JP2015095349A - Method for manufacturing electrolyte membrane structure - Google Patents

Abstract

There is room for improvement in reducing manufacturing defects of electrolyte membranes. A reinforcing membrane is impregnated from a predetermined surface of each of two electrolyte single membranes to produce an intermediate impregnation membrane. The intermediate impregnation films 40 are bonded to each other on a predetermined surface to form the impregnation film 50. The predetermined surface is a surface impregnated with the reinforcing film 30. [Selection] Figure 2

Description

  The present invention relates to an electrolyte membrane.

  In the manufacturing process of the electrolyte membrane structure, a technique is known in which the electrolyte membrane is bonded from both sides of the porous reinforcing membrane and the electrolyte membrane is impregnated with the porous reinforcing membrane (for example, Patent Document 1).

JP 2009-283448 A

  The subject which the said prior art has is that there exists room for improvement about reducing the manufacturing defect of an electrolyte membrane structure. In addition, downsizing of the apparatus, cost reduction, resource saving, ease of manufacture, improvement in usability, and the like have been desired.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms.

  According to one form of this invention, the manufacturing method of electrolyte membrane structure is provided. The manufacturing method includes a step of impregnating a porous reinforcing membrane from a predetermined surface of the electrolyte single membrane; and a step of bonding the impregnated electrolyte single membranes to each other on the predetermined surface. According to this embodiment, manufacturing defects due to air being enclosed in the impregnation step are reduced. Even in the case of manufacturing an electrolyte membrane structure by impregnating two electrolyte membranes with a porous reinforcing membrane as in this embodiment, air is discharged from one side of the porous reinforcing membrane in the impregnation step. It is.

Process drawing which shows the manufacturing method of MEGA. The figure which shows the manufacturing method of an intermediate | middle impregnation film | membrane and an impregnation film | membrane. The figure which shows preparation of the impregnation film | membrane in the comparative example 1. FIG. The figure which shows preparation of the impregnation film | membrane in the comparative example 2. FIG. The figure which shows the reinforcing bar exposed to the surface of electrolyte membrane.

FIG. 1 is a process diagram showing a manufacturing method of MEGA (Membrane Electrode & Gas diffusion layer assembly) in the present embodiment. First, the electrolyte single film 20 is produced (step S100). Specifically, it is produced by extruding a precursor polymer resin of an electrolyte resin. The precursor polymer resin has a polymer chain terminal of —SO ₂ F and an ion exchange capacity (IEC) of 1.54 meq / g. The thickness of the electrolyte single membrane 20 is about 3 μm.

  Next, the reinforcing film 30 is produced (step S200). Specifically, the raw tape is produced by drawing with a simultaneous biaxial drawing machine and further firing. The raw tape is produced by subjecting PTFE fine powder to paste extrusion and rolling. The reinforcing membrane 30 in this embodiment has a thickness of about 4 μm and is porous (porosity is 40 to 60%).

  Subsequently, the intermediate impregnated film 40 is produced (step S300). FIG. 2 is a diagram showing a method for manufacturing the intermediate impregnation film 40 and an impregnation film 50 described later. The intermediate impregnation film 40 is produced by bonding the electrolyte single film 20 produced in Steps S100 and 200 and the reinforcing film 30 together. This bonding is realized by hot pressing using a heating roller 90. Specific conditions are a temperature of 250 ° C., a surface pressure of 0.5 MPa, and a conveyance speed of 0.1 m / min.

  Subsequently, the impregnated film 50 is produced (step S400). Specifically, the two intermediate impregnated films 40 are bonded together by hot pressing using the heating roller 90. The conditions for hot pressing are the same as above. This bonding is performed by bringing predetermined surfaces of the intermediate impregnation film 40 into contact with each other. As shown in FIG. 2, the predetermined surface is a surface that has been in contact with the reinforcing film 30 in Step S <b> 200, that is, a surface that has become an entrance for impregnation.

Subsequently, an electrolyte membrane is produced (step S500). The specific procedure is as follows. First, the impregnated film 50 is hydrolyzed with an aqueous sodium hydroxide solution. This aqueous solution has a concentration of 9 mol / l and a temperature of 80 ° C. Next, it is washed with pure water, and the end of the polymer chain is replaced with an acid type (—SO ₃ H) with an aqueous nitric acid solution. This aqueous solution has a concentration of 1 mol / l and a temperature of 80 ° C. The electrolyte membrane is manufactured by washing again with pure water and then drying.

  Finally, MEGA is manufactured (step S600). Specifically, it is prepared by forming a CCM (Catalyst Coated Membrane) by a transfer method and then sandwiching the CCM by two GDLs (Gas Diffusion Layer). The conditions for the transfer method are a temperature of 130 ° C., a surface pressure of 4 MPa, and a time of 4 minutes.

  FIG. 3 is a diagram showing the production of the impregnated film 51 in Comparative Example 1. As shown in FIG. 3, the impregnated film 51 is manufactured by disposing the reinforcing film 30 on both sides of the electrolyte single film 20 and performing hot pressing. However, unlike the embodiment, the thickness of the electrolyte single membrane 20 is about 6 μm, and the conveyance speed in the hot press is 0.05 m / min. Other conditions are the same as in the embodiment. Using the impregnated film 51, an electrolyte film is produced by the same technique (step S500) as in the embodiment.

  FIG. 4 is a diagram showing the production of the impregnated film 52 in Comparative Example 2. As shown in FIG. 4, the impregnated film 52 is produced by disposing the reinforcing film 30 between the two electrolyte single films 20 and performing hot pressing. However, unlike the embodiment, the thickness of the reinforcing film 30 is about 8 μm, and the conveyance speed in the hot press is 0.05 m / min. Other conditions are the same as in the embodiment. Using the impregnated film 52, an electrolyte film is produced by the same technique (step S500) as in the embodiment.

  The surface shape of the electrolyte membrane was compared between the embodiment and Comparative Examples 1 and 2. If there were no wrinkles or voids on the surface, it was judged as OK, and if it was present, it was judged as NG. The embodiment and Comparative Example 1 were OK. Comparative Example 2 was NG because of frequent occurrence of voids.

  Subsequently, an experiment was performed to compare the power generation performance of MEGA produced by the manufacturing method of the embodiment and MEGA produced using the electrolyte membranes of Comparative Examples 1 and 2. The same method (step S600) as in the embodiment was used as the method for manufacturing MEGA in Comparative Examples 1 and 2.

The experimental conditions were as follows: the anode flow rate was 0.5 NL / min, the cathode flow rate was 2.0 NL / min, the anode was humidified at 60 ° C., the cathode was dry, the cell temperature was 83 ° C., the current was 1.2 A / cm ² , The back pressure of the anode and cathode was set to 0.14 MPaG.

  As a result of the experiment, when the generated voltage in the embodiment is 1, the generated voltage in the comparative example 1 is 0.95, and the generated voltage in the comparative example 2 is 1.00. Thus, according to the embodiment, it was confirmed that the abnormality in the surface shape is suppressed and the power generation performance is improved.

  In addition, it is estimated that the reason that the power generation performance was not good in Comparative Example 1 was that the bondability between the electrolyte membrane and the ionomer of the catalyst layer was deteriorated. FIG. 5 schematically shows reinforcing bars exposed on the surface of the electrolyte membrane. When the reinforcing membrane is impregnated from the portion that will be exposed as the outside of the electrolyte membrane as in Comparative Example 1, it is considered that a part of the reinforcing component is exposed on the surface of the electrolyte membrane and deteriorates the bonding property.

  The present invention is not limited to the embodiments, examples, and modifications of the present specification, and can be implemented with various configurations without departing from the spirit of the present invention. For example, the technical features in the embodiments, examples, and modifications corresponding to the technical features in the embodiments described in the summary section of the invention are to solve some or all of the above-described problems, or In order to achieve part or all of the effects described above, replacement or combination can be performed as appropriate. If the technical feature is not described as essential in this specification, it can be deleted as appropriate.

DESCRIPTION OF SYMBOLS 20 ... Electrolyte single membrane 30 ... Reinforcement membrane 40 ... Intermediate impregnation membrane 50 ... Impregnation membrane (embodiment)
51. Impregnated membrane (Comparative Example 1)
52 ... Impregnation membrane (Comparative Example 2)
90 ... Heating roller

Claims (1)

Impregnating a porous reinforcing membrane from a predetermined surface of the electrolyte single membrane;
And a step of bonding the impregnated electrolyte single membranes to each other on the predetermined surfaces.

Images