JP2009076404A - Fuel battery cell and fuel battery stack - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel battery cell and a fuel battery stack capable of suitably restraining a moisture shortage in an anode electrode in a simple structure and displaying excellent power generation performance. <P>SOLUTION: In the fuel battery cell, a conductive fuel gas circulation section is brought into contact with the opposite side of a solid polymer electrolyte membrane in a first catalyst layer, numerous holes formed on a fuel gas circulating passage section become a circulating passage of a fuel gas, and the fuel gas is supplied to the first catalyst layer by circulating these holes. Here, the fuel gas circulation section is set up to has a hydrophilic property, liquid water supplied together with the fuel gas on the basis of this hydrophilic property can be effectively supplied to the first catalyst layer. Thus, moisture is effectively supplied to the first catalyst layer and a solid polymer electrolyte at an anode electrode side, in which moisture is apt to dry up, and deterioration of the power generation performance caused by moisture shortage at the anode electrode side can be effectively restrained. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a polymer electrolyte fuel cell and a fuel cell stack, and more particularly to a fuel cell and a fuel cell stack that can suitably suppress moisture shortage in an anode electrode and exhibit excellent power generation performance with a simple configuration. It is about.

  A unit cell of a solid polymer fuel cell (hereinafter simply referred to as “fuel cell”) has a solid polymer electrolyte membrane sandwiched between an anode electrode (fuel electrode) and a cathode electrode (oxidant electrode) A fuel gas (for example, hydrogen) supplied to the anode electrode and an oxidant gas (for example, air) supplied to the cathode electrode are electrochemically reacted to generate power.

Specifically, in the fuel cell, hydrogen is converted into protons (H ⁺ ) at the anode electrode (formula (1)), and the generated protons move to the cathode electrode through the solid polymer electrolyte membrane. It reacts with oxygen at the electrode to produce water (formula (2)). An electromotive force is obtained as a result of the reaction occurring at these anode and cathode electrodes.

Anode electrode: H ₂ → 2H ⁺ + 2e ⁻ (1)
Cathode electrode: (1/2) O ₂ + 2H ⁺ + 2e ⁻ → H ₂ O (2)

  In the fuel cell, water is generated at the cathode electrode, and when protons generated by the reaction at the anode electrode move to the cathode electrode, the water moves in a hydrated state. On the anode electrode side, there is a tendency that a water concentration gradient is generated in which the amount of water is small.

  Due to the concentration gradient of water, a part of water is back-diffused from the cathode electrode to the anode electrode. On the other hand, the amount of water movement accompanying proton movement from the anode electrode to the cathode electrode increases in proportion to the amount of proton movement (that is, increase in current density). Therefore, as the current density during operation increases, the amount of moisture on the anode electrode side decreases. As a result, even when humidified hydrogen of 100% RH is supplied to the anode electrode during operation at a high current density, the anode electrode Due to the lack of water on the side, there was a problem that the resistance of the solid polymer electrolyte membrane increased and a dry-up phenomenon that made it difficult to continue power generation occurred.

  As one of the techniques for solving such a problem, for example, in Patent Document 1, an anode (anode electrode) that is in close contact with an anode side catalytic reaction layer (catalyst layer) adjacent to an electrolyte membrane (solid polymer electrolyte membrane) is used as a separator. There has been proposed a cell of a fuel cell having a structure having a cross-linked polyacrylate impregnation on the side. Specifically, in the anode of the cell described in Patent Document 1, after forming porous carbon into a shape having a gas flow path on the separator side, the molded porous carbon is formed on the separator side (side on which the flow path is formed). Is immersed in a crosslinked polyacrylate solution so as to have an impregnated product of the crosslinked polyacrylate on the separator side.

  In the cell described in Patent Document 1, since the anode has a cross-linked polyacrylate impregnation on the separator side, the periphery of the cell is wet by the water absorption of the cross-linked polyacrylate impregnation. It is possible to make up for some excess or deficiency of water on the anode side by the impregnated product of the crosslinked polyacrylate.

In addition, it has been studied to supply moisture to the anode electrode using not only water vapor but also liquid water. Patent Document 1 also discloses an anode having a cross-linked polyacrylate impregnation on the separator side. A moisture supply device that directly supplies moisture is described. Furthermore, as a method of solving the moisture shortage on the anode electrode side, the solid polymer electrolyte membrane is made thin or the ion exchange capacity is increased. There is also a technique for promoting the reverse diffusion of moisture from the cathode electrode to the anode electrode.
Japanese Patent Laid-Open No. 7-326361 (for example, paragraphs [0048] to [0053] and FIG. 4)

  However, even in the cell described in Patent Document 1, there is still a problem that the shortage of moisture on the anode electrode side at the time of operation at a high current density is solved and insufficient power generation performance is exhibited. was there.

  In general, a fuel cell includes a layer that requires water repellency, such as a gas diffusion layer or a microporous layer (MPL), rather than a catalyst layer and a solid polymer electrolyte layer. Since it is arranged outside the thickness direction of the cell, even if liquid water is supplied to the anode electrode, the gas diffusion layer or pore layer having water repellency becomes an obstacle, and the catalyst layer or solid There is a problem that it is difficult to supply water to the molecular electrolyte membrane.

  Furthermore, when liquid water is supplied to the anode electrode using a moisture supply device as described in Patent Document 1, electrical energy for driving a pump or the like is required, and the entire power generation system is increased with the complexity of the device. There has been a problem that it causes problems such as an increase in size and an increase in manufacturing cost.

  In addition, when trying to eliminate the shortage of moisture on the anode electrode side by reducing the thickness of the solid polymer electrolyte membrane or increasing the ion exchange capacity, it is also possible to operate the anode during operation at a high current density. In addition to the insufficient moisture on the electrode side, there are problems such as a decrease in mechanical strength.

  The present invention has been made in order to solve the above-described problems, and provides a fuel cell and a fuel cell stack capable of suitably suppressing moisture shortage in the anode electrode with a simple configuration and exhibiting excellent power generation performance. It is intended to provide.

  In order to achieve this object, a fuel cell according to claim 1 includes a solid polymer electrolyte membrane, and a first catalyst layer that abuts on one surface of the solid polymer electrolyte membrane and functions as an anode electrode. A second catalyst layer that contacts the other surface of the solid polymer electrolyte membrane and functions as a cathode electrode, and is supplied to the first catalyst layer and to the second catalyst layer Power generation is performed using an electrochemical reaction that generates water from the oxidant gas, and is brought into contact with the side opposite to the solid polymer electrolyte membrane in the first catalyst layer, A plurality of holes serving as flow paths for the fuel gas supplied to the catalyst layer, and a hydrophilic fuel gas circulation section for supplying liquid water supplied together with the fuel gas to the first catalyst layer. Yes.

  The fuel cell according to claim 2 is the fuel cell according to claim 1, wherein a hydrophilic region continuous from the inside of the gas flow part to the first catalyst layer is formed in the flow path of the fuel gas. Yes.

  The fuel cell according to claim 3 is the fuel cell according to claim 1 or 2, further comprising water supply means for supplying liquid water together with the fuel gas to the fuel gas circulation part, A water reservoir provided below the anode electrode for storing water discharged from the anode electrode, and disposed facing the fuel gas flow supplied to the fuel gas circulation unit, and stored in the water reservoir A small hole for injecting water.

  The fuel cell according to claim 4 is the fuel cell according to any one of claims 1 to 3, wherein the fuel gas circulation portion is in contact with the first catalyst layer, Including a pore layer having a large number of pores communicating with each other, and the pore layer is made of a material containing at least conductive particles and a binder, and a part of the material is hydrophilic. And the remainder has water repellency.

  The fuel cell according to claim 5 is the fuel cell according to claim 4, wherein the fuel gas flow part is composed of the pore layer and a conductive porous body in contact with the pore layer, and the conductivity The surface of the porous body is hydrophilic.

  6. The fuel cell according to claim 5, wherein the surface of the conductive porous body is covered with a solid polymer electrolyte. Battery cell.

  The fuel cell according to claim 7 is the fuel cell according to any one of claims 1 to 6, wherein at least the inner peripheral surface of the small hole has water repellency.

  A fuel cell stack according to an eighth aspect includes a plurality of fuel battery cells according to any one of the first to seventh aspects, and is configured by electrically connecting the plurality of cells in series.

  According to the fuel cell of the first aspect, the fuel gas flow section having conductivity is in contact with the first catalyst layer on the opposite side of the solid polymer electrolyte membrane, and the fuel gas flow path section. A large number of holes formed in the gas flow path of the fuel gas, and the fuel gas flows through these holes and is supplied to the first catalyst layer.

  In this way, while supplying the fuel gas to the first catalyst layer, the oxidant gas is supplied to the second catalyst layer in contact with the surface of the solid polymer electrolyte membrane opposite to the first catalyst layer. As a result, the first catalyst layer functions as an anode electrode, the second catalyst layer functions as a cathode electrode, and an electrochemical reaction that generates water from the fuel gas and the oxidant gas occurs. Can be obtained.

  Here, the fuel gas circulation part is configured to have hydrophilicity, and the liquid water supplied together with the fuel gas can be efficiently supplied to the first catalyst layer due to the hydrophilicity. Therefore, there is an effect that moisture can be efficiently supplied to the first catalyst layer and the solid polymer electrolyte on the anode electrode side that are easily dried, and deterioration of power generation performance due to insufficient moisture on the anode electrode side can be effectively suppressed.

  According to the fuel cell of claim 2, in addition to the effect of the fuel cell of claim 1, the following effect is obtained. Since the hydrophilic region that is continuous from the inside of the gas circulation part to the first catalyst layer is formed in the flow path of the fuel gas, liquid water that is supplied together with the fuel gas and passes through the flow path of the fuel gas, This continuous hydrophilic region can be guided to the first catalyst layer. Therefore, there is an effect that moisture can be supplied more efficiently to the anode electrode side.

  The fuel cell according to claim 3 has the following effect in addition to the effect of the fuel cell according to claim 1 or 2. The liquid water is supplied to the fuel gas circulation part together with the fuel gas by a water supply means having a water reservoir and a small hole.

  Here, the water reservoir in the water supply means is provided below the anode electrode, and water discharged from the anode electrode can be stored in the water reservoir. Further, the small hole in the water supply means is arranged facing the fuel gas flow supplied to the fuel gas circulation part, and using the fuel gas flow, the liquid water stored in the water reservoir is It can be made to eject toward a fuel gas distribution part from a small hole.

  Therefore, according to the fuel cell of the third aspect, the flow of the fuel gas necessary for power generation is utilized, and the excess water present on the anode electrode side as a result of the electrochemical reaction is reused for humidification on the anode electrode side. Then, it can be supplied to the first catalyst layer and the solid polymer electrolyte membrane.

  Therefore, since water can be supplied to the anode electrode side without providing a separate water supply device that requires power, the power generation performance can be improved without increasing the size of the entire power generation system or increasing the manufacturing cost. Moreover, there is an effect that it is possible to avoid that the generated energy is consumed as a drive source.

  Also, when a fuel cell stack is configured by electrically connecting a plurality of fuel cells directly, the anode electrode side is suitably humidified in each fuel cell, which may cause a dry-up phenomenon in some fuel cells. There is an effect that it is possible to prevent the occurrence of power generation failure.

  In addition, when operating at a high current density, where the moisture on the anode electrode side tends to be insufficient, the flow rate (flow velocity) of the fuel gas also increases. As a result, the amount of water ejected from the small holes also increases, and the anode electrode There is an effect that more water can be supplied to the side. In addition, there is an effect that moisture on the anode electrode side (first catalyst layer and solid polymer electrolyte) can be controlled without requiring a feedback control mechanism such as impedance measurement.

  According to the fuel cell of claim 4, in addition to the effect of the fuel cell according to any of claims 1 to 3, the following effect is obtained. The fuel gas circulation part includes a pore layer having a large number of pores that are in contact with the first catalyst layer and communicate with each other. Here, since this pore layer is comprised from the material containing electroconductive particle and a binder, it has electroconductivity resulting from electroconductive particle.

  In addition, since part of the material including the conductive particles and the binder has hydrophilicity and the rest has water repellency, the hydrophilic material (for example, hydrophilic conductive particles and / or hydrophilicity) Forming a hydrophilic region caused by a water-repellent material and a water-repellent region caused by a water-repellent material (for example, water-repellent conductive particles and / or water-repellent binder) inside the pore layer. Can do.

  Examples of the “hydrophilic conductive particles” include, for example, conductive particles whose surfaces are rendered hydrophilic by various treatments (for example, conductive particles whose surfaces are coated with a hydrophilic material, hydrophilic treatments) , Etc.) and conductive particles whose surface is hydrophilic in advance because of being formed from a hydrophilic material.

  Therefore, water supplied together with the fuel gas (water supplied from the water reservoir through the small holes) can be easily supplied to the first catalyst layer and the solid polymer electrolyte membrane via the hydrophilic region. Therefore, there is an effect that the power generation performance can be improved.

  Further, water in the pore layer preferentially passes through the hydrophilic region as compared with the water-repellent region, so that it is easy to separate the water channel and the fuel gas channel, and the water fuel gas channel There is an effect that blockage can be prevented.

  According to the fuel cell of claim 5, in addition to the effect of the fuel cell of claim 4, the following effect is obtained. In addition to the pore layer, the fuel gas circulation section includes a conductive porous body that is in contact with the pore layer and has hydrophilicity on the surface thereof. Therefore, the liquid water supplied together with the fuel gas (for example, through a small pore) Liquid water supplied from the water reservoir) can be suitably moved from the conductive porous body to the pore layer, and as a result, water is suitably supplied to the catalyst layer and the solid polymer electrolyte. It becomes. Therefore, there is an effect that power generation performance can be improved.

  In addition, in claim 5, as the “conductive porous body having a hydrophilic surface”, for example, a conductive porous body whose surface is made hydrophilic by being formed of a hydrophilic material, Examples thereof include a conductive porous body whose surface is coated with a hydrophilic material (for example, a solid polymer electrolyte), and a conductive porous body whose surface is subjected to a hydrophilic treatment (such as an oxidation treatment or an alkali treatment).

  According to the fuel cell of claim 6, in addition to the effect of the fuel cell of claim 5, the following effect is obtained. Since the surface of the conductive porous body is coated with the solid polymer electrolyte, further hydrophilicity is imparted to the surface of the conductive porous body, and liquid water (for example, small pores) supplied together with the fuel gas is provided. The liquid water supplied from the water reservoir through the first catalyst layer can be more suitably moved to the first catalyst layer, and as a result, the power generation performance can be preferably improved.

  According to the fuel cell of claim 7, in the fuel cell according to any one of claims 1 to 6, at least the inner peripheral surface of the small hole has water repellency, so when the operation is stopped, That is, there is an effect that it is possible to prevent the liquid water stored in the water reservoir from flowing out when the flow rate (flow velocity) of the fuel gas becomes zero.

  According to the fuel cell stack of claim 8, since the fuel cells according to any one of claims 1 to 7 are configured to be electrically connected in series, the fuel cell stack according to any one of claims 1 to 7. The effect similar to the effect which the fuel cell of this invention produces | generates is show | played.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a perspective view schematically showing a fuel cell stack 50 having fuel cells 10 according to the first embodiment of the present invention. As shown in FIG. 1, the fuel cell stack 50 is a stacked body in which a plurality of later-described fuel cells 10 are stacked in the direction of arrows XX.

  In the fuel cell stack 50, adjacent fuel cells 10 include a conductive cathode side separator 11 (see FIG. 2) in one fuel cell 10 and a conductive anode side separator 12 (see FIG. 2). Electrically connected in series by contact with (see FIG. 2).

  In the fuel cell stack 50 of the present embodiment, the oxidant gas passage 12c (see FIG. 2) of the anode separator 12 (see FIG. 2) is disposed on the exposed surface of the fuel cell 10 located on the most front side in FIG. An oxidant gas supply port 50a communicating with the oxidant gas is opened, and the oxidant gas supplied to the cathode electrode 13 (see FIG. 4B) of each fuel cell 10 is supplied from the oxidant gas supply port 50a to the fuel. It is supplied into the battery stack 50.

  Further, the exposed surface of the fuel cell 10 located on the most front side in the fuel cell stack 50 shown in FIG. 1 communicates with the fuel gas flow path 12a (see FIG. 2) of the anode separator 12 (see FIG. 2). The fuel gas supply port 50b is opened, and the fuel gas supplied to the anode electrode 14 (see FIG. 4B) of each fuel cell 10 is supplied into the fuel cell stack 50 from the fuel gas supply port 50b. Is done.

  On the other hand, the exposed surface of the fuel cell 10 located on the innermost side in the fuel cell stack 50 shown in FIG. 1 communicates with the fuel gas passage 11b (see FIG. 2) of the cathode separator 11 (see FIG. 2). A fuel gas discharge port 50c (in FIG. 1, since it is on the back surface side of the fuel cell stack 50, is opened by a hidden line on the front side) is opened. The fuel gas supplied from the fuel gas supply port 50b to the inside of the fuel cell stack 50 is finally discharged from the fuel gas discharge port 50c.

  Therefore, each fuel cell 10 can be generated by supplying the oxidant gas and the fuel gas from the oxidant gas supply port 50a and the fuel gas supply port 50b to the inside of the fuel cell stack 50, respectively. As a result, a direct current can be extracted from the fuel cell stack 50. The fuel cell stack 50 is provided with current collecting terminals 50d and 50e at the top, and the current generated as a result of the power generation of each fuel cell 10 can be taken out from these current collecting terminals 50d and 50e as a direct current. it can.

  Next, with reference to FIGS. 2 to 5, the fuel cell 10 of the present embodiment that constitutes the fuel cell stack 50 will be specifically described. FIG. 2 is an exploded perspective view of the fuel battery cell 10. In the description of FIG. 2, the arrow U side is described as “up”, the arrow D side as “down”, the arrow R side as “right”, and the arrow L side as “left”.

  As shown in FIG. 2, the fuel cell 10 includes an anode separator 12, an inner manifold 21, a support plate 18 attached to the inner manifold 21, and an electrode assembly with a porous body flow path (hereinafter “porous”). 30) (hereinafter referred to as “MEA with body flow path”) and the cathode separator 11 are laminated bodies in this order.

  Both the anode side separator 12 and the cathode side separator 11 are configured as conductive plates. Here, an oxidant gas flow path 11a through which an oxidant gas flows and supplies the oxidant gas to the cathode electrode 13 (see FIG. 4B) is formed in a substantially rectangular cross section above the cathode separator 11.

  In addition, a fuel gas passage 11b for injecting fuel gas to be supplied to the anode electrode 14 (see FIG. 4B) is perforated on the lower right side of the cathode side separator 11, and the upper left side of the cathode side separator 11 is perforated. The fuel gas flow path 11c which becomes the discharge path of the fuel gas discharged from the adjacent fuel cell 10 is perforated.

  On the other hand, an oxidant gas flow path 12c for supplying an oxidant gas to the adjacent fuel cell 10 is formed on the upper side of the anode separator 12 so as to penetrate in a substantially rectangular section smaller than the oxidant gas flow path 11a.

  A fuel gas flow path 12b serving as a discharge path for the fuel gas discharged from the anode electrode 14 (see FIG. 4B) is perforated on the upper left side of the anode side separator 12, and the anode side separator 12 On the lower right side, a fuel gas passage 12a for supplying fuel gas to the adjacent fuel cells 10 is perforated.

  The inner manifold 21 is a resin member in which a fuel gas flow path that circulates inside the fuel cell 10 is formed, and is preferably made of a water-repellent resin such as polyethylene or polypropylene. Here, the configuration of the inner manifold 21 will be described with reference to FIG. 3 together with FIG. 2. 3A is a cross-sectional view of the inner manifold 21 shown in FIG. 2 as viewed from the direction of arrow IIIa, and FIG. 3B is a cross-sectional view of the inner manifold 21 shown in FIG. It is a perspective view of the back side.

  In FIG. 3A, one fuel gas channel 21b in the inner manifold 21 is illustrated by a virtual line, and the other fuel gas channel 21c is illustrated by a hidden line. In addition, the arrow shown in FIG. 3 shows the direction corresponding to FIG. That is, the arrow U side indicates “up”, the arrow D side indicates “down”, the arrow R side indicates “right”, and the arrow L side indicates “left”.

  The inner manifold 21 has a concave portion 21k and a window portion 21g, and is configured so that the MEA 30 with a porous channel can be accommodated in the concave portion 21k and the window portion 21g. Specifically, as shown in FIGS. 3 (a) and 3 (b), the inner manifold 21 has an oxidant gas passage 21a and fuel gas passages 21b and 21c on one side thereof inward of the surface direction. A concave portion 21k having a shape corresponding to the cathode electrode 13 and the solid polymer electrolyte 15 in the MEA 30 with a porous body flow passage is provided in the thickness direction. As shown in FIGS. 3A and 3B, the recess 21k is formed as a recess in which the lower end surface of the inner manifold 21 (the end surface on the arrow D side in FIG. 3B) is opened. Has been. The inner manifold 21 is formed with a window portion 21g having a shape corresponding to the anode electrode 14 in the MEA 30 with a porous channel in the thickness direction from the bottom surface of the recess 21k.

  As shown in FIGS. 2, 3 (a) and 3 (b), the inner manifold 21 includes an oxidant gas flow path 11 a of the cathode side separator 11 and an oxidant gas flow path 12 c of the anode side separator 12. An oxidant gas flow path 21a communicating with these flow paths 11a and 12c is formed at a position corresponding to. The oxidant gas path 21a is smaller than the oxidant gas flow path 11a and has a rectangular section substantially the same as the oxidant gas flow path 12c.

  Further, as shown in FIGS. 2 and 3B, the inner manifold 21 is provided with these at positions corresponding to the fuel gas flow path 11b of the cathode side separator 11 and the fuel gas flow path 12a of the anode side separator 12. A fuel gas channel 21b communicating with the channels 11b and 12a is perforated.

  Further, as shown in FIG. 2 and FIG. 3 (b), the inner manifold 21 has a position corresponding to the fuel gas flow path 11 c of the cathode side separator 11 and the fuel gas flow path 12 b of the anode side separator 12. A fuel gas passage 21c communicating with the passages 11c and 12b is perforated.

  Further, as shown in FIGS. 2 and 3 (a), on the surface of the inner manifold 21 opposite to the recess 21k, there is a groove portion 21d communicating with the fuel gas passage 21b, and the groove portion 21d to the bottom of the window portion 21g. A groove portion 21e extending to the opening end surface on the side is formed. Although details will be described later, in the fuel cell 10, the fuel gas flowing in from the fuel gas flow path 21 b flows through the groove portions 21 d and 21 e and is supplied to the anode electrode 14.

  On the other hand, as shown in FIGS. 2 and 3 (a), the surface of the inner manifold 21 opposite to the recess 21k communicates with the fuel gas passage 21c and overlaps with the upper opening end surface of the window portion 21g. A groove portion 21h extending while being formed is formed. Although details will be described later, in the fuel cell 10, the fuel gas discharged from the anode electrode 14 flows into the groove 21h from the upper end face side of the window 21g, and passes through the groove 21h and the fuel gas flow paths 21c and 11c. Finally, it is discharged from the fuel gas outlet 50c.

  Further, as shown in FIGS. 3 (a) and 3 (b), the inner manifold 21 has a bottom surface of the recess 21k on the lower side from the window 21g (arrow D side in FIG. 3 (b)). A concave portion 21i in which the opening end face side of the window portion 21g is opened and a concave portion 21m shallower than the concave portion 21i are respectively provided in the thickness direction. The recess 21m is recessed in a shape corresponding to the support plate 18. In the configuration of the fuel cell 10, the support plate 18 is mounted in the recess 21 m, and the water reservoir 40 having an opening on the opening end surface side of the window portion 21 i is formed from the recess 21 i and the support plate 18.

  As shown in FIGS. 2, 3A and 3B, a groove 21e of the inner manifold 21 is provided with a pinhole 21f communicating with a position below the recess 21i. In the pinhole 21f, when the fuel gas flows through the groove 21e, the internal pressure is reduced by the flow, so that the liquid water W (see FIGS. 4 and 5) is stored (stored) in the water reservoir 40. In this case, the liquid water W can be sucked up from the pinhole 21f and ejected toward the anode electrode 14 by the flow of the fuel gas.

  As described above, since the inner manifold 21 is made of water-repellent resin, the inner peripheral surface of the pinhole 21f is also water-repellent. Therefore, even when the flow rate of the fuel gas flowing through the groove 21e is reduced (particularly when the flow rate becomes zero), the outflow of the liquid water stored in the water reservoir 40 is prevented by the capillary exclusion pressure. Is done.

  Note that the diameter of the pinhole 21f is equal to the liquid water W stored in the water reservoir 40 even when the flow rate of the fuel gas flowing through the groove 21e is reduced (particularly when the flow rate is zero). Has a diameter that does not flow out of the pinhole 21f.

  Here, a pinhole in which the liquid water W does not flow out even when the flow rate of the fuel gas flowing through the groove 21e is reduced using the following formula (I) showing the relationship between the capillary pressure h and the capillary radius r. Consider a diameter of 21f.

h = 2T cos θ / (ρgr) (I)
h: capillary pressure [mAq], T: surface tension of liquid [N / m], θ: contact angle [degree],
ρ: density of liquid [kg / m ³ ], g: acceleration of gravity [m / s ² ],
r: inner diameter (radius) of the capillary [m]

  The water pressure (that is, the height from the center of the pinhole 21f to the water surface of the liquid water W) h received by the liquid water W stored in the water reservoir 40 is 0.01 to 0.05 [mAq]. The contact angle θ of the inner peripheral wall of the pinhole 21f is about 95 to 105 [degrees] exhibited by a water-repellent resin such as polyethylene or polypropylene, and the environmental temperature that affects the surface tension T and the density ρ. Is 10 to 80 [° C.], the diameter (2r) of the pinhole 21f for preventing the liquid water W from flowing out of the pinhole 21f needs to be about 0.04 to 0.8 [mm]. It is calculated that there is.

  As shown in FIG. 2, the MEA 30 with a porous flow path is disposed on one side of the solid polymer electrolyte membrane 15 and the solid polymer electrolyte membrane 15, and has substantially the same shape as the solid polymer electrolyte membrane 15. A cathode electrode 13 having a solid electrolyte electrolyte membrane 15 and an anode electrode 13 disposed on a surface of the solid polymer electrolyte membrane 15 opposite to the cathode electrode 13 and configured to be smaller than the solid polymer electrolyte membrane 15 and the cathode electrode 14. It is a laminated body.

  In the MEA 30 with a porous body flow path, the support plate 18 is attached to the recess 21m of the inner manifold 21, and then the anode electrode 14 of the MEA 30 with the porous body flow path is loosely inserted into the window portion 21g, thereby solid polymer electrolyte membrane 15 Is brought into contact with the bottom surface of the recess 21k, and the contact portion is bonded (sealed) to be accommodated in the inner manifold 21.

  The cathode separator 11 is disposed on the cathode electrode 13 side of the inner manifold 21 in which the MEA 30 with a porous channel is accommodated, and the anode separator 12 is disposed on the other side. The fuel battery cell 10 is configured by sandwiching 21.

  4A is a plan view of the fuel cell 10 as viewed from the direction of the arrow IVa in FIG. 2, that is, as viewed from the anode separator 12 side, and FIG. 4B is a plan view of FIG. It is sectional drawing of the fuel cell 10 in the IVb-IVb line | wire in FIG. FIG. 5 is an enlarged view of a portion E in FIG.

  In order to facilitate understanding, in FIG. 4A, a part of the structure (oxidant gas flow path 11a, grooves 21d, 21e, 21h, hidden on the back side (back side of the paper) of the anode-side separator 12; The window 21g and the pinhole 21f) are illustrated by hidden lines, and in FIG. 4B, the fuel gas flow path 11b of the cathode side separator 11 and the fuel gas flow path 12a of the anode side separator 12 are illustrated by phantom lines. The fuel gas flow path 11c of the cathode side separator 11 is illustrated by hidden lines.

  As described above, the MEA 30 with a porous flow path is a laminated structure including the solid polymer electrolyte membrane 15 and the solid polymer electrolyte cathode electrode 13 and the anode electrode 14 disposed on one side of the solid polymer electrolyte 15. Is the body. Here, examples of the solid polymer electrolyte membrane 15 include solid polymers applicable to solid polymer fuel cells such as Nafion (registered trademark: manufactured by DuPont) and Aciplex (registered trademark: manufactured by Asahi Kasei Co., Ltd.). An electrolyte membrane can be used.

  As shown in FIG. 4B, the cathode electrode 13 includes a plate-like porous body 13a, a pore layer (MPL) 13b disposed on one side of the porous body 13a, and a porous layer in the pore layer 13b. The catalyst layer 13c disposed on the surface opposite to the body 13a is integrally formed.

  The anode electrode 14 is configured in the same manner as the cathode electrode 13 described above except for the size (area). That is, as shown in FIG. 4B, the anode electrode 14 also has a plate-like porous body 14a, a pore layer (MPL) 14b disposed on one surface of the porous body 14a, and the pore layer. The catalyst layer 14c disposed on the opposite surface of the porous body 14a in 14b is integrally formed.

  As the catalyst layers 13c and 14c, for example, a catalyst layer including a catalyst-supporting carbon in which a catalyst such as platinum is supported on carbon particles and an electrolyte can be employed. As shown in FIG. 4B, the cathode electrode 13 is disposed with the catalyst layer 13c in contact with the solid polymer electrolyte membrane 15, while the anode electrode 14 has the catalyst layer 14c disposed on the solid polymer electrolyte. These catalyst layers 13c and 14c are disposed in contact with the membrane 15, and promote the electrochemical reaction between oxygen and hydrogen.

  The porous bodies 13a and 14a are conductive and have many holes communicating with each other (for example, holes having a minimum inner diameter of about 10 μm to 500 μm). Such porous bodies 13a and 14a can be composed of a net material formed in a three-dimensional network or a foam material in which open cells are formed. Here, for example, when a mesh material made of fibers is adopted as the porous body, conductive fibers are used because the mesh material needs to have conductivity. As the conductive fibers, for example, metal fibers having corrosion resistance and conductivity such as titanium, SUS, tantalum, and hastelloy, and fibers such as nickel and carbon can be used. The mesh material may be a woven fabric or a non-woven fabric.

  Thus, in this embodiment, since the porous bodies 13a and 14a having many vacancies communicating with each other are employed in the electrodes 13 and 14, such vacancies are formed by oxidizing gas (in this embodiment, Air) and fuel gas (hydrogen in this embodiment) function as part of the flow path. That is, the cathode electrode 13 of this embodiment has both a function as a cathode electrode and a function as a gas flow path (oxidant gas flow path). Similarly, the anode electrode 14 of the present embodiment has both a function as an anode electrode and a function as a gas flow path (fuel gas flow path).

  Moreover, since the porous bodies 13a and 14a have hydrophilicity as well as conductivity, water generated by the reaction can be diffused in the thickness direction of the porous bodies 13a and 14a. This is preferable. In the present embodiment, a mesh material (titanium fiber sintered plate) made of hydrophilic titanium fibers is employed as the porous bodies 13a and 14a.

  In particular, the porous body 14a of the anode electrode 14 has a hydrophilic surface so that water (water vapor, liquid water) supplied for the purpose of humidification is easily diffused in the thickness direction, and the catalyst layer 14c. In addition, it has an advantage that it can easily move to the solid polymer electrolyte membrane 15 side, that is, water supplied for the purpose of humidification can easily reach the catalyst layer 14c and the solid polymer electrolyte membrane 15 side.

  The porous body 14a of the anode electrode 14 is immersed in a solution of a solid polymer electrolyte (for example, Nafion (registered trademark: manufactured by DuPont)) and then dried to cover the hydrophilic solid polymer electrolyte membrane. be able to. In addition, it is possible to further impart hydrophilicity to the surface by coating the surface with a hydrophilic material such as a metal oxide or by applying a hydrophilic treatment such as a surface oxidation treatment to the surface. . By imparting further hydrophilicity to the surface of the porous body 14a of the anode electrode 14, the water supplied for the purpose of humidification can reach the catalyst layer 14c and the solid polymer electrolyte membrane 15 side more reliably. In addition, when coat | covering the surface of the porous body 14a with a hydrophilic material, it is preferable to coat | cover with a thin film so that the electroconductivity of the porous body 14a may be maintained.

In this embodiment, as the porous body 14a of the anode electrode 14, the surface is coated with a solid polymer electrolyte (Nafion (registered trademark: manufactured by DuPont)) at a coating amount of about 4 to 5 mg / cm ² , and further has hydrophilicity. An improved titanium fiber sintered plate was used.

  The pore layers 13b and 14b are conductive and have many holes communicating with each other. The pores in the pore layers 13b and 14b are smaller than the pores of the porous bodies 13a and 14a described above (for example, the minimum inner diameter is about 0.01 μm to several μm and the peak is less than about 2 μm). Hole). Moreover, the catalyst is not contained in the pore layers 13b and 14b. The pore layers 13b and 14b are formed with a thickness of 200 μm or less, for example.

  The pore layers 13b and 14b function as gas passages for supplying gas (oxidant gas, fuel gas) flowing through the porous bodies 13a and 14a to the catalyst layers 13c and 14c, and the catalyst layers 13c and 14c and the porous body. The function of facilitating electron transfer between 13a and 14a, and the water in the catalyst layers 13c and 14c are moved to the pore layers 13b and 14b, so that the excess water can be removed from the system while retaining the catalyst layer appropriately. It discharges, and bears the function of suppressing the electrochemical reaction in the catalyst layers 13c and 14c from being inhibited by water.

  The pore layers 13b and 14b include conductive particles such as carbon particles and a binder, and the binder is a water repellent material such as PTFE (Polytetrafluoroethylene), polyethylene, or polypropylene. By using, water repellency can be imparted to the pore layers 13b and 14b. Since the pore layers 13b and 14b have water repellency, water that has moved into the pore layers 13b and 14b can be easily discharged from the pore layers 13b and 14b, which is preferable because the power generation density is improved.

  In the present embodiment, as the pore layers 13b and 14b, for example, pore layers composed of conductive particles (for example, carbon particles such as carbon black) and PTFE as a binder are employed.

  However, the pore layer 14b of the anode electrode 14 was made of conductive particles imparted with hydrophilicity as carbon particles. Examples of conductive particles imparted with hydrophilicity include carbon black whose surface is coated with Nafion (registered trademark: manufactured by DuPont), which is a solid polymer electrolyte, and carbon black subjected to surface oxidation treatment. it can.

  Thus, since the pore layer 14b of the anode electrode 14 is configured to include conductive particles imparted with hydrophilicity and PTFE, the pore layer 14b includes a conductive property imparted with hydrophilicity. A hydrophilic region substantially continuous in the thickness direction caused by the conductive particles and a water repellent region caused by PTFE are formed.

  Therefore, the pore layer 14b of the anode electrode 14 easily moves water (water vapor, liquid water) supplied from the porous body 14a side for the purpose of humidification to the catalyst layer 14c and the solid polymer electrolyte membrane 15, thereby The layer 14c and the solid polymer electrolyte membrane 15 also have a function of suppressing the occurrence of moisture deficiency.

  In addition, the pore layer 14b has a water-repellent region formed due to PTFE which is water-repellent therein. Since water in the pore layer 14b preferentially passes through the hydrophilic region compared to the water-repellent region, the water channel and the fuel gas channel are easily separated, and the water-repellent region is blocked by water. As a result, blockage of the gas flow path is prevented.

  The pore layer 14b of the anode electrode 14 includes a hydrophilic binder such as polymethyl methacrylate (PMMA) or polycarbonate in addition to conductive particles imparted with hydrophilicity and a water-repellent binder (for example, PTFE). It may be configured to include. By using a hydrophilic binder, a hydrophilic region can be formed by the hydrophilic binder, and dispersion of conductive particles imparted with hydrophilicity is assisted.

  As shown in FIGS. 4A and 4B, the oxidant gas flows into the fuel cell 10 from the oxidant gas flow path 12 c of the anode side separator 12. Part of the oxidant gas flowing in from the oxidant gas flow path 12c is supplied to the adjacent fuel cell 10 via the oxidant gas flow path 21a and the oxidant gas flow path 11a, and the rest is It is supplied to the porous body 13 a of the cathode electrode 13.

  On the other hand, the oxidant gas supplied to the porous body 13a of the cathode electrode 13 flows through the pores of the porous body 13a in the direction of arrow A, and a part of the oxidant gas is used for the reaction in the catalyst layer 13c. The remaining oxidant gas that has not been used for is discharged from the lower end of the cathode electrode 13. Further, water generated at the cathode electrode 14 during the reaction is also discharged from the lower end of the cathode electrode 13.

  Further, as shown in FIGS. 4A and 4B, the fuel gas flows into the fuel cell 10 from the fuel gas flow path 12 a of the anode side separator 12. A part of the fuel gas flowing in from the fuel gas channel 12a is supplied to the adjacent fuel cell 10 via the gas channel 21b (see FIG. 2) and the fuel gas channel 11b.

  The remainder of the fuel gas flowing in from the fuel gas passage 12a passes through the fuel gas passage 21b and the groove portion 21d, flows through the groove portion 21e in the direction of the arrow B1, and is formed in the opening end surface below the window portion 21g. Is supplied to the porous body 14 a of the anode electrode 14.

  On the other hand, the fuel gas supplied to the porous body 14a of the anode electrode 14 flows through the pores of the porous body 14a in the direction of the arrow B2, and a part of the fuel gas is used for the reaction in the catalyst layer 14c. The remaining fuel gas that has not been used is discharged from the fuel gas passage 11c through the groove 21h and the fuel gas passage 21c (see FIG. 2).

  Excess liquid water present in the anode electrode 14 is discharged from the lower end of the anode electrode 14, received by the water reservoir 40 opened below the anode electrode 14, and liquid water W in the internal space of the water reservoir 40. Can be stored as

  As shown in FIG. 5, when the liquid water W is stored in the water reservoir 40 and the fuel gas flows through the groove 21e in the direction of the arrow B1, the liquid stored in the water reservoir 40 is caused by the flow. Water W is sucked out from the pinhole 21f and is jetted upward by the flow of fuel gas (arrow B1). Thus, according to the configuration of the fuel battery cell 10 of the present embodiment, the liquid water W stored in the water reservoir 40 is supplied to the anode electrode 14 using the flow of fuel gas used for power generation. It can be done.

Here, using the following Formula (II), consider the flow velocity U _H of the fuel gas required from the pinhole 21f to cause outflow of liquid water W. Incidentally, formula (II), the pressure pin hole 21f is subjected when the flow rate of the fuel gas passing through the groove 21e is _{U H} and Pa [N / ^{m 2],} the flow rate of the water reservoir 40 is zero Assuming that there is a model, Bernoulli's theorem is developed for a model in which the gas pressure in the water reservoir 40 (gas phase pressure in the water reservoir 40) is Pb [N / m ² ].

U _H = √ {2 (Pb−Pa) / ρ _H } (II)
U _H : Fuel gas flow velocity [m / s]
ρ _H : fuel gas density [kg / m ³ ]

Here, since (Pb-Pa) corresponds to the capillary pressure of N / m ² unit, the formula (II) can be handled as the following formula (III).

U _H = √ {2 (h ′) / ρ _H } (III)
h ′: Capillary pressure [N / m ² ]

When the capillary pressure is about 0.01 to 0.05 [mAq] and hydrogen gas is used as the fuel gas, the environmental temperature affecting the hydrogen density ρ _H is 10 to 80 [° C.]. It is calculated that about 40 to 120 [m / s] is required as the flow rate U _H of the fuel gas (hydrogen gas) necessary for flowing the liquid water W out of the pinhole 21f.

Note that the amount of hydrogen consumption V _H required to operate the fuel cell 10 at a current density of 1 [A / cm ² ] at an environmental temperature of 10 to 80 ° C. is 1.0112 according to Faraday's law. Since the required fuel gas flow rate U _H is 40 to 120 [m / s], the cross-sectional area of the flow path is about 0.1 to 0.4 mm ^2. It is calculated to be a degree.

  As described above, according to the fuel cell 10 of the present embodiment, the water reservoir 40 having the opening facing the lower end of the anode electrode 14 is formed below the anode electrode 14. Excess water that falls by gravity from the lower end of the water can be stored in the water reservoir 40.

  Since the water reservoir 40 is formed with a pinhole 21f communicating with the groove 21e serving as a flow path for the fuel gas, the fuel gas is allowed to flow through the groove 21e at a sufficient flow rate so that the interior of the water reservoir 40 can be obtained. The liquid water W stored in the gas is sucked out from the pinhole 21f and is ejected toward the anode electrode 14 by the flow of the fuel gas.

  Thus, according to the configuration of the fuel battery cell 10 of the present embodiment, the liquid water W stored in the water reservoir 40 is supplied to the anode electrode 14 using the flow of fuel gas used for power generation. be able to.

  Further, according to the fuel cell 10 of the present embodiment, the porous body 14a in the anode electrode 14 is composed of hydrophilic titanium fibers and the surface thereof is coated with a thin film made of a solid polymer electrolyte. Further hydrophilicity is imparted to the surface. Therefore, the porous body 14a can easily diffuse the liquid water ejected from the pinhole 21f in the thickness direction, and as a result, the liquid water can be reliably moved to the pore layer 14b. .

  Furthermore, according to the fuel cell 10 of the present embodiment, the pore layer 14b in the anode electrode 14 is configured to include conductive particles imparted with hydrophilicity and PTFE which is a water-repellent binder. In the pore layer 14b, a hydrophilic region due to the conductive particles imparted with hydrophilicity is formed, and the liquid water that has moved from the porous body 14a is allowed to pass through the hydrophilic region to form the catalyst layer 14c. And can be easily supplied to the solid polymer electrolyte 15.

  On the other hand, a water-repellent region formed due to the water-repellent binder is also formed in the pore layer 14b. Since water in the pore layer 14b preferentially passes through the hydrophilic region as compared with the water-repellent region, the water channel and the fuel gas channel are easily separated. Therefore, it is possible to prevent the water repellent region from being blocked by water and the gas flow path from being blocked, and to ensure the gas supply property to the catalyst layer 14c.

  As described above, according to the fuel cell 10 of the present embodiment, the porous body 14a and the pore layer 14b of the anode electrode 14 both have hydrophilicity imparted to the surface (at least a part of the surface). A hydrophilic region (hydrophilic path) substantially continuous to the catalyst layer 14c is formed in the thickness direction.

  Therefore, the liquid water ejected from the pinhole 21f toward the anode electrode 14 (particularly the porous body 14a) is efficiently supplied to the catalyst layer 14c and the solid polymer electrolyte 15 due to the presence of the hydrophilic region. Can do. Therefore, according to the fuel cell 10 of the present embodiment, the catalyst layer 14c and the electrolyte 15 that are likely to be deficient in moisture can be reliably wetted, and excellent power generation performance can be exhibited.

  Here, the humidification of the catalyst layer 14c and the solid polymer electrolyte 15 in the fuel cell 10 of the present embodiment utilizes the flow of the fuel gas necessary for power generation as described above, and as a result of the electrochemical reaction, the anode electrode 14 The excess water generated on the side is reused. That is, according to the fuel cell 10 of the present embodiment, the catalyst layer 14c and the solid polymer electrolyte 15 can be humidified without separately providing a water supply device that requires power, so that the entire power generation system can be increased in size and manufactured. It is possible to improve the power generation performance without incurring an increase in cost and the like, and it is also possible to avoid the generated energy from being consumed as a drive source.

  In particular, during operation at a high current density where the moisture on the anode electrode 14 side tends to be insufficient, the flow rate (velocity) of the fuel gas inevitably increases. As a result, the amount of water ejected from the pinhole 21f As a result, more water can be supplied to the anode electrode 14 side. Therefore, even during operation at a high current density, the catalyst layer 14c and the solid polymer electrolyte 15 can be reliably wetted, and deterioration in power generation performance can be suppressed. In addition, moisture in the solid polymer electrolyte membrane 15 can be controlled without requiring a feedback control mechanism such as impedance measurement.

  Note that, according to the fuel cell 10 of the present embodiment, the porous body in the anode electrode 14 is configured as a conductive porous body, and the conductive porous body is filled with water by pores communicating with each other. Since it is diffused in the thickness direction and the entire surface direction, the region for supplying moisture to the catalyst layer 14c and the solid polymer electrolyte membrane 15 is larger than that of a conventional fuel cell using a ribbed separator. Can be wide. Therefore, it is preferable in that water can be efficiently supplied to the catalyst layer 14c and the solid polymer electrolyte membrane 15, and as a result, the power generation performance can be improved more effectively.

  Further, according to the fuel battery cell 10 of the present embodiment, since the inner manifold 21 is made of water-repellent resin, the inner peripheral surface of the pinhole 21f can be made water-repellent. Since the inner peripheral surface of the pinhole 21f is configured to be water repellent, when the operation is stopped, that is, when the flow rate (flow velocity) of the fuel gas becomes zero, the pinhole 21f is stored in the water reservoir 50. The outflow of liquid water can be prevented by capillary exclusion pressure.

  In addition, according to the fuel cell stack 50 of the present embodiment, the fuel cell 10 of the present embodiment described above in which the anode electrode 14 side is suitably humidified is configured to be electrically connected directly. Occurrence of power generation failure due to a dry-up phenomenon in the battery cell 10 can be prevented.

  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 the above embodiment, the cathode electrode 13 is configured to include the porous body 13a, the pore layer 13b, and the catalyst layer 13c, but if the cathode electrode 13 includes a catalyst layer that contacts the solid polymer electrolyte 15, The configuration is not particularly limited. For example, a catalyst layer in contact with the solid polymer electrolyte 15 is used as a cathode electrode, and oxidation is performed from an oxidant gas channel formed between ribs to a catalyst layer (cathode electrode) using a conventional separator with ribs. The structure etc. which supply agent gas may be sufficient.

  In the above embodiment, the anode 14 has the configuration in which the porous body 14a and the pore layer 14b are used as a flow path for supplying the fuel gas to the catalyst layer 14c. However, the fuel gas is supplied to the catalyst layer 14c. The flow path is not limited to such a configuration. For example, only the porous body 14a may be used without using the pore layer 14b. Moreover, it may replace with the pore layer 14b and may be a layer like the gas diffusion layer generally used conventionally. However, it is essential to have a hydrophilic region (hydrophilic route) through which water can flow.

  In the above embodiment, the anode electrode 14 includes the porous body 14a, and the pores of the porous body 14a function as a fuel gas passage. Instead of the porous body 14a, a conductive sheet-like network A separator obtained by forming a member (for example, expanded metal or wire mesh) or a conductive plate having a large number of through holes into an uneven shape may be used as the fuel gas passage. In that case, it is preferable to impart hydrophilicity to the surface of these separators (for example, formation from a hydrophilic material, coating with a hydrophilic material, or imparting hydrophilicity by surface treatment). By using a separator obtained by forming a sheet-like net-like member having conductivity or a conductive plate with a large number of through holes formed into a concavo-convex shape, and imparting hydrophilicity to the surface of the separator, The humidification effect | action of the catalyst layer 14c and the solid polymer electrolyte 15 similar to the fuel cell 10 of a form can be obtained.

  Moreover, in the said embodiment, although the titanium fiber sintered board by which the surface was coated with the thin film by a solid polymer electrolyte was used as the porous body 14a of the anode electrode 14, hydrophilicity like a titanium fiber sintered board is used. If it is a porous body (conductive porous body) made of the material it has, it is possible to obtain the humidifying action of the catalyst layer 14c and the solid polymer electrolyte 15.

  Moreover, in the said embodiment, although the pore layer 14b of the anode electrode 14 was comprised from the electroconductive particle (carbon particle) to which hydrophilic property was provided, and PTFE, the electroconductivity to which hydrophilic property was provided. Not only particles but also untreated conductive particles may be included.

  Moreover, in the said embodiment, the pore layer 14b of the anode electrode 14 is comprised including the electroconductive particle (carbon particle) to which hydrophilic property was provided, and hydrophilic property is provided to the pore layer 14b (hydrophilic property). The region is formed), but untreated conductive particles are used instead of conductive particles imparted with hydrophilicity, and hydrophilic binders (for example, PMMA, polycarbonate, etc.) are used instead of water-repellent binders. ) May be used to form a hydrophilic region resulting from a hydrophilic binder.

  In the above embodiment, the inner manifold 21 is made of a resin having water repellency. However, only one member including the pinhole 21f portion is formed from the resin having water repellency, and the inner manifold 21 is made of metal or the like. It may be configured to be worn. Moreover, the structure which comprises only the water sump part 40 from another member, and may mount | wear may be sufficient. The inner manifold 21 including the water reservoir 40 and the pinhole 21f is manufactured by integral molding from a resin having water repellency, so that the water reservoir 40 and the pinhole can be easily obtained without increasing the number of parts and the manufacturing process. The fuel battery cell 10 having 21f can be manufactured.

  Moreover, in the said embodiment, although it was set as the structure which has only one pinhole 21f, the number of this pinhole is not limited to one, You may form multiple. For example, the inner manifold 21 shown in FIG. 2 has a plurality of similar pinholes in the left-right direction (in the direction of the arrow LR in FIG. 2) of the pinhole 21f formed substantially at the center. The groove part similar to the groove part 21f extended from the groove part 21d may be formed.

  The fuel cell and the fuel cell stack of the present invention exemplified as the above embodiments can be used as various power sources such as a moving power source for an electric vehicle, an outdoor stationary power source, a portable power source, and a portable electronic device power source. is there.

It is a perspective view showing typically a fuel cell stack which has a fuel cell in one embodiment of the present invention. It is a disassembled perspective view of a fuel cell. (A) is sectional drawing at the time of seeing the cross section in the ZZ line of the inner manifold shown in FIG. 2 from the arrow IIIa direction, (b) is a perspective view of the back surface side in the inner manifold 21 shown in FIG. It is. (A) is a top view of the fuel battery cell seen from the arrow IVa direction of FIG. 2, (b) is sectional drawing of the fuel battery cell in the IVb-IVb line | wire in (a). It is an enlarged view of the E section in FIG.4 (b).

Explanation of symbols

10 Fuel cell 13c Catalyst layer (second catalyst layer)
14a Porous body (part of gas flow part, conductive porous body)
14b Pore layer (part of gas flow part, pore layer)
14c Catalyst layer (first catalyst layer)
15 Solid polymer electrolyte membrane 21f Pinhole (small hole)
40 Water reservoir 50 Fuel cell stack

Claims (8)

A solid polymer electrolyte membrane, a first catalyst layer that abuts on one surface of the solid polymer electrolyte membrane and functions as an anode electrode, abuts on the other surface of the solid polymer electrolyte membrane, and serves as a cathode electrode A second catalyst layer that functions, and using an electrochemical reaction that generates water from a fuel gas supplied to the first catalyst layer and an oxidant gas supplied to the second catalyst layer A fuel cell for generating electricity,
The first catalyst layer is in contact with the opposite side of the solid polymer electrolyte membrane, and a plurality of holes serving as a flow path for the fuel gas supplied to the first catalyst layer are formed and supplied together with the fuel gas A fuel cell comprising a fuel gas circulation part having hydrophilicity to supply liquid water to the first catalyst layer.   2. The fuel cell according to claim 1, wherein a hydrophilic region that continues from the inside of the gas circulation part to the first catalyst layer is formed in the flow path of the fuel gas. Water supply means for supplying liquid water together with the fuel gas to the fuel gas circulation part;
The water supply means
A water reservoir portion provided below the anode electrode for storing water discharged from the anode electrode;
A small hole for injecting water stored in the water reservoir, disposed facing the fuel gas flow supplied to the fuel gas circulation unit;
The fuel cell according to claim 1, wherein The fuel gas flow part includes a pore layer having a large number of pores in contact with the first catalyst layer and in communication with the first catalyst layer,
The pore layer is made of a material containing at least conductive particles and a binder, and part of the material has hydrophilicity and the rest has water repellency. The fuel battery cell according to any one of 1 to 3. The fuel gas flow part is composed of the pore layer, and a conductive porous body in contact with the pore layer,
The fuel cell according to claim 4, wherein the surface of the conductive porous body is hydrophilic.   6. The fuel cell according to claim 5, wherein the surface of the conductive porous body is coated with a solid polymer electrolyte.   7. The fuel cell according to claim 1, wherein at least an inner peripheral surface of the small hole has water repellency. A plurality of the fuel cells according to any one of claims 1 to 7,
A fuel cell stack configured by electrically connecting the plurality of cells in series.

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