WO2021077644A1 - 燃料电池双极板及其加工方法 - Google Patents

燃料电池双极板及其加工方法 Download PDF

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Publication number
WO2021077644A1
WO2021077644A1 PCT/CN2020/073198 CN2020073198W WO2021077644A1 WO 2021077644 A1 WO2021077644 A1 WO 2021077644A1 CN 2020073198 W CN2020073198 W CN 2020073198W WO 2021077644 A1 WO2021077644 A1 WO 2021077644A1
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WIPO (PCT)
Prior art keywords
flow channel
bipolar plate
fuel cell
cross
depth
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PCT/CN2020/073198
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English (en)
French (fr)
Inventor
胡尊严
李建秋
徐梁飞
刘慧泽
徐领
欧阳明高
Original Assignee
清华大学
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Publication date
Priority claimed from CN201911006524.0A external-priority patent/CN110783596B/zh
Priority claimed from CN201911006521.7A external-priority patent/CN110854406A/zh
Priority claimed from CN201911005875.XA external-priority patent/CN110739468B/zh
Application filed by 清华大学 filed Critical 清华大学
Publication of WO2021077644A1 publication Critical patent/WO2021077644A1/zh
Priority to US17/341,262 priority Critical patent/US20210296660A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/02—Details
    • H01M8/0202—Collectors; Separators, e.g. bipolar separators; Interconnectors
    • H01M8/0258—Collectors; Separators, e.g. bipolar separators; Interconnectors characterised by the configuration of channels, e.g. by the flow field of the reactant or coolant
    • H01M8/0263—Collectors; Separators, e.g. bipolar separators; Interconnectors characterised by the configuration of channels, e.g. by the flow field of the reactant or coolant having meandering or serpentine paths
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/02—Details
    • H01M8/0202—Collectors; Separators, e.g. bipolar separators; Interconnectors
    • H01M8/0204—Non-porous and characterised by the material
    • H01M8/0213—Gas-impermeable carbon-containing materials
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/02—Details
    • H01M8/0202—Collectors; Separators, e.g. bipolar separators; Interconnectors
    • H01M8/0204—Non-porous and characterised by the material
    • H01M8/0223—Composites
    • H01M8/0228—Composites in the form of layered or coated products
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/02—Details
    • H01M8/0202—Collectors; Separators, e.g. bipolar separators; Interconnectors
    • H01M8/0258—Collectors; Separators, e.g. bipolar separators; Interconnectors characterised by the configuration of channels, e.g. by the flow field of the reactant or coolant
    • H01M8/026—Collectors; Separators, e.g. bipolar separators; Interconnectors characterised by the configuration of channels, e.g. by the flow field of the reactant or coolant characterised by grooves, e.g. their pitch or depth
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/02—Details
    • H01M8/0202—Collectors; Separators, e.g. bipolar separators; Interconnectors
    • H01M8/0258—Collectors; Separators, e.g. bipolar separators; Interconnectors characterised by the configuration of channels, e.g. by the flow field of the reactant or coolant
    • H01M8/0265—Collectors; Separators, e.g. bipolar separators; Interconnectors characterised by the configuration of channels, e.g. by the flow field of the reactant or coolant the reactant or coolant channels having varying cross sections
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/30—Hydrogen technology
    • Y02E60/50—Fuel cells
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

Definitions

  • the present disclosure relates to the technical field of fuel cells, in particular to a fuel cell bipolar plate and a processing method thereof.
  • the bipolar plate is the core component of the fuel cell, and the design of the bipolar plate is the core factor that determines the performance of the fuel cell.
  • the surface of the bipolar plate is provided with structures such as a cathode runner, an anode runner, and a cooling runner.
  • the cathode and anode flow channel structure undertakes the functions of reacting gas distribution, gas cooling, and drainage in the fuel cell.
  • the bipolar plate runner groove is usually processed by machine tool processing and compression molding. Reducing the width of the spine of the flow channel can increase the diffusion efficiency of the reactive gas to the area under the spine. Therefore, increasing the density of the flow channel arrangement can improve the performance of the fuel cell. Due to the brittleness of graphite material and processing molds, it is difficult to process dense runners with narrow ridges by machine tool processing and compression molding methods. As a result, the ridge width of the bipolar plate runners of existing mainstream products is at the level of 1 mm. The inventor In the known technology, continuing to reduce the width of the runner spine will greatly increase the processing cost and processing time. Further breakthroughs in fuel cell performance need to reduce the width of the back of the flow channel on the bipolar plate to a level of 0.2 mm to 0.3 mm.
  • the flow channel on the bipolar plate is responsible for the multiple tasks of uniformly distributing gas reactants and purging and discharging the generated water.
  • the water produced by the reaction will move toward the outlet of the flow channel. From the inlet of the flow channel to the outlet of the flow channel, the liquid water in the flow channel and the gas diffusion layer gradually increases. The liquid water hinders the transfer of the reaction gas. Improving the mass transfer and drainage capacity of the gas in the flow channel is the key to improving the performance of the fuel cell.
  • a method for processing a fuel cell bipolar plate including:
  • a laser is used to process a flow channel on the surface of the graphite bipolar plate blank to obtain a shaped graphite bipolar plate.
  • the fuel cell bipolar plate processing method provided in the present disclosure includes obtaining a graphite bipolar plate blank.
  • the flow channel is processed on the graphite bipolar plate blank by using a laser to obtain a formed graphite bipolar plate.
  • the width of the runner ridge processed by the tool is in the millimeter level, and the width of the molded ridge of the molded mold is also the millimeter level.
  • the processing method uses a laser to process the flow channel.
  • the laser spot has a diameter of micrometers and does not generate mechanical stress. The laser can process a narrower back width and a tighter arrangement of the flow channels.
  • the processing method further includes performing surface cleaning treatment and surface hydrophobic treatment on the shaped graphite bipolar plate, and the flow channel after the surface hydrophobic treatment is not easy to accumulate water. Furthermore, the conveying capacity of the bipolar plate runner formed by the processing method is enhanced, and the processing method improves the performance of the bipolar plate.
  • Fig. 1 is an electrical schematic diagram of the fuel cell bipolar plate processing method provided in an embodiment of the present disclosure
  • FIG. 2 is a structural diagram of the target flow channel provided in an embodiment of the present disclosure
  • Fig. 3 is a diagram of the overall processing path provided in an embodiment of the present disclosure.
  • Fig. 4 is a partial structural diagram of the A-A provided in an embodiment of the present disclosure.
  • Fig. 5 is a schematic structural diagram of the laser engraving machine provided in an embodiment of the present disclosure.
  • FIG. 6 is a schematic diagram of the position of the refractor provided in an embodiment of the present disclosure.
  • FIG. 7 is an image diagram of the bottom of the focused flow channel of the formed graphite bipolar plate provided in an embodiment of the present disclosure
  • Fig. 8 is a structural diagram of the fuel cell bipolar plate provided in an embodiment of the disclosure.
  • Fig. 9 is a top structural view of the fuel cell bipolar plate provided in an embodiment of the present disclosure.
  • FIG 10 is an A-A cross-sectional view of the fuel cell bipolar plate provided in an embodiment of the disclosure.
  • FIG. 11 is a top structural view of the ridge provided with a chute provided in an embodiment of the present disclosure.
  • Fig. 12 is a top structural view of an opening on the bottom surface of the groove provided in an embodiment of the present disclosure
  • Figure 13 is a B-B cross-sectional view of an opening on the bottom surface of the groove provided in an embodiment of the present disclosure
  • FIG. 14 is a top structural view of an opening on the bottom surface of the chute provided in an embodiment of the present disclosure.
  • Figure 15 is a top structural view of the ridge opening provided in an embodiment of the present disclosure.
  • FIG. 16 is a top structural view of the ridge opening provided in another embodiment of the present disclosure.
  • Figure 17 is a structural diagram of the fuel cell bipolar plate provided in an embodiment of the present disclosure.
  • FIG. 18 is a structural diagram of a flow channel width linearly continuously changing provided in an embodiment of the present disclosure.
  • 19 is a side view of the structure of the bipolar plate of the fuel cell provided in an embodiment of the present disclosure.
  • FIG. 20 is a cross-sectional view of the A-A cross-sectional view of the runner width linearly continuously changing provided in an embodiment of the present disclosure
  • FIG. 21 shows that the cross-sectional shape of the flow channel provided in an embodiment of the present disclosure is a hexagon
  • FIG. 23 is a structural diagram that provides a non-linear and continuous change of the width of the flow channel in another embodiment of the present disclosure.
  • FIG. 24 is a structural diagram of providing a stepped change in the width of a runner in another embodiment of the present disclosure.
  • FIG. 25 is a structural diagram that provides a linear and continuous change of the depth of the runner in another embodiment of the present disclosure.
  • Fig. 26 is a cross-sectional view of the A-A section of the runner depth linearly continuously changing provided in another embodiment of the present disclosure
  • FIG. 27 is a structural diagram that provides a non-linear and continuous change of the depth of the flow channel in another embodiment of the present disclosure.
  • FIG. 28 is a structural diagram that provides a stepped change in the depth of the runner in another embodiment of the present disclosure.
  • FIG. 29 is a structural diagram of the width and width of the runner provided in an embodiment of the present disclosure.
  • FIG. 30 is a structural diagram of a flow channel provided in another embodiment of the present disclosure.
  • Figure 31 is a flow channel structure diagram provided in another embodiment of the present disclosure.
  • FIG. 32 is a structural diagram of a bipolar plate provided in another embodiment of the present disclosure.
  • FIG. 33 is a structural diagram of a continuous change in the depth of the flow channel and a constant bottom thickness provided in an embodiment of the present disclosure
  • FIG. 34 is a structural diagram of a bipolar plate provided in another embodiment of the present disclosure.
  • 35 is a structural diagram of a bipolar plate provided in another embodiment of the present disclosure.
  • Fig. 36 is a schematic diagram of laser processing provided in another embodiment of the present disclosure.
  • Fuel cell bipolar plate 10 substrate 100, diffusion layer 101, first flow channel 102, second flow channel 103, first surface 110, ridge 104, groove 105, second surface 140, flow channel 112, inlet 121, outlet 122, ridge 104, conveying direction A, first direction a first Two directions b, angle ⁇ , spacing L, width W, depth H, thickness T, third runner unit 200, third runner 210, first ridge 220, fourth runner unit 300, fourth runner 310, second ridge 320, first substrate 400, second Substrate 500 Third surface 510 Fourth surface 520 First reactant intake manifold 610 First reactant exhaust manifold 620 Second reactant exhaust manifold 630 Second reactant intake manifold 640 Cooling water intake manifold Tube 650 First hole 70 First hole 710 Second hole 720 Second hole 80 First hole 810 Second hole 820 Laser generator 120 Moving structure 130 Platform 131 Refractor 150 Target flow channel structure Figure 30 Target flow channel 300 Flow channel Spacing D First target runner 310 Second target runner
  • connection and “connection” in the present disclosure, unless otherwise specified, include direct and indirect connection (connection).
  • connection in the description of the present disclosure, it should be understood that the terms “upper”, “lower”, “front”, “rear”, “left”, “right”, “vertical”, “horizontal”, “top”, The orientation or positional relationship indicated by “bottom”, “inner”, “outer”, “clockwise”, “counterclockwise”, etc.
  • the first feature “on” or “under” the second feature may be in direct contact with the first and second features, or the first and second features may be indirectly through an intermediary. contact.
  • the "above”, “above” and “above” of the first feature on the second feature may mean that the first feature is directly above or diagonally above the second feature, or it simply means that the level of the first feature is higher than the second feature.
  • the “below”, “below” and “below” of the second feature of the first feature may be that the first feature is directly below or obliquely below the second feature, or it simply means that the level of the first feature is smaller than the second feature.
  • the bipolar plate is the core component of the fuel cell, and the design of the bipolar plate is the core factor that determines the performance of the fuel cell.
  • the bipolar plate has structures such as a cathode flow channel, an anode flow channel, and a cooling flow channel.
  • the bipolar plate undertakes the functions of reacting gas distribution, cooling, and drainage in the fuel cell.
  • the graphite bipolar plate has strong corrosion resistance.
  • Graphite bipolar plates are usually used to design long-life fuel cell stacks. In order to improve the performance of the bipolar plate, technicians have continuously narrowed the width and density of the spine. Existing bipolar plate groove depth and groove width are usually at the level of 1 mm, and some processing techniques can reach 0.4 mm. However, no matter whether it is processed by CNC machine tools or compression molding, further reducing the width of the spine and increasing the density of the runners have the problems of high cost and low efficiency.
  • a fuel cell bipolar plate processing method including:
  • S300 use a laser to process a flow channel on the surface of the graphite bipolar plate blank to obtain a formed graphite bipolar plate.
  • S400 Perform surface cleaning treatment and surface hydrophobic treatment on the shaped graphite bipolar plate.
  • the fuel cell bipolar plate processing method uses a laser to process the flow channel on the graphite bipolar plate blank according to the target flow channel structure Fig. 1 to obtain a formed graphite bipolar plate.
  • the width of the runner ridge processed by the tool is in the millimeter level, and the width of the molded ridge of the molded mold is also in the millimeter level.
  • the processing method uses a laser to process the flow channel.
  • the laser spot has a diameter of micrometers and does not generate mechanical stress. The laser can process a narrower back width and a tighter arrangement of the flow channels.
  • the processing method further includes performing surface cleaning treatment and surface hydrophobic treatment on the shaped graphite bipolar plate, and the flow channel after the surface hydrophobic treatment is not easy to accumulate water. Furthermore, the conveying capacity of the bipolar plate runner formed by the processing method is enhanced, and the processing method improves the performance of the bipolar plate.
  • the step S100 includes processing to form an original blank of a rigid bipolar plate.
  • a mechanical processing machine tool is used to open inlets and outlets and common flow passage pores on the surface of the original blank of the hard bipolar plate to form the blank of the graphite bipolar plate.
  • the step S100 includes using graphite powder to mold the graphite bipolar plate blank, and the surface of the graphite bipolar plate blank has been provided with inlets and outlets, common flow channel pores and main flow channels.
  • the main runner is formed by a compression molding method.
  • the main flow channel on the surface of the graphite bipolar plate blank is finely processed by the S200 to improve the gas diffusion capacity of the main flow channel.
  • the principle of laser engraving is to use a high-energy laser beam to melt the graphite and resin materials scanned by the burning laser to form a runner groove.
  • the S200 includes:
  • S210 according to the target flow channel structure FIG. 1, obtain the flow channel width, the flow channel depth, the flow channel extension shape and the flow channel spacing D of the target flow channel 300.
  • S220 Select the laser spot diameter and light travel distance according to the width of the flow channel.
  • S230 Select the scanning frequency, the light running speed and the number of processing scans according to the depth of the flow channel.
  • S240 Obtain the overall processing path diagram 40 according to the extending shape of the flow channel, the distance D of the flow channel, the diameter of the light spot, and the light running distance.
  • the flow channel spacing D refers to the distance between adjacent side walls between two adjacent flow channels.
  • the light running distance refers to the distance between the midpoints of two adjacent scanning light spots, wherein the two adjacent scanning light spots are used for processing two adjacent scanning lines.
  • the S240 includes:
  • the target flow channel structure diagram 1 includes a plurality of target flow channels 300
  • the overall processing path diagram 40 includes a plurality of scan line groups 400
  • each scan line group 400 includes multiple scan lines
  • the shape of the scan line corresponding to the target flow channel 300 is obtained according to the extension shape of the flow channel.
  • S242 Calculate the number of light passes of each target flow channel 300 according to the spot diameter, the light distance and the width of the flow channel, obtain the number of scan lines according to the number of light passes, and obtain the number of scan lines according to the light distance
  • the scan line spacing h2 of the corresponding two adjacent scan lines is obtained, and the two adjacent scan lines are located in one scan line group 400.
  • S244 Obtain the overall processing path diagram 40 according to the shape of the scan line, the number of the scan line, the scan line spacing h2 and the scan group spacing h1.
  • a plurality of scan lines of one scan line group 400 are arranged in parallel.
  • the shape of the scan line includes a straight line, a broken line, and an arc line.
  • the number of light passes formula can be used to obtain the number of light passes.
  • the formula for the number of run-outs is:
  • n (X-Y)/(p+1)
  • n the number of light travels
  • X the width of the flow channel
  • Y the diameter of the light spot
  • p the light travel distance
  • the selection of the light travel distance is based on the laser processing characteristics of the graphite bipolar plate blank.
  • the proper light-traveling distance can not only ensure the processing speed, but also ensure the surface roughness.
  • a preliminary experiment of light-going distance is required before selecting the light-going distance.
  • the preparatory experiment of the optical distance includes multiple laser processing with different optical distances, and measuring the processing accuracy of the surface of the flow channel.
  • the light-travel spacing is equal to the scan line spacing.
  • the S300 is based on the spot diameter, the scanning frequency, the light traveling speed, the number of processing scans, and the overall processing path diagram 40, using a laser on the graphite bipolar plate blank
  • the flow channel is processed up to obtain the shaped graphite bipolar plate.
  • a laser engraving machine is used to process the graphite bipolar plate blank.
  • the laser engraving machine includes an overall control device, a laser generator 120, a platform 131 and a moving structure 130.
  • the laser generator 120 and the moving structure 130 are respectively electrically connected to the overall control device.
  • the overall control device is used to receive external commands, and control the laser generator 120 and the mobile structure 130 to work together according to the external commands.
  • the laser generator 120 is used to generate laser light.
  • the platform 131 is used to fix the graphite bipolar plate blank and provide a processing platform.
  • the moving structure 130 is fixedly connected to the probe 121 of the laser generator 120 and is used to drive the laser probe 121 to move according to the overall processing path diagram 40.
  • the moving structure 130 has a spatial three-dimensional movement function.
  • the step of processing the graphite bipolar plate blank by the laser engraving machine includes:
  • the overall control device controls the laser generator 120 and the moving structure 130 to work together to perform flow channel processing on the surface of the graphite bipolar plate blank.
  • the laser engraving machine further includes a refractor 150.
  • the refractor 150 is arranged on the laser path and used to change the direction of the laser.
  • a variety of the target runners can be processed by the laser engraving machine.
  • the target flow channel may be a space structure such as an oblique hole on the spine, a trapezoidal groove, and the like.
  • a ridge is formed between two adjacent target flow channels 300, and the above-mentioned method is also used for processing the structure of openings, grooves and their combination on the ridges.
  • the processing method before the step S230, the processing method further includes:
  • S221 Perform a pre-scan experiment to determine the scanning frequency, the light running speed, and the number of processing scans.
  • the S221 includes:
  • S14 Determine the number of processing scans according to the first depth, the second depth, M, N, and the depth of the flow channel.
  • a difference method is used to determine the number of processing scans to improve scan accuracy.
  • the selection of the light speed depends on the accuracy of the equipment and the design capability of the runner processing.
  • the variable light traveling speed method is adopted.
  • the first light speed is used.
  • the second light speed is used. The first light traveling speed is greater than the second light traveling speed.
  • a high-energy laser is used in the S200 to process the flow channel of the graphite bipolar plate blank.
  • the material of the graphite bipolar plate is changed to a vaporized plasma state to avoid the accumulation of processing residues and processing defects.
  • the depth of the flow channel for laser processing corresponds to the volume of graphite that can be melted and burnt per unit time of laser emission.
  • Runner processing is a balanced choice between processing speed and accuracy. The greater the energy, the faster the scan, the faster the processing speed, and the lower the accuracy.
  • the high-energy laser is a picosecond laser, a femtosecond laser, and a nanosecond laser.
  • the fuel cell bipolar plate processing method uses a small spot laser with a level of 10 micrometers to 200 micrometers. Since the energy distribution of the laser engraving spot obeys the Gaussian distribution, the closer to the center of the laser spot, the higher the energy of the laser. Using a small light spot can reduce the difference in energy distribution and improve processing accuracy.
  • a fiber laser is used to process the flow channel of the graphite bipolar plate blank.
  • the wavelength of the laser used for graphite processing should be larger in energy and shorter in wavelength.
  • the wavelength of CO2 laser is too long and the energy is small, so it is not suitable for graphite processing.
  • Fiber laser has short wavelength and high energy, which is suitable for graphite processing.
  • a laser with a shorter wavelength than the fiber laser can also be used for processing.
  • the step of obtaining the shape of the scan line corresponding to the target flow channel 300 according to the extended shape of the target flow channel 300 further includes:
  • S21 Determine whether the target flow channel 300 includes a corner structure.
  • the scan line corresponding to the corner structure is an arc chamfer structure 402.
  • the target flow channel 300 includes a right-angled flow channel structure, and the right-angled flow channel structure is designed as the arc-shaped chamfered structure 402 to avoid repeated processing of local positions and improve processing accuracy.
  • the plurality of target flow channels 300 includes a first target flow channel 310 and a second target flow channel 320
  • the plurality of scan line groups 400 includes a first scan line group 410 and a second scan line group 420.
  • the first scan line group 410 includes a plurality of first scan lines 411
  • the first scan line 411 corresponds to the first target flow channel 310
  • the second scan line group 420 includes a plurality of second scan lines.
  • the second scan line 421 corresponds to the second target flow channel 320.
  • S241 according to the extended shape of the target flow channel 300, all the corresponding to the target flow channel 300 are obtained.
  • the step of describing the shape of the scan line also includes:
  • S31 Determine whether the starting point B of the first target flow channel overlaps with the extension path of the second target flow channel 320.
  • Setting the machining allowance gap means setting a certain gap between the starting point b of the first scan line and the second scan line 421 to ensure that the center of the light spot does not repeatedly scan the gap position and improve the machining accuracy.
  • the length of the gap is in the same order of magnitude as the radius of the light spot.
  • the experiment uses an ordinary expanded graphite plate and an 80W picosecond laser, uses a fixed light travel speed of 1m/s, and scans 100 times with 50% energy in the preliminary experiment to obtain the results.
  • the depth of the flow channel is about 0.2mm.
  • Using 40% energy to scan 500 times, the depth of the flow channel is about 0.75 mm.
  • the differential method the depth of the flow channel is 0.3 mm, 50% energy is used, and each scan line is scanned 150 times.
  • the design goal is a flow channel 0.3 mm wide and 0.3 mm deep. Based on the results of preliminary experiments, the final design of the runner is as follows:
  • the spot diameter is 50um; the scanning pitch is 20um; the scanning frequency is 300kHz; the number of scanning is 150 times for each scanning line; the scanning speed is 1m/s; the scanning energy is 50% (maximum 80W).
  • FIG. 7 is an image diagram of the bottom 101 of the focused flow channel of the shaped graphite bipolar plate obtained by using the above-mentioned parameters.
  • the bottom of the formed runner 112 has good flatness.
  • a ridge 104 is formed between two adjacent flow channels 112.
  • a fuel cell bipolar plate including a substrate.
  • the surface of the substrate is provided with adjacent first flow channels and second flow channels.
  • a ridge is formed between the first flow channel and the second flow channel.
  • a groove is provided on the top surface of the ridge, and one or two of the first flow passage or the second flow passage are in communication with the groove.
  • the fuel cell bipolar plate provided by the embodiment of the present disclosure includes a substrate.
  • the surface of the substrate is provided with adjacent first flow channels and second flow channels.
  • a ridge is formed between the first flow channel and the second flow channel.
  • a groove is provided on the top surface of the ridge, and one or two of the first flow passage or the second flow passage are in communication with the groove. The water accumulated in the contact portion of the ridge and the cathode diffusion layer will penetrate into the groove, and then flow into the first flow channel or the second flow channel through the groove, and be carried away by the reaction gas.
  • the groove effectively avoids local water accumulation, thereby improving the drainage performance inside the fuel cell.
  • the fuel cell bipolar plate increases the local flow rate of the reactant gas, improves the mass transfer efficiency of the reactant gas through the diffusion layer, and further improves the performance of the fuel cell. Further, the groove reduces the contact area between the ridge of the bipolar plate and the gas diffusion layer, and increases the effective area of gas diffusion in the gas diffusion layer, thereby improving the performance of the fuel cell.
  • the fuel cell undergoes an electrochemical reaction during operation to generate water in the cathode catalyst layer.
  • the water produced by the reaction reaches the flow channel through the diffusion layer and is taken away by the reaction gas in the flow channel.
  • the reaction gas flows in the flow channel and the gas diffusion layer. Relative to the inside of the flow channel, the contact surface of the ridge and the cathode diffusion layer prevents the water in the diffusion layer from entering the flow channel, and the water stays in the contact part, hindering the mass transfer of the reaction gas from the flow channel to the catalyst layer, thereby affecting the operation of the fuel cell performance.
  • an embodiment of the present disclosure provides a fuel cell bipolar plate 10 including a substrate 100.
  • the surface of the substrate 100 is provided with a first flow channel 102 and a second flow channel 103 adjacent to each other.
  • a ridge 104 is formed between the first flow channel 102 and the second flow channel 103.
  • a groove 105 is provided on the top surface of the ridge 104, and one or two of the first flow channel 102 or the second flow channel 103 are in communication with the groove 105.
  • the fuel cell bipolar plate 10 provided by the embodiment of the present disclosure includes a substrate 100.
  • the groove 105 is provided on the top surface of the ridge 104, and one or two of the first flow channel 102 or the second flow channel 103 are in communication with the groove 105. Water will penetrate into the groove 105, then flow into the first flow channel 102 or the second flow channel 103 through the groove 105, and be carried away by the reaction gas.
  • the groove 105 effectively avoids local water accumulation, thereby improving the drainage performance inside the fuel cell.
  • the fuel cell bipolar plate 10 increases the local flow rate of the reactant gas, improves the mass transfer efficiency of the reactant gas through the diffusion layer, and further improves the performance of the fuel cell. Further, the groove 105 reduces the contact area between the ridge 104 and the gas diffusion layer 101 and increases the effective area of gas diffusion in the gas diffusion layer 101, thereby improving the performance of the fuel cell.
  • the cross-sectional shape of the groove 105 may be multi-deformed, circular or partially arc-shaped.
  • the groove 105 is in communication with the first flow passage 102 or the second flow passage 103, and the water near the groove 105 is introduced into the first flow passage 102 or the second flow passage 103, reducing The local accumulation of water increases the contact probability of gas, hydrogen ions and electrons, thereby improving the performance of the fuel cell.
  • the depth and width of the groove 105 are both variable to adapt to different flow channel widths and depths.
  • Too much water will block the channel through which the reactant gas flows, causing the gas diffusion rate in the gas diffusion layer to decrease.
  • the decrease in gas diffusion rate leads to a decrease in the rate of electrochemical reaction, and the performance of the fuel cell decreases.
  • the pressure at the inlet is greater than the pressure at the outlet.
  • first flow channel 102 and the second flow channel 103 are used to transport the same reaction gas along the first direction a.
  • the groove 105 extends along the second direction b.
  • the angle ⁇ between the second direction b and the first direction a is an acute angle.
  • the opening of the groove 105 in the first flow channel 102 is M.
  • the opening of the groove 105 in the second flow channel 103 is N. Because the first flow channel 102 and the second flow channel 103 are used to transport the same reaction gas along the first direction a.
  • the opening M is closer to the entrance, and the opening N is closer to the exit. Since the pressure at the inlet is greater than the pressure at the outlet, the pressure at the opening M is greater than the pressure at the opening N. Under the action of the pressure difference, the liquid water on the surface of the gas diffusion layer moves into the second flow channel 103, and continuously gathers at the outlet, and is taken away by the reaction gas and discharged.
  • the width of the flow channel in the bipolar plate flow field is about 0.4mm to 1.5mm, and the depth of the flow channel is about 0.4mm to 1.5mm.
  • the pressure drop at the inlet and outlet of the anode runner is about tens of kilopascals.
  • the width and depth of the reaction gas flow channel are both 1 mm, the width of the ridge is 1 mm, and the angle ⁇ formed by the chute and the length direction of the flow channel is 45°.
  • a plurality of the grooves 105 are provided on the bottom surface of the ridge 104.
  • a plurality of the grooves 105 are arranged at intervals to increase the number of diversion channels and improve the drainage rate. Further, the plurality of grooves 105 reduces the contact area between the ridge 104 and the gas diffusion layer, increases the contact area between air, hydrogen ions and electrons, thereby improving the performance of the fuel cell.
  • the distance L between two adjacent grooves 105 gradually decreases.
  • the flow channel is prone to local film drying near the inlet, and local water flooding is prone to occur near the outlet.
  • the distance L between the grooves 105 is smaller, and the number of the grooves 105 is increased, which can increase the diversion channel and increase the drainage rate.
  • the number of grooves 105 is reduced, which can reduce the gas purging area and avoid local film drying.
  • the groove 105 is not opened near the entrance, and a plurality of grooves 105 are opened near the exit to avoid local membrane drying at the entrance and local flooding at the exit.
  • the extending directions of the plurality of grooves 105 are different, and the included angle ⁇ with the first direction a gradually decreases. That is, the included angle ⁇ corresponding to the groove 105 near the entrance is relatively large, and the included angle ⁇ corresponding to the groove 105 near the exit is relatively small.
  • the smaller the included angle ⁇ the greater the component of the groove 105 in the length direction of the flow channel, the greater the pressure difference between the opening M and the opening N, and the greater the drainage rate.
  • the flow channel is prone to local film drying near the inlet, and local water flooding is prone to occur near the outlet.
  • the included angle ⁇ gradually decreases, increasing the pressure difference to increase the drainage rate.
  • the included angle ⁇ is small, which reduces the pressure difference and avoids local membrane drying.
  • the distance L between two adjacent grooves 105 gradually decreases, and the included angle ⁇ gradually decreases.
  • the number of the drainage channels increases, and the pressure difference between the opening M and the opening N increases, which improves the drainage rate and avoids local flooding of the outlet.
  • a first hole 70 is opened at the bottom of the groove 105, and the first hole 70 is in communication with the first flow channel 102, so as to increase the circulation channel and improve the drainage efficiency.
  • the first hole 70 includes a first hole 710 and a second hole 710 that intersect.
  • the first channel 710 communicates with the first flow channel 102.
  • the second channel 710 communicates with the second flow channel 103.
  • the opening of the first hole 70 at the bottom of the groove 105 is O, the opening of the first hole 70 in the first flow channel 102 is P, and the first hole 70 is in the second flow channel 103.
  • the opening is Q.
  • the cross-sectional shape of the opening P and the opening Q are the same, and are symmetrical with respect to the opening O.
  • the angle between the extending direction of the first flow channel 102 and the first direction a is a first angle.
  • the angle between the extending direction of the second flow channel 103 and the first direction a is a second angle.
  • the first included angle and the second included angle may be the same or different.
  • the groove 105 has a cut-off structure, which increases the pressure difference between the openings of the groove 105 and improves the drainage rate.
  • an embodiment of the present disclosure provides a fuel cell bipolar plate 10 including a substrate 100.
  • the surface of the substrate 100 is provided with a first flow channel 102 and a second flow channel 103 adjacent to each other.
  • a ridge 104 is formed between the first flow channel 102 and the second flow channel 103.
  • a second hole 80 is provided on the top surface of the ridge 104, and the second hole 80 is in communication with the first flow channel 102.
  • the fuel cell bipolar plate 10 provided by the embodiment of the present disclosure includes a substrate 100.
  • the second hole 80 is provided on the top surface of the ridge 104, and the second hole 80 communicates with the first flow channel 102. Water will penetrate into the groove 105, and then flow into the groove 105 through the groove 105.
  • the first flow channel 102 or the second flow channel 103 is carried away by the reaction gas.
  • the second hole 80 effectively avoids local water accumulation.
  • the fuel cell bipolar plate 10 increases the local circulation speed of the reaction gas, improves the combination efficiency of air, hydrogen ions and electrons, and further improves the performance of the fuel bipolar plate.
  • the second hole 80 reduces the contact area between the ridge 104 and the gas diffusion layer, increases the contact area between air, hydrogen ions and electrons, thereby improving the performance of the fuel cell.
  • the second hole 80 includes a third hole 810 and a fourth hole 820 that intersect.
  • the third channel 810 communicates with the first flow channel 102.
  • the fourth channel 820 communicates with the second flow channel 103.
  • the opening of the second hole 80 on the surface of the ridge 104 is O
  • the opening of the second hole 80 on the third channel 810 is P
  • the second hole 80 is on the surface of the fourth flow channel 820.
  • the opening is Q.
  • the cross-sectional shape of the opening P and the opening Q are the same, and are symmetrical with respect to the opening O.
  • the pressure of the opening P is equal to the pressure of the opening Q.
  • the length of the opening P from the outlet is greater than the length of the opening Q from the outlet, increasing the distance between the opening P and the opening Q
  • the pressure difference is convenient to improve the drainage efficiency and improve the performance of the bipolar plate.
  • a plurality of the second holes 80 are opened on the top surface of the ridge 104.
  • a plurality of the second holes 80 are arranged at intervals. In order to increase the number of diversion channels, improve the drainage rate. Further, the plurality of second holes 80 reduces the contact area between the ridge 104 and the gas diffusion layer, increases the contact area between air, hydrogen ions and electrons, thereby improving the performance of the fuel cell.
  • the distance L between two adjacent second holes 80 gradually decreases.
  • the flow channel is prone to local film drying near the inlet, and local water flooding is prone to occur near the outlet.
  • the distance L between the second holes 80 is smaller, and the number of the second holes 80 increases, which can increase the diversion channel and increase the drainage rate.
  • the number of the second holes 80 is reduced, which can reduce the gas purging area and avoid local membrane drying.
  • the second hole 80 is not opened near the entrance, and a plurality of second holes 80 are opened near the exit to avoid local membrane drying at the entrance and local flooding at the exit. .
  • a method for processing the fuel cell bipolar plate 10 described in any one of the above embodiments uses a laser engraving method to process the fuel cell bipolar plate.
  • the processing method includes: firstly, a flow channel with a rectangular cross section is processed by molding or machining, and then the groove 105, the first hole 70 or the second hole 80 is processed by an ultrafast laser. Because the laser processing is very flexible, the power is continuously adjustable, and no mechanical stress is generated during the processing, the shapes of the removed materials can be various, and a variety of the fuel cell bipolar plates 10 can be processed.
  • an embodiment of the present disclosure provides a fuel cell bipolar plate 10 including a substrate 100.
  • the substrate 100 includes a first surface 110.
  • the first surface 110 defines a flow channel 112.
  • the flow channel 112 is used for conveying reaction gas. Along the conveying direction A of the reaction gas in the flow channel 112, the cross-sectional area of the flow channel 112 gradually decreases.
  • the fuel cell bipolar plate 10 provided by an embodiment of the present disclosure.
  • the flow rate of the reaction gas in the flow channel 112 is constant. Along the conveying direction A of the reaction gas in the flow channel 112, the cross-sectional area of the flow channel 112 gradually decreases, the flow velocity of the reaction gas gradually increases, and the drainage rate of the flow channel 112 gradually increases.
  • the fuel cell bipolar plate 10 matches the drainage rate of each position of the flow channel 112 with the amount of liquid water, effectively avoiding partial membrane drying and partial flooding.
  • the fuel cell bipolar plate 10 ensures that no water accumulates in the gas diffusion layer, and the proton exchange membrane does not dry too much, the internal polarization loss of the fuel cell is reduced, and the performance of the fuel cell is improved.
  • the cross-sectional area of the flow channel 112 gradually decreases linearly.
  • the cross-sectional area of the flow channel 112 gradually decreases linearly.
  • the cross-sectional area of the flow channel 112 continuously and non-linearly decreases gradually.
  • the cross-sectional area of the flow channel 112 is continuously reduced according to a polynomial function, an exponential function, a logarithmic function, etc., or other irregularly continuous functions.
  • the cross-sectional area of the flow channel 112 gradually decreases in a stepped manner.
  • the cross-sectional shape of the flow channel 112 is a quadrilateral, a hexagon, an octagon, a decagon and other polygons.
  • the maximum width W of the cross section of the flow channel 112 gradually decreases, and the maximum depth H of the cross section of the flow channel 112 remains unchanged.
  • the cross-sectional shape of the flow channel 112 is a quadrilateral, a hexagon, an octagon, a decagon, or other polygons.
  • the maximum width W of the cross section of the flow channel 112 continuously linearly decreases, and the maximum depth H of the cross section of the flow channel 112 remains unchanged.
  • the cross-sectional shape of the flow channel 112 is a quadrilateral, a hexagon, an octagon, a decagon, or other polygons.
  • the maximum width W of the cross section of the flow channel 112 continuously and non-linearly decreases, and the maximum depth H of the cross section of the flow channel 112 remains unchanged.
  • the cross-sectional shape of the flow channel 112 is a quadrilateral, a hexagon, an octagon, a decagon, or other polygons.
  • the maximum width W of the cross section of the flow channel 112 decreases stepwise, and the maximum depth H of the cross section of the flow channel 112 remains unchanged.
  • the cross-sectional shape of the flow channel 112 is a quadrilateral, a hexagon, an octagon, a decagon, or other polygons.
  • the maximum width W of the cross section of the flow channel 112 remains unchanged, and the maximum depth H of the cross section of the flow channel 112 gradually decreases.
  • the cross-sectional shape of the flow channel 112 is a quadrilateral, a hexagon, an octagon, a decagon, or other polygons.
  • the maximum depth H of the cross section of the flow channel 112 continuously linearly decreases, and the maximum depth H and width W of the cross section of the flow channel 112 remain unchanged.
  • the cross-sectional shape of the flow channel 112 is a quadrilateral, a hexagon, an octagon, a decagon, or other polygons.
  • the maximum depth H of the cross section of the flow channel 112 continuously and non-linearly decreases, and the maximum width W of the cross section of the flow channel 112 remains unchanged.
  • the cross-sectional shape of the flow channel 112 is a quadrilateral, a hexagon, an octagon, a decagon, or other polygons.
  • the maximum depth H of the cross section of the flow channel 112 decreases stepwise, and the maximum width W of the cross section of the flow channel 112 remains unchanged.
  • the cross-sectional shape of the flow channel 112 is rectangular.
  • the width W of the cross section of the flow channel 112 gradually decreases, and the depth H of the cross section of the flow channel 112 remains unchanged.
  • the cross-sectional shape of the flow channel 112 is rectangular.
  • the width W of the cross section of the flow channel 112 continuously linearly decreases.
  • the depth H of the cross section of the flow channel 112 remains unchanged.
  • the cross-sectional shape of the flow channel 112 is rectangular.
  • the width W of the cross section of the flow channel 112 gradually decreases non-linearly, and the depth H of the cross section of the flow channel 112 remains unchanged.
  • the cross-sectional shape of the flow channel 112 is rectangular.
  • the width W of the cross section of the flow channel 112 gradually decreases stepwise, and the depth H of the cross section of the flow channel 112 remains unchanged.
  • the cross-sectional shape of the flow channel 112 is rectangular. Along the conveying direction A, the depth H of the cross section of the flow channel 112 gradually decreases, and the width W of the cross section of the flow channel 112 remains unchanged.
  • the cross-sectional shape of the flow channel 112 is rectangular.
  • the depth H of the cross section of the flow channel 112 gradually decreases linearly.
  • the width W of the cross section of the flow channel 112 remains unchanged.
  • the cross-sectional shape of the flow channel 112 is rectangular.
  • the depth H and width W of the cross section of the flow channel 112 gradually decrease non-linearly, and the width W of the cross section of the flow channel 112 remains unchanged.
  • the cross-sectional shape of the flow channel 112 is rectangular. Along the conveying direction A, the depth H and the width W of the cross section of the flow channel 112 gradually decrease stepwise, and the width W of the cross section of the flow channel 112 remains unchanged.
  • the cross-sectional shape of the flow channel 112 is rectangular. Along the conveying direction A, the depth H of the cross-section of the flow channel 112 gradually decreases, and the cross-section of the flow channel 112 The width W gradually decreases.
  • the manner in which the depth H of the cross section of the flow channel 112 is gradually reduced may be one of continuous linear reduction, continuous non-linear reduction, or stepwise reduction.
  • the width of the cross section of the flow channel 112 The way of gradually decreasing W may be one of continuous linear reduction, continuous non-linear reduction, or stepwise reduction.
  • the side wall of the flow channel 112 is arc-shaped.
  • a ridge 104 is formed between two adjacent flow channels 112, and the arc protrudes toward the ridge.
  • the bottom surface of the flow channel 112 is arc-shaped, and the bottom surface of the flow channel 112 is convex to the base.
  • the side wall or bottom surface of the flow channel 112 is arc-shaped.
  • the cross-sectional shape of the flow channel 112 remains unchanged, the maximum diameter width of the flow channel 112 gradually decreases, and the maximum depth H of the flow channel 112 remains unchanged.
  • the maximum diameter of the flow channel 112 decreases continuously linearly, continuously non-linearly, or decreases stepwise.
  • the side wall or bottom surface of the flow channel 112 is arc-shaped.
  • the cross-sectional shape of the flow channel 112 remains unchanged, the maximum depth H of the flow channel 112 gradually decreases, and the maximum diameter width of the flow channel 112 remains unchanged.
  • the maximum depth H of the flow channel 112 decreases continuously linearly, continuously non-linearly, or decreases stepwise.
  • the flow channel 112 includes an inlet, a middle, and an outlet.
  • only a portion of the flow channel 112 at the inlet gradually decreases in cross-sectional area, and a portion of the flow channel 112 at the middle and outlet has a cross-sectional area. constant.
  • the cross-sectional area of the part of the flow channel 112 at the inlet gradually decreases, which can refer to the cross-sectional area decrease mentioned above.
  • the cross-sectional area reduction method mentioned above can be referred to.
  • only a portion of the flow channel 112 at the outlet gradually decreases in cross-sectional area, and a portion of the flow channel 112 at the inlet and the middle has a cross-sectional area. constant.
  • the cross-sectional area of a part of the flow channel 112 at the outlet gradually decreases with reference to the cross-sectional area reduction method mentioned above.
  • the cross-sectional shape of the flow channel 112 may be changed, as long as the cross-sectional area of the flow channel 112 is gradually reduced.
  • an embodiment of the present disclosure provides a fuel cell bipolar plate 10 including a substrate 100.
  • the substrate 100 includes a first surface 110.
  • the first surface 110 defines a third flow channel unit 200.
  • the third flow channel unit 200 includes a plurality of third flow channels 210 arranged side by side.
  • a first ridge 220 is formed between two adjacent third flow channels 210.
  • the plurality of third flow passages 210 are used to transport the reaction gas along the first direction a.
  • the cross-sectional shape of the third flow channel 210 is rectangular.
  • the widths W of the plurality of first ridges 220 are equal, the width W of the section of the third flow channel 210 gradually decreases, and the depth H of the section of the third flow channel 210 remains unchanged.
  • the fuel cell bipolar plate 10 provided by an embodiment of the present disclosure.
  • the flow rate of the reaction gas in the third flow channel 210 is constant.
  • the widths W of the plurality of first ridges 220 are equal, the width W of the section of the third flow channel 210 gradually decreases, and the depth H of the section of the third flow channel 210 remains unchanged.
  • the cross-sectional area of the third flow channel 210 gradually decreases, the flow rate of the reaction gas gradually increases, and the drainage rate of the third flow channel 210 gradually increases.
  • the fuel cell bipolar plate 10 makes the drainage rate of each position of the third flow channel 210 match the amount of liquid water, effectively avoiding partial membrane drying and partial flooding.
  • the fuel cell bipolar plate 10 ensures that no water accumulates in the gas diffusion layer, and the proton exchange membrane does not dry too much, the internal polarization loss of the fuel cell is reduced, and the performance of the fuel cell is improved.
  • the first surface 110 is further provided with a fourth flow channel unit 300.
  • the fourth flow channel unit 300 includes a plurality of fourth flow channels 310 arranged side by side.
  • a second ridge 320 is formed between two adjacent fourth flow channels 310.
  • the plurality of fourth flow passages 310 are used to transport the reaction gas along the second direction b.
  • the second direction b is opposite to the first direction a.
  • the cross-sectional shape of the fourth flow channel 310 is rectangular.
  • the widths W of the plurality of second ridges 320 are equal, the width W of the cross section of the fourth flow channel 310 gradually decreases, and the depth H of the cross section of the fourth flow channel 310 remains unchanged.
  • the third flow channel unit 200 and the fourth flow channel unit 300 are centrally symmetrically distributed, which improves the utilization rate of the substrate 100 and facilitates the reduction of the volume of the fuel cell.
  • the third flow channel unit 200 and the fourth flow channel unit 300 are arranged in the middle of the first surface 110.
  • the fuel cell bipolar plate 10 also includes a first manifold group and a second manifold group.
  • the first manifold group and the second manifold group respectively include a first reactant intake manifold 610, a first reactant exhaust manifold 620, a second reactant exhaust manifold 630, A second reactant intake manifold 640 and a cooling water intake manifold 650.
  • the first manifold group and the second manifold group are centrally symmetrically arranged on both sides of the substrate 100.
  • the first reactant intake manifold 610 In the first manifold group, the first reactant intake manifold 610, the second reactant exhaust manifold 630, the cooling water intake manifold 650, the first reactant exhaust manifold The gas manifold 620 and a second reactant gas inlet manifold 640 are arranged in sequence.
  • the first reactant intake manifold 610 communicates with the intake port of the third runner unit 200.
  • the first reactant exhaust manifold 620 communicates with the exhaust port of the fourth runner unit 300.
  • a second reactant intake manifold 640, the first reactant exhaust manifold 620, the cooling water intake manifold 650, and the second reactant exhaust The manifold 630 and the first reactant intake manifold 610 are arranged in sequence.
  • the first reactant intake manifold 610 communicates with the intake port of the fourth runner unit 300.
  • the first reactant exhaust manifold 620 is in communication with the tapping port of the third runner unit 200.
  • the third flow channel 210 and the fourth flow channel 310 have the same cross-sectional shape and the same size.
  • the cross-sectional shape of the third flow channel 210 and the fourth flow channel 310 may be a polygonal structure such as a quadrilateral, a hexagon, or an octagon.
  • the cross-sectional shape of the third flow channel 210 and the fourth flow channel 310 may be different, and the size may be different.
  • an embodiment of the present disclosure provides a fuel cell bipolar plate 10 including a first substrate 400.
  • the first substrate 400 includes a first surface 110 and a second surface 140 opposite to each other.
  • the first surface 110 defines a third flow channel unit 200.
  • the third flow channel unit 200 includes a plurality of third flow channels 210 arranged side by side.
  • the third flow channel 210 is used to transport the reaction gas along the first direction a.
  • the cross-sectional shape of the third flow channel 210 is rectangular.
  • the cross-sectional shape of the third flow channel 210 does not change, the width W of the third flow channel 210 does not change, the depth of the third flow channel 210 gradually decreases, so The thickness T between the bottom surface of the third flow channel 210 and the second surface 140 is not changed to ensure the strength of the fuel cell bipolar plate 10.
  • the fuel cell bipolar plate 10 provided by an embodiment of the present disclosure.
  • the flow rate of the reaction gas in the third flow channel 210 is constant.
  • the cross-sectional shape of the third flow channel 210 is unchanged, the width W of the cross-section of the third flow channel 210 is unchanged, and the bottom surface of the third flow channel 210 and the second surface
  • the thickness between 140 is unchanged.
  • the cross-sectional area of the third flow channel 210 gradually decreases, the flow rate of the reaction gas gradually increases, and the drainage rate of the third flow channel 210 gradually increases.
  • the fuel cell bipolar plate 10 makes the drainage rate of each position of the third flow channel 210 match the amount of liquid water, effectively avoiding partial membrane drying and partial flooding.
  • the fuel cell bipolar plate 10 ensures that no water accumulates in the gas diffusion layer, and the proton exchange membrane does not dry too much, the internal polarization loss of the fuel cell is reduced, and the performance of the fuel cell is improved.
  • the fuel cell bipolar plate 10 further includes a second substrate 500.
  • the second substrate 500 includes a third surface 510 and a fourth surface 520 disposed opposite to each other.
  • the fourth surface 520 is attached to the second surface 140.
  • the third surface 510 defines a fourth flow channel unit 300.
  • the fourth flow channel unit 300 includes a plurality of fourth flow channels 310 arranged side by side.
  • the fourth flow channel 310 is used to transport the reaction gas along the second direction b.
  • the second direction b is opposite to the first direction a.
  • the cross-sectional shape of the fourth flow channel 310 is rectangular. Along the second direction b, the depth H of the cross section of the fourth flow channel 310 gradually decreases, and the width W of the cross section of the fourth flow channel 310 remains unchanged.
  • the thickness T between the four surfaces 520 remains unchanged.
  • the width W of the cross section of the third flow channel 210 remains unchanged, and the thickness T between the bottom surface of the third flow channel 210 and the second surface 140 remains unchanged.
  • the overall thickness of the first substrate 400 becomes smaller.
  • the width W of the cross section of the fourth flow channel 310 does not change, and the thickness T between the bottom surface of the third surface 510 and the fourth surface 120 does not change.
  • the overall thickness of the second substrate 500 becomes smaller.
  • the second substrate 500 and the first substrate 400 are arranged back to back, and the flow direction of the internal reactants is opposite.
  • the thicker part of the second substrate 500 corresponds to the thinner part of the first substrate 400, and the thinner part of the second substrate 500 corresponds to the thickness of the first substrate 400
  • the thicker part is provided to reduce the overall thickness of the fuel cell bipolar plate 10, which is convenient to reduce the volume of the fuel cell.
  • the third flow channel 210 and the fourth flow channel 310 have the same cross-sectional shape and the same size.
  • the cross-sectional shape of the third flow channel 210 and the fourth flow channel 310 may be a polygonal structure such as a quadrilateral, a hexagon, or an octagon.
  • the cross-sectional shape of the third flow channel 210 and the fourth flow channel 310 may be different, and the size may be different.
  • the depth H of the cross section of the third flow channel 210 gradually decreases, the width W of the cross section of the third flow channel 210 gradually decreases, and the third flow channel 210
  • the thickness T between the bottom surface of and the second surface 420 remains unchanged.
  • the depth H of the cross section of the fourth flow channel 310 gradually decreases, the width W of the cross section of the fourth flow channel 310 remains unchanged, and the thickness T between the bottom surface of the fourth flow channel 310 and the fourth surface 520 constant.
  • an embodiment of the present disclosure provides a method for processing a fuel cell bipolar plate 10.
  • the processing method includes: first, a rectangular cross-section flow channel is processed by molding or machining, and then an ultrafast laser is used to process the side surface of the ridge or the bottom surface of the flow channel. Because the laser processing is very flexible, the power is continuously adjustable, and the processing is not performed. Mechanical stress is generated, so the shape of the removed material can be varied, and a variety of non-rectangular cross-section flow channels and flow channels with cross-sectional areas varying in various forms can be processed.

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Abstract

一种燃料电池双极板加工方法。所述加工方法根据目标流道结构图（30），利用激光在所述石墨双极板毛坯上加工流道，得到成型石墨双极板。激光的光斑直径为微米级。所述加工方法利用激光进行流道加工，激光加工不产生机械应力，光斑直径小，因此激光能加工脊背宽度更窄，排布更紧密的流道。超密流道有利于反应气体的扩散，提高了双极板的性能。进一步的，所述加工方法还包括对所述成型石墨双极板进行表面洁净处理和表面疏水处理，表面疏水处理后的流道不易积水。所述加工方法加工形成的双极板流道的气体输送能力增强，所述加工方法提高了双极板性能。

Description

燃料电池双极板及其加工方法
相关申请
本公开要求2019年10月22日申请的，申请号为201911005875.X，名称为“燃料电池双极板加工方法”、2019年10月22日申请的，申请号为201911006524.0，名称为“燃料电池双极板及其加工方法”和2019年10月22日申请的，申请号为201911006521.7，名称为“燃料电池双极板”的中国专利申请的优先权，在此将其全文引入作为参考。
技术领域
本公开涉及燃料电池技术领域，特别是涉及一种燃料电池双极板及其加工方法。
背景技术
双极板是燃料电池的核心零部件，双极板的设计是决定燃料电池性能的核心因素。双极板表面开设阴极流道、阳极流道、冷却流道等结构。阴极与阳极流道结构承担燃料电池内反应气体分配、气体冷却、排水等功能。
发明人所了解的技术中通常通过机床加工和模压成型的方式进行双极板流道沟槽加工。降低流道脊背的宽度，可以提高反应气体向脊背下区域的扩散效率，因此提高流道排布的密集度可以提高燃料电池的性能。由于受到石墨材料脆性和加工模具的影响，机床加工和模压成型的方式很难加工脊背很窄的密集流道，导致现有主流产品的双极板流道的脊背宽度在1毫米水平，发明人所了解的技术中继续降低流道脊背宽度会大幅提高加工成本与加工时间。进一步突破燃料电池性能需要将双极板上流道脊背的宽度降低到0.2毫米至0.3毫米水平。
双极板上的流道承担着均匀分配气体反应物以及吹扫排出生成的水等多重任务。燃料电池运行时，在反应物气流的带动下，反应生成的水会向流道出口方向移动。从流道入口到流道出口，流道和气体扩散层内的液态水逐渐增加，液态水阻碍反应气体传递，提高气体在流道的传质与排水能力是提高燃料电池性能的关键。
发明内容
基于此，有必要针对怎样才能提高燃料电池的性能的问题，提供一种燃料电池双极板及其加工方法。
一种燃料电池双极板加工方法，包括：
提供石墨双极板毛坯。
根据目标流道结构图，绘制整体加工路径图。
根据所述整体加工路径图，利用激光在所述石墨双极板毛坯表面加工流道，得到成型石墨双极板。
对所述成型石墨双极板进行表面洁净处理和表面疏水处理。
本公开提供的所述燃料电池双极板加工方法包括获取石墨双极板毛坯。根据目标流道结构图，利用激光在所述石墨双极板毛坯上加工流道，得到成型石墨双极板。现有技术中刀具加工的流道脊背在毫米级宽度，模压的模具成型脊背宽度也为毫米级。所述加工方法利用激光进行流道加工，本公开中激光的光斑直径为微米级，不产生机械应力，激光能加工脊背宽度更窄，排布更紧密的流道。进一步的，所述加工方法还包括对所述成型石墨双极板进行表面洁净处理和表面疏水处理，表面疏水处理后的流道不易积水。进而，所述加工方法加工形成的双极板流道的输送能力增强，所述加工方法提高了双极板性能。
附图说明
图1为本公开一个实施例中提供的所述燃料电池双极板加工方法的电气原理图；
图2为本公开一个实施例中提供的所述目标流道结构图；
图3为本公开一个实施例中提供的所述整体加工路径图；
图4为本公开一个实施例中提供的所述A-A局部结构图；
图5为本公开一个实施例中提供的所述激光雕刻机的结构示意图；
图6为本公开一个实施例中提供的所述折射镜的位置示意图；
图7为本公开一个实施例中提供的所述成型石墨双极板的聚焦流道底部的影像图；
图8为本公开一个实施例中提供的所述燃料电池双极板的结构图；
图9为本公开一个实施例中提供的所述燃料电池双极板的俯视结构图；
图10为本公开一个实施例中提供的所述燃料电池双极板的A-A截面剖视图；
图11为本公开一个实施例中提供的所述脊开设斜槽的俯视结构图；
图12为本公开一个实施例中提供的所述凹槽底面开孔的俯视结构图；
图13为本公开一个实施例中提供的所述凹槽底面开孔的B-B截面剖视图；
图14为本公开一个实施例中提供的所述斜槽底面开孔的俯视结构图；
图15为本公开一个实施例中提供的所述脊开孔的俯视结构图；
图16为本公开另一个实施例中提供的所述脊开孔的俯视结构图；
图17为本公开一个实施例中提供的所述燃料电池双极板的结构图；
图18为本公开一个实施例中提供的流道宽度线性连续变化的结构图；
图19为本公开一个实施例中提供的所述燃料电池双极板的侧视结构图；
图20为本公开一个实施例中提供的流道宽度线性连续变化的A-A截面剖视图；
图21为本公开一个实施例中提供的流道截面形状为六边形；
图22为本公开一个实施例中提供的流道截面形状为八边形；
图23为本公开另一个实施例中提供流道宽度非线性连续变化的结构图；
图24为本公开另一个实施例中提供流道宽度阶梯型变化的结构图；
图25为本公开另一个实施例中提供流道深度线性连续变化的结构图；
图26为本公开另一个实施例中提供的流道深度线性连续变化的A-A截面剖视图；
图27为本公开另一个实施例中提供流道深度非线性连续变化的结构图；
图28为本公开另一个实施例中提供流道深度阶梯型变化的结构图；
图29为本公开一个实施例中提供的流道宽度和宽度都变化的结构图；
图30为本公开另一个实施例中提供的流道结构图；
图31为本公开另一个实施例中提供的流道结构图；
图32为本公开另一个实施例中提供的双极板的结构图；
图33为本公开一个实施例中提供的流道深度连续变化且底部厚度不变的结构图；
图34为本公开另一个实施例中提供的双极板的结构图；
图35为本公开另一个实施例中提供的双极板的结构图；
图36为本公开另一个实施例中提供的激光加工示意图。
附图标号:
燃料电池双极板10 基板100 扩散层101 第一流道102 第二流道103 第一表面110 脊104 凹槽105 第二表面140 流道112 入口121 出口122 脊104 输送方向A 第一方向a 第二方向b 夹角θ 间距L 宽度W 深度H 厚度T 第三流道单元200 第三流道210 第一脊220 第四流道单元300 第四流道310 第二脊320 第一基板400 第二基板500 第三表面510 第四表面520 第一反应物进气歧管610 第一反应物排气歧管620 第二反应物排气歧管630 第二反应物进气歧管640 冷却水进歧管650 第一孔70 第一孔道710 第二孔道720 第二孔80 第一孔道810 第二孔道820 激光发生器120 移动结构130 平台131 折射镜150 目标流道结构图30 目标流道300 流道间距D 第一目标流道310 第二目标流道320 第一目标流道起点B 整体加工路径图40 扫描线组400 扫描组间距h1 扫描线间距h2 弧形倒角结构402 第一扫描线组410 第一扫描线411 第一扫描线起点b 第二扫描线组420 第二扫描线421
具体实施方式
为使本公开的上述目的、特征和优点能够更加明显易懂，下面结合附图对本公开的具体实施方式做详细的说明。在下面的描述中阐述了很多具体细节以便于充分理解本公开。但是本公开能够以很多不同于在此描述的其它方式来实施，本领域技术人员可以在不违背本公开内涵的情况下做类似改进，因此本公开不受下面公开的具体实施的限制。
本文中为部件所编序号本身，例如“第一”、“第二”等，仅用于区分所描述的对象，不具有任何顺序或技术含义。而本公开所说“连接”、“联接”，如无特别说明，均包括直接和间接连接(联接)。在本公开的描述中，需要理解的是，术语“上”、“下”、“前”、“后”、“左”、“右”、“竖直”、“水平”、“顶”、“底”、“内”、“外”、“顺时针”、“逆时针”等指示的方位或位置关系为基于附图所示的方位或位置关系，仅是为了便于描述本公开和简化描述，而不是指示或暗示所指的装置或元件必须具有特定的方位、以特定的方位构造和操作，因此不能理解为对本公开的限制。
在本公开中，除非另有明确的规定和限定，第一特征在第二特征“上”或“下”可以是第一和第二特征直接接触，或第一和第二特征通过中间媒介间接接触。而且，第一特征在第二特征“之上”、“上方”和“上面”可是第一特征在第二特征正上方或斜上方，或仅仅表示第一特征水平高度高于第二特征。第一特征在第二特征“之下”、“下方”和“下面”可以是第一特征在第二特征正下方或斜下方，或仅仅表示第一特征水平高度小于第二特征。
基于提高气体在流道的传质与排水能力才能提高燃料电池性能，有必要提供一种燃料电池双极板加工方法。
双极板是燃料电池的核心零部件，双极板的设计是决定燃料电池性能的核心因素。双极板具有阴极流道、阳极流道、冷却流道等结构。双极板承担燃料电池内反应气体分配、冷却、排水等功能。
石墨双极板的耐腐蚀能力强。通常使用石墨双极板来设计长寿命燃料电池电堆。为了提高双极板的性能，技术人员将脊背的宽度不断变窄与密度不断提高。现有的双极板槽深槽宽通常都在1毫米水平，部分加工工艺可以达到0.4mm。但是，无论是使用数控机床加工还是模压成型，进一步降低脊背的宽度和提高流道的密度都存在成本高与效率低的问题。
请参见图1、图2和图3，本公开实施例提供一种燃料电池双极板加工方法，包括：
S100，提供石墨双极板毛坯。
S200，根据目标流道结构图1，绘制整体加工路径图40。
S300，根据所述整体加工路径图40，利用激光在所述石墨双极板毛坯表面加工流道，得到成型石墨双极板。
S400，对所述成型石墨双极板进行表面洁净处理和表面疏水处理。
本公开实施例提供的所述燃料电池双极板加工方法，根据目标流道结构图1，利用激光在所述石墨双极板毛坯上加工流道，得到成型石墨双极板。发明人所了解的技术中刀具加工的流道脊背在毫米级宽度，模压的模具成型脊背宽度也为毫米级。所述加工方法利用激光进行流道加工，本公开中激光的光斑直径为微米级，不产生机械应力，激光能加工脊背宽度更窄，排布更紧密的流道。进一步的，所述加工方法还包括对所述成型石墨双极板进行表面洁净处理和表面疏水处理，表面疏水处理后的流道不易积水。进而，所述加工方法加工形成的双极板流道的输送能力增强，所述加工方法提高了双极板性能。
在一个实施例中，在所述S100步骤包括加工形成硬质双极板原始毛坯。采用机械加工机床在所述硬质双极板原始毛坯表面开设进出口和公共流道气孔，以形成石墨双极板毛坯。
在另一个实施例中，在所述S100步骤包括采用石墨粉模压形成所述石墨双极板毛坯，所述石墨双极板毛坯表面已开设进出口、公共流道气孔和主流道。通过模压成型方法形成 所述主流道。通过所述S200对所述石墨双极板毛坯表面的主流道进行精细加工，以提高主流道的气体扩散能力。
采用所述机械加工和所述模压成型方法加工双极板的进出口公共流道气孔，提高了加工效率。
激光雕刻的原理是使用高能的激光光束，来融化燃烧激光扫过路径的石墨与树脂材料，形成流道沟槽。
在一个实施例中，所述S200包括：
S210，根据所述目标流道结构图1，获取目标流道300的流道宽度、流道深度、流道延伸形状和流道间距D。
S220，根据所述流道宽度选取激光的光斑直径和走光间距。
S230，根据所述流道深度选取扫描频率、走光速度和加工扫描次数。
S240，根据所述流道延伸形状、所述流道间距D、所述光斑直径和所述走光间距，得到所述整体加工路径图40。
所述流道间距D指相邻两个流道之间相邻侧壁之间的距离。所述走光间距指相邻两个扫描光斑的中点之间的距离，其中所述相邻两个扫描光斑用于加工相邻两条扫描线。
请一并参见图4，在一个实施例中，所述S240包括：
S241，所述目标流道结构图1包括多条目标流道300，所述整体加工路径图40包含多个扫描线组400，所述多个扫描线组400与所述多条目标流道300一一对应设置，每个所述扫描线组400包含多条扫描线，根据所述流道延伸形状，得到与所述目标流道300对应的所述扫描线的形状。
S242，根据所述光斑直径、所述走光间距和所述流道宽度计算每条所述目标流道300的走光次数，根据所述走光次数得到所述扫描线的条数，根据所述走光间距得到对应的相邻两条所述扫描线的扫描线间距h2，相邻两条所述扫描线位于一个所述扫描线组400。
S243，根据所述流道间距D得到对应的相邻两个所述扫描线组400的扫描组间距h1。
S244，根据所述扫描线的形状、所述扫描线的条数、所述扫描线间距h2和所述扫描组间距h1，得到所述整体加工路径图40。
在所述S241，一个所述扫描线组400的多条所述扫描线平行设置。所述扫描线的形状包括直线形、折线形和弧线形。
在所述S242，利用走光次数公式可以得到所述走光次数。所述走光次数公式为：
n＝(X-Y)/(p+1)
其中，n表示所述走光次数，X表示所述流道宽度，Y表示所述光斑直径，p表示所述走光间距。
所述走光间距的选取基于所述石墨双极板毛坯的激光加工特性。合适的所述走光间距既能保证加工速度，也能保证表面粗糙度。
在一个实施例中，在选取所述走光间距前，需进行走光间距预备实验。所述光间距预备实验包括多次采用不同的所述走光间距进行多个激光加工，并测量所述流道的表面的加工精度。
在上一个实施例中，所述走光间距等于所述扫面线间距。
在一个实施例中，所述S300为根据所述光斑直径、所述扫描频率、所述走光速度、所述加工扫描次数和所述整体加工路径图40，利用激光在所述石墨双极板毛坯上加工流道，得到所述成型石墨双极板。
请一并参见图5，在一个实施例中，采用激光雕刻机对所述石墨双极板毛坯进行加工。所述激光雕刻机包括整体控制装置、激光发生器120、平台131和移动结构130。所述激光发生器120和所述移动结构130分别与所述整体控制装置电连接。所述整体控制装置用于接收外部命令，并根据所述外部命令控制所述激光发生器120和所述移动结构130协同工作。
所述激光发生器120用于产生激光。所述平台131用于固定所述石墨双极板毛坯，并提供加工平台。所述移动结构130与所述激光发生器120的探头121固定连接，用于带动所述激光探头121按照所述整体加工路径图40移动。所述移动结构130具备空间三维移动功能。
在一个实施例中，所述激光雕刻机对所述石墨双极板毛坯进行加工的步骤包括：
S1，将所述石墨双极板毛坯固定于所述平台131，所述石墨双极板毛坯标记有加工原点，所述探头121与所述石墨双极板毛坯的加工原点对应设置。
S2，在所述整体控制装置上设置所述光斑直径、所述扫描频率、所述走光速度、所述加工扫描次数。
S3，将所述整体加工路径图40导入所述整体控制装置。
S4，所述整体控制装置控制所述激光发生器120和所述移动结构130协同工作，对所述石墨双极板毛坯表面进行流道加工。
请一并参见图6，在一个实施例中，所述激光雕刻机还包括折射镜150。所述折射镜150设置于所述激光路径上，用于改变所述激光的方向。利用所述激光雕刻机可以加工的多种所述目标流道。所述目标流道可以是脊背上的斜孔，梯形槽等空间结构。
相邻两个所述目标流道300之间形成脊，上述方法还用于加工脊上开孔、开槽及其结合的结构。
在一个实施例中，在所述S230步骤之前，所述加工方法还包括：
S221，进行预扫描实验，以确定所述扫描频率、所述走光速度和所述加工扫描次数。
由于石墨板中树脂等非石墨部分的比例不一样，所述扫描频率、所述走光速度和所述加工扫描次数需要通过上述预备实验完成。在选取具体参数时，要充分协调加工精度、表面粗糙度与扫描参数之间的关系。
在一个实施例中，所述S221包括：
S11，获取实验石墨双极板毛坯，所述实验石墨双极板毛坯与待加工的所述石墨双极板毛坯相同。
S12，采用所述扫描频率和所述走光速度对所述实验石墨双极板毛坯进行第一次直线扫描，第一次实验加工扫描次数为N，得到第一凹槽，测量所述第一凹槽的深度，并得到第一深度。
S13，采用所述扫描频率和所述走光速度对所述实验石墨双极板毛坯进行第二次直线扫描，第二次实验加工扫描次数为M，得到第二凹槽，测量所述第二凹槽的深度，并得到第二深度，其中M大于N，其中M和N为正整数。
S14，根据所述第一深度、所述第二深度、M、N和所述流道深度，确定所述加工扫描次数。
在一个实施例中，在所述S4中，根据所述第一深度、所述第二深度、M、N和所述流道深度，采用差分法确定所述加工扫描次数，提高扫描精度。
所述走光速度越快整体的加工速度越快。所述走光速度的选取取决于设备的精度和流道加工的设计能力。当流道中存在垂直结构、多个断点、多段加工路径、与光斑同尺寸的微流道结构等复杂结构的加工需求时，采用可变的所述走光速度的方法。在加工直线流道时，采用第一走光速度。在加工复杂结构流道时，采用第二走光速度。所述第一走光速度大于所述第二走光速度。
在一个实施例中，在所述S200中采用高能激光器对所述石墨双极板毛坯进行流道加工。高能激光加工石墨双极板时，石墨双极板的材料变化为气化的等离子状态，避免加工残渣残留堆积，产生加工缺陷。激光脉冲时间越短，整体能量越高，更有利于等离子化，低脉冲激光无法具备足够高的能量等离子体化石墨。
激光加工的流道深度与单位时间发射激光可以融化烧灼的石墨体积相对应。流道加工是加工速度与精度的平衡选择。能量越大，扫描越快，加工速度越快，精度越低。
在一个实施例中，所述高能激光器为皮秒激光器、飞秒激光器和纳秒激光器。
所述燃料电池双极板加工方法采用10微米到200微米水平的小光斑激光。由于激光雕刻的光斑能量分布服从高斯分布，越靠近所述激光光斑的中央，激光的能量越高。采用小光斑，能够缩减能量分布差异，提高加工精度。
在一个实施例中，在所述S200采用光纤激光器对所述石墨双极板毛坯进行流道加工。用于石墨加工的激光波长应当能量较大，波长较短。CO2激光的波长太长，能量较小，不适合进行石墨加工。光纤激光器的波长短，能量大，适用于石墨加工。
在所述S200中也可以采用比光纤激光波长更短的激光进行加工。
在一个实施例中，在所述S241中，根据所述目标流道300的延伸形状，得到对所述目标流道300对应的所述扫描线的形状的步骤还包括：
S21，判断所述目标流道300中是否包含拐角结构。
S22，若是，则与所述拐角结构对应的所述扫描线为弧形倒角结构402。
在一个实施例中，所述目标流道300包括直角流道结构，将所述直角流道结构设计为所述弧形倒角结构402，避免局部位置重复加工，提高加工精度。
在一个实施例中，所述多条目标流道300包括第一目标流道310和第二目标流道320，所述多个扫描线组400包含第一扫描线组410和第二扫描线组420，所述第一扫描线组410包含多个第一扫描线411，所述第一扫描线411与所述第一目标流道310对应，所述第二扫描线组420包含多个第二扫描线421，所述第二扫描线421与所述第二目标流道320对应，在所述S241中，根据所述目标流道300的延伸形状，得到对所述目标流道300对应的所述扫描线的形状的步骤还包括：
S31，判断所述第一目标流道起点B是否与所述第二目标流道320的延伸路径重叠。
S32，若是，所述第一扫描线起点b设置加工余量间隙。
如果将第一扫描线411与所述第二扫描线421重叠，则在重叠部位，激光扫描两次，重叠部位的加工深度大于其他部位的深度。设置所述加工余量间隙，即在所述第一扫描线起点b距离所述第二扫描线421设置一定间隙，以保证光斑中心不会重复扫描间隙位置，提高加工精度。所述间隙的长度与光斑半径在同一量级水平。
请一并参见图7，在一个实施例中，实验使用了普通的膨胀石墨板和80W皮秒激光器，使用了固定所述走光速度1m/s，预备实验中50％能量扫描100次，得到所述流道深度约为0.2mm。采用40％能量扫描500次，得到所述流道深度约为0.75mm。采用差分法，得到所述流道深度为0.3mm，使用50％能量，每条所述扫描线扫描150次。
在一个实施例中，设计目标是0.3mm宽，0.3mm深的流道。基于预备实验的结果，最终设计流道如下：
所述光斑直径为50um；所述扫描间距为20um；所述扫描频率为300kHz；所述扫描次数为每条所述扫描线扫描150次；所述扫描速度为1m/s；所述扫描能量为50％(最大80W)。
图7为利用上述参数得到的所述成型石墨双极板的聚焦流道底部101的影像图。成型的流道112底部平整度良好。相邻两个所述流道112之间形成脊104。
在一个实施例中，提供一种燃料电池双极板包括基板。所述基板的表面开设相邻的第一流道和第二流道。所述第一流道和所述第二流道之间形成脊。在所述脊的顶面开设凹槽，且所述第一流道或所述第二流道中的一个或两个流道与所述凹槽连通。
本公开实施例提供的所述燃料电池双极板包括基板。所述基板的表面开设相邻的第一流道和第二流道。所述第一流道和所述第二流道之间形成脊。在所述脊的顶面开设凹槽，且所述第一流道或所述第二流道中的一个或两个流道与所述凹槽连通。所述脊与阴极扩散层的接触部位积累的水会渗入所述凹槽，再通过所述凹槽流入所述第一流道或第二流道，并被反应气体带走。所述凹槽有效避免了局部水堆积，从而提高燃料电池内部的排水性能。所述燃料电池双极板提高了反应气体的局部流通速度，提高了反应气体通过扩散层的传质效率，进而提高了燃料电池的性能。进一步的，所述凹槽减小了双极板脊部与气体扩散层 的接触面积，提高了气体扩散层内气体扩散的有效面积，从而提高所述燃料电池的性能。
在一个实施例中，燃料电池在工作中发生电化学反应，在阴极催化剂层生成水。反应生成的水通过扩散层到达流道，被流道内的反应气体带走。反应气体在流道和气体扩散层中流动。相对于流道内部，所述脊与阴极扩散层的接触表面阻碍扩散层中的水进入流道，水在接触部位滞留，阻碍反应气体从流道向催化剂层传质，从而影响燃料电池的工作性能。
请参见图8、图9和图10，本公开实施例提供一种燃料电池双极板10包括基板100。所述基板100的表面开设相邻的第一流道102和第二流道103。所述第一流道102和所述第二流道103之间形成脊104。在所述脊104的顶面开设凹槽105，且所述第一流道102或所述第二流道103中的一个或两个流道与所述凹槽105连通。
本公开实施例提供的所述燃料电池双极板10包括基板100。在所述脊104的顶面开设所述凹槽105，且所述第一流道102或所述第二流道103中的一个或两个流道与所述凹槽105连通。水会渗入所述凹槽105，再通过所述凹槽105流入所述第一流道102或第二流道103，并被反应气体带走。所述凹槽105有效避免了局部水堆积，从而提高燃料电池内部的排水性能。所述燃料电池双极板10提高了反应气体的局部流通速度，提高了反应气体通过扩散层的传质效率，进而提高了燃料电池的性能。进一步的，所述凹槽105减小了所述脊104与气体扩散层101的接触面积，提高了气体扩散层101内气体扩散的有效面积，从而提高所述燃料电池的性能。
所述凹槽105的截面形状可以为多变形、圆形或部分弧形。所述凹槽105与所述第一流道102或所述第二流道103连通，将所述凹槽105附近的水引入所述第一流道102或所述第二流道103中，减少了局部水堆积，提高了气体、氢离子和电子的接触几率，进而提高了所述燃料电池的性能。所述凹槽105的深度和宽度均可变，以适应不同流道宽度和深度。
燃料电池运行时，在阴极侧催化剂层会发生电化学反应生成水。水通过阴极扩散层进入阴极流道，或通过质子交换膜扩散到阳极，再通过阳极气体扩散层进入阳极流道。在反应气体气流的带动下，流道中的水向流道的出口移动。沿气流的运动方向，流道中的水量逐渐增加。所述流道的出口的水量大于入口的水量。所述流道靠近所述入口处容易发生局部膜干，靠近所述出口处容易发生局部水淹。水量过少会导致质子交换膜的电导率减小。水量过多会堵塞反应气体流动的通道，造成气体扩散层内的气体扩散速率下降。气体扩散速率下降导致电化学反应的速率降低，燃料电池的性能下降。为了使反应气体沿流道流动，入口处的压力大于出口处的压力。
请一并参见图11，在一个实施例中，所述第一流道102和所述第二流道103用于沿第一方向a输送相同的反应气体。所述凹槽105沿第二方向b延伸。所述第二方向b与所述第一方向a之间的夹角θ为锐角。
所述凹槽105在所述第一流道102的开口为M。所述凹槽105在所述第二流道103的开口为N。由于所述第一流道102和所述第二流道103用于沿第一方向a输送相同的反应气体。开口M更靠近入口处，开口N更靠近出口处。又由于入口处压力大于出口处压力，故开口M的压力大于开口N的压力。在压力差的作用下，气体扩散层表面的液态水运动到第二流道103中，并不断汇集到出口处，被反应气体带走排出。
一般地，双极板流场中流道的宽度约为0.4mm至1.5mm，流道深度约为0.4mm至1.5mm。阳极流道进出口的压降约为几十千帕。在一个具体实施例中，以阳极为例，反应气体流道的宽度和深度均为1mm，脊部的宽度为1mm，斜槽与流道长度方向所成角度θ为45°。取流道进出口的压降为30kPa，则对于一个总长度300mm的气体流道，斜槽两端的压差为30kPa/300＝100Pa。
在一个实施例中，在所述脊104的底面开设多个所述凹槽105。沿所述第一方向a，多个所述凹槽105间隔排布，以增加导流通道的个数，提高排水速率。进一步的，多个所述凹槽105减小了所述脊104与气体扩散层的接触面积，提高了空气、氢离子和电子的接触 面积，从而提高所述燃料电池的性能。
在一个实施例中，沿所述第一方向a，相邻两个所述凹槽105之间的间距L逐渐减小。所述流道靠近所述入口处容易发生局部膜干，靠近所述出口处容易发生局部水淹。在靠近所述出口处，所述凹槽105之间的间距L更小，所述凹槽105的数量增多，能够增加导流通道，增加排水速率。在靠近所述入口处，所述凹槽105的数量减小，能够减少气体吹扫面积，避免发生局部膜干。
在一个实施例中，靠近所述入口处不开设所述凹槽105，靠近所述出口处开设多个所述凹槽105，以避免入口处发生局部膜干，出口处发生局部水淹。
在一个实施例中，沿气体流通方向，多个所述凹槽105的延伸方向不同，与所述第一方向a的夹角θ逐渐变小。即靠近入口处的所述凹槽105对应的夹角θ较大，靠近出口处的所述凹槽105对应的夹角θ较小。所述夹角θ越小，则所述凹槽105在流道长度方向的分量越大，开口M与开口N之间的压差越大，排水速率越大。所述流道靠近所述入口处容易发生局部膜干，靠近所述出口处容易发生局部水淹。在靠近所述出口处，所述夹角θ逐渐变小，增大压差增加排水速率。在靠近所述入口处，所述夹角θ较小，减小压差，避免发生局部膜干。
在一个实施例中，沿所述第一方向a，相邻两个所述凹槽105之间的间距L逐渐减小，所述夹角θ逐渐减小。在靠近所述出口处，所述排水通道的数量增加，开口M和开口N的压差增大，提高了排水速率，避免所述出口发生局部水淹。
请一并参见图12，在一个实施例中，所述凹槽105的底部开设第一孔70，且所述第一孔70与所述第一流道102连通，以增加流通通道，提高排水效率。
请一并参见图12和图13，在一个实施例中，所述第一孔70包括相交的第一孔道710和第二孔道710。所述第一孔道710与所述第一流道102连通。所述第二孔道710与所述第二流道103连通。所述第一孔70在所述凹槽105底部的开口为O，所述第一孔70在所述第一流道102的开口为P，所述第一孔70在所述第二流道103的开口为Q。
在一个实施例中，所述开口P与所述开口Q的截面形状相同，且关于所述开口O对称。
所述第一流道102的延伸方向与所述第一方向a的夹角为第一夹角。所述第二流道103的延伸方向与所述第一方向a的夹角为第二夹角。所述第一夹角与所述第二夹角可以相同，也可以不同。
请一并参见图14，在上一个实施例中，所述凹槽105为切斜结构，增加所述凹槽105开口之间的压力差，提高排水速率。
请参见图15和图16，本公开实施例提供一种燃料电池双极板10包括基板100。所述基板100的表面开设相邻的第一流道102和第二流道103。所述第一流道102和所述第二流道103之间形成脊104。在所述脊104的顶面开设第二孔80，且所述第二孔80与所述第一流道102连通。
本公开实施例提供的所述燃料电池双极板10包括基板100。在所述脊104的顶面开设所述第二孔80，且所述第二孔80与所述第一流道102连通水会渗入所述凹槽105，再通过所述凹槽105流入所述第一流道102或第二流道103，并被反应气体带走。所述第二孔80有效避免了局部水堆积。所述燃料电池双极板10提高了反应气体的局部流通速度，提高了空气、氢离子和电子的结合效率，进而提高了燃料双极板的性能。进一步的，所述第二孔80减小了所述脊104与气体扩散层的接触面积，提高了空气、氢离子和电子的接触面积，从而提高所述燃料电池的性能。
在一个实施例中，所述第二孔80包括相交的第三孔道810和第四孔道820。所述第三孔道810与所述第一流道102连通。所述第四孔道820与所述第二流道103连通。所述第二孔80在所述脊104表面的开口为O，所述第二孔80在所述第三孔道810的开口为P，所述第二孔80在所述第四流道820的开口为Q。
在一个实施例中，所述开口P与所述开口Q的截面形状相同，且关于所述开口O对称。所述开口P的压强与所述开口Q的压强相等。
在一个实施例中，沿所述第一方向a，所述开口P距离所述出口处的长度大于所述开口Q距离所述出口处的长度，增加所述开口P与所述开口Q之间的压差，便于提高排水效率，提高双极板的性能。
在一个实施例中，在所述脊104的顶面开设多个所述第二孔80。沿所述第一方向a，多个所述第二孔80间隔排布。以增加导流通道的个数，提高排水速率。进一步的，多个所述第二孔80减小了所述脊104与气体扩散层的接触面积，提高了空气、氢离子和电子的接触面积，从而提高所述燃料电池的性能。
在一个实施例中，沿所述第一方向a，相邻两个所述第二孔80之间的间距L逐渐减小。所述流道靠近所述入口处容易发生局部膜干，靠近所述出口处容易发生局部水淹。在靠近所述出口处，所述第二孔80之间的间距L更小，所述第二孔80的数量增多，能够增加导流通道，增加排水速率。在靠近所述入口处，所述第二孔80的数量减小，能够减少气体吹扫面积，避免发生局部膜干。
在一个实施例中，靠近所述入口处不开设所述第二孔80，靠近所述出口处开设多个所述第二孔80，以避免入口处发生局部膜干，出口处发生局部水淹。
一种上述任意一个实施例所述的燃料电池双极板10的加工方法，采用激光雕刻法加工所述燃料电池双极板。所述加工方法包括：首先，通过模压或机加工加工出矩形截面的流道，再使用超快激光加工所述凹槽105、所述第一孔70或所述第二孔80。由于激光加工非常灵活、功率连续可调且加工过程中不产生机械应力，因此去除的材料的形状可以多种多样，进而加工出多种所述燃料电池双极板10。
燃料电池运行时，在双极板的阴极侧流道会发生化学反应生成水。在反应气体气流的带动下，流道中的水向所述流道112的出口移动。沿气流的运动方向，流道中的水量逐渐增加。所述流道112的出口122的水量大于入口121的水量。所述流道112靠近所述入口121处容易发生局部膜干，靠近所述出口122处容易发生局部水淹。水量过多会造成气体扩散层内的气体扩散速率下降，水量过少会导致质子交换膜的质子传递阻抗增大，二者都会导致燃料电池的极化损失增大、性能下降。
请参见图17、图18、图19和图20，本公开实施例提供一种燃料电池双极板10包括基板100。所述基板100包括第一表面110。所述第一表面110开设流道112。所述流道112用于输送反应气体。沿着所述反应气体在所述流道112的输送方向A，所述流道112的截面面积逐渐减小。
本公开实施例提供的所述燃料电池双极板10。所述流道112中反应气体的流量一定。沿着所述反应气体在所述流道112的输送方向A，所述流道112的截面面积逐渐减小，所述反应气体流速逐渐增大，所述流道112的排水速率逐渐增大。所述燃料电池双极板10使得所述流道112各位置的排水速率与液态水量相匹配，有效避免局部膜干和局部水淹。所述燃料电池双极板10保证气体扩散层内不发生积水的同时质子交换膜不会过干，燃料电池内部极化损失降低，提高了燃料电池的性能。
在一个实施例中，沿所述反应气体的输送方向A，所述流道112的截面面积连续线性逐渐减小。
在一个实施例中，沿所述反应气体的输送方向A，所述流道112的截面面积连续线性逐渐减小。
在一个实施例中，沿所述反应气体的输送方向A，所述流道112的截面面积连续非线性逐渐减小。
所述流道112的截面面积按照多项式函数、指数函数、对数函数等或其他不规则连续减小的函数。
在一个实施例中，沿所述反应气体的输送方向A，所述流道112的截面面积阶梯型逐 渐减小。
请一并参见图21和图22，在一个实施例中，所述流道112的截面形状为四边形、六边形、八边形、十边形等其他多边形。沿所述输送方向A，所述流道112截面的最大宽度W逐渐减小，所述流道112截面的最大深度H不变。
在一个实施例中，所述流道112的截面形状为四边形、六边形、八边形、十边形等其他多边形。沿所述输送方向A，所述流道112截面的最大宽度W连续线性减小，所述流道112截面的最大深度H不变。
在一个实施例中，所述流道112的截面形状为四边形、六边形、八边形、十边形等其他多边形。沿所述输送方向A，所述流道112截面的最大宽度W连续非线性减小，所述流道112截面的最大深度H不变。
在一个实施例中，所述流道112的截面形状为四边形、六边形、八边形、十边形等其他多边形。沿所述输送方向A，所述流道112截面的最大宽度W阶梯型减小，所述流道112截面的最大深度H不变。
在一个实施例中，所述流道112的截面形状为四边形、六边形、八边形、十边形等其他多边形。沿所述输送方向A，所述流道112截面的最大宽度W不变，所述流道112截面的最大深度H逐渐减小。
在一个实施例中，所述流道112的截面形状为四边形、六边形、八边形、十边形等其他多边形。沿所述输送方向A，所述流道112截面的最大深度H连续线性减小，所述流道112截面的最大深度H宽度W不变。
在一个实施例中，所述流道112的截面形状为四边形、六边形、八边形、十边形等其他多边形。沿所述输送方向A，所述流道112截面的最大深度H连续非线性减小，所述流道112截面的最大宽度W不变。
在一个实施例中，所述流道112的截面形状为四边形、六边形、八边形、十边形等其他多边形。沿所述输送方向A，所述流道112截面的最大深度H阶梯型减小，所述流道112截面的最大宽度W不变。
在一个实施例中，所述流道112的截面形状为矩形。沿所述输送方向A，所述流道112截面的宽度W逐渐减小，所述流道112截面的深度H不变。
在一个实施例中，所述流道112的截面形状为矩形。沿所述输送方向A，所述流道112截面的宽度W连续线性逐渐减小。所述流道112截面的深度H不变。
请一并参见图23，在一个实施例中，所述流道112的截面形状为矩形。沿所述输送方向A，所述流道112截面的宽度W连续非线性逐渐减小，所述流道112截面的深度H不变。
请一并参见图24，在一个实施例中，所述流道112的截面形状为矩形。沿所述输送方向A，所述流道112截面的宽度W阶梯型逐渐减小，所述流道112截面的深度H不变。
请一并参见图25和图26，在一个实施例中，所述流道112的截面形状为矩形。沿所述输送方向A，所述流道112截面的深度H逐渐减小，所述流道112截面的宽度W不变。
在一个实施例中，所述流道112的截面形状为矩形。沿所述输送方向A，所述流道112截面的深度H连续线性逐渐减小。所述流道112截面的宽度W不变。
请一并参见图27，在一个实施例中，所述流道112的截面形状为矩形。沿所述输送方向A，所述流道112截面的深度H宽度W连续非线性逐渐减小，所述流道112截面的宽度W不变。
请一并参见图28，在一个实施例中，所述流道112的截面形状为矩形。沿所述输送方向A，所述流道112截面的深度H宽度W阶梯型逐渐减小，所述流道112截面的宽度W不变。
请一并参见图29，在一个实施例中，所述流道112的截面形状为矩形，沿所述输送方向A，所述流道112截面的深度H逐渐减小，所述流道112截面的宽度W逐渐减小。
上一个实施例中，所述流道112截面的深度H逐渐减小的方式可以为连续线性减小、连续非线性减小或阶梯型减小中的一种，所述流道112截面的宽度W逐渐减小的方式可以为连续线性减小、连续非线性减小或阶梯型减小中的一种。
请一并参见图30，在一个实施例中，所述流道112的侧壁为弧形。相邻两个所述流道112之间形成脊104，所述弧向脊凸起。
请一并参见图31，在一个实施例中，所述流道112的底面为弧形，所述流道112的底面向基体凸起。
在一个实施例中，所述流道112的侧壁或底面为弧形。沿所述输送方向A，所述流道112的截面形状不变，所述流道112的最大径宽逐渐减小，所述流道112的最大深度H不变。
所述流道112的最大径宽连续线性减小、连续非线性减小或阶梯型减小。
在一个实施例中，所述流道112的侧壁或底面为弧形。沿所述输送方向A，所述流道112的截面形状不变，所述流道112的最大深度H逐渐减小，所述流道112的最大径宽不变。所述流道112的最大深度H连续线性减小、连续非线性减小或阶梯型减小。
在一个实施例中，沿所述流道112的长度方向上，部分所述流道112的截面面积逐渐减小。所述流道112包括入口处、中部和出口处。
在一个实施例中，沿所述输送方向A，仅所述入口处的部分所述流道112的截面面积逐渐减小，所述中部和所述出口处的部分所述流道112的截面面积不变。所述入口处的部分所述流道112的截面面积逐渐减小的形式可以参照上文中提到的截面面积减小方式。
在一个实施例中，沿所述输送方向A，仅所述中部的部分所述流道112的截面面积逐渐减小，所述入口处和所述出口处的部分所述流道112的截面面积不变。所述中部的部分所述流道112的截面面积逐渐减小可以参照上文中提到的截面面积减小方式。
在一个实施例中，沿所述输送方向A，仅所述出口处的部分所述流道112的截面面积逐渐减小，所述入口处和所述中部的部分所述流道112的截面面积不变。所述出口处的部分所述流道112的截面面积逐渐减小可以参照上文中提到的截面面积减小方式。
在一个实施例中，沿所述反应气体的输送方向A，所述流道112的截面形状可以是变化的，只要保证所述流道112的截面面积逐渐减小即可。
请参见图32，本公开实施例提供一种燃料电池双极板10包括基板100。所述基板100包括第一表面110。所述第一表面110开设第三流道单元200。所述第三流道单元200包括多条并列排布的第三流道210。相邻两条所述第三流道210之间形成第一脊220。多条所述第三流道210用于沿第一方向a输送反应气体。所述第三流道210的截面形状为矩形。沿所述第一方向a，多条所述第一脊220的宽度W相等，所述第三流道210截面的宽度W逐渐减小，所述第三流道210截面的深度H不变。
本公开实施例提供的所述燃料电池双极板10。所述第三流道210中反应气体的流量一定。沿所述第一方向a，多条所述第一脊220的宽度W相等，所述第三流道210截面的宽度W逐渐减小，所述第三流道210截面的深度H不变。所述第三流道210截面面积逐渐变小，所述反应气体流速逐渐增大，所述第三流道210的排水速率逐渐增大。所述燃料电池双极板10使得所述第三流道210各位置的排水速率与液态水量相匹配，有效避免局部膜干和局部水淹。所述燃料电池双极板10保证气体扩散层内不发生积水的同时质子交换膜不会过干，燃料电池内部极化损失降低，提高了燃料电池的性能。
在一个实施例中，所述第一表面110还开设第四流道单元300。所述第四流道单元300包括多条并列排布的第四流道310。相邻两条所述第四流道310之间形成第二脊320。多条所述第四流道310用于沿第二方向b输送反应气体。所述第二方向b与所述第一方向a相反。所述第四流道310的截面形状为矩形。沿所述第二方向b，多条所述第二脊320的宽度W相等，所述第四流道310截面的宽度W逐渐减小，所述第四流道310截面的深度H不变。
所述第三流道单元200与所述第四流道单元300中心对称分布，提高了所述基板100的利用率，便于减小所述燃料电池的体积。
在一个实施例中，所述第三流道单元200和所述第四流道单元300设置于所述第一表面110的中部。所述燃料电池双极板10还包括第一歧管组和第二歧管组。所述第一歧管组和所述第二歧管组分别包括一个第一反应物进气歧管610、一个第一反应物排气歧管620、一个第二反应物排气歧管630、一个第二反应物进气歧管640和一个冷却水进歧管650。所述第一歧管组和所述第二歧管组中心对称设置于所述基板100的两侧。
在所述第一歧管组中，所述第一反应物进气歧管610、所述第二反应物排气歧管630、所述冷却水进歧管650、所述第一反应物排气歧管620和一个第二反应物进气歧管640顺次排布。所述第一反应物进气歧管610与所述第三流道单元200的进气口连通。所述第一反应物排气歧管620与所述第四流道单元300的排气口连通。
在所述第一歧管组中，一个第二反应物进气歧管640、所述第一反应物排气歧管620、所述冷却水进歧管650、所述第二反应物排气歧管630和所述第一反应物进气歧管610顺次排布。所述第一反应物进气歧管610与所述第四流道单元300的进气口连通。所述第一反应物排气歧管620与所述第三流道单元200的拍气口连通。
在上述实施例中，所述第三流道210与所述第四流道310的截面形状相同，大小相同。所述第三流道210与所述第四流道310的截面形状可以是四边形、六边形或八边形等多边形结构。
所述第三流道210与所述第四流道310的截面形状可以不同，大小可以不同。
请参见图33和图34，本公开实施例提供一种燃料电池双极板10包括第一基板400。所述第一基板400包括相对设置的第一表面110和第二表面140。所述第一表面110开设第三流道单元200。所述第三流道单元200包括多条并列排布的第三流道210。所述第三流道210用于沿第一方向a输送反应气体。所述第三流道210的截面形状为矩形。沿所述第一方向a，所述第三流道210的截面形状不变，所述第三流道210截面的宽度W不变，所述第三流道210截面的深度逐渐减小，所述第三流道210的底面与所述第二表面140之间的厚度T不变，以保证所述燃料电池双极板10的强度。
本公开实施例提供的所述燃料电池双极板10。所述第三流道210中反应气体的流量一定。沿所述第一方向a，所述第三流道210的截面形状不变，所述第三流道210截面的宽度W不变，所述第三流道210的底面与所述第二表面140之间的厚度不变。所述第三流道210截面面积逐渐变小，所述反应气体流速逐渐增大，所述第三流道210的排水速率逐渐增大。所述燃料电池双极板10使得所述第三流道210各位置的排水速率与液态水量相匹配，有效避免局部膜干和局部水淹。所述燃料电池双极板10保证气体扩散层内不发生积水的同时质子交换膜不会过干，燃料电池内部极化损失降低，提高了燃料电池的性能。
在一个实施例中，所述燃料电池双极板10还包括第二基板500。所述第二基板500包括相对设置的第三表面510和第四表面520。所述第四表面520与所述第二表面140贴合。所述第三表面510开设第四流道单元300。所述第四流道单元300包括多条并列排布的第四流道310。所述第四流道310用于沿第二方向b输送反应气体。所述第二方向b与所述第一方向a相反。所述第四流道310的截面形状为矩形。沿所述第二方向b，所述第四流道310截面的深度H逐渐减小，所述第四流道310截面的宽度W不变，所述第四流道310的底面与所述第四表面520之间的厚度T不变。
所述第三流道210截面的宽度W不变，所述第三流道210的底面与所述第二表面140之间的厚度T不变。沿所述第一方向a，所述第一基板400的整体厚度变小。所述第四流道310截面的宽度W不变，所述第三表面510的底面与所述第四表面120之间的厚度T不变。沿所述第二方向b，所述第二基板500的整体厚度变小。
所述第二基板500与所述第一基板400背对背设置，且内部反应物的流向相反。所述第二基板500的厚度较厚的部位对应于所述第一基板400的厚度较薄的部位设置，所述第 二基板500的厚度较薄的部位对应于所述第一基板400的厚度较厚的部位设置，减小了所述燃料电池双极板10的整体厚度，便于减小所述燃料电池的体积。
在上述实施例中，所述第三流道210与所述第四流道310的截面形状相同，大小相同。所述第三流道210与所述第四流道310的截面形状可以是四边形、六边形或八边形等多边形结构。
所述第三流道210与所述第四流道310的截面形状可以不同，大小可以不同。
请一并参见图35，在一个实施例中，所述第三流道210截面的深度H逐渐减小，所述第三流道210截面的宽度W逐渐减小，所述第三流道210的底面与所述第二表面420之间的厚度T不变。所述第四流道310截面的深度H逐渐减小，所述第四流道310截面的宽度W不变，所述第四流道310的底面与所述第四表面520之间的厚度T不变。
请一并参见图36，本公开实施例提供一种燃料电池双极板10的加工方法。所述加工方法包括：首先，通过模压或机加工加工出矩形截面的流道，再使用超快激光加工脊部侧面或流道底面，由于激光加工非常灵活、功率连续可调且加工过程中不产生机械应力，因此去除的材料的形状可以多种多样，进而加工出多种非矩形截面流道以及截面积以多种形式变化的流道。
以上所述实施例的各技术特征可以进行任意的组合，为使描述简洁，未对上述实施例中的各个技术特征所有可能的组合都进行描述，然而，只要这些技术特征的组合不存在矛盾，都应当认为是本说明书记载的范围。
以上所述实施例仅表达了本公开的几种实施方式，但并不能因此而理解为对本公开专利范围的限制。应当指出的是，对于本领域的普通技术人员来说，在不脱离本公开构思的前提下，还可以做出若干变形和改进，这些都属于本公开的保护范围。因此，本公开专利的保护范围应以所附权利要求为准。

Claims (35)

  1. 一种燃料电池双极板加工方法，其特征在于，包括：
    获取石墨双极板毛坯；
    根据目标流道结构图(30)，绘制整体加工路径图(40)；
    根据所述整体加工路径图(40)，利用激光在所述石墨双极板毛坯表面加工流道，得到成型石墨双极板；
    对所述成型石墨双极板进行表面洁净处理和表面疏水处理。
  2. 如权利要求1所述的燃料电池双极板加工方法，其特征在于，加工石墨双极板毛坯的步骤包括：
    加工形成硬质双极板原始毛坯；
    采用机械加工机床在所述硬质双极板原始毛坯表面开设进出口和公共流道气孔，以形成石墨双极板毛坯。
  3. 如权利要求1所述的燃料电池双极板加工方法，其特征在于，根据目标流道结构图(30)，绘制整体加工路径图(40)的步骤包括：
    根据所述目标流道结构图(30)，获取目标流道(300)的流道宽度、流道深度、流道延伸形状和流道间距；
    根据所述流道宽度选取激光的光斑直径和走光间距；
    根据所述流道深度选取扫描频率、走光速度和扫描次数；
    根据所述流道延伸形状、所述流道间距、所述光斑直径和所述走光间距，得到所述整体加工路径图(40)。
  4. 如权利要求3所述的燃料电池双极板加工方法，其特征在于，根据所述流道延伸形状、所述流道间距、所述光斑直径和所述走光间距，得到所述整体加工路径图(40)的步骤包括：
    所述目标流道结构图(30)包括多条目标流道(300)，所述整体加工路径图(40)包含多个扫描线组(400)，所述多个扫描线组(400)与所述多条目标流道(300)一一对应设置，每个所述扫描线组(400)包含多条扫描线，根据所述流道延伸形状，得到与所述目标流道(300)对应的所述扫描线的形状；
    根据所述光斑直径和所述走光间距计算每条所述目标流道(300)的走光次数，根据所述走光次数得到所述扫描线的条数，根据所述走光间距得到对应的相邻两条所述扫描线的扫描线间距，相邻两条所述扫描线位于一个所述扫描线组(400)；
    根据所述流道间距得到对应的相邻两个所述扫描线组(400)的扫描组间距；
    根据所述扫描线的形状、所述扫描线的条数、所述扫描线间距和所述扫描组间距，得到所述整体加工路径图(40)。
  5. 如权利要求3所述的燃料电池双极板加工方法，其特征在于，在根据所述流道深度选取扫描频率、走光速度和扫描次数的步骤之前，所述加工方法还包括：
    进行预扫描实验，以确定所述扫描频率、所述走光速度和所述加工扫描次数。
  6. 如权利要求5所述的燃料电池双极板加工方法，其特征在于，进行预扫描实验，以确定所述扫描频率、所述走光速度和所述加工扫描次数的步骤包括：
    获取实验石墨双极板毛坯，所述实验石墨双极板毛坯与待加工的所述石墨双极板毛坯相同；
    采用所述扫描频率和所述走光速度对所述实验石墨双极板毛坯进行第一次直线扫描，第一次实验扫描次数为N，得到第一凹槽，测量所述第一凹槽的深度，并得到第一深度；
    采用所述扫描频率和所述走光速度对所述实验石墨双极板毛坯进行第二次直线扫描，第二次实验扫描次数为M，得到第二凹槽，测量所述第二凹槽的深度，并得到第二深度，其中M大于N，其中M和N为正整数；
    根据所述第一深度、所述第二深度、M、N和所述流道深度，确定所述加工扫描次数。
  7. 如权利要求6所述的燃料电池双极板加工方法，其特征在于，根据所述第一深度、所述第二深度、M、N和所述流道深度，采用差分法确定所述加工扫描次数。
  8. 如权利要求1所述的燃料电池双极板加工方法，其特征在于，根据所述整体加工路径图(40)，采用高能激光器在所述石墨双极板毛坯表面加工流道，得到成型石墨双极板。
  9. 如权利要求4所述的燃料电池双极板加工方法，其特征在于，根据所述目标流道(300)的延伸形状，得到对所述目标流道(300)对应的所述扫描线的形状的步骤还包括：
    判断所述目标流道(300)中是否包含拐角结构；
    若是，则与所述拐角结构对应的所述扫描线为弧形倒角结构(402)。
  10. 如权利要求4所述的燃料电池双极板加工方法，其特征在于，所述多条目标流道(300)包括第一目标流道(310)和第二目标流道(320)，所述多个扫描线组(400)包含第一扫描线组(410)和第二扫描线组(420)，所述第一扫描线组(410)包含多个第一扫描线(411)，所述第一扫描线(411)与所述第一目标流道(310)对应，所述第二扫描线组(420)包含多个第二扫描线(421)，所述第二扫描线(421)与所述第二目标流道(320)对应，根据所述目标流道(300)的延伸形状，得到对所述目标流道(300)对应的所述扫描线的形状的步骤还包括：
    判断所述第一目标流道(310)起点是否与所述第二目标流道(320)的延伸路径重叠；
    若是，所述第一扫描线(411)起点设置加工余量间隙。
  11. 如权利要求1所述的燃料电池双极板加工方法，其特征在于，加工石墨双极板毛坯的步骤包括：
    采用石墨粉模压形成所述石墨双极板毛坯，所述石墨双极板毛坯表面已开设进出口、公共流道气孔和主流道。
  12. 一种燃料电池双极板，其特征在于，包括：
    基板(100)，所述基板(100)的表面开设相邻的第一流道(102)和第二流道(103)，所述第一流道(102)和所述第二流道(103)之间形成脊(104)，在所述脊(104)的顶面开设凹槽(105)，且所述第一流道(102)或所述第二流道(103)中的一个或两个流道与所述凹槽(105)连通。
  13. 如权利要求12所述的燃料电池双极板，其特征在于，所述第一流道(102)和所述第二流道(103)用于沿第一方向输送相同的反应气体，所述凹槽(105)沿第二方向延伸，所述第二方向与所述第一方向之间的夹角为锐角。
  14. 如权利要求13所述的燃料电池双极板，其特征在于，在所述脊(104)的底面开设多个所述凹槽(105)，沿所述第一方向，多个所述凹槽(105)间隔排布。
  15. 如权利要求14所述的燃料电池双极板，其特征在于，沿所述第一方向，相邻两个所述凹槽(105)之间的间距逐渐减小。
  16. 如权利要求12-15中任意一项所述的燃料电池双极板，其特征在于，所述凹槽(105)的底部开设第一孔(70)，且所述第一孔(70)与所述第一流道(102)连通。
  17. 如权利要求16所述的燃料电池双极板，其特征在于，所述第一孔(70)包括相交的第一孔道(710)和第二孔道(710)，所述第一孔道(710)与所述第一流道(102)连通，所述第二孔道(710)与所述第二流道(103)连通。
  18. 一种燃料电池双极板，其特征在于，包括：
    基板(100)，所述基板(100)的表面开设相邻的第一流道(102)和第二流道(103)，所述第一流道(102)和所述第二流道(103)之间形成脊(104)，在所述脊(104)的顶面开设第二孔(80)，且所述第二孔(80)与所述第一流道(102)连通。
  19. 如权利要求18所述的燃料电池双极板，其特征在于，所述第二孔(80)包括相交的第三孔道(810)和第四孔道(820)，所述第三孔道(810)与所述第一流道(102)连通，所述第四孔道(820)与所述第二流道(103)连通。
  20. 如权利要求19所述的燃料电池双极板，其特征在于，在所述脊(104)的顶面开设多个所述第二孔(80)，沿所述第一方向，多个所述第二孔(80)间隔排布。
  21. 如权利要求20所述的燃料电池双极板，其特征在于，沿所述第一方向，相邻两个所述第二孔(80)之间的间距逐渐减小。
  22. 一种如权利要求17-21中任意一项所述的燃料电池双极板的加工方法，其特征在于，采用激光雕刻法加工所述燃料电池双极板。
  23. 一种燃料电池双极板，其特征在于，包括：
    基板(100)，所述基板(100)包括第一表面(110)，所述第一表面(110)开设流道(112)，所述流道(112)用于输送反应气体，沿着所述反应气体在所述流道(112)的输送方向，所述流道(112)的截面面积逐渐减小。
  24. 如权利要求23所述的燃料电池双极板，其特征在于，沿所述反应气体的输送方向，所述流道(112)的截面面积连续型逐渐减小。
  25. 如权利要求24所述的燃料电池双极板，其特征在于，沿所述反应气体的输送方向，所述流道(112)的截面面积连续非线性逐渐减小。
  26. 如权利要求23所述的燃料电池双极板，其特征在于，沿所述反应气体的输送方向，所述流道(112)的截面面积阶梯型逐渐减小。
  27. 如权利要求23所述的燃料电池双极板，其特征在于，所述流道(112)的截面形状为四边形、六边形或八边形。
  28. 如权利要求23所述的燃料电池双极板，其特征在于，所述流道(112)的侧壁为弧形。
  29. 如权利要求23所述的燃料电池双极板，其特征在于，所述流道(112)的截面形状为矩形，沿所述输送方向，所述流道(112)截面的宽度逐渐减小，所述流道(112)截面的深度不变。
  30. 如权利要求23所述的燃料电池双极板，其特征在于，所述流道(112)的截面形状为矩形，沿所述输送方向，所述流道(112)截面的深度逐渐减小，所述流道(112)截面的宽度不变。
  31. 如权利要求23所述的燃料电池双极板，其特征在于，所述流道(112)的截面形状为矩形，沿所述输送方向，所述流道(112)截面的深度逐渐减小，所述流道(112)截面的宽度逐渐减小。
  32. 一种燃料电池双极板，其特征在于，包括：
    基板(100)，所述基板(100)包括第一表面(110)，所述第一表面(110)开设第三流道单元(200)，所述第三流道单元(200)包括多条并列排布的第三流道(210)，相邻两条所述第三流道(210)之间形成第一脊(220)，多条所述第三流道(210)用于沿第一方向输送反应气体，所述第三流道(210)的截面形状为矩形，沿所述第一方向，多条所述第一脊(220)的宽度相等，所述第三流道(210)截面的宽度逐渐减小，所述第三流道(210)截面的深度不变。
  33. 如权利要求32所述的燃料电池双极板，其特征在于，所述第一表面(110)还开设第四流道单元(300)，所述第四流道单元(300)包括多条并列排布的第四流道(310)，相邻两条所述第四流道(310)之间形成第二脊(320)，多条所述第四流道(310)用于沿第二方向输送反应气体，所述第二方向与所述第一方向相反，所述第四流道(310)的截面形状为矩形，沿所述第二方向，多条所述第二脊(320)的宽度相等，所述第四流道(310)截面的宽度逐渐减小，所述第四流道(310)截面的深度不变。
  34. 一种燃料电池双极板，其特征在于，包括：
    第一基板(400)，所述第一基板(400)包括相对设置的第一表面(110)和第二表面(140)，所述第一表面(110)开设第三流道单元(200)，所述第三流道单元(200)包括多条并列排布的第三流道(210)，所述第三流道(210)用于沿第一方向输送反应气体， 所述第三流道(210)的截面形状为矩形，沿所述第一方向，所述第三流道(210)的截面形状不变，所述第三流道(210)截面的深度逐渐减小，所述第三流道(210)截面的宽度不变，所述第三流道(210)的底面与所述第二表面(140)之间的厚度不变。
  35. 如权利要求34所述的燃料电池双极板，其特征在于，还包括：
    第二基板(500)，所述第二基板(500)包括相对设置的第三表面(510)和第四表面(520)，所述第四表面(520)与所述第二表面(120)贴合，所述第三表面(510)开设第四流道单元(300)，所述第四流道单元(300)包括多条并列排布的第四流道(310)，所述第四流道(310)用于沿第二方向输送反应气体，所述第二方向与所述第一方向相反，所述第四流道(310)的截面形状为矩形，沿所述第二方向，所述第四流道(310)截面的深度逐渐减小，所述第四流道(310)截面的宽度不变，所述第四流道(310)的底面与所述第四表面(520)之间的厚度不变。
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