JP2009252442A - Fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell enabled to have enough moisture drainage in a circulation channel of reaction gas. <P>SOLUTION: A first diffusion layer material constituting a fuel electrode diffusion layer in a unit cell 50a provided at an upstream side of a fuel gas supply manifold 64 in the vicinity of a fuel gas supply port 46 is to have a higher compression rate than a second diffusion layer material constituting a fuel electrode diffusion layer in a unit cell 50b provided at a downstream side of a fuel gas supply manifold 64 separated from the fuel gas supply port 46. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a fuel cell.

  An outline of a configuration of a general unit cell (also referred to as a fuel cell unit cell) corresponding to the minimum unit of the fuel cell, in particular, a main part including an electrode portion will be described. As illustrated in FIG. 4, the oxidation electrode catalyst layer 12 (also referred to as an oxidation electrode or a cathode catalyst layer) and the fuel electrode catalyst layer 14 (also referred to as a fuel electrode or an anode catalyst layer) face each other with the electrolyte membrane 10 interposed therebetween. A membrane electrode assembly (MEA) 30 provided as described above is configured. An oxidation electrode diffusion layer 116 is provided outside the oxidation electrode catalyst layer 12, and a fuel electrode diffusion layer 118 is provided outside the fuel electrode catalyst layer 14. Further, on the outer side of the oxidation electrode diffusion layer 116, an oxidation electrode side separator 26 in which the oxidizing gas flow channel groove 20 and the cell refrigerant flow channel groove 22 are formed on both surfaces thereof is provided on the outer side of the fuel electrode diffusion layer 18. A fuel electrode side separator 28 having a fuel gas channel groove 24 and a cell refrigerant channel groove 22 formed on both sides is provided, respectively, and these are integrated by, for example, adhesion or pressure bonding, so that the single cell 150 is formed. It is formed.

  By stacking a plurality of the obtained single cells 150, it is possible to obtain desired power generation performance. As illustrated in FIG. 5, the stacked ends of the stacked single cells 150 are sandwiched between current collector plates 52 and 54, respectively, and are further sandwiched between insulating plates 56 and 58 and end plates 60 and 62 in order. From, for example, the whole is pressed and held in the stacking direction by a method such as fastening with a bolt or the like (not shown), and the fuel cell 500 is configured.

  In general, the fuel cell has an oxidation gas such as oxygen gas or air in the oxidation electrode catalyst layer 12 shown in FIG. 4, a fuel gas such as hydrogen gas or reformed gas in the fuel electrode catalyst layer 14, and the reaction gases shown in FIG. Electric power is supplied from the supply manifold 164 via the oxidizing gas channel 132 / fuel gas channel 134 shown in FIG. 4 and independently. In general, such a fuel cell generates heat associated with a chemical reaction during power generation. However, in order to maintain stable power generation, it is necessary to control the temperature to be within a predetermined temperature range of, for example, about 60 ° C to 100 ° C. Therefore, a cooling medium (refrigerant) such as water or ethylene glycol is circulated through the cell refrigerant channel 36 provided in each single cell to prevent overheating of the fuel cell. Thus, a chemical reaction occurs in the electrode portion including the fuel electrode and the oxidation electrode, and charges are generated to function as a battery. “Reactive gas” is a general term for fuel gas and / or oxidizing gas.

  In general, in order for a fuel cell to generate electric power satisfactorily, a predetermined amount of water (water content) is maintained with respect to the electrolyte membrane 10 in which, for example, a fluorine-based ion exchange resin such as perfluoro-based or perfluorosulfonic acid is used. Thus, it is preferable to exhibit the function as a proton permeable membrane. In order to prevent so-called dry-up due to insufficient water content of the electrolyte membrane 10, for example, either or both of the reactive gases supplied into the fuel cell are humidified to adjust the moisture of the electrolyte membrane 10.

  On the other hand, if the amount of moisture supplied to the fuel cell exceeds a predetermined amount, the moisture in the gas may be condensed in the gas flow path to generate liquid water (liquid water) (this is referred to as condensed water). ). If this condensed water blocks the gas flow path and the diffusion layer, a so-called flooding phenomenon occurs in which the supply of the source gas necessary for the reaction, that is, the reaction gas, to the catalyst layer becomes insufficient. Not only is the efficiency lowered, but the operating state becomes unstable, and in some cases, the system may be stopped.

  For example, in the gas flow path on the fuel electrode side, that is, the gas flow path in which the fuel gas flows, the flow rate of the fuel gas is generally the gas flow path on the oxidation electrode side, that is, the gas flow in which the oxidation gas flows. Less than the amount of oxidant gas flowing through the road. In addition, with the consumption of hydrogen at the fuel electrode, the flow rate of the fuel gas (off gas) not only gradually decreases from the upstream side to the downstream side of the fuel gas flow path of each single cell, but also in the flow path. The gas flow rate also gradually decreases due to the pressure loss. For this reason, depending on the number of stacked cell stacks and the shape and length of the fuel gas flow path, it may not be sufficient to discharge moisture from the gas flow path only by using the fuel gas flow.

  As described above, a more stable operation of the fuel cell requires a suitable drainage according to the operation conditions and the characteristics of each electrode in the flow of the fuel gas and the oxidizing gas.

  In Patent Document 1, the pressure loss value between at least two single cells is made different by changing the cross-sectional area or the number of gas flow channel grooves on the separator surface, and from the gas supply side among the stacked single cells. A technique for reducing the pressure loss of distant cells is described.

  Patent Document 2 describes a method for producing a diffusion layer obtained by accumulating sheets produced by a papermaking method using carbon short fibers having conductivity.

  In Patent Document 3, among the stacked single cells, the pressure loss is reduced by increasing the cross-sectional area of the gas flow channel groove formed in the separator in the cell far from the gas supply side or shortening the length of the gas flow channel. It describes the technology to reduce.

JP 2005-56671 A JP 2004-273392 A JP 2004-179061 A

  The present invention provides a fuel cell that can have a sufficient water discharging property in a reaction gas flow path.

  The configuration of the present invention is as follows.

  (1) A plurality of unit cells each including a membrane electrode assembly including an electrolyte membrane and a pair of catalyst layers facing each other with the electrolyte membrane interposed therebetween, and a pair of diffusion layers facing each other with the membrane electrode assembly interposed therebetween And a reaction gas supply port for supplying a reaction gas into the cell stack, the reaction gas supply manifold penetrating the cell stack, and the reaction supplied from the reaction gas supply manifold. A reaction gas flow path for distributing gas to each of the single cells and flowing through the catalyst layer; and a separator facing the diffusion layer via the reaction gas flow path, the reaction gas supply port The first diffusion layer material constituting the diffusion layer in the single cell provided on the upstream side of the reaction gas supply manifold is spaced apart from the reaction gas supply port. It has a higher compression ratio than the second diffusion layer material constituting the diffusion layer in the unit cell provided on the downstream side of the response gas supply manifold, a fuel cell.

  (2) In the fuel cell according to the above (1), the reaction gas channel groove formed on the surface of the first separator facing the diffusion layer made of the first diffusion layer material has the second diffusion. A fuel cell having the same shape as a reaction gas channel groove formed on a surface of a second separator facing a diffusion layer made of a layer material.

  (3) In the fuel cell according to the above (1) or (2), the first diffusion layer material allows a dispersion liquid containing conductive fibers to permeate the mesh member for papermaking, and the conductive material passes through the mesh member. A fuel cell, which is a paper-like substrate formed including a paper-making method for depositing conductive fibers.

  (4) In the fuel cell according to any one of (1) to (3), the second diffusion layer material is carbon paper obtained by carbonizing and graphitizing a substrate formed by a papermaking method. ,Fuel cell.

  (5) In the fuel cell according to any one of (1) to (4), the pair of electrodes includes an oxidizing electrode that uses an oxidizing gas as the reactive gas, and a fuel that uses a fuel gas as the reactive gas. A fuel cell, wherein the first diffusion layer material and the second diffusion layer material are diffusion layer materials constituting the fuel electrode diffusion layer.

  According to the present invention, it is possible to have a sufficient water discharging property in the reaction gas flow path.

  Embodiments of the present invention will be described with reference to the drawings. In addition, in each drawing demonstrated below, the same code | symbol is attached | subjected about the thing similar to the structure shown in FIG.4, 5, and the description is abbreviate | omitted.

  FIG. 1 is a schematic diagram showing an outline of a configuration of a fuel cell according to an embodiment of the present invention. In the fuel cell 100 shown in FIG. 1, a single cell 50 a is located near the fuel gas supply port 46 and upstream of the fuel gas supply manifold 64, and is separated from the fuel gas supply port 46. A single cell 50b is provided on each downstream side. The single cells 50a and 50b shown in FIG. 1 will be further described with reference to FIG.

  FIG. 2 is an enlarged view showing an outline of the configuration of the main parts of the single cells 50a and 50b shown in FIG. A unit cell 50a shown in FIG. 2A is provided with a fuel electrode diffusion layer 18, and a fuel gas channel 34 is formed between the fuel gas channel groove 24 on the surface of the fuel electrode side separator 28. Yes. On the other hand, the unit cell 50b shown in FIG. 2B is provided with a fuel electrode diffusion layer 38, and a fuel gas channel 44 is formed between the surface of the fuel electrode side separator 28 and the fuel gas channel groove 24. Has been. That is, the single cells 50a and 50b shown in FIG. 2 have substantially the same configuration as the single cells 150 (150a and 150b) shown in FIGS. 4 and 5 except for the configuration of the anode diffusion layer.

  FIG. 3 is an enlarged view of each of the single cells 50a and 50b shown in FIG. 2, and further illustrates the shape of the fuel gas flow path formed between the fuel electrode diffusion layer and the fuel gas flow path groove 24. FIG. . In FIG. 3, the diffusion layer material (first diffusion layer material) 18a (FIG. 3A) constituting the anode diffusion layer 18 (single cell 50a) constitutes the anode diffusion layer 38 (single cell 50b). It has a higher compression ratio than the diffusion layer material (second diffusion layer material) 38a (FIG. 3B). Therefore, as shown in FIG. 3A, when the diffusion layer material 18a having a high compressibility is applied and the diffusion layer material 38a and the fuel electrode side separator 28 are pressed and sandwiched at a predetermined pressure, the fuel While the degree of protrusion (also referred to as “sagging”) 40 of the pole diffusion layer 18 into the fuel gas flow channel groove 24 increases and the cross-sectional area of the fuel gas flow channel 34 decreases, in FIG. Even when the layer material 38a and the fuel electrode side separator 28 are pressed and clamped at the same pressure as in FIG. 3A, the sag 42 of the fuel electrode diffusion layer 38 is slight.

  As described above, when the diffusion layer materials having different compression ratios are used in combination, a difference occurs in the degree of sagging of the fuel electrode diffusion layer (material) based on the difference in the compression ratios. For this reason, for example, even when using a fuel electrode side separator in which fuel gas flow channel grooves of the same shape are used, in each single cell, based on the difference in compressibility of the diffusion layer material used in combination with this separator A difference occurs in the flow volume of the fuel gas flow path. In fuel gas passages with different passage volumes, the degree of pressure loss with respect to the fuel gas flowing through the inside differs, so a fuel cell is fabricated by appropriately combining the single cells using diffusion layer materials having different compression ratios. This can contribute to the control of the flow rate of the fuel gas on the fuel electrode side.

  That is, as shown in FIG. 1, by applying a diffusion layer material having a high compressibility to the upstream side of the fuel gas supply manifold 64, the fuel gas for the single cell 50a disposed on the upstream side of the fuel gas supply manifold 64. On the other hand, on the downstream side of the fuel gas supply manifold 64, the fuel for the single cell 50 b disposed downstream of the fuel gas supply manifold 64 is applied by applying a diffusion layer material having a lower compression rate than that. Gas inflow can be increased. For this reason, even in the single cell downstream of the fuel gas supply manifold 64, which generally tends to decrease the amount of gas flow, it is possible to appropriately discharge moisture from the flowing fuel gas.

  In the embodiment of the present invention, the number of single cells 50a provided with a fuel gas diffusion layer using a diffusion layer material having a high compression ratio, which is arranged on the upstream side of the fuel gas supply manifold 64 shown in FIG. 1, is limited to one. The number of single cells in the cell stack, the shape of the fuel gas flow path, and the like can be determined as appropriate. Similarly, the number of the single cells 50b provided with the fuel gas diffusion layer using the diffusion layer material having a relatively low compressibility disposed on the downstream side of the fuel gas supply manifold 64 is not limited to one, and may be plural. It can be appropriately determined according to the number of single cells stacked in the cell stack, the shape of the fuel gas flow path, and the like.

  Further, as another embodiment of the present invention, a diffusion layer material (shown in FIG. 2) constituting each fuel electrode diffusion layer provided between the single cell 50a and the single cell 50b shown in FIG. It is also preferable to stack the single cells 50 each including a fuel electrode diffusion layer made of a diffusion layer material having a compression ratio intermediate between the diffusion layer materials 18a and 38a). According to the present embodiment, it becomes possible to further subdivide the control of the pressure loss in the fuel gas flow path according to the stacking portion of the single cells. Therefore, in the fuel cell in which a large number of single cells are stacked. Is preferred.

  In the embodiment of the present invention, the “compressibility” of the diffusion layer material is, for example, based on the thickness of the prepared diffusion layer material in the stacking direction when the diffusion layer material is stacked as a single cell. The diffusion layer is compressed when a constant load or pressure is applied to the entire surface (corresponding to the load or surface pressure when a single cell or a cell stack is laminated. For example, it can be set to about 1 MPa to 2 MPa). It can be expressed as a measure of the thickness of the material. More specifically, the compression rate can be measured in accordance with JIS L1913 6.12. However, the “compressibility” of the diffusion layer material in this specification is not limited as long as the relative comparison between the respective diffusion layer materials is possible, and the absolute value is not so important. The method is not limited to this as long as the degree can be compared.

  In FIG. 1, as a first diffusion layer material having a high compression ratio, which is preferably used for the single cell 50a upstream of the fuel gas supply manifold 64 (in the vicinity of the fuel gas supply port 46), for example, a mesh member for papermaking It is possible to apply a paper-like substrate formed by including a paper-making method in which a dispersion liquid containing conductive fibers is permeated and the conductive fibers are deposited on the mesh member.

  On the other hand, in FIG. 1, as a second diffusion layer material having a compressibility lower than that of the first diffusion layer material used on the downstream side of the fuel gas supply manifold 64, for example, a base material formed by a papermaking method is carbonized. Graphitized carbon paper can be applied.

  In the embodiment of the present invention, the diffusion layer materials 18a and 38a shown in FIG. 3 have been described as the diffusion layer material constituting the fuel electrode diffusion layer, but this can also be applied to the oxidation electrode diffusion layer. For example, the first diffusion layer material 18a having a high compression ratio is compressed on the upstream side (near the oxidation gas supply port) side of the oxidizing gas supply manifold, and the first diffusion layer material 18a is compressed on the downstream side of the oxidizing gas supply manifold. By applying the second diffusion layer material 38a having a low rate, moisture in the oxidizing gas flow channel can be quickly discharged even on the downstream side of the oxidizing gas supply manifold.

  Fuel cells were fabricated by stacking single cells having the same structure except that diffusion layer materials having different compression ratios were used, and the cell voltage stability was compared.

[Preparation of diffusion layer material 1 (paper-like substrate)]
Carbon fiber short fibers (typical size is 13 μm in diameter, 3 mm in length) and pulp are mixed at a mass ratio of 6: 4 and beaten in water to mix the conductive fibers and pulp. A paper slurry was uniformly dispersed. Next, using this papermaking slurry, papermaking processing was performed with a net-like member, and the solid content contained in the papermaking slurry was separated from the liquid component to produce a thin layer sheet having a thickness of about 0.3 mm. Next, a paste was prepared by mixing and dispersing carbon black (Denka Black, manufactured by Denki Kagaku Kogyo) and water repellent (PTFE dispersion D-1, manufactured by Daikin Kogyo Co., Ltd.) at a mass ratio of 5: 2. The sheet surface was coated with a roll coater and impregnated. After drying, it was baked at 380 ° C. for 1 hour, and the pulp contained in the thin layer sheet was lost. This sheet was hot-pressed so that the thickness was uniform in the plane, and a diffusion layer material 1 which was a carbon sheet having a thickness of about 0.3 mm and a density of 7.6 mg / cm ² was obtained.

[Production of diffusion layer material 2 (carbon paper)]
A paste was prepared by mixing and dispersing carbon black (Denka Black, manufactured by Denki Kagaku Kogyo) and a water repellent (PTFE dispersion D-1, manufactured by Daikin Industries) at a mass ratio of 3: 2, and the thickness was about 0. .2 mm carbon paper (TGP-H-060, manufactured by Toray Industries, Inc.) was coated and impregnated by the die coating method. After drying, carbon black (VGCF (trade name), manufactured by Showa Denko) and water repellent (PTFE dispersion D-1, manufactured by Daikin Industries) were mixed and dispersed at a mass ratio of 3: 2 as the second layer. A paste was prepared and applied and impregnated by a die coating method. After drying, baking was performed at 380 ° C. for 1 hour to obtain a diffusion layer material 2 having a thickness of about 0.3 mm and a density of 7.8 mg / cm ² .

[Production of Diffusion Layer Material 3]
A paste was prepared by mixing and dispersing carbon black (Denka Black, manufactured by Denki Kagaku Kogyo) and a water repellent (PTFE dispersion D-1, manufactured by Daikin Industries) at a mass ratio of 3: 2, and the thickness was about 0. A 2 mm carbon paper (TGP-H-060, manufactured by Toray Industries, Inc.) was applied by a doctor blade method and impregnated. After drying, baking was performed at 380 ° C. for 1 hour to obtain a diffusion layer material 3 having a thickness of about 0.3 mm and a density of 6.5 mg / cm ² .

  About the diffusion layer materials 1-3, the degree of the "compression rate" was compared. Specifically, the thickness of each diffusion layer material when the load is not applied is set to 100, and the thickness when pressed at a constant surface pressure (1 MPa, 2 MPa) is measured at n = 10. Averaged. The results are shown in Table 1.

  As shown in Table 1, although the degree of compression varies depending on the degree of surface pressure, it can be seen that the diffusion layer material 1 has the highest compression ratio and the diffusion layer material 2 has the lowest compression ratio. .

[Production of single cell 1]
Using the diffusion layer material 1 described above as the fuel electrode diffusion layer and the diffusion layer material 3 as the oxidation electrode diffusion layer, a single cell 1 having a configuration as shown in FIG. 2 was produced.

[Production of single cell 2]
A single cell 2 having the same configuration as that of the single cell 1 was prepared except that the diffusion layer material 2 was used as the fuel electrode diffusion layer.

[Production of single cell 3]
A single cell 3 having the same configuration as the single cell 1 was produced except that the diffusion layer material 3 was used as the fuel electrode diffusion layer.

  Next, the fuel cell which has a structure as shown in FIG. 1 was produced combining the single cells 1-3.

[Fabrication of fuel cell 1]
In FIG. 1, the single cell 1 is located on the upstream side of the fuel gas supply manifold 64, which is in the vicinity of the fuel gas supply port 46, and the single cell 2 is located on the downstream side of the fuel gas supply manifold 64, which is separated from the fuel gas supply port 46. Were prepared, and a fuel cell 1 in which single cells 3 were stacked in the middle was prepared. The total number of single cells constituting the cell stack was 10 pieces, of which 2 single cells 1 and 2 each. Further, the surface pressure in the single cell stacking direction when the end cells 60 and 62 were fastened was set to 1 MPa.

[Fabrication of fuel cell 2]
A fuel cell 2 having the same configuration as that of the fuel cell 1 was produced except that the single cell 2 was used instead of the single cell 1 and the single cell 1 was used instead of the single cell 2.

[Fabrication of fuel cell 3]
A fuel cell 3 having the same configuration as that of the fuel cell 1 was manufactured except that all the single cells were replaced with the single cell 3.

  In the following description, the single cell on the most upstream side of the fuel gas supply manifold 64 is the cell number 1 in the fuel cells 1 to 3 in which 10 single cells are stacked, and the most downstream side of the fuel gas supply manifold 64. These single cells are also referred to as cell number 10, and single cells arranged in the middle are also referred to as cell numbers 2-9.

[Evaluation of fuel cell performance]
・ Fuel gas utilization rate limit test [Example 1]
When the produced fuel cell 1 is used and pure hydrogen gas is used as the fuel gas, air is used as the oxidizing gas, and the oxidizing gas utilization rate is constant, the fuel gas utilization rate is gradually increased. To what extent, stable battery performance can be demonstrated. The measurement conditions are as follows: current density = 0.078 A / cm ² , oxidizing gas utilization rate = 50%, dew point temperature (anode / cathode) = 60 ° C./65° C., (cooling water temperature) to cell stack Inlet temperature = 71 ° C., outlet temperature from cell stack = 72 ° C. The measurement is carried out continuously for 10 minutes at each fuel gas utilization rate, the average cell voltage in the single cells of cell numbers 1, 5, and 10 at that time, and the maximum value of 3σ when the standard deviation is σ ( 3σ _max ) were calculated respectively. Table 2 shows the results.

  According to Table 2, it can be seen that stable operation is performed up to a fuel gas utilization rate of 80%.

[Comparative Example 1]
The same test as in Example 1 was performed except that the fuel cell 2 was used. Table 3 shows the results.

  As shown in Table 3, stable operation could not be performed at a fuel gas utilization rate of 80%.

[Comparative Example 2]
The same test as in Example 1 was performed except that the fuel cell 3 was used. The cell voltage and 3σ _max are measured only for cell number 5, and the results are shown in Table 4.

  As shown in Table 4, when the fuel gas utilization rate was 80%, the cell voltage varied greatly and stable operation could not be performed.

・ Oxidizing gas utilization rate limit test [Example 2]
When the fuel cell 1 is used, pure hydrogen gas is used as the fuel gas, air is used as the oxidizing gas, and air is used, and the fuel gas usage rate is constant, the oxidizing gas usage rate is increased step by step. It was evaluated whether stable battery performance could be exhibited to the extent. Measurement conditions are as follows: current density = 0.078 A / cm ² , fuel gas utilization rate = 70%, dew point temperature (anode / cathode) = 60 ° C./65° C., (cooling water temperature) to cell stack Inlet temperature = 71 ° C., outlet temperature from cell stack = 72 ° C. In addition, the measurement is carried out continuously for 10 minutes at each oxidizing gas utilization rate, the average cell voltage in the single cells of the cell numbers 1, 5 and 10 at that time, and the maximum value of 3σ when the standard deviation is σ ( 3σ _max ) were calculated respectively. Table 5 shows the results.

  According to Table 5, it turns out that the driving | operation stable to the utilization factor of 65% of oxidizing gas is performed.

[Comparative Example 3]
The same test as in Example 2 was performed except that the fuel cell 2 was used. Table 6 shows the results.

  As shown in Table 6, a stable operation could not be performed at an oxidation gas utilization rate of 55%.

[Comparative Example 4]
The same test as in Example 2 was performed except that the fuel cell 3 was used. The cell voltage and 3σ _max are measured only for cell number 5, and the results are shown in Table 7.

  As shown in Table 7, stable operation could not be performed at a fuel gas utilization rate of 65%.

  The present invention can be preferably used particularly in a fuel cell including a cell stack formed by stacking a plurality of single cells.

It is a schematic diagram which shows the outline of a structure of a fuel cell. It is an enlarged view which shows the outline of the structure about the principal part of single cell 50a, 50b shown in FIG. It is a figure explaining the shape of the fuel gas flow path formed between a fuel electrode diffusion layer and a fuel gas flow path groove. It is the schematic shown about the structure of the principal part of a single cell. It is a schematic diagram which shows the outline of a structure of the conventional fuel cell.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Electrolyte membrane, 12 Oxidation electrode catalyst layer, 14 Fuel electrode catalyst layer, 18, 38, 118 Fuel electrode diffusion layer, 18a, 38a Diffusion layer material, 20 Oxidation gas channel groove, 22 Cell refrigerant channel groove, 24 Fuel gas Channel groove, 26 Oxide electrode side separator, 28 Fuel electrode side separator, 30 Membrane electrode assembly (MEA), 34, 44, 134 Fuel gas channel, 36 Cell refrigerant channel, 40, 42 Sag, 46 Fuel gas Supply port, 48 Fuel gas discharge port, 50, 50a, 50b, 150, 150a, 150b Single cell, 52, 54 Current collector plate, 56, 58 Insulating plate, 60, 62 End plate, 64 Fuel gas supply manifold, 68 Fuel Gas exhaust manifold, 100,500 Fuel cell, 116 Oxidizing electrode diffusion layer, 132 Oxidizing gas flow path, 164 Reaction gas supply manifold, 16 8 Reaction gas discharge manifold.

Claims (5)

A plurality of single cells each including an electrolyte membrane and a membrane electrode assembly including a pair of catalyst layers facing each other with the electrolyte membrane interposed therebetween and a pair of diffusion layers facing each other with the membrane electrode assembly interposed therebetween are stacked. Cell stack,
A reaction gas supply port for supplying a reaction gas into the cell stack, and a reaction gas supply manifold penetrating the cell stack;
A reaction gas flow path for distributing the reaction gas supplied from the reaction gas supply manifold to each of the single cells and circulating the reaction gas to the catalyst layer;
A separator facing the diffusion layer via the reaction gas flow path;
With
The first diffusion layer material constituting the diffusion layer in the single cell provided in the vicinity of the reaction gas supply port and upstream of the reaction gas supply manifold is separated from the reaction gas supply port, A fuel cell having a higher compressibility than a second diffusion layer material constituting a diffusion layer in a single cell provided downstream of a reaction gas supply manifold. The fuel cell according to claim 1, wherein
The reaction gas flow channel groove formed on the surface of the first separator facing the diffusion layer made of the first diffusion layer material has the second separator facing the diffusion layer made of the second diffusion layer material. A fuel cell having the same shape as a reaction gas channel groove formed on a surface thereof. The fuel cell according to claim 1 or 2,
The first diffusion layer material is a paper-like base material formed by including a paper-making method in which a dispersion liquid containing conductive fibers is allowed to pass through a paper mesh member and the conductive fibers are deposited on the mesh member. The fuel cell characterized by the above-mentioned. The fuel cell according to any one of claims 1 to 3,
The fuel cell, wherein the second diffusion layer material is carbon paper obtained by carbonizing and graphitizing a base material formed by a papermaking method. The fuel cell according to any one of claims 1 to 4, wherein
The pair of diffusion layers includes an oxidation electrode diffusion layer using an oxidation gas as the reaction gas and a fuel electrode diffusion layer using a fuel gas as the reaction gas,
The fuel cell, wherein the first diffusion layer material and the second diffusion layer material are diffusion layer materials constituting a fuel electrode diffusion layer.

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