JP2005310545A

JP2005310545A - Method for producing polymer electrolyte fuel cell

Info

Publication number: JP2005310545A
Application number: JP2004125557A
Authority: JP
Inventors: Mikiko Yoshimura; 美貴子吉村; Yoshihiro Hori; 堀　　喜博; Akihiko Yoshida; 昭彦吉田; Makoto Uchida; 誠内田; Masaki Yamauchi; 将樹山内
Original assignee: Matsushita Electric Industrial Co Ltd
Current assignee: Panasonic Holdings Corp
Priority date: 2004-04-21
Filing date: 2004-04-21
Publication date: 2005-11-04

Abstract

【課題】触媒層塗工時の塗工開始時から高分子電解質膜上への触媒層の形成までの過程において、触媒インク中の溶媒の含有量を制御することが可能な高分子電解質型燃料電池の製造方法を提供する。
【解決手段】高分子電解質型燃料電池の製造方法は、水素イオン伝導性高分子電解質を付着させた触媒担持粒子を含む触媒インクを得る工程（１）、触媒インクをノズルから射出するとともに、この触媒インクに触媒インク１ｍｇあたり３〜１００ｃｍ³の気体を衝突させて空中にスプレーする工程（２）、および工程（２）で得られた霧状の触媒インクを基盤上に配された水素イオン伝導性高分子電解質膜上に塗着させて、触媒層を得る工程（３）を含む。
【選択図】なしPROBLEM TO BE SOLVED: To provide a polymer electrolyte fuel capable of controlling the content of a solvent in a catalyst ink in the process from the start of coating at the time of coating a catalyst layer to the formation of a catalyst layer on a polymer electrolyte membrane. A method for manufacturing a battery is provided.
A method for producing a polymer electrolyte fuel cell includes a step (1) of obtaining a catalyst ink including catalyst-carrying particles to which a hydrogen ion conductive polymer electrolyte is attached, and ejecting the catalyst ink from a nozzle. Step (2) in which gas of ³ to 100 cm ³ per 1 mg of catalyst ink is collided with catalyst ink and sprayed into the air, and hydrogen ion conduction in which the atomized catalyst ink obtained in step (2) is arranged on the substrate A step (3) of applying a catalyst polymer layer on the conductive polymer electrolyte membrane.
[Selection figure] None

Description

本発明は、高分子電解質型燃料電池の製造方法に関し、特にその触媒層の作製方法に関する。 The present invention relates to a method for producing a polymer electrolyte fuel cell, and more particularly to a method for producing a catalyst layer thereof.

高分子電解質型燃料電池は、水素を含有する燃料ガスと、空気など酸素を含有する燃料ガスとを、電気化学的に反応させて、電力と熱とを同時に発生させる。
水素イオンを選択的に輸送する高分子電解質膜の両面には、触媒層が形成されている。触媒層には、白金などの金属触媒を担持したカーボン粉末からなる触媒体と水素イオン伝導性高分子電解質とを混合したものが用いられる。そして、触媒層上に、通気性と電子伝導性を有するガス拡散層が形成される。ガス拡散層には、例えば、カーボンペーパーなどのガス拡散層基材上に、ポリテトラフルオロエチレンなどの撥水材および導電性カ−ボンからなる撥水カーボン層が形成されたものが用いられる。このように、水素イオン伝導性高分子電解質膜の両側に、触媒層およびガス拡散層からなる電極を接合したものを膜・電極接合体（ＭＥＡ）と呼ぶ。 In a polymer electrolyte fuel cell, a fuel gas containing hydrogen and a fuel gas containing oxygen such as air are electrochemically reacted to generate electric power and heat simultaneously.
Catalyst layers are formed on both sides of the polymer electrolyte membrane that selectively transports hydrogen ions. For the catalyst layer, a mixture of a catalyst body made of carbon powder carrying a metal catalyst such as platinum and a hydrogen ion conductive polymer electrolyte is used. And the gas diffusion layer which has air permeability and electronic conductivity is formed on a catalyst layer. As the gas diffusion layer, for example, a gas diffusion layer base material such as carbon paper on which a water repellent carbon layer made of a water repellent material such as polytetrafluoroethylene and conductive carbon is formed is used. Thus, what joined the electrode which consists of a catalyst layer and a gas diffusion layer on both sides of a hydrogen ion conductive polymer electrolyte membrane is called a membrane electrode assembly (MEA).

触媒層の作製方法としては、大きく二つに大別される。高分子電解質膜に直接形成する方法と、他基材またはガス拡散層上に形成した後、高分子電解質膜に接合する方法である。前者の作製方法では、高分子電解質膜への機械的ダメージは軽減されるが、依然として水素イオン伝導性を改善する必要がある。一方、後者の作製方法では、熱転写による場合が多く、高分子電解質膜への機械的なダメージが大きいだけでなく、高分子電解質膜と触媒層との間における水素イオン伝導性の低下が懸念される。 There are roughly two methods for producing the catalyst layer. There are a method of directly forming on the polymer electrolyte membrane and a method of forming on the other substrate or gas diffusion layer and then bonding to the polymer electrolyte membrane. In the former manufacturing method, mechanical damage to the polymer electrolyte membrane is reduced, but it is still necessary to improve hydrogen ion conductivity. On the other hand, the latter production method is often due to thermal transfer, and not only the mechanical damage to the polymer electrolyte membrane is large, but also there is a concern about the decrease in hydrogen ion conductivity between the polymer electrolyte membrane and the catalyst layer. The

高分子電解質膜に直接触媒層を塗工する方法としては、スクリーン印刷法、ローラー式、スプレー式、インクジェット式などの方法が挙げられる。スクリーン印刷法やローラー式では、少量のインクを塗布するのが困難であり、逆にインクの塗布量が多くなりすぎると、被塗着物である高分子電解質膜の膨潤が生じる。また、インクジェット式では、インクの塗布量が非常に微量であるため、触媒層のサイズが小さい場合には、塗工時間が長くなる。これに対して、スプレー式では、塗布量を任意に変化させることが可能であり、低粘度なインクに対しても、安定的な塗布量を得ることができる。また、スプレー式では、少量ずつ複数回スプレーすることにより触媒層を形成することができるため、他の方法に比べて、プロトン伝導性とガス拡散性をバランスよく成立させることができると報告されている（例えば、特許文献１）。 Examples of the method for directly applying the catalyst layer to the polymer electrolyte membrane include a screen printing method, a roller method, a spray method, and an ink jet method. In the screen printing method or the roller method, it is difficult to apply a small amount of ink, and conversely, if the amount of ink applied is too large, the polymer electrolyte membrane that is the object to be coated swells. Further, in the ink jet type, since the amount of ink applied is very small, the coating time becomes long when the size of the catalyst layer is small. On the other hand, in the spray type, the coating amount can be arbitrarily changed, and a stable coating amount can be obtained even for low viscosity ink. In addition, since the catalyst layer can be formed by spraying a small amount several times with the spray method, it has been reported that proton conductivity and gas diffusibility can be established in a balanced manner compared to other methods. (For example, Patent Document 1).

しかし、スプレー式では、使用される触媒インクの粘度は低く、触媒インク中の溶媒の割合が大きいため、溶媒の蒸発速度が遅い場合は被塗着物である高分子電解質膜の膨潤が生じる可能性がある。また、逆に溶媒の蒸発速度が速い場合は高分子電解質膜との結着性が悪くなり、触媒層のひび割れ、剥離が生じてしまう。さらに、触媒層の厚さ方向における積層状態が悪くなると、水素イオン伝導性の低下だけでなく、ガス拡散性にも悪影響を及ぼす可能性がある。 However, in the spray type, the viscosity of the catalyst ink used is low and the ratio of the solvent in the catalyst ink is large. Therefore, when the solvent evaporation rate is low, the polymer electrolyte membrane that is the object to be coated may swell. There is. On the other hand, when the evaporation rate of the solvent is high, the binding property with the polymer electrolyte membrane is deteriorated, and the catalyst layer is cracked and peeled off. Furthermore, when the lamination state in the thickness direction of the catalyst layer is deteriorated, there is a possibility that not only the hydrogen ion conductivity is lowered but also gas diffusibility is adversely affected.

燃料電池の実用化に対して、高い電池電圧および優れた寿命特性を両立させることが重要である。しかし、上述のように、触媒層と高分子電解質膜の連続的な結着性の確保および高分子電解質膜の膨潤防止が困難であり、触媒層の剥離、ひび割れ、ピンホールなどが生じやすいという問題があった。また、高分子電解質膜が膨潤しやすく、かつ触媒層の厚さ方向における水素イオンの伝導経路が不連続となりやすいため、さらに、初期の電池電圧の低下および耐久性の低下という問題があった。
特開２００２−２９８８６０号公報 For the practical use of fuel cells, it is important to achieve both high battery voltage and excellent life characteristics. However, as described above, it is difficult to ensure continuous binding between the catalyst layer and the polymer electrolyte membrane and to prevent swelling of the polymer electrolyte membrane, and the catalyst layer is likely to be peeled off, cracked, pinholes, etc. There was a problem. In addition, since the polymer electrolyte membrane easily swells and the hydrogen ion conduction path in the thickness direction of the catalyst layer tends to be discontinuous, there is a problem that the initial battery voltage is lowered and the durability is lowered.
JP 2002-298860 A

そこで、本発明では、上記の諸問題を解決するため、触媒層塗工時の塗工開始時から高分子電解質膜上への触媒層の形成までの過程において、触媒インク中の溶媒の含有量を制御することが可能な高分子電解質型燃料電池の製造方法を提供することを目的とする。 Therefore, in the present invention, in order to solve the above problems, the content of the solvent in the catalyst ink in the process from the start of coating at the time of coating the catalyst layer to the formation of the catalyst layer on the polymer electrolyte membrane. It is an object of the present invention to provide a method for producing a polymer electrolyte fuel cell capable of controlling the above.

本発明の高分子電解質型燃料電池は、水素イオン伝導性高分子電解質膜、ならびに前記電解質膜を挟む触媒層およびガス拡散層からなる電極で構成される膜・電極接合体を含む高分子電解質型燃料電池の製造方法であって、（１）水素イオン伝導性高分子電解質を付着させた触媒担持粒子を含む触媒インクを得る工程、（２）触媒インクをノズルから射出するとともに、前記触媒インクに触媒インク１ｍｇあたり３〜１００ｃｍ³の気体を衝突させて空中にスプレーする工程、および（３）前記工程（２）で得られた霧状の触媒インクを基盤上に配された水素イオン伝導性高分子電解質膜上に塗着させて、触媒層を得る工程を含む。 The polymer electrolyte fuel cell of the present invention is a polymer electrolyte type comprising a membrane / electrode assembly composed of a hydrogen ion conductive polymer electrolyte membrane and an electrode comprising a catalyst layer and a gas diffusion layer sandwiching the electrolyte membrane. A method for producing a fuel cell, comprising: (1) obtaining a catalyst ink containing catalyst-carrying particles to which a hydrogen ion conductive polymer electrolyte is attached; (2) ejecting the catalyst ink from a nozzle; A step of colliding ³ to 100 cm ³ of gas per 1 mg of the catalyst ink and spraying it in the air; and (3) a high hydrogen ion conductivity in which the atomized catalyst ink obtained in the step (2) is arranged on the substrate. The method includes a step of applying on the molecular electrolyte membrane to obtain a catalyst layer.

前記工程（２）において、基盤からノズルの開口部までの高さが５０〜１５０ｍｍであるのが好ましい。
前記基盤の温度が３０〜７０℃であるのが好ましい。
前記工程（１）において触媒インク中の溶媒の割合が８５〜９５重量％であるのが好ましい。
前記触媒層の表面における算術平均粗さ（Ｒａ）が３μｍ以下であるのが好ましい。 In the step (2), the height from the base to the nozzle opening is preferably 50 to 150 mm.
It is preferable that the temperature of the base is 30 to 70 ° C.
In the step (1), the ratio of the solvent in the catalyst ink is preferably 85 to 95% by weight.
The arithmetic average roughness (Ra) on the surface of the catalyst layer is preferably 3 μm or less.

本発明によれば、触媒層の高分子電解質膜との結着性が改善されることにより、触媒層の剥離およびひび割れが解消される。また、安定した塗工により触媒層の表面粗さが改善され、触媒層の表面における算術平均粗さを３μｍ以下とすることができる。触媒層の被覆状態および触媒層の厚さ方向における水素イオン伝導性の改善、ならびに高分子電解質膜の膨潤の防止により、長期にわたり安定した出力特性を有する耐久性に優れた高分子電解質型燃料電池を提供することができる。 According to the present invention, separation of the catalyst layer and cracking are eliminated by improving the binding property of the catalyst layer to the polymer electrolyte membrane. Moreover, the surface roughness of the catalyst layer is improved by the stable coating, and the arithmetic average roughness on the surface of the catalyst layer can be 3 μm or less. Polymer electrolyte fuel cell with excellent durability and stable output characteristics over a long period of time by improving the hydrogen ion conductivity in the coating state and thickness direction of the catalyst layer and preventing the swelling of the polymer electrolyte membrane Can be provided.

さらに、高分子電解質膜を載置する基盤からノズル開口部までの高さ、基盤の温度、および触媒インク中の溶媒の割合を制御することにより、触媒層と高分子電解質膜との結着性を改善し、高分子電解質膜の膨潤を防止するだけでなく、触媒層の厚さ方向の水素イオン伝導性を確保することができる。 Furthermore, by controlling the height from the substrate on which the polymer electrolyte membrane is placed to the nozzle opening, the temperature of the substrate, and the ratio of the solvent in the catalyst ink, the binding property between the catalyst layer and the polymer electrolyte membrane In addition to preventing swelling of the polymer electrolyte membrane, hydrogen ion conductivity in the thickness direction of the catalyst layer can be ensured.

本発明は、スプレーによる触媒層の塗工時の、触媒インクのスプレー直後から高分子電解質膜上に触媒層を形成するまでの過程において、触媒インク中の溶媒の含有量を制御することが可能な高分子電解質型燃料電池の製造方法に関する。
すなわち、本発明の高分子電解質型燃料電池の製造方法は、（１）水素イオン伝導性高分子電解質を付着させた触媒担持粒子を含む触媒インクを得る工程、（２）触媒インクをノズルから射出するとともに、前記触媒インクに触媒インク１ｍｇあたり３〜１００ｃｍ³の気体を衝突させて空中にスプレーする工程、および（３）前記工程（２）で得られた霧状の触媒インクを基盤上に配された水素イオン伝導性高分子電解質膜上に塗着させて、触媒層を得る工程を含む。 The present invention can control the content of the solvent in the catalyst ink in the process from spraying of the catalyst ink to the formation of the catalyst layer on the polymer electrolyte membrane when the catalyst layer is applied by spraying. The present invention relates to a method for manufacturing a novel polymer electrolyte fuel cell.
That is, the method for producing a polymer electrolyte fuel cell of the present invention includes (1) a step of obtaining a catalyst ink containing catalyst-carrying particles to which a hydrogen ion conductive polymer electrolyte is attached, and (2) injection of the catalyst ink from a nozzle. And a step of colliding 3-100 cm ³ of gas per 1 mg of the catalyst ink with the catalyst ink and spraying it in the air, and (3) arranging the atomized catalyst ink obtained in the step (2) on the substrate. And a step of coating the formed hydrogen ion conductive polymer electrolyte membrane to obtain a catalyst layer.

工程（１）の触媒インクを得る方法としては、触媒担持粒子に高分子電解質を付着させた後に溶媒中に分散させても、触媒担持粒子を高分子電解質溶液中に分散させてもよい。
工程（２）でノズルから空中にスプレーされた触媒インク中の触媒担持粒子は、その周囲に付着した電解質溶液の表面張力により電解質溶液で均一に覆われた状態となる。このとき、空中での触媒インク中に含まれる溶媒の蒸発量を制御することが重要となる。 As a method for obtaining the catalyst ink in the step (1), the polymer electrolyte may be attached to the catalyst-carrying particles and then dispersed in a solvent, or the catalyst-carrying particles may be dispersed in the polymer electrolyte solution.
The catalyst-carrying particles in the catalyst ink sprayed into the air from the nozzle in the step (2) are uniformly covered with the electrolyte solution due to the surface tension of the electrolyte solution adhering to the periphery. At this time, it is important to control the evaporation amount of the solvent contained in the catalyst ink in the air.

本発明では、この蒸発量を制御し易くするために、ノズルより触媒インクを射出するとともに、この触媒インクに気体を衝突させて、霧化させた触媒インクを空中にスプレーする。この気体には、窒素ガス、空気等の不活性ガスが用いられる。空中にスプレーされた触媒インクは、細かい霧状または粒状である。触媒インク中の溶媒の蒸発量は、触媒インクに衝突させる気体の量により変化する。この気体の量が触媒インク１ｍｇあたり３〜１００ｃｍ³のときに、後述する高分子電解質膜との触媒層の結着性が良好となる。 In the present invention, in order to easily control the evaporation amount, the catalyst ink is ejected from the nozzle, and a gas is collided with the catalyst ink to spray the atomized catalyst ink into the air. An inert gas such as nitrogen gas or air is used as this gas. The catalyst ink sprayed in the air is fine mist or granular. The amount of evaporation of the solvent in the catalyst ink varies depending on the amount of gas that collides with the catalyst ink. When the amount of the gas is ³ to 100 cm ³ per 1 mg of the catalyst ink, the binding property of the catalyst layer with the polymer electrolyte membrane described later is good.

気体の量が３ｃｍ³未満の場合は、空中にスプレーされてから高分子電解質膜上に塗着されるまでの間に蒸発する触媒インク中の溶媒量が少ないため、高分子電解質膜が膨潤しやすくなり、耐久性の低下を引き起こす。一方、気体の量が１００ｃｍ³を超えると、触媒インク中の溶媒の蒸発量が多くなるため、高分子電解質膜と触媒層の結着性が低下し、水素イオン伝導性が低下すると同時に、触媒層のひび割れや剥離を引き起こす。 When the amount of gas is less than 3 cm ³ , the polymer electrolyte membrane swells because the amount of solvent in the catalyst ink that evaporates between spraying in the air and coating on the polymer electrolyte membrane is small. It becomes easy to cause a decrease in durability. On the other hand, if the amount of gas exceeds 100 cm ³ , the amount of evaporation of the solvent in the catalyst ink increases, so that the binding property between the polymer electrolyte membrane and the catalyst layer is lowered, and the hydrogen ion conductivity is lowered. Causes cracking and delamination of the layer.

工程（２）において、基盤からノズルの開口部までの高さは、触媒インクの空中での滞在時間を変えるため、触媒インク中に含まれる溶媒の蒸発量を制御する因子となる。
この基盤からノズルの開口部までの高さが５０〜１５０ｍｍであるのが好ましい。この高さが５０ｍｍ未満では、溶媒の蒸発量が少なく、またスプレーによる触媒インクの広がりが小さいため、触媒層の塗りむらが生じやすい。一方、この高さが１５０ｍｍを超えると、溶媒の蒸発量が多くなり、また、触媒インクの広がりも大きくなるため、触媒インクの歩止まりが低下する。 In step (2), the height from the base to the opening of the nozzle changes the residence time of the catalyst ink in the air, and thus becomes a factor for controlling the evaporation amount of the solvent contained in the catalyst ink.
The height from the base to the nozzle opening is preferably 50 to 150 mm. If this height is less than 50 mm, the amount of evaporation of the solvent is small and the spread of the catalyst ink by spraying is small, so that uneven coating of the catalyst layer tends to occur. On the other hand, if the height exceeds 150 mm, the amount of solvent evaporation increases and the spread of the catalyst ink also increases, so the yield of the catalyst ink decreases.

霧化された触媒インクを高分子電解質膜上に塗着させる工程（３）では、触媒担持粒子は、その周囲が電解質で均一に覆われた状態で高分子電解質膜上に積層し、触媒層が形成される。このとき、触媒層には孔が均一に形成される。高分子電解質膜は、例えば、真空ポンプが接続された多孔質材料からなるテーブルに密着固定される。このテーブルは、室温以上の温度制御が可能であり、スプレー塗工された触媒インクを任意の時間で乾燥させることができる。この基盤の温度を変えることにより、高分子電解質膜上に塗着した触媒インク中の溶媒の蒸発量を制御することができる。さらには、半乾燥状態で触媒層を積層することができ、触媒層の厚さ方向に連続した水素イオン伝導経路を形成することができる。 In the step (3) of applying the atomized catalyst ink on the polymer electrolyte membrane, the catalyst-carrying particles are laminated on the polymer electrolyte membrane in a state where the periphery thereof is uniformly covered with the electrolyte, and the catalyst layer Is formed. At this time, pores are uniformly formed in the catalyst layer. For example, the polymer electrolyte membrane is tightly fixed to a table made of a porous material to which a vacuum pump is connected. This table can control the temperature above room temperature, and can dry the spray-coated catalyst ink in an arbitrary time. By changing the temperature of this substrate, the evaporation amount of the solvent in the catalyst ink coated on the polymer electrolyte membrane can be controlled. Furthermore, a catalyst layer can be laminated | stacked in a semi-dry state, and the hydrogen ion conduction path | route continuous in the thickness direction of the catalyst layer can be formed.

基盤の温度は３０〜７０℃であるのが好ましい。基盤上に高分子電解質膜が配されているため、基盤の温度が高分子電解質膜の温度に影響を与える。基盤の温度が３０℃未満の場合では、触媒インクの塗着後における溶媒の蒸発量が少ないため、高分子電解質膜が膨潤しやすい。一方、基盤の温度が７０℃を超えると、蒸発量が多くなり、触媒層の剥離を引き起こす。この基盤の温度は、高分子電解質膜と触媒層の結着性だけでなく、触媒層の厚さ方向における水素イオンの伝導経路の連続性にも影響を与える。 The temperature of the substrate is preferably 30 to 70 ° C. Since the polymer electrolyte membrane is arranged on the substrate, the temperature of the substrate affects the temperature of the polymer electrolyte membrane. When the temperature of the substrate is lower than 30 ° C., the polymer electrolyte membrane tends to swell because the amount of evaporation of the solvent after applying the catalyst ink is small. On the other hand, when the temperature of the substrate exceeds 70 ° C., the amount of evaporation increases, causing peeling of the catalyst layer. The temperature of this base affects not only the binding property between the polymer electrolyte membrane and the catalyst layer, but also the continuity of the conduction path of hydrogen ions in the thickness direction of the catalyst layer.

工程（１）における触媒インク中の溶媒の割合が、８５〜９５重量％であるのが好ましい。溶媒の割合が８５重量％未満の場合、すなわち触媒インクの固形成分が１５重量％を超える場合は、触媒インクの粘度が大きくなるため、スプレーノズルが詰まりやすくなり、安定的な塗工が困難になる。一方、溶媒の割合が９５重量％を超える場合は、触媒インクの粘度が低くなるため、塗工量のばらつきが大きくなり、さらに、高分子電解質膜が膨潤しやすくなる。 The ratio of the solvent in the catalyst ink in the step (1) is preferably 85 to 95% by weight. When the ratio of the solvent is less than 85% by weight, that is, when the solid component of the catalyst ink exceeds 15% by weight, the viscosity of the catalyst ink increases, so that the spray nozzle is likely to be clogged and stable coating becomes difficult. Become. On the other hand, when the ratio of the solvent exceeds 95% by weight, the viscosity of the catalyst ink becomes low, so that the variation in the coating amount increases, and the polymer electrolyte membrane easily swells.

上記の作製方法で得られる触媒層の表面の凹凸を示す算術平均粗さ（Ｒａ）は３μｍ以下であるのが好ましい。算術平均粗さ（Ｒａ）が３μｍを超えると、触媒層表面の平坦性が欠如し、触媒層のガス拡散層との密着性が低下する。表面の凹凸は触媒インク中の溶媒量に大きく影響し、高分子電解質膜と触媒層の結着性の改善の指標にもなりうる。この触媒層表面の平坦性の欠如は、フラッディング現象による電池電圧の低下および耐久性の低下をもたらす。 The arithmetic average roughness (Ra) indicating the unevenness of the surface of the catalyst layer obtained by the above production method is preferably 3 μm or less. When the arithmetic average roughness (Ra) exceeds 3 μm, the flatness of the catalyst layer surface is lacking, and the adhesion of the catalyst layer to the gas diffusion layer decreases. The unevenness of the surface greatly affects the amount of solvent in the catalyst ink, and can be an index for improving the binding property between the polymer electrolyte membrane and the catalyst layer. This lack of flatness on the surface of the catalyst layer results in a decrease in battery voltage and a decrease in durability due to a flooding phenomenon.

以下、本発明の実施例を詳しく説明する。
《実施例１》
（１）触媒層の作製
導電性カーボン粒子として平均一次粒子径が３０ｎｍのケッチェンブラックＥＣ（オランダ国、ＡＫＺＯＣｈｅｍｉｅ社）に、平均粒径約３０Åの白金粒子を重量比５０：５０の割合で担持させて、カソード側の触媒担持粒子を得た。この触媒担持粒子に、まず水を加え、次に水素イオン伝導性高分子電解質のエタノ−ル分散液（旭硝子（株）製、フレミオン）を加えた後、混合・攪拌し、触媒担持粒子上に高分子電解質を被覆した。なお、高分子電解質にはパーフルオロカーボンスルホン酸を用いた。 Examples of the present invention will be described in detail below.
Example 1
(1) Preparation of catalyst layer As conductive carbon particles, platinum particles having an average particle diameter of about 30 mm are mixed with Ketjen Black EC (Netherlands, AKZO Chemie) having an average primary particle diameter of 30 nm at a weight ratio of 50:50. The catalyst-supported particles on the cathode side were obtained. First, water is added to the catalyst-supported particles, and then an ethanol dispersion of hydrogen ion conductive polymer electrolyte (Flemion, manufactured by Asahi Glass Co., Ltd.) is added, followed by mixing and stirring. Polyelectrolyte was coated. In addition, perfluorocarbon sulfonic acid was used for the polymer electrolyte.

なお、この水は、触媒により水素イオン伝導性高分子電解質の溶媒が燃焼するのを防止するために加えた。この水の添加量については、触媒担持粒子全体が湿潤すればよく、特に限定する必要はないが、本実施例では、触媒担持粒子の重量に対して、３倍の水を加えた。
最後に、高分子電解質で覆われた触媒担持粒子にエタノールを加え、触媒インクを得た。このとき、触媒インク中の高分子電解質の量は、触媒担持粒子の重量に対して８０重量％となるように調整した。また、触媒インク中の溶媒の割合が９０重量％となるように調整した。 This water was added to prevent the catalyst of the hydrogen ion conductive polymer electrolyte from burning by the catalyst. The amount of water to be added is not particularly limited as long as the entire catalyst-carrying particles are wetted. In this example, three times as much water as the weight of the catalyst-carrying particles was added.
Finally, ethanol was added to the catalyst-carrying particles covered with the polymer electrolyte to obtain a catalyst ink. At this time, the amount of the polymer electrolyte in the catalyst ink was adjusted to 80% by weight with respect to the weight of the catalyst-carrying particles. Moreover, it adjusted so that the ratio of the solvent in a catalyst ink might be 90 weight%.

一方、ケッチェンブラックＥＣに平均粒径約３０Åの白金粒子とルテニウム粒子を重量比５０：２５：２５の割合で担持させて、アノード側触媒担持粒子を得た。そして、上述したカソード側触媒インクの場合と同様の方法により、アノード側触媒担持粒子を含む触媒インクを得た。
上記で得られたアノード側触媒インクおよびカソード側触媒インクを、基盤上に密着固定された高分子電解質膜上に直接スプレー塗工し、高分子電解質膜の一方の面にアノード側触媒層、他方の面にカソード側触媒層を形成した。なお、基盤には、真空ポンプが接続されたアルミニウムからなるテーブルが用いられた。なお、テーブルは多孔質であり、テーブルの温度制御は、別容器内でヒータ等の温調機器により所定の温度に制御された水をテーブル内で循環させることにより行った。 On the other hand, platinum particles and ruthenium particles having an average particle size of about 30 mm were supported on Ketjen Black EC at a weight ratio of 50:25:25 to obtain anode-side catalyst-supported particles. A catalyst ink containing anode-side catalyst-supporting particles was obtained by the same method as that for the cathode-side catalyst ink described above.
The anode-side catalyst ink and the cathode-side catalyst ink obtained above are spray-coated directly on the polymer electrolyte membrane tightly fixed on the substrate, and the anode-side catalyst layer and the other are coated on one surface of the polymer electrolyte membrane. A cathode side catalyst layer was formed on the surface. Note that an aluminum table to which a vacuum pump was connected was used as the base. The table was porous, and the temperature of the table was controlled by circulating water controlled to a predetermined temperature by a temperature control device such as a heater in a separate container.

このとき、ノズルより触媒インクを射出するとともに、この触媒インクに窒素ガスを衝突させて、触媒インクを細かい霧状または粒状とした。この霧化させた触媒インクを空中にスプレーし、高分子電解質膜上に塗着させた。このとき、触媒インク１ｍｇあたりに衝突させる窒素ガスの量を５０ｃｍ³とした。なお、窒素ガスの量は圧力により調整した。また、基盤からノズルの開口部までの高さを１００ｍｍ、基盤の温度を５０℃とした。 At this time, the catalyst ink was ejected from the nozzle, and nitrogen gas was collided with the catalyst ink to make the catalyst ink fine mist or granular. The atomized catalyst ink was sprayed in the air and applied onto the polymer electrolyte membrane. At this time, the amount of nitrogen gas collided per 1 mg of the catalyst ink was set to 50 cm ³ . The amount of nitrogen gas was adjusted by pressure. The height from the base to the nozzle opening was 100 mm, and the base temperature was 50 ° C.

（２）ガス拡散層の作製
電極のガス拡散層となるカーボン不織布に対して撥水処理を施した。外寸１６ｃｍ×２０ｃｍ、および厚さ２７０μｍのカーボン不織布（東レ（株）製、ＴＧＰ−Ｈ−９０）を、フッ素樹脂を含有する水性ディスパージョン（ダイキン工業（株）製、ネオフロンＮＤ１）に含浸した後、これを乾燥し、３５０℃で３０分加熱して、カーボン不織布に撥水性を付与した。
さらに、導電性カーボン粉末とＰＴＦＥ（ポリテトラフルオロエチレン）微粉末を含む分散液とを混合して撥水インクを得た。このカーボン不織布の一方の面に、スクリーン印刷法によりこの撥水インクを塗布して撥水カーボン層を形成し、ガス拡散層を得た。このとき、撥水カーボン層の一部は、カーボン不織布の中に埋め込まれた。 (2) Production of gas diffusion layer Water repellent treatment was applied to the carbon non-woven fabric to be the gas diffusion layer of the electrode. A carbon non-woven fabric (TGP-H-90, manufactured by Toray Industries, Inc.) having an outer size of 16 cm × 20 cm and a thickness of 270 μm was impregnated into an aqueous dispersion containing a fluororesin (manufactured by Daikin Industries, Ltd., Neoflon ND1). Thereafter, this was dried and heated at 350 ° C. for 30 minutes to impart water repellency to the carbon nonwoven fabric.
Furthermore, the water-repellent ink was obtained by mixing the conductive carbon powder and the dispersion containing PTFE (polytetrafluoroethylene) fine powder. The water repellent ink was applied to one surface of the carbon nonwoven fabric by a screen printing method to form a water repellent carbon layer to obtain a gas diffusion layer. At this time, a part of the water repellent carbon layer was embedded in the carbon nonwoven fabric.

（３）ＭＥＡの作製
カーボン不織布を撥水層の塗布した面が触媒層の側に接するようにガス拡散層を触媒層にホットプレスで接合して、膜・電極接合体（ＭＥＡ）を得た。ホットプレスの条件は、温度１２０℃、圧力０．５ＭＰａ、およびプレス時間２分とした。さらに、ＭＥＡの水素イオン伝導性高分子電解質膜の外周部にゴム製のガスケットを接合し、ガスケットに冷却水、燃料ガスおよび酸化剤ガス用のマニホールド穴をそれぞれ形成した。 (3) Production of MEA The gas diffusion layer was joined to the catalyst layer by hot pressing so that the surface of the carbon non-woven fabric coated with the water repellent layer was in contact with the catalyst layer side to obtain a membrane / electrode assembly (MEA). . The hot pressing conditions were a temperature of 120 ° C., a pressure of 0.5 MPa, and a pressing time of 2 minutes. Furthermore, a rubber gasket was joined to the outer periphery of the MEA hydrogen ion conductive polymer electrolyte membrane, and manifold holes for cooling water, fuel gas, and oxidant gas were formed in the gasket.

（４）単電池の組み立て
つぎに、セパレータ２枚を用い、ＭＥＡの一方の面に酸化剤ガス流路が形成されたセパレータを、他方の面に燃料ガス流路が形成されたセパレータを重ね合わせ、単電池（以下、電池Ａと表す）を作製した。なお、セパレータには、外寸が２０ｃｍ×３２ｃｍ、厚さが２．０ｍｍの樹脂含浸黒鉛板を用いた。ガス流路の深さは１．０ｍｍとした。このとき、単電池Ａの両端部に、ステンレス製の集電板と電気絶縁材料の絶縁板を配し、さらに端板と締結ロッドでこれらを固定した。このときの締結圧はセパレータの面積あたり１０ｋｇ／ｃｍ²とした。 (4) Cell assembly Next, using two separators, a separator with an oxidant gas channel formed on one side of the MEA and a separator with a fuel gas channel formed on the other side A single battery (hereinafter referred to as battery A) was produced. For the separator, a resin-impregnated graphite plate having an outer size of 20 cm × 32 cm and a thickness of 2.0 mm was used. The depth of the gas channel was 1.0 mm. At this time, a current collector plate made of stainless steel and an insulating plate made of an electrically insulating material were arranged at both ends of the unit cell A, and these were further fixed by an end plate and a fastening rod. The fastening pressure at this time was 10 kg / cm ² per area of the separator.

《比較例１および２》
触媒インク１ｍｇあたりに衝突させる窒素ガスの量を５００ｃｍ³および１ｃｍ³とした以外は、実施例１と同様の方法により電池ＢおよびＣを作製した。 << Comparative Examples 1 and 2 >>
Batteries B and C were produced in the same manner as in Example 1 except that the amount of nitrogen gas collided per 1 mg of the catalyst ink was 500 cm ³ and 1 cm ³ .

［電池の評価］
次の条件で、電池Ａ〜Ｃの出力特性を評価した。電池を７０℃に保持し、アノードおよびカソードにはそれぞれ露点が６４℃および７０℃となるように加温・加湿した水素ガスおよび空気を供給し、燃料ガス利用率は７０％、酸化ガス利用率は４０％に設定した。まず、電池ＡとＢについて電流−電圧特性を調べた。その結果を図１に示す。 [Battery evaluation]
The output characteristics of the batteries A to C were evaluated under the following conditions. The battery is maintained at 70 ° C., and hydrogen gas and air heated and humidified so that the dew points are 64 ° C. and 70 ° C. are supplied to the anode and cathode, respectively, the fuel gas utilization rate is 70%, and the oxidizing gas utilization rate Was set to 40%. First, the current-voltage characteristics of the batteries A and B were examined. The result is shown in FIG.

電池Ａに比べて、電池Ｂの電池電圧が測定したいずれの電流密度でも大きく低下した。比較例１の触媒層は塗工直後から表面が粗く、触媒層の一部が剥離していた。これより、比較例１では、触媒インク中の溶媒の蒸発量が多いため、触媒層と高分子電解質膜との結着性が悪くなったと考えられる。さらに、触媒層の厚さ方向における水素イオン伝導性も悪くなっていると推測される。したがって、電池電圧の低下は、触媒層の剥離による触媒金属量の減少、ならびに結着性の悪化に伴う水素イオン伝導性の低下によるものと考えられる。 Compared to battery A, the battery voltage of battery B was greatly reduced at any measured current density. The catalyst layer of Comparative Example 1 had a rough surface immediately after coating, and a part of the catalyst layer was peeled off. Thus, in Comparative Example 1, it is considered that the binding property between the catalyst layer and the polymer electrolyte membrane was deteriorated because the amount of evaporation of the solvent in the catalyst ink was large. Furthermore, it is estimated that the hydrogen ion conductivity in the thickness direction of the catalyst layer is also deteriorated. Therefore, the decrease in the battery voltage is considered to be due to a decrease in the amount of the catalyst metal due to the separation of the catalyst layer and a decrease in hydrogen ion conductivity accompanying the deterioration of the binding property.

次に、耐久試験として、電池ＡおよびＣを電流密度２００ｍＡ／ｃｍ²で１０００時間放電した。また、この放電中のアノードおよびカソードにおけるドレイン水中に含まれるフッ素イオンの量も調べた。その結果を図２に示す。図２は電池ＡおよびＣの電池電圧およびフッ素イオン排出量の経時変化を示す図である。このフッ素イオンは、高分子電解質膜および触媒層中の高分子電解質に由来する。つまり、耐久試験時の経時的なフッ素イオン量の増加は、触媒層の劣化の進行を意味する。
電池Ｃの電池電圧は時間とともに大きく低下し、それに伴いフッ素イオン量も増加した。電池Ｃでは触媒インク中の溶媒の蒸発量が少ないため、高分子電解質膜の膨潤により触媒層が劣化し、電池の耐久性が低下したと考えられる。 Next, as a durability test, the batteries A and C were discharged at a current density of 200 mA / cm ² for 1000 hours. The amount of fluorine ions contained in the drain water at the anode and cathode during the discharge was also examined. The result is shown in FIG. FIG. 2 is a graph showing changes with time in battery voltages and fluorine ion discharge amounts of batteries A and C. FIG. This fluorine ion is derived from the polymer electrolyte in the polymer electrolyte membrane and the catalyst layer. That is, the increase in the amount of fluorine ions with time during the durability test means the deterioration of the catalyst layer.
The battery voltage of battery C greatly decreased with time, and the amount of fluorine ions increased accordingly. In Battery C, since the amount of solvent evaporation in the catalyst ink is small, it is considered that the catalyst layer deteriorates due to swelling of the polymer electrolyte membrane, and the durability of the battery decreases.

《実施例２》
触媒インク１ｍｇあたりに衝突させる窒素ガスの量を表１に示すように種々に変化させた以外は、実施例１と同様の方法によりＭＥＡを得た。そして、カソード触媒層の表面粗さを評価するため、カソード触媒層の表面を表面粗さ計（（株）ミツトヨ製、サーフテストＳＶ−９６３４）により測定し、算術平均粗さ(Ｒａ)を算出した。その結果を表１に示す。 Example 2
MEA was obtained in the same manner as in Example 1 except that the amount of nitrogen gas collided per 1 mg of the catalyst ink was variously changed as shown in Table 1. In order to evaluate the surface roughness of the cathode catalyst layer, the surface of the cathode catalyst layer is measured with a surface roughness meter (manufactured by Mitutoyo Corporation, Surf Test SV-9634), and the arithmetic average roughness (Ra) is calculated. did. The results are shown in Table 1.

触媒層インク１ｍｇあたりに衝突させる窒素ガスの量が３〜１００ｃｍ³のとき、良好な平滑性が得られた。 Good smoothness was obtained when the amount of nitrogen gas collided per 1 mg of the catalyst layer ink was ³ to 100 cm ³ .

《実施例３》
基盤からノズルの開口部までの高さを５０、１５０および２５０ｍｍと変化させた以外は、実施例１と同様の方法により電池Ｄ〜Ｆを作製し、電流−電圧特性を調べた。その結果を図３に示す。
基盤からノズルの開口部までの高さが２５０ｍｍである電池Ｆの電池電圧は、電池ＤおよびＥと比べて低下した。これは、霧状の触媒インクの空中における滞在時間が長くなり、触媒インク中の溶媒の蒸発量が多くなることにより、触媒層の高分子電解質膜との結着性が低下したためと考えられる。また、２５０ｍｍと高い位置からスプレーするため、目的の部位以外に塗着する触媒層インクの量が増大し、触媒インクの歩留まりが悪くなった。 Example 3
Batteries D to F were produced in the same manner as in Example 1 except that the height from the base to the nozzle opening was changed to 50, 150, and 250 mm, and current-voltage characteristics were examined. The result is shown in FIG.
The battery voltage of the battery F having a height from the base to the nozzle opening of 250 mm was lower than those of the batteries D and E. This is thought to be because the binding time of the catalyst layer to the polymer electrolyte membrane was lowered due to an increase in the residence time of the atomized catalyst ink in the air and an increase in the amount of evaporation of the solvent in the catalyst ink. Further, since the spray was performed from a position as high as 250 mm, the amount of the catalyst layer ink to be applied to the portion other than the target portion increased, and the yield of the catalyst ink was deteriorated.

《実施例４》
基盤からノズルの開口部までの高さを２５、５０、１５０、および２５０ｍｍと変化させ、触媒インク１ｍｇに衝突させる窒素ガスの量を１、５、１００、および５００と変化させた以外は、実施例１と同様の方法により電池を作製し、耐久試験を行いフッ素イオン量を調べた。その結果を表２に示す。 Example 4
Implemented except that the height from the base to the nozzle opening was changed to 25, 50, 150, and 250 mm, and the amount of nitrogen gas that collided with 1 mg of the catalyst ink was changed to 1, 5, 100, and 500 A battery was produced in the same manner as in Example 1, and an endurance test was conducted to examine the amount of fluorine ions. The results are shown in Table 2.

基盤からノズルの開口部までの高さが２５ｍｍの場合では、ドレイン中のフッ素イオン量が多くなり、耐久性が低下した。これは、触媒インクの空中での滞在時間が短いため、触媒インク中の溶媒の蒸発量が少なくなり、高分子電解質膜が膨潤したためと考えられる。さらに、霧状の触媒インクでは平面的な広がりが小さく、塗工方向に沿って、触媒層のむらが観察された。このことは表面粗さからも確認され、実施例１と同様の方法により表面粗さを評価したところ、触媒層の算術平均粗さ（Ｒａ）は３．６ｍｍと大きくなった。また、基盤からノズルの開口部までの高さが２５０ｍｍの場合でも、触媒インク中の溶媒の蒸発量が多くなり、耐久性の低下が観察された。以上より、基盤からノズルの開口部までの高さは５０〜１５０ｍｍであるのが望ましいことがわかった。 When the height from the base to the opening of the nozzle was 25 mm, the amount of fluorine ions in the drain increased and the durability decreased. This is presumably because the residence time of the catalyst ink in the air is short, the amount of solvent evaporation in the catalyst ink is reduced, and the polymer electrolyte membrane is swollen. Further, the planar spread of the atomized catalyst ink was small, and unevenness of the catalyst layer was observed along the coating direction. This was also confirmed from the surface roughness. When the surface roughness was evaluated by the same method as in Example 1, the arithmetic average roughness (Ra) of the catalyst layer was as large as 3.6 mm. Further, even when the height from the base to the nozzle opening was 250 mm, the amount of evaporation of the solvent in the catalyst ink increased, and a decrease in durability was observed. From the above, it was found that the height from the base to the opening of the nozzle is preferably 50 to 150 mm.

《実施例５》
基盤の温度を６０および８０℃と変化させた以外は実施例１と同様の方法により電池Ｇ〜Ｈを作製し、電流−電圧特性を調べた。その結果を図４に示す。
電池Ｇと比べて電池Ｈの電池電圧が低下した。高分子電解質膜に塗着した触媒インクは、高分子電解質膜が８０℃と高温であるため、触媒インク中の溶媒の蒸発量が多くなり、触媒層の高分子電解質膜との結着性が低下した。また、触媒層の厚さ方向における水素イオン伝導経路の連続性が阻害されたと考えられる。 Example 5
Batteries G to H were produced in the same manner as in Example 1 except that the temperature of the substrate was changed to 60 and 80 ° C., and the current-voltage characteristics were examined. The result is shown in FIG.
Compared with the battery G, the battery voltage of the battery H decreased. The catalyst ink applied to the polymer electrolyte membrane has a high polymer electrolyte membrane temperature of 80 ° C., so the amount of solvent evaporation in the catalyst ink increases and the catalyst layer has a binding property with the polymer electrolyte membrane. Declined. Moreover, it is thought that the continuity of the hydrogen ion conduction path in the thickness direction of the catalyst layer was hindered.

《実施例６》
基盤の温度を２０、３０、４０、６０、７０および８０℃と変化させ、触媒インク１ｍｇあたりに衝突させる窒素ガスの量を１、５、１００、および５００と変化させた以外は、実施例１と同様の方法により、電池を作製し、耐久試験を行いフッ素イオン量を調べた。その結果を表３に示す。 Example 6
Example 1 except that the temperature of the substrate was changed to 20, 30, 40, 60, 70, and 80 ° C., and the amount of nitrogen gas that collided per 1 mg of catalyst ink was changed to 1, 5, 100, and 500. A battery was prepared by the same method as above, and an endurance test was conducted to examine the amount of fluorine ions. The results are shown in Table 3.

基盤の温度が２０℃と低い場合はフッ素イオンの排出量が多くなり、耐久性が低下した。これは、塗工時における触媒インク中の溶媒の蒸発量が少なく、高分子電解質膜の膨潤が生じたためと考えられる。また、基盤の温度が８０℃の場合では、触媒インクの蒸発量が多くなり、耐久性が低下した。以上より、基盤の温度は３０〜７０℃が望ましいことがわかった。 When the temperature of the substrate was as low as 20 ° C., the amount of fluorine ions discharged increased and the durability decreased. This is presumably because the amount of evaporation of the solvent in the catalyst ink during coating was small and the polymer electrolyte membrane swelled. Further, when the substrate temperature was 80 ° C., the amount of evaporation of the catalyst ink was increased, and the durability was lowered. From the above, it was found that the substrate temperature is preferably 30 to 70 ° C.

《実施例７》
高分子電解質膜を付着させた触媒担持粒子に加えるエタノールの量を調整して、触媒インク中の溶媒の割合を８０、８５、９０、９５および９８重量％と変化させた以外は実施例１と同様の方法によりカソード側の触媒インクを作製し、触媒インクの粘度を測定した。粘度の測定には、コーン・プレート型回転粘度計（ハーケ社製、ＲＳ１５０）を使用し、コーン・プレート温度を２５℃とした。なお、これらの粘度は剪断速度が１ｓ^-1の時の値を示す。その測定結果を表４に示す。 Example 7
Example 1 except that the amount of ethanol added to the catalyst-carrying particles to which the polymer electrolyte membrane was adhered was adjusted to change the ratio of the solvent in the catalyst ink to 80, 85, 90, 95 and 98% by weight. Cathode side catalyst ink was prepared in the same manner, and the viscosity of the catalyst ink was measured. For the measurement of the viscosity, a cone plate type rotational viscometer (manufactured by Harke, RS150) was used, and the cone plate temperature was set to 25 ° C. These viscosities indicate values when the shear rate is 1 s ⁻¹ . The measurement results are shown in Table 4.

また、これらの触媒インクを用いて実施例１と同様の方法によりそれぞれ高分子電解質膜上にカソード触媒層を形成した。そして、触媒インクを複数回塗工し、触媒層を積層した。このとき、１回あたりのスプレー塗工で、カソード触媒層中の白金量が０．６ｍｇ／ｃｍ²となるような条件で行った。その後、それぞれ同じスプレー条件で塗工を続けた場合の塗工量の推移を表す。なお、このときの塗工量は白金量に換算した。その結果を図５に示す。 In addition, a cathode catalyst layer was formed on the polymer electrolyte membrane in the same manner as in Example 1 using these catalyst inks. And the catalyst ink was applied several times and the catalyst layer was laminated | stacked. At this time, it was performed under such conditions that the amount of platinum in the cathode catalyst layer was 0.6 mg / cm ² by spray coating per one time. Then, the transition of the coating amount when the coating is continued under the same spray conditions is shown. In addition, the coating amount at this time was converted into the amount of platinum. The result is shown in FIG.

図５は、触媒層の塗工回数と、触媒層中に含まれる白金塗布量との関係を示す図である。触媒インク中の溶媒の割合が８５重量％、９０重量％および９５重量％の場合は、触媒層中に含まれる白金量がほぼ一定であった。すなわち、スプレーされた触媒インクの量はほぼ一定であり、安定した塗工が可能であることがわかった。
それに対して、触媒インク中の溶媒の割合が８０重量％の場合では、塗工量が減少した。このように溶媒の割合が少ない場合には、表４に示すように粘度が上昇するため、塗工を重ねるうちに、非常に微細な構造のノズル先端が目詰まりを起こしたと考えられる。 FIG. 5 is a diagram showing the relationship between the number of times of applying the catalyst layer and the amount of platinum applied in the catalyst layer. When the ratio of the solvent in the catalyst ink was 85% by weight, 90% by weight, and 95% by weight, the amount of platinum contained in the catalyst layer was almost constant. That is, it was found that the amount of catalyst ink sprayed was almost constant, and stable coating was possible.
On the other hand, when the ratio of the solvent in the catalyst ink was 80% by weight, the coating amount decreased. When the ratio of the solvent is small as described above, the viscosity increases as shown in Table 4. Therefore, it is considered that the nozzle tip having a very fine structure was clogged during repeated coating.

また、溶媒の割合が９８重量％の場合では、安定的な塗工量を得ることが困難であった。このように溶媒の割合が多い場合には、表４に示すように粘度が低くなるため、ノズル先端の開口度を絞っても安定した塗工量が得られ難かったと考えられる。以上より、触媒インク中の溶媒の割合は８５〜９５重量％であることが望ましいことがわかった。 Further, when the solvent ratio was 98% by weight, it was difficult to obtain a stable coating amount. When the ratio of the solvent is large as described above, the viscosity becomes low as shown in Table 4. Therefore, it is considered that it was difficult to obtain a stable coating amount even if the opening degree of the nozzle tip was reduced. From the above, it was found that the ratio of the solvent in the catalyst ink is desirably 85 to 95% by weight.

以上のように、本発明の製造方法により得られた高分子電解質型燃料電池は、家庭用コジェネレーションシステム、または自動二輪車、電気自動車、およびハイブリッド電気自動車等の電源に適用することができる。 As described above, the polymer electrolyte fuel cell obtained by the production method of the present invention can be applied to a household cogeneration system or a power source for a motorcycle, an electric vehicle, a hybrid electric vehicle, and the like.

本発明の実施例１における電池Ａおよび比較例１の電池Ｂの電流−電圧曲線を示す図である。It is a figure which shows the electric current-voltage curve of the battery A in Example 1 of this invention, and the battery B of the comparative example 1. FIG. 本発明の実施例１における電池Ａおよび比較例２の電池Ｃの電池電圧およびフッ素イオン排出量と耐久時間との関係を示す図である。It is a figure which shows the relationship between the battery voltage of the battery A of Example 1 of this invention and the battery C of the comparative example 2, and the amount of fluorine ion discharge | emission, and durable time. 本発明の実施例３における電池Ｄ〜Ｆの電流−電圧曲線を示す図である。It is a figure which shows the current-voltage curve of battery DF in Example 3 of this invention. 本発明の実施例５における電池Ｇ〜Ｈの電流−電圧曲線を示す図である。It is a figure which shows the current-voltage curve of the batteries GH in Example 5 of this invention. 本発明の触媒層の作製方法における白金塗工量と塗工回数との関係を示す図である。It is a figure which shows the relationship between the platinum coating amount and the coating frequency in the preparation method of the catalyst layer of this invention.

Claims

A method for producing a polymer electrolyte fuel cell comprising a hydrogen ion conductive polymer electrolyte membrane, and a membrane / electrode assembly composed of an electrode comprising a catalyst layer and a gas diffusion layer sandwiching the electrolyte membrane,
(1) A step of obtaining a catalyst ink including catalyst-carrying particles to which a hydrogen ion conductive polymer electrolyte is attached,
(2) A step of ejecting the catalyst ink from the nozzle and colliding the catalyst ink with a gas of ³ to 100 cm ³ per 1 mg of the catalyst ink and spraying it in the air, and (3) the mist obtained in the step (2) A method for producing a polymer electrolyte fuel cell, comprising a step of applying a catalyst ink in the form of a hydrogen ion conductive polymer electrolyte membrane disposed on a substrate to obtain a catalyst layer.

The method for producing a polymer electrolyte fuel cell according to claim 1, wherein, in the step (2), a height from the base to the opening of the nozzle is 50 to 150 mm.

The method for producing a polymer electrolyte fuel cell according to claim 1 or 2, wherein the temperature of the substrate is 30 to 70 ° C.

The method for producing a polymer electrolyte fuel cell according to claim 1, wherein in the step (1), the ratio of the solvent in the catalyst ink is 85 to 95% by weight.

The method for producing a polymer electrolyte fuel cell according to any one of claims 1 to 4, wherein an arithmetic average roughness (Ra) on the surface of the catalyst layer is 3 µm or less.