JP2007242357A - Membrane electrode assembly, and its manufacturing method - Google Patents

Membrane electrode assembly, and its manufacturing method Download PDF

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JP2007242357A
JP2007242357A JP2006061350A JP2006061350A JP2007242357A JP 2007242357 A JP2007242357 A JP 2007242357A JP 2006061350 A JP2006061350 A JP 2006061350A JP 2006061350 A JP2006061350 A JP 2006061350A JP 2007242357 A JP2007242357 A JP 2007242357A
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electrode assembly
polymer electrolyte
membrane electrode
layer
monomer
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Takashi Yamamoto
高司 山本
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Aisin Corp
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Aisin Seiki Co Ltd
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    • YGENERAL 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
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02EREDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
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    • Y02E60/30Hydrogen technology
    • Y02E60/50Fuel cells

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Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a membrane electrode assembly with a performance higher than that manufactured by hot press. <P>SOLUTION: This is a manufacturing method of a membrane electrode assembly having a polymer electrolyte layer and a pair of electrodes jointed on its both sides, and has an adhesion process having a step to form an adhesive liquid layer consisting of an adhesive liquid containing a monomer with an ion conductive functional group between the electrode and the polymer electrolyte layer, and a step to form the adhesive layer by polymerizing the monomer. In the case of a jointing method by a hot press, heating melting or the like is carried out, but it has a limit as heating at high temperature leads to deterioration of a component to constitute the membrane electrode assembly. In this manufacturing method, in jointing between polymer electrolyte layers or the like, the adhesive liquid containing the monomer is formed and then by polymerizing the monomer, they are jointed. Since the adhesive liquid is a liquid, viscosity is low, thereby, adhesion can be improved. Furthermore, since the monomer has the ion conductive functional group, conduction of protons is not blocked and a high battery performance can be achieved. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

本発明は、耐久性に優れた燃料電池が実現できる膜電極接合体及びその製造方法に関する。   The present invention relates to a membrane electrode assembly capable of realizing a fuel cell having excellent durability and a method for manufacturing the same.

固体高分子形燃料電池は主要な構成要素として膜電極接合体を有する。膜電極接合体は高分子電解質層とその両側に接合された1対の電極とを有する。高分子電解質層と電極との間には電池反応により生成するプロトンが通過するので両者の密着性は電池性能の向上に大きな影響を与える。   A polymer electrolyte fuel cell has a membrane electrode assembly as a main component. The membrane electrode assembly has a polymer electrolyte layer and a pair of electrodes bonded to both sides thereof. Since protons generated by the battery reaction pass between the polymer electrolyte layer and the electrode, the adhesion between the two greatly affects the improvement of the battery performance.

従来、高分子電解質層と電極とを接合する方法としてはホットプレスが汎用されている。ホットプレスは高分子電解質層と電極とを積層した後に加圧・加熱することで、両者の間を溶融乃至軟化させること密着させる方法である(特許文献1及び2)。
特開平5−306345号公報 特開平8−106915号公報 特開2004−253399号公報
Conventionally, hot pressing has been widely used as a method for joining a polymer electrolyte layer and an electrode. Hot pressing is a method in which a polymer electrolyte layer and an electrode are stacked and then pressurized and heated to melt or soften the two (patent documents 1 and 2).
JP-A-5-306345 JP-A-8-106915 JP 2004-253399 A

しかしながら、従来のホットプレスによる接合方法は充分な接合強度を実現しておらず、更なる改良の余地があることを本発明者は発見した。   However, the present inventors have found that the conventional hot press bonding method does not realize sufficient bonding strength and there is room for further improvement.

本発明は上記実情に鑑み完成されたものであり、従来のホットプレスにより接合した膜電極接合体よりも性能が高い膜電極接合体及びその製造方法を提供することを解決すべき課題とする。   This invention is completed in view of the said situation, and makes it the subject which should be solved to provide the membrane electrode assembly and its manufacturing method whose performance is higher than the membrane electrode assembly joined by the conventional hot press.

本発明の膜電極接合体及びその製造方法が対象とする膜電極接合体は、プロトン伝導性を有する高分子電解質層と、該高分子電解質層の両面にそれぞれ配設・接合される1対の電極と、該1対の電極の外側にそれぞれ配設・接合される1対のガス拡散層と、を有する膜電極接合体である。つまり、本明細書における「膜電極接合体」にはガス拡散層が接合されている。   The membrane / electrode assembly of the present invention and the membrane / electrode assembly targeted by the manufacturing method include a polymer electrolyte layer having proton conductivity and a pair of layers disposed and bonded to both surfaces of the polymer electrolyte layer. A membrane electrode assembly having an electrode and a pair of gas diffusion layers disposed and bonded to the outside of the pair of electrodes, respectively. That is, the gas diffusion layer is bonded to the “membrane electrode assembly” in this specification.

本発明の膜電極接合体の製造方法は、前記1対の電極のうちの少なくとも一方と前記高分子電解質層との間、及び/又は、前記1対のガス拡散層のうちの少なくとも一方と該一方のガス拡散層に接合される該電極との間に、イオン伝導性官能基をもつ単量体を含む接着液からなる1以上の接着液層を形成するステップと、該接着液層内の該単量体を重合させて接着層を形成するステップとをもつ接着工程を有することを特徴とする。   The method for producing a membrane / electrode assembly of the present invention may include at least one of the pair of electrodes and the polymer electrolyte layer and / or at least one of the pair of gas diffusion layers and the Forming one or more adhesive liquid layers composed of an adhesive liquid containing a monomer having an ion conductive functional group between the electrode bonded to one gas diffusion layer; And a step of polymerizing the monomer to form an adhesive layer.

従来のホットプレスによる接合方法では加熱溶融等行うことで、高分子電解質層と電極との間を密着させているのであるが限界がある。すなわち、より高温で加熱すると、ホットプレス時の粘度が低下して密着性が向上するが、高温での加熱は膜電極接合体を構成する構成要素の劣化につながるため限界がある。   In the conventional hot press bonding method, the polymer electrolyte layer and the electrode are brought into close contact with each other by heating and melting, but there is a limit. That is, when heated at a higher temperature, the viscosity at the time of hot pressing is reduced and the adhesion is improved. However, heating at a high temperature has a limit because it leads to deterioration of components constituting the membrane electrode assembly.

本発明の製造方法は、膜電極接合体を構成する、高分子電解質層、電極、そしてガス拡散層の間を接合するにあたり、単量体を含む接着液層を形成した後、その接着液層中の単量体を重合させることで、それらの間を接合するものである。接着液層は液体であるので低い温度でも粘度が低く、高分子電解質層及び電極などの間の密着性を向上することができる。更に、単量体はイオン伝導性官能基をもつので電池反応で生成するプロトンの伝導を阻害せず高い電池性能が実現できる。   In the production method of the present invention, in joining the polymer electrolyte layer, the electrode, and the gas diffusion layer constituting the membrane electrode assembly, after forming an adhesive liquid layer containing a monomer, the adhesive liquid layer The monomers inside are polymerized to join them. Since the adhesive liquid layer is a liquid, the viscosity is low even at a low temperature, and the adhesion between the polymer electrolyte layer and the electrode can be improved. Furthermore, since the monomer has an ion conductive functional group, high battery performance can be realized without impeding the conduction of protons generated by the battery reaction.

特に前記イオン伝導性基をもつ単量体はシアノアクリル酸誘導体であることが望ましい。シアノアクリル酸誘導体は比較的低い温度でも速やかに重合反応が進行するので高分子電解質層などを必要以上に加熱しなくても充分な接合強度をもつ膜電極接合体を製造することができる。また、シアノアクリル酸誘導体は重合触媒がない環境下では安定性が高い上に、水などの重合触媒の存在下で速やかに重合反応が進行するので重合反応の制御が容易である。   In particular, the monomer having an ion conductive group is preferably a cyanoacrylic acid derivative. Since the cyanoacrylic acid derivative rapidly undergoes a polymerization reaction even at a relatively low temperature, a membrane / electrode assembly having sufficient bonding strength can be produced without heating the polymer electrolyte layer more than necessary. In addition, the cyanoacrylic acid derivative is highly stable in an environment where there is no polymerization catalyst, and the polymerization reaction proceeds quickly in the presence of a polymerization catalyst such as water, so that the polymerization reaction can be easily controlled.

従って、シアノアクリル酸誘導体を採用する場合には、前記高分子電解質層及び前記電極の間、又は、該電極及び前記ガス拡散層の間を加圧しながら加熱するホットプレス工程を有さないことも可能である。ここで、ホットプレス工程における「加熱」とは100℃以上に加熱することをいう。100℃以上に加熱すると高分子電解質層などを構成するプロトン伝導性材料などが劣化するおそれが高まるからである。   Therefore, when a cyanoacrylic acid derivative is employed, there may be no hot pressing step of heating while pressing between the polymer electrolyte layer and the electrode or between the electrode and the gas diffusion layer. Is possible. Here, “heating” in the hot pressing step means heating to 100 ° C. or higher. This is because, when heated to 100 ° C. or higher, the proton conductive material constituting the polymer electrolyte layer or the like is likely to be deteriorated.

また、上記課題を解決する本発明の膜電極接合体は、前記1対の電極のうちの少なくとも一方と前記高分子電解質層との間、及び/又は、前記1対のガス拡散層のうちの少なくとも一方と該一方のガス拡散層に接合される該電極との間に密着・配設され、イオン伝導性官能基をもつシアノアクリル酸誘導体を重合単位として含む重合体から構成される1以上の接着層と、を有することを特徴とする。   Moreover, the membrane electrode assembly of the present invention that solves the above-mentioned problems is provided between at least one of the pair of electrodes and the polymer electrolyte layer and / or of the pair of gas diffusion layers. At least one and at least one of the electrodes bonded to the one gas diffusion layer, and one or more composed of a polymer containing a cyanoacrylic acid derivative having an ion conductive functional group as a polymerization unit. And an adhesive layer.

本発明の膜電極接合体及びその製造方法は前述したような構成を有することから以下の作用効果を発揮する。すなわち、高温で加熱しなくても低粘度であり、高分子電解質層などの表面の凹凸に容易に侵入することができるので構成要素への熱による悪影響を抑えたまま密着性を向上できる。密着性が向上すると、高分子電解質層及び電極の間などに隙間が生じ難くなり両者の間の剥がれや裂けなどの発生が抑制できるので耐久性が向上する。また、密着性が向上することでプロトン伝導が容易に進行し電池性能の向上が期待できる。更に、単量体を重合させているので高分子電解質層の表面との間で分子同士の絡み合いの発生が期待でき、耐久性が向上できる。   Since the membrane electrode assembly and the manufacturing method thereof according to the present invention have the configuration as described above, the following effects are exhibited. That is, it has a low viscosity without being heated at a high temperature and can easily penetrate into the irregularities on the surface of the polymer electrolyte layer or the like, so that the adhesion can be improved while suppressing adverse effects due to heat on the constituent elements. When the adhesion is improved, a gap is not easily formed between the polymer electrolyte layer and the electrode, and the occurrence of peeling or tearing between the two can be suppressed, so that the durability is improved. Further, by improving the adhesion, proton conduction can easily proceed, and an improvement in battery performance can be expected. Furthermore, since the monomer is polymerized, the occurrence of entanglement of molecules with the surface of the polymer electrolyte layer can be expected, and the durability can be improved.

ここで、従来技術として「接着層」を設ける技術が開示されている(特許文献3)。しかしながら、特許文献3に記載の発明における「接着層」は、請求項及び実施例の記載などから判断すると、高分子材料を溶液として塗布することで形成しており、本発明のように、高分子電解質層の表面にて単量体を重合させることで形成する層とは大きく異なるものである。つまり、単量体を含む接着液からなる接着液層を形成した後、重合させることで前述のような作用効果が期待できる。   Here, a technique of providing an “adhesive layer” is disclosed as a conventional technique (Patent Document 3). However, the “adhesive layer” in the invention described in Patent Document 3 is formed by applying a polymer material as a solution, judging from the description of the claims and the examples. This is greatly different from the layer formed by polymerizing the monomer on the surface of the molecular electrolyte layer. That is, after forming an adhesive liquid layer composed of an adhesive liquid containing a monomer, the above-described effects can be expected by polymerization.

本発明の膜電極接合体及びその製造方法について以下実施形態に基づき詳細に説明を行う。本実施形態の膜電極接合体は固体高分子形燃料電池における膜電極接合体として用いることができる。   The membrane electrode assembly of the present invention and the manufacturing method thereof will be described in detail based on the following embodiments. The membrane electrode assembly of this embodiment can be used as a membrane electrode assembly in a polymer electrolyte fuel cell.

(膜電極接合体の製造方法)
本実施形態の膜電極接合体の製造方法が対象とする膜電極接合体は高分子電解質層と電極とガス拡散層とを有する。高分子電解質層の両側に電極が接合されている。ガス拡散層は高分子電解質層の両側に接合された電極を更に外側から挟み込むように接合されている。
(Method for producing membrane electrode assembly)
The membrane electrode assembly targeted by the method for producing a membrane electrode assembly of the present embodiment has a polymer electrolyte layer, an electrode, and a gas diffusion layer. Electrodes are bonded to both sides of the polymer electrolyte layer. The gas diffusion layer is joined so that the electrodes joined to both sides of the polymer electrolyte layer are further sandwiched from the outside.

高分子電解質層はプロトン伝導性を有する高分子材料であるプロトン伝導性材料から構成される。プロトン伝導性材料としては特に限定しないがスルホ基、リン酸基、カルボキシル基などのイオン伝導性官能基を分子構造中に有する材料が例示される。例えば、ナフィオン(商標)などに代表されるパーフルオロ系の電解質材料や、スチレンなどのベンゼン環をもつ単量体を重合した材料にスルホ基を導入した材料のような炭化水素系の電解質材料などが例示できる。そして、水素の一部がフッ素原子にて置換された炭化水素系の材料からなる電解質を採用することもできる。また、有機系の材料の他にもシリカなどにイオン伝導性官能基を導入した無機系の電解質、更には有機−無機の複合材料からなる電解質を採用することもできる。高分子電解質層はプロトン伝導性材料を適正な溶媒などにて溶解した後、表面が平滑な材料表面に塗布し乾燥するなどの方法にて薄膜化することで形成することができる。下記、電極についても同様に形成できる。   The polymer electrolyte layer is composed of a proton conductive material that is a polymer material having proton conductivity. Although it does not specifically limit as a proton conductive material, The material which has ion conductive functional groups, such as a sulfo group, a phosphate group, and a carboxyl group, in a molecular structure is illustrated. For example, perfluoro-based electrolyte materials represented by Nafion (trademark), etc., and hydrocarbon-based electrolyte materials such as materials obtained by polymerizing a monomer having a benzene ring such as styrene with a sulfo group introduced Can be illustrated. An electrolyte made of a hydrocarbon-based material in which a part of hydrogen is substituted with fluorine atoms can also be employed. In addition to organic materials, inorganic electrolytes obtained by introducing ion conductive functional groups into silica or the like, and electrolytes composed of organic-inorganic composite materials can also be employed. The polymer electrolyte layer can be formed by dissolving the proton conductive material in an appropriate solvent, etc., and then applying a thin film to the surface of the smooth material and drying it. The following electrodes can be formed similarly.

電極についても特に限定しないが、電池反応を起こさせる貴金属触媒とその貴金属触媒を分散するプロトン伝導性材料とを有するものが例示できる。貴金属触媒は炭素系の材料から構成される微粒子の表面に担持した状態とすることもできる。電極が含有するプロトン伝導性材料についても特に限定しないが、高分子電解質層にて説明したプロトン伝導性材料と同様の材料を採用することもできる。   Although it does not specifically limit also about an electrode, What has the noble metal catalyst which raise | generates a battery reaction and the proton conductive material which disperse | distributes the noble metal catalyst can be illustrated. The noble metal catalyst may be supported on the surface of fine particles composed of a carbon-based material. The proton conductive material contained in the electrode is not particularly limited, but the same material as the proton conductive material described in the polymer electrolyte layer can be used.

ガス拡散層も特に限定しないが、カーボンペーパー単独や、カーボンペーパーにプロトン伝導性材料を塗布したものなどが例示できる。また、カーボンペーパーの一面側に前述の電極と一体となったガス拡散層を採用することもできる。   The gas diffusion layer is not particularly limited, and examples thereof include carbon paper alone or carbon paper coated with a proton conductive material. Further, a gas diffusion layer integrated with the above-described electrode can be employed on one side of the carbon paper.

本実施形態の膜電極接合体の製造方法は、前述した方法など、何らかの方法にて製造された高分子電解質層及び電極、及び/又は電極及びガス拡散層の間を接着する接着工程を有する。接着工程を適用する対象としては高分子電解質層及びその両面に接合される電極との間の双方ともに適用されることが望ましいが、一方の電極にのみに適用しても良い。また、ガス拡散層を有する場合にはガス拡散層及びそのガス拡散層に接合される電極との間にも適用することができる。以下、説明の便宜のために、接着工程を適用する対象の高分子電解質層及び電極、又は、ガス拡散層及び電極についてすべて「対象膜」と称することがある。   The manufacturing method of the membrane electrode assembly of the present embodiment includes a bonding step of bonding between the polymer electrolyte layer and the electrode and / or the electrode and the gas diffusion layer manufactured by any method such as the method described above. As an object to which the bonding process is applied, it is desirable that both the polymer electrolyte layer and the electrodes bonded to both sides thereof are applied, but it may be applied to only one electrode. Moreover, when it has a gas diffusion layer, it can apply also between a gas diffusion layer and the electrode joined to the gas diffusion layer. Hereinafter, for convenience of explanation, the polymer electrolyte layer and electrode to which the adhesion process is applied, or the gas diffusion layer and electrode may all be referred to as “target membrane”.

接着工程は接着液層形成ステップと接着層形成ステップとをもつ。接着液層形成ステップは接着する対象膜の間に接着液からなる接着液層を形成するステップである。接着液はイオン伝導性基をもつ単量体(イオン伝導性基含有単量体)を含む。イオン伝導性基含有単量体のほかにもイオン伝導性基をもたない単量体やこれらの単量体を溶解する溶媒を含有することもできる。また、単量体を重合させるために重合開始剤を含有することもできる。重合開始剤としては熱重合開始剤が望ましい。光照射が適正に可能であれば光重合開始剤を採用することも望ましい。接着液は対象膜の表面への密着性を向上する目的で、取り扱いが容易である限り低粘度であることが望ましい。接着液としてはイオン伝導性基含有単量体及びイオン伝導性基を含まない単量体の混合物を採用することが望ましく、更にはイオン伝導性基含有単量体を単独で採用することがより望ましい。   The bonding process includes an adhesive liquid layer forming step and an adhesive layer forming step. The adhesive liquid layer forming step is a step of forming an adhesive liquid layer made of an adhesive liquid between target films to be bonded. The adhesive liquid contains a monomer having an ion conductive group (an ion conductive group-containing monomer). In addition to the ion-conducting group-containing monomer, a monomer having no ion-conducting group and a solvent for dissolving these monomers can also be contained. Moreover, in order to polymerize a monomer, a polymerization initiator can also be contained. As the polymerization initiator, a thermal polymerization initiator is desirable. It is also desirable to employ a photopolymerization initiator if light irradiation is properly possible. For the purpose of improving the adhesion to the surface of the target film, the adhesive liquid desirably has a low viscosity as long as it can be easily handled. As the adhesive liquid, it is desirable to employ a mixture of an ion conductive group-containing monomer and a monomer that does not contain an ion conductive group, and more preferably an ion conductive group-containing monomer alone. desirable.

イオン伝導性基含有単量体がもつイオン伝導性基としては特に限定しないが、スルホ基、カルボキシル基、リン酸官能基などが例示できる。特にスルホ基がイオン伝導性向上の目的には望ましい。イオン伝導性基含有単量体としてはシアノアクリル酸誘導体を採用することが望ましい。シアノアクリル酸誘導体は室温でも微量の水などの存在下、簡単に重合が進行する上に高温での加熱などを行うことも必須ではなくある。従って、対象膜の間の接合を行う際に加圧しながら加熱するホットプレス工程を採用しなくても充分な接合強度が実現できる。ここで、ホットプレス工程における「加熱」とは100℃以上に加熱することをいうが更には70℃以上に加熱することを避けることがより望ましい。プロトン伝導性材料などの劣化をより効果的に防ぐことができるからである。   Although it does not specifically limit as an ion conductive group which an ion conductive group containing monomer has, A sulfo group, a carboxyl group, a phosphoric acid functional group etc. can be illustrated. In particular, a sulfo group is desirable for the purpose of improving ion conductivity. It is desirable to employ a cyanoacrylic acid derivative as the ion conductive group-containing monomer. It is not essential that the cyanoacrylic acid derivative is easily polymerized in the presence of a small amount of water at room temperature and further heated at a high temperature. Therefore, sufficient bonding strength can be realized without adopting a hot press step of heating while applying pressure when bonding between target films. Here, “heating” in the hot pressing step means heating to 100 ° C. or higher, but it is more desirable to avoid heating to 70 ° C. or higher. This is because deterioration of the proton conductive material or the like can be prevented more effectively.

イオン伝導性基をもつシアノアクリル酸誘導体は、シアノアクリル酸のカルボニル基に対して、エステル化、アミド化などを行うことによりイオン伝導性基を導入した化合物である。特に、アルキレン基などの炭化水素基を介してイオン伝導性基を導入することで、イオン伝導性基の運動性が向上してイオン伝導性基の配置が適正化できるので望ましい。好ましいイオン伝導性基含有単量体としてはCH=CH(CN)CONH(CHSOHやCH=CH(CN)CONH−C−SOHが例示できる。 A cyanoacrylic acid derivative having an ion conductive group is a compound in which an ion conductive group is introduced by performing esterification, amidation, or the like on the carbonyl group of cyanoacrylic acid. In particular, introduction of an ion conductive group through a hydrocarbon group such as an alkylene group is desirable because the mobility of the ion conductive group is improved and the arrangement of the ion conductive group can be optimized. Preferable examples of the ion conductive group-containing monomer include CH 2 ═CH (CN) CONH (CH 2 ) 2 SO 3 H and CH 2 ═CH (CN) CONH—C 6 H 4 —SO 3 H.

接着層形成ステップは接着液中に含まれるイオン伝導性基含有単量体などを重合させて接着層を形成するステップである。つまり、接着層はイオン伝導性基含有単量体を重合単位として含む重合体である。   The adhesive layer forming step is a step of forming an adhesive layer by polymerizing an ion conductive group-containing monomer or the like contained in the adhesive liquid. That is, the adhesive layer is a polymer containing an ion conductive group-containing monomer as a polymerization unit.

重合は含有するイオン伝導性基含有単量体及び含有されることがあるその他の単量体の種類や含有させた重合開始剤の種類に応じて適正な方法が異なるが、相対的に低温で反応が進行するものが望ましい。接着層形成ステップは対象膜の間の密着性を向上する目的で加圧下で行うことが望ましい。   The appropriate method varies depending on the type of the ion-conducting group-containing monomer and the other monomer that may be contained and the type of polymerization initiator that is contained, but at relatively low temperatures. It is desirable that the reaction proceeds. The adhesive layer forming step is desirably performed under pressure for the purpose of improving the adhesion between the target films.

例えば、イオン伝導性基含有単量体としてシアノアクリル酸誘導体を採用する場合には僅かに水分が存在する環境下にて放置することで重合反応が進行する。この水分は対象膜の表面に予め付着させておくこともできる。例えば、対象膜の一方の表面にイオン伝導性基含有単量体を塗布し、対象膜の他方の表面には水を僅かに付着させた上で両者を密着させることで重合させる方法である。   For example, when a cyanoacrylic acid derivative is employed as the ion conductive group-containing monomer, the polymerization reaction proceeds by leaving it in an environment where there is a slight amount of water. This moisture can be previously attached to the surface of the target film. For example, an ion conductive group-containing monomer is applied to one surface of the target film, and the other surface of the target film is polymerized by adhering a little water to the other surface.

また、乾燥雰囲気下で双方の対象膜の表面にイオン伝導性基含有単量体を塗布した後に双方を密着させ、湿度が有る程度高い雰囲気下に放置することで重合反応を進行させることもできる。この重合反応は本接着工程において完全に終了させなくても本製造方法にて製造された膜電極接合体を燃料電池に適用した際に、電池反応で生成する水分に接触することになるので、電池中で重合反応を完了できる。なお、対象膜の間の密着性を向上するには対象膜の双方に接着液を塗布することが望ましい。ここで、接着液層の厚みとしては対象膜の間の密着性を向上させるのに充分な厚みが確保できる程度で且つできるだけ薄いことが望ましい。例えば、1μm以上、10μm以下程度の範囲から選択されることが望ましい。   In addition, after applying an ion conductive group-containing monomer to the surfaces of both target films in a dry atmosphere, both can be brought into close contact with each other, and the polymerization reaction can proceed by leaving it in an atmosphere having a high humidity level. . Even if this polymerization reaction is not completely terminated in the present adhesion step, when the membrane electrode assembly produced by this production method is applied to a fuel cell, it will come into contact with moisture generated by the cell reaction. The polymerization reaction can be completed in the battery. In order to improve the adhesion between the target films, it is desirable to apply an adhesive liquid to both of the target films. Here, it is desirable that the thickness of the adhesive liquid layer be as thin as possible to ensure a sufficient thickness for improving the adhesion between the target films. For example, it is desirable to select from a range of about 1 μm or more and 10 μm or less.

(膜電極接合体)
本実施形態の膜電極接合体は、前述の製造方法にて製造された膜電極接合体のうち、接着層を構成する重合単位の1つとしてイオン伝導性基をもつシアノアクリル酸誘導体を有するものである。その他の構成については膜電極接合体の製造方法にて説明したものと同様なので省略する。
(Membrane electrode assembly)
The membrane electrode assembly of this embodiment has a cyanoacrylic acid derivative having an ion conductive group as one of the polymerized units constituting the adhesive layer among the membrane electrode assemblies manufactured by the above-described manufacturing method. It is. Other configurations are the same as those described in the method for manufacturing a membrane electrode assembly, and thus are omitted.

本発明の膜電極接合体及びその製造方法について以下実施例に基づき詳細に説明を行う。イオン伝導性基含有単量体として、CH=CH(CN)CONH(CHSOHで表される単量体を採用して以下の試験を行った。この単量体はイオン伝導性基としてスルホ基をもつシアノアクリル酸誘導体である。 The membrane electrode assembly of the present invention and the production method thereof will be described in detail based on the following examples. As an ion-conducting group-containing monomer, it was adopted by the following tests a monomer represented by CH 2 = CH (CN) CONH (CH 2) 2 SO 3 H. This monomer is a cyanoacrylic acid derivative having a sulfo group as an ion conductive group.

(イオン伝導性基含有単量体の合成)
シアノアクリル酸(CH=CH(CN)COOH)0.2gを脱水したテトラヒドロフラン(THF)20mL中に投入し0℃で30分間撹拌を行い完全に溶解させた。次に反応触媒として、ジシクロヘキシルカルボジイミド(DCC)を1g加えて1時間撹拌を行った。
(Synthesis of ion-conducting group-containing monomer)
Cyanoacrylic acid (CH 2 ═CH (CN) COOH) 0.2 g was put into 20 mL of dehydrated tetrahydrofuran (THF) and stirred at 0 ° C. for 30 minutes for complete dissolution. Next, 1 g of dicyclohexylcarbodiimide (DCC) was added as a reaction catalyst and stirred for 1 hour.

脱水したTHF20mL中にアミノエタンスルホン酸(HN(CHSOH)0.4gを加えて30分間撹拌して溶解させた溶液を上記シアノアクリル酸溶液中に滴下することでシアノアクリル酸にスルホ基を導入したスルホン化シアノアクリル酸誘導体:CH=CH(CN)CONH(CHSOHを得た。その後、24時間反応後、10℃のエーテル中に滴下することで再結晶を行い精製した。なお、アミノエタンスルホン酸に代えてp−アミノベンゼンスルホン酸を採用することもできる。 A solution prepared by adding 0.4 g of aminoethanesulfonic acid (H 2 N (CH 2 ) 2 SO 3 H) in 20 mL of dehydrated THF and stirring and dissolving for 30 minutes was added dropwise to the cyanoacrylic acid solution to add cyano. A sulfonated cyanoacrylic acid derivative having a sulfo group introduced into acrylic acid: CH 2 ═CH (CN) CONH (CH 2 ) 2 SO 3 H was obtained. Then, after reacting for 24 hours, it was recrystallized by being dropped into ether at 10 ° C. for purification. Note that p-aminobenzenesulfonic acid may be employed instead of aminoethanesulfonic acid.

(膜電極接合体の製造:実施例)
高分子電解質層(Nafion112)の表面に前述のスルホン化シアノアクリル酸誘導体を塗布した後、電極(電極面積130cm)を接合させた。接合条件は2MPaの圧力で3分間、室温でプレスを行った。その後、ガス拡散層の表面にも前述のスルホン化シアノアクリル酸誘導体を塗布した後、2MPaの圧力で3分間、室温でプレスを行った。電極及びガス拡散層の製造方法は後述する。
(Manufacture of membrane electrode assembly: Examples)
The aforementioned sulfonated cyanoacrylic acid derivative was applied to the surface of the polymer electrolyte layer (Nafion 112), and then an electrode (electrode area 130 cm 2 ) was bonded thereto. The bonding conditions were pressing at a pressure of 2 MPa for 3 minutes at room temperature. Then, after apply | coating the above-mentioned sulfonated cyanoacrylic acid derivative also to the surface of a gas diffusion layer, it pressed at room temperature for 3 minutes with the pressure of 2 MPa. The manufacturing method of an electrode and a gas diffusion layer is mentioned later.

(膜電極接合体の製造:比較例)
高分子電解質層(Nafion112)及び電極(電極面積130cm)をホットプレス(圧力10MPa、1分間、150℃)で接合した。その後、ガス拡散層をホットプレス(圧力8MPa、3分間、140℃)で接合した。
(Manufacture of membrane electrode assembly: comparative example)
The polymer electrolyte layer (Nafion 112) and the electrode (electrode area 130 cm 2 ) were joined by hot pressing (pressure 10 MPa, 1 minute, 150 ° C.). Then, the gas diffusion layer was joined by hot pressing (pressure 8 MPa, 3 minutes, 140 ° C.).

(電極の製造)
カソード側の電極:白金担持カーボン(T10E70TPM:田中貴金属製、Pt67質量%)10g、SS-1100/05(イオン交換樹脂5質量%、旭化成製)82.5g、そしてイオン交換水34gを混合し、サンドミル(ジルコニアボール2Φmm、周速15m/s)にて1分間分散しペースト化した(イオン交換樹脂/PtC中のC=1.25)。このペーストをETFE(厚み50μm)上に、ギャップ250μmに調整したドクターブレードを用い塗布した。得られた電極は触媒Ptの担持量が1.0mg/cm2であった。
(Manufacture of electrodes)
Cathode side electrode: Platinum-supported carbon (T10E70TPM: Tanaka Kikinzoku, Pt67 mass%) 10 g, SS-1100 / 05 (ion exchange resin 5 mass%, Asahi Kasei) 82.5 g, and ion-exchanged water 34 g were mixed. The mixture was dispersed for 1 minute in a sand mill (zirconia ball 2Φmm, peripheral speed 15 m / s) to form a paste (C in ion-exchange resin / PtC = 1.25). This paste was applied onto ETFE (thickness 50 μm) using a doctor blade adjusted to a gap of 250 μm. The obtained electrode had a supported amount of catalyst Pt of 1.0 mg / cm 2 .

アノード側の電極:白金ルテニウム担持カーボン(TEC62E58、田中貴金属製、Pt27.2質量%、Ru28.8質量%、原子比Pt:Ru=1:2)10g、SS-1100/05が110g、そしてイオン交換水34gを混合し、サンドミル(ジルコニアボール2Φmm、周速15m/s)にて1分間分散しペースト化した(イオン交換樹脂/PtC中のC=1.25)。このペーストをETFE(厚み50μm)上に、ギャップ150μmに調整したドクターブレードを用い塗布した。得られた電極は触媒Ptの担持量が0.20mg/cm2であった。 Anode-side electrode: platinum ruthenium-supported carbon (TEC62E58, Tanaka Kikinzoku, Pt 27.2 mass%, Ru 28.8 mass%, atomic ratio Pt: Ru = 1: 2) 10 g, SS-1100 / 05 110 g, and ions 34 g of exchange water was mixed and dispersed for 1 minute in a sand mill (zirconia balls 2Φ mm, peripheral speed 15 m / s) to form a paste (C in ion exchange resin / PtC = 1.25). This paste was applied onto ETFE (thickness 50 μm) using a doctor blade adjusted to a gap of 150 μm. The obtained electrode had a supported amount of catalyst Pt of 0.20 mg / cm 2 .

(ガス拡散層の製造)
カーボンペーパ(TGP−H−60、厚み190μm、東レ製)に撥水カーボンペーストを含浸させ、70℃で予備乾燥を行った後、330℃で1時間焼成することでガス拡散層を得た。撥水カーボンペーストは、カーボンペースト(御国色素製、カーボン固形分23質量%、含有するカーボンはバルカンXC−72R(キャボット製))と、カーボンペースト中のカーボン固形分100質量部に対し、固形分換算で75質量部のポリフロンD1(ダイキン工業製、固形分60質量%)とを混合・撹拌した調製した。
(Manufacture of gas diffusion layer)
Carbon paper (TGP-H-60, thickness 190 μm, manufactured by Toray) was impregnated with a water-repellent carbon paste, preliminarily dried at 70 ° C., and then fired at 330 ° C. for 1 hour to obtain a gas diffusion layer. The water-repellent carbon paste is composed of carbon paste (manufactured by Gokoku Dye, carbon solid content of 23% by mass, carbon contained in Vulcan XC-72R (made by Cabot)) and carbon solid content in the carbon paste of 100 parts by mass. It was prepared by mixing and stirring 75 parts by mass of Polyflon D1 (made by Daikin Industries, solid content 60% by mass) in terms of conversion.

(電池の耐久試験)
実施例及び比較例の膜電極接合体を用い、燃料電池セルを作成した。この燃料電池に対してサイクル試験を行った後に膜電極接合体を評価した。サイクル試験は電流密度0.1A/cmと0.4A/cmとの間でそれぞれ1分間ずつ運転を行うサイクルを100時間連続して行った。燃料電池の運転条件としては以下の通りである。セル温度は70℃とした。アノード側のガスは、50℃の水中でバブリングを行った後に50℃として供給した。カソード側のガスは、45℃の水中でバブリングを行った後に45℃として供給した。ガス利用率はアノード側を80%、カソード側を50%とした。
(Battery durability test)
Using the membrane electrode assemblies of Examples and Comparative Examples, fuel cells were prepared. After performing a cycle test on this fuel cell, the membrane electrode assembly was evaluated. Cycle test was conducted a cycle of performing the operation one each minute between the current density 0.1 A / cm 2 and 0.4 A / cm 2 continuously for 100 hours. The operating conditions of the fuel cell are as follows. The cell temperature was 70 ° C. The gas on the anode side was supplied as 50 ° C. after bubbling in water at 50 ° C. The gas on the cathode side was supplied as 45 ° C. after bubbling in water at 45 ° C. The gas utilization was 80% on the anode side and 50% on the cathode side.

耐久試験後の各膜電極接合体を観察したところ、実施例の膜電極接合体は特に剥がれがなかったのに対して、比較例の膜電極接合体では高分子電解質層及び電極の間での剥がれが観察された。   When each membrane electrode assembly after the durability test was observed, the membrane electrode assembly of the example was not particularly peeled, whereas in the membrane electrode assembly of the comparative example, it was between the polymer electrolyte layer and the electrode. Peeling was observed.

(接合力の評価)
実施例の膜電極接合体に相当する試験試料として、2枚の高分子電解質層(Nafion112)の間を前述のスルホン化シアノアクリル酸誘導体にて接合した試料を用意した。接合条件は圧力1MPa、3分間、25℃でプレスすることで行った。
(Evaluation of bonding strength)
As a test sample corresponding to the membrane electrode assembly of the example, a sample was prepared in which two polymer electrolyte layers (Nafion 112) were joined with the sulfonated cyanoacrylic acid derivative described above. The joining conditions were performed by pressing at a pressure of 1 MPa for 3 minutes at 25 ° C.

比較例の膜電極接合体に相当する試験試料として、2枚の高分子電解質層(Nafion112)の間をホットプレスにて接合した試料を用意した。ホットプレスの条件は圧力1MPa、3分間、140℃で行った。   As a test sample corresponding to the membrane electrode assembly of the comparative example, a sample was prepared in which two polymer electrolyte layers (Nafion 112) were joined by hot pressing. The hot pressing was performed at a pressure of 1 MPa for 3 minutes at 140 ° C.

試験;これら実施例及び比較例の試験試料をそれぞれ5つずつ用意して、剥離試験を行った。剥離試験は70℃の水中で、接合した2枚の高分子電解質層を剥離する方向に引っ張る際の力を測定することで強度を測定した。   Test: Five test samples of each of these examples and comparative examples were prepared, and a peel test was performed. In the peel test, the strength was measured by measuring the force when pulling the joined two polymer electrolyte layers in the direction of peeling in 70 ° C. water.

結果:実施例の試験試料は接合強度が6.57N(0.67kgf)であり、比較例の試験試料は1.37N(0.14kgf)であり、実施例の試験試料の方が比較例の試験試料よりも高い接合強度を示すことが明らかになった。   Results: The test sample of the example has a bond strength of 6.57 N (0.67 kgf), the test sample of the comparative example is 1.37 N (0.14 kgf), and the test sample of the example is the comparative example. It was revealed that the bonding strength was higher than that of the test sample.

以上の結果より、スルホン化シアノアクリル酸誘導体にて接合を行う実施例の試験試料はホットプレスにて接合を行う比較例の試験試料よりも接合強度が高くなることが明らかになり、その結果、電池に適用した場合の耐久性も向上することが明らかになった。   From the above results, it becomes clear that the test sample of the example bonded with the sulfonated cyanoacrylic acid derivative has higher bonding strength than the test sample of the comparative example bonded with hot press, It has been clarified that the durability when applied to a battery is improved.

Claims (4)

プロトン伝導性を有する高分子電解質層と、該高分子電解質層の両面にそれぞれ配設・接合される1対の電極と、該1対の電極の外側にそれぞれ配設・接合される1対のガス拡散層と、を有する膜電極接合体を製造する方法であって、
前記1対の電極のうちの少なくとも一方と前記高分子電解質層との間、及び/又は、前記1対のガス拡散層のうちの少なくとも一方と該一方のガス拡散層に接合される該電極との間に、イオン伝導性官能基をもつ単量体を含む接着液からなる1以上の接着液層を形成するステップと、該接着液層内の該単量体を重合させて接着層を形成するステップとをもつ接着工程を有することを特徴とする膜電極接合体の製造方法。
A polymer electrolyte layer having proton conductivity, a pair of electrodes disposed and bonded to both surfaces of the polymer electrolyte layer, and a pair of electrodes disposed and bonded to the outside of the pair of electrodes, respectively A method for producing a membrane electrode assembly having a gas diffusion layer,
The electrode bonded between at least one of the pair of electrodes and the polymer electrolyte layer and / or at least one of the pair of gas diffusion layers and the one gas diffusion layer; A step of forming one or more adhesive liquid layers made of an adhesive liquid containing a monomer having an ion conductive functional group, and polymerizing the monomers in the adhesive liquid layer to form an adhesive layer And a manufacturing method of a membrane electrode assembly, characterized by comprising a bonding step.
前記イオン伝導性基をもつ単量体はシアノアクリル酸誘導体である請求項1に記載の膜電極接合体の製造方法。   The method for producing a membrane electrode assembly according to claim 1, wherein the monomer having an ion conductive group is a cyanoacrylic acid derivative. 前記高分子電解質層及び前記電極の間、又は、該電極及び前記ガス拡散層の間を加圧しながら加熱するホットプレス工程を有さない請求項2に記載の膜電極接合体の製造方法。   The manufacturing method of the membrane electrode assembly of Claim 2 which does not have a hot press process heated while pressing between the said polymer electrolyte layer and the said electrode, or between this electrode and the said gas diffusion layer. プロトン伝導性を有する高分子電解質層と、該高分子電解質層の両面にそれぞれ配設・接合される1対の電極と、該1対の電極の外側にそれぞれ配設・接合される1対のガス拡散層と、を有する膜電極接合体であって、
前記1対の電極のうちの少なくとも一方と前記高分子電解質層との間、及び/又は、前記1対のガス拡散層のうちの少なくとも一方と該一方のガス拡散層に接合される該電極との間に密着・配設され、イオン伝導性官能基をもつシアノアクリル酸誘導体を重合単位として含む重合体から構成される1以上の接着層と、
を有することを特徴とする膜電極接合体。
A polymer electrolyte layer having proton conductivity, a pair of electrodes disposed and bonded to both surfaces of the polymer electrolyte layer, and a pair of electrodes disposed and bonded to the outside of the pair of electrodes, respectively A membrane electrode assembly having a gas diffusion layer,
The electrode bonded between at least one of the pair of electrodes and the polymer electrolyte layer and / or at least one of the pair of gas diffusion layers and the one gas diffusion layer; One or more adhesive layers composed of a polymer containing a cyanoacrylic acid derivative having an ion conductive functional group as a polymerization unit,
A membrane electrode assembly comprising:
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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2017082050A (en) * 2015-10-23 2017-05-18 関西ペイント株式会社 Coating Composition

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2017082050A (en) * 2015-10-23 2017-05-18 関西ペイント株式会社 Coating Composition

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