CN217522052U

CN217522052U - Fuel cell unit structure, fuel cell and CCM structure

Info

Publication number: CN217522052U
Application number: CN202220981986.5U
Authority: CN
Inventors: 唐军柯; 杨云松; 邹渝泉; 叶思宇; 孙宁; 吴力杰
Original assignee: Hongji Chuangneng Technology Foshan Co ltd
Current assignee: Hongji Chuangneng Technology Foshan Co ltd
Priority date: 2022-04-25
Filing date: 2022-04-25
Publication date: 2022-09-30
Anticipated expiration: 2032-04-25

Abstract

A fuel cell structure and fuel cell and CCM structure, said cell structure comprising at least a 4-layer structure: the CCM comprises a proton conducting membrane, a first catalytic layer and a second catalytic layer, wherein the first catalytic layer and the second catalytic layer are coated on two sides of the proton conducting membrane, and the first sealed frame is arranged between the first gas diffusion layer and the first catalytic layer. The utility model has the advantages that: the amount of the noble metal catalyst can be reduced, the cost of the battery can be reduced, and the utilization rate of the noble metal catalyst can be improved.

Description

Fuel cell unit structure, fuel cell and CCM structure

Technical Field

The utility model relates to a fuel cell technical field especially relates to a fuel cell unit structure and fuel cell and CCM structure.

Background

A fuel cell is a chemical device that directly converts chemical energy possessed by a fuel into electrical energy. The fuel cell uses fuel and oxygen as raw materials, and has no mechanical transmission component, so that the discharged harmful gas is very little, and the service life is long. It follows that fuel cells are the most promising power generation technology from the viewpoint of energy conservation and ecological environment conservation.

The membrane electrode is the heart of the fuel cell stack, where it assumes the core electrochemical reaction function. The membrane electrode (also called three-in-one) consists of a catalyst layer, a proton conducting membrane and a gas diffusion layer. When hydrogen is oxidized to protons at the anode, it is conducted through the proton-conducting membrane to the cathode. The oxygen is reduced at the cathode to form water with the protons transferred. Meanwhile, protons generated by the hydrogen oxidation reaction are transferred to the cathode through an external circuit, and can be used for generating driving electric energy. The cost of the membrane electrode accounts for more than 60 percent of the total cost of the fuel cell stack, wherein the cost of the noble metal catalyst in the CCM accounts for more than 90 percent of the total material cost of the membrane electrode. In CCM configurations, a portion of the proton-conducting membrane that needs to be compressed under the sealant and frame to form a seal is inactive during operation of the fuel cell, is typically between a few millimeters and ten millimeters in length, and if too small, can affect the operation of the sealing process and the sealing of the membrane electrode. In the current preparation process, the whole surface of the proton conducting membrane is usually coated with a noble metal catalyst, which results in large catalyst dosage, so that the noble metal catalyst cannot be fully utilized on the membrane, and waste is caused.

SUMMERY OF THE UTILITY MODEL

The present invention overcomes at least one of the above-mentioned drawbacks of the prior art and provides a low-cost fuel cell unit structure, a fuel cell and a CCM structure.

The purpose of the utility model is realized through the following technical measures:

a fuel cell unit structure, said unit structure comprising at least a 4-layer structure: CCM, first sealed frame, first gas diffusion layer and second gas diffusion layer are located respectively the CCM both sides, the CCM includes proton conduction membrane and first catalysis layer, the second catalysis layer of coating in proton conduction membrane both sides, first sealed frame is located first gas diffusion layer with between the first catalysis layer, its characterized in that, first catalysis layer is the structure distribution who avoids first sealed frame on proton conduction membrane.

The first gas diffusion layer and the second gas diffusion layer provide a channel for reaction gas and generated water for the first catalytic layer and the second catalytic layer, and the contact part of the first sealing frame and the CCM forms effective bonding seal to prevent the leakage of reaction materials. The first catalyst layer and the second catalyst layer are composed of an electrocatalyst and a solid polymer electrolyte and are used for catalyzing the reaction of the cathode and the anode. The first catalyst layer is distributed on the proton conduction membrane in a structure avoiding the first sealing frame, so that the dosage of the catalyst is reduced and the cost is effectively reduced under the condition of not influencing the normal electric conduction of the unit structure. The noble metal catalyst is coated on the electroactive area of the proton conduction membrane, and the carbon is coated on other areas to replace the noble metal catalyst, so that the aims of reducing the using amount of the noble metal catalyst and reducing the cost are fulfilled on the premise of not influencing the sealing performance of the sealing frame.

Furthermore, the fuel cell unit structure further comprises a second sealing frame, the second sealing frame is arranged between the second catalytic layer and the second gas diffusion layer, and the second catalytic layer is distributed on the proton conducting membrane in a structure avoiding the second frame.

Furthermore, the first sealing frame is square, the first sealing frame comprises an upper side port area and an upper side active area, a first filling layer is arranged on the portion, corresponding to the upper side port area, of the upper side of the CCM, the first catalytic layer is formed on the portion, corresponding to the upper side active area, of the upper side of the CCM, and the first filling layer and the first catalytic layer are the same in thickness.

The upper port area is provided with gas and cooling liquid through holes corresponding to the bipolar plates and used for the circulation of materials such as air, hydrogen, cooling media and the like which participate in the reaction. The filling layer and the catalytic layer have the same thickness, so that the sealing frame and the CCM are tightly adhered, and the performance stability of the fuel cell unit is improved. The first filling layer is coated on the CCM corresponding to the first sealing frame, and the filling layer replaces a noble metal catalyst layer, so that the first sealing frame and the CCM are prevented from forming a hollow structure, the cost of the fuel cell is reduced, and the conductivity of the fuel cell unit is ensured.

Furthermore, the second sealing frame is square, the second sealing frame comprises a lower side port area and a lower side active area, a second filling layer is arranged on the portion, corresponding to the lower side port area, of the lower side of the CCM, the second catalytic layer is formed on the portion, corresponding to the lower side active area, of the lower side of the CCM, and the second filling layer and the second catalytic layer are the same in thickness.

Further, the first catalyst layer and the second catalyst layer are noble metal catalysts, the first filling layer or the second filling layer is carbon, the first filling layer surrounds the first catalyst layer and is distributed, and the second filling layer surrounds the second catalyst layer and is distributed.

Further, the fuel cell comprises the fuel cell unit structure, the fuel cell unit structures are continuously and repeatedly arranged into a laminated structure, wherein the second gas diffusion layer of the former fuel cell unit structure and the first gas diffusion layer of the latter fuel cell unit structure are the same layer, and bipolar plates are arranged at two ends of the laminated structure.

The bipolar plate is used for supporting the membrane electrode and separating the cathode and anode reaction gases to prevent the mixing of the cathode and anode reaction gases.

Furthermore, the CCM is formed by coating catalytic layers on two sides of the proton conducting membrane, and the catalytic layers are distributed on the membrane in a structure avoiding a sealed frame.

Furthermore, a filling layer is arranged on the proton conducting membrane corresponding to the sealing frame, and the filling layer is distributed in a surrounding catalytic layer structure.

Further, the thickness of the filling layer is consistent with that of the catalytic layer.

Further, the catalytic layer has a specific area of greater than 85% on the proton-conducting membrane.

To sum up, owing to adopted above technical scheme, the beneficial effects of the utility model are that:

(1) the utility model reduces the dosage of noble metal catalyst and the cost of the membrane electrode of the fuel cell under the condition of not influencing the sealing performance of the sealing frame.

(2) The utility model discloses the coating area of noble metal catalyst on the membrane reduces, reduces the swelling deformation rate of membrane.

(3) The utility model discloses the electroactive region is only coated to the noble metal catalyst, has increased the utilization ratio of noble metal catalyst, has effectively avoided the wasting of resources.

(4) The utility model has strong applicability, is suitable for mass production and is applied to membrane electrodes of various fuel cells.

Drawings

Fig. 1 is a structural diagram of embodiment 1 of the present invention.

Fig. 2 is a structural diagram of embodiment 2 of the present invention.

Fig. 3 is a cross-sectional view of the present invention.

Detailed Description

The drawings of the present invention are for illustration purposes only and are not to be construed as limiting the invention. For a better understanding of the following embodiments, certain features of the drawings may be omitted, enlarged or reduced, and do not represent the size of an actual product; it will be understood by those skilled in the art that certain well-known structures in the drawings and descriptions thereof may be omitted.

Example 1

As shown in fig. 1, the present embodiment provides a fuel cell unit structure, which includes a CCM3, a first sealing frame 2, a first gas diffusion layer 1, and a second gas diffusion layer 4, where the first gas diffusion layer 1 and the second gas diffusion layer 4 are respectively disposed at the upper end and the lower end of the fuel cell unit structure. CCM3 is provided with first catalytic layer 32 and second catalytic layer 34, and first sealed border 2 is provided between first gas diffusion layer 1 and CCM 3.

The first gas diffusion layer 1 and the second gas diffusion layer 4 provide a channel for the reaction gas and the generated water for the first catalytic layer 32 and the second catalytic layer 34, and the contact part of the first sealing frame 2 and the CCM3 forms an effective adhesive seal to prevent the leakage of the reaction materials. The first catalytic layer 32 and the second catalytic layer 34 are composed of an electrocatalyst and a solid polymer electrolyte, and are used for catalyzing the reaction between the anode and the cathode. The first catalytic layer 32 is distributed on the proton conducting membrane in a structure avoiding the first sealing frame 2, so that the dosage of the catalyst can be reduced without influencing the normal electric conduction of the fuel unit structure, and the cost can be effectively reduced.

The two sides of the first sealing frame 2 are provided with upper side port areas 21 which are ports of gas and cooling liquid, and the middle part avoiding frame part is an upper side active area 22. On CCM3, the portion of the membrane corresponding to the upper active region 22 was coated with the noble metal catalyst, and the remaining portion was coated with the first filler layer 31. Preferably, the noble metal catalyst is a platinum catalyst and the first packed layer 31 is carbon. The use of carbon instead of platinum catalyst reduces the amount of precious metal catalyst used, and the use of platinum catalyst is only coated in the upper active zone 22 to improve its utilization and avoid waste.

Example 2

As shown in fig. 2, the present embodiment provides a fuel cell unit structure, which includes a CCM3, a first sealing frame 2, a second sealing frame 5, a first gas diffusion layer 1, and a second gas diffusion layer 4, where the first gas diffusion layer 1 and the second gas diffusion layer 4 are respectively disposed at the upper end and the lower end of the cell unit structure. CCM3 is provided with a first catalytic layer 32 and a second catalytic layer 34. The first sealing rim 2 is provided between the first gas diffusion layer 1 and the first catalytic layer 32. A second sealed frame 5 is disposed between CCM3 and second gas diffusion layer 4.

The first sealing frame 2 is provided with upper side port areas 21 at both sides and upper side active areas 22 at the middle avoiding frame part. On CCM3, the portion of the membrane corresponding to the upper active region 22 was coated with the noble metal catalyst, and the remaining portion was coated with the first filler layer 31. The second sealing frame 5 has lower port regions 51 on both sides and lower active regions 52 on the middle avoiding frame portion. The upper port area 21 and the lower port area 51 are ports for gas and coolant. On the CCM3, the precious metal catalyst is applied to the membrane at the portions corresponding to the upper side active regions 22 and the lower side active regions 52, and the first filling layer 31 is applied to the portions excluding the upper side active regions 22. The second filling layer 33 is applied to the portion corresponding to the lower side active region 52. Preferably, the noble metal catalyst is a Pt/C catalyst and the packed layer is carbon. The use of carbon instead of the Pt/C catalyst reduces the amount of precious metal catalyst used, and the Pt/C catalyst is coated only on the upper and lower

active zones

22 and 52 to improve the utilization rate thereof, thereby avoiding waste.

Claims

1. A fuel cell unit structure, said unit structure comprising at least a 4-layer structure: the CCM comprises a proton conducting membrane, a first catalytic layer and a second catalytic layer, wherein the first catalytic layer and the second catalytic layer are coated on two sides of the proton conducting membrane, and the first sealed frame is arranged between the first gas diffusion layer and the first catalytic layer.

2. The fuel cell unit structure of claim 1, further comprising a second sealing frame disposed between the second catalytic layer and the second gas diffusion layer, wherein the second catalytic layer is disposed on the proton conducting membrane in a structure avoiding the second frame.

3. A fuel cell unit structure according to claim 2, characterized in that said first sealing frame is square in shape, said first sealing frame comprising an upper side port area and an upper side active area, said upper side of the CCM being provided with a first filling layer in correspondence of the upper side port area, said first catalytic layer being formed in correspondence of the upper side active area portion, said first filling layer being of the same thickness as the first catalytic layer.

4. A fuel cell unit structure according to claim 3, wherein said second sealing frame is square in shape, said second sealing frame comprising a lower port area and a lower active area, a portion of the underside of the CCM corresponding to the lower port area being provided with a second filler layer, said second catalytic layer being formed on the portion of the underside of the CCM corresponding to the lower active area, said second filler layer being the same thickness as the second catalytic layer.

5. The fuel cell unit structure of claim 4, wherein the first and second catalytic layers are noble metal catalysts, the first or second filler layer is carbon, the first filler layer is distributed around the first catalytic layer, and the second filler layer is distributed around the second catalytic layer.

6. A fuel cell comprising the fuel cell unit structure according to any one of claims 1 to 5, which is repeatedly arranged in series in a stacked structure in which the second gas diffusion layer of the preceding fuel cell unit structure and the first gas diffusion layer of the succeeding fuel cell unit structure are the same layer, and bipolar plates are provided at both ends of the stacked structure.

7. A CCM structure with reduced cost is characterized in that the CCM structure is formed by coating catalytic layers on two sides of a proton conduction membrane, and the catalytic layers are distributed on the membrane in a structure avoiding a sealed frame.

8. The CCM structure of claim 7, wherein a portion of the proton conducting membrane corresponding to the sealing frame is provided with a filling layer, and the filling layer is distributed around the catalytic layer structure.

9. The reduced cost CCM structure of claim 8 wherein the fill layer thickness is the same as the catalytic layer thickness.

10. The reduced cost CCM structure of claim 7 wherein the catalytic layer has a specific area on the proton conducting membrane of greater than 85%.