WO2010041694A1 - 固体高分子型燃料電池のセパレータ用ステンレス鋼板およびそれを用いた固体高分子型燃料電池 - Google Patents
固体高分子型燃料電池のセパレータ用ステンレス鋼板およびそれを用いた固体高分子型燃料電池 Download PDFInfo
- Publication number
- WO2010041694A1 WO2010041694A1 PCT/JP2009/067512 JP2009067512W WO2010041694A1 WO 2010041694 A1 WO2010041694 A1 WO 2010041694A1 JP 2009067512 W JP2009067512 W JP 2009067512W WO 2010041694 A1 WO2010041694 A1 WO 2010041694A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- stainless steel
- conductive
- base material
- separator
- passive film
- Prior art date
Links
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M8/00—Fuel cells; Manufacture thereof
- H01M8/02—Details
- H01M8/0202—Collectors; Separators, e.g. bipolar separators; Interconnectors
- H01M8/0204—Non-porous and characterised by the material
- H01M8/0206—Metals or alloys
- H01M8/0208—Alloys
- H01M8/021—Alloys based on iron
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/44—Ferrous alloys, e.g. steel alloys containing chromium with nickel with molybdenum or tungsten
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M8/00—Fuel cells; Manufacture thereof
- H01M8/02—Details
- H01M8/0202—Collectors; Separators, e.g. bipolar separators; Interconnectors
- H01M8/0204—Non-porous and characterised by the material
- H01M8/0223—Composites
- H01M8/0226—Composites in the form of mixtures
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M8/00—Fuel cells; Manufacture thereof
- H01M8/02—Details
- H01M8/0202—Collectors; Separators, e.g. bipolar separators; Interconnectors
- H01M8/0204—Non-porous and characterised by the material
- H01M8/0223—Composites
- H01M8/0228—Composites in the form of layered or coated products
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M8/00—Fuel cells; Manufacture thereof
- H01M8/10—Fuel cells with solid electrolytes
- H01M2008/1095—Fuel cells with polymeric electrolytes
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M8/00—Fuel cells; Manufacture thereof
- H01M8/10—Fuel cells with solid electrolytes
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/30—Hydrogen technology
- Y02E60/50—Fuel cells
Definitions
- the present invention relates to a polymer electrolyte fuel cell and a stainless steel material for a separator which is a constituent element thereof.
- Fuel cells are the next generation power generation system that is expected to be introduced and spread from both energy saving and environmental measures because it uses the energy generated during the reaction of hydrogen and oxygen.
- There are a plurality of types of fuel cells and examples include a solid electrolyte type, a molten carbonate type, a phosphoric acid type, and a solid polymer type.
- the polymer electrolyte fuel cell has a high output density and can be miniaturized, operates at a lower temperature than other types of fuel cells, and is easy to start and stop. For this reason, the polymer electrolyte fuel cell is expected to be used for electric vehicles and small cogeneration for home use, and has attracted particular attention in recent years.
- FIG. 1 is a diagram showing the structure of a polymer electrolyte fuel cell (hereinafter also simply referred to as “fuel cell”).
- FIG. 1 (a) is an exploded view of a single cell constituting the fuel cell
- FIG. b) is a perspective view of the whole fuel cell made by combining a number of single cells.
- the fuel cell 1 is an assembly (stack) of single cells.
- the single cell has a gas diffusion electrode layer (also referred to as a fuel electrode film, hereinafter also referred to as “anode”) 3 that acts as a battery cathode on one surface of the solid polymer electrolyte membrane 2.
- gas diffusion electrode layers also called oxidant electrode films, hereinafter also referred to as “cathodes”
- separators are formed on both surfaces. 5a and 5b are stacked.
- a water-cooled fuel cell in which a water separator having a cooling water flow path is arranged between the above-described single cells or between several single cells.
- the present invention is also directed to such a water-cooled fuel cell.
- a fluorine-based proton conductive membrane having a hydrogen ion (proton) exchange group is used as the solid polymer electrolyte membrane (hereinafter simply referred to as “electrolyte membrane”) 2 .
- the anode 3 and the cathode 4 are provided with a particulate platinum catalyst and graphite powder, and may be further provided with a catalyst layer made of a fluororesin having a hydrogen ion (proton) exchange group as required. In this case, the fuel gas or oxidizing gas and the catalyst layer come into contact with each other to promote the reaction.
- the fuel gas (hydrogen or hydrogen-containing gas) A is flowed from the flow path 6a provided in the separator 5a, and hydrogen is supplied to the fuel electrode film 3. Further, an oxidizing gas B soot such as air is flowed from the flow path 6b provided in the separator 5b, and oxygen is supplied. The supply of these gases causes an electrochemical reaction to generate DC power.
- the main functions required for a separator of a polymer electrolyte fuel cell are as follows. (1) Function as a “flow path” for uniformly supplying fuel gas and oxidizing gas into the battery surface, (2) A function as a “flow path” for efficiently discharging water generated on the cathode side from the fuel cell together with a carrier gas such as air and oxygen after reaction, (3) The function of becoming an electrical path in contact with the electrode films (anode 3 and cathode 4), and further serving as an electrical “connector” between single cells, (4) Between adjacent cells, function as a “partition” between the anode chamber of one cell and the cathode chamber of the adjacent cell, and (5) In the water-cooled fuel cell, the cooling water flow path and the adjacent cell Function as a “partition wall”.
- the base material of a separator (hereinafter simply referred to as “separator”) used in a polymer electrolyte fuel cell that is required to perform such a function is roughly classified into a metal material and a carbon material. is there.
- a separator made of a metal material such as stainless steel, Ti, or carbon steel is manufactured by a method such as press working.
- a method for manufacturing a separator using a carbon-based material there are a plurality of methods for manufacturing a separator using a carbon-based material.
- a graphite substrate is impregnated and cured with a thermosetting resin such as phenol or furan, and the carbon powder is kneaded with phenol resin, furan resin or tar pitch, and then pressed into a plate shape or
- a method of injection molding and firing the obtained member to form glassy carbon is exemplified.
- metal separator made of a metal-based material
- contact resistance contact resistance with the gas diffusion electrode layer
- the carbon-based material has an advantage that a lightweight separator can be obtained.
- problems such as gas permeability and low mechanical strength.
- it has been proposed to perform gold plating on the surface of the metal separator in contact with the electrode.
- the use of a large amount of gold in a mobile fuel cell and a stationary fuel cell such as an automobile has a problem from the viewpoint of economy and resource limitation.
- a coated metal separator material for a polymer electrolyte fuel cell disclosed in Patent Document 2 comprises an austenitic stainless steel material whose surface is pickled, and a conductive coating film formed on the surface of 3 to 20 ⁇ m.
- the conductive agent in the coating film is a mixed powder of graphite powder and carbon black.
- the fuel cell separator paint disclosed in Patent Document 3 uses graphite as a conductive material and is applied to the surface of a metal or carbon separator substrate for a fuel cell to form a conductive coating film. And containing 10% by weight or more of a copolymer (VDF-HFP copolymer) of vinylidene fluoride (VDF) and propylene hexafluoride (HFP) as a binder for the coating, Using an organic solvent compatible with the binder, the blending ratio of the conductive material and the binder is 15:85 to 90:10 by weight, and the blending ratio of the organic solvent is 50 to 95% by weight. It is.
- VDF-HFP copolymer vinylidene fluoride
- HFP propylene hexafluoride
- the conductive separator disclosed in Patent Document 8 includes a resin having a water-repellent or basic group and a conductive particulate material on a metal substrate. A conductive resin layer is provided.
- a fuel cell separator disclosed in Patent Document 4 is a fuel cell separator that forms a gas flow path in cooperation with a flat plate electrode of a unit cell, and includes a low electrical resistance metal plate, It consists of an amorphous carbon film that covers the metal plate and forms the gas flow path forming surface, and the hydrogen content CH of the amorphous carbon film is 1 atomic% ⁇ CH ⁇ 20 atomic%.
- This document proposes a method of depositing a carbonaceous film using a thin film forming technique (P-CVD method, ion beam deposition method, etc.) instead of the conductive coating film.
- the stainless steel plate disclosed in Patent Document 5 has a surface on which a large number of fine pits are formed over the entire region, and a large number of fine protrusions are erected on the periphery of the pits.
- This stainless steel plate is formed by dipping a stainless steel plate in a ferric chloride aqueous solution and performing alternating electrolytic etching.
- the separator plate disclosed in Patent Document 7 has a surface coated with an oxidation-resistant film, and the surface is a roughened uneven surface.
- the film defect portion on the top surface of the convex portion is a conductive portion.
- Patent Document 6 The means disclosed in Patent Document 6 is a means for heat-treating a stainless steel material in which carbon-based particles are pressure-bonded to the surface thereof, and a diffusion electrode layer is generated between the carbon-based particles and the stainless steel material. Adhesion increases, and electrical conduction between the carbon-based particles and the stainless steel material is ensured.
- Japanese Patent Laid-Open No. 10-228914 Japanese Patent Laid-Open No. 11-345618 International Publication 2003/044888 Pamphlet JP 2000-67881 A International Publication 2002/23654 Pamphlet International Publication 1999/199927 Pamphlet International Publication 2000/01025 Pamphlet International Publication 2001/18895 Pamphlet Japanese Patent No. 3365385 Japanese Patent Laid-Open No. 11-12018
- the method (A) is a method in which the surface oxide film of the stainless steel material is removed by pickling, and a conductive paint containing carbon is applied to the surface.
- the material to which the conductive coating is applied after the pickling has a higher contact resistance than the material that is pickled (the conductive material is not applied).
- the contact resistance value obtained from the material coated with the conductive paint is one digit higher than that of gold plating. For this reason, it cannot become an alternative technique of gold plating.
- the adhesion of the formed conductive coating film to the base material is insufficient, and the MEA (Membrane-Electrode Assembly) associated with the coating film peeling at the time of assembling the fuel cell and the operation / pause of the battery. ) Swelling / shrinkage causes problems such as peeling of the coating film.
- the thin film formation technique has a high processing cost and requires a long time for the processing. For this reason, this method is not suitable for mass production.
- the method (D) since a passive film is formed on the entire surface of the fine protrusions, the contact resistance with the gas diffusion electrode layer (carbon electrode) cannot be reduced.
- the method (E) described above can reduce the contact resistance with the gas diffusion electrode layer because the carbon diffusion electrode layer penetrates the passive film.
- a local cell is formed at the interface between the carbon diffusion electrode layer and the base material. For this reason, there exists a problem that corrosion progresses and a contact resistance rises. Therefore, this method is not suitable for practical use.
- Stainless steel separators are extremely practical in terms of material costs and processing costs.
- the high corrosion resistance of a stainless steel separator is largely due to the presence of a passive film on the surface.
- the passive film increases the contact resistance, there is a problem that the resistance loss increases when the generated electricity is collected by the stainless steel separator.
- Patent Document 9 uses conductive boride-based precipitates and / or carbide-based precipitates so as to penetrate the passive film on the surface of the stainless steel separator on which the passive film is formed. It is exposed to the surface from the inside of the stainless steel material. For this reason, these deposits and a gas diffusion electrode layer contact, and the electroconductivity between a stainless steel separator and a gas diffusion electrode layer is ensured.
- this method has a great effect on reducing the contact resistance, in the operating environment of the polymer electrolyte fuel cell, the oxide formed on the surface of the precipitate gradually grows with the operation. For this reason, there is a problem that the contact resistance increases during long-term operation, and the output voltage of the battery gradually decreases, and improvement is required. If this increase in contact resistance can be suppressed by an economically superior method, the problem can be solved.
- An object of the present invention is to solve the above-mentioned problem of increased contact resistance without impairing the corrosion resistance of a stainless steel separator, and for a polymer electrolyte fuel cell separator having excellent battery characteristics with little performance deterioration during long-time operation.
- the object is to provide a stainless steel material and a polymer electrolyte fuel cell using the same with high productivity, that is, at low cost.
- gold plating is a technology that has a low initial contact resistance and a slight increase in contact resistance after operation of the fuel cell.
- the electrical resistivity of carbon is 1375 ⁇ 10 ⁇ 6 ⁇ cm on average (mechanical / metal material for young engineers Maruzen Co., Ltd., page 325), while the resistivity of gold is 2.35 ⁇ 10 ⁇ 6 ⁇ cm. It is clear that it is difficult to achieve contact resistance comparable to that of gold plating by simply coating carbon on a metal separator (stainless steel separator).
- the carbon coating method achieves a low contact resistance that is close to that of gold plating, and a means that does not cause problems such as peeling even in the battery operating environment.
- the inventors examined. As a result, the following knowledge was obtained. By combining these, it becomes possible to solve problems that could not be achieved by the prior art.
- non-oxidizing acid is an acid other than an acid having an oxidizing power such as nitric acid, and examples thereof include hydrochloric acid, sulfuric acid, and hydrofluoric acid.
- a separator obtained from a stainless steel material with a carbon coating on the surface can reduce the initial contact resistance and suppress an increase in contact resistance under the fuel cell operating environment.
- the inventors of the present invention manufactured a fuel cell separator from a stainless steel material including a material originating from a stainless steel base material and having an electrically conductive material deposited on the surface of the stainless steel base material.
- the present inventors have found that the initial contact resistance of this separator is reduced as in the case of gold plating, and an increase in contact resistance due to passive film growth in a fuel cell operating environment is suppressed.
- the above-described treatment is performed by immersing the stainless steel material in an acidic solution containing sulfate ions (hereinafter referred to as “sulfuric acid solution”), preferably dilute sulfuric acid, or by anodic electrolysis of the stainless steel material in the sulfuric acid solution.
- sulfuric acid solution an acidic solution containing sulfate ions
- a conductive material can be obtained.
- the conductive material thus obtained is a non-crystalline (amorphous) or polycrystalline material composed of microcrystals containing O, S, Fe, Cr, and C as constituent elements.
- the present invention has been completed based on the above findings and is as follows.
- the present invention is a stainless steel material for a separator of a polymer electrolyte fuel cell, and includes a stainless steel base material, a passive film provided on the surface of the stainless steel base material, and conductive deposition. And the conductive precipitate penetrates the passive film and includes a material originating from the stainless steel base material.
- the “stainless steel base material” means a portion of the stainless steel material for the separator that does not include a passive film.
- the “passive film” is a film made of an insulating oxide that is formed on the surface of the base material when the stainless steel base material reacts with oxygen in the atmosphere.
- the conductive precipitate penetrates the passive film, the surface of the stainless steel material is composed of the surface of the passive film and the surface of the conductive precipitate.
- the conductive precipitate may contain O, S, Fe, Cr, and C as constituent elements and may be a polycrystalline body.
- a conductive layer made of a non-metallic conductive material is provided on the surface of the oxide, and the conductive layer may be electrically connected to the stainless steel base material through a conductive precipitate.
- the “non-metallic conductive substance” is a conductive substance in which a substance mainly responsible for conductivity does not have a metal bond, and a typical material thereof is graphitic carbon. Even when corrosion occurs in the non-metallic conductive material with the operation of the fuel cell using a separator made of a material having a non-metallic conductive material on the surface, metal ions hardly flow out. For this reason, an increase in contact resistance between the separator and the gas diffusion electrode layer hardly occurs due to the corrosion product. Moreover, it is difficult for metal ions to diffuse into the solid polymer electrolyte membrane and deteriorate the electrolyte membrane.
- the nonmetallic conductive material may contain graphitic carbon.
- the interplanar spacing of the graphitic carbon provided on the surface of the oxide is d002 ⁇ 3.390 mm.
- the ratio of the peak intensity of the diffraction line on the atomic plane to the peak intensity of the diffraction line on the (004) atomic plane is less than 0.1.
- the conductive layer may be formed by sliding a member containing graphitic carbon with respect to the surface composed of the surface of the passive film and the surface of the conductive precipitate.
- the average surface roughness of the surface composed of the surface of the passive film and the surface of the conductive precipitate is preferably 0.10 ⁇ m or more as Ra.
- Graphite carbon in which a conductive precipitate and a conductive layer are subjected to electrolytic treatment in an acidic solution containing sulfate ions at the same time as a stainless steel substrate composed of a stainless steel base material and a passive film, and at the same time function as a counter electrode in this electrolytic treatment It may be formed by sliding a member including the target member on the target member.
- the average surface roughness of the stainless steel substrate is preferably 0.10 ⁇ m or more as Ra.
- This invention provides a polymer electrolyte fuel cell provided with the separator obtained from said stainless steel material as another one aspect
- the stainless steel material according to the present invention includes a stainless steel base material, and a passive film and a conductive precipitate both provided on the surface of the stainless steel base material. It penetrates the passive film and contains substances originating from the stainless steel matrix.
- the surface of the stainless steel material is composed of the surface of the insulating passive film and the surface of the conductive precipitates that are discretely present, and the conductive precipitates are electrically connected to the stainless steel base material. It is a part.
- the “stainless steel base material” means a portion made of stainless steel (metal) in the stainless steel material, and means that a passive film formed on the surface of the stainless steel material is not included.
- the composition of the stainless steel base material is not particularly limited as long as it is a stainless steel capable of forming a passive film on the surface, and may be austenitic or ferrite as long as it is within the component range shown in JIS G4305.
- a typical steel composition is illustrated below.
- C 0.2% or less
- Si 2% or less
- Mn 10% or less
- Al 0.001% or more and 6% or less
- P 0.06% or less
- S 0.03% or less
- N 0.4% or less
- Cr 15% to 30%
- Ni 6% to 50%
- B 0% to 3.5%
- Stainless steel is exemplified. From the viewpoint of strength, workability, and corrosion resistance, in place of part of Fe, in mass%, Cu: 2% or less, W: 5% or less, Mo: 7% or less, V: 0.5% or less, Ti : 0.5% or less, Nb: 0.5% or less may be contained.
- ferritic stainless steel in mass%, C: 0.2% or less, Si: 2% or less, Mn: 3% or less, Al: 0.001% or more and 6% or less, P: 0.06% or less, S : 0.03% or less, N: 0.25% or less, Cr: 15% to 36%, Ni: 7% or less, B: 0% to 3.5%, balance Fe and stainless steel containing impurities Is exemplified.
- Cu: 2% or less, W: 5% or less, Mo: 7% or less, V: 0.5% or less, Ti : 0.5% or less, Nb: 0.5% or less may be contained.
- each component is as follows.
- % in content of an element means the mass%.
- C is an element necessary for ensuring the strength of the steel, but if contained excessively, the workability deteriorates, so the upper limit is made 0.2%. Preferably, it is 0.15% or less.
- Si is a component added as a deoxidizer.
- excessive addition causes a decrease in ductility, and particularly in the two-phase system, it promotes precipitation of the ⁇ phase. Therefore, the Si content is 2% or less.
- Mn is added because it has a function of deoxidizing and fixing S in steel as a Mn-based sulfide.
- austenite phase stabilizing element since it is an austenite phase stabilizing element, the austenite system contributes to the stabilization of the phase. In the case of a two-phase system, it is adjusted for the purpose of adjusting the ratio of the ferrite phase.
- it is adjusted for the purpose of adjusting the ratio of the ferrite phase.
- it may be contained in an amount of 10% or less when it is contained as a substitute for Ni.
- P and S are elements mixed in as impurities, and are 0.06% or less and 0.03% or less, respectively, in order to reduce corrosion resistance and hot workability.
- Al is added at the molten steel stage as a deoxidizing element.
- the steel of the present invention contains B to form an M 2 B-type boride.
- B is an element having a strong binding force with oxygen in the molten steel, the oxygen concentration should be lowered by Al deoxidation. Therefore, it is preferable to make it contain in 0.001 to 6% of range.
- N is an impurity in the ferrite system. N degrades the room temperature toughness, so the upper limit is preferably 0.25%. The lower one is more preferable, and it is better to make it 0.1% or less.
- N is an element effective for adjusting the austenite phase balance and improving corrosion resistance as an austenite forming element. However, excessive content deteriorates workability, so the upper limit is preferably made 0.4%.
- Cr is an element necessary to ensure the corrosion resistance of stainless steel, and it is necessary to contain 15% or more in the austenite system and ferrite system and 20% in the two phase system.
- a ferrite system if the Cr content exceeds 36%, production on a mass production scale becomes difficult.
- the austenite system if it exceeds 30%, the austenite phase becomes unstable by adjusting other alloy components.
- a two-phase system if it exceeds 30%, the ferrite phase increases and it becomes difficult to maintain a two-phase structure.
- Ni is an austenite phase stabilizing element, and it becomes possible to improve the corrosion resistance in the austenite system. If it is less than 6%, the austenite phase becomes unstable, and if it exceeds 50%, production becomes difficult. Even in the ferrite system, there is an effect of improving the corrosion resistance and toughness. However, if the content exceeds 7%, the ferrite phase becomes unstable, so 7% is made the upper limit. On the other hand, even in a two-phase system, there is an effect of improving corrosion resistance and toughness, and 1% or more is contained. However, if the content exceeds 10%, an excessive increase in the austenite phase and a decrease in the ferrite phase are caused.
- B is an optional additive element and has the effect of improving hot workability. To obtain this effect, 0.0001% or more is contained.
- B is an M 2 B type boride, specifically, M 2 B such as (Cr, Fe) 2 B, (Cr, Fe, Ni) 2 B containing Cr and Fe as a main component and a small amount of Ni and Mo.
- the conductive precipitates deposited in the stainless steel matrix as a type boride and deposited during pickling with sulfuric acid or the like are also deposited on the boride surface exposed on the surface of the stainless steel matrix during pickling. In addition, it exerts an auxiliary action to reduce the contact resistance of the surface of the stainless steel base material. In order to exert this effect, it is contained in an amount of 0.1% or more, but it is difficult to contain B in excess of 3.5% in the production by a normal dissolution method.
- Cu, W, Mo, V, Ti, and Nb are arbitrarily added elements, and are elements that improve strength, corrosion resistance, and the like. 2%, 5%, 7%, 0.5%, 0.5%, 0 The upper limit is 5%. If the content exceeds this, the above-described improvement effect is saturated, and the workability may be deteriorated.
- Rare earth elements (La, Ce, Nd, Pr, Y, etc.) are optional added elements that improve corrosion resistance and the like, and the upper limit of the total of rare earth elements is 0.1%. If the content exceeds 0.1%, the improvement effect is saturated, and the castability of stainless steel may be deteriorated (specifically, nozzle clogging may occur during continuous casting).
- Contains a material originating from a stainless steel base material means that a part of the dissolved or dropped stainless steel base material is contained, thereby allowing Fe, Cr, Ni, C, Si, Mn, Cu, Mo, W This means a conductive precipitate containing one or more elements constituting the stainless steel base material.
- the composition of the conductive precipitate is usually not the same as the composition of stainless steel, and the chemical and physical properties of the conductive precipitate are also different from those of the stainless steel matrix.
- the “precipitate” in the “conductive precipitate” is deposited on the surface of the stainless steel base material by depositing on the surface of the stainless steel base material, and on the surface other than the surface of the stainless steel base material.
- conductive precipitates Fe and Cr, which are mainly metal bonds in stainless steel, elute from conductive carbide, carbon simple substance, and stainless steel formed by combining with carbon contained in steel, for example.
- metal ions such as Cu, Mo, W, Ni, etc., deposited as metals again can be mentioned.
- non-oxidizing acid solution an acidic solution containing non-oxidizing acid ions
- non-oxidizing acid solution is an acidic solution containing an ion of an acid other than an acid having oxidizing power (oxidizing acid) such as nitric acid, and the stainless steel material is removed from its passive film. This means that the steel base material can be exposed.
- non-oxidizing acids include hydrohalic acids such as hydrochloric acid and hydrofluoric acid, and sulfuric acid.
- the non-oxidizing acid solution contained in this non-oxidizing acid solution may be one type or plural types, and may contain components effective for removing the passive film in addition to the non-oxidizing acid. Good. Further, as described later, an oxidizing acid ion may be included.
- the passive film on the surface can be thinned by immersing the stainless steel material in the non-oxidizing acid solution.
- the initial contact resistance of the separator formed from the stainless steel material after immersion is low, the passive film regrows when stored in the atmosphere for a long time, as well as in the severe environment under the actual fuel cell operating environment. There is a problem that the contact resistance increases.
- “smut” is generated when a stainless steel material is brought into contact with a non-oxidizing acid solution. Specifically, a material constituting a metal or a passive stainless steel is dissolved and / or released by a non-oxidizing acid (hereinafter collectively referred to as “dissolution”), and stainless steel ( A substance having a composition different from that of (metal) or passive is formed, and this is deposited and / or deposited (hereinafter collectively referred to as “precipitation”) on the surface of the stainless steel base material.
- dissolution a material constituting a metal or a passive stainless steel
- precipitation A substance having a composition different from that of (metal) or passive
- this smut may change the surface of the stainless steel material and impair the beauty of the surface. For this reason, it is customary to carry out a treatment for removing smut or to select at least an acid type so that at least coloring does not occur.
- conductive smut having electrical conductivity
- the idea was that it could be used to reduce the contact resistance or to suppress the increase in contact resistance during fuel cell operation. Based on this idea, further studies were conducted, and the conductive smut was excellent in three points: (1) electrical conductivity to the stainless steel base material, (2) adhesion to the stainless steel base material, and (3) chemical resistance. I found out.
- the conductive smut has such excellent characteristics for the following reason. That is, when a stainless steel material is immersed in a non-oxidizing acid solution, the passive film formed on the surface of the stainless steel base material is dissolved by the non-oxidizing acid, and the exposed stainless steel base material is also affected by the acid. Partially dissolved. Since the material containing the dissolved material originating from stainless steel is deposited on the surface of the stainless steel base material, the smut is present on the surface of the stainless steel base material. Therefore, when the smut has conductivity, the top of the conductive smut deposited on the surface of the stainless steel base material is electrically connected to the stainless steel base material.
- Such a state where the stainless steel base material is exposed can exist stably only when immersed in a non-oxidizing acid solution. If it is taken out from the solution and left in the atmosphere, or is immersed in a non-acidic solution by washing or the like, a passive film is rapidly formed on the exposed portion of the stainless steel base material. Although this passive film has poor electrical conductivity as described above, it has excellent corrosion resistance. Due to the formation of the passive film, the conductive smut is present in the stainless steel material so as to contact the stainless steel base material while penetrating the passive film. Therefore, the obtained stainless steel material has the characteristic that the contact resistance is low based on the conductive smut while having corrosion resistance based on the passive film.
- the conductive smut since the smut has a component constituting the molten stainless steel, and is a substance deposited on the surface of the stainless steel base material in a non-oxidizing acid having corrosive properties, the conductive smut is made of stainless steel. The potential difference with respect to the base material is small. For this reason, it is difficult for the conductive smut to form a local battery with the stainless steel base material. Therefore, it is unlikely that the conductive smut is corroded or the stainless steel base material around the conductive smut is corroded and the conductive smut is dropped off.
- the passive film formed so as to cover the surface of the exposed stainless steel base material grows so as to partially cover the conductive smut on the surface of the stainless steel base material. For this reason, the conductive smut in contact with the stainless steel base material is surrounded by the passive film. Therefore, the conductive smut is prevented from dropping from the stainless steel base material by the passive film.
- the composition of the conductive smut according to the present invention is not particularly limited as long as it has electrical conductivity.
- Stainless steel base material composition, types of non-oxidizing acid contained in non-oxidizing acid solution, types of substances other than non-oxidizing acid ions in non-oxidizing acid solution, contact with stainless steel material in non-oxidizing acid solution The composition varies greatly depending on the conditions (concentration, temperature, time, electrolysis conditions, etc.).
- the size is required to be larger than the thickness of the passive film, but the thickness of the passive film also varies depending on the composition of the stainless steel base material. For this reason, the lower limit may be appropriately set according to the thickness of the passive film.
- the upper limit when it is excessively larger than the thickness of the passive film, there is a concern that it may fall off from the stainless steel base material during the secondary processing to the separator or during use as the separator. For this reason, the upper limit value may be determined in relation to the thickness of the passive film from the viewpoint of preventing the dropout.
- the crystal structure is not particularly limited as long as electrical conductivity can be realized.
- An example of the conductive smut according to the present invention having the above characteristics will be described in detail below together with an example of a manufacturing method.
- a typical example of the method for forming the conductive smut according to the present invention is a treatment in which a stainless steel material is contacted, specifically immersed in a sulfuric acid solution, that is, an acidic solution containing sulfate ions (hereinafter also referred to as “sulfuric acid treatment”). .)
- a stainless steel substrate composed of a stainless steel base material and a passive film formed on the surface thereof is immersed in dilute sulfuric acid, the passive film formed on the surface is removed and a conductive smut is generated.
- This conductive smut is deposited so as to be sparsely present on the surface of the stainless steel base material or by substantially changing the processing conditions so as to substantially cover the surface of the stainless steel base material. Is possible.
- a stainless steel material having the conductive smut may be subjected to anodic electrolysis. Since the conductive smut inferior in corrosion resistance is dissolved and removed by this anode electrolysis, it is realized that only the conductive smut excellent in corrosion resistance is deposited as a conductive precipitate on the surface of the stainless steel base material.
- sulfuric acid electrolytic treatment in a sulfuric acid solution (hereinafter also referred to as “sulfuric acid electrolytic treatment”) may be performed.
- This sulfuric acid electrolysis treatment may be performed by direct current or alternating current.
- the stainless steel substrate may be directly energized using an electrode, or the stainless steel substrate may be indirectly energized without directly contacting a terminal from a power source.
- the sulfuric acid electrolytic treatment is performed in this manner, the smut inferior in corrosion resistance is dissolved during electrolysis on the surface of the stainless steel base material, so that only the one having excellent corrosion resistance is formed on the surface of the stainless steel base material.
- a conductive smut excellent in corrosion resistance and adhesion is present on the surface of the stainless steel base material by washing with water, preferably brushing or ultrasonic cleaning. Is realized.
- the conductive smut thus formed by the sulfuric acid electrolysis treatment component analysis and surface analysis were performed using STEM-EDX and ESCA for the sample extracted by the blank replica method.
- the conductive smut was an amorphous precipitate of 1 ⁇ m or less, as shown in FIGS.
- Table 1 shows the results of quantitative analysis of the outermost surface based on the narrow scan spectrum of the conductive smut.
- the conductive smut includes O, S, Fe, Cr, and C as main constituent elements.
- the chemical composition of the stainless steel base material on which the conductive smut to be analyzed is deposited is as follows. C: 0.02 mass%, Si: 0.21 mass%, Mn: 1.8 mass%, P: 0.018 mass%, S: 0.002 mass%, N: 0.015 mass%, Cr: 17.5% by mass, Ni: 12.2% by mass, Mo: 2.20% by mass and the balance Fe and impurities.
- the conductive smut is derived from a stainless steel base material, and O and S are mainly derived from sulfuric acid. Further, as shown in FIG. 2 (3), the crystalline state of the conductive smut is microcrystalline according to the electron diffraction of the sample extracted by the blank replica method, and the conductive smut is a multicrystal composed of microcrystals. It is a crystal.
- the method for generating the conductive precipitate according to the present invention on the surface of the stainless steel base material is not limited to the above. Any method may be used as long as it removes the passive film with a non-oxidizing acid solution or the like and deposits a conductive precipitate containing a substance originating from (derived from) the exposed stainless steel base material.
- the technical idea on which the present invention is based is that a conductive substance including a substance originating from a stainless steel base material is deposited so as to be in electrical contact with the stainless steel base material.
- the deposited elements are not limited to O, S, Fe, Cr, and C.
- an element having a smaller ionization tendency than hydrogen specifically, a stainless steel substrate containing copper or the like may be brought into contact with an acid to precipitate copper on the surface of the stainless steel base material.
- elements having a greater ionization tendency than hydrogen such as Mo and W, may be deposited on the surface of the stainless steel base material.
- the non-oxidizing acid solution may contain an oxidizing acid such as nitric acid.
- oxidizing acid solution mainly containing ions of an oxidizing acid (for example, nitric acid)
- the surface of the stainless steel substrate is oxidized. It is oxidized by acidic acid ions, and a passive film is formed on the surface of the stainless steel base material during pickling.
- the contact resistance of the stainless steel material is difficult to decrease.
- the smut tends to hardly adhere to the surface of the stainless steel base material, and in this respect, it is difficult to reduce the contact resistance.
- the conductive smut may be contained as a component of the solution for precipitating on the surface of the stainless steel base material.
- Conductive layer Stainless steel material for the purpose of protecting the conductive precipitates according to the present invention deposited on the surface of the stainless steel base material, preferably deposited so as to cover, or further reducing the contact resistance.
- a conductive coating layer (hereinafter referred to as “conductive layer”) containing a nonmetallic conductive material may be formed thereon.
- Non-metallic conductive materials include carbon black, conductive paint, and compound-based conductive materials such as ITO (indium tin oxide) and WC. It can be achieved and is preferred. Therefore, a coating layer containing graphite carbon (hereinafter referred to as “graphite layer”) among the conductive layers will be described in detail below.
- graphite layer a coating layer containing graphite carbon (hereinafter referred to as “graphite layer”) among the conductive layers will be described in detail below.
- any of scaly graphite, scaly graphite, expanded graphite, natural graphite, artificial graphite and the like may be used.
- a graphite having a shape with a large aspect ratio (diameter / height) such as scaly graphite or scaly graphite.
- the graphitic carbon to be coated is required to have (1) high conductivity and (2) sufficient corrosion resistance even in an atmosphere where sulfuric acid, fluorine ions, and the like are present. Furthermore, a preferable manufacturing method (to be described later) (sliding a stainless steel material and a member containing graphitic carbon, scraping off the graphitic carbon by the relief effect of the uneven surface of the stainless steel material surface and the conductive precipitate, (3) Easy to cover by sliding from the viewpoint of the method of adhering to the surface of the passive film on the surface of the stainless steel base material so that the a-axis direction is preferentially parallel to the surface of the passive film. A soft material is preferred.
- the electrical resistance value of highly crystalline graphitic carbon has anisotropy (Characteristics of graphite and technical development, Hitachi Powdered Metallurgy Technical Report No. 3 (2004), Table 1).
- the volume resistivity in the a-axis direction is as low as 4 to 7 ⁇ 10 ⁇ 5 ⁇ cm, and the c-axis direction is as high as 1 to 5 ⁇ 10 ⁇ 1 ⁇ cm. Since the electrical conduction in the a-axis direction is caused by conjugation of ⁇ bonds in sp2 bonds, the higher the crystallinity, the lower the volume resistivity.
- the volume resistivity in the a-axis direction is particularly low, the volume resistivity of the entire graphitic carbon is lowered, and the contact resistance is reduced. Brought about.
- the average resistance of carbon is 1375 ⁇ 10 ⁇ 6 ⁇ cm (mechanical and metal material for young engineers, Maruzen Co., Ltd., page 325)
- the low volume in the a-axis direction of graphitic carbon It is preferable to actively utilize the resistivity (4 to 7 ⁇ 10 ⁇ 5 ⁇ cm).
- a member containing highly crystalline graphitic carbon is a surface of a passive film and a conductive precipitate which is a surface of a stainless steel material provided with a conductive precipitate (hereinafter, “surface to be treated”). ),
- the graphitic carbon is torn into a scaly powder and adheres to the surface to be treated, and the surface of the passive film, preferably the graphite layer on the surface to be treated.
- the provided stainless steel material is obtained.
- the graphitic carbon adhering to the surface to be treated is a scaly powder having a high aspect ratio, the a-axis direction is parallel to the surface to be treated so that the influence of shearing force due to sliding is minimized. As a result, the number of the aligned materials increases.
- the graphite layer is particularly easy to move charges in a direction parallel to the surface of the passive film. For this reason, if the gas diffusion electrode layer is in contact with a separator manufactured from a stainless steel material provided with this graphite layer, there is no conductive precipitate in direct contact with the stainless steel base material at the contact portion, Even when it is in contact with the graphitic carbon of the graphite layer, the charge moves quickly to the vicinity of the conductive precipitate through the graphite layer having a particularly low volume resistivity, and moves to the stainless steel base material ( Current collection phenomenon) is realized.
- the separator and the gas diffusion electrode layer are collected by the current collecting action on the conductive precipitate by the graphite layer Electrical contact with is achieved.
- the electrical contact area between the gas diffusion electrode layer and the separator is dramatically increased as compared with the case where the graphite layer is not provided.
- the gas diffusion electrode layer and the separator are changed from a point contact to a surface contact state.
- a separator obtained from a stainless steel material having such a graphite layer exhibits a resistance value equivalent to that of gold plating at the surface portion, and has battery characteristics equivalent to those of the gold plating separator.
- the electric resistance in the surface direction of the conductive layer is lower than the electric resistance of the gas diffusion electrode layer.
- the electrical resistance of the gas diffusion electrode layer is about 0.08 ⁇ cm in the in-plane direction as a volume resistivity (Japan Automobile Research Institute, 2004 “Survey Report on Fuel Cell Vehicles”, Chapter 4, Technical Trend-1 214 Page Table 4-1-15). Therefore, the graphite layer having a structure in which the C-plane spacing of graphitic carbon is d002 ⁇ 3.390 mm and the a-axis direction of graphitic carbon is oriented parallel to the surface has a volume resistivity in the direction parallel to the surface of the graphite layer. It can be sufficiently lower than the volume resistivity of the diffusion electrode layer. Therefore, it is estimated that this current collection phenomenon is effectively generated when a separator made of a stainless steel material having a graphite layer is used.
- the orientation of the graphitic carbon in the graphite layer according to the present invention is determined by comparing the peak intensities of diffraction lines on the atomic plane obtained by performing wide-angle X-ray diffraction measurement on the graphitic carbon crystals in the graphite layer. , (110) atomic plane diffraction line peak intensity to (004) atomic plane diffraction line peak intensity ratio I (110) / I (004). If the index I (110) / I (004) is less than 0.1, the graphitic carbon in the graphite layer is oriented so that the a-axis direction is substantially parallel to the surface of the passive film.
- the graphite layer has higher thermal conductivity than the oxide passive film, in particular, the graphite layer has high crystallinity of the graphite carbon, and the a-axis direction of the graphite carbon is substantially parallel to the surface of the stainless steel.
- a thermal conductivity of 100 W / mK or more is achieved in the direction parallel to the surface of the graphite layer.
- the current flowing through the conductive precipitate is considered to be relatively high due to the current collection phenomenon.
- Joule heat is generated in the conductive precipitate, but it is expected that this heat is quickly diffused into the graphite layer. Therefore, it is suppressed that the volume resistivity of the conductive precipitate is increased due to Joule heat or the volume resistivity is increased due to thermal denaturation of the conductive precipitate, and the conductivity as a separator is reduced. It is suppressed.
- the method for forming the graphite layer as described above is not particularly limited.
- a dispersion liquid in which graphitic carbon is dispersed in an appropriate dispersion medium may be applied to the surface of stainless steel, and the dispersion medium may be removed by a technique such as volatilization, or may be formed by a technique such as sputtering or plasma CVD. Also good.
- the conductive precipitates protrude from the passive film, and therefore, the conductive precipitates are considered to easily scrape off the graphitic carbon. For this reason, graphitic carbon tends to be deposited around the conductive precipitate. Therefore, it is expected that the electrical connection between the graphite layer and the conductive precipitate is likely to occur stably by the sliding adhesion treatment.
- the specific structure of the member containing graphitic carbon is appropriately determined according to the specific method of the sliding adhesion treatment.
- the sliding adhesion treatment uses a lump or rod-shaped member made of graphitic carbon, or a lump or rod-shaped member obtained by solidifying graphite carbon with a binder such as a resin, and a sliding surface of a stainless steel material. This is performed by directly pressing this against a relative motion such as a reciprocating motion.
- rolling is performed while applying back tension with a rolling mill with a roll material made of graphite, or the tool part of the milling machine is replaced with a graphite round bar and the graphite is rotated while applying a certain load. It is possible to crush.
- the surface may be rubbed with a brush to which graphite powder is attached, or may be rubbed with a cloth (felt or the like) to which graphite powder is attached.
- the graphite powder becomes a member containing graphitic carbon.
- the graphitic carbon contained in the member containing graphitic carbon is preferably one having a small C-plane spacing and close to an ideal state.
- the member containing graphitic carbon is preferably composed of only graphitic carbon.
- Sliding conditions such as contact surface pressure, relative speed, and contact surface ratio are not particularly limited. What is necessary is just to set suitably so that a desired graphite layer can be formed, preventing the excessive wear of the member containing graphitic carbon.
- the desired graphite layer means a layered body in which graphitic carbon is deposited on a passive film on the surface of a stainless steel base material so that the a-axis direction is preferentially parallel to the film surface.
- the index I (110) / I (004) in the graphitic carbon in the graphite layer is preferably less than 0.1, and more preferably less than 0.05.
- Factors to be considered in setting the sliding conditions include the surface roughness of the stainless steel material, the precipitation state of the conductive precipitates on the surface of the stainless steel material, the hardness of the graphitic carbon, the thickness of the graphite layer, and the characteristics thereof.
- the surface roughness of the stainless steel material provided with the conductive precipitate is preferably 0.10 ⁇ m or more as the average surface roughness Ra.
- the upper limit of the surface roughness of the stainless steel material is not particularly limited from the viewpoint of adhesion. However, it is preferable that the average surface roughness Ra is 1/10 or less of the plate thickness from the viewpoint of reducing the possibility of cracking when processed into a separator shape by press molding or the like. In general, when surface roughness is imparted by pickling, the upper limit of the average surface roughness Ra is 2 to 3 ⁇ m. When applying the roughness by dull roll, a roughness of about several tens of ⁇ m can be sufficiently provided. However, since the effect is saturated and there is a problem of cracking during press molding, about 0.1 to 3 ⁇ m is practically sufficient.
- This surface roughness is a preferred embodiment in which when a separator obtained from a stainless steel material is incorporated in a fuel cell, only the steel material surface corresponding to the surface in contact with the gas diffusion electrode layer is required.
- the method for adjusting the stainless steel material to the above surface roughness is not particularly limited.
- (1) Surface treatment For example, a known etchant for etching a stainless steel material such as iron chloride is used, and etching is performed by setting the etchant concentration, the etchant temperature, the etching time, etc. according to the etching amount.
- Polishing by belt grinding Surface polishing is performed using a belt grinder in which polishing abrasive grains such as diamond, silicon carbide, and alumina are embedded on the surface to adjust to a predetermined surface roughness.
- FIG. 3 schematically shows the production process of a stainless steel material having a graphite layer employing the sliding adhesion treatment described above.
- the SEM image in the upper part of FIG. 3 is a result of observing the surface of a stainless steel material obtained by subjecting a stainless steel base material to roughening and subsequent conductive smut deposition treatment.
- the SEM image in the middle of FIG. 3 is a result of observing the surface of a stainless steel material having a graphite layer obtained by subjecting a stainless steel material having a conductive smut to the surface thereof to sliding adhesion.
- the conceptual diagram in the lower part of FIG. 3 is a partial cross-sectional view of a surface portion of a stainless steel material having a graphite layer.
- One common method of forming the graphite layer other than the sliding adhesion treatment is a method of producing a conductive paint containing graphitic carbon and applying this paint to the surface to be treated.
- this paint is specifically a mixture of graphitic carbon powder and a resinous binder, and the resin that serves as the binder does not have electrical conductivity, so compared with the case of coating with graphite carbon alone, There exists a tendency for the resistivity of the obtained graphite layer to become high.
- a layer made of a resinous binder (hereinafter referred to as “resin layer”) is formed by applying a resinous binder alone to the surface of the stainless steel material on which the conductive precipitate is present, that is, the surface to be treated. To do. Thereafter, a graphite layer is formed by the above-described sliding adhesion treatment.
- the resin layer is partially peeled by the shear stress resulting from the sliding. It is considered that the peeled resin layer is deposited on the surface to be treated including the resin layer while being mixed with a material (graphite carbon or the like) dropped from the member containing the graphitic carbon to form a graphite layer.
- the obtained graphite layer is considered to have a gradient composition structure in which the closer to the interface with the surface to be treated, the higher the content of the resinous binder, and the closer to the outermost surface, the higher the content of graphitic carbon. It is done.
- a coating composition containing graphitic carbon and 2% by mass or less of the resinous binder is applied to the surface to be treated. Is preferred.
- the content of the resinous binder in the coating composition exceeds 2% by mass of the content of graphitic carbon, the resistance of the conductive layer increases, the resistance heat loss for the fuel cell increases, The possibility that the output will be small increases.
- the resinous binder to be used is not limited as long as it is excellent in water resistance, oxidation resistance and chemical resistance.
- Fluororesin binders such as PTFE (polytetrafluoroethylene) and PVDF (polyvinylidene fluoride) used for forming a catalyst layer of a fuel cell are preferable, and among these, PTFE is particularly preferable.
- Electrolytic sliding adhesion treatment is a method in which electrolytic treatment and sliding adhesion treatment are performed simultaneously. Its specific configuration, electrolytic conditions (electrolyte composition, voltage application conditions, liquid temperature, etc.), sliding adhesion conditions (contact surface pressure, relative speed, contact area ratio, etc.), specific of carbon-containing member A shape, a composition, etc. are set suitably.
- electrolytic conditions electrolytic conditions
- electrolytic conditions electrolytic conditions
- voltage application conditions liquid temperature, etc.
- sliding adhesion conditions contact surface pressure, relative speed, contact area ratio, etc.
- specific of carbon-containing member A shape, a composition, etc. are set suitably.
- a specific example of the electrolytic sliding adhesion process will be described with reference to FIG.
- a member containing two graphitic carbons in this example, a graphite block
- a stainless steel substrate in this example, a plate material
- the power source is a DC power source in this example, but may be an AC power source. While applying a predetermined voltage from the power source, one graphite block is pressed against the other graphite block, and the plate is reciprocated so that the plate in between slides against the graphite block.
- the passive film on the surface of the plate material is removed, the stainless steel base material is exposed, conductive smut is deposited on the surface of the base material, and a graphite layer is formed by sliding between the graphite block and the plate material.
- the initial value of the contact resistance of the separator obtained from the stainless steel material provided with the graphite layer thus obtained to the gas diffusion electrode layer is particularly low. The reason is not clear.
- the conductive smut is difficult to grow because it is formed, the carbon from the graphite block can also be a component of the smut, and the graphite layer is directly formed on the surface of the stainless steel base material in the acidic solution. It may be affected.
- the surface roughness of the stainless steel base material to be processed in the electrolytic sliding adhesion treatment is 0.10 ⁇ m or more as the average surface roughness Ra, similarly to the surface roughness of the stainless steel material to be treated in the sliding adhesion treatment. It is preferable that
- the obtained resistance value is a value obtained by adding up the contact resistances of the both sandwiched surfaces
- the contact resistance value per one side of the gas diffusion electrode layer was obtained by dividing this by 2, and evaluated by this value.
- the current value and the voltage drop were measured using a digital multimeter (KEITLEY 2001 manufactured by Toyo Corporation).
- Interplanar measurement of coated graphite Interplanar spacing of the graphite to be coated is measured by 2 ⁇ / ⁇ scanning method, and Gakushin method 117 (Lattice constant of carbon material) is measured using an X-ray diffraction measurement device (RINT 2000, manufactured by Rigaku Corporation). And 20% by mass of standard Si in accordance with the crystallite size measurement method (revision plan 04/07/08), and the baseline correction, the profile correction, etc. are performed, and the accurate 002 plane spacing (d002), that is, The C-plane spacing was calculated.
- Carbon-X Ver1.4.2 carbon material X-ray diffraction data analysis program manufactured by Realize Science and Technology Center Co., Ltd. was used.
- the graphite block itself was measured by X-ray diffraction.
- the graphite powder used was measured by X-ray diffraction.
- the graphitic carbon was coated by vacuum deposition, it was difficult to measure the face spacing as it was. For this reason, vapor deposition was performed thickly until the d002 peak appeared clearly, a sample exclusively for XRD measurement was made, and X-ray diffraction measurement was performed on this sample.
- the details of the stainless steel separator plate used in the cell are as follows.
- the separator sheet material before surface treatment is pressed on both sides (anode side and cathode side) in the shape shown in FIG. 1 to form a gas flow path having a groove width of 2 mm and a groove depth of 1 mm. It was.
- the polymer electrolyte single cell battery was assembled using this separator.
- evaluation was performed using a single cell. This is because in the state where multiple cells are stacked, the quality of the stacking technique is reflected in the evaluation result.
- Initial battery voltage Characteristic evaluation is the highest in 48 hours after the start of measurement by measuring the voltage of a single cell battery from the time when an output of 0.5 A / cm 2 is obtained after flowing fuel gas into the battery.
- the battery voltage was defined as the initial battery voltage.
- Example 1 The procedure for preparing evaluation samples of test numbers 1 to 9 for confirming the conventional invention is shown below.
- Test number 1 (commercially available SUS)
- the SUS316L stainless steel plate (thickness: 4 mm) shown in Table 2 was used.
- a predetermined separator shape was finished by cutting and electric discharge machining to obtain a test separator.
- Test number 2 (gold plating) A SUS316L stainless steel plate (thickness: 4 mm) shown in Table 2 was made into a separator shape by cutting and electric discharge machining. The stainless steel plate having the separator shape thus obtained is degreased, washed, surface activated, and washed in this order, and further using a commercially available cyanogen gold potassium solution, the electrode contact surface of the unit cell (with the gas diffusion electrode layer) The surface corresponding to the contact portion) was plated with gold to obtain a test separator. The thickness of the gold plating was 0.05 ⁇ m.
- Test Nos. 3 to 5 Comparison Prior Art 1 (Following Patent Document 10)
- the method disclosed in Patent Document 10 was carried out using 316L, 304, and 430 (all of which had a thickness of 0.15 mm) among the four types of stainless steel plates shown in Table 2.
- the surface of the stainless steel plate was rubbed with a felt coated with carbon black having an average particle size of about 0.05 ⁇ m. Thereafter, the surface of the stainless steel plate was carbon coated by rolling at a rolling reduction of 3%.
- the separator used for battery evaluation was obtained by processing into a predetermined shape by press molding.
- Test No. 6 Comparison Prior Art 2 (Further Examination of Patent Document 2)
- a confirmation test was performed using a 430 stainless steel plate (thickness: 0.15 mmt) among the stainless steel plates shown in Table 2.
- a stainless steel plate was pressed into a predetermined separator shape. Thereafter, the stainless steel plate having a separator shape was pickled for 10 seconds using a 60 ° C. solution containing 10% by mass of hydrochloric acid.
- a paint was prepared by mixing 35 parts by weight of a water-dispersible paint of polyolefin resin to which water-dispersible carbon black was added with respect to 100 parts by weight of graphite powder (MCMB average particle size 6 ⁇ m manufactured by Osaka Gas Co., Ltd.). This paint was applied to the front and back surfaces of the stainless steel plate after pickling at a thickness of 30 ⁇ m and subjected to a baking treatment at 120 ° C. for 1 minute to obtain a test separator.
- MCMB average particle size 6 ⁇ m manufactured by Osaka
- Test No. 7 Comparison Prior Art 3 (Further Examination of Patent Document 3)
- 304 stainless steel plate (0.15 mmt) was pressed into a predetermined separator shape.
- a styrene-butadiene copolymer emulsion of a random copolymer of styrene-butadiene (solid content 40% by weight)
- a powder was prepared by mixing carbon black at a ratio of 20 parts by mass with respect to 80 parts by mass of graphite powder (MCMB average particle size 6 ⁇ m, manufactured by Osaka Gas Co., Ltd.).
- the above styrene-butadiene copolymer emulsion was mixed at a ratio of 40 parts by mass with 60 parts by mass of the powder composed of carbon and graphite, and the mixture was kneaded to obtain a paint.
- the obtained paint was applied to a stainless steel plate having a separator shape with a doctor blade.
- the stainless steel plate having the paint layer was dried at 150 ° C. for 15 minutes to obtain a test separator.
- Test No. 8 Comparison Prior Art 4 (Further Examination of Patent Document 4)
- a 316L stainless steel plate (thickness: 0.15 mm) was formed into a separator shape by pressing.
- Amorphous carbon was deposited on a stainless steel plate having a separator shape by an ion beam deposition method using graphite as a target material to obtain a test separator.
- Test number 9 (Comparison prior art (Follow-up of Patent Document 5)) A ferric chloride aqueous solution containing 20 g / l of Fe 3+ and having a liquid temperature of 50 ° C. was prepared.
- the 316L stainless steel sheet was subjected to alternating electrolytic treatment under the conditions of an anode current density of 5.0 kA / m 2 , a cathode current density of 0.2 kA / m 2 , an alternating electrolytic cycle of 2.5 kHz, and a treatment time of 60 seconds.
- the treated stainless steel plate was processed into a predetermined separator shape by pressing to obtain a test separator.
- evaluation samples according to test numbers 10 to 14 were prepared by the following procedure. First, four types of stainless steel plates shown in Table 2 were processed into the separator shapes 5a and 5b shown in FIG. 1 by cutting and electric discharge machining.
- the portion corresponding to the contact portion with the gas diffusion electrode layer on the stainless steel plate having the processed separator shape was polished with # 600 polishing paper.
- the surface roughness of the portion was about 0.25 ⁇ m as Ra.
- Table 5 shows the results of the above evaluation performed on the obtained test members.
- the carbon-dispersed paint used in Test No. 9 is obtained by sufficiently dispersing carbon black at a ratio of 10% by weight with respect to the acrylic aqueous resin diluted to 10% by weight.
- a carbon material obtained by heating and carbonizing mesophase microspheres produced by heat treatment of petroleum pitch and bulk mesophase which is a matrix of the microspheres was prepared. By changing the heating temperature and time of the graphitization heat treatment for the obtained carbon material, graphitic carbon having various face spacings was obtained.
- Table 6 shows the heating temperature and time, and the interplanar spacing of the obtained graphitic carbon. Carbons 1 to 3 are outside the scope of the present invention, and carbons 4 to 9 are within the scope of the present invention.
- Example 5 The same treatment as in Test No. 14 (Invention 5) of Example 1 was performed to deposit a conductive smut to obtain a stainless steel plate having a separator shape.
- the separator made of 316L stainless steel sheet coated with graphitic carbon with a surface spacing exceeding 3.390 mm has a relatively large contact resistance (contact surface pressure: 20 kgf / cm 2 ) of more than 15 m ⁇ ⁇ cm 2 after the corrosion resistance test.
- the battery deterioration level was also lower than ⁇ 2.0 ⁇ V / hour (larger as a negative value). From these results, it was shown that better performance can be obtained as the interplanar spacing d002 of graphitic carbon is smaller.
- Example 3 The following experiment was conducted to confirm a desirable range in the surface roughness of the stainless steel plate.
- the raw materials having various surface roughnesses were obtained by adjusting the abrasive roughness of the belt grinder and the ferric chloride etching time.
- Table 8 shows changes in contact resistance and fuel cell characteristics when the surface roughness is changed.
- the battery deterioration level is slightly lowered (becomes larger as a negative value). This is presumed to be because the conductive precipitate and / or the graphite pressure-bonded to the upper portion thereof easily peel off.
- Example 4 When the sulfuric acid electrolytic treatment is performed on the stainless steel plate before the conductive precipitate is formed, the conductive smut is formed and the graphite layer is formed by sliding the stainless steel plate using graphite carbon as a counter electrode. The Example for verifying the effect at the time of performing simultaneously is shown.
- FIG. 5 conceptually shows means for simultaneously performing the sulfuric acid electrolysis treatment and the sliding adhesion treatment.
- a stainless steel plate roughened with a belt grinder was used as a member to be processed, and a voltage of 0.4 V was applied to form a conductive smut and a graphite layer.
- Table 9 shows the results of the above evaluation performed on the obtained stainless steel plate.
- the stainless steel materials of test numbers 31 and 32 obtained in this example were confirmed to have a low contact resistance and particularly a high initial battery voltage.
- Example 5 evaluation samples having different graphite layer forming methods were prepared as shown in Table 7, and the influence of the orientation of the coated graphitic carbon was investigated.
- the material used is a SUS316L stainless steel plate shown in Table 2.
- a graphite layer was formed as follows. A felt-like cloth having a graphitic carbon powder adhered thereto or a roll wound with the cloth was rubbed against a stainless steel plate (SUS316L) to adhere the graphite carbon powder. Subsequently, the stainless steel plate with the graphitic carbon adhered was rolled at a reduction rate of 2% using a normal roll pair.
- a graphite layer was formed as follows.
- a PTFE dispersion solution manufactured by Daikin Industries, Ltd., PTFE (Polyfluorocarbon-PTFE-Dispersion-D-1)
- PTFE Polyfluorocarbon-PTFE-Dispersion-D-1
- SUS316L stainless steel plate having conductive smut deposited on the surface and dried.
- I (110) / I (004) which is the ratio of the peak intensity of the (110) atomic plane diffraction line to the peak intensity of the (004) atomic plane diffraction line, is expressed as a graphitic carbon crystal in the graphite layer. This was used as an index to quantitatively represent the orientation of the.
- Table 10 shows the relationship between orientation, contact resistance, and battery characteristics.
- I (110) / I (004) when I (110) / I (004) is less than 0.1, the contact resistance is low, the initial battery voltage is as high as 0.7 V or more, and the battery deterioration is small. It has also been confirmed that particularly excellent characteristics can be obtained when I (110) / I (004) is less than 0.05.
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Electrochemistry (AREA)
- Sustainable Development (AREA)
- General Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Sustainable Energy (AREA)
- Life Sciences & Earth Sciences (AREA)
- Manufacturing & Machinery (AREA)
- Composite Materials (AREA)
- Mechanical Engineering (AREA)
- Organic Chemistry (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Fuel Cell (AREA)
- Chemical Treatment Of Metals (AREA)
- Other Surface Treatments For Metallic Materials (AREA)
Abstract
Description
(1)燃料ガス、酸化性ガスを電池面内に均一に供給する“流路”としての機能、
(2)カソード側で生成した水を、反応後の空気、酸素といったキャリアガスとともに燃料電池から効率的に系外に排出する“流路”としての機能、
(3)電極膜(アノード3、カソード4)と接触して電気の通り道となり、さらに単セル間の電気的“コネクタ”となる機能、
(4)隣り合うセル間で、一方のセルのアノード室と隣接するセルのカソード室との“隔壁”としての機能、および
(5)水冷型燃料電池では、冷却水流路と隣接するセルとの“隔壁”としての機能。
金属セパレータに関する上記の問題を解決する方法の一つとして、特許文献1に示されるように、金属セパレータの基材の電極と接する表面に、金めっきを施すことが提案されている。しかしながら、自動車等の移動体用燃料電池および定置用燃料電池に金を多量に使用することは、経済性および資源量制約の観点から問題があった。
以下に、これまでに金属セパレータ表面をカーボンで被覆する方法として提案されている技術を列挙する。
上記(D)の方法は、微細突起の全面に不動態皮膜が形成されるため、ガス拡散電極層(カーボン電極)との接触抵抗を低減することはできない。
従来の技術の確認検証を行ったところ、初期の接触抵抗が低く、かつ燃料電池運転後の接触抵抗の上昇が軽微な技術は、金めっきであった。
これまで提案されているカーボンコート方法を検証したところ、効果は認められるがその改善程度は不十分であって、(1)金めっきと比較して高い接触抵抗値であること、(2)被覆方法によっては電池運転環境で剥離が生じてその効果が持続しないこと、等の問題が認められた。
「非酸化性酸」とは、硝酸など酸化力を有する酸以外の酸であって、例えば塩酸、硫酸、ふっ酸が例示される。
本発明は、一態様として、固体高分子形燃料電池のセパレータ用ステンレス鋼材であって、ステンレス鋼母材と、いずれもこのステンレス鋼母材の表面上に設けられた不動態皮膜および導電性析出物とを備え、導電性析出物は、不動態皮膜を貫通しており、ステンレス鋼母材を起源とする物質を含む、ステンレス鋼材を提供する。
「不動態皮膜」とは、ステンレス鋼母材が大気中の酸素などと反応することにより母材表面に形成される絶縁性の酸化物からなる皮膜である。
上記の導電性析出物が、O、S、Fe、CrおよびCを構成元素として含み、多結晶体であってもよい。
ここで、「非金属導電性物質」とは、導電性を主として担う物質が金属結合を有していない導電性物質であり、その典型的な材料は黒鉛質炭素が挙げられる。非金属導電性物質を表面に備える材料からなるセパレータを用いてなる燃料電池の運転に伴い、非金属導電性物質において腐食が発生しても、金属イオンが流出することがほとんどない。このため、腐食生成物によってセパレータとガス拡散電極層との間の接触抵抗の上昇が起こりにくい。しかも、固体高分子電解質膜内に金属イオンが拡散して電解質膜を劣化させることも起こりにくい。
黒鉛質炭素を含む場合は、酸化物の表面に設けられた黒鉛質炭素の面間隔がd002≦3.390Åであることがさらに好ましい。
不動態皮膜の表面と導電性析出物の表面とからなる表面の平均表面粗さがRaとして0.10μm以上であることが好ましい。
本発明は、他の一態様として、上記のステンレス鋼材から得られたセパレータを備える固体高分子型燃料電池を提供する。
本発明に係るステンレス鋼材は、ステンレス鋼母材と、いずれもこのステンレス鋼母材の表面上に設けられた不動態皮膜および導電性析出物とを備え、導電性析出物は、不動態皮膜を貫通しており、ステンレス鋼母材を起源とする物質を含む。係る構成において、ステンレス鋼材の表面は、絶縁性の不動態皮膜の表面と離散的に存在する導電性析出物の表面とからなり、この導電性析出物はステンレス鋼母材への電気的な接続部位となっている。
オーステナイト系ステンレス鋼として、質量%で、C:0.2%以下、Si:2%以下、Mn:10%以下、Al:0.001%以上6%以下、P:0.06%以下、S:0.03%以下、N:0.4%以下、Cr:15%以上30%以下、Ni:6%以上50%以下、B:0%以上3.5%以下、残部Feおよび不純物を含有するステンレス鋼が例示される。強度、加工性、耐食性の観点から、更にFeの一部に代えて、質量%で、Cu:2%以下、W:5%以下、Mo:7%以下、V:0.5%以下、Ti:0.5%以下、Nb:0.5%以下が含有されていてもよい。
Cは、鋼の強度を確保するために必要な元素であるが、過剰に含有させると、加工性が劣化するので上限を0.2%とする。好ましくは、0.15%以下である。
Mnは、脱酸や鋼中のSをMn系の硫化物として固定する作用があるために、添加される。一方で、オーステナイト相安定化元素であるために、オーステナイト系では相の安定化に寄与する。また、2相系ではフェライト相の比率を調整する目的で調整される。しかし、過剰に含有させると耐食性が低下する弊害もあるが、Niの代替として含有させる場合には10%以下含有させてもよく、フェライト系ではNi代替としての必要性がないため上限を3%とする。
Alは、脱酸元素として溶鋼段階で添加する。本発明鋼ではBを含有させM2B型硼化物を形成させるが、Bは溶鋼中酸素との結合力が強い元素であるので、Al脱酸により酸素濃度を下げておくのがよい。そのため、0.001~6%の範囲で含有させるのがよい。
すなわち、非酸化性酸溶液にステンレス鋼材を浸漬させると、ステンレス鋼母材の表面上に形成されている不動態皮膜が非酸化性酸により溶解され、さらに露出したステンレス鋼母材もその酸によって一部溶解される。この溶解したステンレス鋼起源の物質を含む物質がステンレス鋼母材の表面上に析出したものがスマットであるから、そのスマットはステンレス鋼母材の表面上に存在していることになる。したがって、スマットが導電性を有している場合には、そのステンレス鋼母材の表面上に析出した導電性スマットの頂部は、ステンレス鋼母材と電気的に接続されている。
上記の特性を有する本発明に係る導電性スマットの一例を、製造方法の例とともに次に詳しく説明する。
使用装置 : アルバック・ファイ株式会社製 Quantera SXM
X線源 : mono-AlKα(hν=1486.6eV)
検出深さ : 数nm(光電子取出角45°)
X線ビーム径 : 直径100μm(ポイント分析)
帯電中和銃 : 1.0V,20μA
また、表1に示されるNおよびMoの「*」は、これらの元素のピークが他の元素のピークと重なるため定量分析ができなかったことを意味する。
ステンレス鋼母材の表面上に析出した、好ましくは被覆するように析出した上記の本発明に係る導電性析出物を保護したり、接触抵抗をさらに低減させたりする目的等で、ステンレス鋼材上に非金属導電性物質を含んでなる導電性の被覆層(以下、「導電層」という。)を形成してもよい。
結晶性の高い黒鉛質炭素の電気抵抗値には、異方性がある(黒鉛の特性と技術展開 日立粉末冶金テクニカルレポート No.3(2004) 表1 )。a軸方向の体積抵抗率は4~7×10-5Ωcmと低く、c軸方向は1~5×10-1Ωcmと高い。このa軸方向の電気伝導は、sp2結合におけるπ結合が共役することによってもたらされているので、結晶性が高いほど体積抵抗率も低くなる。このため、d002≦3.390Åの結晶性が高い黒鉛質炭素を用いることで、a軸方向の体積抵抗率が特に低くなり、黒鉛質炭素全体の体積抵抗率が低くなり、接触抵抗の低下がもたらされる。一般的なカーボンの抵抗が平均1375×10-6Ωcm(若い技術者のための機械・金属材料 丸善株式会社 325ページ)であることを考慮にいれると、黒鉛質炭素のa軸方向の低い体積抵抗率(4~7×10-5Ωcm)を積極的に活用することが好ましい。
黒鉛質炭素の腐食は結晶性が乱れた部分において発生しやすい。このため、結晶性が高いほど黒鉛質炭素は腐食しにくい。したがって、黒鉛層に含まれる黒鉛質炭素の結晶性が高いほど酸・アルカリのいずれの環境下においても優れた耐食性を有し、イオン溶出等でMEA膜を汚染し性能劣化を誘引する可能性が低い。特に、d002≦3.390Åの黒鉛質炭素を含む黒鉛層はステンレス鋼材に対する腐食防止層として効果的に機能をする。また、ステンレス鋼母材の表面上の不動態皮膜が成長することを抑制するという機能が長期にわたって維持されるため、接触抵抗の経時変化も生じにくい。
黒鉛質炭素の可塑性は、C面間隔が小さくなり理想的な結晶状態である3.354Åに近づくほど良好になる。したがって、C面間隔がd002≦3.390Åの黒鉛質炭素は可塑性が良好であるため、この黒鉛質炭素を含む部材を被処理表面と摺動させると、被処理表面に対する被覆が容易になる。
摺動付着処理では、黒鉛質炭素を含む部材を被処理表面に対して摺動させ、不動態皮膜表面の凹凸の凸部や導電性析出物のやすり効果により黒鉛質炭素を削り取り、黒鉛質炭素を、不動態皮膜の表面、好ましくは導電性析出物の表面にa軸方向が優先的に皮膜表面と平行となるように付着させる。
所望の黒鉛層とは、黒鉛質炭素がステンレス鋼母材の表面上にある不動態皮膜上にa軸方向が優先的に皮膜表面と平行となるように付着された層状体を意味する。また、黒鉛層における黒鉛質炭素における指標I(110)/I(004)が0.1未満であれば好ましく、0.05未満であればさらに好ましいことは前述のとおりである。
(1)表面処理;例えば塩化鉄などステンレス鋼材をエッチングするための公知のエッチャントを用い、エッチング量に応じてエッチャント濃度、エッチング液温度、エッチング時間などを設定してエッチングを行う。
これらの粗面化のための処理は、導電性析出物を析出させる前のステンレス鋼基材に対して行うことが好ましい。
摺動付着処理以外の黒鉛層の一般的な形成方法の一つが、黒鉛質炭素を含有する導電性塗料を作製し、この塗料を被処理表面に塗布する方法である。しかしながら、この塗料は具体的には黒鉛質炭素粉末と樹脂性結着剤との混合物であり、結着剤となる樹脂は導電性を持たないため、黒鉛質炭素単独で被覆する場合に比べ、得られた黒鉛層の抵抗率が高くなる傾向がある。
導電性析出物がその表面に存在するステンレス鋼材の表面、すなわち被処理表面に樹脂性結着剤を単独で塗布して樹脂性結着剤からなる層(以下「樹脂層」という。)を形成する。その後、上記の摺動付着処理によって黒鉛層を形成する。
電解摺動付着処理は、電解処理と摺動付着処理とを同時に行う方法である。その具体的な構成、電解条件(電解液組成、電圧印加条件、液温など)、摺動付着条件(接触面圧、相対速度、接触面積比率など)、黒鉛質炭素を含む部材の具体的な形状や組成などは適宜設定される。ここでは、電解摺動付着処理の具体的な一例を図5に基づいて説明する。
1.ステンレス鋼板の準備
(1)鋼板
市中で入手可能な汎用ステンレス鋼板4種を実施例に用いる素材として用いた。表2にこれらの鋼板の組成を示す。使用したステンレス鋼板の厚さは約4mmまたは0.15mmであった。
これらのステンレス鋼板の表面粗度の調整は次の手段(A)、(B)および(C)のいずれかにより行った。
原料;塩化第二鉄無水物(和光純薬工業株式会社製)、純水
表面処理液;45ボーメ度の塩化第二鉄水溶液
表面処理条件;60℃の処理液に、ステンレス鋼板を40秒浸漬
処理後の水洗・乾燥条件;表面処理後の素材は十分に流水洗浄し、その後70℃のオーブンで十分に乾燥させた。
表面に研磨砥粒が埋め込まれたベルトグラインダーを用いて、所定の表面粗度になるまでステンレス鋼板の表面研磨を行った。
圧延ロールの研削仕上げの程度が異なるため表面粗さが異なる圧延ロールを用意した。これらの圧延ロールを用いてステンレス鋼板を圧延することにより、ステンレス鋼板の表面粗度を調整した。
論文等(例えば チタン Vol.54 No.4 P259)で報告されている方法に準じ、図4に模式的に示す装置を用いて、接触抵抗の測定を実施した。面積が1cm2であってガス拡散電極層に使用されるカーボンペーパー(東レ(株)製 TGP-H-90)でセパレータ用シート材を狭持し、これを金めっきした電極で挟んだ。次に、この金めっき電極の両端に荷重(5kgf/cm2または20kgf/cm2)を加え、続いて電極間に一定の電流を流した。このとき生じるカーボンペーパーとセパレータ用シート材と間の電圧降下を測定し、この結果に基づいて接触抵抗を測定した。なお、得られた抵抗値は狭持した両面の接触抵抗を合算した値となるため、これを2で除してガス拡散電極層片面あたりの接触抵抗値を求め、この値で評価した。
電流値および電圧降下は、デジタルマルチメータ((株)東陽テクニカ製 KEITHLEY 2001)を用いて測定した。
セパレータ用シート材を90℃、pH2のH2SO4に96時間浸漬し、十分に水洗し乾燥させた後に、前述の接触抵抗測定を行った。耐食性が良好でない場合には、セパレータ用シート材の表面には不動態皮膜が成長するため、浸漬前と比較し接触抵抗が上昇する。
被覆させる黒鉛の面間隔測定は2θ/θスキャン法で測定し、X線回折測定装置((株)リガク製 RINT 2000)を用いて学振法117(炭素材料の格子定数および結晶子の大きさ測定法(改正案)04/07/08)に従い、標準Siを20質量%添加して、ベースライン補正、プロファイル補正等を施し、正確な002面間隔(d002)、すなわちC面間隔を算出した。なお、計算には、(株)リアライズ理工センター製 Carbon-X Ver1.4.2 炭素材料X線回折データ解析プログラムを活用した。
評価に用いた固体高分子形燃料単セル電池は、米国Electrochem社製市販電池セルEFC50を改造して用いた。
表面処理前のセパレータ用シート材に対して、図1に示す形状で両面(アノード側、カソード側)にプレス加工を行って溝幅2mm、溝深さ1mmのガス流路を形成して、セパレータとした。その後、実施例に示す表面処理法を行った後、このセパレータを用いて固体高分子形単セル電池を組み立てた。実施例においては単セルで評価を行った。多セル積層した状態では、積層の技術の善し悪しが評価結果に反映されるためである。
水素ガス、空気の電池への導入ガス圧は0.04~0.20barで調整した。セル性能評価は、単セル電圧で0.5A/cm2において0.62±0.04Vが確認できた状態を評価の開始時点とし、その後継時的に測定を行った。
(1)初期電池電圧
特性評価は、電池内に燃料ガスを流してから0.5A/cm2の出力が得られたときから単セル電池の電圧を測定し、測定開始後48時間の最も高い電池電圧を初期電池電圧と定義した。
初期電池電圧を記録した500時間後の電池電圧(0.5A/cm2の出力時)を用いて、下記の定義(一時間毎の電池電圧低下割合)で燃料電池の劣化度を定義した。
劣化度={500時間後の電池電圧(V)-初期電池電圧(V)}/500時間
セパレータ用シート材の表面に形成された導電層の密着度測定は、JIS D0202-1988に準拠して碁盤目テープ剥離試験を行った。セロハンテープ(ニチバン(株)製 CT24)を用い、指の腹でフィルムに密着させた後剥離した。判定は100マス(10×10)の内、剥離しないマス目の数で表し、導電層が剥離しない場合を100/100、完全に剥離する場合を0/100として表した。
従来の発明を確認するための試験番号1~9の評価試料を準備した手順を以下に示す。
試験番号1(市中入手SUS)
表2に示したSUS316Lステンレス鋼板(厚さ:4mm)を用いた。切削および放電加工により所定のセパレータ形状に仕上げ、試験用のセパレータを得た。
表2に示したSUS316Lステンレス鋼板(厚さ:4mm)を切削および放電加工によりセパレータ形状とした。得られたセパレータ形状を有するステンレス鋼板を、脱脂、洗浄、表面活性化、および洗浄をこの順番で行い、さらに市販のシアン金カリウム溶液を用いて単位電池の電極接触面(ガス拡散電極層との接触部)に相当する面に金めっきを施して試験用のセパレータを得た。金めっきの厚みは0.05μmであった。
表2に示した4種類のステンレス鋼板のうち316L、304および430(何れも厚さは0.15mm)を用いて、特許文献10に開示された方法を実施した。平均粒径約0.05μmのカーボンブラックをまぶしたフェルトでステンレス鋼板の表面を摺擦した。その後圧下率3%の圧延を行うことにより、ステンレス鋼板の表面にカーボンコートを行った。電池評価に用いるセパレータは、プレス成形加工により所定の形状へ加工することにより得た。
表2に示したステンレス鋼板のうち430ステンレス鋼板(厚さ0.15mmt)を用いて確認試験を実施した。ステンレス鋼板をプレス加工により所定のセパレータ形状とした。その後セパレータ形状を有するステンレス鋼板を、塩酸10質量%を含有する温度60℃溶液を用いて10秒間酸洗した。グラファィト粉末(大阪ガス製MCMB 平均粒径6μm)100重量部に対して、水分散性カーボンブラックを添加したポリオレフィン樹脂の水分散性塗料を35重量部の割合で混合させた塗料を用意した。酸洗後のステンレス鋼板の表裏面にこの塗料を30μm厚で塗布し、120℃×1分間の焼き付け処理を行って、試験用のセパレータを得た。
表2に示したステンレス鋼板のうち304ステンレス鋼板(0.15mmt)をプレス加工により、所定のセパレータ形状にした。結着材の材料の一つとして、スチレン-ブタジエン共重合体(スチレン-ブタジエンのランダム共重合体のエマルション(固形分40重量%))樹脂を用意した。グラファイト粉末(大阪ガス製MCMB 平均粒径6μm)80質量部に対してカーボンブラックを20質量部の割合で混合させた粉末を調製した。このカーボンと黒鉛とからなる粉末60質量部に対して上記のスチレン-ブタジエン共重合体のエマルションを40質量部の割合で混合し、この混合物を混練して塗料とした。セパレータ形状を有するステンレス鋼板に、得られた塗料をドクターブレードにて塗布した。塗料層を有するステンレス鋼板を150℃で15分乾燥して、試験用のセパレータを得た。
表2に示したステンレス鋼板のうち316Lステンレス鋼板(厚さ:0.15mm)をプレス加工により、セパレータ形状に成形した。グラファイトをターゲット材とするイオンビーム蒸着法によって、セパレータ形状を有するステンレス鋼板に非晶質炭素を蒸着し、試験用のセパレータを得た。
Fe3+を20g/l含む液温50℃の塩化第二鉄水溶液を準備した。アノード電流密度5.0kA/m2、カソード電流密度0.2kA/m2、交番電解サイクル2.5kHz、処理時間を60秒間の条件で、316Lステンレス鋼板に対して交番電解処理を行った。処理後のステンレス鋼板をプレス加工により所定のセパレータ形状に加工して、試験用のセパレータを得た。
まず、表2に示す4種類のステンレス鋼板を切削・放電加工により、図1に示す5a、5bの形状のセパレータ形状に加工した。
(A)硫酸処理
表3に示す硫酸溶液および酸洗条件で調整を行った。
に黒鉛電極をカソード極、ステンレス鋼板をアノード極として、硫酸電解を実施した。硫酸電解処理条件を表4に示す。ステンレス鋼板を溶液に60秒浸漬した後、電解処理を開始した。
本発明例1~5(試験番号10~14)のステンレス鋼板は、5kgf/cm2の荷重を負荷させた場合の初期接触抵抗および耐食性試験後の接触抵抗がいずれも20mΩ・cm2未満であった。比較従来技術に係る試験No.1および3~9のステンレス鋼板と比べて、初期、抵および耐食性試験後のいずれについても接触抵抗が小さく、本発明に係るステンレス鋼材のほうが耐食性に優れる。試験番号2のステンレス鋼板は接触抵抗が低いものの、金めっきが高価であるため、経済性および稀少資源を大量に消費する点で問題がある。
(実施例2)
本発明の好適な範囲として、黒鉛層に含まれる黒鉛質炭素の好適な面間隔範囲を確認するために次の実験を行った。
ステンレス鋼板の表面粗さにおける望ましい範囲を確認すべく次の実験を行った。種々の表面粗さを有する素材は、ベルトグラインダーの砥粒粗さ、塩化第二鉄エッチング時間を調整することにより得た。
これに対し、Raが0.10~1.0μm範囲であれば、プレス加工時の割れを心配することなく特に良好な電池特性を得ることができる。
導電性析出物が形成される前のステンレス鋼板に対して硫酸電解処理を施す際に、対極に黒鉛質炭素を用いステンレス鋼板と摺動させることにより、導電性スマットの形成と黒鉛層の形成とを同時に行った場合の効果を検証するための実施例を示す。
ベルトグラインダーで粗面化処理を行ったステンレス鋼板を処理対象の部材とし、0.4Vの電圧を印加して導電性スマットおよび黒鉛層を形成した。得られたステンレス鋼板に対して上記の評価を行った結果を表9に示す。
(実施例5)
本発明の中でも好適な範囲を確認するため、表7に示されるように黒鉛層の形成方法が異なる評価試料を作製し、被覆された黒鉛質炭素の配向の影響を調査した。
表10における「プレス」と表記された試験番号33および38のステンレス鋼板では、表面に導電性スマットが析出したステンレス鋼板(SUS316L)におけるガス拡散電極層との接触部に対応する部分に、黒鉛粉末(中越黒鉛工業製 鱗状黒鉛 平均粒度10μm 面間隔 d=3.36Å)を配置し、150kgf/cm2の荷重でプレスすることにより、黒鉛層を形成した。
Claims (11)
- 固体高分子形燃料電池のセパレータ用ステンレス鋼材であって、
ステンレス鋼母材と、
いずれも当該ステンレス鋼母材の表面上に設けられた不動態皮膜および導電性析出物とを備え、
前記導電性析出物は、前記不動態皮膜を貫通しており、前記ステンレス鋼母材を起源とする物質を含む、ステンレス鋼材。 - 前記導電性析出物が、O、S、Fe、CrおよびCを構成元素として含み、多結晶体である請求項1に記載のステンレス鋼材。
- 非金属導電性物質からなる導電層が前記不動態皮膜の表面に設けられ、当該導電層は前記導電性析出物を介して前記ステンレス鋼母材と電気的に接続される、請求項1または2に記載のステンレス鋼材。
- 前記非金属導電性物質が黒鉛質炭素を含む請求項3に記載のステンレス鋼材。
- 前記不動態皮膜表面に設けられた黒鉛質炭素の面間隔がd002≦3.390Åである請求項4に記載のステンレス鋼材。
- 前記不動態皮膜の表面に設けられた黒鉛質炭素の結晶について広角X線回折測定することにより得られる原子面の回折線のピーク強度を比較したときに、(110)原子面の回折線のピーク強度の(004)原子面の回折線のピーク強度に対する比率が0.1未満である、請求項5に記載のステンレス鋼材。
- 前記導電層が、前記不動態皮膜の表面と前記導電性析出物の表面とからなる表面に対して黒鉛質炭素を含む部材を摺動させることにより形成されたものである請求項4から6のいずれかに記載のステンレス鋼材。
- 前記不動態皮膜の表面と導電性析出物の表面とからなる表面の平均表面粗さがRaとして0.10μm以上である請求項7に記載のステンレス鋼材。
- 前記導電性析出物および前記導電層が、前記ステンレス鋼母材と前記不動態皮膜とからなるステンレス鋼基材を、硫酸イオンを含む酸性溶液中で電解処理すると同時に、この電解処理において対極として機能する黒鉛質炭素を含む部材を前記対象部材上で摺動させることにより形成されたものである、請求項4から6のいずれかに記載のステンレス鋼材。
- 前記ステンレス鋼基材の表面の平均表面粗さがRaとして0.10μm以上である請求項9に記載のステンレス鋼材。
- 請求項1から9のいずれかに記載されるステンレス鋼材から得られたセパレータを備える固体高分子型燃料電池。
Priority Applications (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CN200980148903.1A CN102239593B (zh) | 2008-10-07 | 2009-10-07 | 固体高分子型燃料电池的隔板用不锈钢板及使用该钢板的固体高分子型燃料电池 |
KR1020117010453A KR101387767B1 (ko) | 2008-10-07 | 2009-10-07 | 고체 고분자형 연료 전지의 세퍼레이터용 스테인리스강판 및 그것을 이용한 고체 고분자형 연료 전지 |
EP09819228.9A EP2343763B1 (en) | 2008-10-07 | 2009-10-07 | Sheet stainless steel for separators in solid polymer fuel cells, and solid polymer fuel cells using the same |
US13/080,937 US9680162B2 (en) | 2008-10-07 | 2011-04-06 | Stainless steel sheet for a separator for a solid polymer fuel cell and a solid polymer fuel cell employing the separator |
Applications Claiming Priority (6)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2008260873 | 2008-10-07 | ||
JP2008-260873 | 2008-10-07 | ||
JP2008-292367 | 2008-11-14 | ||
JP2008292367 | 2008-11-14 | ||
JP2009-233511 | 2009-10-07 | ||
JP2009233511A JP5338607B2 (ja) | 2008-10-07 | 2009-10-07 | 固体高分子型燃料電池のセパレータ用ステンレス鋼板およびそれを用いた固体高分子型燃料電池 |
Related Child Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US13/080,937 Continuation US9680162B2 (en) | 2008-10-07 | 2011-04-06 | Stainless steel sheet for a separator for a solid polymer fuel cell and a solid polymer fuel cell employing the separator |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2010041694A1 true WO2010041694A1 (ja) | 2010-04-15 |
Family
ID=42100642
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/JP2009/067512 WO2010041694A1 (ja) | 2008-10-07 | 2009-10-07 | 固体高分子型燃料電池のセパレータ用ステンレス鋼板およびそれを用いた固体高分子型燃料電池 |
Country Status (6)
Country | Link |
---|---|
US (1) | US9680162B2 (ja) |
EP (1) | EP2343763B1 (ja) |
JP (1) | JP5338607B2 (ja) |
KR (1) | KR101387767B1 (ja) |
CN (1) | CN102239593B (ja) |
WO (1) | WO2010041694A1 (ja) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20150167134A1 (en) * | 2012-05-16 | 2015-06-18 | Bayerische Motoren Werke Aktiengesellschaft | Reduced Cost Steel for Hydrogen Technology with High Resistance to Hydrogen-Induced Embrittlement |
WO2017051810A1 (ja) * | 2015-09-25 | 2017-03-30 | 新日鐵住金株式会社 | 固体高分子形燃料電池用カーボンセパレータ、固体高分子形燃料電池セル、および固体高分子形燃料電池 |
CN112665954A (zh) * | 2020-12-02 | 2021-04-16 | 中国科学院金属研究所 | 一种多相奥氏体不锈钢焊缝金属金相腐蚀方法 |
Families Citing this family (16)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE102012104254A1 (de) * | 2011-11-02 | 2013-05-02 | Bayerische Motoren Werke Aktiengesellschaft | Kostenreduzierter Stahl für die Wasserstofftechnik mit hoher Beständigkeit gegen wasserstoffinduzierte Versprödung |
JP5201256B1 (ja) | 2011-11-18 | 2013-06-05 | 新日鐵住金株式会社 | 固体高分子型燃料電池セパレータ用チタン材並びにその製造方法およびそれを用いた固体高分子型燃料電池 |
US9537158B2 (en) * | 2011-11-30 | 2017-01-03 | Korea Institute Of Science And Technology | Oxidation resistant ferritic stainless steel including copper-containing spinel-structured oxide, method of manufacturing the steel, and fuel cell interconnect using the steel |
KR102073454B1 (ko) * | 2013-06-13 | 2020-02-04 | 도요 고한 가부시키가이샤 | 금도금 피복 스테인리스재 및 금도금 피복 스테인리스재의 제조 방법 |
JP6163934B2 (ja) * | 2013-07-18 | 2017-07-19 | トヨタ車体株式会社 | 燃料電池のセパレータの製造方法 |
CN105556002B (zh) * | 2013-09-20 | 2018-03-20 | 东洋钢钣株式会社 | 镀金属覆盖不锈钢材料以及镀金属覆盖不锈钢材料的制造方法 |
JP6706067B2 (ja) | 2013-10-28 | 2020-06-03 | 東洋鋼鈑株式会社 | 合金めっき被覆材料、および合金めっき被覆材料の製造方法 |
JP6574568B2 (ja) * | 2014-12-12 | 2019-09-11 | 東洋鋼鈑株式会社 | 金属めっき被覆ステンレス材の製造方法 |
ES2734051T3 (es) * | 2015-06-05 | 2019-12-04 | Nippon Steel Corp | Acero inoxidable austenítico |
KR101742088B1 (ko) * | 2015-12-23 | 2017-06-01 | 주식회사 포스코 | 친수성 및 접촉저항이 향상된 고분자 연료전지 분리판용 스테인리스강 및 이의 제조 방법 |
JP6810536B2 (ja) * | 2016-04-25 | 2021-01-06 | 臼井国際産業株式会社 | 金属材およびその製造方法 |
WO2021059678A1 (ja) * | 2019-09-27 | 2021-04-01 | 本田技研工業株式会社 | 金属塗装方法 |
KR102286367B1 (ko) * | 2019-11-11 | 2021-08-05 | 주식회사 포스코 | 고분자 연료전지 분리판용 스테인리스강의 제조방법 |
EP4080623A4 (en) * | 2019-12-19 | 2023-01-25 | Posco | STAINLESS STEEL HAVING EXCELLENT SURFACE ELECTRICAL CONDUCTIBILITY FOR FUEL CELL SEPARATOR AND METHOD OF MANUFACTURING THEREOF |
JP7453800B2 (ja) | 2020-02-04 | 2024-03-21 | 日鉄ケミカル&マテリアル株式会社 | ステンレス鋼板、燃料電池用セパレータ、燃料電池セル、及び燃料電池スタック |
KR102497442B1 (ko) * | 2020-11-25 | 2023-02-08 | 주식회사 포스코 | 접촉저항이 향상된 고분자 연료전지 분리판용 오스테나이트계 스테인리스강 및 그 제조 방법 |
Citations (15)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH10228914A (ja) | 1997-02-13 | 1998-08-25 | Aisin Takaoka Ltd | 燃料電池用セパレータ |
WO1999019927A1 (en) | 1997-10-14 | 1999-04-22 | Nisshin Steel Co., Ltd. | Separator for low temperature type fuel cell and method of production thereof |
JPH11121018A (ja) | 1997-10-14 | 1999-04-30 | Nisshin Steel Co Ltd | 低温型燃料電池用セパレータ |
JPH11345618A (ja) | 1998-06-03 | 1999-12-14 | Nisshin Steel Co Ltd | 固体高分子型燃料電池用塗装金属セパレータ材料 |
WO2000001025A1 (fr) | 1998-06-30 | 2000-01-06 | Matsushita Electric Industrial Co., Ltd. | Pile a combustible electrolytique en polymere solide |
JP2000067881A (ja) | 1998-08-24 | 2000-03-03 | Honda Motor Co Ltd | 燃料電池用セパレータ |
JP2000323152A (ja) * | 1999-05-12 | 2000-11-24 | Nisshin Steel Co Ltd | ステンレス鋼製低温型燃料電池用セパレータ及びその製造方法 |
JP2001032056A (ja) * | 1999-07-22 | 2001-02-06 | Sumitomo Metal Ind Ltd | 通電部品用ステンレス鋼および固体高分子型燃料電池 |
WO2001018895A1 (fr) | 1999-09-02 | 2001-03-15 | Matsushita Electric Industrial Co., Ltd. | Pile a combustible a electrolyte polymere |
JP2002042828A (ja) * | 2000-07-25 | 2002-02-08 | Honda Motor Co Ltd | 燃料電池用セパレータ |
WO2002023654A1 (en) | 2000-09-12 | 2002-03-21 | Nisshin Steel Co., Ltd. | Separator for low-temperature type fuel cell and production method therefor |
JP3365385B2 (ja) | 2000-01-31 | 2003-01-08 | 住友金属工業株式会社 | 固体高分子型燃料電池のセパレータ用ステンレス鋼材の製造方法 |
WO2003044888A1 (fr) | 2001-11-21 | 2003-05-30 | Hitachi Powdered Metals Co.,Ltd. | Materiau de revetement pour separateur de pile a combustible |
JP2004124197A (ja) * | 2002-10-04 | 2004-04-22 | Jfe Steel Kk | 固体高分子型燃料電池セパレータ用ステンレス鋼とその製造方法および固体高分子型燃料電池 |
JP2004269969A (ja) * | 2003-03-10 | 2004-09-30 | Jfe Steel Kk | 固体高分子型燃料電池用セパレータおよびその製造方法 |
Family Cites Families (20)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5789086A (en) * | 1990-03-05 | 1998-08-04 | Ohmi; Tadahiro | Stainless steel surface having passivation film |
DE69812017T2 (de) * | 1997-09-19 | 2003-12-11 | Matsushita Electric Ind Co Ltd | Nichtwässrige Sekundär Batterie und ihre Anode |
JP3980153B2 (ja) * | 1998-03-09 | 2007-09-26 | 日新製鋼株式会社 | 低温型燃料電池用セパレータ |
KR100361548B1 (ko) * | 1999-04-19 | 2002-11-21 | 스미토모 긴조쿠 고교 가부시키가이샤 | 고체고분자형 연료전지용 스텐레스 강재 |
KR100436456B1 (ko) * | 1999-09-17 | 2004-06-22 | 마쯔시다덴기산교 가부시키가이샤 | 고분자 전해질형 연료전지 |
JP2001283880A (ja) * | 2000-03-30 | 2001-10-12 | Nisshin Steel Co Ltd | 低温型燃料電池用セパレータ及びその製造方法 |
DE10194846B4 (de) * | 2000-11-10 | 2008-02-28 | Honda Giken Kogyo K.K. | Verfahren zur Oberflächenbehandlung eines rostfreien Stahlprodukts für eine Brennstoffzelle |
CA2413558C (en) * | 2001-12-05 | 2007-06-05 | Honda Giken Kogyo Kabushiki Kaisha | Fuel cell metallic separator and method for manufacturing same |
DE10297507T5 (de) * | 2001-12-07 | 2004-11-25 | Honda Giken Kogyo K.K. | Metallischer Separator für Brennstoffzelle und Herstellungsverfahren für denselben |
WO2003052848A1 (en) * | 2001-12-18 | 2003-06-26 | Honda Giken Kogyo Kabushiki Kaisha | Method of producing fuel cell-use separator and device for producing it |
JP4147925B2 (ja) * | 2002-12-04 | 2008-09-10 | トヨタ自動車株式会社 | 燃料電池用セパレータ |
JP2005243595A (ja) * | 2003-03-31 | 2005-09-08 | Isamu Uchida | 固体高分子型燃料電池用セパレータおよびそれを用いた固体高分子型燃料電池 |
US7396559B2 (en) * | 2003-08-11 | 2008-07-08 | General Motors Corporation | Method of making an electrically conductive element for use in a fuel cell |
TW200522425A (en) * | 2003-12-24 | 2005-07-01 | Showa Denko Kk | Separator for fuel cell and its manufacturing method |
CA2714829C (en) * | 2004-03-18 | 2016-02-09 | Jfe Steel Corporation | Metallic material for conductive member, separator for fuel cell using the same, and fuel cell using the separator |
WO2005124910A1 (ja) * | 2004-06-21 | 2005-12-29 | Kabushiki Kaisha Riken | オーステナイト系ステンレス鋼を基材とする燃料電池用セパレータ |
JP2007027032A (ja) * | 2005-07-21 | 2007-02-01 | Nisshin Steel Co Ltd | 固体高分子型燃料電池用ステンレス鋼製セパレータ及び燃料電池 |
JP4689391B2 (ja) * | 2005-07-28 | 2011-05-25 | Jfeケミカル株式会社 | リチウムイオン二次電池負極材料用黒鉛材料の製造方法 |
US9103041B2 (en) * | 2006-12-28 | 2015-08-11 | Posco | Method for improving surface properties of the stainless steels for bipolar plate of polymer electrolyte membrane fuel cell |
KR100777123B1 (ko) * | 2007-04-18 | 2007-11-19 | 현대하이스코 주식회사 | 연료전지용 스테인리스강 분리판 및 그 제조방법 |
-
2009
- 2009-10-07 EP EP09819228.9A patent/EP2343763B1/en active Active
- 2009-10-07 WO PCT/JP2009/067512 patent/WO2010041694A1/ja active Application Filing
- 2009-10-07 JP JP2009233511A patent/JP5338607B2/ja active Active
- 2009-10-07 CN CN200980148903.1A patent/CN102239593B/zh active Active
- 2009-10-07 KR KR1020117010453A patent/KR101387767B1/ko active IP Right Grant
-
2011
- 2011-04-06 US US13/080,937 patent/US9680162B2/en active Active
Patent Citations (15)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH10228914A (ja) | 1997-02-13 | 1998-08-25 | Aisin Takaoka Ltd | 燃料電池用セパレータ |
WO1999019927A1 (en) | 1997-10-14 | 1999-04-22 | Nisshin Steel Co., Ltd. | Separator for low temperature type fuel cell and method of production thereof |
JPH11121018A (ja) | 1997-10-14 | 1999-04-30 | Nisshin Steel Co Ltd | 低温型燃料電池用セパレータ |
JPH11345618A (ja) | 1998-06-03 | 1999-12-14 | Nisshin Steel Co Ltd | 固体高分子型燃料電池用塗装金属セパレータ材料 |
WO2000001025A1 (fr) | 1998-06-30 | 2000-01-06 | Matsushita Electric Industrial Co., Ltd. | Pile a combustible electrolytique en polymere solide |
JP2000067881A (ja) | 1998-08-24 | 2000-03-03 | Honda Motor Co Ltd | 燃料電池用セパレータ |
JP2000323152A (ja) * | 1999-05-12 | 2000-11-24 | Nisshin Steel Co Ltd | ステンレス鋼製低温型燃料電池用セパレータ及びその製造方法 |
JP2001032056A (ja) * | 1999-07-22 | 2001-02-06 | Sumitomo Metal Ind Ltd | 通電部品用ステンレス鋼および固体高分子型燃料電池 |
WO2001018895A1 (fr) | 1999-09-02 | 2001-03-15 | Matsushita Electric Industrial Co., Ltd. | Pile a combustible a electrolyte polymere |
JP3365385B2 (ja) | 2000-01-31 | 2003-01-08 | 住友金属工業株式会社 | 固体高分子型燃料電池のセパレータ用ステンレス鋼材の製造方法 |
JP2002042828A (ja) * | 2000-07-25 | 2002-02-08 | Honda Motor Co Ltd | 燃料電池用セパレータ |
WO2002023654A1 (en) | 2000-09-12 | 2002-03-21 | Nisshin Steel Co., Ltd. | Separator for low-temperature type fuel cell and production method therefor |
WO2003044888A1 (fr) | 2001-11-21 | 2003-05-30 | Hitachi Powdered Metals Co.,Ltd. | Materiau de revetement pour separateur de pile a combustible |
JP2004124197A (ja) * | 2002-10-04 | 2004-04-22 | Jfe Steel Kk | 固体高分子型燃料電池セパレータ用ステンレス鋼とその製造方法および固体高分子型燃料電池 |
JP2004269969A (ja) * | 2003-03-10 | 2004-09-30 | Jfe Steel Kk | 固体高分子型燃料電池用セパレータおよびその製造方法 |
Non-Patent Citations (3)
Title |
---|
"Report on Fuel Cell Automobiles", 2004, JAPAN AUTOMOTIVE RESEARCH LABORATORY, pages: 214 |
See also references of EP2343763A4 |
TITANIUM, vol. 54, no. 4, pages 259 |
Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20150167134A1 (en) * | 2012-05-16 | 2015-06-18 | Bayerische Motoren Werke Aktiengesellschaft | Reduced Cost Steel for Hydrogen Technology with High Resistance to Hydrogen-Induced Embrittlement |
US10513764B2 (en) * | 2012-05-16 | 2019-12-24 | Bayerische Motoren Werke Aktiengesellschaft | Reduced cost steel for hydrogen technology with high resistance to hydrogen-induced embrittlement |
WO2017051810A1 (ja) * | 2015-09-25 | 2017-03-30 | 新日鐵住金株式会社 | 固体高分子形燃料電池用カーボンセパレータ、固体高分子形燃料電池セル、および固体高分子形燃料電池 |
JPWO2017051810A1 (ja) * | 2015-09-25 | 2018-02-08 | 新日鐵住金株式会社 | 固体高分子形燃料電池用カーボンセパレータ、固体高分子形燃料電池セル、および固体高分子形燃料電池 |
US10622643B2 (en) | 2015-09-25 | 2020-04-14 | Nippon Steel Corporation | Carbon separator for solid polymer fuel cell, solid polymer fuel cell, and solid polymer fuel cell stack |
CN112665954A (zh) * | 2020-12-02 | 2021-04-16 | 中国科学院金属研究所 | 一种多相奥氏体不锈钢焊缝金属金相腐蚀方法 |
CN112665954B (zh) * | 2020-12-02 | 2023-04-11 | 中国科学院金属研究所 | 一种多相奥氏体不锈钢焊缝金属金相腐蚀方法 |
Also Published As
Publication number | Publication date |
---|---|
JP5338607B2 (ja) | 2013-11-13 |
KR20110084224A (ko) | 2011-07-21 |
US20110250522A1 (en) | 2011-10-13 |
CN102239593A (zh) | 2011-11-09 |
KR101387767B1 (ko) | 2014-04-21 |
EP2343763A4 (en) | 2013-01-23 |
CN102239593B (zh) | 2014-03-12 |
EP2343763B1 (en) | 2017-09-06 |
US9680162B2 (en) | 2017-06-13 |
EP2343763A1 (en) | 2011-07-13 |
JP2010138487A (ja) | 2010-06-24 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
JP5338607B2 (ja) | 固体高分子型燃料電池のセパレータ用ステンレス鋼板およびそれを用いた固体高分子型燃料電池 | |
JP5343731B2 (ja) | 固体高分子形燃料電池のセパレータ用ステンレス鋼材およびそれを用いた固体高分子形燃料電池 | |
US10934615B2 (en) | Method of metallic component surface modification for electrochemical applications | |
Tian et al. | Corrosion resistance and interfacial contact resistance of TiN coated 316L bipolar plates for proton exchange membrane fuel cell | |
KR20100066471A (ko) | 고체 산화물 연료 전지 인터커넥션을 위한 보호성 산화물 코팅 | |
Li et al. | Investigation of single-layer and multilayer coatings for aluminum bipolar plate in polymer electrolyte membrane fuel cell | |
CN107408713B (zh) | 固体高分子型燃料电池的隔板用金属板 | |
JP6414369B1 (ja) | 燃料電池のセパレータ用鋼板の基材ステンレス鋼板およびその製造方法 | |
WO2014134019A1 (en) | Corrosion resistance metallic components for batteries | |
WO2015194356A1 (ja) | 固体高分子形燃料電池のセパレータ用チタン材、これを用いたセパレータ、およびこれを備えた固体高分子形燃料電池 | |
KR100917610B1 (ko) | 고체산화물 연료전지용 금속연결재의 코팅방법 | |
WO2016140306A1 (ja) | チタン材、セパレータ、および固体高分子形燃料電池、ならびにチタン材の製造方法 | |
JP2015138696A (ja) | 固体高分子形燃料電池のセパレータ用チタン材 | |
CN113328111B (zh) | 一种具有铬基氮化物复合镀层的不锈钢双极板及其制备方法 | |
JP6753165B2 (ja) | 固体高分子形燃料電池のセパレータ用チタン材、およびそれを用いたセパレータ | |
JP5077207B2 (ja) | ステンレス鋼材 | |
JP2017088955A (ja) | 固体高分子形燃料電池のセパレータ用チタン材、およびそれを用いたセパレータ | |
KR100867819B1 (ko) | 연료전지용 금속분리판의 표면층 및 이의 형성방법 | |
JP2023122178A (ja) | 燃料電池用セパレータの製造方法 | |
JP2012212644A (ja) | 燃料電池セパレータの製造方法 | |
JP2010086897A (ja) | 燃料電池セパレータ及び燃料電池セパレータの製造方法 |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
WWE | Wipo information: entry into national phase |
Ref document number: 200980148903.1 Country of ref document: CN |
|
121 | Ep: the epo has been informed by wipo that ep was designated in this application |
Ref document number: 09819228 Country of ref document: EP Kind code of ref document: A1 |
|
NENP | Non-entry into the national phase |
Ref country code: DE |
|
REEP | Request for entry into the european phase |
Ref document number: 2009819228 Country of ref document: EP |
|
WWE | Wipo information: entry into national phase |
Ref document number: 2009819228 Country of ref document: EP |
|
ENP | Entry into the national phase |
Ref document number: 20117010453 Country of ref document: KR Kind code of ref document: A |