Fuel cell single body, fuel cell, and method for manufacturing fuel cell single body

Abstract

The present disclosure provides a fuel cell single body, a fuel cell, and a manufacturing method of a fuel cell single body. The fuel cell single body includes: a first separator, a first gas diffusion layer, a first catalyst layer, a polymer electrolyte membrane, a second catalyst layer, a second gas diffusion layer, and a second separator, which are sequentially stacked along a stacking direction; a first gas flow path portion provided between the first separator and the first gas diffusion layer; and a second gas flow path portion provided between the first separator and the first gas diffusion layer and adjacent to the first gas flow path portion in a direction intersecting the stacking direction, the flow path area of the second gas flow path portion being larger than that of the first gas flow path portion as viewed in plan along the stacking direction. The first gas diffusion layer includes: a first low elastic modulus portion facing the first gas flow path portion; and a first high elastic modulus portion facing the second gas flow path portion and having a higher compressive elastic modulus than the first low elastic modulus portion in the stacking direction.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a fuel cell single body, a fuel cell, and a manufacturing method of a fuel cell single body. BACKGROUND

[0002] As an example of a fuel cell, there is a polymer electrolyte fuel cell. The polymer electrolyte fuel cell synthesizes water by exposing one face of a hydrogen ion-conducting polymer electrolyte membrane to a fuel gas such as hydrogen and exposing the other face to oxygen, and thereby extracting the reaction energy generated at that time in the form of electricity through a chemical reaction via the electrolyte membrane.

[0003] A single cell of the polymer electrolyte fuel cell has a membrane electrode assembly (hereinafter referred to as MEA) and a pair of electrically conductive separators disposed on both faces of the MEA.

[0004] The MEA has a hydrogen ion-conducting polymer electrolyte membrane and a pair of electrode layers sandwiching the electrolyte membrane. The pair of electrode layers is formed on both faces of the polymer electrolyte membrane and has a catalyst layer mainly composed of carbon powder on which a platinum group catalyst is supported, and a gas diffusion layer formed on the catalyst layer and having electron conduction paths between the catalyst layer and the separators, gas permeability, and hydrophobicity.

[0005] The gas diffusion layer functions to uniformly supply the gas supplied from the separators to the catalyst layer, and thus needs to have good gas permeability and gas diffusivity. In addition, the gas diffusion layer needs to have excellent electrical conductivity as an electrically conductive path of electrons between the catalyst layer and the separators. On the surface of the separator that is in contact with the gas diffusion layer, a gas flow path having a predetermined pattern is formed in order to remove the supplied gas and excess moisture.

[0006] In Patent Literature 1, a manufacturing method of a gas diffusion layer for a fuel cell is disclosed. In Patent Literature 1, by increasing the hardness of the gas diffusion layer, the problem that in the case where the gas diffusion layer is made of a carbon cloth or a carbon felt that is high in flexibility but insufficient in hardness, the gas diffusion layer is hung down to the gas flow path of the separator, the deviation of the pressure loss in the gas flow path increases, and flooding easily occurs, is solved.

[0007] In Patent Literature 2, a gas diffusion layer for a fuel cell is disclosed, which contains a fluororesin and carbon particles, and the compressive elastic modulus of the gas diffusion layer in the thickness direction is 15 N / mm 2 The above. According to the gas diffusion layer for a fuel cell of Patent Literature 2, even in the case where a large pressure is applied in the thickness direction, the deformation of the gas diffusion layer caused by the unevenness of the surface of the separator or the like can be suppressed.

[0008] In Patent Literature 3, a separator in which the shape of the flow path and the ribs is changed within the electrode is proposed.

[0009] Prior Art Documents

[0010] Patent Documents

[0011] Patent Document 1: Japanese Patent No. 4824298

[0012] Patent Document 2: Japanese Laid-Open Patent Publication No. 2007-242444

[0013] Patent Document 3: Japanese Patent No. 4469415 SUMMARY

[0014] A fuel cell unit according to one embodiment of the present disclosure includes: a first separator, a first gas diffusion layer, a first catalyst layer, a polymer electrolyte membrane, a second catalyst layer, a second gas diffusion layer, and a second separator, which are sequentially stacked in a stacking direction; a first gas flow path portion provided between the first separator and the first gas diffusion layer; and a second gas flow path portion provided between the first separator and the first gas diffusion layer and provided adjacent to the first gas flow path portion in a direction intersecting the stacking direction, the flow path area of which, as viewed in plan, is larger than that of the first gas flow path portion. The first gas diffusion layer has: a first low elastic modulus portion facing the first gas flow path portion; and a first high elastic modulus portion facing the second gas flow path portion and having a higher compressive elastic modulus than the first low elastic modulus portion in the stacking direction. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 is a schematic exploded perspective view of a fuel cell including the fuel cell unit according to the first embodiment of the present disclosure.

[0016] Figure 2 is an exploded perspective view of the fuel cell unit according to Figure 1

[0017] Figure 3 is a partial cross-sectional view along the III-III line of Figure 1

[0018] Figure 4 is a cross-sectional view along the III-III line of the fuel cell unit according to the second embodiment of the present disclosure. Figure 1

[0019] Figure 5 is a flowchart showing a manufacturing method of the fuel cell unit according to Figure 1

[0020] Figure 6 is a first view for explaining Step 3 of the flowchart of Figure 5

[0021] is a second view for explaining Step 3 of the flowchart of​​​​Figure 7 It is used for explanation Figure 5 The second diagram of step 3 in the flowchart.

[0022] Figure 8 It is used for explanation Figure 5 The third diagram of step 3 in the flowchart.

[0023] Figure 9 It is used for explanation Figure 5 The fourth figure in step 3 of the flowchart.

[0024] Figure 10 It is used for explanation Figure 5 The fifth figure in step 3 of the flowchart.

[0025] Figure 11 It is used for explanation Figure 5 The sixth figure in step 3 of the flowchart.

[0026] Figure 12 This is a graph showing the results of the evaluation test of the gas diffusion layer.

[0027] Symbol Explanation

[0028] 100 fuel cells

[0029] 1. Polymer electrolyte membrane

[0030] 2a Anode catalyst layer

[0031] 2b Cathode catalyst layer

[0032] 3a Anode-side gas diffusion layer

[0033] 3b Cathode-side gas diffusion layer

[0034] 4a Anode-side spacer

[0035] 4b Cathode-side spacer

[0036] 5 First gas flow path section

[0037] 5a Anode Gas Flow Path

[0038] 5b Cathode gas flow path

[0039] 5' Low elastic modulus section

[0040] 6 Second gas flow path section

[0041] 6' High elastic modulus section

[0042] 7 Cooling medium flow path

[0043] 8 Gas supply port

[0044] 8a Anode gas supply port

[0045] 8b Cathode gas supply port

[0046] 8c Cooling medium gas supply hole

[0047] 9 Resin Sheets

[0048] 10. Fuel Cell Unit

[0049] 11. Current collector

[0050] 12 Insulation Board

[0051] 13 end plates

[0052] 15 Third Gas Flow Path Section

[0053] 16 Fourth Gas Flow Path Section

[0054] 20 MEA

[0055] 30 Gas diffusion layer

[0056] 31 First rolled sheet

[0057] 32 Second rolled sheet

[0058] 41, 51 Spacer Main Body

[0059] Surfaces 41a, 51a, and 51b

[0060] 42 First slot

[0061] 43 First Rib

[0062] 52 Second slot

[0063] 53 Third slot

[0064] 54 Second Rib Detailed Implementation

[0065] As described above, Patent Documents 1 and 2 disclose gas diffusion layers for fuel cells. Patent Document 3 proposes a spacer in which the shape of the flow path and ribs varies within the electrode.

[0066] Depending on the shape of the spacer, as in Patent Document 3, the area of ​​the flow path viewed from above (hereinafter referred to as top view) along the thickness direction of the gas diffusion layer is sometimes locally smaller than the area of ​​the ribs viewed from above, either inside or outside the electrode surface. When the gas diffusion layers of Patent Documents 1 and 2 are applied to spacers of this shape, in areas with a smaller shape where the area of ​​the ribs viewed from above is greater than the gas flow path, the space between the gas diffusion layer and the spacer sometimes cannot adequately suppress deformation of the gas diffusion layer, and the water discharge capacity of the gas diffusion layer cannot be adequately improved. Furthermore, in areas with a smaller shape where the area of ​​the ribs viewed from above is greater than the gas flow path, the spacer cannot adequately reduce pressure loss caused by deformation of the gas diffusion layer. In other words, it is difficult to obtain a fuel cell cell that can prevent deformation of the gas diffusion layer, improve the water discharge capacity of the gas diffusion layer, and reduce pressure loss.

[0067] The purpose of this disclosure is to provide a fuel cell cell capable of suppressing deformation of the gas diffusion layer, a fuel cell having the fuel cell cell, and a method for manufacturing the fuel cell cell.

[0068] One embodiment of the fuel cell cell disclosed herein includes: a first spacer, a first gas diffusion layer, a first catalyst layer, a polymer electrolyte membrane, a second catalyst layer, a second gas diffusion layer, and a second spacer, sequentially stacked along a stacking direction; a first gas flow path disposed between the first spacer and the first gas diffusion layer; and a second gas flow path disposed between the first spacer and the first gas diffusion layer, and adjacent to the first gas flow path in a direction intersecting the stacking direction, wherein the flow path area viewed from above along the stacking direction is larger than that of the first gas flow path. The first gas diffusion layer includes: a first low elastic modulus portion opposite to the first gas flow path; and a first high elastic modulus portion opposite to the second gas flow path, having a higher compressive elastic modulus than the first low elastic modulus portion in the stacking direction.

[0069] One aspect of this disclosure relates to a fuel cell comprising: the fuel cell cell; and a pair of current collectors, respectively disposed on both sides of the stacking direction of the fuel cell cell.

[0070] A first method for manufacturing a fuel cell cell according to one aspect of this disclosure is a method for manufacturing the fuel cell cell, comprising the following steps: Rolling a compound prepared by mixing raw materials of the first low elastic modulus portion to form a first rolled sheet with a shape corresponding to the first low elastic modulus. Rolling a compound prepared by mixing raw materials of the first high elastic modulus portion to form a second rolled sheet with a shape corresponding to the first high elastic modulus. Positioning the first rolled sheet opposite to the first gas flow path portion, and positioning the second rolled sheet opposite to the second gas flow path portion, then rolling the first rolled sheet and the second rolled sheet to form the first gas diffusion layer.

[0071] A second method for manufacturing a fuel cell cell according to one aspect of this disclosure is a method for manufacturing the fuel cell cell, comprising the following steps: rolling a first compound prepared by mixing raw materials to form a first rolled sheet with a shape corresponding to the first gas diffusion layer; rolling a second compound prepared by mixing the raw materials to form a second rolled sheet with a shape corresponding to the first high elastic modulus portion; and forming the first gas diffusion layer by stacking and rolling the first rolled sheet and the second rolled sheet together.

[0072] A third method for manufacturing a fuel cell cell according to one aspect of this disclosure is a method for manufacturing the fuel cell cell, comprising the following steps: Rolling a compound prepared by mixing raw materials of the first low elastic modulus portion to form a first rolled sheet with a shape corresponding to the first low elastic modulus portion. Rolling a compound prepared by mixing raw materials of the first high elastic modulus portion to form a second rolled sheet with a shape corresponding to the first high elastic modulus portion. Positioning the first rolled sheet at a position corresponding to the first gas flow path portion, and positioning the second rolled sheet at a position corresponding to the second gas flow path portion. Then, stacking a resin sheet with a shape corresponding to the first high elastic modulus portion onto the second rolled sheet, thereby forming the first gas diffusion layer by rolling the first rolled sheet, the second rolled sheet, and the resin sheet.

[0073] According to this disclosure, a fuel cell cell capable of suppressing deformation of the gas diffusion layer can be obtained.

[0074] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. Furthermore, in the drawings, the same structural elements are labeled with the same symbols, and descriptions are omitted where appropriate. Moreover, the embodiments are not limited to the present disclosure, but are merely illustrative; appropriate modifications can be made without departing from the spirit of the present disclosure.

[0075] <Fuel Cells>

[0076] like Figure 1As shown, a fuel cell 100 according to one embodiment of the present disclosure includes a fuel cell cell 10 and a current collector plate 11. In this embodiment, as an example, the fuel cell 100 includes a plurality of fuel cell cells 10 stacked in the thickness direction. The current collector plate 11 is respectively disposed on both sides of the stacked fuel cell cells 10 in the stacking direction. An insulating plate 12 and an end plate 13 are respectively disposed on both sides of the current collector plate 11 in the stacking direction of the fuel cell cells 10. Figure 1 In the fuel cell 100, the fuel cell cell 10, current collector 11, insulation plate 12, and end plate 13 are tightly fastened together under a specified load compression state by the current collector plate 11, insulation plate 12, and end plate 13. Alternatively, the fuel cell cell 10 can be a single piece. Furthermore, when multiple fuel cell cells 10 are stacked, a gasket (not shown) may be provided between adjacent fuel cell cells 10.

[0077] The current collector 11 is made of an airtight conductive material such as copper or brass. A current extraction terminal (not shown) is provided on the current collector 11, from which current is extracted during power generation.

[0078] The insulating plate 12 is made of insulating materials such as fluorinated resin and PPS resin. Gas or cooling water inlets and outlets (not shown) can also be provided on the insulating plate 12.

[0079] The end plate 13 is made of a high-rigidity metal material such as steel. The fuel cell cell 10, current collector 11, and insulation plate 12 are secured and held by a pressurizing mechanism (not shown) across the end plate 13 with a specified load.

[0080] <Fuel Cell Unit>

[0081] (First Implementation)

[0082] Figure 2 This is an exploded perspective view of fuel cell cell 10. Figure 3 It is along Figure 1 A cross-sectional view along line III-III.

[0083] like Figure 2As shown, the fuel cell unit 10 has a membrane electrode assembly (hereinafter referred to as MEA) 20 and a pair of spacers (hereinafter referred to as anode-side spacers 4a and cathode-side spacers 4b) that clamp the MEA 20 from both sides in its film thickness direction. The MEA 20 has a polymer electrolyte membrane 1 and catalyst layers 2a and 2b (hereinafter referred to as anode catalyst layer 2a and cathode catalyst layer 2b) and gas diffusion layers 3a and 3b (hereinafter referred to as anode-side gas diffusion layer 3a and cathode-side gas diffusion layer 3b) respectively disposed on both sides of the polymer electrolyte membrane 1 in its film thickness direction. That is, the fuel cell unit 10 has a structure in which the anode-side spacer 4a (an example of a first spacer), the anode-side gas diffusion layer 3a (an example of a first gas diffusion layer), the anode catalyst layer 2a (an example of a first catalyst layer), the polymer electrolyte membrane 1, the cathode catalyst layer 2b (an example of a second catalyst layer), the cathode-side gas diffusion layer 3b (an example of a second gas diffusion layer), and the cathode-side gas spacer 4b (an example of a second spacer) are stacked in this order. Alternatively, the cathode-side spacer 4b can be designated as the first spacer, the cathode-side gas diffusion layer 3b as the first gas diffusion layer, the cathode catalyst layer 2b as the first catalyst layer, the anode catalyst layer 2a as the second catalyst layer, the anode-side gas diffusion layer 3a as the second diffusion layer, and the anode-side gas spacer 4a as the second spacer.

[0084] The bonding pair of the anode catalyst layer 2a, the polymer electrolyte membrane 1, and the cathode catalyst layer 2b is called the Catalyst Coated Membrance (CCM). The polymer electrolyte membrane 1 has the same surface area as the anode catalyst layer 2a and the cathode catalyst layer 2b, or a larger surface area than the anode catalyst layer 2a and the cathode catalyst layer 2b.

[0085] Anode-side spacer 4a Figure 2 as well as Figure 3As shown, as an example, a spacer body 41 has a plate-shaped structure. On the surface 41a of the spacer body 41 opposite the anode-side gas diffusion layer 3a, a plurality of first grooves 42 constituting the anode gas flow path 5a are provided, and gas supply holes 8 are configured to sandwich the plurality of first grooves 42. Each gas supply hole 8 penetrates the anode-side spacer 4a in its thickness direction. Furthermore, as an example, the cathode-side spacer 4b has a plate-shaped spacer body 51. On the surface 51a of the spacer body 51 opposite the cathode-side gas diffusion layer 3b, a plurality of second grooves 52 constituting the cathode gas flow path 5b are provided, and gas supply holes 8 are configured to sandwich the plurality of second grooves 52. Each gas supply hole 8 penetrates the cathode-side spacer 4b in its thickness direction. On the surface 51b of the spacer body 51 opposite to surface 51a in the thickness direction, a plurality of third grooves 53 constituting a cooling medium flow path are provided. In this embodiment, the anode gas flow path 5a is composed of a first gas flow path section 5 and a second gas flow path section 6 disposed between the first gas flow path section 5 and the gas supply hole 8. Furthermore, the cathode gas flow path 5b is composed of a third gas flow path section 15 and a fourth gas flow path section 16 disposed between the third gas flow path section 15 and the gas supply hole 8.

[0086] The first gas flow path 5 and the second gas flow path 6 each have a flow path area when viewed from above along the stacking direction of the MEA20. The flow path area of ​​the second gas flow path 6 is larger than that of the first gas flow path 5.

[0087] The third gas flow path 15 and the fourth gas flow path 16 each have a flow path area when viewed from above along the stacking direction of the MEA20. The flow path area of ​​the fourth gas flow path 16 is larger than that of the third gas flow path 15.

[0088] Additionally, for example, the flow path area is the product of the length of the channel, the width of the channel, and the number of channels.

[0089] Additionally, as an example, such as Figure 2As shown, the gas supply port 8 includes an anode gas supply port 8a, a cathode gas supply port 8b, and a cooling medium gas supply port 8c. The gas supply ports 8 of the anode-side spacers 4a and the cathode-side spacers 4b are interconnected when the fuel cell units 10 are stacked, extending continuously along the stacking direction of the fuel cell units 10. The anode gas supply port 8a is connected to the anode gas flow path 5a, supplying hydrogen-containing fuel gas to the anode gas flow path 5a from a supply pipe (not shown) connected to the outside of the fuel cell stack, and discharging anode gas from the anode gas flow path 5a. The cathode gas supply port 8b is connected to the cathode gas flow path 5b, supplying air-containing oxidant gas to the cathode gas flow path 5b from a supply pipe, and discharging oxidant gas from the cathode gas flow path 5b. The cooling medium gas supply port 8c is connected to the cooling medium flow path 7, supplying cooling medium to the cooling medium flow path 7 from a supply pipe, and discharging cooling medium from the cooling medium flow path 7.

[0090] The anode-side gas diffusion layer 3a has: a first low elastic modulus portion 5', opposite to the first gas flow path portion 5 of the anode-side spacer 4a; and a first high elastic modulus portion 6', opposite to the second gas flow path portion 6 of the anode-side spacer 4a, having a higher compressive elastic modulus in the thickness direction than the first low elastic modulus portion 5'. The cathode-side gas diffusion layer 3b has: a second low elastic modulus portion 15', opposite to the third gas flow path portion 15 of the cathode-side spacer 4b; and a second high elastic modulus portion 16', opposite to the fourth gas flow path portion 16 of the cathode-side spacer 4b, having a higher compressive elastic modulus in the thickness direction than the second low elastic modulus portion 15'.

[0091] The anode-side gas diffusion layer 3a and the cathode-side gas diffusion layer 3b each have high elastic modulus portions 6' and 16', thus suppressing deformation and expansion of the anode-side gas diffusion layer 3a and the cathode-side gas diffusion layer 3b. As a result, sufficient space is ensured between the anode-side spacer 4a and the anode-side gas diffusion layer 3a in the second gas flow path 6, and between the cathode-side spacer 4b and the cathode-side gas diffusion layer 3b in the fourth gas flow path 16. This improves water discharge performance of the fuel cell unit 10 and reduces pressure loss. Therefore, the fuel cell unit 10 exhibits excellent power generation performance.

[0092] Additionally, as an example, such as Figure 2 As shown, the second gas flow path 6 and the fourth gas flow path 16 are respectively configured to be disposed between the gas supply hole 8 and the first gas flow path 5 and the third gas flow path 15, and function as flow straighteners to regulate the flow of the fluid flowing inside. Furthermore, the second gas flow path 6 and the fourth gas flow path 16 can be disposed either in-plane or out-of-plane on the electrode composed of the gas diffusion layer and the catalyst layer.

[0093] (Second Implementation)

[0094] Figure 4 The fuel cell cell 10 according to the second embodiment of this disclosure is along Figure 1 A cross-sectional view along line III-III. In the fuel cell cell 10 of the second embodiment, the flow path areas viewed from above along the stacking direction of the MEA20 are different in the second gas flow path 6 disposed upstream of the first gas flow path 5, the fourth gas flow path 16 disposed upstream of the third gas flow path 15, the second gas flow path 6 disposed downstream of the first gas flow path 5, and the fourth gas flow path 16 disposed downstream of the third gas flow path 15. Furthermore, in the second embodiment, the same symbols are used to denote the same structures as in the first embodiment, and their descriptions are omitted.

[0095] like Figure 4 As shown, in the fuel cell cell 10 of the second embodiment, the flow path area viewed from above along the stacking direction of MEA20 increases in the following order: first gas flow path 5, second gas flow path 6 upstream of first gas flow path 5, and second gas flow path 6 downstream of first gas flow path 5.

[0096] Furthermore, in the fuel cell cell 10 of the second embodiment, the flow path area viewed from above along the stacking direction of the MEA20 increases in the following order: the third gas flow path 15, the fourth gas flow path 16 upstream of the third gas flow path 15, and the fourth gas flow path 16 downstream of the third gas flow path 15.

[0097] Furthermore, in the two embodiments described above, high elastic modulus portions 6' and 16' are formed on both the anode-side gas diffusion layer 3a and the cathode-side gas diffusion layer 3b. However, it is also possible to provide high elastic modulus portions 6' and 16' on at least one of the anode-side gas diffusion layer 3a and the cathode-side gas diffusion layer 3b. In this case, the power generation performance of the fuel cell unit 10 can also be improved. However, from the viewpoint of achieving a fuel cell unit 10 with higher power generation performance, it is preferable to form high elastic modulus portions 6' and 16' on both the anode-side gas diffusion layer 3a and the cathode-side gas diffusion layer 3b.

[0098] The polymer electrolyte membrane 1 can use a proton-conductive material that can selectively transport hydrogen ions, such as a perfluorocarbon sulfonic acid polymer.

[0099] The anode catalyst layer 2a and the cathode catalyst layer 2b can each be a layer containing carbon materials supported on catalyst particles such as platinum and a polymer electrolyte.

[0100] Both the anode-side gas diffusion layer 3a and the cathode-side gas diffusion layer 3b can use sheets with high gas permeability, with carbon as the main component.

[0101] The anode-side spacer 4a and the cathode-side spacer 4b can each be made of carbon-based or metal-based materials.

[0102] In the fuel cell cell 10 of the first and second embodiments, a cooling medium flow path 7 is formed only in the cathode-side spacer 4b, but it is preferable that a cooling medium flow path is also formed in the anode-side spacer 4a.

[0103] The second gas flow path 6 and the fourth gas flow path 16 are respectively configured to uniformly distribute fuel gas from the gas supply hole to the first gas flow path 5 and uniformly distribute oxidant gas to the third gas flow path 15. The first rib 43 between adjacent first grooves 42 and the second rib 54 between adjacent second grooves 52 can be formed in any shape, such as a line or an island. The contact area between the first rib 43 of the second gas flow path 6 and the anode-side gas diffusion layer 3a is smaller than the contact area between the first rib 43 of the first gas flow path 5 and the anode-side gas diffusion layer 3a. Furthermore, the contact area between the second rib 54 of the fourth gas flow path 16 and the cathode-side gas diffusion layer 3b is smaller than the contact area between the second rib 54 of the third gas flow path 15 and the cathode-side gas diffusion layer 3b. That is, the anode-side gas diffusion layer 3a is formed such that the area of ​​the surface opposite to the anode-side spacer 4a has the same surface area as the surface 41a and the first groove 42 of the anode-side spacer 4a constituting the first gas flow path 5, or the surface 41a and the first groove 42 of the anode-side spacer 4a constituting the first gas flow path 5 and the second gas flow path 6, or has an area larger than these surface areas. Similarly, the cathode-side gas diffusion layer 3b is formed such that the area of ​​the surface opposite to the cathode-side spacer 4b has the same surface area as the surface 51a and the second groove 52 of the cathode-side spacer 4b constituting the third gas flow path 15, or the surface 51a and the second groove 52 of the cathode-side spacer 4b constituting the third gas flow path 15 and the fourth gas flow path 16, or has an area larger than these surface areas.

[0104] In the anode-side gas diffusion layer 3a and the cathode-side gas diffusion layer 3b, the compressive elastic modulus of the high elastic modulus portions 6' and 16' is preferably 3.0 N / mm². 2 The above is achieved by setting the compressive modulus of the high-elasticity portions 6' and 16' of the anode-side gas diffusion layer 3a and the cathode-side gas diffusion layer 3b to 3.0 N / mm². 2As described above, the high elastic modulus portions 6' and 16' of the anode-side gas diffusion layer 3a and the cathode-side gas diffusion layer 3b are not easily deformed, and the second gas flow path 6 and the fourth gas flow path 16 are not easily blocked. Therefore, water accumulation is less likely to occur in the second gas flow path 6 and the fourth gas flow path 16. Furthermore, since the second gas flow path 6 and the fourth gas flow path 16 are not easily blocked, the pressure loss of the second gas flow path 6 and the fourth gas flow path 16 can be further reduced.

[0105] In the anode-side gas diffusion layer 3a and the cathode-side gas diffusion layer 3b, the porosity of the low elastic modulus portions 5' and 15' is preferably 65% ​​or more and 75% or less. By making the porosity of the low elastic modulus portions 5' and 15' 65% or more, gas diffusivity is improved, and a sufficient water discharge path is ensured, thus reducing the likelihood of overflow and further improving the cell performance of the fuel cell unit 10. Furthermore, by making the porosity of the low elastic modulus portions 5' and 15' 75% or less, good electrical conductivity and water retention are achieved, further improving the cell performance of the fuel cell unit 10.

[0106] In the anode-side gas diffusion layer 3a and the cathode-side gas diffusion layer 3b, the porosity of the high elastic modulus portions 6' and 16' is preferably 65% ​​or more and 70% or less. By ensuring that the porosity of the high elastic modulus portions 6' and 16' is 65% or more, good gas diffusion and sufficient water discharge path can be ensured, and deformation of the high elastic modulus portions 6' and 16' can be suppressed, thus further improving the cell performance of the fuel cell unit 10. Furthermore, by ensuring that the porosity of the high elastic modulus portions 6' and 16' is 70% or less, the high elastic modulus portions 6' and 16' have good electrical conductivity and water retention, thus further improving the cell performance of the fuel cell unit 10.

[0107] The porosity of the anode-side gas diffusion layer 3a and the cathode-side gas diffusion layer 3b can be determined by the following method. First, the apparent true density of the anode-side gas diffusion layer 3a and the cathode-side gas diffusion layer 3b is calculated based on the true density and composition ratio of each material in the anode-side gas diffusion layer 3a and the cathode-side gas diffusion layer 3b. Next, the weight, thickness, and longitudinal and transverse dimensions of the manufactured anode-side gas diffusion layer 3a and the cathode-side gas diffusion layer 3b are measured, and their densities are calculated. Then, the porosity of the anode-side gas diffusion layer 3a and the cathode-side gas diffusion layer 3b is calculated using the formula: Porosity = (Density of anode-side gas diffusion layer 3a or cathode-side gas diffusion layer 3b) / (Apparent True Density) × 100.

[0108] The contact angles of the anode-side gas diffusion layer 3a and the cathode-side gas diffusion layer 3b with respect to water are preferably 150 degrees or more. That is, the water contact angles on the surfaces of the low elastic modulus portions 5' and 15' and the high elastic modulus portions 6' and 16' of the anode-side gas diffusion layer 3a and the cathode-side gas diffusion layer 3b are preferably 150 degrees or more. When the contact angles of the anode-side gas diffusion layer 3a and the cathode-side gas diffusion layer 3b are 150 degrees or more, the surfaces of the anode-side gas diffusion layer 3a and the cathode-side gas diffusion layer 3b have excellent hydrophobicity, and water is less likely to remain on the surfaces of the anode-side gas diffusion layer 3a and the cathode-side gas diffusion layer 3b. Therefore, the gas permeability of the anode-side gas diffusion layer 3a and the cathode-side gas diffusion layer 3b is further improved.

[0109] The anode-side gas diffusion layer 3a and the cathode-side gas diffusion layer 3b each preferably have a Graley number of 50 sec / 100 mL or more and 150 sec / 100 mL or less. Specifically, it is preferable that the low elastic modulus portions 5' and 15' and the high elastic modulus portions 6' and 16' of both the anode-side gas diffusion layer 3a and the cathode-side gas diffusion layer 3b have a Graley number of 50 sec / 100 mL or more and 150 sec / 100 mL or less. The reason for this is that by ensuring that the Graley number of the low elastic modulus portions 5' and 15' and the high elastic modulus portions 6' and 16' is 50 sec / 100 mL or more, the water retention capacity is less likely to decrease under low humidification conditions, thus preventing an increase in proton resistance and improving the cell performance of the fuel cell unit 10. Furthermore, by setting the Greuley number of the low elastic modulus portions 5' and 15' and the high elastic modulus portions 6' and 16' to 150 sec / 100 mL or less, the gas permeability of the gas diffusion layer and the water expulsion capability can be sufficiently ensured, thereby further improving the cell performance of the fuel cell unit 10.

[0110] In addition, the Greuley number is a value measured as follows: When an inner cylinder containing gas is placed inside an outer cylinder filled with oil, the inner cylinder gradually descends inside the outer cylinder due to its own weight, and the gas inside is compressed. The time required for a certain volume (100 mL) of gas to pass through a test piece placed inside the outer cylinder is measured and recorded as the Greuley number.

[0111] In the anode-side gas diffusion layer 3a and the cathode-side gas diffusion layer 3b, it is preferable that the low elastic modulus portions 5' and 15' are a single layer, and the high elastic modulus portions 6' and 16' are a two-layer structure. As will be explained by the manufacturing method described later, the high elastic modulus portions 6' and 16' can be formed by stacking two rolled sheets obtained by rolling the materials of the anode-side gas diffusion layer 3a and the cathode-side gas diffusion layer 3b and then re-rolling them. That is, by making the high elastic modulus portions 6' and 16' a two-layer structure, the high elastic modulus portions 6' and 16' can be easily formed.

[0112] In the anode-side gas diffusion layer 3a and the cathode-side gas diffusion layer 3b, the thicknesses (in other words, the dimensions in the stacking direction of the MEA20) of the low elastic modulus portions 5' and 15' and the high elastic modulus portions 6' and 16' are preferably different. More specifically, it is more preferable that the thickness of the high elastic modulus portions 6' and 16' is thinner than the thickness of the low elastic modulus portions 5' and 15'. By making the thickness of the high elastic modulus portions 6' and 16' thinner than the thickness of the low elastic modulus portions 5' and 15', the second gas flow path portion 6 and the fourth gas flow path portion 16 are particularly less prone to blockage.

[0113] <Manufacturing Method of Fuel Cell Unit>

[0114] Next, the manufacturing method of the fuel cell unit 10 disclosed herein will be described. Here, based on Figure 5 The flowchart illustrates the manufacturing methods of the anode-side gas diffusion layer 3a and the cathode-side gas diffusion layer 3b.

[0115] In step S1, the raw materials for manufacturing the gas diffusion layer, such as carbon material as conductive particles, carbon nanotubes as conductive fibers, surfactants, and dispersing solvents, are mixed. After mixing the carbon material, carbon nanotubes, surfactants, and dispersing solvents, PTFE is added as a fluoropolymer, and the mixture is mixed again to obtain a compound. Furthermore, if different compositions of raw materials are used in the low elastic modulus portions 5' and 15' and the high elastic modulus portions 6' and 16' of the manufactured gas diffusion layer, the compound can be prepared simply by mixing the respective raw materials.

[0116] The mixing of raw materials in step S1 can be performed using, for example, a planetary mixer, a rotary mixer, a kneader, or a roller mill.

[0117] In step S2, the compound obtained in step S1 is rolled into a sheet. In the rolling process of step S2, a rolling mill can be used, for example. For example, by using rolling conditions from 0.001 ton / cm to 4 ton / cm, one or more rolling passes can be performed to adjust the thickness, porosity, and elastic modulus of the manufactured gas diffusion layer. Furthermore, when different compositions of raw materials are used for the low elastic modulus portions 5' and 15' and the high elastic modulus portions 6' and 16' of the manufactured gas diffusion layer, rolled sheets for forming the low elastic modulus portions 5' and 15' and for forming the high elastic modulus portions 6' and 16' can be manufactured separately by rolling the compound prepared according to the respective raw materials. Moreover, as described later, when the high elastic modulus portions 6' and 16' are configured as a two-layer structure, rolled sheets with shapes corresponding to the manufactured gas diffusion layer and those corresponding to the high elastic modulus portions 6' and 16' can be manufactured separately from the same compound.

[0118] In step S3, low elastic modulus portions 5' and 15' and high elastic modulus portions 6' and 16' are formed, and then rolled. Here, based on Figures 5-11 This explains the three methods for performing step S3.

[0119] First, use Figure 6 as well as Figure 7 , to explain Figure 5 The first method of step S3. Figure 6 (A) represents a top view of the gas diffusion layer 30 created in step S2. Figure 6 (B) represents a cross-sectional view of the gas diffusion layer 30 fabricated in step S2. Figure 6 as well as Figure 7 In the method shown, firstly, the raw materials of the low elastic modulus portions 5' and 15' are mixed, and the resulting mixture is rolled to form a first rolled sheet 31 with a shape corresponding to the low elastic modulus portions 5' and 15'. Next, the raw materials of the high elastic modulus portions 6' and 16', which have a different composition from the raw materials of the low elastic modulus portions 5' and 15', are mixed, and the resulting mixture is rolled to form a second rolled sheet 32 ​​with a shape corresponding to the high elastic modulus portions 6' and 16'. Then, the first rolled sheet 31 is positioned at locations corresponding to the first gas flow path portion 5 and the third gas flow path portion 15, and the second rolled sheet 32 ​​is positioned at locations corresponding to the second gas flow path portion 6 and the fourth gas flow path portion 16. The first rolled sheet 31 and the second rolled sheet 32 ​​are then rolled. This forms a sheet with... Figure 7 The rolled sheets shown are the low elastic modulus portions 5' and 15' and the high elastic modulus portions 6' and 16'.

[0120] Next, use Figure 8 as well as Figure 9 , to explain Figure 5 The second method of step S3. Figure 8 (A) represents a top view of the gas diffusion layer 30 created in step S2. Figure 9 (B) represents a cross-sectional view of the gas diffusion layer 30 fabricated in step S2. Figure 8 as well as Figure 9In the method shown, firstly, a compound made by mixing specified raw materials (e.g., the raw materials of low elastic modulus portions 5' and 15') is rolled to form a first rolled sheet 31 with a shape corresponding to the manufactured gas diffusion layer. Next, a compound made by mixing the same raw materials as the first rolled sheet 31 is rolled to form a second rolled sheet 32 ​​with a shape corresponding to the high elastic modulus portions 6' and 16'. Then, the second rolled sheet 32 ​​is overlapped onto the portions of the first rolled sheet 31 corresponding to the second gas flow path portion 6 and the fourth gas flow path portion 16, and the first rolled sheet 31 and the second rolled sheet 32 ​​are rolled. Thus, a gas diffusion layer with... Figure 9 The rolled sheets shown are the low elastic modulus portions 5' and 15' and the high elastic modulus portions 6' and 16'.

[0121] Next, use Figure 10 as well as Figure 11 Explanation Figure 5 The third method in step 3. Figure 10 (A) represents a top view of the gas diffusion layer 30 created in step S2. Figure 10 (B) represents a cross-sectional view of the gas diffusion layer 30 fabricated in step S2. Figure 10 as well as Figure 11 In the method shown, firstly, a compound made by mixing raw materials of low elastic modulus portions 5' and 15' is rolled to form a first rolled sheet 31 with a shape corresponding to the manufactured gas diffusion layer. Next, a resin sheet 9 is laminated onto portions of the first rolled sheet 31 corresponding to the second gas flow path portion 6 and the fourth gas flow path portion 16, and the first rolled sheet 31 and the resin sheet 9 are rolled together. Thus, a gas diffusion layer with... Figure 11 The rolled sheets shown are of low elastic modulus portions 5' and 15' and high elastic modulus portions 6' and 16'. Additionally, Kapton sheet can be used as the material for the resin sheet 9, for example.

[0122] In the rolling process of step S3, a rolling mill can be used, for example. For example, by using rolling conditions of 0.01 ton / cm to 4 ton / cm, one or more rolling passes can be performed to adjust the thickness, porosity, and elastic modulus of the anode-side gas diffusion layer 3a and the cathode-side gas diffusion layer 3b.

[0123] In step S4, the sheet rolled in step S3 is fired to remove the surfactant and dispersing solvent.

[0124] In the firing process of step S4, an IR furnace or a hot air drying furnace can be used, for example. The firing temperature is preferably set to be higher than the decomposition temperature of the surfactant and lower than the melting temperature of the fluoropolymer. The reason is as follows: By setting the firing temperature higher than the decomposition temperature of the surfactant, the surfactant is less likely to remain in the anode-side gas diffusion layer 3a and the cathode-side gas diffusion layer 3b, thus preventing hydrophilication of the interior of the anode-side gas diffusion layer 3a and the cathode-side gas diffusion layer 3b. As a result, anode-side gas diffusion layer 3a and cathode-side gas diffusion layer 3b that are less prone to water retention can be obtained, improving the gas permeability of the gas diffusion layer. Furthermore, by setting the firing temperature lower than the melting point of the fluoropolymer, the fluoropolymer in the raw material is less likely to melt, preventing a decrease in the strength of the anode-side gas diffusion layer 3a and the cathode-side gas diffusion layer 3b. Specifically, for example, when PTFE is used as the fluoropolymer, the firing temperature is preferably 280–340°C.

[0125] In step S5, the sheet from which the surfactant and dispersing solvent have been removed is further rolled using a rolling mill to adjust the thickness. This allows the fabrication of the anode-side gas diffusion layer 3a and the cathode-side gas diffusion layer 3b.

[0126] In the re-rolling process of step S5, a rolling mill can be used, for example. For example, by using rolling conditions of 0.01 ton / cm to 4 ton / cm, one or more re-rolling processes can be performed to further adjust the thickness, porosity, and elastic modulus of the anode-side gas diffusion layer 3a and the cathode-side gas diffusion layer 3b.

[0127] The MEA20 obtained by using the anode-side gas diffusion layer 3a and the cathode-side gas diffusion layer 3b obtained in this way is clamped with a pair of spacers, and a fuel cell cell 10 can be manufactured.

[0128] This disclosure is not limited to the above-described embodiments and can be implemented in various other ways.

[0129] [Example]

[0130] The embodiments of this disclosure will be described below.

[0131] <Fabrication of the Gas Diffusion Layer>

[0132] (raw material)

[0133] Conductive particles: Acetylene black (hereinafter referred to as AB) (manufactured by Electrochemical Industry)

[0134] Conductive fiber: VGCF (Showa Denko, VGCF-H)

[0135] Fluoropolymer: PTFE dispersion (manufactured by DAIKIN)

[0136] (Example 1)

[0137] use Figure 5 The first method of step S3 is as follows to prepare the gas diffusion layer. Conductive particles and conductive fibers are dispersed and mixed with a surfactant and water, then added to a fluoropolymer resin, and stirred and mixed again to obtain a compound. Next, the compound is rolled three times using a rolling mill at a rolling rate of 0.1 ton / cm to obtain a rolled sheet with a porosity of approximately 71%. Similarly, the compound is rolled four times using a rolling mill at a rolling rate of 0.1 ton / cm to obtain a rolled sheet with a porosity of approximately 66%. The rolled sheet with a porosity of approximately 71% is positioned to correspond to the first gas flow path 5, and the rolled sheet with a porosity of approximately 66% is positioned to correspond to the second gas flow path 6. The compound is then rolled once using a rolling mill at a rolling rate of 0.1 ton / cm. The rolled sheet is placed in an IR furnace and fired at 300°C for 0.5 hours. The gas diffusion layer of Example 1 was obtained by rolling the sheet fired at 1 ton / cm using a roller press.

[0138] (Example 2)

[0139] use Figure 5 The second method of step S3 is as follows to produce the gas diffusion layer. A compound is obtained using the same method as in Example 1. Next, the compound is rolled three times using a rolling mill at a rolling condition of 0.1 ton / cm to obtain a rolled sheet with a porosity of approximately 70%. On the rolled sheet with a porosity of approximately 70%, two rolled sheets with a porosity of approximately 70% are stacked only at the position corresponding to the second gas flow path 6, forming two layers. Then, the same process as in Example 1 is performed under the same conditions to obtain the gas diffusion layer of Example 2.

[0140] (Example 3)

[0141] use Figure 5 The third method for step S3 is as follows to prepare the gas diffusion layer. A compound is obtained using the same method as in Example 1. Next, the compound is rolled three times using a rolling mill at a rolling condition of 0.1 ton / cm to obtain a rolled sheet with a porosity of approximately 72%. A resin sheet 9 (manufactured by DU PONT-TORAY Co., Ltd., Kapton sheet, 100 μm thick) is laminated only on the rolled sheet with a porosity of approximately 72% at the position corresponding to the second gas flow path 6. Then, the same process as in Example 1 is performed under the same conditions to obtain the gas diffusion layer of Example 3.

[0142] (Comparative Example 1)

[0143] The compound was obtained using the same method as in Example 1. Next, the compound was rolled three times using a rolling mill at a rolling condition of 0.1 ton / cm to obtain a rolled sheet with a porosity of approximately 73%. The rolled sheet was placed in an IR furnace and fired at 300°C for 0.5 hours. The fired sheet was then rolled three times using a rolling mill at a rolling condition of 1 ton / cm to obtain the gas diffusion layer of Comparative Example 1.

[0144] <Evaluation Experiment>

[0145] The following evaluation tests were conducted on the gas diffusion layers of Examples 1-3 and Comparative Example 1. For Examples 1-3, evaluation tests were performed on both the low elastic modulus portion 5' corresponding to the first gas flow path portion 5 and the high elastic modulus portion 6' corresponding to the second gas flow path portion 6 of the spacer. The results are shown below. Figure 12 .

[0146] (Compressive modulus)

[0147] The compressive modulus of elasticity was determined using the following method. A tensile compression testing machine (SVZ-200NB model manufactured by Imada Seisakusho) was used to test a 6.42 cm... 2 A gas diffusion layer of 20 kgf / cm² is applied. 2 The load is calculated, stress and strain are determined, and the compressive modulus is measured.

[0148] (film thickness)

[0149] The film thickness was determined using the following method. A Mitutoyo thickness gauge was used to measure 6.42 cm. 2 The film thickness at 5 locations of the gas diffusion layer is the size of the film thickness, and the average value is set as the film thickness.

[0150] (Porosity)

[0151] Porosity was determined using the following method. The apparent true density of the gas diffusion layer was calculated based on the true density and composition ratio of each material in the layer. Next, the weight, thickness, and dimensions of the gas diffusion layer were measured, and its density was calculated. The porosity was then calculated using the formula: Porosity = (Density of Gas Diffusion Layer) / (Apparent True Density) × 100.

[0152] (Contact angle)

[0153] The contact angle was measured using the following method. The static contact angle relative to pure water was measured using a portable contact angle meter (MATSUBO PG-X).

[0154] (Greece number)

[0155] The Greuther number was determined using the following method. An apparatus was used: an outer cylinder filled with oil and an inner cylinder sealed with gas. When the inner cylinder was inserted into the outer cylinder, it gradually descended due to its own weight, compressing the gas inside. A 6.42 cm [unclear text - possibly a unit of measurement] was placed inside the outer cylinder of this apparatus. 2 The size of the gas diffusion layer is determined, and the time required for 100 mL of gas to pass through the gas diffusion layer set inside the outer cylinder is recorded as the Gurley number.

[0156] like Figure 12 As shown, in Examples 1-3, the compressive modulus of the high-modulus portion 6' of the spacer corresponding to the second gas flow path 6 is greater than that of the low-modulus portion 5' corresponding to the first gas flow path 5. However, in Comparative Example 1, the overall compressive modulus of the gas diffusion layer is constant. Furthermore, Examples 1-3 have a Graley number of 150 sec / 100 mL or less, and the contact angle is also at the same level as Comparative Example 1. Therefore, even in regions with high compressive modulus, sufficient gas permeability can be ensured. Thus, in the gas diffusion layers of Examples 1-3, since a high-density layer with low porosity and high compressive modulus is formed in the region of the spacer corresponding to the second gas flow path 6, the high-density layer is not easily deformed, and sufficient space for the second gas flow path 6 of the spacer can be ensured, thereby suppressing the generation of water accumulation. Furthermore, even with the formation of a high-density layer, sufficient gas permeability of the gas diffusion layer itself can be ensured. That is, according to this disclosure, a fuel cell cell 10 with high power generation performance can be realized.

[0157] Industrial availability

[0158] The fuel cell unit disclosed herein can improve the power generation performance of fuel cells and reduce manufacturing costs. Therefore, the fuel cell unit disclosed herein is useful in applications such as residential combined heat and power systems, automotive fuel cells, mobile fuel cells, and backup fuel cells.

Claims

1. A fuel cell unit, comprising: The first spacer, the first gas diffusion layer, the first catalyst layer, the polymer electrolyte membrane, the second catalyst layer, the second gas diffusion layer, and the second spacer are sequentially stacked along the stacking direction. A first gas flow path is disposed between the first spacer and the first gas diffusion layer; and The second gas flow path is disposed between the first spacer and the first gas diffusion layer, and is adjacent to the first gas flow path in a direction intersecting the stacking direction. The flow path area, viewed from above along the stacking direction, is larger than that of the first gas flow path. The first gas diffusion layer has: A first low elastic modulus section is positioned opposite the first gas flow path section; and The first high elastic modulus portion, opposite the second gas flow path portion, has a higher compressive elastic modulus than the first low elastic modulus portion in the stacking direction. The first spacer has a gas supply port. The second gas flow path is disposed between the first gas flow path and the gas supply hole. The first low elastic modulus portion and the first high elastic modulus portion have different thicknesses, and the first high elastic modulus portion is located on both sides of the first low elastic modulus portion.

2. The fuel cell unit according to claim 1, wherein, The first low elastic modulus portion is a single-layer structure, and the first high elastic modulus portion is a two-layer structure.

3. A fuel cell unit, comprising: The first spacer, the first gas diffusion layer, the first catalyst layer, the polymer electrolyte membrane, the second catalyst layer, the second gas diffusion layer, and the second spacer are sequentially stacked along the stacking direction. A first gas flow path is disposed between the first spacer and the first gas diffusion layer; and The second gas flow path is disposed between the first spacer and the first gas diffusion layer, and is adjacent to the first gas flow path in a direction intersecting the stacking direction. The flow path area, viewed from above along the stacking direction, is larger than that of the first gas flow path. The first gas diffusion layer has: A first low elastic modulus section is positioned opposite the first gas flow path section; and The first high elastic modulus portion, opposite the second gas flow path portion, has a higher compressive elastic modulus than the first low elastic modulus portion in the stacking direction. The first spacer has a gas supply port. The second gas flow path is disposed between the first gas flow path and the gas supply hole. The first low elastic modulus portion is a single layer, and the first high elastic modulus portion is a two-layer structure, with the first high elastic modulus portion located on both sides of the first low elastic modulus portion.

4. The fuel cell unit according to any one of claims 1 to 3, wherein, It also has: A third gas flow path is disposed between the second spacer and the second gas diffusion layer; and A fourth gas flow path is disposed between the second spacer and the second gas diffusion layer, and is adjacent to the third gas flow path in a direction intersecting the stacking direction. The flow path area, viewed from above along the stacking direction, is larger than that of the third gas flow path. The second gas diffusion layer has: The second low elastic modulus section is opposite to the third gas flow path section; as well as The second high elastic modulus portion, opposite the fourth gas flow path portion, has a higher compressive elastic modulus than the second low elastic modulus portion in the stacking direction.

5. The fuel cell unit according to claim 4, wherein, The second low elastic modulus portion is a single-layer structure, and the second high elastic modulus portion is a two-layer structure.

6. The fuel cell unit according to claim 4, wherein, The second low elastic modulus portion and the second high elastic modulus portion have different dimensions in the lamination direction.

7. A fuel cell, comprising: The fuel cell unit according to any one of claims 1 to 6; and A pair of current collectors are respectively disposed on both sides of the stacking direction of the fuel cell unit.

8. A method for manufacturing a fuel cell unit, comprising the method for manufacturing a fuel cell unit according to any one of claims 1 to 6, comprising: The mixture made by mixing the raw materials of the first low elastic modulus portion is rolled to form a first rolled sheet with a shape corresponding to the first low elastic modulus portion. A compound made by mixing raw materials of a first high elastic modulus portion, which have a different composition from the raw materials of the first low elastic modulus portion, is rolled to form a second rolled sheet with a shape corresponding to the first high elastic modulus portion; and The first rolled sheet is positioned at a location corresponding to the first gas flow path, and the second rolled sheet is positioned at a location corresponding to the second gas flow path. Then, the first gas diffusion layer is formed by rolling the first rolled sheet and the second rolled sheet.

9. A method for manufacturing a fuel cell unit, comprising the method for manufacturing a fuel cell unit according to any one of claims 1 to 6, comprising: The first compound, made by mixing raw materials, is rolled to form a first rolled sheet with a shape corresponding to the first gas diffusion layer; The second compound, prepared by mixing the raw materials, is rolled to form a second rolled sheet with a shape corresponding to the first high elastic modulus portion; and The first gas diffusion layer is formed by stacking and rolling the first rolled sheet and the second rolled sheet together.

10. A method for manufacturing a fuel cell cell, comprising the method for manufacturing a fuel cell cell according to any one of claims 1 to 6, comprising: The mixture made by mixing the raw materials of the first low elastic modulus portion is rolled to form a first rolled sheet with a shape corresponding to the first low elastic modulus portion. The compound made by mixing the raw materials of the first high elastic modulus portion is rolled to form a second rolled sheet with a shape corresponding to the first high elastic modulus portion; and The first rolled sheet is positioned at a location corresponding to the first gas flow path, and the second rolled sheet is positioned at a location corresponding to the second gas flow path. Then, a resin sheet with a shape corresponding to the first high elastic modulus portion is stacked on the second rolled sheet, and the first gas diffusion layer is formed by rolling the first rolled sheet, the second rolled sheet, and the resin sheet.

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