Cut cell, module, and passivation coating method for side cut surface of cell

Abstract

A cut cell, a module, and a passivation coating method for a side cut surface of a cell. The coating method comprises the following steps: stacking cut cells and then placing same into a plurality of cell boxes each having a side surface provided with a processing window; transferring said cell boxes to an area for cells to be passivated, a plurality of cells being placed into each cell box; transferring the plurality of cell boxes from the area for cells to be passivated to a tray; allowing a reactant and a carrier gas to enter a reaction chamber through a gas path system; performing side cut surface passivation coating in the reaction chamber, i.e., forming a passivation film on the side cut surface of each cell by means of deposition; and when the side cut surface passivation coating is completed, transferring all of the plurality of cell boxes from the tray to an area for passivated cells. The method implements the passivation of side cut surfaces of cells, improves the efficiency of cell modules, avoids the technical problem of yield loss caused by poor welding of cell modules due to wrap-around of passivation films on the front surfaces or the back surfaces of cells, and reduces the power generation cost of the modules.

Description

Cutting battery cells and their components and passivation coating method for side sections of battery cells Technical Field

[0001] The present application relates to the field of solar cells, and in particular to a solar cell with a coated side section, a component made from the solar cell, and a method for passivating and coating the side section of a cut solar cell. Background Art

[0002] In recent years, new solar module technologies such as half-cut modules and shingled modules have become increasingly popular. When making the above-mentioned solar modules, it is necessary to split a cell into two or more pieces. In industrial applications, the methods of splitting solar cells generally include laser scribing plus mechanical cracking, thermal laser low-damage cracking, etc. The surface recombination rate of the silicon wafer cross-section (side section) formed after the cell is cut is large, which will have a negative impact on the electrical performance of the solar cell. For example, after a Topcon solar cell is split into two by laser scribing, its cross-section is an unpassivated silicon wafer cross-section. The conversion efficiency of the half-cell will be reduced by 0.2-0.3% due to the increased recombination at the edge of the cross-section. The efficiency of heterojunction solar cells will be reduced more after laser cracking due to their higher open-circuit voltage. The reduction in solar cell efficiency caused by the above-mentioned cutting will directly lead to a reduction in the power of the components made from sliced ​​cells.

[0003] Passivation coating forms a layer of film on the cell surface through deposition, reducing minority carrier recombination, providing field passivation, and lowering reflectivity. As the quality of N-type silicon wafers and cell efficiency continue to improve, the loss caused by slicing is also increasing. Numerous studies have documented that applying passivation coating to the side sections of the cell can reduce this loss.

[0004] It is generally believed that the function of the passivation film layer is to saturate the silicon floating bonds on the surface of the exposed silicon wafer and establish field passivation. These two functions can be met with a thickness of several atomic layers. Therefore, it is generally believed that the passivation film thickness is about 10nm. Chinese patent application CN 111430506 A also clearly states that the passivation film thickness is 10nm or 15nm. The document does not disclose the specific passivation effect. Solar Energy Materials and Solar Cells 258(2023)112429 holds a similar view and also believes that a film thickness of 8-14nm is sufficient to achieve the required passivation effect.

[0005] At the same time, to improve production efficiency, it is conceivable that stacking the cells and then performing cross-section passivation coating is a good option. However, the metal grid lines on the front and back of the printed cells are typically 10-30μm high. The presence of these metal grid lines creates gaps between the stacked cells. During coating, the passivation repair film can extend into these gaps, a phenomenon known as wrap-around plating. When the wrap-around coating is deposited on the solder joints on the front and back of the cells, it can cause poor contact, affecting the yield of the resulting battery assembly.

[0006] One existing solution to the wrap-around plating problem is to slice and passivate the cells before printing the metal grid lines. This allows for wrap-around plating without affecting the solder joints on the cell surface. However, this approach presents the following technical issues: 1) Cells without grid lines can be scratched by friction; 2) Printing half-cells or smaller cells (shingled cells) significantly reduces printing line capacity, increasing production line investment and significantly increasing costs.

[0007] The side-section passivation coating method disclosed in Chinese patent application CN111430506 A does not address the issue of wraparound plating, nor does it address how to address it. Figure 1 shows a photograph of a cell after coating using this prior art coating method. The wraparound plating phenomenon is quite severe, with a passivation film forming on the metal ribbon solder joints on the front and back of the cell, affecting contact between the ribbon and the metal solder joints. EL images of cell modules made from such sliced ​​cells show dark spots, reduced efficiency and reliability, and low yield (Figure 2).

[0008] The inventors have discovered that when using existing coating technology and within the disclosed coating thickness range, when the coating is deposited on the welding points on the front and back sides of the battery cell, poor contact will result, affecting the contact between the battery welding points and the welding ribbons, causing local EL dark spots, and ultimately affecting the yield of the corresponding battery components.

[0009] It can be seen that overcoming the shortcomings of the existing technology, providing an improved solar cell and its components, and a corresponding side-section passivation coating method, improving the efficiency of solar cells and their components, while ensuring the yield rate of their components and ultimately reducing the cost of component power generation, has become a technical problem that needs to be solved urgently by those skilled in the art.

[0010] Summary of the Invention

[0011] The purpose of this application is to overcome the above-mentioned defects of the prior art and to provide a side-cut passivated cut cell and its assembly, as well as a passivation coating method for the side cut of the cell, while ensuring that the printing capacity is not reduced, thereby effectively improving the efficiency of the cell. Another purpose of this application is to significantly reduce the adverse effects of wrap-around plating, improve the efficiency and yield of the corresponding battery assembly, and reduce the cost of component power generation. Furthermore, the side-cut coating method of this application can significantly reduce the wrap-around plating phenomenon and the adverse effects caused by it.

[0012] Even more unexpectedly, the inventors discovered during their research that, contrary to the general understanding of the prior art, the passivation film thickness on the side section of the cell after cutting is greater than 20nm, further greater than 25nm, and especially close to 30nm. The passivation effect is significantly improved, and then continues to rise with the increase in coating thickness, and no longer changes significantly when the coating thickness is 60-80nm. For example, compared to the baseline (BL) of the sample without side section coating passivation, the cell efficiency increases with the increase in passivation film thickness in the coating thickness range of 0-60nm. When the thickness reaches more than 60nm, the film thickness increases but the cell efficiency no longer increases, indicating that the passivation effect has reached saturation (Figure 3). The power improvement of the corresponding battery assembly shows basically the same trend (Figure 4).

[0013] To this end, the first aspect of the present application relates to a cut cell having a side cut surface coated with a passivation film of aluminum oxide, a wrapping width of 0.1-1.5 mm on the front or back of the cell, and the cut cell has completed metal grid line printing and sintering before cutting.

[0014] Preferably, the plating width on the front or back side of the battery is 0.1-1 mm.

[0015] Preferably, the thickness of the passivation film is 55-100 nm, more preferably, the thickness of the passivation film is 40-60 nm.

[0016] The second aspect of the present application also relates to a cut cell, wherein a 21-100 nm passivation film is plated on the side cut surface of the cell, and the cut cell has completed metal grid line printing and sintering before cutting.

[0017] Preferably, the thickness of the passivation film is 25-80 nm, more preferably, the thickness of the passivation film is 30-60 nm.

[0018] Preferably, the width of the plating on the front or back of the battery is 0.1-1.5 mm, more preferably, the width of the plating on the front or back of the battery is 0.1 to 1 mm.

[0019] Preferably, the material of the passivation film is any one of the following materials: aluminum oxide, silicon nitride, silicon oxynitride, silicon oxide, polycrystalline silicon, and amorphous silicon.

[0020] The third aspect of this application relates to a battery cell assembly.

[0021] The assembly comprises a plurality of cut solar cells that have been cut and then coated according to the first aspect and / or the second aspect, and is manufactured according to a known method.

[0022] A fourth aspect of the present application relates to a passivation coating method for a side section of a cut solar cell, comprising the following steps:

[0023] Step S101: stacking the cut cells and placing them into a plurality of cell boxes with processing windows on the side, placing the cell boxes in the area to be passivated, and placing a plurality of cells in each cell box;

[0024] Step S102: placing multiple wafer cassettes from the area to be passivated onto a tray in the reaction chamber;

[0025] Step S103: reactants and carrier gas enter the reaction chamber through the gas system;

[0026] Step S104: performing a passivation coating on the side surface in a reaction chamber, i.e. forming a passivation film on the side surface of the cell by deposition, with a reaction temperature of 100-500° C. and a reaction pressure of 0-200 Torr;

[0027] Step S105: After the passivation coating of the side sections is completed, multiple cassettes are placed from the tray into the passivated area.

[0028] Preferably, in step S101, each cell box contains 10-2000 cells.

[0029] Preferably, in step S101, each cell box contains 200-600 cells.

[0030] Preferably, before step S101, the method further includes step S100: cutting the printed and sintered solar cells;

[0031] Preferably, laser scribing is used when cutting the battery cell, and water spraying is used to perform the splitting during the laser scribing.

[0032] Preferably, after step S105, an oxygen-free cooling step is further performed to cool the cell after the passivation film is formed to room temperature in an oxygen-free environment.

[0033] Preferably, an annealing step is performed between step S104 and step S105 .

[0034] Preferably, in step S104, the reaction temperature is 100-300° C., and the reaction pressure is 0-100 Torr.

[0035] Compared with the prior art, this application has the following advantages:

[0036] According to the cell and module, as well as the side-section passivation coating method provided in this application, the conversion efficiency loss caused by cell cutting can be reduced, and the adverse effects caused by wrap-around plating can be significantly reduced, thereby improving the efficiency of the cell module and reducing the cost of module power generation. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] FIG1 is a schematic diagram of a solar cell after coating using conventional technology.

[0038] In Figure 2, (a) is a front view of a cell with wrap-around plating using existing technology, and (b) is an EL image of a battery module made with a cell containing wrap-around plating. The wrap-around plating part affects the contact between the battery solder joints and the solder ribbons, resulting in local EL dark spots.

[0039] FIG3 is a graph showing the relationship between the coating thickness of the side section after slicing and the battery efficiency gain.

[0040] FIG4 is a graph showing the relationship between the coating thickness of the side section after slicing and the power gain of the battery module.

[0041] FIG5 is a schematic structural diagram of the device used in the side-section passivation coating method of the present application.

[0042] FIG6 is a schematic diagram of a wafer cassette used in the side-section passivation coating method of the present application.

[0043] FIG7 is a flow chart of the side-section passivation coating method of the present application.

[0044] FIG8 is a schematic diagram of the placement of the film cassette in the coating method of the present application.

[0045] FIG9 is another schematic diagram of the arrangement of the film cassettes in the coating method of the present application.

[0046] FIG. 10 is a schematic diagram of a solar cell after being coated using the side-section passivation coating method in FIG. 7 . DETAILED DESCRIPTION

[0047] The technical solutions in the embodiments of the present application will be described in detail below in conjunction with the drawings in the embodiments of the present application. Obviously, the following embodiments are only some specific implementation methods of the present application, but not all embodiments. The following exemplary embodiment descriptions are only illustrative and do not limit the present application and its application or use. Based on the description of this application, all other technical solutions obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0048] For ease of description, this application uses spatially relative terms, such as "above", "above", "on the upper surface of", "above", etc., to describe the spatial positional relationship of a device or feature with other devices or features as shown in the figures. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figures. For example, if the device in the drawings is inverted, the device described as "above" or "above" will be positioned as "below" or "below". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0049] The first aspect of the present application relates to a cut cell, wherein a passivation film of aluminum oxide is plated on the side cut surface of the cell, the coating width of the front or back of the cell is 0.1-1.5 mm, and the cut cell has completed metal grid line printing and sintering before cutting.

[0050] Preferably, the plating width on the front or back of the battery is 0.1-1 mm.

[0051] A passivation film with a thickness of 55-100 nm is plated on its side section. Preferably, the thickness of the passivation film is 40-60 nm.

[0052] The second aspect of the present application also relates to another type of cut cell, wherein a 55-100 nm aluminum oxide passivation film is plated on the side cut surface of the cell, and the cut cell has completed metal grid line printing and sintering before cutting.

[0053] Preferably, the thickness of the passivation film is 40-60 nm.

[0054] Preferably, the width of the plating around the front or back of the battery is 0.1-1.5 mm, and more preferably, the width of the plating around the front or back of the battery is 0.1-1 mm.

[0055] The third aspect of the present application relates to a battery assembly, which is manufactured from a plurality of cut battery cells involved in the first aspect and / or the second aspect of the present application according to known techniques.

[0056] The fourth aspect of the present application relates to a method for passivation coating the side section of a cut battery cell. As shown in FIG2 , the device used in the side section passivation coating method of the present application includes a reaction chamber 1, a spray 2, a rotating device 3, a tray 4, a heater 5, and an air path system.

[0057] As shown in Figure 5, the reaction chamber 1 is preferably a circular chamber, but is not limited thereto and may be of other shapes according to actual needs. The reaction chamber 1 shown in Figure 5 is composed of an upper cover 6, side parts 7, and a bottom 8, and may also include other components as needed.

[0058] Spray 2 adopts a showerhead with a downward spray mode, and provides reactants for side-section passivation coating together with the gas system. The gas system preferably includes: a first deposition gas pipeline, a second deposition gas pipeline, and a purge / supplementary gas pipeline. The gas system also preferably includes a temperature control and rehydration system. The first deposition gas pipeline (the second deposition gas pipeline) is composed of, for example, an MFC (gas flow controller), a source bottle, a pneumatic valve, a connecting pipeline, etc., and may also include a PC (pressure controller). The purge / supplementary gas pipeline is composed of, for example, an MFC (gas flow controller), a pneumatic valve, a connecting pipeline, etc.

[0059] The reactants are preferably TMAl (trimethylaluminum) and H2O, but are not limited thereto. Depending on the specific coating, other suitable reactants may also be used, such as triethylaluminum, ethylaluminum dichloride, diethylaluminum monochloride, and other aluminum-containing metal organics, O3, H2O2, and O2-containing gaseous substances after plasma ionization. TMAl and H2O flow into the source bottle through a centralized liquid supply method, and then an inert gas such as N2 or Ar is used as a carrier gas. After the carrier gas enters the source bottle, TMAl and H2O will be carried out according to the saturated vapor pressure and the principle of the bubbling method, and enter the reaction chamber 1. When TMAl and H2O are used as reactants and N2 is used as the carrier gas, the passivation film formed is AlOx, but the passivation film is not limited to AlOx and may also be other suitable substances such as poly-Si, SiOx, and SiNx.

[0060] As shown in Figure 5, the rotating device 3 is arranged at the bottom of the reaction chamber 1. The rotating device 3 preferably includes a rotating shaft and a motor, but may also include other components as needed. The tray 4 is arranged above the rotating device 3, and the bottom of the tray 4 is connected to the rotating device 3, and the rotating device 3 causes the tray 4 to rotate. In the reaction chamber 1, the tray 4 is opposite to the spray 2, that is, the lower surface (gas outlet surface) of the spray 2 shown in Figure 2 is arranged opposite to the upper surface of the tray 4. The material of the tray 4 is preferably graphite, metal, etc., but is not limited to this. Any other suitable material can also be used according to actual circumstances. Multiple film boxes A can be placed on the tray 4. The distance between the lower surface of the spray 2 and the upper surface of the tray 4 can be 1.0-50 cm, and the height of the film box A can be 0.2-30 cm. Therefore, the distance between the upper end surface of the film box A and the gas outlet surface of the spray 2 can be 0.8-20 cm.

[0061] During side-section coating, the wafer cassette A is used to hold and protect the cut solar cells whose side sections require passivation. Each wafer cassette A can hold, for example, 10-2000 cut solar cells, preferably 200-600 cells. The solar cells within the wafer cassette A are positioned as close together as possible while ensuring no damage. As shown in FIG6 , a processing window is provided on the side of the wafer cassette A to expose the side sections of the solar cells to the passivation coating atmosphere during coating. The number of wafer cassettes A is 2 or more, preferably 4 or more, more preferably 8 or more, or any number as needed.

[0062] The cassette A can be positioned within the reaction chamber at any angle and in any manner suitable for film deposition. The cassette A can be placed on the tray 4 in a variety of ways, such as facing the center of the tray, facing away from the center of the tray, rotating the windward side, or rotating the leeward side. The placement angle can be, for example, perpendicular to the plane of the tray.

[0063] The total number of cells in the cassettes A placed on the tray 4 can reach several thousand, and the combined weight of the tray 4, cassettes A, and cells can reach 100 kg or more. In this case, the rotating device 3 is equipped with a drive device sufficient to ensure rotation. Preferably, when the weight of the cassettes A and cells exceeds 10 kg, a fixing device capable of securing the tray 4 to the rotating device is also included to ensure stable rotation of the tray 4.

[0064] Heaters 5 are provided at the bottom and sides of the tray 4 to maintain the reaction temperature, and heating elements are included inside the heaters 5. The heaters 5 provided at the bottom and the heaters 5 provided at the sides are preferably of an integrated structure. The heater 5 provided at the bottom can preferably heat the reaction chamber to 450°C or even higher, and the heater 5 provided at the sides can preferably achieve uniform heating in the vertical height. For example, from the bottom to the top, the heating intensity of the heater 5 increases with increasing height. For example, the number of heating elements increases with increasing height. The heating element can be, for example, a resistance wire, or any other suitable element. Preferably, the temperature difference between the lower end surface and the upper end surface of the chip box A is within 5 degrees. More preferably, as shown in FIG5 , a heater 5 is also provided below the upper cover 6 to enhance the uniform heating in the reaction chamber 1. However, this is not limited to this, and a heater 5 may not be provided below the upper cover 6.

[0065] Preferably, a valve opening is provided on the side 7 of the reaction chamber 1, which is connected to a transport system through the valve opening. A transport mechanism operates between the valve opening and the transport system, such as a conveyor belt. The transport mechanism is preferably a gripper, such as a cantilever gripper, which places a cassette A containing unpassivated cells into the tray 4 and removes a cassette A containing passivated cells from the tray 4. The cantilever gripper is adapted to the cassette A to achieve the desired movement of the cassette A within the reaction chamber, including but not limited to lifting, lowering, or parallel translation of the cassette A.

[0066] In addition, an exhaust system 9 is provided to exhaust gases generated during the passivation coating process. This exhaust system 9 is connected to a vacuum pump to ensure the vacuum level within the chamber. The exhaust system 9 includes an exhaust device located at the bottom 8 and an exhaust channel located at the side 7. The exhaust device ensures that the airflow is essentially smooth under reaction conditions, eliminating dead zones. As shown in FIG5 , the exhaust channel is at substantially the same height as the tray 4.

[0067] As shown in Figure 5, a heat source 10 for maintaining the temperature is also included, located between the shower 2 and the upper cover 6. This source is used to generate plasma to assist in film deposition. The heat source 10, for example, can be a heater and assist in film deposition methods such as ALD. However, the heat source 10 is not required and may not be provided.

[0068] In addition, a power supply device is provided to supply power to the entire passivation coating equipment. The power supply device is preferably an electrical cabinet, but may also be other suitable power supply devices.

[0069] As shown in FIG7 , the specific process of the coating method involved in the third aspect of the present application is that step S100 is first performed to cut the battery cell. The cutting can be performed by laser cracking, but is not limited to this, and other suitable cutting methods can also be used. Then step S101 is performed, the cut battery cells are stacked and placed in multiple chip boxes with processing windows on the side, and the chip boxes containing the battery cells are placed in the area to be passivated, and each chip box is placed in a plurality of battery cells. Then step S102 is performed, and multiple chip boxes are placed on the tray from the area to be passivated. Then step S103 is performed, and the reactants and carrier gas enter the reaction chamber through the gas path system. Then step S104 is performed, and side-section passivation coating is performed in the reaction chamber, that is, a passivation film is formed on the side section of the battery cell by deposition. Finally, step S105 is performed, and after the side-section passivation coating is completed, all multiple chip boxes are placed from the tray to the passivated area.

[0070] In addition, step S100 is not necessary. The coating method can be implemented by directly performing steps S101 to S105 on the cut solar cells without performing step S100.

[0071] Preferably, when performing step S100, laser scribing is used when cutting the cell, and water spraying is used to break the cell during laser scribing. The water spraying can remove contamination on the cell surface to obtain a cell surface that meets cleanliness requirements, thereby further facilitating the reduction of wraparound during coating.

[0072] Preferably, after step S105, an oxygen-free cooling step is performed to cool the cell to room temperature in an oxygen-free environment after the passivation film is formed. This refers to cooling the cell from the deposition temperature to room temperature in an oxygen-free state, meaning it is free from contact with air. This prevents oxygen in the air from oxidizing the metal grid lines on the cell at high temperatures, thereby preventing such oxidation from affecting subsequent component packaging.

[0073] Preferably, an annealing step is performed between step S104 and step S105, and an annealing process is performed at an annealing temperature of 100-450°C.

[0074] Preferably, in step S104, the reaction temperature is 100-600° C., and the reaction pressure is 0-200 Torr, more preferably the reaction temperature is 100-300° C., and the reaction pressure is 0-100 Torr.

[0075] After applying the above-mentioned coating method to the side sections, the cut solar cells of the present application were obtained. Testing has shown that the efficiency of the solar cells is significantly improved after the passivation coating process of the present application. For example, the efficiency of a 144-cell module composed of 182mm*91mm silicon wafers has increased by 6W.

[0076] The coating method of the present application is further described below based on examples.

[0077] Example 1

[0078] The coating apparatus includes a circular reaction chamber 1, a sprayer 2 with an upper spray mode, a rotating device 3 including a rotating shaft and a motor, a graphite tray 4, heaters 5 located on the bottom and sides of the tray 4, and a gas system. The circular reaction chamber 1 consists of an upper cover 6, side panels 7, and a bottom 8. There are no valve openings on the side panels 7 of the circular reaction chamber 1. The heaters 5 located on the bottom and sides of the tray 4 are separate components, and the apparatus does not include a heat source for heat retention.

[0079] First, cut the printed and sintered cells in half, align the side cuts, and place them in eight cell boxes. Stack them tightly, ensuring they do not damage the cells. Each box holds 10 cells, and the cell boxes are placed in the area to be passivated. Then, place the eight cell boxes from the passivation area onto tray 4 and arrange them as shown in Figure 8. The gap between the lower surface of spray 2 and the upper surface of tray 4 is 11 cm. The cell boxes are 10 cm high, and the gap between the upper surface of the cell boxes and the lower surface of spray 2 is 1 cm.

[0080] The reactants are TMAl (trimethylaluminum) and H2O, and the carrier gas is N2, which enters the reaction chamber through the gas system. TMAl and H2O flow into the gas system through a centralized liquid supply method. After N2 enters the gas system, TMAl and H2O will be carried out according to the saturated vapor pressure and the principle of the bubbling method and enter the reaction chamber 1. TMAl and H2O use N2 as the carrier gas and undergo a CVD reaction after entering the reaction chamber 1. The process reaction time is 5 minutes, and the passivation film formed on the side section is Al2O3 with a thickness of 35nm. During the reaction, the reaction temperature is 200°C, the flow rate of N2 carrying TMAl is 500sccm, the flow rate of N2 carrying H2O is 300sccm, the flow rate of N2 purge gas is 5slm, and the chamber pressure is 20Torr.

[0081] After the side section passivation coating is completed, all 8 cassettes are placed from tray 4 into the passivated area.

[0082] After the side-section passivation coating was completed using the coating method of Example 1, the cell was tested as shown in FIG10 and had almost no wrap-around coating, with the front side wrap-around coating at 0.7 mm and the back side wrap-around coating at 0.5 mm. Furthermore, no dark spots of EL appeared in the 72-piece module.

[0083] Example 2

[0084] The apparatus used in Example 2 is similar to that in Example 1, except that a valve opening is provided on the side 7 of the circular reaction chamber 1, which is connected to the conveyor belt through the valve opening. The heater 5 located on the bottom of the tray 4 and the heater 5 located on the side of the tray 4 are integrated and equipped with a fixing device.

[0085] First, stack the halved battery cells and place them in 12 cell boxes. Stack them tightly without damaging the battery cells. Each cell box is loaded with 500 battery cells. The cell boxes containing the battery cells are placed in the area to be passivated. Then, place the 12 cell boxes from the area to be passivated onto the tray 4. Figure 9 shows how the 12 cell boxes are placed. The distance between the lower surface of the spray 2 and the upper surface of the tray 4 is 10.8 cm, the height of the cell box is 10 cm, and the distance between the upper surface of the cell box and the lower surface of the spray 2 is 0.8 cm. Through the valve opening, the cantilever gripper places the cell box containing the unpassivated cell cells from the area to be passivated into the tray 4, and takes the cell box containing the passivated cell cells out of the tray 4. The cantilever gripper is adapted to the cell box to move the cell box, and can lift, put down, and move the cell box back and forth.

[0086] The reactants are TMAl and H2O, and the carrier gas is N2, which enters the reaction chamber through the gas system. TMAl and H2O flow into the gas system through a centralized liquid supply method. After N2 enters the gas system, TMAl and H2O will be carried out according to the saturated vapor pressure and the principle of the bubbling method and enter the reaction chamber 1. TMAl and H2O use N2 as the carrier gas and undergo a CVD reaction after entering the reaction chamber 1. The reaction time is 20 minutes, and the passivation film formed is Al2O3 with a thickness of 50nm. During the reaction process, the reaction temperature is 250°C and the chamber pressure is 5Torr. After completing the Al2O3 deposition, annealing is also carried out for 30 minutes at an annealing temperature of 300°C.

[0087] After the side section coating is completed, all 12 cassettes are placed from tray 4 into the passivated area.

[0088] After the side section is coated using the coating method of Example 2, there is almost no wrap-around coating as shown in FIG10 . The front side is coated at 0.5 mm and the back side is coated at 0.4 mm. The size of the side section after passivation is 182 mm × 91 mm. The absolute value of the power of the 144-piece module (72-plate type) packaged by these half-cell batteries is increased to 6W.

[0089] The table below shows the test results for 144 modules packaged with 82mm×91mm half-cell cells. Power is measured in W, short-circuit current is measured in A, open-circuit voltage is measured in V, and series resistance is measured in Ω. The fill factor represents the ratio of the cell's maximum output power to the incident light power. In the table below, the control group refers to modules in which half-cell cells were not passivated and packaged. The 55nm group refers to modules packaged with half-cell cells after passivation coating using the method described in Example 2. The 70nm group refers to modules packaged with half-cell cells after passivation coating using the method described in Example 2.

[0090] It can be seen that according to the coating method of the present application, the side-section coating repair of the printed battery cell is performed to reduce the wrap-around plating, which can repair the cutting loss of the cut battery cell, solve the technical problems of wrap-around plating on the cut battery cell and loss of battery efficiency caused by cutting the battery cell, improve the efficiency of the battery cell assembly, and reduce the assembly power generation cost.

[0091] While the embodiments of the present application have been described in detail above, it will be apparent to those skilled in the art that various modifications and variations may be made to these embodiments. However, it should be understood that such modifications and variations are within the scope and spirit of the present application as set forth in the claims. Furthermore, the present application described herein may have other embodiments and may be implemented or carried out in a variety of ways.

Claims

1. A method for cutting a battery cell, characterized in that: A passivation film of aluminum oxide is plated on the side cut surface of the cell, the width of the plating on the front or back of the cell is 0.1-1.5mm, and the metal grid line printing and sintering have been completed before the cell is cut.

2. The cutting cell according to claim 1, characterized in that: The plating width on the front or back of the battery is 0.1-1.0mm.

3. The cutting cell according to claim 1, characterized in that: The thickness of the passivation film is 55-100nm.

4. The cutting cell according to claim 3, characterized in that: The thickness of the passivation film is 40-60nm.

5. A method for cutting a battery cell, characterized in that: A 55-100nm aluminum oxide passivation film is plated on the side cut surface of the cell, and the cut cell has completed metal grid line printing and sintering before cutting.

6. The cutting cell according to claim 5, characterized in that: The thickness of the passivation film is 40-60nm.

7. The cutting cell according to claim 5, characterized in that: The plating width on the front or back of the battery is 0.1-1.5mm.

8. The cut battery sheet according to claim 7, characterized in that: The plating width on the front or back of the battery is 0.1-1.0mm.

9. A battery assembly, characterized in that: It is made by using the cut battery sheet described in any one of claims 1-8.

10. A passivation coating method for a side section of a battery cell, characterized in that: The following steps are involved: Step S101: stacking the cut solar cells and placing them into a plurality of cell boxes with processing windows on the side, placing the cell boxes containing the solar cells in the area to be passivated, and placing a plurality of solar cells in each cell box; Step S102: placing a plurality of wafer cassettes from the area to be passivated onto a tray in the reaction chamber; Step S103: reactants and carrier gas enter the reaction chamber through the gas path system; Step S104: performing a passivation coating on the side cut surface in a reaction chamber, that is, forming a passivation film on the side cut surface of the cell by deposition, with a reaction temperature of 100-500° C. and a reaction pressure of 0-200 Torr; Step S105: After the passivation coating of the side cut surface is completed, multiple film boxes are placed from the tray to the passivated area.

11. The passivation coating method according to claim 10, characterized in that: Before step S101, there is also step S100: cutting the battery cell.

12. The passivation coating method according to claim 10 or 11, characterized in that: The metal grid lines have been printed and sintered before the cell is cut.

13. The passivation coating method according to claim 10 or 11, characterized in that: In step S101, 10-2000 battery cells are placed in each cell box.

14. The passivation coating method according to claim 10 or 11, characterized in that: In step S101, 200-600 battery cells are placed in each cell box.

15. The passivation coating method according to claim 11, characterized in that: Laser scribing is used to cut the battery cells, and water spraying is used to split the cells during laser scribing.

16. The passivation coating method according to claim 10 or 11, characterized in that: After step S105, an oxygen-free cooling step is further performed to cool the cell after the passivation film is formed to room temperature in an oxygen-free environment.

17. The passivation coating method according to claim 10 or 11, characterized in that: An annealing step is further performed between step S104 and step S105 to perform annealing processing.

18. The passivation coating method according to claim 10 or 11, characterized in that: In step S104, the reaction temperature is 100-300° C., and the reaction pressure is 0-200 Torr.

19. A method for cutting a battery cell, characterized in that: The invention relates to a cut solar cell obtained by a passivation coating method according to any one of claims 10 to 18.

20. The cut battery sheet according to claim 19, characterized in that: The plating width on the front or back of the battery is 0.1-1.5mm.

21. The cut battery sheet according to claim 20, characterized in that: The plating width on the front or back of the battery is 0.1-1mm.

22. The cut battery sheet according to claim 19, characterized in that: The thickness of the passivation film is 55-100nm.

23. The cut battery sheet according to claim 22, characterized in that: The thickness of the passivation film is 40-60nm.

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