JP2011060775A - Gas diffusion layer, fuel cell electrode, and fuel cell - Google Patents

Gas diffusion layer, fuel cell electrode, and fuel cell Download PDF

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JP2011060775A
JP2011060775A JP2010254384A JP2010254384A JP2011060775A JP 2011060775 A JP2011060775 A JP 2011060775A JP 2010254384 A JP2010254384 A JP 2010254384A JP 2010254384 A JP2010254384 A JP 2010254384A JP 2011060775 A JP2011060775 A JP 2011060775A
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fuel cell
gas diffusion
diffusion layer
peak
electrode
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JP5174128B2 (en
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Masataka Kadowaki
正天 門脇
Shunsuke Taniguchi
俊輔 谷口
Takahiro Isono
隆博 礒野
Yasuo Miyake
泰夫 三宅
Koji Nishio
晃治 西尾
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Sanyo Electric Co Ltd
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    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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Abstract

<P>PROBLEM TO BE SOLVED: To provide a gas diffusion layer suppressing deterioration in battery characteristics with time including deterioration in a battery voltage, to provide a fuel cell electrode, and to provide a fuel cell. <P>SOLUTION: In a gas diffusion layer formed by filling conductive powder in pores of a porous body subjected to water repellent treatment, a distribution of pore diameters has a first peak existing in a range of 1-100 μm and a second peak existing in a range of 15 nm-1 μm. Since the fist peak is higher than the second peak, deterioration in battery characteristics with time can be suppressed. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

本発明は、ガス拡散層、燃料電池用電極及び燃料電池に関する。 The present invention relates to a gas diffusion layer, a fuel cell electrode, and a fuel cell .

一般に固体高分子型燃料電池は、図７の構造断面図に示す如く、固体高分子電解質膜１を挟んで燃料側の電極２と酸化剤側の電極３とを対峙させて一体化することにより厚さ０.２〜０.５ｍｍ程度の単位セルＵＣを形成し、そしてこのような単位セルＵＣを複数個積層して燃料電池とされている。   In general, a polymer electrolyte fuel cell is obtained by integrating a fuel-side electrode 2 and an oxidant-side electrode 3 so as to face each other with a solid polymer electrolyte membrane 1 interposed therebetween, as shown in the structural cross-sectional view of FIG. A unit cell UC having a thickness of about 0.2 to 0.5 mm is formed, and a plurality of such unit cells UC are stacked to form a fuel cell.

そして、燃料として水素リッチのガスを、また酸化剤として空気等の酸素リッチのガスを供給することにより、電力を発生させている。   Electric power is generated by supplying a hydrogen-rich gas as a fuel and an oxygen-rich gas such as air as an oxidant.

斯かる従来の固体高分子型燃料電池においては、燃料側及び酸化剤側の電極２，３として、通常撥水処理の施されたカーボンペーパー等の多孔質体からなるガス拡散層２Ｂ，３Ｂ上に、貴金属触媒を担持した炭素粉末とフッ素樹脂とを混合してなる触媒層２Ａ，３Ａを接合させたものが用いられている。   In such a conventional polymer electrolyte fuel cell, the electrodes 2 and 3 on the fuel side and the oxidant side are usually provided on the gas diffusion layers 2B and 3B made of a porous material such as carbon paper subjected to water repellent treatment. In addition, the catalyst layers 2A and 3A formed by mixing a carbon powder carrying a noble metal catalyst and a fluororesin are used.

然し乍ら、従来の固体高分子型燃料電池においては、発電時間の経過に伴って次第に電池電圧が低下する傾向があり、特に上記のように撥水処理の施されたガス拡散層を用いた場合には、その傾向が顕著である。   However, in the conventional polymer electrolyte fuel cell, the battery voltage tends to gradually decrease with the lapse of power generation time, particularly when the gas diffusion layer subjected to the water repellent treatment as described above is used. The tendency is remarkable.

そこで、本発明は、電池電圧の低下を始めとする電池特性の経時的な低下という課題を低減することのできるガス拡散層、燃料電池用電極及び燃料電池を提供することを目的とする。 Accordingly, an object of the present invention is to provide a gas diffusion layer, a fuel cell electrode, and a fuel cell, which can reduce the problem of a decrease in battery characteristics over time, including a decrease in battery voltage.

上記従来の課題を解決するために、本発明のガス拡散層は、撥水処理を施した多孔質体の気孔に導電性粉末を充填してなるガス拡散層であって、気孔径分布は、１μｍ〜１００μｍの範囲に存在する第１のピークと、１５ｎｍ〜１μｍの範囲に存在する第２のピークと、を有し、前記第１のピークは、前記第２のピークに比べて高いことを特徴とする。 In order to solve the above conventional problems, the gas diffusion layer of the present invention is a gas diffusion layer formed by filling pores of a porous body subjected to water repellent treatment with conductive powder, and the pore size distribution is: A first peak present in the range of 1 μm to 100 μm and a second peak present in the range of 15 nm to 1 μm, wherein the first peak is higher than the second peak Features.

また、前記第２のピークは、２０ｎｍ〜１００ｎｍの範囲に存在することを特徴とする。The second peak is present in the range of 20 nm to 100 nm.

また、前記導電性粉末は、撥水性樹脂により前記気孔内に結着されていることを特徴とする。Further, the conductive powder is bound in the pores by a water repellent resin.

また、前記撥水性樹脂は、フッ素樹脂であることを特徴とする。The water repellent resin is a fluororesin.
また、前記フッ素樹脂は、テトラフルオロエチレン−ヘキサフルオロプロピレン共重合体であることを特徴とする。The fluororesin is a tetrafluoroethylene-hexafluoropropylene copolymer.
また、前記導電性粉末は、炭素粉末であることを特徴とする。The conductive powder is carbon powder.

また、本発明の燃料電池用電極は、上記のガス拡散層と、前記ガス拡散層に接合される触媒層と、を有することを特徴とする。Moreover, the electrode for fuel cells of this invention has said gas diffusion layer and a catalyst layer joined to the said gas diffusion layer, It is characterized by the above-mentioned.
また、前記気孔径分布は、５ｎｍ〜１０ｎｍの範囲に存在する第３のピークを更に有することを特徴とする。The pore size distribution further includes a third peak existing in a range of 5 nm to 10 nm.

また、本発明の燃料電池は、燃料側電極と、酸化剤側電極と、前記燃料側電極と前記酸化剤電極との間に位置する電解質層と、を備える燃料電池であって、少なくとも前記燃料側電極は、上記の燃料電池用電極であることを特徴とする。The fuel cell of the present invention is a fuel cell comprising a fuel-side electrode, an oxidant-side electrode, and an electrolyte layer positioned between the fuel-side electrode and the oxidant electrode, wherein at least the fuel The side electrode is the fuel cell electrode described above.

以上説明した如く、本発明によれば電池特性の経時的な低下を抑制でき、安定性の向上した燃料電池を提供することができる。   As described above, according to the present invention, it is possible to provide a fuel cell that can suppress a decrease in battery characteristics over time and has improved stability.

燃料電池用電極の気孔径分布を示す特性図である。It is a characteristic view which shows the pore diameter distribution of the electrode for fuel cells. 実施例１に係るガス拡散層Ａの気孔径分布を示す特性図である。6 is a characteristic diagram showing a pore size distribution of a gas diffusion layer A according to Example 1. FIG. 実施例２に係る燃料電池用電極Ｂの気孔径分布を示す特性図である。6 is a characteristic diagram showing a pore size distribution of a fuel cell electrode B according to Example 2. FIG. 比較例に係るガス拡散層Ｃの気孔径分布を示す特性図である。It is a characteristic view which shows the pore diameter distribution of the gas diffusion layer C which concerns on a comparative example. 比較例に係る燃料電池用電極Ｃの気孔径分布を示す特性図である。It is a characteristic view which shows the pore diameter distribution of the electrode C for fuel cells which concerns on a comparative example. 燃料電池の電池電圧の経時変化を示す特性図である。It is a characteristic view which shows a time-dependent change of the battery voltage of a fuel cell. 従来の燃料電池の構造を示す断面構造図である。It is a sectional view showing the structure of a conventional fuel cell.

以下に、本発明に係る燃料電池用電極について説明する。
図１は、本発明燃料電池用電極の気孔径分布を島津製作所製ポアサイザ９３１０を使用して水銀圧入法により測定した結果を示す特性図である。尚、同図において実線Ａ及びＢは共に本発明燃料電池用電極の測定結果であり、また破線Ｃは従来の燃料電池用電極の測定結果である。 The fuel cell electrode according to the present invention will be described below.
FIG. 1 is a characteristic diagram showing the result of measuring the pore size distribution of the fuel cell electrode of the present invention by mercury porosimetry using a pore sizer 9310 manufactured by Shimadzu Corporation. In the figure, solid lines A and B are the measurement results of the fuel cell electrode of the present invention, and the broken line C is the measurement result of the conventional fuel cell electrode.

同図に示す如く、破線Ｃで示した従来の燃料電池用電極においては１μｍ〜１００μｍの範囲に１つのピークが観測されるだけである。これに対し、本発明燃料電池用電極の場合には、上記１μｍ〜１００μｍの範囲にある第１のピークの他に、実線Ａで示す本発明燃料電池用電極にあっては１５ｎｍ〜１μｍの範囲にもブロードな第２のピークが新たに観測され、また、実線Ｂで示す本発明燃料電池用電極にあっては２０ｎｍ〜１００ｎｍの範囲に比較的シャープな第２のピークが新たに観測される。このように、従来の燃料電池用電極にあっては１μｍ〜１００μｍの気孔径を有する比較的大口径の気孔しかなかったのに対し、本発明の燃料電池用電極にあっては上記大口径の気孔に加えて、気孔径１５ｎｍ〜１μｍ或いは２０ｎｍ〜１００ｎｍの比較的小口径の気孔も存在している。   As shown in the figure, in the conventional fuel cell electrode indicated by the broken line C, only one peak is observed in the range of 1 μm to 100 μm. On the other hand, in the case of the fuel cell electrode of the present invention, in addition to the first peak in the range of 1 μm to 100 μm, the fuel cell electrode of the present invention indicated by the solid line A has a range of 15 nm to 1 μm. In addition, a broad second peak is newly observed, and in the fuel cell electrode of the present invention indicated by the solid line B, a relatively sharp second peak is newly observed in the range of 20 nm to 100 nm. . As described above, the conventional fuel cell electrode has only a relatively large pore having a pore diameter of 1 μm to 100 μm, whereas the fuel cell electrode of the present invention has the above large diameter. In addition to the pores, there are pores having a relatively small diameter of 15 nm to 1 μm or 20 nm to 100 nm.

そして、このような第１のピークと第２のピークとを持つ気孔径分布を有する燃料電池用電極を用いることで、本発明によれば電池電圧の低下を始めとする電池特性の経時的な低下が抑制され、信頼性の向上した燃料電池を提供することができる。   Then, by using the fuel cell electrode having the pore size distribution having the first peak and the second peak as described above, according to the present invention, the battery characteristics such as a decrease in battery voltage over time can be obtained. It is possible to provide a fuel cell in which the decrease is suppressed and the reliability is improved.

また、１μｍ〜１００μｍの範囲に存在する第１のピークと、１５ｎｍ〜１μｍの範囲に存在するブロードな第２のピーク、或いは２０ｎｍ〜１００ｎｍの範囲に存在する比較的シャープな第２のピークとを有するガス拡散層を用いた電極であれば、上記のような気孔径分布を有する燃料電池用電極が得られる。   In addition, a first peak existing in the range of 1 μm to 100 μm, a broad second peak existing in the range of 15 nm to 1 μm, or a relatively sharp second peak existing in the range of 20 nm to 100 nm. If it is an electrode using the gas diffusion layer which has, the electrode for fuel cells which has the above pore diameter distribution is obtained.

即ち、燃料電池用電極は、ロール法によって形成された触媒層をガス拡散層上に配置して接合させる方法、或いはスクリーン印刷法、噴霧法等の方法によってガス拡散層上に直接触媒槽を形成して接合させる方法等によって製造されるが、燃料電池用電極の気孔径分布にはガス拡散層の気孔径分布が反映され、ガス拡散層と殆ど同じ分布が得られるのである。 In other words, for fuel cell electrodes, the catalyst layer formed by the roll method is placed on the gas diffusion layer and bonded, or the catalyst tank is formed directly on the gas diffusion layer by methods such as screen printing and spraying. However, the pore size distribution of the fuel cell electrode reflects the pore size distribution of the gas diffusion layer, and almost the same distribution as that of the gas diffusion layer is obtained.

さらに、撥水処理の施されたカーボンペーパー等の多孔質体に炭素粉末のような導電性粉末が充填されたガス拡散層によれば、上記のような気孔径分布を有するガス拡散層が提供される。即ち、充填された導電性粉末が、撥水性処理の施された多孔質体中に存在する１μｍ〜１００μｍの気孔径を有する比較的大口径の気孔中に充填されることにより、径が１５ｎｍ〜１μｍ或いは２０ｎｍ〜１００ｎｍの比較的小口径の気孔が新たに生成されるのである。   Furthermore, according to the gas diffusion layer in which a porous material such as carbon paper subjected to water repellent treatment is filled with conductive powder such as carbon powder, the gas diffusion layer having the pore size distribution as described above is provided. Is done. That is, the filled conductive powder is filled in pores having a relatively large diameter having a pore diameter of 1 μm to 100 μm present in the porous body subjected to the water repellent treatment, so that the diameter is 15 nm to A pore having a relatively small diameter of 1 μm or 20 nm to 100 nm is newly generated.

また、斯かる燃料電池用電極は、以下のようにして製造することができる。   Moreover, such a fuel cell electrode can be manufactured as follows.

まず、カーボン織布、カーボン不織布のような多孔質体に、従来と同様にして撥水処理を施す。例えば多孔質体を、ポリテトラフルオロエチレン（ＰＴＦＥ）、テトラフルオロエチレン−ヘキサフルオロプロピレン共重合体（ＦＥＰ）等の撥水性樹脂の分散液に浸漬後、乾燥、焼成することにより撥水処理を施す。   First, a water repellent treatment is applied to a porous body such as a carbon woven fabric or a carbon non-woven fabric in the same manner as before. For example, the porous body is immersed in a water-repellent resin dispersion such as polytetrafluoroethylene (PTFE) or tetrafluoroethylene-hexafluoropropylene copolymer (FEP), and then dried and fired to give a water-repellent treatment. .

そして、本発明においては、このように撥水処理の施された多孔質体に炭素粉末のような導電性粉末を充填し、ガス拡散層とする。   In the present invention, the porous body subjected to the water repellent treatment is filled with conductive powder such as carbon powder to form a gas diffusion layer.

充填する導電性粉末としては炭素粉末以外に金属粉末を用いても良いが、固体高分子型燃料電池の運転時には反応ガス中に含まれる水分が電極中を流れることとなる。この際、上記導電性粉末が水分に腐食されるような材質のものであると電極の特性を劣化させることとなるために、上記導電性粉末は炭素粉末のように水に対する耐腐食性を有するものであることが好ましく、この点から炭素粉末が最も好ましい。   As the conductive powder to be filled, a metal powder may be used in addition to the carbon powder. However, when the solid polymer fuel cell is operated, moisture contained in the reaction gas flows through the electrode. At this time, if the conductive powder is made of a material that is corroded by moisture, the characteristics of the electrode are deteriorated. Therefore, the conductive powder has corrosion resistance to water like carbon powder. From this point, carbon powder is most preferable.

また、このような導電性粉末を多孔質体に充填する方法としては、例えば導電性粉末をフッ素樹脂と混合することにより作製したペーストを多孔質体上に塗布し、そしてヘラを用いて圧力を加えながら多孔質体中に塗り込む、といった方法を用いることができる。この際に、多孔質体中に塗り込むペーストの量が少ないと、上記第２のピークは１５ｎｍ〜１μｍの範囲に存在するブロードなピークとなり、塗り込む量を多くすると２０ｎｍ〜１００ｎｍの範囲に存在する比較的シャープなピークとなる。 Moreover, as a method of filling such a conductive powder in the porous body, for example, a paste prepared by mixing the conductive powder with a fluororesin is applied onto the porous body, and the pressure is applied using a spatula. It is possible to use a method of coating in the porous body while adding. At this time, if the amount of paste applied in the porous body is small, the second peak becomes a broad peak existing in the range of 15 nm to 1 μm, and if the amount applied is large, it exists in the range of 20 nm to 100 nm. A relatively sharp peak.

尚、上記フッ素樹脂は、導電性粉末の結着剤としての役割を果たすものであり、撥水処理の施された多孔質体中に充填されるものであることから基本性能として撥水性を有することが求められる。このように導電性粉末の結着剤としての役割を果たし、さらに撥水性を有するものとしてはフッ素樹脂が好ましく、具体的にはＦＥＰ、ＰＴＦＥ、ＥＴＦＥ（テトラフルオロエチレン−エチレン共重合体）、パーフルオロスルホン酸樹脂等を用いることができる。この中でも特にＦＥＰを用いることにより導電性粉末を多孔質体の厚み方向の深部にまで充填することが可能となるので好ましい。   The fluororesin plays a role as a binder for the conductive powder and has a water repellency as a basic performance since it is filled in a porous body subjected to a water repellent treatment. Is required. Thus, the fluororesin is preferable as a binder for the conductive powder and has water repellency. Specifically, FEP, PTFE, ETFE (tetrafluoroethylene-ethylene copolymer), par A fluorosulfonic acid resin or the like can be used. Among these, it is particularly preferable to use FEP because it is possible to fill the conductive powder into a deep portion in the thickness direction of the porous body.

そして、このように導電性粉末の充填されたガス拡散層上に、従来と同様にして触媒層を接合することにより、本発明燃料電池用電極が製造される。   The fuel cell electrode of the present invention is manufactured by joining the catalyst layer on the gas diffusion layer filled with the conductive powder in the same manner as in the prior art.

ここで、触媒層としては、例えば気孔率７５％のカーボンペーパーに、炭素粉末表面に白金微粒子を担持させてなる触媒粉末と結着剤としてのＰＴＦＥとを混合して形成した触媒ペーストを、スプレー法、濾過法、ドクターブレード法或いはリバースロールコータ法等の方法を用いて塗布後、乾燥・焼成したものを用いることができる。   Here, as the catalyst layer, for example, a catalyst paste formed by mixing a carbon paper having a porosity of 75% with a catalyst powder in which platinum fine particles are supported on the carbon powder surface and PTFE as a binder is sprayed. After drying using a method such as a method, a filtration method, a doctor blade method or a reverse roll coater method, a dried and baked product can be used.

そして、このようにして形成した触媒層とガス拡散層とを、プレスまたはロール法等の方法を用いて圧接することにより接合することができる。   And the catalyst layer and gas diffusion layer which were formed in this way can be joined by press-contacting using methods, such as a press or a roll method.

或いは、上記触媒粉末とナフィオン溶液とを混合して作製したペースト状の触媒層をスクリーン印刷法により直接ガス拡散層上に形成し、接合させても良い。   Alternatively, a paste-like catalyst layer prepared by mixing the catalyst powder and the Nafion solution may be directly formed on the gas diffusion layer by screen printing and bonded.

以上の様にして、本発明燃料電池用電極が製造される。   As described above, the fuel cell electrode of the present invention is manufactured.

ところで、本発明により電池電圧の低下を始めとする電池特性の経時的な低下が抑制され、信頼性の向上した燃料電池を提供することができる理由は現在のところ明らかではないが、以下のような理由が推測される。   By the way, the reason why the present invention can provide a fuel cell in which the deterioration of battery characteristics such as a decrease in battery voltage over time is suppressed and the reliability is improved is not clear at present. The reason is guessed.

固体高分子型燃料電池に使用される固体高分子電解質膜は、水で膨潤された状態でないとイオン導電性を示さない。そのため、固体高分子型燃料電池では、６０〜１００℃で加湿した燃料ガス及び／又は酸化剤、或いは燃料ガスと共に水を導入し、電解質膜への水の供給を行っている。   A solid polymer electrolyte membrane used in a solid polymer fuel cell does not exhibit ionic conductivity unless it is swollen with water. Therefore, in the polymer electrolyte fuel cell, water is introduced together with the fuel gas and / or oxidant humidified at 60 to 100 ° C. or the fuel gas, and water is supplied to the electrolyte membrane.

ところで、このような水の供給は電極を介して行なわれるために、水が電極中に存在している１μｍ〜１００μｍの気孔径を有する比較的大口径の気孔中に滞留し、このために従来においては燃料或いは酸化剤の拡散が阻害されて、電池特性の経時的な低下が生じるものと考えられる。   By the way, since such water supply is performed through the electrodes, the water stays in the pores of a relatively large diameter having a pore diameter of 1 μm to 100 μm existing in the electrodes. In this case, it is considered that the diffusion of fuel or oxidant is hindered and the battery characteristics deteriorate with time.

一方、本発明によれば上記大口径の気孔以外に、径が１５ｎｍ〜１μｍ或いは２０ｎｍ〜１００ｎｍの比較的小口径の気孔も存在している。従って本発明によれば、例え水が比較的大口径の気孔中に滞留したとしても、小口径の気孔を介してガスが拡散可能であるために、電池特性の経時的な低下を抑制できたものと推察される。   On the other hand, according to the present invention, there are pores having a relatively small diameter of 15 nm to 1 μm or 20 nm to 100 nm in addition to the large diameter pores. Therefore, according to the present invention, even if water stays in pores having a relatively large diameter, gas can be diffused through the pores having a small diameter, so that deterioration in battery characteristics over time can be suppressed. Inferred.

尚、一般に多孔質体が水に接する場合、径が小さい孔ほど浸透圧現象にて水を吸収しやすいとされているが、この現象は多孔質材料と水との濡れ性が良い場合に生じる現象であり、本発明のように撥水処理の施された多孔質体にあてはまるものではない。   In general, when the porous body is in contact with water, it is said that the smaller the diameter, the more easily water is absorbed by the osmotic pressure phenomenon. This phenomenon occurs when the wettability between the porous material and water is good. This phenomenon does not apply to a porous body that has been subjected to water repellent treatment as in the present invention.

以下に、本発明の実施例について説明する。
（実施例１）
カーボンペーパーからなる多孔質体をＦＥＰの１６ｗｔ％アルコール溶液からなるフッ素樹脂ディスパージョンに浸漬し、これを３８０℃で１時間乾燥、焼成することにより撥水処理を施した。そして、このように撥水処理の施された多孔質体に、さらにカーボン粉末（ＶｕｌｃａｎＸＣ７２Ｒ）とフッ素樹脂とを混合したペーストを塗り込みガス拡散層Ａを作製した。 Examples of the present invention will be described below.
Example 1
A porous body made of carbon paper was immersed in a fluororesin dispersion made of a 16 wt% alcohol solution of FEP, and this was dried and fired at 380 ° C. for 1 hour to give a water repellent treatment. And the paste which mixed carbon powder (VulcanXC72R) and fluororesin was further apply | coated to the porous body to which the water repellent process was performed in this way, and the gas diffusion layer A was produced.

このガス拡散層Ａの気孔径分布を、島津製作所製ポアサイザ９３１０を使用し水銀圧入法にて測定した結果を図２の特性図に示す。同図に示すように気孔径のピークが１μｍ〜１００μｍと２０ｎｍ〜１００ｎｍに存在した。   The result of measuring the pore size distribution of the gas diffusion layer A by a mercury intrusion method using a pore sizer 9310 manufactured by Shimadzu Corporation is shown in the characteristic diagram of FIG. As shown in the figure, the pore diameter peaks existed at 1 to 100 μm and 20 to 100 nm.

また、白金担持カーボンとＮａｆｉｏｎ５ｗｔ％溶液とＰＴＦＥとを６７．９：２．１：３０の重量比で混合し、ロール法を用いて作製した２枚の触媒層シート間に、固体高分子電解質膜（Ｎａｆｉｏｎ１１２）を挟んでホットプレス法により接合した。   Also, a solid polymer electrolyte membrane is formed between two catalyst layer sheets prepared by using a roll method by mixing platinum-supporting carbon, a Nafion 5 wt% solution, and PTFE at a weight ratio of 67.9: 2.1: 30. Joined by hot pressing with (Nafion 112) in between.

そして、このようにして形成した接合体の両面を夫々上記ガス拡散層Ａで挟み圧接することにより、燃料電池Ａを作製した。
（実施例２）
上記ガス拡散層Ａ表面に、白金担持カーボンとＮａｆｉｏｎ５ｗｔ％溶液とＰＴＦＥとを８７．６：２．４：２０の重量比で混合して形成した触媒ペーストをスクリーン印刷法により塗布し、燃料電池用電極Ｂとした。 Then, the fuel cell A was manufactured by sandwiching and pressing the gas diffusion layer A on both surfaces of the joined body thus formed.
(Example 2)
A catalyst paste formed by mixing platinum-supported carbon, Nafion 5 wt% solution, and PTFE in a weight ratio of 87.6: 2.4: 20 is applied to the surface of the gas diffusion layer A by a screen printing method. Electrode B was designated.

この燃料電池用電極Ｂの気孔径分布を測定した結果を図３の特性図に示す。図２及び図３の比較から明らかな通り、燃料電池用電極Ｂの気孔径分布にはガス拡散層Ａの気孔径分布が反映され、ガス拡散層Ａと殆ど同じ分布が得られている。また、ガス拡散層Ａで観測されたピークに加えて５ｎｍ〜１０ｎｍの範囲に小さく第３のピークが観測された。   The result of measuring the pore size distribution of the fuel cell electrode B is shown in the characteristic diagram of FIG. As apparent from the comparison between FIG. 2 and FIG. 3, the pore size distribution of the fuel cell electrode B reflects the pore size distribution of the gas diffusion layer A, and almost the same distribution as the gas diffusion layer A is obtained. In addition to the peak observed in the gas diffusion layer A, a small third peak was observed in the range of 5 nm to 10 nm.

さらに、上記のようにして形成した燃料側及び酸化剤側の燃料電池用電極の間に固体高分子膜（Ｎａｆｉｏｎ１１２）を挟み、ホットプレス法により接合して燃料電池Ｂを作製した。
（比較例）
カーボンペーパーからなる多孔質体をＦＥＰの１６ｗｔ％アルコール溶液からなるフッ素樹脂ディスパージョンに浸漬し、これを３８０℃で1時間乾燥、焼成することにより撥水処理を施して、比較用のガス拡散層Ｃを作製した。 Further, a fuel cell B was fabricated by sandwiching a solid polymer membrane (Nafion 112) between the fuel cell electrodes formed as described above and the oxidant side fuel cell electrodes and joining them by hot pressing.
(Comparative example)
A porous material made of carbon paper is immersed in a fluororesin dispersion made of a 16 wt% alcohol solution of FEP, dried and baked at 380 ° C. for 1 hour to give a water repellent treatment, and a gas diffusion layer for comparison C was produced.

このガス拡散層Ｃの気孔径分布は、図４の特性図に示す如く、１μｍ〜１００μｍの範囲にのみピークが観測された。   In the pore diameter distribution of the gas diffusion layer C, a peak was observed only in the range of 1 μm to 100 μm, as shown in the characteristic diagram of FIG.

また、上記ガス拡散層Ｃ表面に、白金担持カーボンとＮａｆｉｏｎ５ｗｔ％溶液とＰＴＦＥとを８７．６：２．４：２０の重量比で混合して形成した触媒ペーストをスクリーン印刷にて塗布し、燃料電池用電極Ｃを作成した。   Further, a catalyst paste formed by mixing platinum supporting carbon, a Nafion 5 wt% solution, and PTFE in a weight ratio of 87.6: 2.4: 20 is applied to the surface of the gas diffusion layer C by screen printing. A battery electrode C was prepared.

この燃料電池用電極Ｃの気孔径分布を測定した結果、図５の特性図に示す如く、ガス拡散層Ｃで観測されたピーク（図４参照）に加えて５ｎｍ〜１０ｎｍの範囲に小さいピークが観測されるものの、１５ｎｍ〜１μｍの範囲にはピークは観測されなかった。 As a result of measuring the pore size distribution of the fuel cell electrode C, as shown in the characteristic diagram of FIG. 5, in addition to the peak observed in the gas diffusion layer C (see FIG. 4), there is a small peak in the range of 5 nm to 10 nm. Although observed, no peak was observed in the range of 15 nm to 1 μm .

さらに、上記のようにして形成した燃料側及び酸化剤側の燃料電池用電極Ｃの間に固体高分子膜（Ｎａｆｉｏｎ１１２）を挟み、ホットプレス法により接合して燃料電池Ｃを作製した。   Further, a fuel cell C was fabricated by sandwiching a solid polymer film (Nafion 112) between the fuel cell electrode C and the oxidant side fuel cell C formed as described above and joining them by a hot press method.

そして、以上の様にして作製した燃料電池Ａ，Ｂ及びＣを以下の運転条件で運転し、夫々の電池電圧の経時変化を測定した。その結果を図６の特性図に示す。
[運転条件]
燃料：純水素(８０℃加湿)、Uf（燃料利用率）＝70%
酸化剤：空気(７４℃加湿)、Uox（酸化剤利用率）＝40%
電流密度０.５A/cm2
図６から明らかに、本発明に係る燃料電池Ａ及びＢは５０００時間を過ぎても電池電圧の低下が生じず、従来の燃料電池Ｃに比べて電池特性の経時的な低下を抑制することができた。 Then, the fuel cells A, B, and C produced as described above were operated under the following operating conditions, and changes with time in the respective battery voltages were measured. The result is shown in the characteristic diagram of FIG.
[Operating conditions]
Fuel: Pure hydrogen (80 ° C humidification), Uf (fuel utilization rate) = 70%
Oxidizing agent: Air (74 ° C humidification), Uox (oxidizing agent utilization rate) = 40%
Current density 0.5A / cm 2
As is apparent from FIG. 6, the fuel cells A and B according to the present invention do not cause a decrease in battery voltage even after 5000 hours, and suppress the deterioration in battery characteristics over time as compared with the conventional fuel cell C. did it.

このように、本発明により電池特性の経時的な低下を抑制できた理由は、前述したように本発明の燃料電池用電極にあっては大口径の気孔に加えて、気孔径１５ｎｍ〜１μｍ或いは２０ｎｍ〜１００ｎｍの比較的小口径の気孔も存在し、この小口径の気孔を介してガスが拡散するために、電池特性の経時的な低下を抑制できたものと推察される。   As described above, the reason why the present invention has been able to suppress the deterioration of the battery characteristics with time is that, in the fuel cell electrode according to the present invention, in addition to the large pores, the pore size is 15 nm to 1 μm or Since pores having a relatively small diameter of 20 nm to 100 nm are also present and gas diffuses through the pores having a small diameter, it is presumed that the deterioration of battery characteristics over time can be suppressed.

尚、上記の実施例においては、第２のピークが２０ｎｍ〜１００ｎｍの範囲に存在するガス拡散層或いは燃料電池用電極を用いている。この第２のピークの存在する範囲は、前述の通り撥水処理の施された多孔質体に、導電性粉末を塗り込む際の塗り込み量を調整することにより変化させることができ、塗り込み量を少なくすることで１５ｎｍ〜１μｍの範囲にブロードなピークが現れる。   In the above embodiment, the gas diffusion layer or the fuel cell electrode having the second peak in the range of 20 nm to 100 nm is used. The range in which the second peak exists can be changed by adjusting the amount of the conductive powder applied to the porous body that has been subjected to the water repellent treatment as described above. By reducing the amount, a broad peak appears in the range of 15 nm to 1 μm.

斯かるブロードなピークを有する燃料電池用電極であっても同様に、電池特性の経時的な低下を抑制することができるが、まれに電池電圧が数ｍＶ〜数十ｍＶ低下するものが生じるため、安定性から考えて、第２のピークが２０ｎｍ〜１００ｎｍの範囲に存在するものの方が好ましい。   Similarly, even with such a fuel cell electrode having a broad peak, it is possible to suppress the deterioration of the battery characteristics over time, but in rare cases, the battery voltage decreases by several mV to several tens of mV. From the viewpoint of stability, it is preferable that the second peak exists in the range of 20 nm to 100 nm.

また、上記の実施例においては燃料側及び酸化剤側の両方に本発明に係る燃料電池用電極を用いたが、燃料側のみに加湿された燃料ガス或いは燃料ガスと同時に水を導入し、酸化剤側には加湿されない酸化剤を導入する燃料電池においては、燃料側にのみ本発明に係る燃料電池用電極を用いるようにしても良い。この場合にあっても電池特性の経時的な低下を抑制することができる。   In the above embodiment, the fuel cell electrode according to the present invention is used on both the fuel side and the oxidant side. However, humidified fuel gas or fuel gas is introduced only on the fuel side, and water is introduced simultaneously to oxidize. In a fuel cell in which an oxidant that is not humidified is introduced on the agent side, the fuel cell electrode according to the present invention may be used only on the fuel side. Even in this case, the deterioration of the battery characteristics over time can be suppressed.

１ 固体高分子電解質膜、２ 電極、２Ａ 触媒層、２Ｂ ガス拡散層、３ 電極、３Ａ 触媒層、３Ｂ ガス拡散層1 solid polymer electrolyte membrane, 2 electrodes, 2A catalyst layer, 2B gas diffusion layer, 3 electrodes, 3A catalyst layer, 3B gas diffusion layer

Claims (9)

撥水処理を施した多孔質体の気孔に導電性粉末を充填してなるガス拡散層であって、A gas diffusion layer formed by filling pores of a porous body subjected to water repellent treatment with conductive powder,
気孔径分布は、１μｍ〜１００μｍの範囲に存在する第１のピークと、１５ｎｍ〜１μｍの範囲に存在する第２のピークと、を有し、  The pore size distribution has a first peak present in the range of 1 μm to 100 μm and a second peak present in the range of 15 nm to 1 μm,
前記第１のピークは、前記第２のピークに比べて高いことを特徴とする、ガス拡散層。  The gas diffusion layer, wherein the first peak is higher than the second peak. 前記第２のピークは、２０ｎｍ〜１００ｎｍの範囲に存在することを特徴とする、請求項１に記載のガス拡散層。The gas diffusion layer according to claim 1, wherein the second peak exists in a range of 20 nm to 100 nm. 前記導電性粉末は、撥水性樹脂により前記気孔内に結着されていることを特徴とする、請求項１または２に記載のガス拡散層。The gas diffusion layer according to claim 1, wherein the conductive powder is bound in the pores with a water repellent resin. 前記撥水性樹脂は、フッ素樹脂であることを特徴とする、請求項３に記載のガス拡散層。The gas diffusion layer according to claim 3, wherein the water repellent resin is a fluororesin. 前記フッ素樹脂は、テトラフルオロエチレン−ヘキサフルオロプロピレン共重合体であることを特徴とする、請求項４に記載のガス拡散層。The gas diffusion layer according to claim 4, wherein the fluororesin is a tetrafluoroethylene-hexafluoropropylene copolymer. 前記導電性粉末は、炭素粉末であることを特徴とする、請求項１から５のいずれかに記載のガス拡散層。The gas diffusion layer according to claim 1, wherein the conductive powder is carbon powder. 請求項１から６のいずれかに記載のガス拡散層と、前記ガス拡散層に接合される触媒層と、を有することを特徴とする、燃料電池用電極。An electrode for a fuel cell comprising the gas diffusion layer according to any one of claims 1 to 6 and a catalyst layer bonded to the gas diffusion layer. 前記気孔径分布は、５ｎｍ〜１０ｎｍの範囲に存在する第３のピークを更に有することを特徴とする、請求項７に記載の燃料電池用電極。The fuel cell electrode according to claim 7, wherein the pore size distribution further has a third peak existing in a range of 5 nm to 10 nm. 燃料側電極と、酸化剤側電極と、前記燃料側電極と前記酸化剤電極との間に位置する電解質層と、を備える燃料電池であって、A fuel cell comprising a fuel side electrode, an oxidant side electrode, and an electrolyte layer located between the fuel side electrode and the oxidant electrode,
少なくとも前記燃料側電極は、請求項７または８に記載の燃料電池用電極であることを特徴とする、燃料電池。  9. The fuel cell according to claim 7, wherein at least the fuel side electrode is a fuel cell electrode according to claim 7.
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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH06295728A (en) * 1993-04-08 1994-10-21 Matsushita Electric Ind Co Ltd Electrode for solid high polymer type fuel cell and fuel cell using it
JPH0992293A (en) * 1995-09-26 1997-04-04 Matsushita Electric Ind Co Ltd Electrode for solid polymer, type fuel cell and fuel cell using this electrode
JPH09265993A (en) * 1996-03-29 1997-10-07 Mazda Motor Corp Solid polymer type fuel cell
JPH103929A (en) * 1996-03-23 1998-01-06 Degussa Ag Gas diffusing electrode for membrane fuel cell and its manufacture
JPH10261421A (en) * 1997-03-17 1998-09-29 Japan Gore Tex Inc Gas diffusion layer material for high polymer solid electrolyte fuel cell and junction thereof

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH06295728A (en) * 1993-04-08 1994-10-21 Matsushita Electric Ind Co Ltd Electrode for solid high polymer type fuel cell and fuel cell using it
JPH0992293A (en) * 1995-09-26 1997-04-04 Matsushita Electric Ind Co Ltd Electrode for solid polymer, type fuel cell and fuel cell using this electrode
JPH103929A (en) * 1996-03-23 1998-01-06 Degussa Ag Gas diffusing electrode for membrane fuel cell and its manufacture
JPH09265993A (en) * 1996-03-29 1997-10-07 Mazda Motor Corp Solid polymer type fuel cell
JPH10261421A (en) * 1997-03-17 1998-09-29 Japan Gore Tex Inc Gas diffusion layer material for high polymer solid electrolyte fuel cell and junction thereof

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