TWI267222B - New process for fabricating the membrane electrode assembly of fuel cells - Google Patents

Abstract

This invention relates to a kind of fabricating method of fuel cells. The characteristics of this process are using porous and thin material as a support layer, then coating step by step with anode side catalytic slurry, electrolyte slurry and cathode side catalytic slurry. Therefore, a three-in-one type of membrane electrode assembly can be obtained.

Description

1267222 IX. Description of the invention: [Technical field to which the invention pertains] The present invention relates to a method for manufacturing a fuel cell, which is characterized in that a porous thin substrate is used, which comprises an anode catalyst layer slurry, an electrolyte layer slurry, and a cathode. The continuous coating process of the catalyst layer slurry can be used to prepare a three-in-one membrane electrode assembly (MEA 'Membrane Electrode Assembly).

[Prior Art] A battery is a chemical reaction between a fuel (such as hydrogen or a hydrogen-rich gas, an alcohol, a hydrocarbon) and an oxidant (such as air or oxygen) to convert chemical energy into DC energy. Heat and the electrochemical device of his reactants. Because fuel cells have the advantages of low noise, low vibration, high efficiency, fast start-up and long life, they are ideal for generator/transport vehicles and portable power packs. A currently developing fuel cell can be classified into an alkali liquid type (AFC), a phosphoric acid type molten carbon type (MCFC), a solid oxide type (SOFC), and a polymer electrolyte membrane type depending on the electrolyte used. . In recent years, the development of the sub-electrolyte membrane type has been most valued. This type of battery can be reused as a proton exchange membrane type (PEMFC) or a direct methanol type (Dmf). The former uses the fuel system, and the Gong or 3 has a large helium gas. Recombinant gas, and the latter two use an aqueous solution. In addition, the fuel cell can also be reverse operated as a water electrolysis device. In this case, a special catalyst and material must be used to regenerate the fuel cell that can be designed for both electrolysis and power generation. (RFC) 乂 逆 reverse 5 1267222 In addition to the above fuel cell types, there is still a fuel cell (MFC), the anode is made of metal such as rhodium, magnesium or aluminum, and the air electrode is still used, and the electrolyte is brine or hydroxide. Potassium-specific solution, which can form a power supply device for button-type batteries for hearing aid power supply." If widely used, 2„_lower' will be used in several applications, in series or in parallel.

The battery pack has the shape shown in Figure 1. In addition to the single battery 1〇dJ group of components still includes the bipolar plate 110 and

130, conductive plates 140 and 15, end plates (10) and two H and fixing screws 180 and gas joints 1 90. The unit battery is the basic unit that constitutes the entire battery pack, and the basin structure is composed of seven layers, as shown in Figure 2. Taking pemfc as an example, the intermediate layer of the single cell has an electrolyte action 101, the anode fish cathode catalyst layers 102 and 103 having a thickness of about 2 〇μηι on both sides, and the lower side is a low-porosity, drainage gas diffusion layer 1 〇4 and 1〇5, 泄, the shim layers 1〇6 and 107, a total of seven layers. The father, the film 101 plus the anode and cathode catalyst layers 1〇2 and 1〇3 are called the three-in-one type membrane electrode assembly, and if the anode and the side gas are added, the diffusion layers 104 and 105 are called The five-in-one type single battery, if added to the anode and cathode sides of the gasket layer 1: 1 07 is called a seven-in-one type unit battery. The seven-in-one type single battery can be combined with the hydrogen and air guiding electrodes 110 and 1 20, and a plurality of such battery cells can be stacked in series or in parallel to form a battery pack, and the cooling plate 130 must be installed. With 140 to ensure stable operation. , a general proton exchange membrane fuel cell mostly uses DuPont's proton exchange membrane Nafion as an electrolyte layer, although ^

1267222 Sex, chemistry and proton conductivity are all desirable, but it is easy to expand and deform the aqueous solvent, which makes it difficult to directly coat the catalyst slurry. The technology of the membrane electrode assembly is focused on the catalyst layer. Coating method. For detailed fuel cell manufacturing methods and structures, reference may be made to numerous domestic and foreign patents, such as U.S. Patent Nos. 4,683,828, 5,252,410, 5,399,184, 5,523,177, 5,547,551, 5,559,961, 5,723,173, 5,723,228, 5,869,201, 6,01,6,6 6, 6, 475, 249, etc. According to the description of the aforementioned patent, the diffusion layer coating method is most widely used, and the catalyst slurry is directly coated on the anode and the slain slave paper or carbon cloth, and then hot pressed with the Nafion film. The amount is not easy to reduce 'The development of the transfer method, the /, water; bucket directly coated on the Tef | 〇n transfer paper, and then use the two sides of the squeezing film 'but will encounter Nafjon film must be pre-transformed, after transfer The rate is not easy to improve and other issues. 66 古彳i come to zh to directly apply the catalyst slurry to Nafl〇n film. Its disadvantages: dry or wet method's but can be applied to small-scale products; wet type can be made by J, more, Moreover, the gland of the waste solvent Ly* ^ ^ af 丨ο π > valley> night 'genus ^ 2 media aggregate coated on the sides of the Tenon film into a complex porous film filling operation, then; first = cloth, the process is more complicated Need, therefore need:::: 枓 coating technology. And Jin developed a new process and 7 1267222 [Summary of the Invention] The focus of the present invention is to develop a new type of polar group process technology, the method used is:

The principle of Hit and gas layer coating, that is, a membrane electrode assembly in which a porous substrate is connected to an anode catalyst layer, an electrolyte layer and a cathode catalyst. If the gas diffusion layer on both sides of the anode and cathode is further pressed, a five-in-one type unit can be formed, and if the cathode and anode layers are further pressed or coated, a seven-in-one unit cell can be fabricated. . Such a process disk i is obviously different from the conventional method, and has a multi-point, j-point, 0 jin. Therefore, the main purpose of the present invention is to provide an easy-to-process fuel cell manufacturing method, which can be continuously and in large quantities. "Battery battery" to overcome the bottleneck of mass production of fuel cell commercialization. Another purpose of this month is to provide a fuel cell manufacturing method that reduces material cost, and a low-cost porous meson exchange function can replace high-priced Commercial ion exchange membranes are now available. Another object of the present invention is to provide a process for reducing the number of defects = a battery manufacturing method that utilizes continuous coating and drying processes and steps to accelerate the production of fuel cells. Another object of the present invention is to provide a fuel cell structure having a good structure which improves the cracking or unevenness of the surface of the catalyst layer after coating and shaping of the catalyst layer. Moreover, the contact between the catalyst layer and the electrolyte layer is good, and the reaction g property can be improved. 0. Another object of the present invention is to provide a fuel cell manufacturing method capable of effectively controlling the coating thickness of the 1267222 electrolyte layer and the catalyst layer. Effectively control the amount of catalyst applied. Another object of the present invention is to provide a fuel cell manufacturing method having excellent inverse performance, which can improve the contact between the catalyst layer and the electrolytic shell layer to improve the power generation performance of the fuel cell.

/ For the fuel cell manufacturing method to achieve the above objectives, firstly, it is necessary to select a suitable porous substrate, including strength, porosity, electrical insulation, heat resistance, acid and alkali resistance, service life, and reasonable price. The substrates that can be tested include a variety of polymer films of ft, glass fiber cloth, and metal oxides. For example, the Teflon film is stretched and stretched, or the cloth woven into the fiber has a diameter of 3〇-5.微% porosity of the micro-library, as well as woven glass fiber cloth, also has enough pores to accommodate the electrolyte. The choice of the solution must take into account factors such as ion conductivity, pore = ft, dryness and heat resistance, and is related to the desired battery. For example, in the case of pemfc and dmfc, a solution of 5-ΐ5%_〇η can be used, which can be in the form of a fruit; in the case of AFC and MFC, an alkaline aqueous solution of $0-3-35%, if the water absorption of the substrate

It needs to be blended with a thickener such as CMC. /The choice of catalyst slurry, in pEMFC, DMFC phantom V brother, often use Pt or Pt / Ru as a catalyst. The composition of the catalyst slurry coated on the surface of the electrolyte layer with Pt - 2 (% P Pt) powder, Naf 丨 0n solution (5 wt 〇 / o) 3, · ^ ^. The ratio of each component is pt/c: DryNafion = (#梦士,里11), ethylene glycol: Naf丨〇n solution = 1 : 1 a shell). , the preparation method of the catalyst slurry is to first grind pt/c 9 1267222 powder particles into ethylene glycol, and slowly add in the stirring.

The Nafion solution is then slurried by ultrasonic vibration or high-speed agitation. In general, the gas diffusion layer for fuel cells is mostly used for coating or carbon paper. The thickness, porosity, strong sound, second degree and conductivity are required. For example, T曰ray II J = product. As for the material for the leakage preventing gasket layer of the fuel cell, there are Silicon, Teflon, Viton, and the like. If it is manufactured by reference processing, it is necessary to select the viscosity and dryness of the thermophilic product; if it is changed to the pressing method, then g g 2 is pre-processed or cut into solid products. ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, First, the substrate 200 is solidified, and a conventional method such as a roller, a brush, a spray coating, or the like is applied to one side of the substrate 2〇0. Attached to the flat plate, in the continuous performance of the Shanghai, by the four weeks with the glue ▼ sticky fixed to carry the house # 4,, Wang Zhong, can be stretched by the reel machine after the first coating process, 201 to finalize. ^ / ^ sequence, in order to coat the coated catalyst layer as in the previous "material = the second in the shift range can be heated in the range of 105-1 paper temperature in the general screen printing process of a H, dry mode can also use the first The road is still hot and the light is dried. When the surface of the cloth is placed under the first cloth, the catalyst layer 201 will be coated, and then the pore shape of the tUd 200 is performed, that is, the electrolysis is temporarily performed, so that the electrolyte liquid slurry is discharged. The substrate is bonded to a substrate 210 that is filled with the slurry 10 222. The #ϊΐί coating procedure is carried out by coating the cathode catalyst layer 202 with a paste, and then applying the slurry to the substrate 210. ~a 2 3 Γ dry process, the cathode catalyst layer 202 is fixed to form these procedures, then the three-in-one type membrane electrode body can be obtained 3:: the lit cloth or carbon paper is attached to the membrane electrode group 2 2ΪΛ3 With the upper and lower two pieces not clamped, carry out, 00 pieces of hot pressing for 90 seconds, the hot machine can be used to make the five-in-one type unit battery. ^When hot pressing, the cut gasket is attached to both sides of the pole assembly, together with the carbon cloth or carbon paper of the diffusion layer: ??, ϋ can be made into a 7-in-1 unit battery. In addition, the five-in-one unit battery that is also pressed is placed on the dispenser table. The TefkH^smc〇n glue is applied to the battery side by using the dispensing paste, and then dried; then Teflon or Silicone coating is applied. The iron is also dried on the other side of the battery, so that it can also be made into a seven-in-one type unit. [Embodiment] The main use of the present invention is to manufacture a fuel film electrode assembly, and the method used is The anode catalyst layer, the electrolyte layer and the cathode catalyst layer are continuously coated on the porous substrate.

It is a three-in-one type membrane electrode assembly, and can be used to make five-two-one and seven-in-one unit batteries. Moutine I

The process steps of one embodiment of the present invention are as shown in the drawing. This is a three-in-one type film of a PEM fuel cell. The first step is to select a porous group. For example, the porosity is 50% and the thickness is about 25 // m stretch processing J 1267222

The Teflon film is then subjected to a cutting process of a Teflon film 320, for example, a substrate having a length of 5 cm and a width of 5 cm, which is preferably cut in the same direction as the Teflon film. After the cutting is completed, in order to maintain the cleanliness of the substrate, the cleaning operation can be performed, for example, immersed in a 5 wt_% H 2 〇 2 solution, heated to 70 ° C, and washed for one hour to remove the organic substances on the surface of the film, and then Wash 3 times with pure water. Then, it was immersed in 〇·5Μ H2SO4, heated to 70 ° C, and washed for one hour to remove the inorganic substances on the surface of the film, and then washed three times with pure water, and then dried at room temperature. Prior to the application of the anode catalyst layer, steps 323 and 325 for preparing and preparing the catalyst slurry are required, for example, using Pt/C (10% Pt) powder produced by Johnson Matthey, UK, 5 wt produced by DuPont. % Nafion solution and ethylene glycol, the preparation method is to first grind the Pt/C powder, add ethylene glycol to stir, slowly add the Nafion solution into the mixing, and finally make the slurry with a high-speed stirrer. The ratio of each component is Pt/C : Dry Nafion = 3 : 1 (by weight), ethylene glycol · Nafion solution = 1 : 1 (volume ratio). In this embodiment, the catalyst paste is printed onto the Tefl〇n film by screen printing, as in step 330. Since the Tefoln film is structural and does not deform, the catalyst layer can be directly printed. The method is to first fix the circumference of the Tefl〇n film on the screen printing substrate, and then place the frame type stencil with a pre-ordered hollow area of 3 cm X 3 cm on the Tef丨〇n film, the stencil The hollow part needs to be positioned and adjusted to the central part of the Tef|on film, and then the catalyst slurry is applied to the Teflon film through the hollow portion of the mesh plate with a rubber squeegee] that is, the central portion of the Teflon film has 3 cm X 3 cm The area of the catalyst slurry. Immediately after the coating was completed, the anode catalyst layer predrying procedure 340 was carried out, i.e., placed in an oven at 11 ° C for 10 minutes. ^ When applying the electrolyte layer to the Teflon film substrate, 12 1267222 is required to prepare the Nafion solution, as in step 345, here, the higher viscosity 15 wt% Nafion solution produced by Ion Power, USA is used. At the time of actual coating (step 350), this example uses the screen printing method as described above, but the hollow portion of the stencil is changed to 5 cm X 5 cm so that the pores of the entire Teflon film can be filled with the Nafion solution. As for the pre-drying step 360, it was placed in an oven and heated at 120 QC for 10 minutes. The coating and pre-drying steps 370 and 380 of the cathode catalyst layer are then carried out in the same manner as the anode catalyst layers 320 and 330. The fuel cell of this example is a PEMFC that uses helium to react with air. Therefore, both the cathode catalyst and the anode catalyst belong to the Pt/C series, so the same catalyst slurry can be used. The method comprises the steps of: tape-fixing the periphery of the Teflon film coated with the anode catalyst layer and the electrolyte layer on the screen printing substrate, and then using the frame of the hollow area of 3 cm X 3 cm for coating the anode catalyst layer. The stencil is placed on the Teflon membrane, and the hollow portion of the stencil needs to be positioned and adjusted to the central portion of the Teflon membrane, and then the catalyst slurry is applied to the Teflon membrane through the hollow portion of the stencil with a squeegee, that is, the Teflon membrane. The central part has a catalyst slurry of 3 cm X 3 cm area. Immediately after the coating was completed, the cathode catalyst layer predrying procedure 380 was carried out, and was also placed in an oven at 110 ° C for 10 minutes. After the above steps are completed, the Teflon film coated and pre-dried by the anode catalyst layer, the electrolyte layer and the cathode catalyst layer is completed, that is, the membrane electrode assembly MEA is completed. However, in order to enhance the robustness of the overall structure, that is, to prevent the catalyst layer from falling off during the subsequent operation, a final hot pressing drying step 390 is required, that is, two upper and lower Teflon having a thickness of about 3 mm are used. The plate was sandwiched between the membrane electrode assemblies and hot pressed at 130 GC and 3,000 psi of hot pressing for 60 seconds to complete the entire process. 13 1267222 The above embodiments are only examples for convenience of description, and the rights claimed in the present application are based on the scope of the patent application, and are not limited to the above embodiments. In summary, the manufacturing method of the fuel cell provided by this creation does have industrial use value, and the creation is the first creation, and the same or similar technology is not disclosed before or in any publication before the patent application. Therefore, the creation of the operation has been in conformity with the requirements of the invention patent, and the application for patent is filed according to law. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 shows the basic structure of a conventional fuel cell stack; Figure 2 shows the basic structure of a conventional single cell; Figure 3 shows the manufacturing process of the three-in-one battery module of the present invention; The four series show the manufacturing process of the three-in-one battery module body of the present invention; [Main component symbol description] 110 bipolar plate 130 cooling plate 150 conductive plate 170 end plate 190 gas joint 102 anode catalyst layer 104 gas diffusion layer 106 Leakage pad 100 Membrane electrode assembly 120 Bipolar plate 140 Conductive plate 160 End plate 180 Fixing screw 101 Proton exchange membrane 103 Cathode catalyst layer 105 Gas diffusion layer 14 1267222 107 Leakproof crucible 200 Porous substrate 201 Anode catalyst Layer 202 cathode catalyst layer 210 has completed electrolyte liquid slurry coating porous substrate 320 Teflon film cutting and cleaning 325 catalyst slurry preparation 340 anode catalyst layer drying 360 Teflon film drying 380 cathode catalyst layer drying 310 Teflon membrane selection

323 catalyst slurry preparation 330 anode catalyst layer coating 345 Nafion slurry preparation 350 Teflon film coating 370 cathode catalyst layer coating 390 membrane battery body drying

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Claims (1)

1267222 X. Patent Application Range: / 1. A method for manufacturing a fuel cell using a continuous coating for manufacturing a membrane electrode assembly of the fuel cell, the method comprising the steps of: a. selecting a porous group b. coating a catalyst electrode layer on the side of the porous substrate; c. applying an electrolyte slurry on the other side of the porous substrate to fill the pores of the substrate with the electrostatic slurry丨d_ Coating another layer of catalyst electrode layer on the same side of the substrate, and sandwiching the porous substrate with the electrolyte layer on the two layers of the catalyst electrode layer to complete the membrane electrode assembly of the fuel cell. 2. The fuel cell manufacturing method according to claim 1, wherein after the step d, the completed membrane electrode assembly is further subjected to a hot pressing treatment step to complete the durable membrane electrode assembly. The method for producing a fuel cell according to claim 1, wherein the porous substrate of the step a is a polymer film, a glass fiber cloth, a metal oxide thin plate or the like. The fuel cell manufacturing method according to claim 1, wherein the catalysts of steps b and d are Pt, Pt-Ru, Pt/C, Pt-Ru/C, Ag, Μη〇2, etc. Metal or metal oxide. 5. The method of manufacturing a fuel cell according to claim 1, wherein the electrolyte solution of step c is an aqueous solution or a polymer solution suitable for conducting anions or cations. 6. The fuel cell manufacturing method according to claim 1, wherein after step d, the two sides of the completed membrane electrode assembly are combined with a gas diffusion layer, and the completed five-in-one unit is completed. battery. The fuel cell manufacturing method according to claim 6, wherein the gas diffusion layer is a material such as carbon paper, carbon cloth or metal fiber. 8. The fuel cell manufacturing method according to claim 6, further comprising a seven-in-one type unit battery in which the two sides of the completed five-in-one unit battery are combined with a leakage preventing gasket layer. . 9. The fuel cell manufacturing method according to claim 8, wherein the leakage preventing gasket layer is a material such as Silicon, Teflon or Viton. 10. The fuel cell manufacturing method according to claim 1, which is applicable to alkali liquid type (AFC), phosphoric acid type (PAFC), proton exchange membrane type (PEMFC), direct methanol type (DMFC), direct ethanol. Fuel cells such as DEFC, reversible battery (RFC), and metal (MFC). 17