CN210837968U

CN210837968U - Membrane electrode structure, membrane electrode, fuel cell monocell and fuel cell stack

Info

Publication number: CN210837968U
Application number: CN201921462879.6U
Authority: CN
Inventors: 张永; 陈晓; 张威; 肖彪
Original assignee: Gree Electric Appliances Inc of Zhuhai
Current assignee: Gree Electric Appliances Inc of Zhuhai
Priority date: 2019-09-04
Filing date: 2019-09-04
Publication date: 2020-06-23
Anticipated expiration: 2029-09-04

Abstract

The utility model provides a membrane electrode structure is equipped with the diffusion mass transfer structure that porous conducting medium constitutes, and diffusion mass transfer structure is formed with gas transmission layer and gas diffusion layer integratively. The flow field plate in the fuel cell with the traditional structure can be replaced, the structure of the fuel cell can be simplified, and the task amount of flow field design is obviously reduced; in addition, the diffusion mass transfer structure formed by the porous conductive medium obviously improves the gas diffusion mass transfer capability and the mass transfer uniformity, and achieves the aims of improving the performance of the fuel cell and reducing the design cost on the whole. And simultaneously solves the corrosion protection problem.

Description

Membrane electrode structure, membrane electrode, fuel cell monocell and fuel cell stack

Technical Field

The utility model relates to a fuel cell technical field especially relates to a membrane electrode structure, membrane electrode, fuel cell monocell and fuel cell pile.

Background

Currently, a membrane electrode of a proton exchange membrane fuel cell (hereinafter referred to as a fuel cell) generally refers to a composite structure including a proton exchange membrane, a catalyst layer and a gas diffusion layer, and the thickness of the membrane electrode is generally 0.2-0.5 mm. The supply of the reaction gas on the membrane electrode depends on an external flow field, and the traditional commonly adopted gas supply flow field is in a form of alternately distributing grooves and ridges, and the form often has the conditions of poor gas mass transfer performance and uneven flow distribution. The prior art proposes a method of adopting a porous medium such as foam metal as a gas diffusion layer, so that the diffusion mass transfer capacity and uniformity of gas are improved, but the foam metal material has the problem that corrosive protection cannot be applied.

SUMMERY OF THE UTILITY MODEL

In view of this, the utility model provides a membrane electrode structure is equipped with the diffusion mass transfer structure that porous conducting medium constitutes, and the diffusion mass transfer structure is formed with gas transmission layer and gas diffusion layer integratively. The capacity of gas diffusion mass transfer is obviously improved, the uniformity of mass transfer is improved, the structure of the fuel cell is simplified, and the task amount of flow field design is obviously reduced; and simultaneously, the problem of corrosion is avoided. Overall, the goals of improving fuel cell performance and reducing design cost are achieved. Specifically, the method comprises the following steps:

the utility model provides a membrane electrode structure is equipped with the diffusion mass transfer structure that porous conducting medium constitutes, diffusion mass transfer structure is formed with gas transmission layer and gas diffusion layer integratively. Compared with the prior art, the integrated structure has the advantages that the contact resistance of the gas transmission layer and the gas diffusion layer is almost zero, and the performance of the fuel cell is greatly improved.

Further optionally, the gas transport layer employs a porous conductive medium; the gas diffusion layer is integrally formed on the surface of the porous conductive medium in the process of forming the gas transmission layer by the porous conductive medium, so that the capacity of gas diffusion mass transfer is improved, the uniformity of mass transfer is improved, and the structure of the fuel cell is simplified.

Further alternatively, the gas diffusion layer is integrally formed on the surface of the porous conductive medium in a coating manner. Specifically, when the gas transmission layer is prepared, the porous conductive material for preparing the gas diffusion layer is coated on the surface of the porous material for preparing the gas transmission layer, and then pressing processing is carried out.

Further optionally, the porous conductive medium is porous conductive metal, so that the process of gas transmission and diffusion can be fully guaranteed, and meanwhile, the gas transmission layer is guaranteed to have good conductivity.

Further optionally, the porous conductive medium is coated with a carbon fiber structure material on the surface to form a gas diffusion layer. The carbon fiber structure material comprises a carbon fiber composite material, carbon fiber paper, carbon fiber woven cloth, non-woven cloth and carbon black paper, and the design ensures that the gas diffusion layer can support the catalyst layer, collect current, conduct gas and discharge water as a reaction product.

Further optionally, the pores of the gas transmission layer are wrapped with an anticorrosive layer, so that electrochemical corrosion in the working process of the fuel cell can be effectively avoided or weakened, and the service life of the fuel cell is prolonged.

Further optionally, the anticorrosive layer is a PTFE layer, which not only ensures the anticorrosive effect, but also has good hydrophobic property and gas transmission property, and improves the performance of the fuel cell.

Further optionally, the gas diffusion layer has a thickness of 0.7mm to 1.3mm and the gas transport layer has a thickness of 0.1mm to 2 mm.

Further optionally, the direction of the porous conductive medium layer away from the proton exchange membrane is gradually increased. The part close to the proton exchange membrane has smaller porosity, so that the gas transmission is more uniform, the saturated vapor pressure of water is favorably improved, and the part far away from the membrane has larger porosity, so that the gas transmission resistance is conveniently reduced.

The utility model also provides a membrane electrode is equipped with gas transmission layer, gas diffusion layer and proton exchange membrane, gas transmission layer, gas diffusion layer form above-mentioned arbitrary membrane electrode structure. Wherein, the two sides of the proton exchange membrane are respectively provided with the gas transmission layer and the gas diffusion layer.

Further alternatively, the lower half of the gas diffusion layer for contact with the proton exchange membrane is coated with a microporous layer for good contact with the proton exchange membrane and to increase the contact area of the reaction gas with the membrane electrode.

Further optionally, a catalytic layer is formed on the surface of the proton exchange membrane, and the catalytic layer and the microporous layer form good contact to reduce contact resistance.

The utility model provides a fuel cell monocell has the membrane electrode structure of above-mentioned arbitrary any or the membrane electrode of any.

The utility model provides a fuel cell pile, which is formed by stacking the fuel cell monocells.

The utility model provides a membrane electrode structure is equipped with the diffusion mass transfer structure that porous conducting medium constitutes, and diffusion mass transfer structure is formed with gas transmission layer and gas diffusion layer integratively. The following beneficial effects are realized:

(1) the structure of the fuel cell can be simplified, and the task amount of flow field design is obviously reduced;

(2) the capacity of gas diffusion mass transfer is obviously improved, and the uniformity of mass transfer is improved;

(3) improving fuel cell performance and reducing design cost;

(4) the problem of corrosion protection is solved.

Drawings

The above and other objects, features and advantages of the present disclosure will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings. The drawings described below are merely some embodiments of the present disclosure, and other drawings may be derived from those drawings by those of ordinary skill in the art without inventive effort.

FIG. 1 is a schematic diagram of a fuel cell stack according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of a structure of a single fuel cell in an embodiment of the present invention;

FIG. 3 is a schematic diagram illustrating an explosion of a single cell structure of a fuel cell according to an embodiment of the present invention;

FIG. 4 is a schematic view of a membrane electrode structure according to an embodiment of the present invention;

FIG. 5 is a schematic view of a membrane electrode assembly according to an embodiment of the present invention;

1-a fuel cell unit cell; 2-anode current collector; 21-anode gas inlet; 3-a cathode collector plate; 31-anode gas inlet; 4-a membrane electrode; 41-sealing ring; 42-a proton exchange membrane; 43-a gas diffusion layer; 431-a microporous layer; 44-a gas transport layer;

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that 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.

The terminology used in the embodiments of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used in the embodiments of the present invention and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise, and "a plurality" typically includes at least two, but does not exclude the presence of at least one.

It should be understood that the term "and/or" as used herein is merely one type of association that describes an associated object, meaning that three relationships may exist, e.g., a and/or B may mean: a exists alone, A and B exist simultaneously, and B exists alone. In addition, the character "/" herein generally indicates that the former and latter related objects are in an "or" relationship.

It is also noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a good or system that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such good or system. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other like elements in a commodity or system that includes the element.

The utility model provides a membrane electrode structure is equipped with the diffusion mass transfer structure that porous conducting medium constitutes, and diffusion mass transfer structure is formed with gas transmission layer and gas diffusion layer integratively. Firstly, the structure of the fuel cell can be simplified, and the task amount of flow field design is obviously reduced; in addition, the diffusion mass transfer structure formed by the porous conductive medium obviously improves the gas diffusion mass transfer capability and the mass transfer uniformity, and achieves the aims of improving the performance of the fuel cell and reducing the design cost on the whole.

Example 1:

as shown in fig. 4 to 5, the present embodiment provides a membrane electrode structure provided with a diffusion mass transfer structure of a porous conductive medium, which is integrally formed with a gas transport layer 44 and a gas diffusion layer 43 using a porous conductive medium. Further preferably, the porous conductive medium is a porous conductive metal, which can fully ensure the gas transmission diffusion process and ensure that the gas transmission layer 44 has good conductivity. Preferably, the gas diffusion layer 43 is integrally formed on the surface of the porous conductive medium by coating during the process of forming the gas transmission layer 44 from the porous conductive medium. It is further preferable that the coated material is a carbon fiber structural material to form the gas diffusion layer 43, wherein the carbon fiber structural material includes a carbon fiber composite material, a carbon fiber paper, a carbon fiber woven fabric, a non-woven fabric and a carbon black paper, and the design ensures that the gas diffusion layer 43 can support a catalyst layer, collect current, conduct gas and discharge water as a reaction product.

Specifically, when the gas transmission layer 44 is prepared, the carbon fiber structural material for preparing the gas diffusion layer 43 is coated on the surface of the porous metal material for preparing the gas transmission layer 44, and then pressing processing is performed, so that the gas diffusion mass transfer capacity is improved, the mass transfer uniformity is improved, and the fuel cell structure is simplified.

Preferably, the pores of the gas transport layer 44 are coated with a PTFE corrosion protection layer, i.e., the membrane electrode structure is treated with a PTFE solution (at least the porous metal media portion and the carbon fiber-bonded portion need to be immersed in the PTFE solution), and gas is introduced into the porous media structure during the treatment process to prevent the porosity from being excessively blocked, so that the PTFE coating is more uniform and the coating is thinner. The technological parameters of the actual preparation process need to be determined according to the parameters of the membrane electrode to be prepared. The design can effectively avoid or weaken the electrochemical corrosion of the fuel cell in the working process, prolong the service life of the fuel cell, and has good hydrophobic property and gas transmission property, thereby improving the performance of the fuel cell.

Preferably, the gas diffusion layer 43 has a thickness of 0.7mm to 1.3mm and the gas transport layer 44 has a thickness of 0.1mm to 2 mm. More preferably, the gas transmission layer 44 has a thickness of about 1 mm. Preferably, the layer of porous conductive media increases in size away from the proton exchange membrane 42. The smaller porosity of the portion of the membrane near the proton exchange membrane 42 provides more uniform gas transport and facilitates increasing the saturated vapor pressure of water, and the larger porosity of the portion of the membrane away from the membrane facilitates reducing gas transport resistance.

As shown in fig. 1 to 3, the present embodiment also provides a hydrogen fuel cell stack using the membrane electrode structure, a hydrogen fuel cell unit 1 stacked to constitute the hydrogen fuel cell stack includes an anode current collecting plate 2, a cathode current collecting plate 3, and a membrane electrode 4, and the membrane electrode 4 has the above-mentioned membrane electrode structure, and is provided with a gas transport layer 44, a gas diffusion layer 43, and a proton exchange membrane 42. Wherein, the two sides of the proton exchange membrane 42 are respectively provided with a gas transmission layer 44 and a gas diffusion layer 43. Preferably, the gas diffusion layer 43 is provided with a microporous layer 431 in good contact with the proton exchange membrane 42, and preferably, a catalytic layer is formed on the surface of the proton exchange membrane 42 and is in good contact with the microporous layer 431. Preferably, the side of the membrane electrode 4 is sealed by a sealing ring 41 to ensure that the reaction process gas and the generated liquid do not overflow. Compared with the prior art, the integrated structure has the advantages that the contact resistance between the gas transmission layer 44 and the gas diffusion layer 43 is almost zero, the contact area between the reaction gas and the membrane electrode is increased, and the performance of the fuel cell is greatly improved.

The utility model provides a have the utility model discloses membrane electrode mechanism's hydrogen fuel cell pile is at the in-process of work, hydrogen and air flow in respectively from positive pole air inlet 21 and negative pole air inlet 31 and react in reaching the proton exchange membrane 42 that has the catalysis layer through the hole of gas transmission layer 44 and gas diffusion layer 43, because be closer to proton exchange membrane 42 hole and diminish more and less, this transmission resistance is less when getting into the membrane electrode that has just guaranteed hydrogen and air, it is gaseous more even to react, hydrogen fuel cell's reaction efficiency has been increased, and the cost is saved.

To sum up, the utility model discloses the novelty provides a membrane electrode structure, is equipped with the diffusion mass transfer structure that porous conducting medium constitutes, and the diffusion mass transfer structure is formed with gas transmission layer and gas diffusion layer integratively. The flow field plate in the fuel cell with the traditional structure can be replaced, the structure of the fuel cell can be simplified, and the task amount of flow field design is obviously reduced; in addition, the diffusion mass transfer structure formed by the porous conductive medium obviously improves the gas diffusion mass transfer capability and the mass transfer uniformity, and achieves the aims of improving the performance of the fuel cell and reducing the design cost on the whole. Meanwhile, the corrosion protection problem of the porous metal medium is solved.

Exemplary embodiments of the present disclosure are specifically illustrated and described above. It is to be understood that the present disclosure is not limited to the precise arrangements, instrumentalities, or instrumentalities described herein; on the contrary, the disclosure is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

Claims

1. A membrane electrode structure characterized by: a diffusion mass transfer structure of porous conductive media is provided, which is integrally formed with a gas transport layer (44) and a gas diffusion layer (43).

2. The membrane electrode structure of claim 1 wherein: wherein the content of the first and second substances,

the gas transmission layer (44) adopts a porous conductive medium;

the gas diffusion layer (43) is integrally formed on the surface of the porous conductive medium during the process of forming the gas transmission layer (44) from the porous conductive medium.

3. The membrane electrode structure of claim 2 wherein: the gas diffusion layer (43) is integrally formed on the surface of the porous conductive medium in a coating manner.

4. The membrane electrode structure of claim 1 wherein: the porous conductive medium is porous conductive metal.

5. The membrane electrode structure of claim 1 wherein: the surface of the porous conductive medium is coated with carbon fiber structure material to form a gas diffusion layer (43).

6. The membrane electrode structure of claim 1 wherein: the thickness of the gas diffusion layer (43) is 0.7mm-1.3mm, and the thickness of the gas transmission layer (44) is 0.1mm-2 mm.

7. The membrane electrode structure of claim 1 wherein: the pores of the gas transmission layer (44) are wrapped with an anticorrosive layer.

8. The membrane electrode structure of claim 7 wherein: the anticorrosive coating is a PTFE layer.

9. A membrane electrode structure according to any one of claims 1 to 8, wherein: the direction of the porous conducting medium layer far away from the proton exchange membrane (42) is gradually increased.

10. A membrane electrode, characterized by: a gas transmission layer (44) and a gas diffusion layer (43) are respectively formed on two sides of a proton exchange membrane (42), and the gas transmission layer (44) and the gas diffusion layer (43) form a membrane electrode structure according to any one of claims 1 to 9.

11. The membrane electrode of claim 10, wherein: the lower half of the gas diffusion layer (43) for contact with the proton exchange membrane (42) is coated with a microporous layer.

12. The membrane electrode of claim 11, wherein: the surface of the proton exchange membrane (42) is provided with a catalytic layer, and the microporous layer (431) is arranged on the catalytic layer.

13. A fuel cell, characterized in that: has a membrane electrode structure according to any one of claims 1 to 9 or a membrane electrode (4) according to any one of claims 10 to 12.

14. A fuel cell stack constituted by stacking fuel cells (1) according to claim 13.