JP5066780B2 - Electrode catalyst layer forming apparatus for fuel cell - Google Patents

Description

  The present invention relates to an electrode catalyst layer forming apparatus for a fuel cell, and relates to an improvement in an electrode catalyst layer forming apparatus for a fuel cell, in which an electrode catalyst layer for promoting a reaction of an electrode of a fuel cell is formed on an electrolyte membrane.

  Conventionally, in an electrode catalyst layer forming apparatus for a fuel cell in which a catalyst-carrying solution is applied to an electrolyte membrane to form an electrode catalyst layer, deformation of the thin film due to wetting or drying of the electrolyte membrane during application of this solution is reduced. Improvements have been made.

  For example, in the liquid coating apparatus disclosed in JP-A No. 2002-166213 (Patent Document 1), a thin film (for example, an electrolyte membrane) is placed on a transport belt having a large number of suction holes, and the back side of the transport belt is sucked. It is disclosed that an electrode catalyst layer is formed by applying a liquid to be an electrode catalyst layer while adsorbing and transporting a thin film onto a conveyor belt through a suction hole having a negative pressure, and drying the liquid. The conveyor belt is driven by a driving roller and a driven roller. In addition, a plate-like support base that supports the transport belt is provided on the suction side of the transport belt between the driving roller and the driven roller so that the transport belt does not loosen, and the transport belt slides on the support base. (See FIG. 2 of Patent Document 1).

JP 2002-166213 A

  However, this liquid coating apparatus has a problem that the suction hole formed in the transport belt is large, the thin film sinks into the suction hole by the suction force, and the thin film is deformed into a crater shape.

  Further, since the conveying belt slides and moves while being attracted to the plate-like support table by the suction force for making the suction hole have a negative pressure, there is a problem that the frictional resistance with the support table increases. . Further, the plate-like support base has a problem that the suction hole of the transport belt is blocked and the suction force to the thin film is reduced.

  Furthermore, in such a belt conveyor type liquid coating apparatus, there is a problem that the meandering of the conveyor belt occurs. In this liquid coating apparatus, since the thin film is adsorbed and conveyed by the conveyance belt, the meandering of the conveyance belt has a great influence on the deformation of the thin film. In addition, as described above, there is a problem that meandering of the conveyor belt is promoted by the frictional resistance between the conveyor belt and the support base.

  Considering the case where an electrode catalyst layer is formed on an electrolyte membrane of a fuel cell using this conventional liquid coating apparatus, the deformation of the thin film, that is, the electrolyte membrane, causes non-uniformity in the performance of the fuel cell and the fuel cell itself. The performance will be greatly affected.

In the reference example, that provides an electrode catalyst layer for the fuel cell to reduce the deformation of the electrolyte membranes. In particular, that provides an electrode catalyst layer for the fuel cell to reduce the suction deformation of the electrolyte membrane by the suction holes.

  It is another object of the present invention to provide an electrode catalyst layer forming apparatus for a fuel cell, which has a low frictional resistance while maintaining a suction force and has an improved support mechanism for a conveyor belt.

  It is another object of the present invention to provide an electrode catalyst layer forming apparatus for a fuel cell that compensates for meandering of a conveyor belt.

  An electrode catalyst layer forming device for a fuel cell according to the present invention is an electrode catalyst layer forming device for a fuel cell that forms an electrode catalyst layer on an electrolyte membrane, and a coating means for applying a solution carrying a catalyst to the electrolyte membrane, And a conveying means for conveying the electrolyte membrane while sucking the electrolyte membrane by the suction holes of the conveying belt, and having the electrolyte membrane placed on the conveying belt having the suction hole formed thereon The cross-sectional area of the suction hole on the front side is smaller than the cross-sectional area of the suction hole on the back side of the conveyance belt on the suction side.

  An electrode catalyst layer forming device for a fuel cell according to the present invention is an electrode catalyst layer forming device for a fuel cell that forms an electrode catalyst layer on an electrolyte membrane, and a coating means for applying a solution carrying a catalyst to the electrolyte membrane, An electrolyte membrane is placed on the conveyor belt in which the suction holes are formed, and the electrolyte membrane is transported while being sucked by the suction holes of the conveyor belt, and the conveyor means is disposed on the back side of the conveyor belt. And having a plurality of backup rollers for supporting the conveyor belt.

  Further, in the fuel cell electrode catalyst layer forming apparatus of the present invention, the backup roller is configured as a backup roller unit in units of several, and at least one unit can be changed in arrangement posture. .

  Furthermore, the electrode catalyst layer forming apparatus for a fuel cell according to the present invention includes a meandering detector that detects meandering of the conveyor belt, and the backup roller unit changes the arrangement posture based on the detection of the meandering detector. And

  As described above, according to the present invention, the suction deformation of the electrolyte membrane due to the suction holes of the transport belt can be reduced.

  Further, according to the present invention, the conveying belt can be conveyed while reducing the frictional resistance while maintaining the suction force.

  Furthermore, according to the present invention, meandering of the conveyor belt can be easily corrected.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments (hereinafter referred to as embodiments) of the invention will be described with reference to the drawings. FIG. 1 is a configuration diagram showing an outline of the configuration of an electrode catalyst layer forming apparatus 10 (hereinafter referred to as an electrode catalyst layer forming apparatus 10) of a fuel cell according to this embodiment, and FIG. 2 is an electrode catalyst layer according to this embodiment. It is sectional drawing which shows typically the single-sided catalyst layer forming apparatus 12 with which the forming apparatus 10 is provided. The electrode catalyst layer forming apparatus 10 applies a solution carrying a catalyst to be an electrode catalyst layer (hereinafter referred to as a catalyst layer) that promotes an electrode reaction on both surfaces of an electrolyte membrane. The electrolyte membrane on which the catalyst layer is formed is used as a power generation layer of a polymer fuel cell.

  As shown in FIG. 1, the electrode catalyst layer forming apparatus 10 applies a solution 92 to the surface of an electrolyte membrane 90, and forms a catalyst layer 94 (see FIG. 2). And another one-side catalyst layer forming device 14 which is disposed in the rear stage of the device 12 and applies the solution 92 on the back surface to form the catalyst layer 94. The electrolyte membrane 90 is supplied from the roll 16, and after the solution 92 is applied by a spray coater provided at a predetermined position of the single-side catalyst layer forming apparatuses 12, 14 and the catalyst layer 94 is formed on both sides, Collected. The electrode catalyst layer forming apparatus 10 is provided with tension rolls 20 and 22 for applying a slight tension so as to be supplied to the single-side catalyst layer forming apparatuses 12 and 14 and the roll 18 with the electrolyte membrane 90 stretched. It has been.

  In this embodiment, the electrolyte membrane 90 is formed to a thickness of about 10 to 300 μm using a polymer material that exhibits good proton conductivity in a wet state, for example, perfluorosulfonate ionomer (trade name “Nafion” manufactured by DuPont). Is used. The solution 92 is prepared by dispersing carbon powder carrying a catalyst made of platinum or an alloy of platinum and another metal in ethanol, applied to the electrolyte membrane 90 by spraying with a spray coater, and dried to form a catalyst layer. 94 is formed.

  As shown in FIG. 2, the single-sided catalyst layer forming apparatus 12 includes a transporter 24 that circulates and transports the electrolyte membrane 90 in a U-shape, and a spray that applies a solution 92 to the surface of the transported electrolyte membrane 90 by spraying. The applicator 26 includes an upper drying duct 28 and a lower drying duct 30 that promote drying of the applied solution 92. In the embodiment, the application of the solution 92 by the spray applicator 26 is performed in four steps, and the spray applicator 26 and the upper drying duct 28 provided immediately after the application are set. The four stations are arranged continuously in the transport direction. Of course, the solution 92 may be applied only once, or divided into two, three, or five times. The lower drying duct 30 is disposed at a position (lower side in the figure) opposite to the position (upper side in the figure) of the spray applicator 26 with the position of the transport unit 24 as the center. That is, the lower drying duct 30 is formed as a linear duct extending in the conveying direction from the U-shaped folding position by the conveying device 24 after the spray coating device 26 is applied, and is applied to the electrolyte membrane 90. The solution 92 can be completely dried.

  Next, the conveyor 24 will be described in detail. FIG. 3 is an external view in which a portion of the transporter 24 is enlarged.

  As shown in FIGS. 2 and 3, the conveyor 24 includes a conveyor belt 34 on which an electrolyte membrane 90 is placed and a plurality of suction holes 32 are formed, a plurality of backup rollers 36 that support the conveyor belt 34, and a conveyor A driving roller 38 for moving the belt 34 and a driven roller 40 are provided. In the present embodiment, as shown in FIG. 3, a meandering detector 42 that detects meandering of the conveyor belt 34 is provided in the vicinity of the driving roller 38.

  As shown in FIG. 2, a plurality of backup rollers 36 are arranged on the upper path and the lower path of the conveying belt 34 between the driving roller 38 and the driven roller 40. A hollow space 44 is formed by a plurality of upper and lower backup rollers 36, and the space between the backup rollers (gap 46) is made negative by sucking the space 44 with a suction blower. As a result, a negative pressure is formed in the suction hole 32 of the conveyance belt 34 that moves on the backup roller 36. The electrolyte membrane 90 is sucked by the plurality of suction holes 32 of the transport belt and moves together with the transport belt 34.

  A characteristic point in this embodiment is that the suction holes 32 of the conveyor belt 34 are formed so that the electrolyte membrane 90 is not deformed by suction.

  FIG. 4 is a diagram illustrating a general example of the suction holes 96 of the transport belt 34. 4A and 4B, the left side is a plan view of the conveyor belt 34, the left side is a cross-sectional view, and FIG. 4C is a cross-sectional view only. The suction hole 96 is generally processed into a fine hole by an etching process. As shown in FIG. 4A, the suction holes 96 are formed to have a diameter φd, and the pitch L of the adjacent suction holes 96 is generally formed to be twice or more than φd in order to maintain the strength of the belt. Is done. However, if the diameter φd of the suction hole 96 is large, the difference in suction force between the suction part and the non-suction part becomes large, and the electrolyte membrane 90 cannot be sucked uniformly. It will sink into 96 and will deform | transform into a crater shape. Therefore, as shown in FIG. 4B, it is assumed that the suction hole 96 is formed with a large number of suction holes 96 by reducing the diameter φd of the suction holes 96 while keeping the pitch L of the suction holes 96 at least twice as large as φd. According to this, the difference in suction force between the suction part and the non-suction part by the suction hole 96 is reduced, and the electrolyte membrane 90 can be sucked uniformly. However, it is generally preferable that φd ≧ t in relation to the diameter φd of the suction hole 96 and the belt thickness t. Since the belt thickness t cannot be made very thin due to the strength against the belt tension, as shown in FIG. 4C, when the diameter φd of the suction hole 96 is reduced as described above, the suction path of the suction hole 96 becomes longer, and the vacuum Pressure loss, and the suction power decreases.

In the reference example , the cross-sectional area of the suction hole 32 on the front side of the transport belt 34 on the electrolyte membrane 90 mounting side is formed smaller than the cross-sectional area of the suction hole 32 on the back side of the transport belt 34 on the suction side. FIG. 5 is a view showing a cross section of the suction hole 32 of the reference example . As shown in FIG. 5, in the reference example , the suction hole 32 is processed from the mounting side of the electrolyte membrane 90 to a thickness t1 with a diameter φd1, and the suction side which is the opposite surface has a thickness φd2 which is larger than the diameter φd1. Process until t2. For example, φd1 = 0.15 mm, t1 = 0.15 mm, φd2 = 0.25 mm, t2 = 0.15 mm, and thickness t = 0.3 mm. In this case, the distance between the centers of adjacent suction holes is 0.3 mm. Accordingly, the suction hole 32 formed with the diameter φd1 can uniformly adsorb the electrolyte membrane 90 and prevent deformation due to suction. On the other hand, the suction force 32 can be prevented from being reduced by the suction hole 32 formed with the diameter φd2 which is the opposite surface. In this way, the cross-sectional area of the suction hole 32 on the mounting side of the electrolyte membrane 90 is reduced to suck the electrolyte membrane 90 uniformly, and the suction side on the opposite side is the suction hole on the mounting side of the electrolyte membrane 90. Since processing was performed with a cross-sectional area larger than 32, a reduction in suction force can be prevented. Thereby, it is possible to transport the electrolyte membrane 90 while preventing the deformation of the electrolyte membrane while maintaining the suction force of the suction holes of the transport belt 34.

In the reference example , suction paths are formed with different diameters on the electrolyte membrane placement side and suction side, but the diameter of the suction holes on the electrolyte membrane placement side is gradually increased toward the suction side. That is, the suction holes may be formed so as to expand in a tapered shape so that the cross-sectional area gradually increases.

  In addition, a characteristic point in the present embodiment is that a plurality of backup rollers 36 are arranged on the back side of the conveyance belt 34. When a vertical load is applied to the conveyor belt 34, a backup of the conveyor belt 34 is necessary. FIG. 6 is a view showing a general backup plate 98. In the example shown in FIG. 6, a plate-like backup plate 98 is placed to support the conveyor belt 34, a negative pressure is applied between the backup plates 98, and the conveyor belt 34 is attracted to the backup plate 98 side. Slid on the backup plate 98. Thus, since the conveyance belt 34 is attracted to the backup plate 98, there exists a problem that frictional resistance will become large. Further, as shown in FIG. 6, there is a problem that the surface of the backup plate 98 blocks the suction hole 32 and the suction force is reduced.

  Therefore, in the present embodiment, a plurality of backup rollers 36 are disposed on the back side of the conveyor belt 34. FIG. 7 is an external perspective view showing the backup roller 36 of the present embodiment, and FIG. 8 is a schematic sectional view. In FIG. 7, a similar backup roller 36 is also disposed in the lower conveyance path where the conveyance belt 34 is folded back, but is omitted in FIG. The plurality of backup rollers 36 are rotated by the movement of the conveyor belt 34. Thereby, when the transport belt 34 is moved, the frictional resistance between the transport belt 34 and the backup roller 36 is reduced. Further, as shown in FIG. 8, the contact area between each backup roller 36 and the conveyor belt 34 becomes small, so that the suction holes 32 of the conveyor belt 34 can be blocked. Thereby, the suction force of the suction hole 32 can be maintained.

  It is preferable that the diameter of the backup roller 36 is reduced and the gap between the backup rollers 36 is made as small as possible. For example, the length of the backup roller 36 is 350 mm, and its diameter φd is 16 mm.

  In this backup roller 36, since the bending rigidity strength per backup roller is taken into consideration, when sucked at 50 Kpa, the deflection at the central portion of the backup roller 36 can be suppressed to within 0.05 mm. The distance L between the centers of the two backup rollers 36 is 16.5 mm, in other words, the gap G between the outermost circumferences of the backup rollers 36 is 0.5 mm. When the backup roller 36 is viewed from above, the gap ratio formed by the gap G is preferably equal to or higher than the opening ratio of the suction holes 32. Thereby, it can prevent that attraction | suction force falls. Thereby, it is possible to convey the electrolyte membrane while preventing the sinking of the conveyor belt while uniformly sucking the electrolyte membrane.

  Returning to FIG. 1, the backup roller 36 is preferably configured as a backup roller unit 48 in units of several. A plurality of backup roller units 48 are combined and unitized in a state where each backup roller 36 is rotatable in accordance with the movement of the conveyor belt 34. The backup roller unit 48 preferably has several backup rollers 36 that are longer than the width w of the conveyor belt 34 and more preferably two to three times the width w of the conveyor belt 34. It is preferable to configure as a unit. In order for such a backup roller unit 48 to support the transport belt 34, a plurality of units are provided along the transport path of the transport belt 34. Note that the number of backup rollers 36 in one unit of the backup roller unit 48 may be the same or different.

  Furthermore, it is preferable that at least one of the backup roller units 48 is configured as a meandering correction backup roller unit 50 whose arrangement posture can be changed in order to compensate the meandering of the conveying belt 34. As shown in FIG. 1, the meandering correction backup roller unit 50 is disposed at a position adjacent to the drive roller 38 or the driven roller 40 on the entry side of the transport belt 34, and an adjustment unit 52 is provided on the side surface thereof. . By adjusting the adjusting unit 52, the meandering correction backup roller unit 50 is shifted up and down and left and right, and the parallel adjustment of the transport belt 34 can be performed.

  For example, as shown in FIG. 3, one bearing rail 50a of the backup roller 36 of the backup roller unit 50 is fixed to the substrate of the transport device, and the connecting portion 52a of the adjusting portion 52 is connected to the other bearing rail 50b. The motor 52b of the adjusting unit 52 is driven, and the connecting unit 52a is moved left and right with a ball screw or the like. As a result, the other bearing 50b moves to the left and right, and the axis of the backup roller 36 can be tilted to adjust the conveyance belt 34 in parallel.

  FIG. 9 is a diagram illustrating a specific example of parallel adjustment of the transport belt 34. In FIG. 9, the three backup rollers 36 constitute the backup roller unit 50 as one unit. Depending on the meandering amount and meandering direction of the conveying belt 34, adjustment is performed by moving it toward the driving roller 38 as shown in FIG. 9A or by moving away from the driving roller 38 as shown in FIG. 9B. Can do. In this manner, parallel adjustment is easier than adjusting the backup rollers 36 one by one with the meandering correction backup roller unit 50 in which the backup rollers 36 are unitized.

  In the present embodiment, as described above, the conveyor 24 includes the meandering detector 42 that detects the meandering of the conveyor belt 34. The meander detector 42 detects meandering of the conveyor belt. Thus, the meandering of the transport belt 34 over time can be detected, and the meandering correction backup roller unit 50 can change the arrangement posture based on the detection value of the meandering detector 42. Thereby, the parallelism of the conveyance belt 34 can be easily maintained.

  The meandering detector 42 is connected to a computer, the compensation amount of the meandering correction backup roller unit 50 is calculated by the computer from the detection value of the meandering detector 42, and adjusted via the control circuit based on the compensation amount of this computer. It is also preferable to drive the motor 52b of the section 52. Thereby, the arrangement | positioning attitude | position of the meandering correction | amendment backup roller unit 50 can be changed automatically, and the parallelism of a conveyance belt can be maintained easily.

  The single-sided catalyst layer forming device 14 is configured to be the same as the single-sided catalyst layer forming device 12 in the previous stage, and is disposed substantially horizontally facing the single-sided catalyst layer forming device 12 as shown in FIG. Each configuration of the single-sided catalyst layer forming device 14 is the same as the configuration of the single-sided catalyst layer forming device 12 in the previous stage, and the same components are denoted by the same reference numerals and description thereof is omitted. . That is, the electrolyte membrane 90 having the catalyst layer 94 formed on the surface thereof by the preceding single-sided catalyst layer forming device 12 is supplied to the single-sided catalyst layer forming device 14 so that the catalyst layer 94 side is sucked by the suction holes 32 of the conveying belt 34. Is done. Thereby, the catalyst layer 94 can be formed on the back surface of the electrolyte membrane 90 as in the single-side catalyst layer forming apparatus 12. The coating and drying process in the single-sided catalyst layer forming apparatus 94 is performed in the same manner as the single-sided catalyst layer forming apparatus 12.

  The electrolyte membrane 90 having the catalyst layer 94 formed on both sides is collected by the roll 18.

  Next, the application | coating operation | movement of the solution 92 of the electrode catalyst layer forming apparatus 10 is demonstrated. First, the electrolyte membrane 90 supplied from the roll 16 is sucked from the back side of the electrolyte membrane 90 to the conveyor belt 34 of the single-sided catalyst layer forming apparatus 12 and started to be conveyed, and at the surface of the electrolyte membrane 90 by the spray coater 26. Solution 92 is applied. At this time, the electrolyte membrane 90 is wetted by the solution 92, but is quickly dried by the supply and exhaust of the upper drying duct 28. After the application and drying of the solution 92 are repeated by the four spray applicators 26 and the upper drying duct 28, the solution 92 is folded back into a U-shape and conveyed back. In the return conveyance, the electrolyte membrane 90 wetted by the solution 92 is completely dried by supplying and exhausting air from the lower drying duct 30. When the application by the single-side catalyst layer forming device 12 in the preceding stage is thus performed, the front side of the electrolyte membrane 90 (the surface applied by the single-side catalyst layer forming device 12 in the previous stage) is placed on the transport belt 34 of the single-side catalyst layer forming device 14 in the subsequent stage. The suction is started and the conveyance is started. The solution 92 is applied to the back surface of the electrolyte membrane 90 by the spray applicator 26. At this time, the electrolyte membrane 90 is dried by the upper drying duct 28 and the lower drying duct 30 as in the case of the one-side catalyst layer forming apparatus 12 in the previous stage. Thus, the solution 92 is applied to both surfaces of the electrolyte membrane 90, and the catalyst layer 94 is formed. It should be noted that the latter stage so that the catalyst layer 94 formed on the surface of the electrolyte membrane 90 by the one-side catalyst layer forming device 12 and the catalyst layer 94 formed on the rear surface of the electrolyte membrane 90 by the latter one-side catalyst layer forming device 14 are aligned. The application timing of the solution 92 by the spray applicator 26 of the one-side catalyst layer forming apparatus 14 is adjusted.

  In the present embodiment, the electrolyte membrane 90 is transported, but a thin film assembly in which a support film is attached to the electrolyte membrane disclosed in JP-A-2002-166213 may be transported. When this thin film assembly is conveyed, a mechanism for peeling the support film is provided before the electrolyte membrane is supplied to the subsequent single-sided catalyst layer forming apparatus.

  In the electrode catalyst layer forming apparatus 10, the solution 92 is applied to both surfaces of the electrolyte membrane 90, but the solution 92 may be applied only to the front surface or the back surface of the electrolyte membrane 90. In this case, a configuration without the subsequent single-sided catalyst layer forming device 14 may be used.

  Furthermore, in the present embodiment, it is preferable that a heater for heating the backup roller 36 is provided so that the transport belt 34 can be heated so that the electrolyte membrane 90 can be dried.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to these embodiment at all, and can be implemented with a various form in the range which does not deviate from the summary of this invention. Of course.

It is a block diagram which shows the outline of a structure of the electrode catalyst layer forming apparatus of the fuel cell of embodiment. It is sectional drawing which shows typically the single-sided catalyst layer forming apparatus with which the electrode catalyst layer forming apparatus of embodiment is equipped. It is the external view which expanded the part of the conveying machine. It is a figure which shows the general example of the suction hole of a conveyance belt. It is a figure which shows the cross section of the suction hole of a reference example . It is a figure which shows a general backup plate. It is an external appearance perspective view which shows the backup roller of embodiment. It is a schematic sectional drawing of the backup roller of embodiment. It is a figure which shows the specific example of the parallel adjustment of a conveyance belt.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Electrode catalyst layer forming apparatus, 12, 14 Single-sided catalyst layer forming apparatus, 16, 18 roll, 20, 22 Tension roll, 24 Transporter, 26 Spray coating machine, 28 Upper drying duct, 30 Lower drying duct, 32 Suction hole , 34 Conveyor belt, 36 Backup roller, 38 Drive roller, 40 Driven roller, 42 Meander detector, 44 Vacant chamber, 46 Gap, 48 Backup roller unit, 50 Meander correction backup roller unit, 52 Adjustment unit, 90 Electrolyte membrane, 92 Solution, 94 electrode catalyst layer, 96 suction holes, 98 backup plate.

Claims (1)

An electrode catalyst layer forming apparatus for a fuel cell that forms an electrode catalyst layer on an electrolyte membrane,
Application means for applying a solution containing carbon powder supporting a catalyst to the electrolyte membrane;
A transport means for placing the electrolyte membrane on a transport belt formed with a plurality of suction holes, and transporting the electrolyte membrane while sucking the electrolyte membrane through the suction holes of the transport belt;
A meander detector for detecting meandering of the conveyor belt ;
With
The conveying means is disposed on the back side of the conveying belt, and has a plurality of backup rollers that support the conveying belt,
The backup roller is configured as a backup roller unit having a plurality of cylindrical rollers having a width equal to or greater than the width of the conveyor belt, and at least one backup roller unit is based on detection by the meandering detector. An electrode catalyst layer forming apparatus for a fuel cell, wherein the arrangement posture is changed.

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