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CN-122028553-A - Solar cell, preparation method thereof and photovoltaic module

CN122028553ACN 122028553 ACN122028553 ACN 122028553ACN-122028553-A

Abstract

The invention relates to the technical field of photovoltaics, in particular to a solar cell, a preparation method thereof and a photovoltaic module, wherein the solar cell comprises: the battery comprises a battery matrix with a groove, a first transition layer, a second transition layer, a third transition layer, a TiN isolation layer and a grid line, wherein the first transition layer, the second transition layer, the third transition layer and the TiN isolation layer are sequentially formed in the groove, the Ni content of the first transition layer is more than or equal to the Ni content of the second transition layer, the Co content of the first transition layer is more than or equal to the Co content of the second transition layer, the third transition layer contains P, and the Ni content of the third transition layer is less than the Ni content of any one of the first transition layer and the second transition layer. The solar cell prepared by the preparation method can be used for forming a photovoltaic module, and the diffusion coefficient of grid line ions of the solar cell in a silicon wafer of a cell matrix is reduced so as to solve the problems of reduced minority carrier lifetime of the silicon wafer and loss of cell efficiency.

Inventors

  • Liao Hairui

Assignees

  • 通威太阳能（成都）有限公司

Dates

Publication Date
20260512
Application Date
20260210

Claims (10)

  1. 1. A solar cell, comprising: a battery matrix with a groove thereon; the first transition layer is formed at the bottom and the wall of the groove; a second transition layer formed on the first transition layer; a third transition layer formed on the second transition layer; a TiN isolation layer formed on the third transition layer; A gate line formed on the TiN isolation layer, wherein, The Ni content of the first transition layer is larger than or equal to the Ni content of the second transition layer, the Co content of the first transition layer is smaller than or equal to the Co content of the second transition layer, the third transition layer contains P, and the Ni content of the third transition layer is smaller than the Ni content of any one of the first transition layer and the second transition layer.
  2. 2. The solar cell according to claim 1, wherein the third transition layer has a P content higher than at least one of the first transition layer and the second transition layer, and/or, The roughness Ra of the groove wall of the groove is 5-10 nm, and/or, The battery matrix is TOPcon, the front surface and the back surface of the TOPcon battery are both provided with the grooves, wherein the groove bottoms of the grooves on the front surface of the TOPcon matrix are positioned on the boron doped polycrystalline silicon layer, the groove bottoms of the grooves on the back surface of the TOPcon matrix are positioned on the SiO 2 layer, or the battery matrix is HJT, and the groove bottoms of the grooves are positioned on the intrinsic amorphous silicon layer.
  3. 3. The solar cell according to claim 1, wherein the first transition layer has a Ni content of 70-80%, a Co content of 20-30%, the second transition layer has a Ni content of 50-70%, a Co content of 30-50%, the third transition layer has a P content of 10-15%, a Ni content of 30-40%, a Co content of 45-60%, and/or, The total thickness of the first transition layer, the second transition layer and the third transition layer is 20-50 nm, and/or, The thickness of the first transition layer is 5-10 nm, the thickness of the second transition layer is 10-20 nm, the thickness of the third transition layer is 5-10 nm, and/or, The thickness of the TiN isolation layer is 2-5 nm, and/or, The grooves have a width of 5-10 μm, and/or, The line width of the grid line is 8-12 mu m, and the height-width ratio is more than 3:1.
  4. 4. A method of manufacturing a solar cell according to any one of claims 1 to 3, comprising: A groove is formed in the battery matrix; forming a first transition layer on the bottom and the wall of the groove through magnetron sputtering; Forming a second transition layer on the first transition layer by electrodeposition; Forming a third transition layer on the second transition layer by electrodeposition; forming a TiN isolation layer on the third transition layer through atomic layer deposition; And electroplating to form a grid line on the TiN isolation layer.
  5. 5. The method of claim 4, further comprising forming the grooves on the battery substrate, performing low-temperature plasma etching to obtain grooves with a wall roughness Ra of 5-10 nm, and/or, The magnetron sputtering adopts a Ni-Co alloy target source, the sputtering power is 200-300W, the argon flow is 20-30sccm, and/or, The electrolyte for forming the second transition layer by electrodeposition contains NiSO with the molar concentration of 0.1-0.2mol/L 4 6H 2 O, 0.05-0.15mol/L CoSO 4 7H 2 O, 0.3-0.5mol/L H 3 BO 3 , the current density of the electrodeposited second transition layer is 0.5-1A/dm 2 , the deposition time is 10-20s, and/or, The electrolyte for forming the third transition layer by electrodeposition contains NiSO with the molar concentration of 0.1-0.2mol/L 4 6H 2 O, 0.05-0.15mol/L CoSO 4 7H 2 O, 0.3-0.5mol/L H 3 BO 3 and 0.01-0.03mol/L NaH 2 PO 2 , wherein the current density of the third transition layer formed by electrodeposition is 1-2A/dm 2 , the deposition time is 5-10s, and/or, The atomic layer deposition temperature is 80-120 ℃, the pressure of the deposition cavity is 100-500Pa, the precursors are TiCl 4 and NH 3 , and/or, The electrolyte for electroplating contains CuSO 4 、0.1-0.3mol/LH 2 SO 4 with the concentration of 0.8-1.2mol/L, polyethylene glycol with the concentration of 0.1-0.3g/L and thiourea derivatives with the concentration of 0.01-0.05g/L, wherein the electroplating is pulse electroplating with the temperature of 40-50 ℃, the pulse current density of 1-3A/dm 2 , the duty ratio of 30-50%, the pulse frequency of 50-100Hz and the deposition time of 30-60s, and/or, The preparation method of the solar cell further comprises ultraviolet light assisted annealing after the grid line is formed, and/or laser micro-cutting to remove the redundant copper layer at the edge of the grid line.
  6. 6. The method for preparing the solar cell according to claim 5, wherein the low-temperature plasma etching method specifically comprises the steps of introducing mixed gas of CF 4 and O 2 with a volume ratio of (2-4): 1 under the conditions that the vacuum degree is 0.5-1Pa and the radio frequency power is 100-200W, and etching for 10-30s.
  7. 7. The method of claim 5, wherein the atomic layer deposition method comprises depositing with TiCl 4 precursor pulse for 0.1-0.3s, introducing argon for 1-3s, depositing with NH 3 precursor pulse for 0.2-0.5s, introducing argon for 2-4s, and repeating the cycle.
  8. 8. The method according to claim 5, wherein the ultraviolet light assisted annealing comprises irradiating under ultraviolet light having a wavelength of 200-250nm and a radiation power density of 50-100mW/cm 2 in a protective atmosphere for 30-60s, and/or, The laser micro-cutting adopts green laser with the wavelength of 530-535nm and the power of 1-3W, and the cutting speed is 50-100 mm/s.
  9. 9. The method for producing a solar cell according to claim 4, wherein the entire process of the method for producing a solar cell is carried out at a temperature of <150 ℃, and/or, The preparation method of the solar cell further comprises alkaline washing and acid etching of the cell matrix before the groove is formed in the cell matrix, wherein the mass concentration of the alkaline washing NaOH solution is 5-10wt%, the alkaline washing temperature is 40-60 ℃ and the time is 30-60 seconds, the mass concentration of the acid etched HF is 5-10wt%, the acid etching temperature is room temperature and the time is 10-20 seconds, and/or, The method for forming the grooves comprises the step of forming the grooves on the battery substrate by using femtosecond laser with the wavelength of 1020-1040nm, the pulse width of 50-100fs and the power of 5-10W.
  10. 10. A photovoltaic module comprising the solar cell according to any one of claims 1 to 3, or the solar cell produced by the method of producing a solar cell according to any one of claims 4 to 9.

Description

Solar cell, preparation method thereof and photovoltaic module Technical Field The invention relates to the technical field of photovoltaics, in particular to a solar cell, a preparation method thereof and a photovoltaic module. Background One of the key processes for solar cell fabrication is to metalize it, including printing silver grid lines, or electroplating copper grid lines. The method for printing the silver grid line mainly comprises the steps of using a screen plate with a pattern (namely a grid line pattern), and accurately printing conductive silver paste on the surface of a battery matrix through meshes on the screen plate by the extrusion action of a scraping plate to form the required grid line. The method for electroplating the copper grid line mainly comprises the steps of depositing a seed copper layer on a battery substrate, realizing patterning by using photoresist to prepare a preplating groove, and electroplating in the preplating groove to form the copper grid line. Because the printed silver grid line has high cost, the line width is difficult to reduce, the shading is higher, and the photoelectric conversion efficiency is reduced, the related technology gradually adopts the electroplated grid line to replace the printed silver grid line, so that the cost is reduced, and the conductivity is improved. However, the method for electroplating copper grid lines and the solar cell manufactured by the method still have the problem that copper is easy to diffuse to the silicon substrate, so that the minority carrier lifetime of the silicon wafer is reduced, and the efficiency of the cell is lost. Disclosure of Invention The invention aims to provide a solar cell, a preparation method thereof and a photovoltaic module, wherein the solar cell prepared by the preparation method can be used for forming the photovoltaic module, and the diffusion coefficient of grid line ions (such as copper ions) of the solar cell prepared by the preparation method in a silicon wafer of a cell matrix is reduced, namely the grid line ions are not easy to diffuse into the silicon wafer of the cell matrix, so that the problems of reduced minority carrier lifetime of the silicon wafer and loss of cell efficiency can be improved. The invention is realized in the following way: In a first aspect, the present invention provides a solar cell comprising: a battery substrate, the battery substrate having a recess therein; The first transition layer is formed at the bottom of the groove and the groove wall; A second transition layer formed on the first transition layer; A third transition layer formed on the second transition layer; A TiN isolation layer formed on the third transition layer; a grid line formed on the TiN isolation layer, The first transition layer has a Ni content greater than or equal to a Ni content of the second transition layer, the first transition layer has a Co content less than or equal to a Co content of the second transition layer, the third transition layer contains P, and the third transition layer has a Ni content less than either one of the first transition layer and the second transition layer. In an alternative embodiment, the third transition layer has a P-content higher than at least one of the first transition layer and the second transition layer. In an alternative embodiment, the groove wall roughness Ra of the groove is 5-10 nm, and/or, The battery matrix is TOPcon, grooves are formed in the front face and the back face of the TOPcon battery, wherein the groove bottoms of the grooves in the front face of the TOPcon matrix are located on the boron doped polycrystalline silicon layer, the groove bottoms of the grooves in the back face of the TOPcon matrix are located on the SiO 2 layer, or the battery matrix is HJT, and the groove bottoms of the grooves are located on the intrinsic amorphous silicon layer. In an alternative embodiment, the grooves of the front side of TOPcon substrates have a groove depth of 70-95nm and the grooves of the back side of the TOPCon substrates have a groove depth of 100-120nm. In an alternative embodiment, the first transition layer has a Ni content of 70-80%, a Co content of 20-30%, the second transition layer has a Ni content of 50-70%, a Co content of 30-50%, the third transition layer has a P content of 10-15%, a Ni content of 30-40%, a Co content of 45-60%, and/or, The total thickness of the first transition layer, the second transition layer and the third transition layer is 20-50 nm, and/or, The thickness of the first transition layer is 5-10 nm, the thickness of the second transition layer is 10-20 nm, the thickness of the third transition layer is 5-10 nm, and/or, The thickness of the TiN isolation layer is 2-5 nm. In an alternative embodiment, the width of the groove is 5-10 μm, and/or the width of the grid line is 8-12 μm, and the aspect ratio is >3:1. In a second aspect, the present invention provides a method for producing a solar cell accordin