WO2019128073A1 - Method for preparing efficient mwt solar cell - Google Patents

Method for preparing efficient mwt solar cell Download PDF

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WO2019128073A1
WO2019128073A1 PCT/CN2018/088321 CN2018088321W WO2019128073A1 WO 2019128073 A1 WO2019128073 A1 WO 2019128073A1 CN 2018088321 W CN2018088321 W CN 2018088321W WO 2019128073 A1 WO2019128073 A1 WO 2019128073A1
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preparing
silicon wafer
electrode
diffusion
passivation layer
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PCT/CN2018/088321
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French (fr)
Chinese (zh)
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李质磊
安欣睿
逯好峰
吴仕梁
路忠林
盛雯婷
张凤鸣
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江苏日托光伏科技股份有限公司
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/18—Processes or apparatus specially adapted for the manufacture or treatment of these devices or of parts thereof
    • H01L31/1804—Processes or apparatus specially adapted for the manufacture or treatment of these devices or of parts thereof comprising only elements of Group IV of the Periodic System
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/02—Details
    • H01L31/0224—Electrodes
    • H01L31/022408—Electrodes for devices characterised by at least one potential jump barrier or surface barrier
    • H01L31/022425—Electrodes for devices characterised by at least one potential jump barrier or surface barrier for solar 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
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/50—Photovoltaic [PV] energy
    • Y02E10/547—Monocrystalline silicon PV 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

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  • the invention relates to the technical field of silicon solar cells, in particular to a method for preparing a high-efficiency MWT solar cell.
  • Metal perforated wound silicon solar cells are receiving more and more attention due to their high efficiency, small shading area and better appearance.
  • MWT silicon solar cells use laser drilling to transfer the energy collected from the front side to the back of the battery to reduce the shading area to improve conversion efficiency.
  • Patent CN201410016190.6 provides a low-cost preparation method for MWT.
  • the modification method adds only two processes in the production process of the conventional crystalline silicon battery, that is, adding a laser drilling process before the texturing process and after diffusion or Add a hole to the insulation after the coating. Because the method is simple in process and less in equipment, it is the only mass production process for MWT battery production in the industry.
  • PERC Local contact back passivation
  • solar cells are a highly efficient solar cell technology newly developed in the last two years and have received extensive attention in the industry.
  • the patent CN201410484916.9 provides a technique for preparing a passivation layer by screen printing nano-alumina or silicon oxide
  • the patent CN201710054179.2 provides a low-complexity single-crystal PERC battery process scheme
  • the patent CN201710125141.X provides A process scheme for a P-type PERC double-sided solar cell.
  • the core of the PERC battery process technology is to cover the back surface of the silicon wafer with aluminum oxide or silicon oxide film to passivate the surface to improve the long-wave response, thereby improving the conversion efficiency of the battery.
  • a layer of silicon nitride film is generally coated on the aluminum oxide or silicon oxide film to protect the film. Since alumina or silicon oxide is not electrically conductive, it needs to be partially opened to form an ohmic contact, collecting current.
  • the core of the selective emitter (Selective Emitter SE) battery technology is to heavily dope the contact area between the cell and the gate electrode, reducing the silver-silicon contact resistance, thereby improving the fill factor; the area between the cell gate line electrodes Light doping increases short-wavelength light response and reduces surface recombination, thereby increasing open circuit voltage and short-circuit current. Since this structure takes into account both the open circuit voltage, the short circuit current, and the fill factor, the photoelectric conversion efficiency of the battery can be effectively improved.
  • the technical route for preparing SE batteries is many and mature, including laser doping, secondary diffusion, silicon ink, and the like.
  • the present invention provides a method for preparing a high-efficiency MWT solar cell, which has high conversion efficiency, low investment in process equipment, low cost, and is suitable for mass production.
  • the method for preparing a high-efficiency MWT solar cell according to the present invention comprises: performing a etching process after the flock-spreading silicon wafer is subjected to a masking process, and performing the following processes in sequence after the etching process is completed:
  • (b) front anti-reflection film preparing a layer of anti-reflection film on the front side of the cell sheet;
  • (c) back protective film a protective film is coated on the passivation layer on the back side of the battery sheet;
  • the masking process includes preparing a mask pattern corresponding to the positive electrode pattern on the diffusion surface of the silicon wafer; the etching step includes removing the PN junction around the silicon wafer and the back surface, and depositing the front diffusion layer outside the mask pattern to remove the mask.
  • the slurry is removed from the phosphosilicate glass and backside polished.
  • the slurry used for the mask is a paraffin or acid-resistant polymer material having a thickness of 5 to 30 ⁇ m.
  • the mask slurry is removed using a base or diethylene glycol monobutyl ether.
  • the square resistance after the throwing is controlled to be 90-150 ⁇ / ⁇ , and further 95-105 ⁇ / ⁇ .
  • the passivation layer is aluminum oxide or silicon oxide, and the passivation layer has a thickness of 1 to 50 nm and further 2 to 10 nm.
  • the anti-reflection film is silicon nitride, having a refractive index of 1.9-2.2, further 2-2.1, a film thickness of 60-100 nm, further 80-90 nm; the protective film is silicon nitride, and the refractive index is 1.9-2.2. Further, it is 2-2.1, and the film thickness is 10-150 nm, further 110-125 nm.
  • the silicon wafer is perforated before being subjected to texturing diffusion, and a hole for filling the slurry to charge the front electrode to the back surface of the substrate is formed on the silicon wafer; A mask layer is prepared in the hole.
  • Specific preparation steps include:
  • preparation of the back electrode preparing the positive electrode of the back surface electrode of the MWT and the negative electrode of the back electrode on the back side of the battery piece; and blocking the hole;
  • Aluminum back field preparation preparing an aluminum back field on the back side of the battery sheet
  • Front electrode preparation preparing a front electrode on the front side of the battery sheet
  • the method for preparing the high-efficiency MWT solar cell includes:
  • preparation of the back electrode preparing the anode of the back electrode of the MWT on the back side of the silicon wafer;
  • Front electrode preparation preparing a front electrode on the front side of the battery sheet
  • the silicon wafer is spread on one side in a back-to-back manner, and the diffusion source is POCl 3 , and the diffusion square resistance is 30-100 ⁇ / ⁇ , and further 50-60 ⁇ / ⁇ .
  • the conductive paste may specifically be Heraeus SOL570.
  • the MWT is simultaneously superimposed with the SE and PERC process technologies.
  • the front side printing or printing mask slurry is used to prepare the mask layer on the front side and the hole of the battery while achieving SE.
  • the purpose of the MWT insulation the prepared battery has high conversion efficiency, less investment in the process route equipment, low cost, and is suitable for mass production.
  • Figure 1 is a laser perforation pattern of a MWT solar cell
  • Figure 2 is a front mask pattern
  • Figure 3 is another front mask pattern
  • Figure 4 is a rear electrode pattern of the MWT solar cell
  • Figure 5 is an aluminum back field of a MWT solar cell
  • Figure 6 is a front electrode pattern of the MWT solar cell
  • Figure 7 is a back electrode pattern of the MWT solar cell
  • Figure 8 is a negative electrode pattern of the back electrode of the MWT solar cell
  • FIG. 9 is a schematic structural view of a MWT solar cell.
  • FIG. 9 shows the structure of a high-efficiency MWT solar cell comprising a front side (ie, a light-receiving surface) of a silicon wafer 1 having a diffusion layer 2, an anti-reflection film 3 overlying the diffusion layer 2, and a front gate provided on the anti-reflection film 3.
  • a wire electrode (or positive electrode) 4 a passivation layer 5 disposed on the back surface of the silicon wafer, a protective film 6 overlying the passivation layer 5, and an electrode hole 7 penetrating the diffusion layer, the silicon wafer, the anti-reflection film, and the passivation layer
  • the protective film and the aluminum back field are filled with a conductive paste to connect the electrode hole with the positive electrode to form a negative electrode 8 of the back electrode, and the negative electrode 8 has a 6 ⁇ 6 matrix distribution, and the back surface of the silicon plate is provided with a passivation layer and a protective film.
  • the positive electrode 9 of the back electrode has a 5 ⁇ 5 matrix distribution, the positive electrode of each row is between two rows of negative electrodes, the passivation layer and the protective film are formed with a slit 10, and the aluminum back field 11 is covered on the back protective film, and the back surface is avoided. electrode.
  • Wafer using solar grade P-type single crystal or polycrystalline silicon wafer as the substrate;
  • Laser drilling According to the dot pattern of the MWT hole in Fig. 1, the laser is used to open a hole in the cell sheet, and the hole is circular and has a diameter of 0.12 mm.
  • Texturing cleaning and texturing are carried out by conventional chemical cleaning and texturing methods to remove the damaged layer on the surface of the silicon wafer and reduce the recombination rate of the photo-generated carriers. At the same time, the surface of the silicon wafer is made into a suede to reduce the reflectivity. .
  • Diffusion using a POCl 3 diffusion source for high temperature (temperature 840 ° C) back-to-back single-sided diffusion, diffusion resistance is controlled at 60 ⁇ / ⁇ ;
  • a mask pattern of a pattern (corresponding to a positive electrode pattern) as shown in Fig. 2 was prepared on the diffusion surface by printing while a mask layer was prepared in the hole.
  • the masking paste used is a paraffin or acid-resistant polymer material having a film thickness of 5 to 30 ⁇ m.
  • Etching The PN junction on the periphery and the back of the silicon wafer after diffusion is removed by conventional chemical method; the front diffusion layer outside the mask pattern is thrown by conventional chemical method, and the square resistance after the junction is controlled at 105 ⁇ / ⁇ ; The alkali removes the mask slurry in the front side and the hole; removes the phosphosilicate glass, and performs backside polishing;
  • Back passivation layer preparation a 3 nm thick Al 2 O 3 passivation film is deposited on the back side of the cell by chemical vapor deposition (CVD);
  • Front side anti-reflection film a silicon nitride anti-reflection film having a refractive index of 2.06 and a film thickness of 85 nm is prepared by a PECVD apparatus;
  • Back protective film a silicon nitride anti-reflection film having a refractive index of 2.10 and a film thickness of 120 nm is prepared by a PECVD apparatus;
  • Laser grooving use a laser to sag the aluminum oxide and silicon nitride protective film on the back side;
  • the back electrode by screen printing, the positive electrode of the back electrode of the MWT and the negative electrode of the back electrode are prepared on the back side of the cell sheet, and the hole is blocked, as shown in FIG. 4;
  • Aluminum back field preparation The aluminum back field shown in Fig. 5 is prepared on the back side of the battery sheet by screen printing, and the positive electrode, the negative electrode and the laser perforated hole on the back surface of the MWT battery are avoided during printing;
  • Front electrode A front electrode as shown in Fig. 6 was prepared on the front side of the MWT cell by screen printing.
  • Wafer using solar grade P-type single crystal or polycrystalline silicon wafer as the substrate;
  • Laser drilling According to the dot pattern of the MWT hole in Fig. 1, the laser is used to open a hole in the cell sheet, and the hole is circular and has a diameter of 0.12 mm.
  • Texturing cleaning and texturing are carried out by conventional chemical cleaning and texturing methods to remove the damaged layer on the surface of the silicon wafer and reduce the recombination rate of the photo-generated carriers. At the same time, the surface of the silicon wafer is made into a suede to reduce the reflectivity. ;
  • Diffusion using a POCl 3 diffusion source for high temperature (temperature 840 ° C) back-to-back single-sided diffusion, diffusion resistance is controlled at 50 ⁇ / ⁇ ;
  • a mask pattern of a pattern (corresponding to a positive electrode pattern, no main gate line) as shown in FIG. 3 was prepared on the diffusion surface by printing, and a mask layer was prepared in the hole.
  • the masking paste used was a paraffin wax or an acid-resistant polymer material having a film thickness of 5 to 30 ⁇ m.
  • Etching The PN junction around the diffusion and the back surface of the silicon wafer is removed by conventional chemical method; the front diffusion layer outside the mask pattern is thrown by conventional chemical method, and the square resistance after the junction is controlled at 95 ⁇ / ⁇ ; The alkali removes the mask slurry in the front side and the hole; removes the phosphosilicate glass, and performs backside polishing;
  • Back passivation layer preparation a 2 nm thick Al 2 O 3 passivation film is deposited on the back side of the cell by chemical vapor deposition (CVD);
  • Frontal anti-reflection film a silicon nitride anti-reflection film having a refractive index of 2.06 and a film thickness of 88 nm is prepared by a PECVD apparatus;
  • Back protective film a silicon nitride anti-reflection film having a refractive index of 2.08 and a film thickness of 120 nm is prepared by a PECVD apparatus;
  • Laser grooving use a laser to sag the aluminum oxide and silicon nitride protective film on the back side;
  • the back electrode by screen printing, the positive electrode of the back electrode of the MWT and the negative electrode of the back electrode are prepared on the back side of the cell sheet, and the hole is blocked, as shown in FIG. 4;
  • Aluminum back field preparation The aluminum back field shown in Fig. 5 was prepared on the back side of the battery sheet by screen printing, and the positive electrode, the negative electrode and the laser perforated hole on the back of the MWT battery were avoided during printing.
  • Front electrode A front electrode as shown in Fig. 6 was prepared on the front side of the MWT cell by screen printing.
  • Wafer using solar grade P-type single crystal or polycrystalline silicon wafer as the substrate;
  • Texturing cleaning and texturing are carried out by conventional chemical cleaning and texturing methods to remove the damaged layer on the surface of the silicon wafer and reduce the recombination rate of the photo-generated carriers. At the same time, the surface of the silicon wafer is made into a suede to reduce the reflectivity. .
  • Diffusion using a POCl 3 diffusion source for high temperature (temperature 840 ° C) back-to-back single-sided diffusion, diffusion resistance is controlled at 50 ⁇ / ⁇ ;
  • a mask pattern of a pattern (corresponding to a positive electrode pattern, without a main gate line) as shown in FIG. 3 was prepared on the diffusion surface by printing.
  • the masking paste used was a paraffin wax or an acid-resistant polymer material having a film thickness of 5 to 30 ⁇ m.
  • Etching The PN junction on the periphery and the back of the silicon wafer after diffusion is removed by conventional chemical method; the front diffusion layer outside the mask pattern is thrown by conventional chemical method, and the square resistance after the junction is controlled at 100 ⁇ / ⁇ ; Alkali removes the masking paste on the front side; removes the phosphorous silicon glass and performs backside polishing;
  • Back passivation layer preparation a 2 nm thick Al 2 O 3 passivation film is deposited on the back side of the cell by chemical vapor deposition (CVD);
  • Front side anti-reflection film a silicon nitride anti-reflection film having a refractive index of 2.02 and a film thickness of 80 nm is prepared by a PECVD apparatus;
  • a silicon nitride anti-reflection film having a refractive index of 2.08 and a film thickness of 120 nm is prepared by a PECVD apparatus;
  • Laser grooving use a laser to sag the aluminum oxide and silicon nitride protective film on the back side;
  • the positive electrode of the back electrode of the MWT is prepared on the back side of the cell sheet by screen printing, as shown in FIG. 7;
  • Aluminum back field preparation The aluminum back field shown in Fig. 5 was prepared on the back side of the battery sheet by screen printing, and the positive electrode, the negative electrode and the laser perforated hole on the back side of the MWT battery were avoided during printing.
  • Front electrode A front electrode as shown in Fig. 6 was prepared on the front side of the MWT cell by screen printing.
  • the cell sheet is patterned according to the MWT hole pattern of Fig. 1, and the laser is used to make holes in the cell sheet.
  • the hole is circular and has a diameter of 0.12 mm.
  • Printing conductive adhesive in the hole area of the laser opening, printing conductive adhesive (specifically, Heraeus SOL570) to form the negative electrode of the back electrode, plugging the hole and connecting with the front electrode pattern to form a current path, as shown in Figure 8. Display pattern
  • Drying Drying and curing the conductive adhesive with a temperature of 50°-200°.
  • Example 3 The lower the punching process, the lower the overall chipping rate.
  • the chipping rate of Example 1-2 was reduced by 0.5%, and the conductive paste method (Example 3) was compared with the conventional silver paste.
  • the cost of the plugging process (Example 1-2) is reduced, and the grade A product rate can be increased by 0.5% to 1%.
  • FIGS. 1-8 in the above embodiments are patterns in the preparation of existing solar cells, and the present invention is not limited to the above-described patterns, and other graphic designs may be employed.

Abstract

A method for preparing an efficient MWT solar cell, comprising: applying a masking process and then an etching process to a textured and diffused silicon wafer (1), and successively conducting the following processes after the etching process is ended: a back passivation layer (5): preparing a passivation layer on the back of a cell piece; a front anti-reflection film (3): preparing an anti-reflection film on a front face of the cell piece; a back protective film (6): covering a protective film over the back passivation layer of the cell piece; create grooves: creating grooves on the back passivation layer and protective layer, so that aluminum back field slurry and a silicon substrate form ohmic contact, wherein the mask process comprises preparing a mask pattern corresponding to a positive electrode pattern on a diffusion face of the silicon wafer, and the etching process comprises removing PN junctions at the periphery and back of the silicon wafer, performing knot removal on a front diffusion layer (2) outside the mask pattern to remove mask slurry and remove phosphosilicate glass, and performing back polishing. The prepared cell has a high conversion efficiency, the investment for the process line devices is low and the cost is low, and is applicable for large-scale production.

Description

一种高效MWT太阳能电池的制备方法Method for preparing high-efficiency MWT solar cell 技术领域Technical field
本发明涉及硅太阳能电池工艺技术领域，尤其涉及一种高效MWT太阳能电池制备方法。The invention relates to the technical field of silicon solar cells, in particular to a method for preparing a high-efficiency MWT solar cell.
背景技术Background technique
金属穿孔卷绕硅太阳能电池(MWT)因其效率高，遮光面积小以及更好的外观特点受到越来越多的关注。MWT硅太阳能电池是通过激光钻孔将正面收集的能量穿过电池转移至电池背面，以减少遮光面积来达到提高转换效率的目的。专利CN201410016190.6提供了一种MWT的低成本制备方法，改方法在传统晶硅电池的制作流程上仅增加两道工序，即：在制绒工序前增加一道激光打孔工序和在扩散后或镀膜后增加一道孔洞处绝缘的工序。由于该方法工艺简单，增加设备少，成为目前业内MWT电池生产唯一量产的工艺。Metal perforated wound silicon solar cells (MWT) are receiving more and more attention due to their high efficiency, small shading area and better appearance. MWT silicon solar cells use laser drilling to transfer the energy collected from the front side to the back of the battery to reduce the shading area to improve conversion efficiency. Patent CN201410016190.6 provides a low-cost preparation method for MWT. The modification method adds only two processes in the production process of the conventional crystalline silicon battery, that is, adding a laser drilling process before the texturing process and after diffusion or Add a hole to the insulation after the coating. Because the method is simple in process and less in equipment, it is the only mass production process for MWT battery production in the industry.
局部接触背钝化(PERC)太阳能电池是最近两年新开发出来的一种高效太阳能电池技术，得到了业内的广泛关注。如专利CN201410484916.9提供了一种丝网印刷纳米氧化铝或氧化硅制备钝化层的技术；专利CN201710054179.2提供了一种低复合率的单晶PERC电池工艺方案；专利CN201710125141.X提供了一种P型PERC双面太阳能电池的工艺方案。PERC电池工艺技术的核心是在硅片的背光面用氧化铝或氧化硅薄膜覆盖，起到钝化表面提高长波响应，从而提高电池的转换效率。同时，为了避免在烧结过程中铝金属破坏钝化层的钝化效率，一般在氧化铝或氧化硅薄膜上再覆盖一层氮化硅薄膜，起到保护作用。由于氧化铝或氧化硅不导电，需要对其局部开口以便形成欧姆接触，收集电流。Local contact back passivation (PERC) solar cells are a highly efficient solar cell technology newly developed in the last two years and have received extensive attention in the industry. For example, the patent CN201410484916.9 provides a technique for preparing a passivation layer by screen printing nano-alumina or silicon oxide; the patent CN201710054179.2 provides a low-complexity single-crystal PERC battery process scheme; the patent CN201710125141.X provides A process scheme for a P-type PERC double-sided solar cell. The core of the PERC battery process technology is to cover the back surface of the silicon wafer with aluminum oxide or silicon oxide film to passivate the surface to improve the long-wave response, thereby improving the conversion efficiency of the battery. At the same time, in order to avoid the passivation efficiency of the aluminum metal in the sintering process during the sintering process, a layer of silicon nitride film is generally coated on the aluminum oxide or silicon oxide film to protect the film. Since alumina or silicon oxide is not electrically conductive, it needs to be partially opened to form an ohmic contact, collecting current.
选择性发射极(Selective Emitter SE)电池技术的核心是在电池片与栅线电极的接触区进行重掺杂，降低银硅接触电阻，从而改善填充因子；在电池片栅线电极之间的区域进行轻掺杂，提高短波长光线响应和降低表面复合，从而提高开路电压和短路电流。由于此结构同时兼顾了开路电压、短路电流和填充因子，从而能有效提升电池片的光电转换效率。制备SE电池的技术路线很多且成熟，包括激光掺杂法、二次扩散法、硅墨法等等。The core of the selective emitter (Selective Emitter SE) battery technology is to heavily dope the contact area between the cell and the gate electrode, reducing the silver-silicon contact resistance, thereby improving the fill factor; the area between the cell gate line electrodes Light doping increases short-wavelength light response and reduces surface recombination, thereby increasing open circuit voltage and short-circuit current. Since this structure takes into account both the open circuit voltage, the short circuit current, and the fill factor, the photoelectric conversion efficiency of the battery can be effectively improved. The technical route for preparing SE batteries is many and mature, including laser doping, secondary diffusion, silicon ink, and the like.
随着人们对晶硅电池的光电转换效率越来越高的要求，MWT高效电池技术结合其他高效电池技术的技术开发和研究也已迫在眉睫。With the increasing requirements for the photoelectric conversion efficiency of crystalline silicon cells, the development and research of MWT high-efficiency battery technology combined with other high-efficiency battery technologies is also urgent.
发明内容Summary of the invention
发明目的：为解决现有技术中的问题，本发明提供了一种高效MWT太阳能电池的制备方法，所制备的电池转换效率高，工艺路线设备投入少，成本低，适合 规模化量产。OBJECT OF THE INVENTION In order to solve the problems in the prior art, the present invention provides a method for preparing a high-efficiency MWT solar cell, which has high conversion efficiency, low investment in process equipment, low cost, and is suitable for mass production.
技术方案：本发明所述的高效MWT太阳能电池的制备方法，包括：将制绒扩散后的硅片经掩膜工序后再进行刻蚀工序，刻蚀工序结束后依次进行以下工序：Technical Solution: The method for preparing a high-efficiency MWT solar cell according to the present invention comprises: performing a etching process after the flock-spreading silicon wafer is subjected to a masking process, and performing the following processes in sequence after the etching process is completed:
(a)背面钝化层制备：在电池片背面制备一层钝化层；(a) preparation of the back passivation layer: preparing a passivation layer on the back side of the cell sheet;
(b)正面减反膜：在电池片正面制备一层减反膜；(b) front anti-reflection film: preparing a layer of anti-reflection film on the front side of the cell sheet;
(c)背面保护膜：在电池片背面钝化层上覆一层保护膜；(c) back protective film: a protective film is coated on the passivation layer on the back side of the battery sheet;
(d)开槽：将背面的减反膜和保护膜开槽，以便铝背场浆料和硅基体形成欧姆接触；(d) Slotting: grooving the anti-reflection film and the protective film on the back surface so that the aluminum back field paste forms an ohmic contact with the silicon substrate;
其中，掩膜工序包括在硅片扩散面制备正电极图案对应的掩膜图案；刻蚀工序包括去除硅片周边及背面的PN结，对掩膜图形以外正面扩散层进行抛结，去除掩膜浆料，去除磷硅玻璃，并进行背面抛光。The masking process includes preparing a mask pattern corresponding to the positive electrode pattern on the diffusion surface of the silicon wafer; the etching step includes removing the PN junction around the silicon wafer and the back surface, and depositing the front diffusion layer outside the mask pattern to remove the mask. The slurry is removed from the phosphosilicate glass and backside polished.
掩膜所用的浆料为石蜡或抗酸高分子材料，厚度5-30μm。The slurry used for the mask is a paraffin or acid-resistant polymer material having a thickness of 5 to 30 μm.
采用碱或二乙二醇单丁醚去除掩膜浆料。The mask slurry is removed using a base or diethylene glycol monobutyl ether.
所述抛结后的方阻控制在90-150Ω/□，进一步为95-105Ω/□。The square resistance after the throwing is controlled to be 90-150 Ω/□, and further 95-105 Ω/□.
所述钝化层为氧化铝或氧化硅，钝化层的厚度为1-50nm进一步为2-10nm。The passivation layer is aluminum oxide or silicon oxide, and the passivation layer has a thickness of 1 to 50 nm and further 2 to 10 nm.
所述减反膜为氮化硅，折射率为1.9-2.2，进一步为2-2.1，膜厚为60-100nm，进一步为80-90nm；保护膜为氮化硅，折射率为1.9-2.2，进一步为2-2.1，膜厚为10-150nm，进一步为110-125nm。The anti-reflection film is silicon nitride, having a refractive index of 1.9-2.2, further 2-2.1, a film thickness of 60-100 nm, further 80-90 nm; the protective film is silicon nitride, and the refractive index is 1.9-2.2. Further, it is 2-2.1, and the film thickness is 10-150 nm, further 110-125 nm.
其中一种可实施的方式，硅片在经制绒扩散前先进行打孔，在硅片上形成用于填充浆料将正面电极汇集的电流引至基片背面的孔洞；掩膜工序时在孔洞内制备掩膜层。具体制备步骤包括：In one implementation manner, the silicon wafer is perforated before being subjected to texturing diffusion, and a hole for filling the slurry to charge the front electrode to the back surface of the substrate is formed on the silicon wafer; A mask layer is prepared in the hole. Specific preparation steps include:
(1)打孔；(1) punching;
(2)制绒：对硅片进行清洗和织构化，去除硅片表面的损伤层，在硅片表面制成绒面；(2) Texturing: cleaning and texturing the silicon wafer, removing the damaged layer on the surface of the silicon wafer, and forming a suede surface on the surface of the silicon wafer;
(3)扩散：在硅片衬底沉积掺杂源并进行扩散制备PN结；(3) diffusion: depositing a doping source on the silicon substrate and performing diffusion to prepare a PN junction;
(4)掩膜；(4) mask;
(5)刻蚀；(5) etching;
(6)背面钝化层制备；(6) preparation of the back passivation layer;
(7)正面减反膜；(7) positive anti-reflection film;
(8)背面保护膜；(8) back protective film;
(9)开槽；(9) slotting;
(10)背面电极制备：在电池片片背面制备MWT背面电极的正极、背面电极的负极和进行堵孔；(10) preparation of the back electrode: preparing the positive electrode of the back surface electrode of the MWT and the negative electrode of the back electrode on the back side of the battery piece; and blocking the hole;
(11)铝背场制备：在电池片背面制备铝背场；(11) Aluminum back field preparation: preparing an aluminum back field on the back side of the battery sheet;
(12)正面电极制备：在电池片正面制备正面电极；(12) Front electrode preparation: preparing a front electrode on the front side of the battery sheet;
(13)烧结：将电池片共烧形成欧姆接触。(13) Sintering: The battery sheets were co-fired to form an ohmic contact.
另一种可实施的方式，所述高效MWT太阳能电池的制备方法，包括：In another implementation manner, the method for preparing the high-efficiency MWT solar cell includes:
(1)制绒：对硅片进行清洗和织构化，去除硅片表面的损伤层，在硅片表面制成绒面；(1) Texturing: cleaning and texturing the silicon wafer, removing the damaged layer on the surface of the silicon wafer, and forming a suede surface on the surface of the silicon wafer;
(2)扩散：在硅片衬底沉积掺杂源并进行扩散制备PN结；(2) diffusion: depositing a doping source on the silicon substrate and performing diffusion to prepare a PN junction;
(3)掩膜；(3) mask;
(4)刻蚀；(4) etching;
(5)背面钝化层制备；(5) preparation of the back passivation layer;
(6)正面减反膜；(6) positive anti-reflection film;
(7)背面保护膜；(7) a back protective film;
(8)开槽；(8) slotting;
(9)背面电极制备：在硅片背面制备MWT背面电极的正极；(9) preparation of the back electrode: preparing the anode of the back electrode of the MWT on the back side of the silicon wafer;
(10)铝背场制备：在硅片背面制备铝背场；(10) Aluminum back field preparation: preparing an aluminum back field on the back side of the silicon wafer;
(11)正面电极制备：在电池片正面制备正面电极；(11) Front electrode preparation: preparing a front electrode on the front side of the battery sheet;
(12)烧结：将电池片共烧形成欧姆接触；(12) sintering: co-firing the battery sheets to form an ohmic contact;
(13)打孔：在电池片上打孔，形成用于填充浆料将正面电极汇集的电流引至电池片背面的孔洞；(13) Punching: punching a hole in the battery sheet to form a hole for filling the slurry to direct the current collected by the front electrode to the back surface of the battery sheet;
(14)印刷导电胶：用导电胶填充孔洞并制成背面电极的负极，与正面电极相连通形成电流通路；(14) printing conductive adhesive: filling the hole with conductive glue and forming the negative electrode of the back electrode, and connecting with the front electrode to form a current path;
(15)烘干：烘干固化导电胶。(15) Drying: drying and curing the conductive adhesive.
上述方法中，硅片采用背靠背的方式进行单面扩散，扩散源为POCl 3，扩散方阻为30-100Ω/□，进一步为50-60Ω/□。所述导电胶具体可以为贺利氏SOL570。 In the above method, the silicon wafer is spread on one side in a back-to-back manner, and the diffusion source is POCl 3 , and the diffusion square resistance is 30-100 Ω/□, and further 50-60 Ω/□. The conductive paste may specifically be Heraeus SOL570.
与现有技术相比，本发明的有益效果为：Compared with the prior art, the beneficial effects of the present invention are:
1.在传统PERC电池及MWT工艺基础上实现了MWT同时和SE、PERC工艺技术的叠加，采用正面印刷或打印掩膜浆料的方式，在电池正面和孔洞内制备掩膜层，同时达到SE及MWT绝缘的目的，所制备的电池转换效率高，工艺路线设备投入少，成本低，适合规模化量产。1. Based on the traditional PERC battery and MWT process, the MWT is simultaneously superimposed with the SE and PERC process technologies. The front side printing or printing mask slurry is used to prepare the mask layer on the front side and the hole of the battery while achieving SE. And the purpose of the MWT insulation, the prepared battery has high conversion efficiency, less investment in the process route equipment, low cost, and is suitable for mass production.
2.采用导电胶堵孔工艺取代常规银浆堵孔时，可以大大降低了银浆用量，节约了制程成本。2. When the conductive glue plugging process is used to replace the conventional silver paste plugging hole, the amount of silver paste can be greatly reduced, and the process cost is saved.
3.采用激光打孔放在最后工序时，可以显著降低整个制程的碎片率，提高A级品率。3. When laser drilling is placed in the final process, the fragmentation rate of the entire process can be significantly reduced, and the grade A product rate can be improved.
附图说明DRAWINGS
图1为MWT太阳能电池的激光打孔图案；Figure 1 is a laser perforation pattern of a MWT solar cell;
图2为一种正面掩膜图案；Figure 2 is a front mask pattern;
图3为另一种正面掩膜图案；Figure 3 is another front mask pattern;
图4为MWT太阳能电池背面电极图案；Figure 4 is a rear electrode pattern of the MWT solar cell;
图5为MWT太阳能电池的铝背场；Figure 5 is an aluminum back field of a MWT solar cell;
图6为MWT太阳能电池正面电极图案；Figure 6 is a front electrode pattern of the MWT solar cell;
图7为MWT太阳能电池背面电极图案；Figure 7 is a back electrode pattern of the MWT solar cell;
图8为MWT太阳能电池背面电极的负极图案；Figure 8 is a negative electrode pattern of the back electrode of the MWT solar cell;
图9为MWT太阳能电池的结构示意图。9 is a schematic structural view of a MWT solar cell.
具体实施方式Detailed ways
下面结合具体实施例，进一步阐明本发明，应理解这些实施例仅用于说明本发明而不用于限制本发明的范围，在阅读了本发明之后，本领域技术人员对本发明的各种等价形式的修改均落于本申请所附权利要求所限定的范围。The present invention will be further clarified by the following specific examples, which are to be construed as illustrative only and not to limit the scope of the invention. Modifications are within the scope defined by the claims appended hereto.
图9示出了高效MWT太阳能电池的结构，包括正面(即受光面)具有扩散层2的硅片1，覆于扩散层2上的减反膜3，设于减反膜3上的正面栅线电极(或称正电极)4，设于硅片背面的钝化层5，覆于钝化层5上的保护膜6，电极孔7贯穿扩散层、硅片、减反膜、钝化层、保护膜和铝背场，用导电胶填充电极孔与正电极相连通并形成背面电极的负极8，负极8呈6×6矩阵分布，硅片的背面设有贯穿钝化层和保护膜的背面电极的正极9，正极呈5×5矩阵分布，每行正极处于两行负极之间，钝化层和保护膜形成有开槽10，铝背场11覆于背面保护膜上，并避让背面电极。9 shows the structure of a high-efficiency MWT solar cell comprising a front side (ie, a light-receiving surface) of a silicon wafer 1 having a diffusion layer 2, an anti-reflection film 3 overlying the diffusion layer 2, and a front gate provided on the anti-reflection film 3. a wire electrode (or positive electrode) 4, a passivation layer 5 disposed on the back surface of the silicon wafer, a protective film 6 overlying the passivation layer 5, and an electrode hole 7 penetrating the diffusion layer, the silicon wafer, the anti-reflection film, and the passivation layer The protective film and the aluminum back field are filled with a conductive paste to connect the electrode hole with the positive electrode to form a negative electrode 8 of the back electrode, and the negative electrode 8 has a 6×6 matrix distribution, and the back surface of the silicon plate is provided with a passivation layer and a protective film. The positive electrode 9 of the back electrode has a 5×5 matrix distribution, the positive electrode of each row is between two rows of negative electrodes, the passivation layer and the protective film are formed with a slit 10, and the aluminum back field 11 is covered on the back protective film, and the back surface is avoided. electrode.
实施例1Example 1
本实施例高效MWT太阳能电池的制备方法如下：The preparation method of the high efficiency MWT solar cell of this embodiment is as follows:
1.硅片：采用太阳能级P型单晶或多晶硅片作为衬底；1. Wafer: using solar grade P-type single crystal or polycrystalline silicon wafer as the substrate;
2.激光打孔：将电池片按图1的MWT孔洞点阵图形，使用激光器在电池片上开孔，孔洞为圆形，直径为0.12mm。2. Laser drilling: According to the dot pattern of the MWT hole in Fig. 1, the laser is used to open a hole in the cell sheet, and the hole is circular and has a diameter of 0.12 mm.
3.制绒：采用常规化学清洗和织构化方法进行清洗和织构化，去除硅片表面的损伤层，降低光生载流子的复合速率；同时在硅片表面制成绒面降低反射率。3. Texturing: cleaning and texturing are carried out by conventional chemical cleaning and texturing methods to remove the damaged layer on the surface of the silicon wafer and reduce the recombination rate of the photo-generated carriers. At the same time, the surface of the silicon wafer is made into a suede to reduce the reflectivity. .
4.扩散：使用POCl 3扩散源进行高温(温度为840℃)背靠背单面扩散，扩散方阻控制在60Ω/□； 4. Diffusion: using a POCl 3 diffusion source for high temperature (temperature 840 ° C) back-to-back single-sided diffusion, diffusion resistance is controlled at 60 Ω / □;
5.掩膜：通过印刷，在扩散面制备如图2所示图案(与正电极图形对应)的掩膜图案，同时在孔洞内制备掩膜层。所用的掩膜浆料为石蜡或抗酸高分子材料， 膜厚为5-30μm。5. Mask: A mask pattern of a pattern (corresponding to a positive electrode pattern) as shown in Fig. 2 was prepared on the diffusion surface by printing while a mask layer was prepared in the hole. The masking paste used is a paraffin or acid-resistant polymer material having a film thickness of 5 to 30 μm.
6.刻蚀：采用常规化学法去除扩散后硅片周边及背面的PN结；采用常规化学法对掩膜图形以外正面扩散层进行抛结，抛结后的方阻控制在105Ω/□；采用碱去除正面及孔洞内的掩膜浆料；去除磷硅玻璃，并进行背面抛光；6. Etching: The PN junction on the periphery and the back of the silicon wafer after diffusion is removed by conventional chemical method; the front diffusion layer outside the mask pattern is thrown by conventional chemical method, and the square resistance after the junction is controlled at 105 Ω/□; The alkali removes the mask slurry in the front side and the hole; removes the phosphosilicate glass, and performs backside polishing;
7.背面钝化层制备：采用化学气相沉积(CVD)在电池片背面镀一层3nm厚度的Al 2O 3钝化膜； 7. Back passivation layer preparation: a 3 nm thick Al 2 O 3 passivation film is deposited on the back side of the cell by chemical vapor deposition (CVD);
8.正面减反膜：采用PECVD设备制备折射率在2.06，膜厚在85nm的氮化硅减反膜；8. Front side anti-reflection film: a silicon nitride anti-reflection film having a refractive index of 2.06 and a film thickness of 85 nm is prepared by a PECVD apparatus;
9.背面保护膜：采用PECVD设备制备折射率在2.10，膜厚在120nm的氮化硅减反膜；9. Back protective film: a silicon nitride anti-reflection film having a refractive index of 2.10 and a film thickness of 120 nm is prepared by a PECVD apparatus;
10.激光开槽：用激光将背面的氧化铝和氮化硅保护膜开槽；10. Laser grooving: use a laser to sag the aluminum oxide and silicon nitride protective film on the back side;
11.背面电极制备：采用丝网印刷方式，在电池片背面制备MWT背面电极的正极、背面电极的负极和进行堵孔，如图4所示图案；11. Preparation of the back electrode: by screen printing, the positive electrode of the back electrode of the MWT and the negative electrode of the back electrode are prepared on the back side of the cell sheet, and the hole is blocked, as shown in FIG. 4;
12.铝背场制备：采用丝网印刷方式，在电池片背面制备如图5所示的铝背场，印刷时避开MWT电池背面的正极、负极和激光打孔的孔洞；12. Aluminum back field preparation: The aluminum back field shown in Fig. 5 is prepared on the back side of the battery sheet by screen printing, and the positive electrode, the negative electrode and the laser perforated hole on the back surface of the MWT battery are avoided during printing;
13.正面电极：采用丝网印刷方式在MWT电池片正面制备如图6所示的正面电极。13. Front electrode: A front electrode as shown in Fig. 6 was prepared on the front side of the MWT cell by screen printing.
14.烧结：将印刷后浆料的电池片共烧(温度为760℃)形成欧姆接触。14. Sintering: The cell sheets of the post-printing paste were co-fired (temperature 760 ° C) to form an ohmic contact.
实施例2Example 2
本实施例高效MWT太阳能电池的制备方法如下：The preparation method of the high efficiency MWT solar cell of this embodiment is as follows:
1.硅片：采用太阳能级P型单晶或多晶硅片作为衬底；1. Wafer: using solar grade P-type single crystal or polycrystalline silicon wafer as the substrate;
2.激光打孔：将电池片按图1的MWT孔洞点阵图形，使用激光器在电池片上开孔，孔洞为圆形，直径为0.12mm。2. Laser drilling: According to the dot pattern of the MWT hole in Fig. 1, the laser is used to open a hole in the cell sheet, and the hole is circular and has a diameter of 0.12 mm.
3.制绒：采用常规化学清洗和织构化方法进行清洗和织构化，去除硅片表面的损伤层，降低光生载流子的复合速率；同时在硅片表面制成绒面降低反射率；3. Texturing: cleaning and texturing are carried out by conventional chemical cleaning and texturing methods to remove the damaged layer on the surface of the silicon wafer and reduce the recombination rate of the photo-generated carriers. At the same time, the surface of the silicon wafer is made into a suede to reduce the reflectivity. ;
4.扩散：使用POCl 3扩散源进行高温(温度为840℃)背靠背单面扩散，扩散方阻控制在50Ω/□； 4. Diffusion: using a POCl 3 diffusion source for high temperature (temperature 840 ° C) back-to-back single-sided diffusion, diffusion resistance is controlled at 50 Ω / □;
5.掩膜：通过印刷，在扩散面制备如图3所示图案(与正电极图形对应，无主栅线)的掩膜图案，同时在孔洞内制备掩膜层。所用的掩膜浆料为石蜡或抗酸高分子材料，膜厚为5-30μm。5. Mask: A mask pattern of a pattern (corresponding to a positive electrode pattern, no main gate line) as shown in FIG. 3 was prepared on the diffusion surface by printing, and a mask layer was prepared in the hole. The masking paste used was a paraffin wax or an acid-resistant polymer material having a film thickness of 5 to 30 μm.
6.刻蚀：采用常规化学法去除扩散后硅片周边及背面的PN结；采用常规化学法对掩膜图形以外正面扩散层进行抛结，抛结后的方阻控制在95Ω/□；采用 碱去除正面及孔洞内的掩膜浆料；去除磷硅玻璃，并进行背面抛光；6. Etching: The PN junction around the diffusion and the back surface of the silicon wafer is removed by conventional chemical method; the front diffusion layer outside the mask pattern is thrown by conventional chemical method, and the square resistance after the junction is controlled at 95 Ω/□; The alkali removes the mask slurry in the front side and the hole; removes the phosphosilicate glass, and performs backside polishing;
7.背面钝化层制备：采用化学气相沉积(CVD)在电池片背面镀一层2nm厚度的Al 2O 3钝化膜； 7. Back passivation layer preparation: a 2 nm thick Al 2 O 3 passivation film is deposited on the back side of the cell by chemical vapor deposition (CVD);
8.正面减反膜：采用PECVD设备制备折射率在2.06之间，膜厚在88nm的氮化硅减反膜；8. Frontal anti-reflection film: a silicon nitride anti-reflection film having a refractive index of 2.06 and a film thickness of 88 nm is prepared by a PECVD apparatus;
9.背面保护膜：采用PECVD设备制备折射率在2.08之间，膜厚在120nm的氮化硅减反膜；9. Back protective film: a silicon nitride anti-reflection film having a refractive index of 2.08 and a film thickness of 120 nm is prepared by a PECVD apparatus;
10.激光开槽：用激光将背面的氧化铝和氮化硅保护膜开槽；10. Laser grooving: use a laser to sag the aluminum oxide and silicon nitride protective film on the back side;
11.背面电极制备：采用丝网印刷方式，在电池片背面制备MWT背面电极的正极、背面电极的负极和进行堵孔，如图4所示图案；11. Preparation of the back electrode: by screen printing, the positive electrode of the back electrode of the MWT and the negative electrode of the back electrode are prepared on the back side of the cell sheet, and the hole is blocked, as shown in FIG. 4;
12.铝背场制备：采用丝网印刷方式，在电池片背面制备如图5所示的铝背场，印刷时避开MWT电池背面的正极、负极和激光打孔的孔洞。12. Aluminum back field preparation: The aluminum back field shown in Fig. 5 was prepared on the back side of the battery sheet by screen printing, and the positive electrode, the negative electrode and the laser perforated hole on the back of the MWT battery were avoided during printing.
13.正面电极：采用丝网印刷方式在MWT电池片正面制备如图6所示的正面电极。13. Front electrode: A front electrode as shown in Fig. 6 was prepared on the front side of the MWT cell by screen printing.
14.烧结：将印刷后浆料的电池片共烧(温度为760℃)形成欧姆接触。14. Sintering: The cell sheets of the post-printing paste were co-fired (temperature 760 ° C) to form an ohmic contact.
实施例3Example 3
本实施例高效MWT太阳能电池的制备方法如下：The preparation method of the high efficiency MWT solar cell of this embodiment is as follows:
1.硅片：采用太阳能级P型单晶或多晶硅片作为衬底；1. Wafer: using solar grade P-type single crystal or polycrystalline silicon wafer as the substrate;
2.制绒：采用常规化学清洗和织构化方法进行清洗和织构化，去除硅片表面的损伤层，降低光生载流子的复合速率；同时在硅片表面制成绒面降低反射率。2. Texturing: cleaning and texturing are carried out by conventional chemical cleaning and texturing methods to remove the damaged layer on the surface of the silicon wafer and reduce the recombination rate of the photo-generated carriers. At the same time, the surface of the silicon wafer is made into a suede to reduce the reflectivity. .
3.扩散：使用POCl 3扩散源进行高温(温度为840℃)背靠背单面扩散，扩散方阻控制在50Ω/□； 3. Diffusion: using a POCl 3 diffusion source for high temperature (temperature 840 ° C) back-to-back single-sided diffusion, diffusion resistance is controlled at 50 Ω / □;
4.掩膜：通过印刷，在扩散面制备如图3所示图案(与正电极图形对应，无主栅线)的掩膜图案。所用的掩膜浆料为石蜡或抗酸高分子材料，膜厚为5-30μm。4. Mask: A mask pattern of a pattern (corresponding to a positive electrode pattern, without a main gate line) as shown in FIG. 3 was prepared on the diffusion surface by printing. The masking paste used was a paraffin wax or an acid-resistant polymer material having a film thickness of 5 to 30 μm.
5.刻蚀：采用常规化学法去除扩散后硅片周边及背面的PN结；采用常规化学法对掩膜图形以外正面扩散层进行抛结，抛结后的方阻控制在100Ω/□；采用碱去除正面的掩膜浆料；去除磷硅玻璃，并进行背面抛光；5. Etching: The PN junction on the periphery and the back of the silicon wafer after diffusion is removed by conventional chemical method; the front diffusion layer outside the mask pattern is thrown by conventional chemical method, and the square resistance after the junction is controlled at 100 Ω/□; Alkali removes the masking paste on the front side; removes the phosphorous silicon glass and performs backside polishing;
6.背面钝化层制备：采用化学气相沉积(CVD)在电池片背面镀一层2nm厚度的Al 2O 3钝化膜； 6. Back passivation layer preparation: a 2 nm thick Al 2 O 3 passivation film is deposited on the back side of the cell by chemical vapor deposition (CVD);
7.正面减反膜：采用PECVD设备制备折射率在2.02之间，膜厚在80nm的氮化硅减反膜；7. Front side anti-reflection film: a silicon nitride anti-reflection film having a refractive index of 2.02 and a film thickness of 80 nm is prepared by a PECVD apparatus;
8.背面保护膜：采用PECVD设备制备折射率在2.08之间，膜厚在120nm的氮化硅减反膜；8. Back protective film: a silicon nitride anti-reflection film having a refractive index of 2.08 and a film thickness of 120 nm is prepared by a PECVD apparatus;
9.激光开槽：用激光将背面的氧化铝和氮化硅保护膜开槽；9. Laser grooving: use a laser to sag the aluminum oxide and silicon nitride protective film on the back side;
10.背面电极制备：采用丝网印刷方式，在电池片背面制备MWT背面电极的正极、如图7所示图案；10. Preparation of the back electrode: The positive electrode of the back electrode of the MWT is prepared on the back side of the cell sheet by screen printing, as shown in FIG. 7;
11.铝背场制备：采用丝网印刷方式，在电池片背面制备如图5所示的铝背场，印刷时避开MWT电池背面的正极、负极和激光打孔的孔洞。11. Aluminum back field preparation: The aluminum back field shown in Fig. 5 was prepared on the back side of the battery sheet by screen printing, and the positive electrode, the negative electrode and the laser perforated hole on the back side of the MWT battery were avoided during printing.
12.正面电极：采用丝网印刷方式在MWT电池片正面制备如图6所示的正面电极。12. Front electrode: A front electrode as shown in Fig. 6 was prepared on the front side of the MWT cell by screen printing.
13.烧结：将印刷后浆料的电池片共烧(温度为760℃)形成欧姆接触。13. Sintering: The cell sheets of the post-printing paste were co-fired (temperature 760 ° C) to form an ohmic contact.
14.激光打孔：将电池片按图1的MWT孔洞点阵图形，使用激光器在电池片上开孔，孔洞为圆形，直径为0.12mm。14. Laser drilling: The cell sheet is patterned according to the MWT hole pattern of Fig. 1, and the laser is used to make holes in the cell sheet. The hole is circular and has a diameter of 0.12 mm.
15.印刷导电胶：在激光开孔的孔洞区，印刷导电胶(具体可以为贺利氏SOL570。)形成背面电极的负极、堵孔并与正面电极图形相连通形成电流通路，如图8所示图案；15. Printing conductive adhesive: in the hole area of the laser opening, printing conductive adhesive (specifically, Heraeus SOL570) to form the negative electrode of the back electrode, plugging the hole and connecting with the front electrode pattern to form a current path, as shown in Figure 8. Display pattern
16.烘干：采用50°-200°的温度，烘干固化导电胶。16. Drying: Drying and curing the conductive adhesive with a temperature of 50°-200°.
打孔工序越靠后，整体碎片率越低，实施例3的打孔工序在最后，相比实施例1-2的碎片率降低0.5％，采用导电胶方式(实施例3)较常规银浆堵孔工艺(实施例1-2)的成本降低，A级品率可以提升0.5％-1％。The lower the punching process, the lower the overall chipping rate. At the end of the punching process of Example 3, the chipping rate of Example 1-2 was reduced by 0.5%, and the conductive paste method (Example 3) was compared with the conventional silver paste. The cost of the plugging process (Example 1-2) is reduced, and the grade A product rate can be increased by 0.5% to 1%.
上述实施例中涉及的图1-图8图案为现有太阳能电池制备中的图案，本发明不仅限于上述图案，可采用其他的图形设计。The patterns of FIGS. 1-8 in the above embodiments are patterns in the preparation of existing solar cells, and the present invention is not limited to the above-described patterns, and other graphic designs may be employed.

Claims (8)

  1. 一种高效MWT太阳能电池的制备方法，其特征在于，包括：将制绒扩散后的硅片经掩膜工序后再进行刻蚀工序，刻蚀工序结束后依次进行以下工序：A method for preparing a high-efficiency MWT solar cell, comprising: performing a etching process after the flock-spreading silicon wafer is subjected to a masking process, and performing the following steps after the etching process is completed:
    (a)背面钝化层制备：在电池片背面制备一层钝化层；(a) preparation of the back passivation layer: preparing a passivation layer on the back side of the cell sheet;
    (b)正面减反膜：在电池片正面制备一层减反膜；(b) front anti-reflection film: preparing a layer of anti-reflection film on the front side of the cell sheet;
    (c)背面保护膜：在电池片背面钝化层上覆一层保护膜；(c) back protective film: a protective film is coated on the passivation layer on the back side of the battery sheet;
    (d)开槽：将背面的减反膜和保护膜开槽，以便铝背场浆料和硅基体形成欧姆接触；(d) Slotting: grooving the anti-reflection film and the protective film on the back surface so that the aluminum back field paste forms an ohmic contact with the silicon substrate;
    其中，掩膜工序包括在硅片扩散面制备正电极图案对应的掩膜图案；刻蚀工序包括去除硅片周边及背面的PN结，对掩膜图形以外正面扩散层进行抛结，去除掩膜浆料，去除磷硅玻璃，并进行背面抛光。The masking process includes preparing a mask pattern corresponding to the positive electrode pattern on the diffusion surface of the silicon wafer; the etching step includes removing the PN junction around the silicon wafer and the back surface, and depositing the front diffusion layer outside the mask pattern to remove the mask. The slurry is removed from the phosphosilicate glass and backside polished.
  2. 根据权利要求1所述的高效MWT太阳能电池的制备方法，其特征在于，采用碱或二乙二醇单丁醚去除掩膜浆料。The method for preparing a high-efficiency MWT solar cell according to claim 1, wherein the mask slurry is removed using alkali or diethylene glycol monobutyl ether.
  3. 根据权利要求1所述的高效MWT太阳能电池的制备方法，其特征在于，钝化层为氧化铝或氧化硅，钝化层的厚度为1-50nm。The method for preparing a high-efficiency MWT solar cell according to claim 1, wherein the passivation layer is aluminum oxide or silicon oxide, and the passivation layer has a thickness of 1 to 50 nm.
  4. 根据权利要求1所述的高效MWT太阳能电池的制备方法，其特征在于，减反膜为氮化硅，折射率为1.9-2.2，膜厚为60-100nm；保护膜为氮化硅，折射率为1.9-2.2，膜厚为10-150nm。The method for preparing a high-efficiency MWT solar cell according to claim 1, wherein the anti-reflection film is silicon nitride, the refractive index is 1.9-2.2, and the film thickness is 60-100 nm; the protective film is silicon nitride, and the refractive index is It is 1.9-2.2 and the film thickness is 10-150 nm.
  5. 根据权利要求1所述的高效MWT太阳能电池的制备方法，其特征在于，硅片在经制绒扩散前先进行打孔，在硅片上形成用于填充浆料将正面电极汇集的电流引至基片背面的孔洞；掩膜工序时在孔洞内制备掩膜层。The method for fabricating a high-efficiency MWT solar cell according to claim 1, wherein the silicon wafer is perforated before being subjected to texturing diffusion, and a current for filling the slurry on the silicon wafer is introduced to the front electrode. A hole in the back surface of the substrate; a mask layer is prepared in the hole during the masking process.
  6. 根据权利要求5所述的高效MWT太阳能电池的制备方法，其特征在于，包括：The method for preparing a high-efficiency MWT solar cell according to claim 5, comprising:
    (1)打孔；(1) punching;
    (2)制绒：对硅片进行清洗和织构化，去除硅片表面的损伤层，在硅片表面制成绒面；(2) Texturing: cleaning and texturing the silicon wafer, removing the damaged layer on the surface of the silicon wafer, and forming a suede surface on the surface of the silicon wafer;
    (3)扩散：在硅片衬底沉积掺杂源并进行扩散制备PN结；(3) diffusion: depositing a doping source on the silicon substrate and performing diffusion to prepare a PN junction;
    (4)掩膜；(4) mask;
    (5)刻蚀；(5) etching;
    (6)背面钝化层制备；(6) preparation of the back passivation layer;
    (7)正面减反膜；(7) positive anti-reflection film;
    (8)背面保护膜；(8) back protective film;
    (9)开槽；(9) slotting;
    (10)背面电极制备：在电池片片背面制备MWT背面电极的正极、背面电 极的负极和进行堵孔；(10) Preparation of the back electrode: preparing the positive electrode of the back surface electrode of the MWT and the negative electrode of the back electrode on the back side of the battery piece and blocking the hole;
    (11)铝背场制备：在电池片背面制备铝背场；(11) Aluminum back field preparation: preparing an aluminum back field on the back side of the battery sheet;
    (12)正面电极制备：在电池片正面制备正面电极；(12) Front electrode preparation: preparing a front electrode on the front side of the battery sheet;
    (13)烧结：将电池片共烧形成欧姆接触。(13) Sintering: The battery sheets were co-fired to form an ohmic contact.
  7. 根据权利要求1所述的高效MWT太阳能电池的制备方法，其特征在于，包括：The method for preparing a high-efficiency MWT solar cell according to claim 1, comprising:
    (1)制绒：对硅片进行清洗和织构化，去除硅片表面的损伤层，在硅片表面制成绒面；(1) Texturing: cleaning and texturing the silicon wafer, removing the damaged layer on the surface of the silicon wafer, and forming a suede surface on the surface of the silicon wafer;
    (2)扩散：在硅片衬底沉积掺杂源并进行扩散制备PN结；(2) diffusion: depositing a doping source on the silicon substrate and performing diffusion to prepare a PN junction;
    (3)掩膜；(3) mask;
    (4)刻蚀；(4) etching;
    (5)背面钝化层制备；(5) preparation of the back passivation layer;
    (6)正面减反膜；(6) positive anti-reflection film;
    (7)背面保护膜；(7) a back protective film;
    (8)开槽；(8) slotting;
    (9)背面电极制备：在硅片背面制备MWT背面电极的正极；(9) preparation of the back electrode: preparing the anode of the back electrode of the MWT on the back side of the silicon wafer;
    (10)铝背场制备：在硅片背面制备铝背场；(10) Aluminum back field preparation: preparing an aluminum back field on the back side of the silicon wafer;
    (11)正面电极制备：在电池片正面制备正面电极；(11) Front electrode preparation: preparing a front electrode on the front side of the battery sheet;
    (12)烧结：将电池片共烧形成欧姆接触；(12) sintering: co-firing the battery sheets to form an ohmic contact;
    (13)打孔：在电池片上打孔，形成用于填充浆料将正面电极汇集的电流引至电池片背面的孔洞；(13) Punching: punching a hole in the battery sheet to form a hole for filling the slurry to direct the current collected by the front electrode to the back surface of the battery sheet;
    (14)印刷导电胶：用导电胶填充孔洞并制成背面电极的负极，与正面电极相连通形成电流通路；(14) printing conductive adhesive: filling the hole with conductive glue and forming the negative electrode of the back electrode, and connecting with the front electrode to form a current path;
    (15)烘干：烘干固化导电胶。(15) Drying: drying and curing the conductive adhesive.
  8. 根据权利要求6或7所述的高效MWT太阳能电池的制备方法，其特征在于，硅片采用背靠背的方式进行单面扩散，扩散源为POCl3，扩散方阻为30-100Ω/□。The method for preparing a high-efficiency MWT solar cell according to claim 6 or 7, wherein the silicon wafer is diffused on one side in a back-to-back manner, the diffusion source is POCl3, and the diffusion square resistance is 30-100 Ω/□.
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