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EP-4243089-B1 - METHOD FOR MANUFACTURING SOLAR CELL, SOLAR MODULE, AND POWER GENERATION SYSTEM

EP4243089B1EP 4243089 B1EP4243089 B1EP 4243089B1EP-4243089-B1

Inventors

  • WANG, YONGQIAN
  • XU, WENLI
  • ZHU, WEI
  • CHEN, GANG

Dates

Publication Date
20260513
Application Date
20220707

Claims (20)

  1. A method for manufacturing a solar cell, comprising: step S1: perforating a film layer in a first region (100) and/or a second region (200) of a solar cell where an electrode is to be disposed, thus forming a plurality of holes or grooves (2); wherein the solar cell comprises a silicon substrate; step S2: growing a seed layer (1) on the solar cell, wherein the seed layer (1) comes into conductive contact with the first region (100) and/or the second region (200) through the plurality of holes or grooves (2) in step S1; the seed layer (1) comprises a main component and an improved component; the main component is Al in an amount of greater than or equal to 70 wt. % of the seed layer; the improved component comprises any one or more of Mo, Ni, Ti, W, Cr, Mn, Pd, Bi, Nb, Ta, Pa, and V in an amount of less than or equal to 30 wt. % of the seed layer (1); and step S3: horizontally transporting a to-be-electroplated solar cell, wherein a cathode electroplating brush (11) is in contact with the seed layer (1) on the horizontally transmitted solar cell, to form a cathode of an electroplating system on the seed layer (1), an anode terminal is disposed in an electroplating liquid in an electroplating bath (12), and a moving mechanism disposed in the electroplating bath (12) drives the solar cell to move from an inlet to an outlet of the moving mechanism of the solar cell, thus achieving electroplating of the solar cell during energization and the horizontal transmission.
  2. The method for manufacturing a solar cell according to claim 1, wherein the first region (100) or/and the second region (200) is/are covered with a tunnel oxide layer and a polysilicon layer.
  3. The method for manufacturing a solar cell according to claim 1, wherein the seed layer (1) is grown on the solar cell by means of physical vapor deposition.
  4. The method for manufacturing a solar cell according to claim 3, wherein in step S2, a transparent conductive oxide (TCO) thin film is grown by using a physical vapor deposition method before the seed layer (1) is grown.
  5. The method for manufacturing a solar cell according to any of claims 1-4, wherein when the first region (100) and the second region (200) on the solar cell both exist on a back side of a silicon wafer, the method further comprises: step A1: manufacturing a mask in an electroplated electrode region on an electroplated sample, etching the electroplated sample, and forming insulation between electroplated electrodes in the first region (100) and the second region (200).
  6. The method for manufacturing a solar cell according to any of claims 1-4, wherein when the first region (100) and the second region (200) on the solar cell both exist on a back side of a silicon wafer, between step S2 and step S3, the method further comprises: forming a mask on the seed layer (1), to achieve physical isolation of electroplating layers in the first region (100) and the second region (200).
  7. The method for manufacturing a solar cell according to claim 6, wherein after step S3, the method further comprises: removing the mask layer on the seed layer (1), and then performing wet chemical etching to remove the seed layer (1), to form insulation between electroplated electrodes in the first region (100) and the second region (200).
  8. The method for manufacturing a solar cell according to claim 7, wherein the TCO thin film is also removed during removal of the seed layer (1) by means of the wet chemical etching.
  9. The method for manufacturing a solar cell according to any of claims 1-4, wherein when the first region (100) and the second region (200) on the solar cell both exist on a back side of a silicon wafer, after step S2, the method further comprises: step B1: forming a mask on the seed layer (1), and then performing wet chemical etching to realize insulation between seed layers in the first region (100) and the second region (200); and step B2: removing the mask on the seed layer (1).
  10. The method for manufacturing a solar cell according to any of claims 1-4, wherein when the first region (100) and the second region (200) on the solar cell both exist on a back side of a silicon wafer, in step S2, a mask is used on the solar cell to form a patterned electroplating seed layer, to realize insulation between seed layers in the first region (100) and the second region (200).
  11. The method for manufacturing a solar cell according to any of claims 1-4, wherein the solar cell where an electrode is to be disposed is manufactured by using the following steps: step L1: texturing a surface of a silicon wafer; step L2: depositing a tunnel oxide layer on a back side of the silicon wafer, and then depositing first doped polysilicon having a first polarity on the tunnel oxide layer; step L3: depositing a first mask on the first doped polysilicon; step L4: retaining the first mask predisposed in the first region (100) on the back side of the silicon wafer, and removing the first mask predisposed in the second region (200) on the back side of the silicon wafer; step L5: removing the first doped polysilicon and the tunnel oxide layer deposited in the second region (200), and then manufacturing a second mask in the second region (200) again; step L6: depositing the tunnel oxide layer in the second region (200), and then depositing second doped polysilicon having a second polarity on the tunnel oxide layer in the second region (200); step L7: manufacturing a third mask on the second doped polysilicon deposited in the second region (200); step L8: retaining the third mask in a protruding portion in the second region (200), and removing the third mask from a recessed portion in the second region (200); wherein the recessed portion is indented from the protruding portion toward a front side of the silicon wafer; step L9: removing, by using a wet chemical method, the second mask deposited in the first region (100), a material layer above the second mask, and the tunnel oxide layer and the second doped polysilicon deposited in the recessed portion on the back side of the silicon wafer; and step L10: performing a double-sided coating on the silicon wafer to obtain the solar cell where the electrode is to be disposed.
  12. The method for manufacturing a solar cell according to claim 1, wherein the improved component further comprises a non-metallic composition.
  13. The method for manufacturing a solar cell according to claim 1, wherein the seed layer (1) is formed on the silicon substrate by using physical vapor deposition manufacturing method, or screen printing manufacturing method, or chemical vapor deposition manufacturing method, or electroplating manufacturing method, or chemical plating manufacturing method, or ion plating manufacturing method.
  14. The method for manufacturing a solar cell according to claim 13, wherein the physical vapor deposition comprises sputtering and evaporation.
  15. The method for manufacturing a solar cell according to claim 1, wherein the seed layer (1) is also covered with a conductive layer (5).
  16. The method for manufacturing a solar cell according to claim 15, wherein the conductive layer (5) comprises any one or more of Cu, Ag, and Al.
  17. The method for manufacturing a solar cell according to claim 15, wherein a method for growing the conductive layer (5) on the seed layer (1) comprises any of electroplating, physical vapor deposition, screen printing, and chemical plating.
  18. The method for manufacturing a solar cell according to claim 15, wherein an upper portion of the conductive layer (5) is covered with a protective layer (6).
  19. The method for manufacturing a solar cell according to claim 18, wherein the protective layer (6) is an Sn layer or an Ag layer.
  20. The method for manufacturing a solar cell according to claim 18 or 19, wherein the protective layer (6) is grown on the conductive layer (5) by electroplating or chemical plating.

Description

The disclosure relates to the field of solar cells, and more particularly, to a method for manufacturing a solar cell, a solar module, and a power generation system. In the prior art, an electrode manufacturing method of a solar cell generally includes the following steps. Step 1: texturing a surface of an N-type silicon wafer by using a wet chemical method;Step 2: making an emitter on a front side of the N-type silicon wafer;Step 3: depositing a tunnel oxide layer on a back side of the N-type silicon wafer, and then depositing doped polysilicon on the tunnel oxide layer;Step 4: performing double-sided coating on the N-type silicon wafer;Step 5: performing film perforation on the front side and the back side of the N-type silicon wafer by laser to form an electrode predisposing region and an electroplating needle press-in area at the same time; andStep 6: Clamping, by using an electroplated electrode, the electroplating needle-contacted area on the front side and the back side of a cell for groove-shaped electroplating. The width of the electrode manufactured by using the above method is limited by a film perforation size by laser. The film perforation by laser introduces some damage, and therefore a larger film perforation size by laser leads to more serious laser damage. In addition, when the electrode is on the front side, incidence of sunlight is blocked, and if the electrode width is excessively wide, conversion efficiency of the cell is reduced. However, a small film perforation size by laser may also cause problems, including: 1) A smaller electrode width easily causes the finger to fall off. 2) A smaller electrode width leads to larger line resistance of the electrode, which affects the conversion efficiency of the cell. Ideally, a larger electrode width leads to smaller line resistance of the solar cell, which is more conducive to enhancement of efficiency of the solar cell. Therefore, how to solve a contradiction between the width of the electrode manufactured by using the above method and the film perforation size by laser becomes a problem to be urgently solved in the technical field of manufacturing the solar cell. Moreover, the above existing electrode manufacturing method adopts a vertical electroplating method. The vertical electroplating cannot electroplate the solar cell in a streamlined manner. Therefore, the electroplating efficiency is low compared with horizontal electroplating, and it is difficult to satisfy the requirement for scale electroplating of the solar cell. In addition, an electrode pressure point during the vertical electroplating blocks an electroplating reaction, which affects the appearance and conversion efficiency of the cell. US 2008/128019 A1 discloses growing a seed layer 321 that includes a first layer and a second copper-containing layer. The first layer contains one or more metals or metal alloys selected from molybdenum (Mo), nickel (Ni), titanium (Ti), tungsten (W), and tantalum (Ta). The second copper-containing layer is a substantially pure layer or an alloy that contains aluminium (Al). The disclosure provides a method for manufacturing a solar cell, a solar module, and a power generation system, so as to ensure an electrode width of a solar cell, prevent a finger from falling off, and satisfy a requirement for scale electroplating without affecting a film perforation size. To achieve the objective, the disclosure adopts the following technical solution. A method for manufacturing a solar cell is provided, the method comprising: step S1: perforating a film layer in a first region and/or a second region of a solar cell where an electrode is to be disposed, thus forming a plurality of holes or grooves, wherein the solar cell comprises a silicon substrate;step S2: growing a seed layer on the solar cell, where the seed layer comes into conductive contact with the first region and/or the second region through the plurality of holes or grooves in step S1; the seed layer comprises a main component and an improved component; the main component is Al in an amount of greater than or equal to 70 wt. % of the seed layer; the improved component comprises any one or more of Mo, Ni, Ti, W, Cr, Mn, Pd, Bi, Nb, Ta, Pa, and V in an amount of less than or equal to 30 wt. % of the seed layer; andstep S3: horizontally transporting a to-be-electroplated solar cell, where a cathode electroplating brush is in contact with the seed layer on the horizontally transmitted solar cell, to form a cathode of an electroplating system on the seed layer, an anode terminal is disposed in an electroplating liquid in an electroplating bath, and a moving mechanism disposed in the electroplating bath drives the solar cell to move from an inlet to an outlet of the moving mechanism of the solar cell, thus achieving electroplating of the solar cell during energization and the horizontal transmission. Preferably, the first region and the second region are covered with a tunnel oxide layer and a polysi