JP2009230964A - Catalyst layer transcription sheet, manufacturing method of electrolyte membrane-catalyst layer assembly using the same, manufacturing method of electrolyte membrane-electrode assembly, and manufacturing method of solid polymer fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a catalyst layer transcription sheet capable of improving yield by reducing transcription film peeling-off failure at the time of catalyst layer transcription, to provide a manufacturing method of an electrolyte membrane-catalyst layer assembly using the same, to provide a manufacturing method of the electrolyte membrane-electrode assembly, and to provide a manufacturing method of a solid polymer fuel cell. <P>SOLUTION: Two catalyst layer transcription sheets 1 each including a base material 2 having a sheet shape gripping part 22 which is connected to a part of outer periphery of the base material body 21 and is folded so as to be stacked on an upper surface of the base material body 21, and a catalyst layer 3 formed on an under surface of the base material body 21, are prepared. The catalyst layers 3 of the transcription sheets 1 are transcripted onto both surfaces of an electrolyte layer, then the base materials 2 are peeled from the catalyst layers 3 while gripping the gripping parts 22 to form the electrolyte membrane-catalyst layer assembly. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a catalyst layer transfer sheet for transferring a catalyst layer, a method for producing an electrolyte membrane-catalyst layer assembly using the same, a method for producing an electrolyte membrane-electrode assembly, and a polymer electrolyte fuel cell It is related with the manufacturing method.

  A fuel cell is an electrochemical system in which electrodes are arranged on both sides of an electrolyte and generates electricity by an electrochemical reaction between hydrogen and oxygen, and only water is generated during power generation. Thus, unlike the conventional internal combustion engine, it is expected to spread as a next-generation clean energy system because it does not generate environmental load gas such as carbon dioxide. In particular, the polymer electrolyte fuel cell has a low operating temperature and low electrolyte resistance. In addition, it uses a highly active catalyst, so it can obtain high output even in a small size. Is expected to be put to practical use.

This solid polymer fuel cell uses a solid polymer electrolyte membrane having proton conductivity, and a catalyst layer and a gas diffusion layer are sequentially laminated on both surfaces of the electrolyte membrane. And it has the structure which has arrange | positioned the gasket so that the circumference | surroundings of the electrode which consists of this catalyst layer and a gas diffusion layer may be enclosed, and also this was pinched | interposed with the separator. (For example, refer to FIG. 1 of Patent Document 1). One method for forming the catalyst layer on the electrolyte membrane is to use a catalyst layer transfer sheet. In this catalyst layer forming method using the catalyst layer transfer sheet, first, two catalyst layer transfer sheets each having a catalyst layer formed on a substrate are prepared, and the catalyst layer is placed so that the catalyst layer faces the electrolyte membrane side. Are disposed on both sides of the electrolyte membrane. Then, the catalyst layer is transferred onto the electrolyte membrane by applying heat press or the like from the back side of each catalyst layer transfer sheet, and then the catalyst layer is formed on the electrolyte membrane by peeling only the base material (patent) Reference 1).
JP 2006-286560 A

  By the way, in the method for forming a catalyst layer using the catalyst layer transfer sheet as described above, when the substrate is peeled off, the catalyst layer is not transferred onto the electrolyte membrane and remains on the substrate side together with the substrate. May be peeled off. When the catalyst layer is peeled off together with the substrate without being transferred to the electrolyte membrane in this way, it is treated as a defective product called so-called peeling failure.

  Therefore, the present invention is a catalyst layer transfer sheet that can reduce the separation failure and improve the yield, a method for producing an electrolyte membrane-catalyst layer assembly using the same, a method for producing an electrolyte membrane-electrode assembly, It is another object of the present invention to provide a method for producing a polymer electrolyte fuel cell.

  The catalyst layer transfer sheet according to the present invention is made to solve the above problems, and is connected to a sheet-like base body and a part of the outer peripheral edge of the base body, and The base material which has the sheet-like holding part folded so that it may be laminated | stacked on one surface, and the catalyst layer formed in the other surface of the said base-material main body are provided.

  In general, many peeling defects occur at the part where the substrate starts to peel. This is considered to be because the catalyst layer damaged when peeling the substrate is peeled off and peeled off together with the substrate. On the other hand, since the base material of the catalyst layer transfer sheet according to the present invention has a grip portion formed on the base material body, the base material can be peeled off by grasping and pulling the grip portion. The substrate can be peeled without damaging the catalyst layer. As described above, the present invention can prevent the catalyst layer from being damaged, so that the occurrence of defective peeling can be suppressed and thus the yield can be improved. Moreover, when the said holding | grip part is extended outward from the said base-material main-body part, when performing a hot press etc., there exists a possibility that a holding | grip part may damage an electrolyte membrane or may adhere to an electrolyte membrane. On the other hand, the grip portion of the catalyst layer transfer sheet according to the present invention is folded so as to be laminated on one surface of the base body, so that the electrolyte membrane is scratched or stuck to the electrolyte membrane. Can be prevented. In addition, although the said holding part is connected with a part of outer periphery of a base-material main body, the base-material main body and the holding part may be an integral thing comprised from one member, The separate thing comprised from the separate member may be sufficient.

  The catalyst layer transfer sheet can have various configurations. For example, it is preferable that the grip portion has the same shape and the same area as the base body and is formed so as to cover the entire base body. By comprising in this way, the pressure which acts on the surface of a catalyst layer and an electrolyte membrane can be made constant in the press process for transferring the catalyst layer of a catalyst layer transfer sheet to an electrolyte membrane.

  Moreover, it is preferable that the base material body has a rectangular shape in plan view, and the gripping portion is connected to the base material body at the corners of the base material body. By comprising in this way, since a base material begins to peel from a corner | angular part when peeling a base material, a peeling defect can be suppressed more.

  Moreover, it is preferable that the said holding | grip part is adhere | attached on one side of a base-material main body so that peeling is possible in the folded state. By comprising in this way, since a holding part hold | maintains the folded state, it is preferable from the surface of handling.

  Moreover, the manufacturing method of the electrolyte membrane-catalyst layer assembly according to the present invention has been made in order to solve the above-mentioned problems, and includes a step of preparing two of the catalyst layer transfer sheets described above, and an electrolyte. A step of preparing a membrane, a step of arranging each catalyst layer transfer sheet with the catalyst layer facing the electrolyte membrane so as to sandwich the electrolyte membrane between the catalyst layer transfer sheets, and the catalyst layer transfer sheet A step of transferring the catalyst layer to both surfaces of the electrolyte membrane, and a step of peeling the base material by grasping the grip portion.

  According to this manufacturing method, when the catalyst layer is transferred to the electrolyte membrane and the substrate is peeled off, the substrate can be peeled by grasping and pulling the grip portion, thereby preventing the catalyst layer from being damaged. As a result, the separation failure can be suppressed and the yield can be improved.

  Moreover, the manufacturing method of the electrolyte membrane-electrode assembly which concerns on this invention was made | formed in order to solve the said subject, The manufacturing method of the electrolyte membrane-catalyst layer assembly mentioned above, and on each said catalyst layer Forming a gas diffusion layer.

  According to this manufacturing method, since the manufacturing method of the electrolyte membrane-catalyst layer assembly described above is included, the catalyst layer can be prevented from being damaged when the base material is peeled off, thereby suppressing the peeling failure and the yield. Can be improved.

  In addition, a method for producing a polymer electrolyte fuel cell according to the present invention has been made in order to solve the above-described problems. The method for producing an electrolyte membrane-electrode assembly described above, and the electrolyte membrane-electrode assembly are described above. And a step of installing a separator so as to sandwich the electrolyte membrane-electrode assembly.

  According to this manufacturing method, since the manufacturing method of the electrolyte membrane-catalyst layer assembly described above is included, the catalyst layer can be prevented from being damaged when the base material is peeled off, thereby suppressing the peeling failure and the yield. Can be improved.

  According to the present invention, it is possible to suppress the peeling failure and improve the yield.

  Hereinafter, an embodiment of a catalyst layer transfer sheet according to the present invention will be described with reference to the drawings. FIG. 1 is a front view of the catalyst layer transfer sheet, and FIG. 2 is a plan view of the catalyst layer transfer sheet.

  As shown in FIGS. 1 and 2, the catalyst layer transfer sheet 1 includes a base material 2 that is rectangular and sheet-like in plan view, and a catalyst layer 3 formed on the lower surface of the base material 2. The substrate 2 includes a substrate body 21 having a rectangular shape and a sheet shape in plan view, and a grip portion 22 having the same shape and the same area as the substrate body 21. The gripping part 22 is laminated on the base material body 21 so as to cover the whole base material body 21, and the base material body 21 and the gripping part 22 are connected on the right side. The catalyst layer 3 is formed on the entire lower surface of the base body 21. The base body 21 and the grip portion 22 can be connected using various methods. For example, the base body 21 and the grip portion 22 can be bonded by adhesion, fusion, laser bonding, ultrasonic welding, or the like. Can be linked.

  Examples of the material of the base body 21 constituting the base 2 include, for example, polyimide, polyethylene terephthalate, polypalvanic acid aramid, polyamide (nylon), polysulfone, polyethersulfone, polyphenylene sulfide, polyether etherketone, polyetherimide. And polymer films such as polyarylate and polyethylene naphthalate. Further, heat resistance of ethylene tetrafluoroethylene copolymer (ETFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroperfluoroalkyl vinyl ether copolymer (PFA), polytetrafluoroethylene (PTFE), etc. Resin can also be used. Further, in addition to the polymer film, coated paper such as art paper, coated paper, and lightweight coated paper, and non-coated paper such as notebook paper and copy paper may be used. The base body 2 is preferably a polymer film that is inexpensive and easily available, and more preferably polyethylene terephthalate.

  Moreover, as the material of the holding part 22 which comprises the base material 2, the same thing as the base-material main body 21 mentioned above can be mentioned, However Since the catalyst layer 3 is not formed in the holding part 22, the coating film of a catalyst layer There is no need to consider formation and peelability, various materials other than the above-mentioned materials can be used, and they have heat resistance and dimensional stability so as not to be deformed or contracted by hot pressing, As will be described later, it is preferable to use a material having mechanical strength that does not break when the gripping portion 22 is gripped and lifted upward. The combined thickness of the base body 21 and the gripping portion 22 is usually about 6 to 100 μm, preferably about 10 to 30 μm from the viewpoints of handleability and economy.

  The material of the catalyst layer 3 is a known platinum-containing catalyst layer (cathode catalyst and anode catalyst). Specifically, the catalyst layer 3 contains carbon particles supporting catalyst particles and a hydrogen ion conductive polymer electrolyte. Examples of the catalyst particles include platinum and platinum compounds. Examples of the platinum compound include an alloy of platinum and at least one metal selected from the group consisting of ruthenium, palladium, nickel, molybdenum, iridium, iron, cobalt, and the like. In general, the catalyst particles contained in the cathode catalyst layer are platinum, and the catalyst particles contained in the anode catalyst layer are an alloy of the metal and platinum. Moreover, as a hydrogen ion conductive polymer electrolyte, the same material as what is used for the electrolyte membrane 4 mentioned later can be used. In addition, it is preferable that the film thickness of the catalyst layer 3 is 5-100 micrometers, and it is more preferable that it is 10-50 micrometers.

  Next, the manufacturing method of the catalyst layer transfer sheet 1 will be described. First, the above-described carbon particles supporting the catalyst particles and the hydrogen ion conductive polymer electrolyte are mixed and dispersed in an appropriate solvent to prepare a catalyst paste. . And according to a well-known method, a catalyst paste is apply | coated on the sheet | seat used as the origin of the base-material main body 21 so that the catalyst layer 3 formed may become a desired film thickness. Examples of the method for applying the catalyst paste include known coating methods such as screen printing, spray coating, die coating, and knife coating. And after applying a catalyst paste, the catalyst layer 3 is formed on a sheet | seat by drying at predetermined temperature and time. A drying temperature is about 40-100 degreeC normally, Preferably it is about 60-80 degreeC. Although depending on the drying temperature, the drying time is usually about 5 minutes to 2 hours, preferably about 10 minutes to 1 hour. The base material body 21 on which the catalyst layer 3 is formed is produced by die-cutting the catalyst layer transfer sheet thus formed. And the holding part 22 which consists of the material mentioned above is prepared, one side of the holding part 22 is connected to the right side of the base body 21 by adhesion, fusion, laser bonding, ultrasonic welding, etc., and the catalyst layer transfer sheet 1. Form.

  Examples of the solvent used in preparing the catalyst paste include various alcohols, various ethers, various dialkyl sulfoxides, water, or a mixture thereof. Of these, alcohols are preferable. Examples of alcohols include monohydric alcohols having 1 to 4 carbon atoms such as methanol, ethanol, n-propanol, isopropanol, n-butanol, and tert-butanol, and various polyhydric alcohols.

  Next, a method for producing an electrolyte membrane-catalyst layer assembly, an electrolyte membrane-electrode assembly, and a polymer electrolyte fuel cell using the catalyst layer transfer sheet 1 will be described with reference to FIG.

  First, an electrolyte membrane 4 having a rectangular shape in plan view is prepared, and the catalyst layer transfer sheet 1 is arranged above and below the electrolyte membrane 4 so that the catalyst layer 3 faces the electrolyte membrane 4 side so as to sandwich the membrane from above and below. To do. (FIG. 3A).

  Next, a heat press is applied from the back side of each catalyst layer transfer sheet 1 to transfer the catalyst layer 3 to the upper and lower surfaces of the electrolyte membrane 4. In consideration of workability, it is preferable to transfer the catalyst layer 3 simultaneously on both sides in the step of transferring the catalyst layer 3 to the electrolyte membrane 4, but the catalyst layer 3 can also be formed on each side. The pressure level of the heating press is usually about 0.5 to 20 MPa, preferably about 1 to 10 MPa in order to avoid transfer failure. In addition, it is preferable to heat the pressure surface during this pressure operation in order to minimize transfer defects. The heating temperature is usually 200 ° C. or lower, preferably 150 ° C. or lower, in order to avoid damage or deformation of the electrolyte membrane 4.

  And the holding part 22 of the base material 2 of each catalyst layer transfer sheet 1 is gripped and lifted upward (FIG. 3B). In addition, it is preferable that angle (theta) which the base-material main body 21 and the holding part 22 make at this time shall be about 0-10 degree | times. Subsequently, the base material body 21 is peeled from the catalyst layer 3 by pulling the lifted gripping portion 22 in the left direction of FIG. 3 (FIG. 3C). In this way, the electrolyte membrane-catalyst layer assembly 10 is produced by peeling off the entire base material 2 (FIG. 3D).

  On each catalyst layer 3 of the electrolyte membrane-catalyst layer assembly 10 manufactured in this way, the gas diffusion layer 5 is laminated by thermocompression bonding to manufacture the electrolyte membrane-electrode assembly 20 (FIG. 3 ( e)). Then, a frame-like gasket 6 is provided so as to surround each electrode E composed of the catalyst layers 3 and the gas diffusion layers 5, and finally the separator 7 and the gas flow path 71 are opposed to the gas diffusion layers 5. In this way, the electrolyte membrane-electrode assembly 20 is sandwiched between the gas diffusion layer 5 and the gasket 6 and sandwiched between the separator 7 so that the gas diffusion layer 5 and the separator 7 are electrically connected. The molecular fuel cell 30 is completed (FIG. 3 (f)).

  In addition, as a material of the said electrolyte membrane 4, it forms by apply | coating the solution containing a hydrogen ion conductive polymer electrolyte on a base material, and drying, for example. Examples of the hydrogen ion conductive polymer electrolyte include a perfluorosulfonic acid-based fluorine ion exchange resin, more specifically, a perfluorocarbonsulfonic acid-based resin in which the C—H bond of a hydrocarbon ion-exchange membrane is substituted with fluorine. Examples include polymers (PFS polymers). By introducing a fluorine atom having high electronegativity, it is chemically very stable, the dissociation degree of the sulfonic acid group is high, and high ion conductivity can be realized. Specific examples of such a hydrogen ion conductive polymer electrolyte include “Nafion” (registered trademark) manufactured by DuPont, “Flemion” (registered trademark) manufactured by Asahi Glass Co., Ltd., and “Aciplex” manufactured by Asahi Kasei Corporation. ”(Registered trademark),“ Gore Select ”(registered trademark) manufactured by Gore, and the like. The concentration of the hydrogen ion conductive polymer electrolyte contained in the hydrogen ion conductive polymer electrolyte-containing solution is usually about 5 to 60% by weight, preferably about 20 to 40% by weight. In addition, the film thickness of the electrolyte membrane 4 is about 20-250 micrometers normally, Preferably it is about 20-80 micrometers.

  Further, the material of the gas diffusion layer 5 is known, and various gas diffusion layers constituting a fuel electrode and an air electrode can be used, and fuel gas and oxidant gas as fuel are efficiently supplied to the catalyst layer 3. Therefore, it consists of a porous conductive substrate. Examples of the porous conductive substrate include carbon paper and carbon cloth.

  As the material of the gasket 6, it is possible to use a material that has a strength sufficient to withstand hot pressing and has a gas barrier property that does not leak fuel and oxidant to the outside. For example, a polyethylene terephthalate sheet or Examples thereof include a Teflon (registered trademark) sheet and a silicon rubber sheet.

  The material of the separator 7 is known and may be any conductive plate that is stable even in the environment inside the fuel cell. In general, a material obtained by forming a gas flow path 71 on a carbon plate is used. In addition, the separator 7 is made of a metal such as stainless steel, and the surface of the metal is formed with a coating made of a conductive material such as chromium, a platinum group metal or oxide thereof, or a conductive polymer. It is also possible to use a metal having a metal surface plated with a material such as silver, a platinum group composite oxide, or chromium nitride.

  As described above, according to the present embodiment, the gripping portion 22 of the base material 2 is grasped and pulled, so that the base material 2 is peeled off and does not come into contact with the catalyst layer 3 when the base material 2 is peeled off. There is no damage to layer 3. For this reason, generation | occurrence | production of the peeling defect that the catalyst layer 3 will peel with the base material 2 can be suppressed, and a yield can be improved. In addition, since the grip portion 22 is folded on the base body 21, the grip portion 22 may damage the electrolyte membrane 4 when the hot pressing is performed, or the grip portion 22 sticks to the electrolyte membrane 4. It is possible to solve the problem such as.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to these, A various change is possible unless it deviates from the meaning of this invention. For example, in the said embodiment, although the base material main body 21 and the holding part 22 which comprise the base material 2 are comprised by connecting a separate member, this base material main body 21 and the holding part 22 are integrated. Can be formed. For example, as shown in FIG. 4, one sheet made of the material constituting the base body 21 described above is prepared, this sheet is bent into two at the center line, and one is the base body 21 and the other is The grip portion 22 can be used.

  Moreover, in the said embodiment, since the holding | grip part 22 is only folded and laminated | stacked on the base-material main body 21, there exists a possibility that the holding | grip part 22 may spread from the folded state. If the part 22 spreads out arbitrarily, it is not preferable from the surface of handling. In order to prevent this, for example, as shown in FIG. 5, an adhesive made of a weak adhesive elastomer material such as silicon rubber, butyl rubber, or fluorine rubber is applied between the base body 21 and the grip portion 22. An adhesive layer 23 can be interposed. The adhesive layer 23 does not need to be formed on the entire surface between the base body 21 and the grip portion 22 and may be formed only on a part thereof. In addition, since it will become difficult to peel the holding | grip part 22 from the base-material main body 21 when the adhesive force by this adhesion layer 23 is too strong, and it is unpreferable from the surface of handling, adhesive force of the grade which the adhesion layer 23 can peel easily, For example, it is preferable to make it adhere with an adhesive strength of about 0.05 to 3.0 N / 20 mm (measured by the measurement method specified in JISZ 0237 (2000)). In addition to interposing the adhesive layer 23, for example, the above-mentioned problem can be solved by configuring the grip portion 22 with a material having weak adhesive properties such as silicone.

  Moreover, in the said embodiment, although the holding part 22 is made into the same shape and the same area as the base material main body 21, it is not limited to this in particular, The holding part 22 can also be formed smaller than the base material main body 21. . In this case, the thickness of the gripping portion 22 is preferably set to 1 to 15 μm or less in order to avoid a local increase in pressure or difficulty in applying heat.

  Moreover, in the said embodiment, although the holding part 22 is connected with the base-material main body 21 in which the catalyst layer 3 was formed, after connecting the holding part 22 to the base-material main body 21 previously, the catalyst layer 3 is formed after that. You can also.

It is a front view which shows embodiment of the catalyst layer transfer sheet which concerns on this invention. It is a top view which shows embodiment of the catalyst layer transfer sheet which concerns on this invention. It is explanatory drawing which shows the manufacturing method of the polymer electrolyte fuel cell which concerns on this invention. It is a front view which shows other embodiment of the base material of the catalyst layer transfer sheet which concerns on this invention. It is a front view which shows other embodiment of the catalyst layer transfer sheet which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Catalyst layer transfer sheet 2 Base material 21 Base material main body 22 Holding part 3 Catalyst layer 4 Electrolyte membrane 5 Gas diffusion layer 6 Gasket 7 Separator 10 Electrolyte membrane-catalyst layer assembly 20 Electrolyte membrane-electrode assembly 30 Solid polymer fuel battery

Claims (7)

A base material having a sheet-like gripping portion that is connected to a part of the outer peripheral edge of the base material body and is folded to be laminated on one surface of the base material body;
A catalyst layer formed on the other surface of the substrate body;
A catalyst layer transfer sheet.   The catalyst layer transfer sheet according to claim 1, wherein the grip portion has the same shape and the same area as the base body, and is formed so as to cover the entire base body. The base body has a rectangular shape in plan view,
The catalyst layer transfer sheet according to claim 1 or 2, wherein the grip portion is connected to the base body at a corner of the base body.   The catalyst layer transfer sheet according to any one of claims 1 to 3, wherein the grip portion is detachably bonded to one surface of the base body in a folded state. Preparing two catalyst layer transfer sheets according to any one of claims 1 to 4,
A step of preparing an electrolyte membrane;
Disposing each catalyst layer transfer sheet with the catalyst layer facing the electrolyte membrane so as to sandwich the electrolyte membrane between the catalyst layer transfer sheets;
Transferring the catalyst layer of the catalyst layer transfer sheet to both surfaces of the electrolyte membrane;
A step of grasping the grip portion and peeling the base material;
A method for producing an electrolyte membrane-catalyst layer assembly comprising: A method for producing the electrolyte membrane-catalyst layer assembly according to claim 5,
Forming a gas diffusion layer on each catalyst layer;
A method for producing an electrolyte membrane-electrode assembly, comprising: A method for producing the electrolyte membrane-electrode assembly according to claim 6,
Installing a gasket so as to surround the periphery of the electrolyte membrane-electrode assembly;
Installing a separator so as to sandwich the electrolyte membrane-electrode assembly;
A method for producing a polymer electrolyte fuel cell comprising:

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