CN114420947B

CN114420947B - Vulcanized silicone rubber injection molding material, integrated sealing membrane electrode, preparation method thereof and fuel cell

Info

Publication number: CN114420947B
Application number: CN202210077999.4A
Authority: CN
Inventors: 于力娜; 张中天; 唐柳; 王绍杉; 朱雅男
Original assignee: FAW Jiefang Automotive Co Ltd
Current assignee: FAW Jiefang Automotive Co Ltd
Priority date: 2022-01-24
Filing date: 2022-01-24
Publication date: 2023-12-12
Anticipated expiration: 2042-01-24
Also published as: CN114420947A

Abstract

The invention provides a vulcanized silicone rubber injection molding material, an integrated sealing membrane electrode, a preparation method thereof and a fuel cell, wherein the preparation method of the vulcanized silicone rubber injection molding material comprises the following steps: mixing silica gel, silicone oil, an auxiliary agent, a cross-linking agent and a vulcanizing agent to obtain the vulcanized silicone rubber injection molding material; the auxiliary agent comprises nano zinc oxide and nano titanium dioxide. According to the invention, the tolerance of the vulcanized silicone rubber injection molding material under high humidity, high temperature and acidic environment is obviously improved by adding the auxiliary agent, and the injection molding material serving as the membrane electrode can meet the requirement of the commercial vehicle fuel cell on the tightness, so that the service life of the commercial vehicle fuel cell is further prolonged.

Description

Vulcanized silicone rubber injection molding material, integrated sealing membrane electrode, preparation method thereof and fuel cell

Technical Field

The invention belongs to the technical field of fuel cells for new energy vehicles, and particularly relates to a vulcanized silicone rubber injection molding material, an integrated sealing membrane electrode, a preparation method thereof and a fuel cell.

Background

The hydrogen fuel cell utilizes the reaction of hydrogen and oxygen to directly convert chemical energy into electric energy, and the proton exchange membrane fuel cell has the characteristics of low working temperature, quick start, high power density, mature application and the like, and is widely applied to automobiles. However, the current commercial vehicle hydrogen fuel cell has poor durability, the average service life is 15000 hours, and the service life requirement comparable with that of an internal combustion engine is not met, so that the service life improvement is one of the most important problems in popularization and application of the commercial vehicle fuel cell.

The membrane electrode is an important component of the hydrogen fuel cell of the commercial vehicle, is an electrochemical reaction generating place and is compared with a chip of the fuel cell, and the cost occupies more than 60% of the fuel cell, so the cost and the service life of the membrane electrode directly determine the cost and the service life of the fuel cell. In order to ensure that hydrogen fuel and oxidant air in the proton exchange membrane fuel cell can be respectively arranged on the two side surfaces of the membrane electrode without occurrence of round, besides the sealing performance of the membrane electrode, the sealing technology around the membrane electrode is also important, and the performance and durability of the cell are directly affected. At present, the membrane electrode seal mainly comprises two plastic frames and injection molding integrated seal.

CN107534166a discloses a sealing member for a solid polymer electrolyte fuel cell, by providing a frame surrounding the periphery of a membrane electrode assembly, bonding (or hot-pressing) the frame and a proton exchange membrane together, and injecting a flowable sealing material and realizing sealing by using through holes on the frame, the integration effect is good, and the production efficiency is high.

CN112103542a discloses a preparation device and a preparation method of an integrated membrane electrode, by placing an electrode product in a lower die and then injection molding from an upper die into a positioning concave cavity, the processing of the electrode product is completed, the automatic production of the membrane electrode is realized, and the labor cost is low; and the electrode product is sealed by using an injection molding mode, the sealing effect of the finished product is good, the sealing is not easy to lose efficacy, and the structure of the membrane electrode is stable.

CN112310431a discloses an elastomer cell frame for a fuel cell, a method of manufacturing the same, and a unit cell, using an elastomer cell frame for a fuel cell, comprising: a membrane electrode assembly including an electrolyte membrane, a pair of catalytic layers disposed on both sides of the electrolyte membrane, and a pair of gas diffusion layers disposed on both sides of the membrane electrode assembly; an elastomeric cell frame surrounding the outer edges of the membrane electrode assembly. The overlapped portion of the membrane electrode assembly and the elastic body frame is thermally fusion bonded by applying hot pressing to the overlapped portion, thereby integrating the membrane electrode assembly and the elastic body frame with each other to constitute an integrated membrane electrode. The method can reduce the material cost, save the adhesive coating process and the molding process of the sealing member, and improve the production efficiency; the space between the cells can be reduced, the weight is reduced, and the volume/mass power of the fuel cell stack is improved.

The above-mentioned documents are all based on improving the integrated membrane electrode at the mould design level, solve the gas tightness problem of membrane electrode, the sealed effect of finished product is good, realizes continuous quick production, has further improved production efficiency. But the problems of attack of educts of injection molding materials on a proton membrane and a catalyst in an aging process, hydrophobic of an integrated membrane electrode and the like are not considered, and the influence on the durability and the service life of the fuel cell of the commercial vehicle is avoided.

Disclosure of Invention

Aiming at the defects existing in the prior art, the invention aims to provide the vulcanized silicone rubber injection molding material, the integrated sealing membrane electrode, the preparation method thereof and the fuel cell, wherein the tolerance of the vulcanized silicone rubber injection molding material under high humidity and high temperature and acidic environment is obviously improved by adding the auxiliary agent, the vulcanized silicone rubber injection molding material is suitable for being used as the injection molding material of the membrane electrode in the fuel cell of the commercial vehicle, the air tightness and the durability of the membrane electrode can be obviously improved, the requirement of the fuel cell of the commercial vehicle on the sealing performance is met, and the service life of the fuel cell of the commercial vehicle is further prolonged.

To achieve the purpose, the invention adopts the following technical scheme:

in a first aspect, the present invention provides a method for preparing a vulcanized silicone rubber injection molding material, the method comprising:

mixing silica gel, silicone oil, an auxiliary agent, a cross-linking agent and a vulcanizing agent, and reacting to obtain the vulcanized silicone rubber injection molding material;

the auxiliary agent comprises nano zinc oxide and nano titanium dioxide.

The vulcanized silicone rubber prepared by the invention is room temperature vulcanized silicone Rubber (RTV), nano zinc oxide is adopted as an auxiliary agent, the nano zinc oxide is dispersed and filled into the silicone rubber, nano zinc oxide particles are adsorbed on the surface of the silicone rubber, and the terminal silicon hydroxyl (O-Si-R) of the silicone rubber is wrapped, meanwhile, the movement of a polymer molecular chain is limited, so that the silicone rubber is difficult to generate a unbuckling degradation reaction and a hydrolysis reaction caused by the terminal hydroxyl, the breakage of the terminal silicon hydroxyl of the silicone rubber in a damp and hot environment is inhibited, and the thermal stability of the room temperature vulcanized silicone rubber is improved.

Meanwhile, nano titanium dioxide is added as an acid-resistant auxiliary agent, and the acid-resistant auxiliary agent has high adhesion and good chemical stability in an acid-base environment, is dispersed in the room temperature vulcanized silicone rubber, and can effectively improve the acid resistance of the silicone rubber. By adding the auxiliary agent, the tolerance of the vulcanized silicone rubber under the high humidity and high temperature and the acidic environment is improved. Therefore, the vulcanized silicone rubber material provided by the invention is suitable for being used as a membrane electrode injection molding material, and the stability and durability of the injection molding material under the working environment (high temperature, high humidity and acidity) of a fuel cell are improved.

According to the invention, the additive is added, so that the tolerance of the vulcanized silicone rubber injection molding material under high humidity, high temperature and acidic environment is obviously improved, and the injection molding material serving as the membrane electrode can meet the requirement of the fuel cell for the vehicle on the tightness, and further the service life of the fuel cell for the commercial vehicle is prolonged. In addition, the auxiliary agent can also comprise nano aluminum oxide and/or nano calcium oxide.

As a preferable technical scheme of the invention, the preparation method specifically comprises the following steps:

(1) Mixing the silica gel and the silicone oil, adding an auxiliary agent, and then sequentially carrying out dispersion treatment and dehydration treatment to obtain a base material;

(2) And after the base material is mixed with the cross-linking agent, adding the vulcanizing agent to react to obtain the vulcanized silicone rubber injection molding material.

Preferably, the silica gel comprises any one of polymethylsiloxane, alpha, omega-dihydroxy polydimethylsiloxane or polydimethylsiloxane, more preferably hydroxy-terminated polydimethylsiloxane.

The silica gel of the present invention may be a polymethylsiloxane, an alpha, omega-dihydroxydimethicone, a dimethicone containing alkoxy groups or other reactive groups, most preferably a hydroxy terminated dimethicone.

Preferably, the silicone oil comprises any one or a combination of at least two of methyl silicone oil, ethyl silicone oil, phenyl silicone oil, methyl hydrogen silicone oil, methyl phenyl silicone oil, methyl chlorophenyl silicone oil, methyl ethoxy silicone oil, methyl trifluoropropyl silicone oil and methyl vinyl silicone oil.

Preferably, the silica gel and silicone oil are mixed under stirring.

Preferably, the mixing time of the silica gel and the silicone oil is 30 to 60min, for example, 30min, 32min, 35min, 38min, 40min, 42min, 45min, 48min, 50min, 52min, 55min, 58min or 60min, but not limited to the recited values, and other non-recited values within the range of values are equally applicable.

The temperature at which the silica gel and the silicone oil are mixed is preferably 100 to 130 ℃, and may be, for example, 100 ℃, 102 ℃, 105 ℃, 108 ℃, 110 ℃, 112 ℃, 115 ℃, 118 ℃, 120 ℃, 122 ℃, 125 ℃, 128 ℃, or 130 ℃, but is not limited to the values recited, and other values not recited in the range are equally applicable.

Preferably, the stirring speed of the silica gel and silicone oil mixture is 200 to 500rpm/min, for example, 200rpm/min, 220rpm/min, 250rpm/min, 280rpm/min, 300rpm/min, 320rpm/min, 350rpm/min, 380rpm/min, 400rpm/min, 420rpm/min, 450rpm/min, 480rpm/min or 500rpm/min, but not limited to the values listed, and other non-listed values within the range of values are equally applicable.

The silica gel is preferably added in an amount of 80 to 100 parts, for example, 80 parts, 82 parts, 85 parts, 90 parts, 92 parts, 95 parts, 98 parts or 100 parts, but the present invention is not limited to the recited values, and other non-recited values within the range are equally applicable.

Preferably, the viscosity of the silica gel is 15000 to 40000mpa·s, and may be 15000mpa·s, 20000mpa·s, 25000mpa·s, 30000mpa·s, 35000mpa·s, or 40000mpa·s, for example, but the viscosity is not limited to the above-mentioned values, and other values not mentioned in the above-mentioned value range are similarly applicable.

The silicone oil is preferably added in an amount of 5 to 10 parts, for example, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts or 10 parts, but the silicone oil is not limited to the recited values, and other non-recited values within the range are equally applicable.

The viscosity of the silicone oil is preferably 100 to 400mpa·s, and may be, for example, 100mpa·s, 150mpa·s, 200mpa·s, 250mpa·s, 300mpa·s, 350mpa·s, or 400mpa·s, but the viscosity is not limited to the values recited, and other values not recited in the range are applicable.

Preferably, additives are also added during the dispersion treatment.

Preferably, the additive comprises nano calcium carbonate or white carbon black.

Preferably, the dispersion treatment is performed under stirring conditions.

The dispersing treatment is preferably carried out for a period of time of 1 to 2 hours, and may be, for example, 1 hour, 1.2 hours, 1.4 hours, 1.6 hours, 1.8 hours or 2 hours, but is not limited to the recited values, and other non-recited values within the range of values are equally applicable.

The stirring speed of the dispersion treatment is preferably 200 to 500rpm/min, and may be, for example, 200rpm/min, 220rpm/min, 250rpm/min, 280rpm/min, 300rpm/min, 320rpm/min, 350rpm/min, 380rpm/min, 400rpm/min, 420rpm/min, 450rpm/min, 480rpm/min or 500rpm/min, but not limited to the values listed, and other values not listed in the range of values are equally applicable.

In the invention, stirring paddles or a power mixer are adopted for stirring in the dispersing treatment process.

The temperature of the dispersion treatment is preferably 100 to 130 ℃, and may be, for example, 100 ℃, 102 ℃, 105 ℃, 108 ℃, 110 ℃, 112 ℃, 115 ℃, 118 ℃, 120 ℃, 122 ℃, 125 ℃, 128 ℃, or 130 ℃, but is not limited to the values listed, and other values not listed in the range are equally applicable.

The additive is preferably added in an amount of 80 to 150 parts, for example, 80 parts, 90 parts, 100 parts, 110 parts, 120 parts, 130 parts, 140 parts or 150 parts, but is not limited to the recited values, and other non-recited values within the range are equally applicable.

Preferably, the nano zinc oxide is added in an amount of 0.5 to 2wt%, for example, 0.5wt%, 0.7wt%, 0.9wt%, 1.1wt%, 1.3wt%, 1.5wt%, 1.7wt%, 1.9wt% or 2wt%, based on 100wt% of the vulcanized silicone rubber injection molding material, but not limited to the recited values, and other non-recited values within the range of values are equally applicable.

The invention limits the addition amount of nano zinc oxide to 0.5-2 wt%, when the addition amount is lower than 0.5wt%, the thermal stability of the vulcanized silicone rubber cannot be obviously improved, because the addition amount of nano zinc oxide is too low, the terminal silicon hydroxyl of the silicone rubber cannot be fully wrapped, the movement of a polymer molecular chain cannot be limited, and thus the unbuckling degradation reaction and hydrolysis reaction caused by the terminal hydroxyl of the silicone rubber cannot be inhibited; when the addition amount is more than 2wt%, the elasticity of the vulcanized silicone rubber is reduced, which is disadvantageous for injection molding in the subsequent process of preparing the membrane electrode.

Preferably, the nano titanium dioxide is added in an amount of 0.1 to 3wt%, for example, 0.1wt%, 0.3wt%, 0.5wt%, 0.8wt%, 1wt%, 1.2wt%, 1.5wt%, 1.7wt%, 2wt%, 2.2wt%, 2.5wt%, 2.7wt% or 3wt%, based on 100wt% of the vulcanized silicone rubber injection molding material, but is not limited to the recited values, and other non-recited values within the range of values are equally applicable.

The invention limits the addition of nano titanium dioxide to 0.1-3 wt%, when the addition is lower than 0.1wt%, the acid resistance of the vulcanized silicone rubber cannot be improved, because the addition of nano titanium dioxide is too small and cannot be uniformly dispersed in the vulcanized silicone rubber, the acid resistance of the vulcanized silicone rubber cannot be effectively improved; when the amount is more than 3wt%, the elasticity of the vulcanized silicone rubber is reduced, which is disadvantageous for injection molding in the subsequent process of preparing the membrane electrode.

Preferably, the dehydration treatment is performed under stirring conditions.

The stirring speed of the dehydration treatment is preferably 50 to 120rpm/min, and may be, for example, 50rpm/min, 60rpm/min, 70rpm/min, 80rpm/min, 90rpm/min, 100rpm/min, 110rpm/min or 1200rpm/min, but the stirring speed is not limited to the above-mentioned values, and other values not mentioned in the above-mentioned range are equally applicable.

The temperature of the dehydration treatment is preferably 100 to 130 ℃, and may be, for example, 100 ℃, 102 ℃, 105 ℃, 108 ℃, 110 ℃, 112 ℃, 115 ℃, 118 ℃, 120 ℃, 122 ℃, 125 ℃, 128 ℃, or 130 ℃, but is not limited to the values listed, and other values not listed in the range are equally applicable.

The time of the dehydration treatment is preferably 1.5 to 3 hours, and may be, for example, 1.5 hours, 1.7 hours, 1.9 hours, 2.1 hours, 2.3 hours, 2.5 hours, 2.7 hours, 2.9 hours or 3 hours, but is not limited to the recited values, and other non-recited values within the range of values are equally applicable.

In the invention, the stirring rotation speed is reduced to 50-120 rpm/min, and a vacuum valve is opened to carry out dehydration treatment.

As a preferred embodiment of the present invention, the crosslinking agent comprises any one or a combination of at least two of methyltributyloxy silane, vinyltributylketoxime silane, triallyl isocyanurate, vinyltriethoxysilane, alkoxysilane compound, and alkoxysilane compound partial hydrolysis polycondensate.

Preferably, the binder is mixed with the cross-linking agent under stirring.

The temperature at which the binder and the crosslinking agent are mixed is preferably 20 to 30 ℃, and may be, for example, 20 ℃, 21 ℃, 22 ℃, 23 ℃, 24 ℃, 25 ℃, 26 ℃, 27 ℃, 28 ℃, 29 ℃ or 30 ℃, but is not limited to the values recited, and other values not recited in the range are equally applicable.

Preferably, the binder is mixed with the crosslinking agent for a period of time ranging from 10 to 20 minutes, for example, 10 minutes, 11 minutes, 12 minutes, 13 minutes, 14 minutes, 15 minutes, 16 minutes, 17 minutes, 18 minutes, 19 minutes, or 20 minutes, but the present invention is not limited to the recited values, and other values not recited in the range of values are equally applicable.

Preferably, the stirring speed of the mixture of the binder and the crosslinking agent is 50 to 120rpm/min, for example, 50rpm/min, 60rpm/min, 70rpm/min, 80rpm/min, 90rpm/min, 100rpm/min, 110rpm/min or 1200rpm/min, but the stirring speed is not limited to the recited values, and other non-recited values within the range of the recited values are equally applicable.

The amount of the crosslinking agent added is preferably 3 to 7 parts, and may be, for example, 3 parts, 3.5 parts, 4 parts, 4.5 parts, 5 parts, 5.5 parts, 6 parts, 6.5 parts or 7 parts, but is not limited to the recited values, and other non-recited values within the range are equally applicable.

Preferably, the binder is mixed with the crosslinking agent under vacuum.

Preferably, the process of the reaction in step (2) is carried out under stirring conditions;

preferably, a coupling agent is also added during the reaction in step (2).

Preferably, the coupling agent comprises any one or a combination of at least two of KH-550, KH-560, KH-570, KH-792, DL-602 or DL-171.

Preferably, the vulcanizing agent comprises any one or a combination of at least two of DCP, HC-6, H-850, H-101 or HC-750.

The coupling agent is preferably added in an amount of 1 to 3 parts, for example, 1 part, 1.2 parts, 1.5 parts, 1.8 parts, 2 parts, 2.3 parts, 2.5 parts, 2.8 parts or 3 parts, but is not limited to the recited values, and other non-recited values within the range of values are equally applicable.

The vulcanizing agent is preferably added in an amount of 1 to 5 parts, for example, 1 part, 1.5 parts, 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts, 4.5 parts or 5 parts, but the amount is not limited to the recited values, and other non-recited values within the range are equally applicable.

Preferably, the process of the reaction in step (2) is carried out under vacuum.

Preferably, the reaction in step (2) is carried out under stirring.

Preferably, the reaction time in the step (2) is 10 to 30min, for example, 10min, 12min, 14min, 16min, 18min, 20min, 22min, 24min, 26min, 28min or 30min, but not limited to the recited values, and other non-recited values within the range are equally applicable.

Preferably, the stirring speed of the reaction in the step (2) is 200 to 500rpm/min, for example, 200rpm/min, 220rpm/min, 250rpm/min, 280rpm/min, 300rpm/min, 320rpm/min, 350rpm/min, 380rpm/min, 400rpm/min, 420rpm/min, 450rpm/min, 480rpm/min or 500rpm/min, but not limited to the values listed, and other non-listed values within the range of values are equally applicable.

The reaction temperature in the step (2) is preferably 20 to 30 ℃, and may be, for example, 20 ℃, 21 ℃, 22 ℃, 23 ℃, 24 ℃, 25 ℃, 26 ℃, 27 ℃, 28 ℃, 29 ℃ or 30 ℃, but is not limited to the values listed, and other values not listed in the range are equally applicable.

Preferably, in the step (2), after the reaction process is finished, a catalyst is further added to perform stirring reaction to obtain the vulcanized silicone rubber injection molding material.

Preferably, the catalyst comprises any one or a combination of at least two of dibutyltin dilaurate, kat245 or an organotitanium compound.

Preferably, after the catalyst is added, the reaction is stirred under vacuum.

Preferably, the catalyst is stirred for 20 to 40 minutes, for example, 20 minutes, 22 minutes, 24 minutes, 26 minutes, 28 minutes, 30 minutes, 32 minutes, 34 minutes, 36 minutes, 38 minutes or 40 minutes, but the catalyst is not limited to the recited values, and other non-recited values within the range are applicable.

The rotation speed of the catalyst for stirring reaction is preferably 200 to 500rpm/min, and may be, for example, 200rpm/min, 220rpm/min, 250rpm/min, 280rpm/min, 300rpm/min, 320rpm/min, 350rpm/min, 380rpm/min, 400rpm/min, 420rpm/min, 450rpm/min, 480rpm/min or 500rpm/min, but not limited to the values listed, and other values not listed in the range of values are equally applicable.

The temperature at which the catalyst is stirred is preferably 20 to 30 ℃, and may be, for example, 20 ℃, 21 ℃, 22 ℃, 23 ℃, 24 ℃, 25 ℃, 26 ℃, 27 ℃, 28 ℃, 29 ℃ or 30 ℃, but is not limited to the values recited, and other values not recited in the range are equally applicable.

The catalyst is preferably added in an amount of 0.1 to 0.7 part, for example, 0.1 part, 0.2 part, 0.3 part, 0.4 part, 0.5 part, 0.6 part or 0.7 part, but is not limited to the recited values, and other non-recited values within the range are equally applicable.

Preferably, the mass fraction of the catalyst is 0.1 to 1wt%, for example, 0.1wt%, 0.2wt%, 0.3wt%, 0.4wt%, 0.5wt%, 0.6wt%, 0.7wt%, 0.8wt%, 0.9wt% or 1wt%, but is not limited to the recited values, and other non-recited values within the range are equally applicable.

As a preferable technical scheme of the invention, the preparation method comprises the following steps:

(1) Mixing 80-100 parts of silica gel with the viscosity of 15000-40000 mPas with 5-10 parts of silicone oil with the viscosity of 100-400 mPas for 30-60 min at the temperature of 100-130 ℃ at the rotating speed of 200-500 rpm/min;

(2) Adding nano zinc oxide, nano titanium dioxide and an additive into the mixture obtained in the step (1) at the rotating speed of 200-500 rpm/min and the temperature of 100-130 ℃ for stirring and dispersing treatment for 1-2 h, wherein the adding amount of the additive is 80-150 parts, the adding amount of the nano zinc oxide is 0.5-2 wt% and the adding amount of the nano titanium dioxide is 0.1-3 wt% based on 100wt% of the vulcanized silicone rubber injection molding material, and then reducing the stirring speed to 50-120 rmp/min, and dehydrating the mixture obtained in the step (2) for 1.5-3 h at the temperature of 100-130 ℃ to obtain a base material;

(3) Adding 3-7 parts of cross-linking agent into the base material obtained in the step (2), stirring and mixing at the rotating speed of 50-120 rpm/min and the temperature of 20-30 ℃ under vacuum condition for 10-20 min, then adding 1-3 parts of coupling agent and 1-5 parts of vulcanizing agent, and reacting at the rotating speed of 200-500 rpm/min and the temperature of 20-30 ℃ under vacuum condition for 10-30 min;

(4) Adding 0.1-0.7 part of catalyst with mass fraction of 0.1-1 wt% into the mixture obtained in the step (3), and stirring and reacting at the rotation speed of 200-500 rpm/min and the temperature of 20-30 ℃ under vacuum condition for 20-40 min to obtain the vulcanized silicone rubber injection molding material.

In the invention, the preparation process of the vulcanized silicone rubber injection molding material is carried out in a dust-free environment.

In a second aspect, the invention provides a vulcanized silicone rubber injection molding material, which is prepared by the preparation method in the first aspect.

In a third aspect, the invention provides an integrated sealing membrane electrode, which comprises a proton exchange membrane, and a cathode and an anode on two sides of the proton exchange membrane, wherein a cathode elastomer sealing frame is arranged around the cathode, an anode elastomer sealing frame is arranged around the anode, the cathode elastomer sealing frame and the anode elastomer sealing frame are asymmetrically arranged, and the anode, the proton exchange membrane and the cathode are sealed into a whole through the anode elastomer sealing frame and the cathode elastomer sealing frame.

The anode elastomer sealing frame and the cathode elastomer sealing frame are both prepared from the vulcanized silicone rubber injection molding material in the second aspect.

The anode elastic sealing frame and the cathode elastic sealing frame are in a shape of a Chinese character 'hui', and only cover the periphery of the anode and the cathode respectively, so that the anode, the proton exchange membrane and the cathode are sealed into a whole, and the middle areas of the surfaces of the anode and the cathode are exposed.

According to the invention, the elastomer sealing frame of the membrane electrode in the fuel cell for the vehicle is prepared by adopting the vulcanized silicone rubber injection molding material provided by the second aspect, so that the elastomer sealing frame can be ensured to have excellent tolerance under the high-humidity and high-temperature and acidic battery working environment, the main chain of the vulcanized silicone rubber can be effectively prevented from being damaged under the high-humidity and high-temperature and acidic environment, and the precipitated silicon ions damage the proton exchange membrane and the catalyst layer, thereby improving the durability and the stability of the membrane electrode, and further prolonging the service life of the fuel cell for the commercial vehicle.

In addition, the cathode elastomer sealing frame and the anode elastomer sealing frame adopt asymmetric designs, so that water generated by a cathode can be effectively discharged in time, and the cathode elastomer sealing frame is prevented from being separated from a cathode gas diffusion layer in a high-humidity and hot environment to influence the air tightness of a membrane electrode.

The integral sealing membrane electrode provided by the invention is 1.2A/cm ² Under the current density, the voltage decay is only 5% after 3000 hours of operation, and compared with the traditional membrane electrode, the voltage decay is improved by 7% in durability.

As a preferable embodiment of the present invention, the cathode includes a cathode catalyst layer and a cathode gas diffusion layer sequentially laminated from the surface of the proton exchange membrane.

Preferably, the anode includes an anode catalyst layer and an anode gas diffusion layer sequentially laminated from a surface of the proton exchange membrane.

Preferably, the width of the cathode elastomer sealing frame covering the edge of the cathode gas diffusion layer is 0.05 to 3mm, for example, 0.05mm, 0.1mm, 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm or 3mm, but not limited to the recited values, and other non-recited values within the range of values are equally applicable.

Preferably, the width of the anode elastomer sealing frame covering the edge of the anode gas diffusion layer is 0.05 to 3mm, for example, 0.05mm, 0.1mm, 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm or 3mm, but not limited to the recited values, and other non-recited values within the range of values are equally applicable.

In the invention, the cathode elastomer sealing frame and the anode elastomer sealing frame are subjected to edge locking design, so that the membrane electrode can not leak gas or blow-by gas during working, and part of the membrane electrode is wrapped in an elastomer frame formed by the cathode elastomer sealing frame and the anode elastomer sealing frame.

Preferably, the contact area between the cathode elastomer seal frame and the surface of the cathode gas diffusion layer is S ₁ The contact area between the anode elastomer sealing frame and the surface of the anode gas diffusion layer is S ₂ Wherein S is ₁ ＞S ₂ 。

In the present invention, the contact area refers to the coverage area of the cathode elastomer seal frame on the surface of the cathode gas diffusion layer or the coverage area of the anode elastomer seal frame on the surface of the anode gas diffusion layer. The contact area of the cathode elastomer sealing frame and the cathode gas diffusion layer is larger than that of the anode elastomer sealing frame and the anode gas diffusion layer, and the cathode is accompanied with the generation of water in the reaction process, so that the contact area of the cathode elastomer sealing frame and the cathode gas diffusion layer is larger, and the separation of the cathode elastomer sealing frame and the cathode gas diffusion layer in a high-humidity and hot environment can be prevented, and the air tightness is influenced.

Preferably, the cathode elastomer sealing frame is 0.1 to 2mm higher than the cathode gas diffusion layer, for example, 0.1mm, 0.12mm, 0.14mm, 0.16mm, 0.18mm, 1mm, 1.2mm, 1.4mm, 1.6mm, 1.8mm or 2mm, but not limited to the recited values, and other non-recited values within the range of values are equally applicable.

Preferably, the anode elastomer sealing frame is 0.1-2 mm higher than the anode gas diffusion layer; for example, the range may be 0.1mm, 0.12mm, 0.14mm, 0.16mm, 0.18mm, 1mm, 1.2mm, 1.4mm, 1.6mm, 1.8mm or 2mm, but the range is not limited to the recited values, and other values not recited in the range are equally applicable.

Preferably, the thickness of the cathode elastomer seal frame is denoted as H ₁ The thickness of the anode elastomer sealing frame is recorded as H ₂ Wherein H is ₁ ＜H ₂ 。

In the invention, the thickness of the cathode elastomer sealing frame is smaller, because the thinner cathode elastomer sealing frame can rapidly discharge water generated by the cathode, and prevent the water from staying and gathering.

In the invention, a cathode plate is arranged on one side of the cathode gas diffusion layer far away from the cathode catalyst layer, an anode plate is arranged on one side of the anode gas diffusion layer far away from the anode catalyst layer, and a convex sealing strip and a gas conveying channel for sealing the cathode plate and the anode plate are respectively arranged at two ends of the cathode elastomer sealing frame and the anode elastomer sealing frame.

Preferably, the area of the proton exchange membrane is denoted as S ₃ The area of the catalyst layer is denoted as S ₄ The area of the diffusion layer is denoted as S ₅ Wherein S is ₃ ＞S ₄ ＝S ₅ 。

The area of the proton exchange membrane is limited to be larger than the areas of the catalyst layer and the diffusion layer, so that the diffusion layers on two sides of the proton exchange membrane are prevented from contacting to cause short circuit. In addition, the areas of the catalyst layer and the diffusion layer should be larger than the active area of the membrane electrode.

In a fourth aspect, the present invention provides a method for preparing the integrated sealing membrane electrode according to the third aspect, the method comprising:

And stacking the anode, the proton exchange membrane and the cathode in sequence, placing the anode, the proton exchange membrane and the cathode in an injection mold, and then injecting a vulcanized silicone rubber injection molding material into the injection mold to form an elastomer sealing frame, and curing to obtain the integrated sealing membrane electrode.

In the invention, an anode gas diffusion layer, an anode catalyst layer, a proton exchange membrane, a cathode catalyst layer and a cathode gas diffusion layer are sequentially stacked and placed in an injection mold. In addition, the preparation process of the integrated sealing membrane electrode is carried out in a dust-free environment. Meanwhile, the preparation method of the integrated sealing membrane electrode provided by the invention is simple and convenient to operate, reduces the influence of a large number of human factors on the preparation of the integrated membrane electrode, improves the quality and consistency of the membrane electrode, has fast production takt, reduces the labor input cost and improves the working efficiency

In a preferred embodiment of the present invention, the injection mold is preheated to 70 to 140 ℃, and then the injection material is injected into the injection mold, for example, 70 ℃, 80 ℃, 90 ℃, 100 ℃, 110 ℃, 120 ℃, 130 ℃, or 140 ℃, but the injection material is not limited to the above-mentioned values, and other values not shown in the above-mentioned value range are equally applicable.

In the invention, the device for preheating the injection mold can be an oven, a muffle furnace or an infrared heating device.

Preferably, the curing time is 5 to 10min, for example, 5min, 6min, 7min, 8min, 9min or 10min, but not limited to the recited values, and other non-recited values within the range are equally applicable.

Preferably, after the solidification, the die sinking and trimming treatment are sequentially carried out, so that the integrated sealing membrane electrode is obtained.

According to the invention, after the integrated sealing membrane electrode is taken out of the injection mold, redundant pouring gates, risers and burrs are trimmed and removed, and the integrated sealing membrane electrode finished product is obtained.

In a fifth aspect, the present invention provides a fuel cell comprising an integrated sealing membrane electrode according to the third aspect.

Compared with the prior art, the invention has the beneficial effects that:

(1) The invention obviously improves the tolerance of the vulcanized silicone rubber injection molding material under high humidity, high temperature and acid environment by adding the auxiliary agent, and is suitable for being used as the injection molding material of the membrane electrode in the fuel cell of the commercial vehicle;

(2) The elastic sealing frame of the membrane electrode in the fuel cell for the vehicle is prepared by adopting the vulcanized silicone rubber injection molding material provided by the invention, so that the main chain of the vulcanized silicone rubber is effectively prevented from being damaged under high-humidity and high-temperature acidic working environments, and the precipitated silicon ions damage the proton exchange membrane and the catalyst layer, thereby improving the durability and the stability of the membrane electrode and further prolonging the service life of the fuel cell for the commercial vehicle;

(3) According to the invention, the cathode elastomer sealing frame and the anode elastomer sealing frame are in asymmetric design, so that water generated by a cathode can be timely and effectively discharged, the cathode elastomer sealing frame is prevented from being separated from a cathode gas diffusion layer in a high-humidity and hot environment, the air tightness is influenced, and the stability and the service life of a fuel cell of a commercial vehicle are further improved.

Drawings

Fig. 1 is a schematic cross-sectional view of an integrated sealing membrane electrode according to an embodiment of the present invention.

Fig. 2 is a schematic structural view of an anode gas diffusion layer and an anode elastic sealing frame according to an embodiment of the present invention.

Fig. 3 is a schematic structural diagram of a cathode gas diffusion layer and a cathode elastic sealing frame according to an embodiment of the invention.

FIG. 4 is a graph showing the tensile strength of the vulcanized silicone rubber materials provided in example 1 and comparative example 1 over time at a temperature of 90℃and an environmental condition of pH 2.

Wherein, 1-proton exchange membrane; 2-an anode catalyst layer; 3-an anode gas diffusion layer; 4-an anode elastomer seal frame; 5-anode plate; 6-a cathode catalyst layer; 7-a cathode gas diffusion layer; 8-a cathode elastomer seal frame; 9-cathode plate.

Detailed Description

It is to be understood that in the description of the present invention, the terms "center", "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate orientations or positional relationships based on the drawings, are merely for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus are not to be construed as limiting the present invention. Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first", "a second", etc. may explicitly or implicitly include one or more such feature. In the description of the present invention, unless otherwise indicated, the meaning of "a plurality" is two or more.

It should be noted that, in the description of the present invention, unless explicitly specified and limited otherwise, the terms "disposed," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art in a specific case.

The technical scheme of the invention is further described below by the specific embodiments with reference to the accompanying drawings.

In a specific embodiment, as shown in fig. 1, the integrated sealing membrane electrode provided by the invention comprises a proton exchange membrane 1, and a cathode and an anode at two sides of the proton exchange membrane 1, wherein a cathode elastomer sealing frame 8 is arranged at the periphery of the cathode, an anode elastomer sealing frame 4 is arranged at the periphery of the anode, the cathode elastomer sealing frame 8 and the anode elastomer sealing frame 4 are asymmetrically arranged, and the anode, the proton exchange membrane 1 and the cathode are sealed into a whole through the anode elastomer sealing frame 4 and the cathode elastomer sealing frame 8. The anode elastomer sealing frame 4 and the cathode elastomer sealing frame 8 are both prepared from vulcanized silicone rubber injection molding materials.

Further, the cathode includes a cathode catalyst layer 6 and a cathode gas diffusion layer 7 sequentially laminated from the surface of the proton exchange membrane 1; the anode comprises an anode catalyst layer 2 and an anode gas diffusion layer 3 which are sequentially laminated from the surface of the proton exchange membrane 1.

In the invention, the cathode elastomer sealing frame 8 and the anode elastomer sealing frame 4 are subjected to edge locking design, so that the membrane electrode can not leak gas and blow-by gas in working, and part of the membrane electrode is wrapped in an elastomer frame formed by the cathode elastomer sealing frame 8 and the anode elastomer sealing frame 4.

Further, as shown in fig. 2 and 3, the contact area of the cathode elastomer seal frame 8 and the cathode gas diffusion layer 7 is denoted as S ₁ The contact area between the anode elastomer seal frame 4 and the anode gas diffusion layer 3 is denoted as S ₂ Wherein S is ₁ ＞S ₂ The method comprises the steps of carrying out a first treatment on the surface of the The thickness of the cathode elastomer seal frame 8 is denoted as H ₁ The thickness of the anode elastomer seal frame 4 is denoted as H ₂ Wherein H is ₁ ＜H ₂ 。

In the invention, a cathode plate 9 is arranged on one side of the cathode gas diffusion layer 7 far away from the cathode catalyst layer 6, an anode plate 5 is arranged on one side of the anode gas diffusion layer 3 far away from the anode catalyst layer 2, and a convex sealing strip and a gas conveying channel for sealing the cathode plate 9 and the anode plate 5 are respectively designed at two ends of the cathode elastomer sealing frame 8 and the anode elastomer sealing frame 4.

Further, the cathode catalyst layer 6 and the anode catalyst layer 2 are collectively referred to as a catalyst layer, the cathode gas diffusion layer 7 and the anode gas diffusion layer 3 are collectively referred to as a diffusion layer, and the area of the proton exchange membrane 1 is denoted as S ₃ The area of the catalyst layer is denoted as S ₄ The area of the diffusion layer is denoted as S ₅ Wherein S is ₃ ＞S ₄ ＝S ₅ 。

Example 1

The embodiment provides a preparation method of a vulcanized silicone rubber injection molding material, which comprises the following steps:

(1) Mixing 80 parts of alpha, omega-dihydroxypolydimethylsiloxane having a viscosity of 15000 mPas with 5 parts of methylsilicone oil having a viscosity of 100 mPas at a rotational speed of 500rpm/min and a temperature of 100 ℃ for 30 min;

(2) Adding nano zinc oxide, nano titanium dioxide and nano calcium carbonate into the mixture obtained in the step (1) at the rotating speed of 500rpm/min and the temperature of 100 ℃ for stirring and dispersing treatment for 1h, wherein the adding amount of the nano calcium carbonate is 80 parts, and the adding amount of the nano zinc oxide is 0.5wt% and the adding amount of the titanium dioxide is 0.1wt% based on the mass fraction of the vulcanized silicone rubber injection molding material of 100wt%, then reducing the stirring rate to 120rmp/min, and carrying out dehydration treatment on the mixture obtained in the step (2) for 1.5h at the temperature of 100 ℃ to obtain a base material;

(3) Adding 3 parts of methyltributylketone oxime silane into the base material obtained in the step (2), stirring and mixing at the rotation speed of 120rpm/min and the temperature of 20 ℃ under vacuum condition for 10min, then adding 1 part of KH550 and 1 part of DCP, and reacting at the rotation speed of 500rpm/min and the temperature of 20 ℃ under vacuum condition for 10min;

(4) And (3) adding 0.1 part of dibutyltin dilaurate with the mass fraction of 0.1wt% into the mixture obtained in the step (3), and carrying out stirring reaction for 20min at the rotation speed of 500rpm/min and the temperature of 20 ℃ under the vacuum condition to obtain the vulcanized silicone rubber injection molding material.

Based on the integrated sealing membrane electrode provided in the specific embodiment and the vulcanized silicone rubber injection molding material prepared in this embodiment, this embodiment further provides a preparation method of the integrated sealing membrane electrode, where the preparation method includes:

sequentially stacking the anode gas diffusion layer 3, the anode catalyst layer 2, the proton exchange membrane 1, the cathode catalyst layer 6 and the cathode gas diffusion layer 7 in an injection mold, preheating the injection mold to 70 ℃, injecting a vulcanized silicone rubber injection molding material into the injection mold to form an anode elastomer sealing frame 4 and a cathode elastomer sealing frame 8, curing for 10min, and sequentially carrying out mold opening and trimming treatment to obtain an integrated sealing membrane electrode; the height of the anode elastomer sealing frame 4 higher than the anode gas diffusion layer 3 in the integrated sealing membrane electrode is 2mm, and the width of the anode elastomer sealing frame 4 covering the edge of the anode gas diffusion layer 3 is 0.05mm; the height of the cathode elastomer sealing frame 8 above the cathode gas diffusion layer 7 is 0.1mm, and the width of the cathode elastomer sealing frame 8 covering the edge of the cathode gas diffusion layer 7 is 3mm.

Example 2

(1) Stirring and mixing 100 parts of polymethylsiloxane with the viscosity of 40000 mPas and 10 parts of ethyl silicone oil with the viscosity of 400 mPas for 60min at the temperature of 130 ℃ at the rotation speed of 500 rpm/min;

(2) Adding nano zinc oxide, nano titanium dioxide and white carbon black into the mixture obtained in the step (1) at the rotating speed of 500rpm/min and the temperature of 130 ℃ for 2 hours, stirring and mixing, wherein the adding amount of the white carbon black is 150 parts, the adding amount of the nano zinc oxide is 2wt% and the adding amount of the titanium dioxide is 3wt% based on the mass fraction of the vulcanized silicone rubber injection molding material of 100wt%, then reducing the stirring speed to 50rmp/min, and dehydrating the mixture obtained in the step (2) at the temperature of 130 ℃ for 3 hours to obtain a base material;

(3) Adding 7 parts of vinyl tributyl ketoxime silane into the base material obtained in the step (2), stirring and mixing at the rotation speed of 50rpm/min and the temperature of 30 ℃ under vacuum condition for 20min, then adding 3 parts of KH560 and 5 parts of HC-6, and reacting at the rotation speed of 200rpm/min and the temperature of 30 ℃ under vacuum condition for 30min;

(4) Adding 0.7 part of Kat245 with the mass fraction of 1wt% into the mixture obtained in the step (3), and carrying out stirring reaction for 40min at the temperature of 30 ℃ under the condition of 200rpm/min, thereby obtaining the vulcanized silicone rubber injection molding material.

sequentially stacking the anode gas diffusion layer 3, the anode catalyst layer 2, the proton exchange membrane 1, the cathode catalyst layer 6 and the cathode gas diffusion layer 7 in an injection mold, preheating the injection mold to 140 ℃, injecting a vulcanized silicone rubber injection molding material into the injection mold to form an anode elastomer sealing frame 4 and a cathode elastomer sealing frame 8, curing for 5min, and sequentially carrying out mold opening and trimming treatment to obtain an integrated sealing membrane electrode; the height of the anode elastomer sealing frame 4 higher than the anode gas diffusion layer 3 in the integrated sealing membrane electrode is 1mm, and the width of the anode elastomer sealing frame 4 covering the edge of the anode gas diffusion layer 3 is 1mm; the height of the cathode elastomer seal frame 8 above the cathode gas diffusion layer 7 was 0.5mm, and the width of the cathode elastomer seal frame 8 covering the edge of the cathode gas diffusion layer 7 was 2mm.

Example 3

(1) 90 parts of alpha, omega-dihydroxypolydimethylsiloxane having a viscosity of 30000 mPas are mixed with 7 parts of methylethoxy silicone oil having a viscosity of 300 mPas for 40min at a rotational speed of 300rpm/min and a temperature of 120 ℃;

(2) Adding nano zinc oxide, nano titanium dioxide and nano calcium carbonate into the mixture obtained in the step (1) at the rotating speed of 300rpm/min and the temperature of 120 ℃ for stirring and dispersing treatment for 1.5 hours, wherein the adding amount of the nano calcium carbonate is 130 parts, and the adding amount of the nano zinc oxide is 1wt% and the adding amount of the titanium dioxide is 2wt% based on the mass fraction of the vulcanized silicone rubber injection molding material of 100wt%, then reducing the stirring speed to 70rmp/min, and carrying out dehydration treatment on the mixture obtained in the step (2) for 1.5 hours at the temperature of 120 ℃ to obtain a base material;

(3) Adding 5 parts of triallyl isocyanurate into the base material obtained in the step (2), stirring and mixing at the rotation speed of 70rpm/min and the temperature of 25 ℃ under vacuum condition for 15min, then adding 3 parts of KH570 and 2 parts of H-850, and reacting at the rotation speed of 300rpm/min and the temperature of 25 ℃ under vacuum condition for 15min;

(4) And (3) adding 0.5 part of dibutyltin dilaurate with the mass fraction of 0.5% into the mixture obtained in the step (3), and carrying out stirring reaction for 25min at the rotation speed of 300rpm/min and the temperature of 25 ℃ under the vacuum condition to obtain the vulcanized silicone rubber injection molding material.

sequentially stacking the anode gas diffusion layer 3, the anode catalyst layer 2, the proton exchange membrane 1, the cathode catalyst layer 6 and the cathode gas diffusion layer 7 in an injection mold, preheating the injection mold to 110 ℃, injecting a vulcanized silicone rubber injection molding material into the injection mold to form an anode elastomer sealing frame 4 and a cathode elastomer sealing frame 8, curing for 7min, and sequentially carrying out mold opening and trimming treatment to obtain an integrated sealing membrane electrode; the height of the anode elastomer sealing frame 4 higher than the anode gas diffusion layer 3 in the integrated sealing membrane electrode is 1.5mm, and the width of the anode elastomer sealing frame 4 covering the edge of the anode gas diffusion layer 3 is 1.5mm; the height of the cathode elastomer seal frame 8 above the cathode gas diffusion layer 7 was 0.2mm, and the width of the cathode elastomer seal frame 8 covering the edge of the cathode gas diffusion layer 7 was 2.5mm.

Example 4

This embodiment differs from embodiment 1 in that: the nano zinc oxide in the step (2) was added in an amount of 0.3wt% and the remaining process parameters and operation steps were the same as in example 1.

Example 5

This embodiment differs from embodiment 1 in that: the amount of nano zinc oxide added in the step (2) was 2.5wt%, and the other process parameters and operation steps were the same as those of example 1.

Example 6

This embodiment differs from embodiment 1 in that: the amount of nano titanium dioxide added in the step (2) was 0.05wt%, and the remaining process parameters and operation steps were the same as those of example 1.

Example 7

This embodiment differs from embodiment 1 in that: the amount of nano titanium dioxide added in the step (2) was 3.5wt%, and the remaining process parameters and operation steps were the same as in example 1.

Example 8

This embodiment differs from embodiment 1 in that: the cathode elastomer sealing frame 8 in the integrated sealing membrane electrode is 2mm higher than the cathode gas diffusion layer 7, the width of the cathode elastomer sealing frame 8 covering the edge of the cathode gas diffusion layer 7 is 0.05mm, and the other process parameters and operation steps are the same as those of the embodiment 1.

Example 9

This embodiment differs from embodiment 1 in that: the height of the cathode elastomer sealing frame 8 above the cathode gas diffusion layer 7 in the integrated sealing membrane electrode was 2mm, and the other process parameters and operation steps were the same as in example 1.

Example 10

This embodiment differs from embodiment 1 in that: the width of the cathode elastomer sealing frame 8 covering the edge of the cathode gas diffusion layer 7 in the integrated sealing membrane electrode is 0.05mm, and the rest of the process parameters and operation steps are the same as those of the embodiment 1.

Comparative example 1

The present comparative example provides a method for producing an integrated sealing membrane electrode, comprising:

commercially available vulcanized silicone rubber materials are adopted as the materials of the anode elastomer sealing frame 4 and the cathode elastomer sealing frame 8; sequentially stacking the anode gas diffusion layer 3, the anode catalyst layer 2, the proton exchange membrane 1, the cathode catalyst layer 6 and the cathode gas diffusion layer 7 in an injection mold, preheating the injection mold to 70 ℃, injecting a commercially available vulcanized silicone rubber material into the injection mold to form an anode elastomer sealing frame 4 and a cathode elastomer sealing frame 8, curing for 10min, and sequentially performing mold opening and trimming treatment to obtain an integrated sealing membrane electrode; the height of the anode elastomer sealing frame 4 higher than the anode gas diffusion layer 3 in the integrated sealing membrane electrode is 2mm, and the width of the anode elastomer sealing frame 4 covering the edge of the anode gas diffusion layer 3 is 0.05mm; the height of the cathode elastomer seal frame 8 above the cathode gas diffusion layer 7 was 2mm, and the width of the cathode elastomer seal frame 8 covering the edge of the cathode gas diffusion layer 7 was 0.05mm.

Comparative example 2

The difference between this comparative example and example 1 is that: the step of adding nano zinc oxide is omitted in the step (2), the adding amount of the nano zinc oxide is distributed to the rest components according to the formula proportion of the vulcanized silicone rubber injection molding material, and the rest process parameters and operation steps are the same as those of the embodiment 1.

Comparative example 3

The difference between this comparative example and example 1 is that: the step of adding nano titanium dioxide is omitted in the step (2), the adding amount of nano zinc oxide titanium dioxide is distributed to the rest components according to the formula proportion of the vulcanized silicone rubber injection molding material, and the rest process parameters and operation steps are the same as those of the example 1.

Comparative example 4

The difference between this comparative example and example 1 is that: the step of adding nano zinc oxide and nano titanium dioxide is omitted in the step (2), the total addition amount of the nano zinc oxide and the nano titanium dioxide is distributed to the rest components according to the formula proportion of the vulcanized silicone rubber injection molding material, and the rest process parameters and operation steps are the same as those of the example 1.

The membrane electrodes prepared in examples 1 to 10 and comparative examples 1 to 4 were subjected to cell testing, and the test results are shown in table 1; the vulcanized silicone rubber materials in example 1 and comparative example 1 were subjected to tensile strength test, and the test results are shown in fig. 4.

TABLE 1

From the data analysis of table 1:

(1) The membrane electrode in examples 1-3 has excellent stability and durability, which shows that the elastomer sealing frame of the membrane electrode is prepared by adopting the silicon sulfide injection molding material provided by the invention, and the cathode elastomer sealing frame 8 and the anode elastomer sealing frame 4 adopt asymmetric designs, so that the damage of a main chain of the silicon sulfide rubber in a high-humidity and high-temperature acidic battery working environment can be effectively avoided, and the precipitated silicon ions damage the proton exchange membrane 1 and the catalyst layer, thereby improving the durability and the stability of the membrane electrode and further prolonging the service life of a fuel cell of a commercial vehicle.

(2) The stability and durability of the membrane electrode in examples 4 and 5 are lower than those in example 1, because the amount of nano zinc oxide added in example 4 is too low and that in example 5 is too high. When the addition amount of the nano zinc oxide is too low, the silicon hydroxyl at the tail end of the silicon rubber cannot be fully wrapped, and the movement of a polymer molecular chain cannot be limited, so that the unbuckled degradation reaction and the hydrolysis reaction caused by the silicon rubber terminal hydroxyl cannot be inhibited; when the addition amount of the nano zinc oxide is too high, the elasticity of the vulcanized silicone rubber is reduced, and the injection molding is not facilitated in the subsequent membrane electrode preparation process.

(3) The stability and durability of the membrane electrode in examples 6 and 7 were lower than those in example 1, because the amount of nano titania added in example 6 was too low and that in example 7 was too high. When the addition amount of the nano titanium dioxide is too low, the nano titanium dioxide cannot be uniformly dispersed in the vulcanized silicone rubber, so that the acid resistance of the vulcanized silicone rubber cannot be effectively improved; when the addition amount of the nano titanium dioxide is too high, the elasticity of the vulcanized silicone rubber is reduced, and the injection molding is not facilitated in the subsequent membrane electrode preparation process.

(4) The stability and durability of the membrane electrode in example 8 are lower than those of example 1, because the cathode elastomer seal frame 8 and the anode elastomer seal frame 4 in example 8 are symmetrically designed, water generated from the cathode cannot be discharged timely and effectively, and separation of the cathode elastomer seal frame 8 from the cathode gas diffusion layer 7 under a high humidity and heat environment cannot be effectively avoided. Therefore, the membrane electrode has poor air tightness, and low durability and stability.

(5) The stability and durability of the membrane electrode in examples 9 and 10 are lower than those in example 1, because the cathode elastomer seal frame 8 in example 9 is thick and the water generated at the cathode cannot be rapidly discharged; in example 10, the contact area between the cathode elastomer seal frame 8 and the surface of the cathode gas diffusion layer 7 was small, and separation of the cathode elastomer seal frame 8 and the cathode gas diffusion layer 7 in a high-humidity and hot working environment could not be prevented, which could affect the gas tightness of the membrane electrode.

(6) The stability and durability of the membrane electrode in comparative example 1 are much lower than those of example 1, since the anode and cathode elastomer seal frames 4 and 8 of the membrane electrode were prepared using commercially available vulcanized silicone rubber materials in comparative example 1, and the cathode and anode elastomer seal frames 8 and 4 were designed symmetrically. The commercial vulcanized silicone rubber material has poor tolerance to high-temperature high-humidity and acidic working environments, and precipitated silicon ions damage the proton exchange membrane 1 and the catalyst layer, so that the durability and the stability of the membrane electrode are poor; and the symmetrical injection molding design of the anode and the cathode cannot effectively ensure the air tightness of the membrane electrode. Therefore, the membrane electrode in comparative example 1 cannot meet the requirements of commercial vehicle fuel cells for sealability and life enhancement.

Further, the change with time of the tensile strength in the environment of ph=2 at the temperature of 90 ℃ was tested for the vulcanized silicone rubber injection molding material provided in example 1 of the present invention and the commercial vulcanized silicone rubber material provided in comparative example 1, and as shown in fig. 4, the tensile strength of the commercial vulcanized silicone rubber material exhibited a significant decrease trend, while the change in the tensile strength of the vulcanized silicone rubber injection molding material provided in example 1 tended to be smooth. The silicon sulfide rubber injection molding material provided by the invention has excellent heat resistance, moisture resistance and acid resistance, and can meet the requirement of commercial vehicle fuel cells on tightness when being used as a membrane cell elastomer sealing frame material.

(7) The stability and durability of the membrane electrodes in comparative examples 2 to 4 are much lower than that of example 1, because no nano zinc oxide auxiliary agent was added in comparative example 2, no titanium dioxide auxiliary agent was added in comparative example 3, and no nano zinc oxide and nano titanium dioxide auxiliary agent were added in comparative example 4, when preparing the vulcanized silicone rubber injection molding material. The nano zinc oxide auxiliary agent can improve the stability of the vulcanized silicone rubber injection molding material in a high-humidity high-heat environment, and the nano titanium dioxide auxiliary agent can improve the stability of the vulcanized silicone rubber injection molding material in an acidic condition. Therefore, when the vulcanized silicone rubber injection molding material prepared by adding the nano zinc oxide and the nano titanium dioxide simultaneously is used as the elastomer material of the membrane electrode, the requirements of the commercial vehicle fuel cell on the stability and the durability of the membrane electrode can be met.

The applicant declares that the above is only a specific embodiment of the present invention, but the scope of the present invention is not limited thereto, and it should be apparent to those skilled in the art that any changes or substitutions that are easily conceivable within the technical scope of the present invention disclosed by the present invention fall within the scope of the present invention and the disclosure.

Claims

1. A method for preparing a vulcanized silicone rubber injection molding material, which is characterized by comprising the following steps:

(1) Mixing silica gel and silicone oil, adding an auxiliary agent, and then sequentially carrying out dispersion treatment and dehydration treatment to obtain a base material;

(2) Mixing the base material obtained in the step (1) with a cross-linking agent, and then adding a vulcanizing agent to react to obtain the vulcanized silicone rubber injection molding material;

the addition amount of the silica gel is 80-100 parts;

the viscosity of the silica gel is 15000-40000 mPa.s;

the addition amount of the silicone oil is 5-10 parts;

the viscosity of the silicone oil is 100-400 mPa.s; the auxiliary agent comprises nano zinc oxide and nano titanium dioxide;

the addition amount of the nano zinc oxide is 0.5-2 wt% based on the mass fraction of the vulcanized silicone rubber injection molding material being 100 wt%;

the addition amount of the nano titanium dioxide is 0.1-3 wt% based on the mass fraction of the vulcanized silicone rubber injection molding material being 100 wt%;

An additive is also added in the dispersing treatment process;

the additive comprises nano calcium carbonate or white carbon black;

the addition amount of the additive is 80-150 parts.

2. The method of claim 1, wherein the silica gel comprises an α, ω -dihydroxy polydimethylsiloxane.

3. The method of claim 1, wherein the silica gel is a hydroxyl-terminated polydimethylsiloxane.

4. The method according to claim 1, wherein the silicone oil comprises any one or a combination of at least two of methyl silicone oil, ethyl silicone oil, phenyl silicone oil, methyl hydrogen-containing silicone oil, methyl phenyl silicone oil, methyl chlorophenyl silicone oil, methyl ethoxy silicone oil, methyl trifluoropropyl silicone oil, and methyl vinyl silicone oil.

5. The preparation method according to claim 1, wherein the silica gel and the silicone oil are mixed under stirring.

6. The preparation method according to claim 1, wherein the silica gel and the silicone oil are mixed for 30 to 60 minutes.

7. The preparation method according to claim 1, wherein the temperature at which the silica gel and the silicone oil are mixed is 100 to 130 ℃.

8. The method according to claim 1, wherein the stirring speed of mixing the silica gel and the silicone oil is 200 to 500rpm/min.

9. The method according to claim 1, wherein the dispersion treatment is performed under stirring.

10. The method according to claim 1, wherein the time of the dispersion treatment is 1 to 2 hours.

11. The method according to claim 1, wherein the stirring speed of the dispersion treatment is 200 to 500rpm/min.

12. The method according to claim 1, wherein the temperature of the dispersion treatment is 100 to 130 ℃.

13. The production method according to claim 1, wherein the dehydration treatment is performed under stirring.

14. The method according to claim 1, wherein the stirring speed of the dehydration treatment is 50 to 120rpm/min.

15. The method according to claim 1, wherein the dehydration treatment is carried out at a temperature of 100 to 130 ℃.

16. The method according to claim 1, wherein the dehydration treatment is performed for 1.5 to 3 hours.

17. The method of claim 1, wherein the cross-linking agent comprises any one or a combination of at least two of methyltributyloxy silane, vinyltributylketoxime silane, triallyl isocyanurate, alkoxysilane compound, or alkoxysilane compound partial hydrolysis polycondensate.

18. The method of claim 1, wherein the base material and the crosslinking agent are mixed under stirring.

19. The method of claim 1, wherein the temperature at which the base material is mixed with the cross-linking agent is 20-30 ℃.

20. The method of claim 1, wherein the binder is mixed with the cross-linking agent for a period of 10 to 20 minutes.

21. The method according to claim 1, wherein the stirring speed of mixing the base material with the crosslinking agent is 50 to 120rpm/min.

22. The method according to claim 1, wherein the crosslinking agent is added in an amount of 3 to 7 parts.

23. The method of claim 1, wherein the base material is mixed with the crosslinking agent under vacuum.

24. The process according to claim 1, wherein the reaction in step (2) is carried out under stirring.

25. The process according to claim 1, wherein a coupling agent is further added during the reaction in step (2).

26. The method of claim 25, wherein the coupling agent comprises any one or a combination of at least two of KH-550, KH-560, KH-570, KH-792, DL-602, or DL-171.

27. The method of claim 1, wherein the vulcanizing agent comprises any one or a combination of at least two of DCP, HC-6, H-850, H-101, or HC-750.

28. The method of claim 25, wherein the coupling agent is added in an amount of 1 to 3 parts.

29. The method according to claim 1, wherein the vulcanizing agent is added in an amount of 1 to 5 parts.

30. The method according to claim 1, wherein the reaction in step (2) is carried out under vacuum.

31. The method according to claim 1, wherein the reaction time in the step (2) is 10 to 30 minutes.

32. The process according to claim 1, wherein the stirring speed of the reaction in step (2) is 200 to 500rpm/min.

33. The process according to claim 1, wherein the temperature of the reaction in step (2) is 20 to 30 ℃.

34. The preparation method according to claim 1, wherein in the step (2), after the reaction process is finished, a catalyst is further added to perform a stirring reaction to obtain the vulcanized silicone rubber injection molding material.

35. The method of claim 34, wherein the catalyst comprises any one or a combination of at least two of dibutyltin dilaurate, kat245, or an organotitanium compound.

36. The process of claim 34 wherein the catalyst is added and the reaction is carried out under vacuum with stirring.

37. The method of claim 34, wherein the catalyst is stirred for a period of 20 to 40 minutes.

38. The method of claim 34, wherein the catalyst is stirred at a speed of 200 to 500rpm/min.

39. The process of claim 34 wherein the catalyst is stirred at a temperature of 20 to 30 ℃.

40. The method of claim 34, wherein the catalyst is added in an amount of 0.1 to 0.7 parts.

41. The preparation method according to claim 34, wherein the mass fraction of the catalyst is 0.1 to 1wt%.

42. The preparation method according to claim 1, characterized in that the preparation method comprises:

43. A vulcanized silicone rubber injection molding material, characterized in that the vulcanized silicone rubber injection molding material is prepared by the preparation method of any one of claims 1-42.

44. The integrated sealing membrane electrode is characterized by comprising a proton exchange membrane, a cathode and an anode, wherein the cathode and the anode are arranged on two sides of the proton exchange membrane, a cathode elastomer sealing frame is arranged on the periphery of the cathode, an anode elastomer sealing frame is arranged on the periphery of the anode, the cathode elastomer sealing frame and the anode elastomer sealing frame are asymmetrically arranged, and the anode, the proton exchange membrane and the cathode are sealed into a whole through the anode elastomer sealing frame and the cathode elastomer sealing frame;

the anode elastomer sealing frame and the cathode elastomer sealing frame are prepared from the vulcanized silicone rubber injection molding material according to claim 43.

45. The integrated sealed membrane electrode according to claim 44, wherein the cathode comprises a cathode catalyst layer and a cathode gas diffusion layer sequentially laminated from a surface of the proton exchange membrane;

the anode comprises an anode catalyst layer and an anode gas diffusion layer which are sequentially laminated on the surface of the proton exchange membrane.

46. The integrally sealed membrane electrode of claim 45 wherein said cathode elastomeric seal frame has a width of 0.05-3 mm covering said cathode gas diffusion layer rim.

47. The integrally sealed membrane electrode of claim 45 wherein said anode elastomeric seal frame has a width of 0.05-3 mm covering said anode gas diffusion layer rim.

48. The integrally sealed membrane electrode of claim 45 wherein the contact area of said cathode elastomeric seal frame with said cathode gas diffusion layer surface is S ₁ The contact area between the anode elastomer sealing frame and the surface of the anode gas diffusion layer is S ₂ Wherein S is ₁ ＞S ₂ 。

49. The integrally sealed membrane electrode of claim 45 wherein said cathode elastomeric seal frame is 0.1-2 mm above said cathode gas diffusion layer.

50. The integrally sealed membrane electrode of claim 45 wherein said anode elastomer sealing frame is 0.1-2 mm above said anode gas diffusion layer.

51. The integrally sealed membrane electrode of claim 44 wherein said cathode elastomeric seal frame has a thickness denoted as H ₁ The thickness of the anode elastomer sealing frame is recorded as H ₂ Wherein H is ₁ ＜H ₂ 。

52. The integrated sealed membrane electrode of claim 45 wherein the cathode catalyzes the process ofThe catalyst layer and the anode catalyst layer are collectively called as a catalyst layer, the cathode gas diffusion layer and the anode gas diffusion layer are collectively called as a diffusion layer, and the area of the proton exchange membrane is denoted as S ₃ The area of the catalyst layer is denoted as S ₄ The area of the diffusion layer is denoted as S ₅ Wherein S is ₃ ＞S ₄ ＝S ₅ 。

53. A method of making an integrated sealed membrane electrode according to any one of claims 44-52, comprising:

and stacking the anode, the proton exchange membrane and the cathode in sequence, placing the layers in an injection mold, and then injecting a vulcanized silicone rubber injection molding material into the injection mold to form an anode elastomer sealing frame and a cathode elastomer sealing frame, and curing to obtain the integrated sealing membrane electrode.

54. The method of claim 53, wherein the injection mold is preheated to 70-140 ℃ and then injection molding material is injected into the injection mold.

55. The process of claim 53 wherein the curing is for a period of time ranging from 5 to 10 minutes.

56. The method of claim 53, wherein after the curing, the mold opening and trimming are further performed sequentially to obtain the integrated sealing membrane electrode.

57. A fuel cell comprising an integrated sealed membrane electrode according to any one of claims 44 to 52.