CN214797467U

CN214797467U - Novel proton exchange membrane fuel electrode structure

Info

Publication number: CN214797467U
Application number: CN202121064143.0U
Authority: CN
Inventors: 田文筱
Original assignee: Shanghai Maole New Material Technology Co ltd
Current assignee: Shanghai Maole New Material Technology Co ltd
Priority date: 2021-05-18
Filing date: 2021-05-18
Publication date: 2021-11-19
Anticipated expiration: 2031-05-18

Abstract

The utility model relates to a novel proton exchange membrane fuel electrode structure, which comprises a proton conductive membrane layer positioned in the middle, catalyst layers coated on two sides of the proton conductive membrane layer in a hot pressing mode, and a diffusion layer compounded on the outer side of the catalyst layers, wherein the diffusion layer comprises a carbon fiber paper layer and a microporous layer coated and burned and solidified on the carbon fiber paper layer, and the microporous layer is made of micro-powder graphite powder or graphene powder; the utility model provides a structure that high hydrophobicity pore structure distributes evenly, the essence is that the conductive carbon black that originally commonly used is replaced with spherical graphite powder or miropowder graphite alkene, changes the pore structure size and the hydrophobic characteristic of micropore layer. The graphite powder is applied to the microporous layer and is used as a main hydrophobic conductive substance of the microporous layer, the pore structure is adjusted by the diameter of the micro powder, and the improvement of the operation stability of the battery under high air metering ratio has special significance.

Description

Novel proton exchange membrane fuel electrode structure

Technical Field

The present invention relates to a fuel cell, and more particularly to a membrane electrode assembly for a fuel cell.

Background

The core component of Proton Exchange Membrane Fuel Cell (PEMFC) is Membrane Electrode (MEA), which is the site of multiphase substance transmission and electrochemical reaction for energy conversion, involving three-phase interface reaction and complex mass and heat transfer process, directly determining the performance, lifetime and cost of fuel cell (PEMFC).

Commercial membrane electrodes are generally 7-layer structures, wherein a CCM-type membrane electrode is a three-layer sandwich structure in which two catalyst layers sandwich a proton-conducting membrane, and the catalyst layer is composed of two diffusion layers with microporous layers on both sides. At present, most of research and materials are focused on the aspects of membrane, catalyst, stability of a diffusion layer structure, high performance and the like. Relatively little research has been done on microporous layers on diffusion layers.

In the current fuel cell application, a microporous layer is generally composed of a microporous layer using conductive carbon powder and Polytetrafluoroethylene (PTFE) as a binder, and the hydrophobicity, the conductivity and the air permeability of the microporous layer are adjusted by adjusting the proportion of the Polytetrafluoroethylene (PTFE), carbon black (VULCAN XC 72), acetylene black and the like in the microporous layer. If the hydrophobicity of the microporous layer is to be increased, this is done by increasing the PTFE content. However, the addition of high content of PTFE increases the hydrophobicity of the electrode, changes the pore structure of the electrode microporous layer and reduces the conductivity.

In some special applications, it is very difficult to adjust the microporous layer structure of the fuel cell to shape the structure of a special function only by the network structure consisting of carbon black (VULCAN XC 72), acetylene black and Polytetrafluoroethylene (PTFE) polymers, because the PTFE has triple composite effects of changing the pore structure, electrical conductivity and hydrophobicity. And the hole structure of this kind of regulation is more complicated, the utility model discloses a new structure that goes on based on the aforesaid problem.

SUMMERY OF THE UTILITY MODEL

The utility model aims to provide a novel proton exchange membrane fuel cell structure has solved fuel cell's micropore layer structure and performance and is difficult to rely on current material to carry out the problem of adjusting.

In order to achieve the above purpose, the utility model adopts the technical scheme that:

the utility model provides a novel proton exchange membrane fuel electrode structure, it is in including the proton conduction rete, the coating hot pressing that are located the centre the catalyst layer, the complex of proton conduction rete both sides be in the diffusion layer in the catalyst layer outside, the diffusion layer include carbon fiber paper layer and coating and firing solidification and be in micropore layer on the carbon fiber paper layer, just micropore layer material be miropowder graphite powder or graphite alkene powder.

Preferably, the size of each micropore of the micropore layer is in the range of 0.05-5 mu m.

Preferably, the particle size of the micro-powder graphite powder or graphene powder is 1000-10000 meshes.

Preferably, the thickness of the diffusion layer is 0.05-0.35 mm.

Preferably, the thickness of the microporous layer is 0.1-0.2 mm.

Because of the application of the technical scheme, compared with the prior art, the utility model has the following advantages:

the utility model discloses a novel proton exchange membrane fuel, including the proton conduction rete that is located the centre, coating hot pressing at the catalyst layer of proton conduction rete both sides, compound in the diffuse layer in the catalyst layer outside, the diffuse layer includes carbon fiber ply and coating and the firing solidification micropore layer on carbon fiber ply, and the micropore layer material is miropowder graphite powder or graphite alkene powder, the utility model provides a structure that high hydrophobicity pore structure distributes evenly, the essence is that spherical graphite powder or miropowder graphite are substituted for original conductive carbon black commonly used, changes the pore structure size and the hydrophobic characteristic of micropore layer. The graphite powder is applied to the microporous layer and is used as a main hydrophobic conductive substance of the microporous layer, the pore structure is adjusted by the diameter of the micro powder, and the improvement of the operation stability of the battery under high air metering ratio has special significance.

Drawings

Some specific embodiments of the present invention will be described in detail hereinafter, by way of illustration and not by way of limitation, with reference to the accompanying drawings. The same reference numbers in the drawings identify the same or similar elements or components. Those skilled in the art will appreciate that the drawings are not necessarily drawn to scale. In the drawings:

FIG. 1 is a schematic structural diagram according to the preferred embodiment of the present invention

Wherein the reference numerals are as follows:

1. a proton conducting membrane layer; 2. a catalyst layer; 3. microporous layer 4, diffusion layer; 5. a carbon fiber paper layer;

Detailed Description

The technical solution of the present invention will be described clearly and completely with reference to the accompanying drawings, and obviously, the described embodiments are some, but not all embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplification of description, but do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. Furthermore, the technical features mentioned in the different embodiments of the invention described below can be combined with each other as long as they do not conflict with each other.

Referring to fig. 1, the proton exchange membrane fuel electrode structure of the present invention includes a proton conductive membrane layer 1 located in the middle, a catalyst layer 2 coated on two sides of the proton conductive membrane layer 1 by hot pressing, and a diffusion layer 3 compounded on the outer side of the catalyst layer 2; the diffusion layer 3 comprises a carbon fiber paper layer 4 and a microporous layer 5 coated and burned on the carbon fiber paper layer 4, and the microporous layer 5 is made of micro-powder graphite powder or graphene powder.

The catalyst layer 2 comprises an anode catalyst layer and a cathode catalyst layer which are respectively coated on two sides of the proton conducting membrane so as to be convenient for supporting enough fields when hydrogen and oxygen in the fuel cell generate electrochemical reaction to generate current, and the catalyst layer 2 is an important constituent material of the electrode.

The commonly used gas diffusion layer materials include carbon fiber paper, carbon fiber woven cloth, non-woven cloth, carbon black paper and the like, in the embodiment, the carbon fiber paper is selected as the bottom layer of the diffusion layer 3, the thickness of the diffusion layer 3 is 0.2mm, and the diffusion layer 3 with the thickness can achieve certain strength on the mechanical property and simultaneously maintain good electrical and thermal properties and gas transmittance.

In the present fuel cell application, micropore layer 5 generally adopts conductive carbon powder and Polytetrafluoroethylene (PTFE) to make the micropore layer of binder and constitutes, adjusts corresponding proportion and adjusts performances such as hydrophobicity, electric conductivity and gas permeability, but increases the content of a certain component and probably reduces a certain performance when increasing a certain performance, the utility model discloses in use the high hydrophobicity conductive material such as micron graphite powder or graphite alkene powder with close size to be used as the structural material of micropore layer to coating and firing solidification are on carbon fiber paper layer 4, and graphite miropowder structural layer has the characteristics that hydrophobicity is strong, the aperture is homogeneous, micropore layer 5 thickness is 0.15mm and every micropore size of micropore layer 5 is in 0.12-0.15 mu m scope, the homoenergetic requirement under the special battery operating condition that satisfies.

The specific steps for making the microporous layer are as follows:

(1) soaking a piece of soft carbon fiber paper with the thickness of 10cm by 10cm in 15% of PTFE emulsion, taking out, slowly drying at the temperature of 80 ℃, drying, and sintering in a muffle furnace at the temperature of 360 ℃.

(2) Taking 2 g of 1000-10000 mesh spherical graphite and a little PTFE emulsion, coating the slurry on carbon fiber paper, curing at high temperature, and carrying out hot pressing treatment. Thus, the super-thick high-hydrophobicity microporous layer with single pore diameter can be prepared.

The following table shows the performance test table of the monocell assembled by using 1000 mesh and 10000 mesh spherical graphite as diffusion layers, wherein the graphite powder microporous layer is contacted with the catalyst. H2, Air, RH =30%, gas inlet temperature 25 degrees, electrode operating temperature 65 degrees, operating pressure 0.6Bar, Air gauge at 35.0.

As can be seen from the data comparison in the following table, the utility model discloses microporous layer structure can adapt to the stable performance demand of fuel cell electrode under high air metering ratio.

The above embodiments are only for illustrating the technical concept and features of the present invention, and the purpose thereof is to enable those skilled in the art to understand the contents of the present invention and to implement the present invention, so as not to limit the protection scope of the present invention, and all equivalent changes or modifications made according to the spirit of the present invention should be covered by the protection scope of the present invention.

Claims

1. The utility model provides a novel proton exchange membrane fuel electrode structure, its includes the proton conduction rete that is located the centre, the coating hot pressing is in the catalyst layer of proton conduction rete both sides, compound the diffusion layer in the catalyst layer outside, its characterized in that: the diffusion layer comprises a carbon fiber paper layer and a microporous layer coated and burned and solidified on the carbon fiber paper layer, and the microporous layer is made of micro-powder graphite powder or graphene powder.

2. The novel proton exchange membrane fuel electrode structure as claimed in claim 1, wherein: the size of each micropore of the micropore layer is within the range of 0.05-5 mu m.

3. The novel proton exchange membrane fuel electrode structure as claimed in claim 1, wherein: the particle size of the micro-powder graphite powder or graphene powder is 1000-10000 meshes.

4. The novel proton exchange membrane fuel electrode structure as claimed in claim 1, wherein: the thickness of the diffusion layer is 0.05-0.35 mm.

5. The novel proton exchange membrane fuel electrode structure as claimed in claim 3, wherein: the thickness of the microporous layer is 0.10-0.20 mm.