KR-20260064577-A - PROTON CONDUCTOR GAS SENSOR

Abstract

The proton conductor gas sensor (2) is equipped with a membrane electrode assembly (MEA) (20), a diffusion control panel (6), a filter, and a housing. The diffusion control panel (6) is equipped with a disc-shaped projection (22) that protrudes opposite to the MEA, centered on the diffusion control section (24), and a gap (26) exists between the projection (22) and the MEA (20). Reduces the output deviation of the proton conductor gas sensor.

Inventors

• 스기타 노리오

Assignees

• 피가로 기켄 가부시키가이샤

Dates

Publication Date

20260507

Application Date

20251027

Priority Date

20241031

Claims (5)

1. A membrane electrode assembly (MEA) comprising a proton conductive membrane, catalytic electrodes on both sides thereof, and a pair of gas diffusion layers provided on the side opposite to the proton conductive membrane when viewed from the catalytic electrode, and A diffusion control panel equipped with a diffusion control unit that contacts one side of the MEA to press the MEA and also supplies an atmosphere to the MEA, and A filter that supplies atmosphere to the diffusion control panel, and A proton conductor gas sensor comprising a housing that accommodates an MEA, a diffusion control panel, and a filter, A diffusion control panel is provided with a projection that protrudes to the opposite side of the MEA, centered on the diffusion control section, and A gap exists between the above protrusion and the MEA. A proton conductor gas sensor characterized by
2. In paragraph 1, A sealing body that accommodates the above filter and further has an atmosphere inlet on the side opposite to the diffusion control panel when viewed from the filter, and an atmosphere supply port on the diffusion control panel side. The seal is fixed to the housing and is also pressed by a gasket to contact the diffusion control panel, and The above-mentioned projection of the diffusion control is received within the atmosphere supply port of the seal, and A proton conductor gas sensor characterized in that the atmosphere supply port of the seal is larger in diameter than the protrusion of the diffusion control panel.
3. In paragraph 2, A proton conductor gas sensor characterized in that the atmosphere supply port of the sealing body has a thickness greater than the height of the protrusion, and there is a gap between the protrusion and the filter.
4. In paragraph 3, A proton conductor gas sensor characterized in that the sealing body has a ring-shaped projection protruding in the opposite direction from the diffusion control panel around the atmosphere supply port, and the atmosphere supply port of the sealing body has an increased thickness due to the ring-shaped projection.
5. In paragraph 2, The above filter is characterized by having a recess at a location facing the atmosphere supply port, a proton conductor gas sensor.

Description

Proton Conductor Gas Sensor The present invention relates to a proton conductor gas sensor, and in particular to a diffusion control unit from a seal to a membrane electrode assembly (MEA). The applicant proposed a proton conductor gas sensor comprising an MEA, a seal, and a diffusion control panel (Patent Document 1: USP7393505B). The seal is a container comprising two metal plates that accommodate a filter, such as activated carbon, in an internal space. Ambient atmosphere is introduced, for example, from a side or top surface of the seal, processed by the filter, and supplied through an opening on the MEA side. Additionally, the seal serves as an output terminal on the detection electrode side of the gas sensor. A diffusion control panel is located between the opening on the MEA side of the seal and the MEA, and atmosphere is supplied to the MEA from a diffusion control port of the diffusion control panel. The MEA includes a central proton conductor membrane, catalyst electrodes on both sides thereof, and a gas diffusion layer on the outer side. The catalyst electrodes include carbon supporting an electrode catalyst such as Pt and a proton conductor such as Nafion (Nafion is a registered trademark of DuPont). The gas diffusion layer includes carbon such as carbon black or activated carbon, or a carbon sheet, and is porous enough to diffuse gas and also possesses conductivity. In addition, Teflon and Nafion (Teflon is a registered trademark of DuPont) are added as binders to control the degree of hydrophobicity and hydrophilicity of the gas diffusion layer. In this gas sensor, the amount of atmosphere supplied to the MEA is controlled by controlling the size of the diffusion control port, thereby obtaining an output proportional to the gas concentration in the atmosphere. Additionally, a hole of precise size is drilled in the thin diffusion control panel. FIG. 1 is a cross-sectional view of a proton conductor gas sensor of an embodiment. FIG. 2 is an enlarged cross-sectional view of the main parts of the diffusion control panel and MEA in the embodiment. FIG. 3 is an enlarged cross-sectional view of the main parts of the diffusion control panel and MEA in a conventional example. Figure 4 is a characteristic diagram showing the distribution of CO sensitivity in the examples, conventional examples, and comparative examples. Figure 5 is a micrograph of a cross-section of the main part of the gas sensor of the embodiment, showing the gap between the MEA and the diffusion control panel. Figure 6 is a micrograph of a cross-section of the main part of a conventional gas sensor, showing that the gas diffusion layer material of the MEA is contained in the diffusion control section. FIG. 7 is a cross-sectional view of a proton conductor gas sensor of a modified example. FIG. 8 is a cross-sectional view of a proton conductor gas sensor of a second modified example. FIG. 9 is a cross-sectional view of a proton conductor gas sensor of the third modified example. FIG. 10 is an enlarged cross-sectional view of the main part of a proton conductor gas sensor of a second embodiment. FIG. 11 is an enlarged plan view of the main parts of the sealant and diffusion control panel in the second embodiment. FIG. 12 is an enlarged cross-sectional view of the main part of the proton conductor gas sensor of the third embodiment. Optimal embodiments for carrying out the present invention are described below. Examples FIG. 1 shows a proton conductor gas sensor (2) of an embodiment, and FIG. 2 shows its main parts. FIG. 4 is a metal can, and a disc-shaped metal bottom plate (5) is placed on the top, and the can (4) has a side wall (18) on its outer periphery. The bottom plate (5) may be omitted. FIG. 20 is an MEA, the bottom surface is in contact with the bottom plate (5), the top surface is in contact with a metal diffusion control panel (6), and the bottom surface of a metal seal (8) is in contact with the top surface of the diffusion control panel (6). The seal (8) is a disc-shaped container containing a pair of metal plates, and contains a filter (12) such as activated carbon, silica gel, zeolite, or alumina inside, has an atmosphere inlet (10) on the top or side, and an atmosphere supply port (14) on the bottom. The seal (8) is pressed toward the diffusion control panel (6) by a ring-shaped gasket (16), and this pressure maintains the electrical connection between the seal (8), the diffusion control panel (6), the MEA (20), the bottom plate (5), and the can (4). The diffusion control panel (6) is provided with a disc-shaped protrusion (22), and the protrusion (22) is provided with, for example, one diffusion control port (24) at its center. The protrusion (22) has a smaller diameter than the atmosphere supply port (14) and is housed inside it. In addition, there is a gap (26) between the protrusion (22) and the MEA (20). In addition, multiple diffusion control ports (24) may be provided on the protrusion (22). FIG. 2 shows a diffu