JP2009117225A - Fuel cell system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To surely shut off supply of hydrogen gas even when abnormality occurs in a control part controlling supply of hydrogen gas. <P>SOLUTION: A fuel cell system is equipped with a fuel cell 2 generating power by electrochemical reaction of hydrogen gas and oxidative gas; a hydrogen gas supply passage 41 for supplying hydrogen gas from a hydrogen pump 40 to the fuel cell 2; a hydrogen sub-valve 43 and a hydrogen main valve 44 installed in the hydrogen gas supply passage 41 and shutting off or allowing supply of hydrogen gas to the fuel cell 2; a control part 5 controlling opening and closing of the hydrogen sub-valve 43 and the hydrogen main valve 44 and determining whether control of the hydrogen sub-valve 43 is possible or not; and a preliminary control part 6 closing the hydrogen main valve 33 when control of the hydrogen sub-valve 43 is determined to be impossible. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a fuel cell system.

In the fuel cell system, combustible fuel gas is consumed in the fuel cell. Therefore, it is necessary to give sufficient consideration to the handling of fuel gas in order to ensure safety. In the following Patent Document 1 or 2, in a fuel cell vehicle (FCHV; Fuel Cell Hybrid Vehicle) equipped with a fuel cell, when a vehicle collision is detected or when it is determined that there is a high possibility that the vehicle will collide, A technique for shutting off the supply of fuel gas is disclosed.
JP 2001-357863 A JP 2004-349110 A

  By the way, the supply of the fuel gas is controlled by opening and closing a control valve provided in the fuel supply channel. The opening and closing of the control valve is controlled by an ECU (Engine Control Unit) mounted on the vehicle. Therefore, if an abnormality occurs in the ECU while supplying fuel gas, it may be impossible to open and close the control valve. In such a case, the supply of fuel gas may be shut off. It becomes impossible.

  The present invention has been made to solve the above-mentioned problems caused by the prior art, and even when an abnormality occurs in the control means for controlling the supply of the fuel gas, the supply of the fuel gas is surely cut off. It is an object of the present invention to provide a fuel cell system that can be used.

  In order to solve the above-described problems, a fuel cell system according to the present invention includes a fuel cell that receives supply of a fuel gas and an oxidizing gas and generates electric power by an electrochemical reaction of the fuel gas and the oxidizing gas, A fuel supply channel for supplying the fuel cell from a supply source; a control valve provided in the fuel supply channel for blocking or permitting the supply of fuel gas to the fuel cell; and a first for controlling the opening and closing of the control valve The control means, the determination means for determining whether the control to the control valve by the first control means is possible, and the control means when the determination means determines that the control valve cannot be controlled. And a second control means for closing the valve.

  According to the present invention, an abnormality occurs in the first control means that controls the control valve that shuts off or allows the supply of the fuel gas to the fuel cell. When the control becomes impossible, the control valve can be closed by the second control means. That is, even when an abnormality occurs in the first control unit that controls the supply of the fuel gas, the supply of the fuel gas can be reliably shut off.

  The first control means and the second control means are housed in separate control units, and the control unit housing the second control means is more fireproof than the control unit housing the first control means. And impact resistance can be increased.

  In this way, for example, even when the control of the control valve by the first control means becomes impossible due to a collision or the like, the second control unit is housed in a control unit having high fire resistance and impact resistance. Since the control valve can be controlled by this control means, the possibility of shutting off the supply of fuel gas can be greatly increased even when an abnormality occurs in the first control means.

  According to the present invention, even if an abnormality occurs in the control means for controlling the supply of fuel gas, the supply of fuel gas can be reliably shut off.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of a fuel cell system according to the invention will be described with reference to the accompanying drawings. This embodiment demonstrates the case where the fuel cell system which concerns on this invention is used as a vehicle-mounted power generation system of a fuel cell vehicle (FCHV; Fuel Cell Hybrid Vehicle).

  The fuel cell system according to the present embodiment is provided separately from the control unit even when an abnormality occurs in the control unit that controls the supply of the fuel gas and the control unit cannot stop the supply of the fuel gas. The supply of fuel gas is surely cut off by the prepared preliminary control unit. Hereinafter, the configuration and operation of the fuel cell system having such characteristics will be described in detail.

  With reference to FIG. 1, the structure of the fuel cell system in this embodiment is demonstrated. FIG. 1 is a configuration diagram schematically illustrating a fuel cell system according to an embodiment.

  As shown in FIG. 1, a fuel cell system 1 includes a fuel cell 2 that generates electric power by an electrochemical reaction between an oxidizing gas that is a reactive gas and the fuel gas, and an oxidizing gas that supplies air as the oxidizing gas to the fuel cell 2. A piping system 3; a hydrogen gas piping system 4 for supplying hydrogen as fuel gas to the fuel cell 2; a control unit 5 for overall control of the entire system; and a preliminary control unit 6 having a part of the control unit 5; Have The fuel cell 2 and the hydrogen gas piping system 4 constitute a hydrogen gas supply mechanism.

  The fuel cell 2 is, for example, a polymer electrolyte fuel cell, and has a stack structure in which a large number of single cells are stacked. The single cell has an air electrode on one surface of an electrolyte composed of an ion exchange membrane, a fuel electrode on the other surface, and a structure having a pair of separators so as to sandwich the air electrode and the fuel electrode from both sides. It has become. In this case, hydrogen gas is supplied to the hydrogen gas flow path of one separator, oxidizing gas is supplied to the oxidizing gas flow path of the other separator, and electric power is generated by the chemical reaction of these reaction gases. Part of the direct-current power generated by the fuel cell 2 is stepped down by a DC / DC converter (not shown) and charged to a secondary battery (not shown) that is a battery.

  The oxidizing gas piping system 3 compresses air taken in through the filter 30 and sends out compressed air as oxidizing gas, and an air supply flow path 32 for supplying the oxidizing gas to the fuel cell 2. And an air discharge passage 33 for discharging the oxidizing off-gas discharged from the fuel cell 2. The air supply flow path 32 and the air discharge flow path 33 are provided with a humidifier 34 that humidifies the oxidizing gas pumped from the compressor 31 using the oxidizing off gas discharged from the fuel cell 2. The oxidizing off gas that has undergone moisture exchange or the like in the humidifier 34 is finally exhausted into the atmosphere outside the system as exhaust gas.

  The hydrogen gas piping system 4 includes a hydrogen tank 40 as a fuel supply source that stores high-pressure (for example, 70 MPa) hydrogen gas, and a fuel supply passage for supplying the hydrogen gas from the hydrogen tank 40 to the fuel cell 2. A hydrogen supply channel 41 and a circulation channel 42 for returning the hydrogen off-gas discharged from the fuel cell 2 to the hydrogen supply channel 41 are provided. The hydrogen tank 40 is an embodiment of the fuel supply source in the present invention. Instead of the hydrogen tank 40 in the present embodiment, for example, a reformer that reforms a hydrocarbon-based fuel into a hydrogen-rich fuel gas using water vapor, and a fuel gas reformed in the reformer with a high pressure A high-pressure gas tank that accumulates pressure in a state can be employed as a fuel supply source. A tank having a hydrogen storage alloy can also be employed as a fuel supply source.

  In the hydrogen supply channel 41, a hydrogen sub valve 43 and a hydrogen main valve 44 that block or allow the supply of hydrogen gas from the hydrogen tank 40, a regulator 45 that adjusts the pressure of the hydrogen gas to a preset secondary pressure, Is provided. The hydrogen sub valve 43 is a control valve provided on a flow path branched for each hydrogen tank 40 in the hydrogen supply flow path 41 when there are a plurality of hydrogen tanks 40, and the hydrogen main valve 44 is provided for each hydrogen tank 40. It is a control valve provided on the hydrogen supply flow path 41 where the branched flow paths merge.

  The circulation channel 42 is provided with a hydrogen pump 46 that pressurizes the hydrogen off-gas in the circulation channel 42 and sends it to the hydrogen supply channel 41 side. In addition, a discharge flow path 49 is connected to the circulation flow path 42 via a gas-liquid separator 47 and an exhaust drain valve 48. The gas-liquid separator 47 collects moisture from the hydrogen off gas. The exhaust / drain valve 48 discharges (purges) the moisture recovered by the gas-liquid separator 47 and the hydrogen off-gas containing impurities in the circulation passage 42 in accordance with a command from the control unit 5. The hydrogen off-gas discharged from the exhaust / drain valve 48 is diluted by the diluter 50 and merges with the oxidizing off-gas in the air discharge channel 33.

  The control unit 5 detects an operation amount of an acceleration operation member (accelerator or the like) provided in the fuel cell vehicle, and provides control information such as an acceleration request value (for example, a required power generation amount from a power consumption device such as a traction motor). In response, the operation of various devices in the system is controlled. In addition to the traction motor, the power consuming device includes, for example, an auxiliary device (for example, a motor for the compressor 31 and the hydrogen pump 46) necessary for operating the fuel cell 2, and various devices involved in traveling of the vehicle. These include actuators used in (transmissions, wheel control devices, steering devices, suspension devices, etc.), air conditioning devices (air conditioners) for passenger spaces, lighting, audio, and the like.

  The control unit 5 (first control means) controls opening and closing of the hydrogen sub valve 43 and the hydrogen main valve 44.

  The control unit 5 (determination means) determines whether or not the control to the hydrogen sub-valve 43 is possible. When it is determined that the control to the hydrogen sub-valve 43 is impossible, the control unit 5 (determination means) A control request signal for requesting control of the main valve 44 is transmitted. As a method for determining whether or not the control to the hydrogen sub-valve 43 is possible, for example, the following method can be employed. When the control unit 5 transmits a valve closing instruction signal to the hydrogen sub-valve 43 and cannot receive a valve closing completion signal from the hydrogen sub-valve 43 as a response thereto, it is determined that control to the hydrogen sub-valve 43 is impossible. To do.

  Here, the control unit 5 physically includes, for example, a CPU, a ROM and an HDD that store control programs and control data processed by the CPU, and a RAM that is mainly used as various work areas for control processing. And an input / output interface, and these elements are housed in an ECU which is a control unit. Each element that physically configures the control unit 5 is connected to each other via a bus. The input / output interface is connected to various sensors such as a pressure sensor, a current sensor, and a voltage sensor, and a communication module with a CPU of the preliminary control unit 6 described later, and includes a compressor 31, a hydrogen sub valve 43, and a hydrogen main valve 44. Various drivers for driving the hydrogen pump 46 and the exhaust / drain valve 48 are connected.

  The CPU of the control unit 5 receives the detection results of the pressure sensor, current sensor, and voltage sensor via the input / output interface according to the control program stored in the ROM, and processes them using various data in the RAM. Thus, the hydrogen gas cutoff processing of the fuel cell system 1 is controlled. Further, the CPU controls the entire fuel cell system 1 by outputting control signals to various drivers and the CPU of the preliminary control unit 6 via the input / output interface.

  The preliminary control unit 6 (second control means) closes the hydrogen main valve 44 when receiving the control request signal transmitted from the control unit 5.

  Here, the preliminary control unit 6 is physically used as, for example, a CPU, a ROM or HDD for storing control programs and control data processed by the CPU, and various work areas mainly for control processing. RAM, input / output interface, and auxiliary battery, these elements are housed in a control unit integrated with fireproof and shock resistant equipment (eg hydrogen leak detector, flame detector). The The elements that physically configure the spare control unit 6 are connected to each other via a bus. A communication module with the CPU of the control unit 5 is connected to the input / output interface, and various drivers for driving the hydrogen main valve 44 and the like are connected.

  The CPU of the preliminary control unit 6 receives a control request signal from the CPU of the control unit 5 through the input / output interface according to the control program stored in the ROM, and outputs the control signal to various drivers through the input / output interface. As a result, the hydrogen main valve 44 and the like are controlled. Further, the CPU of the preliminary control unit 6 drives the hydrogen main valve 44 using the auxiliary battery when the main battery mounted on the vehicle becomes unable to output.

  Next, the hydrogen gas cutoff processing of the fuel cell system in the embodiment will be described using the flowchart shown in FIG.

  First, the control unit 5 determines whether or not the hydrogen sub valve 43 is controllable (step S1). If this determination is YES (step S1; YES), the process of step S1 is repeated.

  On the other hand, when it is determined in step S1 that the hydrogen sub valve 43 is uncontrollable (step S1; NO), the control unit 5 sends a control request signal for requesting to control the hydrogen main valve 44 to the preliminary control unit. 6 (step S2). The preliminary control unit 6 that has received the control request signal closes the hydrogen main valve 44 (step S3).

  As described above, according to the fuel cell system 1 in the embodiment, an abnormality occurs in the control unit 5 that controls the hydrogen sub valve 43 and the hydrogen main valve 44 that block or allow the supply of the hydrogen gas to the fuel cell 2. When the control to the hydrogen sub valve 43 executed by the control unit 5 becomes impossible, the preliminary control unit 6 can close the hydrogen sub valve 43. That is, even when an abnormality occurs in the control unit 5 that controls the supply of hydrogen gas, the supply of hydrogen gas can be reliably shut off, and safety can be ensured.

  Each element that physically configures the control unit 5 is housed in the ECU, and each element that physically configures the preliminary control unit 6 is a hydrogen leak detector or flame detector having high fire resistance and impact resistance. For example, when the control of the hydrogen sub-valve 43 becomes impossible due to a short circuit in the wire harness connecting between the ECU and the hydrogen sub-valve 43 due to a collision or the like. Even so, the hydrogen main valve 44 can be closed by a control unit that has a high possibility of surviving at the time of collision by being integrated with a device having high fire resistance and impact resistance. Therefore, even if an abnormality occurs in the ECU, the possibility of shutting off the supply of hydrogen gas can be greatly increased.

  In the above-described embodiment, the description has been made using the fact that the control to the hydrogen sub-valve 43 becomes impossible as a requirement when the control unit 5 transmits a control request signal to the preliminary control unit 6. It is not limited. For example, a control request signal may be transmitted when control of the hydrogen main valve 44 in addition to the hydrogen sub-valve 43 is impossible. That is, it is only necessary that the control request signal can be transmitted when the control unit 5 cannot stop the supply of the hydrogen gas to the fuel cell 2.

  In the above-described embodiment, the hydrogen main valve 44 is described as the target to be closed by the preliminary control unit 6, but is not limited thereto, and the hydrogen valve provided on the hydrogen supply channel 41 is not limited thereto. I just need it. That is, it suffices if the supply of hydrogen gas to the fuel cell 2 can be shut off when the control unit 5 becomes unable to control the hydrogen valve. Therefore, for example, all the hydrogen sub valves 43 may be closed. However, the closer the position of the hydrogen valve to be closed to the fuel cell 2, the longer the hydrogen supply channel 41 between the hydrogen tank 40 and the hydrogen valve, and thus the more hydrogen remaining in the hydrogen supply channel 41. Gas can be sealed.

  Further, in the above-described embodiment, each element that physically configures the preliminary control unit 6 is housed in a control unit that is integrated with a hydrogen leak detector and a flame detector having high fire resistance and impact resistance. However, it is not limited to this. For example, each element that physically configures the preliminary control unit 6 may be housed in a control unit that is separate from the ECU and has higher fire resistance and impact resistance than the ECU.

  Further, in each of the above-described embodiments, the case where the fuel cell system according to the present invention is mounted on a fuel cell vehicle has been described. However, various mobile bodies (robots, ships, aircrafts, etc.) other than the fuel cell vehicle are also described. The fuel cell system according to the present invention can be applied. Moreover, the fuel cell system according to the present invention can also be applied to a stationary power generation system used as a power generation facility for buildings (houses, buildings, etc.).

It is a lineblock diagram showing typically the fuel cell system in an embodiment. It is a flowchart for demonstrating the hydrogen gas interruption | blocking process of the fuel cell system in embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Fuel cell system, 2 ... Fuel cell, 3 ... Oxidation gas piping system, 4 ... Hydrogen gas piping system, 5 ... Control part, 6 ... Preliminary control part, 30 ... Filter, 31 ... Compressor, 32 ... Air supply flow path , 33 ... Air discharge flow path, 34 ... Humidifier, 40 ... Hydrogen tank, 41 ... Hydrogen supply flow path, 42 ... Circulation flow path, 43 ... Hydrogen sub-valve, 44 ... Hydrogen main valve, 45 ... Regulator, 46 ... Hydrogen pump 47 ... Gas-liquid separator, 48 ... Exhaust drain valve, 49 ... Discharge flow path, 50 ... Diluter.

Claims (2)

A fuel cell that receives supply of the fuel gas and the oxidizing gas and generates electric power by an electrochemical reaction of the fuel gas and the oxidizing gas;
A fuel supply flow path for supplying the fuel gas from a fuel supply source to the fuel cell;
A control valve provided in the fuel supply flow path, for blocking or allowing the supply of the fuel gas to the fuel cell;
First control means for controlling opening and closing of the control valve;
Determination means for determining whether or not control to the control valve by the first control means is possible;
Second control means for closing the control valve when the determination means determines that control of the control valve is impossible;
A fuel cell system comprising:   The first control means and the second control means are each housed in separate control units, and the control unit that houses the second control means is more than the control unit that houses the first control means. The fuel cell system according to claim 1, wherein the fuel cell system has high fire resistance and impact resistance.

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