JP2020149895A - Fuel battery cell and manufacturing method thereof - Google Patents

Fuel battery cell and manufacturing method thereof Download PDF

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JP2020149895A
JP2020149895A JP2019047325A JP2019047325A JP2020149895A JP 2020149895 A JP2020149895 A JP 2020149895A JP 2019047325 A JP2019047325 A JP 2019047325A JP 2019047325 A JP2019047325 A JP 2019047325A JP 2020149895 A JP2020149895 A JP 2020149895A
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川角　明人
Akito Kawakado
明人 川角
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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

To provide a manufacturing method of gas diffusion layer for fuel cell, restraining deterioration of gas diffusion property in a porous base material layer.SOLUTION: In a manufacturing method of fuel battery cell 10 comprising a gas diffusion layer 6 for fuel cell including a porous base material layer 5 and a microporous layer 4, and a separator 7, while bringing the convex part of a member having an irregular shape into contact with one surface of the porous base material layer 5, the other surface is coated with coating liquid for water repellent treatment and thermally dried, subsequently the surface on the opposite side is coated with the coating liquid for microporous layer formation, and then heated and calcined. Thereafter, the separator 7 having an irregular shape is placed on the opposite surface to the surface coated with the coating liquid for microporous layer formation. The separator is placed so that the convex part thereof comes into contact with the location facing the location where the convex part of the member having the irregular shape of the porous base material is brought into contact.SELECTED DRAWING: Figure 1

Description

本発明は、燃料電池セル及びその製造方法に関する。 The present invention relates to a fuel cell and a method for manufacturing the same.

燃料電池は、電気的に接続された２つの電極に燃料ガス（水素ガス）と酸化剤ガス（酸素ガス）を供給し、電気化学的に燃料の酸化を起こさせることで、化学エネルギーを直接電気エネルギーに変換する。この燃料電池は、通常、電解質膜を一対の電極で挟持した膜電極接合体を基本構造とする燃料電池セル（単セル）を複数積層して構成されている。中でも、電解質膜として固体高分子電解質膜を用いた固体高分子電解質型燃料電池は、小型化が容易であること、低い温度で作動すること、などの利点があることから、特に携帯用、移動体用電源として注目されている。 A fuel cell supplies chemical energy directly to electricity by supplying fuel gas (hydrogen gas) and oxidant gas (oxygen gas) to two electrically connected electrodes and electrochemically causing oxidation of the fuel. Convert to energy. This fuel cell is usually configured by stacking a plurality of fuel cell cells (single cells) having a membrane electrode assembly in which an electrolyte membrane is sandwiched between a pair of electrodes. Among them, the polymer electrolyte electrolyte fuel cell using the polymer electrolyte membrane as the electrolyte membrane has advantages such as easy miniaturization and operation at a low temperature, so that it is particularly portable and mobile. It is attracting attention as a body power source.

固体高分子電解質型燃料電池において、水素が供給されたアノード（燃料極）では下記（１）式の反応が進行する。
Ｈ２ → ２Ｈ＋ ＋ ２ｅ− ・・・（１） In the polymer electrolyte fuel cell, the reaction of the following formula (1) proceeds at the anode (fuel electrode) to which hydrogen is supplied.
H 2 → 2H + + 2e - ··· (1)

上記（１）式で生じる電子は、外部回路を経由し、外部の負荷で仕事をした後、カソード（酸化剤極）に到達する。他方で、上記（１）式で生じたプロトンは、水と水和した状態で、電気浸透により固体高分子電解質膜内をアノード側からカソード側に移動する。 The electrons generated by the above equation (1) reach the cathode (oxidizing agent electrode) after working under an external load via an external circuit. On the other hand, the protons generated by the above equation (1) move from the anode side to the cathode side in the solid polymer electrolyte membrane by electroosmosis in a state of being hydrated with water.

一方、カソードでは下記（２）式の反応が進行する。
２Ｈ＋ ＋ １／２Ｏ２ ＋ ２ｅ− → Ｈ２Ｏ ・・・（２） On the other hand, at the cathode, the reaction of the following equation (2) proceeds.
2H ＋ ＋ 1 / 2O 2 ＋ 2e − → H 2 O ・ ・ ・ (2)

従って、電池全体では下記（３）に示す化学反応が進行し、起電力が生じて外部負荷に対して電気的仕事がなされる。
Ｈ２ ＋ １／２Ｏ２ → Ｈ２Ｏ ・・・（３） Therefore, the chemical reaction shown in (3) below proceeds in the entire battery, electromotive force is generated, and electrical work is performed on the external load.
H 2 + 1 / 2O 2 → H 2 O ・ ・ ・ (3)

アノード及びカソードの各電極は、一般的に、電解質膜側から順に触媒層、ガス拡散層が積層した構造を有する。触媒層には、通常、上記電極反応を促進させるための白金や白金合金等の電極触媒、プロトン伝導性を確保するための高分子電解質、電子伝導性を確保するための導電性材料が含まれている。また、ガス拡散層は、通常、触媒層への反応ガスの供給、電極中の余剰の水分の排出等を可能とする導電性多孔質体を用いて形成される。 Each electrode of the anode and the cathode generally has a structure in which a catalyst layer and a gas diffusion layer are laminated in this order from the electrolyte membrane side. The catalyst layer usually contains an electrode catalyst such as platinum or a platinum alloy for promoting the electrode reaction, a polymer electrolyte for ensuring proton conductivity, and a conductive material for ensuring electron conductivity. ing. Further, the gas diffusion layer is usually formed by using a conductive porous body capable of supplying the reaction gas to the catalyst layer, discharging excess water in the electrode, and the like.

パーフルオロカーボンスルホン酸樹脂膜に代表される固体高分子電解質膜を備えた燃料電池では、イオン伝導性を確保するために、電解質膜や触媒層の湿潤状態を維持することが重要である。そのため、一般的に、反応ガスを予め加湿した状態で電極に供給することが行われている。 In a fuel cell provided with a solid polymer electrolyte membrane represented by a perfluorocarbon sulfonic acid resin membrane, it is important to maintain a wet state of the electrolyte membrane and the catalyst layer in order to ensure ionic conductivity. Therefore, in general, the reaction gas is supplied to the electrode in a pre-humidified state.

一方で、燃料電池では、上記したように、発電に伴って水が生成する。生成した水の多くは、電極から排出される未反応ガス（電極反応に寄与しなかった反応ガス）や水蒸気として供給される加湿水と共に、セル外へと排出される。しかしながら、生成水や、反応ガスと共に電極に水蒸気として供給された加湿水の一部は、燃料電池内の環境によっては凝縮し、電極内に液体の状態で存在することになる。このとき、凝縮した水（液水）が電極内に滞留すると液水がつまり、いわゆるフラッディングが起きて、反応ガスの供給が妨げられ、発電性能が低下してしまう。特に、燃料電池を高加湿条件下で運転する場合には、液水が多く発生するため、電極の液水の排出性を確保する必要がある。 On the other hand, in a fuel cell, as described above, water is generated along with power generation. Most of the generated water is discharged to the outside of the cell together with the unreacted gas (reaction gas that did not contribute to the electrode reaction) discharged from the electrode and the humidified water supplied as water vapor. However, a part of the generated water and the humidified water supplied as water vapor to the electrode together with the reaction gas is condensed depending on the environment in the fuel cell and exists in the electrode in a liquid state. At this time, if the condensed water (liquid water) stays in the electrode, the liquid water is clogged, that is, so-called flooding occurs, the supply of the reaction gas is hindered, and the power generation performance deteriorates. In particular, when the fuel cell is operated under high humidification conditions, a large amount of liquid water is generated, so it is necessary to ensure the discharge of liquid water from the electrodes.

従って、電極内の液水を、速やかにセル外へと排出し、電極内での滞留を防止することが望まれている。 Therefore, it is desired that the liquid water in the electrode is quickly discharged to the outside of the cell to prevent the liquid water from staying in the electrode.

このフラッディングを抑制するためのガス拡散層として、多孔質構造を有する多孔質基材層に、多孔質基材層よりも小さな細孔径を有する微細多孔質層（もしくはマイクロポーラス層とも呼ぶ）が積層された構造を有するものが知られている。この微細多孔質層を設けることにより、微細多孔質層の極微細な多孔質構造が液水膜の形成を阻害し、ガス拡散層の排水性を向上させるとされている。 As a gas diffusion layer for suppressing this flooding, a microporous layer (also referred to as a microporous layer) having a pore diameter smaller than that of the porous substrate layer is laminated on the porous substrate layer having a porous structure. Those having the above-mentioned structure are known. By providing this fine porous layer, it is said that the ultrafine porous structure of the fine porous layer inhibits the formation of a liquid water film and improves the drainage property of the gas diffusion layer.

このような微細多孔質層は、微細多孔質層形成用塗工液を多孔質基材層に塗布し、焼成することによって形成されるが、この塗布の際に微細多孔質層形成用塗工液が多孔質基材層中に浸透し、多孔質基材層を貫通する裏抜けという現象が発生することがある。この微細多孔質層形成用塗工液の多孔質基材層への浸み込み及び裏抜けが発生すると、ガス拡散層のガス拡散性の低下を招くおそれがある。 Such a fine porous layer is formed by applying a coating liquid for forming a fine porous layer to a porous base material layer and firing it. At the time of this coating, a coating for forming a fine porous layer is formed. A phenomenon called strike-through may occur in which the liquid permeates into the porous base material layer and penetrates through the porous base material layer. If the coating liquid for forming a fine porous layer penetrates into the porous base material layer and strike-through occurs, the gas diffusibility of the gas diffusion layer may decrease.

このような微細多孔質層形成用塗工液の裏抜けを防止するため、多くの技術が提案されている。特許文献１には、多孔質基材層と微細多孔質層とを有する燃料電池用ガス拡散層の製造方法であって、多孔質基材層の一方の面に微細多孔質層形成用塗工液を塗布するとともに、多孔質基材層の他方の面に撥水処理用の塗工液を塗布する工程を有する方法が提案されている。また、特許文献２には、多孔質基材層に撥水処理用の塗工液を塗布し、次いで微細多孔質層形成用塗工液を塗布する工程を備え、多孔質基材層を搬送するローラーの多孔質基材層との接触面が撥水性である、燃料電池用ガス拡散層の製造方法が提案されている。 Many techniques have been proposed in order to prevent strike-through of such a coating liquid for forming a fine porous layer. Patent Document 1 is a method for producing a gas diffusion layer for a fuel cell having a porous base material layer and a fine porous layer, wherein one surface of the porous base material layer is coated to form a fine porous layer. A method has been proposed in which the liquid is applied and a step of applying a coating liquid for water repellent treatment to the other surface of the porous base material layer is provided. Further, Patent Document 2 includes a step of applying a coating liquid for water-repellent treatment to a porous base material layer and then applying a coating liquid for forming a fine porous base material, and transports the porous base material layer. A method for producing a gas diffusion layer for a fuel cell has been proposed in which the contact surface of the roller with the porous base material layer is water repellent.

特開２０１５−０７６３７１号公報Japanese Unexamined Patent Publication No. 2015-076371 特開２０１５−０５００７３号公報Japanese Unexamined Patent Publication No. 2015-050073

特許文献１及び特許文献２に記載のガス拡散層の製造方法によれば、多孔質基材層に撥水処理用の塗工液を塗布することにより、あるいは多孔質基材層の搬送ローラーの表面を撥水性とすることにより、微細多孔質層形成用塗工液の多孔質基材層からの裏抜け量を低減することができるが、多孔質基材層内部への微細多孔質層形成用塗工液の浸み込みを十分に抑制することができない。その結果、このような従来の方法においては、多孔質基材層に微細多孔質層形成用塗工液を塗布する際に、微細多孔質層形成用塗工液が多孔質基材層内部に浸み込み、多孔質基材層内部のガス拡散性を阻害させることにより、得られるガス拡散層を組み込んだ燃料電池の発電性能を低下させるという問題がある。 According to the method for producing a gas diffusion layer described in Patent Document 1 and Patent Document 2, the porous base material layer is coated with a coating liquid for water repellent treatment, or the transfer roller of the porous base material layer is used. By making the surface water-repellent, the amount of strike-through of the coating liquid for forming a fine porous layer from the porous base material layer can be reduced, but the fine porous layer is formed inside the porous base material layer. It is not possible to sufficiently suppress the infiltration of the coating liquid. As a result, in such a conventional method, when the coating liquid for forming the fine porous layer is applied to the porous base material layer, the coating liquid for forming the fine porous layer is inside the porous base material layer. There is a problem that the power generation performance of the fuel cell incorporating the obtained gas diffusion layer is deteriorated by infiltrating and inhibiting the gas diffusivity inside the porous base material layer.

本発明は、上記実情を鑑みてなされたものであり、微細多孔質層形成用塗工液の多孔質基材層内部への浸み込みを抑制し、かつ多孔質基材層内部のガス拡散性の低下を抑制するガス拡散層を備えている燃料電池セル及びその製造方法を提供することを目的とする。 The present invention has been made in view of the above circumstances, and suppresses the infiltration of the coating liquid for forming a fine porous layer into the inside of the porous base material layer, and gas diffusion inside the porous base material layer. It is an object of the present invention to provide a fuel cell having a gas diffusion layer that suppresses deterioration of the property and a method for producing the same.

本発明は、以下の手段により上記目的を達成するものである。 The present invention achieves the above object by the following means.

<１>多孔質基材層と微細多孔質層とを備えた燃料電池用ガス拡散層と、セパレータとを備えている燃料電池セルの製造方法であって、以下の工程
（１）前記多孔質基材層の一方の面に、撥水処理用塗工液を塗布すること、
（２）前記撥水処理用塗工液を塗布した前記多孔質基材層を、加熱して乾燥させること、
（３）前記多孔質基材層の、前記撥水処理用塗工液を塗布した面とは反対の面に、微細多孔質層形成用塗工液を塗布すること、
（４）前記微細多孔質層形成用塗工液を塗布した前記多孔質基材層を、加熱して焼成すること、及び
（５）前記多孔質基材層の、前記微細多孔質層形成用塗工液を塗布した面とは反対の面に、凹凸形状を有するセパレータを配置すること
を含み、前記工程（１）において、凹凸形状を有する部材の凸部を、前記多孔質基材層の前記撥水処理用塗工液を塗布する面とは反対側の面と接触させた状態で、前記撥水処理用塗工液の塗布を行い、かつ
前記工程（５）において、前記多孔質基材の、前記凹凸形状を有する部材の凸部を接触させた箇所と対向する箇所に前記セパレータの凸部が接触するように前記セパレータを配置する、燃料電池セルの製造方法。 <1> A method for manufacturing a fuel cell, which includes a gas diffusion layer for a fuel cell having a porous base material layer and a fine porous layer, and a separator. The following steps (1) The porous material. Applying a water-repellent coating liquid to one surface of the base material layer,
(2) The porous base material layer coated with the water-repellent coating liquid is heated and dried.
(3) Applying the coating liquid for forming a fine porous layer to the surface of the porous base material layer opposite to the surface to which the coating liquid for water repellent treatment is applied.
(4) The porous base material layer coated with the coating liquid for forming the fine porous base material is heated and fired, and (5) for forming the fine porous base material of the porous base material layer. Including arranging a separator having an uneven shape on a surface opposite to the surface on which the coating liquid is applied, in the step (1), the convex portion of the member having an uneven shape is formed on the porous base material layer. The water-repellent coating liquid is applied in a state of being in contact with the surface opposite to the surface on which the water-repellent coating liquid is applied, and the porous group is applied in the step (5). A method for manufacturing a fuel cell, wherein the separator is arranged so that the convex portion of the separator comes into contact with a portion of the material that is in contact with the convex portion of the member having the uneven shape.

<２>前記工程（１）において使用する凹凸形状を有する部材が、第１の領域と第２の領域において凹凸の位相が半周期分ずれており、第１の領域が、前記多孔質基材層の面内において、前記セパレータのエア導入部の端部から、エア導入部の端部とエア出口部の端部の間の中間部までの範囲の領域であり、第２の領域が、エア導入部の端部とエア出口部の端部の間の中間部から、エア出口部の端部までの範囲の領域であり、
前記工程（５）において、前記工程（１）において前記多孔質基材層の第２の領域において前記凹凸形状を有する部材の凸部と接触した箇所と対向する箇所に前記セパレータの凸部が接触するように前記セパレータを配置する、
<１>記載の燃料電池セルの製造方法。 <2> The member having the concavo-convex shape used in the step (1) has the concavo-convex phase shifted by half a cycle in the first region and the second region, and the first region is the porous base material. In the plane of the layer, a region ranges from the end of the air introduction portion of the separator to the intermediate portion between the end portion of the air introduction portion and the end portion of the air outlet portion, and the second region is the air. The area from the middle part between the end of the introduction part and the end of the air outlet part to the end part of the air outlet part.
In the step (5), the convex portion of the separator comes into contact with a portion of the second region of the porous base material layer that is in contact with the convex portion of the member having the uneven shape in the step (1). The separator is arranged so as to
The method for manufacturing a fuel cell according to <1>.

<３>多孔質基材層と微細多孔質層とを備えた燃料電池用ガス拡散層と、セパレータとを備えている燃料電池セルであって、前記多孔質基材層の厚み方向における微細多孔質層の厚みが、前記セパレータの凸部が前記多孔質基材層と接触する箇所近傍において、その他の箇所よりも小さい、燃料電池セル。 <3> A fuel cell cell provided with a gas diffusion layer for a fuel cell having a porous base material layer and a fine porous layer and a separator, which is finely porous in the thickness direction of the porous base material layer. A fuel cell in which the thickness of the quality layer is smaller in the vicinity of a portion where the convex portion of the separator comes into contact with the porous base material layer than in other portions.

<４>前記燃料電池セルが第１の領域と第２の領域を有し、
第１の領域が、前記多孔質基材層の面内において、前記セパレータのエア導入部の端部から、エア導入部の端部とエア出口部の端部の間の中間部までの範囲の領域であり、第２の領域が、エア導入部の端部とエア出口部の端部の間の中間部から、エア出口部の端部までの範囲の領域であり、
第１の領域において、前記多孔質基材層の厚み方向における微細多孔質層の厚みが、前記セパレータの凸部が前記多孔質基材層と接触する箇所近傍において、その他の箇所よりも大きく、第２の領域において、前記多孔質基材層の厚み方向における微細多孔質層の厚みが、前記セパレータの凸部が前記多孔質基材層と接触する箇所近傍において、その他の箇所より小さい、<３>に記載の燃料電池セル。 <4> The fuel cell has a first region and a second region.
The first region ranges from the end of the air introduction portion of the separator to the intermediate portion between the end portion of the air introduction portion and the end portion of the air outlet portion in the plane of the porous base material layer. It is a region, and the second region is a region in the range from the intermediate portion between the end portion of the air introduction portion and the end portion of the air outlet portion to the end portion of the air outlet portion.
In the first region, the thickness of the microporous layer in the thickness direction of the porous base material layer is larger in the vicinity of the portion where the convex portion of the separator comes into contact with the porous substrate layer than in the other portions. In the second region, the thickness of the fine porous layer in the thickness direction of the porous substrate layer is smaller than the other locations in the vicinity of the portion where the convex portion of the separator contacts the porous substrate layer. The fuel cell according to 3>.

本発明の燃料電池セルの製造方法によれば、微細多孔質層形成用塗工液の多孔質基材層内部への浸み込みを抑制し、多孔質基材層内部のガス拡散性の低下を抑制することができる燃料電池セルを製造することができる。そして得られる燃料電池セルを用いて燃料電池を構成することにより、この燃料電池の発電性能の低下を抑制することができる。 According to the method for producing a fuel cell of the present invention, the coating liquid for forming a fine porous layer is suppressed from penetrating into the porous substrate layer, and the gas diffusivity inside the porous substrate layer is lowered. It is possible to manufacture a fuel cell that can suppress the above. By configuring the fuel cell using the obtained fuel cell, it is possible to suppress the deterioration of the power generation performance of the fuel cell.

燃料電池セルの構成を示す断面図である。It is sectional drawing which shows the structure of a fuel cell. 本発明の燃料電池セルの部分断面図である。It is a partial sectional view of the fuel cell of this invention. 本発明の燃料電池セルの製造方法を示す説明図である。It is explanatory drawing which shows the manufacturing method of the fuel cell of this invention. 撥水処理用塗工液の塗布工程を示す説明図である。It is explanatory drawing which shows the coating process of the coating liquid for water repellent treatment. 撥水処理用塗工液の塗布後の撥水剤の移動を示す説明図である。It is explanatory drawing which shows the movement of the water repellent agent after application of the coating liquid for water repellent treatment. 従来の方法により製造されたガス拡散層を備えた燃料電池セル中の撥水剤の分布を示す説明図である。It is explanatory drawing which shows the distribution of the water repellent agent in the fuel cell which provided with the gas diffusion layer manufactured by the conventional method. 微細多孔質層形成用塗工液の塗布工程における撥水剤の分布を示す説明図である。It is explanatory drawing which shows the distribution of the water repellent agent in the coating process of the coating liquid for forming a fine porous layer. プレス工程を示す説明図である。It is explanatory drawing which shows the pressing process. 燃料電池セルにおけるガス流路を示す略図である。It is a schematic diagram which shows the gas flow path in a fuel cell. 燃料電池セルにおけるエア導入部からの距離に対する発電性能の関係を示すグラフである。It is a graph which shows the relationship of the power generation performance with respect to the distance from the air introduction part in a fuel cell. 燃料電池セルにおけるエア導入部からの距離に対する電解質膜の含水率の関係を示すグラフである。It is a graph which shows the relationship of the water content of an electrolyte membrane with respect to the distance from an air introduction part in a fuel cell. 凹凸の位相が半周期分ずれている部材の上面図である。It is a top view of the member which the phase of the unevenness is shifted by half a cycle. 凹凸の位相が半周期分ずれている部材の斜視図である。It is a perspective view of the member which the phase of the unevenness is shifted by half a cycle. 本発明の燃料電池セルの第１の領域の部分断面図である。It is a partial sectional view of the 1st region of the fuel cell of this invention.

本発明の燃料電池セルの製造方法は、
（１）多孔質基材層の一方の面に、撥水処理用塗工液を塗布すること、
（２）前記撥水処理用塗工液を塗布した前記多孔質基材層を、加熱して乾燥させること、
（３）前記多孔質基材層の、前記撥水処理用塗工液を塗布した面とは反対の面に、微細多孔質層形成用塗工液を塗布すること、
（４）前記微細多孔質層形成用塗工液を塗布した前記多孔質基材層を、加熱して焼成すること、及び
（５）前記多孔質基材層の、前記微細多孔質層形成用塗工液を塗布した面とは反対の面に、凹凸形状を有するセパレータを配置すること
を含み、前記工程（１）において、凹凸形状を有する部材の凸部を、前記多孔質基材層の前記撥水処理用塗工液を塗布する面とは反対側の面と接触させた状態で、前記撥水処理用塗工液の塗布を行い、かつ
前記工程（５）において、前記多孔質基材の、前記凹凸形状を有する部材の凸部を接触させた箇所と対向する箇所に前記セパレータの凸部が接触するように前記セパレータを配置する。 The method for manufacturing a fuel cell of the present invention is
(1) Applying a water-repellent coating liquid to one surface of the porous base material layer,
(2) The porous base material layer coated with the water-repellent coating liquid is heated and dried.
(3) Applying the coating liquid for forming a fine porous layer to the surface of the porous base material layer opposite to the surface to which the coating liquid for water repellent treatment is applied.
(4) The porous base material layer coated with the coating liquid for forming the fine porous base material is heated and fired, and (5) for forming the fine porous base material of the porous base material layer. Including the arrangement of the separator having an uneven shape on the surface opposite to the surface on which the coating liquid is applied, in the step (1), the convex portion of the member having the uneven shape is formed on the porous base material layer. The water-repellent coating liquid is applied in a state of being in contact with the surface opposite to the surface on which the water-repellent coating liquid is applied, and the porous group is applied in the step (5). The separator is arranged so that the convex portion of the separator comes into contact with the portion of the material facing the convex portion of the member having the uneven shape.

また本発明の燃料電池セルは、
多孔質基材層と微細多孔質層とを備えた燃料電池用ガス拡散層と、セパレータとを備えており、前記多孔質基材層の厚み方向における微細多孔質層の厚みが、前記セパレータの凸部が前記多孔質基材層と接触する箇所近傍において、その他の箇所よりも小さい。 Further, the fuel cell of the present invention is
A gas diffusion layer for a fuel cell having a porous base material layer and a fine porous layer and a separator are provided, and the thickness of the fine porous layer in the thickness direction of the porous base material layer is the thickness of the separator. In the vicinity of the portion where the convex portion contacts the porous base material layer, it is smaller than the other portions.

上記したように従来のガス拡散層の製造方法においては、微細多孔質層形成用塗工液の多孔質基材層からの裏抜け量を低減することができるが、多孔質基材層内部への微細多孔質層形成用塗工液の浸み込みを十分に抑制することができず、この多孔質基材層内部に過剰に浸み込んだ微細多孔質層形成用塗工液が、多孔質基材層内部のガス拡散性を阻害させることにより、得られるガス拡散層を組み込んだ燃料電池の発電性能を低下させてしまう。 As described above, in the conventional method for producing a gas diffusion layer, the amount of strike-through of the coating liquid for forming a fine porous layer from the porous substrate layer can be reduced, but the inside of the porous substrate layer can be reduced. It was not possible to sufficiently suppress the infiltration of the coating liquid for forming the fine porous layer, and the coating liquid for forming the fine porous layer that had excessively penetrated into the porous base material layer was porous. By inhibiting the gas diffusivity inside the quality substrate layer, the power generation performance of the fuel cell incorporating the obtained gas diffusing layer is deteriorated.

これに対して本発明の方法によると、凹凸形状を有する部材の凸部を、多孔質基材層の撥水処理用塗工液を塗布する面とは反対側の面と接触させた状態で、多孔質基材層の一方の面への撥水処理用塗工液の塗布を行っている。その結果、撥水処理用塗工液中の撥水剤が、多孔質基材層の所定の箇所に、具体的には、多孔質基材層のうちの、凹凸形状を有する部材の凸部と接触している箇所に対向する箇所周囲に偏在することになり、微細多孔質層形成用塗工液の塗布後に、この多孔質基材層中の、撥水剤が偏在している所定の箇所への微細多孔質層形成用塗工液の浸み込みを特に抑制することができ、多孔質基材層の厚み方向の微細多孔質層の厚みを小さくすることができる。得られたガス拡散層を燃料電池に組み込んだ際に、この多孔質基材層中の撥水剤が偏在する箇所、すなわち微細多孔質層の厚みが小さい箇所を、燃料電池内のセパレータの凸部と接する箇所に位置合わせすることにより、燃料電池における多孔質基材層内の、ガス拡散性の低下、特にガス流路間のガス拡散性の低下を抑制することができる。 On the other hand, according to the method of the present invention, the convex portion of the member having an uneven shape is in contact with the surface of the porous base material layer opposite to the surface to which the water-repellent coating liquid is applied. , A water-repellent coating liquid is applied to one surface of the porous base material layer. As a result, the water-repellent agent in the coating liquid for water-repellent treatment is applied to a predetermined portion of the porous base material layer, specifically, a convex portion of a member having an uneven shape in the porous base material layer. The water repellent is unevenly distributed in the porous base material layer after the application of the coating liquid for forming the fine porous layer. The infiltration of the coating liquid for forming the fine porous layer into the portion can be particularly suppressed, and the thickness of the fine porous layer in the thickness direction of the porous base material layer can be reduced. When the obtained gas diffusion layer is incorporated into the fuel cell, the portion where the water repellent is unevenly distributed in the porous base material layer, that is, the portion where the thickness of the fine porous layer is small, is the convexity of the separator in the fuel cell. By aligning the position in contact with the portion, it is possible to suppress a decrease in gas diffusivity in the porous base material layer in the fuel cell, particularly a decrease in gas diffusivity between gas flow paths.

以下、本発明の実施形態について詳細に説明する。なお、本発明は、以下の実施形態に限定されるものではなく、本発明の要旨の範囲内で種々変形して実施することができる。 Hereinafter, embodiments of the present invention will be described in detail. The present invention is not limited to the following embodiments, and can be variously modified and implemented within the scope of the gist of the present invention.

<燃料電池の構成>
図１は、本発明の実施形態としての製造方法によって製造された燃料電池セルの概略構成を示す説明図である。図１において、燃料電池セル１０は、膜電極接合体３と２つのガス拡散層６と、一対のセパレータ７とを備えている。膜電極接合体３は、電解質膜１と、電解質膜１の両面に設けられた２つの触媒電極層２とを備えている。電解質膜１は、湿潤状態において良好なプロトン伝導性を示す固体高分子薄膜である。電解質膜１は、例えば、ナフィオン（登録商標）などのフッ素系樹脂のイオン交換膜によって構成される。触媒電極層２のそれぞれは、水素と酸素との化学反応を促進する触媒（図示は省略）を有する。触媒電極層２のそれぞれは、触媒を担持する導電性粒子（例えば、白金担持カーボン）と、電解質膜１と同種または類似の固体電解質樹脂と、の分散溶液の乾燥塗膜として形成される。 <Fuel cell configuration>
FIG. 1 is an explanatory diagram showing a schematic configuration of a fuel cell manufactured by the manufacturing method according to the embodiment of the present invention. In FIG. 1, the fuel cell 10 includes a membrane electrode assembly 3, two gas diffusion layers 6, and a pair of separators 7. The membrane electrode assembly 3 includes an electrolyte membrane 1 and two catalyst electrode layers 2 provided on both sides of the electrolyte membrane 1. The electrolyte membrane 1 is a solid polymer thin film that exhibits good proton conductivity in a wet state. The electrolyte membrane 1 is composed of, for example, an ion exchange membrane of a fluorine-based resin such as Nafion (registered trademark). Each of the catalyst electrode layers 2 has a catalyst (not shown) that promotes a chemical reaction between hydrogen and oxygen. Each of the catalyst electrode layers 2 is formed as a dry coating film of a dispersion solution of conductive particles (for example, platinum-supported carbon) carrying a catalyst and a solid electrolyte resin of the same type or similar to the electrolyte membrane 1.

ガス拡散層６のそれぞれは、膜電極接合体３の両面に形成されている。ガス拡散層６のそれぞれは、微細多孔質層４と多孔性基材層５を備えており、微細多孔質層４は触媒電極層２と接しており、多孔性基材層５はセパレータ７と接している。単セル１０が積層方向に圧縮されることで、ガス拡散層６のそれぞれは、各触媒電極層２に圧着されて膜電極接合体３と一体化している。 Each of the gas diffusion layers 6 is formed on both sides of the membrane electrode assembly 3. Each of the gas diffusion layers 6 includes a fine porous layer 4 and a porous base material layer 5, the fine porous layer 4 is in contact with the catalyst electrode layer 2, and the porous base material layer 5 is a separator 7. I'm in contact. By compressing the single cell 10 in the stacking direction, each of the gas diffusion layers 6 is pressure-bonded to each catalyst electrode layer 2 and integrated with the membrane electrode assembly 3.

ガス拡散層６のそれぞれは、セパレータ７に形成されているガス流路溝８を介して供給された反応ガスを触媒電極層２の全体に行き渡らせる。また、ガス拡散層６のそれぞれは、膜電極接合体３とセパレータ７との間の導電経路として機能する。燃料電池の運転中には、ガス拡散層６に供給された反応ガスは、ガス拡散層６の内部の貫通細孔内を流通し、ガス拡散層６の積層方向に直交する面方向に沿って拡散されながら、触媒電極層２に到達する。 Each of the gas diffusion layers 6 distributes the reaction gas supplied through the gas flow path groove 8 formed in the separator 7 to the entire catalyst electrode layer 2. Further, each of the gas diffusion layers 6 functions as a conductive path between the membrane electrode assembly 3 and the separator 7. During the operation of the fuel cell, the reaction gas supplied to the gas diffusion layer 6 flows through the through pores inside the gas diffusion layer 6 along the plane direction orthogonal to the stacking direction of the gas diffusion layer 6. It reaches the catalyst electrode layer 2 while being diffused.

膜電極接合体３の触媒電極層２と接する面に設けられた微細多孔質層４は、極微細な多孔質構造が液水膜の形成を阻害することにより、反応ガスの化学反応によって生成された水が反応ガスの流路を閉塞してしまうことを抑制し、その結果、膜電極接合体３と接する面におけるガス拡散性および排水性を確保する。セパレータと接する面に設けられた多孔性基材層５は、導電性多孔体から構成され、前記ガス流路溝８を通じて供給された反応ガスを分散させ、触媒層２に対して均一に供給し、触媒層２における酸化反応により生じた生成水を単セル外部に排出する役割を有する。 The microporous layer 4 provided on the surface of the membrane electrode assembly 3 in contact with the catalyst electrode layer 2 is generated by a chemical reaction of the reaction gas because the ultrafine porous structure inhibits the formation of a liquid-water film. It is possible to prevent the generated water from blocking the flow path of the reaction gas, and as a result, secure gas diffusibility and drainage property on the surface in contact with the membrane electrode assembly 3. The porous base material layer 5 provided on the surface in contact with the separator is composed of a conductive porous body, disperses the reaction gas supplied through the gas flow path groove 8, and uniformly supplies the reaction gas to the catalyst layer 2. It has a role of discharging the generated water generated by the oxidation reaction in the catalyst layer 2 to the outside of the single cell.

一対のセパレータ７は、導電性およびガス不透過性を有する板状部材であり、例えば、金属板によって構成される。セパレータ７のそれぞれは、ガス拡散層６のそれぞれの表面に積層して配置されている。セパレータ７のそれぞれには、反応ガスの水素または酸素が流れるガス流路溝８が形成されている。 The pair of separators 7 are plate-like members having conductivity and gas impermeableness, and are composed of, for example, a metal plate. Each of the separators 7 is laminated and arranged on the respective surfaces of the gas diffusion layer 6. Each of the separators 7 is formed with a gas flow path groove 8 through which hydrogen or oxygen as a reaction gas flows.

図示及び詳細な説明は省略するが、各単セル１０の膜電極接合体３及びガス拡散層６の外側に、反応ガス等の流体の漏洩やセパレータ７同士の短絡を防止するための絶縁性シール部が設けられる。また、単セル１０の膜電極接合体３及びガス拡散層６の外側には、単セル１０に反応ガスを供給するためのマニホールドが設けられる。 Although illustration and detailed description are omitted, an insulating seal for preventing fluid leakage such as reaction gas and short circuit between separators 7 is provided on the outside of the membrane electrode assembly 3 and the gas diffusion layer 6 of each single cell 10. A part is provided. Further, a manifold for supplying the reaction gas to the single cell 10 is provided on the outside of the membrane electrode assembly 3 and the gas diffusion layer 6 of the single cell 10.

図２に、本発明の燃料電池セルの部分断面図を示す。本発明の燃料電池セルのガス拡散層６においては、多孔質基材層５内には撥水剤２３が偏在し、また微細多孔質層４が浸透している。この撥水剤２３が偏在してより多く存在する箇所１４は、燃料電池セルにおいてセパレータ７のガス流路溝８間のリブ９と接する箇所に対向する箇所に相当する。この箇所に撥水剤２３を多く偏在していることにより、図２に示すように、前記多孔質基材層５の厚み方向における微細多孔質層４の厚みが、前記セパレータ７の凸部９が前記多孔質基材５層と接触する箇所近傍において、その他の箇所よりも小さくなっており、矢印に示すような、多孔質基材層５を通過してセパレータ７のガス流路溝８間を移動するガスの移動が妨げられることがなく、ガス透過性の低下を抑制することができる。 FIG. 2 shows a partial cross-sectional view of the fuel cell of the present invention. In the gas diffusion layer 6 of the fuel cell of the present invention, the water repellent 23 is unevenly distributed in the porous base material layer 5, and the fine porous layer 4 permeates. The portion 14 in which the water repellent 23 is unevenly distributed and more present corresponds to a portion facing the portion in contact with the rib 9 between the gas flow path grooves 8 of the separator 7 in the fuel cell. Since a large amount of the water repellent 23 is unevenly distributed in this portion, as shown in FIG. 2, the thickness of the fine porous layer 4 in the thickness direction of the porous base material layer 5 is reduced to the convex portion 9 of the separator 7. Is smaller than the other parts in the vicinity of the part in contact with the 5 layers of the porous base material, and passes through the porous base material layer 5 and between the gas flow path grooves 8 of the separator 7 as shown by the arrow. The movement of the gas moving in the gas is not hindered, and the decrease in gas permeability can be suppressed.

<燃料電池セルの製造方法>
本発明の燃料電池セルの製造方法は、例えば、図３に示すように、第１の塗工装置２０と、第１の加熱装置３０と、第２の塗工装置４０と、第２の加熱装置５０と、を備える製造装置１００により実行される。この製造装置１００では、ガス拡散層の多孔質基材層の形成に用いられる長尺シート状の多孔質基材層１１が、搬送ローラー１２によって搬送されて、第１の塗工装置２０、第１の加熱装置３０、第２の塗工装置４０、第２の加熱装置５０へ順に送り込まれることにより、各装置に対応する撥水処理用塗工液塗布工程（工程１）、乾燥工程（工程２）、微細多孔質層形成用塗工液塗布工程（工程３）、焼成工程（工程４）が順に実行される。従って、第１の塗工装置２０、第１の加熱装置３０、第２の塗工装置４０、及び第２の加熱装置５０は、基材１１が搬送される搬送路中に順に配置されている。以下、本発明のガス拡散層の製造方法の各工程について説明する。 <Manufacturing method of fuel cell>
The method for manufacturing a fuel cell of the present invention is, for example, as shown in FIG. 3, a first coating device 20, a first heating device 30, a second coating device 40, and a second heating. It is executed by the manufacturing apparatus 100 including the apparatus 50. In this manufacturing apparatus 100, the long sheet-like porous substrate layer 11 used for forming the porous substrate layer of the gas diffusion layer is conveyed by the conveying roller 12, and the first coating apparatus 20, the first coating apparatus 100, The water-repellent coating liquid coating step (step 1) and the drying step (step 1) corresponding to each device are sent in order to the heating device 30, the second coating device 40, and the second heating device 50. 2), the coating liquid coating step for forming a fine porous layer (step 3), and the firing step (step 4) are executed in this order. Therefore, the first coating device 20, the first heating device 30, the second coating device 40, and the second heating device 50 are sequentially arranged in the transport path in which the base material 11 is conveyed. .. Hereinafter, each step of the method for producing the gas diffusion layer of the present invention will be described.

<撥水処理用塗工液塗布工程（工程１）>
撥水処理用塗工液塗布工程では、多孔質基材層の一方の面に、撥水処理用塗工液を塗布する。そして、凹凸形状を有する部材の凸部を、多孔質基材層の撥水処理用塗工液を塗布する面とは反対側の面と接触させた状態で、この撥水処理用塗工液の塗布を行う。 <Water repellent coating liquid application process (process 1)>
In the water-repellent treatment coating liquid application step, the water-repellent treatment coating liquid is applied to one surface of the porous base material layer. Then, in a state where the convex portion of the member having the uneven shape is in contact with the surface of the porous base material layer opposite to the surface to which the water repellent treatment coating liquid is applied, the water repellent treatment coating liquid is brought into contact with the surface. Is applied.

例えば図３に示すように、撥水処理用塗工液塗布工程に対応する第１の塗工装置２０は、ダイ方式のコーターにより構成されていてよい。第１の塗工装置２０は、ダイヘッド２１を備えていてよい。ダイヘッド２１には、撥水処理用塗工液が充填されていてよい。撥水処理用塗工液塗布工程では、多孔質基材層１１の一方の面に、ダイヘッド２１によって、撥水処理用塗工液が塗布される。塗工目付は、例えば０．１〜１ｍｇ／ｃｍ2である。 For example, as shown in FIG. 3, the first coating device 20 corresponding to the coating liquid coating step for water repellent treatment may be composed of a die-type coater. The first coating device 20 may include a die head 21. The die head 21 may be filled with a water-repellent coating liquid. In the water-repellent treatment coating liquid application step, the water-repellent treatment coating liquid is applied to one surface of the porous base material layer 11 by the die head 21. The coating basis weight is, for example, 0.1 to 1 mg / cm 2 .

塗布された撥水処理用塗工液は、その塗布面から多孔質基材層１１内へ浸透する。これにより、多孔質基材層１１の表面および内部に対して撥水剤を分布させて撥水性を付与する撥水処理を施すことが可能となる。 The applied water-repellent coating liquid permeates into the porous base material layer 11 from the coated surface. This makes it possible to apply a water-repellent treatment for imparting water repellency by distributing a water-repellent agent to the surface and the inside of the porous base material layer 11.

この撥水処理用塗工液塗布工程の詳細を図４に示す。上記のように、撥水処理用塗工液塗布工程において、多孔質基材層１１の一方の面にダイヘッド２１から撥水処理用塗工液２２が塗布される。ここで、多孔質基材層１１は搬送ベルト１３と接した状態で第１の塗工装置２０に搬送され、搬送ベルト１３は、単セルを構成するセパレータ７の形状を模した凹凸形状を有している（すなわち、凹凸形状を有する部材である）。そして、この搬送ベルト１３の凸部が、多孔質基材層の撥水処理用塗工液を塗布する面とは反対の面と接触している状態で、撥水処理用塗工液２２が塗布される。 The details of the coating liquid coating process for water repellent treatment are shown in FIG. As described above, in the water-repellent treatment coating liquid coating step, the water-repellent treatment coating liquid 22 is applied from the die head 21 to one surface of the porous base material layer 11. Here, the porous base material layer 11 is transported to the first coating device 20 in a state of being in contact with the transport belt 13, and the transport belt 13 has an uneven shape that imitates the shape of the separator 7 constituting the single cell. (That is, it is a member having an uneven shape). Then, in a state where the convex portion of the transport belt 13 is in contact with the surface of the porous base material layer opposite to the surface on which the water-repellent coating liquid is applied, the water-repellent coating liquid 22 is applied. It is applied.

この塗布された撥水処理用塗工液は、多孔質基材層内に浸透するが、図５に示すように、撥水処理用塗工液中の水は、多孔質基材層１１内を、多孔質基材層１１と搬送ベルト１３の凸部との接触部に向かって毛管力によって移動する。その際、撥水処理用塗工液２２中の撥水剤２３も移動し、多孔質基材層１１と搬送ベルト１３の凸部との接触部に多く偏在することになる。 The applied water-repellent coating liquid permeates into the porous base material layer, but as shown in FIG. 5, the water in the water-repellent treatment coating liquid penetrates into the porous base material layer 11. Is moved toward the contact portion between the porous base material layer 11 and the convex portion of the transport belt 13 by the capillary force. At that time, the water repellent 23 in the water repellent coating liquid 22 also moves, and is unevenly distributed in the contact portion between the porous base material layer 11 and the convex portion of the transport belt 13.

ここで、多孔質基材層１１としては、燃料電池のガス拡散層の基材に一般的に用いられている導電性および多孔質性を有するシート状材料、例えば、カーボンペーパーやカーボンクロス、カーボン不織布等のカーボン繊維による多孔性シート材料を用いることができる。 Here, the porous base material layer 11 is a sheet-like material having conductivity and porosity that is generally used as a base material of a gas diffusion layer of a fuel cell, for example, carbon paper, carbon cloth, or carbon. A porous sheet material made of carbon fiber such as a non-woven fabric can be used.

また、撥水処理用塗工液は、撥水剤の分散液である。撥水剤としては、ＰＴＦＥ、ＰＶＤＦ、ポリヘキサフルオロプロピレン、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等のフッ素系の高分子材料や、ポリプロピレン、ポリエチレン等が利用可能である。そして、これらの材料のうち、フッ素系の高分子材料、特に、ＰＴＦＥが好ましく用いられる。例えば、撥水剤としてＰＴＦＥを用い、ＰＴＦＥ（粒径：１００〜４００ｎｍ）のディスパージョンを希釈する（濃度：３〜５質量％）ことにより、撥水処理用塗工液の粘度がずり速度５０ｓ-1において１〜１００ｍＰａ・ｓとなるように調整することができる。 The coating liquid for water repellent treatment is a dispersion liquid of a water repellent agent. As the water repellent, a fluorine-based polymer material such as PTFE, PVDF, polyhexafluoropropylene, or tetrafluoroethylene-hexafluoropropylene copolymer, polypropylene, polyethylene or the like can be used. Among these materials, a fluorine-based polymer material, particularly PTFE, is preferably used. For example, by using PTFE as a water repellent and diluting the dispersion of PTFE (particle size: 100 to 400 nm) (concentration: 3 to 5% by mass), the viscosity of the water repellent coating liquid becomes a shear rate of 50 s. It can be adjusted to be 1 to 100 mPa · s at -1 .

<乾燥工程（工程２）>
乾燥工程では、撥水処理用塗工液を塗布した多孔質基材層を、加熱して乾燥させる。 <Drying process (process 2)>
In the drying step, the porous base material layer coated with the water-repellent coating liquid is heated and dried.

再び図３を参照して示すように、乾燥工程に対応する第１の加熱装置３０は、一般的な加熱炉により構成してよい。乾燥工程では、撥水処理用塗工液２２の塗工済み多孔質基材層１１が、第１の塗工装置２０から順に送り込まれて装置内を順に移動し、外部へ送り出されるまでの間に、塗工済み多孔質基材層１１をヒーター３１により加熱することにより、撥水処理用塗工液２２の乾燥が行われる。これにより、撥水処理用塗工液２２に含まれる撥水剤２３によって多孔質基材層１１に撥水性が付与される。 As shown again with reference to FIG. 3, the first heating device 30 corresponding to the drying step may be configured by a general heating furnace. In the drying step, the coated porous base material layer 11 of the water-repellent coating liquid 22 is sequentially fed from the first coating device 20 and moves in the device in order until it is sent out to the outside. In addition, the water-repellent coating liquid 22 is dried by heating the coated porous base material layer 11 with the heater 31. As a result, the water-repellent agent 23 contained in the water-repellent coating liquid 22 imparts water repellency to the porous base material layer 11.

第１の加熱装置３０における乾燥のための加熱時間（乾燥時間）は、第１の加熱装置３０に送り込まれた塗工済み多孔質基材層１１が、外部へ送り出されるまでの時間に相当する。この時間は、塗工済み多孔質基材層１１が加熱装置３０内を移動する速度および移動する長さで決定される。なお、第１の加熱装置３０における加熱温度（乾燥温度）は、撥水処理用塗工液２２を乾燥させるための温度であり、好ましくは、この乾燥温度は５０℃〜９０℃である。また、加熱時間（乾燥時間）は、塗工液の塗布量および加熱温度等に応じて、適切な時間、例えば、１分〜１２０分程度の時間に設定される。なお、加熱時間の上限にも特に制限はない。 The heating time (drying time) for drying in the first heating device 30 corresponds to the time until the coated porous base material layer 11 sent to the first heating device 30 is sent out to the outside. .. This time is determined by the speed and length of movement of the coated porous substrate layer 11 in the heating device 30. The heating temperature (drying temperature) in the first heating device 30 is a temperature for drying the water-repellent coating liquid 22, and the drying temperature is preferably 50 ° C. to 90 ° C. The heating time (drying time) is set to an appropriate time, for example, about 1 minute to 120 minutes, depending on the coating amount of the coating liquid, the heating temperature, and the like. The upper limit of the heating time is not particularly limited.

<微細多孔質層形成用塗工液塗布工程（工程３）＞
微細多孔質層形成用塗工液塗布工程では、多孔質基材層の撥水処理用塗工液を塗布した面とは反対の面に、微細多孔質層形成用塗工液を塗布する。 <Coating liquid coating process for forming a fine porous layer (process 3)>
In the process of applying the coating liquid for forming the fine porous layer, the coating liquid for forming the fine porous layer is applied to the surface of the porous base material layer opposite to the surface to which the water-repellent coating liquid is applied.

図３に示すように、微細多孔質層形成用塗工液塗布工程に対応する第２の塗工装置４０は、例えばダイ方式のコーターにより構成されている。第２の塗工装置４０は、ダイヘッド４１を備えていてよい。ダイヘッド４１には、多孔質基材層１１の一方の面に微細多孔質層を形成するための、微細多孔質層形成用塗工液４２が充填されていてよい。なお、微細多孔質層は、多孔質基材層１１よりも小さな細孔径を有している。塗工目付は、例えば２〜６ｍｇ／ｃｍ2である。塗布された微細多孔質層形成用塗工液４２の塗膜の厚さは、多孔質基材層１１がダイヘッド４１の下を通過する速度及びダイヘッド４１から吐出される微細多孔質層形成用塗工液４２の吐出速度によって決定される。 As shown in FIG. 3, the second coating apparatus 40 corresponding to the coating liquid coating step for forming a fine porous layer is composed of, for example, a die-type coater. The second coating device 40 may include a die head 41. The die head 41 may be filled with a coating liquid 42 for forming a fine porous layer for forming a fine porous layer on one surface of the porous base material layer 11. The fine porous layer has a pore diameter smaller than that of the porous base material layer 11. The coating basis weight is, for example, 2 to 6 mg / cm 2 . The thickness of the coating film of the applied coating liquid 42 for forming a fine porous layer is the speed at which the porous base material layer 11 passes under the die head 41 and the coating for forming a fine porous layer discharged from the die head 41. It is determined by the discharge rate of the working liquid 42.

従来技術の方法のように、多孔質基材層１１の、微細多孔質層形成用塗工液４２を塗布する面とは反対面を撥水性とする場合、微細多孔質層形成用塗工液４２を多孔質基材層１１に塗布すると、図６に示すように、この微細多孔質層形成用塗工液４２には、（１）ダイヘッド４１からの吐出圧力、（２）多孔質基材層１１内部への毛管力、（３）微細多孔質層形成用塗工液４２の自重、の３つの力が作用し、多孔質基材層１１内部への物理的な空間内への過剰な浸み込みが発生する。 When the surface of the porous base material layer 11 opposite to the surface to which the fine porous layer forming coating liquid 42 is applied is made water-repellent as in the conventional method, the fine porous layer forming coating liquid is used. When 42 is applied to the porous base material layer 11, as shown in FIG. 6, the coating liquid 42 for forming the fine porous layer has (1) discharge pressure from the die head 41 and (2) porous base material. Three forces, the capillary force inside the layer 11 and (3) the weight of the coating liquid 42 for forming the fine porous layer 42, act to cause an excess in the physical space inside the porous substrate layer 11. Penetration occurs.

この微細多孔質層形成用塗工液４２の多孔質基材層１１内部への浸み込みは、多孔質基材層１１内部の空間の閉塞を引き起こし、ガス透過性の低下を引き起こす。特に、図６に示すように、多孔質基材層１１の、セパレータ７のリブ（凸部）９との接触箇所付近においては、矢印に示すような、多孔質基材層１１を通過してセパレータ７のガス流路溝８間を移動するガスの移動が妨げられるため、ガス透過性の低下は顕著になる。その結果、多孔質基材層１１の、セパレータ７のリブ９との接触箇所付近においてガス供給不足が引き起こされ、発電性能の低下につながる。 The infiltration of the coating liquid 42 for forming the fine porous layer into the inside of the porous base material layer 11 causes the space inside the porous base material layer 11 to be blocked, and causes a decrease in gas permeability. In particular, as shown in FIG. 6, in the vicinity of the contact portion of the porous base material layer 11 with the rib (convex portion) 9 of the separator 7, it passes through the porous base material layer 11 as shown by the arrow. Since the movement of the gas moving between the gas flow path grooves 8 of the separator 7 is hindered, the decrease in gas permeability becomes remarkable. As a result, the gas supply shortage is caused in the vicinity of the contact point of the separator 7 with the rib 9 of the porous base material layer 11, which leads to a decrease in power generation performance.

これに対して、本発明においては、図７に示すように、微細多孔質層形成用塗工液４２を塗布する際に、多孔質基材層１１内には、撥水処理用塗工液塗布工程によって浸透させた撥水剤２３が偏在している。この撥水剤２３が偏在してより多く存在する箇所１４は、撥水処理用塗工液塗布工程において、多孔質基材層１１中の搬送ベルト１３の凸部等の、凹凸形状を有する部材の凸部と接していた箇所に対応している。この凹凸形状は、単セルを構成するセパレータ７の形状を模しており、従ってこの撥水剤２３が多く偏在する箇所１４は、燃料電池セルにおいてセパレータ７のガス流路溝８間のリブ（凸部）９と接する箇所に相当することになる。この箇所に撥水剤２３を多く偏在させることにより、図７に示すように、微細多孔質層形成用塗工液４２を塗布した際、この微細多孔質層形成用塗工液４２は多孔質基材層１１の内部にも浸透するが、撥水剤２３が多く偏在している箇所１４へは、撥水剤２３によって、の微細多孔質層形成用塗工液４２の浸み込みが抑制される。その結果、図２中の矢印に示すような、多孔質基材層１１を通過してセパレータ７のガス流路溝８間を移動するガスの移動が妨げられることがなく、ガス透過性の低下を抑制することができる。 On the other hand, in the present invention, as shown in FIG. 7, when the coating liquid 42 for forming a fine porous layer is applied, the coating liquid for water repellent treatment is inside the porous base material layer 11. The water repellent 23 permeated by the coating process is unevenly distributed. The portion 14 where the water repellent 23 is unevenly distributed and more present is a member having an uneven shape such as a convex portion of the transport belt 13 in the porous base material layer 11 in the water repellent treatment coating liquid application step. Corresponds to the part that was in contact with the convex part of. This uneven shape imitates the shape of the separator 7 constituting the single cell, and therefore, the portion 14 in which the water repellent 23 is unevenly distributed is a rib between the gas flow path grooves 8 of the separator 7 in the fuel cell. Convex portion) Corresponds to the portion in contact with 9. By unevenly distributing a large amount of the water repellent 23 in this portion, as shown in FIG. 7, when the coating liquid 42 for forming a fine porous layer is applied, the coating liquid 42 for forming a fine porous layer is porous. Although it penetrates into the base material layer 11, the water repellent 23 suppresses the infiltration of the coating liquid 42 for forming the fine porous layer into the portion 14 where the water repellent 23 is unevenly distributed. Will be done. As a result, as shown by the arrow in FIG. 2, the movement of the gas passing through the porous base material layer 11 and moving between the gas flow path grooves 8 of the separator 7 is not hindered, and the gas permeability is lowered. Can be suppressed.

ここで、微細多孔質層形成用塗工液４２は、主に導電性粒子とバインダーと溶剤とを混合分散させたペースト状あるいはスラリー状のものであってよい。微細多孔質層形成用塗工液４２には、必要に応じて分散剤等の添加剤を加えることができるが、コンタミネーションを回避するために金属を含まないことが好ましい。 Here, the coating liquid 42 for forming a fine porous layer may be in the form of a paste or a slurry in which conductive particles, a binder and a solvent are mainly mixed and dispersed. Additives such as a dispersant can be added to the coating liquid 42 for forming a fine porous layer, if necessary, but it is preferable that the coating liquid 42 does not contain a metal in order to avoid contamination.

導電性粒子としては、カーボン粒子、特に平均粒径が２０〜１５０ｎｍのカーボン粒子、例えば、導電性に優れ、比表面積が大きいカーボンブラックを用いることができ、特に、導電性が高いアセチレンブラックが好ましい。バインダーとしては、ポリテトラフルオロエチレン（ＰＴＦＥ）、ポリフッ化ビニリデン（ＰＶＤＦ）、ポリヘキサフルオロプロピレン、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等のフッ素系の高分子材料や、ポリプロピレン、ポリエチレン等を用いることができる。そして、これらの材料のうち、フッ素系の高分子材料、特に、ＰＴＦＥが好ましく用いられる。溶剤としては、特に制限されず、水、メタノール、エタノール等の種々の液剤を用いることができる。分散剤である界面活性剤も、特に制限されず、エステル型やエーテル型、エステル・エーテル型等の種々の非イオン系界面活性剤等の種々の界面活性剤を用いることができる。 As the conductive particles, carbon particles, particularly carbon particles having an average particle diameter of 20 to 150 nm, for example, carbon black having excellent conductivity and a large specific surface area can be used, and acetylene black having high conductivity is particularly preferable. .. As the binder, fluorine-based polymer materials such as polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polyhexafluoropropylene, and tetrafluoroethylene-hexafluoropropylene copolymer, polypropylene, polyethylene, and the like are used. be able to. Among these materials, a fluorine-based polymer material, particularly PTFE, is preferably used. The solvent is not particularly limited, and various liquid agents such as water, methanol, and ethanol can be used. The surfactant as a dispersant is also not particularly limited, and various surfactants such as various nonionic surfactants such as ester type, ether type and ester ether type can be used.

微細多孔質層形成用塗工液４２の組成は、例えば、導電性粒子とバインダーと分散剤の全固形分を１００質量％として、導電性粒子が７０〜９０質量％、バインダーが１５〜２５質量％、分散剤が５〜１５質量％となるように調整する。また、微細多孔質層形成用塗工液４２の物性は、固形分の割合が１５〜２５質量％で、粘度がずり速度５０ｓ-1において５００〜２５００ｍＰａ・ｓ（５０／ｓ）で、貯蔵弾性率が５００〜５５００Ｐａとなるように設定してよい。 The composition of the coating liquid 42 for forming the fine porous layer is, for example, 70 to 90% by mass of the conductive particles and 15 to 25% by mass of the binder, where the total solid content of the conductive particles, the binder and the dispersant is 100% by mass. %, The dispersant is adjusted to 5 to 15% by mass. The physical properties of the coating liquid 42 for forming a fine porous layer are as follows: a solid content ratio of 15 to 25% by mass, a viscosity of 500 to 2500 mPa · s (50 / s) at a shear rate of 50 s -1 , and storage elasticity. The rate may be set to be 500 to 5500 Pa.

微細多孔質層形成用塗工液４２が塗布済みの多孔質基材層１１は、第２の加熱装置５０に搬送される。 The porous base material layer 11 to which the coating liquid 42 for forming the fine porous layer has been applied is conveyed to the second heating device 50.

<焼成工程（工程４）>
焼成工程では、微細多孔質層形成用塗工液を塗布した多孔質基材層を加熱して焼成する。 <Baking step (step 4)>
In the firing step, the porous base material layer coated with the coating liquid for forming a fine porous layer is heated and fired.

再び図３を参照して示すように、焼成工程に対応する第２の加熱装置５０は、一般的な加熱炉により構成してよい。焼成工程では、微細多孔質層形成用塗工液４２の塗工済み多孔性基材層１１が、第２の塗工装置４０から順に送り込まれて装置内を順に移動し、外部へ送り出されるまでの間に、塗工済み基材１１をヒーター５１により加熱することにより、微細多孔質層形成用塗工液４２による塗膜の焼成処理を実行する。これにより、微細多孔質層形成用塗工液４２の塗膜が微細多孔質層として多孔性基材層１１上に定着され、多孔性基材層と微細多孔質層とが積層された長尺シート状のガス拡散層が形成される。 As shown again with reference to FIG. 3, the second heating device 50 corresponding to the firing step may be configured by a general heating furnace. In the firing step, the coated porous base material layer 11 of the coating liquid 42 for forming a fine porous layer is sequentially fed from the second coating apparatus 40, moves in order in the apparatus, and is sent out to the outside. By heating the coated base material 11 with the heater 51, the coating film is fired with the coating liquid 42 for forming the fine porous layer. As a result, the coating film of the coating liquid 42 for forming the fine porous layer is fixed on the porous base material layer 11 as a fine porous layer, and the porous base material layer and the fine porous layer are laminated. A sheet-like gas diffusion layer is formed.

加熱装置５０における焼成のための加熱時間（焼成時間）は、焼成装置５０に送り込まれた塗工済み多孔性基材層１１が、外部へ送り出されるまでの時間に相当する。この時間は、塗工済み多孔性基材層１１が加熱装置５０内を移動する速度および移動する長さで決定される。なお、加熱装置５０における加熱温度（焼成温度）は、微細多孔質層形成用塗工液４２中の導電性粒子とバインダーとを熱融着するための温度であり、好ましくは２５０℃以上、より好ましくは４００℃以上の温度に設定される。なお、加熱温度の上限に特に制限はない。また、加熱時間（焼成時間）は、微細多孔質層形成用塗工液の塗工量および加熱温度等に応じて、適切な時間、例えば、１分〜１２０分程度の時間に設定される。なお、加熱時間の上限にも特に制限はない。 The heating time (firing time) for firing in the heating device 50 corresponds to the time until the coated porous base material layer 11 sent to the firing device 50 is sent out to the outside. This time is determined by the speed and length of movement of the coated porous substrate layer 11 in the heating device 50. The heating temperature (firing temperature) in the heating device 50 is a temperature for heat-sealing the conductive particles and the binder in the coating liquid 42 for forming a fine porous layer, preferably 250 ° C. or higher. The temperature is preferably set to 400 ° C. or higher. The upper limit of the heating temperature is not particularly limited. The heating time (baking time) is set to an appropriate time, for example, about 1 minute to 120 minutes, depending on the coating amount of the coating liquid for forming the fine porous layer, the heating temperature, and the like. The upper limit of the heating time is not particularly limited.

焼成工程において製造された、多孔性基材層と微細多孔質層とが積層された長尺シート状のガス拡散層は、図示しない一般的な裁断機により、所望の形状に裁断することにより、所望形状のガス拡散層が形成される。 The long sheet-like gas diffusion layer in which the porous base material layer and the fine porous layer are laminated, which is produced in the firing step, is cut into a desired shape by a general cutting machine (not shown). A gas diffusion layer having a desired shape is formed.

<セパレータ配置工程（工程５）>
セパレータ配置工程では、工程４において得られたガス拡散層にセパレータを配置する。 <Separator placement process (process 5)>
In the separator placement step, the separator is placed on the gas diffusion layer obtained in step 4.

図２に示すように、セパレータ７は、導電性およびガス不透過性を有する板状部材であり、例えば、金属板によって構成される。セパレータ７はその断面において凹凸形状を有しており、凹部は反応ガスの水素または酸素が流れるガス流路溝８に対応し、凸部は多孔質基材層５と接するリブ９に対応する。そしてセパレータ７は、多孔質基材５の、凹凸形状を有する部材の凸部を接触させた箇所１４と対向する箇所にセパレータの凸部９が接触するように配置されている。 As shown in FIG. 2, the separator 7 is a plate-like member having conductivity and gas impermeableness, and is composed of, for example, a metal plate. The separator 7 has an uneven shape in its cross section, the concave portion corresponds to the gas flow path groove 8 through which hydrogen or oxygen of the reaction gas flows, and the convex portion corresponds to the rib 9 in contact with the porous base material layer 5. The separator 7 is arranged so that the convex portion 9 of the separator comes into contact with the portion 14 of the porous base material 5 that is in contact with the convex portion of the member having an uneven shape.

このようにセパレータ７を配置することにより、多孔質基材層５の厚み方向における微細多孔質層４の厚みが、セパレータ７の凸部９が多孔質基材５層と接触する箇所近傍において、その他の箇所よりも小さくなっているため、矢印に示すような、多孔質基材層５を通過してセパレータ７のガス流路溝８間を移動するガスの移動が妨げられることがなく、ガス透過性の低下を抑制することができる。 By arranging the separator 7 in this way, the thickness of the microporous layer 4 in the thickness direction of the porous base material layer 5 is increased in the vicinity of the portion where the convex portion 9 of the separator 7 comes into contact with the porous base material 5 layer. Since it is smaller than the other parts, the movement of the gas that passes through the porous base material layer 5 and moves between the gas flow path grooves 8 of the separator 7 as shown by the arrow is not hindered, and the gas is not hindered. It is possible to suppress a decrease in permeability.

本発明においては、乾燥工程の後、微細多孔質層形成用塗工液塗布工程の前に、プレス装置６０においてプレス工程を行うことが好ましい。このプレス工程においては、例えば図８に示すように、乾燥工程の乾燥装置３０において乾燥された多孔性基材層１１が、搬送ベルト１３と接した状態でプレス装置６０に送り込まれ、所定の位置において２枚のプレス板６１によりプレスされる。この際、搬送ベルト１３には、所定の位置に位置決め用の突起１５が設けられており、プレスによって多孔性基材層の所定の位置に凹部を形成することができる。 In the present invention, it is preferable to perform the pressing step in the pressing apparatus 60 after the drying step and before the coating liquid coating step for forming the fine porous layer. In this pressing step, for example, as shown in FIG. 8, the porous base material layer 11 dried in the drying device 30 in the drying step is sent to the pressing device 60 in contact with the transport belt 13 and at a predetermined position. Is pressed by two press plates 61. At this time, the transport belt 13 is provided with a protrusion 15 for positioning at a predetermined position, and a recess can be formed at a predetermined position on the porous base material layer by pressing.

上記のように、撥水処理用塗工液塗布工程において、多孔性基材層１１は搬送ベルト１３と接した状態で撥水処理用塗工液が塗布され、その結果、多孔性基材層１１の、搬送ベルト１３の凸部との接触部に撥水剤２３が多く偏在することになる。この搬送ベルト１３の凹凸形状は、セパレータのガス流路溝８を構成する凹凸形状を模したものであり、多孔性基材層１１の、搬送ベルト１３の凸部との接触部、すなわち撥水剤が多く偏在している箇所１４に対向する箇所に、セパレータのガス流路溝８を構成するリブの凸部９を配置させるようにすることが必要である。 As described above, in the water repellent treatment coating liquid application step, the water repellent treatment coating liquid is applied to the porous base material layer 11 in contact with the transport belt 13, and as a result, the porous base material layer is applied. A large amount of the water repellent 23 is unevenly distributed in the contact portion of the transport belt 13 with the convex portion of the transport belt 13. The uneven shape of the transport belt 13 imitates the uneven shape constituting the gas flow path groove 8 of the separator, and the contact portion of the porous base material layer 11 with the convex portion of the transport belt 13, that is, water repellency. It is necessary to arrange the convex portion 9 of the rib forming the gas flow path groove 8 of the separator at a portion facing the portion 14 where a large amount of the agent is unevenly distributed.

上記のように、プレス工程において多孔性基材層の所定の位置に凹部を形成することにより、その後に燃料電池セルを構成する段階において、この凹部を目印にして、セパレータとの正確な位置決めが可能となる。 As described above, by forming a recess at a predetermined position on the porous base material layer in the pressing process, accurate positioning with the separator can be performed by using this recess as a mark in the subsequent stage of forming the fuel cell. It will be possible.

ところで、燃料電池セルにおいては、図９に示すように、一方のマニホールド９１に燃料剤ガスもしくは酸化剤ガスが導入され、このガスはガス流路８を通過し、マニホールド９２から排出される。 By the way, in the fuel cell, as shown in FIG. 9, a fuel agent gas or an oxidant gas is introduced into one of the manifolds 91, and this gas passes through the gas flow path 8 and is discharged from the manifold 92.

マニホールド９１にガス、例えばエアが導入されると、導入されたエアはガス拡散層を拡散していく。本発明の燃料電池セルにおいては、図２に示すように、ガス拡散層６を構成する多孔質基材層５内に撥水剤２３が偏在し、また微細多孔質層４が浸透している。この撥水剤２３が偏在してより多く存在する箇所１４は、燃料電池セルにおいてセパレータ７のガス流路溝８間のリブ９と接する箇所に対向する箇所に相当する。この箇所に撥水剤２３を多く偏在していることにより、前記多孔質基材層５の厚み方向における微細多孔質層４の厚みが、前記セパレータ７の凸部９が前記多孔質基材５層と接触する箇所近傍において、その他の箇所よりも小さくなっており、矢印に示すような、多孔質基材層５を通過してセパレータ７のガス流路溝８間を移動するガスの移動が妨げられることがなく、ガス拡散性が向上している。 When gas, for example, air is introduced into the manifold 91, the introduced air diffuses in the gas diffusion layer. In the fuel cell of the present invention, as shown in FIG. 2, the water repellent 23 is unevenly distributed in the porous base material layer 5 constituting the gas diffusion layer 6, and the fine porous layer 4 permeates. .. The portion 14 in which the water repellent 23 is unevenly distributed and more present corresponds to a portion facing the portion in contact with the rib 9 between the gas flow path grooves 8 of the separator 7 in the fuel cell. Since a large amount of the water repellent 23 is unevenly distributed in this portion, the thickness of the fine porous layer 4 in the thickness direction of the porous base material layer 5 is such that the convex portion 9 of the separator 7 is the porous base material 5. In the vicinity of the part in contact with the layer, it is smaller than the other parts, and as shown by the arrow, the movement of gas passing through the porous base material layer 5 and moving between the gas flow path grooves 8 of the separator 7 It is unimpeded and has improved gas diffusivity.

しかしながら、このガス拡散性が高いと、特にガス流路の入り口付近の領域、具体的には、多孔質基材層の面内において、セパレータのエア導入部であるマニホールド９１側の端部から、エア導入部の端部とエア出口部であるマニホールド９２側の端部の間の中間部までの範囲の領域において、燃料電池セルの性能が低下することがあることがわかった。 However, when this gas diffusivity is high, particularly in the region near the inlet of the gas flow path, specifically, in the plane of the porous base material layer, from the end portion on the manifold 91 side, which is the air introduction portion of the separator, It has been found that the performance of the fuel cell may deteriorate in the region up to the intermediate portion between the end portion of the air introduction portion and the end portion on the manifold 92 side which is the air outlet portion.

具体的には、多孔質基材の所定の箇所への微細多孔質層形成用塗工液の浸み込みを抑制した本発明の燃料電池セルと、多孔質基材への微細多孔質層形成用塗工液の浸み込みを抑制しない従来の燃料電池セルについて、図１０に示すような、エア導入部からの距離に対する発電性能の関係が予想される。 Specifically, the fuel cell of the present invention, which suppresses the infiltration of the coating liquid for forming a fine porous layer into a predetermined portion of the porous base material, and the formation of the fine porous layer on the porous base material. For a conventional fuel cell that does not suppress the infiltration of the coating liquid, the relationship of power generation performance with respect to the distance from the air introduction portion is expected as shown in FIG.

すなわち、セパレータのエア導入部の端部から、エア導入部の端部とエア出口部の端部の間の中間部までの範囲の領域においては、多孔質基材の所定の箇所への微細多孔質層形成用塗工液の浸み込みを抑制したガス拡散層を用いた場合、多孔質基材への微細多孔質層形成用塗工液の浸み込みを抑制しないガス拡散層を用いた場合と比較して発電性能が低下し、一方、エア導入部からの距離が遠くなるにつれて、エア導入部の端部とエア出口部の端部の間の中間部から、エア出口部の端部までの範囲の領域においては、多孔質基材への微細多孔質層形成用塗工液の浸み込みを抑制しないガス拡散層を用いた場合、多孔質基材の所定の箇所への微細多孔質層形成用塗工液の浸み込みを抑制したガス拡散層を用いた場合と比較して発電性能が低下することが予想される。 That is, in the region from the end of the air introduction portion of the separator to the intermediate portion between the end portion of the air introduction portion and the end portion of the air outlet portion, the porous substrate is microporous to a predetermined portion. When a gas diffusion layer that suppresses the penetration of the coating liquid for forming a layer is used, a gas diffusion layer that does not suppress the penetration of the coating liquid for forming a fine porous layer into the porous substrate was used. The power generation performance is lower than in the case, while as the distance from the air introduction part increases, from the middle part between the end part of the air introduction part and the end part of the air outlet part, the end part of the air outlet part. In the range up to, when a gas diffusion layer that does not suppress the infiltration of the coating liquid for forming the microporous layer into the porous substrate is used, the porous substrate is microporous to a predetermined location. It is expected that the power generation performance will be lower than when a gas diffusion layer that suppresses the penetration of the coating liquid for forming the layer is used.

そこで、多孔質基材の所定の箇所への微細多孔質層形成用塗工液の浸み込みを抑制した本発明の燃料電池セルと、多孔質基材への微細多孔質層形成用塗工液の浸み込みを抑制しない従来の燃料電池セルにおいて発電を行った際の、電解質膜の含水率を予測した。すると、図１１に示すような、エア導入部からの距離に対する電解質膜の含水率の関係が予測される。 Therefore, the fuel cell of the present invention, which suppresses the infiltration of the coating liquid for forming a fine porous layer into a predetermined portion of the porous base material, and the coating for forming a fine porous layer on the porous base material The water content of the electrolyte membrane was predicted when power was generated in a conventional fuel cell that does not suppress the infiltration of liquid. Then, as shown in FIG. 11, the relationship of the water content of the electrolyte membrane with respect to the distance from the air introduction portion is predicted.

すなわち、セパレータのエア導入部の端部から、エア導入部の端部とエア出口部の端部の間の中間部までの範囲の領域においては、多孔質基材の所定の箇所への微細多孔質層形成用塗工液の浸み込みを抑制したガス拡散層を用いた場合、多孔質基材への微細多孔質層形成用塗工液の浸み込みを抑制しないガス拡散層を用いた場合と比較して電解質膜の含水率が低下した。一方、エア導入部からの距離が遠くなるにつれて、エア導入部の端部とエア出口部の端部の間の中間部から、エア出口部の端部までの範囲の領域においては、多孔質基材への微細多孔質層形成用塗工液の浸み込みを抑制しないガス拡散層を用いた場合と、多孔質基材の所定の箇所への微細多孔質層形成用塗工液の浸み込みを抑制したガス拡散層を用いた場合のいずれにおいても電解質膜の含水率の低下は見られないことが予測された。 That is, in the region from the end of the air introduction portion of the separator to the intermediate portion between the end portion of the air introduction portion and the end portion of the air outlet portion, the porous substrate is microporous to a predetermined portion. When a gas diffusion layer that suppresses the infiltration of the coating liquid for forming the quality layer was used, a gas diffusion layer that did not suppress the penetration of the coating liquid for forming the fine porous layer into the porous substrate was used. The water content of the electrolyte membrane decreased as compared with the case. On the other hand, as the distance from the air introduction portion increases, the porous group is formed in the region from the intermediate portion between the end portion of the air introduction portion and the end portion of the air outlet portion to the end portion of the air outlet portion. When a gas diffusion layer that does not suppress the infiltration of the coating liquid for forming the fine porous layer into the material is used, and when the coating liquid for forming the fine porous layer is infiltrated into a predetermined portion of the porous base material. It was predicted that no decrease in the water content of the electrolyte membrane was observed when the gas diffusion layer with suppressed pouring was used.

以上の結果から、セパレータのエア導入部の端部から、エア導入部の端部とエア出口部の端部の間の中間部までの範囲の領域においては、ガス拡散性が高すぎるために電解質膜が乾燥し、プロトン伝導性が低下するため、結果として発電性能が低下すると考えられる。 From the above results, in the region from the end of the air introduction portion of the separator to the intermediate portion between the end of the air introduction portion and the end of the air outlet portion, the gas diffusivity is too high and the electrolyte It is considered that the film dries and the proton conductivity decreases, resulting in a decrease in power generation performance.

従って、本発明の他の態様においては、多孔質基材層の一方の面に撥水処理用塗工液を塗布する工程において使用する凹凸形状を有する部材として、第１の領域と第２の領域において凹凸の位相が半周期分ずれている部材を用いる。ここで、第１の領域は、多孔質基材層の面内において、セパレータのエア導入部の端部から、エア導入部の端部とエア出口部の端部の間の中間部までの範囲の領域であり、第２の領域は、エア導入部の端部とエア出口部の端部の間の中間部から、エア出口部の端部までの範囲の領域である。具体的には、このような凹凸形状を有する部材は、図１２及び図１３に示すように、凹凸形状を有する部材１３の左側の領域である第１の領域における溝（凹部）１６とリブ（凸部）１７と、凹凸形状を有する部材１３の左側の領域である第２の領域における溝（凹部）１６とリブ（凸部）１７は、エア導入部の端部とエア出口部の端部の間の中間部において凹凸の位相が半周期分ずれている。 Therefore, in another aspect of the present invention, as a member having a concavo-convex shape used in the step of applying the water-repellent coating liquid to one surface of the porous base material layer, the first region and the second A member whose unevenness is out of phase by half a cycle is used in the region. Here, the first region is a range from the end of the air introduction portion of the separator to the intermediate portion between the end of the air introduction portion and the end of the air outlet portion in the plane of the porous base material layer. The second region is a region in the range from the intermediate portion between the end portion of the air introduction portion and the end portion of the air outlet portion to the end portion of the air outlet portion. Specifically, as shown in FIGS. 12 and 13, the member having such an uneven shape includes a groove (recess) 16 and a rib (recessed portion) 16 in a first region which is a region on the left side of the member 13 having an uneven shape. The groove (concave portion) 16 and the rib (convex portion) 17 in the second region, which is the left region of the member 13 having the concave-convex shape, are the end portion of the air introduction portion and the end portion of the air outlet portion. The phase of the unevenness is shifted by half a cycle in the middle part between the two.

工程（１）においては、凹凸形状を有する部材の凸部を多孔質基材層と接触させた状態で撥水処理用塗工液を塗布することにより、多孔質基材層の、この凸部と接触させた箇所と対向する箇所に撥水剤を偏在させている。従って、第１の領域と第２の領域において凹凸の位相が半周期分ずれている部材を用いることにより、第１の領域と第２の領域において、撥水剤が偏在する箇所も半周期分ずれることになる。 In the step (1), the convex portion of the porous base material layer is applied by applying the water-repellent treatment coating liquid in a state where the convex portion of the member having the uneven shape is in contact with the porous base material layer. The water repellent is unevenly distributed in the place facing the place in contact with. Therefore, by using a member whose unevenness is out of phase by half a cycle in the first region and the second region, the portion where the water repellent is unevenly distributed in the first region and the second region is also half a cycle. It will shift.

こうして撥水剤が偏在する箇所を半周期分ずらした多孔質膜に微細多孔質膜形成用塗工液を塗布すると、撥水剤が偏在する箇所においては微細多孔質膜形成用塗工液の浸み込みが抑制され、微細多孔質膜の厚みは小さくなる。ところが、第１の領域と第２の領域においては撥水剤が偏在する箇所が半周期分ずれているため、微細多孔質膜の厚みが小さい箇所も、第１の領域と第２の領域において半周期分ずれることになる。 When the coating liquid for forming a fine porous film is applied to the porous film in which the portion where the water repellent is unevenly distributed is shifted by half a cycle, the coating liquid for forming the fine porous film is applied to the portion where the water repellent is unevenly distributed. Penetration is suppressed and the thickness of the fine porous membrane is reduced. However, in the first region and the second region, the locations where the water repellent is unevenly distributed are deviated by half a cycle, so that the locations where the fine porous membrane is thin are also in the first region and the second region. It will be off by half a cycle.

こうして得られたガス拡散層の第２の領域において前記凹凸形状を有する部材の凸部と接触した箇所と対向する箇所にセパレータの凸部が接触するようにセパレータを配置することにより、得られた燃料電池セルでは、第２の領域においては、図２に示すように、撥水剤２３が偏在してより多く存在する箇所１４が、燃料電池セルにおいてセパレータ７のガス流路溝８間のリブ９と接する箇所に対向する箇所に相当し、多孔質基材層５の厚み方向における微細多孔質層４の厚みが、セパレータ７の凸部９が多孔質基材５層と接触する箇所近傍において、その他の箇所よりも小さくなっており、矢印に示すような、多孔質基材層５を通過してセパレータ７のガス流路溝８間を移動するガスの移動が妨げられることがなく、ガス透過性の低下を抑制することができる。 It was obtained by arranging the separator in the second region of the gas diffusion layer thus obtained so that the convex portion of the separator contacts the portion facing the convex portion of the member having the uneven shape. In the fuel cell, in the second region, as shown in FIG. 2, the portion 14 in which the water repellent 23 is unevenly distributed and more is present is a rib between the gas flow path grooves 8 of the separator 7 in the fuel cell. Corresponding to the portion facing the portion in contact with 9, the thickness of the microporous layer 4 in the thickness direction of the porous substrate layer 5 is in the vicinity of the portion where the convex portion 9 of the separator 7 contacts the porous substrate 5 layer. , It is smaller than other parts, and as shown by the arrow, the movement of gas that passes through the porous base material layer 5 and moves between the gas flow path grooves 8 of the separator 7 is not hindered, and the gas is not hindered. It is possible to suppress a decrease in permeability.

一方、第１の領域においては、図１４に示すように、撥水剤２３が偏在してより多く存在する箇所１４が、燃料電池セルにおいてセパレータ７のガス流路溝８に対向する箇所に相当し、多孔質基材層５の厚み方向における微細多孔質層４の厚みが、セパレータ７の凸部９が多孔質基材５層と接触する箇所近傍において、その他の箇所よりも厚くなっており、多孔質基材層５を通過してセパレータ７のガス流路溝８間を移動するガスの移動が一部妨げられ、ガス拡散性を抑制することによって、電解質膜の乾燥を抑制することができる。 On the other hand, in the first region, as shown in FIG. 14, the portion 14 in which the water repellent 23 is unevenly distributed and more present corresponds to the portion facing the gas flow path groove 8 of the separator 7 in the fuel cell. However, the thickness of the microporous layer 4 in the thickness direction of the porous substrate layer 5 is thicker in the vicinity of the portion where the convex portion 9 of the separator 7 comes into contact with the porous substrate 5 layer than in other portions. , The movement of the gas passing through the porous base material layer 5 and moving between the gas flow path grooves 8 of the separator 7 is partially hindered, and the gas diffusivity is suppressed, thereby suppressing the drying of the electrolyte membrane. it can.

１ 固体高分子電解質膜
２ 触媒電極層
３ 膜電極接合体
４ 微細多孔質層
５ 多孔質基材層
６ ガス拡散層
７ セパレータ
８ ガス流路溝
１０ 燃料電池セル
１１ 多孔質基材層
１２ 搬送ローラー
１３ 搬送ベルト（又は凹凸部材）
１５ 突起
１６ 凸部
１７ 凹部
２０ 撥水処理用塗工装置
２１ ダイヘッド
２２ 撥水処理用塗工液
２３ 撥水剤
３０ 第１の加熱装置
３１ ヒーター
４０ 第２の塗工装置
４１ ダイヘッド
４２ 微細多孔質層形成用塗工液
５０ 第２の加熱装置
５１ ヒーター
６０ プレス装置
６１ プレス板 1 Solid polymer electrolyte membrane 2 Catalytic electrode layer 3 Membrane electrode assembly 4 Fine porous layer 5 Porous base material layer 6 Gas diffusion layer 7 Separator 8 Gas flow path groove 10 Fuel cell cell 11 Porous base material layer 12 Conveyor roller 13 Conveyance belt (or uneven member)
15 Protrusions 16 Convex 17 Concave 20 Water repellent coating device 21 Die head 22 Water repellent coating liquid 23 Water repellent 30 First heating device 31 Heater 40 Second coating device 41 Die head 42 Microporous Coating liquid for layer formation 50 Second heating device 51 Heater 60 Press device 61 Press plate

Claims (4)

多孔質基材層と微細多孔質層とを備えた燃料電池用ガス拡散層と、セパレータとを備えている燃料電池セルの製造方法であって、以下の工程
（１）前記多孔質基材層の一方の面に、撥水処理用塗工液を塗布すること、
（２）前記撥水処理用塗工液を塗布した前記多孔質基材層を、加熱して乾燥させること、
（３）前記多孔質基材層の、前記撥水処理用塗工液を塗布した面とは反対の面に、微細多孔質層形成用塗工液を塗布すること、
（４）前記微細多孔質層形成用塗工液を塗布した前記多孔質基材層を、加熱して焼成すること、及び
（５）前記多孔質基材層の、前記微細多孔質層形成用塗工液を塗布した面とは反対の面に、凹凸形状を有するセパレータを配置すること
を含み、前記工程（１）において、凹凸形状を有する部材の凸部を、前記多孔質基材層の前記撥水処理用塗工液を塗布する面とは反対側の面と接触させた状態で、前記撥水処理用塗工液の塗布を行い、かつ
前記工程（５）において、前記多孔質基材の、前記凹凸形状を有する部材の凸部を接触させた箇所と対向する箇所に前記セパレータの凸部が接触するように前記セパレータを配置する、燃料電池セルの製造方法。 A method for manufacturing a fuel cell cell including a gas diffusion layer for a fuel cell having a porous base material layer and a fine porous layer and a separator. The following steps (1) The porous base material layer Applying a water-repellent coating solution to one surface,
(2) The porous base material layer coated with the water-repellent coating liquid is heated and dried.
(3) Applying the coating liquid for forming a fine porous layer to the surface of the porous base material layer opposite to the surface to which the coating liquid for water repellent treatment is applied.
(4) The porous base material layer coated with the coating liquid for forming the fine porous base material is heated and fired, and (5) for forming the fine porous base material of the porous base material layer. Including arranging a separator having an uneven shape on a surface opposite to the surface on which the coating liquid is applied, in the step (1), the convex portion of the member having an uneven shape is formed on the porous base material layer. The water-repellent coating liquid is applied in a state of being in contact with the surface opposite to the surface on which the water-repellent coating liquid is applied, and the porous group is applied in the step (5). A method for manufacturing a fuel cell, wherein the separator is arranged so that the convex portion of the separator comes into contact with a portion of the material that is in contact with the convex portion of the member having the uneven shape. 前記工程（１）において使用する凹凸形状を有する部材が、第１の領域と第２の領域において凹凸の位相が半周期分ずれており、第１の領域が、前記多孔質基材層の面内において、前記セパレータのエア導入部の端部から、エア導入部の端部とエア出口部の端部の間の中間部までの範囲の領域であり、第２の領域が、エア導入部の端部とエア出口部の端部の間の中間部から、エア出口部の端部までの範囲の領域であり、
前記工程（５）において、前記工程（１）において前記多孔質基材層の第２の領域において前記凹凸形状を有する部材の凸部と接触した箇所と対向する箇所に前記セパレータの凸部が接触するように前記セパレータを配置する、
請求項１に記載の燃料電池セルの製造方法。 The member having the concave-convex shape used in the step (1) is out of phase with the unevenness by half a cycle in the first region and the second region, and the first region is the surface of the porous base material layer. Within, the region ranges from the end of the air introduction portion of the separator to the intermediate portion between the end of the air introduction portion and the end of the air outlet portion, and the second region is the air introduction portion of the air introduction portion. The area from the middle part between the end part and the end part of the air outlet part to the end part of the air outlet part.
In the step (5), the convex portion of the separator comes into contact with a portion of the second region of the porous base material layer that is in contact with the convex portion of the member having the uneven shape in the step (1). The separator is arranged so as to
The method for manufacturing a fuel cell according to claim 1. 多孔質基材層と微細多孔質層とを備えた燃料電池用ガス拡散層と、セパレータとを備えている燃料電池セルであって、前記多孔質基材層の厚み方向における微細多孔質層の厚みが、前記セパレータの凸部が前記多孔質基材層と接触する箇所近傍において、その他の箇所よりも小さい、燃料電池セル。 A fuel cell cell provided with a gas diffusion layer for a fuel cell having a porous base material layer and a fine porous layer and a separator, which is a fine porous layer in the thickness direction of the porous base material layer. A fuel cell whose thickness is smaller in the vicinity of a portion where the convex portion of the separator contacts the porous base material layer than in other portions. 前記燃料電池セルが第１の領域と第２の領域を有し、
第１の領域が、前記多孔質基材層の面内において、前記セパレータのエア導入部の端部から、エア導入部の端部とエア出口部の端部の間の中間部までの範囲の領域であり、第２の領域が、エア導入部の端部とエア出口部の端部の間の中間部から、エア出口部の端部までの範囲の領域であり、
第１の領域において、前記多孔質基材層の厚み方向における微細多孔質層の厚みが、前記セパレータの凸部が前記多孔質基材層と接触する箇所近傍において、その他の箇所よりも大きく、第２の領域において、前記多孔質基材層の厚み方向における微細多孔質層の厚みが、前記セパレータの凸部が前記多孔質基材層と接触する箇所近傍において、その他の箇所より小さい、請求項３に記載の燃料電池セル。 The fuel cell has a first region and a second region.
The first region ranges from the end of the air introduction portion of the separator to the intermediate portion between the end portion of the air introduction portion and the end portion of the air outlet portion in the plane of the porous base material layer. It is a region, and the second region is a region in the range from the intermediate portion between the end portion of the air introduction portion and the end portion of the air outlet portion to the end portion of the air outlet portion.
In the first region, the thickness of the microporous layer in the thickness direction of the porous base material layer is larger in the vicinity of the portion where the convex portion of the separator comes into contact with the porous substrate layer than in the other portions. In the second region, the thickness of the microporous layer in the thickness direction of the porous base material layer is smaller than the other parts in the vicinity of the portion where the convex portion of the separator contacts the porous base material layer. Item 3. The fuel cell according to Item 3.
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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001236976A (en) * 2000-02-22 2001-08-31 Sanyo Electric Co Ltd Fuel cell
JP2004327358A (en) * 2003-04-28 2004-11-18 Nissan Motor Co Ltd Polymer electrolyte fuel cell
JP2009224279A (en) * 2008-03-18 2009-10-01 Toyota Motor Corp Manufacturing method of assembly for fuel cell
JP2015050073A (en) * 2013-09-03 2015-03-16 トヨタ自動車株式会社 Method for manufacturing gas diffusion layer for fuel battery
JP2015191826A (en) * 2014-03-28 2015-11-02 東レ株式会社 Method for manufacturing gas diffusion electrode, and manufacturing device therefor

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001236976A (en) * 2000-02-22 2001-08-31 Sanyo Electric Co Ltd Fuel cell
JP2004327358A (en) * 2003-04-28 2004-11-18 Nissan Motor Co Ltd Polymer electrolyte fuel cell
JP2009224279A (en) * 2008-03-18 2009-10-01 Toyota Motor Corp Manufacturing method of assembly for fuel cell
JP2015050073A (en) * 2013-09-03 2015-03-16 トヨタ自動車株式会社 Method for manufacturing gas diffusion layer for fuel battery
JP2015191826A (en) * 2014-03-28 2015-11-02 東レ株式会社 Method for manufacturing gas diffusion electrode, and manufacturing device therefor

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