JP2006004819A - Fuel cell system and fuel cell vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable to retain a degree of wetness of a solid polyelectrolyte membrane at the optimum without restricting power generation amount of a fuel cell. <P>SOLUTION: A controller 61 to control a fuel cell system 1 is provided with a fuel cell wet state estimating means 63, an oxidation gas supply pressure control means 65, and an oxidation gas supply flow amount control means 67. The degree of wetness H of the solid polyelectrolyte membrane of a fuel cell stack 3 is estimated by the fuel cell wet state estimating means 63. When the degree of wetness H has a prescribed value or less, pressure of the oxidation gas supplied from an oxidation gas supply device 7 is increased and controlled by the oxidation gas supply pressure control means 65. When the degree of wetness H has the prescribed value or more, the oxidation gas supply amount control means 67 increases and controls the flow rate of the oxidation gas supplied from the oxidation gas supply device 7. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a fuel cell system and a fuel cell vehicle.

  In a fuel cell, a fuel gas such as hydrogen gas and an oxidizing gas containing oxygen are electrochemically reacted through an electrolyte, and electric energy is directly taken out between electrodes provided on both surfaces of the electrolyte. In particular, a polymer electrolyte fuel cell using a polymer electrolyte has attracted attention as a power source for electric vehicles because of its low operating temperature and easy handling. That is, a fuel cell vehicle is equipped with a hydrogen storage device such as a high-pressure hydrogen tank, a liquid hydrogen tank, or a hydrogen storage alloy tank in the vehicle, and reacts by supplying hydrogen supplied therefrom and air containing oxygen to the fuel cell. This is the ultimate clean vehicle that drives the motor connected to the drive wheels with the electric energy extracted from the fuel cell, and the only exhaust material is water.

  By the way, it is known that perfluorosulfonic acid polymers and the like that are general solid polymer electrolytes do not exhibit good hydrogen ion conductivity unless the water content is sufficient. For this reason, as a humidification method for supplying moisture to the solid polymer electrolyte, an external humidification (indirect humidification) method for humidifying the fuel gas or oxidant gas supplied to the fuel cell main body, or a cooling water circulating through the fuel cell main body is used. An internal humidification (direct humidification) method of humidifying through a material member is performed.

  Further, a technique for providing a sensor integrated with a solid polymer electrolyte membrane in order to monitor the wet state of the solid polymer electrolyte membrane of a fuel cell is known (for example, Patent Document 1).

According to this technology, parameters such as temperature, hydration state, ionic conductivity, AC impedance, resistance, capacitance, dielectric constant, complex dielectric constant and bulk dielectric constant of the fuel cell stack cell / membrane electrode assembly are monitored. Therefore, the wet state of the fuel cell stack and the power generation efficiency can be estimated.
Japanese translation of PCT publication No. 2002-536788 (page 8, FIG. 1)

  However, in the above prior art, when the wetness of the solid polymer electrolyte is decreased, when the fuel cell stack is clogged, or when the amount of pure water for humidifying the oxidizing gas supplied to the fuel cell is decreased. Accordingly, it is necessary to change the operating point of the pressure and flow rate of the oxidizing gas supplied to the fuel cell.

  For example, if the wetness of the solid polymer electrolyte membrane decreases, the power generation efficiency decreases, so the amount of heat generated by the fuel cell increases, and the wetness of the solid polymer electrolyte membrane further decreases. There was a problem of not becoming.

  Further, if power generation is continued in a state where the fuel cell stack is clogged, there is a risk that the fuel cell stack will deteriorate due to a shortage of gas supplied to the electrode catalyst. Further, when the amount of pure water for humidifying the oxidizing gas is lowered, sufficient humidification cannot be performed on the oxidizing gas, the resistance of the solid polymer electrolyte membrane is increased, and the power generation efficiency of the fuel cell is lowered.

  In order to solve the above problems, a first invention is a fuel cell system including a fuel cell main body that generates power using fuel gas and oxidizing gas, and an oxidizing gas supply device that supplies the oxidizing gas to the fuel cell main body. A fuel cell wet state estimating means for estimating the internal wetness of the fuel cell main body, and a flow rate of the oxidizing gas supplied from the oxidizing gas supply device based on the internal wetness estimated by the fuel cell wet state estimating means And an oxidizing gas supply pressure control means for controlling the pressure of the oxidizing gas supplied from the oxidizing gas supply device based on the internal wetness estimated by the fuel cell wet state estimating means. The summary is provided.

  The second invention is a fuel cell vehicle comprising the fuel cell system of the first invention and a vehicle drive motor that drives the vehicle and can convert kinetic energy into regenerative power when the vehicle decelerates. The gist is to control the oxidizing gas supply device so as to consume the regenerative electric power converted by the vehicle driving motor.

  According to the first invention, since the oxidizing gas pressure and the oxidizing gas flow rate are controlled based on the wetness of the solid polymer membrane of the fuel cell body, the wetness of the solid polymer membrane can be appropriately controlled. it can.

  According to the second aspect of the invention, the regenerative power can be consumed by the oxidizing gas supply device during regenerative braking by the vehicle drive motor, so that the internal wetness of the fuel cell main body can be maintained even when the fuel cell power generation amount is not more than a predetermined value. Can be properly controlled, and water clogging of the fuel cell stack can be prevented.

  Next, embodiments of the present invention will be described in detail with reference to the drawings. The fuel cell system described in each of the following embodiments is a fuel cell system suitable for a fuel cell vehicle.

  FIG. 1 is a system configuration diagram illustrating the configuration of a first embodiment of a fuel cell system according to the present invention. In FIG. 1, a fuel cell system 1 includes a fuel cell stack 3 that is a fuel cell body provided with a solid polymer electrolyte membrane, a humidifier 5 that humidifies oxidizing gas and hydrogen supplied to the fuel cell stack 3, and an oxidizing gas. As an oxidizing gas supply device 7 such as a compressor for supplying air, a throttle 9 for adjusting the pressure flow rate of air discharged from the fuel cell stack 3, a high-pressure hydrogen tank 11 for storing hydrogen, and a hydrogen pressure are adjusted. A variable valve 13, an ejector 15 for mixing and circulating new hydrogen supplied from the variable valve 13 and an anode off gas discharged from the anode of the fuel cell stack 3, and a purge valve 17 for discharging the anode off gas to the outside of the system And a drive unit 19 that consumes the electric power generated by the fuel cell stack 3.

  The fuel cell system 1 includes a pure water supply device 27 such as a pump that supplies pure water to the humidifier 5, a pure water radiator 23 that lowers the temperature of pure water, and a fan 25 that blows air to the pure water radiator 23, A pure water tank 29 for storing pure water and a water level sensor 31 for detecting the water level of the pure water tank 29 are provided.

  Further, since the fuel cell system 1 adjusts the temperature of the fuel cell stack 3 and supplies cooling water to a cooling water passage (not shown) formed inside the fuel cell stack 3, a cooling water supply device 37 such as a pump. A cooling water radiator 33 that discharges heat of the cooling water to the outside of the system, and a fan 35 that blows air to the cooling water radiator 33.

  In addition, the fuel cell system 1 detects the atmospheric pressure sensor 49 that detects the atmospheric pressure and the temperature and humidity that detects the temperature and humidity of the air sucked by the oxidizing gas supply device 7 in order to detect / control the operating state of the fuel cell system. Sensor 51, oxidizing gas flow sensor 41 for detecting the oxidizing gas flow rate at the inlet of the fuel cell stack 3, hydrogen flow sensor 43 for detecting the hydrogen gas flow rate, oxidizing gas pressure sensor 45 for detecting the oxidizing gas pressure, hydrogen gas A hydrogen gas pressure sensor 47 for detecting pressure, a temperature sensor 53 for detecting a coolant temperature at the outlet of the fuel cell stack, and a voltage of each cell constituting the fuel cell stack 3 or a cell group composed of a plurality of cells connected in series. A cell voltage detector 21 and a controller 61 for inputting detection signals of these sensors are provided.

  The controller 61 controls the entire fuel cell system 1, and based on the wetness estimated by the fuel cell wet state estimation unit 63 and the fuel cell wet state estimation unit 63 that estimates the internal wetness of the fuel cell stack 3. Based on the wetness estimated by the oxidizing gas supply pressure control means 65 for controlling the discharge pressure of the oxidizing gas supply apparatus 7 and the fuel cell wet state estimation means 63, the flow rate of the oxidizing gas supplied from the oxidizing gas supply apparatus 7 is controlled. And an oxidizing gas supply flow rate control means 67.

Here, the internal wetness H of the fuel cell stack 3 is the wetness of the solid polymer electrolyte membrane used in the fuel cell stack 3, for example, per unit area of the solid polymer electrolyte membrane in the operating state. The water content W [g / cm ² ] was normalized by dividing by the water content W 0 [g / cm ² ] per unit area of the solid polymer electrolyte membrane under the usage conditions recommended by the manufacturer of the solid polymer electrolyte membrane An anonymous number.

H = W / W0 (1)
The controller 61 is not particularly limited, but in this embodiment, the controller 61 is constituted by a microprocessor including a CPU, a ROM that stores a control program, control parameters, and a control table, a working RAM, and an input / output interface. . The controller 61 takes in the signal of each sensor and the output of the cell voltage detection device 21 and outputs a control signal for driving each actuator based on a built-in control program.

  Next, the operation of the fuel cell system 1 configured as described above will be described. In the oxidizing gas system, the oxidizing gas supply device 7 compresses the air as the oxidizing gas and sends it to the humidifier 5. The humidifier 5 humidifies the air with pure water supplied from the pure water supply device 27 and sends it to the fuel cell stack 3. In the hydrogen system, the variable valve 13 controls the pressure of the hydrogen supplied from the high-pressure hydrogen tank 11, and the hydrogen pressure supplied to the fuel cell stack 3 is set to a desired value. The ejector 15 merges with the anode off-gas and then is sent to the humidifier 5. The humidifier 5 humidifies hydrogen with pure water supplied by the pure water supply device 27 in the same manner as the oxidizing gas, and the humidified hydrogen. Is fed into the fuel cell stack 3.

  In the fuel cell stack 3, the supplied air and hydrogen are reacted to generate power and supply current (electric power) to the drive unit 19. The remaining air used for the reaction in the fuel cell stack 3 is subjected to pressure control by the throttle 9 and discharged outside the system. The remaining hydrogen used in the reaction is discharged from the fuel cell stack 3, but is returned to the upstream side of the humidifier 5 by the ejector 15 and reused for power generation.

  The controller 61 includes the oxidizing gas supply device 7, the flow rate value and the pressure value read from each of the flow rate sensors 41, 43 and the pressure sensors 45, 47 so as to become predetermined target values determined from the target power generation amount at that time. The throttle 9 and the variable valve 13 are controlled, and an output (current value) command is output from the fuel cell stack 3 to the drive unit 19 according to the pressure and flow rate actually realized with respect to the target values.

  The drive unit 19 includes a vehicle drive motor (not shown), drives the vehicle by supplying the power generated by the fuel cell stack 3 to the vehicle drive motor, and the vehicle drive motor is used during vehicle braking. The regenerative braking for braking the vehicle can be performed by converting the kinetic energy of the vehicle into regenerative electric power. During this regenerative braking, the controller 61 can control to increase the rotational speed of the oxidizing gas supply device 7 and increase the opening of the throttle 9 to consume excess regenerative power. Yes.

  Next, the control action of the controller 61 will be described with reference to a flowchart and a control map. The general action of the controller 61 is to estimate the internal wet state of the fuel cell stack 3 and to control the oxidizing gas supply device 7 and the throttle 9 based on this wet state to appropriately control the wet state.

  FIG. 8 is a general flowchart for explaining the entire control contents executed by the controller 61 every predetermined time (for example, every 10 [ms]) from the start of operation of the fuel cell system. First, in step (hereinafter, step is abbreviated as S) 10, the controller 61 estimates the wet state of the solid polymer membrane of the fuel cell stack 3. Next, in S12, the controller 61 controls the supply flow rate of the oxidizing gas supplied to the fuel cell stack 3 based on the estimated wet state. Next, in S14, the controller 61 performs the control based on the estimated wet state. The supply pressure of the oxidizing gas supplied to the fuel cell stack 3 is controlled.

  Next, a method for estimating the wetness of the solid polymer membrane of the fuel cell stack 3 in S10 will be described with reference to FIG. 2A is a diagram showing the relationship between the intake oxidant gas (air) temperature and the saturated water vapor partial pressure, and FIG. 2B is a diagram showing the relationship between the saturated water vapor partial pressure and the wetness of the solid polymer membrane. FIG.

For example, when the oxidizing gas supplied to the fuel cell stack 3 is humidified 100%, the temperature and humidity sensor 51 detects the intake oxidizing gas temperature of the oxidizing gas supply device 7, and this intake oxidizing gas. From the temperature T _{CMP_IN1} [degC], a saturated water vapor partial pressure f ₁ [mmHg] is calculated with reference to a control map as shown in FIG. Furthermore, the relationship between the saturated water vapor partial pressure and the solid polymer film wetness is obtained in advance by experiments or the like, and the obtained relationship is stored in the controller 61 as a control map as shown in FIG. Then, based on the intake oxidant gas temperature T _{CMP — IN1} [degC], there is a method of calculating the solid polymer film wetness H ₁ by sequentially referring to the control maps of FIGS. 2A and 2B. . In addition, there is a method for estimating the wetness of the solid polymer film from the humidity of the inhaled oxidizing gas of the oxidizing gas supply device 7 detected by the temperature / humidity sensor 51.

Next, the oxidizing gas supply flow rate control method of S12 will be described using the flowchart of FIG. First, in S16, if the wetness H ₁ of the solid polymer membrane of the fuel cell stack 3 is equal to or more than a predetermined value, and determined to be equal to or greater than the predetermined value, in S18, the fuel cell stack 3 is corrected by increasing the flow rate of the oxidizing gas supplied to 3 and the process ends. If it is determined in S16 that it is not equal to or greater than the predetermined value, the process ends without doing anything.

Here, the fuel cell supply oxidizing gas flow rate correction method of S18 will be described with reference to FIG. The relationship between the wetness of the solid polymer film and the oxidizing gas target flow rate correction coefficient is obtained in advance by experiments or the like, and the obtained relationship is stored in the controller 61 as a control map as shown in FIG. Then, based on the solid polymer film wetness H ₁ estimated in S10, the oxidizing gas flow rate correction coefficient k _H1 is calculated with reference to the map of FIG.

If the target oxidant gas flow rate before correction when the fuel cell power generation amount is G ₁ [W] is Q _Target1 [L / min], the corrected oxidant gas target flow rate Q _kH1 [L / min] is (2) can be calculated (FIG. 3B).

Q _kH1 = Q _Target1 × k _H1 [L / min] (2)
As described above, the oxidizing gas flow rate is corrected to increase.

In addition, as shown in FIG. 4, when the estimated solid polymer film wetness exceeds a predetermined value (1 or more in FIG. 4), the flow rate of the oxidizing gas supplied to the fuel cell stack 3 is predetermined. When the rate of increase is corrected with the rate of change Q _inc [L / min / sec] and the solid polymer membrane wetness falls below the predetermined value, the oxidizing gas flow rate is set at the predetermined rate of change Q _dec [L / min / sec]. There is a method of correcting the decrease.

  Next, the oxidizing gas supply pressure control method of S14 will be described using the flowchart of FIG. First, in S20, it is determined whether or not the wetness of the solid polymer membrane of the fuel cell is equal to or less than a predetermined value. If it is determined that it is equal to or less than the predetermined value, the discharge of the oxidizing gas supply device 7 is performed in S22. By correcting the pressure to increase, the oxidizing gas supply pressure is corrected to increase, and the process ends. If it is determined in S20 that the value is not less than the predetermined value, the process ends without doing anything.

Here, the correction method for increasing the oxidizing gas supply pressure in S22 will be described with reference to FIG. The relationship between the solid polymer film wetness and the oxidizing gas target pressure correction coefficient is obtained in advance by experiments or the like, and the obtained relationship is stored in the controller 61 as a control map as shown in FIG. Then, based on the solid polymer film wetness H ₂ calculated in S10, the target discharge pressure correction coefficient k _H2 is calculated with reference to the map of FIG.

If the target discharge pressure before correction when the power generation amount of the fuel cell is G ₁ [W] is P _{OUT_Target2} [kPa], the corrected target discharge pressure P _{OUT_kH2} [kPa] is calculated by the following equation (3). (FIG. 5B).

P _{OUT_kH2} = P _{OUT_Target2} × k _H2 [kPa] (3)
As described above, the oxidizing gas pressure is corrected to be increased.

In addition, as shown in FIG. 6, when the estimated solid polymer film wetness is equal to or less than a predetermined value (1 or less in the upper diagram of FIG. 6), the discharge pressure of the oxidizing gas supply device is changed by the rate of change. When the increase correction is performed with P _{OUT_inc} [kPa / sec] and the solid polymer film wetness exceeds a predetermined value, the discharge pressure is decreased and corrected with the rate of change P _{OUT_dec} [kPa / sec]. is there.

  According to the present embodiment, since the oxidizing gas pressure and the oxidizing gas flow rate are controlled based on the wetness of the fuel cell solid polymer membrane, the wetness of the solid polymer membrane can be appropriately controlled.

  Further, according to the present embodiment, when the wetness of the fuel cell solid polymer membrane is equal to or higher than a predetermined value, the amount of oxidant gas is corrected to increase, so the wetness of the solid polymer membrane is appropriately controlled, Flooding can be prevented.

  Furthermore, according to this embodiment, when the wetness of the solid polymer membrane of the fuel cell is below a predetermined value, the oxidizing gas discharge pressure is increased and corrected, so that the wetness of the solid polymer membrane is controlled appropriately. be able to.

  Next, a second embodiment of the fuel cell system according to the present invention will be described. The configuration of the fuel cell system of Example 2 is the same as that of Example 1 shown in FIG. 1, and the control of the oxidizing gas flow rate and the oxidizing gas pressure has been described with reference to FIGS. Since it is the same as that of Example 1, the overlapping description is abbreviate | omitted.

  In the fuel cell system of the second embodiment, whether or not the fuel cell stack 3 is clogged based on the cell voltage detected by the cell voltage detection device 21 in addition to the function of the fuel cell system of the first embodiment. If it is determined that water clogging has occurred, the supply flow rate of the oxidizing gas supplied from the oxidizing gas supply device 7 is increased to eliminate the water clogging.

  Next, the operation of the second embodiment will be described. First, in the flowchart of FIG. 11, the clogged state of the fuel cell stack 3 is estimated in step S24. Here, the method for estimating the clogged state of the fuel cell stack 3 in S24 will be described.

  In the present embodiment, when a cell or a cell group that is equal to or lower than a predetermined voltage value is detected from among the voltage values of the cell or cell group detected by the cell voltage detection device 21, the same cell or the same group is detected. When the state of the cell group continues below the predetermined voltage value for a predetermined time or more, it is estimated that the fuel cell stack 3 is clogged.

  In addition to this, as a method of estimating the water clogging state of the fuel cell stack 3, the average value of the voltage of the cell or cell group detected by the cell voltage detection device 21 is obtained, and the cell deviated downward from the average value by a predetermined ratio or more. Alternatively, it may be estimated that the fuel cell stack 3 is clogged when the voltage value of the cell group continues for a predetermined time or more.

  Next, the flow rate increase correction of the fuel cell supply oxidizing gas in this embodiment will be described with reference to the flowchart of FIG.

  In S26, it is determined whether or not the fuel cell stack 3 is clogged. If it is determined that the fuel cell stack 3 is clogged, the oxidation supplied from the oxidizing gas supply device 7 to the fuel cell stack 3 is determined in S28. The gas flow rate is increased and corrected.

Here, the flow rate correction method of the fuel cell supply oxidizing gas in S26 will be described with reference to FIG. As shown in FIG. 7, when it is determined that the fuel cell stack 3 is clogged, the flow rate of the oxidizing gas supplied from the oxidizing gas supply device 7 to the fuel cell stack 3 is set to a predetermined change rate Q _inc [L / When the increase is corrected at min / sec] and it is determined that no water clogging has occurred, the flow rate of the oxidizing gas supplied from the oxidizing gas supply device 7 to the fuel cell stack 3 is set to a predetermined change rate Q _dec [L / min / sec. ], Etc., there is a way to compensate for decrease.

  According to this embodiment, when the clogging of the fuel cell stack is detected, the oxidizing gas flow rate is increased and corrected, so that flooding can be prevented.

  Next, a third embodiment of the fuel cell system according to the present invention will be described. The configuration of the fuel cell system of Example 3 is the same as that of Example 1 shown in FIG. 1, and the control of the oxidizing gas flow rate and the oxidizing gas pressure has been described with reference to FIGS. Since it is the same as that of Example 1, the overlapping description is abbreviate | omitted.

  In addition to the function of the fuel cell system of the first embodiment, the fuel cell system of the third embodiment is used for humidifying the humidifier 5 that humidifies the oxidizing gas (air) and the fuel gas (hydrogen) supplied to the fuel cell stack 3. When the water level of the pure water tank 29 that supplies the pure water is detected by the water level gauge 31 and the detected pure water amount is not more than a predetermined value, the increase correction of the flow rate of the oxidizing gas supplied from the oxidizing gas supply device 7 is prohibited. It is characterized by doing.

  Next, the operation of the third embodiment will be described. First, in the flowchart of FIG. 13, in step S30, the oxidant gas supplied to the fuel cell stack 3 and the amount of pure water that can be supplied to the humidifier 5 that humidifies the fuel gas are detected by the water level gauge 31 provided in the pure water tank 29. .

  Next, the increase prohibition control of the oxidizing gas supply flow rate according to the amount of pure water that can be supplied will be described with reference to the flowchart of FIG. First, in S32 of FIG. 14, it is determined whether or not the amount of pure water that can be supplied is greater than or equal to a predetermined value based on the detection value of the water level sensor 31. When the flow rate of the oxidizing gas supplied to the fuel cell is increased and corrected, and it is determined that the flow rate is equal to or less than the predetermined value, the flow is terminated without performing the increase correction of the oxidizing gas flow rate.

  The method for correcting the increase in the fuel cell supply oxidizing gas flow rate in S34 is the same as the method described in the first embodiment, and is therefore omitted.

  The present embodiment described above is indirect humidification in which the oxidizing gas and the fuel gas supplied to the fuel cell stack 3 via the humidifier are humidified. However, a pure water passage is provided inside the fuel cell stack 3, and It is apparent that the present invention can also be applied to a fuel cell that directly humidifies a reaction gas or a solid polymer electrolyte membrane supplied from a water passage to a fuel cell via a porous member.

  According to the present embodiment, when the amount of pure water that can be supplied to the fuel cell is equal to or less than a predetermined value, the amount of pure gas supplied to the fuel cell can be prevented from being decreased because the increase in the oxidizing gas flow rate is corrected. .

  Next, Embodiment 4 which is a fuel cell vehicle provided with the fuel cell system according to the present invention will be described. The configuration of the fuel cell system of Example 4 is the same as the configuration of Example 1 shown in FIG. 1, and the control of the oxidizing gas flow rate and the oxidizing gas pressure has been described with reference to FIGS. Since it is the same as that of Example 1, the overlapping description is abbreviate | omitted.

  In addition to the functions of the fuel cell system according to the first embodiment, the fuel cell system according to the fourth embodiment includes a vehicle drive motor (not shown) provided in the drive unit 19 when regenerative braking is performed on the fuel cell vehicle. Control is performed so that the regenerative electric power generated in step 1 is consumed by the oxidizing gas supply device 7.

  When the vehicle drive motor is performing regenerative braking, the controller 61 suppresses the power generation amount of the fuel cell to a predetermined value or less or stops power generation. At this time, the oxidizing gas supply device 7 continues to supply the oxidizing gas by consuming the regenerative power generated by the vehicle driving motor.

  According to the fourth embodiment, since regenerative power is consumed by the oxidizing gas supply device during regenerative braking by the vehicle drive motor, when the vehicle drive motor generates regenerative power, that is, the amount of fuel cell power generation Even when is less than or equal to a predetermined value, the wetness of the fuel cell solid polymer membrane can be properly controlled, and water clogging of the fuel cell stack can be prevented.

1 is a system configuration diagram illustrating a configuration of a fuel cell system according to the present invention. (A) The figure explaining the relationship between suction | inhalation oxidizing gas temperature and a saturated water vapor partial pressure, (b) It is a figure explaining the relationship between a saturated water vapor partial pressure and a solid polymer film wetness. (A) The figure explaining the relationship between a solid polymer film wetness and an oxidizing gas flow rate correction coefficient, (b) The figure explaining the relationship between a fuel cell power generation amount and an oxidizing gas target flow rate. It is a figure explaining the increase correction | amendment control method of oxidizing gas supply flow rate. (A) It is a figure explaining the relationship between a solid polymer film wetness and an oxidizing gas discharge pressure correction coefficient, (b) It is a figure explaining the relationship between fuel cell electric power generation amount and oxidizing gas target discharge pressure. It is a figure explaining the increase correction | amendment control method of oxidizing gas supply pressure. It is a figure explaining the increase correction | amendment control method of the oxidizing gas supply flow rate at the time of water clogging detection of a fuel cell stack. 2 is a main flowchart of the fuel cell system according to the present invention. It is a flowchart explaining the increase correction | amendment of a fuel cell supply oxidizing gas flow rate. It is a flowchart explaining the increase correction | amendment of fuel cell supply oxidizing gas pressure. It is a flowchart explaining the water clogging state estimation of a fuel cell stack. It is a flowchart explaining the increase correction | amendment of the fuel cell supply oxidizing gas flow volume according to the water blockage state of a fuel cell stack. It is a flowchart which detects the amount of pure water which can be supplied to a fuel cell. It is a flowchart explaining the increase correction | amendment of the fuel cell supply oxidizing gas flow volume according to the amount of pure water.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Fuel cell system 3 ... Fuel cell stack 5 ... Humidifier 7 ... Oxidizing gas supply device 9 ... Throttle 11 ... High pressure hydrogen tank 13 ... Variable valve 15 ... Ejector 17 ... Purge valve 19 ... Drive unit 21 ... Cell voltage detection device 23 ... Pure water radiator 25 ... Fan 27 ... Pure water supply device 29 ... Pure water tank 31 ... Water level gauge 61 ... Controller 63 ... Fuel cell wet state estimation means 65 ... Oxidation gas supply pressure control means 67 ... Oxidation gas supply flow rate control means

Claims (6)

In a fuel cell system comprising a fuel cell main body provided with a solid polymer electrolyte and an oxidizing gas supply device for supplying an oxidizing gas to the fuel cell main body,
Fuel cell wet state estimating means for estimating the internal wetness of the fuel cell body;
An oxidizing gas supply flow rate control means for controlling the flow rate of the oxidizing gas supplied from the oxidizing gas supply device based on the internal wetness estimated by the fuel cell wet state estimating means;
An oxidizing gas supply pressure control means for controlling the pressure of the oxidizing gas supplied from the oxidizing gas supply device based on the internal wetness estimated by the fuel cell wet state estimating means;
A fuel cell system comprising:   2. The oxidant gas supply flow rate control unit corrects the oxidant gas supply flow rate to increase when the internal wetness estimated by the fuel cell wet state estimation unit is greater than or equal to a predetermined value. The fuel cell system described. Comprising water clogging detection means for detecting clogging of the fuel cell main body,
3. The fuel cell according to claim 1, wherein, when the water clogging detecting unit detects water clogging, the oxidizing gas supply flow rate control unit corrects the amount of increase in the oxidizing gas supply flow rate. system. Comprising pure water amount detecting means for detecting the amount of pure water that can be indirectly or directly supplied to the fuel cell body;
3. The increase correction of the oxidizing gas supply flow rate by the oxidizing gas supply flow rate control unit is prohibited when the pure water amount detected by the pure water amount detection unit is less than a predetermined value. 3. The fuel cell system according to 3.   2. The oxidant gas supply pressure control unit corrects the oxidant gas supply pressure to increase when the internal wetness estimated by the fuel cell wet state estimation unit is a predetermined value or less. The fuel cell system described. A fuel cell system according to any one of claims 1 to 5,
A fuel cell vehicle comprising: a vehicle driving motor capable of converting kinetic energy into regenerative power when the vehicle is decelerated while driving the vehicle;
A fuel cell vehicle, wherein the oxidizing gas supply device is controlled to consume regenerative power converted by the vehicle drive motor.

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