JP2009181806A - Fuel cell system and its operation method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a normal pressure direct water injection type fuel cell system capable of enhancing power generation performance in heavy load operation, and to provide its operation method. <P>SOLUTION: In the fuel cell system and its operation method, a request load amount to a fuel cell is obtained with a request load obtaining means, and the particle size of liquid water injected from a nozzle is varied with a particle size varying means according to the request load amount obtained like this. Since the particle size of liquid water injected from the nozzle is varied according to the request load amount, the particle size of the liquid water injected from the nozzle can be made small in the heavy load operation. As a result, blocking of an oxidant gas passage to an air electrode can be suppressed, the supply amount of oxidant gas which was apt to become insufficient by blocking of the oxidant gas passage in the heavy load operation can be made sufficient, and power generation performance in the heavy load operation can be enhanced. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a direct fountain type fuel cell system that injects liquid water in the form of a mist into an oxygen electrode of a fuel cell and an operation method thereof, and more particularly, a fuel cell system that can improve power generation performance during high load operation and the operation thereof It is about the method.

  A unit cell of a polymer electrolyte fuel cell has a structure in which a solid polymer electrolyte membrane is sandwiched between a fuel electrode (hydrogen electrode, anode electrode) and an oxygen electrode (air electrode, cathode electrode). Power generation is performed by electrochemically reacting a supplied fuel gas (for example, hydrogen) and an oxidant gas (for example, air) supplied to the oxygen electrode.

  A normal-pressure direct-injection-type fuel cell system (fuel cell device) that injects liquid water into the air electrode in the form of a mist for the purpose of cooling the oxygen electrode with an exothermic reaction and preventing the solid polymer electrolyte from drying and improving power generation performance. )

Japanese Unexamined Patent Publication No. 2001-210348 (Patent Document 1) describes such a direct fountain type fuel cell device. The fuel cell device described in Patent Document 1 detects a required load on the fuel cell in order to enhance the cooling effect of the air electrode, and controls the supply amount of process air supplied to the air electrode based on the detected required load. To do.
Japanese Patent Laid-Open No. 2001-210348

  By the way, in the direct fountain type fuel cell system, the required air amount increases as the required load on the fuel cell increases. However, since the amount of water generated at the air electrode increases, the air flow path becomes liquid during high load operation. It becomes easy to be blocked by water. When the air flow path is blocked with water, the amount of air supplied to the air electrode becomes insufficient, and the power generation performance deteriorates. Such a problem is particularly remarkable when the current collecting member for collecting current from the air electrode is formed of a porous body.

  The present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide a normal pressure direct fountain type fuel cell system capable of improving power generation performance during high load operation and an operation method thereof.

  In order to achieve this object, a fuel cell system according to claim 1 is a fuel cell comprising a solid polymer electrolyte membrane, and a fuel electrode and an oxygen electrode that sandwich the solid polymer electrolyte membrane from both sides; A fuel gas supply means for supplying fuel gas to the fuel electrode; an oxidant gas supply means for supplying oxidant gas to the oxygen electrode; and a nozzle for injecting liquid water in a mist form. Depending on the required load amount acquired by the water supply means for supplying the liquid water to the oxygen electrode by injection, the required load amount acquisition means for acquiring the required load amount for the fuel cell, and the required load amount acquisition means Water particle size changing means for adjusting the particle size of the liquid water ejected from the nozzle.

  The fuel cell system according to claim 2 is the fuel cell system according to claim 1, wherein the water particle size changing means has a required load quantity acquired by the required load quantity acquiring means larger than a first required load quantity. In the case of the second required load amount, the particle size of the liquid water ejected from the nozzle is set to be smaller than the particle size with respect to the first required load amount.

  A fuel cell system according to claim 3 is a fuel cell system according to claim 1 or 2, wherein the memory stores a relationship between a required load amount for the fuel cell and a particle size of liquid water ejected from the nozzle. And a size determination means for determining the particle size of the liquid water ejected from the nozzle based on the required load amount acquired by the required load amount acquisition means and the relationship stored in the size storage means. And the water particle size changing means sets the particle size of the liquid water ejected from the nozzle to the size determined by the size determining means.

  The fuel cell system according to claim 4 is the fuel cell system according to any one of claims 1 to 3, wherein the nozzle is a one-fluid nozzle that injects liquid water independently, The particle size can be changed according to the supply pressure of the liquid water supplied to the nozzle, and the water supply means further includes a water supply pump that pumps the liquid water to the nozzle, The water particle size changing means reduces the particle size of the liquid water ejected from the nozzle by increasing the supply voltage to the water supply pump.

  The fuel cell system according to claim 5 is the fuel cell system according to any one of claims 1 to 3, wherein the nozzle is a two-fluid nozzle that injects gas into liquid water and injects the gas. The particle size of the liquid water can be changed according to the supply pressure of the liquid water supplied to the nozzle and the supply pressure of the gas supplied to the nozzle, and the water supply means is connected to the nozzle. A water supply pump for pumping the liquid water; and an air supply pump for pumping a gas to the nozzle; and the water particle size changing means is configured to supply a supply voltage to the water supply pump and the air supply pump. By raising, the particle size of the liquid water ejected from the nozzle is reduced.

  An operating method according to claim 6 (operating method of a fuel cell system) is a fuel cell comprising a solid polymer electrolyte membrane and a fuel electrode and an oxygen electrode that sandwich the solid polymer electrolyte membrane from both sides; A fuel gas supply means for supplying a fuel gas to the fuel electrode; an oxidant gas supply means for supplying an oxidant gas to the oxygen electrode; and a nozzle for injecting liquid water in the form of a mist. A water supply means for supplying the liquid water to the oxygen electrode by jetting, a required load amount acquisition step for acquiring a required load amount for the fuel cell, and the request A water particle size changing step of adjusting the particle size of the liquid water ejected from the nozzle according to the required load amount acquired by the load amount acquisition means.

  According to the fuel cell system of claim 1, the solid polymer in which power is generated by the fuel gas supplied to the fuel electrode by the fuel gas supply means and the oxygen electrode supplied by the oxidant gas supply means to the oxygen electrode. A mist type liquid water is jetted from the nozzle to the oxygen electrode of such a polymer electrolyte fuel cell by water supply means.

  Here, the required load amount for the fuel cell is acquired by the required load amount acquisition means, and the particle size of the liquid water ejected from the nozzle is adjusted by the water particle size changing means according to the acquired required load amount. Is done.

  Therefore, since the particle size of the liquid water ejected from the nozzle is adjusted according to the required load amount, the particle size of the liquid water ejected from the nozzle can be reduced during high load operation. By reducing the particle size of the liquid water ejected from the nozzle during high load operation, it is possible to suppress blockage of the oxidant gas flow path to the oxygen electrode. The supply amount of the oxidizing gas that tends to be insufficient can be made a sufficient amount. Therefore, there is an effect that the power generation performance during high load operation can be improved.

  According to the fuel cell system of claim 2, in addition to the effect of the fuel cell system of claim 1, the following effect is obtained. When the required load amount acquired by the required load amount acquisition unit is the second required load amount larger than the first required load amount, the particle size of the liquid water ejected from the nozzle is changed to the water particle size changing unit. Therefore, the particle size of the liquid water ejected from the nozzle can be reduced as the required load increases.

  Therefore, the supply amount of the oxidant gas at the time of high load operation that tends to be insufficient due to the blockage of the flow path of the oxidant gas can be made a sufficient amount, and the power generation performance at the time of high load operation can be improved. There is an effect that can be done.

  According to the fuel cell system of claim 3, in addition to the effect of the fuel cell system of claim 1 or 2, the following effect is obtained. The relationship between the required load amount for the fuel cell and the particle size of the liquid water ejected from the nozzle is stored in the size storage means, and when the required load amount is acquired by the required load amount acquisition means, the required load Based on the amount and the relationship stored in the size storage means, the particle size of the liquid water ejected from the nozzle is determined by the size determining means, and the particle size of the liquid water ejected from the nozzle is changed to the water particle size changing means. Thus, the water particle size is set to the determined size.

  Therefore, the particle size of the liquid water ejected from the nozzle can be set to an optimum size according to the required load amount, and the blockage of the oxidant gas flow path during high load operation can be effectively suppressed. There is an effect that the power generation performance during the load operation can be improved.

  According to the fuel cell system of the fourth aspect, in addition to the effect produced by the fuel cell system according to any one of the first to third aspects, the following effect is produced. When the nozzle that sprays liquid water in the form of a mist on the oxygen electrode is a one-fluid nozzle that can freely change the particle size of the spray water according to the supply pressure of the liquid water supplied to the nozzle, the water particle size is changed. The means increases the supply voltage to the water supply pump to reduce the particle size of the liquid water ejected from the nozzle.

  Therefore, the supply voltage to the water supply pump can be kept low during low-load operation where the liquid water particle size can be relatively large. Therefore, there is an effect that overall power consumption in the fuel cell system can be suppressed.

  According to the fuel cell system of claim 5, in addition to the effect of the fuel cell system of any of claims 1 to 3, the following effect is obtained. A nozzle that sprays liquid water onto the oxygen electrode in the form of a mist can freely change the particle size of the spray water according to the supply pressure of the liquid water supplied to the nozzle and the supply pressure of the gas supplied to the nozzle In the case of the two-fluid nozzle, the water particle size changing means increases the supply voltage to the water supply pump and the air supply pump to reduce the particle size of the liquid water ejected from the nozzle.

  Therefore, the supply voltage to the water supply pump can be kept low during low-load operation where the liquid water particle size can be relatively large. Therefore, there is an effect that overall power consumption in the fuel cell system can be suppressed.

  According to the operation method (operation method of the fuel cell system) according to claim 6, for the fuel cell system in which mist liquid water is injected from the nozzle to the oxygen electrode of the solid polymer fuel cell by the water supply means, The required load amount for the fuel cell is acquired by the required load amount acquisition step, and the particle size of the liquid water ejected from the nozzle is adjusted by the water particle size changing step in accordance with the acquired required load amount.

  Therefore, since the particle size of the liquid water ejected from the nozzle is adjusted according to the required load amount, the particle size of the liquid water ejected from the nozzle can be reduced during high load operation. By reducing the particle size of the liquid water ejected from the nozzle during high-load operation, blockage of the oxidant gas flow path to the oxygen electrode can be suppressed, and the oxidant gas flow path blockage tends to be insufficient. In addition, the supply amount of the oxidant gas during the high load operation can be made a sufficient amount. Therefore, there is an effect that the power generation performance during high load operation can be improved.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a system diagram showing a first embodiment of a fuel cell system 100 which is a fuel cell system of the present invention.

  This fuel cell system 100 uses a fuel cell stack 40 and hydrogen gas as a fuel gas to form a fuel electrode (hydrogen electrode, anode electrode) 13 (for each unit cell 10 (see FIG. 4 and the like)) constituting the fuel cell stack 40 ( A hydrogen gas supply system 50 for supplying to the gas cell stack 40 and air as an oxidant gas are supplied to the air electrode (oxygen electrode, cathode electrode) 12 of each unit cell 10 constituting the fuel cell stack 40 (see FIG. 4). ) And a water supply system 80 for supplying the mist liquid water to the air electrode 12 of the fuel cell stack 40 to cool and wet the unit cell 10.

  The fuel cell stack 40 includes a unit cell 10 as a fuel cell (see FIG. 4 and the like) and a separator 20 (see FIG. 4 and the like) that is interposed between the adjacent unit cells 10 and electrically connects the adjacent unit cells 10. In the thickness direction of the unit cell 10 and the separator 20. The fuel cell stack (each unit cell 10) corresponds to a fuel cell constituting the fuel cell system of the present invention.

  An air manifold 41 for introducing air into the air flow path of the fuel cell stack 40 is provided on the upstream side of the air flow path (not shown) in the fuel cell stack 40. On the other hand, an exhaust manifold 42 and a condenser 43 are provided on the downstream side of the air flow path. Excess air passes through the exhaust manifold 42 and condenses and removes moisture in the condenser 43, and then exhausts not shown. Exhausted into the atmosphere through the mouth.

  The hydrogen gas supply system 50 includes a hydrogen cylinder 51 serving as a hydrogen source and adjustment valves 52 to 56 for adjusting the flow rate of the hydrogen gas supplied from the hydrogen cylinder 51, and is not shown in the fuel cell stack 40. Connected to the gas flow path, hydrogen gas is supplied to the hydrogen gas flow path. The hydrogen gas supply system 50 further includes a pump 58 and a circulation valve 57 so that unreacted hydrogen gas discharged from the fuel cell stack 40 can be returned to the hydrogen gas supply flow path and circulated. It is configured. The hydrogen gas supply system 50 corresponds to a fuel gas supply means constituting the fuel cell system of the present invention.

  The air supply system 60 is configured to include a blower 61 such as a sirocco fan or a turbofan, and a supply pipe 62 connected to the air manifold 41, and external air taken in by the blower 61 is supplied to the supply pipe 62 and the air manifold 41. To the air flow path of the fuel cell stack 40. Therefore, the fuel cell system 100 of the present embodiment is a system that supplies atmospheric pressure air (oxidant gas) to the fuel cell stack 40. The air supply system 60 corresponds to an oxidant gas supply means constituting the fuel cell system of the present invention.

  The water supply system 80 includes a water tank 81 that stores water, a nozzle 82 disposed in the air manifold 41, and a water supply pump 83 that pumps water from the water tank 81 to the nozzle 82. The stored water is jetted from the nozzle 82 to the air manifold 41. The water injected to the air manifold 41 is made into a mist by the air flow flowing through the air supply system 60 and sent to the fuel cell stack 40. The water supply system 80 corresponds to the water supply means constituting the fuel cell system of the present invention.

  The nozzle 82 used in the fuel cell system 100 of this embodiment is a one-fluid nozzle that independently injects water (liquid water) pumped from the water supply pump 83. The nozzle 82 is configured such that the particle size (for example, the average particle diameter) of water to be ejected changes according to the water pressure (supply pressure) of water supplied from the water supply pump 83. Specifically, the nozzle 82 is configured such that the particle size of the water to be ejected decreases as the supply pressure of the water supplied to the nozzle 82 increases.

  A pump 84 is provided between the water tank 81 and the condenser 43, and the moisture condensed in the condenser 43 is sent to the water tank 81 to be reused as moisture for wetting the fuel cell stack 40. It is configured to be used.

  When operating the fuel cell system 100 configured as described above, the blower 61 of the air supply system 60 is driven to supply air from the air manifold 41 into the air flow path of the fuel cell stack 40, and Water is supplied by driving the water supply pump 83 of the water supply system 80. On the other hand, the adjustment valves 52 to 56 of the hydrogen gas supply system 50 are adjusted and supplied into the hydrogen gas flow path of the fuel cell stack 40 as a predetermined pressure.

  As a result, a water generation reaction (electrode reaction) between hydrogen and oxygen is performed in each fuel cell 10 constituting the fuel cell stack 40, and the generated current flows to the load 90. During operation of the fuel cell system 100, each fuel cell 10 is cooled and humidified by water supplied in the form of a mist.

  Furthermore, the fuel cell system 100 of this embodiment includes a control device 70 that controls the operation of the fuel cell system 100. The control device 70 includes a CPU 71 that is a central processing unit, a ROM 72 that is a non-rewritable nonvolatile memory storing a control program executed by the CPU 71, fixed value data, and the like, and various data when the control program is executed. The rewritable RAM 73 mainly includes a CPU 71, a ROM 72, and an input / output port 75 connected to the RAM 73 via a bus line 74.

  Here, in the fuel cell system 100 of the present embodiment, the input / output port 75 of the control device 70 is connected to the water supply pump 83 of the water supply system 80. Although details will be described later, the control device 70 of the fuel cell system 100 according to the present embodiment is a liquid that is ejected from the nozzle 82 based on a load input amount (required load amount) determined by an accelerator opening degree, a traveling speed, and the like. The optimum particle size of water is determined, and the voltage control value to the feed water pump 83 necessary to obtain the optimum particle size is appropriately changed.

  Therefore, according to the fuel cell system 100 of the present embodiment, the particle size of the liquid water ejected from the nozzle 82 can be reduced during high load operation, so that the air channel can be prevented from being blocked by water. Even during high load operation, a sufficient amount of air can be supplied to each air electrode 12 (see FIG. 4) of the fuel cell stack 40. Therefore, the fuel cell system 100 with improved power generation performance during high load operation can be obtained.

  In addition, although connection etc. are not shown in figure, the control apparatus 70 is the flow volume and temperature of the gas (hydrogen gas and air) supplied to the fuel cell stack 40 detected by various sensors besides the control mentioned above, or, Fuel such as control of the blower 61 in the air supply system 60, control of the regulating valves 52 to 56, the pump 58, the circulation valve 57, etc. in the hydrogen gas supply system 50 based on the output voltage from the fuel cell stack 40, etc. Various controls for operating the electronic system 100 are performed.

  Next, the configuration of the fuel cell stack 40 will be described with reference to FIGS. FIG. 2A is a top view schematically showing the fuel cell stack 40 in the present embodiment, and FIG. 2B is a top view schematically showing the cell module 30 constituting the fuel cell stack 40. is there. In FIG. 2A, two cell modules 30 are shown as representatives, and the other cell modules 30 are not shown. Further, in FIG. 2B, only the positional relationship between the unit cell 10 and the separator 20 is illustrated for the purpose of facilitating understanding, and a specific configuration is omitted.

  FIG. 3A is a front view of the cell module 30 viewed from the air electrode side, and FIG. 3B is a front view of the cell module 30 viewed from the fuel electrode side. 4A is a cross-sectional view taken along the arrow IVa-IVa in FIG. 3A, and FIG. 4B is a cross-sectional view taken along the arrow in FIG.

  As shown in FIG. 2A, the fuel cell stack 40 in the present embodiment is configured by stacking a plurality of cell modules 30.

  As shown in FIG. 2B, the cell module 30 includes a unit cell 10 and a separator 20 that is interposed between the adjacent unit cells 10 and electrically connects the adjacent unit cells 10 to each other. 10 and frames 17 and 18 that support the separator 20 are set as one set, and a plurality of sets are laminated in the thickness direction. In addition, the cell module 30 illustrated in FIG. 2B is obtained by laminating 10 sets each including the unit cell 10 and the separator 20.

  In the cell module 30, unit cells 10 and separators 20 are stacked in multiple stages using two types of frames 17 and 18 alternately as spacers so that adjacent unit cells 10 are arranged at a predetermined interval. Are stacked.

  One end of the cell module 30 in the stacking direction (the upper end surface side in FIG. 2A) terminates at the end surface of the air electrode side collector 22 of the separator 20 and the end surface of the frame 17 as shown in FIG. ing. On the other hand, the other end of the cell module 30 in the stacking direction (the lower end face side in FIG. 2A) is the end face of the fuel electrode side collector 23 of the separator 20 and the end face of the frame 18, as shown in FIG. And terminated with.

  As shown in FIG. 4A and FIG. 4B, the unit cell 10 includes a solid polymer electrolyte membrane 11, an air electrode 12 in contact with one surface of the solid polymer electrolyte membrane 11, a solid height The fuel electrode 13 is in contact with the other surface of the molecular electrolyte membrane 11.

  Examples of the solid polymer electrolyte membrane 11 include solid polymer electrolyte membranes applicable to solid polymer fuel cells such as Nafion (registered trademark: manufactured by DuPont) and Aciplex (registered trademark: manufactured by Asahi Kasei Co., Ltd.). Can be used.

  The air electrode 12 is formed on a diffusion layer (not shown) made of a conductive material that permeates while diffusing air (oxidant gas), and is in contact with the solid polymer electrolyte membrane 11. And a reaction layer (not shown).

  The fuel electrode 13 is formed on a diffusion layer (not shown) made of a conductive material that permeates while diffusing hydrogen gas (fuel gas), and is in contact with the solid polymer electrolyte membrane 11. And a reaction layer (not shown).

  The diffusion layer constituting the air electrode 12 and the fuel electrode 13 is composed of carbon woven fabric, carbon paper, etc. capable of gas diffusion, for example, carbon cloth, carbon paper, carbon fiber. The nonwoven fabric etc. which become can be used. In addition, as the reaction layer constituting the air electrode 12 and the fuel electrode 13, for example, a reaction layer (catalyst layer) configured to include carbon carrying a platinum catalyst and PTFE (polytetrafluoroethylene) is employed. can do.

  Among the members constituting the unit cell 10, the air electrode 12 and the fuel electrode 13 have a lateral dimension slightly longer than the lateral dimension (short dimension) of the opening of the frame 18 serving as a supporting member thereof, and the opening. The vertical dimension (longitudinal dimension) is slightly longer than the vertical dimension. Further, the solid polymer electrolyte membrane 11 has a vertical and horizontal dimension that is slightly larger than the vertical and horizontal dimensions of the opening.

  The separator 20 is provided on one side of the separator body 21, the air electrode side collector 22 that is in contact with the diffusion layer (not shown) of the air electrode 12 of the unit cell 10, and the separator body 21. And a fuel electrode side collector 23 which is provided on the other side and abuts against a diffusion layer (not shown) of the fuel electrode 13 of the unit cell 10.

  The separator body 21 is a thin metal plate that functions as a gas blocking member between adjacent unit cells 10. Examples of the metal constituting the separator body 21 include a metal having conductivity and corrosion resistance, for example, a stainless steel, a nickel alloy, a titanium alloy and the like subjected to a corrosion-resistant conductive treatment such as gold plating.

  The air electrode side collector 22 is in contact with the air electrode 12 and collects current, and is also a conductive member having a large number of holes that enables supply of air to the air electrode 12 and discharge of generated water from the air electrode 12. It is. Moreover, the air electrode side collector 22 functions also as a heat sink, and is cooled by the water injected from the nozzle 82 (refer FIG. 1) of the water supply system 80. FIG. The detailed configuration of the air electrode side collector 22 will be described later with reference to FIG.

  The fuel electrode-side collector 23 is a conductive member that contacts the fuel electrode 13 and collects current and has a large number of holes that enable supply of hydrogen gas to the fuel electrode 13. In addition, since this fuel electrode side collector 23 can be comprised similarly to the air electrode side collector 22, detailed description is abbreviate | omitted.

  Frames 17 and 18 are arranged outside the separator 20 so that the unit cell 10 can be held in a predetermined positional relationship. These frames 17 and 18 are made of an insulating material.

  More specifically, the frames 17 are arranged on the left and right sides of the air electrode side collector 22, and the frame 18 is provided on the peripheral edge of the fuel electrode side collector 23. As shown in FIG. 3, the uppermost and lower ends of the frame 17 arranged at the outermost end are connected to each other by backup plates 17a and 17b to form a frame shape.

  As shown in FIGS. 4A and 4B, the frame 17 disposed on the air electrode side collector 22 side has an outer end (the uppermost end in FIG. 4A and the left end in FIG. 4B). The vertical frame portions 171 are arranged on both sides along the short side of the air electrode side collector 22 except for those arranged on the air electrode side collector 22. The thickness of the frame 17 is comparable to the thickness of the air electrode side collector 22.

  The vertical frame portion 171 is provided with a long hole 172 penetrating in the thickness direction for forming a hydrogen gas flow path. The vertical and horizontal dimensions on the surface of the separator body 21 are comparable to the vertical and horizontal dimensions on the surface of the frame 17, and the same long hole 212 is provided at a position overlapping the long hole 172 of the frame 17. Yes.

  With the arrangement of the frame 17, an air chamber surrounded by the air electrode 12 of the unit cell 10 and the separator body 21 is formed between the left and right vertical frame portions 171. Although details will be described later, a plurality of linear rib members 222 (a part of the air electrode side collector 22) extending in the direction perpendicular to the paper surface in FIG. In addition, the installation of the rib member 222 forms an air flow path that passes all the way in one direction (the direction perpendicular to the paper surface in FIG. 4A).

  On the other hand, as shown in FIG. 4B, the frame 18 surrounding the fuel electrode side collector 23 and the unit cell 10 is a frame-shaped member having left and right vertical frame portions and upper and lower horizontal frame portions 182 and is configured in a frame shape. The size of the frame 17 is the same as that of the frame 17 (FIG. 3A). The left and right vertical frame portions of the frame 18 are not shown because they are located further to the right than the description range of FIG. 4A, but both sides are located at the same positions as the left and right side ends of both the vertical frame portions 171 of the frame 17. The length (width) in the short direction is substantially the same as the length in the short direction of the upper and lower horizontal frame portions 182.

  As shown in FIG. 4A, the frame 18 is parallel to the left and right vertical frame portions except for the frame 18 arranged at the outer end (the bottom end in FIG. 2B, the surface shown in FIG. 3B). The thin plate-like backup plate 18a and the thick plate-like backup plate 18b extend and overlap the left and right ends of the fuel electrode side collector 23 (end portions in the left and right direction in FIG. 4A). The thickness of the frame 18 is comparable to the thickness of the fuel electrode side collector 23.

  A space surrounded by the backup plate 18a and the vertical frame portion 171 constitutes a space for forming a hydrogen gas flow path together with the long hole 172 penetrating the frame 17 in the plate thickness direction. A fuel chamber surrounded by the fuel electrode 13 of the unit cell 10 and the separator body 21 is formed on the inner peripheral side of each frame 18.

  In this fuel chamber, a linear rib member 232 (fuel electrode side collector) extending in a direction orthogonal to the rib member 222 (that is, a direction perpendicular to the paper surface in FIG. 4B and a horizontal direction in FIG. 4A). 23) are standing upright in parallel. The installation of the rib member 232 forms a hydrogen gas flow path that passes completely in the direction perpendicular to the air flow path described above (the direction perpendicular to the paper surface in FIG. 4B).

  Next, a detailed configuration of the air electrode side collector 22 will be described with reference to FIG. FIG. 5A is a front view of the air electrode side collector 22 viewed from the separator body 21 side, and FIG. 5B is a side view of the air electrode side collector 22 viewed from the Vb direction in FIG. 5A and 5B, illustration of the holes 221a and 221b opened in the base collector 221 is omitted.

  As shown in FIGS. 5A and 5B, the air electrode side collector 22 of the present embodiment includes a base collector 221 and a plurality of rib members 222.

  The base collector 221 is a conductive plate that is brought into contact with the air electrode 12 of the unit cell 10 and collects current from the air electrode 12. The base collector 221 is manufactured from a metal having conductivity and corrosion resistance, such as stainless steel, nickel alloy, titanium alloy or the like subjected to corrosion resistance conductive treatment such as gold plating.

  The base collector 221 is composed of a porous body having a large number of holes, for example, an expanded metal or a punching metal. In addition, although the shape of the hole opened to the base collector 221 is not illustrated in the present embodiment, for example, a rhombus, a square, a hexagon, a circle, or the like can be appropriately employed.

  When the hole opened in the base collector 221 has a rhombus shape, for example, the shorter diagonal dimension is about 0.7 mm to about 1.3 mm, and the longer diagonal dimension is about 0 mm. It can be designed to be about 8 mm to about 2.8 mm. Moreover, it is preferable that the aperture ratio of the hole opened to the base collector 221 is about 30 to about 50%.

  On the other hand, as shown in FIGS. 5A and 5B, each of the plurality of rib members 222 is a linear body having a rectangular cross section, and these rib members 222 are formed of the base collector 221. Are arranged in a state of being arranged substantially parallel to each other on the surface opposite to the contact surface with the air electrode 12. The rib member 222 is bonded to the surface of the base collector 221 by, for example, diffusion bonding.

  Thus, the rib member 222 erected on the base collector 221 is inserted between the base collector 221 and the separator body 21 in the air electrode side collector 22 to form an air flow path (air chamber). Create a space.

  In order to realize high-efficiency power generation in the fuel cell and suppress power loss of the auxiliary equipment, it is preferable to reduce the air flow resistance of the air flow path as much as possible. Therefore, it is necessary to appropriately secure the height of the flow path for supplying air to the unit cell 10, that is, the height of the rib member 222, while reducing the size of the fuel cell stack 40, that is, the cell module 30. In order to reduce the size, the height of the rib member 222 is preferably as low as possible. Therefore, the height dimension of the rib member 222 is set to a height that satisfies both of these conditions, for example, about 0.5 mm to about 0.9 mm.

  The rib member 222 is made of a metal having conductivity and corrosion resistance. In addition, the material (material) which comprises the rib member 222 may be the same material as the base collector 221 mentioned above, or a different material. Further, the cross-sectional shape of the rib member 222 is not limited to the rectangular shape illustrated in FIG. 5B, and may be other shapes such as a triangle or a circle.

  The fuel electrode side collector 23 can also be configured in the same manner as the air electrode side collector 22. That is, if the fuel electrode side collector 23 is composed of a base collector 231 corresponding to the base collector 221 (see FIG. 4B) and a rib member 232 corresponding to the rib member 222 (see FIG. 4B). Good.

  Next, with reference to FIGS. 6 and 7, the control according to the required load amount for the fuel cell in the fuel cell system 100 having the above-described configuration will be described. FIG. 6A is a schematic diagram showing the content of a required load amount-particle size map 72a showing the relationship between the required load amount and the particle size of water (liquid water) ejected from the nozzle 82. FIG. b) is a schematic diagram showing the content of a water supply pump water pressure-particle size map 72b showing the relationship between the water pressure (supply pressure) of the water supply pump 83 and the particle size of water sprayed from the nozzle 82. FIG.

  As shown in FIG. 6A, the required load amount-particle size map 72a is liquid water ejected from the nozzle 82 with respect to the required load amount (load input amount) determined by the accelerator opening degree, the traveling speed, and the like. This map correlates the optimum particle size and is used in the operation control process (FIG. 7). The required load amount-particle size map 72a is stored in the ROM 72 in the control device 70, and is created based on, for example, a value obtained by a preliminary experiment.

  In the required load amount-particle size map 72a, the horizontal axis is an axis indicating the required load amount for the fuel cell stack 40 (each unit cell 10), and indicates that the required load amount is larger toward the right side. . On the other hand, the vertical axis is an axis indicating the optimum particle size (unit: μm) as the liquid water ejected from the nozzle 82, and indicates that the particle size increases toward the upper side. Here, the range of the optimum particle size as the liquid water ejected from the nozzle 82 in the required load amount-particle size map 72a is set to about 10 μm to about 100 μm in this embodiment.

  As shown in FIG. 6A, according to the required load amount-particle size map 72a, the optimum particle size that is optimal as the liquid water ejected from the nozzle 82 is smaller as the required load amount is larger. Therefore, in the operation control process (FIG. 7) described later, the smaller the required load amount, the smaller the particle size is selected.

  On the other hand, as shown in FIG. 6B, the feed water pump water pressure-particle size map 72 b is a map showing the correlation between the water pressure (supply pressure) of the feed water pump 83 and the particle size of liquid water ejected from the nozzle 82. And used in the operation control process (FIG. 7). The water supply pump water pressure-particle size map 72b is stored in the ROM 72 in the control device 70, and is created based on, for example, a value obtained by a preliminary experiment, a product catalog of the nozzle 82, or the like.

  In the feed water pressure-particle size map 72b, the horizontal axis is an axis indicating the water pressure of the feed water pump 83, and the water pressure of the feed water pump 83 is higher toward the right side. On the other hand, the vertical axis is an axis indicating the optimum particle size (unit: μm) as the liquid water ejected from the nozzle 82, and indicates that the particle size increases toward the upper side.

  As shown in FIG. 6B, according to the feed water pump water pressure-particle size map 72b, the particle size of the liquid water ejected from the nozzle 82 can be reduced as the water pressure of the feed water pump 83 is increased. In the present embodiment, the maximum value of the water pressure of the water supply pump 83 in the water supply pump water pressure-particle size map 72b is set to about 5 MPa.

In the fuel cell system 100 of the present embodiment, the control device 70 calculates the required load amount from the accelerator opening degree, the traveling speed, and the like, and uses the required load amount-particle size map 72a to calculate the required load amount. Determining the optimum particle size of the liquid water ejected from the nozzle 82, then obtaining the water pressure of the feed water pump 83 for injecting the liquid water of the determined particle size from the feed water pump water pressure-particle size map 72b; The water pressure of the feed water pump 83 is controlled.
As described above, according to the required load amount-particle size map 72a, the smaller the required load amount, the smaller the particle size selected. Therefore, according to the feed water pressure-particle size map 72b, the required load The larger the amount is (the higher the load operation is), the smaller the particle size of liquid water is jetted from the nozzle 82 in the form of a mist.

  FIG. 7 is a flowchart showing an operation control process executed in the control device 70. This operation control process is a process for controlling the operation of the fuel cell system 100, and is repeatedly executed periodically by the CPU 71 while the power of the control device 70 is turned on. A control program for executing this operation control process is stored in the ROM 72.

  As shown in FIG. 7, in this operation control process, first, a required load amount is calculated based on an accelerator opening degree, a traveling speed, and the like acquired from a sensor device (not shown) (S11). This S11 corresponds to the required load amount acquisition means in the fuel cell system of the present invention and also corresponds to the required load amount acquisition step in the operating method of the fuel cell system of the present invention.

  After the process of S11, the optimum air volume corresponding to the calculated required load is acquired (S12). Note that the optimum air volume corresponding to the required load is stored in the ROM 12 as a map (not shown) in which these parameters are associated with each other, and is acquired based on the map. In addition, you may comprise so that the optimal airflow may be acquired based on the function which linked | related the optimal airflow with respect to request | requirement load amount.

  After the process of S12, the voltage control value of the blower 61 for obtaining the acquired optimum air volume is acquired (S13), and the acquired voltage control value is output to the blower 61 (S14). As a result of the processing of S14, the air volume (air volume) of the blower 61 is adjusted so as to be an optimum air volume according to the required load amount for the fuel cell stack 40.

  After the process of S14, the optimal particle size (optimum particle size) of the liquid water ejected from the nozzle 82 is acquired based on the required load amount acquired by the process of S11 (S15). In the present embodiment, the optimum particle size is acquired using the required load amount-particle size map 72a. Therefore, the smaller the required load amount, the smaller the particle size is acquired as the optimum particle size. This S15 corresponds to the size determining means in the fuel cell system of the present invention.

  After the process of S15, the voltage control value of the water supply pump 83 necessary to obtain the acquired optimum particle size is acquired (S16). Specifically, using the feed water pressure-particle size map 72b, the water pressure of the feed water pump 83 necessary for injecting the liquid water having the optimum particle size from the nozzle 82 is obtained, and the obtained water pressure is obtained. The voltage control value of the feed water pump 83 is acquired. Therefore, the smaller the optimum particle size (that is, the greater the required load amount), the greater the water pressure of the feed water pump 83, and the greater the voltage control value of the feed water pump 83.

  After the process of S16, the acquired voltage control value is output to the feed water pump 83 (S17). As a result of the processing of S17, the water pressure (supply pressure) of the water supply pump 83 is adjusted so that the particle size of the liquid water ejected from the nozzle 82 becomes the optimum particle size according to the required load amount for the fuel cell stack 40. The In addition, S15-S17 mentioned above corresponds to the water particle size change means in the operation method of the fuel cell system of this invention while it corresponds to the water particle size change means in the fuel cell system of this invention.

  After the process of S17, a hydrogen supply amount control process for controlling the hydrogen supply quantity to the hydrogen electrode 13 is executed (S18), and this operation control process is terminated. Note that the hydrogen supply amount control process is not the gist of the present invention, and therefore will be omitted.

  Here, with reference to FIG. 8, the effect obtained by changing the particle size of the liquid water ejected from the nozzle 82 according to the required load will be described. FIG. 8 is a graph schematically showing the relationship between the required load amount and the substantial air supply amount (substantial air supply amount) supplied to the air electrode 12. In FIG. 8, the horizontal axis is an axis indicating the required load amount with respect to the fuel cell stack, and indicates that the required load amount is larger toward the right side. On the other hand, the vertical axis is an axis that indicates a substantial amount of air supplied to the air electrode 12, and indicates that the amount of air that is substantially supplied to the air electrode 12 increases toward the upper side.

  In FIG. 8, a solid line A indicates a case where the fuel cell system 100 of the present embodiment that changes the particle size of the liquid water ejected from the nozzle 82 in accordance with the required load amount, and a broken line B indicates the required load amount. The case where the fuel cell system which does not change the particle size of the liquid water ejected from the nozzle 82 in accordance with is shown.

  As shown in FIG. 8, when the particle size of the liquid water ejected from the nozzle 82 is not changed according to the required load amount (broken line B), substantial air supply to the air electrode 12 during high load operation. Whereas the amount is relatively low, when the fuel cell system 100 of the present embodiment is used (solid line A), the substantial air supply amount to the air electrode 12 is improved even during high load operation. The

  The air volume of the blower 61 controlled by the processes of S12 to S14 in the operation control process (see FIG. 7) is increased as the required load amount on the fuel cell stack 40 is larger. On the other hand, the water pressure of the water supply pump 83 controlled by the processes of S15 to S17 is increased as the required load on the fuel cell stack 40 increases. Therefore, both the amount of air and the amount of water supplied to the air electrode 12 increase as the required load amount on the fuel cell stack 40 increases.

  Therefore, during a high load operation, the amount of water supplied to the air electrode 12 and the amount of water generated at the air electrode 12 increase even though a large amount of air supplied to the air electrode 12 is required for power generation. The flow path, in particular, the hole opened in the base collector 221 of the air electrode side collector 22 is easily clogged with liquid water, and the amount of air that can be substantially supplied to the air electrode 12 tends to be insufficient. .

  However, according to the fuel cell system 100 of the present embodiment, the feed water pump 83 is controlled such that the larger the required load amount on the fuel cell stack 40, the smaller the particle size of the liquid water ejected from the nozzle 82. Therefore, blockage of the air flow path (oxidant gas flow path) to the oxygen electrode 12 due to the jetted liquid water can be suppressed. Therefore, since a sufficient amount of air can be supplied to the air electrode 12 even during high load operation (when the required load amount is large), the power generation performance during high load operation can be improved.

  Next, a second embodiment will be described with reference to FIGS. In the first embodiment described above, the nozzle 82 that is a one-fluid nozzle is used as the nozzle that sprays liquid water to the air electrode 12 in the form of a mist. In the second embodiment, however, the nozzle 182 that is a two-fluid nozzle is used. use. In addition, the same code | symbol is attached | subjected to the part same as above-described 1st Embodiment, and the description is abbreviate | omitted.

  FIG. 9 is a system diagram showing a fuel cell system 500 of the second embodiment. The fuel cell system 500 of the second embodiment also corresponds to the fuel cell system of the present invention.

  As shown in FIG. 9, in the fuel cell system 500 of the second embodiment, a water supply system 800 corresponding to the water supply system 80 of the first embodiment is arranged in a water tank 81, a pump 84, and an air manifold 41. A nozzle 182 that is a two-fluid nozzle, a water supply pump 83 that pumps water from the water tank 81 to the nozzle 182, and a gas pump 85 that pumps air taken in from the outside by a device (not shown) to the nozzle 182. It is configured.

  The water supply system 800 injects water stored in the water tank 81 from the nozzle 182 to the air manifold 41. The water injected to the air manifold 41 is made into a mist by the air flow flowing through the air supply system 60 and sent to the fuel cell stack 40.

  The nozzle 182 is a two-fluid nozzle that mixes and injects the air pumped from the feed pump 85 to the water pumped from the feed pump 83 (liquid water). The nozzle 182 changes the particle size of water to be ejected according to the water pressure (supply pressure) of water supplied from the water supply pump 83 and the pressure of air supplied from the air supply pump 85 (supply pressure). It is configured. Specifically, the nozzle 182 is configured such that the particle size of water to be ejected decreases as at least one of the supply pressure of water supplied to the nozzle 182 or the supply pressure of air increases.

  The input / output port 75 of the control device 70 in the second embodiment is connected to the water supply pump 83 and the air supply pump 85 of the water supply system 800. As will be described later, the control device 70 of the fuel cell system 500 according to the present embodiment is configured so that the liquid water ejected from the nozzle 182 is based on a load input amount (required load amount) determined by an accelerator opening, a traveling speed, and the like. The optimum particle size is determined, and the control voltage value of the water supply pump 83 and the control voltage value of the air supply pump 85 necessary for obtaining the optimum particle size are appropriately changed.

  Further, the ROM 72 of the control device 70 in the second embodiment stores a feed water pump water pressure-particle size map 72c and a feed air pump pressure-particle size map 72d instead of the feed water pump water pressure-particle size map 72b. ing. The required load amount-particle size map 72a is stored in the ROM 72 as in the first embodiment.

  Here, FIG. 10A is a schematic diagram showing the content of the feed water pump water pressure-particle size map 72c, and FIG. 10B is a schematic diagram showing the content of the feed air pump pressure-particle size map 72d. is there.

  As shown in FIG. 10A, the feed water pump water pressure-particle size map 72 c is a map showing the correlation between the water pressure (supply pressure) of the feed water pump 83 and the particle size of liquid water ejected from the nozzle 82. , Used in the operation control process (FIG. 11) of the second embodiment. The water supply pump water pressure-particle size map 72c is created based on, for example, a value obtained by a preliminary experiment, a product catalog of the nozzle 182 or the like.

  In the feed water pressure-particle size map 72c, the horizontal axis is an axis indicating the water pressure of the feed water pump 83, and the water pressure of the feed water pump 83 is higher toward the right side. On the other hand, the vertical axis is an axis indicating the optimum particle size (unit: μm) as the liquid water ejected from the nozzle 182 and indicates that the particle size increases toward the upper side.

  As shown in FIG. 10A, according to the water supply pump water pressure-particle size map 72c, the particle size of the liquid water ejected from the nozzle 182 can be reduced as the water pressure of the water supply pump 83 is increased. In the second embodiment, the maximum value of the water pressure of the water supply pump 83 in the water supply pump water pressure-particle size map 72c is set to about 0.2 MPa.

  On the other hand, as shown in FIG. 10B, the air supply pump water pressure-particle size map 72d includes the pressure of the air pumped from the air supply pump 85 (supply pressure) and the particle size of the liquid water ejected from the nozzle 182. These maps are used in the operation control process (FIG. 11) of the second embodiment. The air supply pump pressure-particle size map 72d is created based on, for example, a value obtained by a preliminary experiment, a product catalog of the nozzle 182 or the like.

  In the air supply pump pressure-particle size map 72d, the horizontal axis is an axis indicating the pressure of the air pumped from the air supply pump 85, and the pressure of the air supplied from the air supply pump 83 is increased toward the right side. Is high. On the other hand, the vertical axis is an axis indicating the optimum particle size (unit: μm) as the liquid water ejected from the nozzle 182 and indicates that the particle size increases toward the upper side.

  As shown in FIG. 10B, according to the air supply pump pressure-particle size map 72d, the particle size of the liquid water ejected from the nozzle 182 increases as the pressure of the air pumped from the air supply pump 85 increases. Can be small. In the present embodiment, the maximum value of the supply pressure of the supply pump 85 in the supply pump pressure-particle size map 72d is set to about 0.2 MPa.

  In the fuel cell system 500 of the present embodiment, the control device 70 calculates the required load amount from the accelerator opening, the traveling speed, and the like, and uses the required load amount-particle size map 72a to calculate the required load amount. The optimum particle size of the liquid water ejected from the nozzle 182 is determined, and then the supply pressure of the water supply pump 83 and the air supply pump 85 for injecting the liquid water of the determined particle size is respectively determined as the water supply pump water pressure. -Particle size map 72c and air supply pump water pressure-Obtained from the particle size map 72d and control the water pressure of the water supply pump 83 and the pressure of the air pumped from the air supply pump 85.

  As described above, according to the required load amount-particle size map 72a, the smaller the required load amount, the smaller the particle size selected. Therefore, the feed water pressure-particle size map 72c, the supply pump pressure-particles According to the size map 72d, the larger the required load amount (the higher the load operation), the smaller the particle size of liquid water is sprayed from the nozzle 182.

  FIG. 11 is a flowchart showing an operation control process in the second embodiment. This operation control process is a process for controlling the operation of the fuel cell system 500, similar to the fuel cell system 100 of the first embodiment, and is periodically performed by the CPU 71 while the control device 70 is powered on. Repeatedly. A control program for executing this operation control process is stored in the ROM 72.

  As shown in FIG. 11, in this operation control process, first, a required load amount is calculated based on an accelerator opening degree, a traveling speed, and the like acquired from a sensor device (not shown) (S11), and the calculated required load amount is calculated. Is acquired (S12), the voltage control value of the blower 61 for obtaining the acquired optimal airflow is acquired (S13), and the acquired voltage control value is output to the blower 61 (S14).

  After the process of S14, the optimal particle size (optimum particle size) of the liquid water ejected from the nozzle 182 is acquired based on the required load amount acquired by the process of S11 (S15). Also in the second embodiment, as in the first embodiment, the optimum particle size is acquired using the required load amount-particle size map 72a. Therefore, the smaller the required load amount, the smaller the particle size is acquired as the optimum particle size.

  After the process of S15, the voltage control value of the water supply pump 83 necessary for obtaining the acquired optimum particle size is acquired (S16), and the acquired voltage control value is output to the water supply pump 83 (S17). In the second embodiment, the water pressure of the water supply pump 83 required for injecting the liquid water having the optimum particle size from the nozzle 182 is determined using the water supply pump water pressure-particle size map 72c (see FIG. 10A). The voltage control value of the feed water pump 83 for obtaining and obtaining the obtained water pressure is obtained.

  After the process of S17, the voltage control value of the air supply pump 85 necessary for obtaining the optimum particle size acquired by the process of S15 is acquired (S21), and the acquired voltage control value is output to the air supply pump 85 ( S22) A hydrogen supply amount control process is executed (S18), and the operation control process is terminated.

  In the process of S21, supply of the air supply pump 85 necessary for injecting the liquid water having the optimum particle size from the nozzle 182 using the air supply pump pressure-particle size map 72d (see FIG. 10B). The pressure is acquired, and the voltage control value of the air supply pump 85 for obtaining the acquired supply pressure is acquired.

  As a result of the processing of S17 and S22, the water pressure (supply pressure) of the water supply pump 83 and the supply pressure of the air supply pump 85 are determined so that the particle size of the liquid water ejected from the nozzle 182 depends on the required load amount for the fuel cell stack 40. Adjusted to the optimum particle size. Note that S15 to S17, S21, and S22 described above correspond to the water particle size changing means in the fuel cell system of the present invention, and also correspond to the water particle size changing step in the operating method of the fuel cell system of the present invention.

  Therefore, according to the fuel cell system 500 of the second embodiment, the larger the required load amount to the fuel cell stack 40 is, the larger the required load amount is injected from the nozzle 182, as in the fuel cell system 100 of the first embodiment described above. Since the water supply pump 83 and the air supply pump 85 are controlled so that the particle size of the liquid water is reduced, the blocking of the air flow path (oxidant gas flow path) to the oxygen electrode 12 by the injected liquid water is suppressed. can do. Therefore, a sufficient amount of air can be supplied to the air electrode 12 even during high load operation (when the required load amount is large), and power generation performance during high load operation can be improved.

  In addition, since the nozzle 182 used in the fuel cell system 500 of the second embodiment is a two-fluid nozzle that uses the pressure of air, there is an advantage that it is easy to obtain a pressure for pumping liquid water. On the other hand, since the nozzle 82 used in the fuel cell system 100 of the first embodiment is a one-fluid nozzle that independently injects liquid water pumped from the water supply pump 83, the air supply pump 85 and the like are not required. This is advantageous for downsizing the system configuration and has the advantage that the power consumption can be suppressed by the amount that the air supply pump 85 and the like are unnecessary.

  As described above, according to the embodiments, according to the fuel cell systems 100 and 500 and the operation method (operation control process) of the present invention, the liquid water ejected from the nozzles 82 and 182 increases as the required load amount increases. Therefore, the air supply amount at the time of high load operation, which tends to be insufficient due to the blockage of the air flow path with the increase in the supply amount of the liquid water, can be made a sufficient amount. As a result, the power generation performance during high load operation can be improved.

  According to the fuel cell systems 100 and 500 of the above embodiments, the relationship between the required load amount for the fuel cell stack 40 and the particle size of the liquid water ejected from the nozzles 82 and 182 is ROM 72 (required load amount−particles. Since it is stored in the size map 72a), the particle size of the liquid water ejected from the nozzles 82 and 182 can be set to an optimum size according to the required load amount. The suppression of occlusion is realized more effectively.

  Furthermore, according to the fuel cell systems 100 and 500 of each of the above embodiments, the supply voltage to the water supply pump 83 and the air supply pump 85 is kept low during low load operation where the liquid water particle size may be relatively large. be able to. Therefore, overall power consumption in the fuel cell system can be suppressed.

  As described above, the present invention has been described based on the embodiments, but the present invention is not limited to the above-described embodiments, and various improvements and modifications can be easily made without departing from the spirit of the present invention. It can be guessed.

  For example, in each of the above embodiments, the required load amount-particle size map 72a (FIG. 6A) in which the relationship between the required load amount and the optimum particle size decreases linearly is exemplified. As long as the particle size during load operation is smaller than the particle size during low load operation, the relationship between the two may not be a primary proportional relationship.

  For example, a map that draws a curve that decreases the optimal particle size as the required load increases, a map that decreases the optimal particle size in stages as the required load increases, or a predetermined required load When the required load amount is larger than the threshold value with the amount as a threshold value, the optimum particle size decreases as the required load amount increases. When the required load amount is smaller than the threshold value, a certain particle size is set to the optimum particle size. The map may be as follows.

  Alternatively, it is determined only whether the operation is a high load operation or a low load operation. If the operation is a low load operation, a predetermined particle size (one size) is set as the optimum particle size. You may comprise so that particle size (1 size) smaller than the case may be made into an optimal particle size. When taking such a configuration, a predetermined required load amount is set as a threshold, and when the required load amount is smaller than the threshold, the first particle size is set as an optimal particle size, and when the required load amount is smaller than the threshold, A map can be used in which the second particle size smaller than the first particle size is the optimum particle size.

  In each of the above embodiments, the required load amount-particle size map 72a is configured to be used regardless of the required load amount. However, the map 72a is used only when the required load amount is larger than a predetermined amount. It may be configured to be used. In addition, what is necessary is just to set it as the particle size decided beforehand at the time of the low load operation which does not use this map 72a.

  In each of the above embodiments, each map 72a to 72d is used to obtain a desired value (for example, an optimum particle size), but the parameters represented by the horizontal axis in each map 72a to 72d You may comprise so that a desired value may be obtained based on the function linked | related with the parameter represented by a vertical axis | shaft.

1 is a system diagram showing a first embodiment of a fuel cell system of the present invention. (A) is a top view schematically showing the fuel cell stack, and (b) is a top view schematically showing cell modules constituting the fuel cell stack. (A) is the front view which looked at the cell module from the air electrode side, (b) is the front view which looked at the cell module from the fuel electrode side. (A) is IVa-IVa arrow principal part sectional drawing of Fig.3 (a), (b) is arrow principal part sectional drawing of Fig.3 (a). (A) is the front view which looked at the air electrode side collector from the separator main body side, (b) is the side view seen from the Vb direction in (a). (A) is a schematic diagram which shows the content of required load amount-particle size map, (b) is a schematic diagram which shows the content of feed water pump water pressure-particle size map. It is a flowchart which shows the operation control process performed in a control apparatus. 6 is a graph schematically showing a relationship between a required load amount and a substantial supply amount of air supplied to an air electrode. It is a systematic diagram which shows the fuel cell system of 2nd Embodiment. (A) is a schematic diagram which shows the content of feed water pump water pressure-particle size map, (b) is a schematic diagram which shows the content of feed air pump pressure-particle size map. It is a flowchart which shows the operation control process in 2nd Embodiment.

Explanation of symbols

10 Unit cell (fuel cell)
11 Solid polymer electrolyte membrane 12 Air electrode (oxygen electrode)
13 Fuel electrode 40 Fuel cell stack 72a Required load-particle size map (size storage means)
82,182 Nozzle 100,500 Fuel cell system

Claims (6)

A fuel cell comprising a solid polymer electrolyte membrane and a fuel electrode and an oxygen electrode sandwiching the solid polymer electrolyte membrane from both sides;
Fuel gas supply means for supplying fuel gas to the fuel electrode;
An oxidant gas supply means for supplying an oxidant gas to the oxygen electrode, and a water supply means for supplying the liquid water to the oxygen electrode by injection from the nozzle, comprising a nozzle for injecting liquid water in the form of a mist When,
A required load amount acquisition means for acquiring a required load amount for the fuel cell;
A fuel cell system comprising: a water particle size changing unit that adjusts the particle size of the liquid water ejected from the nozzle according to the required load amount acquired by the required load amount acquiring unit.   The water particle size changing means is a liquid water ejected from the nozzle when the required load quantity acquired by the required load quantity acquiring means is a second required load quantity that is larger than the first required load quantity. The fuel cell system according to claim 1, wherein the particle size of the fuel cell is smaller than the particle size with respect to the first required load amount. Size storage means for storing a relationship between a required load amount for the fuel cell and a particle size of liquid water ejected from the nozzle;
Size determining means for determining the particle size of liquid water ejected from the nozzle based on the required load amount acquired by the required load amount acquiring means and the relationship stored in the size storage means;
3. The fuel cell system according to claim 1, wherein the water particle size changing unit sets the particle size of the liquid water ejected from the nozzle to a size determined by the size determining unit. The nozzle is a one-fluid nozzle that ejects liquid water alone, and the particle size of the ejected liquid water can be changed according to the supply pressure of the liquid water supplied to the nozzle,
The water supply means further includes a water supply pump that pumps the liquid water to the nozzle,
The fuel according to any one of claims 1 to 3, wherein the water particle size changing means reduces the particle size of liquid water ejected from the nozzle by increasing a supply voltage to the water supply pump. Battery system. The nozzle is a two-fluid nozzle that injects gas into liquid water and injects, and the particle size of the liquid water to be injected is the supply pressure of the liquid water supplied to the nozzle and the gas supplied to the nozzle. It can be changed according to the supply pressure,
The water supply means further includes a feed water pump that pumps the liquid water to the nozzle, and a feed pump that pumps a gas to the nozzle,
The said water particle size change means reduces the particle size of the liquid water injected from the said nozzle by raising the supply voltage to the said water supply pump and the said air supply pump, Any one of Claim 1 to 3 characterized by the above-mentioned. A fuel cell system according to claim 1. A fuel cell comprising a solid polymer electrolyte membrane and a fuel electrode and an oxygen electrode sandwiching the solid polymer electrolyte membrane from both sides; fuel gas supply means for supplying fuel gas to the fuel electrode; and the oxygen An oxidant gas supply means for supplying an oxidant gas to the electrode, and a water supply means for supplying the liquid water to the oxygen electrode by injection from the nozzle, comprising a nozzle for injecting liquid water in the form of a mist, A fuel cell system operating method comprising:
A required load amount acquisition step for acquiring a required load amount for the fuel cell;
A water particle size changing step for adjusting the particle size of the liquid water ejected from the nozzle according to the required load amount acquired by the required load amount acquisition means. how to drive.

Images