CN216698383U

CN216698383U - Ingot single crystal and MWT battery structure

Info

Publication number: CN216698383U
Application number: CN202122656447.2U
Authority: CN
Inventors: 罗西佳; 王伟; 吴仕梁; 张凤鸣
Original assignee: Nanjing Rituo Photovoltaic New Energy Co ltd
Current assignee: Jiangsu Sunport Power Corp Ltd
Priority date: 2021-11-02
Filing date: 2021-11-02
Publication date: 2022-06-07
Anticipated expiration: 2031-11-02

Abstract

The utility model provides an ingot single crystal and MWT battery structure, which sequentially comprises a front antireflection film, an SiON laminated film, a front diffusion layer, a front black silicon small suede, a single crystal silicon substrate and a back electric field from top to bottom, wherein a front electrode and a back electrode are respectively arranged on two sides of the single crystal silicon substrate, the front electrode is embedded into the front antireflection film, the SiON laminated film and the front diffusion layer, and the back electrode is embedded into the back electric field; a through hole is formed in the center of the monocrystalline silicon substrate, one end of the through hole is sealed through the front electrode, and hole plugging slurry is filled in the through hole. The silicon wafer module has the advantage of low cost of the ingot casting monocrystalline silicon wafer, can be compatible with the silicon wafer with the thickness of less than 150 microns, can improve the battery efficiency while solving the appearance problem, and can improve the current and the battery efficiency and the comprehensive generating capacity of the module.

Description

Ingot single crystal and MWT battery structure

Technical Field

The utility model relates to the technical field of solar cell production, in particular to a structure of an ingot single crystal and MWT cell.

Background

The traditional crystal silicon mainly comprises a czochralski single crystal and an ingot casting polycrystal, wherein a czochralski single crystal silicon ingot has less dislocation, low impurity concentration and longer minority carrier lifetime, but the problem of low raw material utilization rate and low productivity exist in the square cutting process; the yield of the ingot polycrystal is high, but the dislocation and impurity concentration are high, and the minority carrier lifetime is low. The ingot single crystal combines the advantages of low dislocation impurity concentration of the Czochralski single crystal and high material utilization rate of the cast polycrystal, has great significance for reducing the power cost of photovoltaic power generation, and has wide market prospect.

At present, the PERC technology is comprehensively upgraded in the market, and polycrystalline silicon chips exit the stage; the existing Czochralski single crystal silicon wafer of 5 yuan/wafer still has short supply, compared with the ingot casting single crystal, the cost can be reduced by 20 percent, the problem of shortage of raw materials can be solved, the cost of the silicon wafer is saved, the requirement on silicon materials is low, and the silicon wafer with large size can be produced. However, the main reasons why the ingot casting monocrystalline silicon piece cannot be widely popularized are that the ingot casting monocrystalline silicon piece has crystal flowers, color difference caused by the problem of crystal boundaries and the problem of component appearance, so that the component can only be applied to power stations without requirements on appearance in remote areas.

The MWT battery has the advantages of high conversion efficiency, low temperature coefficient, low attenuation, good low-light property and the like, but the cost is higher at present and the cost performance is relatively poorer.

SUMMERY OF THE UTILITY MODEL

The utility model provides an ingot single crystal and MWT battery structure for solving the problems in the prior art, which has the advantage of low cost of ingot single crystal silicon wafers, can be compatible with silicon wafers with the thickness of less than 150 microns, can improve the battery efficiency while solving the appearance problem, and can improve the current and the battery efficiency and the comprehensive power generation capacity of a component.

The utility model provides an ingot single crystal and MWT battery structure, which sequentially comprises a front antireflection film, an SiON laminated film, a front diffusion layer, a front black silicon small suede, a single crystal silicon substrate and a back electric field from top to bottom, wherein a front electrode and a back electrode are respectively arranged on two sides of the single crystal silicon substrate, the front electrode is embedded into the front antireflection film, the SiON laminated film and the front diffusion layer, and the back electrode is embedded into the back electric field; a through hole is formed in the center of the monocrystalline silicon substrate, one end of the through hole is sealed through the front electrode, and hole plugging slurry is filled in the through hole.

In a further improvement, a front surface oxidation film is arranged between the front surface antireflection film and the SiON laminated film and a front surface diffusion layer, and a back surface passivation film is arranged between the back surface electric field and the monocrystalline silicon substrate.

The utility model provides a preparation method of an ingot single crystal and MWT battery structure, which comprises the following steps:

s01: carrying out laser drilling on the ingot casting monocrystalline silicon substrate;

s02: cleaning and polishing a monocrystalline silicon substrate: texturing and cleaning a monocrystalline silicon substrate, removing a mechanical damage layer and pollutants on the surface of the silicon, and forming a pyramid textured surface;

s03: black silicon etching is carried out on the basic pyramid textured surface to form a small front black silicon textured surface;

s04: diffusing the front black silicon small suede to form a diffusion layer;

s05: removing PSG, performing edge isolation, and performing alkali polishing on the back surface;

s06: depositing an antireflection film and a SiON laminated film on the front surface of the monocrystalline silicon substrate:

s07: screen printing front conductive silver paste, printing hole plugging paste on the back, printing a back field pattern on the back, and sintering;

s08: and carrying out light injection or electric injection process to finally finish the preparation of the battery.

Further improved, between the step S04 and the step S05, laser SE is performed on the surface of the diffusion layer, surface thermal oxidation is performed, between the step S05 and the step S06, back passivation film deposition is performed on the back surface of the monocrystalline silicon substrate, annealing is performed, and between the step S06 and the step S07, laser windowing is performed on the back surface of the monocrystalline silicon substrate.

In a further improvement, the ingot single crystal silicon substrate in step S01 is a P-type or N-type silicon wafer.

In a further improvement, the black silicon etching in step S03 is dry or wet black silicon etching.

In a further improvement, the anti-reflection film and SiON laminated film in step S06 is composed of two or more film layers.

Further improved, the surface of the diffusion layer is subjected to surface thermal oxidation to form single-sided oxidation or double-sided oxidation.

In a further improvement, the back passivation film is composed of two or more film layers.

The utility model has the beneficial effects that:

1. the battery has the advantage of low cost of ingot casting monocrystalline silicon wafers, can be compatible with silicon wafers with the thickness of less than 150 microns, can further reduce the cost, conforms to the trend of market flaking, and can also be applied to flexible components;

2. the battery has a dark appearance of a black silicon + SiON laminated film structure, can effectively shield the lightening of crystal boundary, reduce surface reflection, increase light absorption, solve the appearance problem and simultaneously improve the battery efficiency;

3. the design combined with the MWT technology can reduce the grid line shielding to the greatest extent, further increase the light absorption, improve the current and the battery efficiency and improve the comprehensive power generation capacity of the component.

Drawings

FIG. 1 is a schematic structural diagram of an ingot single crystal black silicon + SiON laminated film + MWT battery.

FIG. 2 is a schematic structural diagram of an ingot single crystal black silicon + SiON laminated film + MWT-PERC battery.

Detailed Description

The utility model will be further described with reference to the accompanying drawings.

The first embodiment is as follows:

the utility model provides an ingot casting single crystal black silicon + SiON laminated film + MWT battery structure, which sequentially comprises a front side antireflection film, an SiON laminated film 4, a front side diffusion layer 3, a front side black silicon small suede 2, a single crystal silicon substrate 1 and a back electric field 7 from top to bottom as shown in figure 1, wherein a front side electrode 5 and a back electrode 8 are respectively arranged on two sides of the single crystal silicon substrate, the front side electrode is embedded in the front side antireflection film, the SiON laminated film and the front side diffusion layer, and the back electrode is embedded in the back electric field; a through hole is formed in the center of the monocrystalline silicon substrate, one end of the through hole is sealed through the front electrode, and hole plugging slurry 6 is filled in the through hole.

Example two:

the utility model provides an ingot casting single crystal black silicon + SiON laminated film + MWT + PERC battery structure, as shown in figure 2, comprising a front antireflection film, an SiON laminated film 4, a front oxidation film 9, a front diffusion layer 3, a front black silicon small suede 2, a single crystal silicon substrate 1, a back passivation film 10 and a back electric field 7, wherein the two sides of the single crystal silicon substrate are respectively provided with a front electrode 5 and a back electrode 8, the front electrode is embedded into the front antireflection film, the SiON laminated film and the front diffusion layer, and the back electrode is embedded into the back electric field; a through hole is formed in the center of the monocrystalline silicon substrate, one end of the through hole is sealed through the front electrode, and hole plugging slurry 6 is filled in the through hole.

The utility model also provides a preparation method of the MWT + PERC/MWT ingot casting single crystal battery, which is characterized in that the high-efficiency battery is prepared by adopting the technologies of black silicon etching, SiON film deposition, MWT and PERC, a new technical route of the ingot casting single crystal battery is created, and the specific technical route is as follows:

s01, carrying out laser drilling on the ingot monocrystalline silicon wafer;

s02 silicon wafer cleaning and polishing: texturing and cleaning the P-type monocrystalline silicon substrate, removing a mechanical damage layer and pollutants on the surface of the silicon, and forming a pyramid textured surface;

s03, black silicon etching is carried out on the basic pyramid suede to form a small suede;

s04, diffusing the front surface to form a diffusion layer;

s05, carrying out laser SE on the front surface;

carrying out surface thermal oxidation on the S06 silicon wafer;

s07 removing PSG to carry out edge isolation and carrying out back alkali polishing;

depositing a back passivation film on the back surface of S08, and annealing;

s09 front surface is deposited with anti-reflection film + SiON laminated film:

s10 laser windowing on the back;

s11 screen printing front conductive silver paste, printing hole plugging paste on the back (printing the hole plugging paste into holes which are previously drilled on a silicon wafer by laser from the back), printing a back field pattern on the back and sintering;

and S12, performing light injection or electric injection process, and finally completing the preparation of the battery.

Further: s01 can be an ingot single crystal P-type or N-type silicon wafer; s03 is a small suede formed by dry or wet black silicon etching; s04 may be a P-type or N-type diffusion; s06 can be single-sided oxidation or double-sided oxidation; the back passivation film in the S08 can be composed of two or more film layers; the front antireflective film + SiON laminated film in S09 may be composed of two or more layers.

Wherein S05, S06, S08 and S10 in the technical route are MWT and PERC superposition technical steps. If the technical scheme of ingot single crystal and MWT battery is selected, the technical route is as follows: s01, S02, S03, S04, S07, S09, S08 and S11.

While the utility model has been described in terms of its preferred embodiments, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the utility model.

Claims

1. The utility model provides an ingot casting single crystal adds MWT battery structure which characterized in that: the single crystal silicon substrate comprises a front antireflection film, an SiON laminated film, a front diffusion layer, a front black silicon small suede, a single crystal silicon substrate and a back electric field in sequence from top to bottom, wherein a front electrode and a back electrode are respectively arranged on two sides of the single crystal silicon substrate, the front electrode is embedded into the front antireflection film, the SiON laminated film and the front diffusion layer, and the back electrode is embedded into the back electric field; a through hole is formed in the center of the monocrystalline silicon substrate, one end of the through hole is sealed through the front electrode, and hole plugging slurry is filled in the through hole.

2. The ingot single crystal plus MWT cell structure of claim 1, wherein: a front surface oxidation film is arranged between the front surface antireflection film and the SiON laminated film and between the front surface diffusion layer, and a back surface passivation film is arranged between the back surface electric field and the monocrystalline silicon substrate.