JP-7856850-B2 - Method for manufacturing catalyst ink and film electrode assembly

Inventors

• 山本 昌邦
• 櫻井 由貴
• 小茂田 宏章
• 井上 了允

Assignees

• 本田技研工業株式会社

Dates

Publication Date

20260511

Application Date

20240228

Priority Date

20230331

Claims (3)

1. Solvent and, Carbon particles supported with a metal catalyst, The ionomer that adheres the carbon particles together, It contains a dispersion stabilizer, The solvent is a 50-60 weight percent aqueous solution of ethanol. The carbon particle content is 4 to 5 weight percent. A catalyst ink characterized in that the content ratio of the dispersion stabilizer to the ionomer is 6% by weight or more.
2. In the catalyst ink according to claim 1, A catalyst ink characterized in that the content ratio of the dispersion stabilizer to the ionomer is 15% by weight or more.
3. A catalyst ink is prepared containing a solvent, carbon particles on which a metal catalyst is supported, an ionomer that adheres the carbon particles together, and a dispersion stabilizer. The prepared catalyst ink is applied to the gas diffusion layer. A polymer electrolyte film is laminated onto the layer of catalyst ink applied to the gas diffusion layer. The process includes joining the polymer electrolyte membrane, the catalyst ink layer, and the gas diffusion layer by thermocompression bonding. The solvent is a 50-60 weight percent aqueous solution of ethanol. The content ratio of the carbon particles in the catalyst ink is 4 to 5 weight percent. A method for manufacturing a membrane electrode assembly, characterized in that the content ratio of the dispersion stabilizer to the ionomer is 6% by weight or more.

Description

This invention relates to a film electrode assembly, a catalyst ink, and a method for manufacturing a film electrode assembly. Conventionally, a method for manufacturing a membrane electrode assembly is known in which an electrode catalyst layer and a gas diffusion layer are attached to both sides of an electrolyte membrane (see, for example, Patent Document 1). In the manufacturing method described in Patent Document 1, a catalyst ink is coated onto the electrolyte membrane, the gas diffusion layer is bonded while the catalyst ink is still wet, and the catalyst ink is dried while controlling the bonding load of the gas diffusion layer so that the thickness of the ionomer-existing region where the ionomer has entered the gas diffusion layer is 9 to 37% of the total ionomer region. Japanese Patent Publication No. 2013-134877 A schematic perspective view showing the overall configuration of a fuel cell stack including a membrane electrode assembly according to an embodiment of the present invention.Figure 1 is a perspective view showing the schematic configuration of the integrated electrode assembly included in the fuel cell stack.A diagram illustrating a membrane electrode assembly according to an embodiment of the present invention.A diagram illustrating a method for manufacturing a membrane electrode assembly according to an embodiment of the present invention.A diagram illustrating a catalyst ink according to an embodiment of the present invention.Figure 3 is a diagram illustrating the relationship between the amount of ionomer contained in the electrode catalyst layer and the output performance of the fuel cell.A diagram illustrating the ionomer region when the mass concentration of ethanol relative to the solvent is varied as part of the catalyst ink composition.A diagram illustrating the adsorption rate of ionomers to metal catalysts when the mass concentration of the dispersion stabilizer relative to the ionomer is varied as part of the catalyst ink composition.A diagram illustrating the effect of optimizing the composition of the catalyst ink to suppress ionomer penetration.A diagram illustrating the effect of suppressing coating surface defects through the compositional suitability of catalyst inks. Embodiments of the present invention will be described below with reference to Figures 1 to 10. The membrane electrode assembly according to the embodiment of the present invention is a component of a power generation cell that constitutes a fuel cell. The power generation cell is a component of a fuel cell stack, which is a component of a fuel cell. A fuel cell can be mounted on a vehicle, for example, and can generate electricity for driving the vehicle. First, the overall configuration of the fuel cell stack will be described in general terms. Figure 1 is a schematic perspective view showing the overall configuration of a fuel cell stack 100 including a membrane electrode assembly according to an embodiment of the present invention. For convenience, the three mutually orthogonal axial directions shown in the figure will be defined as the longitudinal direction, the left-right direction, and the vertical direction, and the configuration of each part will be described according to this definition. These directions are not necessarily the same as the longitudinal, left-right, and vertical directions of a vehicle. For example, the longitudinal direction in Figure 1 may be the longitudinal direction of a vehicle, the left-right direction, or the vertical direction. As shown in Figure 1, the fuel cell stack 100 has a cell stack 101 formed by stacking a plurality of power generation cells 1 in the front-to-back direction, and end units 102 arranged at both the front and rear ends of the cell stack 101, and the whole has a substantially rectangular parallelepiped shape. The length of the cell stack 101 in the left-to-right direction is longer than the length in the up-to-down direction. For convenience, Figure 1 shows a single power generation cell 1. The power generation cell 1 has an integrated electrode assembly (UEA) 2, which is a membrane electrode structure including an electrolyte membrane and electrodes, and separators 3, 3 arranged on both the front and rear sides of the integrated electrode assembly 2 and sandwiching the integrated electrode assembly 2. The integrated electrode assembly 2 and the separators 3 are arranged alternately in the front-to-back direction. The separator 3 has a pair of thin metal plates, front and rear, with a corrugated cross-section, and these plates are joined together at their outer edges to form a single unit. The separator 3 is made of a conductive material with excellent corrosion resistance, such as titanium, titanium alloy, or stainless steel. Inside the separator 3, a cooling channel through which a cooling medium flows is formed by press molding or the like, and the power generation surface of the power generation cell 1 is cooled by the flow of the cooling medi