CN117976770A - Photovoltaic cell preparation method, photovoltaic cell and photovoltaic module - Google Patents

Abstract

The invention discloses a preparation method of a photovoltaic cell, the photovoltaic cell and a photovoltaic module, wherein the preparation method comprises the following steps: providing a phosphorus-diffused silicon substrate, and cutting a first surface of the silicon substrate along a direction perpendicular to the thickness of the silicon substrate to obtain a cut silicon substrate; etching the first surface of the cut silicon substrate to obtain an etched silicon substrate; the outer surface of the etched silicon substrate is a selective emitter; passivating one side of the selective emitter far away from the first surface and the cutting surface to obtain a silicon substrate with a passivation layer; after the phosphorus diffusion process for preparing the photovoltaic cell, the photovoltaic cell is cut into half pieces, and then etching and passivation are carried out, so that the edge cutting damage of the photovoltaic cell can be reduced, the surface recombination of a cutting surface is reduced, the efficiency is increased, and the influence on the productivity by slicing before texturing is small.

Description

Photovoltaic cell preparation method, photovoltaic cell and photovoltaic module

Technical Field

The present invention relates to the field of photovoltaic technology, and more specifically, to a method for preparing a photovoltaic cell, a photovoltaic cell and a photovoltaic module.

Background technique

As the global economic activities have an increasing demand for energy, solar energy has become an inexhaustible renewable energy source for mankind. Solar energy is fully clean, absolutely safe, relatively extensive and maintenance-free. Therefore, photovoltaic module technology that uses solar energy to generate electricity has developed rapidly.

In the production process of photovoltaic modules, the photovoltaic cells need to be cut in half for subsequent production. However, the actual cutting will cause molten silicon to appear on the cut surface and surrounding surface of the photovoltaic cells. Slicing will cause significant damage to the cut edges of the photovoltaic cells, increase recombination, and cause a significant reduction in efficiency.

Summary of the invention

In view of this, the present invention provides a method for preparing a photovoltaic cell, a photovoltaic cell and a photovoltaic module, which can reduce cutting damage at the edge of the photovoltaic cell, reduce surface recombination of the cut surface, and increase efficiency.

In a first aspect, the present application provides a method for preparing a photovoltaic cell, comprising:

Providing a phosphorus-diffused silicon substrate, wherein the phosphorus-diffused silicon substrate has a first surface;

Cutting the first surface of the silicon substrate along a direction perpendicular to the thickness of the silicon substrate to obtain the cut silicon substrate;

Etching the first surface of the cut silicon substrate to obtain the etched silicon substrate; wherein the outer surface of the etched silicon substrate is a selective emitter;

The cut silicon substrate has a cut surface, and the side of the selective emitter away from the first surface and the cut surface are passivated to obtain the silicon substrate with a passivation layer.

Optionally, the cutting method of the silicon substrate includes: laser cutting, abrasive cutting and diamond cutting.

Optionally, when the silicon substrate is cut by laser cutting, the laser runs in a direction perpendicular to the thickness direction of the silicon substrate.

Optionally, when the cutting method of the silicon substrate is laser cutting, the laser power range of the laser cutting is 15-20W; the laser frequency range of the laser cutting is 100-150kHz; the laser running speed range of the laser cutting is 400-500mm/s.

Optionally, etching the first surface of the cut silicon substrate includes:

The first surface of the cut silicon substrate is etched using a chain cleaning machine; wherein the chain cleaning machine includes a conveyor belt, and the cut silicon substrate is placed on the conveyor belt for etching; the first surface of the silicon substrate faces one side of the conveyor belt, and the cut surface of the silicon substrate faces the moving direction of the conveyor belt.

Optionally, the step of providing a phosphorus-diffused silicon substrate further comprises:

obtaining the silicon substrate;

Performing boron diffusion on the first surface of the silicon substrate to obtain the silicon substrate having a selective emitter;

The silicon substrate after boron diffusion has a second surface arranged opposite to the first surface, and a tunneling oxide layer is formed on the second surface of the silicon substrate;

Depositing an amorphous silicon layer on a side of the tunnel oxide layer away from the silicon substrate;

Phosphorus is diffused on a side of the amorphous silicon layer away from the tunnel oxide layer to form a doped conductive layer.

Optionally, the side of the selective emitter away from the first surface is passivated to obtain the silicon substrate having a passivation layer, and then the method further includes:

The passivated silicon substrate has a second surface corresponding to the first surface; the first surface and the second surface of the silicon substrate having the passivation layer are coated to obtain the silicon substrate having the first anti-reflection layer and the second anti-reflection layer;

A first electrode is formed on the anti-reflection layer on the first surface, and a second electrode is formed on the anti-reflection layer on the second surface.

In a second aspect, the present application also provides a photovoltaic cell, comprising a photovoltaic cell prepared by the method for preparing a photovoltaic cell described in any of the above items; the photovoltaic cell comprises the silicon substrate, the silicon substrate has a cutting surface, and the cutting surface is sequentially stacked with a passivation layer and a first anti-reflection layer in a direction away from the silicon substrate.

Optionally, the length of the passivation layer on the cutting surface along the thickness direction of the silicon substrate is smaller than the thickness of the photovoltaic cell along the thickness direction of the silicon substrate; the length of the first anti-reflection layer on the cutting surface along the thickness direction of the silicon substrate is smaller than the thickness of the photovoltaic cell along the thickness direction of the silicon substrate.

In a third aspect, the present application also provides a photovoltaic module, comprising a laminate and a frame wrapped around the laminate, wherein the laminate comprises a front panel, a first packaging film, a photovoltaic cell, a second packaging film and a back panel arranged in sequence, and the photovoltaic cell comprises the above-mentioned photovoltaic cell.

Compared with the prior art, the photovoltaic cell preparation method, photovoltaic cell and photovoltaic module provided by the present invention achieve at least the following beneficial effects:

The invention provides a preparation method of a photovoltaic cell, a photovoltaic cell and a photovoltaic module. The preparation method comprises: providing a silicon substrate after phosphorus diffusion, cutting a first surface of the silicon substrate along a direction perpendicular to the thickness of the silicon substrate to obtain a cut silicon substrate; etching the first surface of the cut silicon substrate to obtain an etched silicon substrate; the outer surface of the etched silicon substrate is a selective emitter; passivating a side of the selective emitter away from the first surface and a cut surface to obtain a silicon substrate with a passivation layer; cutting the photovoltaic cell into half slices after the phosphorus diffusion process in the preparation of the photovoltaic cell, and then etching and passivating. The etching and passivation process can reduce the edge cutting damage of the photovoltaic cell, reduce the surface recombination of the cut surface, and increase the efficiency, and the influence on the production capacity is smaller than that of slicing before texturing.

Of course, any product implementing the present invention does not necessarily need to achieve all of the technical effects described above at the same time.

Further features and advantages of the present invention will become apparent from the following detailed description of exemplary embodiments of the present invention with reference to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

FIG1 is a schematic diagram of the ideal and actual interface for cutting photovoltaic cells;

FIG2 is a flow chart of a method for preparing a photovoltaic cell provided in an embodiment of the present invention;

FIG3 is a flow chart of the preparation of photovoltaic cells in the experimental group of the present invention;

FIG4 is a schematic diagram of the structure of a chain cleaning machine for etching a silicon substrate according to the present invention;

FIG5 is a flow chart of the preparation of photovoltaic cells of the control group of the present invention;

FIG6 is a PL (photoluminescence) imaging result of the photovoltaic cell of the experimental group in the present invention;

FIG7 is a PL imaging result of a photovoltaic cell of a control group in the present invention;

FIG8 is a flow chart of an optional implementation method of obtaining a silicon substrate after phosphorus diffusion provided by an embodiment of the present invention;

9 is a flow chart of forming a first anti-reflection layer and a first electrode and a second electrode of a second anti-reflection layer on a surface of a silicon substrate having a passivation layer, provided by an embodiment of the present invention;

FIG10 is a schematic diagram of the structure of a photovoltaic cell provided by an embodiment of the present invention;

FIG11 is a partial enlarged view of point A in FIG10;

FIG. 12 is a schematic diagram of the structure of a photovoltaic module provided in an embodiment of the present invention.

Detailed ways

Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that the relative arrangement of components and steps, numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present invention unless otherwise specifically stated.

The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses.

Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered as part of the specification.

In all examples shown and discussed herein, any specific values should be interpreted as merely exemplary and not limiting. Therefore, other examples of the exemplary embodiments may have different values.

It should be noted that like reference numerals and letters refer to similar items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

The existing photovoltaic cell cutting technology generally cuts the whole cell into two half cells after the whole cell is produced, and then produces photovoltaic modules; an integrated cutting and welding machine is used to complete the cutting and welding process. When cutting, the whole cell is placed in the equipment, and the camera in the equipment will automatically capture the grid line position to determine the starting point of the cutting for cutting; cutting the front of the cell at the module end will cause the front structure to be destroyed, resulting in many microcracks, the tunneling oxidation structure on the back of the cell will fall off, and a large amount of dust will be adsorbed on the back of the cell; cutting the back of the cell at the module end will cause a large number of defects on the diffusion surface. When the recombination rate of the cell edge surface is high, the front surface recombination is serious. After cutting, the area within a certain range around the edge of the cell is affected.

Refer to Figure 1, which is a schematic diagram of the interface between the ideal and actual situations of cutting photovoltaic cells. When cutting photovoltaic cells, a smooth cut surface is ideally produced, which does not cause a decrease in efficiency; but in actual cutting, molten silicon will appear on the cut surface and the surrounding surface, and slicing will cause significant damage to the cut edge of the photovoltaic cell, increase recombination, and cause a significant decrease in efficiency.

Referring to FIG. 2 , FIG. 2 is a flow chart of a method for preparing a photovoltaic cell provided in an embodiment of the present invention; this embodiment provides a method for preparing a photovoltaic cell 100, comprising:

Step S1: providing a phosphorus-diffused silicon substrate 00, wherein the phosphorus-diffused silicon substrate 00 has a first surface 01;

Specifically, in combination with Figures 2 and 3, Figure 3 is a flow chart of the preparation of photovoltaic cells in the experimental group of the present invention. The silicon substrate 00 includes a first surface 01 and a second surface 02 that are relatively arranged. In this embodiment, the first surface 01 can be the front side (the surface facing the sun, that is, the light-receiving surface), and the second surface 02 can be the back side (the surface facing away from the sun, that is, the backlight surface); in this embodiment, phosphorus diffusion on the second surface 02 of the silicon substrate 00 can be performed using a tubular phosphorus diffusion device to use phosphorus trioxide to diffuse phosphorus on the back amorphous silicon surface of the silicon substrate 00 to form a doped polycrystalline silicon layer; the process temperature of the phosphorus diffusion can be 800°C, the square resistance after phosphorus diffusion can be 50ohm/squ, the thickness of the phosphorus silicon glass can be 40mm, the doping concentration of phosphorus in the polycrystalline silicon can be 3E20cm ^-3 , and the junction depth can be 150mm.

It should be noted that the silicon substrate 00 may be an N-type silicon substrate, and the silicon substrate 00 may be a crystalline silicon substrate, such as a polycrystalline silicon substrate, a single crystal silicon substrate, a microcrystalline silicon substrate or a silicon carbide substrate. The embodiment of the present application does not limit the specific type of the silicon substrate 00.

Step S2: cutting the first surface 01 of the silicon substrate 00 along a direction perpendicular to the thickness of the silicon substrate 00 to obtain the cut silicon substrate 00;

Specifically, the silicon substrate 00 is the core component of the photovoltaic cell, and its size is directly related to the power output of the photovoltaic cell and the size of the photovoltaic module. The size of the silicon substrate 00 is generally expressed by the side length or diagonal length. Common sizes of the whole silicon substrate 00 are 156mm×156mm, 156.75mm×156.75mm, 125mm×125mm, etc. In order to reduce manufacturing costs and installation flexibility, the whole silicon substrate 00 is often cut into half pieces for subsequent production. In this embodiment, the silicon substrate 00 after phosphorus expansion is cut, and only the production of the subsequent process needs to be cut. The size of the production equipment can be modified to match the size of the half-cell battery cell, and there is no need to modify the size of the production equipment of the entire production line, thereby simplifying the production equipment; the first surface 01 of the silicon substrate 00 is cut along a direction perpendicular to the thickness of the silicon substrate 00. It can be understood that the first surface 01 of the silicon substrate 00 can be the front side (light-receiving side) of the silicon substrate 00, and the second surface 02 of the silicon substrate 00 can be the back side (backlight side) of the silicon substrate 00. The direction perpendicular to the thickness of the silicon substrate 00 refers to the direction from the first surface 01 of the silicon substrate 00 to the second surface 02, that is, from the front side of the silicon substrate 00 to the back side. The direction of the surface; the cutting method of the silicon substrate 00 may include: laser cutting, abrasive cutting and diamond cutting; wherein, abrasive cutting is to cut the silicon wafer by a certain abrasive in a high-speed rotating manner, which has excellent lubricity, can speed up the cutting speed, and reduce the surface damage of the photovoltaic cell after cutting; diamond cutting is to cut the silicon wafer by a cutting blade made of diamond, which has the characteristics of high efficiency, low cost, high precision, narrow cutting seam, low surface damage, and low fragmentation rate, and the cutting surface is flat, the service life is long, and no lubricant is required during cutting, which is environmentally friendly; laser cutting mainly irradiates the silicon substrate 00 with a focused laser beam, and then moves the silicon substrate 00 or the laser head. Since the material of the silicon substrate 00 is removed due to gasification, the silicon substrate 00 can be cut and diced by laser along the moving direction. Cutting on the silicon substrate 00 by a high-energy laser beam can achieve high-quality and high-efficiency cutting. Since the laser spot is small, the energy density is high, and the cutting speed is fast, laser cutting can obtain better cutting quality; no harmful substances are generated during the laser cutting process, which is environmentally friendly; the speed of laser cutting is very fast, and a large amount of cutting work can be completed in a short time, thereby improving production efficiency.

Optionally, when the cutting method of the silicon substrate 00 is laser cutting, the direction of the laser operation is along the thickness direction perpendicular to the silicon substrate 00; it is understandable that after the silicon substrate 00 is cut, it is required to perform etching, passivation, coating, sintering and other processes to make a photovoltaic cell. The photovoltaic cell includes a silicon substrate 00, a first electrode 70 and a second electrode 80 located on the surface of the silicon substrate 00; the first electrode 70 and/or the second electrode 80 can be a main grid line, and a fine grid line intersecting with the main grid line, the main grid line is used to converge current and provide sufficient pulling force, and the fine grid line is used to collect the current generated by the photovoltaic cell 100, which can increase the light absorption rate and output current, thereby improving the conversion efficiency of the photovoltaic cell; the direction of the laser operation is along the thickness direction perpendicular to the silicon substrate 00, that is, when the cutting method of the silicon substrate 00 is laser cutting, the direction of the laser operation can be the extension direction of the fine grid line.

Optionally, when the cutting method of the silicon substrate 00 is laser cutting, the laser power range of the laser cutting is 15-20W; the laser frequency range of the laser cutting is 100-150kHz; and the laser running speed range of the laser cutting is 400-500mm/s.

Specifically, when the cutting method of the silicon substrate 00 is laser cutting, if the laser power of the laser cutting is less than 15W, the laser power is too small, which may easily lead to a small cutting degree, and the silicon substrate 00 is difficult to be separated after cutting; if the laser power of the laser cutting is greater than 20W, the laser power is too large, which may easily lead to serious silicon melting on the silicon substrate 00, and the incisions may fuse together, making the silicon substrate 00 difficult to be separated; therefore, the laser power range of the laser cutting is designed to be 15-20W, which can not only ensure that the cutting degree can separate the silicon substrate 00 after cutting, but also avoid silicon melting on the silicon substrate 00, and avoid the incisions from fusing together again and becoming unable to be separated; specifically, the laser power of the laser cutting can be 15W, 16W, 17W, 18W, 19W or 20W.

When the cutting method of the silicon substrate 00 is laser cutting, if the laser frequency of the laser cutting is less than 100kHz, the laser frequency is too small to make the silicon substrate 00 unable to be broken apart after cutting; if the laser frequency of the laser cutting is greater than 150kHz, the laser frequency is too large, which may easily cause excessive damage to the silicon substrate 00; therefore, the laser frequency range of the laser cutting is designed to be 100-150kHz, which can not only avoid excessive damage to the track 00 caused by excessive laser frequency, but also ensure that the silicon substrate 00 can be broken apart after cutting; specifically, the laser frequency of the laser cutting can be 100kHz, 110kHz, 120kHz, 130kHz, 140 or 150kHz.

When the cutting method of the silicon substrate 00 is laser cutting, if the laser running speed of the laser cutting is greater than 500mm/s, the laser runs too fast and the silicon substrate 00 cannot be broken apart after cutting; if the laser running speed of the laser cutting is less than 400mm/s, the laser runs too slow and it is easy to cause excessive damage to the silicon substrate 00; therefore, the laser running speed range of the laser cutting is designed to be 400-500mm/s, which can not only avoid excessive damage to the silicon substrate 00 caused by excessive laser frequency, but also ensure that the silicon substrate 00 can be broken apart after cutting; specifically, the laser running speed of the laser cutting can be 400mm/s, 420mm/s, 440mm/s, 460mm/s, 480mm/s or 500mm/s.

Step S3: etching the first surface 01 of the cut silicon substrate 00 to obtain the etched silicon substrate 00; wherein the outer surface of the etched silicon substrate 00 is the selective emitter 10;

Specifically, the first surface 01 of the cut silicon substrate 00 is etched. This process can preliminarily repair the cutting damage on the edge and surface of the silicon substrate 00, and can also remove the phosphorus silicon glass layer on the surface of the silicon substrate 00; specifically, a mixed solution of hydrofluoric acid (HF)/nitric acid (HNO3) can be used for acid etching and polishing, and a potassium hydroxide (KOH) solution can be used for alkaline etching and polishing. The first surface 01 of the etched silicon substrate 00 can be a selective emitter 10;

The selective emitter 10 on the outer surface of the first surface 01 of the silicon substrate 00 refers to heavy doping at the contact portion between the metal gate line (electrode) and the silicon substrate 00, and light doping at the position between the electrodes. Such a structure can reduce the recombination of the diffusion layer, thereby improving the short-wave response of the light, and at the same time reducing the contact resistance between the front metal electrode and silicon, so that the short-circuit current, open-circuit voltage and fill factor are all improved, thereby improving the conversion efficiency.

It should be noted that when the silicon substrate 00 is an N-type silicon substrate, the emitter can be a P-type emitter, and the P-type emitter can be a boron-doped diffusion layer or a gallium-doped diffusion layer; both the boron-doped diffusion layer and the gallium-doped diffusion layer are emitters formed by diffusing the doping source atoms to a certain depth on the front surface through a diffusion process using a corresponding doping source; illustratively, when preparing a boron-doped diffusion layer, the doping source can be liquid boron tribromide or boron trichloride; boron atoms are diffused through a boron source to form a selective emitter 10; since the surface of the silicon substrate 00 has a high concentration of boron, a borosilicate glass layer (BSG) is usually formed, and this borosilicate glass layer has a metal gettering effect, which will affect the normal operation of the solar cell and needs to be removed later.

Optionally, referring to FIG. 4 , FIG. 4 is a schematic diagram of the structure of etching a silicon substrate by a chain cleaning machine in the present invention, wherein the first surface 01 of the cut silicon substrate 00 is etched, including:

The first surface 01 of the cut silicon substrate 00 is etched by using a chain cleaning machine 1; wherein the chain cleaning machine 1 includes a conveyor belt 2, and the cut silicon substrate 00 is placed on the conveyor belt 2 for etching; the first surface 01 of the silicon substrate 00 faces one side of the conveyor belt 2, and the cut surface 03 of the silicon substrate 00 faces the moving direction X of the conveyor belt.

Specifically, referring to FIG. 4 , a chain-type trough integrated device is used to etch the cut silicon substrate 00. First, the chain-type cleaning machine 1 is used to etch the first surface 01 of the silicon substrate 00. The silicon substrate 00 needs to be placed on the conveyor belt 2 of the chain-type cleaning machine 1, and the silicon substrate 00 is partially immersed in the liquid surface 3 of the etching solution, so that the first surface 01 of the silicon substrate 00 is in contact with the upper surface of the conveyor belt 2. When the silicon substrate 00 has a cutting surface 03, the cutting surface 03 of the silicon substrate 00 is simultaneously directed toward the moving direction X of the conveyor belt, that is, the water flow direction Y of the etching solution is opposite to the moving direction X of the conveyor belt. During the movement of the conveyor belt 2, the cutting surface 03 of the silicon substrate 00 will move against the water flow of the etching solution, and the cutting surface 03 of the silicon substrate 00 will contact the etching solution before the rest of the silicon substrate 00, so that the surface material of the cutting surface 03 is fully cleaned.

Among them, the chain cleaning machine 1 generally contains a hydrogen fluoride (HF) solution, the volume concentration range of the hydrogen fluoride solution can be 20%-40%, and the belt speed of the conveyor belt 2 can be 4m/min; if the volume concentration of the hydrogen fluoride solution is less than 20%, the phosphosilicate glass layer on the first side 01 of the silicon substrate 00 cannot be removed; if the volume concentration of the hydrogen fluoride solution is greater than 40%, the cost is wasted; therefore, setting the volume concentration range of the hydrogen fluoride solution to 20%-40% can not only avoid the problem of being unable to remove the phosphosilicate glass layer on the first side 01 of the silicon substrate 00, but also avoid the problem of wasting costs; specifically, the volume concentration of the hydrogen fluoride solution can be 20%, 25%, 30%, 35% or 40%.

After cleaning in the chain cleaning machine 1, the silicon substrate 00 is cleaned in a tank cleaning machine. The chemical solution in the tank cleaning machine includes hydrofluoric acid (HF), hydrochloric acid (HCl), sodium hydroxide (NaOH), and _hydrogen peroxide ( _H2O2 ). In the tank cleaning machine, the silicon substrate 00 is vertically immersed in the chemical solution. The chemical solution can reduce the damage to the first surface 01 and the cut surface 03 of the silicon substrate 00. The damage to the cut surface 03 will be cleaned and repaired by more than 50%.

Step S4 : the cut silicon substrate 00 has a cut surface 03 , and the side of the selective emitter 10 away from the first surface 01 and the cut surface 03 are passivated to obtain the silicon substrate 00 having a passivation layer 40 .

Specifically, the side of the selective emitter 10 away from the first surface 01 and the cut surface 03 are passivated to obtain a silicon substrate 00 having a passivation layer 40. It can be understood that the number of layers of the passivation layer 40 can be one or two layers, and the passivation layer 40 includes a front sub-passivation layer 401 and a side sub-passivation layer 402. In this embodiment, the side of the selective emitter 10 away from the first surface 01 can be passivated to form a front sub-passivation layer 401 on the front of the silicon substrate 00; at the same time, the cut surface 03 of the silicon substrate 00 is passivated to form a side sub-passivation layer 402 on the cut surface 03 of the silicon substrate 00; this embodiment can also be preferably First, the side of the selective emitter 10 away from the first surface 01 is passivated to form a front sub-passivation layer 401 on the front side of the silicon substrate 00; after obtaining the front sub-passivation layer 401, the cut surface 03 of the silicon substrate 00 is passivated to form a side sub-passivation layer 402 on the cut surface 03 of the silicon substrate 00; the passivation order of the first surface 01 and the cut surface 03 of the silicon substrate 00 can be adjusted according to actual conditions, and this embodiment does not specifically limit the passivation order of the first surface 01 and the cut surface 03 of the silicon substrate 00; along the thickness direction of the silicon substrate 00, the length of the side sub-passivation layer 402 can be greater than 1.5μm.

The first surface 01 and the cut surface 03 of the silicon substrate 00 are passivated, and the cut surface 01 and the area of the first surface 01 affected by the cut surface 03 can be further repaired on the basis of the etching process; specifically, a front sub-passivation layer 401 can be deposited on the first surface 01 of the silicon substrate 00 by a thermal atomic deposition (ALD) method, and a side sub-passivation layer 402 can be deposited on the cut surface 03 at the same time; the process parameters may include: the temperature may be 260° C., and the deposition thickness may be 4 nm; the materials of the front sub-passivation layer 401 and the side sub-passivation layer 402 may include but are not limited to at least one of silicon oxide, silicon nitride, silicon oxynitride, aluminum oxide, etc., or any combination thereof; the front sub-passivation layer 401 and the side sub-passivation layer 402 can be used to fix negative charges and eliminate parasitic capacitance effects, and can produce a good passivation effect on the silicon substrate 00, which is helpful to improve the conversion efficiency of photovoltaic cells;

The thickness of the front sub-passivation layer 401 can range from 10nm to 120nm. If the thickness of the front sub-passivation layer 401 is less than 10nm, the front sub-passivation layer 401 is too low and cannot repair the damage to the silicon substrate 00 after cutting; if the thickness of the front sub-passivation layer 401 is greater than 120nm, the front sub-passivation layer 401 is too high, which will make the contact between the slurry and the photovoltaic cell in the subsequent screen printing process worse and increase the cost; therefore, the thickness of the front sub-passivation layer 401 can range from 10nm to 120nm, which can not only repair the damage to the silicon substrate 00 after cutting, but also ensure the contact between the slurry and the photovoltaic cell in the subsequent screen printing process, while avoiding increasing the cost; the thickness of the front sub-passivation layer 401 can specifically be 10nm, 20nm, 30nm, 42nm, 50nm, 60nm, 70nm, 80nm, 90nm, 100nm or 120nm, etc., of course, it can also be other values within the above range, which are not limited here.

It should be noted that, in the photovoltaic cell preparation method provided in the present embodiment, a silicon substrate 00 after phosphorus diffusion is provided, and the first surface 01 of the silicon substrate 00 is cut along a direction perpendicular to the thickness of the silicon substrate 00 to obtain the cut silicon substrate 00; the first surface 01 of the cut silicon substrate 00 is etched to obtain the etched silicon substrate 00; the side of the selective emitter 10 away from the first surface 01 and the cut surface 03 are passivated to obtain the silicon substrate 00 having a passivation layer 40; the steps of the present embodiment are interrelated and cannot be divided, and the order of the above steps cannot be adjusted. If the order of the above steps is adjusted, the technical effect achieved by the present embodiment cannot be achieved.

The photovoltaic cell 100 can be a TOPCon (Tunnel Oxide Passivated Contact) cell. The TOPCon cell has high conversion efficiency, excellent interface passivation and carrier transport capability, and high Voc (open circuit voltage); low photoinduced attenuation, and extremely low boron content in phosphorus-doped N-type crystalline silicon, which weakens the influence of boron and oxygen; high compatibility of process equipment production lines, and can be compatible with high-temperature preparation process production lines of PERC (passivated emitter back contact) and N-PERT (N-Passivated Emitter, Rear Totally-diffused) bifacial cells; N-type TOPCon cells can be combined with SE (seletive-emitter, selective emitter), IBC (Interdigitated Back Contact), multi-main grid, half-cell, and stacking technology to significantly improve cell efficiency and component power.

In order to reflect the effect of the photovoltaic cell preparation method provided in this embodiment, a comparison of the effects of the photovoltaic cell 100 of the experimental group and the photovoltaic cell 100 of the control group was also performed;

A comparison between the photovoltaic cell 100 of an experimental group and the photovoltaic cell 100 of a control group is as follows:

The experimental design is as follows: from texturing to phosphorus diffusion, the production line has fixed processes (that is, the preparation methods are texturing, boron diffusion, back etching, tunneling oxidation, and phosphorus diffusion in sequence), and after phosphorus diffusion, the test is performed and silicon substrates with similar minority carrier lifetimes are selected and divided into a control group and an experimental group.

test group

Referring to FIG. 3 , FIG. 3 is a flow chart of the preparation of photovoltaic cells of the experimental group of the present invention. The steps of preparing the test piece of the experimental group are as follows:

Step 1, slicing: Use a laser scriber to cut from the first surface 01 (i.e., the front surface or the boron diffusion surface) of the silicon substrate 00 along the direction of the selective emitter formed by boron diffusion (i.e., the extension direction of the fine gate line), and then break it into two halves;

Step 2, front etching: Use PSG removal + alkali polishing automated equipment for cleaning. The equipment is a chain-type trough integrated equipment. In order to achieve the best damage repair effect, when the silicon substrate 00 is placed in the chain machine, the cutting surface 03 of the silicon substrate 00 is placed toward the moving direction of the silicon substrate 00, and then it is cleaned by a trough cleaning machine. The chemicals in the trough cleaning machine include hydrofluoric acid (HF), hydrochloric acid (HCl), sodium hydroxide (NaOH), and hydrogen peroxide (H2O2); the above chemicals can reduce the damage to the surface and cut surface of the silicon substrate 00;

Step 3, front passivation: a passivation layer 40 (i.e., an aluminum oxide thin film structure) is formed on the first surface 01 and the cut surface 03 of the silicon substrate 00 through a passivation process. The passivation layer 40 has excellent gap-filling ability and can further repair the damage to the first surface 01 and the cut surface 03 caused by the laser.

Step 4, double-sided coating: Finally, the silicon substrate 00 is coated. The coating on the first side 01 (i.e., the silicon nitride thin film structure) can better repair the cross-section cutting damage. After coating, it enters the screen printing and sintering process. The test piece of the experimental group can be taken out. During the process, you need to use tweezers carefully to pick it up.

Step 5, preparing photovoltaic modules: arranging multiple photovoltaic cells 100 in sequence, connecting multiple photovoltaic cells 100 in series through welding strips to form a cell string, and multiple parallel cell strings are arranged in the same direction; stacking the front panel, the first packaging film, the photovoltaic cell, the second packaging film and the back panel in sequence; applying pressure along the stacking direction, melting the first packaging film and the second packaging film under vacuum and high temperature conditions, and bonding the cell string, the front panel and the back panel together, cooling and solidifying to obtain a photovoltaic module; the edge damage of the half-cell photovoltaic cell 100 of the experimental group is repaired, and it is wrapped with a passivation layer and an anti-reflection layer (SiNx), so that the surface recombination of the edge of the half-cell photovoltaic cell 100 is greatly reduced, and the efficiency of the manufactured photovoltaic module is almost the same as that of the whole photovoltaic cell.

Control group

Referring to FIG. 5 , FIG. 5 is a flow chart of preparing photovoltaic cells of the control group of the present invention. The steps of preparing the test pieces of the control group are as follows:

After the minority carrier lifetime test, the production line fixed process from phosphorus diffusion to sintering annealing (i.e., the preparation method is front etching, front passivation, double-sided coating, screen printing and sintering in sequence), and then half of the slice is cut by a laser scribing machine to obtain the control group photovoltaic cell 100;

Afterwards, multiple photovoltaic cells 100 are arranged in sequence, and multiple photovoltaic cells 100 are connected in series in sequence through welding strips to form a cell string, and multiple parallel cell strings are arranged in the same direction; the front plate, the first packaging film, the photovoltaic cell, the second packaging film and the back plate are stacked together in sequence; pressure is applied along the stacking direction, the first packaging film and the second packaging film are melted under vacuum and high temperature conditions, and the cell string, the front plate and the back plate are adhered together, and cooled and solidified to obtain a photovoltaic module; the photovoltaic cells 100 of the control group are directly made into photovoltaic modules after cutting, and the edges of half-sheet photovoltaic cells 100 are exposed, so that the surface compounding of the edges of the half-sheet photovoltaic cells 100 is relatively large, and the efficiency can be reduced by about 1% relative to the whole photovoltaic cell.

test analysis

The half-cells of the experimental group and the control group were placed closely in a photoluminescence imaging device (PL) for shooting and testing, as shown in Figures 6 and 7. Figure 6 is the PL imaging result of the photovoltaic cell of the experimental group in the present invention, and Figure 7 is the PL imaging result of the photovoltaic cell of the control group in the present invention. It should be noted that the grayscale bars on the right side of Figures 6 and 7 represent the grayscale value range of the entire image, and the darker the color, the shorter the minority carrier lifetime; the blackened area in the imaging result corresponds to the area with low minority carrier lifetime, and the black long strip area in the middle of the image is the low minority carrier lifetime area caused by the cutting damage of the photovoltaic cell. It can be seen from the figure that the width of the black long strip in the PL image of the experimental group is smaller than that of the control group. This is because the process after phosphorus expansion of the photovoltaic cell in the experimental group will repair part of the cutting damage. The circled position in the control group is the influence of the laser on the area around the cutting. This kind of superficial damage was not found in the experimental group because the cleaning and other processes after phosphorus expansion can eliminate the superficial surface damage.

The experimental group and the control group were tested using a minority carrier lifetime tester. Compared with the whole wafer, the minority carrier lifetime of the experimental group decreased by 3%, and that of the control group decreased by 20%.

It can be seen from the above embodiments that the method for preparing a photovoltaic cell provided in this embodiment achieves at least the following beneficial effects:

The present embodiment provides a method for preparing a photovoltaic cell, comprising: providing a silicon substrate 00 after phosphorus diffusion, cutting the first surface 01 of the silicon substrate 00 along a direction perpendicular to the thickness of the silicon substrate 00 to obtain the cut silicon substrate 00; etching the first surface 01 of the cut silicon substrate 00 to obtain the etched silicon substrate 00; the outer surface of the etched silicon substrate 00 is a selective emitter 10; passivating the side of the selective emitter 10 away from the first surface 01 and the cut surface 03 to obtain a silicon substrate 00 with a passivation layer 40; cutting the photovoltaic cell 100 into half slices after the phosphorus diffusion process in the preparation of the photovoltaic cell, and then etching and passivating. The etching and passivation process can reduce the edge cutting damage of the photovoltaic cell 100, reduce the surface recombination of the cut surface, and increase the efficiency. Compared with the slicing before texturing, the impact on production capacity is smaller.

In some optional embodiments, referring to FIG. 8 , FIG. 8 is a flow chart of an optional implementation method of obtaining a phosphorus-diffused silicon substrate provided by an embodiment of the present invention; Step S1: providing a phosphorus-diffused silicon substrate 00, which also includes:

Step S101: obtaining a silicon substrate 00;

Specifically, in this embodiment, the silicon substrate 00 can first be pre-cleaned with a mixed aqueous solution of KOH and hydrogen peroxide to remove metal and organic pollutants on the surface, and then the silicon substrate 00 can be textured to form a velvet structure 90 (for example, a pyramid structure). The texture treatment method can be chemical etching, laser etching, mechanical method, plasma etching, etc., which are not limited here; illustratively, the surface of the silicon substrate 00 can be textured using a NaOH solution. Since the corrosion of the NaOH solution is anisotropic, a pyramid velvet structure 90 can be prepared; it can be understood that the surface of the silicon substrate 00 has a velvet structure 90 through the texture treatment, which produces a light trapping effect, increases the amount of light absorbed by the photovoltaic cell 100, and thus improves the conversion efficiency of the photovoltaic cell 100.

Step S102: performing boron diffusion on the first surface 01 of the silicon substrate 00 to obtain the silicon substrate 00 having the selective emitter 10;

Specifically, a tubular boron diffusion device is used to perform boron diffusion on the front pyramid to form a selective emitter 10. The process temperature of the boron diffusion can be 1000°C. The square resistance after the boron diffusion is 100ohm/squ. The doping concentration of boron in the silicon substrate 00 is 2E19cm ^-3 , and the junction depth is 0.8 micrometers.

Step S103: the silicon substrate 00 after boron diffusion has a second surface 02 arranged opposite to the first surface 01, and a tunneling oxide layer 20 is formed on the second surface 02 of the silicon substrate 00;

Specifically, a tunneling oxide layer 20 is formed on the second surface 02 of the silicon substrate 00 by high temperature oxidation. The tunneling oxide layer 20 may be a silicon dioxide (SiO ₂ ) layer. The process parameters include: an oxygen (O ₂ ) flow rate range of 30000sccm-38000sccm, a temperature range of 580°C-620°C, and a thickness range of 1nm-2nm for the tunneling oxide layer 20.

Step S104: depositing an amorphous silicon layer on a side of the tunnel oxide layer 20 away from the silicon substrate 00;

Specifically, the amorphous silicon layer is deposited on the side of the tunnel oxide layer 20 away from the silicon substrate 00 by thermal decomposition. The process parameters include: the flow range of silicon tetrahydride (SiH ₄ , also known as silane) is 1300sccm-1700sccm, the temperature range is 590°C-610°C, and the thickness of the amorphous silicon layer can range from 30nm to 150nm.

Step S105 : performing phosphorus diffusion on a side of the amorphous silicon layer away from the tunneling oxide layer 20 to form a doped conductive layer 30 .

Specifically, a tubular phosphorus diffusion device is used to use phosphorus trioxide to diffuse phosphorus on a side of the amorphous silicon layer away from the tunneling oxide layer 20 to form the doped conductive layer 30. The process parameters include: a nitrogen (N ₂ ) flow rate range of 500sccm-2000sccm, an oxygen (O ₂ ) flow rate range of 600sccm-3000sccm, a temperature range of 800°C-920°C, a square resistance after phosphorus diffusion of 50ohm/squ, a phosphorus doping concentration in the amorphous silicon layer of 3E20cm ^-3 , and a junction depth of 150mm.

In some optional embodiments, referring to FIG. 9 , FIG. 9 is a flow chart of generating a first anti-reflection layer and a second anti-reflection layer, a first electrode and a second electrode on a surface of a silicon substrate having a passivation layer provided by an embodiment of the present invention, step S4: passivating a side of the selective emitter 10 away from the first surface 01 to obtain a silicon substrate 00 having a passivation layer 40, and then further comprising:

Step S401: the passivated silicon substrate 00 has a second surface 02 corresponding to the first surface 01; the first surface 01 and the second surface 02 of the silicon substrate 00 having the passivation layer 40 are plated to obtain the silicon substrate 00 having the first anti-reflection layer 50 and the second anti-reflection layer 60;

Specifically, a first anti-reflection layer 50 is formed on the first front surface 01, and a second anti-reflection layer 60 is formed on the second surface 02 by plasma chemical vapor deposition (PECVD). The process parameters include: ammonia (NH ₃ ) and silicon tetrahydride (SiH ₄ , also known as: silane) in a volume ratio of 4:1-10:1, a temperature range of 480°C-550°C, and a pressure of 210Pa; the first anti-reflection layer 50 and the second anti-reflection layer 60 can reduce the reflection of incident light; the first anti-reflection layer 50 and the second anti-reflection layer 60 can be a silicon oxide layer, an aluminum oxide layer, a silicon nitride layer or a silicon nitride layer; wherein the first anti-reflection layer 50 includes a front sub-anti-reflection layer 501 and a side sub-anti-reflection layer 502; the front sub-anti-reflection layer 501 is located on the side of the front sub-passivation layer 401 away from the silicon substrate 00, and the side sub-anti-reflection layer 502 is located on the side of the side sub-passivation layer 402 away from the silicon substrate 00; coating the first surface 01 and the cut surface 03 of the silicon substrate 00 can further repair the cut surface 01 and the area of the first surface 01 affected by the cut surface 03 on the basis of the etching process and the passivation process.

Step S402 : forming a first electrode 70 on the first anti-reflection layer 50 on the first surface 01 , and forming a second electrode 80 on the second anti-reflection layer 60 on the second surface 02 .

Specifically, a screen printer is used to print metal paste on the first surface 01 and the second surface 02 respectively to obtain grid lines, wherein the grid lines include main grid lines and fine grid lines, the main grid lines are used to gather current and provide sufficient pulling force, and the fine grid lines are used to collect current generated by the photovoltaic cell 100, and the printing order of the first surface 01 and the second surface 02 is to print the fine grid lines first and then print the main grid lines; the silicon substrate 00 is sent to a sintering furnace for sintering at a temperature range of 750-880°C, so that the grid lines penetrate multiple film layers, and a first electrode 70 is formed on the first anti-reflection layer 50 of the first surface 01, and a second electrode 80 is formed on the second anti-reflection layer 60 of the second surface 02.

Referring to FIG. 10 , FIG. 10 is a schematic diagram of the structure of a photovoltaic cell provided in an embodiment of the present invention. Based on the same inventive concept, this embodiment further provides a photovoltaic cell 100, including a photovoltaic cell 100 prepared by the method for preparing the photovoltaic cell 100 in any of the above embodiments; the photovoltaic cell 100 includes a silicon substrate 00, the silicon substrate 00 has a cutting surface 03, and the cutting surface 03 is sequentially stacked with a passivation layer 40 and a first anti-reflection layer 50 along a direction away from the silicon substrate 00.

Specifically, the photovoltaic cell 100 includes a silicon substrate 00; the silicon substrate 00 includes a first surface 01 and a second surface 02 that are arranged opposite to each other, and along the thickness direction of the silicon substrate 00, the first surface 01 of the silicon substrate 00 is provided with a front sub-anti-reflection layer 501, a front sub-passivation layer 401, and a selective emitter 10 in sequence; along the thickness direction of the silicon substrate 00, the second surface 02 of the silicon substrate 00 is provided with a tunneling oxide layer 20, a doped conductive layer 30, and a second anti-reflection layer 60 in sequence;

The silicon substrate 00 also includes a cutting surface 03; along a direction perpendicular to the thickness of the silicon substrate 00, the cutting surface 03 of the silicon substrate 00 is sequentially provided with a side sub-passivation layer 402 and a side sub-anti-reflection layer 502; the front sub-passivation layer 401 can be connected with the side sub-passivation layer 402 to form a passivation layer 40, and the front sub-anti-reflection layer 501 can be connected with the side sub-anti-reflection layer 502 to form a first anti-reflection layer 50.

The photovoltaic cell 100 in this embodiment includes a silicon substrate 00, and the silicon substrate 00 has a cutting surface 03. The cutting surface 03 is sequentially stacked with a passivation layer 40 and a first anti-reflection layer 50 in a direction away from the silicon substrate 00. After the phosphorus diffusion process in the preparation of the photovoltaic cell 100, the photovoltaic cell 100 is cut into halves, and then etched, passivated and coated, so that the cutting surface 03 has a passivation layer 40 and a first anti-reflection layer 50. The etching and passivation process can reduce the edge cutting damage of the photovoltaic cell 100, reduce the surface recombination of the cutting surface, and increase the efficiency. Compared with the slicing before texturing, the impact on production capacity is smaller.

In some optional embodiments, refer to Figure 11, which is a local enlarged view of point A in Figure 10; the length of the passivation layer 40 on the cutting surface 03 along the thickness direction of the silicon substrate 00 is less than the thickness of the photovoltaic cell 100 along the thickness direction of the silicon substrate 00; the length of the first anti-reflection layer 50 on the cutting surface 03 along the thickness direction of the silicon substrate 00 is less than the thickness of the photovoltaic cell 100 along the thickness direction of the silicon substrate 00.

Specifically, the length of the passivation layer 40 on the cutting surface 03 along the thickness direction of the silicon substrate 00 is less than the thickness of the photovoltaic cell 100 along the thickness direction of the silicon substrate 00. It can be understood that the side sub-passivation layer 402 is deposited on the cutting surface 03 of the silicon substrate 00, and the length of the side sub-passivation layer 402 along the thickness direction of the silicon substrate 00 is less than the thickness of the photovoltaic cell 100 along the thickness direction of the silicon substrate 00; that is, on the cutting surface 03 of the silicon substrate 00, the side sub-passivation layer 402 does not contact the film layer structure of the second surface 02 of the silicon substrate 00, thereby avoiding the risk of causing a short circuit;

The length of the first anti-reflection layer 50 on the cutting surface 03 along the thickness direction of the silicon substrate 00 is less than the thickness of the photovoltaic cell 100 along the thickness direction of the silicon substrate 00. It can be understood that a side sub-anti-reflection layer 502 is formed by coating on the cutting surface 03 of the silicon substrate 00, and the length of the side sub-anti-reflection layer 502 along the thickness direction of the silicon substrate 00 is less than the thickness of the photovoltaic cell 100 along the thickness direction of the silicon substrate 00; that is, on the cutting surface 03 of the silicon substrate 00, the side sub-anti-reflection layer 502 does not contact the film layer structure of the second surface 02 of the silicon substrate 00, thereby avoiding the risk of causing a short circuit.

Referring to FIG. 12 , FIG. 12 is a schematic diagram of the structure of a photovoltaic module provided in an embodiment of the present invention. Based on the same inventive concept, this embodiment further provides a photovoltaic module 000, including a laminate 200 and a frame 300 wrapped around the laminate 200. The laminate 200 includes a front panel 400, a first packaging film 500, a photovoltaic cell 100, a second packaging film 600 and a back panel 700 arranged in sequence. The photovoltaic cell 100 includes the photovoltaic cell 100 in the above-mentioned embodiment.

Specifically, the present embodiment further provides a photovoltaic assembly 000, including a laminate 200 and a frame 300 wrapped around the laminate 200, the frame 300 is used to carry and accommodate the laminate 200, the material of the frame 300 can be a composite material, the frame 300 can be a cavity frame or an S-shaped frame, and the structure of the frame 300 can be set according to actual conditions, and this embodiment does not specifically limit this;

The laminate 200 includes a front plate 400, a first packaging film 500, a photovoltaic cell 100, a second packaging film 600 and a back plate 700 which are arranged in sequence, and the photovoltaic cell 100 includes the photovoltaic cell 100 in the above embodiment;

The front panel 400 can be made of glass with high light transmittance, which can reach more than 92%. Low-iron tempered embossed glass is generally used, and the thickness range can be 2.7-3.2 mm. The thickness of the front panel 400 can be 2.7 mm, 3 mm, 3.1 mm or 3.2 mm. The thickness of the front panel 400 can be set according to actual conditions, and this embodiment does not specifically limit this. Within the wavelength range of 380 to 1100 nm of the spectral response of the solar cell, the light transmittance can reach more than 91%, and it has a higher reflectivity for infrared light greater than 1200 nm. The front panel 400 can be conventional flat glass, and the shape of the front panel 400 is no longer limited in this embodiment, and can be square, round or other shapes, as long as it can achieve the purpose of this embodiment. Of course, the front panel 400 can also be special-shaped glass, such as curved glass. This embodiment no longer limits the corresponding angle of the curved glass, and can be set according to actual conditions, which can be 5 degrees, 10 degrees, 15 degrees, 20 degrees, or other degrees.

The first packaging film 500 and/or the second packaging film 600 may be an ethylene-vinyl acetate copolymer packaging film, a polyethylene-octene co-elastomer packaging film, a polyvinyl butyral packaging film, an EP packaging film or an EPE packaging film; the first packaging film 500 and/or the second packaging film 600 are used to encapsulate and protect the photovoltaic cell 100, prevent the external environment from affecting the performance of the photovoltaic cell 100, and bond the front plate 400, the photovoltaic cell 100, and the back plate 700 together, and have a certain bonding strength, high light transmittance, reasonable cross-linking degree, excellent UV aging resistance and excellent moisture and heat aging resistance, extremely low shrinkage, long-term strong bonding performance to various back plates and glass, and high volume resistivity; the thickness of the first packaging film 500 and/or the second packaging film 600 may range from 0.3 to 0.5 mm;

The back panel 700 can be made of glass, TPT (polyvinyl fluoride composite film) or TPE (thermoplastic elastomer). The back panel 700 is used to protect the internal packaging materials and batteries from mechanical damage and external environmental corrosion. It also has good insulation properties, which largely determines the working life of the components. It has excellent weather resistance, low water vapor permeability, good electrical insulation, and certain bonding strength. The thickness of the back panel 700 can range from 0.2-3.2mm, and the thickness of the back panel 700 can be 0.2mm, 1mm, 2mm, 3mm or 3.2mm.

The present embodiment also provides a photovoltaic module 000 including the photovoltaic cell 100 in the above embodiment. After the phosphorus diffusion process in the preparation of the photovoltaic cell 100, the photovoltaic cell 100 is cut into halves, and then etched and passivated. The etching and passivation process can reduce the edge cutting damage of the photovoltaic cell 100, reduce the surface recombination of the cut surface, and increase the efficiency. Compared with slicing before texturing, the impact on production capacity is smaller.

It can be seen from the above embodiments that the photovoltaic cell preparation method, photovoltaic cell and photovoltaic module provided by the present invention achieve at least the following beneficial effects:

The invention provides a preparation method of a photovoltaic cell, a photovoltaic cell and a photovoltaic module. The preparation method comprises: providing a silicon substrate after phosphorus diffusion, cutting a first surface of the silicon substrate along a direction perpendicular to the thickness of the silicon substrate to obtain a cut silicon substrate; etching the first surface of the cut silicon substrate to obtain an etched silicon substrate; the outer surface of the etched silicon substrate is a selective emitter; passivating a side of the selective emitter away from the first surface and a cut surface to obtain a silicon substrate with a passivation layer; cutting the photovoltaic cell into half slices after the phosphorus diffusion process in the preparation of the photovoltaic cell, and then etching and passivating. The etching and passivation process can reduce the edge cutting damage of the photovoltaic cell, reduce the surface recombination of the cut surface, and increase the efficiency, and the influence on the production capacity is smaller than that of slicing before texturing.

Although some specific embodiments of the present invention have been described in detail by way of example, it will be appreciated by those skilled in the art that the above examples are for illustration only and are not intended to limit the scope of the present invention. It will be appreciated by those skilled in the art that the above embodiments may be modified without departing from the scope and spirit of the present invention. The scope of the present invention is defined by the appended claims.

Claims (10)

1. A method for preparing a photovoltaic cell, comprising: Providing a phosphorus-diffused silicon substrate, wherein the phosphorus-diffused silicon substrate has a first surface; Cutting the first surface of the silicon substrate along a direction perpendicular to the thickness of the silicon substrate to obtain the cut silicon substrate; Etching the first surface of the cut silicon substrate to obtain the etched silicon substrate; wherein the outer surface of the etched silicon substrate is a selective emitter; The silicon substrate after cutting has a cutting surface, and the side of the selective emitter away from the first surface and the cutting surface are passivated to obtain the silicon substrate with a passivation layer. 2 . The method for preparing a photovoltaic cell according to claim 1 , wherein the cutting method of the silicon substrate comprises: laser cutting, abrasive cutting and diamond cutting. 3 . The method for preparing a photovoltaic cell according to claim 2 , wherein when the silicon substrate is cut by laser cutting, the laser runs in a direction perpendicular to the thickness direction of the silicon substrate. 4. The method for preparing a photovoltaic cell according to claim 2 is characterized in that, when the cutting method of the silicon substrate is laser cutting, the laser power range of the laser cutting is 15-20W; the laser frequency range of the laser cutting is 100-150kHz; the laser running speed range of the laser cutting is 400-500mm/s. 5. The method for preparing a photovoltaic cell according to claim 1, wherein etching the first surface of the cut silicon substrate comprises: The first surface of the cut silicon substrate is etched using a chain cleaning machine; wherein the chain cleaning machine includes a conveyor belt, and the cut silicon substrate is placed on the conveyor belt for etching; the first surface of the silicon substrate faces one side of the conveyor belt, and the cut surface of the silicon substrate faces the moving direction of the conveyor belt. 6. The method for preparing a photovoltaic cell according to claim 1, characterized in that the step of providing a phosphorus-diffused silicon substrate further comprises: obtaining the silicon substrate; Performing boron diffusion on the first surface of the silicon substrate to obtain the silicon substrate having a selective emitter; The silicon substrate after boron diffusion has a second surface arranged opposite to the first surface, and a tunneling oxide layer is formed on the second surface of the silicon substrate; Depositing an amorphous silicon layer on a side of the tunnel oxide layer away from the silicon substrate; Phosphorus is diffused on a side of the amorphous silicon layer away from the tunnel oxide layer to form a doped conductive layer. 7. The method for preparing a photovoltaic cell according to claim 1, characterized in that the side of the selective emitter away from the first surface is passivated to obtain the silicon substrate having a passivation layer, and then further comprising: The passivated silicon substrate has a second surface corresponding to the first surface; the first surface and the second surface of the silicon substrate having the passivation layer are coated to obtain the silicon substrate having the first anti-reflection layer and the second anti-reflection layer; A first electrode is formed on the anti-reflection layer on the first surface, and a second electrode is formed on the anti-reflection layer on the second surface. 8. A photovoltaic cell, characterized in that it comprises a photovoltaic cell prepared by the method for preparing a photovoltaic cell according to any one of claims 1 to 7; the photovoltaic cell comprises the silicon substrate, the silicon substrate has a cutting surface, and the cutting surface is sequentially stacked with a passivation layer and a first anti-reflection layer in a direction away from the silicon substrate. 9. The photovoltaic cell according to claim 8 is characterized in that the length of the passivation layer on the cutting surface along the thickness direction of the silicon substrate is smaller than the thickness of the photovoltaic cell along the thickness direction of the silicon substrate; the length of the first anti-reflection layer on the cutting surface along the thickness direction of the silicon substrate is smaller than the thickness of the photovoltaic cell along the thickness direction of the silicon substrate. 10. A photovoltaic module, characterized in that it comprises a laminate and a frame wrapped around the laminate, the laminate comprises a front plate, a first packaging film, a photovoltaic cell, a second packaging film and a back plate arranged in sequence, and the photovoltaic cell comprises the photovoltaic cell according to claim 8 or 9.