opened / closed using at least the pressure of the reaction gas discharged from the reaction gas supply source.   2. The fuel cell system according to claim 1, wherein the differential pressure valve is driven to open and close by the pressure of a reactive gas that branches from the reactive gas supply passage and propagates through a bypass passage that communicates with a signal pressure chamber of the differential pressure valve. A fuel cell system.   3. The fuel cell system according to claim 2, wherein a regulator for reducing a pressure of the reaction gas is disposed in the reaction gas supply path, and the bypass flow path is located upstream of the regulator. A fuel cell system branched from the reaction gas supply path. 4. The fuel cell system according to claim 1, wherein the reaction gas supply source is a high-pressure gas tank that stores the reaction gas in a high-pressure state. 5.

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