Passivation coating equipment and method for side section of battery piece

Abstract

The invention discloses passivation coating equipment and method for side sections of battery pieces, and the coating method comprises the following steps: stacking the cut battery pieces, putting the stacked battery pieces into a plurality of piece boxes with processing windows on the side surfaces, putting the piece boxes in which the battery pieces are put into an area to be passivated, and putting a plurality of battery pieces into each piece box; placing the plurality of wafer cassettes on a tray from the to-be-passivated area; reactants and carrier gas enter the reaction chamber through the gas path system; performing side section passivation coating in the reaction chamber, namely forming a passivation film on the side section of the battery piece in a deposition mode; and after passivation and coating of the side sections are completed, the multiple piece boxes are all placed in a passivated area from the tray. According to the invention, the passivation of the side section of the cut battery piece is realized, the efficiency of the battery assembly is improved, the technical problem of yield loss caused by poor welding of the battery assembly due to the winding plating of a passivation film on the front surface or the back surface of the battery is avoided, and the power generation cost of the assembly is reduced.

Description

[0001] This application is a divisional application of a Chinese invention patent application filed on September 13, 2023, with application number 202311175922.1 and titled “Method for cutting battery cells and their components and passivation coating of side sections of battery cells”. Technical Field

[0002] The present invention relates to the field of solar cells, and in particular to a passivation coating device and method for a side section of a solar cell. Background Art

[0003] 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 its 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.

[0004] Passivation coating refers to forming a passivation film on the surface of the cell by deposition, which plays a role in reducing minority carrier recombination, providing field passivation effect, and reducing reflectivity. As the quality of N-type silicon wafers and cell efficiency are getting higher and higher, the loss caused by cutting is also getting bigger and bigger. There are many documents that have recorded that this loss can be reduced by passivation coating the cross section of the silicon wafer on the side of the cell.

[0005] 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, and these two functions can be satisfied at a thickness of several atomic layers. Therefore, it is generally believed that the thickness of the passivation film is about 10nm. Chinese patent application CN 111430506A also clearly states that the thickness of the passivation film is 10nm or 15nm. The document does not disclose the specific passivation effect. Solar Energy Materials and Solar Cells 258 (2023) 112429 has a similar view, and also believes that a film thickness of 8-14nm is sufficient to achieve the desired passivation effect.

[0006] At the same time, in order to improve production efficiency, it is conceivable that stacking the cells and then performing cross-section passivation coating is a good choice. However, the height of the metal grid lines on the front and back of the printed cells is usually 10-30μm. The presence of these metal grid lines causes gaps between the stacked cells. During coating, the passivation repair film will extend into these gaps, a phenomenon known as wrap-around coating. When the wrap-around coating is deposited on the welding points on the front and back of the cell, it will cause poor contact and affect the yield of the corresponding battery assembly.

[0007] Regarding the problem of wrapping plating, one solution in the prior art is to slice and passivate the cell before printing the metal grid lines, and then print the cell, so that wrapping plating does not affect the welding points on the cell surface. However, this treatment method will cause the following technical problems: 1) Cells without grid lines will be scratched due to mutual friction; 2) When printing half a cell or smaller cell (shingled), the production capacity of the printing line will be significantly reduced, thereby increasing the investment in the production line and causing a significant increase in costs.

[0008] The side-section passivation coating method disclosed in Chinese patent application CN111430506 A does not mention the problem of wrap-around plating, let alone how to solve the problem. Figure 1 The following is a photo of a cell after coating according to the coating method of the prior art. It can be seen that the wrapping phenomenon is quite serious. A passivation film is formed on the metal welding points of the front and back of the cell, thereby affecting the contact between the welding point and the metal welding point. The EL picture of the cell assembly made of such sliced ​​cells shows black spots, the efficiency and reliability are reduced, and the yield rate is low ( Figure 2 ).

[0009] It can be seen that overcoming the shortcomings of the prior art, 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 the 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. Summary of the invention

[0010] The purpose of the present invention is to overcome the above-mentioned defects of the prior art, and to provide a cut cell with side-cut passivation 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, so as to effectively improve the efficiency of the cell. Another purpose of the present invention is to significantly reduce the adverse effects of the winding plating, improve the efficiency and yield of the corresponding cell assembly, and reduce the cost of power generation of the assembly.

[0011] The inventors have found that when the existing coating technology is used and the coating thickness range disclosed by the inventors is within the range, the coating is deposited around the welding points on the front and back sides of the battery cell, resulting in poor contact, affecting the contact between the battery welding points and the welding strip, causing local EL dark spots, and ultimately affecting the yield of the corresponding battery assembly. The side section coating method of the present invention can significantly reduce the phenomenon of wrap-around plating and the adverse effects caused by it.

[0012] More surprisingly, the inventors found during the research that, unlike the general understanding of the prior art, the passivation film thickness of 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 of coating thickness, and no longer changes significantly when the coating thickness is 60-80nm. For example, compared with the baseline (BL) of the sample without side section coating passivation after cutting in half, the coating thickness is in the range of 0-60nm, and the cell efficiency increases with the increase of passivation film thickness. 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 components shows basically the same trend ( Figure 4 ).

[0013] To this end, the first aspect of the present invention relates to a side-section passivation coating device for a battery cell, comprising:

[0014] A reaction chamber for coating;

[0015] Spray, located at the upper part of the reaction chamber;

[0016] A rotating device, disposed at the bottom of the reaction chamber;

[0017] A tray, arranged above the rotating device and opposite to the spray, for placing a plurality of cell boxes containing cut cell sheets;

[0018] A heater, disposed on the bottom and sides of the tray and including heating elements therein;

[0019] A gas system connected to the spray to provide reactants for coating;

[0020] The exhaust system is used to ensure the vacuum degree of the reaction chamber and the stability of the reaction gas flow.

[0021] The spray plate is in downward spray mode.

[0022] The spray plate and gas system together provide the reactants for coating.

[0023] The gas circuit system includes: a first sediment gas pipeline, a second sediment gas pipeline, and a purge / supplement gas pipeline.

[0024] For the heater installed on the side, the heating intensity increases with the height from the bottom to the top.

[0025] The side-cut passivation coating equipment of the battery cell is used to coat the side-cut of the battery cell after cutting.

[0026] Preferably, the first deposition gas pipeline and the second deposition gas pipeline are both composed of a gas flow controller, a source bottle, a pneumatic valve, a connecting pipeline, and a pressure controller.

[0027] Preferably, the gas circuit system also includes a temperature control and fluid replenishment system.

[0028] Preferably, the tray is made of graphite or metal, and the number of the sheet boxes is greater than or equal to 2.

[0029] Preferably, the reaction chamber is a circular chamber and comprises: an upper cover, a side portion, and a bottom portion.

[0030] Preferably, a heater is also provided below the upper cover.

[0031] Preferably, a valve opening is provided on the side of the reaction chamber, which is connected to a transmission system through the valve opening, and an operation is performed between the valve opening and the transmission system through a transmission mechanism.

[0032] Preferably, the transport mechanism is a gripper, which is adapted to fit the film box so as to move the film box.

[0033] Preferably, it also includes a fixing device provided on the rotating device and the tray,

[0034] The rotating device includes a rotating shaft and a motor.

[0035] The second aspect of the present invention relates to a passivation coating method for a side section of a cell after cutting, comprising the following steps:

[0036] 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;

[0037] Step S102: placing a plurality of wafer cassettes from the area to be passivated onto a tray in the reaction chamber;

[0038] Step S103: reactants and carrier gas enter the reaction chamber through the gas path system;

[0039] 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;

[0040] 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.

[0041] Preferably, in step S101, 10-2000 battery cells are placed in each cell box.

[0042] Preferably, in step S101, 200-600 battery cells are placed in each cell box.

[0043] Preferably, before step S101, the method further comprises step S100: cutting the battery cell after printing and sintering;

[0044] Preferably, after step S100 and before step S101, a cleaning step is further performed to clean the cut battery cells.

[0045] 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.

[0046] Preferably, an annealing step is performed between step S104 and step S105 .

[0047] Preferably, in step S104, the reaction temperature is 100-300° C., and the reaction pressure is 0-100 Torr.

[0048] Compared with the prior art, the present invention has the following advantages:

[0049] The passivation coating equipment and method for the side section of the battery cell provided by the present invention can reduce the conversion efficiency loss caused by battery cell cutting, and can also significantly reduce the adverse effects caused by wrap-around plating, thereby improving the efficiency of the battery cell assembly and reducing the assembly power generation cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 It is a schematic diagram of a solar cell after coating using the existing technology.

[0051] Figure 2 In the figure, (a) is a front view of a cell with wrap-around plating using the prior art, and (b) is an EL image of a battery module made with a cell with wrap-around plating. The wrap-around plating part affects the contact between the battery solder joint and the solder ribbon, resulting in local EL dark spots.

[0052] Figure 3 This is a graph showing the relationship between the coating thickness on the side section after slicing and the battery efficiency gain.

[0053] Figure 4 This is a graph showing the relationship between the coating thickness on the side section after slicing and the power gain of the battery module.

[0054] Figure 5It is a schematic structural diagram of the device used in the side-section passivation coating method of the present invention.

[0055] Figure 6 A schematic diagram of a film box used in the side-section passivation coating method of the present invention.

[0056] Figure 7 The figure is a flow chart of the side-section passivation coating method of the present invention.

[0057] Figure 8 It is a schematic diagram of the arrangement of the film box in the coating method of the present invention.

[0058] Fig. 9 Another schematic diagram of the arrangement of the film box in the coating method of the present invention.

[0059] Fig.10 For use Figure 7 Schematic diagram of a cell after being coated using the side-section passivation coating method. DETAILED DESCRIPTION

[0060] The technical solutions in the embodiments of the present invention will be described in detail below in conjunction with the drawings in the embodiments of the present invention. Obviously, the following embodiments are only some specific implementation methods of the present invention, but not all embodiments. The following exemplary embodiment description is only illustrative and is not a limitation on the present invention and its application or use. Based on the description of the present invention, all other technical solutions obtained by ordinary technicians in the field without creative labor belong to the scope of protection of the present invention.

[0061] For ease of description, the present invention uses spatially relative terms, such as "above", "above", "on the upper surface of", "above", etc., to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figures. It should be understood that the spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying 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.

[0062] The first aspect of the present invention relates to a cut cell, wherein a passivation film is plated on the side cut surface of the cell, the width of the wrapping plating on the front or back of the cell is 0.1-1.5mm, and the cut cell has completed metal grid line printing and sintering before cutting.

[0063] Preferably, the plating width on the front or back side of the battery is 0.1-1 mm.

[0064] A passivation film with a thickness of 8-100 nm is plated on its side section. Preferably, the thickness of the passivation film is 15-80 nm. More preferably, the thickness of the passivation film is 25-60 nm.

[0065] The second aspect of the present invention also relates to another 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.

[0066] Preferably, the thickness of the passivation film is 25-80 nm. More preferably, the thickness of the passivation film is 30-60 nm.

[0067] Preferably, the plating width on the front or back side of the battery is 0.1-1.5 mm, and more preferably, the plating width on the front or back side of the battery is 0.1-1 mm.

[0068] Preferably, the material of the passivation film is any one of the following materials: aluminum oxide, silicon nitride, polysilicon, amorphous silicon. The material of the passivation film is preferably aluminum oxide, but is not limited thereto, and may also be other suitable materials.

[0069] The third aspect of the present invention relates to a battery assembly, which is manufactured from a plurality of cut battery sheets according to the first aspect and / or the second aspect of the present invention according to known techniques.

[0070] A fourth aspect of the present invention relates to a method for passivating a side section of a cell after cutting. Figure 2 As shown, the device used in the side-section passivation coating method of the present invention includes a reaction chamber 1, a spray 2, a rotating device 3, a tray 4, a heater 5, and a gas path system.

[0071] like Figure 5 As shown, the reaction chamber 1 is preferably a circular chamber, but is not limited thereto and may be other shapes according to actual needs. Figure 5 The reaction chamber 1 shown is composed of an upper cover 6, a side portion 7, and a bottom portion 8, and may also include other components as required.

[0072] Spray 2 adopts a shower plate in a downward spray mode (showerhead), and together with the gas circuit system, provides reactants for side-section passivation coating. The gas circuit system preferably includes: a first deposition gas pipeline, a second deposition gas pipeline, and a purge / supplement gas pipeline. The gas circuit system also preferably includes a temperature control and liquid replenishment 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 / supplement gas pipeline is composed of, for example, an MFC (gas flow controller), a pneumatic valve, a connecting pipeline, etc.

[0073] The reactants are preferably TMAl (trimethylaluminum) and H 2 O, but not limited thereto, according to the specific coating, it can also be other suitable reactants, such as triethylaluminum, ethylaluminum dichloride, diethylaluminum monochloride and other aluminum-containing metal organic substances, O 3 , H 2 O 2 , O after plasma ionization 2 O-containing gaseous substances. TMAl and H 2 O flows into the source bottle through centralized liquid supply and other means, and then flows into the source bottle as N 2 Or inert gas such as Ar as carrier gas, after the carrier gas is introduced into the source bottle, TMAl and H 2 O will be carried out according to the saturated vapor pressure and the principle of bubbling method and enter the reaction chamber 1. 2 O is the reactant, N 2 When it is a carrier gas, the passivation film formed is AlOx, but the passivation film is not limited to AlOx, and can also be other suitable substances such as poly-Si, SiOx, SiNx, etc.

[0074] like Figure 5 As shown, 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 required. 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, Figure 2 The lower surface (gas outlet surface) of the spray 2 shown in the figure is arranged opposite to the upper surface of the tray 4. The material of the tray 4 is preferably graphite, metal or the like, but is not limited thereto, and any other suitable material may be used according to actual conditions. A plurality of film boxes A may be placed on the tray 4. The spacing between the lower surface of the spray 2 and the upper surface of the tray 4 may be 1.0-50 cm, and the height of the film box A may be 0.2-30 cm, so the spacing between the upper end surface of the film box A and the gas outlet surface of the spray 2 may be 0.8-20 cm.

[0075] When coating the side cut surface, the sheet box A is used to place the cut battery cells whose side cut surfaces need to be passivated and protect the battery cells. For example, 10-2000 cut battery cells can be stacked in each sheet box A, preferably 200-600 cells. The battery cells in the sheet box A are as close to each other as possible without being damaged. Figure 6 As shown, a processing window is provided on the side of the wafer box A so that the side section of the solar cell is exposed to the passivation coating atmosphere for passivation during coating. The number of wafer boxes A is more than 2, preferably more than 4, more preferably more than 8, or any number according to actual needs.

[0076] The film box A can be placed in the reaction chamber at any angle and in any manner suitable for coating. There are many ways to place the film box A on the tray 4, such as facing the center of the tray, facing away from the center of the tray, rotating the windward side, rotating the leeward side, and the placement angle can be, for example, perpendicular to the plane of the tray.

[0077] The total number of cells in the cassette A placed on the tray 4 can reach several thousand, and the total weight of the tray 4, the cassette A and the cells can reach 100 kg or even higher. In this case, the rotating device 3 is equipped with a driving device sufficient to ensure rotation. Preferably, when the weight of the cassette A and the cells exceeds 10 kg, a fixing device capable of fixing the tray 4 to the rotating device is also included, and the fixing device is used to ensure stable rotation of the tray 4.

[0078] Heaters 5 are provided at the bottom and sides of the tray 4 to maintain the reaction temperature, and heating components are included inside the heaters 5. The heater 5 provided at the bottom and the heater 5 provided at the sides are preferably 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 components increases with increasing height. The heating component can be, for example, a resistance wire, or any other suitable component. Preferably, the temperature difference from the lower end surface to the upper end surface of the chip box A is within 5 degrees, and further preferably, as Figure 5 As shown, a heater 5 is also provided below the upper cover 6 to enhance uniform heating in the reaction chamber 1 , but the present invention is not limited thereto, and the heater 5 may not be provided below the upper cover 6 .

[0079] Preferably, a valve opening is provided on the side 7 of the reaction chamber 1, which is connected to a transmission system through the valve opening, and an operation is performed between the valve opening and the transmission system through a transmission mechanism, and the transmission system is, for example, a conveyor belt. The transmission mechanism is preferably a gripper, such as a cantilever gripper, which puts the cassette A containing unpassivated cells into the tray 4, and takes the cassette A containing passivated cells out of the tray 4. The cantilever gripper is adapted to the cassette A to achieve the required movement of the cassette A in the reaction chamber, and the movement includes but is not limited to lifting, putting down, or parallel movement of the cassette A.

[0080] In addition, an exhaust system 9 is provided to exhaust the gas generated during the passivation coating process. The exhaust system 9 is connected to a vacuum pump to ensure the vacuum degree of the cavity. The exhaust system 9 includes an exhaust device provided at the bottom 8 and an exhaust channel provided at the side 7. The exhaust device makes the airflow basically stable under the reaction conditions without dead airflow zones. Figure 5 The suction channel is shown to be at substantially the same height as the tray 4 .

[0081] like Figure 5 As shown, it also includes a plasma RF power supply 10 disposed between the spray 2 and the upper cover 6, which is used to generate plasma to assist in film coating. The plasma RF power supply 10 generates plasma after discharge, which can assist in film coating methods such as ALD. However, the plasma RF power supply 10 is not necessary, and the plasma RF power supply 10 may not be provided.

[0082] In addition, a power supply device is provided to supply power to the entire passivation coating equipment. The power supply device is preferably an electric cabinet, and may also be other suitable power supply devices.

[0083] like Figure 7 As shown, the specific process of the coating method involved in the third aspect of the present invention is that first, step S100 is performed to cut the battery cell. The cutting can be performed by laser cracking, but it 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 passivation area, 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 passivation area. 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 the 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 the multiple chip boxes are placed from the tray to the passivated area.

[0084] In addition, step S100 is not necessary, and the coating method can also be implemented by directly performing steps S101 to S105 on the cut battery cells without performing step S100.

[0085] Preferably, after step S100 and before step S101, a cleaning step is further performed to clean the cut cell. After cleaning, the contamination on the cell surface can be removed to obtain a cell surface that meets the cleanliness requirements, which is more conducive to reducing wrap-around plating during film coating.

[0086] Preferably, after step S105, an oxygen-free cooling step is also performed to cool the cell after the passivation film is formed to room temperature in an oxygen-free environment. The oxygen-free cooling means that the cell after the film coating is cooled from the deposition temperature to room temperature in an oxygen-free state, that is, it is not exposed to air. In this way, the oxygen in the air is prevented from oxidizing the metal grid lines on the cell at high temperature, thereby avoiding such oxidation from affecting the packaging of subsequent components.

[0087] Preferably, an annealing step is performed between step S104 and step S105, and an annealing process is performed at a temperature of 100-450°C.

[0088] Preferably, in step S104, the reaction temperature is 100-600° C., and the reaction pressure is 0-200 Torr, and more preferably, the reaction temperature is 100-300° C., and the reaction pressure is 0-100 Torr.

[0089] After the side cut surface is passivated and coated by the above coating method, the cut solar cell of the present invention is obtained. According to the test, the efficiency of the solar cell is greatly improved after the passivation coating by the process of the present invention. For example, the efficiency of a 144-piece module composed of 182mm*91mm silicon wafers is improved by 6W.

[0090] The coating method of the present invention is further described below based on embodiments.

[0091] (Example 1)

[0092] The device used in the coating method includes a circular reaction chamber 1, a spray 2 in an upper spray mode, a rotating device 3 including a rotating shaft and a motor, a tray 4 made of graphite, a heater 5 arranged at the bottom and side of the tray 4, and a gas path system. The circular reaction chamber 1 is composed of an upper cover 6, a side 7, and a bottom 8. No valve opening is provided on the side 7 of the circular reaction chamber 1. The heater 5 arranged at the bottom of the tray 4 and the heater 5 arranged at the side of the tray 4 are not integrated.

[0093] First, cut the printed and sintered cells in half, align the side cut surfaces and put them into 8 cell boxes, and stack them tightly without damaging the cells. Each cell box contains 10 cells, and the cell boxes containing the cells are placed in the area to be passivated. Then place the 8 cell boxes from the area to be passivated onto the tray 4 and place them in a Figure 8 The distance between the lower surface of the shower 2 and the upper surface of the tray 4 is 11 cm, the height of the film box is 10 cm, and the distance between the upper end surface of the film box and the lower surface of the shower 2 is 1 cm.

[0094] The reactants are TMAl (trimethylaluminum) and H 2 O, carrier gas is N 2 , enter the reaction chamber through the gas system. TMAl and H 2 O flows into the gas system through centralized liquid supply, and then N 2 After entering the gas system, TMAl and H 2 O will be carried out according to the saturated vapor pressure and the principle of bubbling method and enter the reaction chamber 1. TMAl and H 2 O to N 2 As carrier gas, after entering the reaction chamber 1, CVD reaction is carried out. The process reaction time is 5 minutes. The passivation film formed on the side section is Al 2 O 3 , with a thickness of 10nm. During the reaction, the reaction temperature was 200℃, N 2 The flow rate of TMAl is 500 sccm, N 2 H 2 The flow rate of O is 300 sccm, N 2 The flow rate of the purge gas is 5 slm, and the chamber pressure is 20 Torr.

[0095] After the side cut surface is passivated, all eight film boxes are placed from tray 4 into the passivated area.

[0096] After the side cut surface passivation coating is completed by the coating method of Example 1, the tested cell is as follows: Fig.10 As shown, there is almost no wrap-around plating, the front side is plating at 0.7mm, the back side is plating at 0.5mm, and the 72-piece component has no dark spots of EL.

[0097] (Example 2)

[0098] The device used in Example 2 is similar to the device in Example 1, except that a valve opening is provided on the side 7 of the circular reaction chamber 1, and is connected to the conveyor belt through the valve opening. The heater 5 provided at the bottom of the tray 4 and the heater 5 provided at the side of the tray 4 are integrated and provided with a fixing device.

[0099] First, stack the halved cells and put them into 12 cell boxes, tightly stacking them without damaging the cells. Each cell box contains 500 cells, and the cell boxes containing the 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. Fig. 9 The arrangement of 12 wafer boxes is shown in FIG. The spacing between the lower surface of the spray 2 and the upper surface of the tray 4 is 10.8 cm, the height of the wafer box is 10 cm, and the spacing between the upper end surface of the wafer box and the lower surface of the spray 2 is 0.8 cm. Through the valve opening, the cantilever gripper puts the wafer box containing the unpassivated battery cells from the passivation area into the tray 4, and takes the wafer box containing the passivated battery cells out of the tray 4. The cantilever gripper is adapted to the wafer box to move the wafer box, and can lift, put down, and move forward and backward.

[0100] The reactants are TMAl and H 2 O, carrier gas is N 2 , enter the reaction chamber through the gas system. TMAl and H 2 O flows into the gas system through centralized liquid supply, and then N 2 After entering the gas system, TMAl and H 2 O will be carried out according to the saturated vapor pressure and the principle of bubbling method and enter the reaction chamber 1. TMAl and H 2 O to N 2 As carrier gas, after entering the reaction chamber 1, CVD reaction is carried out. The reaction time is 20 minutes, and the passivation film formed is Al 2 O 3 , with a thickness of 50nm. During the reaction, the reaction temperature was 250℃ and the chamber pressure was 5Torr. 2 O 3 After deposition, annealing was performed for 30 min at a temperature of 300 °C.

[0101] After the coating of the side sections is completed, all 12 cassettes are placed from tray 4 into the passivated area.

[0102] After the side section is coated using the coating method of Example 2, the cell is Fig.10 As shown, there is almost no wrapping, the front side is wrapped at 0.5mm, and the back side is wrapped at 0.4mm. After passivation of the side section, the absolute efficiency of the 182mm×91mm cell is improved by 0.28%. The absolute value of the power of the 144-piece module (72 panels) composed of these cells is increased to 6W.

[0103] The following table shows the test results of an assembly of 144 182mm×91mm battery cells welded together. The unit of power is W, the unit of current is A, the unit of voltage is V, the unit of series resistance is Ω, and the fill factor represents the ratio of the maximum output power of the battery to the incident light power. In the following table, the control group refers to an assembly that has not been passivated as a control. The 50nmA group refers to an assembly of battery cells welded together using the method of the above-mentioned embodiment 2. The 30nmA group refers to an assembly of battery cells welded together using the method of the above-mentioned embodiment 4. The 50nmB group refers to an assembly of battery cells welded together using the coating method in the prior art for passivation of 50nm, and the wrap-around plating phenomenon is still very serious (the wrap-around plating width is above 3mm). The 30nmB group refers to an assembly of battery cells welded together using the coating method in the prior art for passivation of 30nm, and the wrap-around plating phenomenon is still very serious (the wrap-around plating width is above 3mm).

[0104]

[0105] As can be seen from the table above, the power of the battery cell welded assembly manufactured by the method of Example 2 of the present invention is significantly improved compared with the control group due to very little winding plating. In contrast, the coating method of the prior art has a very serious degree of winding plating, and the winding plating width is at least 3mm. Therefore, even if 50nm or 30nm of passivation is performed, the power is not improved at all compared with the control group, and even decreased.

[0106] It can be seen that according to the coating method of the present invention, the side-cut surface of the printed cell is repaired by coating to reduce wrap-around plating, which can repair the cutting loss of the cut cell, solve the technical problems of wrap-around plating on the cut cell and loss of cell efficiency caused by cutting the cell, improve the efficiency of the cell module, and reduce the cost of power generation of the module.

[0107] Although the embodiments of the present invention are described in detail above, it is obvious to those skilled in the art that various modifications and variations can be made to these embodiments. However, it should be understood that such modifications and variations are within the scope and spirit of the present invention as described in the claims. Moreover, the present invention described herein may have other embodiments and may be implemented or realized in a variety of ways.

Claims

1. A side-section passivation coating device for a cell, characterized in that: include: A reaction chamber for coating; Spray, located at the upper part of the reaction chamber; A rotating device is arranged at the bottom of the reaction chamber; A tray, arranged above the rotating device and opposite to the spray, for placing a plurality of cell boxes containing cut cell sheets; A heater, disposed on the bottom and sides of the tray and including heating elements therein; A gas system connected to the spray to provide reactants for coating; The exhaust system is used to ensure the vacuum degree of the reaction chamber and the stability of the reaction gas flow. The spray plate is in downward spray mode. The spray plate and gas system together provide the reactants for coating. The gas circuit system includes: a first sediment gas pipeline, a second sediment gas pipeline, and a purge / supplement gas pipeline. For the heater installed on the side, the heating intensity increases with the height from the bottom to the top. The side-cut passivation coating equipment of the battery cell is used to coat the side-cut of the battery cell after cutting.

2. The side-section passivation coating device of a cell according to claim 1, characterized in that: The first sediment gas pipeline and the second sediment gas pipeline are both composed of a gas flow controller, a source bottle, a pneumatic valve, a connecting pipeline, and a pressure controller.

3. The side-section passivation coating device of a cell according to claim 1, characterized in that: The gas circuit system also includes temperature control and fluid replenishment systems.

4. The side-section passivation coating device of a cell according to claim 1, characterized in that: The material of the tray is graphite or metal, and the number of the film boxes is greater than or equal to 2.

5. The side-section passivation coating device of a battery cell according to claim 1, characterized in that: The reaction chamber is a circular chamber and comprises an upper cover, a side portion and a bottom portion.

6. The side-section passivation coating device of a cell according to claim 5, characterized in that: A heater is also provided under the upper cover.

7. The side-section passivation coating device of a cell according to claim 5, characterized in that: A valve opening is arranged on the side of the reaction chamber, which is connected with the transmission system through the valve opening, and the transmission mechanism operates between the valve opening and the transmission system.

8. The side-section passivation coating device of a cell according to claim 7, characterized in that: The transmission mechanism is a gripper, which is matched with the film box to move the film box.

9. The side-section passivation coating device of a cell according to claim 1, characterized in that: Also includes a fixing device provided on the rotating device and the tray, The rotating device includes a rotating shaft and a motor.

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: Between step S100 and step S101, a cleaning step of the cut battery cells is also included.

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. The passivation coating method according to claim 10 or 11, characterized in that: Step S104 includes one or more plasma chemical vapor reaction steps.

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