JP2017220362A - Method for manufacturing fuel cell separator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress a power-generating body from being damaged by a separator.SOLUTION: A method for manufacturing a separator according to the present invention comprises the steps of applying carbon black to each surface of a metal separator material including titanium as a primary component and then, performing thermal treatment on the separator material, thereby forming a mixture layer including the carbon black and an oxide of metal included in the separator material on each surface of the separator material and an excess carbon layer including carbon black remaining on the mixture layer. The method further comprises: a removing step of removing the excess carbon layer formed on the second face while supporting the first face of the surfaces of the separator material and then, removing the excess carbon layer formed on the first face while supporting the second face with the excess carbon layer removed therefrom after the thermal treatment step; and a press work step of performing a press work on the separator material using the second face as a face to form a reactive gas flow path for supplying a reactive gas to a power-generating body after the removing step.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a method for manufacturing a fuel cell separator.

  Generally, a fuel cell has a fuel cell stack in which a plurality of single cells are stacked. Each single cell is configured by sandwiching a membrane electrode assembly between two separators, as described in Patent Document 1, for example. On one surface of the separator, a reaction gas channel for flowing a reaction gas in the single cell is formed, and on the other surface, a cooling medium channel for flowing a cooling medium in the single cell is formed. . In addition, a reaction gas manifold opening that functions as an inlet and an outlet for the reaction gas and a cooling medium manifold opening that functions as an inlet and an outlet for the cooling medium flow path are formed at the peripheral edge of the separator. Such a separator can be formed, for example, by pressing a metal separator material.

Japanese Patent Laying-Open No. 2015-149265

  Here, the separator is preferably excellent in conductivity and conductivity durability. “Conductive durability” means that high conductivity is maintained for a long time even in a high temperature / acid atmosphere inside the fuel cell. Therefore, the inventor performs a surface treatment on the separator material by using a new surface treatment method that enables a state in which both conductivity and conductivity durability are compatible, and presses the separator material that has been subjected to the surface treatment. The manufacturing method was adopted. However, it has been found that this surface treatment method may cause burrs and other irregularities on the surface of the separator after press working. Then, it was found that when a single cell was configured by sandwiching a membrane electrode assembly using a separator with such irregularities, the membrane electrode assembly could be damaged by the irregularities on the surface of the separator. .

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms.

(1) According to one form of this invention, the manufacturing method of the separator for pinching a power generation body and forming the cell of a fuel cell is provided. The separator manufacturing method includes: (a) a coating process in which carbon black is applied to both surfaces of a metal separator material containing titanium as a main component; and (b) the separator material after the coating process. Is formed of a mixed layer containing the carbon black and an oxide of a metal contained in the separator material on both surfaces of the separator material, and the carbon black remaining on the mixed layer. A surplus carbon layer, and (c) the surplus formed on the second surface by supporting the first surface of the surfaces on both sides of the separator material after the heat treatment step. A first removal step of removing the carbon layer; and (d) after the first removal step, the second surface from which the excess carbon layer has been removed is supported to be formed on the first surface. Before A second removal step for removing the surplus carbon layer; and (e) a surface that forms a reaction gas flow path for supplying a reaction gas to the power generator after the second removal step. And a pressing process for pressing the separator material.
In the separator manufacturing method of this embodiment, since the surplus carbon layer is present on the second surface supported in the first removal step, when the surplus carbon layer is removed in the second removal step, There is little possibility of scratches in the mixed layer. In contrast, since the first surface supported in the second removal step is after the excess carbon layer is removed in the first removal step, there is a possibility that scratches may occur on the surface of the mixed layer. high. There is a possibility that a sharp uneven shape such as a burr may occur at a place where a scratch is generated in the press working process. On the other hand, in the press working step in the manufacturing method of the above embodiment, the separator material is pressed with the second surface as a surface that forms a reaction gas flow path for supplying the reaction gas to the power generator. When the fuel cell is formed using the manufactured separator, it is possible to prevent the power generator from being damaged by a scratch generated in the separator.

  The present invention can be realized in various forms, for example, in the form of not only a separator manufacturing method for forming a fuel cell, but also a fuel cell manufacturing method. .

It is a perspective view which shows schematic structure of the fuel cell stack to which the separator for fuel cells in this invention is applied. It is the schematic plan view which looked at the anode side separator obtained with the manufacturing method of this invention from the opposite side to the MEA plate. It is a flowchart which shows the manufacturing method of an anode side separator. It is explanatory drawing which shows the example of the surface treatment apparatus which performs the coating process and heat treatment process as a surface treatment process. It is explanatory drawing which shows the example of the surplus carbon removal apparatus which performs the 1st and 2nd removal process as a surplus carbon removal process. It is explanatory drawing which shows the example of the press work apparatus which performs a press work process. It is explanatory drawing which shows the manufacturing method of a single cell. It is sectional drawing which expands and shows a part corresponding to the electric power generation part of the MEA plate in a single cell.

A. Configuration of fuel cell stack and separator:
FIG. 1 is a perspective view showing a schematic configuration of a fuel cell stack 100 to which fuel cell separators 40 and 50 according to the present invention are applied. The fuel cell stack 100 is formed by stacking a plurality of single cells 140 in the X-axis direction shown in FIG. In the figure, the X axis and the Z axis are parallel to the horizontal plane, the + Y direction indicates a vertically upward direction, and the −Y direction indicates a vertically downward direction. The unit cell 140 includes a membrane electrode assembly (hereinafter referred to as “MEA” (Membrane-Electrode Assembly)) plate 30 and two fuel cell separators disposed between the MEA plates 30, that is, an anode-side separator 50. And a cathode-side separator 40. The MEA plate 30 includes a power generation unit 32 and a support frame 31 disposed so as to surround the power generation unit 32. The power generation unit 32 includes an MEA disposed along the stacking direction (X-axis direction) of the single cells 140 and two gas diffusion layers sandwiching the MEA. In addition, you may comprise the electric power generation part 32 by one membrane electrode gas diffusion layer assembly (MEGA). The fuel cell stack 100 is a so-called polymer electrolyte fuel cell, and constitutes a fuel cell system together with a reaction gas (oxidant gas and fuel gas) supply unit, a cooling medium supply unit, and the like. Such a fuel cell system is mounted on a vehicle or the like and used as a system for supplying driving power, for example. More specifically, the power generation unit 32 corresponds to the “power generation body” than the MEA plate 30.

  FIG. 2 is a schematic plan view of the anode separator 50 obtained by the manufacturing method of the present invention as viewed from the side opposite to the MEA plate 30. A fuel gas inlet manifold opening 62, a coolant outlet manifold opening 84, and an oxidant gas inlet manifold opening 72 are arranged in this order from top to bottom at one end edge in the longitudinal direction of the anode separator 50. ing. On the other hand, an oxidant gas outlet manifold opening 74, a cooling medium inlet manifold opening 82, and a fuel gas outlet manifold opening 64 are provided in order from the top to the bottom at the other end edge. . The fuel gas inlet manifold opening 62 and the fuel gas outlet manifold opening 64, the oxidant gas inlet manifold opening 72 and the oxidant gas outlet manifold opening 74, the cooling medium inlet manifold opening 82 and the cooling medium outlet manifold opening 84 are anode side separators. 50 are arranged so as to face each other at the outer edge portions on both sides in the longitudinal direction. Each manifold opening 62, 64, 72, 74, 82, 84 is substantially rectangular.

  A cooling medium passage groove 54 is formed between the cooling medium inlet manifold opening 82 and the cooling medium outlet manifold opening 84 on the surface of the anode side separator 50 opposite to the MEA plate 30. In the state where the plurality of single cells 140 are stacked, the cooling medium inlet manifold opening 82, the cooling medium passage groove 54, and the cooling medium outlet manifold opening 84 communicate with each other to form the cooling medium passage surface 200. A fuel gas passage groove (not shown) for supplying fuel gas (reactive gas) to the anode side portion of the MEA of the power generation unit 32 is formed on the MEA plate 30 side of the anode side separator 50. The gas inlet manifold opening 62, the fuel gas passage groove, and the fuel gas outlet manifold opening 64 communicate with each other to form a fuel gas passage surface.

  In FIG. 2, a seal member 80 is formed so as to run along each outer edge of each of the reaction gas manifold openings 62, 64, 72, 74 and the cooling medium flow path surface 200, and is disposed on the anode side separator 50. The seal member 80 has a function of contacting the surface of the cathode separator 40 of another adjacent unit cell 140 when the plurality of unit cells 140 are stacked, and sealing between the two unit cells 140. Specifically, in the seal member 80, the portions surrounding the manifold openings 62 and 64 are for suppressing fuel gas leakage, and the portions surrounding the manifold openings 72 and 74 are for suppressing oxidant gas leakage. The portion surrounding the cooling medium flow path surface 200 is for suppressing leakage of the cooling medium.

  Although not shown, the cathode side separator 40 obtained by the manufacturing method of the present invention is also provided with manifold openings for fuel gas, oxidant gas, and cooling medium, similarly to the anode side separator 50. Further, an oxidant gas flow channel for supplying an oxidant gas (reactive gas) to the cathode side portion of the MEA of the power generation unit 32 is formed on the surface of the cathode side separator 40 on the MEA plate 30 side. A cooling medium flow channel is formed on the surface opposite to the MEA plate 30.

B. Manufacturing method of fuel cell separator:
FIG. 3 is a flowchart showing a method for manufacturing the anode-side separator 50. In this separator manufacturing method, as will be described below, as a surface treatment process for the separator material, a coating process T1 for applying carbon to the separator material and a heat treatment process T2 are performed, and surplus carbon after the surface treatment is performed. As the removal step, the first removal step T3 and the second removal step T4 are executed, and the press working step T5 is executed to form the anode-side separator 50.

  FIG. 4 is an explanatory diagram showing an example of a surface treatment apparatus 500 that performs a coating process T1 (FIG. 3) and a heat treatment process T2 (FIG. 3) as a surface treatment process. The surface treatment apparatus 500 includes a supply roll 510, a coating unit 520, a heat treatment unit 530, and a take-up roll 540. A roll separator material TS is set on the supply roll 510. As a material for the separator material TS, a metal plate such as SUS (iron, chromium, nickel), titanium, titanium alloy or the like can be used, and it is particularly preferable to use a metal plate mainly composed of titanium. In the present embodiment, a titanium plate material is employed. Although a titanium oxide film is usually attached to the surface of the roll-shaped separator material TS set on the supply roll 510, it may be omitted in the description of the surface treatment. Omitted.

  The coating unit 520 includes first and second coating units 520a and 520b. The first coating unit 520a applies carbon black to one surface of the strip-shaped separator material TS supplied from the supply roll 510 using a carbon-bon black dispersion as a paint. The second coating part 520b applies carbon black to the other surface of the separator material TS. Thereby, the coating part 520 performs the coating process T1 (FIG. 3) which coats carbon black on the surface of the both sides of the separator material TS. As a result, carbon layers C1 are formed on the surfaces on both sides of the separator material TS. As the solvent for the dispersion, water, ethanol, toluene, cyclohexanone, or the like is used. As the first and second coating units 520a and 520b, various general coating apparatuses such as a bar coater, a roll coater, a gravure coater, and a die coater can be employed. In the example of FIG. 4, a die coater is employed.

  The particle size of the carbon black powder is preferably 20 to 200 nm. Carbon black powder tends to form aggregates in the paint, but in order to obtain high conductivity and conductive durability by heat treatment described later, it is necessary to use a paint that is devised not to form aggregates. preferable. For example, it is preferable to use a paint prepared by using carbon black powder in which dispersibility is enhanced by chemically bonding a functional group such as a carboxyl group to the surface of carbon black to enhance the repulsion between each other.

If the coating amount of the carbon black powder is, for example, 1 μg / cm ² or more, high conductivity and conductive durability can be obtained. For example, if it is set to ² μg / cm ² , more stable conductive durability can be obtained. The upper limit of the coating amount of the carbon black powder is preferably about 50 μg / cm ² , for example. Increasing the coating amount of the carbon black powder is not preferable because the effect of improving conductivity and conductivity durability is saturated while the cost is increased.

The heat treatment part 530 executes a heat treatment step T2 (FIG. 3) for heat-treating the separator material TS after the coating step. The heat treatment unit 530 is provided with an in-apparatus temperature adjustment apparatus and an in-apparatus oxygen partial pressure adjustment apparatus. Heat treatment step, it is preferable that the oxygen partial pressure in a range of ^1.3X10 -3 ^~21Pa, it is more preferably carried out in the range of 1.3 × ¹⁰ -2 ~21Pa. Moreover, it is preferable that the temperature of heat processing shall be the temperature range of 300-900 degreeC, for example. Among these, a temperature range of 600 to 800 ° C is particularly preferable, and a temperature range of 600 to 700 ° C is more preferable.

  In the heat treatment step, a part or all of titanium atoms (corresponding to “containing metal”) diffused outward from the separator material TS are oxidized to titanium oxide (corresponding to “oxide”). Thereby, on both surfaces of the separator material TS, a mixed layer TC containing the generated titanium oxide and carbon black particles in a portion near the surface of the separator material TS in the carbon layer C1 is formed. . The carbon layer C1 remains on the mixed layer TC to form an excess carbon layer C1s. That is, the mixed layer TC and the surplus carbon layer C1s are formed on the surfaces on both sides of the separator material TS by the heat treatment process. The thickness of the mixed layer TC is preferably in the range of 10 nm to 500 nm. Note that the heat treatment time can be appropriately set according to the heat treatment temperature and the target thickness of the mixed layer TC. Further, the thickness of the carbon layer C1 before the heat treatment is set to a thickness larger than the target thickness of the mixed layer TC. For example, when the separator material TS on which the carbon layer C1 with a thickness of 200 nm is formed is heated at 650 ° C. for 30 seconds, a mixed layer TC with a thickness of 100 nm is formed, and the remaining carbon layer C1 with a thickness of 100 nm is an excess carbon. It becomes layer C1s.

  The titanium oxide contained in the mixed layer TC includes a crystalline rutile structure, and this portion is excellent in conductive corrosion resistance. On the other hand, the carbon black contained in the mixed layer TC exists as carbon black particles of a single carbon black having a covalent bond between two carbon atoms, and is distributed along the thickness direction of the mixed layer TC. That is, the carbon black distributed in the mixed layer TC plays a role as a conductive path through which a current flows. Moreover, since carbon black is stable against oxidation, the conductivity of the carbon black contained in the mixed layer TC is stably maintained. Therefore, when a separator is produced using the separator material TS on which the mixed layer TC is formed, both high conductivity and conductive durability of the separator can be achieved.

  The heat-treated separator material TCCCS in which the mixed layer TC and the surplus carbon layer C1s are formed on the surfaces on both sides of the separator material TS is wound up in a roll shape by a winding roll 540.

  FIG. 5 is an explanatory diagram showing an example of the surplus carbon removing device 600 that executes the first and second removing steps T3 and T4 (FIG. 3) as the surplus carbon removing step. FIG. 5A shows a case where the first removal step T3 is executed, and FIG. 5B shows a case where the second removal step T4 is executed. The surplus carbon removing device 600 includes a supply roll 610, a surplus carbon removing unit 620, and a take-up roll 630.

  When the first removal step T3 is executed, as shown in FIG. 5A, a roll-shaped heat-treated separator material TCCCS is set on the supply roll 610 of the surplus carbon removing apparatus 600. The supply roll 610 sends the heat-treated separator material TCCCS toward the surplus carbon removing unit 620 with the first surface S1 of the heat-treated separator material TCCCS facing upward and the second surface S2 facing downward.

  The surplus carbon removing unit 620 includes a support base 622 and a water jet (hereinafter referred to as “WJ”) nozzle 621 disposed to face the support base 622. The surplus carbon removing unit 620 supports the downward second surface S2 of the heat-treated separator material TCCCS supplied from the supply roll 610 by the support base 622, and is included in the upward first surface S1 of the heat-treated separator material TCCCS. WJ is sprayed to the portion supported by the support base 622. In the portion where the WJ is applied, at least a part of the surplus carbon layer C1s is removed by the water pressure of the WJ. Accordingly, the surplus carbon removing unit 620 executes a first removing step T3 that removes the surplus carbon layer C1s on the first surface S1 of the heat-treated separator material TCCCCS supplied from the supply roll 610. In the present specification, “removing the surplus carbon layer” means removing all or a part of the surplus carbon layer. However, it is preferable to remove excess carbon in the power generation region (MEA region) of the fuel cell, the region where the seal member 80 is provided, and the region in contact with the support frame 31. As a condition of WJ injected from the WJ nozzle 621, for example, in the case of a flow rate of 10 L / min, it is preferable to set the water pressure within a range of 80 MPa to 100 MPa. This is because if the water pressure is less than 80 MPa, the excess carbon layer may not be completely removed, and if the water pressure exceeds 100 MPa, the separator material may be deformed. In addition, the range of this condition is not limited to this, and according to the flow rate, it is appropriately set within a range in which a surplus carbon layer can be removed by a desired amount without deforming the separator material. Is preferred.

  The single-sided carbon-removed separator material TCCS from which the surplus carbon layer C1s of the first surface S1 has been removed has the first surface S1 from which the surplus carbon layer C1s has been removed facing inward and the surplus carbon layer C1s has not been removed. It winds up in roll shape with the winding roll 630 so that 2 surface S2 may face an outer side.

  When performing the second removal step T4, as shown in FIG. 5B, the supply roll 610 of the surplus carbon removal device 600 has a single-sided carbon-removed separator material TCCS wound up in a roll shape. Set. The supply roll 610 has a single-sided carbon-removed separator material, with the surplus carbon layer C1s of the single-sided carbon-removed separator material TCCS facing upward, the second surface S2 from which the surplus carbon layer has been removed facing upward. The TCCS is sent to the surplus carbon removing unit 620.

  The surplus carbon removing unit 620 supports the first downward surface S1 of the single-sided carbon-removed separator material TCCS supplied from the supply roll 610 by the support base 622, and the second upwardly-separated carbon material of the separator material TCCS is directed upward. A second removal step T4 is performed in which WJ is sprayed onto the surface S2 to remove the surplus carbon layer C1s on the second surface. The water pressure conditions for WJ are the same as those described above.

  The carbon-separated separator material TCS from which the surplus carbon layer C1s on the first surface S1 has been removed and the surplus carbon layer C1s on the second surface S2 has been removed has the second surface S2 facing inward, Is wound up in a roll shape by a take-up roll 630 so that the surface S1 faces outward.

  Here, the reason why the excess carbon layer C1s on both sides of the separator material is removed is as follows. That is, when constituting the single cell 140, the surface of the separator is required to have high adhesiveness with the sealing member 80 (FIG. 2) and the support frame 31 of the MEA plate 30, but the excessive carbon layer C1s is left excessively. This is because this requirement cannot be satisfied.

  In the second removal step T4, the surface directly supported by the support base 622 of the surplus carbon removing unit 620 is the first surface S1 of the single-sided carbon-removed separator material TCCS. In the present embodiment, surplus carbon The mixed layer TC is exposed by removing the layer C1s. When the surface of the mixed layer TC passes through the support table 622, scratches are generated due to friction with the support table 622. The mixed layer TC exposed by removing the surplus carbon layer C1s on the second surface S2 is free from scratches.

  In the above description, the first removal process T3 is performed in the first operation of the surplus carbon removal apparatus 600 having one surplus carbon removal unit 620, and the second removal process T4 is performed in the second operation. Although the case has been described as an example, the first removal process T3 and the second removal process T4 may be performed collectively by one operation of the surplus carbon removing apparatus having the two surplus carbon removing units 620. Good.

  FIG. 6 is an explanatory diagram showing an example of a press working apparatus 700 that executes the press working process T5 (FIG. 3). The press working apparatus 700 includes a supply roll 710 and a press working machine 720. A roll-like carbon-removed separator material TCS is set on the supply roll 710. The supply roll 710 sends out the carbon-removed separator material TCS toward the press machine 720 with the first surface S1 of the carbon-removed separator material TCS facing upward and the second surface S2 facing downward.

  The press working machine 720 forms the openings 62, 64, 72, 74, 82, 84 for the respective manifolds at the opening positions 62a, 64a, 72a, 74a, 82a, 84a for the respective manifolds of the carbon-removed separator material TCS. At the same time, the cooling medium passage groove 54 is formed in the cooling medium passage groove position 54a on the first surface S1 side, and one anode side separator 50 can be produced by cutting at the cutting position CL. it can. In the manufactured anode side separator 50, the surface on which the cooling medium flow channel 54 is formed is the first surface S1 in which the scratch is generated in the second removal step T4, and the fuel gas flow channel ( The surface on which (not shown) is formed is a second surface S2 in which no scratch is generated.

  In the above embodiment, the method for manufacturing the anode-side separator 50 has been described, but the cathode-side separator 40 can be manufactured in the same manner. In this case, the surface on which the cooling medium flow channel is formed is the first surface S1, and the surface on which the oxidant gas flow channel is formed is the second surface S2.

  In the separator manufacturing method described above, the coolant passage is formed on the first surface S1 where the scratch is generated in the process of removing the surplus carbon layer, and the fuel gas is formed on the second surface S2 where the scratch is not generated. A fuel gas flow channel groove and an oxidant gas flow channel groove (reactive gas flow channel) constituting a flow channel and an oxidant gas flow channel (reactive gas flow channel) are formed. The reason for this will be described in the method for manufacturing a single cell described below.

C. Single cell manufacturing method:
FIG. 7 is an explanatory view showing a method for manufacturing the single cell 140. As shown in FIG. 7, the cathode side separator 40 is opposed to the MEA plate 30 so that the second surface S2 side where the oxidant gas flow channel groove is formed faces the MEA plate 30 side, and the anode side The side separators 50 are arranged to face each other so that the second surface S2 side where the fuel gas passage grooves are formed faces the MEA plate side. Then, the MEA plate 30 is sandwiched between the cathode side separator 40 and the anode side separator 50 and pressed to bond the support frame 31 of the MEA plate 30 and the separators 40 and 50 together. Thereby, the single cell 140 can be produced on the MEA plate 30.

  FIG. 8 is an enlarged cross-sectional view showing a part corresponding to the power generation section 32 of the MEA plate 30 in the single cell 140 (FIG. 7). 8 shows the anode side separator 50 of the single cell 140 adjacent to the cathode side separator 40 of one single cell 140 in the fuel cell stack 100 for convenience of explanation. The power generation unit 32 includes an MEA 321 disposed along the X-axis direction and a cathode-side gas diffusion layer 322 and an anode-side gas diffusion layer 323 sandwiching the MEA 321.

  As shown in the figure, in the anode side separator 50, a fuel gas passage groove 52 is formed, and the surface in contact with the anode side gas diffusion layer 323 of the power generation unit 32 is the second surface S2, and the cooling medium passage groove. The surface on which 54 is formed is the first surface S1. Similarly, in the cathode side separator 40, an oxidant gas flow path groove 42 is formed, and the surface in contact with the cathode side gas diffusion layer 322 of the power generation unit 32 is the second surface S2, and the cooling medium flow path groove 44. The surface on which is formed is the first surface. As described above, the first surface S1 is a surface in which uneven scratches are generated on the surface of the exposed mixed layer TC in the second removal step T4 (FIGS. 3 and 5) for removing the excess carbon layer C1s. In addition, the second surface S2 is a surface on which the scratch of the surface of the exposed mixed layer TC is not generated.

  Here, a case will be described in which a separator is manufactured by forming the oxidant gas flow channel groove 42 and the fuel gas flow channel groove 52 on the first surface S1. In this case, the surface having uneven scratches comes into contact with the MEA gas diffusion layers 322 and 323. There is a possibility that the unevenness is somewhat crushed by the press in the pressing process and the depth is shallow, but there is a possibility that it remains as a sharp uneven shape like a burr without being crushed. If sharp irregularities such as burrs remain on the surface, there is a possibility that the gas diffusion layers 322 and 323 may be stuck. Moreover, this may penetrate the gas diffusion layers 322 and 323 and pierce the MEA 321, possibly causing damage to the MEA 321. Furthermore, there is a possibility of causing a short circuit between the anode and the cathode of the MEA 321.

  On the other hand, the separators 40 and 50 manufactured according to the present embodiment have the first surface S1, which is a surface having scratches, on the side opposite to the surface in contact with the gas diffusion layers 322 and 323 of the power generation unit 32 and the cooling medium flow path. The surface on which the grooves 44 and 54 are formed is the surface that is adjacent to the gas diffusion layers 322 and 323 of the power generation unit 32. Thereby, it is possible to prevent the gas diffusion layers 322 and 323 and the MEA 321 from being damaged due to the uneven shape generated by the scratch, and finally short-circuiting between the anode and the cathode of the MEA 321.

  Further, the surface of the separators 40 and 50 where the cooling medium flow channel grooves 44 and 54 are formed is the first surface S1 having uneven scratches, but a sharp uneven shape such as a burr remains on the surface. Even if this is the case, the effect of this is small, as will be described below. That is, when stacking a plurality of single cells 140 to form a stack, the surface on which the cooling medium flow channel grooves 44 and 54 of the separators 40 and 50 of adjacent single cells 140 are formed, that is, a surface having a scratch. Certain first surfaces S1 come into contact with each other. In this case, if sharp irregularities such as burrs remain on the surface, there is a concern that the contact resistance may increase. However, in this case, since the fastening force applied in the stacking direction for stacking is applied to the concavo-convex portion and crushed, the influence on the contact resistance can be made very small.

D. Variations:
Each device used for executing each process of the above embodiment is an example, and the structure is not particularly limited as long as it has a function capable of executing the process of each process.

  The present invention is not limited to the above-described embodiments and modifications, and can be realized with various configurations without departing from the spirit thereof. For example, the technical features in the embodiments and modifications corresponding to the technical features in each embodiment described in the summary section of the invention are intended to solve part or all of the above-described problems, or In order to achieve part or all of the effects, replacement or combination can be performed as appropriate. Further, if the technical feature is not described as essential in the present specification, it can be deleted as appropriate.

DESCRIPTION OF SYMBOLS 30 ... MEA plate 31 ... Support frame 32 ... Power generation part 40 ... Cathode side separator 42 ... Oxidant gas channel groove 44 ... Coolant medium channel groove 50 ... Anode side separator 52 ... Fuel gas channel groove 54 ... Coolant medium channel Groove 62 ... Fuel gas inlet manifold opening 62a, 64a, 72a, 74a, 82a, 84a ... Manifold opening position 64 ... Fuel gas outlet manifold opening 72 ... Oxidant gas inlet manifold opening 74 ... Oxidant gas outlet manifold opening 80 ... Seal member 82 ... Cooling medium inlet manifold opening 84 ... Cooling medium outlet manifold opening 100 ... Fuel cell stack 140 ... Single cell 200 ... Cooling medium flow path surface 321 ... MEA (membrane electrode assembly)
322 ... Cathode side gas diffusion layer 323 ... Anode side gas diffusion layer 500 ... Surface treatment device 510 ... Supply roll 520 ... Coating section 520a ... First coating section 520b ... Second coating section 530 ... Heat treatment section 540 ... Winding roll 600 ... Surplus carbon removing device 610 ... Supply roll 620 ... Surplus carbon removing portion 621 ... WJ nozzle 622 ... Support base 630 ... Winding roll 700 ... Press working device 710 ... Supply roll 720 ... Press working machine C1 ... Carbon layer C1s ... excess carbon layer CL ... cutting position S1 ... first surface S2 ... second surface T1 ... coating step T2 ... heat treatment step T3 ... first removal step T4 ... second removal step T5 ... press working step TCCCS ... Separated separator material TCCS ... Single-sided carbon separator material TCS ... Carbon removed Separator material TS ... separator material TC ... the mixed layer

Claims (1)

A separator manufacturing method for forming a fuel cell by sandwiching a power generator,
(A) a coating step of coating carbon black on both surfaces of a metallic separator material mainly composed of titanium;
(B) After the coating step, by heat-treating the separator material, a mixed layer containing the carbon black and an oxide of a metal contained in the separator material on the surfaces on both sides of the separator material; A surplus carbon layer composed of the carbon black remaining on the mixed layer; and a heat treatment step for forming the surplus carbon layer,
(C) after the heat treatment step, a first removal step of supporting the first surface of both surfaces of the separator material and removing the excess carbon layer formed on the second surface;
(D) Second removal for supporting the second surface from which the excess carbon layer has been removed and removing the excess carbon layer formed on the first surface after the first removal step. Process,
(E) after the second removing step, a pressing process step of pressing the separator material with the second surface as a surface forming a reaction gas flow path for supplying a reaction gas to the power generation body; ,
A method for manufacturing a separator.

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