JP2009301837A - Fuel cell, end sealing member and method of manufacturing end sealing member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To deter generation of gas leak with time, by preventing the fall of sealing pressure due to creeping. <P>SOLUTION: At outer edges parallel with gas flow channels of porous base materials 120a, 120b, 120c, 120d, end sealing members 140a, 140b, 140c, 140d are arranged so as gas of each channel not to leak to a counter electrode. The end sealing members 140a, 140b, 140c, 140d have end sealing members such as swollen graphite sheets formed with water-repellent treatment given, on surfaces other than those at sides of the porous base materials 120a, 120b, 120c, 120d. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a fuel cell, an end seal member thereof, and a manufacturing method of the end seal member, and in particular, an electrolyte layer holding an electrolyte is sandwiched between a fuel electrode catalyst layer and an air electrode catalyst layer, and fuel gas is contained in the fuel electrode catalyst layer. A unit cell in which a first porous substrate having a gas flow path is disposed, and a second porous substrate having a gas flow path for an oxidant gas is disposed in the air electrode catalyst layer, and a gas impermeable separator And a method of manufacturing the end seal member and the end seal member.

In recent years, fuel cells are expected to be widely used for various purposes because they can directly convert chemical energy of fuel into electrical energy and thus have high power generation efficiency and are environmentally friendly.
FIG. 5 is a schematic configuration diagram showing a state in which two unit cells of the fuel cell are stacked. In the fuel cell 200, ribbed porous base materials 220a and 220b having gas flow paths and electrode portions 230a and 230b constituting a counter electrode are sandwiched between separators 210a and 210b. An electrolyte layer (not shown) is formed between the electrode portions 230a and 230b. Similarly, porous base materials 220c and 220d and electrode portions 230c and 230d constituting a counter electrode are sandwiched between separators 210b and 210c. End seal members 240a, 240b, 240c, and 240d are arranged in the extended portions parallel to the gas flow paths of the porous base materials 220a, 220b, 220c, and 220d so that the respective gases do not leak to the counter electrode. Here, the end seal members 240a, 240b, 240c, and 240d indicate a pair of end seal members disposed with the porous base materials 220a, 220b, 220c, and 220d interposed therebetween, respectively.

  The end seal members 240a, 240b, 240c, and 240d are required to have gas impermeability and corrosion resistance to the electrolyte. Moreover, since it is necessary to ensure the height of the gas flow path, a thickness of about 2 mm is required. Furthermore, if a large amount of electrolyte is contained, there is a possibility that a problem such as electrolyte migration between the upper and lower cells may occur due to electrolyte leakage between the upper and lower cells at the end surfaces of the end seal members 240a, 240b, 240c, and 240d. For this reason, it was required that the electrolyte does not have a liquid junction at the end face. As the end seal members 240a, 240b, 240c, and 240d that satisfy these conditions, a conventional graphitized dense carbon material or a separator member is cut into the width of the end seal member to obtain a fluororesin film. The thing laminated | stacked through is used.

  Further, the porous base materials 220a and 220b, the electrode portions 230a and 230b, and the end seal members 240a and 240b that form the gas passages are stepped due to a dimensional error in manufacturing each material. For example, when the total height of the porous base material 220a and the electrode portion 230a is larger than the height of the end seal member 240a, the pressure applied to the end seal member 240a is weakened, the sealing performance is deteriorated, and gas leakage occurs. Cause. Further, when the height of the end seal member 240a is larger than the total height of the porous base material 220a and the electrode portion 230a, the contact resistance of the electrode portions 230a and 230b increases.

  With respect to this problem, a cushion member is inserted into the upper and lower surfaces of the end seal members 240a and 240b to reduce the dimensional error between the porous base materials 220a and 220b and the electrode portions 230a and 230b and the end seal members 240a and 240b. Absorbing methods are known.

Further, with respect to the above problem, there is also known a method for obtaining a desired sealing performance by using an expanded graphite sheet as an end seal member, optimizing its compressive strain rate and absorbing the above dimensional error (for example, , See Patent Document 1).
JP 2001-023654 A

  However, in the method using the cushion member and the method described in Patent Document 1, when the cushion member or the end seal member is used for a long time, the cushion member or the end seal is caused by a change in shape (creep) with time. There is a possibility that the pressure (seal pressure) applied to the member is lowered. And when a seal pressure falls, there exists a subject of becoming a cause of gas leakage.

  The present invention has been made in view of these points, and an object thereof is to provide a fuel cell that suppresses the occurrence of gas leakage over time, an end seal member thereof, and a method of manufacturing the end seal member. .

  An electrolyte layer holding an electrolyte is sandwiched between a fuel electrode catalyst layer and an air electrode catalyst layer, a first porous substrate having a fuel gas gas flow path is disposed in the fuel electrode catalyst layer, and oxidation is performed on the air electrode catalyst layer. A fuel cell is provided in which a unit cell in which a second porous substrate having a gas flow path for agent gas is disposed and a gas-impermeable separator are laminated. The fuel cell has a first end seal member and a second end seal member. The first end seal member is swellable at the ends of the first porous substrate on two opposite sides parallel to the gas flow path of the fuel gas formed on the first porous substrate. When the predetermined first end seal material is disposed, the surface of the first end seal material excluding the surface on the first porous substrate side is subjected to water repellent treatment. The second end seal member is provided with swellability at the end portions of the second porous substrate on the two opposite sides parallel to the gas flow path of the oxidant gas formed on the second porous substrate. When the predetermined second end seal material is disposed, the surface of the second end seal material excluding the surface on the second porous substrate side is subjected to water repellent treatment.

  According to such a fuel cell, the first end seal member has a surface excluding the surface that becomes the first porous substrate side when the predetermined first end seal member having swelling property is disposed. It is formed by a water repellent treatment. Then, the first end seal member is disposed at the ends of the first porous substrate on the two opposite sides parallel to the gas flow path formed in the first porous substrate. Further, the second end seal member is formed by performing water repellent treatment on the surface excluding the surface which becomes the second porous substrate side when the predetermined second end seal member having swelling property is disposed. Is done. And the 2nd edge part seal member is arrange | positioned at the edge part of the 2nd porous base material of two opposing sides parallel to the gas flow path formed in the 2nd porous base material.

  Further, in order to solve the above-described problem, an end seal member disposed in the fuel cell, except for a surface on which the predetermined end seal member having swelling property becomes the porous substrate side when disposed An end seal member formed by subjecting the surface to a water repellency treatment is provided.

  Furthermore, in order to solve the above-mentioned problem, in the manufacturing method of the above-mentioned end seal member, the surface excluding the surface which becomes the porous substrate side when the predetermined end seal material having swelling property is disposed, A method for manufacturing an end seal member is provided.

  According to the fuel cell, the end seal member thereof, and the manufacturing method of the end seal member, the end seal material having swelling property is removed from the surface excluding the surface that becomes the porous substrate side when the fuel cell is disposed. Water repellent treatment is applied. If it does in this way, an edge part sealing material will swell including the electrolyte hold | maintained at an electrolyte layer, a fuel electrode catalyst layer, or a porous base material. Thereby, the fall of the seal pressure by creep can be suppressed and generation | occurrence | production of the gas leakage with time can be suppressed.

Hereinafter, the present embodiment will be described in detail with reference to the drawings.
1A and 1B are views showing a single end seal member of a fuel cell according to the present embodiment. FIG. 1A is a perspective view, and FIG. 1B is a side view of one end with respect to the longitudinal direction. The end seal member 140 is subjected to water repellent treatment by the end seal member 141 being covered with the fluororesin film 142. The end seal member 140 has a rectangular parallelepiped shape. The end seal member 140 has an inner surface 143, an outer surface 144, an upper surface 145, and a lower surface 146 with respect to the direction in which the end seal member 140 is disposed in the fuel cell.

  The end seal material 141 is represented by a dotted line in FIG. 1 and is formed of a predetermined end seal material having swelling properties including an expanded graphite sheet. In FIG. 1, there is a gap between the end seal material 141 and the fluororesin film 142 for the sake of explanation, but in actuality it is in close contact. In addition to the expanded graphite sheet, for example, a porous carbon plate, a fired carbon plate, or the like can be used as the end seal material 141.

  The fluororesin film 142 covers the end seal material 141 except for one surface (inner surface 143) in the longitudinal direction. Examples of the fluororesin include, for example, tetrafluoroethylene-hexafluoropropylene copolymer resin (FEP: Fluorinated Ethylene Propylene copolymer, melting point: 250 to 280 ° C), tetrafluoroethylene resin (PTFE: Poly Tetra Fluoro Ethylene, melting point: 327 ° C). ), Fluorinated alkyloxyethylene resin (PFA: Polytetrafluoroethylene-perfluoroalkenyl vinyl ether copolymer, melting point: 300 to 310 ° C.) and fluorinated ethylene propylene resin (TFP: Tetra Fluoro Propanol, melting point: 290 to 300 ° C.), etc. Can be used.

  The inner side surface 143 is a surface that is not covered with the fluororesin film 142 of the end seal member 140. The inner side surface 143 exposes the surface of the end seal material 141. The end seal member 140 is disposed in the fuel cell so that the inner side surface 143 faces the porous substrate side (inner side) (described in detail in FIG. 2).

The outer side surface 144 is a surface that is parallel to and faces the inner side surface 143. The outer side surface 144 is covered with the fluororesin film 142.
The upper surface 145 is a surface perpendicular to the inner side surface 143 and the outer side surface 144. The upper surface 145 is covered with the fluororesin film 142.

The lower surface 146 is a surface parallel to and opposed to the upper surface 145. The lower surface 146 is covered with the fluororesin film 142.
Note that both end surfaces of the end sealant 141 in the longitudinal direction are also covered with the fluororesin film 142.

In this manner, the inner side surface 143 of the end seal member 140 is not covered with the fluororesin film 142, and the end seal member 141 includes a liquid such as an electrolyte.
As a result, the end seal material 141 swells as appropriate, so that a decrease in the seal pressure due to creep can be prevented, and the occurrence of gas leak over time can be suppressed.

  Further, by covering the outer surface 144, the upper surface 145, the lower surface 146 and both end surfaces in the longitudinal direction with the fluororesin film 142, a water repellency effect can be obtained. Thereby, even if the end seal material 141 includes an electrolyte, the electrolyte can be prevented from leaking from the outer surface 144, the upper surface 145, the lower surface 146, both end surfaces in the longitudinal direction, and the like. Prevention of electrolyte leakage also has the effect of preventing liquid junctions between fuel cell cells.

  Note that the end seal material 141 does not need to expose the entire inner surface 143 as long as it can contain an electrolyte. For example, a part of the inner surface 143 may be covered with the fluororesin film 142. .

Hereinafter, the present embodiment will be described in detail with reference to the drawings.
FIG. 2 is a diagram showing a state in which two unit cells of the fuel cell according to the present embodiment are stacked. The fuel cell 100 shows a state in which a unit cell formed between the separator 110a and the separator 110b and a unit cell formed between the separator 110b and the separator 110c are stacked in two layers.

  The separators 110a, 110b, and 110c satisfy gas impermeability and corrosion resistance to the electrolyte. The separators 110a, 110b, and 110c are formed by, for example, impregnating a paper made of cellulose fiber with a thermosetting resin, drying, laminating and pressing, and further firing.

  The unit cell sandwiched between the separators 110a and 110b has an electrode portion 130a (fuel electrode) and an electrode portion 130b (air electrode) having a catalyst layer disposed with an electrolyte layer (not shown) interposed therebetween. Further, the unit cell includes a ribbed porous substrate that forms an oxidant gas or air flow path (hereinafter referred to as an air flow path) that is disposed with the electrolyte layer, the electrode part 130a, and the electrode part 130b interposed therebetween. It has material 120a, 120b. A layer including the porous substrate 120a and the electrode part 130a is referred to as a fuel electrode catalyst layer. The layer including the porous substrate 120b and the electrode part 130b is referred to as an air electrode catalyst layer. As a material of the porous base materials 120a and 120b, for example, porous carbon can be used. In the example of the fuel cell 100, the fuel gas channel and the air channel are overlapped so as to be orthogonal to each other.

  Similarly, with respect to the unit cells sandwiched between the separators 110b and 110c, the porous base material 120c and the electrode part 130c, and the porous base material 120d and the electrode part 130d are arranged on both sides of the electrolyte layer.

  In the electrolyte layer, for example, phosphoric acid is held as an electrolyte. Further, the porous base materials 120a, 120b, 120c, and 120d and the electrode portions 130a, 130b, 130c, and 130d are also impregnated and held with the phosphoric acid solution so that the phosphoric acid used as the electrolyte in the electrolyte layer is not insufficient. Thereby, it is possible to continue supplying phosphoric acid as an electrolyte to the electrolyte layer.

  End seal members 140a, 140b, 140c, and 140d are disposed on the outer edge portions of the porous base materials 120a, 120b, 120c, and 120d that are parallel to the gas flow paths so that the respective gases do not leak to the counter electrode.

  The end seal members 140a, 140b, 140c, and 140d are formed in the same manner as the end seal member 140 shown in FIG. That is, the end seal members 140a, 140b, 140c, and 140d are formed by coating the surface of the end seal material such as an expanded graphite sheet, excluding the surface on the porous substrate side, with the fluororesin. Here, the end seal members 140a, 140b, 140c, and 140d indicate a pair of end seal members disposed with the porous base materials 120a, 120b, 120c, and 120d interposed therebetween, respectively.

  Further, a cushion member 150a that absorbs manufacturing errors of the porous base material 120a, the electrode portion 130a, and the end seal member 140a is inserted into the lower surface of the end seal member 140a. Here, the cushion members 150a and 150b indicate a pair of cushion members disposed with the porous base materials 120a and 120c interposed therebetween, respectively.

  The cushion member 150a also absorbs manufacturing errors of the porous base material 120b, the electrode portion 130b, and the end seal member 140b. Similarly, the cushion member 150b absorbs manufacturing errors of the porous base material 120c and the electrode part 130c and the end seal member 140c and manufacturing errors of the porous base material 120d and the electrode part 130d and the end seal member 140d. As the cushion members 150a and 150b, the same material as the end seal material 141 can be used. As a material of the cushion members 150a and 150b, for example, foamed PTFE is used.

  In the fuel cell 100 having such a configuration, the end seal members 140a, 140b, 140c, and 140d and the cushion members 150a and 150b are held by the separators 110a, 110b, and 110c at an appropriate seal pressure that does not cause gas leakage. . However, when the fuel cell 100 is used for a long time, the seal pressure decreases due to the creep of the end seal members 140a, 140b, 140c, 140d and the cushion members 150a, 150b, causing gas leakage.

  3A and 3B are partially enlarged views of the fuel cell, in which FIG. 3A shows a state after use, and FIG. 3B shows a state after long-time use. FIG. 3 is an enlarged view of the portion indicated by the symbol X in FIG. 2 as viewed from the depth direction of the fuel cell 100. In addition to the configuration shown in FIG. 2, an electrolyte layer 160a is further illustrated. At the start of use of the fuel cell 100, the end seal members 140a and 140b and the cushion member 150a are held at an appropriate seal pressure that does not cause gas leakage by the separators 110a and 110b, as shown in FIG. However, as shown in (B), after a long period of use, the end seal members 140a and 140b and the cushion member 150a undergo shape changes due to creep (thickness reduction in the seal pressure direction), and the seal pressure decreases.

FIG. 3 schematically shows the thickness reduction due to creep so that it can be easily understood.
In contrast, in the fuel cell 100, the surfaces of the end seal members 140a, 140b, 140c, 140d on the porous base materials 120a, 120b, 120c, 120d side (inner side) are not covered with the fluororesin film. . That is, the end seal material used for the end seal members 140a, 140b, 140c, and 140d includes the electrolyte held on the porous base materials 120a, 120b, 120c, and 120d, and can swell.

  4A and 4B are partially enlarged views of the fuel cell, where FIG. 4A shows the end seal member impregnated with electrolyte, and FIG. 4B shows the end seal member after swelling. The fuel cell 100 swells with electrolyte as much as the thickness of the end seal members 140a and 140b and the cushion member 150a in the seal pressure direction decreases as shown in FIG. Then, as shown in (B), the decrease in the seal pressure due to the decrease in thickness is compensated to maintain an appropriate seal pressure that does not cause gas leakage.

  Thus, the end seal members 140a, 140b, 140c, and 140d of the fuel cell 100 swell by the thickness reduction due to creep of the end seal members 140a, 140b, 140c, and 140d and the cushion members 150a and 150b. Prevents a decrease in sealing pressure. Thereby, generation | occurrence | production of the gas leakage of the fuel cell 100 with time can be suppressed.

  Further, the end seal members 140a, 140b, 140c, and 140d other than the surface on the porous base material side are covered with a fluororesin film and have a water repellency effect. For this reason, even if the end seal material 141 contains an electrolyte, it is possible to prevent the electrolyte from leaking to the outer side surface of the end seal members 140a, 140b, 140c, 140d other than the surface on the porous substrate side. The prevention of electrolyte leakage also has an effect of preventing liquid junction between cells of the fuel cell 100. In this manner, the end seal members 140 a, 140 b, 140 c, and 140 d have gas impermeability and electrolyte non-leakage that are desired for use in the fuel cell 100.

Next, a specific example of a method for manufacturing such an end seal member 140 will be described.
(Production Method Example 1)
First, a glassy carbon plate (SG-3, thickness 0.6 mm) manufactured by Showa Denko KK is cut into 130 × 130 mm to obtain a separator. Then, an expanded graphite sheet (PF250, thickness 2.5 mm, bulk density 0.65 g / cm ³ ) manufactured by Toyo Tanso Co., Ltd. is cut into 18 × 130 mm to obtain an end seal material. Further, a 50 μm thick DuPont FEP (melting point: 250 to 280 ° C.) sheet cut to the same size as the end seal material is inserted between the separator and the end seal material, and 1.0 kg at a temperature of about 290 ° C. The separator and the end seal material are integrated by heat sealing under a pressure holding time of 10 minutes by applying a pressure of / cm ² . Then, the FEP sheet is heated at a temperature of about 290 ° C. and a pressure of 1.0 kg / cm ² on the surface of the outer surface excluding the surface on the porous substrate side of the end seal material, and the pressure is maintained for 10 minutes. The end seal member is formed by fusing.

(Production Method Example 2)
First, as in Production Method Example 1, an expanded graphite sheet (PF250, thickness 2.5 mm, bulk density 0.65 g / cm ³ ) manufactured by Toyo Tanso Co., Ltd. was cut into 18 × 130 mm, To do. Then, the end seal material is dipped in advance in “Teflon (registered trademark) 120J”, which is an FEP dispersion manufactured by Mitsui Fluorochemical, and fired in an electric furnace at 290 ° C. for 1 hour to perform water repellent treatment. At that time, the water-repellent treatment is not performed on the surface of the end seal material on the porous substrate side. For this purpose, for example, a jig is prepared for adjusting the liquid surface height at which the end sealing material is immersed in the Teflon liquid so that the surface of the end sealing material on the porous substrate side does not come into contact with the Teflon liquid. Then, an end seal member is formed on the surface of the porous substrate so that the water repellent treatment is not easily performed by installing an end seal material on this jig and dipping it in a Teflon solution. Can do.

After that, an end seal member is placed on the separator, and a pressure of 1.0 kg / cm ² is applied at about 290 ° C. and heat fusion is performed for 10 minutes under a pressure holding time, so that the separator and the end seal member are integrated. Turn into.

  In addition to FEP, for example, PTFE, PFA, TFP, and the like can be used as the fluororesin used in Production Method Examples 1 and 2. These are used, for example, in the form of a sheet having a thickness of 50 μm or a dispersion.

The fuel cell manufactured using the end seal member manufactured using the above method has a gas leak amount of 0.1 ml / min or less by differential pressure of 300 mmAq through the end seal member. It was. Further, there was no increase in leakage even after 2000 hours of operation at a current density of 300 mA / cm ² , and no increase in gas leakage due to creep of the end seal member or cushion member was observed. Further, as a result of the disassembly investigation after the operation, neither the end seal member corrosion nor the electrolyte liquid junction on the end seal member surface occurred. That is, it was confirmed that a fuel cell provided with a favorable end seal member was obtained.

  In the present embodiment, the configuration in which the cushion member is used for the fuel cell has been described as an example. However, the cushion member is inserted as necessary in order to obtain an appropriate sealing effect by the end seal member. For this reason, when an appropriate sealing effect can be obtained only by the end seal member, it is not necessary to use a cushion member. Even when the cushion member is not used, the end seal member of the present embodiment can be applied.

Moreover, in this Embodiment, although the edge part sealing member was illustrated as a rectangular parallelepiped shape, you may form in another pillar according to the design of a fuel cell.
Further, conventionally, in order to obtain an end seal member having a desired sealing performance, for example, it has been necessary to manage the properties such as the bulk density of the expanded graphite sheet used as the end seal material so as to be optimized. On the other hand, since the end seal member of the present invention does not require such management, it is not necessary to prepare various end seal materials for each property such as bulk density. For this reason, there is also an effect that it is possible to reduce the man-hours and inventory of parts.

It is the figure which showed the edge part sealing member single-piece | unit of the fuel cell of this Embodiment, Comprising: (A) is a perspective view, (B) is a side view of the one-side end with respect to a longitudinal direction. It is the figure which showed the state which laminated | stacked two unit cells of the fuel cell of this Embodiment. It is a partially enlarged view of the fuel cell, (A) shows the state after the start of use, and (B) shows the state after long-time use. It is a partial enlarged view of a fuel cell, (A) impregnates the end seal member with electrolyte, and (B) shows the end seal member after swelling. It is the schematic block diagram which showed the state which laminated | stacked two unit cells of the fuel cell.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Fuel cell 110a, 110b, 110c Separator 120a, 120b, 120c, 120d Porous base material 130a, 130b, 130c, 130d Electrode part 140, 140a, 140b, 140c, 140d End part sealing member 141 End part sealing material 142 Fluoro resin Membrane 143 Inner side surface 144 Outer side surface 145 Upper surface 146 Lower surface 150a, 150b Cushion member 160a Electrolyte layer

Claims (12)

An electrolyte layer holding an electrolyte is sandwiched between a fuel electrode catalyst layer and an air electrode catalyst layer, a first porous substrate having a gas flow path for fuel gas is disposed in the fuel electrode catalyst layer, and the air electrode catalyst layer In a fuel cell in which a unit cell in which a second porous substrate having a gas flow path for an oxidant gas is disposed and a gas impermeable separator are laminated,
A predetermined first end having swellability at two end portions of the first porous substrate parallel to the gas flow path of the fuel gas formed on the first porous substrate. A first end seal formed by performing a water repellent treatment on the surface of the first end seal member except the surface on the first porous substrate side when the part seal member is disposed. Members,
A predetermined second having swellability is formed at the ends of the second porous substrate on two opposite sides parallel to the gas flow path of the oxidant gas formed on the second porous substrate. A second end portion formed by subjecting the surface of the second end seal material to a surface excluding the surface on the second porous substrate side to be water-repellent when the end seal material is disposed. A sealing member;
A fuel cell comprising:   2. The fuel cell according to claim 1, wherein the first end seal material and the second end seal material are expanded graphite sheets.   2. The fuel cell according to claim 1, wherein the water-repellent treatment is performed by covering surfaces of the first end seal material and the second end seal material with a fluororesin material. 3.   The fuel cell according to claim 1, further comprising a cushion member disposed on an upper surface or a lower surface of the first end seal member or the second end seal member. An electrolyte layer holding an electrolyte is sandwiched between a fuel electrode catalyst layer and an air electrode catalyst layer, a first porous substrate having a gas flow path for fuel gas is disposed in the fuel electrode catalyst layer, and the air electrode catalyst layer Formed on the first porous substrate of the fuel cell in which a unit cell having a second porous substrate having an oxidant gas flow path and a gas impermeable separator are laminated. Ends of the first porous substrate on two opposite sides parallel to the gas flow path of the fuel gas, and parallel to the gas flow path of the oxidant gas formed on the second porous substrate. In the end seal member disposed on the two opposite sides of the second porous substrate,
An end seal member, wherein a predetermined end seal material having swelling property is formed by performing water-repellent treatment on a surface excluding a surface which becomes the porous substrate side during the disposition.   The end seal member according to claim 5, wherein the end seal material is an expanded graphite sheet.   6. The end seal member according to claim 5, wherein the water-repellent treatment is performed by coating with a fluororesin material. An electrolyte layer holding an electrolyte is sandwiched between a fuel electrode catalyst layer and an air electrode catalyst layer, a first porous substrate having a gas flow path for fuel gas is disposed in the fuel electrode catalyst layer, and the air electrode catalyst layer Formed on the first porous substrate of the fuel cell in which a unit cell having a second porous substrate having an oxidant gas flow path and a gas impermeable separator are laminated. Ends of the first porous substrate on two opposite sides parallel to the gas flow path of the fuel gas, and parallel to the gas flow path of the oxidant gas formed on the second porous substrate. In the manufacturing method of the end seal member disposed at the end of the second porous substrate on two opposite sides,
A method for producing an end seal member, comprising: a step in which a predetermined end seal material having swelling property performs a water repellent treatment on a surface excluding a surface which becomes the porous substrate side at the time of the arrangement. .   The method for manufacturing an end seal member according to claim 8, wherein the end seal member is an expanded graphite sheet.   9. The method for manufacturing an end seal member according to claim 8, wherein the water repellency treatment is performed by coating with a fluororesin material. The fluororesin material is formed in a sheet shape,
The method for producing an end seal member according to claim 10, wherein the water-repellent treatment is performed by heat-sealing the sheet-like fluororesin material to the end seal material. The fluororesin material is in a liquid state,
The water-repellent treatment is performed by immersing the liquid sealant in the liquid fluororesin material so that the surface on the porous substrate side does not touch the fluororesin material when the end sealant is disposed, and then the end portion The method of manufacturing an end seal member according to claim 10, wherein the fluororesin material adhering to the seal material is thermally fused and coated on the end seal material.

Images