A solar cell with a passivation layer at a cut edge and a method for preparing the same

Abstract

The present invention provides a solar cell with a passivation layer at the cutting edge and a preparation method thereof. The solar cell is a cell after being cut and sliced; wherein a first passivation layer and a second passivation layer are sequentially deposited on the cutting edge of the cell; wherein the first passivation layer is a silicon oxide layer and / or an aluminum oxide layer; and the second passivation layer is a silicon nitride layer. The preparation method comprises the following steps: firstly depositing a first passivation layer on the cutting edge of the cell after being cut and sliced, then depositing a second passivation layer on the first passivation layer, and finally performing light injection passivation to obtain a solar cell with a passivation layer at the cutting edge. The scheme of the present invention realizes the passivation of defects and impurities at the cutting edge, thereby improving the efficiency of the cell.

Description

Technical Field

[0001] The present invention relates to the technical field of solar cells, and in particular to a solar cell with a cut edge including a passivation layer and a preparation method thereof. Background Art

[0002] Over the past decade, the size of photovoltaic silicon wafers has been increasing, from 125mm to 156mm, 166mm, 182mm, and even 210mm. The power of photovoltaic modules has also increased rapidly with the increase in silicon wafer size, and the cost has been continuously reduced. However, as the size of silicon wafers increases, the current of single-chip cells continues to increase, and the loss of a single string of modules is also increasing. Now, modules often use a method of cutting large-size cells into two, three, or even six to reduce the module current, reduce the internal loss of the module, and thus increase the module power.

[0003] The conventional laser scratching technology on the market is mainly based on laser ablation combined with mechanical breaking technology: first, a cutting path through the surface is processed on the back of the battery by laser, and then the battery cell is broken along the cutting path by mechanical method. Since laser cutting is based on photothermal effect, there will be a section of silicon wafer melted and recast heat-affected zone near the slotted area, and there may be cracks. These all lead to bond breakage at the edge after cutting, especially near the PN junction and the edge of the light-receiving surface, forming many dangling bonds, so that the photogenerated carriers generated by the photoelectric effect can easily form recombination at the edge. At present, it is measured that the loss of Perc battery efficiency by laser cutting reaches 0.05% / knife, and the loss of TOPCon battery efficiency reaches 0.2% / knife. The cutting damage seriously affects the packaging power loss of battery cells to components.

[0004] CN111430506A discloses a crystalline silicon solar cell and its edge passivation method, which places the sliced ​​solar cells horizontally and neatly, so that the slice sections of each solar cell are in the same plane, and then puts them into a sheet box, which is put into an alumina deposition device together with the solar cells, and a layer of alumina film is plated on the edge of the slice section of the solar cell, and then it is placed in an electric injection annealing furnace for annealing. This method can reduce the carrier recombination rate of the laser cut surface of the cell to a certain extent, but because it only plates a layer of alumina film, it has limited ability to repair damage to the solar cell after cutting; and the passivation of the invention finally adopts the method of electric injection annealing furnace, because the electric injection annealing time is 5-180min, not only the annealing time is too long, but also the possibility of defects is increased.

[0005] CN111509091A discloses a method for passivating the edge of a cell, wherein a slurry is printed on the edge of the crystalline silicon cell that needs to be passivated by coating, and ultraviolet light is irradiated on the edge to form a layer of silicon oxide passivation film on the edge under the condition of photocatalytic oxidation; the slurry contains hydrogen peroxide and SiO2 powder; after the silicon oxide passivation film is formed on all the edges that need to be passivated on the crystalline silicon cell, the crystalline silicon cell that has completed photocatalytic oxidation is annealed. The photocatalytic oxidation technology is used to passivate the edges of the crystalline silicon solar cell, thereby improving the photoelectric conversion efficiency of the cell. However, since it is only coated with a layer of silicon oxide passivation film, the ability to repair damage to the solar cell after cutting is limited.

[0006] In view of this, the present invention is proposed. Summary of the invention

[0007] One of the purposes of the present invention is to provide a solar cell with a passivation layer on the cut edge, characterized in that the solar cell is a cell after being cut and sliced; wherein a first passivation layer and a second passivation layer are sequentially deposited on the cut edge of the cell; the first passivation layer is a silicon oxide layer and / or an aluminum oxide layer; and the second passivation layer is a silicon nitride layer. By performing a double-layer passivation treatment on the edge of the cell after cutting, the efficiency loss of the cell caused by laser cutting can be effectively repaired.

[0008] The second object of the present invention is to provide a method for preparing a solar cell with a passivation layer on the cut edge. The preparation method comprises the following steps: firstly depositing a first passivation layer on the cut edge of the cell after cutting and slicing, then depositing a second passivation layer on the first passivation layer, and finally performing light injection passivation to obtain the solar cell with the passivation layer on the cut edge. The method realizes the passivation of the cut edge defects and impurities, thereby improving the efficiency of the cell.

[0009] In order to achieve the above-mentioned purpose of the present invention, the following technical solutions are particularly adopted:

[0010] In a first aspect, the present invention provides a solar cell having a passivation layer at a cut edge, wherein the solar cell is a cell after being cut and sliced;

[0011] Wherein, a first passivation layer and a second passivation layer are sequentially deposited on the cut edge of the battery;

[0012] Wherein, the first passivation layer is a silicon oxide layer and / or an aluminum oxide layer; the second passivation layer is a silicon nitride layer.

[0013] In the present invention, firstly, one or both of silicon oxide and aluminum oxide are grown on the edge of the cut small piece of battery as the first passivation layer, and then silicon nitride is grown outside the first passivation layer as the second passivation layer. With the cooperation of the two passivation layers, the cut edge defects and impurities are passivated, and the composite damage caused by cutting damage is repaired, thereby improving the efficiency of the battery cell and ultimately improving the power of the component.

[0014] Preferably, the thickness of the first passivation layer is 1-10 nm, for example, 1 nm, 2 nm, 3 nm, 4 nm, 5 nm, 6 nm, 7 nm, 8 nm, 9 nm, 10 nm, etc.

[0015] Preferably, the thickness of the second passivation layer is 20-200 nm, for example, it can be 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 120 nm, 140 nm, 160 nm, 180 nm, 200 nm, etc.

[0016] Preferably, the solar cell is selected from N-type and / or P-type cells.

[0017] Preferably, the solar cell is selected from PERC or TOPCon.

[0018] In the present invention, by passivating the edges of the cell after cutting, the efficiency loss of the cell caused by laser cutting can be effectively repaired; the efficiency of small cells after cutting of N-type, P-type or PERC, TOPCon cells can be significantly improved.

[0019] In a second aspect, the present invention provides a method for preparing a solar cell having a cut edge including a passivation layer as described in the first aspect, the preparation method comprising the following steps:

[0020] Firstly, a first passivation layer is deposited on the cut edge of the cell after slicing, and then a second passivation layer is deposited on the first passivation layer. Finally, light injection passivation is performed to obtain a solar cell whose cut edge includes a passivation layer.

[0021] The present invention provides a technology for passivation and repair of the cut edge of a cell. The cut edge is repaired by depositing a passivation layer on the cut surface of the small cell after cutting, and then a light injection process is used to further passivate the small cell to improve the passivation effect, thereby achieving the effect of repairing the damage caused by cell cutting, so that the efficiency of the small cell and the power of the module are effectively improved. The first passivation layer is composed of one or both of silicon dioxide or aluminum oxide, and the second passivation layer is a layer of silicon nitride deposited outside the first passivation layer for secondary passivation and protection. Finally, the cell is hydrogen passivated through a light injection device to achieve the effect of repairing the damage caused by laser cutting and improving the cell efficiency by more than 0.2%.

[0022] Preferably, the deposition further includes a stacking step: placing all the cut small battery pieces horizontally with their front sides facing upwards, and stacking them neatly so that the cut edge sides of the small battery pieces are on the same vertical plane.

[0023] Preferably, the number of stacks is 2-1000 pieces, for example, it can be 2 pieces, 10 pieces, 20 pieces, 40 pieces, 60 pieces, 80 pieces, 100 pieces, 150 pieces, 200 pieces, 250 pieces, 300 pieces, 350 pieces, 400 pieces, 500 pieces, 600 pieces, 700 pieces, 800 pieces, 900 pieces, 1000 pieces, etc.

[0024] Preferably, the deposition method is PECVD or ALD.

[0025] Preferably, the deposition method is PECVD, and the deposition process parameters are: pressure of 1200-2000mTorr, for example, 1200mTorr, 1300mTorr, 1400mTorr, 1500mTorr, 1600mTorr, 1700mTorr, 1800mTorr, 1900mTorr, 2000mTorr, etc.; RF power of 2000-20000watt, for example, 2000watt, 4000watt, 6000watt , 8000watt, 10000watt, 12000watt, 14000watt, 16000watt, 18000watt, 20000watt, etc.; the coating time is 100-2000s, for example, it can be 100s, 200s, 400s, 600s, 800s, 1000s, 1200s, 1400s, 1600s, 1800s, 2000s, etc.; the temperature is 300-500℃, for example, it can be 300℃, 350℃, 400℃, 450℃, 500℃, etc.

[0026] Preferably, the deposition method is ALD, and the deposition process parameters are: deposition temperature is 150-250°C, for example, it can be 150°C, 160°C, 180°C, 200°C, 220°C, 250°C, etc.; process time is 200-2000s, for example, it can be 200s, 400s, 600s, 800s, 1000s, 1200s, 1400s, 1600s, 1800s, 2000s, etc.; heating rate is 1-5°C / s, for example, it can be 1°C / s, 2°C / s, 3°C / s, 4°C / s, 5°C / s, etc.

[0027] Preferably, a light injection device is used to perform light injection passivation on the sides of the battery cell group, and the lamp tubes need to be installed on the left and right sides of the light injection device.

[0028] Preferably, the light intensity of the light injection passivation is 20-100 (for example, it can be 20, 30, 40, 50, 60, 70, 80, 90, 100, etc.) times the intensity of sunlight.

[0029] Preferably, the temperature in the furnace for light injection passivation is 200-500°C, for example, 200°C, 250°C, 300°C, 350°C, 400°C, 450°C, 500°C, etc.

[0030] Preferably, the light injection passivation time is 30-300 s, for example, it can be 30 s, 50 s, 100 s, 150 s, 200 s, 250 s, 300 s, etc.

[0031] Preferably, the solar cell cut edge passivation method specifically comprises the following steps:

[0032] (a) Depositing a passivation layer: depositing a 1-10 nm silicon oxide layer and / or aluminum oxide layer as a first passivation layer on the cut edge of the cell after dicing and slicing, and then depositing a 20-200 nm silicon nitride layer as a second passivation layer on the first passivation layer;

[0033] The deposition method is PECVD method, and the deposition process parameters are: pressure is 1200-2000mTorr; RF power is 2000-20000watt; coating time is 100-2000s; temperature is 300-500°C;

[0034] Or, the deposition method is ALD method, and the deposition process parameters are: process time 200-2000s; deposition temperature 150-250°C; heating rate 1-5°C / s;

[0035] (b) Light injection passivation: After the silicon nitride layer is deposited on the cutting edge, the battery pack is subjected to light injection passivation. The light injection equipment is used to perform light injection passivation on the sides of the battery pack. The lamp tubes need to be installed on the left and right sides of the light injection equipment.

[0036] The light intensity of the light injection passivation is 20-100 solar light intensity, the temperature in the furnace is 200-500° C., and the passivation time is 30-300 seconds.

[0037] Preferably, the solar cell cut edge passivation method specifically comprises the following steps (eg Figure 1 shown):

[0038] S1 cutting: Use laser cutting technology to divide the battery into N small pieces of batteries (such as Figure 2 shown);

[0039] S2 stacking: Place all the cut small battery pieces horizontally with their front sides facing upwards, stack them neatly so that the cut edge sides of the small battery pieces are on the same vertical plane, and assemble the neatly stacked battery pieces into a sheet box;

[0040] S3 deposits the first passivation layer: puts the stacked battery packs and the connected chip boxes together into a passivation layer deposition device, and deposits a 1-10 nm silicon oxide layer and / or aluminum oxide layer on the exposed cut edges as the first passivation layer;

[0041] S4 deposits the second passivation layer: after depositing the first passivation layer, the battery pack is placed in another lamination device, and a 20-200nm silicon nitride layer is grown outside the first passivation layer at the cut edge as the second passivation layer, and the stacking state of the small battery pack and the structure of the passivation film layer after deposition are obtained (such as Figure 3 shown);

[0042] S5 light injection passivation: light injection passivation is performed on the cell group with double passivation layer deposited (such as Figure 4 As shown), the lamp tube needs to be installed on the left and right sides of the equipment. The light intensity of the lamp tube ranges from 20 to 100 solar light intensities. The temperature in the furnace is 200 to 500°C. It needs to undergo 30 to 300 seconds of light injection passivation to obtain the solar cell with a passivation layer on the cut edge.

[0043] In the above S1, the graphic design is to cut N whole battery sheets into N (N can be 2-10, for example, 2, 3, 4, 5, 6, 7, 8, 9, 10, etc.) small battery sheets by laser cutting technology.

[0044] In the above S2, all the cut small battery pieces are placed horizontally with the front side facing upwards, and are stacked neatly so that the cut sides of the small battery pieces are on the same vertical plane. The number of stacks can be 2-1000 pieces, and the neatly stacked battery packs are placed in a sheet box. The stacked battery packs need to expose the cut edges so that the subsequent passivation process will not block the cut sides of the battery packs. The bottom and top of the battery pack are protected by baffles to make the battery cells fit tightly.

[0045] In the above S3, a layer of one or both of silicon oxide and aluminum oxide is deposited on the exposed cutting edge to form a first passivation layer, and the passivation layer can passivate the cutting edge.

[0046] In the above S4, after the first passivation layer is deposited, the battery pack is placed in another lamination device, and a silicon nitride layer is grown outside the passivation layer at the cut edge as the second passivation layer to play a passivation and protection role.

[0047] In the above S3 and S4, the deposition process of the first passivation layer and the second passivation layer may be PECVD (plasma enhanced chemical vapor deposition) or ALD (atomic deposition).

[0048] In the above S5, after the silicon nitride layer is deposited on the cutting edge, the battery pack is passivated by light injection. The normal light injection equipment performs light injection passivation on the front and back of the single-chip battery, and the lamp tubes are installed on the top and bottom of the equipment. The light injection equipment of this invention needs to passivate the sides of the battery pack, and the lamp tubes need to be installed on the left and right sides of the equipment. The light intensity of the lamp tube ranges from 20-100 suns, and the temperature in the furnace is 200-500°C. It needs to undergo 30-300s of light injection passivation to inject H ions in the edge passivation layer into the cutting edge, further improving the cutting damage and improving the efficiency of the battery chip.

[0049] Compared with the prior art, the present invention has the following beneficial effects:

[0050] (1) The present invention provides a solar cell with a cut edge including a passivation layer, which firstly grows one or both of silicon oxide and aluminum oxide as a first passivation layer on the edge of the cut small cell, then grows silicon nitride as a second passivation layer outside the first passivation layer, and finally performs annealing treatment on the passivated cell by a light injection device to passivate the cut edge defects and impurities, thereby improving the efficiency of the cell;

[0051] (2) The first passivation layer of the present invention is composed of one or both of silicon dioxide and aluminum oxide, and the second passivation layer is a layer of silicon nitride deposited outside the first passivation layer for secondary passivation and protection. Finally, the cell is hydrogen passivated by light injection equipment to repair laser cutting damage and improve cell efficiency by more than 0.2%. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0053] Figure 1 The present invention is a process flow chart of a method for preparing a solar cell with a cut edge comprising a passivation layer.

[0054] Figure 2 Schematic diagram of laser sectioning of the present invention.

[0055] Figure 3This is a diagram of the stacking state of the small battery pack of the present invention and the structure of the passivation film layer after deposition;

[0056] Among them, 1 is the battery after cutting and slicing, 2 is the first passivation layer, 3 is the second passivation layer, 4 is the chip box, 5 is the upper baffle, and 6 is the lower baffle.

[0057] Figure 4 Schematic diagram of the light injection device structure. DETAILED DESCRIPTION

[0058] Unless otherwise defined herein, scientific and technical terms used in conjunction with the present invention shall have the meanings commonly understood by those of ordinary skill in the art. The meaning and scope of the terms should be clear, however, in the case of any potential ambiguity, the definitions provided herein take precedence over any dictionary or external definitions. In this application, unless otherwise stated, the use of "or" means "and / or". In addition, the use of the term "including" and other forms is non-limiting.

[0059] Generally, the nomenclature and its technology used in conjunction with cell and tissue culture, molecular biology, immunology, microbiology, genetics, and protein and nucleic acid chemistry and hybridization described herein are those well-known and commonly used in the art. Unless otherwise indicated, the methods and techniques of the present invention are generally carried out according to conventional methods as well-known in the art, and as described in various general and more specific references, which are cited and discussed throughout this specification. Enzymatic reactions and purification techniques are carried out according to the manufacturer's specifications, as generally achieved in the art, or as described herein. The nomenclature and its laboratory procedures and technology used in conjunction with analytical chemistry, synthetic organic chemistry, and medical and pharmaceutical chemistry described herein are those well-known and commonly used in the art.

[0060] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0061] The present invention is further described below by way of examples. Unless otherwise specified, the materials in the examples are prepared according to existing methods or directly purchased from the market.

[0062] Example 1

[0063] This embodiment provides a solar cell with a cut edge including a passivation layer, and the edge passivation process method specifically includes the following steps:

[0064] S1 cutting: Using laser cutting technology, the whole 210mm×210mm P-type PERC solar cell is divided into 6 small cells; the size of the cut small cells is: 210mm long, 35mm wide, and 150μm thick;

[0065] S2 stacking: Place all the cut small battery pieces horizontally with the front side facing upwards, and stack them neatly so that the cut sides of the small battery pieces are on the same vertical plane. The number of stacks can be 500 pieces, and the neatly stacked battery packs are put into a sheet box; the stacked battery packs need to expose the cut edges so that the subsequent passivation process will not block the cut sides of the battery packs;

[0066] S3: Deposit the first passivation layer: Place the stacked battery packs and the connected chip boxes together into a passivation layer deposition device, and deposit a 5 nm aluminum oxide layer on the exposed cut edges as the first passivation layer;

[0067] The deposition adopts PECVD method, and the deposition process parameters are: pressure of 1500mTorr; RF power of 6000watt; time of 100s; temperature of 350°C; N2O flow rate of 5.5slm; TMA flow rate of 0.05sccm;

[0068] S4 deposits the second passivation layer: after depositing the first passivation layer, the battery pack is placed in another lamination device, and an 80nm silicon nitride layer is grown outside the first passivation layer at the cut edge as the second passivation layer;

[0069] The deposition adopts PECVD method, and the deposition process parameters are: pressure is 1800mTorr; RF power is 10000watt; time is 800s; temperature is 450°C; NH3 flow rate is 7000sccm; SiH4 flow rate is 1200sccm;

[0070] S5 Light injection passivation: Finally, the battery pack and the cassette with two layers of passivation layers stacked are placed in the light injection equipment. The passivation layer is light injected for passivation at 200°C with a light intensity of 30 suns. The light injection time is 60 seconds.

[0071] S6 Component Production: Finally, the passivated small-piece batteries will be used to produce components.

[0072] Example 2

[0073] This embodiment provides a solar cell with a cut edge including a passivation layer, and the edge passivation process method specifically includes the following steps:

[0074] S1 cutting: Using laser cutting technology, the whole 210mm×210mm N-type TOPCon solar cell is divided into three small cells; the size of the small cells after cutting is: 210mm long, 70mm wide, and 130μm thick;

[0075] S2 stacking: Place all the cut small battery pieces horizontally with the front side facing upwards, and stack them neatly so that the cut sides of the small battery pieces are on the same vertical plane. The number of stacks can be 600 pieces, and the neatly stacked battery packs are put into a sheet box; the stacked battery packs need to expose the cut edges so that the subsequent passivation process will not block the cut sides of the battery packs;

[0076] S3 deposits the first passivation layer: the stacked battery packs and the connected chip boxes are placed together in a passivation layer deposition device, and a silicon dioxide and aluminum oxide composite film is deposited on the exposed cutting edge as the first passivation layer, and the film thickness of silicon dioxide and aluminum oxide is controlled to be 2nm;

[0077] The deposition adopts ALD method, and the deposition process parameters are: process time is 500s; deposition temperature is 200°C; heating rate is 2°C / s;

[0078] S4 deposits the second passivation layer: after depositing the first passivation layer, the battery pack is placed in another lamination device, and a 100nm silicon nitride layer is grown outside the first passivation layer at the cut edge as the second passivation layer;

[0079] The deposition adopts PECVD method, and the deposition process parameters are: pressure is 1800mbar; RF power is 11000W; time is 1000s; deposition temperature is 460°C; NH3 flow rate is 8000sccm; SiH4 flow rate is 1400sccm;

[0080] S5 Light injection passivation: Finally, the battery pack and the cassette with two layers of passivation layers stacked are placed in the light injection equipment. The passivation layer is light injected for passivation at 300°C with a light intensity of 50 suns. The light injection time is 120 seconds.

[0081] S6 Component Production: Finally, the passivated small-piece batteries will be used to produce components.

[0082] Example 3

[0083] This embodiment provides a solar cell with a cut edge including a passivation layer, which is different from Embodiment 1 only in that the thickness of the first passivation layer, the aluminum oxide layer, is 5 nm, and the thickness of the second passivation layer, the silicon nitride layer, is 80 nm.

[0084] Example 4

[0085] This embodiment provides a solar cell having a cut edge with a passivation layer, which is different from Embodiment 1 only in that the passivation layer is passivated by light injection at 300° C. with a light intensity of 10 Suns, and the light injection time is 400 s.

[0086] Example 5

[0087] This embodiment provides a solar cell having a cut edge with a passivation layer, which is different from Embodiment 1 only in that the passivation layer is passivated by light injection at 300° C. with a light intensity of 120 suns, and the light injection time is 20 seconds.

[0088] Example 6

[0089] This embodiment provides a solar cell with a cut edge including a passivation layer, which is different from the embodiment 1 only in that electric injection passivation is used, the annealing temperature in the annealing furnace is 400° C., and the annealing time is 60 min.

[0090] Comparative Example 1

[0091] This comparative example provides a solar cell with a cut edge including a passivation layer, and the edge passivation process method specifically includes the following steps:

[0092] S1 cutting: Using laser cutting technology, the whole 210mm×210mm P-type PERC solar cell is divided into 6 small cells; the size of the cut small cells is: 210mm long, 35mm wide, and 150μm thick;

[0093] S2 stacking: Place all the cut small battery pieces horizontally with the front side facing upwards, and stack them neatly so that the cut sides of the small battery pieces are on the same vertical plane. The number of stacks can be 500 pieces, and the neatly stacked battery packs are put into a sheet box; the stacked battery packs need to expose the cut edges so that the subsequent passivation process will not block the cut sides of the battery packs;

[0094] S3 Deposition of passivation layer: Place the stacked battery packs and connected chip boxes together into a passivation layer deposition device, and deposit a 10nm aluminum oxide layer as a passivation layer on the exposed cut edges;

[0095] The deposition adopts ALD method, and the deposition process parameters are: time is 1500s; temperature is 210°C; O3 flow rate is 30slm; TMA flow rate is 1500sccm;

[0096] S4 light injection passivation: Finally, the battery pack and the cassette with two layers of passivation layers stacked are placed in the light injection equipment, and the passivation layer is light injected for passivation at 200°C with a light intensity of 30 suns. The light injection time is 60 seconds.

[0097] S5 component production: Finally, the passivated small-piece batteries will be used to make components.

[0098] Comparative Example 2

[0099] This comparative example provides a solar cell with a cut edge including a passivation layer, and the edge passivation process method specifically includes the following steps:

[0100] S1 cutting: Using laser cutting technology, the whole 210mm*210mm P-type PERC solar cell is divided into 6 small cells; the size of the cut small cells is: 210mm long, 35mm wide, and 150μm thick;

[0101] S2 stacking: Place all the cut small battery pieces horizontally with the front side facing upwards, and stack them neatly so that the cut sides of the small battery pieces are on the same vertical plane. The number of stacks can be 500 pieces, and the neatly stacked battery packs are put into a sheet box; the stacked battery packs need to expose the cut edges so that the subsequent passivation process will not block the cut sides of the battery packs;

[0102] S3 Deposition of passivation layer: Place the battery pack into the deposition equipment, and grow a 90nm silicon nitride layer as a passivation layer outside the first passivation layer at the cut edge;

[0103] The deposition adopts PECVD method, and the deposition process parameters are: pressure is 1800mTorr; RF power is 11000W; time is 900s; temperature is 450°C; NH3 flow rate is 8000sccm; SiH4 flow rate is 1400sccm;

[0104] S4 light injection passivation: Finally, the battery pack and the cassette with two layers of passivation layers stacked are placed in the light injection equipment, and the passivation layer is light injected for passivation at 200°C with a light intensity of 30 suns. The light injection time is 60 seconds.

[0105] S5 component production: Finally, the passivated small-piece batteries will be used to make components.

[0106] Test Example 1

[0107] Battery performance test

[0108] Test samples: batteries provided in Examples 1-6 and batteries provided in Comparative Examples 1-2;

[0109] Test items: open circuit voltage (Voc), conversion efficiency (EFF), fill factor (FF), short circuit current (Isc) and other performance tests;

[0110] Test method: The test environment is controlled at 24±1℃ by a cooling controller, and the comprehensive electrical performance (including open circuit voltage Voc, photoelectric conversion efficiency EFF, fill factor FF, short circuit current Isc) is the data obtained by testing with a solar simulator or IV tester. The light intensity of the light source used by the solar simulator or IV tester needs to be calibrated with a "standard chip" (standard performance battery cell).

[0111] The specific test results are shown in Table 1 below:

[0112] Table 1

[0113]

[0114]

[0115] It can be seen from the test data in Table 1 that the solar cell provided by the present invention includes a passivation layer on the cutting edge. First, one or both of silicon oxide or aluminum oxide are grown on the edge of the cut small cell as the first passivation layer, and then silicon nitride is grown outside the first passivation layer as the second passivation layer. Finally, the passivated cell is annealed by a light injection device to passivate the cutting edge defects and impurities, thereby improving the efficiency of the cell. The first passivation layer of the present invention is composed of one or both of silicon dioxide or aluminum oxide, and the second passivation layer is a layer of silicon nitride deposited outside the first passivation layer for secondary passivation and protection. Finally, the cell is hydrogen passivated by a light injection device to repair the laser cutting damage and improve the cell efficiency by more than 0.2%.

[0116] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a solar cell having a cut edge including a passivation layer, characterized in that: The preparation method comprises the following steps: First, a first passivation layer is deposited on the cut edge of the cell after cutting and slicing, and then a second passivation layer is deposited on the first passivation layer, and finally light injection passivation is performed to obtain a solar cell whose cut edge includes a passivation layer; and before the deposition, a stacking step is also included: all the cut small pieces of cells are placed horizontally with the front side facing upward, and stacked neatly so that the side edges of the cut edges of the small pieces of cells are on the same vertical plane; and a light injection device is used to perform light injection passivation on the side edges of the cell group, and the lamp tube needs to be installed on the left and right sides of the light injection device; The number of stacks is 2-1000 pieces; The deposition method is PECVD or ALD; The deposition method is PECVD method, and the deposition process parameters are: pressure of 1200-2000 mTorr; RF power of 2000-20000 watt; coating time of 100-2000 s; temperature of 300-500°C; The deposition method is ALD method, and the deposition process parameters are: deposition temperature is 150-250°C; process time is 200-2000 s; heating rate is 1-5°C / s; The light intensity of the light injection passivation is 20-100 solar light intensity, the temperature in the furnace of the light injection passivation is 200-500° C., and the time of the light injection passivation is 30-300 s.

Images