WO2023232057A1 - 一种栅线的制备方法、电池片的制备方法及光伏电池 - Google Patents

一种栅线的制备方法、电池片的制备方法及光伏电池 Download PDF

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Publication number
WO2023232057A1
WO2023232057A1 PCT/CN2023/097324 CN2023097324W WO2023232057A1 WO 2023232057 A1 WO2023232057 A1 WO 2023232057A1 CN 2023097324 W CN2023097324 W CN 2023097324W WO 2023232057 A1 WO2023232057 A1 WO 2023232057A1
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WIPO (PCT)
Prior art keywords
mask
layer
battery sheet
area
width
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PCT/CN2023/097324
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English (en)
French (fr)
Inventor
姚宇
李中天
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苏州太阳井新能源有限公司
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Priority claimed from CN202221378822.XU external-priority patent/CN217361599U/zh
Application filed by 苏州太阳井新能源有限公司 filed Critical 苏州太阳井新能源有限公司
Publication of WO2023232057A1 publication Critical patent/WO2023232057A1/zh

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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
    • H01L31/02—Details
    • H01L31/0224—Electrodes
    • 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
    • H01L31/04—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 adapted as photovoltaic [PV] conversion devices
    • H01L31/054—Optical elements directly associated or integrated with the PV cell, e.g. light-reflecting means or light-concentrating means
    • 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

Definitions

  • the invention relates to the field of photovoltaic cell manufacturing, and specifically relates to a grid line preparation method, a cell sheet preparation method and a photovoltaic cell.
  • the silver paste is transferred to the substrate after passing through the pre-made openings of the screen to form unsolidified grid lines.
  • the unsolidified The contact point between the grid lines and the screen yarn is pulled up.
  • the unsolidified grid lines have a certain leveling property, resulting in the final formed grid lines having a semicircle-like longitudinal section that is wider at the bottom and narrower at the top.
  • the shape of the arc is called an arc-shaped grid line.
  • the use of copper electroplating instead of screen printing silver paste to make grid lines of photovoltaic cells is receiving more and more attention and research.
  • the mask opening of the copper electroplating is usually rectangular or approximately rectangular, so that the longitudinal section of the formed gate line is rectangular or approximately rectangular, which is called a rectangular gate line.
  • rectangular grid lines cannot increase the reflection of the grid line surface in all directions. Therefore, after the component is packaged, it will cause packaging losses that exceed those of arc-shaped grid lines, which will affect the power generation efficiency and the power generation amount during the life cycle.
  • the antireflection effect of arc-shaped grating lines is characterized by the optical width of the grating line, which is usually 70% of the width at its physical widest point; the optical width of a rectangular grating line is usually 90% of the width at its physical widest point. above.
  • the present invention proposes a method for preparing grid lines, a method for preparing cells, and a photovoltaic cell, which reduce the optical width of the grid lines to improve the photoelectric conversion efficiency of the photovoltaic cells.
  • An object of the present invention is to provide a method for preparing a grid line to reduce the optical width of the grid line to improve the photoelectric conversion efficiency of the photovoltaic cell.
  • embodiments of the present invention provide a method for preparing gate lines, including:
  • the method of preparing the gate line further includes:
  • Step S6 Cover the surface of the grid line with a reflective layer or an alloy solder layer with a melting point lower than 300°C or with Machine protective layer;
  • step S6 is arranged after the step S4 and before the step S5, or the step S6 is arranged after the step S5.
  • the mask material is coated on both sides of the battery sheet, and the grid lines with a width gradient are formed at least on the light-receiving surface of the battery sheet; when the structure of the battery sheet is double In a planar power generation structure, the grid lines with a width gradient are formed on both sides of the battery sheet.
  • the aforementioned step S2 includes: exposing the areas on the mask that do not require openings, so that the curing degree of the mask gradually increases from the surface of the battery sheet to the surface away from the battery sheet, so as to A development reaction area with a width gradient is formed on the mask; or, the area on the mask that needs to be opened is exposed, so that the degree of solidification of the mask gradually decreases from the surface of the battery sheet to the surface away from the battery sheet.
  • the step S3 includes: according to the mask, the curing degree gradually increases from the surface of the battery sheet to the surface away from the battery sheet, or In a gradually decreasing situation, a corresponding developer is selected to react with the mask in the development reaction zone with a width gradient to form the mask opening with a width gradient.
  • a method of preparing a gate line includes the following steps:
  • the photosensitive component and/or the concentration of the photosensitive component is adjusted to form a multi-layer mask with different sensitivities
  • a method of preparing a gate line includes the following steps:
  • first metal and the second metal may be the same metal or different metals
  • the first area and the second area are both located on the same surface of the battery sheet, or the first area and the second area are located on two surfaces of the battery sheet respectively.
  • a mask material is coated on the side of the cell sheet, and the mask material is cured to form a mask.
  • a local area of the mask is exposed to form a development reaction area on the mask with a trapezoidal or stepped longitudinal cross-section
  • Metal is electroplated in the mask opening to form a gate line with a trapezoidal or stepped longitudinal cross-section.
  • the longitudinal section of the mask opening is a trapezoid, and the base angle of the trapezoid is 45-89 degrees.
  • a grid line with a triangular or trapezoidal longitudinal cross-section cannot be formed; the surface of the grid line is covered with a reflective layer or an alloy welding layer with a melting point lower than 300°C, or The organic protective layer makes the longitudinal cross-section of the gate line form a triangle or a trapezoid.
  • Another object of the present invention is to provide a method for preparing a battery sheet.
  • the grid lines on the battery sheet are prepared by using the following steps:
  • Another object of the present invention is to provide a photovoltaic cell including a grid line with a width gradient, which can reduce the optical width of the grid line.
  • the technical solution adopted in the embodiment of the present invention is: a photovoltaic cell.
  • the photovoltaic cell includes a cell sheet, and a grid line with a width gradient provided on the cell sheet.
  • the longitudinal section of the gate line is triangular, trapezoidal, or stepped.
  • the surface of the gate line is also covered with a bright tin or bright silver reflective layer; or
  • the surface of the gate line is covered with an alloy solder layer with a melting point lower than 300° C., and the alloy solder layer is formed of tin and one or more of lead, bismuth, silver, copper, indium and zinc; or
  • the surface of the gate line is covered with an organic protective layer.
  • At least the light-receiving surface of the battery sheet is provided with the grid lines, or both sides of the battery sheet are provided with the grid lines.
  • the materials of the multiple grid lines located on the same surface of the battery sheet are different metals and/or the materials of the multiple grid lines located on different surfaces of the battery sheet. for different metals.
  • the minimum line width of the gate line is less than 50 microns and greater than or equal to 5 microns.
  • the embodiments of the present invention have the following advantages compared with the prior art: through the preparation method of the gate lines according to the embodiments of the present invention, gate lines with a width gradient can be formed on the battery sheet. After the grid lines are packaged into photovoltaic modules, they have the effect of reflecting incident light at multiple angles; and this reflection can be reflected back to the surface of the cell at the material interface inside the photovoltaic module, thereby increasing power generation efficiency.
  • the gate line preparation method in the embodiment of the present invention has a simple process and is convenient for large-scale industrial application.
  • Figure 1 is a schematic flow chart of a method for preparing gate lines in the first embodiment of the present invention
  • Figure 1-1 is a schematic diagram of the illumination of the exposure mask in the first embodiment of the present invention.
  • Figures 1-2 are schematic diagrams of a development reaction zone with a width gradient in the first embodiment of the present invention
  • 1-3 are schematic diagrams of mask openings with width gradients in the first embodiment of the present invention.
  • 1-4 are schematic diagrams of gate lines with width gradients in the first embodiment of the present invention.
  • Figures 1-5 are schematic diagrams of the solar cells after removing the mask in the first embodiment of the present invention.
  • Figures 1-6 are schematic diagrams of the surface of the gate lines after coating in the first embodiment of the present invention.
  • Figure 2 is a schematic flow chart of a method for preparing gate lines in a second embodiment of the present invention
  • Figure 2-1 is a schematic diagram of the illumination of the exposure mask in the second embodiment of the present invention.
  • Figure 2-2 is a schematic diagram of a development reaction zone with a width gradient in a second embodiment of the present invention.
  • Figures 2-3 are schematic diagrams of mask openings with width gradients in a second embodiment of the present invention.
  • FIGS 2-5 are schematic diagrams of the coating gap in the second embodiment of the present invention.
  • Figures 2-6 are schematic diagrams of the surface of the gate lines after coating in the second embodiment of the present invention.
  • Figures 2-7 are schematic diagrams of the solar cells after removing the mask in the second embodiment of the present invention.
  • Figure 3 is a schematic flow chart of the preparation method of the development reaction zone in the third embodiment of the present invention.
  • Figure 3-1 is a schematic structural diagram of a battery sheet covered with a mask in the third embodiment of the present invention.
  • Figure 3-2 is a schematic diagram of the first exposure result in the third embodiment of the present invention.
  • Figure 3-3 is a schematic diagram of the second exposure result in the third embodiment of the present invention.
  • Figures 3-4 are schematic diagrams of the third exposure results in the third embodiment of the present invention.
  • Figure 4 is a schematic flow chart of the preparation method of the development reaction zone in the fourth embodiment of the present invention.
  • Figure 4-1 is a schematic structural diagram of a solar cell sheet covered with a mask in the fourth embodiment of the present invention.
  • Figure 4-2 is a schematic diagram of the first exposure result in the fourth embodiment of the present invention.
  • Figure 4-3 is a schematic diagram of the second exposure result in the fourth embodiment of the present invention.
  • Figure 4-4 is a schematic diagram of the third exposure result in the fourth embodiment of the present invention.
  • FIG. 5 is a schematic diagram of a longitudinal section of a gate line with a width gradient in a fifth embodiment of the present invention.
  • Figure 6 is a schematic flow chart of a method for preparing gate lines in the sixth embodiment of the present invention.
  • Figure 6-1 is a schematic structural diagram of a solar cell sheet covered with a mask in the sixth embodiment of the present invention.
  • Figure 6-2 is a schematic diagram of the exposure result of the first mask in the sixth embodiment of the present invention.
  • Figure 6-3 is a schematic diagram of the first mask opening on the first mask in the sixth embodiment of the present invention.
  • Figure 6-4 is a schematic diagram of the first gate line on the first mask in the sixth embodiment of the present invention.
  • Figure 6-5 is a schematic diagram of the exposure result of the second mask in the sixth embodiment of the present invention.
  • 6-6 is a schematic diagram of the second mask opening on the second mask in the sixth embodiment of the present invention.
  • Figures 6-7 are schematic diagrams of the second gate lines on the second mask in the sixth embodiment of the present invention.
  • Figures 6-8 are schematic structural diagrams of the cells after removing the mask in the sixth embodiment of the present invention.
  • Figure 7 is a schematic flow chart of a method for preparing gate lines in the seventh embodiment of the present invention.
  • Figure 7-1 is a schematic structural diagram of a solar cell sheet covered with a mask in the seventh embodiment of the present invention.
  • Figure 7-2 is a schematic diagram of the exposure result of the first mask in the seventh embodiment of the present invention.
  • Figure 7-3 is a schematic diagram of the first mask opening on the first mask in the seventh embodiment of the present invention.
  • Figure 7-4 is a schematic diagram of the first gate line on the first mask in the seventh embodiment of the present invention.
  • Figure 7-5 is a schematic diagram of the exposure result of the second mask in the seventh embodiment of the present invention.
  • Figures 7-6 are schematic diagrams of the second mask opening on the second mask in the seventh embodiment of the present invention.
  • FIG. 7-7 is a schematic diagram of the second gate line on the second mask in the seventh embodiment of the present invention.
  • Figures 7-8 are schematic structural diagrams of the cells after removing the mask in the seventh embodiment of the present invention.
  • the grid lines of photovoltaic cells are prepared by screen printing silver paste.
  • the silver paste is transferred to the substrate after passing through the pre-made openings in the screen to form unsolidified grid lines.
  • the screen is separated from the substrate, the contact between the unsolidified grid lines and the screen yarn is lifted, and the screen and screen are After the substrate is separated, the unsolidified grid lines have a certain leveling property, resulting in the final formed grid line having a semi-circular arc-like longitudinal section with a wide bottom and narrow top, which is called an arc-shaped grid line.
  • the use of copper electroplating instead of screen printing silver paste to make grid lines of photovoltaic cells is receiving more and more attention and research.
  • the mask opening of the copper electroplating is usually rectangular or approximately rectangular, so that the longitudinal section of the formed gate line is rectangular or approximately rectangular, which is called a rectangular gate line.
  • rectangular grid lines cannot increase the reflection of the grid line surface in all directions. Therefore, after the component is packaged, it will cause packaging losses that exceed those of arc-shaped grid lines, which will affect the power generation efficiency and the power generation amount during the life cycle.
  • the antireflection effect of arc-shaped grating lines is characterized by the optical width of the grating line, which is usually 70% of the width at its physical widest point; the optical width of a rectangular grating line is usually 90% of the width at its physical widest point. above.
  • the present invention proposes a method for preparing grid lines, a method for preparing cells, and a photovoltaic cell, which reduce the optical width of the grid lines to improve the photoelectric conversion efficiency of the photovoltaic cells.
  • the traditional screen printing process to prepare silver grid lines mainly has the following problems: first, The printing process requires pressure on the battery cells, which can easily lead to an increase in the defective rate of battery cells with a thickness of less than 100 microns. Secondly, the resolution of screen printing is low, and the aspect ratio of the printed silver grid lines is low. Due to the network lines of the silk screen, it is very difficult to reduce the current line width to less than 50 microns.
  • the silver paste In order for the silver paste to pass through the screen without breaking the line, the silver paste must have a certain fluidity, which makes the printed silver
  • the grid lines will flow outward, further increasing the line width (the width of the contact surface between the grid lines and the cell), reducing the aspect ratio, increasing the light-shielding area, and affecting the photoelectric conversion efficiency. Therefore, it is necessary to propose a method for preparing grid lines, a method for preparing cells, and a photovoltaic cell, which can prepare grid lines with low line width, reduce the shading area of the grid lines, and improve the photoelectric conversion efficiency of photovoltaic cells.
  • the shading generated by the grid line will reduce the short-circuit current, and the reduction ratio is proportional to the shading area.
  • the short-circuit current in the non-shielding area is 40mA/cm 2
  • the short-circuit current will be 39.2mA/cm 2
  • a grid line has no width gradient
  • the short-circuit current in the unshielded area is 40mA/ cm2
  • the physical shielding area formed by the grid line is 3%
  • an optical shielding area of 3% is formed.
  • the short circuit current is 38.8mA/cm 2 .
  • a gate line has a width gradient, when the short-circuit current in the non-shielding area is 40mA/ cm2 , and the physical blocking is 3% of the area, only 2% of the optical blocking area is actually generated, so the short-circuit current obtained is 39.2 mA/cm 2 .
  • the short-circuit current obtained by a cell with a grid line having a width gradient is greater than the short-circuit current obtained by a cell without a grid line having a width gradient, that is, the photoelectric conversion efficiency of a cell with a grid line having a width gradient is higher. high.
  • an embodiment of the present invention provides a method for preparing a gate line, which includes the following steps:
  • the grid line preparation method in the embodiment of the present invention can form grid lines 4 with a width gradient on the surface of the cell sheet 1.
  • the cell sheet 1 has a width gradient when used, especially after being packaged into a photovoltaic module.
  • the grid lines 4 can reflect incident light at multiple angles, so that the incident light can be reflected back to the surface of the cell sheet 1 at the material interface inside the photovoltaic module, thereby increasing the power generation efficiency of the cell sheet.
  • the existing screen printing technology cannot directly print grid lines 4 with a width gradient. Even if a grid line 4 with a width gradient can be obtained by chance, the width gradients of each grid line 4 on the same cell piece 1 are different, or It is said that the width gradient of each grid line 4 on the same cell piece 1 is inconsistent, resulting in a reduction in the anti-reflection effect.
  • the gate line preparation method in the embodiment of the present invention can be obtained by photolithography (development and exposure). A mask opening 3 with a uniform width gradient is obtained, and then metal is electroplated in the mask opening 3 with a uniform width gradient, so that a gate line 4 with a uniform width gradient can be obtained, and a better antireflection effect can be obtained.
  • the two surfaces perpendicular to the thickness direction of the battery sheet 1 are the front and back sides, or the two larger surfaces arranged opposite to each other on the battery sheet 1 are the front and back surfaces; the surface extending along the thickness direction of the battery sheet 1 is the side. Or all sides except the front and back are side faces.
  • the light-receiving surface of the cell 1 refers to one or both sides of the cell 1 that can receive light and generate electricity when in use, and can be the front and/or the back.
  • exposure refers to a photochemical reaction process in which the mask 2 and light undergo photocrosslinking, polymerization, or decomposition.
  • Developing refers to a process in which the mask 2 that has not undergone a photochemical reaction or that has undergone a photochemical reaction further reacts with the developer to form a mask gap 3 .
  • the width gradient refers to the phenomenon that the width value of the object changes from top to bottom along the up and down direction of the object. If the object is divided into multiple layers distributed from top to bottom, then there is a layer below the top layer. At least one width expansion layer, the width of the width expansion layer is greater than the width of any layer above it. Specifically, the object is divided into layer 1, layer 2, and... layer N from top to bottom. The above N is a positive integer greater than 1, where layer 1 is the top layer and layer N is the bottom layer. The bottom layer is adjacent to the surface of the cell.
  • the above-mentioned width expansion layer is a relative concept. If the width of the second layer is greater than the width of the first layer, the second layer is a width expansion layer; the width of the fourth layer is greater than that of any of the first to third layers. width, then the fourth layer is the width expansion layer.
  • a more representative width gradient is the phenomenon in which the width value of an object increases from top to bottom, especially if the vertical cross-section is a triangle, a trapezoid with a narrow top and a wide bottom, or a stepped shape with a narrow top and a wide bottom.
  • the longitudinal section of the development reaction zone is a trapezoid that is narrow at the top and wide at the bottom, or a step shape with a narrow top and a wide bottom, which can be regarded as the development reaction zone having a width gradient;
  • the longitudinal section of the mask opening 3 is a trapezoid with a narrow top and a wide bottom, or a narrow top and a wide bottom.
  • the wide step shape can be regarded as the mask opening 3 having a width gradient;
  • the longitudinal cross-section of the gate line 4 is a triangle, a trapezoid with a narrow top and a wide bottom, or a stepped shape with a narrow top and a wide bottom, which can be considered as a width gradient of the gate line 4 .
  • the width gradient of the object includes but is not limited to the above examples.
  • the material of the mask 2 can be an acid-resistant material, and the mask 2 can be removed by soaking in an alkaline solution, such as an alkaline solution formed by at least one of sodium hydroxide, potassium hydroxide, or calcium hydroxide. .
  • the preparation method also includes step S6, covering the surface of the grid line 4 with a reflective layer or an alloy solder layer with a melting point lower than 300°C or an organic protective layer.
  • the reflective layer, alloy solder layer and organic protective layer are collectively referred to as covering.
  • the alloy solder layer is formed of tin and one or more of lead, bismuth, silver, copper, indium and zinc. Covering the surface of the grid line 4 with the above-mentioned reflective layer, alloy solder layer or organic protective layer can make the reflective layer, alloy solder layer or organic protective layer form an approximately triangular or trapezoidal shape after being heated, melted and reflowed.
  • step S6 the surface of the grid line 4 is covered with a reflective layer or an alloy welding layer or an organic protective layer, thereby improving the reflection effect of the surface of the grid line 4, improving the welding performance of the surface of the grid line 4, or protecting the surface of the grid line 4.
  • the function of being protected from chemical corrosion also makes the surface of the grid line 4 smoother and improves the anti-reflection effect of the grid line 4.
  • the reflective layer or alloy solder layer or organic protective layer can be used as a compensation material to make up for the step space on the grid line 4, so that the longitudinal section of the grid line 4 forms an approximately triangular shape. or trapezoid to improve the antireflection effect of gate line 4.
  • the surface of gate line 4 is covered with reverse
  • the shot layer, alloy welding layer or organic protective layer can be prepared by electroplating or chemical plating or coating.
  • step S6 can be performed after step S5, that is, after removing the mask 2, the surface of the gate line 4 is covered with a reflective layer or an alloy solder layer or an organic protective layer, which makes it easier to form a reflection. layer or alloy solder layer or organic protective layer to avoid the interference of the mask 2 and improve the preparation efficiency of the gate line 4.
  • step S6 can also be arranged after step S4 and before step S5 , that is, the surface of the gate line 4 is first covered with a reflective layer or an alloy solder layer or an organic protective layer and then the mask 2 is removed.
  • a mask material is coated on both sides (front and back) of the cell sheet 1, and a mask 2 is formed on both sides of the cell sheet 1, at least on the light-receiving surface of the cell sheet 1 to form a mask material with a width gradient.
  • a mask material is applied to both sides (front and back) of the battery sheet 1 to form a mask 2 on both sides of the battery sheet 1; if the battery sheet 1 has a single-sided power generation structure, that is, the battery sheet only has One side (front or back) is the light-receiving surface, and only part of the mask 2 on the light-receiving surface is exposed and developed to form a mask opening 3 with a width gradient, and then metal is electroplated in the mask opening 3 with a width gradient to form a Gate lines 4 with gradient width; if the cell 1 has a double-sided power generation structure, that is, both sides (front and back) of the cell are light-receiving surfaces, the partial masks 2 on both sides of the cell 1 are exposed and exposed respectively.
  • mask openings 3 with a width gradient on both sides of the battery sheet 1 then electroplating metal in the mask openings 3 with a width gradient, and form gates with a width gradient on both sides of the battery sheet 1 Line 4.
  • electroplating to form grid lines 4 if the non-opening areas on both sides of the cell sheet 1 are in direct contact with the plating solution, they will also be electroplated. Therefore, regardless of whether the cell sheet 1 has a double-sided power generation structure, both sides of the cell sheet 1 will be electroplated.
  • a mask 2 needs to be formed on both sides of the cell 1 to prevent the non-opening areas on both sides of the cell 1 from being plated.
  • the single-sided power generation structure cell 1 mentioned in the embodiment of the present application can be BSF (Al ⁇ mini ⁇ m Back Surface Field, aluminum back field battery), PERC (Passivated Emitter and Rear Cell, passivated emitter and rear cell) Battery), HJT (Heterojunction with Intrinsic Thin Layer, crystalline silicon heterojunction solar cell), PSC (Perovskite Solar Cells, perovskite battery) or IBC (Interdigitated Back Contact, interdigitated back contact battery) and other structural batteries.
  • the bifacial power generation structure battery sheet 1 mentioned in the embodiment of this application can be a HJT, Topcon (Tunnel Oxide Passivating Contacts, tunnel oxide layer passivating contact battery) or PSC structure battery.
  • At least the following method can be used to form a development reaction area with a width gradient: exposing an area on the mask 2 that does not require openings, so that the mask 2 is solidified from the surface of the battery sheet 1 toward the surface away from the battery sheet 1 The degree gradually increases to form a development reaction area with a width gradient on the mask 2; or, expose the area on the mask 2 that needs to be opened, so that the mask 2 moves from the surface of the battery sheet 1 to the surface direction away from the battery sheet 1 The degree of curing is gradually reduced to form a development reaction area with a width gradient on the mask 2;
  • At least the following method can be used to form the mask opening 3 with a width gradient: according to the situation where the degree of solidification of the mask 2 gradually increases or decreases from the surface of the battery sheet 1 to the surface away from the battery sheet 1, select the corresponding developer and The mask 2 in the development reaction area with a width gradient undergoes a development reaction, and the reaction rate of the development reaction gradually slows down from the surface of the battery sheet 1 to the surface direction away from the battery sheet 1 to form a mask opening 3 with a width gradient.
  • the following method is used to form a development reaction area with a width gradient: coating the surface of the cell sheet 1 to form a multi-layer mask 2, each layer of mask 2 having a different sensitivity; exposing the multi-layer mask The area on the film 2 that does not require openings causes the multi-layer mask 2 to be solidified layer by layer from the surface of the battery sheet 1 to the surface away from the battery sheet 1 to form a development reaction area with a width gradient on the mask 2 ; Or, expose the area on the multi-layer mask 2 that needs to be opened, so that the degree of solidification of the multi-layer mask 2 decreases layer by layer from the surface of the battery sheet 1 to the surface away from the battery sheet 1, so as to form a film with a width on the mask 2 Gradient development reaction zone; wherein the photosensitive component and/or the concentration of the photosensitive component is adjusted to form a multi-layer mask 2 with different sensitivities.
  • a uniform light source can be used for one-time exposure, the exposure process is simple,
  • a three-layer mask 2 is coated on the surface of the battery sheet 1.
  • Each layer of mask 2 has a different sensitivity.
  • the three-layer mask 2 moves away from the surface of the battery sheet 1.
  • the sensitivity of the surface direction of the cell 1 decreases layer by layer, that is, the layer (the bottom layer) of the mask 2 close to the surface of the cell 1 has the highest sensitivity, and the layer (the top layer) of the mask 2 far away from the surface of the cell 1 has the highest sensitivity. has the lowest sensitivity, and the sensitivity of the mask 2 located in the middle is smaller than the sensitivity of the adjacent next layer of mask 2 but greater than the sensitivity of the adjacent upper layer of mask 2.
  • the bottom mask 2 has the highest sensitivity. It absorbs the most energy of light, so that the bottom layer of mask 2 has the highest degree of curing and the largest curing area (that is, the volume of mask 2 that is cured is the largest); the top layer of mask 2 has the lowest sensitivity and absorbs the energy of light.
  • the mask 2 in the middle layer has a lower sensitivity than the adjacent next layer
  • the sensitivity of mask 2 is however greater than the sensitivity of the adjacent upper layer mask 2, so that the curing degree and curing area of the middle layer mask 2 is smaller than the adjacent lower layer mask 2 and greater than the adjacent upper layer.
  • a coordinate system is established with the surface of the cell 1 as the origin, the sensitivity is the dependent variable y, and the number of layers of the multi-layer mask 2 calculated upward from the surface of the cell 1 is the independent variable x.
  • the calculation formula of sensitivity y can be obtained y ⁇ ax n ⁇ b, a and n depend on the properties of mask 2, a is a positive number, mainly determined by the Determined by the concentration of the photosensitive component and/or the photosensitive component.
  • n is 1, the cross-section of the development reaction area formed after exposure of the multi-layer mask 2 is roughly ladder-shaped. For example, reference can be made to the graphics in Figures 5-1 and 5-2.
  • a coordinate system is established with the surface of the cell 1 as the origin, the sensitivity is the dependent variable y, and the distance between the mask 2 and the surface of the cell 1 is the independent variable x, that is, the height of the mask 2 on the cell 1 is x.
  • the calculation formula of sensitivity y can be obtained y ⁇ ax n ⁇ b, a and n depend on mask 2
  • a is a positive number, are mainly determined by the photosensitive component and/or the concentration of the photosensitive component in the mask 2. Theoretically, when n is 1, the cross-section of the development reaction area formed after the mask 2 is exposed is roughly trapezoidal or triangular.
  • a three-layer mask 2 is coated on the surface of the battery sheet 1.
  • Each layer of mask 2 has a different sensitivity.
  • the three-layer mask 2 moves away from the surface of the battery sheet 1.
  • the sensitivity of the surface direction of the cell 1 increases layer by layer, that is, the layer (the bottom layer) of the mask 2 close to the surface of the cell 1 has the lowest sensitivity, and the layer (the top layer) of the mask far away from the surface of the cell 1 has the lowest sensitivity. 2 has the highest sensitivity.
  • the sensitivity of the mask 2 located in the middle is greater than the sensitivity of the adjacent next layer mask 2 but less than the sensitivity of the adjacent upper layer mask 2.
  • the bottom layer Mask 2 has the lowest sensitivity and absorbs the least light energy, so that the bottom layer of mask 2 has the lowest degree of curing and the smallest curing area (that is, the volume of mask 2 that is cured is the least); the top layer of mask 2 It has the highest sensitivity and absorbs the most light energy, so that the uppermost layer of mask 2 has the highest degree of curing and the largest curing area (that is, the volume of mask 2 that is cured is the largest); the mask 2 in the middle layer, because of its photosensitivity
  • the sensitivity is greater than the sensitivity of the adjacent lower layer mask 2 but less than the adjacent upper layer mask 2, so that the curing degree and curing area of the middle layer mask 2 is greater than the adjacent next layer mask 2.
  • the film 2 is smaller than the adjacent previous layer mask 2; that is to say, from the surface of the cell 1 to the surface away from the cell 1, the cured area of the multi-layer mask 2 increases layer by layer, and the same layer of mask
  • the exposure points on 2 are set at intervals.
  • the curing areas formed by the two adjacent exposure points set at intervals do not overlap.
  • the two adjacent curing areas constitute an uncured area, which extends from the surface of the cell 1 to away from the cell. 1, the uncured area decreases layer by layer, forming a stepped development reaction area as shown in Figure 2-2.
  • a coordinate system is established with the surface of the cell 1 as the origin, the sensitivity is the dependent variable y, and the number of layers of the multi-layer mask 2 calculated upward from the surface of the cell 1 is the independent variable x.
  • the calculation formula of sensitivity y can be obtained y ⁇ ax n ⁇ b, a and n depend on the properties of mask 2, a is a positive number, mainly determined by mask 2
  • the photosensitive component and/or the concentration of the photosensitive component is determined. Theoretically, when n is 1, the cross-section of the development reaction area formed after exposure of the multi-layer mask 2 is roughly ladder-shaped. For example, reference can be made to the graphics in Figures 5-1 and 5-2.
  • a coordinate system is established with the surface of the cell 1 as the origin, the sensitivity is the dependent variable y, and the distance between the mask 2 and the surface of the cell 1 is the independent variable x, that is, the height of the mask 2 on the cell 1 is x.
  • the calculation formula of sensitivity y can be obtained y ⁇ ax n ⁇ b, a and n depend on the mask
  • the properties of 2, a being a positive number, are mainly determined by the photosensitive component and/or the concentration of the photosensitive component in the mask 2. Theoretically, when n is 1, the cross-section of the development reaction area formed after the mask 2 is exposed is roughly trapezoidal or triangular.
  • the following method is used to form a development reaction area with a width gradient: coating the surface of the cell sheet 1 to form a multi-layer mask 2, each layer of mask 2 has a different absorption peak; exposing the multi-layer mask In areas where openings are not required on the film 2, the degree of solidification of the multi-layer mask 2 increases layer by layer from the surface of the cell sheet to the surface away from the cell sheet 1, so as to form a development reaction area with a width gradient on the mask 2; Alternatively, the area on the multi-layer mask 2 that needs to be opened is exposed, so that the degree of solidification of the multi-layer mask 2 decreases layer by layer from the surface of the cell sheet 1 to the surface away from the cell sheet 1, so as to form a width gradient on the mask 2 development reaction zone.
  • a three-layer mask 2 is coated on the surface of the cell 1.
  • Each layer of the mask 2 has a different absorption peak, and a wavelength range of light is selected, for example, the wavelength band is 380nm- 410nm
  • the sensitivity of the three-layer mask 2 to the light in the selected wavelength range decreases layer by layer from the surface of the cell 1 to the surface away from the cell 1, that is, the layer (the bottom layer) of the mask close to the surface of the cell 1
  • Film 2 has the highest sensitivity to light in the selected waveband range.
  • the layer of mask 2 far away from the surface of cell 1 (the top layer) has the lowest sensitivity to light in the selected waveband range.
  • the layer of mask in the middle is the lowest. 2.
  • Its sensitivity to the light in the selected wave band range is smaller than the sensitivity of the adjacent lower layer mask 2 to the light in the selected wave band range but greater than the sensitivity of the adjacent upper layer mask 2 to the selected wave band range.
  • Light sensitivity Use the same beam of light to expose the three-layer masks at the same time, exposing the area that needs to be opened on the three-layer mask 2, and the exposure time is the same; among all the multi-layer masks 2, the bottom mask 2 is suitable for the selected wave band range has the highest sensitivity to light and absorbs the most energy of light, so that the bottom layer of mask 2 has the highest degree of curing and the largest curing area (that is, the volume of mask 2 that is cured is the largest); the top layer of mask 2 is selected The light in a certain waveband range has the lowest sensitivity and absorbs the least energy of light, so that the uppermost layer of mask 2 has the lowest degree of curing.
  • the curing area is the smallest (that is, the volume of the mask 2 that is cured is the smallest); the mask 2 located in the middle layer is less sensitive to the light in the selected wavelength range than the adjacent next layer of mask 2.
  • the sensitivity of the light in the band range is greater than the sensitivity of the adjacent upper layer mask 2 to the light in the selected band range, so that the curing degree and curing area of the mask 2 in the middle layer are smaller than that of the adjacent lower layer mask.
  • the film 2 is larger than the adjacent upper mask 2; that is to say, from the surface of the battery sheet 1 to the surface away from the battery sheet 1, the cured area decreases layer by layer, which forms the structure shown in Figure 1-2. Step-shaped development reaction zone.
  • a three-layer mask 2 is coated on the surface of the cell sheet 1.
  • Each layer of the mask 2 has a different absorption peak, and a wavelength range of light is selected, for example, the wavelength band is 380nm- 410nm
  • the sensitivity of the three-layer mask 2 to the light in the selected wavelength range increases layer by layer from the surface of the cell 1 to the surface away from the cell 1, that is, the layer (the bottom layer) of the mask close to the surface of the cell 1
  • Film 2 has the lowest sensitivity to light in the selected waveband range.
  • the layer of mask 2 far away from the surface of cell 1 (the top layer) has the highest sensitivity to light in the selected waveband range.
  • the layer of mask 2 in the middle is the most sensitive to light in the selected waveband range. , its sensitivity to the light in the selected wave band range is greater than the sensitivity of the adjacent lower layer mask 2 to the light in the selected wave band range but smaller than the sensitivity of the adjacent upper layer mask 2 to the light in the selected wave band range. sensitivity.
  • the bottom mask 2 is suitable for the selected wave band
  • the sensitivity of light in the range is the lowest and absorbs the least light energy, so that the bottom layer of mask 2 has the lowest degree of curing and the smallest curing area (that is, the volume of mask 2 that is cured is the least); the top layer of mask 2 pairs
  • the light in the selected waveband range has the highest sensitivity and absorbs the most energy of light, so that the uppermost layer of mask 2 has the highest degree of curing and the largest curing area (that is, the volume of mask 2 that is cured is the largest); the mask 2 located in the middle layer has the highest sensitivity.
  • Mask 2 because its sensitivity to the light in the selected band range is greater than the sensitivity of the adjacent lower layer mask 2 to the selected light range but less than the sensitivity of the adjacent upper layer mask 2 to the selected
  • the sensitivity of light in the wavelength range makes the curing degree and curing area of the mask 2 in the middle layer larger than the adjacent next layer mask 2 and smaller than the adjacent upper layer mask 2; that is to say, from the cell sheet
  • the surface of 1 is directed away from the surface of the cell 1, and the curing area of the multi-layer mask 2 increases layer by layer.
  • the exposure points on the same layer of mask 2 are set at intervals, and the two adjacent exposure points set at intervals form The cured areas do not overlap.
  • An uncured area is formed between two adjacent cured areas. From the surface of the cell 1 to the surface away from the cell 1, the uncured area decreases layer by layer, forming the structure shown in Figure 2-2.
  • the following method is used to form a development reaction area with a width gradient: a layer of mask 2 is formed on the surface of the cell sheet 1; the area on the mask 2 that does not require openings is exposed, and the focus position of the exposure is adjusted. And/or light intensity and/or wavelength, the mask 2 gradually absorbs the exposure energy from the surface of the cell 1 to the surface away from the cell 1, thereby causing the mask 2 to move from the surface of the cell 1 away from the cell. The degree of curing in the surface direction of sheet 1 is gradually increased to form a development reaction area with a width gradient on mask 2; or, the area on mask 2 that needs to be opened is exposed, and the focus position and/or light intensity of exposure are adjusted.
  • the absorption of exposure energy by the mask 2 gradually decreases from the surface of the battery sheet 1 to the surface direction away from the battery sheet 1, thereby causing the mask 2 to solidify from the surface of the battery sheet 1 to the surface direction away from the battery sheet 1
  • the degree is reduced layer by layer to form a development reaction area with a width gradient on the mask 2 .
  • a single-layer mask 2 is used, and the single-layer mask 2 is easy to prepare, which can reduce the production cost of the mask 2 .
  • a layer of mask 2 is formed on the surface of the battery sheet 1.
  • the mask 2 is divided into three virtual layers. From the surface of the battery sheet 1 to away from the battery sheet The surface direction of 1 is the first layer 21, the second layer 22 and the third layer 23 in sequence.
  • the three-layer mask 2 is exposed layer by layer from the surface of the cell 1 to the surface direction away from the cell 1.
  • the surface of the exposure mask 2 In the area that needs to be opened, the exposed light intensity decreases layer by layer from the surface of the cell 1 to the surface away from the cell 1, and the number of exposures at the same exposure point decreases layer by layer from the surface of the cell 1 to the surface away from the cell 1.
  • the exposure wavelength is lengthened layer by layer from the surface of the cell 1 to the surface away from the cell 1; the purpose is to make the The mask 2 of the layer (the bottom layer) on the surface of the cell 1 absorbs the most energy of light, the mask 2 of the layer (the top layer) far away from the surface of the cell 1 absorbs the least energy of the light, and the mask in the middle absorbs the least energy.
  • the bottom layer mask 2 absorbs light energy less than the energy absorbed by the adjacent lower layer mask 2 but greater than the energy absorbed by the adjacent upper layer mask 2; thus making the bottom layer mask 2 have the highest degree of curing, and the cured area
  • the largest that is, the volume of mask 2 that is cured is the largest
  • the top layer of mask 2 has the lowest degree of curing
  • the cured area is the smallest (that is, the volume of mask 2 that is cured is the least)
  • the middle layer of mask 2 has The degree of curing and the cured area are smaller than the adjacent next layer mask 2 and larger than the adjacent upper layer mask 2; that is to say, from the surface of the battery sheet 1 to the surface direction away from the battery sheet 1, the cured area is layer by layer. decreases, eventually forming a stepped development reaction zone as shown in Figure 3-4.
  • a layer of mask 2 is formed on the surface of the battery sheet 1.
  • the mask 2 is divided into three virtual layers. From the surface of the battery sheet 1 to away from the battery sheet The surface direction of 1 is the first layer 21, the second layer 22 and the third layer 23 in sequence.
  • the three-layer mask 2 is exposed layer by layer from the surface of the cell 1 to the surface direction away from the cell 1.
  • the surface of the exposure mask 2 In areas where openings are not required, the exposure light intensity increases layer by layer from the surface of the battery sheet 1 to the surface away from the battery sheet 1.
  • the number of exposures at the same exposure point is layer by layer from the surface of the battery sheet 1 to the surface away from the battery sheet 1.
  • the exposure wavelength shortens layer by layer from the surface of the cell 1 to the surface away from the cell 1; the purpose is to make the layer (the bottom layer) of the mask 2 close to the surface of the cell 1 absorb the least energy of light, and away from the surface of the cell 1
  • the mask 2 on the surface of the cell 1 absorbs the most light energy.
  • the mask 2 in the middle absorbs more light energy than the adjacent mask 2 on the next layer but less than the adjacent mask 2 .
  • the adjacent upper layer of mask 2 absorbs the energy of the light; thus the bottom layer of mask 2 has the lowest degree of curing and the smallest curing area (that is, the volume of mask 2 that is cured is the smallest), and the top layer of mask 2 has the smallest curing degree.
  • the curing degree is the highest and the curing area is the largest (that is, the volume of the mask 2 that is cured is the largest).
  • the curing degree and the curing area of the mask 2 in the middle layer are greater than the adjacent next layer mask 2 and smaller than the adjacent previous one.
  • Layer mask 2 that is to say, from the surface of the cell 1 to the surface away from the cell 1, the curing area of the multi-layer mask 2 increases layer by layer, and the exposure points on the same layer of mask 2 are set at intervals.
  • the cured areas formed by two adjacent exposure points arranged at intervals do not overlap, and an uncured area is formed between the two adjacent cured areas. From the surface of the battery sheet 1 to the direction away from the surface of the battery sheet 1, the uncured areas gradually The layers are reduced, eventually forming the stepped development reaction zone shown in Figure 4-4.
  • a layer of mask 2 is formed on the surface of the cell sheet 1, and the amount of light transmission (or light transmission capability) of the mask 2 decreases with the thickness of the light penetrating the mask 2; exposure mask 2 does not require openings in the area to form a development reaction area with a width gradient on the mask.
  • the mask 2 will continue to absorb and reflect the light, so that the light transmission amount of the mask 2 decreases with the thickness of the light penetrating the mask 2, and then the exposure amount increases from the surface of the cell 1 It increases layer by layer in the direction away from the surface of the cell 1, that is, the exposed area (cured area) increases layer by layer from the surface of the cell 1 to the direction away from the surface of the cell 1.
  • the unexposed area between the two exposed areas on the mask 2 The area (uncured area) constitutes a development reaction area with a width gradient.
  • the method for preparing gate lines includes the following steps: dividing the surface of the cell sheet 1 into a first area and a second area; forming a first mask on the first area.
  • Film 2a the first mask 2a can be a single layer or multiple layers, a second mask 2b is formed on the second area, the second mask 2b can be a single layer or multiple layers; according to the properties of the first mask 2a ( Positive resist or negative resist), expose a local area of the first mask 2a to form a first development reaction area with a width gradient on the first mask 2a;
  • the first mask 2a is developed to form a first mask opening 31 with a width gradient in the first development reaction area; a first metal is electroplated in the first mask opening 31 to form a first gate line with a width gradient.
  • a local area of the second mask 2b is exposed to form a second development reaction area with a width gradient on the second mask 2b;
  • the mask 2b is developed to form a second development reaction zone A second mask opening 32 having a width gradient;
  • a second metal is electroplated in the second mask opening 32 to form a second gate line 42 having a width gradient.
  • the first metal and the second metal may be the same metal or different metals.
  • the first area and the second area are both located on the same surface of the battery sheet 1, or the first area and the second area are located on two surfaces of the battery sheet 1, or the first area is provided on both surfaces of the battery sheet 1. area and second area.
  • the first mask 2a is a single layer, for convenience of description, the first mask 2a is divided into three virtual layers. From the surface of the cell sheet 1 to the surface away from the cell sheet 1, the first mask layer and the first layer are sequentially 2a1, the second layer of the first mask 2a2 and the third layer of the first mask 2a3, with reference to the foregoing embodiments, can be controlled by controlling the sensitivity and/or absorption peak of each layer of the first mask 2a, or by controlling the Exposure parameters on each layer of a mask 2a, such as exposure focus position, number of exposures at the same exposure point, exposure light intensity or wavelength, to obtain a first development reaction area with a width gradient. In the same way, the second mask 2b is divided into three virtual layers.
  • the third layer 2b3 of the second mask can be controlled by controlling the sensitivity and/or absorption peak of each layer of the second mask 2b, or by controlling the exposure parameters on each layer of the second mask 2b. , such as the focus position of exposure, the number of exposures at the same exposure point, the exposure light intensity or wavelength, to obtain a second development reaction area with a width gradient.
  • the technical means applied to the single-layer mask 2 can also be used to form a development reaction area with a width gradient.
  • the battery sheet 1 may have an IBC structure.
  • the first area and the second area are both located on the same surface of the battery sheet 1 (for example, on the front), and the first mask 2a is formed on the first area.
  • forming a second mask 2b on the second area exposing the opening area of the first mask 2a to form a first development reaction area with a width gradient on the first mask 2a; facing the first development reaction area
  • the first mask 2a in the first development reaction area is developed to form a first mask opening 31 with a width gradient in the first development reaction area; a first metal is electroplated in the first mask opening 31 to form a first mask opening 31 with a width gradient.
  • Grid line 41 is
  • the opening area of the second mask 2b is exposed to form a second development reaction area with a width gradient on the second mask 2b; the second mask 2b located in the second development reaction area is developed to form a second development reaction area on the second mask 2b.
  • the second development reaction area forms a second mask opening 32 with a width gradient; a second metal is electroplated in the second mask opening 32 to form a second gate line 42 with a width gradient.
  • the first metal and the second metal may be the same metal or different metals.
  • the first metal and the second metal are respectively selected from silver, copper, aluminum, magnesium, chromium, nickel, molybdenum, tin, titanium, tungsten, or an alloy or laminate composed of any two or more of the above.
  • forming the first mask 2a on the first area and forming the second mask 2b on the second area can be performed simultaneously, and then the first mask opening 31 is completed and the second mask 2b is formed on the second area.
  • the first metal is electroplated in the first mask opening 31
  • the second mask opening 32 is completed and the second metal is electroplated in the second mask opening 32 .
  • first mask opening 31 and the second mask opening 32 are completed at the same time, when the first metal is electroplated in the first mask opening 31, if the second mask opening 32 is not protected, in the second mask opening 32
  • the first metal is also electroplated, and the first mask opening 31 is first completed and the first metal is electroplated in the first mask opening 31, and then the second mask opening 32 is completed and the second metal is electroplated in the second mask opening 32.
  • Metal when the first metal is electroplated, the second mask opening 32 does not yet exist, so the first metal will not be electroplated in the second mask opening 32 .
  • the surface of the first metal (first gate line 41) located in the first mask opening 31 may also be electroplated with the second metal; if the process If necessary, the surface of the first gate line 41 can be electroplated with a second metal. That is, the first gate line 41 has a metal stack structure, and the second gate line 42 has a single metal.
  • the first metal is copper and the second metal is tin. Copper is easily oxidized, so you can continue to electroplat tin on the surface of copper; if you need to avoid electroplating the second metal on the surface of the first gate line 41, you can pre-coat the surface of the first gate line 41 before electroplating the second metal.
  • Cloth protective layer such as coating mask 2.
  • the mask material is coated on the side of the battery sheet 1, so that the mask material solidifies to form the mask 2.
  • electroplating metal in the mask opening 3 it can be avoided: electroplating metal on the side of the battery sheet 1, As a result, the front and back sides of the cell 1 are electrically connected, affecting the efficiency of the cell 1 .
  • a local area of the mask 2 is exposed to form a development on the mask 2 with a trapezoidal or stepped longitudinal cross-section.
  • Reaction zone develop the mask 2 located in the development reaction zone to form a mask opening 3 with a trapezoidal or stepped longitudinal cross-section in the development reaction zone; electroplating metal in the mask opening 3 to form a trapezoidal or stepped longitudinal cross-section.
  • the grid line 4 with a width gradient includes a grid line 4 with a triangular or trapezoidal or stepped longitudinal section.
  • the grid line 4 with a trapezoidal or stepped longitudinal section is easily formed directly by electroplating, or can be formed by covering the surface of the grid line 4 with reflection.
  • the alloy welding layer or organic protective layer with a melting point lower than 300°C makes the longitudinal cross-section of the grid line 4 form a triangle or a trapezoid, that is, the preparation process of the grid line 4 with a triangular, trapezoidal or ladder-shaped longitudinal section is simple.
  • the longitudinal section of the mask opening 3 is a trapezoid, and the base angle of the trapezoid is 45-89 degrees, so that a grid line 4 with a trapezoidal longitudinal section can be obtained by electroplating in the mask opening 3.
  • the longitudinal section of the trapezoidal grid line 4 is The bottom angle is 45-89 degrees, which can balance the conductive performance of the gate line 4 and make the gate line 4 have the best antireflection effect.
  • the base and height of the trapezoid are fixed, the larger the base angle of the trapezoid, the larger the area of the trapezoid (the area of the longitudinal section of the grid line 4), and the larger the volume of the grid line 4.
  • shapes such as triangles, trapezoids, or ladders mentioned in this application refer to the approximate shapes of triangles, trapezoids, or ladders that the object forms when viewed as a whole. When observed at a micro scale, these shapes The edges of may not be straight lines, and the corners of these shapes may not be the intersection of two straight lines. It is understandable that industrial products cannot be produced with geometric shapes, and the description of the geometric shape of any industrial product is an approximate description.
  • a dielectric layer is provided on the cell sheet 1. After the mask opening 3 with a width gradient is formed in the development reaction area, the dielectric layer directly below the mask opening 3 is removed. Laser removal or chemical etching can be used to remove it. , so that the mask opening 3 is connected to the conductive structural layer of the cell 1, such as the seed layer, the TCO layer or the semiconductor doping layer, thereby allowing the metal to be smoothly electroplated onto the conductive structural layer to form the gate line 4.
  • the gate lines 4 with a width gradient can also be in other shapes that meet the definition of the width gradient.
  • Figure 5 exemplarily shows some grid lines with a width gradient. Schematic diagram of the longitudinal section of the gate line 4.
  • the gate line 4 is divided into four layers distributed from top to bottom, namely the first layer 4a, the second layer 4b, and the third layer 4c.
  • the fourth layer 4d where the first layer 4a is the top layer, the fourth layer 4d is the bottom layer, the width of the second layer 4b is greater than the width of the first layer 4a, and the width of the third layer 4c is greater than the width of the second layer 4b and the first layer 4d.
  • the width of the layer 4a and the width of the fourth layer 4d are greater than the widths of the third layer 4c, the second layer 4b and the first layer 4a.
  • the second layer 4b and the third layer 4c here are , the fourth layer 4d are all width expansion layers.
  • the difference between these five sub-embodiments mainly lies in the shape of each layer, as follows:
  • both sides of the longitudinal section of each layer of the grid line 4 are straight lines extending in the vertical direction. That is to say, each side of the grid line 4 in the up and down direction
  • the longitudinal section of the layer is rectangular or square, and the entire longitudinal section of the grid line 4 is stepped.
  • both sides of the longitudinal section of each layer of the gate line 4 are oblique lines extending obliquely in the up and down direction.
  • the oblique lines extend from top to bottom.
  • the outer part gradually extends obliquely, so that the longitudinal section of each floor is a trapezoid with a narrow top and a wide bottom.
  • the upper and lower edges of all layers of the gate line 4 In any two adjacent layers, the maximum width of the upper layer is smaller than the minimum width of the lower layer.
  • the width value of the bottom part of the first layer 4a is smaller than the width value of the top part of the second layer 4b
  • the width value of the bottom part of the second layer 4b is
  • the width value of the uppermost part of the third layer 4c is smaller than the width value of the uppermost part of the third layer 4c
  • the width value of the lowermost part of the third layer 4c is also smaller than the width value of the uppermost part of the fourth layer 4d.
  • the two sides of the longitudinal section of some layers are straight lines extending in the vertical direction, and the longitudinal sections of these layers are rectangular or square. Specifically, they are the first layer 4a and the third layer 4c; the two sides of the longitudinal section of other layers are diagonal lines that gradually extend outward from top to bottom.
  • the longitudinal sections of these layers are trapezoidal, specifically here It is the 2nd floor 4b and the 4th floor 4d.
  • the width value of the first layer 4a is smaller than the minimum width value of the second layer 4b
  • the maximum width value of the second layer 4b is smaller than the width value of the third layer 4c
  • the width value of the third layer 4c is smaller than the minimum width value of the fourth layer 4d. Width value.
  • both sides of the longitudinal section of each layer are arcs extending in the up and down direction.
  • the arcs are from the top
  • the arc that arches inward from the bottom to the bottom makes the longitudinal section of each floor look like a trapezoid with curved edges.
  • an arc-sided trapezoid refers to a figure formed by replacing at least one of the two waist sides of the trapezoid with an arc.
  • the two sides of the longitudinal section of the first layer 4a of the gate line 4 are oblique lines that gradually extend outward in the up and down direction.
  • the longitudinal section of the first layer 4a is a trapezoid; the two sides of the longitudinal section of the second layer 4b are straight lines extending in the vertical direction, and the longitudinal section of the second layer 4b is rectangular or square; the two sides of the longitudinal section of the third layer 4c are An arc extending in the up and down direction.
  • the arc here is specifically an arc that arches outward from top to bottom.
  • the longitudinal section of the third layer 4c is a trapezoid with arc edges; the two sides of the longitudinal section of the fourth layer 4d The sides are oblique lines extending gradually outward in the up-down direction, and the longitudinal section of the fourth layer 4d is trapezoidal.
  • the width value of the bottom part of the first layer 4a is smaller than the width value of the second layer 4b
  • the width value of the second layer 4b is smaller than the width value of the top part of the third layer 4c
  • the width value of the bottom part of the third layer 4c is smaller than the width value of the fourth layer 4c.
  • the width value of the uppermost part of layer 4d is a trapezoid with arc edges; the two sides of the longitudinal section of the fourth layer 4d The sides are oblique lines extending gradually outward in the up-down direction, and the longitudinal section of the fourth layer 4d is trapezoidal.
  • the width value of the bottom part of the first layer 4a is smaller than the width value of the second layer 4b
  • the main difference between the sixth sub-embodiment shown in Figure 5-6 and the five sub-embodiments shown in Figures 5-1 to 5-5 is that in this sub-embodiment, the width of the second layer 4b and the fourth layer 4d is expanded. layer. Specifically: the longitudinal sections of the first layer 4a, the second layer 4b, the third layer 4c, and the fourth layer 4d are all trapezoidal, and the two sides of the longitudinal section of each layer extend gradually outward and obliquely in the up and down direction. slash.
  • the width of the second layer 4b is greater than the width of the first layer 4a; the width of the third layer 4c is less than the width of the second layer 4b; the width of the fourth layer 4d is greater than the width of the third layer 4c and greater than the width of the second layer 4b and the first layer 4b.
  • the second layer 4b is one width-enlarged layer relative to the first layer 4a
  • the fourth layer 4d is another width-enlarged layer relative to the first layer 4a, the second layer 4b, and the third layer 4c.
  • the longitudinal section of the grid line 4 is an arc-edged triangle, and the width of the grid line 4 increases from top to bottom.
  • the longitudinal section includes a bottom
  • the side L0, the side L1, and the side L2 are both arcs.
  • both the side L1 and the side L2 are arcs arching inward from top to bottom; in the eighth sub-embodiment shown in Figures 5-8 , both side L1 and side L2 are arcs that arch outward from top to bottom; in the ninth sub-embodiment shown in Figure 5-9, one side L1 is an arc that arches outward from top to bottom. Arc, the other side L2 is an arc that arches inward from top to bottom.
  • the longitudinal section of the grid line 4 is a trapezoid with arc edges, and the width of the grid line 4 increases sequentially from top to bottom.
  • the longitudinal section includes a bottom The side L0, the top side L3, the side L1, and the side L2, where both the side L1 and the side L2 are arcs.
  • both the side L1 and the side L2 are arcs arching inward from top to bottom; in the eleventh sub-embodiment shown in Figures 5-11
  • one side L1 is an arc that arches outward from top to bottom.
  • the other side L2 is an arc that arches inward from top to bottom.
  • the shape of the longitudinal section of the gate line 4 with the width gradient is not limited to the above example. Electroplating preparation
  • the gate line 4 and the mask opening 3 are similar to the mold of the gate line 4.
  • the shape of the gate line 4 is determined by the shape of the mask opening 3. Therefore, the shape of the longitudinal section of the development reaction area and the shape of the longitudinal section of the gate line 4
  • the shape of the longitudinal section of the mask opening 3 is the same as the shape of the longitudinal section of the gate line 4 , that is, the shape of the longitudinal section of the development reaction area and the shape of the longitudinal section of the mask opening 3 can refer to the example in FIG. 5 .
  • the longitudinal section of the grid line refers to the cross section where a plane perpendicular to the extension direction of the length of the grid line intersects with the grid line.
  • the photovoltaic component includes a photovoltaic cell and an encapsulation layer, and the photovoltaic cell includes at least one cell sheet 1 and a grid line 4 thereon.
  • the mask 2 has multiple layers, preferably 2 to 10 layers, and more preferably 3 to 5 layers. If the number of mask layers is too small, the mask opening 3 with a width gradient cannot be well prepared; if the number of mask layers is too many, the preparation process and the equipment for implementing the process will be more complicated, which will increase the preparation cost. Efficiency is reduced.
  • all the mask openings 3 are joined together in the up and down direction so that their longitudinal sections form a trapezoid or step shape, preferably an isosceles trapezoid, which can be formed after electroplating Correspondingly shaped gate lines 4 with gradient width.
  • photo-induced cross-linking or polymerization or decomposition is used to generate a development reaction zone with a width gradient, and a smaller width of the development reaction zone can be obtained; a smaller width of the mask opening 3 can be obtained through development.
  • Electroplating metal in the film opening 3 can obtain a gate line 4 with a smaller line width.
  • the line width w of the gate line 4 can reach 5 microns ⁇ w ⁇ 50 microns, preferably 5 microns ⁇ w ⁇ 20 microns or 20 microns ⁇ w ⁇ 40 micron, more preferably 5 micron ⁇ w ⁇ 10 micron.
  • the line width w of the grid lines 4 is generally 50 microns ⁇ w ⁇ 200 microns.
  • the line width of the gate line 4 formed in the foregoing embodiment is lower than the line width of the gate line 4 in the prior art, which reduces the light-shielding area of the gate line 4 and is beneficial to improving the photoelectric conversion efficiency of the cell sheet 1 .
  • Embodiments of the present invention also provide a method for preparing a battery sheet.
  • the grid lines 4 on the battery sheet 1 are prepared using the following steps:
  • Embodiments of the present invention also provide a photovoltaic cell.
  • the photovoltaic cell includes a cell sheet 1 and a grid line 4 with a gradient width arranged on the cell sheet 1.
  • the grid line 4 with a gradient width has an antireflection effect and can increase photovoltaic power. The power generation efficiency of the battery.
  • the gate line 4 with gradient width can be prepared according to the aforementioned gate line preparation method.
  • the longitudinal section of the gate line 4 is triangular, trapezoidal, or stepped.
  • the surface of the grid line 4 is also covered with a reflective layer of bright tin or bright silver; or the surface of the grid line 4 is covered with an alloy solder layer with a melting point lower than 300°C.
  • the alloy solder layer is made of tin, lead, and bismuth. , silver, copper, One or more of indium and zinc are formed; or the surface of the gate line 4 is covered with an organic protective layer.
  • grid lines 4 are provided on at least the light-receiving surface of the cell sheet, or grid lines 4 are provided on both sides of the cell sheet.
  • the materials of the multiple grid lines 4 located on the same surface of the battery sheet are different metals and/or the materials of the multiple grid lines 4 located on different surfaces of the battery sheet are different metals.
  • the material of the gate line 4 may be selected from silver, copper, aluminum, magnesium, chromium, nickel, molybdenum, tin, titanium, tungsten, or an alloy or laminate composed of any two or more of the above.
  • multiple grid lines 4 are provided on the front or back surface of the battery sheet.
  • the front or back surface of the battery sheet is divided into area A and area B.
  • the grid lines 4 located in area A are of the first metal
  • the grid lines 4 located in area B are of the first metal.
  • the gate line 4 is made of a second metal; preferably, the first metal is silver or copper, and the second metal is aluminum.
  • grid lines 4 are provided on both the front and back surfaces of the battery sheet.
  • the grid lines 4 on the front side of the battery sheet are all made of the first metal, and the grid lines 4 on the back side of the battery sheet are all made of the second metal; the first The first metal is silver or copper, and the second metal is aluminum.
  • multiple grid lines 4 are provided on both the front and back surfaces of the cell sheet.
  • the front side of the cell sheet is divided into area A and area B.
  • the grid lines 4 located in area A are the first metal
  • the grid lines 4 located in area B are of the first metal.
  • the wires 4 are made of the second metal; the grid lines 4 on the reverse side of the cell are all made of the first metal or the second metal or the third metal; preferably, the first metal is silver or copper, and the second metal is Aluminum, the third metal is nickel.
  • multiple grid lines 4 are provided on both the front and back surfaces of the cell sheet.
  • the front side of the cell sheet is divided into area A and area B.
  • the grid lines 4 located in area A are the first metal, and the grid lines 4 located in area B are of the first metal.
  • Line 4 is the second metal; the back side of the cell is divided into C area and D area.
  • the grid line 4 in the C area is the first metal or the second metal, and the grid line 4 in the D area is the third metal.
  • Metal preferably, the first metal is silver or copper, the second metal is aluminum, and the third metal is nickel.
  • multiple grid lines 4 are provided on both the front and back surfaces of the cell sheet.
  • the front side of the cell sheet is divided into area A and area B.
  • the grid lines 4 located in area A are the first metal, and the grid lines 4 located in area B are of the first metal.
  • Line 4 is the second metal;
  • the back side of the cell is divided into C area and D area, where the grid line 4 located in the C area is the third metal, and the grid line 4 located in the D area is the fourth metal;
  • the first metal is a stack of tin-plated copper
  • the second metal is aluminum
  • the third metal is nickel
  • the fourth metal is tin.
  • the minimum line width of the gate lines is less than 50 microns and greater than or equal to 10 microns, which is lower than the line width of the gate lines 4 in the prior art. This reduces the light-shielding area of the gate lines 4 and can improve the cell 1 photoelectric conversion efficiency.
  • three groups of 210 mm ⁇ 105 mm heterojunction bifacial cells T1, T2 and T3 were selected for testing. Each group included 20 cells, all using single-sided illumination, and the grid line material was copper. Except for the table Except for the factors listed in , other parameters of the cell remain the same, and the test results are shown in Table 1.
  • the short-circuit current and efficiency are the average values of 20 cells.
  • the product of the fine gate line width and the number of fine gates is called the total line width.
  • the ratio of the short-circuit current to the total line width is called the line width current.
  • the ratio of efficiency to the total line width called linewidth efficiency.
  • the thinner the gate line the greater the short-circuit current, the higher the efficiency, the greater the line width current, and the higher the line width efficiency, that is, the thin gate Wires can improve the efficiency of battery cells.
  • the fine gate line width and the number of fine gates in the T3 group are different from those of the T1 and T2 groups.
  • the concept of total line width is introduced. The total line width can reflect the shielding of the battery by all gate lines.
  • Each group included 20 cells, all using single-sided illumination, and the grid line material was copper. All cells The grid lines are formed by electroplating using the electroplating method in the embodiments of the present application. Except for the factors listed in the table, other parameters of the cells remain the same. The test results are shown in Table 2.

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Abstract

本发明公开了一种栅线的制备方法、电池片的制备方法及光伏电池，其中，栅线的制备方法包括如下步骤：在电池片的正面和/或反面涂布掩膜材料，使得掩膜材料固化形成掩膜；根据掩膜的性质，对掩膜的局部区域进行曝光，以在掩膜上形成具有宽度梯度的显影反应区；对位于显影反应区的掩膜进行显影，以在显影反应区形成具有宽度梯度的掩膜开口；在掩膜开口中电镀金属，以形成具有宽度梯度的栅线；去除掩膜。通过本发明实施例的栅线的制备方法，可以在电池片上形成具有宽度梯度的栅线，该具有宽度梯度的栅线被封装到光伏组件中以后，可以增加发电效率。

Description

一种栅线的制备方法、电池片的制备方法及光伏电池 技术领域
本发明涉及光伏电池制造领域，具体涉及一种栅线的制备方法、电池片的制备方法及光伏电池。
背景技术
光伏电池的栅线采用丝网印刷银浆的方式制备时，银浆在透过网版预制的开孔后转移到基板上形成未凝固的栅线，在网版与基板分离时，未凝固的栅线与网版纱线接触处被拉抬，网版与基板分离后，未凝固的栅线有一定的流平性，导致最终成形的栅线的纵截面呈下宽上窄的类似半圆弧的形状，称为圆弧形栅线。这样的圆弧形栅线在封装到组件中以后，具有对入射光多角度反射的作用，而这种反射，有一定的几率在组件内部的材料界面上再次反射回电池片表面，从而增加发电效率(光电转化效率)，这种现象称为增反效果。
为了进一步降低光伏电池成本和提升电池效率，使用铜电镀取代丝网印刷银浆制作光伏电池的栅线正在得到越来越多的关注和研究。而当采用铜电镀工艺取代银浆印刷工艺制备栅线时，铜电镀的掩膜开口通常是矩形或近似矩形，使得成形的栅线的纵截面为矩形或近似矩形，称为矩形栅线。然而矩形栅线无法增加栅线表面向各个方向的反射，因此在组件封装后会产生超过圆弧形栅线的封装损失，进而影响发电效率和生命周期内的发电量。圆弧形栅线的增反效果，用栅线的光学宽度来表征，通常为其物理最宽处的宽度的70％；矩形栅线的光学宽度通常为其物理最宽处的宽度的90％以上。
因此，本发明提出一种栅线的制备方法、电池片的制备方法及光伏电池，缩小栅线的光学宽度以提升光伏电池的光电转化效率。
以上背景技术内容的公开仅用于辅助理解本专利申请的发明构思及技术方案，其并不必然属于本专利申请的现有技术，在没有明确的证据表明上述内容在本专利申请的申请日之前已经公开的情况下，上述背景技术不应当用于评价本申请的新颖性和创造性。
发明内容
本发明的一个目的是提供一种栅线的制备方法，缩小栅线的光学宽度以提升光伏电池的光电转化效率。
为达到上述目的，本发明的实施例提供一种栅线的制备方法，包括：
S1、在电池片的正面和/或反面涂布掩膜材料，使得所述掩膜材料固化形成掩膜；
S2、根据所述掩膜的性质，对所述掩膜的局部区域进行曝光，以在所述掩膜上形成具有宽度梯度的显影反应区；
S3、对位于所述显影反应区的所述掩膜进行显影，以在所述显影反应区形成具有宽度梯度的掩膜开口；
S4、在所述掩膜开口中电镀金属，以形成具有宽度梯度的栅线；
S5、去除所述掩膜。
在一些实施例中，栅线的制备方法还包括：
步骤S6、在所述栅线表面覆盖反射层或熔点低于300℃的合金焊层或者有 机保护层；
其中，所述步骤S6设置在所述步骤S4之后且在所述步骤S5之前，或者所述步骤S6设置在所述步骤S5之后。
在一些实施例中，对所述电池片的双面涂布所述掩膜材料，至少在所述电池片的受光面形成所述具有宽度梯度的栅线；当所述电池片的结构为双面发电结构时，在所述电池片的双面上均形成所述具有宽度梯度的栅线。
在一些实施例中，前述步骤S2包括：曝光所述掩膜上不需要开口的区域，使得所述掩膜自所述电池片的表面向远离电池片的表面方向固化程度逐渐升高，以在所述掩膜上形成具有宽度梯度的显影反应区；或者，曝光所述掩膜上需要开口的区域，使得所述掩膜自所述电池片的表面向远离电池片的表面方向固化程度逐渐降低，以在所述掩膜上形成所述具有宽度梯度的显影反应区；所述步骤S3包括：根据所述掩膜自所述电池片的表面向远离电池片的表面方向固化程度逐渐升高或者逐渐降低的情形，选择相应的显影剂与所述具有宽度梯度的显影反应区中的掩膜发生显影反应，以形成所述具有宽度梯度的掩膜开口。
在一些实施例中，栅线的制备方法包括如下步骤：
S11、在所述电池片的表面上涂布形成多层所述掩膜，每一层所述掩膜具有不同的感光度；
S21、曝光多层所述掩膜上不需要开口的区域，使得多层所述掩膜自所述电池片的表面向远离电池片的表面方向固化程度逐层升高，以在所述掩膜上形成具有宽度梯度的显影反应区；或者，曝光多层所述掩膜上需要开口的区域，使得多层所述掩膜自所述电池片的表面向远离电池片的表面方向固化程度逐层降低，以在所述掩膜上形成所述具有宽度梯度的显影反应区；
其中，调整光敏组分和/或光敏成分的浓度以形成不同感光度的多层所述掩膜；
或者，
S12、在所述电池片的表面上涂布形成多层所述掩膜，每一层所述掩膜具有不同的吸收峰值；
S22、曝光多层所述掩膜上不需要开口的区域，使得多层所述掩膜自所述电池片的表面向远离电池片的表面方向固化程度逐层升高，以在所述掩膜上形成具有宽度梯度的显影反应区；或者，曝光多层所述掩膜上需要开口的区域，使得多层所述掩膜自所述电池片的表面向远离电池片的表面方向固化程度逐层降低，以在所述掩膜上形成所述具有宽度梯度的显影反应区；
或者，
S13、在所述电池片的表面上涂布形成一层所述掩膜；
S23、曝光所述掩膜上不需要开口的区域，调整曝光的焦点位置和/或光强和/或波长，使得所述掩膜自所述电池片的表面向远离电池片的表面方向对曝光能量的吸收逐渐增多，以在所述掩膜上形成具有宽度梯度的显影反应区；或者，曝光所述掩膜上需要开口的区域，调整曝光的焦点位置和/或光强和/或波长，使得所述掩膜自所述电池片的表面向远离电池片的表面方向对曝光能量的吸收逐渐减少，以在所述掩膜上形成所述具有宽度梯度的显影反应区。
或者，
S14、在所述电池片的表面上涂布形成一层所述掩膜，所述掩膜的透光量随光线穿透所述掩膜的厚度值递减；
S24、曝光所述掩膜上不需要开口的区域，以在所述掩膜上形成具有宽度梯度的显影反应区。
在一些实施例中，栅线的制备方法包括如下步骤：
将所述电池片的表面被划分为第一区域和第二区域；
在第一区域上形成第一掩膜，在第二区域上形成第二掩膜；
根据所述第一掩膜的性质，对所述第一掩膜的局部区域进行曝光，以在所述第一掩膜上形成具有宽度梯度的第一显影反应区；
对位于所述第一显影反应区的所述第一掩膜进行显影，以在所述第一显影反应区形成具有宽度梯度的第一掩膜开口；
在所述第一掩膜开口中电镀第一金属，以形成具有宽度梯度的第一栅线；
根据所述第二掩膜的性质，对所述第二掩膜的局部区域进行曝光，以在所述第二掩膜上形成具有宽度梯度的第二显影反应区；
对位于所述第二显影反应区的所述第二掩膜进行显影，以在所述第二显影反应区形成具有宽度梯度的第二掩膜开口；
在所述第二掩膜开口中电镀第二金属，以形成具有宽度梯度的第二栅线；
其中，所述第一金属和所述第二金属可以为相同的金属或者不同的金属；
所述第一区域和所述第二区域均位于电池片的同一面上，或者所述第一区域和所述第二区域分别位于电池片的两个面上。
在一些实施例中，在电池片的侧面涂布掩膜材料，使得所述掩膜材料固化形成掩膜。
在一些实施例中，根据所述掩膜的性质，对所述掩膜的局部区域进行曝光，以在所述掩膜上形成纵截面为梯形或阶梯形的显影反应区；
对位于所述显影反应区的所述掩膜进行显影，以在所述显影反应区形成纵截面为梯形或阶梯形的掩膜开口；
在所述掩膜开口中电镀金属，以形成纵截面为梯形或阶梯形的栅线。
在一些实施例中，所述掩膜开口的纵截面为梯形，所述梯形的底角为45-89度。
在一些实施例中，若在所述掩膜开口中电镀金属，未能形成纵截面为三角形或梯形的栅线；在所述栅线表面覆盖反射层或熔点低于300℃的合金焊层或者有机保护层，使得栅线的纵截面形成为三角形或梯形。
本发明的另一目的是提供一种电池片的制备方法，所述电池片上的栅线采用以下步骤制备：
S1、在电池片的正面和/或反面涂布掩膜材料，使得所述掩膜材料固化形成掩膜；
S2、根据所述掩膜的性质，对所述掩膜的局部区域进行曝光，以在所述掩膜上形成具有宽度梯度的显影反应区；
S3、对位于所述显影反应区的所述掩膜进行显影，以在所述显影反应区形成具有宽度梯度的掩膜开口；
S4、在所述掩膜开口中电镀金属，以形成具有宽度梯度的栅线；
S5、去除所述掩膜。
本发明的再一目的是提供一种光伏电池，包括具有宽度梯度的栅线，能够缩小栅线的光学宽度。
为达到上述目的，本发明实施例中采用的技术方案是：一种光伏电池，所述光伏电池包括电池片，以及设置在所述电池片上具有宽度梯度的栅线。
在一些实施例中，所述栅线的纵截面呈三角形或梯形或阶梯形。
在一些实施例中，所述栅线的表面还覆盖有亮锡或者亮银的反射层；或者
所述栅线的表面覆盖有熔点低于300℃的合金焊层，所述合金焊层为锡与铅、铋、银、铜、铟和锌中的一种或几种形成；或者
所述栅线的表面覆盖有有机保护层。
在一些实施例中，所述电池片的至少受光面设置有所述的栅线，或者所述电池片的两面均设置有所述的栅线。
在一些实施例中，所述栅线为多根，位于电池片同一面上的多根所述栅线的材料为不同金属和/或位于电池片不同面上的多根所述栅线的材料为不同金属。
在一些实施例中，所述栅线的最小线宽小于50微米且大于或等于5微米。
由于上述技术方案的运用，本发明的实施例与现有技术相比具有下列优点：通过本发明实施例的栅线的制备方法，可以在电池片上形成具有宽度梯度的栅线，该具有宽度梯度的栅线被封装到光伏组件中以后，具有对入射光多角度反射的作用；而这种反射作用，能够在光伏组件内部的材料界面上再次反射回电池片表面，从而增加发电效率。本发明实施例中的栅线的制备方法，工艺简单，便于进行大规模工业应用。
附图说明
附图1为本发明第一实施例中栅线的制备方法流程示意图；
附图1-1为本发明第一实施例中曝光掩膜的光照示意图；
附图1-2为本发明第一实施例中具有宽度梯度的显影反应区的示意图；
附图1-3为本发明第一实施例中具有宽度梯度的掩膜开口的示意图；
附图1-4为本发明第一实施例中具有宽度梯度的栅线的示意图；
附图1-5为本发明第一实施例中去除掩膜后电池片的示意图；
附图1-6为本发明第一实施例中栅线表面覆膜后的示意图；
附图2为本发明第二实施例中栅线的制备方法流程示意图；
附图2-1为本发明第二实施例中曝光掩膜的光照示意图；
附图2-2为本发明第二实施例中具有宽度梯度的显影反应区的示意图；
附图2-3为本发明第二实施例中具有宽度梯度的掩膜开口的示意图；
附图2-4为本发明第二实施例中具有宽度梯度的栅线的示意图；
附图2-5为本发明第二实施例中覆膜间隙的示意图；
附图2-6为本发明第二实施例中栅线表面覆膜后的示意图；
附图2-7为本发明第二实施例中去除掩膜后电池片的示意图；
附图3为本发明第三实施例中显影反应区的制备方法流程示意图；
附图3-1为本发明第三实施例中覆盖掩膜的电池片结构示意图；
附图3-2为本发明第三实施例中第一次曝光结果的示意图；
附图3-3为本发明第三实施例中第二次曝光结果的示意图；
附图3-4为本发明第三实施例中第三次曝光结果的示意图；
附图4为本发明第四实施例中显影反应区的制备方法流程示意图；
附图4-1为本发明第四实施例中覆盖掩膜的电池片结构示意图；
附图4-2为本发明第四实施例中第一次曝光结果的示意图；
附图4-3为本发明第四实施例中第二次曝光结果的示意图；
附图4-4为本发明第四实施例中第三次曝光结果的示意图；
附图5为本发明第五实施例中具有宽度梯度的栅线的纵截面的示意图；
附图6为本发明第六实施例中栅线的制备方法流程示意图；
附图6-1为本发明第六实施例中覆盖掩膜的电池片结构示意图；
附图6-2为本发明第六实施例中对第一掩膜曝光结果的示意图；
附图6-3为本发明第六实施例中第一掩膜上的第一掩膜开口示意图；
附图6-4为本发明第六实施例中第一掩膜上的第一栅线示意图；
附图6-5为本发明第六实施例中对第二掩膜曝光结果的示意图；
附图6-6为本发明第六实施例中第二掩膜上的第二掩膜开口示意图；
附图6-7为本发明第六实施例中第二掩膜上的第二栅线示意图；
附图6-8为本发明第六实施例中去除掩膜后的电池片结构示意图；
附图7为本发明第七实施例中栅线的制备方法流程示意图；
附图7-1为本发明第七实施例中覆盖掩膜的电池片结构示意图；
附图7-2为本发明第七实施例中对第一掩膜曝光结果的示意图；
附图7-3为本发明第七实施例中第一掩膜上的第一掩膜开口示意图；
附图7-4为本发明第七实施例中第一掩膜上的第一栅线示意图；
附图7-5为本发明第七实施例中对第二掩膜曝光结果的示意图；
附图7-6为本发明第七实施例中第二掩膜上的第二掩膜开口示意图；
附图7-7为本发明第七实施例中第二掩膜上的第二栅线示意图；
附图7-8为本发明第七实施例中去除掩膜后的电池片结构示意图；
其中：1、电池片；2、掩膜；21、第一层；22、第二层；23、第三层；2a1、第一掩膜第一层；2a2、第一掩膜第二层；2a3、第一掩膜第三层；2b 1、第二掩膜第一层；2b2、第二掩膜第二层；2b3、第二掩膜第三层；3、掩膜开口；4、栅线；4a、第1层(顶层)；4b、第2层；4c、第3层；4d、第4层；L0、底边；L1、侧边；L2、侧边；L3、顶边；5、覆盖层。
具体实施方式
光伏电池的栅线采用丝网印刷银浆的方式制备。银浆在透过网版预制的开孔后转移到基板上形成未凝固的栅线，在网版与基板分离时，未凝固的栅线与网版纱线接触处被拉抬，网版与基板分离后，未凝固的栅线有一定的流平性，导致最终成形的栅线的纵截面呈下宽上窄的类似半圆弧的形状，称为圆弧形栅线。这样的圆弧形栅线在封装到组件中以后，具有对入射光多角度反射的作用，而这种反射，有一定的几率在组件内部的材料界面上再次反射回电池片表面，从而增加发电效率(光电转化效率)，这种现象称为增反效果。
为了进一步降低光伏电池成本和提升电池效率，使用铜电镀取代丝网印刷银浆制作光伏电池的栅线正在得到越来越多的关注和研究。而当采用铜电镀工艺取代银浆印刷工艺制备栅线时，铜电镀的掩膜开口通常是矩形或近似矩形，使得成形的栅线的纵截面为矩形或近似矩形，称为矩形栅线。然而矩形栅线无法增加栅线表面向各个方向的反射，因此在组件封装后会产生超过圆弧形栅线的封装损失，进而影响发电效率和生命周期内的发电量。圆弧形栅线的增反效果，用栅线的光学宽度来表征，通常为其物理最宽处的宽度的70％；矩形栅线的光学宽度通常为其物理最宽处的宽度的90％以上。
因此，本发明提出一种栅线的制备方法、电池片的制备方法及光伏电池，缩小栅线的光学宽度以提升光伏电池的光电转化效率。
另一方面，传统的丝网印刷工艺制备银栅线主要存在以下几个问题：第一， 印刷过程中需要对电池片施压，对厚度为100微米以下的电池片容易造成坏片率升高；第二，丝网印刷的分辨率低，所印银栅线的高宽比低。由于存在丝网的网络线使得目前的线宽降到50微米以下非常困难，为了使银浆能通过丝网，且不会断线，银浆必须有一定的流动性，这使得印好的银栅线会向外流淌，使线宽(栅线与电池片接触面的宽度)进一步增加，高宽比降低，增大了遮光面积，影响光电转化效率。因此，有必要提出一种栅线的制备方法、电池片的制备方法及光伏电池，能够制备低线宽的栅线，降低栅线的遮光面积，提升光伏电池的光电转化效率。
利用光伏电池测量量子效率的方式，通过测量层压后的电池片对不同波长的光产生载流子的量子效率，结合太阳光谱中的不同波长的光的能量进行积分，计算电池片被光斑覆盖的某个区域的短路电流。
当某个区域中包含一定面积的栅线时，栅线产生的遮光会减小短路电流，减小的比例与遮光面积成正比。
举例来说，当无遮光区域的短路电流为40mA/cm2时，如果在该区域引入2％的光学遮挡面积，那么短路电流将为39.2mA/cm2。而当一个具有宽度梯度的栅线的电池片最宽处在该区域产生的物理遮挡为3％的面积时，可以得出栅线的光学宽度为其物理最宽处的2％/3％＝66％。
再举例来说，如果一个栅线没有宽度梯度，当无遮光区域的短路电流为40mA/cm2时，栅线形成的物理遮挡为3％的面积时，即形成了3％的光学遮挡面积，短路电流为38.8mA/cm2。而如果一个栅线具有宽度梯度，当无遮光区域的短路电流为40mA/cm2时，物理遮挡为3％的面积时，实际只产生了2％的光学遮挡面积，因此获得的短路电流为39.2mA/cm2。相同条件下，设置有具有宽度梯度的栅线的电池片获得的短路电流大于未设置具有宽度梯度的栅线的电池片获得的短路电流，即具有宽度梯度的栅线的电池片光电转化效率更高。
下面结合附图和具体的实施例来对本发明的技术方案作进一步的阐述。
如图1或者图2所示，本发明的实施例提供一种栅线的制备方法，包括以下步骤：
S1、在电池片1的正面和/或反面涂布掩膜材料，使得掩膜材料固化形成掩膜2；
S2、根据掩膜2的性质，对掩膜2的局部区域进行曝光，以在掩膜2上形成具有宽度梯度的显影反应区；
S3、对位于显影反应区的掩膜2进行显影，以在显影反应区形成具有宽度梯度的掩膜开口3；
S4、在掩膜开口3中电镀金属，以形成具有宽度梯度的栅线4；
S5、去除掩膜2。
本发明实施例中的栅线的制备方法，可以在电池片1的表面上形成具有宽度梯度的栅线4，该电池片1在使用时，尤其是被封装到光伏组件中以后，具有宽度梯度的栅线4能够对入射光线产生多角度反射，使得入射光线能够在光伏组件内部的材料界面上再次反射回电池片1的表面，从而增加电池片的发电效率。
现有的网版印刷技术，无法直接印刷出具有宽度梯度的栅线4，即使偶然能够获得具有宽度梯度的栅线4，同一电池片1上的各栅线4的宽度梯度各不相同，或者说同一电池片1上的各栅线4的宽度梯度不一致，导致增反效果降低。而本发明实施例中的栅线的制备方法，通过光刻(显影和曝光)的方法，可以获 得宽度梯度一致的掩膜开口3，进而在宽度梯度一致的掩膜开口3中电镀金属，可以获得宽度梯度一致的栅线4，可以获得较好的增反效果。
现有的网版印刷技术，无法直接印刷出增反效果较好的或者复杂纵截面的具有宽度梯度的栅线4，例如图5中示出的各种具有宽度梯度的纵截面，而通过光刻(显影和曝光)的方法，可以获得需求的掩膜开口3，进而在需求的掩膜开口3中电镀金属，可以获得增反效果较好的或者复杂纵截面的具有宽度梯度的栅线4。
定义：与电池片1厚度方向垂直的两个面为正面和反面，或者电池片1上相背设置的两个较大的面为正面和反面；沿电池片1厚度方向延伸的面为侧面，或者除正面和反面之外的面均为侧面。电池片1的受光面，是指电池片1在使用时能够受光发电的一面或者两面，可以为正面和/或反面。
需要说明的是，曝光是指，掩膜2和光线发生光致交联或聚合或分解的光化学反应过程。显影是指，未经过光化学反应或者经过光化学反应的掩膜2与显影剂进一步发生反应生成掩膜缺口3的过程。
需要说明的是，宽度梯度是指沿着对象的上下方向，对象的宽度值从上向下有变化的现象，对象若被划分为由上至下依次分布的多层，则该顶层的下方存在至少一个宽度扩大层，该宽度扩大层的宽度大于其上方任一层的宽度。具体来说，对象从上到下依次被划分为第1层、第2层、……第N层，上述N为大于1的正整数，其中，第1层为顶层，第N层为底层，该底层临近电池片的表面。上述宽度扩大层是一个相对的概念，若第2层的宽度大于第1层的宽度，则第2层为宽度扩大层；第4层的宽度大于第1层至第3层中任一层的宽度，则第4层是宽度扩大层。
比较有代表性的宽度梯度为对象的宽度值从上向下递增的现象，尤其是纵截面为三角形、上窄下宽的梯形或上窄下宽的阶梯形状。例如，显影反应区的纵截面上窄下宽的梯形或上窄下宽的阶梯形状，可以视为显影反应区具有宽度梯度；掩膜开口3的纵截面上窄下宽的梯形或上窄下宽的阶梯形状，可以视为掩膜开口3具有宽度梯度；栅线4的纵截面为三角形、上窄下宽的梯形或上窄下宽的阶梯形状，可以视为栅线4具有宽度梯度。当然，对象的宽度梯度包括但不限于以上示例。
在一些实施例中，掩膜2的材料可以为耐酸性材料，可以采用碱性溶液浸泡去除掩膜2，例如氢氧化钠、氢氧化钾或氢氧化钙中的至少一种形成的碱性溶液。
在一些实施例中，制备方法还包括步骤S6，在栅线4的表面覆盖反射层或熔点低于300℃的合金焊层或者有机保护层，反射层、合金焊层和有机保护层统称为覆盖层5；其中，步骤S6设置在步骤S4之后且在步骤S5之前，或者步骤S6设置在步骤S5之后。合金焊层由锡与铅、铋、银、铜、铟、锌中的一种或几种形成。在栅线4的表面覆盖上述的反射层或合金焊层或有机保护层，能够使得该反射层或合金焊层或有机保护层在受热熔融回流后可以使得栅线4整体形成近似三角形或梯形。
步骤S6中在栅线4的表面上覆盖反射层或合金焊层或有机保护层，相应实现提升栅线4的表面的反射效果、提升栅线4的表面的焊接性能或保护栅线4的表面免受化学腐蚀的功能，同时使得栅线4的表面更加平整光滑，提升栅线4的增反效果。特别是，当步骤S5中获得的栅线4为阶梯状，反射层或合金焊层或有机保护层可以作为弥补材料，弥补栅线4上的阶梯空间，使得栅线4的纵截面形成近似三角形或梯形，提升栅线4的增反效果。在栅线4的表面覆盖反 射层或合金焊层或有机保护层，均可以采用电镀或者化学镀或者涂覆的方式制备而成。
具体地，如图1所示，可以在步骤S5结束后再执行步骤S6，即在去除掩膜2后再在栅线4的表面覆盖反射层或合金焊层或有机保护层，更方便形成反射层或合金焊层或有机保护层，避免了掩膜2的干扰，提升了栅线4的制备效率。如图2所示，还可以将步骤S6设置在步骤S4之后且在步骤S5之前，亦即先在栅线4的表面覆盖反射层或合金焊层或有机保护层再去除掩膜2。该方案中，栅线4和掩膜开口3之间可能没有足够的覆膜间隙用于容纳反射层或合金焊层或有机保护层，为了顺利在栅线4的表面上覆盖反射层或合金焊层或有机保护层，采用去膜液预先浸泡或者定点注入到栅线4和掩膜开口3的连接处，以获得覆膜间隙，然后再在栅线4的表面覆盖反射层或合金焊层或有机保护层，最后去除掩膜2；这样能够提前对栅线4进行覆膜保护，可以避免后道工序损伤栅线4。
在一些实施例中，对电池片1的双面(正面和反面)涂布掩膜材料，在电池片1的双面上均形成掩膜2，至少在电池片1的受光面形成具有宽度梯度的栅线4；当电池片1的结构为双面发电结构时，在电池片1的双面上均形成具有宽度梯度的栅线4。
具体地，对电池片1的双面(正面和反面)涂布掩膜材料，在电池片1的双面上均形成掩膜2；若电池片1为单面发电结构，即电池片仅有一面(正面或反面)为受光面，只对受光面上的部分掩膜2进行曝光和显影，形成具有宽度梯度的掩膜开口3，进而在具有宽度梯度的掩膜开口3中电镀金属形成具有宽度梯度的栅线4；若电池片1为双面发电结构，即电池片的双面(正面和反面)均为受光面，对电池片1的双面上的部分掩膜2分别进行曝光和显影，在电池片1的双面上分别形成具有宽度梯度的掩膜开口3，进而在具有宽度梯度的掩膜开口3中电镀金属，在电池片1的双面上分别形成具有宽度梯度的栅线4。电镀形成栅线4的过程中，电池片1的双面上的非开口区域若直接接触电镀液，也会被电镀，因此，无论电池片1是否为双面发电结构，电池片1的双面上均需要形成掩膜2，避免电池片1的双面上的非开口区域被电镀。
需要说明的是，本申请的实施例中提及的单面发电结构电池片1可以为BSF(Alμminiμm Back Surface Field，铝背场电池)、PERC(Passivated Emitter and Rear Cell，钝化发射极和背面电池)、HJT(Heterojunction with Intrinsic Thin Layer，晶体硅异质结太阳电池)、PSC(Perovskite Solar Cells，钙钛矿电池)或IBC(Interdigitated Back Contact，叉指式背接触电池)等结构电池。本申请的实施例中提及的双面发电结构电池片1可以为HJT、Topcon(Tunnel Oxide Passivating Contacts，隧穿氧化层钝化接触电池)或PSC等结构电池。
在一些实施例中，至少可以采用以下方法形成具有宽度梯度的显影反应区：曝光掩膜2上不需要开口的区域，使得掩膜2自电池片1的表面向远离电池片1的表面方向固化程度逐渐升高，以在掩膜2上形成具有宽度梯度的显影反应区；或者，曝光掩膜2上需要开口的区域，使得掩膜2自电池片1的表面向远离电池片1的表面方向固化程度逐渐降低，以在掩膜2上形成具有宽度梯度的显影反应区；
至少可以采用以下方法形成具有宽度梯度的掩膜开口3：根据掩膜2自电池片1的表面向远离电池片1的表面方向固化程度逐渐升高或者逐渐降低的情形，选择相应的显影剂与具有宽度梯度的显影反应区中的掩膜2发生显影反应，显影反应的反应速率自电池片1的表面向远离电池片1的表面方向逐渐减慢，以形成具有宽度梯度的掩膜开口3。
在一些实施例中，采用以下方法形成具有宽度梯度的显影反应区：在电池片1的表面上涂布形成多层掩膜2，每一层掩膜2具有不同的感光度；曝光多层掩膜2上不需要开口的区域，使得多层掩膜2自电池片1的表面向远离电池片1的表面方向固化程度逐层升高，以在掩膜2上形成具有宽度梯度的显影反应区；或者，曝光多层掩膜2上需要开口的区域，使得多层掩膜2自电池片1的表面向远离电池片1的表面方向固化程度逐层降低，以在掩膜2上形成具有宽度梯度的显影反应区；其中，调整光敏组分和/或光敏成分的浓度以形成不同感光度的多层掩膜2。在以上实施例中，可以采用均一光源进行一次性曝光，曝光过程简单，曝光效率更高。
示例地，如图1所示，在电池片1的表面上涂布形成三层掩膜2，每一层掩膜2具有不同的感光度，三层掩膜2自电池片1的表面向远离电池片1的表面方向感光度逐层降低，即靠近电池片1的表面的一层(最底层)掩膜2的感光度最高，远离电池片1的表面的一层(最上层)掩膜2的感光度最底，位于中间的一层掩膜2，其感光度小于相邻的下一层掩膜2的感光度但是大于相邻的上一层掩膜2的感光度。采用同一束光线对三层掩膜同时进行曝光，曝光三层掩膜2上需要开口的区域，曝光时间相同；在全部的多层掩膜2中，最底层的掩膜2的感光度最高，吸收光线的能量最多，使得最底层的掩膜2的固化程度最高，固化区域最大(也即发生固化的掩膜2的体积最多)；最上层的掩膜2的感光度最低，吸收光线的能量最少，使得最上层的掩膜2的固化程度最低，固化区域最小(也即发生固化的掩膜2的体积最少)；位于中间层的掩膜2，因其感光度小于相邻的下一层掩膜2的感光度但是大于相邻的上一层掩膜2的感光度，使得中间层的掩膜2的固化程度以及固化区域小于相邻的下一层掩膜2且大于相邻的上一层掩膜2；也就是说，自电池片1的表面向远离电池片1的表面方向，固化区域逐层减小，即形成了图1-2所示的阶梯形的显影反应区。
示例地，以电池片1的表面为原点建立坐标系，感光度为因变量y，多层掩膜2自电池片1的表面向上计算的层数为自变量x，当层数x为1时，假设其感光度为b，此时可以获得感光度y的计算公式y□□axn□b，a和n取决于掩膜2的自身性质，a为正数，主要由掩膜2中的光敏组分和/或光敏成分的浓度决定。理论上，当n为1时，多层掩膜2曝光后形成的显影反应区的截面大致为阶梯形，可以示例性地参考图5-1和图5-2中的图形。
示例地，以电池片1的表面为原点建立坐标系，感光度为因变量y，掩膜2与电池片1表面的距离为自变量x，即掩膜2在电池片1上的高度为x，当高度为0时，掩膜2与电池片1表面接触，假设其感光度为b，此时可以获得感光度y的计算公式y□□axn□b，a和n取决于掩膜2的自身性质，a为正数，主要由掩膜2中的光敏组分和/或光敏成分的浓度决定。理论上，当n为1时，掩膜2曝光后形成的显影反应区的截面大致为梯形或者三角形。
示例地，如图2所示，在电池片1的表面上涂布形成三层掩膜2，每一层掩膜2具有不同的感光度，三层掩膜2自电池片1的表面向远离电池片1的表面方向感光度逐层升高，即靠近电池片1的表面的一层(最底层)掩膜2的感光度最低，远离电池片1的表面的一层(最上层)掩膜2的感光度最高，位于中间的一层掩膜2，其感光度大于相邻的下一层掩膜2的感光度但是小于相邻的上一层掩膜2的感光度。采用同一束光线对三层掩膜同时进行曝光，曝光三层掩膜2上不需要开口的区域，曝光时间相同；在全部的多层掩膜2中，最底层的 掩膜2的感光度最低，吸收光线的能量最少，使得最底层的掩膜2的固化程度最低，固化区域最小(也即发生固化的掩膜2的体积最少)；最上层的掩膜2的感光度最高，吸收光线的能量最多，使得最上层的掩膜2的固化程度最高，固化区域最大(也即发生固化的掩膜2的体积最多)；位于中间层的掩膜2，因其感光度大于相邻的下一层掩膜2的感光度但是小于相邻的上一层掩膜2的感光度，使得中间层的掩膜2的固化程度以及固化区域大于相邻的下一层掩膜2且小于相邻的上一层掩膜2；也就是说，自电池片1的表面向远离电池片1的表面方向，多层掩膜2的固化区域逐层增大，同一层掩膜2上的曝光点为间隔设置，间隔设置的相邻的两个曝光点形成的固化区域不重叠，相邻的两个固化区域之间构成未固化区域，自电池片1的表面向远离电池片1的表面方向，未固化区域逐层减小，即形成了图2-2所示的阶梯形的显影反应区。
示例地，以电池片1的表面为原点建立坐标系，感光度为因变量y，多层掩膜2自电池片1的表面向上计算的层数为自变量x，当层数x为1时，假设其感光度为a+b，此时可以获得感光度y的计算公式y□axn□b，a和n取决于掩膜2的自身性质，a为正数，主要由掩膜2中的光敏组分和/或光敏成分的浓度决定。理论上，当n为1时，多层掩膜2曝光后形成的显影反应区的截面大致为阶梯形，可以示例性地参考图5-1和图5-2中的图形。
示例地，以电池片1的表面为原点建立坐标系，感光度为因变量y，掩膜2与电池片1表面的距离为自变量x，即掩膜2在电池片1上的高度为x，当高度为0时，掩膜2与电池片1表面接触，假设其感光度为a+b，此时可以获得感光度y的计算公式y□axn□b，a和n取决于掩膜2的自身性质，a为正数，主要由掩膜2中的光敏组分和/或光敏成分的浓度决定。理论上，当n为1时，掩膜2曝光后形成的显影反应区的截面大致为梯形或者三角形。
在一些实施例中，采用以下方法形成具有宽度梯度的显影反应区：在电池片1的表面上涂布形成多层掩膜2，每一层掩膜2具有不同的吸收峰值；曝光多层掩膜2上不需要开口的区域，使得多层掩膜2自电池片的表面向远离电池片1的表面方向固化程度逐层升高，以在掩膜2上形成具有宽度梯度的显影反应区；或者，曝光多层掩膜2上需要开口的区域，使得多层掩膜2自电池片1的表面向远离电池片1的表面方向固化程度逐层降低，以在掩膜2上形成具有宽度梯度的显影反应区。
示例地，如图1所示，在电池片1的表面上涂布形成三层掩膜2，每一层掩膜2具有不同的吸收峰值，选定一个波段范围的光线，例如波段为380nm-410nm，三层掩膜2自电池片1的表面向远离电池片1的表面方向对选定波段范围的光线的敏感度逐层降低，即靠近电池片1的表面的一层(最底层)掩膜2对选定波段范围的光线的敏感度最高，远离电池片1的表面的一层(最上层)掩膜2对选定波段范围的光线的敏感度最底，位于中间的一层掩膜2，其对选定波段范围的光线的敏感度小于相邻的下一层掩膜2对选定波段范围的光线的敏感度但是大于相邻的上一层掩膜2对选定波段范围的光线的敏感度。采用同一束光线对三层掩膜同时进行曝光，曝光三层掩膜2上需要开口的区域，曝光时间相同；在全部的多层掩膜2中，最底层的掩膜2对选定波段范围的光线的敏感度最高，吸收光线的能量最多，使得最底层的掩膜2的固化程度最高，固化区域最大(也即发生固化的掩膜2的体积最多)；最上层的掩膜2对选定波段范围的光线的敏感度最低，吸收光线的能量最少，使得最上层的掩膜2的固化程度最低，固 化区域最小(也即发生固化的掩膜2的体积最少)；位于中间层的掩膜2，因其对选定波段范围的光线的敏感度小于相邻的下一层掩膜2对选定波段范围的光线的敏感度但是大于相邻的上一层掩膜2对选定波段范围的光线的敏感度，使得中间层的掩膜2的固化程度以及固化区域小于相邻的下一层掩膜2且大于相邻的上一层掩膜2；也就是说，自电池片1的表面向远离电池片1的表面方向，固化区域逐层减小，即形成了图1-2所示的阶梯形的显影反应区。
示例地，如图2所示，在电池片1的表面上涂布形成三层掩膜2，每一层掩膜2具有不同的吸收峰值，选定一个波段范围的光线，例如波段为380nm-410nm，三层掩膜2自电池片1的表面向远离电池片1的表面方向选定波段范围的光线的敏感度逐层升高，即靠近电池片1的表面的一层(最底层)掩膜2对选定波段范围的光线的敏感度最低，远离电池片1的表面的一层(最上层)掩膜2对选定波段范围的光线的敏感度最高，位于中间的一层掩膜2，其选定波段范围的光线的敏感度大于相邻的下一层掩膜2对选定波段范围的光线的敏感度但是小于相邻的上一层掩膜2对选定波段范围的光线的敏感度。采用同一束光线对三层掩膜同时进行曝光，曝光三层掩膜2上不需要开口的区域，曝光时间相同；在全部的多层掩膜2中，最底层的掩膜2对选定波段范围的光线的敏感度最低，吸收光线的能量最少，使得最底层的掩膜2的固化程度最低，固化区域最小(也即发生固化的掩膜2的体积最少)；最上层的掩膜2对选定波段范围的光线的敏感度最高，吸收光线的能量最多，使得最上层的掩膜2的固化程度最高，固化区域最大(也即发生固化的掩膜2的体积最多)；位于中间层的掩膜2，因其对选定波段范围的光线的敏感度大于相邻的下一层掩膜2对选定波段范围的光线的敏感度但是小于相邻的上一层掩膜2对选定波段范围的光线的敏感度，使得中间层的掩膜2的固化程度以及固化区域大于相邻的下一层掩膜2且小于相邻的上一层掩膜2；也就是说，自电池片1的表面向远离电池片1的表面方向，多层掩膜2的固化区域逐层增大，同一层掩膜2上的曝光点为间隔设置，间隔设置的相邻的两个曝光点形成的固化区域不重叠，相邻的两个固化区域之间构成未固化区域，自电池片1的表面向远离电池片1的表面方向，未固化区域逐层减小，即形成了图2-2所示的阶梯形的显影反应区。
在一些实施例中，采用以下方法形成具有宽度梯度的显影反应区：在电池片1的表面上涂布形成一层掩膜2；曝光掩膜2上不需要开口的区域，调整曝光的焦点位置和/或光强和/或波长，使得掩膜2自电池片1的表面向远离电池片1的表面方向对曝光能量的吸收逐渐增多，进而使得掩膜2自电池片1的表面向远离电池片1的表面方向固化程度逐渐升高，以在掩膜2上形成具有宽度梯度的显影反应区；或者，曝光掩膜2上需要开口的区域，调整曝光的焦点位置和/或光强和/或波长，使得掩膜2自电池片1的表面向远离电池片1的表面方向对曝光能量的吸收逐渐减少，进而使得使得掩膜2自电池片1的表面向远离电池片1的表面方向固化程度逐层降低，以在掩膜2上形成具有宽度梯度的显影反应区。以上实施例中，采用单层掩膜2，单层掩膜2容易被制备，可以降低掩膜2的生产成本。
示例地，如图3所示，在电池片1的表面上涂布形成一层掩膜2，为了方便描述，将掩膜2划分为虚拟的三层，自电池片1的表面向远离电池片1的表面方向依次为第一层21、第二层22和第三层23，自电池片1的表面向远离电池片1的表面方向对三层掩膜2逐层曝光，曝光掩膜2上需要开口的区域，曝光的光强自电池片1的表面向远离电池片1的表面方向逐层减少，同一曝光点的曝光次数自电池片1的表面向远离电池片1的表面方向逐层减少，曝光的波长自电池片1的表面向远离电池片1的表面方向逐层加长；其目的是使得靠近电 池片1的表面的一层(最底层)掩膜2吸收光线的能量最多，远离电池片1的表面的一层(最上层)掩膜2吸收光线的能量最少，位于中间的一层掩膜2吸收光线的能量小于相邻的下一层掩膜2吸收光线的能量但是大于相邻的上一层掩膜2吸收光线的能量；进而使得最底层的掩膜2的固化程度最高，固化区域最大(也即发生固化的掩膜2的体积最多)，最上层的掩膜2的固化程度最低，固化区域最小(也即发生固化的掩膜2的体积最少)，中间层的掩膜2的固化程度以及固化区域小于相邻的下一层掩膜2且大于相邻的上一层掩膜2；也就是说，自电池片1的表面向远离电池片1的表面方向，固化区域逐层减小，最终形成图3-4所示的阶梯形的显影反应区。
示例地，如图4所示，在电池片1的表面上涂布形成一层掩膜2，为了方便描述，将掩膜2划分为虚拟的三层，自电池片1的表面向远离电池片1的表面方向依次为第一层21、第二层22和第三层23，自电池片1的表面向远离电池片1的表面方向对三层掩膜2逐层曝光，曝光掩膜2上不需要开口的区域，曝光的光强自电池片1的表面向远离电池片1的表面方向逐层增加，同一曝光点的曝光次数自电池片1的表面向远离电池片1的表面方向逐层增加，曝光的波长自电池片1的表面向远离电池片1的表面方向逐层缩短；其目的是使得靠近电池片1的表面的一层(最底层)掩膜2吸收光线的能量最少，远离电池片1的表面的一层(最上层)掩膜2吸收光线的能量最多，位于中间的一层掩膜2吸收光线的能量大于相邻的下一层掩膜2吸收光线的能量但是小于相邻的上一层掩膜2吸收光线的能量；进而使得最底层的掩膜2的固化程度最低，固化区域最小(也即发生固化的掩膜2的体积最少)，最上层的掩膜2的固化程度最高，固化区域最大(也即发生固化的掩膜2的体积最多)，中间层的掩膜2的固化程度以及固化区域大于相邻的下一层掩膜2且小于相邻的上一层掩膜2；也就是说，自电池片1的表面向远离电池片1的表面方向，多层掩膜2的固化区域逐层增大，同一层掩膜2上的曝光点为间隔设置，间隔设置的相邻的两个曝光点形成的固化区域不重叠，相邻的两个固化区域之间构成未固化区域，自电池片1的表面向远离电池片1的表面方向，未固化区域逐层减小，最终形成图4-4所示的阶梯形的显影反应区。
在一些实施例中，在电池片1的表面上涂布形成一层掩膜2，掩膜2的透光量(或者透光能力)随光线穿透掩膜2的厚度值递减；曝光掩膜2上不需要开口的区域，以在掩膜上形成具有宽度梯度的显影反应区。具体地，曝光光线进入掩膜2后，掩膜2会不断吸收和反射光线，使得掩膜2的透光量随光线穿透掩膜2的厚度值递减，进而曝光量自电池片1的表面向远离电池片1的表面方向逐层增加，即曝光区域(固化区域)自电池片1的表面向远离电池片1的表面方向逐层增加，掩膜2上两个曝光区域之间的未曝光区域(未固化区域)则构成具有宽度梯度的显影反应区。
在一些实施例中，如图6或者图7所示，栅线的制备方法包括以下步骤：将电池片1的表面被划分为第一区域和第二区域；在第一区域上形成第一掩膜2a，第一掩膜2a可以是单层或者多层，在第二区域上形成第二掩膜2b，第二掩膜2b可以是单层或者多层；根据第一掩膜2a的性质(正抗蚀剂或负抗蚀剂)，对第一掩膜2a的局部区域进行曝光，以在第一掩膜2a上形成具有宽度梯度的第一显影反应区；对位于第一显影反应区的第一掩膜2a进行显影，以在第一显影反应区形成具有宽度梯度的第一掩膜开口31；在第一掩膜开口31中电镀第一金属，以形成具有宽度梯度的第一栅线41。根据第二掩膜2b的性质，对第二掩膜2b的局部区域进行曝光，以在第二掩膜2b上形成具有宽度梯度的第二显影反应区；对位于第二显影反应区的第二掩膜2b进行显影，以在第二显影反应区形成 具有宽度梯度的第二掩膜开口32；在第二掩膜开口32中电镀第二金属，以形成具有宽度梯度的第二栅线42。其中，第一金属和第二金属可以为相同的金属或者不同的金属。第一区域和第二区域均位于电池片1的同一面上，或者第一区域和第二区域分别位于电池片1的两个面上，或者电池片1的两个面上均设置有第一区域和第二区域。
若第一掩膜2a为单层，为了方便描述，将第一掩膜2a划分为虚拟的三层，自电池片1的表面向远离电池片1的表面方向依次为第一掩膜第一层2a1、第一掩膜第二层2a2和第一掩膜第三层2a3，参考前述的实施例，可以通过控制第一掩膜2a每一层的感光度和/或吸收峰值，或者控制在第一掩膜2a每一层上的曝光参数，例如曝光的焦点位置，同一曝光点的曝光次数，曝光光强或者波长，以获得具有宽度梯度的第一显影反应区。同理，将第二掩膜2b划分为虚拟的三层，自电池片1的表面向远离电池片1的表面方向依次为第二掩膜第一层2b1、第二掩膜第二层2b2和第二掩膜第三层2b3，参考前述的实施例，可以通过控制第二掩膜2b每一层的感光度和/或吸收峰值，或者控制在第二掩膜2b每一层上的曝光参数，例如曝光的焦点位置，同一曝光点的曝光次数，曝光光强或者波长，以获得具有宽度梯度的第二显影反应区。
当然，若第一掩膜2a和第二掩膜2b均为多层，也可以采用应用于单层掩膜2上的技术手段形成具有宽度梯度的显影反应区。
示例地，如图6所示，电池片1可以为IBC结构，第一区域和第二区域均位于电池片1的同一面上(例如正面上)，在第一区域上形成第一掩膜2a，在第二区域上形成第二掩膜2b；对第一掩膜2a的开口区域进行曝光，以在第一掩膜2a上形成具有宽度梯度的第一显影反应区；对位于第一显影反应区的第一掩膜2a进行显影，以在第一显影反应区形成具有宽度梯度的第一掩膜开口31；在第一掩膜开口31中电镀第一金属，以形成具有宽度梯度的第一栅线41。对第二掩膜2b的开口区域进行曝光，以在第二掩膜2b上形成具有宽度梯度的第二显影反应区；对位于第二显影反应区的第二掩膜2b进行显影，以在第二显影反应区形成具有宽度梯度的第二掩膜开口32；在第二掩膜开口32中电镀第二金属，以形成具有宽度梯度的第二栅线42。其中，第一金属和第二金属可以为相同的金属或者不同的金属。优选地，第一金属和第二金属分别选自银、铜、铝、镁、铬、镍、钼、锡、钛、钨或者以上任意两者以上组成的合金或者叠层。
在优选的实施例中，为提升涂布效率，在第一区域上形成第一掩膜2a和在第二区域上形成第二掩膜2b可以同步进行，接着完成第一掩膜开口31以及在第一掩膜开口31中电镀第一金属，最后完成第二掩膜开口32以及在第二掩膜开口32中电镀第二金属。如果同时完成第一掩膜开口31和第二掩膜开口32，在第一掩膜开口31中电镀第一金属时，若不对第二掩膜开口32进行保护，在第二掩膜开口32中也会电镀第一金属，而先完成第一掩膜开口31以及在第一掩膜开口31中电镀第一金属，再完成第二掩膜开口32以及在第二掩膜开口32中电镀第二金属，在电镀第一金属时，第二掩膜开口32还不存在，也就不会在第二掩膜开口32中电镀第一金属。进一步地，在第二掩膜开口32中电镀第二金属时，位于第一掩膜开口31中的第一金属(第一栅线41)的表面可能也会被电镀上第二金属；如果工艺需要，可以在第一栅线41的表面电镀上第二金属，即第一栅线41为金属叠层结构，第二栅线42单一金属，例如第一金属为铜，第二金属为锡，而铜容易氧化，因此可以继续在铜的表面电镀锡；如果需要避免在第一栅线41的表面电镀上第二金属，可以在电镀第二金属之前，预先在第一栅线41的表面涂布保护层，例如涂布掩膜2。
在一些实施例中，在电池片1的侧面涂布掩膜材料，使得掩膜材料固化形成掩膜2，在掩膜开口3中电镀金属时，可以避免：在电池片1的侧面电镀金属，导致电池片1的正面和背面导通，影响电池片1的效率。
在一些实施例中，根据掩膜2的性质(正抗蚀剂或负抗蚀剂)，对掩膜2的局部区域进行曝光，以在掩膜2上形成纵截面为梯形或阶梯形的显影反应区；对位于显影反应区的掩膜2进行显影，以在显影反应区形成纵截面为梯形或阶梯形的掩膜开口3；在掩膜开口3中电镀金属，以形成纵截面为梯形或阶梯形的栅线4。具有宽度梯度的栅线4包括纵截面为三角形或梯形或阶梯形的栅线4，纵截面为梯形或阶梯形的栅线4容易通过电镀直接形成，或者可以通过在栅线4的表面覆盖反射层或熔点低于300℃的合金焊层或者有机保护层，使得栅线4的纵截面形成为三角形或梯形，即纵截面为三角形或梯形或阶梯形的栅线4制备过程简单。
优选地，掩膜开口3的纵截面为梯形，梯形的底角为45-89度，使得在掩膜开口3中可以电镀获得纵截面为梯形的栅线4，梯形栅线4的纵截面的底角为45-89度，能够平衡栅线4的导电性能的同时，使得栅线4的增反效果最好。对于纵截面为梯形的栅线4，当梯形的底边和高度值固定不变，梯形的底角越大，梯形的面积(栅线4纵截面的面积)越大，栅线4的体积越大，栅线4的导电性能越好，但是栅线4的增反效果越差。因此，为了平衡栅线4的增反效果和导电性能，需要控制梯形栅线4的纵截面的底角大小，优选的范围为45-89度。
需要说明的是，本申请所提及的三角形或梯形或阶梯形等形状，是指在整体观察的情况下，对象构成近似的三角形或梯形或阶梯形等形状，在微小尺度下观察，这些形状的边线可能不是直线，这些形状的角可能不是两条直线的交点。可以理解的是，工业上无法生产出几何形状的产品，对任何工业产品的几何形状的描述，都是近似描述。
在一些实施例中，电池片1上设置有介质层，在显影反应区形成具有宽度梯度的掩膜开口3之后，去除掩膜开口3正下方的介质层，可以采用激光去除或者化学刻蚀去除，使得掩膜开口3连通到电池片1的导电结构层，例如种子层、TCO层或者半导体掺杂层，进而使得金属能够被顺利电镀到导电结构层形成栅线4。
在一些实施例中，具有宽度梯度的栅线4，除了纵截面为三角形或梯形的栅线4外，还可以为满足宽度梯度定义的其他形状，图5示例性地给出了一些具有宽度梯度的栅线4的纵截面的示意图。
图5-1至图5-5示出的5个子实施例中，栅线4被划分为由上至下依次分布的4层，分别为第1层4a、第2层4b、第3层4c、第4层4d，其中，第1层4a为顶层，第4层4d为底层，第2层4b的宽度大于第1层4a的宽度，第3层4c的宽度大于第2层4b及第1层4a的宽度，第4层4d的宽度大于第3层4c、第2层4b及第1层4a的宽度，如此，这5个子实施例中，此处的第2层4b、第3层4c、第4层4d均为宽度扩大层。这5个子实施例的区别主要在于每一层的形状不同，具体如下：
图5-1示出的第一子实施例中，栅线4每一层的纵截面的两个侧边均为沿竖直方向延伸的直线，也就是说，栅线4上下方向上每一层的纵截面呈矩形或方形，该栅线4的纵截面整体呈阶梯状。
图5-2示出的第二子实施例中，栅线4每一层的纵截面的两个侧边均为沿上下方向倾斜延伸的斜线，此处，该斜线由上至下向外逐渐倾斜延伸，使得每一层的纵截面均呈上窄下宽的梯形。且在实施例中，栅线4所有层中沿上下方 向任意相邻的两层中，上层的最大宽度小于下层的最小宽度，如第1层4a的最下部的宽度值小于第2层4b最上部的宽度值，第2层4b最下部的宽度值小于第3层4c最上部的宽度值，第3层4c最下部的宽度值亦小于第4层4d最上部的宽度值。
图5-3示出的第三子实施例中，栅线4所有层中，一些层纵截面的两个侧边为沿竖直方向延伸的直线，这些层的纵截面呈矩形或方形，此处具体为第1层4a与第3层4c；另一些层的纵截面的两个侧边均为自上而下逐渐向外倾斜延伸的斜线，这些层的纵截面呈梯形，此处具体为第2层4b与第4层4d。其中，第1层4a的宽度值小于第2层4b的最小宽度值，第2层4b的最大宽度值小于第3层4c的宽度值，第3层4c的宽度值小于第4层4d的最小宽度值。
图5-4示出的第四子实施例中，栅线4所有层中，每一层纵截面的两个侧边均为沿上下方向延伸的弧线，此处，该弧线为由上至下向内拱起的弧线，使得每一层的纵截面均呈弧边梯形。需要说明的是，弧边梯形是指梯形的两个腰边至少一个被替换为弧线后形成的图形。
图5-5示出的第五子实施例中，栅线4第1层4a的纵截面的两个侧边为沿上下方向逐渐向外倾斜延伸的斜线，该第1层4a的纵截面为梯形；第2层4b的纵截面的两个侧边为沿竖直方向延伸的直线，该第2层4b的纵截面为矩形或方形；第3层4c的纵截面的两个侧边为沿上下方向延伸的弧线，此处弧形具体为由上至下向外拱起的弧形，该第3层4c的纵截面呈弧边梯形；第4层4d的纵截面的两个侧边为沿上下方向逐渐向外倾斜延伸的斜线，该第4层4d的纵截面为梯形。其中，第1层4a最下部的宽度值小于第2层4b的宽度值，第2层4b的宽度值小于第3层4c最上部的宽度值，第3层4c最下部的宽度值小于第4层4d最上部的宽度值。
图5-6示出的第六子实施例与前述图5-1至图5-5示出的5个子实施例的主要区别在于本子实施例中第2层4b、第4层4d为宽度扩大层。具体地：第1层4a、第2层4b、第3层4c、第4层4d的纵截面均为梯形，每一层的纵截面的两个侧边为沿上下方向逐渐向外倾斜延伸的斜线。第2层4b的宽度大于第1层4a的宽度；第3层4c的宽度小于第2层4b的宽度；第4层4d的宽度大于第3层4c的宽度且大于第2层4b、第1层4a的宽度，上述第2层4b相对于第1层4a为一个宽度扩大层，第4层4d相对于第1层4a、第2层4b及第3层4c为另一个宽度扩大层。
图5-7至图5-9示出的3个子实施例中，栅线4的纵截面为弧边三角形，该栅线4的宽度由上至下依次递增，具体地，该纵截面包括底边L0以及侧边L1、侧边L2，其中，侧边L1与侧边L2均为弧线。其中，图5-7示出的第七子实施例中，侧边L1与侧边L2均为自上而下向内拱起的弧线；图5-8示出的第八子实施例中，侧边L1与侧边L2均为自上而下向外拱起的弧线；图5-9示出的第九子实施例中，一条侧边L1为自上而下向外拱起的弧线，另一条侧边L2为自上而下向内拱起的弧线。
图5-10至图5-12示出的3个子实施例中，栅线4的纵截面为弧边梯形，该栅线4的宽度由上至下依次递增，具体地，该纵截面包括底边L0、顶边L3以及侧边L1、侧边L2，其中，侧边L1与侧边L2均为弧线。其中，图5-10示出的第十子实施例中，侧边L1与侧边L2均为自上而下向内拱起的弧线；图5-11示出的第十一子实施例中，侧边L1与侧边L2均为自上而下向外拱起的弧线；图5-12示出的第十二子实施例中，一条侧边L1为自上而下向外拱起的弧线，另一条侧边L2为自上而下向内拱起的弧线。
当然，具有宽度梯度的栅线4的纵截面的形状不限于以上示例。电镀制备 的栅线4，掩膜开口3类似于栅线4的模子，栅线4的形状由掩膜开口3的形状决定，因此，显影反应区的纵截面的形状和栅线4的纵截面的形状相同，掩膜开口3的纵截面的形状和栅线4的纵截面的形状相同，即显影反应区的纵截面和掩膜开口3的纵截面的形状可以参考图5中的示例。
需要说明的是，栅线的纵截面是指与栅线长度延伸方向相垂直的平面与栅线所相交的截面。
需要说明的是，光伏组件包括光伏电池和封装层，光伏电池包括至少一个电池片1及其上的栅线4。
在一些实施例中，掩膜2为多层，优选为2～10层，进一步优选为3～5层。掩膜的层数太少，无法较好地制备具有宽度梯度的掩膜开口3；掩膜的层数太多，则使得制备工艺以及实现该工艺的设备较为复杂，使得制备成本升高，制备效率降低。当相邻两层的掩膜开口3之间具有较小的宽度差，所有的掩膜开口3沿上下方向相互拼合使得其纵截面形成梯形或阶梯形状，优选形成等腰梯形，电镀后可以形成相应形状的具有宽度梯度的栅线4。
在前述的实施例中，利用光致交联或聚合或分解产生具有宽度梯度的显影反应区，能够获得较小宽度的显影反应区；通过显影可以获得较小宽度的掩膜开口3，在掩膜开口3中电镀金属可以获得较小线宽的栅线4，栅线4的线宽w可以达到5微米≤w＜50微米，优选为5微米≤w≤20微米或者20微米≤w≤40微米，更优选为5微米≤w＜10微米。而网版印刷受限于网版开口尺寸，以及印刷的材料本身的性能，无法获得较小线宽的栅线4，其栅线4的线宽w一般为50微米≤w≤200微米。前述实施例形成的栅线4的线宽相比现有技术中栅线4的线宽更低，降低了栅线4的遮光面积，有利于提升电池片1的光电转化效率。
本发明的实施例还提供了一种电池片的制备方法，电池片1上的栅线4采用以下步骤制备：
S1、在电池片1的正面和/或反面涂布掩膜材料，使得掩膜材料固化形成掩膜2；
S2、根据掩膜2的性质，对掩膜2的局部区域进行曝光，以在掩膜2上形成具有宽度梯度的显影反应区；
S3、对位于显影反应区的掩膜2进行显影，以在显影反应区形成具有宽度梯度的掩膜开口3；
S4、在掩膜开口3中电镀金属，以形成具有宽度梯度的栅线4；
S5、去除掩膜2。
该电池片的制备方法的主要改进点在于栅线的制备方法，因此该电池片的制备方法具备前述实施例中栅线的制备方法的技术效果。另外，前述实施例中针对栅线的制备方法的全部改进和技术方案也可以直接引用或者间接应用到电池片的制备方法中。本发明的实施例还提供了一种光伏电池，该光伏电池包括电池片1和设置在电池片1上具有宽度梯度的栅线4，该宽度梯度的栅线4具有增反效果，能够增加光伏电池的发电效率。
在一些实施例中，宽度梯度的栅线4可以根据前述的栅线的制备方法制备获得。
在一些实施例中，栅线4的纵截面呈三角形或梯形或阶梯形。
在一些实施例中，栅线4的表面还覆盖有亮锡或者亮银的反射层；或者栅线4的表面覆盖有熔点低于300℃的合金焊层，合金焊层为锡与铅、铋、银、铜、 铟和锌中的一种或几种形成；或者栅线4的表面覆盖有有机保护层。
在一些实施例中，电池片的至少受光面设置有的栅线4，或者电池片的两面均设置有的栅线4。
在一些实施例中，栅线4为多根，位于电池片同一面上的多根栅线4的材料为不同金属和/或位于电池片不同面上的多根栅线4的材料为不同金属。栅线4的材料可以选自银、铜、铝、镁、铬、镍、钼、锡、钛、钨或者以上任意两者以上组成的合金或者叠层。
例如，电池片的正面或者反面上设置有多根栅线4，电池片的正面或者反面被划分为A区域和B区域，其中位于A区域的栅线4为第一种金属，位于B区域的栅线4为第二种金属；优选地，第一种金属为银或铜，第二种金属为铝。
例如，电池片的正面和反面上均设置有多根栅线4，电池片正面上的栅线4均为第一种金属，电池片反面上的栅线4均为第二种金属；第一种金属为银或铜，第二种金属为铝。
例如，电池片的正面和反面上均设置有多根栅线4，电池片的正面被划分为A区域和B区域，其中位于A区域的栅线4为第一种金属，位于B区域的栅线4为第二种金属；电池片反面上的栅线4均为第一种金属或第二种金属或第三种金属；优选地，第一种金属为银或铜，第二种金属为铝，第三种金属为镍。
例如，电池片的正面和反面上均设置有多根栅线4，电池片的正面被划分为A区域和B区域，其中位于A区域的栅线4为第一种金属，位于B区域的栅线4为第二种金属；电池片的反面被划分为C区域和D区域，其中位于C区域的栅线4为第一种金属或第二金属，位于D区域的栅线4为第三种金属；优选地，第一种金属为银或铜，第二种金属为铝，第三种金属为镍。
例如，电池片的正面和反面上均设置有多根栅线4，电池片的正面被划分为A区域和B区域，其中位于A区域的栅线4为第一种金属，位于B区域的栅线4为第二种金属；电池片的反面被划分为C区域和D区域，其中位于C区域的栅线4为第三种金属，位于D区域的栅线4为第四种金属；优选地，第一种金属为铜外镀锡的叠层，第二种金属为铝，第三种金属为镍，第四种金属为锡。
在一些实施例中，栅线的最小线宽小于50微米且大于或等于10微米，比现有技术中栅线4的线宽更低，降低了栅线4的遮光面积，可以提升电池片1的光电转化效率。
在一些具体的实施例中，选择T1，T2和T3三组210mm×105mm异质结双面电池进行试验，每组包括20片电池片，均采用单面光照，栅线材料为铜，除表中列出的因素外，电池片的其他参数保持相同，试验结果如表1所示。
表1栅线的线宽对电池片性能的影响试验结果
其中，短路电流和效率是20片电池片的平均值，细栅线宽和细栅数量的乘积称为总线宽，短路电流和总线宽的比值称为线宽电流，效率和总线宽的比值 称为线宽效率。
从表1中T1和T2组数据可以看出，在其他因素相同的情况下，栅线越细，短路电流越大，效率越高，线宽电流越大，线宽效率越高，即细栅线可以提升电池片的效率。T3组中的细栅线宽和细栅数量，与T1和T2组均不相同，为了在单一变量的前提下进行比较，引入了总线宽的概念，总线宽能够体现全部栅线对电池的遮挡面积；在T1至T3组试验中，随着总线宽值逐渐减小，短路电流逐渐曾大，效率逐渐增大，线宽电流逐渐增大，线宽效率逐渐增大，同样可以得出细栅线可以提升电池片的效率。因此，有必要采取电镀的方法制备更细的栅线以及具有更细的栅线的电池片。
在一些具体的实施例中，选择T4和T5两组210mm×105mm异质结双面电池进行试验，每组包括20片电池片，均采用单面光照，栅线材料为铜，全部的电池片通过本申请实施例中的电镀方法电镀形成栅线，除表中列出的因素外，电池片的其他参数保持相同，试验结果如表2所示。
表2宽度梯度的栅线对电池片性能的影响试验结果
从T4和T5组试验可以得出，梯形栅线(具有宽度梯度的栅线)比矩形栅线(不具有宽度梯度的栅线)的功率封装效率以及电流封装效率都要高，即具有宽度梯度的栅线的电池片，经过封装获得的光伏组件效率更高。
上述实施例只为说明本发明的技术构思及特点，其目的在于让熟悉此项技术的人士能够了解本发明的内容并加以实施，并不能以此限制本发明的保护范围，凡根据本发明精神实质所作的等效变化或修饰，都应涵盖在本发明的保护范围内。

Claims (18)

  1. 一种栅线的制备方法，其特征在于，包括如下步骤：
    S1、在电池片的正面和/或反面涂布掩膜材料，使得所述掩膜材料固化形成掩膜；
    S2、根据所述掩膜的性质，对所述掩膜的局部区域进行曝光，以在所述掩膜上形成具有宽度梯度的显影反应区；
    S3、对位于所述显影反应区的所述掩膜进行显影，以在所述显影反应区形成具有宽度梯度的掩膜开口；
    S4、在所述掩膜开口中电镀金属，以形成具有宽度梯度的栅线；
    S5、去除所述掩膜。
  2. 根据权利要求1所述的栅线的制备方法，其特征在于，所述制备方法还包括：
    步骤S6、在所述栅线表面覆盖反射层或熔点低于300℃的合金焊层或者有机保护层；
    其中，所述步骤S6设置在所述步骤S4之后且在所述步骤S5之前，或者所述步骤S6设置在所述步骤S5之后。
  3. 根据权利要求1所述的栅线的制备方法，其特征在于：对所述电池片的双面涂布所述掩膜材料，至少在所述电池片的受光面形成所述具有宽度梯度的栅线；当所述电池片的结构为双面发电结构时，在所述电池片的双面上均形成所述具有宽度梯度的栅线。
  4. 根据权利要求1所述的栅线的制备方法，其特征在于：
    所述步骤S2包括：曝光所述掩膜上不需要开口的区域，使得所述掩膜自所述电池片的表面向远离电池片的表面方向固化程度逐渐升高，以在所述掩膜上形成具有宽度梯度的显影反应区；或者，曝光所述掩膜上需要开口的区域，使得所述掩膜自所述电池片的表面向远离电池片的表面方向固化程度逐渐降低，以在所述掩膜上形成所述具有宽度梯度的显影反应区；
    所述步骤S3包括：根据所述掩膜自所述电池片的表面向远离电池片的表面方向固化程度逐渐升高或者逐渐降低的情形，选择相应的显影剂与所述具有宽度梯度的显影反应区中的掩膜发生显影反应，以形成所述具有宽度梯度的掩膜开口。
  5. 根据权利要求1所述的栅线的制备方法，其特征在于，包括如下步骤：
    S11、在所述电池片的表面上涂布形成多层所述掩膜，每一层所述掩膜具有不同的感光度；
    S21、曝光多层所述掩膜上不需要开口的区域，使得多层所述掩膜自所述电池片的表面向远离电池片的表面方向固化程度逐层升高，以在所述掩膜上形成具有宽度梯度的显影反应区；或者，曝光多层所述掩膜上需要开口的区域，使得多层所述掩膜自所述电池片的表面向远离电池片的表面方向固化程度逐层降低，以在所述掩膜上形成所述具有宽度梯度的显影反应区；
    其中，调整光敏组分和/或光敏成分的浓度以形成不同感光度的多层所述掩膜；
    或者，
    S12、在所述电池片的表面上涂布形成多层所述掩膜，每一层所述掩膜具有不同的吸收峰值；
    S22、曝光多层所述掩膜上不需要开口的区域，使得多层所述掩膜自所述电池片的表面向远离电池片的表面方向固化程度逐层升高，以在所述掩膜上形成具有宽度梯度的显影反应区；或者，曝光多层所述掩膜上需要开口的区域，使得多层所述掩膜自所述电池片的表面向远离电池片的表面方向固化程度逐层降低，以在所述掩膜上形成所述具有宽度梯度的显影反应区；
    或者，
    S13、在所述电池片的表面上涂布形成一层所述掩膜；
    S23、曝光所述掩膜上不需要开口的区域，调整曝光的焦点位置和/或光强和/或波长，使得所述掩膜自所述电池片的表面向远离电池片的表面方向对曝光能量的吸收逐渐增多，以在所述掩膜上形成具有宽度梯度的显影反应区；或者，曝光所述掩膜上需要开口的区域，调整曝光的焦点位置和/或光强和/或波长，使得所述掩膜自所述电池片的表面向远离电池片的表面方向对曝光能量的吸收逐渐减少，以在所述掩膜上形成所述具有宽度梯度的显影反应区。
    或者，
    S14、在所述电池片的表面上涂布形成一层所述掩膜，所述掩膜的透光量随光线穿透所述掩膜的厚度值递减；
    S24、曝光所述掩膜上不需要开口的区域，以在所述掩膜上形成具有宽度梯度的显影反应区。
  6. 根据权利要求1所述的栅线的制备方法，其特征在于：
    将所述电池片的表面被划分为第一区域和第二区域；
    在第一区域上形成第一掩膜，在第二区域上形成第二掩膜；
    根据所述第一掩膜的性质，对所述第一掩膜的局部区域进行曝光，以在所述第一掩膜上形成具有宽度梯度的第一显影反应区；
    对位于所述第一显影反应区的所述第一掩膜进行显影，以在所述第一显影反应区形成具有宽度梯度的第一掩膜开口；
    在所述第一掩膜开口中电镀第一金属，以形成具有宽度梯度的第一栅线；
    根据所述第二掩膜的性质，对所述第二掩膜的局部区域进行曝光，以在所述第二掩膜上形成具有宽度梯度的第二显影反应区；
    对位于所述第二显影反应区的所述第二掩膜进行显影，以在所述第二显影反应区形成具有宽度梯度的第二掩膜开口；
    在所述第二掩膜开口中电镀第二金属，以形成具有宽度梯度的第二栅线；
    其中，所述第一金属和所述第二金属可以为相同的金属或者不同的金属。
  7. 根据权利要求6所述的栅线的制备方法，其特征在于：所述第一区域和所述第二区域均位于电池片的同一面上，或者所述第一区域和所述第二区域分别位于电池片的两个面上。
  8. 根据权利要求1所述的栅线的制备方法，其特征在于：在电池片的侧面涂布掩膜材料，使得所述掩膜材料固化形成掩膜。
  9. 根据权利要求1所述的栅线的制备方法，其特征在于：根据所述掩膜的 性质，对所述掩膜的局部区域进行曝光，以在所述掩膜上形成纵截面为梯形或阶梯形的显影反应区；
    对位于所述显影反应区的所述掩膜进行显影，以在所述显影反应区形成纵截面为梯形或阶梯形的掩膜开口；
    在所述掩膜开口中电镀金属，以形成纵截面为梯形或阶梯形的栅线。
  10. 根据权利要求9所述的栅线的制备方法，其特征在于：所述掩膜开口的纵截面为梯形，所述梯形的底角为45-89度。
  11. 根据权利要求1所述的栅线的制备方法，其特征在于：若在所述掩膜开口中电镀金属，未能形成纵截面为三角形或梯形的栅线；在所述栅线表面覆盖反射层或熔点低于300℃的合金焊层或者有机保护层，使得栅线的纵截面形成为三角形或梯形。
  12. 一种电池片的制备方法，其特征在于，所述电池片上的栅线采用以下步骤制备：
    S1、在电池片的正面和/或反面涂布掩膜材料，使得所述掩膜材料固化形成掩膜；
    S2、根据所述掩膜的性质，对所述掩膜的局部区域进行曝光，以在所述掩膜上形成具有宽度梯度的显影反应区；
    S3、对位于所述显影反应区的所述掩膜进行显影，以在所述显影反应区形成具有宽度梯度的掩膜开口；
    S4、在所述掩膜开口中电镀金属，以形成具有宽度梯度的栅线；
    S5、去除所述掩膜。
  13. 一种光伏电池，其特征在于：所述光伏电池包括电池片，以及设置在所述电池片上具有宽度梯度的栅线。
  14. 根据权利要求13所述的光伏电池，其特征在于：所述栅线的纵截面呈三角形或梯形或阶梯形。
  15. 根据权利要求13所述的光伏电池，其特征在于：所述栅线的表面还覆盖有亮锡或者亮银的反射层；或者
    所述栅线的表面覆盖有熔点低于300℃的合金焊层，所述合金焊层为锡与铅、铋、银、铜、铟和锌中的一种或几种形成；或者
    所述栅线的表面覆盖有有机保护层。
  16. 根据权利要求13所述的光伏电池，其特征在于：所述电池片的至少受光面设置有所述的栅线，或者所述电池片的两面均设置有所述的栅线。
  17. 根据权利要求13所述的光伏电池，其特征在于：
    所述栅线为多根，位于电池片同一面上的多根所述栅线的材料为不同金属和/或位于电池片不同面上的多根所述栅线的材料为不同金属。
  18. 根据权利要求13至17任一项所述的光伏电池，其特征在于：所述栅线的最小线宽小于50微米且大于或等于5微米。
PCT/CN2023/097324 2022-06-02 2023-05-31 一种栅线的制备方法、电池片的制备方法及光伏电池 WO2023232057A1 (zh)

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Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101807615A (zh) * 2009-02-18 2010-08-18 晶元光电股份有限公司 具有光收集效果电极结构的光伏元件
US20100252094A1 (en) * 2007-10-05 2010-10-07 Electronics And Telecommunications Research Institute High-Efficiency Solar Cell and Method of Manufacturing the Same
CN102820376A (zh) * 2012-08-16 2012-12-12 天津三安光电有限公司 一种太阳电池芯片电极的制备方法
WO2013030991A1 (ja) * 2011-08-31 2013-03-07 三洋電機株式会社 太陽電池及びその製造方法
CN103400869A (zh) * 2013-06-27 2013-11-20 北京大学深圳研究生院 一种太阳能电池正面电极和太阳能电池
CN103824894A (zh) * 2014-03-10 2014-05-28 余小翠 具有反光器的太阳能电池
CN110190140A (zh) * 2019-05-30 2019-08-30 江苏欧达丰新能源科技发展有限公司 可溶性掩膜真空镀制备光伏电池栅线电极的方法
CN217361599U (zh) * 2022-06-02 2022-09-02 苏州太阳井新能源有限公司 一种栅线及具备该栅线的光伏电池

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20100252094A1 (en) * 2007-10-05 2010-10-07 Electronics And Telecommunications Research Institute High-Efficiency Solar Cell and Method of Manufacturing the Same
CN101807615A (zh) * 2009-02-18 2010-08-18 晶元光电股份有限公司 具有光收集效果电极结构的光伏元件
WO2013030991A1 (ja) * 2011-08-31 2013-03-07 三洋電機株式会社 太陽電池及びその製造方法
CN102820376A (zh) * 2012-08-16 2012-12-12 天津三安光电有限公司 一种太阳电池芯片电极的制备方法
CN103400869A (zh) * 2013-06-27 2013-11-20 北京大学深圳研究生院 一种太阳能电池正面电极和太阳能电池
CN103824894A (zh) * 2014-03-10 2014-05-28 余小翠 具有反光器的太阳能电池
CN110190140A (zh) * 2019-05-30 2019-08-30 江苏欧达丰新能源科技发展有限公司 可溶性掩膜真空镀制备光伏电池栅线电极的方法
CN217361599U (zh) * 2022-06-02 2022-09-02 苏州太阳井新能源有限公司 一种栅线及具备该栅线的光伏电池

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