JP5057017B2 - Diffusion layer manufacturing apparatus and manufacturing method - Google Patents

Description

  The present invention relates to a diffusion layer manufacturing apparatus and a manufacturing method.

  Conventionally, a fuel cell including a membrane / electrode assembly formed by providing a catalyst layer for an electrode on both surfaces of an electrolyte membrane has been proposed and put into practical use. In a fuel cell system including such a fuel cell, anode gas is supplied to one catalyst layer (anode electrode) constituting the membrane-electrode assembly of the fuel cell, and cathode gas is supplied to the other electrode (cathode side electrode). Then, it generates electricity by causing an electrochemical reaction.

By the way, the catalyst layer of the membrane / electrode assembly of a fuel cell is generally covered with a “diffusion layer” having a function of diffusing reaction gas (anode gas and cathode gas) supplied from the outside. is there. Conventionally, carbon paper or carbon cloth has been adopted as the base material for such a diffusion layer. However, in recent years, for the purpose of improving water repellency and the like, there are two types of base materials such as carbon fiber woven fabrics having different characteristics from each other. A technique for forming a thin diffusion layer by applying a functional material is proposed (see, for example, Patent Document 1).
JP-A-10-261421

  However, in the technique as described in Patent Document 1, (1) a step of applying a first functional material having flow characteristics that easily impregnates a base material, impregnating the base material, and drying, (2) Applying two types of functional materials to the substrate through separate steps of applying and drying a second functional material having flow characteristics that are difficult to impregnate the substrate onto the first functional material layer Was. For this reason, there has been a problem that a relatively large amount of labor and time are required to manufacture the diffusion layer.

  This invention is made | formed in view of this situation, and it aims at reducing the effort and time which are required when manufacturing the diffusion layer provided in the membrane electrode assembly of a fuel cell.

  In order to achieve the above object, a diffusion layer manufacturing apparatus according to the present invention is an apparatus for manufacturing a diffusion layer by adding first and second functional materials having different characteristics to a base material for a diffusion layer. A base material transport means for transporting the base material in a predetermined direction, and a functional material for sequentially adding the first and second functional materials to the base material transported in the predetermined direction by the base material transport means And an adding means.

  The method for producing a diffusion layer according to the present invention is a method for producing a diffusion layer by adding first and second functional materials having different characteristics to a substrate for the diffusion layer, wherein the substrate is predetermined. A base material transporting process for transporting in the direction of, and a functional material addition process for sequentially adding the first and second functional materials to the base material transported in a predetermined direction in the base material transporting process. It is to be prepared.

  According to such a configuration and method, a diffusion layer is manufactured by sequentially adding two types of functional materials (first and second functional materials) having different characteristics to a substrate conveyed in a predetermined direction. Therefore, the process for manufacturing the diffusion layer can be simplified. Therefore, it is possible to reduce labor and time required for manufacturing the diffusion layer.

  In the manufacturing apparatus (method), a first functional material having flow characteristics that are easily absorbed into the base material and a second functional material having flow characteristics that are difficult to be absorbed inside the base material are added. Functional material adding means (process) can be employed. In such a case, a functional material addition means (step) for adding the first functional material prior to the second functional material in terms of time can be employed.

  Further, in the manufacturing apparatus (method), a first functional material configured by dispersing a specific functional substance in a solvent is adopted, and the first functional material is made longer than the second functional material. Therefore, a functional material addition means (step) for adding the second functional material after the prior addition before the solvent of the first functional material is vaporized can be employed.

  Further, the manufacturing apparatus has a single head for storing the first and second functional materials in a separated state, and the first and second functional materials are sequentially ejected from the head and applied. Functional material addition means can be employed. In the manufacturing method, the functional material addition step of sequentially discharging and applying the first and second functional materials from a single head that stores the first and second functional materials in a separated state. Can be adopted.

  According to such a configuration and method, it is possible to apply two types of functional materials (first and second functional materials) to the substrate using a single head. Therefore, since it is not necessary to use a plurality of heads when applying two types of functional materials to the substrate, the number of various devices (pumps, back rolls, etc.) provided corresponding to the number of heads can be reduced. Can do. As a result, the cost required for manufacturing the diffusion layer can be reduced. In addition, since it is not necessary to control a plurality of heads in conjunction with each other, the head control mode is simplified, and as a result, the process for manufacturing the diffusion layer can be further simplified.

  According to the present invention, it is possible to reduce labor and time required for manufacturing a diffusion layer provided in a membrane / electrode assembly of a fuel cell.

  Embodiments of the present invention will be described below with reference to the drawings. In the following embodiments, a manufacturing apparatus and a manufacturing method for manufacturing a diffusion layer provided in a solid polymer electrolyte fuel cell suitable for in-vehicle use will be described.

<First Embodiment>
First, the diffusion layer manufacturing apparatus and manufacturing method according to the first embodiment of the present invention will be described with reference to FIGS. 1 and 2.

  Initially, the structure of the manufacturing apparatus which concerns on this embodiment is demonstrated using FIG. The manufacturing apparatus includes a base material transport unit (not shown) that transports the base material 10 for the diffusion layer in a predetermined direction and a base material 10 that is transported in the predetermined direction by the base material transport unit. Functional material addition means for sequentially adding the functional material 11 and the second functional material 12.

  In the present embodiment, a porous material such as carbon cloth or carbon paper is employed as the base material 10. In the present embodiment, a low-viscosity, water-repellent and conductive paste material having flow characteristics that are easily absorbed into the base material 10 is employed as the first functional material 11, and the second functional material is used. 12, a highly viscous water-repellent / conductive paste material having flow characteristics that are difficult to be absorbed inside the substrate 10 is employed.

  The first and second functional materials 11 and 12 are prepared by mixing a water-repellent material and a conductive material in a predetermined solvent. Examples of water repellent materials include PTFE (polytetrafluoroethylene), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, polychlorotrifluoroethylene, polyvinylidene fluoride, polyvinyl fluoride, A tetrafluoroethylene-ethylene copolymer or the like can be employed. Moreover, carbon powder etc. are employable as an electroconductive material.

  The substrate conveying means includes a winding roller that winds up the substrate 10, a delivery roller that sends out the substrate 10, and a conveying roller that conveys the substrate 10 in a predetermined direction while supporting the substrate 10 at a predetermined interval. . In the present embodiment, a base material transport means for transporting the base material 10 in the direction of arrow A in FIG. 1 is employed.

  As shown in FIG. 1, the functional material addition means is connected to the first tank (not shown) for storing the first functional material 11, and the first functional material 11 is connected to the first tank as a base material. The first discharge head 1 that discharges to the second tank 10, the second tank (not shown) that stores the second functional material 12, and the second functional material 12 that is connected to the second tank 10 From the second discharge head 2 that discharges the liquid, the back roll 5 that is disposed so as to face the first discharge head 1 with the base material 10 interposed therebetween, the first discharge head 1, and the second discharge head 2. It is comprised from the control apparatus etc. which are not illustrated which control the timing of discharge of this functional material.

  In the present embodiment, for the purpose of adding (impregnating and applying) a functional material to both surfaces of the substrate 10, the first ejection head 1 is disposed on one surface side of the substrate 10 as shown in FIG. 1. The second ejection head 2 is disposed on the other surface side of the substrate 10. In addition, as shown in FIG. 1, the first functional material 11 is made longer than the second functional material 12 by disposing the first ejection head 1 on the upstream side of the second ejection head 2. Therefore, the ink is discharged to the base material 10 in advance. In the present embodiment, in order to impregnate the base material 10 with the first functional material 11, the base material 10 is sandwiched between the first discharge head 1 and the back roll 5 to thereby apply a predetermined coating. Apply working pressure. The second functional material 12 is discharged from the second discharge head 2 and applied to the surface of the substrate 10 (without applying a coating pressure). In addition, when a coating pressure is required, a back roll is arrange | positioned so that the base material 10 may be pinched and the 2nd discharge head 2 may be opposed.

  The first and second ejection heads 1 and 2 have slit-like ejection ports 1a and 2a. The lengths of the discharge ports 1a and 2a (the dimensions in the direction perpendicular to the paper surface in FIG. 1) are determined so as to correspond to the substrate dimensions in the direction perpendicular to the transport direction. Further, the width of the discharge ports 1a and 2a (dimensions in the transport direction in FIG. 1), the clearance between the first discharge head 1 and the substrate 10, and the clearance between the second discharge head 2 and the substrate 10. Can be appropriately set according to the viscosity of the first functional material 11 and the second functional material 12, the conveyance speed of the substrate 10, and the like.

  Next, a method for manufacturing the diffusion layer according to this embodiment will be described.

  First, the base material 10 for the diffusion layer is prepared, and a paste-like functional material (first functional property) is prepared by mixing a water repellent material such as PTFE and a conductive material such as carbon powder in a predetermined solvent. The material 11 and the second functional material 12) are prepared (material preparation step). Next, as shown in FIG. 1, the base material 10 is transported in a predetermined direction using the base material transport means (base material transport process). Then, the first functional material 11 is discharged from the first discharge head 1 to the base material 10 transported by the base material transport means, and the first functional material 11 is impregnated inside the base material 10. At the same time, the second functional material 12 is ejected from the second ejection head 2 to apply the second functional material 12 to the surface of the substrate 10 (functional material addition step).

  Thereafter, the first functional material 11 impregnated in the base material 10 and the second functional material 12 applied to the surface of the base material 10 are dried, whereby diffusion as shown in FIG. Layer 20 can be obtained. A water repellent / conductive layer made of the first functional material 11 is formed on one surface of the diffusion layer 20. In addition, a water repellent / conductive layer made of the second functional material 12 is formed on the other surface of the diffusion layer 20.

  According to the manufacturing apparatus (manufacturing method) according to the embodiment described above, the two types of functional materials (the first functional material 11 and the first functional material 11) having different characteristics with respect to the base material 10 conveyed in a predetermined direction. Since the diffusion layer 20 can be manufactured by sequentially adding the second functional material 12), the process for manufacturing the diffusion layer 20 can be simplified. Therefore, it is possible to reduce labor and time required for manufacturing the diffusion layer 20.

Second Embodiment
Next, with reference to FIGS. 3 and 4, a diffusion layer manufacturing apparatus and method according to a second embodiment of the present invention will be described. In addition, the base material and functional material used by this embodiment shall be the same as the base material 10 and functional material 11 and 12 which were used by 1st Embodiment. The configurations of the ejection head and the back roll employed in the present embodiment are substantially the same as the configurations of the ejection heads 1 and 2 and the back roll 5 employed in the first embodiment.

  Initially, the structure of the manufacturing apparatus which concerns on this embodiment is demonstrated using FIG. The manufacturing apparatus includes a base material transport unit (not shown) that transports the base material 10 for the diffusion layer in a predetermined direction and a base material 10 that is transported in the predetermined direction by the base material transport unit. Functional material addition means for sequentially adding the functional material 11 and the second functional material 12.

  The substrate conveying means includes a winding roller that winds up the substrate 10, a delivery roller that sends out the substrate 10, and a conveying roller that conveys the substrate 10 in a predetermined direction while supporting the substrate 10 at a predetermined interval. . In the present embodiment, a base material transport means for transporting the base material 10 in the direction of arrow B in FIG.

  As shown in FIG. 3, the functional material adding means is connected to the first tank (not shown) for storing the first functional material 11, and is connected to the first tank, and the first functional material 11 is used as a base material. The first discharge head 1 that discharges to the second tank 10, the second tank (not shown) that stores the second functional material 12, and the second functional material 12 that is connected to the second tank 10 The second discharge head 2 that discharges the liquid, the back roll 5 that is disposed so as to face the first discharge head 1 and the second discharge head 2 with the base material 10 interposed therebetween, the first discharge head 1 and The controller includes a control device (not shown) that controls the timing of discharging the functional material from the second discharge head 2.

  In the present embodiment, for the purpose of adding (impregnating and applying) a functional material only to one side of the substrate 10, both the first ejection head 1 and the second ejection head 2 are connected as shown in FIG. It arrange | positions at the one surface side of the base material 10. FIG. In addition, as shown in FIG. 3, the first functional material 11 is made longer than the second functional material 12 by disposing the first ejection head 1 on the upstream side of the second ejection head 2. Therefore, the ink is discharged to the base material 10 in advance. Particularly in the present embodiment, the second functional material 12 is applied before the solvent of the first functional material 11 is vaporized. Also in the present embodiment, in order to impregnate the base material 10 with the first functional material 11, the base material 10 is sandwiched between the first discharge head 1 and the back roll 5 so as to obtain a predetermined coating. Apply working pressure. The second functional material 12 is discharged from the second discharge head 2 and applied to the surface of the substrate 10 (without applying a coating pressure).

  Next, a method for manufacturing the diffusion layer according to this embodiment will be described.

  First, the base material 10 for the diffusion layer is prepared, and a paste-like functional material (first functional property) is prepared by mixing a water repellent material such as PTFE and a conductive material such as carbon powder in a predetermined solvent. The material 11 and the second functional material 12) are prepared (material preparation step). Next, as shown in FIG. 3, the base material 10 is transported in a predetermined direction using the base material transport means (base material transport process). Then, the first functional material 11 is discharged from the first discharge head 1 to the base material 10 transported by the base material transport means, and the first functional material 11 is impregnated inside the base material 10. At the same time, the second functional material 12 is ejected from the second ejection head 2 to apply the second functional material 12 to the surface of the base material 10 impregnated with the first functional material 11 ( Functional material addition process). At this time, the second functional material 12 is applied before the solvent of the first functional material 11 is vaporized.

  Thereafter, a first functional material 11 impregnated in the interior of the base material 10, a second functional material 12 applied to the surface of the base material 10 (impregnated with the first functional material 11), Is dried, a diffusion layer 21 as shown in FIG. 4 can be obtained. Two layers of a water repellent / conductive layer made of the first functional material 11 and a water repellent / conductive layer made of the second functional material 12 are formed on one surface of the diffusion layer 21. It becomes.

  According to the manufacturing apparatus (manufacturing method) according to the embodiment described above, the two types of functional materials (the first functional material 11 and the first functional material 11) having different characteristics with respect to the base material 10 conveyed in a predetermined direction. Since the second functional material 12) can be sequentially added to manufacture the diffusion layer 21, the process for manufacturing the diffusion layer 21 can be simplified. Therefore, it is possible to reduce labor and time required for manufacturing the diffusion layer 21. Moreover, since the 2nd functional material 12 is apply | coated before the 1st functional material 11 dries, the adhesiveness of the 1st functional material 11 and the 2nd functional material 12 can be improved. It becomes possible.

<Third Embodiment>
Next, with reference to FIG.4 and FIG.5, the manufacturing apparatus and manufacturing method which concern on 3rd Embodiment of this invention are demonstrated. In addition, the base material and functional material used by this embodiment shall be the same as the base material 10 and functional material 11 and 12 which were used by 1st Embodiment. In addition, the configurations of the base material transport unit and the back roll employed in the present embodiment are substantially the same as the configurations of the base material transport unit and the back roll 5 employed in the first embodiment.

  Initially, the structure of the manufacturing apparatus which concerns on this embodiment is demonstrated using FIG. The manufacturing apparatus includes a base material transport unit (not shown) that transports the base material 10 for the diffusion layer in a predetermined direction and a base material 10 that is transported in the predetermined direction by the base material transport unit. Functional material addition means for sequentially adding the functional material 11 and the second functional material 12.

  As shown in FIG. 5, the functional material addition means includes a first tank (not shown) that stores the first functional material 11 and a second (not shown) that stores the second functional material 12. A two-liquid discharge head 4 for discharging the first functional material 11 and the second functional material 12 to the base material 10 connected to the tank, the first tank and the second tank, and the base material 10 are sandwiched. The back roll 5 is disposed so as to face the two-liquid discharge head 4, and includes a control device (not shown) that controls the discharge timing of each functional material from the two-liquid discharge head 4. .

  As shown in FIG. 5, the two-liquid ejection head 4 includes a slit-shaped first ejection port 4 a for ejecting the first functional material 11 and a slit for ejecting the second functional material 12. Second discharge port 4b, and a partition member 4c that partitions the second discharge port 4a and the second discharge port 4b. The first functional material 11 supplied from the first tank is discharged from the first discharge port 4a to the base material 10 via the first flow path 4d in the head. The second functional material 12 supplied from the second tank is discharged from the second discharge port 4b to the substrate 10 via the second flow path 4e in the head. The first discharge port 4a of the two-liquid discharge head 4 is disposed upstream of the second discharge port 4b, and the first functional material 11 precedes the second functional material 12 in time. And discharged onto the substrate 10. In the present embodiment, the second functional material 12 is applied before the solvent of the first functional material 11 is vaporized.

  Further, in the present embodiment, in order to impregnate the base material 10 with the first functional material 11, the base material 10 is sandwiched between the first discharge port 4 a of the two-liquid discharge head 4 and the back roll 5. By doing so, a predetermined coating pressure is applied. On the other hand, a relatively wide clearance is provided between the second discharge port 4b of the two-liquid discharge head 4 and the base material 10, and the second functional material 12 discharged from the second discharge port 4b is The coating is applied to the surface of the substrate 10 without applying a coating pressure.

  The lengths of the discharge ports 4a and 4b of the two-liquid discharge head 4 (the dimensions in the direction perpendicular to the paper surface in FIG. 5) are determined so as to correspond to the substrate dimensions in the direction perpendicular to the transport direction. Is done. Further, the width of each discharge port 4a, 4b (dimension in the transport direction in FIG. 5), the clearance between the first discharge port 4a and the substrate 10, and the clearance between the second discharge port 4b and the substrate 10 are as follows. The viscosity can be appropriately set according to the viscosity of the first functional material 11 and the second functional material 12, the conveyance speed of the base material 10, and the like.

  Next, a method for manufacturing the diffusion layer according to this embodiment will be described.

  First, the base material 10 for the diffusion layer is prepared, and a paste-like functional material (first functional property) is prepared by mixing a water repellent material such as PTFE and a conductive material such as carbon powder in a predetermined solvent. The material 11 and the second functional material 12) are prepared (material preparation step). Next, as shown in FIG. 5, the base material 10 is transported in a predetermined direction using the base material transport means (base material transport process). And the 1st functional material 11 is discharged from the 1st discharge port 4a of the discharge head 4 for 2 liquids with respect to the base material 10 conveyed by a base material conveyance means, and the 1st inside of the base material 10 is made into 1st. The functional material 11 is impregnated, and the second functional material 12 is discharged from the second discharge port 4b, and the second functional material is applied to the surface of the base material 10 impregnated with the first functional material 11. 12 is applied (functional material addition step). At this time, the second functional material 12 is applied before the solvent of the first functional material 11 is vaporized.

  Thereafter, a first functional material 11 impregnated in the interior of the base material 10, a second functional material 12 applied to the surface of the base material 10 (impregnated with the first functional material 11), Is dried, a diffusion layer 21 as shown in FIG. 4 can be obtained. Two layers of a water repellent / conductive layer made of the first functional material 11 and a water repellent / conductive layer made of the second functional material 12 are formed on one surface of the diffusion layer 21. It becomes.

  According to the manufacturing apparatus (manufacturing method) according to the embodiment described above, the two types of functional materials (the first functional material 11 and the first functional material 11) having different characteristics with respect to the base material 10 conveyed in a predetermined direction. Since the second functional material 12) can be sequentially added to manufacture the diffusion layer 21, the process for manufacturing the diffusion layer 21 can be simplified. Therefore, it is possible to reduce labor and time required for manufacturing the diffusion layer 21. Moreover, since the 2nd functional material 12 is apply | coated before the 1st functional material 11 dries, the adhesiveness of the 1st functional material 11 and the 2nd functional material 12 can be improved. It becomes possible. Furthermore, it is possible to add two types of functional materials by employing a single head (two-liquid ejection head 4). Therefore, various parts (back roll, etc.) required for each head can be reduced, so that the overall configuration of the apparatus can be simplified, and the contact position between the head and the substrate is reduced (one place). Therefore, it is possible to stabilize the conveyance state of the base material 10.

  In the first and second embodiments, an example is shown in which two types of functional materials are added to the substrate using two ejection heads. However, the number of ejection heads and the types of functional materials are the same. It is not limited. For example, as shown in FIG. 6, three types of functional materials (first function) are used by using three ejection heads (first ejection head 1, second ejection head 2, and third ejection head 3). The functional material 11, the second functional material 12, and the third functional material 13) can also be added (impregnated, applied) to the base material 10.

It is a block diagram which shows the structure of the manufacturing apparatus of the diffused layer which concerns on 1st Embodiment of this invention. It is sectional drawing of the diffusion layer manufactured with the manufacturing apparatus which concerns on 1st Embodiment of this invention. It is a block diagram which shows the structure of the manufacturing apparatus of the diffused layer which concerns on 2nd Embodiment of this invention. It is sectional drawing of the diffusion layer manufactured with the manufacturing apparatus which concerns on 2nd Embodiment of this invention. It is a block diagram which shows the structure of the manufacturing apparatus of the diffused layer which concerns on 3rd Embodiment of this invention. It is a block diagram which shows the structure of the modification of the manufacturing apparatus of the diffusion layer which concerns on 1st and 2nd embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... 1st discharge head (functional material addition means), 2 ... 2nd discharge head (functional material addition means), 4 ... discharge head for 2 liquids (single head, functional material addition means), 5 ... Back roll (functional material addition means), 11 ... 1st functional material, 12 ... 2nd functional material, 20 * 21 ... Diffusion layer.

Claims (8)

An apparatus for producing a diffusion layer by adding first and second functional materials having different properties to a base material for a diffusion layer,
Base material transport means for transporting the base material in a predetermined direction;
Functional material addition means for sequentially adding the first and second functional materials to the base material transported in a predetermined direction by the base material transport means ;
The functional material adding means has a single head for storing the first and second functional materials in a separated state, and sequentially discharges the first and second functional materials from the head. To apply,
Diffusion layer manufacturing equipment. The functional material adding means includes the first functional material having flow characteristics that are easily absorbed in the base material, and the second functional material having flow characteristics that are difficult to be absorbed in the base material. And,
The apparatus for manufacturing a diffusion layer according to claim 1. The functional material addition means is for adding the first functional material in advance of the second functional material in time.
The apparatus for manufacturing a diffusion layer according to claim 2. The first functional material is configured by dispersing a specific functional substance in a solvent,
The functional material adding means is for adding the second functional material after adding the first functional material and before the solvent of the first functional material is vaporized.
The apparatus for manufacturing a diffusion layer according to claim 1. A method for producing a diffusion layer by adding first and second functional materials having different properties to a base material for a diffusion layer,
A base material transporting step for transporting the base material in a predetermined direction;
A functional material addition step of sequentially adding the first and second functional materials to the base material transported in a predetermined direction in the base material transport step ,
In the functional material addition step, the first and second functional materials are sequentially ejected and applied from a single head that stores the first and second functional materials in a separated state.
A method for manufacturing a diffusion layer. In the functional material addition step, the first functional material having flow characteristics that are easily absorbed inside the base material, and the second functional material having flow characteristics that are difficult to be absorbed inside the base material. And add,
The method for producing a diffusion layer according to claim 5 . In the functional material addition step, the first functional material is added prior to the second functional material in time.
The manufacturing method of the diffusion layer of Claim 6 . As the first functional material, a material constituted by dispersing a specific functional substance in a solvent is adopted,
In the functional material addition step, after the first functional material is added , the second functional material is added before the solvent of the first functional material is vaporized.
The method for producing a diffusion layer according to claim 5 .

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