MEA with resin frame and manufacturing method thereof

Abstract

The present invention provides an MEA with a resin frame and a manufacturing method thereof. In the MEA with a resin frame (10), the electrolyte membrane (26) has an outer peripheral overlapping portion (40) overlapping with the inner peripheral portion (24i) of the resin frame component (24). An ion flow blocking portion (50, 140) is provided in the outer peripheral overlapping portion. The ion flow blocking portion blocks the flow of iron ions or copper ions. The ion flow blocking portion is annular and surrounds the power generation area (44) of the MEA (22). The ion flow blocking portion can be formed as a physical barrier or a chemical barrier. Accordingly, it is possible to suppress the deterioration of the central area of ​​the electrolyte membrane due to the entry of ions from the outer peripheral side of the MEA.

Description

Technical Field

[0001] The present invention relates to an MEA with a resin frame and a manufacturing method thereof. Background Art

[0002] For example, Japanese Patent Publication No. 2006-85926 discloses a resin-framed MEA for a fuel cell power generation cell. The resin-framed MEA comprises an MEA and a resin frame member. The MEA includes an electrolyte membrane and a pair of electrodes disposed on either side of the electrolyte membrane. The resin frame member is provided on the outer periphery of the MEA so as to protrude outward from the outer periphery.

[0003] The MEA with a resin frame is sandwiched between a set of separators. This forms a power generation cell. The material of the separator set is, for example, a metal such as stainless steel. Summary of the Invention

[0004] When the raw material of the electrolyte membrane is a solid polymer, protons are conducted within the electrolyte membrane. This conduction occurs when the electrolyte membrane is in a wet state. Therefore, in order to keep the electrolyte membrane in a wet state, water vapor is mixed in the reaction gas supplied to the MEA. When the raw material of the separator is a metal material, part of the metal material may be dissolved into the water vapor. When the metal material is stainless steel, when dissolution occurs, iron ions (Fe 2+ ) or copper ions (Cu 2+ ) and other metal ions.

[0005] In the resin-framed MEA described above, the aforementioned metal ions may enter the central region of the electrolyte membrane (forming the power generation area of ​​the MEA) from the outer edges of the electrolyte membrane through the interior of the electrolyte membrane. If this occurs, the central region of the electrolyte membrane may deteriorate.

[0006] The purpose of the present invention is to solve the above-mentioned technical problems.

[0007] One embodiment of the present invention is a resin-framed MEA, which is an MEA for a power generation cell for a fuel cell, comprising an MEA and a resin frame member, wherein:

[0008] The MEA includes an electrolyte membrane, a first electrode disposed on a first surface of the electrolyte membrane, and a second electrode disposed on a second surface of the electrolyte membrane.

[0009] The resin frame member is attached to the outer periphery of the MEA so as to protrude outward from the outer periphery.

[0010] The electrolyte membrane has an outer peripheral overlapping portion overlapping the inner peripheral portion of the resin frame member.

[0011] An ion flow blocking portion for blocking ion flow is provided on the outer peripheral overlapping portion. The ion flow blocking portion has an annular shape surrounding the power generation region of the MEA.

[0012] Another embodiment of the present invention is a method for manufacturing a MEA with a resin frame, wherein the MEA with a resin frame is an MEA for a power generation cell for a fuel cell, the MEA with a resin frame comprising an MEA and a resin frame member, wherein:

[0013] The MEA includes an electrolyte membrane, a first electrode disposed on a first surface of the electrolyte membrane, and a second electrode disposed on a second surface of the electrolyte membrane.

[0014] The resin frame member is attached to the outer periphery of the MEA so as to protrude outward from the outer periphery.

[0015] The manufacturing method includes a lamination process, a bonding process and a blocking portion forming process, wherein:

[0016] In the lamination step, a laminate is obtained by laminating the electrolyte membrane on the first electrode;

[0017] In the joining step, the inner peripheral portion of the resin frame member is overlapped with the outer peripheral portion of the electrolyte membrane on which the first electrode is laminated to form an outer peripheral overlapping portion on the electrolyte membrane, and the inner peripheral portion of the resin frame member and the outer peripheral overlapping portion of the electrolyte membrane are joined;

[0018] In the blocking portion forming step, after the laminating step, an ion flow blocking portion for blocking ion flow is provided on the outer peripheral overlapping portion of the electrolyte membrane.

[0019] The ion flow blocking portion is formed into a ring shape surrounding the power generation region of the MEA.

[0020] According to the present invention, an ion flow blocking portion, which blocks ion flow, is located on the outer periphery of the MEA. This ion flow blocking portion prevents ions from entering the central region of the electrolyte membrane from the outer periphery. This prevents deterioration of the central region of the electrolyte membrane due to ions entering from the outer periphery of the MEA.

[0021] The above-mentioned objects, features, and advantages will be easily understood from the following description of the embodiments with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is an exploded perspective view of a power generation cell including a resin-framed MEA according to the first embodiment of the present invention.

[0023] Figure 2 It is along Figure 1A partially omitted longitudinal sectional view of II-II.

[0024] Figure 3A This is a flowchart illustrating a method for manufacturing the resin-frame MEA according to the first embodiment of the present invention. Figure 3B It is an explanation Figure 3A Flowchart of the filling and bonding process.

[0025] Figure 4 This is a three-dimensional diagram illustrating the lamination process.

[0026] Figure 5A This is a cross-sectional view illustrating the groove forming step. Figure 5B This is a perspective explanatory diagram of the processed laminate after the groove forming step.

[0027] Figure 6 This is a cross-sectional view illustrating the filling process.

[0028] Figure 7 This is a three-dimensional illustration of the joining process.

[0029] Figure 8 This is a cross-sectional view illustrating the joining process.

[0030] Figure 9 This is a flowchart illustrating a filling and bonding step according to a modification example.

[0031] Figure 10 yes Figure 9 Cross-sectional illustration of the coating process and the bonding process.

[0032] Figure 11 It is a partially omitted longitudinal sectional view of a power generation cell including a resin-framed MEA according to a modification of the first embodiment.

[0033] Figure 12 It is a longitudinal sectional view of a main part of a power generation cell including a resin-framed MEA according to a second embodiment of the present invention.

[0034] Figure 13 It is the chemical structural formula of perfluorosulfonic acid.

[0035] Figure 14 This is a flowchart illustrating a method for manufacturing a resin-frame MEA according to a second embodiment of the present invention.

[0036] Figure 15 It is an enlarged cross-sectional view of a main part showing a state where a laminated body is formed.

[0037] Figure 16 It is an enlarged cross-sectional view of a main part showing a state where a laminated body is hot-pressed.

[0038] Figure 17This is an enlarged cross-sectional view of a main part showing a state where a liquid (solution) is applied on the electrolyte membrane and the second electrode.

[0039] Figure 18 It is a partially omitted longitudinal cross-sectional view of a power generation cell having a resin-framed MEA having an ion flow blocking portion as a physical barrier and an ion flow blocking portion as a chemical barrier. DETAILED DESCRIPTION

[0040] Figure 1 This is an exploded perspective view of a power generation cell 12 having a resin-framed MEA 10 according to the first embodiment. The power generation cell 12 is a single cell of a fuel cell stack 14. The fuel cell stack 14 includes a plurality of power generation cells 12. The plurality of power generation cells 12 are stacked in the direction of arrow A. The fuel cell stack 14 is mounted on a fuel cell electric vehicle (not shown), for example, as an on-vehicle fuel cell stack.

[0041] The power generation cell 12 has a horizontally wide rectangular shape and includes a resin-framed MEA 10 (a resin-framed membrane electrode assembly), a first separator 16 , and a second separator 18 . The resin-framed MEA 10 is disposed between the first separator 16 and the second separator 18 .

[0042] The first and second partition members 16 and 18 are each formed by stamping a metal sheet into a corrugated cross-section. The metal sheet may be, for example, a steel sheet, a stainless steel sheet, an aluminum sheet, or a plated steel sheet. The metal sheet may be a stainless steel sheet or an aluminum sheet with a surface treatment for corrosion protection. The first and second partition members 16 and 18 are joined together by a plurality of joining lines (not shown) to form a joined partition 20.

[0043] exist Figure 1 and Figure 2 In FIG, the resin-framed MEA 10 includes an MEA 22 (membrane electrode assembly) and a resin frame member 24. The resin frame member 24 is attached to an outer peripheral portion 22o of the MEA 22 so as to protrude outward from the outer peripheral portion 22o.

[0044] like Figure 2 As shown, MEA 22 includes an electrolyte membrane 26, a first electrode 28, and a second electrode 30. The first electrode 28 is, for example, an anode. The second electrode 30 is, for example, a cathode. Conversely, the first electrode 28 may be a cathode and the second electrode 30 may be an anode.

[0045] The first electrode 28 is disposed on the first surface 26a of the electrolyte membrane 26. The second electrode 30 is disposed on the second surface 26b of the electrolyte membrane 26. The electrolyte membrane 26 is, for example, a solid polymer electrolyte membrane (cation exchange membrane). The solid polymer electrolyte membrane is, for example, a thin film of perfluorosulfonic acid containing water. The electrolyte membrane 26 is sandwiched between the first electrode 28 and the second electrode 30. The electrolyte membrane 26 may also be a fluorine-based electrolyte or an HC (hydrocarbon)-based electrolyte.

[0046] The first electrode 28 includes a first electrode catalyst layer 32 and a first gas diffusion layer 34. The first electrode catalyst layer 32 is bonded to the first surface 26a of the electrolyte membrane 26. The first gas diffusion layer 34 is laminated on the first electrode catalyst layer 32. The second electrode 30 includes a second electrode catalyst layer 36 and a second gas diffusion layer 38. The second electrode catalyst layer 36 is bonded to the second surface 26b of the electrolyte membrane 26. The second gas diffusion layer 38 is laminated on the second electrode catalyst layer 36.

[0047] The first electrode catalyst layer 32 includes, for example, porous carbon particles with a platinum alloy supported on the surface. The porous carbon particles are physically bonded to each other via an ion-conductive polymer binder. In this state, the porous carbon particles are uniformly applied to the surface of the first gas diffusion layer 34. The second electrode catalyst layer 36 includes, for example, porous carbon particles with a platinum alloy supported on the surface. The porous carbon particles are physically bonded to each other via an ion-conductive polymer binder. In this state, the porous carbon particles are uniformly applied to the surface of the second gas diffusion layer 38. The first gas diffusion layer 34 and the second gas diffusion layer 38 include carbon paper, carbon cloth, or the like.

[0048] The resin frame member 24 has electrical insulating properties. Examples of the raw material of the resin frame member 24 include PPS (polyphenylene sulfide), PPA (polyphthalamide), PEN (polyethylene naphthalate), PES (polyethersulfone), LCP (liquid crystal polymer), PVDF (polyvinylidene fluoride), silicone resin, fluororesin, m-PPE (modified polyphenylene ether resin), PET (polyethylene terephthalate), PBT (polybutylene terephthalate), and modified polyolefins.

[0049] The resin frame member 24 is a square ring-shaped member (see Figure 1). The inner peripheral portion 24i of the resin frame member 24 is arranged between the outer peripheral portion 28o of the first electrode 28 and the outer peripheral portion 30o of the second electrode 30. Specifically, the inner peripheral portion 24i of the resin frame member 24 is clamped by the outer peripheral portion 26o of the electrolyte membrane 26 and the outer peripheral portion 30o of the second electrode 30. The first surface 24a of the resin frame member 24 faces the outer peripheral portion 26o of the electrolyte membrane 26. The second surface 24b of the resin frame member 24 faces the outer peripheral portion 30o of the second electrode 30. In addition, the inner peripheral portion 24i of the resin frame member 24 may also be clamped by the outer peripheral portion 26o of the electrolyte membrane 26 and the outer peripheral portion 28o of the first electrode 28.

[0050] The outer peripheral portion 26o of the electrolyte membrane 26 has an outer peripheral overlapping portion 40 that overlaps the inner peripheral portion 24i of the resin frame member 24. The outer peripheral overlapping portion 40 extends in an annular shape (square annular shape) along the inner peripheral portion 24i of the resin frame member 24. The outer peripheral portion 22o of the MEA 22 has a groove 42 that penetrates the outer peripheral overlapping portion 40 of the electrolyte membrane 26 in the thickness direction (direction of arrow A).

[0051] The groove 42 surrounds the power generation region 44 of the MEA 22. In other words, the groove 42 extends in an annular (square) shape along the outer circumference of the electrolyte membrane 26. Specifically, the groove 42 separates the electrolyte membrane 26 into a central region 46 (which forms the power generation region 44 of the MEA 22) and outer peripheral end portions 48. The power generation region 44 is the region of the MEA 22 where the first electrode 28 contacts the first surface 26a of the electrolyte membrane 26 and the second electrode 30 contacts the second surface 26b of the electrolyte membrane 26.

[0052] The groove 42 opens into the second surface 26b of the electrolyte membrane 26. The bottom 42a of the groove 42 is located within the first gas diffusion layer 34. That is, the groove 42 extends through the electrolyte membrane 26 and the first electrode catalyst layer 32 in the thickness direction. In other words, the depth D1 of the groove 42 is greater than the thickness D2 of the electrolyte membrane 26. The width W of the groove 42 is greater than the thickness D2 of the electrolyte membrane 26.

[0053] However, the depth D1 and width W of the groove 42 can be appropriately set. Specifically, the bottom 42a of the groove 42 may be located at the boundary between the first electrode catalyst layer 32 and the first gas diffusion layer 34. Alternatively, the bottom 42a of the groove 42 may be located within the first electrode catalyst layer 32. Furthermore, the bottom 42a of the groove 42 may be located at the boundary between the electrolyte membrane 26 and the first electrode catalyst layer 32. The groove 42 only needs to penetrate at least the electrolyte membrane 26.

[0054] A first ion flow blocking member 50 made of resin, which blocks the flow of ions (e.g., metal ions such as iron ions), is located within the groove 42. Specifically, in the first embodiment, the first ion flow blocking member 50 is provided as a physical body within the groove 42 of the outer peripheral overlapping portion 40 of the electrolyte membrane 26. Thus, the first ion flow blocking member 50 serves as a physical barrier.

[0055] In this case, the first ion flow blocking portion 50 is integrally connected to the resin adhesive layer 52. The adhesive layer 52 joins the outer peripheral overlapping portion 40 of the electrolyte membrane 26 and the inner peripheral portion 24i of the resin frame member 24 to each other. That is, the first ion flow blocking portion 50 is formed by filling the groove 42 with the adhesive 54 forming the adhesive layer 52 and curing it. In addition, the first ion flow blocking portion 50 can also be separated from the adhesive layer 52 without being integrally connected. In addition, the resin material and the adhesive 54 constituting the first ion flow blocking portion 50 can also be different raw materials. Moreover, the raw material of the first ion flow blocking portion 50 can also be an inorganic material.

[0056] The adhesive 54 may be a liquid or a solid. Furthermore, the adhesive 54 may be a thermosetting resin or a thermoplastic resin. Specifically, examples of the resin material used for the adhesive 54 (the resin material forming the first ion flow blocking portion 50) include silicone resins, fluororesins, and epoxy resins.

[0057] In such a resin-framed MEA 10, the first surface 24a of the resin frame member 24 is bonded to the peripheral overlapping portion 40 of the electrolyte membrane 26 via the adhesive layer 52. The second surface 24b of the resin frame member 24 abuts (contacts) the outer peripheral portion 30o of the second electrode 30.

[0058] like Figure 1 As shown, each power cell 12 has an oxidant gas supply manifold 60a, a coolant supply manifold 62a, and a fuel gas exhaust manifold 64b at one end in the longitudinal direction. The one end in the longitudinal direction of each power cell 12 corresponds to the end in the direction of arrow B1. The oxidant gas supply manifold 60a, the coolant supply manifold 62a, and the fuel gas exhaust manifold 64b are arranged along the transverse direction of each power cell 12. The transverse direction of each power cell 12 extends in the direction of arrow C.

[0059] Through the oxidant gas supply passage 60a, an oxidant gas (e.g., oxygen-containing gas) as one reactant gas flows in the direction of arrow A2. Through the coolant supply passage 62a, a coolant (e.g., pure water, ethylene glycol, or oil) flows in the direction of arrow A2. Through the fuel gas discharge passage 64b, a fuel gas (e.g., hydrogen-containing gas) as another reactant gas flows in the direction of arrow A1.

[0060] The other longitudinal edge of each power generation cell 12 includes a fuel gas supply manifold 64a, a coolant discharge manifold 62b, and an oxidant gas discharge manifold 60b. The other longitudinal edge of each power generation cell 12 is the edge of each power generation cell 12 in the direction of arrow B2. The fuel gas supply manifold 64a, the coolant discharge manifold 62b, and the oxidant gas discharge manifold 60b are arranged in the direction of arrow C.

[0061] The fuel gas flows through the fuel gas supply passage 64a in the direction of arrow A2. The coolant flows through the coolant discharge passage 62b in the direction of arrow A1. The oxidant gas flows through the oxidant gas discharge passage 60b in the direction of arrow A1.

[0062] The number, arrangement, shape, and size of the aforementioned communication holes (such as the oxidant gas supply communication holes 60 a ) are not limited to the illustrated examples. The number, arrangement, shape, and size of the communication holes (such as the oxidant gas supply communication holes 60 a ) can be appropriately set according to the specifications required for the fuel cell stack 14 .

[0063] like Figure 1 and Figure 2 As shown, the first separator member 16 includes a first separator body 66 in the form of a metal plate. The first separator body 66 has a rectangular shape. An oxidant gas flow path 68 (reactant gas flow path) extending along the longitudinal direction (direction of arrow B) of the power generation cell 12 is stamped and formed on the surface 66a of the first separator body 66 that faces the resin-framed MEA 10. The oxidant gas flow path 68 fluidically connects the oxidant gas supply manifold 60a with the oxidant gas discharge manifold 60b. The oxidant gas flow path 68 supplies oxidant gas to the first electrode 28.

[0064] The second separator member 18 includes a second separator body 70 in the form of a metal plate. The second separator body 70 has a rectangular shape. A fuel gas flow path 72 (reactant gas flow path) extending along the longitudinal direction (direction of arrow B) of the power generation cell 12 is stamped and formed on the surface 70a of the second separator body 70 that faces the resin-framed MEA 10. The fuel gas flow path 72 connects the fuel gas supply manifold 64a to the fuel gas discharge manifold 64b. The fuel gas flow path 72 supplies fuel gas to the second electrode 30.

[0065] like Figure 1As shown, the coolant flow path 74 is located between the joined surface 66b of the first separator body 66 and the surface 70b of the second separator body 70. The coolant flow path 74 fluidically connects the coolant supply passage 62a with the coolant discharge passage 62b. The coolant flow path 74 is formed by overlapping the back surface of the first separator body 66, where the oxidant gas flow path 68 is formed, and the back surface of the second separator body 70, where the fuel gas flow path 72 is formed.

[0066] The power generation cell 12 configured in this manner operates as follows.

[0067] First, if Figure 1 As shown, the oxidant gas is supplied to the oxidant gas supply passage 60a, the fuel gas is supplied to the fuel gas supply passage 64a, and the cooling medium is supplied to the cooling medium supply passage 62a.

[0068] The oxidizing gas is introduced from the oxidizing gas supply passage 60 a into the oxidizing gas flow path 68 of the first separator member 16 . The oxidizing gas then moves in the direction of arrow B2 along the oxidizing gas flow path 68 and is supplied to the first electrode 28 of the MEA 22 .

[0069] On the other hand, Figure 1 As shown, the fuel gas is introduced from the fuel gas supply passage 64a into the fuel gas flow path 72 of the second separator member 18. The fuel gas then moves in the direction of arrow B1 along the fuel gas flow path 72 and is supplied to the second electrode 30 of the MEA 22.

[0070] Therefore, in each MEA 22 , the oxidant gas supplied to the first electrode 28 and the fuel gas supplied to the second electrode 30 are consumed by electrochemical reactions within the first electrode catalyst layer 32 and the second electrode catalyst layer 36 , thereby generating electric power.

[0071] Then, if Figure 1 As shown, the oxidant gas supplied to and consumed by the first electrode 28 flows from the oxidant gas flow path 68 to the oxidant gas discharge passage 60b. The oxidant gas is then discharged in the direction of arrow A1 along the oxidant gas discharge passage 60b. Similarly, the fuel gas supplied to and consumed by the second electrode 30 flows from the fuel gas flow path 72 to the fuel gas discharge passage 64b. The fuel gas is then discharged in the direction of arrow A1 along the fuel gas discharge passage 64b.

[0072] Water vapor is added to the fuel gas and the oxidant gas to keep the electrolyte membrane 26 in a moist state, so that the fuel gas and the oxidant gas have relatively high humidity.

[0073] The coolant supplied to the coolant supply passage 62a is introduced into the coolant flow path 74 formed between the first separator body 66 and the second separator body 70. After being introduced into the coolant flow path 74, the coolant flows in the direction indicated by arrow B2. After cooling the MEA 22, the coolant is discharged from the coolant discharge passage 62b.

[0074] Next, a method for manufacturing the resin-framed MEA 10 according to the first embodiment will be described.

[0075] like Figure 3A As shown, the method for manufacturing the resin-framed MEA 10 according to the first embodiment includes a stacking step, a groove forming step, and a filling and bonding step. As will be described later, the filling and bonding step includes a bonding step.

[0076] In the lamination process (step S1), as Figure 4 As shown, a laminate 80 is obtained by laminating the electrolyte membrane 26 on the first electrode 28. The electrolyte membrane 26 has the same planar dimensions (external dimensions) as the first electrode 28. Furthermore, during the lamination process, the first electrode 28 and the electrolyte membrane 26 are bonded to each other by hot pressing. Specifically, the electrolyte membrane 26 is laminated on the first electrode 28 while being heated and a load is applied.

[0077] In the stacked body 80 obtained by the stacking step, the first surface 26a of the electrolyte membrane 26 is in contact with the first electrode catalyst layer 32. In the stacked body 80, the second surface 26b of the electrolyte membrane 26 is exposed.

[0078] Next, in the groove forming step ( Figure 3A In step S2), as Figure 5A As shown in FIG. 1 , a processed stack 82 is formed by laser processing the stack 80. Specifically, in the groove forming step, a laser processing device 100 irradiates the outer peripheral portion 26o of the electrolyte membrane 26 (the second surface 26b of the electrolyte membrane 26) with a processing laser L. Then, the laser L is made to make a circle along the outer periphery of the electrolyte membrane 26. As a result, a square annular groove 42 (see FIG. 1 ) is formed in the outer peripheral portion 26o of the electrolyte membrane 26. Figure 5B ).

[0079] The method for forming the groove 42 is not limited to the laser processing described above. During the groove forming step, the groove 42 may be formed by mechanically processing the outer peripheral portion 26o of the electrolyte membrane 26 (the second surface 26b of the electrolyte membrane 26) using a cutter. Alternatively, during the groove forming step, the groove 42 may be formed by applying a chemical to the outer peripheral portion 26o of the electrolyte membrane 26 (the second surface 26b of the electrolyte membrane 26) to melt the electrolyte membrane 26.

[0080] Then, in the filling and bonding process ( Figure 3A In step S3), the groove 42 is filled with a resin material forming the first ion flow blocking portion 50 for blocking ion flow, and the inner peripheral portion 24i of the resin frame member 24 is joined to the outer peripheral portion 22o of the MEA 22. At this time, the groove 42 is covered by the inner peripheral portion 24i of the resin frame member 24, and the inner peripheral portion 24i of the resin frame member 24 overlaps the outer peripheral portion 26o of the electrolyte membrane 26.

[0081] Specifically, if Figure 3B As shown in FIG, the filling and bonding process includes a filling process and a bonding process. In the filling process (step S4), as shown in FIG. Figure 6 As shown, the groove 42 is filled with the adhesive 54 (resin material) supplied from the dispenser 102. At this time, the adhesive 54 is also applied to the outer surface of the outer peripheral portion 26o of the electrolyte membrane 26 (the second surface 26b of the electrolyte membrane 26).

[0082] In the bonding process ( Figure 3B In step S5), as Figure 7 As shown, a processed laminated body 82 obtained by the groove forming step, a resin frame member 24, and a second electrode 30 are prepared. Furthermore, one end edge portion of the resin frame member 24 has an oxidant gas supply passage 60a, a coolant supply passage 62a, and a fuel gas discharge passage 64b. The other end edge portion of the resin frame member 24 has a fuel gas supply passage 64a, a coolant discharge passage 62b, and an oxidant gas discharge passage 60b. The resin frame member 24 has an opening 84 in its center.

[0083] Next, the inner peripheral portion 24i of the resin frame member 24 is placed between the outer peripheral portion 26o of the electrolyte membrane 26 and the outer peripheral portion 30o of the second electrode 30, and the two are bonded together. This bonding is performed, for example, by hot pressing. Specifically, the first electrode 28, electrolyte membrane 26, resin frame member 24, and second electrode 30, which are stacked in the thickness direction, are heated and a load is applied thereto.

[0084] Therefore, if Figure 8 As shown, the second surface 26b of the electrolyte membrane 26 and the second electrode 30 are bonded to each other to form the MEA 22. In addition, an outer peripheral overlapping portion 40 is formed on the outer peripheral portion 26o of the electrolyte membrane 26 to overlap the inner peripheral portion 24i of the resin frame member 24.

[0085] Furthermore, since the adhesive 54 is sandwiched between the outer peripheral portion 26o of the electrolyte membrane 26 and the inner peripheral portion 24i of the resin frame member 24, the adhesive 54 flows toward the outside of the electrolyte membrane 26 and toward the inside (central region 46) of the electrolyte membrane 26. Then, as the adhesive 54 solidifies, an adhesive layer 52 is formed between the outer peripheral overlapping portion 40 of the electrolyte membrane 26 and the inner peripheral portion 24i of the resin frame member 24. Furthermore, the adhesive 54 filled in the groove 42 also solidifies. As a result, the first ion flow blocking portion 50 is formed. Thus, the resin frame MEA 10 is formed. After the bonding process is completed, the series of action flows of the method for manufacturing the resin frame MEA 10 are completed.

[0086] In the fuel cell stack 14 described above, ions may be generated from the components constituting the fuel cell stack 14. These ions may enter the space around the MEA 22. For example, the ions are iron ions (Fe ions) generated from the first separator 16 and the second separator 18. 2+ ) or copper ions (Cu 2+ ) and other metal ions. Such metal ions are generated when the metal components of the first separator member 16 and the second separator member 18 are dissolved in the water vapor contained in the reaction gas.

[0087] The first embodiment achieves the following effects.

[0088] The outer peripheral portion 22o of the MEA 22 has a groove 42 that penetrates the outer peripheral overlapping portion 40 in the thickness direction. A first ion flow blocking portion 50 for blocking ion flow is located in the groove 42. That is, the first ion flow blocking portion 50 is provided in the outer peripheral overlapping portion 40 of the electrolyte membrane 26.

[0089] With this configuration, the first ion flow blocking portion 50 is located in the outer peripheral overlapping portion 40 of the electrolyte membrane 26. This prevents iron ions, copper ions, and the like from entering the central region 46 (the portion forming the power generation region 44 of the MEA 22) from the outer peripheral end of the electrolyte membrane 26. This prevents deterioration of the central region 46 of the electrolyte membrane 26 due to ions entering from the outer peripheral side of the MEA 22.

[0090] The groove 42 and the first ion blocking portion 50 surround the power generation region 44 of the MEA 22 .

[0091] According to such a structure, it is possible to effectively suppress the entry of ions from the outer peripheral end of the electrolyte membrane 26 into the central region 46 .

[0092] The inner peripheral portion 24 i of the resin frame member 24 is sandwiched between the outer peripheral portion 28 o of the first electrode 28 and the outer peripheral portion 30 o of the second electrode 30 .

[0093] With this structure, the outer peripheral portion 26o of the electrolyte membrane 26 can be effectively covered by the resin frame member 24 and the outer peripheral portion 30o of the second electrode 30. Therefore, the introduction of ions from the outer peripheral portion 30o of the second electrode 30 into the electrolyte membrane 26 can be suppressed.

[0094] The first surface 24a of the resin frame member 24 is bonded to the outer peripheral overlapping portion 40 of the electrolyte membrane 26. The second surface 24b of the resin frame member 24 is bonded to the outer peripheral portion 30o of the second electrode 30.

[0095] This structure can suppress ions from flowing inward through the space between the first surface 24a of the resin frame 24 and the outer peripheral overlapping portion 40 of the electrolyte membrane 26. Also, it can suppress ions from flowing inward through the space between the second surface 24b of the resin frame 24 and the outer peripheral portion 30o of the second electrode 30.

[0096] The first ion flow blocking portion 50 is formed of an adhesive 54 that bonds the inner peripheral portion 24 i of the resin frame member 24 and the outer peripheral overlapping portion 40 of the electrolyte membrane 26 to each other.

[0097] According to such a configuration, the first ion blocking portion 50 can be formed by filling the groove 42 with the adhesive 54 , and thus the manufacturing process of the resin-framed MEA 10 can be simplified.

[0098] The outer peripheral portion 28o of the first electrode 28 overlaps the outer peripheral overlapping portion 40 of the electrolyte membrane 26. The groove 42 is formed in the outer peripheral overlapping portion 40 of the electrolyte membrane 26 and the outer peripheral portion 28o of the first electrode 28.

[0099] According to such a structure, it is possible to effectively suppress the entry of ions from the outer peripheral end of the electrolyte membrane 26 into the central region 46 .

[0100] The method for manufacturing the resin-framed MEA 10 includes a lamination process, a groove formation process, and a filling and bonding process. In the lamination process, the electrolyte membrane 26 is laminated onto the first electrode 28 to form a laminate 80. In the groove formation process, after the lamination process, grooves 42 are formed on the outer periphery of the laminate 80, penetrating the outer periphery 26o of the electrolyte membrane 26 in the thickness direction. In the filling and bonding process, the grooves 42 are filled with a resin material that forms the first ion flow blocking portion 50 for blocking ion flow. In this state, the inner periphery 24i of the resin frame member 24 is bonded to the outer periphery 22o of the MEA 22, such that the inner periphery 24i of the resin frame member 24 overlaps the outer periphery 26o of the electrolyte membrane 26. Furthermore, in the filling and bonding process, an outer peripheral overlapping portion 40 is formed on the outer periphery 26o of the electrolyte membrane 26, overlapping the inner periphery 24i of the resin frame member 24, with the grooves 42 located in the outer peripheral overlapping portion 40.

[0101] According to such a method, the resin-framed MEA 10 capable of suppressing the intrusion of ions from the outer peripheral end of the electrolyte membrane 26 into the central region 46 (the portion forming the power generation region 44 of the MEA 22 ) can be easily manufactured.

[0102] In the groove forming step, the groove 42 is formed in the outer peripheral portion 26 o of the electrolyte membrane 26 so that the groove 42 extends annularly along the outer periphery of the electrolyte membrane 26 .

[0103] According to such a method, it is possible to effectively suppress the entry of ions from the outer peripheral end of the electrolyte membrane 26 into the central region 46 .

[0104] In the groove forming step, the groove 42 is formed in the outer peripheral portion 26 o of the electrolyte membrane 26 by laser processing.

[0105] According to such a method, the groove 42 can be easily formed in the outer peripheral portion 26 o of the electrolyte membrane 26 .

[0106] The filling and bonding process includes a filling process and a bonding process. In the filling process, the groove 42 is filled with the adhesive 54. In the bonding process, after the filling process, the resin frame member 24 is bonded to the outer peripheral portion 22o of the MEA 22 by sandwiching the adhesive 54 between the outer peripheral overlap portion 40 of the electrolyte membrane 26 and the inner peripheral portion 24i of the resin frame member 24.

[0107] According to such a method, the adhesive 54 can be simply and reliably filled into the groove 42 in the filling step.

[0108] The method for manufacturing the resin frame MEA 10 according to the first embodiment is not limited to the above-mentioned method. Figure 9 As shown, the filling and joining process may also include a coating process and a joining process. In this case, in the coating process (step S6), as shown in FIG. Figure 10 As shown, a liquid adhesive 54 is applied to the inner peripheral portion of the first surface 24 a of the resin frame member 24 .

[0109] In the bonding process ( Figure 9 In step S7), after the coating process, the adhesive 54 is sandwiched between the outer peripheral overlapping portion 40 of the electrolyte membrane 26 and the inner peripheral portion 24i of the resin frame member 24. As a result, the adhesive 54 flows and fills (flows into) the groove 42, thereby bonding the inner peripheral portion 24i of the resin frame member 24 to the outer peripheral portion 22o of the MEA 22. This method can also manufacture the above-mentioned resin-framed MEA 10.

[0110] like Figure 11As shown, in the resin-framed MEA 10, the outer peripheral end of the second electrode 30 may be located inside the inner peripheral end of the resin frame member 24. That is, the inner peripheral portion 24i of the resin frame member 24 may not be sandwiched between the outer peripheral portion 28o of the first electrode 28 and the outer peripheral portion 30o of the second electrode 30.

[0111] Next, the second embodiment will be described. The configurations of elements not specifically described below are the same as those described in the first embodiment. Therefore, unless otherwise specified, the names and reference numerals used in the first embodiment will be used for each element.

[0112] Figure 12 This is a longitudinal cross-sectional view of the main parts of the power generation cell 110. The power generation cell 110 includes a resin-framed MEA 120 according to the second embodiment. The resin-framed MEA 120 includes an MEA 122 (membrane electrode assembly) and a resin frame member 124. The resin frame member 124 is attached to the outer peripheral portion 122o of the MEA 122 so as to protrude outward from the outer peripheral portion 122o.

[0113] In this case, the resin frame member 124 includes a frame-shaped first sheet 126 and a frame-shaped second sheet 128. An adhesive layer 130 is interposed between the first sheet 126 and the second sheet 128. The first sheet 126 and the second sheet 128 are bonded and stacked via the adhesive layer 130. Examples of the raw materials for the first sheet 126 and the second sheet 128 include the same resin materials as those for the resin frame member 24 of the first embodiment.

[0114] The outer dimensions of the second sheet 128 are larger than those of the first sheet 126. Therefore, a portion of the second sheet 128 protrudes further toward the MEA 122 than the inner peripheral end 132 of the first sheet 126. This portion is hereinafter referred to as "inner peripheral portion 134." Inner peripheral portion 134 has a first surface 134a facing the electrolyte membrane 26 and a second surface 134b facing the second electrode 30. The adhesive layer 130 is provided on the entire surface of the second sheet 128 facing the first sheet 126. Therefore, the adhesive layer 130 is also provided on the first surface 134a of the inner peripheral portion 134.

[0115] The outer peripheral overlapping portion 40 of the outer peripheral portion 26o of the electrolyte membrane 26 overlaps the first surface 134a of the inner peripheral portion 134 of the second sheet 128. Since the adhesive layer 130 is provided on the inner peripheral portion 134, the inner peripheral portion 134 and the outer peripheral overlapping portion 40 are bonded via the adhesive layer 130. The outer peripheral portion 30o of the second electrode 30 overlaps the second surface 134b of the inner peripheral portion 134 of the second sheet 128. In other words, the second electrode catalyst layer 36 of the second electrode 30 is in contact with the second surface 134b. Furthermore, the first sheet 126 does not abut the MEA 122.

[0116] In the second embodiment, the electrolyte membrane 26 is composed of a thin film of a solid polymer having a functional group. As a preferred specific example of a solid polymer having a functional group, perfluorosulfonic acid can be cited. Figure 13 The chemical structural formula of perfluorosulfonic acid is shown in FIG. In this case, the functional group is a sulfonic acid group (-SO3H). The sulfonic acid group is a hydrophilic group.

[0117] As in the first embodiment, the first electrode catalyst layer 32 and the second electrode catalyst layer 36 contain an ion conductive polymer binder that physically binds the porous carbon particles. As in the solid polymer of the electrolyte membrane 26, a preferred specific example of the ion conductive polymer binder is perfluorosulfonic acid (see Figure 13 ).

[0118] The second ion flow blocking portion 140 is provided in a square ring shape (annular shape) at the outer edge of the outer peripheral overlapping portion 40 of the electrolyte membrane 26. The third ion flow blocking portion 142 is provided in a square ring shape (annular shape) at the outer edge of the second electrode catalyst layer 36. The second ion flow blocking portion 140 and the third ion flow blocking portion 142 are described below.

[0119] The second ion flow blocking portion 140 is a first modified portion formed by chemically modifying the outer edge of the electrolyte membrane 26. In other words, the second ion flow blocking portion 140 is a chemical barrier. Specifically, when the raw material of the electrolyte membrane 26 is perfluorosulfonic acid, in the second ion flow blocking portion 140, cations other than iron ions or copper ions are chemically bonded to the sulfonic acid group. Preferred specific examples of cations include cesium ions (Cs + ), lead ions (Pb 2+ ), silver ions (Ag + ) or alkaline earth metal ions. The hydrophilicity of the sulfonic acid groups chemically bonded to these cations is reduced. Among them, alkaline earth metal ions are particularly preferred. This is because in this case, cations can be easily obtained at low cost. A preferred specific example of alkaline earth metal ions is magnesium ion (Mg 2+ ), calcium ions (Ca 2+ ), strontium ions (Sr 2+ ), barium ions (Ba 2+ ).

[0120] The third ion flow blocking portion 142 is a second modified portion formed by chemically modifying the ion conductive polymer contained in the outer edge portion of the second electrode catalyst layer 36. That is, the third ion flow blocking portion 142 is also a chemical barrier. Specifically, in the case where the raw material of the ion conductive polymer is perfluorosulfonic acid, in the third ion flow blocking portion 142, as described above, cations other than iron ions or copper ions are chemically bonded to the sulfonic acid group. Therefore, in the third ion flow blocking portion 142, the hydrophilicity is also reduced. A preferred specific example of the cation is the same as described above, which is cesium ion (Cs + ), lead ions (Pb 2+ ), silver ions (Ag + ), magnesium ions (Mg 2+ ), calcium ions (Ca 2+ ), strontium ions (Sr 2+ ), barium ions (Ba 2+ ).

[0121] The power generation cell 110 operates in the same manner as the power generation cell 12. The flow paths of the fuel gas, oxidant gas, and cooling medium are the same as those of the first embodiment (see Figure 1 ). Therefore, detailed description of the flow paths of the fuel gas, oxidant gas, and cooling medium will be omitted.

[0122] Next, a method for manufacturing the resin-framed MEA 120 according to the second embodiment will be described.

[0123] like Figure 14 As shown, the method for manufacturing the resin-framed MEA 120 according to the second embodiment includes a lamination step, a bonding step, and a stopper portion forming step.

[0124] In the lamination process (step S10) of the second embodiment, as Figure 15 As shown, the electrolyte membrane 26 is stacked on the first electrode 28. In this case, the first electrode 28 is provided on the first surface 26a of the electrolyte membrane 26. Then, the second electrode 30 is stacked on the second surface 26b of the electrolyte membrane 26. Alternatively, the first electrode 28 may be stacked on the first surface 26a of the electrolyte membrane 26 after the second electrode 30 is stacked on the second surface 26b of the electrolyte membrane 26. Thus, the MEA 122 is obtained.

[0125] On the other hand, the first sheet 126 and the second sheet 128 are bonded together via the adhesive layer 130. In this way, the resin frame member 124 is completed.

[0126] Then, if Figure 15As shown, the inner peripheral portion 134 of the second sheet 128 is overlapped with the outer peripheral overlapping portion 40 of the electrolyte membrane 26. At this time, the first surface 134a of the second sheet 128 faces the outer peripheral overlapping portion 40. Since the adhesive layer 130 is provided on the inner peripheral portion 134, the inner peripheral portion 134 and the outer peripheral overlapping portion 40 are bonded via the adhesive layer 130.

[0127] Then, the outer peripheral portion 30o of the second electrode 30 is overlapped on the second surface 134b of the inner peripheral portion 134 of the second sheet 128. As a result, the second electrode catalyst layer 36 of the second electrode 30 is in contact with the second surface 134b.

[0128] Next, the bonding process is performed (step S20). In the bonding process, the Figure 16 The hot pressing device 150 shown in FIG. The hot pressing device 150 includes a base 152 and a movable mold 154. The movable mold 154 can be displaced in a direction close to or away from the base 152.

[0129] MEA 122 is placed on base 152 with the inner circumference 134 of second sheet 128 sandwiched between first electrode 28 and second electrode 30. At this point, first electrode 28 faces downward, and second electrode 30 faces upward. Then, movable mold 154, heated to a predetermined temperature, is lowered toward base 152. This lowering sandwiches the outer circumference of MEA 122 and the inner circumference 134 of second sheet 128 between base 152 and movable mold 154. Consequently, pressure is applied to the outer circumference of MEA 122 and the inner circumference 134 of second sheet 128. As described above, since movable mold 154 is heated, heat is applied to the outer circumference of MEA 122 and the inner circumference 134 of second sheet 128.

[0130] In this manner, the outer periphery of MEA 122 and inner periphery 134 of second sheet 128 are hot pressed. As a result, outer periphery overlap 40 of electrolyte membrane 26 is bonded to inner periphery 134 of second sheet 128 via adhesive layer 130. Thus, MEA 122 and resin frame member 124 are bonded.

[0131] In the second embodiment, the blocking portion forming step (step S30 ) is then performed. Here, the case where the second ion flow blocking portion 140 as the first transformed portion and the third ion flow blocking portion 142 as the third transformed portion are formed is exemplified.

[0132] In the blocking portion forming process, Figure 17As shown, a solution 160 containing the above-mentioned cations is applied to the side of the outer edge of the peripheral overlapping portion 40 of the electrolyte membrane 26. The application is, for example, spraying. In this case, a spray of the solution 160 is sprayed onto the side of the outer edge of the peripheral overlapping portion 40 of the electrolyte membrane 26. A preferred specific example of a cation is the barium ion described above. A preferred specific example of the solution 160 containing barium ions is an aqueous solution of barium chloride (BaCl2). However, the solvent of the solution 160 containing barium ions is not limited to water. The barium salt as a source of barium ions is not limited to barium chloride. Instead, a solution containing cesium ions, lead ions, silver ions, magnesium ions, calcium ions or strontium ions may also be used.

[0133] The raw materials of the electrolyte membrane 26 are Figure 13 In the case of perfluorosulfonic acid shown in FIG. 1 , the electrolyte membrane 26 has a sulfonic acid group as a functional group. In the case of an alkaline earth metal ion as a cation, it is presumed that the ion replaces the H of the two sulfonic acid groups. + In this case, the distance between the two sulfonic acid groups is shortened. As a result, the electrolyte membrane 26 partially shrinks slightly. Furthermore, the aforementioned substitution reduces the hydrophilicity of the electrolyte membrane 26. As a result, a first degraded portion is formed in the electrolyte membrane 26. When barium ions are used, the hydrophilicity of the electrolyte membrane 26 is significantly reduced.

[0134] Solution 160 is applied to the entire side surface of the outer edge portion of the peripheral overlapping portion 40 of the electrolyte membrane 26. This forms a square ring-shaped first altered portion (second ion flow blocking portion 140) on the outer overlapping portion 40. Similarly, solution 160 is applied to the entire side surface of the outer edge portion of the first electrode 28. Furthermore, solution 160 may adhere to the first electrode 28. In this case, the ion conductive polymer serving as a binder contained in the first electrode catalyst layer 32 undergoes chemical degradation. As a result, an ion flow blocking portion serving as a chemical barrier is formed in the first electrode catalyst layer 32.

[0135] Similarly, the solution 160 containing the above-mentioned cations is applied to the side surface of the outer edge portion of the second electrode 30 (see Figure 17 ). The coating is, for example, spraying. A preferred specific example of the cation is the barium ion described above. Alternatively, a solution containing cesium ions, lead ions, silver ions, magnesium ions, calcium ions, or strontium ions may be used.

[0136] The second electrode catalyst layer 36 contains an ion conductive polymer binder. When the raw material of the ion conductive polymer binder is perfluorosulfonic acid, the cations are chemically bonded to the sulfonic acid groups in the same manner as described above. For example, two sulfonic acid groups H +The sulfonic acid groups are replaced by alkaline earth metal ions. In this case, the distance between the two sulfonic acid groups is shortened. As a result, the second electrode catalyst layer 36 partially shrinks slightly. Furthermore, the aforementioned substitution reduces the hydrophilicity of the second electrode catalyst layer 36. As a result, a second altered portion is formed in the second electrode catalyst layer 36. When barium ions are used, the hydrophilicity of the second electrode catalyst layer 36 is significantly reduced.

[0137] The solution 160 is applied to the entire side surface of the outer edge portion of the second electrode 30. As a result, a square ring-shaped second altered portion (third ion flow blocking portion 142) is formed on the second electrode catalyst layer 36.

[0138] Thus, a resin-framed MEA 120 is obtained, which includes the second ion blocking portion 140 and the third ion blocking portion 142. The second ion blocking portion 140 and the third ion blocking portion 142 are each in a square ring shape (annular shape). Based on this shape, the second ion blocking portion 140 and the third ion blocking portion 142 surround the power generation region 44 of the MEA 122.

[0139] The joining process and the blocking portion forming process may be performed in the reverse order. That is, the blocking portion forming process may be performed first and then the joining process.

[0140] When the fuel cell stack 14 including the power generation cell 110 is operated, water vapor is added to the fuel gas and the oxidant gas as in the first embodiment. When the metal components of the first separator member 16 and the second separator member 18 are dissolved into the water vapor contained in the reaction gas, iron ions (Fe 2+ ) or copper ions (Cu 2+ ) and other metal ions.

[0141] The second embodiment achieves the following effects.

[0142] A second ion flow blocking portion 140 is provided on the outer periphery of the outer peripheral overlapping portion 40 of the electrolyte membrane 26 . A third ion flow blocking portion 142 is provided on the outer periphery of the second electrode catalyst layer 36 .

[0143] The hydrophilicity of the second ion-blocking section 140 and the third ion-blocking section 142 is reduced. Consequently, the number of paths for water to flow through the second ion-blocking section 140 and the third ion-blocking section 142 is reduced. Consequently, iron ions, copper ions, and the like that have dissolved into water vapor are less likely to pass through the second ion-blocking section 140 and the third ion-blocking section 142.

[0144] Furthermore, the cations are firmly bonded to the sulfonic acid groups. Therefore, iron ions, copper ions, etc. are not easily displaced from the cations bonded to the sulfonic acid groups. Therefore, iron ions, copper ions, etc. are not easily moved along the sulfonic acid groups.

[0145] For the reasons described above, iron ions, copper ions, and the like are blocked by the second ion flow blocking portion 140 and the third ion flow blocking portion 142. Consequently, it is possible to prevent iron ions, copper ions, and the like from entering the central region 46 (particularly the power generation region 44 of the MEA 122) from the outer peripheral ends of the electrolyte membrane 26. This prevents the central region 46 of the electrolyte membrane 26 from being affected by the iron ions, copper ions, and the like and from deteriorating.

[0146] The second ion flow blocking portion 140 is a chemically altered portion of the electrolyte membrane 26. The third ion flow blocking portion 142 is a chemically altered portion of the ion conductive polymer contained in the second electrode catalyst layer 36. Providing an ion flow blocking portion as a physical barrier requires machining. However, since the second ion flow blocking portion 140 and the third ion flow blocking portion 142 are chemical barriers, machining is not required to provide the second ion flow blocking portion 140 and the third ion flow blocking portion 142.

[0147] To chemically alter the electrolyte membrane 26, for example, a solution 160 containing cations such as alkaline earth metal ions is applied to the electrolyte membrane 26. This facilitates the formation of the first altered portion (second ion flow blocking portion 140) and the second altered portion (third ion flow blocking portion 142).

[0148] In addition, if Figure 18 As in the resin-framed MEA 200 shown in FIG. 1 , both the first ion flow blocking portion 50 in the first embodiment and the second altered portion (third ion flow blocking portion 142 ) in the second embodiment may be provided.

[0149] As described above, this embodiment discloses a resin frame MEA (10, 120, 200) which is an MEA of a power generation cell (12, 110) for a fuel cell, comprising an MEA (22, 122) and a resin frame member (24, 124), wherein:

[0150] The MEA (22, 122) comprises an electrolyte membrane (26), a first electrode (28) disposed on a first surface (26a) of the electrolyte membrane, and a second electrode (30) disposed on a second surface (26b) of the electrolyte membrane;

[0151] The resin frame member (24, 124) is attached to the outer peripheral portion (22o, 122o) of the MEA in a manner protruding outward from the outer peripheral portion.

[0152] The electrolyte membrane has an outer peripheral overlapping portion (40) overlapping with the inner peripheral portion (24i, 134) of the resin frame member.

[0153] An ion flow blocking portion (50, 140) for blocking ion flow is provided on the outer peripheral overlapping portion.

[0154] The ion flow blocking portion is annular and surrounds the power generation area (44) of the MEA.

[0155] The ion flow blocking portion blocks iron, copper, and other ions at a location outside the power generation area of ​​the electrolyte membrane. This prevents these ions from entering the power generation area of ​​the MEA. This prevents the MEA from degrading due to the effects of these ions. In other words, the MEA is chemically protected.

[0156] A typical example of an ion flow blocking portion is a physical barrier. A specific example of a physical barrier is a convex portion. That is, in the resin-framed MEA disclosed in this embodiment, the outer peripheral portion of the MEA has a groove (42) that penetrates at least the outer peripheral overlapping portion of the electrolyte membrane in the thickness direction, and the ion flow blocking portion is a convex portion (50) that enters the groove.

[0157] The groove may also be formed so as to extend from the electrolyte membrane to the first electrode. Specifically, in the resin-framed MEA disclosed in this embodiment, the outer periphery of the first electrode overlaps the outer periphery of the electrolyte membrane, and the groove is formed between the outer periphery of the electrolyte membrane and the outer periphery of the first electrode. In this case, the ion flow blocking portion extends into the groove until it reaches the first electrode.

[0158] In the resin frame MEA disclosed in this embodiment, the convex portion forming the ion flow blocking portion is provided by an adhesive (54) that bonds the inner peripheral portion of the resin frame member and the outer peripheral overlapping portion of the electrolyte membrane.

[0159] When a portion of the adhesive is used as the ion-blocking portion, there is no need to apply a material for forming the convex portion separately from the adhesive to the electrolyte membrane.

[0160] Another typical example of the ion flow blocking portion is a chemical barrier. In this case, the outer peripheral overlapping portion of the electrolyte membrane is partially chemically altered. That is, in the resin-framed MEA disclosed in this embodiment, the ion flow blocking portion is a first altered portion (140) in an annular shape formed by chemically altering the outer peripheral overlapping portion of the electrolyte membrane.

[0161] A typical example of a raw material for the electrolyte membrane in a fuel cell is a solid polymer having functional groups. In this case, the electrolyte membrane can be chemically altered by chemically bonding a cation other than iron or copper ions to the functional groups. Specifically, in the resin-framed MEA disclosed in this embodiment, the raw material for the electrolyte membrane is a solid polymer having functional groups, and the first altered portion is formed by chemically bonding the functional groups to cations other than iron or copper ions.

[0162] A typical specific example of a raw material for the electrolyte membrane is a solid polymer having a sulfonic acid group (e.g., perfluorosulfonic acid). Furthermore, the cation is preferably a cesium ion, a lead ion, a silver ion, or an alkaline earth metal ion. That is, in the resin frame MEA disclosed in this embodiment, the functional group is a sulfonic acid group, and the cation is a cesium ion, a lead ion, a silver ion, or an alkaline earth metal ion.

[0163] In the resin frame MEA disclosed in this embodiment, the second electrode has an electrode catalyst layer (36), which is a layer containing an electrode catalyst and an ion conductive polymer having a functional group, and has a second modified portion (142) in an annular shape formed by chemically modifying the ion conductive polymer in the outer periphery of the electrode catalyst layer.

[0164] The ion-conductive polymer assists ion conduction in the electrode catalyst layer. The second modified portion is formed by chemically modifying the ion-conductive polymer. The ion-conductive polymer is typically included in the electrode catalyst layer as a binder.

[0165] The second modified portion blocks iron ions, copper ions, and the like. In other words, the second modified portion acts as a chemical barrier, preventing the flow of ions. In this case, the second modified portion inhibits the migration of iron ions, copper ions, and the like along the second electrode toward the electrolyte membrane. This effectively protects the electrolyte membrane.

[0166] To chemically modify the ion-conductive polymer, for example, cations other than iron or copper ions are chemically bonded to the functional groups of the ion-conductive polymer. Specifically, in the resin-frame MEA disclosed in this embodiment, the second modified portion is formed by chemically bonding the functional groups to cations other than iron or copper ions.

[0167] A typical example of an ion-conductive polymer is a solid polymer having a sulfonic acid group (e.g., perfluorosulfonic acid). In this case, the cation is preferably a cesium ion, a lead ion, a silver ion, or an alkaline earth metal ion. That is, in the resin frame MEA disclosed in this embodiment, the functional group is a sulfonic acid group, and the cation is a cesium ion, a lead ion, a silver ion, or an alkaline earth metal ion.

[0168] In addition, this embodiment discloses a method for manufacturing a resin-framed MEA (10, 120, 200), wherein the resin-framed MEA (10, 120, 200) is an MEA of a power generation cell (12, 110) for a fuel cell, the resin-framed MEA comprising an MEA (22, 122) and a resin frame member (24, 124), wherein:

[0169] The MEA (22, 122) comprises an electrolyte membrane (26), a first electrode (28) disposed on a first surface (26a) of the electrolyte membrane, and a second electrode (30) disposed on a second surface (26b) of the electrolyte membrane;

[0170] The resin frame member (24, 124) is attached to the outer peripheral portion (22o, 122o) of the MEA in a manner protruding outward from the outer peripheral portion.

[0171] The manufacturing method includes a lamination process, a bonding process and a blocking portion forming process, wherein:

[0172] In the lamination step, a laminate (80) is obtained by laminating the electrolyte membrane on the first electrode;

[0173] In the joining step, the inner peripheral portion (24i) of the resin frame member is overlapped with the outer peripheral portion of the electrolyte membrane on which the first electrode is stacked to form an outer peripheral overlapping portion (40) on the electrolyte membrane, and the inner peripheral portion of the resin frame member and the outer peripheral overlapping portion of the electrolyte membrane are joined;

[0174] In the blocking portion forming step, after the laminating step, an ion flow blocking portion (50, 140, 142) for blocking ion flow is provided on the outer peripheral overlapping portion of the electrolyte membrane.

[0175] The ion flow blocking portion is formed into a ring shape surrounding the power generation area (44) of the MEA.

[0176] In addition, there is also a situation where the blocking portion forming process is performed before the joining process. Conversely, there is also a situation where the joining process is performed before the blocking portion forming process. Therefore, the order of the joining process and the blocking portion forming process is not limited.

[0177] By performing the above steps, the resin-framed MEA having the ion flow blocking portion can be easily obtained.

[0178] In order to obtain a convex portion as a physical barrier as an ion flow blocking portion, a groove is formed in the outer peripheral overlapping portion of the electrolyte membrane. The convex portion that enters the groove is formed as the ion flow blocking portion. That is, in the manufacturing method of the MEA with a resin frame disclosed in this embodiment, the blocking portion forming process includes a groove forming process. In the groove forming process, an annular groove (42) is formed that at least penetrates the outer peripheral overlapping portion of the electrolyte membrane in the thickness direction. The bonding process is performed in a state where the material forming the ion flow blocking portion is filled in the groove, and the convex portion that enters the groove is obtained as the ion flow blocking portion.

[0179] The grooves can be formed, for example, by laser processing. Specifically, in the method for manufacturing a resin-framed MEA disclosed in this embodiment, in the groove forming step, the grooves are formed in the outer peripheral overlapped portion of the electrolyte membrane by laser processing. Laser processing facilitates groove formation.

[0180] In the method for manufacturing a resin-framed MEA disclosed in this embodiment, the ion flow blocking portion is produced using an adhesive (54) that bonds the inner peripheral portion of the resin frame member and the outer peripheral overlapping portion of the electrolyte membrane.

[0181] In this case, since part of the adhesive serves as the ion flow blocking portion, it is not necessary to apply a material for forming the convex portion to the electrolyte membrane.

[0182] In order to obtain an ion flow blocking portion serving as a chemical barrier, the outer peripheral overlapping portion of the electrolyte membrane is locally chemically modified. That is, in the method for manufacturing an MEA with a resin frame disclosed in this embodiment, the ion flow blocking portion is formed as a first modified portion (140) in an annular shape by locally chemically modifying the outer peripheral overlapping portion of the electrolyte membrane.

[0183] As described above, when the raw material of the electrolyte membrane in the fuel cell is a solid polymer having functional groups, cations other than iron ions or copper ions are chemically bonded to the functional groups. Specifically, in the method for manufacturing an MEA with a resin frame of this embodiment, the raw material of the electrolyte membrane is a solid polymer having functional groups, and the first modified portion is obtained by chemically bonding the functional groups to cations other than iron ions or copper ions.

[0184] When the raw material of the electrolyte membrane is a solid polymer having sulfonic acid groups (e.g., perfluorosulfonic acid), cesium ions, lead ions, silver ions, or alkaline earth metal ions are bonded to the sulfonic acid groups. Specifically, in the method for manufacturing an MEA with a resin frame disclosed in this embodiment, the functional groups are sulfonic acid groups, and the first altered portion is obtained by chemically bonding the sulfonic acid groups to the cesium ions, lead ions, silver ions, or alkaline earth metal ions.

[0185] The method for manufacturing a resin-frame MEA disclosed in this embodiment includes a step of applying the liquid (160) containing the cations to the electrolyte membrane.

[0186] This makes it easy to donate cations to the sulfonic acid groups. Therefore, the cations can be bonded to the sulfonic acid groups through simple operations. In other words, it is easier to chemically degrade the electrolyte membrane locally. Furthermore, a preferred example of a liquid containing barium ions is an aqueous solution of barium chloride.

[0187] In the manufacturing method of the MEA with a resin frame disclosed in this embodiment, the second electrode has an electrode catalyst layer (36), which is a layer containing an electrode catalyst and an ion conductive polymer having functional groups, and has a process of chemically bonding the functional groups of the ion conductive polymer in the outer periphery of the second electrode with cations other than iron ions or copper ions to obtain a second modified portion (142) with a ring shape.

[0188] The second modified portion forms an ion flow blocking portion on the second electrode, acting as a chemical barrier. Since the second modified portion also blocks iron or copper ions, it can suppress the migration of iron or copper ions along the second electrode toward the electrolyte membrane. This effectively protects the electrolyte membrane.

[0189] When the ion-conductive polymer is a polymer having sulfonic acid groups (e.g., perfluorosulfonic acid), cesium ions, lead ions, silver ions, or alkaline earth metal ions are bonded to the sulfonic acid groups. That is, in the method for manufacturing an MEA with a resin frame disclosed in this embodiment, the ion-conductive polymer has sulfonic acid groups as the functional groups, and the cesium ions, lead ions, silver ions, or alkaline earth metal ions are chemically bonded to the sulfonic acid groups to obtain the second transformed portion.

[0190] The method for manufacturing a resin-framed MEA disclosed in this embodiment includes a step of applying the liquid (160) containing the cations to the second electrode.

[0191] In this case, as described above, cations can also be easily provided to the sulfonic acid groups. Therefore, the cations can be bonded to the sulfonic acid groups through a simple operation. This makes it easier to chemically modify the local area of ​​the second electrode. A preferred specific example of the liquid used to chemically modify the local area of ​​the second electrode is, as described above, an aqueous solution of barium chloride.

[0192] Alternatively, both the first and second transformed portions can be formed. In this case, the step of forming the second transformed portion can be included in the step of forming the barrier portion. For example, a liquid containing cations can be applied to the outer overlapping portion of the electrolyte membrane, and a liquid containing cations can be applied to the outer periphery of the second electrode.

[0193] In addition, the present invention is not limited to the above-mentioned embodiment, and various structures can be adopted without departing from the scope of the present invention.

[0194] For example, in the first embodiment, a resin frame member 124 formed by joining two members may be used, similarly to the second embodiment. Conversely, in the second embodiment, a resin frame member 24 formed by one member may be used, similarly to the first embodiment.

Claims

1. A resin frame MEA (10, 120, 200), which is an MEA of a power generation cell (12, 110) for a fuel cell, characterized in that: An MEA (22, 122) and a resin frame member (24, 124) are provided, wherein: The MEA (22, 122) comprises an electrolyte membrane (26), a first electrode (28) disposed on a first surface (26a) of the electrolyte membrane, and a second electrode (30) disposed on a second surface (26b) of the electrolyte membrane; The resin frame member (24, 124) is attached to the outer peripheral portion (22o, 122o) of the MEA in a manner protruding outward from the outer peripheral portion. The electrolyte membrane has an outer peripheral overlapping portion (40) that overlaps with the inner peripheral portion (24i, 134) of the resin frame member and is sandwiched between the inner peripheral portion of the resin frame member and the outer peripheral portion of the first electrode. The outer peripheral portion of the MEA has a groove (42), and the groove (42) penetrates at least the outer peripheral overlapping portion in the thickness direction. An ion flow blocking portion (50, 140) is provided to block ion flow in such a manner that the entire area of ​​the groove is filled. The ion flow blocking portion is in an annular shape that continuously surrounds the outer peripheral side of the power generation area (44) of the MEA.

2. The resin-framed MEA according to claim 1, wherein: The ion flow blocking portion is a convex portion (50) that enters the groove.

3. The resin-framed MEA according to claim 1, wherein: The outer peripheral portion of the first electrode overlaps with the outer peripheral overlapping portion of the electrolyte membrane, The groove is formed in the outer peripheral overlapping portion of the electrolyte membrane and the outer peripheral portion of the first electrode.

4. The MEA with a resin frame according to claim 2, wherein: The convex portion forming the ion flow blocking portion is provided by an adhesive (54) that bonds the inner peripheral portion of the resin frame member and the outer peripheral overlapping portion of the electrolyte membrane to each other.

5. A method for manufacturing a resin-framed MEA (10, 120, 200), wherein the resin-framed MEA (10, 120, 200) is an MEA for a power generation cell (12, 110) for a fuel cell, characterized in that: The resin frame MEA includes an MEA (22, 122) and a resin frame member (24, 124), wherein: The MEA (22, 122) comprises an electrolyte membrane (26), a first electrode (28) disposed on a first surface (26a) of the electrolyte membrane, and a second electrode (30) disposed on a second surface (26b) of the electrolyte membrane; The resin frame member (24, 124) is attached to the outer peripheral portion (22o, 122o) of the MEA in a manner protruding outward from the outer peripheral portion. The manufacturing method includes a lamination process, a bonding process and a blocking portion forming process, wherein: In the lamination step, a laminate (80) is obtained by laminating the electrolyte membrane on the first electrode; In the joining step, the inner peripheral portion (24i) of the resin frame member is overlapped with the outer peripheral portion of the electrolyte membrane on which the first electrode is stacked to form an outer peripheral overlapping portion (40) on the electrolyte membrane, and the inner peripheral portion of the resin frame member and the outer peripheral overlapping portion of the electrolyte membrane are joined; In the blocking portion forming step, after the laminating step, an ion flow blocking portion (50, 140, 142) for blocking ion flow is provided on the outer peripheral overlapping portion of the electrolyte membrane. The blocking portion forming step includes a groove forming step, In the groove forming step, an annular groove (42) is formed that penetrates at least the outer peripheral overlapping portion of the electrolyte membrane in the thickness direction. The bonding step is performed in a state where the entire area of ​​the groove is filled with a material forming the ion flow blocking portion. The ion flow blocking portion is formed into a ring shape that continuously surrounds the outer peripheral side of the power generation area (44) of the MEA.

6. The method for manufacturing a resin-framed MEA according to claim 5, wherein: A convex portion entering the groove is obtained as the ion flow blocking portion.

7. The method for manufacturing a resin-framed MEA according to claim 6, wherein: In the groove forming step, the groove is formed in the outer peripheral overlapping portion of the electrolyte membrane by laser processing.

8. The method for manufacturing a MEA with a resin frame according to claim 5, wherein: The ion flow blocking portion is produced by using an adhesive (54) that bonds the inner peripheral portion of the resin frame member and the outer peripheral overlapping portion of the electrolyte membrane to each other.

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