JP6926871B2 - Manufacturing method of membrane electrode assembly of fuel cell - Google Patents

Description

The present invention relates to a method for manufacturing a membrane electrode assembly of a fuel cell to which a label for identifying quality is attached.

Patent Document 1 discloses a technique of attaching an identification label to a continuous sheet when processing the continuous sheet. According to Patent Document 1, in the process of processing while unwinding a continuous sheet wound in a roll shape, when a quality defect occurs, a label for identifying the quality defect is attached before and after the position where the quality defect occurs. The affixed label identifies the defective part, accurately conveys the defective part to the next process, and removes the generated defective part by the final process.

Japanese Unexamined Patent Publication No. 2006-306509

It is envisioned that such a label that identifies individual information of a processed product will be used in a method for manufacturing a membrane electrode assembly of a fuel cell that processes a sheet wound in a roll shape. However, in the process of manufacturing a membrane electrode assembly of a fuel cell, the original sticking surface of the label is exposed in subsequent steps and instead the opposite side of the original sticking surface, i.e. the original label. The exposed surface may be the sticking surface. In this case, the initial sticking surface is exposed, and depending on the adhesive force of the initial sticking surface, the initial sticking surface is caught by the transport device in the subsequent transport process, and the label disappears. There is a risk.

The present invention has been made to solve such a problem, and is a fuel cell capable of preventing peeling of a label adhered to a component of a membrane electrode assembly and suppressing disappearance of a label in a manufacturing process. It is an object of the present invention to provide a method for producing a membrane electrode assembly.

The method for manufacturing a film electrode joint of a fuel cell according to the present invention includes a first transfer step of transporting a back sheet having a first member and a label on the surface, and heating the second member to the first member. A step of crimping and adhering the label to the second member, a step of peeling off the back sheet, and a second step of transporting the first member and the label provided on the surface of the second member. A thermoplastic resin is provided on the surface of the label that comes into contact with the second member, and the thermoplastic resin has a peeling force in the 180 ° direction from the opposite surface. Is characterized by high.

In the method for manufacturing a membrane electrode assembly of a fuel cell according to the present invention, in the first transport step before the step of adhering the label to the second member, the label is provided on the opposite side of the surface in contact with the back sheet of the label. The adhesive strength of the exposed thermoplastic resin is less than the adhesive strength of the label attached to the backsheet. As a result, in the first transfer step, the exposed thermoplastic resin of the label adheres to other components, thereby preventing the label from being peeled off from the back sheet and suppressing the disappearance of the label. ..

Then, after the step of adhering the label to the second member, the thermoplastic resin provided on the surface opposite to the surface in contact with the back sheet of the label and the second member are heat-bonded to form the label. It is adhered to the second member via a thermoplastic resin. This thermoplastic resin has a higher peeling force in the 180 ° direction than the surface opposite to the surface where the label is adhered to the second member (the surface where the label is adhered to the back sheet). As a result, even in the second transfer step, the label is prevented from adhering to other components and being peeled off from the second member, and the disappearance of the label is suppressed.

According to the present invention, a method for manufacturing a membrane electrode assembly of a fuel cell capable of preventing peeling of a label adhered to a component of the membrane electrode assembly and suppressing disappearance from the component of the label in the manufacturing process. Can be provided.

The figure of the membrane electrode assembly produced by the manufacturing method of the membrane electrode assembly of the fuel cell which concerns on embodiment of this invention. FIG. 3 is a cross-sectional view of a back sheet used in a method for manufacturing a membrane electrode assembly of a fuel cell according to an embodiment of the present invention. The figure of the label used in the manufacturing method of the membrane electrode assembly of the fuel cell which concerns on embodiment of this invention. The process drawing which shows the process of the manufacturing method of the membrane electrode assembly of the fuel cell which concerns on embodiment of this invention. The explanatory view which shows typically the transfer apparatus applied to the manufacturing method of the membrane electrode assembly of the fuel cell which concerns on embodiment of this invention.

A method for manufacturing the membrane electrode assembly 10 of the fuel cell according to the embodiment to which the method for manufacturing the membrane electrode assembly of the fuel cell according to the present invention is applied will be described with reference to the drawings. First, the configuration of the membrane electrode assembly 10 will be described.

As shown in FIGS. 1A and 1B, the membrane electrode assembly 10 according to the embodiment is composed of an anode junction 11 and a cathode catalyst layer 12 laminated on the anode junction 11. There is. A cathode side gas diffusion layer is laminated on the outside of the cathode catalyst layer 12 on the membrane electrode assembly 10.

Further, a pair of separators and gaskets are incorporated in the membrane electrode assembly 10 to form a fuel cell. A plurality of these fuel cell cells are stacked and stacked to form a fuel cell (not shown). The cathode catalyst layer 12 corresponds to the first member in the method for manufacturing a membrane electrode assembly of a fuel cell according to the present invention, and the anode junction 11 corresponds to the method for manufacturing a membrane electrode assembly for a fuel cell according to the present invention. Corresponds to the second member.

The anode junction 11 is composed of an electrolyte membrane (not shown), an anode catalyst layer (not shown) formed on one surface of the electrolyte membrane, and an anode-side gas diffusion layer (not shown) formed outside the anode catalyst layer. There is. The electrolyte membrane, the anode catalyst layer, and the anode-side gas diffusion layer are laminated and integrated into a bonded body.

The electrolyte membrane is formed of a fluorine-based electrolyte resin, and is composed of an ion exchange membrane using a polymer membrane having ionic conductivity as an electrolyte. The electrolyte membrane has a function of blocking the flow of electrons and gas and moving protons from the anode catalyst layer to the cathode catalyst layer 12.

The anode catalyst layer is made of a conductive carrier carrying a catalyst such as platinum or a platinum alloy, and is formed from an electrode catalyst layer formed by coating carbon particles such as catalyst-supported carbon particles with an ionomer having proton conductivity. Become. The ionomer is made of a polyelectrolyte resin which is a solid polymer material such as a fluororesin, and has proton conductivity due to its ion exchange group. The anode catalyst layer has a function of decomposing hydrogen gas into protons and electrons.

The anode-side gas diffusion layer is formed of a gas-permeable and conductive material, for example, a carbon fiber such as carbon paper or a porous fiber base material such as graphite fiber. The anode-side gas diffusion layer has a function of diffusing hydrogen (H) gas to make it uniform and spreading it to the anode catalyst layer.

The cathode catalyst layer 12 is made of the same material as the anode catalyst layer, but unlike the anode catalyst layer, it has a function of generating water from protons, electrons, and oxygen. As shown in FIGS. 2A to 2C, the cathode catalyst layer 12 is formed intermittently by intermittent coating in which the surface of the backsheet BS is intermittently coated with the cathode catalyst ink. The intermittent cathode catalyst layer 12 formed on the surface of the backsheet BS is transferred to the anode junction 11, and is intermittently transferred to the surface of the anode junction 11 as shown in FIGS. 1 (a) and 1 (b). A membrane electrode assembly 10 on which the cathode catalyst layer 12 is laminated is formed.

In the method for manufacturing the membrane electrode assembly 10 of the fuel cell according to the embodiment, when some quality defect occurs in the cathode catalyst layer 12 and the back sheet, it is the surface of the back sheet BS shown in FIG. 2 (a). Therefore, the label L is adhered to the gap C in which the cathode catalyst layer 12 is not formed between the intermittently formed cathode catalyst layer 12 and the cathode catalyst layer 12 adjacent thereto.

The label L may be adhered not only to the gap C but also to the surface of the cathode catalyst layer 12 as shown in FIG. 2 (b). Further, as shown in FIG. 2C, the label L straddles between the surface of the cathode catalyst layer 12 and the gap C, a part thereof is adhered to the surface of the cathode catalyst layer 12, and the other part is a gap. It may protrude to C and be adhered to the back sheet.

When the label is adhered to the surface of the cathode catalyst layer 12 as shown in FIG. 2 (b), the label L is the anode junction 11 and the cathode catalyst layer 12 as shown in FIG. 1 (c). The membrane electrode assembly 10 is formed in a state of being sandwiched between the two. Further, when the label L is adhered so as to straddle the surface of the cathode catalyst layer 12 and the gap C as shown in FIG. 2C, one of the labels L is attached as shown in FIG. 1D. The membrane electrode assembly 10 is formed with the portion exposed in the gap C.

In the method for manufacturing the membrane electrode assembly 10 of the fuel cell according to the embodiment, the label L will be described with a configuration in which the label L is adhered to the gap C shown in FIG. 2A for convenience. Even when the label L is bonded at the bonding position shown in FIG. 2 (b) or the bonding position shown in FIG. 2 (c), the label L is bonded to the gap C shown in FIG. 2 (a). Similarly, the membrane electrode assembly 10 of the fuel cell according to the embodiment is produced, and the same effect can be obtained in each case.

The label L has a label base material made of a heat-resistant synthetic resin film, and as shown in FIG. 3, has an adhesive surface La coated with an acrylic resin adhesive on one surface. The other surface has a resin surface Lp coated with a thermoplastic resin. The resin surface Lp of the label L corresponds to the surface in contact with the second member of the label in the method for manufacturing a membrane electrode assembly of a fuel cell according to the present invention. Further, the adhesive surface La of the label L corresponds to the opposite surface in the method for manufacturing a membrane electrode assembly of a fuel cell according to the present invention.

Before the cathode catalyst layer 12 is transferred to the anode junction 11, the label L has an adhesive surface La adhered to the surface of the backsheet BS as shown in FIG. 2A, and the resin surface Lp is exposed. It is in a state of being. When the cathode catalyst layer 12 is transferred to the anode junction 11, the label L is in a state where the resin surface Lp is adhered to the surface of the anode junction 11 on the cathode catalyst layer 12 side.

The acrylic resin adhesive formed on the adhesive surface La of the label L has adhesiveness, and the label L can be adhered to the back sheet BS. When the label L is transferred to the anode junction 11, the thermoplastic resin coated on the resin surface Lp of the label L is melted by heating and pressurizing during the transfer, and the label L is adhered to the anode junction 11. Can be done. The thermoplastic resin is made of a thermoplastic resin such as an ethylene-vinyl acetate copolymer resin (EVA), a polypropylene resin (PP), or a polyamide resin (PA).

Next, a method of manufacturing the membrane electrode assembly 10 of the fuel cell according to the embodiment will be described with reference to the drawings.

As shown in FIG. 4, the method for manufacturing the membrane electrode assembly 10 of the fuel cell according to the present embodiment includes a first transport step, an adhesion step, a cooling step, a peeling step, and a second transport step. Is configured to include. Each of these steps is performed sequentially. The bonding step corresponds to the step of heat-bonding the second member to the first member and bonding the label to the second member in the method for manufacturing a membrane electrode assembly of a fuel cell according to the present invention. The peeling step corresponds to the step of peeling the back sheet. Further, the first transfer step, the bonding step, the peeling step, and the second transfer step of the present embodiment constitute the method for manufacturing the membrane electrode assembly of the fuel cell according to the present invention.

In the first transfer step, as shown in FIG. 5, the backsheet BS having the cathode catalyst layer 12 intermittently formed on the surface is conveyed by a transfer device (not shown) (step S1). A label L is attached to the gap C between the adjacent cathode catalyst layer 12. The adhesive surface La of the label L is adhered to the back sheet BS.

In the bonding step, the anode catalyst layer 11 is heated and pressurized by the pair of transfer rolls 20 shown in FIG. 5 with respect to the cathode catalyst layer 12 of the conveyed backsheet BS, and the cathode catalyst layer 12 is heated and pressurized while being conveyed. Is transferred to the anode junction 11. That is, the anode junction 11 is adhered to the cathode catalyst layer 12 by thermal pressure bonding. Along with this transfer, the thermoplastic resin coated on the resin surface Lp of the label L of the back sheet BS is melted, and the resin surface Lp of the label L is adhered to the anode joint 11 (step S2).

In the bonding step, a laminate S in which the cathode catalyst layer 12, the backsheet BS, the label L, and the anode junction 11 are integrated is formed, and is sent out by the transfer roll 20.

In the cooling step, the laminated body S that has been transferred and sent out from the pair of transfer rolls 20 is cooled by the cooling roll 30 (step S3). That is, heat exchange is performed between the laminated body S and the cooling roll 30, and the temperature (° C.) of the laminated body S drops.

By cooling with the cooling roll 30, the thermoplastic resin coated on the resin surface Lp of the label L is cured, and the label L is strongly adhered to the anode joint 11. The cooled laminate S is sent out by the cooling roll 30.

In the peeling step, the back sheet BS is peeled off by the peeling roll 40 from the laminated body S which has been cooled and sent out by the cooling roll 30 (step S4). The peeled back sheet BS is wound by a winding mechanism (not shown) via the roll 50.

In the second transfer step, the back sheet BS is peeled off from the laminated body S, and the membrane electrode assembly 10 composed of the anode junction 11 and the cathode catalyst layer 12 to which the label L is adhered is pressed by the free roll 60. , For example, the step of forming the cathode side gas diffusion layer on the outside of the cathode catalyst layer 12 (step S5).

According to the method for manufacturing the membrane electrode assembly 10 of the fuel cell according to the present embodiment, the adhesive force of the resin surface Lp can be increased more than the adhesive force of the adhesive surface La by utilizing the heat of the adhesive process. .. That is, the heat generated when the cathode catalyst layer 12 is heat-bonded to the anode junction 11 is used to switch the adhesive force between the adhesive surface La and the resin surface Lp, and the adhesive force of the adhesive surface La is used as the resin surface before the bonding process. The adhesive strength of the resin surface Lp can be made higher than the adhesive strength of the adhesive surface La after the bonding step.

Therefore, the label L can be transferred so as to adhere to the anode junction 11 with a force exceeding the adhesive force of the adhesive surface La, and even if the membrane electrode assembly 10 is conveyed with the adhesive surface La exposed, the heat of the resin surface Lp Since the plastic resin is strongly adhered to the anode junction 11, the label L does not adhere to equipment such as the free roll 60, and the label can be prevented from disappearing.

Hereinafter, the method for manufacturing the membrane electrode assembly of the fuel cell according to the present invention will be described according to Examples 1 to 3 and Comparative Example of the membrane electrode assembly 10 in the method for manufacturing the membrane electrode assembly 10 of the fuel cell according to the present embodiment. This will be described in more detail. However, the technical scope of the method for manufacturing a membrane electrode assembly of a fuel cell according to the present invention is not limited to Examples 1 to 3.

<Example 1>
The electrolyte membrane constituting the anode junction 11 was formed of a fluorine-based electrolyte membrane, and the anode catalyst layer constituting the anode junction 11 was formed of platinum-supported carbon. Further, the anode-side gas diffusion layer constituting the anode junction 11 was formed of carbon paper. The anode catalyst layer and the anode side gas diffusion layer were transferred to the electrolyte membrane, and the electrolyte membrane, the anode catalyst layer and the anode side gas diffusion layer were sequentially laminated and integrated to prepare an anode junction 11.

The backsheet BS was made of a fluororesin film. A cathode catalyst layer 12 made of platinum-supported carbon was intermittently formed on the produced backsheet BS by intermittent coating. A label L was prepared using a heat-resistant synthetic resin film as a label base material. The size of the label L was appropriately selected in the range of width 100 mm to 500 mm and length 100 mm to 500 mm.

The label L is formed by applying an acrylic resin adhesive to one surface of the label substrate to form an adhesive surface La, and coating the other surface of the label substrate with an ethylene-vinyl acetate copolymer resin (EVA). A resin surface Lp was formed. Then, as shown in FIG. 2A, the adhesive surface La of the label L was adhered to the surface of the gap C where the cathode catalyst layer 12 was missing on the surface where the cathode catalyst layer 12 of the backsheet BS was formed. .. The resin surface Lp of the label L is exposed in the gap C.

As shown in FIG. 5, the back sheet BS on which the cathode catalyst layer 12 is formed and the label L is adhered and the anode junction 11 are drawn into the transfer roll 20 and heated and pressurized while being conveyed to bring the cathode catalyst layer 12 together. Transferred to the anode junction 11. The transfer speed by the transfer roll 20 was set to 1 m / min to 10 m / min, the heating temperature was set to 100 ° C to 180 ° C, and the transfer pressure was set to 2 kN to 8 kN. The label L was adhered to the anode junction 11 by transfer.

The transfer roll 20 sends out the laminate S in which the back sheet BS on which the cathode catalyst layer 12 is formed and the label L is adhered and the anode junction 11 are integrated, and each component of the laminate S is cooled by the cooling roll 30. Cooled with. The temperature (° C.) of the cooling roll 30 was set to 10 ° C. to 40 ° C. By cooling, the ethylene-vinyl acetate copolymer resin (EVA) coated on the resin surface Lp of the label L was cured, and the label L was strongly adhered to the anode junction 11.

The backsheet BS was peeled off from the laminated body S sent out from the cooling roll 30 by the peeling roll 40 to prepare the membrane electrode assembly 10 according to Example 1. A predetermined quantity of the membrane electrode assembly 10 according to Example 1 was produced by the same step.

<Example 2>
The anode junction 11 and the backsheet BS were produced in the same manner as in Example 1, and the cathode catalyst layer 12 was formed on the backsheet BS by intermittent coating. In the label L according to Example 2, a heat-resistant synthetic resin film is used as a label base material, and an acrylic resin adhesive is applied to one surface of the label base material to form an adhesive surface La, which is a label base material. The other surface was coated with a polypropylene resin (PP) to form a resin surface Lp. Next, each component was processed in the same manner as in Example 1 to prepare the membrane electrode assembly 10 according to Example 2. A predetermined quantity of the membrane electrode assembly 10 according to Example 2 was also produced by the same step.

<Example 3>
The anode junction 11 and the backsheet BS were produced in the same manner as in Example 1, and the cathode catalyst layer 12 was formed on the backsheet BS by intermittent coating. In the label L according to Example 3, a heat-resistant synthetic resin film is used as a label base material, and an acrylic resin adhesive is applied to one surface of the label base material to form an adhesive surface La, which is a label base material. The other surface was coated with a polyamide resin (PA) to form a resin surface Lp. Next, each component was processed in the same manner as in Example 1 to prepare the membrane electrode assembly 10 according to Example 3. A predetermined quantity of the membrane electrode assembly 10 according to Example 3 was also produced by the same step.

<Comparison example>
The anode junction 11 and the backsheet BS were produced in the same manner as in Example 1, and the cathode catalyst layer 12 was formed on the backsheet BS by intermittent coating. For the label L according to the comparative example, a heat-resistant paper film was used as the label base material, and an acrylic resin adhesive was applied to one surface of the label base material to form an adhesive surface La. The label L according to the comparative example is different from Examples 1 to 3, and the other surface of the label base material is not coated. That is, in the label L according to the comparative example, the non-adhesive paper film is exposed as it is on the surface corresponding to the resin surface Lp of Examples 1 to 3, that is, the surface opposite to the adhesive surface La, and is adhesive. Does not have. Next, each component was processed in the same manner as in Example 1 to prepare a membrane electrode assembly 10 according to a comparative example. A predetermined quantity of the membrane electrode assembly 10 according to the comparative example was also produced by the same step.

<Evaluation of Examples and Comparative Examples>
With respect to the predetermined number of membrane electrode assemblies 10 produced in Examples 1 to 3 and Comparative Examples, the peeling force (N / cm) for peeling the label L on which the adhesive surface La is adhered to the backsheet BS from the backsheet BS. ) Was measured. The peeling force in the 180 ° direction was measured with the angle at which the label L was peeled from the backsheet BS as 180 °. The peeling force in the 180 ° direction was measured by using a 180 ° peeling tester.

Further, a peel strength test in the 180 ° direction was performed by using a 180 ° peel tester so as to measure the peeling force of the resin surface Lp of the label L. Further, with respect to the total number of the predetermined quantities of Examples 1 to 3 and Comparative Example, the label L is peeled off from the anode assembly 11 and disappears between the time when the label L is adhered and the time when the membrane electrode assembly 10 is completed. The ratio (%) of the quantity of the label L to the total number of attached labels was calculated.

The peeling force (N / cm) represents the magnitude of the resistance force generated when the label L is peeled off. The larger the peeling force, the larger the adhesive force, and the peeling force and the adhesive force are in a proportional relationship. It is in. The measurement results of Examples 1 to 3 and Comparative Examples are shown in Table 1 below.

The item shown in Table 1, the peeling force in the 180 ° direction of the acrylic resin, represents the peeling force for peeling the label L from the backsheet BS in the 180 ° direction in a state where the adhesive surface La of the label L is adhered to the backsheet BS. ing. The item shown in Table 1, the peeling force in the 180 ° direction of the thermoplastic resin, is the peeling force for peeling the label L from the anode joint 11 in the 180 ° direction while the resin surface Lp of the label L is adhered to the anode joint 11. Represents.

(Evaluation of Example 1)
As shown in Table 1, the membrane electrode assembly 10 of Example 1 has an acrylic resin 180 ° direction peeling force of 48 N / cm and a thermoplastic resin 180 ° direction peeling force of 71 N / cm. Therefore, the adhesive force of the resin surface Lp of the label L is extremely larger than the adhesive force of the adhesive surface La of the label L, and the adhesive force of the adhesive surface La of the label L <the adhesive force of the resin surface Lp of the label L. It can be evaluated that the label L is not peeled off when the film electrode bonded body 10 is manufactured.

Actually, as shown in Table 1, the ratio of the disappearing label to the total number of labels attached is 0%, and in the method for manufacturing the membrane electrode assembly 10 of the fuel cell according to the first embodiment of the present embodiment, the ratio of the disappearing label is 0%. The effect that the disappearance of the label L from the anode junction 11 can be suppressed can be obtained.

(Evaluation of Examples 2 and 3)
As shown in Table 1, the membrane electrode assembly 10 of Examples 2 and 3 has an acrylic resin 180 ° direction peeling force of 48 N / cm and a thermoplastic resin 180 ° direction peeling force of 78 N / cm. There is. Therefore, in Examples 2 and 3, similarly to Example 1, the adhesive force of the resin surface Lp of the label L is much larger than the adhesive force of the adhesive surface La of the label L, and the adhesive force of the adhesive surface La of the label L is adhered. It can be evaluated that the force <the adhesive force of the resin surface Lp of the label L, and the label L is not peeled off when the film electrode joint 10 is manufactured.

Actually, as shown in Table 1, the ratio of the disappearing label to the total number of labels attached is 0%, and in the method for manufacturing the membrane electrode assembly 10 of the fuel cell according to Examples 2 and 3 of the present embodiment. Has the effect of suppressing the disappearance of the label L from the anode assembly 11.

(Evaluation of comparative example)
As shown in Table 1, the membrane electrode assembly 10 of the comparative example has an acrylic resin 180 ° direction peeling force of 48 N / cm and a thermoplastic resin 180 ° direction peeling force of 0 N / cm. In the label L of the comparative example, the surface corresponding to the resin surface Lp of Examples 1 to 3 is not imparted with adhesive force, and the label base material (paper film) of the label L is exposed as it is. There is. Therefore, it is evaluated that the adhesive strength of the adhesive surface La of the label L> the adhesive strength of the base material of the label L, and the risk of the label L being peeled off is high when the membrane electrode assembly 10 is manufactured. Can be done.

Actually, as shown in Table 1, the ratio of the disappearing label to the total number of labels attached is 20%, and in the method for manufacturing the membrane electrode assembly 10 of the fuel cell according to the comparative example of the present embodiment, the label is used. The effect that the disappearance of L from the anode junction 11 can be suppressed cannot be obtained.

Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and various designs are designed without departing from the spirit of the present invention described in the claims. You can make changes.

10 ... Membrane electrode assembly, 11 ... Anode junction (second member), 12 ... Cathode catalyst layer (first member), 20 ... Transfer roll, 30 ... Cooling roll , 40 ... peeling roll, 50 ... roll, 60 ... free roll, BS ... back sheet, L ... label, La ... adhesive surface (opposite surface), Lp ... -Resin surface (surface that comes into contact with the second member)

Claims (1)

A method for manufacturing a membrane electrode assembly of a fuel cell.
The first transfer step of transporting the back sheet having the cathode catalyst layer and the label on the surface, and
A step of heat-bonding the anode joint to the cathode catalyst layer and adhering the label to the anode joint.
A step of cooling the laminate formed by the step of bonding and
The process of peeling off the back sheet and
The cathode catalyst layer provided on the surface of the anode joint and the second transport step of transporting the label are provided.
A thermoplastic resin is provided on the surface of the label in contact with the anode assembly, and the thermoplastic resin has a higher peeling force in the 180 ° direction than the surface on the opposite side. Method for manufacturing a membrane electrode assembly.

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