JP5292947B2 - Fuel cell - Google Patents

Description

  The present invention relates to a fuel cell.

  Conventionally, for example, as disclosed in Patent Document 1 below, fuel cells having various structures provided with a gas flow path and a refrigerant flow path are known. Spreading the reactant gas in a well-balanced manner in the plane of the fuel cell is important for maintaining a good power generation state and preventing partial depletion of the reactant gas. However, on the other hand, it is also important to keep the fuel cell in a favorable temperature state during power generation. For this reason, the gas flow path and the refrigerant flow path inside the fuel cell are ideally designed to satisfy both the gas supply function and the cooling function.

  In the above conventional technique, a gas flow path is formed using a porous body layer, and three plates are stacked to constitute one separator. Among the plates constituting the separator, a refrigerant flow plate provided with a large number of dimples protruding in the thickness direction is disposed in the central region of the intermediate plate. In the above conventional technology, the refrigerant is efficiently distributed within the fuel cell surface by flowing the refrigerant by sewing the gaps in the dimples.

JP 2006-318863 A JP 2006-127770 A

  By the way, conventionally, a fuel cell of a type in which a groove is provided on the surface of the separator and this groove is used as a gas flow path is known. In this type of fuel cell, generally, a gas diffusion sheet such as a carbon sheet and a membrane electrode assembly (MEA) are sequentially stacked on the surface of the separator where the groove is provided.

  In the fuel cell of the above-described type, a refrigerant flow path for flowing a refrigerant is provided on a surface of the separator that does not contact the gas diffusion sheet side (that is, a surface opposite to the formation surface of the gas flow channel groove). There is something. Specifically, for example, there is a fuel cell in which a metal plate is processed by press molding to create a plate having a concavo-convex shape on the front and back surfaces and this concavo-convex plate is used as a separator.

  In a fuel cell of a type that uses a concavo-convex plate as a separator, a gas channel and a refrigerant channel share a space in the separator surface. At this time, it is desirable to provide the gas flow path and the refrigerant flow path so that both the gas supply function and the cooling function are not impaired. However, it is not easy to arrange the gas flow path and the refrigerant flow path so as to satisfy both functions in a limited space in the separator surface.

  The present invention has been made to solve the above-described problems, and provides a fuel cell capable of achieving both a gas flow path and a refrigerant flow path in a limited space within a separator surface. Objective.

In order to achieve the above object, a first invention is a fuel cell,
A membrane electrode assembly having electrode catalyst layers on both sides of the electrolyte membrane;
A first gas diffusion sheet overlaid on the anode surface of the membrane electrode assembly; a second gas diffusion sheet overlaid on the cathode surface of the membrane electrode assembly;
An uneven shape that is superimposed on the first gas diffusion sheet, has a surface facing the first gas diffusion sheet side, and a back surface opposite to the surface, and the shape is reversed between the surface and the back surface. A first gas supply comprising: a first separator having a concave portion on the surface side used as a reaction gas flow path; and a second separator stacked on the back surface of the first separator. Members,
A second gas supply member provided with a porous body layer that is stacked on the second gas diffusion sheet and is in contact with the second gas diffusion sheet;
With
The concave-convex shape of the first separator is concave on the surface side, and a pattern when the first separator is viewed in plan is a comb-shaped first concave portion, and the first concave portion is concave on the front surface side. And a second recess that is spaced apart and has a comb shape in which the pattern of the first separator in plan view meshes with the first recess,
The second separator is in contact with the convex portion facing the first and second concave portions on the back side of the first separator, thereby forming a space between the first separator and
The first and second separators in a stacked state form a first opening that opens the space to the outside, and a second opening that opens the space to the outside at a position different from the first opening ,
Each of the first concave portion and the second concave portion includes a plurality of main branch portions branched in the comb shape, and a sub branch portion that is a plurality of concave portions further branched from the main branch portion,
Each of the end portions of the sub-branching portion terminates in a region where the first separator and the membrane electrode assembly overlap each other.

The second invention is the first invention, wherein
When the first separator is cut in a direction intersecting with the direction in which the first and second recesses mesh with each other in the power generation region of the fuel cell, the uneven shape of the first separator The bottom surface includes a portion whose width is larger than the width of the first recess and / or the second recess.

According to 1st invention, by making reaction gas flow in into a 1st recessed part, this reactive gas can be flowed in a 2nd recessed part via the inside of a gas diffusion sheet. By generating such a gas flow, the gas supply along the plane direction of the gas diffusion sheet can be satisfactorily performed. Furthermore, according to the first invention, a space formed by sewing between the first and second recesses on the back surface side of the first separator by flowing the refrigerant between the first and second openings is used as the refrigerant flow path. Can be used. Thereby, the in-plane of the fuel cell can be cooled. Thus, according to 1st invention, the limited space in a separator surface can be utilized effectively so that a gas supply function and cooling performance may be made compatible.
Further, according to the first invention, the gas flow path is formed by the porous layer on the cathode side, and the groove type gas flow path is provided on the anode side. It is possible to improve the performance of the entire fuel cell by properly using the groove type gas flow path and the gas flow path by the porous body layer having different characteristics in terms of gas diffusibility, drainage, and electrode contact area under the groove. .

  According to the second invention, the width of the bottom surface of the convex portion on the surface side (hereinafter also referred to as “peak side width”) is greater than the width of the concave portion on the surface side (hereinafter also referred to as “groove side width”). Has also been enlarged. The crest side width is a dimension that determines the width of a region where the first separator is in contact with the gas diffusion sheet. According to the second aspect of the invention, it is possible to increase the crest side width and increase the contact area between the first separator and the gas diffusion sheet. Since the gas supply along the plane direction of the gas diffusion sheet is satisfactorily performed by the effect of the first invention, a large contact area between the first separator and the gas diffusion sheet can be obtained without impairing the gas supply performance. Furthermore, since the first separator has an uneven shape on the front and back, the crest side width is also a dimension that determines the size of the space on the back side of the first separator. Therefore, a space through which the refrigerant flows can be increased as the contact area expands.

Embodiment 1 FIG.
[Configuration of Embodiment 1]
FIG. 1 is a plan view for explaining the configuration of the fuel cell 2 of the first embodiment. The fuel cell 2 includes a separator 20, a separator 30, a porous body layer 34, a gas diffusion sheet 14, a membrane electrode assembly (MEA) 10, a gas diffusion sheet 12, a separator 20, and a separator in a direction penetrating the paper surface of FIG. 1. Each member is laminated in the order of 30.

  In the present embodiment, the fuel cell 2 is configured as a fuel cell stack by repeatedly stacking the above laminated structure in the direction penetrating in FIG. That is, a laminated structure is repeatedly provided on the surface side of the paper in FIG. 1 such as the gas diffusion sheet 12, the MEA 10, and the gas diffusion sheet 14. Further, in FIG. 1, for convenience, the surface of the separator 20 is shown so as to be visible, but actually, stack end plates and the like are arranged at both ends in the stacking direction. In FIG. 1, a region E surrounded by a dotted line indicates a region used for a power generation reaction in the plane of the MEA 10 stacked on the separator 20. Hereinafter, it is referred to as a power generation region E.

  The MEA 10 includes an electrode catalyst layer on both sides of a proton conductive solid polymer electrolyte membrane. The gas diffusion sheets 12 and 14 are made of a carbon sheet or a carbon non-woven fabric. The gas diffusion sheets 12 and 14 function as a so-called gas diffusion layer.

  The separator 20 visible in FIG. 1 has a rectangular outer shape, and a plurality of through holes (through holes 26, 28, 29) are provided on the outer peripheral side. These through holes are provided in order to form various manifolds in the fuel cell stack. The separator 20 is formed by pressing one metal plate, and the uneven shape is inverted between the front surface and the back surface.

  The separator 20 includes a recess 22a that extends from the through hole 26 at the upper left of the drawing and a recess 22b that extends from the through hole 26 at the lower right of the drawing. The recesses 22a and 22b are both open on the front side of the sheet of FIG. As shown in FIG. 1, the recess 22 a has one recess that communicates with the through hole 26 and extends in the lateral direction of the paper surface, and a plurality of recesses that extend downward from the single recess. Similarly, the concave portion 22b has one concave portion that communicates with the through hole 26 and extends in the horizontal direction of the paper surface, and a plurality of concave portions that extend upward from the single concave portion. That is, in the fuel cell 2, when the separator 20 is viewed in plan, the recesses 22a and 22b have a comb-like pattern, and these two comb-like patterns are arranged so as to mesh with each other.

  As described above, the separator 20 has the concavo-convex shape inverted between the front surface and the back surface. That is, when the separator 20 is viewed from the back side of FIG. 1, the positions of the recesses 22a and 22b are on a business trip, and the position of the projection 24 is recessed. That is, when viewed from the back side of FIG. 1, the separator 20 is provided with a comb-like convex portion and a concave portion that meanders in the surface of the separator 20.

  As described above, the separator 30 is further stacked on the back side of the separator 20 in FIG. The separator 30 is a single flat plate and includes through holes 26, 28 and 29 at the same position as the separator 20. The material of the separator 30 is the same as that of the separator 20. Thus, in the first embodiment, the separators 20 and 30 constitute a separator assembly and function as a separator for the fuel cell 2.

  As described above, when viewed from the back side of FIG. 1, a recess that meanders in the surface of the separator 20 is provided. When the separator 20 and the separator 30 overlap with each other, the concave portion on the back surface side of the separator 20 is covered. As a result, a space that snakes in the surface of the separator 20 is formed between the separators 20 and 30. In FIG. 1, the direction in which this space extends is shown by meandering arrows. Although not shown in FIG. 1, actually, a sealing member is appropriately disposed between the separators 20 and 30, and the two through holes 29 are connected to this space. As a result, a continuous flow path is formed from the through hole 29 on the left side of the drawing to the through hole 29 on the right side of the drawing, as indicated by the meandering arrow shown in FIG. In the fuel cell 2, this space is used as a flow path for flowing the coolant. In the following description, the space is also referred to as “refrigerant flow path”.

FIG. 2 is a cross-sectional view of the fuel cell 2 when the fuel cell 2 is cut along the AA arrow line of FIG. As described above, the members in the order of the separator 20, the separator 30, the porous body layer 34, the gas diffusion sheet 14, the MEA 10, the gas diffusion sheet 12, the separator 20, and the separator 30 from the top to the bottom of the paper surface in FIG. 2. Are stacked. FIG. 3 is an exploded view of the individual members shown in the cross-sectional view of FIG. As shown in FIG. 3, in the first embodiment, the width _{W 1} of the convex portion 24, concave portion 22a, is larger than the width _{W 2} of 22b.

  The fuel cell 2 has a so-called groove-type gas flow path structure including the separators 20 and 30 in the anode side gas flow path structure, whereas the cathode side gas flow path structure includes the porous body layer 34. It is the type of gas flow path structure used. That is, different gas flow path structures are used for the anode and the cathode. Although not particularly shown in FIG. 1, the porous body layer 34 is actually connected to each of the two through holes 28 by appropriately arranging a sealing member. Specifically, for example, a seal frame is disposed so as to surround the outer periphery of the porous body layer 34. Since the technology itself for forming the gas flow path using the porous body layer is already a known technology, further explanation is omitted here.

[Operations and effects of the first embodiment]
When the fuel cell 2 generates power, high-pressure hydrogen gas is supplied to the recess 22a through a manifold formed by the through hole 26 at the upper left of FIG. On the other hand, the recess 22b is connected to the anode gas exhaust system of the fuel cell system via a manifold formed by a through hole 26 at the lower right of FIG. Further, the manifold formed by the through hole 29 is connected to a cooling system for circulating the coolant. As a result, the above-described refrigerant flow path is connected to the cooling system.

  The hydrogen gas supplied to the recess 22a flows into the adjacent recess 22b via the gas diffusion sheet 12 positioned on the front side of the separator 20 in FIG. In FIG. 1, such a flow of hydrogen gas is indicated by a number of arrows. Also in FIG. 2, the flow of hydrogen from the recess 22 a to the recess 22 b through the gas diffusion sheet 12 is illustrated by arrows. In the course of such a flow, hydrogen is supplied from the gas diffusion sheet 14 to the electrode catalyst layer of the anode of the MEA 10.

  The effects of the first embodiment will be described by comparing the fuel cell 2 with a conventional fuel cell having a groove type gas flow path. As the gas diffusion sheets 12 and 14, carbon sheets folded with carbon fibers are used. In general, the member used as the gas diffusion layer is often a member such as a carbon sheet or a carbon nonwoven fabric. When a separator having a groove-type gas flow path such as the recess 22a is attached to these members and gas is supplied to the groove-type gas flow path, the gas flow in the groove-type gas flow path is dominant. Become. If the recesses 22a and 22b are connected in the separator 20 surface, the recesses connect the two through holes 26. In the conventional groove-type gas flow path, continuous recesses (grooves) are provided in the separator surface as described above. In such a case, a large amount of hydrogen gas only flows through the recess, and hydrogen supply to the gas diffusion layer side is not smoothly performed. In this regard, in the fuel cell 2 of the first embodiment, as indicated by arrows in FIGS. 1 and 2, the hydrogen gas is forced into the gas diffusion sheet 12 in the process of flowing the hydrogen gas from the recess 22 a side to the recess 22 b side. Hydrogen flows through. For this reason, according to Embodiment 1, it is possible to smoothly supply hydrogen to the MEA 10 via the gas diffusion sheet 12.

  Further, during the power generation of the fuel cell 2, the coolant can flow from one through hole 29 to the other through hole 29 through the refrigerant flow path. As the coolant flows in this manner, the power generation region E of the fuel cell 2 is cooled. As described above, according to the fuel cell 2 of the first embodiment, the gas flow path and the refrigerant flow path can be arranged in a limited space in the separator 20 surface so as to satisfy both the gas supply function and the cooling function. it can.

  In particular, in the fuel cell 2, the coolant flows across the plane of FIG. 1 in the surface of the fuel cell 2. Further, in the fuel cell 2, after the hydrogen gas that has flowed into the recess 22 a from the through hole 26 flows in the horizontal direction in FIG. 1 in the plane of FIG. It has been introduced to the center side. As described above, according to the first embodiment, in the separator in which the concave and convex shapes on the front and back sides are reversed, the manifold arrangement is established such that the flow of the coolant and the flow of the hydrogen gas intersect in the surface of the fuel cell 2. ing.

According to the first embodiment, the fuel cell 2 also has the following two effects.
(I) Improvement of drainage performance of anode in fuel cell 2 (ii) Ensuring contact area between separator 20 and gas diffusion sheet 12 (reducing electrical resistance, ensuring sufficient surface pressure)
Hereinafter, individual effects will be described.

(I) Improvement of drainage performance of anode in fuel cell 2 In the first embodiment, the system for generating power in the fuel cell 2 includes an anode humidification mechanism for placing the anode of the fuel cell 2 in a good wet state. It shall be assumed. Specifically, the anode humidification mechanism is interposed between a hydrogen tank that stores hydrogen gas at a high pressure and the fuel cell 2, and humidifies the hydrogen gas or sprays water on the hydrogen gas. It can be. Further, in order to keep the anode in a good wet state, the MEA 10 may be configured using an electrolyte membrane of a type having a high back-refusion (reverse diffusion) function. Various techniques other than those described above are known for the anode humidification mechanism, and these techniques can be used. For this reason, further explanation is omitted.

  Keeping the anode in a good wet state is important in favoring the power generation reaction inside the fuel cell. However, on the other hand, if the amount of water present in the anode is excessive, power generation is hindered, and the power generation state is worsened. In the fuel cell 2 according to the first embodiment, as described above, a gas flow is generated in the gas diffusion sheet 12 in the direction of many arrows in FIG. With this gas flow, moisture can be swept away in the plane of the gas diffusion sheet 12 and discharged into the recess 22b. As a result, the drainage performance of the anode in the fuel cell 2 can be improved.

(Ii) Ensuring the contact area between the separator 20 and the gas diffusion sheet 12 (reducing electrical resistance, ensuring sufficient surface pressure)
The fuel cell 2 also has the following effects. As shown in FIG. 3, in the fuel cell 2, the width _{W 1} of the convex portion 24, the concave portion 22a, is larger than the width _{W 2} of 22b. According to such a configuration, a region where the convex portion 24 is in contact with the gas diffusion sheet 12 (hereinafter also referred to as “contact region”) is a region where the concave portions 22a and 22b are open to the gas diffusion sheet 12 (hereinafter referred to as “opening”). It becomes larger than the “region”).

  The width of the opening region corresponds to the width of the groove type gas channel obtained by the recesses 22a and 22b. In general, in a fuel cell of a type having a groove-type gas flow path, this opening region is often set wide in order to sufficiently supply a reaction gas to the gas diffusion layer side. That is, from the viewpoint of supply of the reaction gas, it is desired to provide an opening region as wide as possible in the space in the separator 20 surface.

On the other hand, the width of the contact area corresponds to the size of the area where the separator 20 contacts the gas diffusion sheet 12. As described above, the separator 20 is made of metal and also functions as a current collector plate in the fuel cell 2. The wider the contact area, the smaller the contact resistance between the separator 20 and the gas diffusion sheet 12, and the smaller the electric resistance inside the fuel cell 2. Therefore, from the viewpoint of efficiently extracting the power generated by the fuel cell 2, the contact area is desired to be widened. As described above, the fuel cell 2 is a fuel cell stack configured by repeatedly sandwiching the stacked structure shown in FIG. A fastening force is applied to both ends of the fuel cell stack so as to sandwich the individual members to be stacked. From the viewpoint of applying a surface pressure to the gas diffusion sheet 12, it is desired to take a wider contact area. Also, if assuming that was smaller design of the width W ₁ so as to widen the opening area, the convex portion 24 is distorted largely gas diffusion sheet 12 by the pressing when the pressing the gas diffusion sheet 12. In order to suppress the distortion of the gas diffusion sheet 12, it is desired to spread the contact pressure over a wide contact area.

  As described above, it is preferable that both the opening area and the contact area be wide in the separator surface. However, the space in the separator surface is limited.

Therefore, in the first embodiment, repeated separator 20 having a recess 22a, 22b with respect to the gas diffusion sheet 12, on its, taking the larger the width W ₁ so as to increase the contact area with priority. As described above, according to the fuel cell 2, in the separator 20, by flowing hydrogen gas into the recess 22a, the hydrogen gas is forced to pass through the gas diffusion sheet 12 and into the recess 22b. It can flow. By generating such a gas flow, gas supply along the planar direction of the gas diffusion sheet 12 can be performed satisfactorily. Therefore, according to the fuel cell 2, even if the opening area is made somewhat small, the function of gas supply is not impaired. That is, in the fuel cell 2, a wide contact area is ensured without impairing the gas supply function. As a result, in the fuel cell 2, the effects of reducing the contact resistance, applying the surface pressure, and reducing the distortion of the gas diffusion sheet 12 described above are realized without impairing the gas supply function.

Moreover, according to the first embodiment, since the uneven shape of the separator 20 is reversed between the front surface and the back surface of the separator 20, the space of the refrigerant flow path increases as the width W ₁ is increased. Therefore, according to the fuel cell 2, various elements such as the gas supply function, the contact area, and the cooling performance can be achieved in a limited space within the separator 20 surface.

  In the fuel cell 2 of the first embodiment described above, the MEA 10 corresponds to the “membrane electrode assembly” in the first invention, and the gas diffusion sheet 12 corresponds to the “gas diffusion sheet” in the first invention. doing. Further, in the fuel cell 2, the separator 20 is the “first separator” in the first invention, the surface of the separator 20 on the front side in FIG. 1 is the “surface” in the first invention, and the separator 20 in FIG. The surface on the back side of the paper corresponds to the “back surface” in the first invention. In the fuel cell 2, the separator 30 corresponds to the “second separator” in the first invention. In the fuel cell 2, the recess 22a corresponds to the “first recess” in the first invention, and the recess 22b corresponds to the “second recess” in the first invention. Further, a space formed by using arrows in FIG. 1 and formed so as to meander in the surface of the separator 20 corresponds to the “space” in the first invention. In the fuel cell 2, of the two through holes 29, one through hole 29 is the “first opening” in the first invention, and the other through hole 29 is the “second opening” in the first invention. Respectively.

In the first embodiment described above, the width W ₁ of the convex portion 24 is the “width of the bottom surface of the convex portion on the surface side” in the second invention, and the width W ₂ of the concave portions 22 a and 22 b is This corresponds to “the width of the first recess and / or the second recess” in the second invention, respectively.

[Modification of Embodiment 1]
(First modification)
In the first embodiment, the gas flow path structure of the fuel cell 2 is different between the anode side and the cathode side. However, the present invention is not limited to this. The gas channel structures on the anode side and the cathode side may both be grooved gas channel structures using separators 20 and 30.

(Second modification)
The fuel cell 2 of Embodiment 1 includes separators 20 and 30 on the anode side and a porous body layer 34 on the cathode side. However, the present invention is not limited to this. The structure may be reversed between the anode side and the cathode side.

  The fuel cell 2 generates power by supplying hydrogen to the anode and air to the cathode. Here, hydrogen gas has higher diffusibility than air. For this reason, the high diffusibility of hydrogen gas can be utilized by arranging the structures of the separators 20 and 30 on the anode. Further, in a fuel cell system in which hydrogen gas supplied to the anode is stored in a tank in a high pressure state, the space in the recess 22a is kept at a higher pressure than the space in the recess 22b during normal operation. . Suppose that a fuel cell in which the structure of the separators 20 and 30 is arranged on the cathode is generated by a system using an air compressor for the air supply system. Then, in such a case, there is a possibility that the power consumption of the air compressor is increased in order to make the recess 22a high pressure to such an extent that the gas flow in the gas diffusion sheet 12 is smoothly generated. From this point of view, the configuration using the separator 20 for the anode as in the fuel cell 2 is advantageous.

  On the other hand, when the separators 20 and 30 are arranged on the cathode side, there are advantages as described below. Along with the power generation reaction of the fuel cell, water is generated at the cathode. As described above, the effect of improving drainage is obtained by the gas flow generated in the surface of the gas diffusion sheet 12 by the configuration of the separator 20. For this reason, if separators 20 and 30 are arranged on the cathode side, the power generation generated water can be discharged smoothly. In particular, in a fuel cell that generates power at a high load (in other words, a large output current), the amount of generated water is also large. Accordingly, a certain level of drainage is required so that the amount of water does not become excessive on the cathode side. Under such a requirement, it is highly advantageous to arrange the separators 20 and 30 on the cathode side.

(Third Modification)
In Embodiment 1, the uneven shape of the separator 20 is designed so that the relationship of width W ₁ > width W ₂ is established. However, the present invention is not limited to this. The width W ₁ ≦ the width W ₂ may be satisfied.

In the first embodiment, has been designed recess 22a and the recess 22b together in the width W _2, the recess 22a and the recess 22b may not necessarily have the same width. That is, when the width of the recess 22a has a width _{W 1b} of the concave portion 22b and _{W 1a} on the cutting plane of FIG. 2 and _3, of the _{W 1a} and _{W 1b,} one is smaller than the width _{W 1,} while the width W may be greater than _1.

The recess 22a, 22b is provided in the separator 20 plane with a constant width W _2, it may be changed partially wide.

(Fourth modification)
In the first embodiment, as shown in FIG. 1, each of the recesses 22a and 22b includes one recess extending from the through hole 26 and three recesses extending from the one recess (hereinafter referred to as “ A comb-like pattern including a “branch portion”. However, the present invention is not limited to this. The recesses 22a and 22b may have a comb-like pattern including three or more branch portions. Conversely, the number of branch portions may be reduced (two or one). When the number of branch portions is one, the pattern of the concave portions 22a and 22b when the separator 20 is viewed in plan is not a comb shape but a key shape.

  Further, several concave portions (also referred to as “sub-branch portions”) may be branched from one branch portion.

  In the first embodiment, the number of branch portions of the recesses 22a and 22b is the same. However, the present invention is not limited to this, and the number of branch portions of the recesses 22a and 22b may be different. For example, the concave portion 22a may be a pattern including four branch portions, and the concave portion 22b may be a pattern including three branch portions, and the concave portions 22a and 22b may be engaged with each other.

  In the first embodiment, the pattern of the recesses 22a and 22b when the separator 20 is viewed in plan is a pattern extending while changing the course to a right angle within the surface of the separator 20. However, the present invention is not limited to this. It may be a pattern extending while changing the course to an acute angle or an obtuse angle instead of a right angle. Moreover, a curve may be included.

(5th modification)
In the first embodiment, the separator 30 is a flat plate. However, the present invention is not limited to this. Any flat plate may be used as long as it forms a meandering space on the back side of the separator 20 in contact with the concave portions 22a and 22b of the separator 20.

  In Embodiment 1, the separators 20 and 30 are made of metal, but the present invention is not limited to this. The separators 20 and 30 may be manufactured using a conductive material as appropriate.

  In the first embodiment, apart from the first idea that the gas flow path and the refrigerant flow path in the separator surface are compatible, there is also a second idea that the gas flow path structures on the anode side and the cathode side are different. include. Specifically, in Embodiment 1, the gas channel structure on one side of the anode side and the cathode side is a groove type gas channel structure, and the gas channel structure on the other side is the porous body layer. The idea of using a gas flow path structure to be used is included. Only such a second idea may be used individually to constitute a fuel cell.

The above second idea is, for example,
"Membrane electrode assembly with electrode catalyst layers on both sides of the electrolyte membrane,
A first gas diffusion sheet overlaid on one surface of the membrane electrode assembly; a second gas diffusion sheet overlaid on the other surface of the membrane electrode assembly;
A first gas supply that is superimposed on the first gas diffusion sheet and has a recess on a surface facing the gas diffusion sheet, the recess being in contact with the first gas diffusion sheet, and the recess being used as a reaction gas flow path. Members,
A second gas supply member that includes a porous body layer that overlaps the second gas diffusion sheet and contacts the second gas diffusion sheet, and a gas supply path that overlaps the porous body layer and supplies the porous body layer When,
Fuel cell with
Offered as.

It is a top view which shows the structure of the fuel cell of Embodiment 1 of this invention. It is a figure which shows the cross section at the time of cut | disconnecting the fuel cell of Embodiment 1 according to the AA arrow line of FIG. It is a figure which decomposes | disassembles and shows the laminated structure of the fuel cell of Embodiment 1 shown in FIG.

Explanation of symbols

2 Fuel Cell 12 Gas Diffusion Sheet 14 Gas Diffusion Sheet 20, 30 Separator 22a, 22b Concave 24 Convex 26, 28, 29 Through Hole 34 Porous Body Layer

Claims (2)

A membrane electrode assembly having electrode catalyst layers on both sides of the electrolyte membrane;
A first gas diffusion sheet overlaid on the anode surface of the membrane electrode assembly; a second gas diffusion sheet overlaid on the cathode surface of the membrane electrode assembly;
An uneven shape that is superimposed on the first gas diffusion sheet, has a surface facing the first gas diffusion sheet side, and a back surface opposite to the surface, and the shape is reversed between the surface and the back surface. A first gas supply comprising: a first separator having a concave portion on the surface side used as a reaction gas flow path; and a second separator stacked on the back surface of the first separator. Members,
A second gas supply member provided with a porous body layer that is stacked on the second gas diffusion sheet and is in contact with the second gas diffusion sheet;
With
The concave-convex shape of the first separator is concave on the surface side, and a pattern when the first separator is viewed in plan is a comb-shaped first concave portion, and the first concave portion is concave on the front surface side. And a second recess that is spaced apart and has a comb shape in which the pattern of the first separator in plan view meshes with the first recess,
The second separator is in contact with the convex portion facing the first and second concave portions on the back side of the first separator, thereby forming a space between the first separator and
The first and second separators in a stacked state form a first opening that opens the space to the outside, and a second opening that opens the space to the outside at a position different from the first opening ,
Each of the first concave portion and the second concave portion includes a plurality of main branch portions branched in the comb shape, and a sub branch portion that is a plurality of concave portions further branched from the main branch portion,
Each of the end portions of the sub-branch portion terminates in a region where the first separator and the membrane electrode assembly overlap each other . The fuel cell according to claim 1, wherein
When the first separator is cut in a direction intersecting with the direction in which the first and second recesses mesh with each other in the power generation region of the fuel cell, the uneven shape of the first separator A fuel cell characterized in that it includes a portion in which the width of the bottom surface is made larger than the width of the first recess and / or the second recess.

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