JP2009021025A - Fuel cell system and mobile unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell system which can suppress differential pressure between electrodes even in the case that a variation amount in the supply pressure of a fuel gas becomes large. <P>SOLUTION: The fuel cell system 1 is provided with a fuel cell 10 having a fuel electrode and an oxidation electrode, an injector 35 which adjusts the supply pressure of the fuel gas supplied to the fuel electrode, and a pressure regulating valve 26 which adjusts the supply pressure of an oxidation gas supplied to the oxidation electrode. When the variation amount in the supply pressure of the fuel gas is determined to become large, the supply pressure of the fuel gas is adjusted by the injector 35 so that differential pressure between the electrodes of the fuel electrode and the oxidation electrode may be maintained within a prescribed range based on the supplied pressure of the fuel gas and the supply pressure of the oxidation gas. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a fuel cell system and a moving body, and more particularly to a technique for controlling a gas supply pressure to a fuel cell.

  In recent years, a fuel electrode and an oxidation electrode are provided on both sides of a solid polymer electrolyte membrane (hereinafter referred to as an electrolyte membrane), and a fuel gas such as hydrogen gas is supplied to the fuel electrode side, while air or the like is provided on the oxidation electrode side. Development of a fuel cell system including a fuel cell capable of supplying an oxidizing gas and directly taking out chemical energy resulting from an oxidation-reduction reaction between the fuel gas and the oxidizing gas as electric energy is in progress.

  In this type of fuel cell system, the pressure difference between the fuel gas supply pressure on the fuel electrode side and the oxidation gas supply pressure on the oxidation electrode side (hereinafter referred to as the difference between the electrodes) is used to prevent damage to the electrolyte membrane and prolong the service life. Pressure) must be controlled below a predetermined value. For this reason, for example, Patent Document 1 proposes a fuel cell power generator that keeps the differential pressure between the electrodes within a necessary range by controlling the control valve so that the differential pressure between the fuel electrode outlet and the air electrode outlet becomes constant. Have

JP2001-15141

  However, in this fuel cell power generator, since the control valve is used, the response is poor, and the pressure cannot be finely adjusted according to the state of the system. Therefore, for example, when the supply pressure of the fuel gas changes greatly, such as at the time of starting the system, the pressure regulation by the control valve cannot follow the change in the supply pressure, and the pressure difference between the electrodes temporarily There is a risk of becoming larger

  Therefore, the present invention has been made in view of the above-described problems of the prior art, and its purpose is to keep the pressure difference between the electrodes low even when the amount of change in the supply pressure of the fuel gas becomes large. It is an object of the present invention to provide a fuel cell system and a moving body that can be used.

  In the present invention, the following means are adopted in order to solve the above-mentioned problems. That is, the present invention provides a fuel cell having a fuel electrode and an oxidation electrode, an injector for adjusting a supply pressure of fuel gas supplied to the fuel electrode, and a control for adjusting a supply pressure of oxidation gas supplied to the oxidation electrode. A fuel valve system, and when it is determined that the amount of change in the supply pressure of the fuel gas is large, the fuel gas system is based on the supply pressure of the fuel gas and the supply pressure of the oxidizing gas. The fuel gas supply pressure is adjusted by the injector so that the differential pressure between the electrode and the oxidation electrode is maintained within a predetermined range.

  According to this configuration, the amount of change in the supply pressure of the fuel gas is determined, and the supply pressure of the fuel gas is adjusted by using the injector. Due to the pressure response, the supply pressure of the fuel gas can be quickly changed with high accuracy. Also, the pressure control response differs between the injector that adjusts the fuel gas supply pressure and the pressure control valve that adjusts the supply pressure of the oxidizing gas, and this difference in response is particularly large when the amount of change in the fuel gas supply pressure is large. Even if it appears in the form of a temporary increase in the differential pressure between the electrodes (because the pressure adjustment speeds of the pressure adjustment valve and the injector are different), the fuel gas supply pressure and the oxidant gas supply pressure must be detected. Since the injector can perform pressure regulation with high accuracy and speed, it is possible to prevent a temporary increase in the differential pressure between the electrodes at the time of starting the system due to the difference in pressure regulation response between the injector and the pressure regulation valve.

  The injector in this specification typically has a gas state (flow rate, pressure, temperature, molar concentration) by driving the valve body directly with a predetermined driving cycle with an electromagnetic driving force and separating it from the valve seat. It is configured as an electromagnetically driven on-off valve capable of adjusting the gas state represented by the above and the like, and particularly including at least one of the gas flow rate and the gas pressure.

  Further, the fuel cell system is configured such that the amount of change in the supply pressure of the fuel gas is determined to be large when the system is started or when the difference in gas pressure between the upstream side and the downstream side of the injector is greater than a predetermined value. May be.

  According to this configuration, when the system is started, or when the difference in gas pressure between the upstream side and the downstream side of the injector is greater than a predetermined value, the amount of change in the fuel gas is the previous stage, so In addition, it is possible to determine the case where the amount of change in the fuel gas supply pressure increases without measuring the amount of change in the fuel gas supply pressure.

  In this specification, “at the time of system startup” indicates a series of steps for starting the operation of the stopped fuel cell system, and typically, from the stopped fuel supply source to the fuel supply path. A step in which the supply of the fuel gas is started.

  In the fuel cell system, the injector adjusts a supply pressure of the fuel gas by controlling an operation of a valve body by an electromagnetic driving force, and the pressure regulating valve includes a primary pressure, a secondary pressure, and an external pressure. The supply pressure of the oxidizing gas may be adjusted by operating the valve body in accordance with at least one of the fluctuations.

  According to this configuration, the injector in which the operation of the valve body is controlled by an electromagnetic driving force, and the pressure regulating valve in which the valve body operates in accordance with at least one variation of the primary pressure, the secondary pressure, and the external pressure, However, the pressure of the injector and the pressure-regulating valve can be adjusted with high accuracy and prompt pressure adjustment by detecting the supply pressure of the fuel gas and the supply pressure of the oxidizing gas as described above. It is possible to prevent a temporary increase in the differential pressure between the electrodes at the time of starting the system due to the difference in response.

  Here, the pressure regulating valve typically maintains a primary side fluid pressure at a certain constant pressure, so that a back pressure valve that discharges fluid in response to a change in the primary side pressure or a secondary side fluid pressure is changed to the primary side. It is assumed that a pressure reducing valve that maintains a certain pressure lower than the fluid pressure is included.

  Moreover, the mobile body of this invention is equipped with the said fuel cell system.

  According to this configuration, even when the amount of change in the supply pressure of the fuel gas becomes large, the fuel cell system that suppresses the differential pressure between the electrodes is provided. It is possible to provide a moving body that can keep the load low.

  ADVANTAGE OF THE INVENTION According to this invention, even if it is a case where the variation | change_quantity of the supply pressure of fuel gas becomes large, the fuel cell system and moving body which can hold down the pressure difference between electrodes can be provided.

Hereinafter, a fuel cell system according to an embodiment of the present invention will be described in the following order with reference to the drawings. In the present embodiment, an example in which the present invention is applied to an on-vehicle power generation system of a fuel cell vehicle (moving body) will be described. In addition, in each drawing, the same code | symbol is attached | subjected to the same components.
1. 1. Overall configuration of fuel cell system according to an embodiment of the present invention 2. Method for controlling pressure difference between electrodes of fuel cell system according to an embodiment of the present invention Modification of fuel cell system according to an embodiment of the present invention

1. Overall Configuration of Fuel Cell System According to an Embodiment of the Present Invention First, an overall configuration of a fuel cell system 1 according to an embodiment of the present invention will be described with reference to FIG. As shown in FIG. 1, the fuel cell system 1 according to the present embodiment includes a fuel cell 10 that generates electric power upon receiving a supply of reaction gas (oxidation gas and fuel gas), and the fuel cell 10 has an oxidant gas. An oxidizing gas piping system 2 for supplying the air, a hydrogen gas piping system 3 for supplying hydrogen gas as a fuel gas to the fuel cell 10, a control device 4 for integrated control of the entire system, and the like.

  The fuel cell 10 has a stack structure in which a required number of unit cells that generate power upon receiving a reaction gas are stacked. Although not shown in the figure, each unit cell is composed of an electrolyte membrane made of an ion exchange membrane, and a pair of hydrogen electrode (fuel electrode) and oxygen electrode (oxidation electrode) sandwiching the electrolyte membrane from both sides.

  An oxidizing gas having a predetermined pressure is supplied to the oxygen electrode by the oxidizing gas piping system 2, and a hydrogen gas having a predetermined pressure is supplied to the hydrogen electrode by the hydrogen gas piping system 3. As will be described later, the pressure difference between the oxygen gas on the oxygen electrode side and the hydrogen gas on the hydrogen electrode side (hereinafter referred to as the inter-electrode differential pressure) is always a predetermined value so as not to become excessive regardless of the power generation amount of the fuel cell 10. Set to:

  The electric power generated by the fuel cell 10 is supplied to a PCU (Power Control Unit) 11. The PCU 11 includes an inverter, a DC-DC converter, and the like that are disposed between the fuel cell 10 and the traction motor 12. Further, the fuel cell 10 is provided with a current sensor 13 for detecting a current during power generation.

  The oxidizing gas piping system 2 includes an oxidizing gas supply channel 21 that supplies the oxidizing gas (air) humidified by the humidifier 20 to the fuel cell 10, and an oxidation that guides the oxidizing off-gas discharged from the fuel cell 10 to the humidifier 20. A gas discharge channel 22 and an exhaust channel 23 for introducing the oxidizing off gas from the humidifier 21 to the outside are provided. The oxidizing gas supply channel 21 is provided with a compressor 24 that takes in air in the atmosphere and pumps it to the humidifier 20. The oxidant gas discharge channel 22 has an oxygen electrode side pressure sensor 25 for detecting the pressure of the oxidant gas in the fuel cell 10 and a fuel cell by adjusting the flow rate of the oxidant off-gas according to the change in the primary pressure. A back pressure valve 26 for adjusting the pressure of the oxidant gas within 10 is disposed.

  The hydrogen gas piping system 3 includes a hydrogen tank 30 as a fuel supply source storing high-pressure hydrogen gas, a hydrogen supply passage 31 for supplying the hydrogen gas in the hydrogen tank 30 to the fuel cell 10, and the fuel cell 10. A circulation flow path 32 for returning the discharged hydrogen off-gas to the hydrogen supply flow path 31. Instead of the hydrogen tank 30, a reformer that generates a hydrogen-rich reformed gas from a hydrocarbon-based fuel, a high-pressure gas tank that stores the reformed gas generated by the reformer in a high-pressure state, and Can also be employed as a fuel supply source. A tank having a hydrogen storage alloy may be employed as a fuel supply source.

  The hydrogen supply flow path 31 is provided with a shutoff valve 33 that shuts off or allows the supply of hydrogen gas from the hydrogen tank 30, a regulator 34 that adjusts the pressure of the hydrogen gas, and an injector 35. Further, an upstream side pressure sensor 41 and a temperature sensor 42 for detecting the pressure and temperature of hydrogen gas in the hydrogen supply flow path 31 are provided on the upstream side of the injector 35. Further, on the downstream side of the injector 35 and upstream of the junction A1 between the hydrogen supply flow path 31 and the circulation flow path 32, a hydrogen electrode side pressure sensor for detecting the pressure of hydrogen gas in the fuel cell 10 is provided. 43 is provided.

  The regulator 34 is a device that regulates the upstream pressure (primary pressure) to a preset secondary pressure. In the present embodiment, a mechanical pressure reducing valve that reduces the primary pressure is employed as the regulator 34. The mechanical pressure reducing valve has a structure in which a back pressure chamber and a pressure adjusting chamber are formed with a diaphragm therebetween, and the primary pressure is reduced to a predetermined pressure in the pressure adjusting chamber by the back pressure in the back pressure chamber. Thus, a publicly known configuration for the secondary pressure can be employed. In the present embodiment, as shown in FIG. 1, the upstream pressure of the injector 35 can be effectively reduced by arranging two regulators 34 on the upstream side of the injector 35. For this reason, the design freedom of the mechanical structure (a valve body, a housing, a flow path, a drive device, etc.) of the injector 35 can be increased. In addition, since the upstream pressure of the injector 35 can be reduced, it is possible to prevent the valve body of the injector 35 from becoming difficult to move due to an increase in the differential pressure between the upstream pressure and the downstream pressure of the injector 35. be able to. Accordingly, it is possible to widen the adjustable pressure width of the downstream pressure of the injector 35 and to suppress a decrease in responsiveness of the injector 35.

  The injector 35 is an electromagnetically driven on-off valve capable of adjusting the gas flow rate and gas pressure by driving the valve body directly with a predetermined driving cycle with an electromagnetic driving force and separating it from the valve seat. The injector 35 includes a valve seat having an injection hole for injecting gaseous fuel such as hydrogen gas, a nozzle body for supplying and guiding the gaseous fuel to the injection hole, and an axial direction (gas flow direction) with respect to the nozzle body. And a valve body that is movably accommodated and opens and closes the injection hole. In this embodiment, the valve body of the injector 35 is driven by a solenoid that is an electromagnetic drive device, and the opening area of the injection hole is made two or more stages by turning on and off the pulsed excitation current supplied to the solenoid. It can be switched. The gas injection time and gas injection timing of the injector 35 are controlled by a control signal output from the control device 4, whereby the flow rate and pressure of hydrogen gas are controlled with high accuracy. The injector 35 directly opens and closes the valve body and the valve seat with an electromagnetic driving force. Since the driving cycle can be controlled up to a highly responsive region, the injector 35 has high responsiveness.

  Injector 35 changes the opening area (opening) and the opening time of the valve body provided in the gas flow path of injector 35 in order to supply the required gas flow rate downstream thereof, thereby reducing the downstream flow rate. The gas flow rate (or hydrogen molar concentration) supplied to the side (fuel cell 10 side) is adjusted. The gas flow rate is adjusted by opening and closing the valve body of the injector 35, and the pressure adjustment amount (reduced pressure amount) of the upstream gas pressure of the injector 35 so as to match the required pressure within a predetermined pressure range according to the gas requirement. ) Can be changed.

  In the present embodiment, as shown in FIG. 1, the injector 35 is disposed on the upstream side of the junction A <b> 1 between the hydrogen supply flow path 31 and the circulation flow path 32. Further, as shown by a broken line in FIG. 1, when a plurality of hydrogen tanks 30 are employed as the fuel supply source, the hydrogen gas supplied from each hydrogen tank 30 joins more than the part (hydrogen gas joining part A2). The injector 35 is arranged on the downstream side.

  A discharge flow path 38 is connected to the circulation flow path 32 via a gas-liquid separator 36 and an exhaust drain valve 37. The gas-liquid separator 36 collects moisture from the hydrogen off gas. The exhaust / drain valve 37 is operated according to a command from the control device 4 to discharge moisture collected by the gas-liquid separator 36 and hydrogen off-gas (fuel off-gas) containing impurities in the circulation channel 32 to the outside. (Purge). In addition, the circulation channel 32 is provided with a hydrogen pump 39 that pressurizes the hydrogen off gas in the circulation channel 32 and sends it to the hydrogen supply channel 31 side. The hydrogen off-gas discharged through the exhaust / drain valve 37 and the discharge passage 38 is diluted by the diluter 40 and merges with the oxidizing off-gas in the exhaust passage 23.

  The control device 4 detects an operation amount of an acceleration operation member (accelerator or the like) provided in the vehicle, receives control information such as an acceleration request value (for example, a required power generation amount from a load device such as the traction motor 12), Control the operation of various devices in the system. In addition to the traction motor 12, the load device is an auxiliary device (for example, a compressor 24, a hydrogen pump 39, a cooling pump motor, or the like) necessary for operating the fuel cell 10, and various types of vehicles involved in traveling of the vehicle. It is a collective term for power consumption devices including actuators used in devices (transmissions, wheel control devices, steering devices, suspension devices, etc.), occupant space air conditioners (air conditioners), lighting, audio, and the like.

  The control device 4 is configured by a computer system (not shown). Such a computer system includes a CPU, ROM, RAM, HDD, input / output interface, display, and the like, and various control operations are realized by the CPU reading and executing various control programs recorded in the ROM. It is like that.

  Specifically, the control device 4 determines the oxidizing gas and hydrogen gas required by the fuel cell 10 based on the operating state of the fuel cell 10 (current value during power generation of the fuel cell 10 detected by the current sensor 13). The amount of supply is calculated. Then, the control device 4 controls the back pressure valve 26 and the injector 35 to supply the fuel cell 10 with an oxidizing gas and hydrogen gas at a desired flow rate and pressure. At this time, the control device 4 adjusts the supply pressure of the hydrogen gas to the fuel cell 10 by changing at least one of the opening area (opening) and the opening time of the valve body of the injector 35, so that The differential pressure is always maintained below a predetermined value (hereinafter referred to as inter-electrode differential pressure control). The reason why the injector 35 is used instead of the back pressure valve 26 for the inter-electrode differential pressure control is that the injector 35 can adjust pressure with higher accuracy than the back pressure valve 26. Hereinafter, this inter-electrode differential pressure control method will be described in detail.

2. The control device 4 for controlling the differential pressure between electrodes of the fuel cell system according to the embodiment of the present invention determines whether or not the amount of change in the supply pressure of the hydrogen gas to the fuel cell 10 increases, Perform differential pressure control. This is because, particularly when the amount of change in the supply pressure of hydrogen gas is large, the inter-electrode differential pressure tends to increase.

  In the present embodiment, the control device 4 determines that the change amount of the fuel gas becomes large when the fuel cell system 1 is at the time of starting, and starts the inter-electrode differential pressure control. Hereinafter, this will be specifically described with reference to FIG.

  As shown in FIG. 2, first, the control device 4 determines whether or not the fuel cell system 1 is at start-up (start-up determination step: S1). The determination as to whether or not the system is in a starting state is made, for example, by determining the presence or absence of an operation start signal (ignition switch ON signal).

  When it is determined that the fuel cell system 1 is at the time of starting, the control device 4 acquires the supply pressure of the hydrogen gas and the oxidizing gas to the hydrogen electrode and the oxygen electrode (supply pressure acquisition step: S2). To start. Here, the supply pressure of the hydrogen gas is acquired by measuring the pressure value of the hydrogen gas at the entrance of the hydrogen electrode side by the fuel electrode side pressure sensor 43. Further, the supply pressure of the oxidizing gas is obtained by calculating the inlet pressure on the oxygen electrode side from the outlet pressure on the oxygen electrode side detected by the oxygen electrode side pressure sensor 25 and the pressure loss in the fuel cell 10.

Subsequently, the control device 4 calculates the inter-electrode differential pressure from the difference between the hydrogen gas supply pressure and the oxidizing gas supply pressure acquired in the previous step, and the inter-electrode differential pressure is equal to or higher than a predetermined pressure P _0. It is determined whether or not (differential pressure difference determination step: S3). Here, the predetermined pressure P ₀ is the maximum allowable value of the inter-electrode differential pressure, and is a specific value corresponding to the performance of the fuel cell 10.

When it is determined that the inter-electrode differential pressure is equal to or higher than the predetermined pressure P ₀ (inter-electrode differential pressure determining step: YES), the control device 4 sends an injector control command (drive signal) to the injector 35 to thereby inject the injector. 35 is controlled (injector control command process: S4). Specifically, the supply pressure of the hydrogen gas to the fuel cell 10 is reduced by changing at least one of the opening area (opening) and the opening time of the valve body of the injector 35 according to the injector control command.

When it is determined that the inter-electrode differential pressure is less than the predetermined pressure P ₀ (inter-electrode differential pressure determining step: NO) or the injector control commanding step (S4), the control device 4 determines the supply pressure of the hydrogen electrode. Is equal to or higher than the target pressure (supply pressure determination step: S5). If the pressure is equal to or higher than the target pressure, the inter-electrode differential pressure control is terminated. Return to) to continue the differential pressure control. Here, the target pressure is a pressure value of the hydrogen electrode necessary for outputting the current required for the fuel cell 10 at the time of starting the system.

  Through the above steps, the following effects are obtained. Hereinafter, it demonstrates using FIG. 3, comparing with the case where inter-electrode differential pressure control is not performed. Here, FIG. 3 is a time chart showing the time history of the hydrogen gas and oxidant gas supply pressure and the inter-electrode differential pressure in the fuel cell system at the time of starting the system, and (A) does not perform inter-electrode differential pressure control. It is a time chart of the case (comparative example), and (B) is a time chart of the case (example) when performing inter-electrode differential pressure control.

In FIG. 3A, L1 represents a time history of the hydrogen gas supply pressure, M1 represents a time history of the supply pressure of the oxidizing gas, and N1 represents a time history of the inter-electrode differential pressure. In FIG. 3B, L2 represents a time history of the hydrogen gas supply pressure, M2 represents a time history of the supply pressure of the oxidizing gas, and N2 represents a time history of the inter-electrode differential pressure. In both FIGS. 3A and 3B, P ₀ is the maximum allowable pressure difference between the electrodes, P ₂ is the target pressure of the oxidizing gas, and P ₃ is the target pressure of the hydrogen gas. Here, the difference between the target pressure (P ₃ ) of the hydrogen gas and the target pressure of the oxidizing gas (P ₂ ) is set so as not to exceed the maximum allowable value (P ₀ ) of the differential pressure between the electrodes.

(1) When no differential pressure control is performed (comparative example)
As shown in FIG. 3A, in the initial stage at the time of starting the system, the supply pressures of the hydrogen gas and the oxidizing gas increase rapidly until the respective target pressures are reached. At this time, since the pressure regulation responsiveness of the injector 35 and the back pressure valve 26 is different, the time (t ₂ ) until the supply pressure of the hydrogen gas reaches the target pressure (P ₃ ) and the supply pressure of the oxidizing gas are set to the target pressure (P ₂ ) The time to reach (t ₄ ) will be different. Therefore, even if the difference between the target pressures of hydrogen gas and oxidant gas is set so as not to exceed the maximum allowable value of the differential pressure between the electrodes, the differential pressure between the electrodes is temporarily (t ₂ to t ₃ ). , it exceeds the maximum permissible value of the inter-electrode differential pressure (P _0). On the other hand, the case where inter-electrode differential pressure control is performed is shown below.

(2) When performing differential pressure control between electrodes (Example)
Even when the inter-electrode differential pressure control is performed, as shown in FIG. 3 (B), the differential pressure between the injector 35 and the back pressure valve 26 is different at the initial stage when starting the system, so the inter-electrode differential pressure increases. (~ T ₀ ). However, when the inter-electrode differential pressure control is performed, before the inter-electrode differential pressure reaches the maximum permissible value (P ₀ ), the injector 35 is adjusted with high accuracy and promptly by a drive command from the control device 4, and the time t ₂ At ˜t ₃ , the slope of the hydrogen supply pressure increase curve L2 is adjusted to coincide with the slope of the oxygen supply pressure increase curve M2. As a result, the inter-electrode differential pressure is kept below the maximum allowable value (P ₀ ) also during the times t _{2 to} t ₃ .

  As described above in (1) and (2), when the hydrogen supply pressure suddenly increases as in the system startup, the difference in pressure regulation response between the injector 35 and the back pressure valve 26 is Although it tends to appear in the form of a temporary increase in the differential pressure (comparative example), in this embodiment, after detecting the supply pressure of the hydrogen gas and the supply pressure of the oxidizing gas, the high pressure regulation response of the injector Thus, the pressure difference between the electrodes can be kept at a value equal to or less than the maximum allowable value by quickly changing the supply pressure of the hydrogen gas with high accuracy (Example).

  In the above fuel cell system, if it is not determined that the amount of change in the supply pressure of the hydrogen gas becomes large, the difference between the target pressures of the hydrogen gas and the oxidizing gas does not exceed the maximum allowable value of the inter-electrode differential pressure. By doing so, the inter-electrode differential pressure control may be performed. At this time, since it is determined that the amount of change in the supply pressure of the fuel gas does not increase, a rapid increase in the inter-electrode differential pressure is not observed, and also due to the difference in pressure regulation response between the injector 35 and the back pressure valve 26. Since the influence does not become obvious, the pressure difference between the electrodes can be suitably maintained within a predetermined range. Thereby, the whole system can be simplified.

3. Modification of Fuel Cell System According to Embodiment of Present Invention Although the embodiment of the present invention has been described above, the present invention is not limited to this embodiment, and various modifications can be made without departing from the scope of the present invention. Implementation in an embodiment is possible. For example, the following modifications are possible.

  In the fuel cell system 1, it is determined that the amount of change in the supply pressure of the fuel gas increases when the system is started. For example, the injector upstream pressure sensor 41 and the hydrogen electrode side pressure sensor 43 Thus, the pressure of the hydrogen gas upstream and downstream of the injector 35 may be measured, and if the pressure difference is greater than a predetermined value, it may be determined that the amount of change in the fuel gas supply pressure increases. Also, combining the above two, it is determined that the amount of change in the fuel gas supply pressure increases when the system is started and the pressure difference between the upstream and downstream of the injector is greater than a predetermined value. Also good.

  In the fuel cell system 1, the supply pressure of the oxidizing gas is obtained from the measured value of the oxygen electrode side pressure sensor 25 disposed in the oxidizing gas discharge flow path 22 and the pressure loss in the fuel cell 10. However, a pressure sensor may be provided in the oxidizing gas supply path 21 to directly measure the inlet pressure of the oxidizing gas to the fuel cell.

  Moreover, in the above embodiment, although the example which provided the circulation flow path 32 in the hydrogen gas piping system 3 of the fuel cell system 1 was shown, for example, as shown in FIG. Can be directly connected to eliminate the circulation flow path 32. Even when such a configuration (dead end method) is adopted, the control device 4 sends a control signal to the injector 35 to control the opening and closing of the injector 35 in the same manner as in the above-described embodiment, thereby obtaining the same operational effects. Can do.

  Further, in each of the above embodiments, an example in which the fuel cell system according to the present invention is mounted on a fuel cell vehicle has been shown. Such a fuel cell system can also be mounted. Further, the fuel cell system according to the present invention may be applied to a stationary power generation system used as a power generation facility for a building (house, building, etc.).

1 is a configuration diagram of a fuel cell system according to an embodiment of the present invention. The flowchart for demonstrating the inter-electrode differential pressure control method of the fuel cell system which concerns on the form of this invention. The time chart which shows the time history of the supply pressure of hydrogen gas at the time of starting of a fuel cell system, and oxidizing gas, and the pressure difference between electrodes. The principal part block diagram which shows the modification of the fuel cell system which concerns on embodiment of this invention.

Explanation of symbols

1 …… Fuel cell system 10 …… Fuel cell 11 …… PCU
12 ... Traction motor 13 ... Current sensor 2 ... Oxidizing gas piping system 20 ... Humidifier 21 ... Oxidizing gas supply path 22 ... Oxidizing gas discharge path 23 ... Exhaust flow path 24 ... Compressor 25 ... Oxygen electrode side pressure sensor 26 ...... Back pressure valve (pressure regulating valve)
3... Hydrogen gas piping system 30... Hydrogen tank 31... Hydrogen supply passage 32 .. Circulation passage 33 .. Shut-off valve 34 .. Regulator 35. Injector 36 .... Gas-liquid separator 37. Valve 38 ... Discharge flow path 39 ... Hydrogen pump 4 ... Control device 40 ... Diluter 41 ... Injector upstream pressure sensor 42 ... Temperature sensor 43 ... Hydrogen electrode side pressure sensor

Claims (5)

A fuel cell having a fuel electrode and an oxidation electrode;
An injector for adjusting a supply pressure of fuel gas supplied to the fuel electrode;
A pressure regulating valve for adjusting a supply pressure of an oxidizing gas supplied to the oxidation electrode, and a fuel cell system comprising:
When it is determined that the amount of change in the supply pressure of the fuel gas becomes large, an electrode differential pressure between the fuel electrode and the oxidation electrode is within a predetermined range based on the supply pressure of the fuel gas and the supply pressure of the oxidation gas. A fuel cell system in which a supply pressure of the fuel gas is adjusted by the injector so as to be maintained inside.   The fuel cell system according to claim 1, wherein when the system is started, it is determined that the amount of change in the supply pressure of the fuel gas increases.   3. The fuel cell system according to claim 1, wherein when the difference in gas pressure between the upstream side and the downstream side of the injector is greater than a predetermined value, it is determined that the amount of change in the supply pressure of the fuel gas increases.   The injector adjusts the supply pressure of the fuel gas by controlling the operation of the valve body by an electromagnetic driving force, and the pressure regulating valve responds to at least one variation of the primary pressure, the secondary pressure, and the external pressure. The fuel cell system according to any one of claims 1 to 3, wherein a supply pressure of the oxidizing gas is adjusted by operating a valve body.   A moving body comprising the fuel cell system according to claim 1.

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