JP3923627B2 - Solid polymer electrolyte fuel cell system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a solid polymer electrolyte fuel cell system using a solid polymer membrane as an electrolyte, and relates to a solid polymer electrolyte fuel cell having an improved function of maintaining a humid state of a solid polymer membrane and space efficiency. About the system.
[0002]
[Prior art]
  A fuel cell is a device that directly converts chemical energy of a fuel into electrical energy by electrochemically reacting a fuel such as hydrogen with an oxidant such as air. Among them, solid polymer electrolyte fuel cells using a polymer ion exchange membrane as an electrolyte have features such as high output density, simple structure, and relatively low operating temperature. There are growing expectations for technological development.
[0003]
  The basic configuration of the unit cell in such a solid polymer electrolyte fuel cell will be described below with reference to FIG. In other words, the anode electrode 103 and the cathode electrode 104 are arranged with the solid polymer film 102 having ion conductivity interposed therebetween, and the unit cell 101 is configured. The anode electrode 103 is formed by an anode catalyst layer 103a and an anode porous carbon flat plate 103b. The cathode electrode 104 is formed by a cathode catalyst layer 104a and a cathode porous carbon flat plate 104b.
[0004]
  A gas-impermeable separator 105 having conductivity is disposed above and below the unit cell 101. The separator 105 is provided with grooves 103 c and 104 c for supplying reaction gas to the anode electrode 103 and the cathode electrode 104.
[0005]
  In the solid polymer electrolyte fuel cell as described above, when a fuel gas is supplied to the anode electrode 103 and an oxidant gas is supplied to the cathode electrode 104, an electrochemical reaction between the pair of electrodes of the unit cell 101 causes the following. Thus, an electromotive force is generated. That is, normally, hydrogen is used as the fuel gas and air is used as the oxidant gas. First, when hydrogen is supplied to the anode electrode 103 and air is supplied to the cathode electrode 104, the anode gas 103 is supplied. Hydrogen dissociates into hydrogen ions and electrons in the anode catalyst layer 103a. Then, hydrogen ions pass through the solid polymer film 102, and electrons move to the cathode electrode 104 through the external circuit.
[0006]
  On the other hand, in the cathode electrode 104, oxygen in the supplied air, the hydrogen ions, and electrons react in the cathode catalyst layer 104a to generate water. At this time, electrons passing through the external circuit become current and can supply power. That is, in the anode electrode 103 and the cathode electrode 104, reactions shown in the following formulas 1 and 2 proceed, respectively. The produced water is discharged out of the battery together with the unreacted gas.
[0007]
[Chemical 1]
Anode reaction: H₂→ 2H⁺+ 2e^-... Formula 1
[Chemical 2]
Cathode reaction: 2H⁺+ 1 / 2O₂+ 2e^-→ H₂O ... Formula 2
  By the way, since the electromotive force of the unit cell 101 is as low as 1 V or less, an ordinary practical fuel cell system has a battery stack in which several tens to several hundreds of unit cells 101 are stacked via the separator 105. This battery stack generates electricity. Such a battery stack rises in temperature with power generation, and a cooling plate is inserted for each of several batteries to control the temperature rise.
[0008]
  Examples of the solid polymer membrane 102 having ionic conductivity used in the solid polymer electrolyte fuel cell as described above include, for example, perfluorolocarbon sulfonic acid (Nafion) which is a proton exchange membrane.^R: DuPont, USA). This membrane has a hydrogen ion exchange group in the molecule, and functions as an ion conductive electrolyte by saturated water content, and also has a function of separating fuel and oxidant. Conversely, when the water content of the membrane decreases, the ionic resistance increases and a crossover in which the fuel and the oxidant are mixed occurs, making it impossible to generate power in the battery. For this reason, it is desirable that the solid polymer film be saturated with water.
[0009]
  On the other hand, when hydrogen ions separated at the anode electrode by power generation move to the cathode electrode through the solid polymer membrane, water also moves together. Therefore, the solid polymer membrane tends to dry on the anode electrode side. Further, when the supplied fuel or air contains less water vapor, the solid polymer membrane tends to dry near the respective reaction gas inlets. For the above reasons, it is common practice to supply a pre-humidified fuel and oxidant to the solid polymer electrolyte fuel cell.
[0010]
  Various attempts have been made as a humidifying method. The most commonly known is the fuel cell shown in US Pat. No. 5,284,718. As shown in FIG. 15, a humidified area is provided inside the battery stack. That is, the fuel gas and the oxidant gas are humidified in the humidification region by the humidifier before entering the reaction region which is the battery unit. In this humidification method, water and reaction gas are placed adjacent to each other through a semipermeable membrane, and water molecules are humidified by passing through the semipermeable membrane. The amount of humidification depends on the pressure difference between water and the reaction gas, temperature, physical property values specific to the semipermeable membrane, area, thickness, and number of sheets.
[0011]
  As another conventional technique, a humidification method proposed in JP-A-7-29591 is known. This is generally called a bubbler system. As shown in FIG. 16, a water tank T equipped with a heater is installed in the fuel line, and the fuel gas is passed through the water to humidify it. Is what you do. The amount of humidification depends on the amount of fuel gas, the temperature of the water in the tank, and the geometry of the tank.
[0012]
  Further, as another conventional technique, one using an ultrasonic transducer proposed in Japanese Patent Laid-Open No. 6-231788 is known. In this method, as shown in FIG. 17, an ultrasonic transducer S connected to a power unit P is installed inside a water tank T, and atomization of water by ultrasonic waves is performed. The reaction gas entered from is humidified and discharged from the reaction gas outlet O. The humidification amount depends on the output of the ultrasonic transducer S.
[0013]
[Problems to be solved by the invention]
  However, the conventional solid polymer electrolyte fuel cell system as described above has the following problems.
[0014]
(1) Problems with the humidifier system using a semipermeable membrane
  In the method using a humidifier using a semipermeable membrane, since it is necessary to incorporate a humidifier inside the battery stack, the entire battery stack becomes larger and heavier.
[0015]
  In addition, in order to optimize the humidified state, it is necessary to control the humidification amount according to the operating conditions. However, in the method in which the fuel gas and the oxidant gas are humidified in the humidification region before entering the reaction region, it becomes very difficult to control the humidification amount. This is because, when a certain load condition is set, the temperature and the reaction gas pressure cannot be changed greatly, and it is practically impossible to change the area and number of reaction films.
[0016]
  Therefore, in this method, the humidification amount is designed with a margin so that the relative humidity is always 100%, and it becomes impossible to flow a gas with a relatively low relative humidity in accordance with the operating conditions. . Further, in such a system, the amount of humidification is excessive, and battery performance is likely to be deteriorated due to flooding of the battery contact layer.
[0017]
(2) Problems with the bubbler system
  In the humidification method using a bubbler, the battery stack has no humidification part, so there is no problem of increasing the size and weight of the battery stack. However, since the humidifier requires a larger water tank T, the entire system becomes larger and heavier. In addition, when the electric heater H is used as a heat source, electricity generated by the battery is used, which causes a problem of reducing the efficiency of the system. Also, a large heat exchanger is required to use the heat generated during the reaction in the battery as a heat source.
[0018]
  Furthermore, the control of the humidification amount must be dealt with by changing the temperature of the water in the water tank T under a certain load condition, but the amount of water in the water tank T is large and the water tank T Since its own heat capacity is large, it is difficult to expect good responsiveness. In this system, the temperature of the reaction gas is determined by the bubbler temperature and cannot be freely controlled.
[0019]
(3) Problems with the ultrasonic method
  The humidification method using ultrasonic waves has a relatively large degree of freedom compared to the bubbler method, and the humidification amount can be controlled by the output of the ultrasonic vibrator, so that the temperature of the reaction gas can be changed independently. However, the necessity of the water tank T remains unchanged, and there is a problem in terms of increasing the size and weight of the entire system. In addition, in order to carry water atomized by ultrasonic waves, the reaction gas is purposely introduced into the water tank T and mixed with water droplets before being supplied to the battery. Becomes slower.
[0020]
(4) Common problems
  The above three conventional examples are representative, but the common basic concept of these systems is to introduce a reaction gas into a humidifier, mix it, and then supply it to the battery. . However, with this method, there is almost no flow on the water vapor side, so the mixing speed is slow. Therefore, a large space is required to obtain a sufficient mixed state.
[0021]
  The present invention has been proposed in order to solve the above-described problems of the prior art, and its purpose is to give an appropriate amount of moisture to the solid polymer electrolyte membrane and to change the operating conditions such as load conditions. Another object of the present invention is to provide a solid polymer electrolyte fuel cell system capable of controlling the humidification amount of the reaction gas so that the fuel cell can operate in an optimum state.
[0022]
  Another object of the present invention is to provide a solid polymer electrolyte fuel cell system that can be reduced in size, weight, and cost.
[0023]
[Means for Solving the Problems]
  In order to achieve the above object, the present invention provides a battery stack having at least one unit cell in which an electrolyte membrane made of a solid polymer is disposed between a fuel electrode and an oxidant electrode, and a fuel in the fuel electrode. A solid polymer electrolyte fuel cell system including a fuel supply pipe for supplying gas and an oxidant supply pipe for supplying an oxidant gas to the oxidant electrode has the following technical features.
[0024]
  That is, according to the first aspect of the present invention, humidification means for supplying water vapor or atomized water is provided in at least one of the fuel supply pipe and the oxidant supply pipe, and the humidification means is provided in the fuel supply pipe. And a rotating disk provided in at least one of the oxidant supply pipes, a nozzle for supplying water toward the rotating disk, and a pump for supplying water to the upstream side of the nozzle. And
[0025]
  In the invention according to claim 1 as described above, since the humidification amount can be arbitrarily controlled by the humidifying means, by humidifying the reaction gas by a necessary amount when necessary, responsiveness and reliable humidification can be achieved. The battery stack can always be maintained in an optimal operating state. Furthermore, the fuel gas in the fuel supply pipe, the oxidant gas in the oxidant supply pipe and the water vapor have a sufficiently high flow rate, and the mixing speed increases, so a large humidifier or a large bubbler is not required, A compact and lightweight system configuration is possible. Further, by rotating the rotating disk at high speed and supplying water to the disk, water is atomized by utilizing the phenomenon of water separation from the disk due to centrifugal force. The atomized water immediately evaporates in the surrounding reaction gas, humidifying the reaction gas. Since the mixing and humidification is forcibly performed at a high flow rate inside the reaction gas, the humidifying means can be made much more compact than the humidification mainly involving diffusion.
[0030]
DETAILED DESCRIPTION OF THE INVENTION
  Embodiments of the present invention will be described below with reference to the drawings.
[0054]
(1) Embodiment of the present invention
(Constitution)
  An embodiment of the present invention will be described with reference to FIG. This embodiment isFourth reference example belowThe configuration is substantially the same as that, except that a rotary atomization method is employed. That is, an atomization chamber 29 is provided in a part of the fuel supply pipe 2, and a rotating disk 27 connected to the motor 28 is disposed therein. The rotating disk 27 is provided with a tapered portion, and the tip of the water supply pipe 22 is disposed at a position close to the tapered portion.
[0055]
(Function)
  In the present embodiment as described above, the rotating disk 27 is rotated at a high speed by the motor 28. Then, the water supplied from the water supply pipe 22 is moved to the end of the rotary disk 27 by the centrifugal force effect by the taper portion of the rotary disk 27, and becomes a droplet from the end to form a part of the fuel supply pipe 2. It is sprayed to the atomization chamber 29 which is a part. The sprayed water evaporates as it goes downstream, humidifying the fuel gas. The amount of humidification at this time isFourth reference example belowIt is controlled by the same control.
[0056]
(effect)
  According to this embodiment as described above,First reference example belowIn addition, the droplets having a constant particle diameter can be always supplied according to a wide range of water flow rates, so that extremely stable humidification can be realized.
[0031]
(2)First reference example
(Constitution)
  First reference exampleWill be described below with reference to FIGS. That is, as shown in FIG. 1, a fuel supply pipe 2 that supplies hydrogen as a fuel gas and an air supply pipe 3 that supplies air as an oxidant gas to a battery stack 1 of a solid polymer electrolyte fuel cell. Is connected. A cooling water supply pipe 4 is connected to the battery stack 1.
[0032]
  A steam generator 5 for supplying steam is connected to the fuel supply pipe 2 and the air supply pipe 3. Here, 6 and 7 in the figure indicate entrances through which water vapor is ejected to the fuel supply pipe 2 and the air supply pipe 3, respectively. Flow control valves 16 and 17 are provided in the flow path from the water vapor generating device 5 to the fuel supply pipe 2 and the air supply pipe 3, and the humidification amount to the fuel supply pipe 2 and the air supply pipe 3 can be controlled, respectively. It has a configuration.
[0033]
  A water supply pipe 8 for supplying water is connected to the steam generator 5. The water supply pipe 8 may be provided with a pump depending on the pressure condition of the reaction gas on the downstream side, and as a pressurizing means, there is a method of pressurizing water using the pressure on the upstream side of the reaction gas.
[0034]
  Also connected to the battery stack 1 are a fuel gas discharge pipe 10 and an air discharge pipe 9 for discharging fuel gas and air that could not react in the battery stack 1, and a cooling water discharge pipe 11 for discharging cooling water. ing.
[0035]
  Further, the battery stack 1 includes a resistance value sensor 18 for detecting the electric resistance value of the solid polymer electrolyte membrane and a voltage sensor 19 for detecting the output voltage of the fuel cell as sensors for monitoring the operating state of the fuel cell. It has been incorporated. The resistance value sensor 18 and the voltage sensor 19 are connected to the control device 12. The control device 12 is connected to the water vapor generation device 5 so as to determine the operating state of the battery and to indicate the amount of water vapor generation.
[0036]
(Function)
  Like the aboveReference exampleThe operation of is as follows. That is, the battery stack 1 is supplied with hydrogen as a fuel gas from the fuel supply pipe 2 and supplied with air as an oxidant gas from the air supply pipe 3 to generate power. The heat generated inside the battery is absorbed by the cooling water supplied from the cooling water supply pipe 4 in the form of sensible heat of water, and the battery is maintained at an appropriate temperature. Further, the fuel gas and air that could not react in the battery stack 1 are discharged through the fuel gas discharge pipe 10 and the air discharge pipe 9, respectively. Further, the cooling water is discharged through the cooling water discharge pipe 11.
[0037]
  In such a power generation process, water vapor from the water vapor generating device 5 is ejected from the inlets 6 and 7 to the fuel supply pipe 2 and the air supply pipe 3, and the fuel gas and air are humidified. The controller 12 determines the operating state of the battery and controls the amount of water vapor supplied from the water vapor generator 5.
[0038]
  More specifically, when the electric resistance value is high, the solid polymer electrolyte membrane is in a dry state, but when the electric resistance value is low and the output voltage is low, the solid polymer electrolyte membrane is flooded and too wet. This means that the wet state of the film can be known from the electric resistance value and the output voltage value. Therefore, based on the electrical resistance value detected by the resistance value sensor 18 and the output voltage value detected by the voltage sensor 19, the control device 12 instructs the water vapor generation device 5 on the generation amount, so that an appropriate wet state is obtained. Is maintained.
[0039]
  An example of a control sequence by such a control device 12 is shown in FIG. The film resistance value is R, the voltage value is V, and the threshold values are Rs and Vs. That is, when the membrane resistance value R from the resistance value sensor 18 and the voltage value V from the voltage sensor 19 are input to the control device 12 (step 201). When R is larger than the threshold value Rs (step 202), a humidification amount increase command is issued to the steam generator 5 (step 203).
[0040]
  When R is smaller than the threshold value Rs and the voltage value V is smaller than the threshold value Vs (step 204), a humidification amount reduction command is issued to the steam generator 5. When R is smaller than the threshold value Rs and the voltage value V is larger than the threshold value Vs, the humidification amount of the water vapor generator is maintained, and input of the membrane resistance value R and the voltage value V is waited (step). 206).
[0041]
(effect)
  Like the aboveReference exampleAccording to the above, since the humidification amount of the fuel gas and the air is controlled while continuously monitoring the operation state of the battery stack 1, even if the operation condition changes, the solid polymer electrolyte membrane has a good wet state in accordance with the change. Therefore, it is possible to always maintain the optimum operating state.
[0042]
  In addition, since it is not necessary to provide a humidified portion in the battery stack 1 as in the above prior art, the battery stack 1 can be reduced in size and weight. Furthermore, the fuel gas in the fuel supply pipe 2 and the oxidant gas in the air supply pipe 3 have a sufficiently high flow rate, and the mixing speed with the supplied water vapor increases, so that a large humidifier, a large bubbler, etc. Therefore, it is possible to reduce the size and weight of the entire system.
[0043]
(3)Second reference example
(Constitution)
  Second reference exampleIs described below with reference to FIG. That is,Reference exampleAre provided with humidity sensors 13 and 14 on the downstream side of the water vapor inlets 6 and 7 provided in the fuel supply pipe 2 and the air supply pipe 3, respectively. The humidity sensors 13 and 14 are connected to the control device 12. In this way, the configuration other than the provision of the humidity sensors 13 and 14 in place of the resistance value sensor 18 and the voltage sensor 19 is as described above.First reference exampleIt is the same.
[0044]
(Function and effect)
  Like the aboveReference exampleThen, while the battery stack 1 is in operation, the controller 12 controls the water vapor generator 5 and the flow rate while monitoring the humidity measured by the humidity sensors 13 and 14 so that the fuel gas and air can be maintained at a preset humidity. Valves 16 and 17 are controlled. Therefore,First reference exampleAs well as obtaining the same operational effects, the humidity of the fuel gas and the air are directly measured, so that the required humidification amount can be controlled more accurately.
[0045]
(4)Third reference example
(Constitution)
  Third reference exampleWill be described with reference to FIGS. That is,Reference example, A spray nozzle 21 is installed inside the fuel supply pipe 2. The spray nozzle 21 is connected to a high-pressure pump 20 via a water supply pipe 22, and the high-pressure pump 20 is connected to a water supply pipe 8 for supplying water from the outside. The high-pressure pump 20 is provided such that its rotation speed can be controlled by the control device 12. As described above, the configuration other than the provision of the spray nozzle 21 and the high-pressure pump 20 in place of the water vapor generating device 5 and the flow rate control valves 16 and 17 is as described above.First reference exampleIt is the same.
[0046]
(Function)
  Like the aboveReference exampleThen, the water supplied from the water supply pipe 8 becomes high pressure by the high-pressure pump 20 and is supplied to the spray nozzle 21 via the water supply pipe 22. Then, as shown in FIG. 5, when the high-pressure water passes through the spray nozzle 21 having fine holes, it is atomized into small droplets having a diameter of about several tens of microns and dispersed into the fuel supply pipe 2. The atomized droplets are previously evaporated in the fuel gas and humidify the fuel gas. The amount of humidification at this time isFirst reference exampleSimilarly, the control device 12 determines the required humidification amount from the operating state of the fuel cell, feeds it back to the rotational speed of the high-pressure pump 20, and increases the rotational speed to reduce the humidification amount. When controlling by lowering the rotation speed.
[0047]
(effect)
  Like the aboveReference exampleAccording toFirst reference exampleIn addition, the humidifying means can be configured with a very simple structure and small members, so that it becomes even more compact and lightweight.
[0048]
(5)Fourth reference example
(Constitution)
  Fourth reference exampleWill be described with reference to FIGS. That is,Reference exampleIn FIG. 2, an ultrasonic nozzle 24 is provided in the fuel supply pipe 2. A water supply pipe 22 provided with a flow rate control valve 23 is connected to the ultrasonic nozzle 24. The water supply pipe 22 is connected to the water supply pipe 8 for supplying water from the outside. The ultrasonic nozzle 24 and the flow rate control valve 23 are connected to the control device 12. As described above, the configuration other than the provision of the ultrasonic nozzle 24 and the flow rate control valve 23 in place of the water vapor generation device 5 and the flow rate control valves 16 and 17 is as described above.First reference exampleIt is the same.
[0049]
(Function)
  Like the aboveReference exampleThen, the water supplied from the water supply pipe 8 is supplied to the ultrasonic nozzle 24 through the water supply pipe 22. In the ultrasonic nozzle 24, the supply water is atomized to a diameter of several tens of microns by the atomization action by ultrasonic waves, and is sprayed into the fuel supply pipe 2 to humidify the fuel gas. The amount of humidification at this time isFirst reference exampleIn the same manner as described above, the required humidification amount is determined from the operating state of the battery stack 1 and is controlled by feeding it back to the flow control valve 23. That is, when the humidification amount is increased, the valve opening is increased, and when it is desired to be decreased, the valve opening is decreased to control the humidification amount.
[0050]
(effect)
  Like the aboveReference exampleAccording toFirst reference exampleThe same effect as is obtained,Third reference exampleCompared with the high-pressure spray system shown in FIG. 1, the high-pressure pump 20 is not required, so that a simpler configuration can be achieved and further compactness can be realized.
[0051]
(6)Fifth reference example
(Constitution)
  Fifth reference exampleWill be described with reference to FIG.Reference exampleThe aboveFourth reference exampleThe throttle part 26 is provided in the fuel supply pipe 2 except that the water spray hole 25 is provided in the throttle part 26 instead of the ultrasonic nozzle 24. A water supply pipe 22 is connected to the water spray hole 25.
[0052]
(Function)
  Like the aboveReference exampleThen, the fuel gas is humidified by the water suction effect by the high-speed jet, that is, the spray effect. That is, the fuel that has passed through the fuel supply pipe 2 gradually increases in flow velocity as it approaches the throttle portion 26, but on the contrary, the pressure gradually decreases and becomes the lowest pressure in the throttle portion 26. Then, the water supplied from the water supply pipe 22 is sucked through the water spray holes 25, atomized by high-speed fuel gas, and humidified. The amount of humidification at this time is controlled by the same control as in the fourth embodiment.
[0053]
(effect)
  Like the aboveReference exampleAccording toFirst reference exampleThe same effect as is obtained,Fourth reference exampleCompared to the above, since the ultrasonic nozzle 24 is not required, the structure can be further simplified. Moreover, since the electric power for atomizing water is not required other than control of the flow control valve 23, higher power generation efficiency can be obtained.
[0057]
(7)Sixth reference example
(Constitution)
  Sixth reference exampleWill be described with reference to FIG.Reference exampleIsFirst reference exampleHowever, it is different in that the cooling water of the battery is used as the humidifying water. That is, the cooling water discharge pipe 11 of the battery stack 1 is connected to the radiator 31 via the pump 30. The radiator 31 is connected to the cooling water supply pipe 4 through a return pipe 33. The cooling water supply pipe 4 is provided with a supply valve 32. The cooling water discharge pipe 11 is also connected to the water vapor generator 5 via the pump 30.
[0058]
(Function)
  Like the aboveReference exampleThen, the cooling water discharged from the battery stack 1 is sent by the pump 30 and enters the radiator 31, cooled to the set temperature, and then supplied to the battery stack 1 again through the return pipe 33 and circulates. And a part of circulating water is guide | induced to the water vapor generator 5, and is used for humidification of a reaction gas. The humidification amount at this time is controlled by the same control as that in the first embodiment. Since the amount of cooling water gradually decreases when it is used for humidification, the replenishment valve 32 is opened to supply the missing amount.
[0059]
(effect)
  Like the aboveReference exampleAccording toFirst reference exampleThe humidifying water is heated by the waste heat of the battery in advance, so that the energy required for the heater in the steam generator 5 can be saved. Therefore, the power generation efficiency of the system is further improved.
[0060]
(8)Seventh reference example
(Constitution)
  Of the present inventionSeventh reference exampleWill be described with reference to FIG.Reference exampleThe aboveSixth reference exampleHowever, it is different in that the generated water generated during the reaction inside the fuel cell is used as humidified water. That is, a gas-liquid separator 34 is provided in the air discharge pipe 9 of the battery stack 1. The gas-liquid separator 34 is connected to the water vapor generator 5 via the pump 30.
[0061]
(Function)
  Like the aboveReference exampleThen, the exhaust air from the battery stack 1 passes through the gas-liquid separator 34, and the air and excess water are exhausted to the outside through the exhaust pipe 9. The liquid, that is, water separated in the gas-liquid separator 34 is guided to the water vapor generator 5 by the pump 30 and used as the water vapor to humidify the reaction gas. The amount of humidification at this time is controlled by the same control as in the fourth embodiment.
[0062]
(effect)
  Like the aboveReference exampleAccording toFirst reference exampleThe humidifying water is heated by the waste heat of the battery in advance, so that the energy required for the heater in the steam generator 5 can be saved. Therefore, the power generation efficiency of the system can be further improved.
[0063]
  Further, since the amount of water generated by the fuel cell is sufficient for the humidified water, it is not necessary to replenish water from the outside, and a simpler system configuration can be realized, and a reduction in size and weight can be realized.
[0064]
(9)Eighth reference example
(Constitution)
  Of the present inventionEighth reference exampleWill be described with reference to FIG.Reference exampleThe basic configuration ofFirst reference exampleThe difference is that the system is composed of a plurality of battery stacks. That is, branch portions 37, 38, 39 from the fuel supply pipe 2, the air supply pipe 3, and the cooling water supply pipe 4 are connected to the added battery stack 35. The steam inlets 6 and 7 are provided on the upstream side of the branch portions 37 and 38. The air discharge pipe 300, the fuel gas discharge pipe 301, and the cooling water discharge pipe 302 from the battery stack 35 are connected to the fuel gas discharge pipe 9, the air discharge pipe 10, and the cooling water discharge pipe 11 from the battery stack 35. Yes.
[0065]
(Function)
  Like the aboveReference exampleThen, since the steam inlets 6 and 7 are provided on the upstream side of the branch portions 37 and 38, the humidification of the plurality of battery stacks 1 and 35 can be performed with one humidifier. Then, the control device 12First reference exampleIn the same manner as described above, the electric resistance value of the solid polymer electrolyte membrane detected by the resistance value sensor 18 of the battery stack 1 and the output voltage of the battery stack 1 detected by the voltage sensor 19 are monitored to determine the operating state of the battery. To determine the amount of humidification. The control device 12 instructs the water vapor generator 5 on the necessary humidification amount, and the reaction gas is humidified accordingly.
[0066]
(effect)
  Like the aboveReference exampleAccordingly, even a fuel cell having a plurality of battery stacks 1 and 35 need not be provided with a humidifying means for each battery stack, and thus can be greatly reduced in size. In addition, the number of parts is greatly reduced, and the manufacturing cost can be greatly reduced.
[0067]
(10)Ninth reference example
(Constitution)
  Of the present inventionNinth reference exampleIs described below with reference to FIG.Reference exampleThe basic configuration ofFirst reference exampleHowever, the reaction gas is preheated through the battery stack 1 and then humidified. That is, the fuel gas supply pipe 2 and the air supply pipe 3 pass through preheating ducts 40 and 41 provided in the battery stack 1. The fuel gas supply pipe 2 and the air supply pipe 3 exiting from the preheating ducts 40 and 41 are provided with water vapor inlets 6 and 7, and further led into the battery stack 1.
[0068]
(Function)
  Like the aboveReference exampleThen, the fuel gas and air supplied from the fuel gas supply pipe 2 and the air supply pipe 3 are preheated through preheating ducts 40 and 41 provided in the battery stack 1. Then, after being humidified by the water vapor generator 5 outside the battery stack 1, it is guided into the battery stack 1 and reacts.
[0069]
(effect)
  Like the aboveReference exampleAccording to this, since the reaction gas is preheated and the water vapor is supplied in a high temperature state, the water vapor injected into the reaction gas is less likely to condense, and effective humidification is possible in a wider temperature range. Further, since the heat generated by the power generation of the battery stack 1 is used for preheating the reaction gas, it is efficient.
[0070]
(11)Other reference examples
  In the reference examples as described above, the configuration of each member can be appropriately changed as follows.For example,Second reference exampleInformation for determining the humidification amount can be obtained by using a current sensor that measures the current of the battery stack 1 instead of the humidity sensors 13 and 14 in FIG. That is, since the humidification amount is almost proportional to the load amount, if a proportional constant is set in advance, the humidification amount necessary to obtain the optimum humidity can be calculated.
[0071]
  Furthermore, since the load amount is often determined from the use side on the system, in that case, the control device 12 knows the load amount, and even if the sensor is not used, Some control is possible.
[0072]
  Further, information for determining the humidification amount can be obtained by using a fuel gas flow sensor instead of the humidity sensor. That is, since the humidification amount is substantially proportional to the fuel flow rate, if a proportional constant is set in advance, the humidification amount necessary to obtain the optimum humidity can be calculated. The same is true for the air flow rate.
[0073]
  Further, in the system, the load amount is often determined from the use side, and the load amount is also almost proportional to the reaction gas amount. In this case, the control device 12 knows the reaction gas amount. Even when the sensor is not used, a certain degree of control is possible.
[0074]
  Also, aboveThird reference exampleInstead of the pressurizing pump 20 in FIG. Also,Above 3-5 reference examplesThen, humidification on the fuel gas side is performed, but humidification on the air side can also be performed in the same manner. Also, aboveEighth reference exampleThen, although the state of the typical battery stack 1 is monitored as the operation state of the battery, an average value of the plurality of battery stacks 1 and 35 may be adopted. As a means for monitoring the humidified state,Second reference exampleA humidity sensor such as that described above may be used, or a flow rate sensor may be used. Furthermore, the humidifying means is not limited to the steam generator shown in FIG.Third to fifth reference examplesVarious humidifying means as described above can be applied.
[0076]
【The invention's effect】
  As described above, according to the present invention, the solid polymer electrolyte membrane is supplied with an appropriate amount of water, and even if the operating conditions such as the load conditions change, the reaction gas can be operated so as to operate in an optimum state as a fuel cell. It is possible to provide a solid polymer electrolyte fuel cell system capable of controlling the amount of humidification. In addition, it is possible to provide a solid polymer electrolyte fuel cell system that can be reduced in size, weight, and cost.
[Brief description of the drawings]
FIG. 1 shows a solid polymer electrolyte fuel cell system.First reference exampleFIG.
FIG. 2 of FIG.Reference exampleIt is a flowchart showing the basic sequence of the humidification control in.
[Fig. 3] Solid polymer electrolyte fuel cell systemSecond reference exampleFIG.
FIG. 4 shows a solid polymer electrolyte fuel cell system.Third reference exampleFIG.
FIG. 5 is the same as FIG.Reference exampleIt is sectional drawing which shows the fuel gas supply pipe | tube in the vicinity of the spray nozzle in.
FIG. 6 shows a solid polymer electrolyte fuel cell system.Fourth reference exampleFIG.
7 is a diagram of FIG.Reference exampleIt is sectional drawing which shows the fuel gas supply pipe | tube in the vicinity of the ultrasonic nozzle in.
FIG. 8 shows a solid polymer electrolyte fuel cell system.Fifth reference exampleIt is sectional drawing which shows the fuel gas supply pipe | tube of the throttle part vicinity in FIG.
FIG. 9 is a cross-sectional view showing a fuel gas supply pipe in the vicinity of a rotary atomizer in an embodiment of a solid polymer electrolyte fuel cell system of the present invention.
FIG. 10 shows a solid polymer electrolyte fuel cell system.Sixth reference exampleFIG.
FIG. 11 shows a solid polymer electrolyte fuel cell system.Seventh reference exampleFIG.
FIG. 12 shows a solid polymer electrolyte fuel cell system.Eighth reference exampleFIG.
FIG. 13 shows a solid polymer electrolyte fuel cell system.Ninth reference exampleFIG.
FIG. 14 is a cross-sectional view showing an example of a single cell structure of a conventional fuel cell.
FIG. 15 is a side view showing an example of a conventional fuel cell system having a humidified portion inside a battery stack.
FIG. 16 is a configuration diagram showing an example of a conventional fuel cell system provided with a bubbler as a humidifier.
FIG. 17 is a cross-sectional view showing an example of a conventional battery stack including an ultrasonic atomizer as a humidifier.
[Explanation of symbols]
1,35 ... Battery stack
2 ... Fuel supply pipe
3 ... Air supply pipe
4 ... Cooling water supply pipe
5 ... Steam generator
6, 7 ... Steam inlet
8, 22 ... Water supply pipe
9,300 ... Air exhaust pipe
10, 301 ... Fuel gas discharge pipe
11, 302 ... Cooling water discharge pipe
12 ... Control device
13, 14 ... Humidity sensor
16, 17, 23, 32 ... flow control valve
18 ... Resistance sensor
19 ... Voltage sensor
20 ... High pressure pump
21 ... Spray nozzle
24 ... Ultrasonic nozzle
25 ... Water spout
26: Aperture section
27 ... Rotary disk
28 ... Motor
29 ... Atomization room
30 ... circulation pump
31 ... Radiator
33 ... Cooling water return pipe
34 ... Gas-liquid separator
37, 38, 39 ... branching part
40, 41 ... Preheating duct
101 ... single cell
102 ... Solid polymer membrane
103 ... Anode electrode
103a ... anode catalyst layer
103b ... Anode porous carbon flat plate
103c ... Fuel supply groove
104 ... Cathode electrode
104a ... Cathode catalyst layer
104b ... Cathode porous carbon flat plate
104c ... Oxidant supply groove
105 ... Separator

Claims (1)

A battery stack having at least one unit cell in which an electrolyte membrane made of a solid polymer is disposed between a fuel electrode and an oxidant electrode, a fuel supply pipe for supplying fuel gas to the fuel electrode, and the oxidant electrode A solid polymer electrolyte fuel cell system including an oxidant supply pipe for supplying an oxidant gas to
At least one of the fuel supply pipe and the oxidant supply pipe is provided with a humidifying means for supplying water vapor or atomized water,
The humidifying means includes a rotary disk provided in at least one of the fuel supply pipe and the oxidant supply pipe, a nozzle that supplies water toward the rotary disk, and a pump that supplies water upstream of the nozzle. And a solid polymer electrolyte fuel cell system.

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