JP2008123707A - Fuel battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel battery which can prevent a gas shortage due to imbalance of a water distribution because of a separated positioning of a supply port and an outlet or a varied status of reaction gas concentration, or a pressure loss variation in a comb-tooth profile passage. <P>SOLUTION: The fuel battery l is composed of cells in which an ion-conductive electrolyte is pinched between a fuel electrode and an oxidant electrode and which are pinched by a fuel passage plate provided with a passage to supply fuel gas to the fuel electrode and an oxidant passage plate provided with a passage to supply an oxidant gas to the oxidant electrode, and at least either the fuel passage plate or the oxidant passage plate is provided with a supply passage and an exhaust passage arranged in an opposite face not contacting a corresponding electrode, a supply hole and an exhaust hole which penetrate the passage plate and are connected each with the supply passage and the exhaust passage and a plurality of combining passages which are arranged in parallel on an electrode surface contacting a corresponding electrode and combine the supply hole and the exhaust hole on the electrode surface. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a fuel cell that generates electricity using an electrochemical reaction.

  In a fuel cell, a pair of electrodes are opposed to each other via an electrolyte, fuel is supplied to one of the electrodes, an oxidant is supplied to the other electrode, and the oxidation of the fuel is electrochemically reacted in the cell to generate chemical energy. Is a device that directly converts electricity into electrical energy. There are several types of fuel cells depending on the electrolyte. Recently, a solid polymer fuel cell using a proton conductive solid polymer electrolyte membrane as an electrolyte has attracted attention as a fuel cell capable of obtaining high output. When hydrogen gas is supplied to the fuel electrode and oxygen gas is supplied to the oxidant electrode, hydrogen gas is reduced at the fuel electrode to generate protons, and at the oxidant electrode, protons that have passed through the electrolyte membrane are oxidized to produce water. The With this reaction, a potential difference of 1.23 V is generated between the fuel electrode and the oxidant electrode, and a current flows from the oxidant electrode to the fuel electrode.

  By the way, in the polymer electrolyte fuel cell, in order for protons to conduct through the electrolyte membrane, the solid polymer electrolyte membrane needs to be in a water-containing state, and humidification control is an essential technique. When the water content of the solid polymer electrolyte membrane decreases, the electrical resistance of the electrolyte membrane increases, leading to a decrease in output voltage and a decrease in output power. Further, when the water content decreases and the polymer electrolyte membrane becomes dry, the solid polymer electrolyte membrane does not function as an electrolyte membrane.

  Therefore, it is widely performed to positively humidify the solid polymer electrolyte membrane by humidifying the hydrogen gas or oxygen gas and supplying the fuel cell. However, when the amount of humidified water or reaction product water exceeds the amount of water retained in the electrolyte membrane, a phenomenon called flooding occurs in which they are condensed and water overflows into the gas flow path. When flooding occurs, water covers the power generation surface of the electrode to suppress the reaction, causing a phenomenon of blocking the gas flow by closing the supply gas flow path, making it difficult to stably continue power generation.

  As a technique for eliminating the flooding, in the gas flow path formed in the separator provided with water moving means for moving water between the gas supply side flow path and the gas discharge side flow path, the supply side gas flow Comb channel fuel that makes it easy to discharge condensed water by separating the channel so that the channel and the discharge side gas channel are not directly connected, and forcing the supply gas through the gas diffusion layer A battery has been proposed (see, for example, Patent Document 1).

Further, in the power generation state of the fuel cell, the oxygen partial pressure (concentration) is high on the supply port side in the fluid channel of the oxidant electrode, and the moisture is low. On the contrary, on the discharge side, the oxygen partial pressure is low, and an imbalance occurs in which there is a lot of moisture. Further, an imbalance occurs in which the hydrogen partial pressure is high on the fuel supply side and the hydrogen partial pressure is low on the discharge side. Water imbalance is particularly noticeable when the dew point of the reaction gas to be supplied is low, the ionic conductivity of the electrolyte membrane decreases near the dry supply port, and water accumulates in the electrode near the wet discharge port. There is a problem that the output of the battery is greatly reduced because the diffusion of gas to the surface of the electrode catalyst is inhibited.
If these imbalances can be eliminated, the cell performance is expected to improve. However, in the conventional fuel cell configuration, the fuel and oxidant supply ports and discharge ports are located at diagonally separated positions on the separator plate. It is difficult for the substance to move and eliminate the imbalance.

  In addition, there is a problem that the battery performance deteriorates because the electrode is oxidized in the process of supplying and stopping the gas such as starting and stopping. This is because when the supply of gas to the fuel cell is stopped, the concentration difference of the reaction gas component occurs at the inlet and outlet of the cell, and the electrode is oxidized by the local battery formed by the concentration difference, resulting in deterioration. This phenomenon is also difficult to avoid in the conventional fuel cell configuration in which the fuel and oxidant supply ports and the discharge ports are separated from each other.

  In order to solve the above problems, it is effective to make the reaction gas supply port and the discharge port as close as possible. As a configuration in which the reaction gas supply port and the discharge port are close to each other in the prior art, a comb-shaped channel is raised. The comb-shaped channel is a channel in which two comb teeth are overlapped so that the teeth do not overlap, and one tooth is connected to the supply port and the other tooth is connected to the discharge port.

JP 2004-146309 A

  However, in the configuration of the comb-shaped channel, the supply-side channel and the discharge-side channel seem to be close to each other with the rib portion between them. Therefore, the supply port and the discharge port are essentially located at the same distance as the conventional fuel cell described above. For this reason, it is difficult to solve the problems of conventional fuel cells in which the supply port and the discharge port are separated.

  In the comb-shaped channel, the reaction gas supply channel and the discharge channel are not directly connected, so that the reaction gas is a gas composed of a conductive porous material such as carbon paper in the non-connected portion (rib portion). It passes through the inside of the diffusion layer and moves from the supply channel side to the discharge channel side. Since porous materials such as carbon paper have variations in thickness and porosity, there is a tendency for variations in pressure loss to be larger than in the case where a reaction gas is allowed to flow through a flow path. Therefore, when a comb-shaped flow path is used in a fuel cell stack in which a plurality of cells are stacked, reaction gas distribution becomes uneven due to variations in pressure loss between cells, and in some cases, reaction gas shortage (gas shortage) The electrode suffers irreparable damage.

  An object of the present invention is to provide a fuel cell that prevents an imbalance in water distribution due to the presence of a supply port and a discharge port, a non-uniform state of a reaction gas concentration, or a gas shortage due to pressure loss variation in a comb-shaped channel Is to provide.

  The fuel cell according to the present invention is a fuel cell provided with a flow path for supplying a fuel gas to a fuel electrode having a cell formed by sandwiching an electrolyte having ion conductivity between a fuel electrode and an oxidant electrode. In a fuel cell that is sandwiched between an oxidant channel plate provided with a channel plate and a channel for supplying an oxidant gas to the oxidant electrode, the fuel channel plate or the oxidant channel plate At least one of the supply flow path and the discharge flow path disposed on the opposite surface not in contact with the corresponding electrode, and the supply hole that penetrates the flow path plate and connects to the supply flow path and the discharge flow path, respectively. In addition, a plurality of discharge holes and a plurality of connecting flow paths that are arranged in parallel on the electrode surfaces in contact with the corresponding electrodes and connect the supply holes and the discharge holes are provided on the electrode surfaces.

  The effect of the fuel cell according to the present invention is that at least one of the fuel flow path and the oxidant flow path is disposed on the opposite surface not in contact with the corresponding electrode and is not connected to the opposite surface. A plurality of supply holes and discharge holes that pass through the flow path plate and connect to the supply flow path and the discharge flow path, respectively, and are arranged in parallel on the electrode surfaces that contact the corresponding poles. And a discharge channel for connecting the discharge hole and the outlet of the reaction gas on the electrode surface and the inlet of the discharge hole are close to each other, so that the water distribution in the electrode surface can be made uniform. It is possible to prevent a decrease in battery performance due to non-uniformity.

Embodiment 1 FIG.
FIG. 1 is a configuration diagram of a fuel cell stack according to Embodiment 1 of the present invention.
In the fuel cell stack 1, a plurality of cells 2 are stacked via a fuel / oxidant partition plate 12 between them, a metal current collector plate 3 is provided at both ends of the stack, and insulating plates 4 are provided at both ends. The presser end plate 5 is disposed through the bolts and is integrated by tightening the presser end plate 5 using bolts and nuts (not shown).

FIG. 2 is a configuration diagram of a cell 2 constituting the fuel cell stack 1 according to the first embodiment.
This cell 2 includes a membrane electrode assembly (a fuel electrode 7 and an oxidant electrode 8 each composed of a gas diffusion layer composed of an electrolyte membrane 6 and a catalyst layer sandwiching the electrolyte membrane 6 and a conductive porous body). (Hereinafter abbreviated as “MEA”) 9. Further, the cell 2 includes a fuel-side flow path plate 10 and an oxidant-side flow path plate 11 that sandwich the MEA 9 from both sides.
The surface on the opposite side of the surface (hereinafter referred to as “electrode surface of the fuel-side flow channel plate 10”) of the fuel-side flow channel plate 10 (hereinafter referred to as “the surface opposite to the fuel-side flow channel plate 10”). The fuel / oxidant partition plate 12 is disposed on the opposite side of the surface of the oxidant side channel plate 11 that contacts the MEA 9 (hereinafter referred to as “electrode surface of the oxidant side channel plate 11”). The fuel / oxidant partition plate 12 is also disposed on this surface (hereinafter referred to as the “opposite surface of the oxidant side flow path plate 11”) to form an oxidant flow path. As the MEA 9, there is no need to adopt a special configuration for the present invention, and the well-known MEA 9 can be used as it is.

FIG. 3 is a flow channel detail view of the fuel side flow channel plate 10 which is a component of the cell 2 according to the first embodiment. FIG. 3A is a plan view of the electrode surface of the fuel side flow path plate 10. FIG. 3B is a plan view of the opposite surface of the fuel side flow path plate 10.
The fuel-side flow path plate 10 is a fluid for controlling the temperature of the fuel cell stack 1 such as a fuel supply manifold 21, a fuel discharge manifold 22, an oxidant supply manifold 23, an oxidant discharge manifold 24, and cooling water that penetrates in the thickness direction. Is provided with a temperature control fluid supply manifold 25 for supplying the fluid and a temperature control fluid discharge manifold 26 for discharging the fluid for temperature control.

  The fuel-side flow path plate 10 has a fuel supply distribution flow path 71 for uniformly distributing fuel from the fuel supply manifold 21 to the opposite surface, and a fuel supply flow path for supplying fuel to the entire opposite surface to the opposite surface. 72, a fuel supply hole 73 penetrating the fuel side flow path plate 10 in the thickness direction for supplying fuel from the fuel supply flow path 72 to the electrode surface, and a fuel side flow for discharging unconsumed fuel from the electrode surface A fuel discharge hole 75 penetrating the road plate 10 in the thickness direction, a fuel connection passage 74 connecting the fuel supply hole 73 and the fuel discharge hole 75 within the electrode surface, and an unexposed surface discharged from each fuel discharge hole 75 A fuel discharge passage 76 for collecting consumed fuel and a fuel discharge collection passage 77 for collecting unconsumed fuel discharged from each fuel discharge passage 76 and discharging them to the fuel discharge manifold 22 are provided on the opposite surface. ing.

The fuel supply flow path 72 and the fuel discharge flow path 76 have a comb-tooth structure, and the fuel supply flow path 72 and the fuel discharge flow path 76 are arranged so that their teeth mesh with each other.
The fuel supply hole 73 and the fuel discharge hole 75 are provided at equal intervals in the direction in which the fuel gas flows. In addition, you may change along the direction which flows a space | interval.
In this way, the fuel supply flow path 72 and the fuel discharge flow path 76 having a comb-tooth structure are arranged so that their teeth mesh with each other, and a fuel supply hole 73 and a fuel discharge hole 75 are provided in each tooth. Therefore, the space between the fuel supply hole 73 and the fuel discharge hole 75 can be shortened.
Further, the fuel side flow path plate 10 is provided with a temperature control fluid flow path 90 that meanders so as to sew between the fuel supply flow path 72 and the fuel discharge flow path 76 on the opposite surface.

FIG. 4 is a detailed flow path diagram of the oxidant side flow path plate 11 which is a component of the cell 2 according to the first embodiment. FIG. 4A is a plan view of the opposite surface of the oxidant side flow path plate 11. FIG. 4B is a plan view of the electrode surface of the oxidant side flow path plate 11.
The oxidant side flow path plate 11 includes a fuel supply manifold 21, a fuel discharge manifold 22, an oxidant supply manifold 23, an oxidant discharge manifold 24, a temperature control fluid supply manifold 25, and a temperature control fluid discharge manifold 26. It is provided so as to penetrate the plate 11 in the thickness direction.

  Further, the oxidant side flow channel plate 11 supplies an oxidant supply distribution channel 81 for uniformly distributing the oxidant from the oxidant supply manifold 23 to the opposite surface, and supplies the oxidant to the entire opposite surface on the opposite surface. In order to supply fuel from the oxidant supply channel 82 to the electrode surface, the oxidant supply hole 83 penetrating the oxidant side channel plate 11 in the thickness direction and unused from the electrode surface In order to discharge the oxidant, the oxidant discharge hole 85 that penetrates the oxidant side flow path plate 11 in the thickness direction, the oxidant supply hole 83 and the oxidant discharge hole 85 are connected in the electrode plane. An oxidant discharge channel 86 for collecting unused oxidants discharged from the oxidant discharge holes 85 on the opposite surface, and an unused oxidant discharged from each oxidant discharge channel 86 on the opposite surface. Then, the oxidant discharge collecting flow path 8 for discharging to the oxidant discharge manifold 24 It is provided.

The oxidant supply flow path 82 and the oxidant discharge flow path 86 have a comb structure, and the oxidant supply flow path 82 and the oxidant discharge flow path 86 are arranged so that their teeth mesh with each other.
The oxidant supply hole 83 and the oxidant discharge hole 85 are provided at equal intervals in the direction in which the oxidant gas flows. In addition, you may change along the direction which flows a space | interval.
Thus, the oxidant supply channel 82 and the oxidant discharge channel 86 having a comb-tooth structure are arranged so that their teeth mesh with each other, and an oxidant supply hole 83 and an oxidant discharge hole 85 are formed in each tooth. Since it is provided, the space between the oxidant supply hole 83 and the oxidant discharge hole 75 can be shortened.

FIG. 5 is a detailed flow path diagram of the fuel / oxidizer partition plate 12 according to the first embodiment. FIG. 5A is a plan view of a surface in contact with the fuel side flow path plate 10. FIG. 5B is a plan view of a surface in contact with the oxidant side flow path plate 11.
The fuel / oxidant separator 12 includes a fuel supply manifold 21, a fuel discharge manifold 22, an oxidant supply manifold 23, an oxidant discharge manifold 24, a temperature control fluid supply manifold 25, and a temperature control fluid discharge manifold 26. It is provided so as to penetrate the plate 12 in the thickness direction.

FIG. 6 is a cross-sectional view of the cell 2 in which the MEA 9, the fuel side flow path plate 10, the oxidant side flow path plate 11, and the fuel / oxidant partition plate 12 are laminated. Note that this cross-sectional view is a cross-sectional view taken along the line AA of FIGS. 3, 4, and 5.
Next, the flow of the reaction gas during power generation will be described with reference to FIGS.
First, fuel is distributed and supplied to each cell 2 constituting the fuel cell stack 1 through the fuel supply manifold 21. The fuel supplied to each cell 2 is uniformly distributed to the plurality of fuel supply channels 72 from the fuel supply manifold 21 via the fuel supply distribution channel 71. The fuel supplied to the fuel supply channel 72 is further divided into a plurality of parts and supplied to the fuel electrode 7 of the MEA 9 through the fuel supply hole 73. On the surface where the fuel side flow path plate 10 is in contact with the fuel electrode 7, the fuel flows along the fuel connection flow path 74 and is electrochemically reduced to protons to be consumed. Unconsumed fuel (including moisture) is discharged from the fuel connection flow path 74 to the fuel discharge hole 75, and then the flow of the plurality of fuel discharge holes 75 is gathered in the fuel discharge flow path 76, and a plurality of fuels are further collected. After the flow of the discharge flow path 76 is collected in the fuel discharge collecting flow path 77, it is discharged to the outside of the fuel cell stack 1 through the fuel discharge manifold 22.

  On the other hand, the oxidizing agent is distributed and supplied to each cell 2 constituting the fuel cell stack 1 through the oxidizing agent supply manifold 23. The oxidant supplied to each cell 2 is uniformly distributed from the oxidant supply manifold 23 to the plurality of oxidant supply flow paths 82 via the oxidant supply distribution flow path 81. The oxidant supplied to the oxidant supply channel 82 is further divided into a plurality of parts and supplied to the oxidant electrode 8 of the MEA 6 through the oxidant supply hole 83. On the surface where the oxidant side flow path plate 11 is in contact with the oxidant electrode 8, the oxidant flows along the oxidant connection flow path 84, and the oxidant is consumed by electrochemically oxidizing protons. When the oxidant is air, oxygen in the air is reduced to produce water. Unused oxidant and moisture generated by the reaction are discharged from the oxidant connection channel 84 to the oxidant discharge hole 85, and then the flow of the plurality of oxidant discharge holes 85 is collected in the oxidant discharge channel 86. Further, after the flows of the plurality of oxidant discharge passages 86 are gathered in the oxidant discharge collecting passage 87, they are discharged to the outside of the fuel cell stack 1 through the oxidant discharge manifold 24.

  Conventionally, in a fuel cell using air as an oxidant, water is generated between an oxidant connection channel 84 that contacts the oxidant electrode 8, that is, between the outlet of the oxidant supply hole 83 and the inlet of the oxidant discharge hole 85. For this reason, water is unevenly present on the inlet side of the oxidant discharge hole 85. When the distance between the inlet of the oxidant discharge hole 85 and the outlet of the oxidant supply hole 83 is large, the water distribution between the outlet of the oxidant supply hole 83 and the inlet of the oxidant discharge hole 85 is made uniform. Since it is difficult to carry out, there exists a problem that reaction becomes non-uniform | heterogenous and battery performance falls.

On the other hand, in the first embodiment, the oxidant supply flow path 82 and the oxidant discharge flow path 86 are provided on the opposite surface of the oxidant side flow path plate 11. And the oxidant discharge passage 86 are not connected, and are connected by a short oxidant connection passage 84 provided on the surface in contact with the MEA 9, so that the outlet of the oxidant supply hole 83 and the oxidant discharge hole 85 are connected. As the inlet approaches, the bias of water hardly occurs at the inlet of the oxidant discharge hole 85 and it is easy to make uniform. As a result, the reaction occurs uniformly in the electrode surface, so that the electrode performance is improved.
In particular, in the low humidification operation in which the bias of water increases between the oxidant supply hole 83 and the oxidant discharge hole 85, that is, in the operation in which the reaction gas is humidified to a dew point lower than that of the fuel cell, the effect of this equalization is increased. The battery performance is further improved.
In the fuel side passage plate 10 as well, the fuel supply hole 73 and the fuel discharge hole 75 are connected by a short fuel connection flow path 74, so that the outlet of the fuel supply hole 73 and the inlet of the fuel discharge hole 75 are connected. And the bias of water does not easily occur at the inlet of the fuel discharge hole 75 and is easy to make uniform.

Thus, it can be seen that it is desirable that the outlet of the oxidizing agent supply hole 83 and the inlet of the oxidizing agent discharge hole 85 be as close as possible. That is, it is desirable that the oxidant connection channel 84 that connects the oxidant supply hole 83 and the oxidant discharge hole 85 has a configuration with the shortest possible length. However, if it is too short, the pressure loss in the flow path will be too small, and this may cause uneven gas distribution. Therefore, it is necessary to optimize the flow path length and cross-sectional area in consideration of this point. There is.
Specifically, the fuel connection flow path 74, the oxidant connection flow, and the fuel supply flow path 72, the oxidant supply flow path 82, the fuel discharge flow path 76, and the oxidant supply flow path 86 provided on the surface not in contact with the MEA 9 are provided. It is preferable to narrow the path 84.

  Further, the outlet of the fuel supply hole 73 and the inlet of the oxidant discharge hole 85, and the inlet of the fuel discharge hole 75 and the outlet of the oxidant supply hole 83 are configured to face each other via the MEA 9, so On the other hand, the oxidizing agent flows oppositely through the MEA 9 (hereinafter, the oppositely flowing flow is referred to as an opposing flow). In the counterflow, water accumulated at the inlet of the oxidant discharge hole 85 moves to the outlet of the fuel supply hole 73 via the MEA 9 and reaches the fuel discharge hole 75 through the fuel connection channel 74. The water that has reached the fuel discharge hole 75 again moves to the outlet of the oxidant supply hole 83 via the MEA 9. As a result, there is an effect that the water distribution in the electrode surface is further uniformized.

  Thus, it is desirable that the fuel and the oxidant flow in opposite directions. However, since the water distribution changes depending on the temperature distribution of the battery, the counter flow is not necessarily optimal in any case. Select according to the battery characteristics, such as a parallel flow in which the fuel and oxidant supply holes and discharge holes face each other, or a cross flow in which the fuel connection channel 74 and the oxidant connection channel 84 are perpendicular to each other across the MEA 9. It is possible.

  In general, when a gas different from the gas that stays inside the battery when the fuel cell is started is supplied, for example, when fuel (hydrogen) is supplied in a state where the bipolar flow path inside the battery is filled with air, the gas at the inlet and outlet Since the composition is different, an electromotive force is generated by a local battery reaction, and there is a phenomenon that the electrode is oxidized by this electromotive force and the battery is deteriorated. In the conventional fuel cell, since the inlet and the outlet are far apart, it is difficult to make the gas composition at the inlet and the outlet uniform.

  However, in the first embodiment, since the distance between the inlet and the outlet is short, even if there is a difference in the concentration of the reaction gas between the inlet and the outlet, it is easy to make it uniform by diffusion or the like. effective. As a result, it is possible to provide a fuel cell with little deterioration even after repeated start and stop.

  In the first embodiment, the supply flow channel and the discharge flow channel are provided on a surface different from the surface in contact with the electrode. Therefore, in the conventional battery, the temperature control fluid flow channel disposed on the other surface. The arrangement of 90 is limited. As a result, there is a concern that the number of flow path plates doubles compared to the conventional case. However, for example, by arranging the temperature control fluid flow path 90 so as to sew between the fuel supply flow path 72 and the fuel discharge flow path 76, an increase in the flow path plate can be minimized.

  In the first embodiment, the temperature control fluid channel 90 is arranged so as to sew between the fuel supply channel 72 and the fuel discharge channel 76 arranged on the surface not in contact with the electrode. It is also possible to separately install a flow path plate for the use flow path. In this case, there is a demerit that the number of flow path plates is newly increased. However, since the flow path of the temperature control fluid can be freely arranged in the electrode surface, more advanced temperature control is possible.

Embodiment 2. FIG.
The fuel cell according to the second embodiment of the present invention is different from the fuel cell according to the first embodiment in the oxidant side flow path plate 11B, and the other portions are the same. The description is omitted. FIG. 7 is a plan view of the opposite surface of the oxidant side flow path plate according to Embodiment 2 of the present invention.
The oxidant supply channel 82 and the oxidant discharge channel 86 according to the first embodiment are linear comb-shaped channels, but the oxidant supply channel 82B and the oxidant discharge channel according to the second embodiment. 86B is a spiral channel as shown in FIG. 7A, and the oxidant supply channel 82B and the oxidant discharge channel 86B are not connected to each other on the opposite surface.
Note that a meandering flow path may be used as shown in FIG.
Further, regarding the fuel supply flow path 72 and the fuel discharge flow path 76 provided on the opposite surfaces of the fuel side flow path plate 10, if the fuel supply flow path 72 and the fuel discharge flow path 76 are not connected on the opposite surfaces, It may be spiral or serpentine.

Embodiment 3 FIG.
In the first embodiment, the fuel electrode 7 is in contact with the electrode surface of the fuel side passage plate 10, the fuel connection passage 74 is provided on the electrode surface, and the fuel supply passage 72 and the fuel discharge passage 76 are provided on the opposite surfaces. However, in the third embodiment, two fuel side flow path plates are used, the fuel connection flow path 74 is provided on one side of one fuel side flow path plate, and the other side of the fuel side flow path plate is provided. A fuel supply channel 72 and a fuel discharge channel 76 are provided.

Embodiment 4 FIG.
FIG. 8 is a detailed flow path diagram of the fuel / oxidant separator 12D according to the fourth embodiment of the present invention. FIG. 8A is a plan view of a surface in contact with the fuel side flow path plate 10D. FIG. 8B is a plan view of a surface in contact with the oxidant side flow path plate 11D. FIG. 9 is a plan view of the opposite surface of the fuel side flow path plate 10D according to the fourth embodiment. FIG. 10 is a plan view of the opposite surface of the oxidant side flow path plate 11D according to the fourth embodiment. FIG. 11 is a cross-sectional view of a cell in which MEA 9, fuel side flow path plate 10D, oxidant side flow path plate 11D, and fuel / oxidant partition plate 12D are stacked in the fourth embodiment. This cross-sectional view is a cross-sectional view taken along the line BB in FIGS. 8, 9, and 10.
The fuel cell according to the fourth embodiment of the present invention is different from the fuel cell according to the first embodiment in the fuel side flow path plate 10D, the oxidant side flow path plate 11D, and the fuel / oxidant partition plate 12D. Since the other parts are the same, the same reference numerals are attached to the same parts and the description thereof is omitted.
As shown in FIG. 9, the fuel side flow path plate 10D according to the fourth embodiment is different from the fuel side flow path plate 10 according to the first embodiment. 72, the fuel discharge flow path 76, and the fuel discharge collective flow path 77 are omitted.
Further, the oxidant side flow path plate 11D according to the fourth embodiment is different from the oxidant side flow path plate 11 according to the first embodiment, as shown in FIG. The oxidant supply flow path 82, the oxidant discharge flow path 86, and the oxidant discharge collective flow path 87 are omitted.
On the other hand, as shown in FIG. 8, the fuel / oxidizer partition plate 12D according to the fourth embodiment has a fuel supply / distribution channel 71 for distributing fuel uniformly from the fuel supply manifold 21 on one surface, and fuel. A fuel supply passage 72 for supplying the entire electrode surface, a fuel discharge passage 76 for collecting unconsumed fuel discharged from each fuel discharge hole 75, and an unconsumed fuel discharged from each fuel discharge passage 76 Thus, a fuel discharge collective flow path 77 for discharging to the fuel discharge manifold 22 is added. Further, a temperature control fluid flow path 90 that is meandering so as to sew a non-connected portion between the fuel supply flow path 72 and the fuel discharge flow path 76 is added to the one surface.
Further, the fuel / oxidant partition plate 12D according to the fourth embodiment has an oxidant supply / distribution flow path 81 for uniformly distributing the oxidant from the oxidant supply manifold 23 to the other surface, and the oxidant over the entire electrode surface. An oxidant supply flow path 82 for supplying the oxidant, an oxidant discharge flow path 86 for collecting unused oxidants discharged from the respective oxidant discharge holes 85, and an unused oxidation discharged from each oxidant discharge flow path 86. An oxidant discharge collecting flow path 87 for collecting the agents and discharging them to the oxidant discharge manifold 24 is added.

Embodiment 5. FIG.
FIG. 12 is a detailed flow path diagram of the oxidant side flow path plate 11E according to the fifth embodiment of the present invention. FIG. 12A is a plan view of the opposite surface of the oxidant side flow path plate 11E. FIG. 12B is a plan view of the electrode surface of the oxidant side flow path plate 11E. FIG. 13 is a cross-sectional view of a cell in which MEA 9, fuel side flow path plate 10E, oxidant side flow path plate 11E and fuel / oxidant partition plates 12 and 12E are stacked in the fifth embodiment. This sectional view is a sectional view taken along the line CC in FIG.
The fuel cell according to the fifth embodiment of the present invention is different from the fuel cell according to the first embodiment in the fuel side flow path plate 10E, the oxidant side flow path plate 11E, and the fuel / oxidant partition plate 12E. Since it is the same, the same code | symbol is attached | subjected to the same part and description is abbreviate | omitted.
The fuel side flow path plate 10E according to the fifth embodiment is different from the fuel side flow path plate 10 according to the first embodiment in the fuel connection flow path 74E, and the fuel supply hole 73 and the fuel discharge hole 75 are omitted. Since other than that is the same, the same code | symbol is attached | subjected to the same part and description is abbreviate | omitted.
Further, as shown in FIG. 12, the oxidant side flow path plate 11E according to the fifth embodiment is different from the oxidant side flow path plate 11 according to the first embodiment in the oxidant connection flow path 84E, and the oxidant supply path 84E is different. Since the hole 83 and the oxidant discharge hole 85 are omitted, and the other parts are the same, the same portions are denoted by the same reference numerals and the description thereof is omitted.
As shown in FIG. 13, the fuel connection flow path 74E according to the fifth embodiment penetrates the fuel side flow path plate 10E in the thickness direction, and connects the fuel supply flow path 72 and the fuel discharge flow path 76.
Further, the oxidant connection flow path 84E according to the fifth embodiment penetrates the oxidant side flow path plate 11E in the thickness direction, and connects the oxidant supply flow path 82 and the oxidant discharge flow path 86.

  In this case, since the temperature control fluid flow channel 90 cannot be disposed on the opposite surface provided with the fuel supply flow channel 72 and the fuel discharge flow channel 76, it is necessary to newly install it on another surface, but the surface in contact with the electrode Since a drilled product such as punching metal can be used for the flow path plate disposed in the plate, there is a possibility that it can be manufactured at low cost. As the metal used as the flow path plate, any material having conductivity can be used, but a corrosion-resistant material such as stainless steel, titanium, or a metal plate coated with a corrosion-resistant coating such as a noble metal, carbon A material having conductivity and corrosion resistance such as a plate can be used.

Embodiment 6 FIG.
FIG. 14 is a plan view of the opposite surface of the fuel side flow path plate 10F according to Embodiment 6 of the present invention. FIG. 15 is a plan view of the opposite surface of the oxidant side flow path plate 11F according to the sixth embodiment of the present invention.
The fuel cell according to the sixth embodiment of the present invention is different from the fuel cell according to the first embodiment in the fuel side flow channel plate 10F and the oxidant side flow channel plate 11F. Are denoted by the same reference numerals and description thereof is omitted.
The fuel side flow path plate 10F according to the sixth embodiment is different from the fuel side flow path plate 10 according to the first embodiment, except for the fuel supply flow path 72F and the fuel discharge flow path 76F. The same reference numerals are attached to the parts, and the description is omitted.
Further, the oxidant side flow path plate 11F according to the sixth embodiment is different from the oxidant side flow path plate 11 according to the first embodiment in the oxidant supply flow path 82F and the oxidant discharge flow path 86F. Since it is the same, the same code | symbol is attached | subjected to the same part and description is abbreviate | omitted.

The fuel supply flow path 72 and the fuel discharge flow path 76 according to the first embodiment have a constant cross-sectional area, but the fuel supply flow path 72F and the fuel discharge flow path 76F according to the sixth embodiment are shown in FIG. As described above, the cross-sectional area changes depending on the position.
Further, the oxidant supply flow path 82 and the oxidant discharge flow path 86 according to the first embodiment have a constant cross-sectional area, but the oxidant supply flow path 82F and the oxidant discharge flow path 86F according to the sixth embodiment. As shown in FIG. 15, the cross-sectional area changes depending on the position.

Hereinafter, the effect will be described with respect to the oxidant side flow plate 11F, but the same effect can be obtained with respect to the fuel side flow plate 10F.
As shown in FIG. 15, the oxidant supply flow path 82F provided on the opposite surface of the oxidant side flow path plate 11F branches into a large number of oxidant connection flow paths 84 as the gas advances from upstream to downstream. Therefore, the flow velocity is different between upstream and downstream, and uniform gas distribution becomes difficult, and problems such as easy accumulation of water in a portion where the flow velocity is slow may occur. In order to solve this, it is effective to gradually narrow the flow path from the upstream side to the downstream side. As a result, the flow velocity on the downstream side is increased, and there is an effect of preventing water accumulation and making gas distribution uniform.

On the other hand, in the oxidant discharge channel 86, as the number of oxidant connection channels 84 merges from upstream to downstream, it is effective to gradually increase the thickness of the channel.
Various methods to change the cross-sectional area depending on the position, such as changing the number of channels by increasing the depth of the groove to narrow the groove width or merging multiple channels, are adopted as methods for changing the cross-sectional area. Is possible.
The thicknesses of the oxidant supply channel 82 and the oxidant discharge channel 86 need not be the same, and an optimal cross-sectional configuration can be selected according to the operating conditions.

Embodiment 7 FIG.
FIG. 16 is a plan view of an electrode surface of a fuel side flow path plate 10G according to Embodiment 7 of the present invention. FIG. 17 is a plan view of the electrode surface of the oxidant side flow path plate 11G according to Embodiment 7 of the present invention.
The fuel cell according to the seventh embodiment of the present invention is different from the fuel cell according to the first embodiment in the fuel side flow channel plate 10G and the oxidant side flow channel plate 11G. Are denoted by the same reference numerals and description thereof is omitted.
The fuel side flow path plate 10G according to the seventh embodiment is different from the fuel side flow path plate 10 according to the first embodiment except for the fuel connection flow path 74G, and the other parts are the same. Additional description will be omitted.
Further, the oxidant side flow channel plate 11G according to the seventh embodiment is different from the oxidant side flow channel plate 11 according to the first embodiment in terms of the oxidant connection flow channel 84G, and the rest is the same. The same reference numerals are given to the portions, and the description is omitted.

The cross-sectional area of the fuel connection channel 74 according to the first embodiment is constant, but the cross-sectional area of the fuel connection channel 74G according to the seventh embodiment varies depending on the position as shown in FIG. .
The oxidant connection channel 84 according to the first embodiment has a constant cross-sectional area, but the oxidant connection channel 84G according to the seventh embodiment has a cross-sectional area depending on the position as shown in FIG. It has changed.

In the fuel connection flow path 74 having a constant cross-sectional area, hydrogen is consumed along the flow of gas during power generation, so that the flow rate is reduced and as a result, the flow velocity is reduced. On the other hand, the flow velocity on the downstream side can be improved by reducing the cross-sectional area of the flow path as it goes downstream.
Similarly, oxygen is consumed in the oxidant connection channel 84, but water (steam) is generated, so it cannot be said that the flow rate is generally reduced. However, in the high humidification operation, the flow velocity in the downstream portion is not sufficiently increased, and a water pool is likely to be generated. Therefore, it may be effective to narrow the flow path in order to increase the flow velocity in the downstream portion.
The thicknesses of the oxidant connection channel 84 and the fuel connection channel 74 do not need to be the same, and an optimal cross-sectional configuration can be selected according to the operating conditions.
Various methods to change the cross-sectional area depending on the position, such as changing the number of channels by increasing the depth of the groove to narrow the groove width or merging multiple channels, are adopted as methods for changing the cross-sectional area. Is possible.

Embodiment 8 FIG.
FIG. 18 is a plan view of the electrode surface of the fuel side flow path plate 10H according to the eighth embodiment of the present invention.
The fuel cell according to the eighth embodiment of the present invention is different from the fuel cell according to the first embodiment in the fuel side flow path plate 10H, and the other parts are the same. Is omitted.
The fuel-side flow path plate 10H according to the eighth embodiment is different from the fuel-side flow path plate 10 according to the first embodiment except for the fuel connection flow path 74H. Additional description will be omitted.
The oxidant side flow path plate according to the eighth embodiment is the same as that of the first embodiment.

  The fuel connection channel 74 according to the first embodiment has a constant sectional area, but the fuel connection channel 74H according to the eighth embodiment meanders as shown in FIG. The meandering fuel connection flow path 74H has a fuel supply hole 73 and a fuel discharge hole 75 formed at both ends thereof, and a fuel supply flow path formed on the opposite side of the fuel side flow path plate 10H. Each communicates with a fuel discharge channel.

The fuel connection flow path 74H configured in this way can increase the pressure loss because the flow path length can be increased without greatly separating the distance between the fuel supply hole 73 and the fuel discharge hole 75. it can. As a result, the gas distribution amount from the fuel supply flow path to each fuel connection flow path can be made uniform.
Although the fuel connection flow path 74H is meandered in the fuel side flow path plate 10H according to the eighth embodiment, the same configuration may be adopted for the oxidant side flow path plate. Also in this case, the gas distribution amount from the oxidant supply channel to each oxidant supply channel can be made uniform.

It is a block diagram of the fuel cell stack concerning Embodiment 1 of this invention. It is a block diagram of the cell concerning Embodiment 1 of this invention. It is a flow path detailed drawing of the fuel side flow path board concerning Embodiment 1 of this invention. It is a flow-path detail drawing of the oxidizing agent side flow-path board concerning Embodiment 1 of this invention. FIG. 3 is a detailed flow diagram of the fuel / oxidizer partition according to the first embodiment of the present invention. It is sectional drawing of the cell concerning Embodiment 1 of this invention. It is a top view of the opposite surface of the oxidizing agent side flow path board concerning Embodiment 2 of this invention. It is a detailed block diagram of the fuel / oxidizer partition concerning Embodiment 4 of this invention. It is a top view of the opposite surface of the fuel side flow path board concerning Embodiment 4 of this invention. It is a top view of the opposite surface of the oxidizing agent side flow path board concerning Embodiment 4 of this invention. It is sectional drawing of the cell concerning Embodiment 4 of this invention. It is a flow-path detail drawing of the oxidizing agent side flow-path board concerning Embodiment 5 of this invention. It is sectional drawing of the cell concerning Embodiment 5 of this invention. It is a top view of the opposite surface of the fuel side flow path board concerning Embodiment 6 of this invention. It is a top view of the opposite surface of the oxidizing agent side flow path board concerning Embodiment 6 of this invention. It is a top view of the electrode surface of the fuel side flow path board concerning Embodiment 7 of this invention. It is a top view of the electrode surface of the oxidizing agent side flow path board concerning Embodiment 7 of this invention. It is a top view of the electrode surface of the fuel side flow path board concerning Embodiment 8 of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Fuel cell stack, 2 cells, 3 Current collector plate, 4 Insulating plate, 5 Holding end plate, 6 Electrolyte membrane, 7 Fuel electrode, 8 Oxidant electrode, 9 Membrane electrode assembly (MEA), 10 Fuel side flow path plate 11 Oxidant side flow path plate, 12 Fuel / oxidant partition plate, 21 Fuel supply manifold, 22 Fuel discharge manifold, 23 Oxidant supply manifold, 24 Oxidant discharge manifold, 25 Temperature control fluid supply manifold, 26 Temperature control fluid Discharge manifold, 71 Fuel supply distribution path, 72 Fuel supply flow path, 73 Fuel supply hole, 74 Fuel connection flow path, 75 Fuel discharge hole, 76 Fuel discharge flow path, 77 Fuel discharge collective flow path, 81 Oxidant supply distribution Channel, 82 Oxidant supply channel, 83 Oxidant supply hole, 84 Oxidant connection channel, 85 Oxidant discharge hole, 86 Oxidant discharge channel, 87 Oxidant discharge collection Combined flow path, 90 Temperature control fluid flow path.

Claims (6)

A fuel-side flow path plate provided with a flow path for supplying fuel gas to the fuel electrode, and a cell formed by sandwiching an electrolyte having ion conductivity between the fuel electrode and the oxidant electrode, and the oxidation In a fuel cell that is sandwiched by a channel plate on the oxidant side provided with a channel for supplying an oxidant gas to the electrode of the agent,
At least one of the fuel-side flow path plate and the oxidant-side flow path plate passes through the supply flow path and the discharge flow path disposed on the opposite surfaces not in contact with the corresponding poles. A plurality of supply holes and discharge holes that are connected to the supply flow path and the discharge flow path, respectively, are connected in parallel to electrode surfaces that are in contact with the corresponding poles, and are connected flows that connect the supply holes and the discharge holes on the electrode surfaces. A fuel cell, characterized in that a path is provided.   2. The fuel cell according to claim 1, wherein the supply flow path and the discharge flow path have a comb-tooth structure and are arranged so that their teeth mesh with each other.   The outlet of the supply hole and the inlet of the discharge hole in the electrode surface in contact with the fuel electrode of the fuel side flow path plate are respectively in the electrode surface in contact with the oxidant electrode of the oxidant side flow path plate. The fuel cell according to claim 1, wherein an inlet of the discharge hole and an outlet of the supply hole face each other with the electrolyte interposed therebetween.   The fuel cell according to claim 1, wherein a flow path for flowing a fluid for adjusting temperature is disposed between the supply flow path and the discharge flow path.   The cross-sectional area of the supply flow path is smaller downstream than upstream along the corresponding gas flow, or the cross-sectional area of the discharge flow path is downstream from upstream along the corresponding gas flow. The fuel cell according to claim 1, wherein the fuel cell is large.   2. The fuel cell according to claim 1, wherein a flow path cross-sectional area of the connection flow path is smaller in the downstream than in the upstream along the corresponding gas flow.

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