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Laser boron-doped back passivation solar cell and preparation method thereof

A solar cell and boron doping technology, applied in the field of solar cells, can solve the problems of decreased passivation capability, lower back interface state, lower cell conversion efficiency, etc.

Pending Publication Date: 2020-10-23
TONGWEI SOLAR ENERGY MEISHAN CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

On the back of the battery, an insulating passivation layer is deposited to reduce the interface state on the back, improve the passivation effect, extend the light path, improve the long-wave response and short-circuit current, and then selectively etch away part of the passivation by laser etching. layer, so that the silicon layer is exposed, and then the back electric field aluminum paste is printed on the laser etching area to form direct contact with the silicon layer, so as to realize electrical conduction; therefore, the passivation ability of the back laser etching area is partially removed due to the removal The decline has directly affected the effect of the overall back passivation, resulting in a reduction in the conversion efficiency of the battery

Method used

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  • Laser boron-doped back passivation solar cell and preparation method thereof
  • Laser boron-doped back passivation solar cell and preparation method thereof

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Embodiment 1

[0034] refer to figure 2 , the present embodiment provides a laser boron-doped back-passivated solar cell, comprising P-type silicon 1, and the front side of the P-type silicon 1 is sequentially provided with a phosphorus-doped layer 2 (N+ layer), SiN x The anti-reflection layer 3 and the Ag grid finger electrode 5 are passivated on the front side, and a heavily doped silicon layer 4 (N++ layer) is also provided on the front side of the P-type silicon 1, and the Ag grid finger electrode 5 is connected with the heavily doped silicon layer 4 and The upper surface of the P-type silicon 1 is connected, and the back of the P-type silicon 1 is sequentially provided with AlO x Passivation layer 6, SiN x The back passivates the anti-reflection layer 7 and the Al gate finger electrode 9, and the back side of the P-type silicon 1 is also provided with a heavily doped region 8, and the heavily doped region 8 includes a boron heavily doped layer 801 (P++ layer) and a local Contact the ...

Embodiment 2

[0036] This embodiment provides a method for preparing a laser boron-doped back passivated solar cell, comprising the following steps:

[0037] (1) Alkali texture is used to remove the damaged layer of the silicon wafer in the tank and texture it to form a pyramid texture with a height of 0.5 μm-5 μm;

[0038] (2) Using phosphorus oxychloride (POCl 3 ) high-temperature diffusion, the reaction temperature is 750-850°C, and the reaction time is 30-60min, forming a phosphorus-doped layer on the surface of the silicon wafer, that is, a P-doped N+ emitter junction;

[0039] (3) Laser doping is used to form a heavily doped silicon layer (N++ layer);

[0040] (4) Using wet etching process, with HNO 3 / HF mixed solution, remove the P-doped N+ junction on the back of the silicon wafer, and polish the back, high temperature annealing, the annealing reaction temperature is 750-850 °C;

[0041](5) AlO is sequentially deposited on the back of the silicon wafer by atomic layer deposition...

Embodiment 3

[0047] This embodiment is preferred on the basis of embodiment 2, the AlO x layer was prepared using TMA and O 2 / N 2 A mixed gas of O, the reaction temperature is 200-350°C, and the thickness is 5-15nm;

[0048] The SiN x layer using SiH 4 and NH 3 mixed gas, the reaction temperature is 300-550°C, the thickness is 70-110nm, and the refractive index is 1.9-2.2. The SiN x Layers can be single or double or triple layered.

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Abstract

The invention discloses a laser boron-doped back passivation solar cell and a preparation method thereof, aims at improving a back passivation structure of a solar cell in the prior art, and relates to the technical field of solar cells. The solar cell comprises P-type silicon; a phosphorus doping layer, a front passivation antireflection layer and an Ag gate finger electrode are sequentially arranged on the front surface of the P-type silicon upwards; a passivation layer, a back passivation antireflection layer and an Al gate finger electrode are sequentially arranged on the back surface of the P-type silicon downwards, a heavily doped region is further arranged on the back surface of the P-type silicon, the heavily doped region comprises a boron heavily doped layer and a local contact aluminum doped layer, and the Al gate finger electrode is connected with the lower surface of the P-type silicon through the heavily doped region; by forming the heavily doped region on the back surfaceof the cell, the composite loss of the metal contact region can be effectively reduced, the contact resistance can be reduced, the passivation capability can be enhanced, a relatively high short-circuit current can be maintained, the open-circuit voltage can be increased, and a filling factor can be improved, so that the solar cell with high conversion efficiency and high stability can be realized.

Description

technical field [0001] The invention relates to the technical field of solar cells, in particular to a laser boron-doped back passivated solar cell and a preparation method thereof. Background technique [0002] At present, solar cells mainly use crystalline silicon as the base material. Due to the periodic damage on the surface of the silicon wafer, a large number of dangling bonds will be generated, so that there are a large number of defect energy levels in the band gap on the crystal surface; in addition, the position The deposition of faults, chemical residues, and surface metals will all introduce defect levels, making the surface of the silicon wafer a recombination center, resulting in a large surface recombination rate, which in turn limits the conversion efficiency. [0003] Compared with conventional batteries, the main advantage of back-passivated batteries is to reduce the interface state on the back of the battery sheet, improve passivation ability, and increas...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01L31/0216H01L31/0224H01L31/0288H01L31/06H01L31/18
CPCH01L31/02168H01L31/022425H01L31/0288H01L31/06H01L31/1804H01L31/1868Y02E10/547Y02P70/50
Inventor 张鹏朱波何宇眭山
Owner TONGWEI SOLAR ENERGY MEISHAN CO LTD
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