TWI657615B - Light-weight proton exchange membrane cell structure and method for manufacturing collectors of fuel cells - Google Patents

Abstract

In the present invention, a graphite thin film is applied to a current collector plate of a proton exchange membrane fuel cell to improve the corrosion resistance of the current collector plate, thereby maintaining the stability of the fuel cell's long-term operation. In an embodiment, in the process of manufacturing the current collector plate, a FR4 / Epoxy composite material is used as a base material, and a current collector layer and an anti-corrosion layer are formed on the surface. The current collector layer is coated with a copper film by a thermal evaporation method, and a graphite film is used as an anti-corrosion layer to improve the corrosion resistance. Other embodiments of the present invention provide three different methods, such as radio frequency magnetron sputtering, screen printing, and spin coating, to produce a graphite film anticorrosive layer for a current collector plate.

Description

Lightweight Proton Exchange Membrane Cell Structure and Fuel Cell Collection Manufacturing method of electric board

The invention relates to a fuel cell technology, in particular to a battery structure of a lightweight proton exchange membrane and a method for manufacturing a current collecting plate of a fuel cell.

(I) Development of micro fuel cells

In recent years, the development of portable electronic products has advanced by leaps and bounds, and related technologies have also been continuously innovated. For example, as notebook computers become thinner and lighter, they have also entered into tablet-type touch computers; mobile phones have evolved from traditional to smart phones; At the same time, due to the development of cloud technology, various communication software, online games and application software have been continuously developed and widely used in smart phones, tablet computers or notebook computers. As a result, people are increasingly diversifying in the use of portable electronic products, and users have been distributed across all ages and social classes. Relatively speaking, the dependence of humans on portable electronic products has gradually increased to become the majority Necessities in life or work, and the daily use time is gradually extended, that is, no matter at home, work, school, shopping, dining, etc., all kinds of portable electronic products will be brought. With portable electricity With the diversified development of sub-products, the long-term and replenishment of electricity has become very important. Therefore, companies have invested a lot of research and development to increase the capacity of secondary batteries and reduce their volume at the same time. However, when pursuing secondary batteries (such as lithium batteries) that are thin, short, and high-capacity, they may also cause the danger of spontaneous combustion or explosion of secondary batteries, and the safety of secondary batteries has attracted everyone's attention. When the secondary battery continues to develop, it will certainly reach its limit capacity, so it can be expected that using fuel cells as a charging device for portable electronic products and increasing its power generation capacity will be an important theme for future scientific and technological development and application. . Many electronics companies, especially Japanese companies, have launched portable fuel cell power generation systems that provide portable electronic devices such as notebook computers and mobile phones for charging, such as Sony, Toshiba, Hitachi, NEC, Fujikura, Yamaha, etc. The company, which is almost a well-known large company, has been committed to developing portable fuel cells.

The reason why fuel cells are valued is that they use electrochemical technology to directly convert fuel to electricity without the need for a combustion reaction, so they are not limited by the Carnot cycle, and there are no complicated mechanical components for generating electricity. At the same time, the fuel source is mainly Using hydrogen as an energy source, and its by-product is mainly water, so fuel cells have the advantages of high energy conversion efficiency, low pollution, low noise, and simple structure. In addition, the fuel cell itself is similar to a generator and is different from a secondary battery. Its active material does not exist in the body. It does not need to be charged and discharged, but only needs to be continuously replenished with the active material (fuel), that is, sustainable power generation. . For the development of micro-portable fuel cells, Direct Methanol Fuel Cell (DMFC) is an important technology. DMFC uses methanol aqueous solution instead of hydrogen, and can use ordinary solution tanks instead of high-pressure hydrogen storage bottles or storage tanks. Hydrogen alloy tanks are used to store fuel, so it has the advantage of being easy to store and carry fuel. It also eliminates many gas control valves, making the entire system simpler and lighter. Although there are many advantages mentioned above, compared with the Proton Exchange Membrane Fuel Cell (PEMFC) which generally uses hydrogen as fuel, the amount of catalyst required by DMFC is much higher, resulting in higher cost. In addition, since the poisoning of the catalyst platinum (Pt) intermediate product carbon monoxide (CO) during the electrochemical reaction must be avoided during the anode reaction, ruthenium (Ru) will be added to the catalyst to suppress the poisoning effect of CO, but it will also lead to power generation. Reduced effectiveness. During the DMFC reaction, carbon dioxide (CO ₂ ) is generated at the anode, and bubbles are formed in the methanol fuel aqueous solution, which easily causes blockage in the pipeline. Therefore, the removal of CO ₂ has become a considerable problem during the operation of the DMFC. Methanol also easily penetrates the proton exchange membrane from the anode to the cathode. This is a problem of methanol crossover, which reduces the efficiency of DMFC and poisons the cathode Pt catalyst. Therefore, it is often low concentration to enter the body of DMFC. The concentration of methanol aqueous solution is generally not higher than 10% vol. In terms of cathode products, due to the electrochemical reaction of DMFC, a larger amount of water is generated at the cathode, so avoiding flooding is also a place that requires special attention when the DMFC is operating. Therefore, although the DMFC system seems simple, the anode flow channel, cathode flow channel and air flow rate and flow rate must be properly designed and controlled, otherwise its performance and stability will be seriously affected. However, the operating voltage of a single-cell DMFC is often between 0.2V and 0.3V. To apply it to a portable charging device, many must be connected in series, and then the voltage is increased to 5V through a boost circuit before it can be applied. So there is considerable complexity and cost. Therefore, if miniaturized PEMFC is used, many of the above problems can be overcome. However, general PEMFCs are oriented towards high-power stacking and related applications, such as those used in vehicles or standby generators, and it is rarely discussed about low-power applications.

High-power fuel cells are usually stacked in an upright stack. The bipolar plate mode is used. One side is the cathode and the other is the anode. The membrane electrode group (Membrane Electrode Assembly, MEA), so stacked. The flow channel is integrated in the bipolar plate, the anode adopts a closed flow channel, and the cathode adopts a closed type (supply air by an air pump) or a side opening (a fan drives the air). However, such a stacking method is relatively bulky and is not suitable for micro fuel cells that only need to generate several watts of electricity. Therefore, the related design research of series connection of the fuel cell in a planar manner came into being. With this design, the cathode can also adopt a self-breathing design, eliminating the need for a fan or an air pump, and it is easy to design Thin and light fuel cell. Some microelectromechanical systems (MEMS) process technologies have also been applied to the fabrication of micro fuel cells. Lee et al. (Reference 1) proposed to change the fuel cell stacking method to a planar tandem stack, and introduced the micro-electro-mechanical process to the production of miniaturized fuel cells. The research showed that the planar stacking and MEMS process are applied to fuel cells. Feasibility. Cha et al. (Ref. 2) proposed a method of lifting metal in MEMS technology to make metal wires in DMFC in micro DMFC, which has the advantages of reducing the size of fuel cells and providing lower contact resistance. Lu et al. (Reference 3) proposed that a micro-electro-mechanical process is used to deposit metal materials on a wafer to make a collector sheet for a fuel cell, and then develop a micro fuel cell. Hsieh et al. (Ref. 4) used a yellow light development process to develop a specific pattern on a substrate, and The electromechanical process creates the conductive areas of the current collector. Yun et al. (Reference 5) proposed depositing a metal thin film on a current collector plate to reduce the impedance of the current collector plate, thereby improving battery performance. Karst et al. (Ref. 6) produced 47 micro fuel cells on a piece of silicon wafer using a micro-electromechanical process, cut one of them, and assembled it on an aluminum substrate. In addition, they also proposed to use the aperture ratio of the lid covering the cathode to effectively manage the water of the breathing micro fuel cell and avoid the phenomenon of water accumulation in the cathode. Omosebi and Besser (Ref. 7) used microfabrication technology to fabricate microchannels and catalyst layers on the proton exchange membrane, and performed performance tests to verify their feasibility. Alanis-Navarro et al. (Reference 8) used a sputtering method to deposit a copper thin film on acrylic (PMMA), so that PMMA can be metalized, and a micro fuel cell prototype was formed for performance testing. Chen et al. (Ref. 9) used MEMS technology to fabricate microfluidic channels on silicon substrates to form micro-hydrogen fuel cells, and discussed the effects of parameters on battery performance. The results of their research show that the conductive area and materials, The impact of micro fuel cell performance is most significant. Peng et al. (Ref. 10) integrated a nanometer dual-effect structure and used a silicon wafer as a substrate to produce a high-efficiency micro-hydrogen fuel cell. In addition, the article uses three methods to improve battery performance. The first method is integration. Nano and micro structures increase the reaction area; the second method is to coat the three-phase region with ultra-thin ions to reduce the oxygen diffusion resistance; the third method is to use micro-interlock (micro- interlocks) design to improve interface strength. Hsieh and Huang (Ref. 11) proposed a planar array module fuel cell stack. The main process is to use micro-electromechanical electroforming technology to fabricate micro-channels on a copper sheet substrate, and then stack and assemble the plane. Fuel cell stack and test. Lee and Kim (Reference 12) A Micro Space Power System for Nano Satellites (Nono-Satellites) is proposed. This system combines a fuel cell made with MEMS technology, including sodium borohydride and hydrogen peroxide. Hydrogen and oxygen generating devices, micro-pumps and micro-reactors have been studied and relevant experiments have been carried out to verify their feasibility. Wu et al. (Ref. 13) proposed a passive DMFC for pervaporation and fuel supply. The structure includes a polydimethylsiloxane (PDMS) active layer and a silicon support layer. It is novel, but the authors point out that their proposed micro DMFC can only operate in one direction at a time. Yang et al. (Ref. 14) used silicon as a substrate and applied MEMS technology to produce a current collector and runner plate. PDMS was used to support the support assembly structure. In this paper, the effect of four runner modes on efficiency was discussed.

(II) Printed-Circuit Board (PCB) manufacturing process

In the development of micro fuel cells, due to the need for light, thin and short designs, the components of their circuits and control circuits also need to be considered for their simplicity and small size without taking up space, and their applications are mainly to provide charging or power for portable electronic products. Therefore, the application of mature and widely-used printed-circuit board (PCB) technology in electronic products to the construction of micro fuel cells is also a subject that attracts considerable attention because this technology can Helps miniaturize micro fuel cells. The application of PCB to the fuel cell assembly technology can be traced back to 2003. It was proposed by the team of O'Hayre et al. (Ref. 15) and Schmitz et al. (Ref. 16) in the same year. O'Hayre et al. (Ref. 15) proposed a technology for making PEMFC by PCB, and mentioned that PCB has advantages such as mature, stable and reliable technology, design diversity, low cost, and light weight, which is quite suitable for application to micro fuel cells. Schmitz et al. (Refs. 16 and 17) proposed to use PCB technology to make a flat passive micro PEMFC with a thickness of only 3.5 mm. The research points out the advantages of the PCB process applied to micro fuel cells. In the stacking process of flat fuel cells, the series connection of fuel cells is very important. The PCB can be used to directly connect the circuits in series, eliminating complex physical circuits. Kim et al. (Ref. 18) further combined the MEMS process and used a flexible PCB as a current collector to produce a planar PEMFC battery pack with a battery volume of 18 cm ³ and a maximum power density of 350 mW. cm ^-2 . The main advantage of a fuel cell with a PCB is that it can break through many of the limitations of the traditional graphite process, making the fuel cell smaller and more diverse. The main concept of PCB is System on Module, which is based on the concept of the printed circuit board process. The perforated metal foil, glass fiber, PP (prepreg, prepreg), conductive circuit, etc. are first thermocompression bonded and separately Take out the anode and anode plates, and then heat-clamp the anode and anode plates, PP, MEA, and glass fiber. The metal foils on the anode and anode plates contact each CELL to export to the circuit side, and then use a PCB to design a similar In the channel conduction method, a hole is penetrated and then soldered, and the cathode and anode are used for circuit conduction. Each MEA and the current collector on the cathode and anode are connected by a hole in the PCB circuit on the cathode and anode to form a single cell. In this way, many CELLs can be placed in a very small space; when the batteries are connected in series or in parallel, the contacts on the cathode and anode plates of each single cell can be welded in series or parallel, or directly on the cathode and anode PCB boards. Design on the circuit can form a series-parallel effect to achieve the purpose of increasing the battery operating voltage. In the previous study (Reference 19), the inventor of this case put forward a description of the process of PCBDMFC, and discussed a series of researches on the damage caused by MEA in the process of PCB hot-pressing. The results of the study indicate that the hot pressing temperature that the MEA is subjected to during the PCB manufacturing process has a significant effect on its efficiency. The lower the temperature, the smaller the damage to the MEA. Therefore, if the temperature required for the PP to harden after melting is high, the MEA area needs to be locally cooled. In the structure of the planar battery pack of PCBDMFC, the opening mode of the current collector plate has a considerable influence on its efficiency, and a good opening arrangement mode will help improve the battery efficiency. Kuan et al. (References 20 to 22) systematically cut the space with fractal geometry, and conducted a series of discussions on the effect of the collector plate opening geometry on the efficiency. The results show that changing the cathode opening has a greater effect on efficiency than changing the anode opening. When the aperture ratio is small, the battery performance is low. At this time, increasing the battery aperture ratio will help improve the battery performance. Under the same aperture ratio, the longer the opening perimeter, the better the battery performance. Kuan et al. (Ref. 23) also proposed the flow path design of the flat DMFC with the CFD mixture model. In the research, the red ink experiment was used to verify the accuracy of the simulation, and then the flow path was designed by this method. The common flow passages for fuel in and out, equal-length split and three-dimensional through-collection point split and merge are proposed. Yuan et al. (Ref. 24) used a PCB to make a light-weight current collector plate and a disc-shaped passive DMFC module. The current collection area was a copper-clad aluminum sheet, and the surface was plated with gold to prevent corrosion.

(Three) fuel cell current collector plate / bipolar plate

General fuel cell bipolar plates / collector plates need to be considered in the design and production of the following: the more common bipolar plates contain a flow channel design, with the function of transmitting fuel supply and collecting electrons, membrane electrode group is Sandwiched between the two, electrons After the anode metal current collector is connected to the external circuit cathode to form a loop, electricity can be generated. At present, the main materials of common bipolar plates are classified into graphite-polymer composite current collector plates, metal current collector plates, and composite current collector plates. The power generated by a fuel cell needs to be output to the outside through the medium of a collector plate or a bipolar plate. Therefore, in general, a bipolar plate suitable for a proton exchange membrane fuel cell should have the following basic functions to improve battery performance : (1) Separate the oxidant from the reducing agent to avoid the effect of hydrogen crossover through the plate. (2) Excellent mechanical strength, enabling the bipolar plate to make balanced contact with the MEA to collect current. (3) Appropriate flow channel design enables the fuel to be evenly distributed into the Cell, which produces a uniform electrochemical reaction, and the product water can be taken away at the cathode to avoid the phenomenon of water accumulation, which leads to the reduction of battery efficiency. (4) Good heat conduction efficiency makes the temperature in the battery uniform, and can achieve heat dissipation and temperature control effects. (5) Excellent conductivity to collect current and output to external use. (6) The appropriate hole ratio of the electrode plate and the ratio of the groove area of the flow field to the total electrode area should have an appropriate ratio. If the hole opening is too high, the contact resistance of the MEA and the bipolar plate will be too high and the performance will be reduced. Too low openings will reduce the MEA catalyst utilization rate and the internal flow field resistance is too high, which will also reduce battery performance. (7) The bipolar plate should be made of low-density material to reduce the weight of the battery.

(4) Current collector board with PCB process in micro fuel cell

In the previous research by the inventor of this case, the FR4 / Epoxy composite material used in the PCB was used as the base material of the current collector plate, and the current collection area was made of metal foil. However, due to the large thermal expansion coefficient between the metal foil and the FR4 / Epoxy composite substrate, the electrochemical reaction during fuel cell operation is an exothermic reaction, and the internal temperature It will rise, so it will stop operating for a long time. Due to repeated thermal expansion and contraction effects, the adhesion between the current collector plate and the MEA may be reduced, and the contact resistance may be increased, thereby reducing the efficiency of the fuel cell. In addition, because the fuel cell will have moisture during the reaction, whether it is DMFC or PEMFC, the carbon cloth or carbon paper of the diffusion layer will absorb water and swell. At this time, the metal current collector sheet will be under pressure and may be slightly deformed for a long time. When it is running or stopped, it may also cause the connection between the current collector sheet and the MEA to decrease, and the efficiency of the fuel cell may decrease. Therefore, in the previous research of the inventor of this case, it was proposed to integrate the two, and the collector layer (copper) and anti-corrosion layer (nickel) were plated on the surface of the FR4 / Epoxy composite substrate by thermal evaporation method in MEMS to increase Its strength and stability.

(5) Corrosion resistance of current collector plate

When a current collector is fabricated by a MEMS or PCB manufacturing process, a metal layer is included for collecting / conducting. However, when PEMFC or DMFC reacts, it will show acidity. Under long-term operation, the metal layer is easily corroded, which will affect the conductivity / The current-collecting properties and the Pt catalyst are poisoned by metal ions precipitated due to corrosion, resulting in a decline in efficiency and a decline. Therefore, how to improve the corrosion resistance of the current collector is a key issue in the development of micro fuel cells. However, it is often difficult to balance the high conductivity and corrosion resistance of the current collector layer. How to achieve a balance is a very important part. The lightweight current collector plate proposed in the previous research by the inventor of this case is a thermally vapor-deposited copper film on the surface of the FR4 / EPOXY composite substrate as a conductive layer, and a corrosion-resistant layer is thermally vapor-deposited with a nickel film, but nickel is used as a corrosion resistance. The layer should be able to be further improved. There are also studies on coating metal surfaces with gold films to prevent corrosion and increase conductivity, but the cost of gold is very high, which reduces the competitiveness due to price increases during commercialization.

Therefore, how to improve the corrosion resistance of the miniature PEMFC current collector plate, so that the stability of performance can be maintained under long-term operation, so that it has commercial feasibility is an important problem to be solved in this technical field.

Literature list:

Literature 1: S.J. Lee et al., Design and fabrication of a micro fuel cell array with flip-flop interconnection, J. of Power Sources, Vol. 112, 2002, pp.410-418.

Literature 2: H.Y. Cha et al., Fabrication of all- polymer micro-DMFCs using UV-sensitive photoresist, Electrochimica Acta, Vol.50, 2004, pp.795-799.

Literature 3: G.Q. Lu et al., Development and characterization of a silicon-based micro direct methanol fuel cell, Electrochimica Acta, Vol49, 2004, pp.821-828.

Reference 4: S.S. Hsieh et al., Development and performance analysis of a H2 / air micro PEM fuel cell stack, J. of Power Sources, Vol. 163, 2006, pp. 440-449.

Reference 5: Y.-H. Yun, Deposition of gold-titanium and gold-nickel coatings on electropolished 316L stainless steel bipolar plates for proton exchange membrane fuel cells, International J. of Hydrogen Energy, Vol. 35 2010, pp.1713- 1718.

Reference 6: N. Karst et al., Innovative water management in micro air-breathing polymer electrolyte membrane fuel cells, J. of Power Sources, Vol. 195, 2010, pp. 1156-1162.

Reference 7: A. Omosebi and R. Besser, Fabrication and performance evaluation of an in-membrane micro-fuel cell, J. of Power Sources, Vol. 242, 2013, pp.272-276.

Reference 8: J. A. Alanis-Navarro et al., Fabrication and characterization of a micro-fuel cell made of metalized PMMA, J. of Power Sources, Vol. 242, 2013, pp.1-6.

Reference 9: C.-H. Chen et al., An experimental study on micro proton exchange membrane fuel cell, J. of Fuel Cell Science and Technology, Vol. 9, No. 3, 2011, pp. 031001-1-031001 -7.

Reference 10: H.-C. Peng et al., A high efficient micro-proton exchange membrane fuel cell by integrating micro-nano synergical structures, J. Power Sources, Vol. 225, 2013, pp. 277-285.

Reference 11: S.-S. Hsieh and C.-C. Huang, Design, fabrication and performance test of a planar array module-type micro fuel cell stack, Energy Conversion and Management, Vol. 76, 2013, pp.971- 979.

Reference 12: J. Lee and T. Kim, Micor space power system using MEMS fuel cell for nano-satellites, Acta Astronautica, Vol. 101, 2014 pp.165-169.

Reference 13: Z. Wu et al., A passive vapor-feed direct methanol fuel cell based on a composite pervaporation membrane, J. of Microelectromechanical systems, Vol. 24, No. 1, 2015, pp.207-215.

Reference 14: J. Yang et al., Influence of anode flow field on mass transport in a air-breathing micro direct methanol fuel cell, 2016 IEEE 11th Conference on Industrial Electronics and Applications (ICIEA), 2016, pp.1843-1846.

Reference 15: R. O’Hayre et al., Development of portable fuel cell arrays with printed-circuit technology, J. of Power Sources, Vol. 124, 2003, pp.459-472

Reference 16: A. Schmitz et al., Planar self-breathing fuel cells, J. of Power Sources, Vol. 118, 2003, pp.162-171

Reference 17: A. Schmitz, S. Wagner, R. Hahn, H. Uzun, C. Hebling, Stability of planar PEMFC in printed circuit board technology, J. of power Sources, Vol127, 2004, pp. 197-205.

Reference 18: S.H. Kim et al., Air-breathing miniature planar stack using the flexible printed circuit board as a current collector, International J. of Hydrogen Energy, Vol. 34, 2009, pp.459-466.

Reference 19: Y.-D. Kuan and C.-H. Chang, Experimental investigation on the process-induced damage of a DMFC assembled by the printed circuit board technique, J. of Fuel Cell Science and Technology, Vol. 6, 2009 , pp011016-1-9.

Reference 20: J.-Y. Chang et al., Characterization of a liquid feed direct methanol fuel cell with Sierpinski carpets fractal current collectors, J. of Power Sources, Vol. 184, pp. 180-190, 2008.

Reference 21: Y.-D. Kuan et al., Characterization of a direct methanol fuel cell using Hilbert curve fractal current collectors, J. of Power Sources, Vol. 187, Issue 1, 2009, pp.112-122.

Reference 22: Y.-D. Kuan et al., Experimental investigation of the effect of free openings of current collectors on a direct methanol fuel cell, J. of Power Sources, Vol.196, Issue 2, 2011, pp.717- 728.

Reference 23: Y.-D. Kuan et al., A novel flow design on the planar printed-circuit-board DMFC modules, Proceedings of FuelCell2008 Sixth International Fuel Cell Science, Engineering and Technology Conference, June 16-18, 2008, Denver , Colorado, USA.

Reference 24: W. Yuan et al., Lightweight current collector based on printed-circuit-board technology and its structural effects on the passive air-breathing direct methanol fuel cell, Renewable Energy, Vol. 81, 2015, pp.664-670 .

An object of the present invention is to provide a light-weight proton exchange membrane fuel cell battery structure and a method for manufacturing a fuel cell current collector plate, so as to improve the corrosion resistance of the current collector plate, thereby maintaining the stability of the fuel cell's long-term operation. .

In order to achieve the above object, one aspect of the present invention is to provide a battery structure of a lightweight proton exchange membrane fuel cell, including: an anode flow channel plate having a flow channel region formed by a meandering groove on an inner side thereof, and one end of the groove is formed A gas inlet and a gas outlet at the other end; an anode current collector plate with a plurality of arrays arranged in a matrix A first through hole, the anode current collector plate includes a first resin substrate, a first metal layer formed on the first resin substrate, and a first graphite film formed on the first metal layer; A proton exchange membrane; and a cathode current collector plate having a plurality of second through holes arranged in a matrix, the cathode current collector plate includes a second resin substrate, a second metal layer formed on the second resin substrate, And a second graphite film formed on the second metal layer, the first through hole of the anode current collector plate corresponds to the second through hole of the cathode current collector plate.

Another aspect of the present invention provides a method for manufacturing a current collector plate for a fuel cell, including: coating a first photoresist on a resin substrate; performing exposure and development, and patterning the first photoresist to define a current collector and Circuit pattern; plating a copper thin film layer by thermal evaporation method; performing a lift-off process to remove the remaining first photoresist to form a copper thin film pattern layer corresponding to the current collecting and circuit pattern; coating a first Two photoresists; performing exposure and development, patterning the second photoresist according to the current collecting and circuit pattern; forming a graphite film layer; and performing a lift-off process to remove the remaining second photoresist to the copper film A graphite thin film pattern layer corresponding to the current collecting and circuit pattern is formed on the pattern layer.

In one embodiment, the step of forming the graphite thin film layer includes: using a graphite target as a material, and forming the graphite thin film layer by a radio frequency magnetron sputtering method.

In an embodiment, the step of forming the graphite thin film layer includes: using a graphene ink as a material to form the graphite thin film layer by a screen printing method.

In an embodiment, the step of forming the graphite thin film layer includes: using the graphene dispersion liquid as a material to form the graphite thin film layer by a spin coating method.

In an embodiment, the step of patterning the first photoresist includes a pair of the first photoresist to perform a high-temperature setting step; the step of patterning the second photoresist includes a pair of the second photoresist Perform high temperature setting steps.

In one embodiment, the first photoresist and the second photoresist are positive photoresists.

In one embodiment, the fuel cell is a Proton Exchange Membrane Fuel Cell (PEMFC).

In one embodiment, the fuel cell is a direct methanol fuel cell (DMFC).

Another aspect of the present invention provides a battery structure of a lightweight proton exchange membrane fuel cell, including: an anode flow channel plate having a flow channel region formed by a meandering groove on an inner side thereof, and one end of the groove forming a gas inlet, A gas outlet is formed at the other end; an anode current collector plate having a plurality of first through holes arranged in a matrix. The anode current collector plate includes a first resin substrate and a first metal formed on the first resin substrate. Layer, and a first graphite thin film formed on the first metal layer; a proton exchange membrane; a cathode current collector plate having a plurality of second through holes arranged in a matrix, the cathode current collector plate includes a second A resin substrate, a second metal layer formed on the second resin substrate, and a second graphite film formed on the second metal layer, a first through hole of the anode current collector plate and the cathode current collector plate Corresponding to the second through hole; and a cathode penetrating plate having a plurality of penetrating holes penetrating both sides of the cathode penetrating plate; wherein hydrogen is sequentially passed from the gas inlet of the anode flow channel plate and in the flow channel area. Groove Through the first through hole of the anode current collector plate, the diffusion of the proton exchange membrane side; and wherein the oxygen in the air sequentially through the through holes of the cathode and the transparent plate The second through hole of the cathode current collector plate diffuses to the other side of the proton exchange membrane.

In the present invention, a graphite thin film is applied to a current collector plate of a proton exchange membrane fuel cell to improve the corrosion resistance of the current collector plate, thereby maintaining the stability of the fuel cell's long-term operation. In an embodiment, in the process of manufacturing the current collector plate, a FR4 / Epoxy composite material is used as a base material, and a current collector layer and an anti-corrosion layer are formed on the surface. The current collector layer is coated with a copper film by a thermal evaporation method, and a graphite film is used as an anti-corrosion layer to improve the corrosion resistance. Other embodiments of the present invention provide three different methods, such as radio frequency magnetron sputtering, screen printing, and spin coating, to produce a graphite film anticorrosive layer for a current collector plate.

11‧‧‧Anode runner plate

12‧‧‧Anode current collector plate

13‧‧‧ proton exchange membrane

14‧‧‧ cathode current collector

15‧‧‧cathode transparent plate

16‧‧‧ Silicone Gasket

60‧‧‧resin substrate

62‧‧‧first photoresist

64‧‧‧Cu film layer

65‧‧‧ Copper film pattern layer

66‧‧‧Second photoresist

68‧‧‧graphite film layer

69‧‧‧graphite film pattern layer

110‧‧‧lock hole

111‧‧‧ trench

112‧‧‧Gas inlet

113‧‧‧Gas outlet

121‧‧‧first through hole

141‧‧‧second through hole

151‧‧‧through hole

S10 ~ S17‧‧‧step

FIG. 1 is a schematic diagram showing a battery structure of a lightweight proton exchange membrane used in the present invention.

FIG. 2 is a schematic diagram showing the structure of the anode flow channel plate in FIG. 1.

FIG. 3 shows an explosion diagram of a PEMFC with double-sided and double-cell according to the present invention.

Fig. 4 shows the combined schematic diagram of the PEMFC of Fig. 3.

FIG. 5 shows a schematic diagram of a PEMFC with a double-sided and dual-cell manufacturing method according to the present invention.

FIG. 6 shows a flowchart of a method for manufacturing a current collector plate for a fuel cell according to the present invention.

Figures 7 and 8 show the principle of operation of RF magnetron sputtering.

Figure 9 shows a schematic diagram of transferring graphene ink to a substrate by screen printing technology.

Figure 10 shows a schematic design of a spin coating jig.

In order to make the objectives, technical solutions, and effects of the present invention more clear and clear, the present invention is further described in detail below with reference to the drawings and examples.

The article "a" or "an" as used in the specification of the invention and the scope of the appended patents can be generally interpreted as meaning "one or more" unless specified otherwise or clear from context.

FIG. 1 shows a schematic diagram of a battery structure of a lightweight proton exchange membrane used in the present invention, and FIG. 2 shows a schematic diagram of a structure of an anode flow channel plate 11 in FIG. 1. Referring to FIG. 1 and FIG. 2, the battery structure of the lightweight proton exchange membrane in the present invention includes: an anode flow channel plate 11 having a flow channel region formed by a meandering groove 111 on the inner side thereof, A gas inlet 112 is formed at one end and a gas outlet 113 is formed at the other end; an anode current collector plate 12 having a plurality of first through holes 121 arranged in a matrix. The anode current collector plate 12 includes a first resin substrate and is formed in A first metal layer on the first resin substrate, and a first graphite film formed on the first metal layer (see FIG. 6, a resin substrate corresponding element 60, a metal layer corresponding element 65, and a graphite thin film corresponding element 69); a proton exchange membrane 13; a cathode current collector plate 14 having a plurality of second through holes 141 arranged in a matrix, the cathode current collector plate 14 includes a second resin substrate formed on the second resin substrate A second metal layer and a second graphite film formed on the second metal layer (see FIG. 6, a resin substrate corresponding element 60, a metal layer corresponding element 65, and a graphite film corresponding element 69), the anode set First through hole of the electric board 12 121 corresponds to the second through hole 141 of the cathode current collecting plate 14; The cathode permeation plate 15 has a plurality of through holes 151, penetrating both sides of the cathode permeation plate 15; hydrogen gas sequentially passes from the gas inlet 112 of the anode flow channel plate 11 and the groove 111 in the flow channel area, and passes through The first through hole 121 of the anode current collector plate 12 diffuses to one side of the proton exchange membrane 13; oxygen in the air sequentially passes through the through holes 151 of the cathode through plate 15 and the first through hole 151 of the cathode current collector plate 14. The two through holes 141 diffuse to the other side of the proton exchange membrane 13.

The power generated by the fuel cell needs to output power to the outside through the medium of the collector plate or bipolar plate (ie, the anode collector plate 12 and the cathode collector plate 14). The bipolar of the proton exchange membrane fuel cell of the present invention After the plate is plated with a metal layer (such as a copper layer) on the resin substrate, and then coated with a graphite anti-corrosion layer (graphite film or graphite thin), graphite (Graphite) has good electrical and thermal conductivity, and also has good resistance Corrosiveness, which improves the corrosion resistance of the micro PEMFC collector plate, and can still maintain the stability of performance under long-term operation, which improves the performance of the fuel cell.

As shown in FIG. 1, the battery structure of the lightweight proton exchange membrane in the present invention further includes a plurality of silicon gaskets 16 disposed between the anode flow channel plate 11 and the anode current collector plate 12, and the anode current collector plate 12 and Between the proton exchange membrane 13 and between the cathode current collector plate 14 and the proton exchange membrane 13. These silicon gaskets 16, anode flow channel plate 11, anode current collector plate 12, cathode current collector plate 14, and cathode transparent plate 15 are provided with locking holes 110 at the periphery, which are mainly used to lock fuel cells when The locking torque is distributed evenly to prevent fuel leakage caused by uneven force application.

The flow path area of the anode flow path plate 11 uses a meandering flow path to increase the reaction area. The fuel inlet and outlet holes (that is, the gas inlet 112 and the gas outlet 113) are provided in the flow. At the opposite corner of the channel, the aperture is designed according to the diameter of the duct (ie, the groove 111), and the duct is mainly used for fuel input and output.

In the above structure, a cathode permeation plate 15 is used on the outside of the cathode current collecting plate 14, which can directly contact the outside air and directly use oxygen in the air as a fuel. This structure is an open structure. The present invention can also replace the cathode permeation plate 15 with a cathode flow channel plate, which adopts the same structure as the anode flow channel plate 11, except that oxygen is input as fuel, and this structure is a closed structure. Compared with the closed architecture, the advantages of the open architecture are that it does not need to be equipped with oxygen fuel, which further reduces the product volume and achieves the purpose of miniaturization.

After the lightweight components (namely, the anode flow channel plate 11, the anode current collecting plate 12, the proton exchange membrane 13, the cathode current collecting plate 14, the cathode transparent plate 15, and the silicone gasket 16) are completed, the components are sequentially assembled After being locked together, the lightweight PEMFC single battery is completed. The above-mentioned components can also be assembled by thermocompression bonding to complete the production of PEMFC cells.

Based on the production of the single-cell (cell) PEMFC described above, the present invention can also be applied to the production of double-sided and dual-cell PEMFCs. As shown in FIG. 3, the opposite two sides each have two battery modules, which can sequentially increase the battery capacity. The PEMFC with double-sided and double-cell can be assembled by locking, as shown in Figure 4; it can also be assembled by thermocompression, as shown in Figure 5.

The present invention also provides a method for manufacturing a current collector plate for a fuel cell. As shown in FIG. 6, it shows a flowchart of a method for manufacturing a current collector plate for a fuel cell according to the present invention. The current collector plate is the foregoing anode collector. The electric plate 12 and the cathode current collecting plate 14 The manufacturing method includes the following steps:

Step S10: A first photoresist 62 is coated on a resin substrate 60. The resin substrate 60 may be a FR4 / Epoxy composite material, and the first photoresist 62 may be a positive photoresist.

Step S11: performing exposure and development, and patterning the first photoresist 62 to define a current collecting and circuit pattern.

Step S12: plating a copper thin film layer 64 by a thermal evaporation method.

Step S13: A lift-off process is performed to remove the remaining first photoresist to form a copper thin film pattern layer 65 corresponding to the current collecting and circuit patterns.

Step S14: apply a second photoresist 66. The second photoresist 66 may be a positive photoresist.

Step S15: performing exposure and development, and patterning the second photoresist 66 according to the current collecting and circuit patterns.

Step S16: forming a graphite thin film layer 68.

Step S17: A lift-off process is performed to remove the remaining second photoresist to form a graphite thin film pattern layer 69 corresponding to the current collecting and circuit patterns on the copper thin film pattern layer 65.

The base material of PEMFC can be FR4 / Epoxy composite material used in the PCB manufacturing process, and the conductive layer is coated with a copper thin film as the conductive layer using Thermal Evaporation. The main reason for using thermal evaporation instead of sputtering deposition is that thermal evaporation can control a faster deposition rate, can produce thicker metal films, and thus has higher conductivity. Collector plate, sputter deposition method although better deposition Uniformity and step coverage, but it is more difficult to plate a thick film, and it takes a long time. Since the PEMFC composite collector substrate with copper film produced by this process will be coated with a graphite film anti-corrosion layer and conductive circuits connected in series in the subsequent steps, it will be coated on the FR4 / Epoxy substrate before After the previous steps of positive photoresist, exposure, development, and high-temperature sizing, a thin layer of copper is then thermally evaporated, and then the metal is lifted off to produce the current collecting and circuit patterns required for the metal current collecting layer. Subsequently, secondary coating of positive photoresist, exposure and development, and high-temperature setting will be performed. In this way, the current collector substrate has been prepared for the preparation of a corrosion-resistant layer of a graphite film. The thickness of the FR4 Glass / Epoxy substrate is about 0.5mm, and the thickness of the copper current collector layer is about 30 ~ 50kÅ. After the current collector plate has completed the graphite thin film anti-corrosion layer, the lift-off process will be performed to complete the current collecting and circuit pattern of the graphite anti-corrosion layer. This completes the copper thin film current collector layer and the graphite thin film anti-corrosion layer. The production of collector plates.

The present invention also proposes three methods to make a graphite film (corresponding to steps S16 and S17 above). The first method is radio frequency magnetron sputtering and the material is a graphite target. The second method is screen printing and the material is graphene ink. The third method is a spin coating method, and the material is a graphene dispersion.

First, radio frequency magnetron sputtering to produce anticorrosive layer of graphite film

The operation principle and mechanism of RF magnetron sputtering is shown in Figures 7 and 8. First, the graphite target is placed in the vacuum cavity of the sputtering machine, the cavity is evacuated, and electricity is generated between the two electrodes to generate electrons. These When the accelerated electron collides with an inert gas in the cavity (such as argon atoms), a free electron and a positively charged argon ion plasma are generated. These argon ions will be attracted by the cathode graphite target and impact the graphite target, so that The electrons or molecules leave the surface of the target and travel in the vacuum cavity in the form of vapor, and then deposit on the surface of the substrate to form a graphite film.

Second, screen printing production of graphite film anti-corrosion layer

Graphene conductive ink is a very common application. It is usually composed of graphene, base resin, auxiliary agent and solvent, which make it have ink products with special functions such as conductivity. It has excellent conductivity, light weight, Good processing conditions, easy control and low cost. FIG. 9 is a schematic diagram of transferring graphene ink to a substrate by screen printing technology. First, the composite current collector substrate with a copper current collector layer must be laid flat, the graphene conductive ink is poured into the screen, and then the graphene conductive ink is scraped with a scraper to transfer it to the current collector substrate. The vacuum oven in which the substrate is made is evacuated and heated to evaporate the solvent in the graphene ink to improve its conductivity, thereby completing the production of the anticorrosive layer of the graphite film in the current collector plate. In the heating process of the vacuum oven, in order to prevent the components of the graphene ink from forming holes due to boiling and evaporation, thereby reducing the conductivity, step heating can be adopted, that is, the temperature is gradually increased in stages.

Third, spin coating to produce anticorrosive layer of graphite film

Graphene also often exists as a graphene suspension (Graphene Suspension), which is a uniformly dispersed graphene composite fluid. The graphene suspension used in the present invention is mainly dispersed in graphene flakes in an ethanol solvent, and then In a spin coating method, a graphene suspension is uniformly coated on a current collector substrate having a copper conductive layer. After the completion, the current collecting substrate was placed in a vacuum oven, and the temperature was gradually increased in a stepwise heating manner to evaporate the ethanol solvent, leaving a graphene film. Figure 10 is a schematic design of a spin coating jig. During the spin coating process, one can make a The round fixture, the current collector substrate is placed in this fixture, so that the graphene suspension can be more evenly and smoothly distributed on the current collector substrate. In addition, the outermost circle of the circle can be designed as a groove to allow the The graphene suspension is recovered and reused, saving material.

In the present invention, a graphite thin film is applied to a current collector plate of a proton exchange membrane fuel cell to improve the corrosion resistance of the current collector plate, thereby maintaining the stability of the fuel cell's long-term operation. In an embodiment, in the process of manufacturing the current collector plate, a FR4 / Epoxy composite material is used as a base material, and a current collector layer and an anti-corrosion layer are formed on the surface. The current collector layer is coated with a copper film by a thermal evaporation method, and a graphite film is used as an anti-corrosion layer to improve the corrosion resistance. Other embodiments of the present invention provide three different methods, such as radio frequency magnetron sputtering, screen printing, and spin coating, to produce a graphite film anticorrosive layer for a current collector plate.

The present invention has been disclosed as above with preferred embodiments, but it is not intended to limit the present invention. Those with ordinary knowledge in the technical field to which the present invention pertains may make various changes without departing from the spirit and scope of the present invention. And retouching, so the scope of protection of the present invention shall be determined by the scope of the attached patent application.

Claims (8)

A manufacturing method of a fuel cell current collector plate includes: coating a first photoresist on a resin substrate; performing exposure and development, and patterning the first photoresist to define a current collecting and circuit pattern; A copper thin film layer is plated by plating; a lift-off process is performed to remove the remaining first photoresist to form a copper thin film pattern layer corresponding to the current collecting and circuit pattern; a second photoresist is applied; and exposure is performed Developing, patterning the second photoresist according to the current collecting and circuit pattern; forming a graphite thin film layer; and performing a lift-off process to remove the remaining second photoresist to form the copper thin film pattern layer and the Collects the graphite thin film pattern layer corresponding to the circuit pattern. The method according to item 1 of the scope of the patent application, wherein the step of forming the graphite thin film layer includes: using a graphite target as a material to form the graphite thin film layer by a radio frequency magnetron sputtering method. The method according to item 1 of the scope of the patent application, wherein the step of forming the graphite thin film layer includes: using a graphene ink as a material to form the graphite thin film layer by a screen printing method. The method according to item 1 of the scope of the patent application, wherein the step of forming the graphite thin film layer comprises: using the graphene dispersion liquid as a material to form the graphite thin film layer by a spin coating method. The method according to item 1 of the patent application scope, wherein the step of patterning the first photoresist includes a step of performing a high-temperature setting of the pair of the first photoresist; and after the step of patterning the second photoresist, the method includes A step of setting the second photoresist at a high temperature. The method according to item 1 of the patent application range, wherein the first photoresist and the second photoresist are positive photoresists. The method according to item 1 of the application, wherein the fuel cell is a Proton Exchange Membrane Fuel Cell (PEMFC). The method according to item 1 of the scope of patent application, wherein the fuel cell is a direct methanol fuel cell (DMFC).