Main-grid-free monocrystalline silicon solar cell interconnection method

Abstract

The invention relates to the technical field of solar cells, in particular to a main-grid-free monocrystalline silicon solar cell interconnection method, which comprises the following steps of: S1, arranging colloids on two surfaces of a cell piece; s2, a welding strip is laid above the glue body along the center line of the glue, and pressurization is carried out; s3, carrying out cross-linking reaction on the colloid; s4, heating the cross-linked battery piece until the welding strip coating is melted and forms an alloy with the battery grid line; and S5, cooling to obtain the product. The method has better mass production reliability, and due to the fact that the process route is simple and controllable, the method has high adaptability to different devices, and only one colloid is added to a process monitoring point for printing, the process debugging difficulty is greatly reduced.

Description

Technical Field

[0001] The invention relates to the technical field of solar cells, and in particular to a method for interconnecting main-grid-free monocrystalline silicon solar cells. Background Art

[0002] 0BB (Zero-Busbar) cell technology, as a cutting-edge innovation in the photovoltaic field, represents a major change in solar cell design. This technology completely abandons the main grid structure on the front of traditional solar cells and adopts a new and more sophisticated interconnection method to collect and conduct current. The development of 0BB technology is a further evolution of the existing Multi-Busbar (MBB) and Super Multi-Busbar (SMBB) technologies, aiming to significantly improve the photoelectric conversion efficiency and reduce the production cost by reducing the shading area and the use of metal electrodes.

[0003] In traditional photovoltaic cells, the main grid is responsible for collecting the current generated on the surface of the cell and delivering it to the connection points at the edge of the cell. However, these metal grids block part of the incident light, affecting the efficiency of the cell. By completely removing the main grid and retaining only the secondary grid, 0BB technology not only greatly reduces the shading area, but also significantly reduces the consumption of silver paste, which is one of the more expensive materials in cell manufacturing. At the component level, the original main grid function is replaced by thin welding ribbons or other innovative interconnection technologies that can more efficiently transfer current between cells while reducing power losses.

[0004] The realization of this technology relies on precise screen printing technology and advanced metallization process, as well as special designs adopted in the component packaging stage, such as the use of finer interconnects and optimized welding technology. PV companies such as Risen Energy have successfully applied 0BB technology in heterojunction (HJT) cells and TOPCon cells, achieving high efficiency of more than 25% and GW-level mass production, marking an important step for 0BB technology to move from the laboratory to commercialization.

[0005] However, in the 0BB production process, there are technical problems such as high consumption of silver paste of the solder strip and easy falling off. Summary of the invention

[0006] The purpose of the present invention is to provide a busbar-free monocrystalline silicon solar cell interconnection method to solve the technical problems of high silver paste consumption and easy falling off of the solder strip in the 0BB production process in the prior art.

[0007] The present invention discloses a method for interconnecting a main grid-free monocrystalline silicon solar cell, comprising the following steps:

[0008] S1. Set colloid on both sides of the battery cell;

[0009] S2. Lay the solder strip along the center line of the glue on top of the colloid and apply pressure;

[0010] S3. causing the colloid to undergo a cross-linking reaction;

[0011] S4. The cross-linked battery cell is heated until the solder coating melts and forms an alloy with the battery grid line;

[0012] S5. After cooling, the product is obtained.

[0013] Furthermore, the colloid in step S1 is printed on both sides of the busbar-free monocrystalline silicon solar cell by screen printing.

[0014] Furthermore, the screen printing screen opening size is 0.8*1mm, and the screen thickness is 150um.

[0015] Furthermore, the pressurized pressure in step S2 is greater than 2N.

[0016] Furthermore, in step S3, the colloid undergoes a cross-linking reaction by heating or ultraviolet irradiation.

[0017] Furthermore, in step S4, the heating temperature is 180-220 degrees Celsius, and the heating time is 4-7 seconds.

[0018] Furthermore, the cell is a PERC cell, a TOPCon cell, a HJT cell or an IBC cell.

[0019] Furthermore, the dimensions of the battery cell are: long side 166-230 mm, short side 90-110 mm, thickness 80-120 um, preferably long side 210, short side 105 mm, thickness 110 um.

[0020] Furthermore, the colloid is: an acrylate system, an epoxy resin system or a silicone system, preferably an acrylate system.

[0021] Furthermore, the colloid viscosity is 1000-30000 mPa·s, preferably 8000 mPa·s.

[0022] Furthermore, the base material of the welding strip includes: pure copper (>99%) or silver (>98%), preferably pure copper.

[0023] Furthermore, the welding strip is a low-temperature coated welding strip.

[0024] Furthermore, the coating composition includes: Sn, Pb, Bi or Ag.

[0025] Furthermore, the coating is Sn 43 Pb 43 Bi 14.

[0026] Furthermore, the size of the welding strip is: diameter 0.1-0.3 mm, preferably 0.22 mm, coating thickness 5-30 um, preferably 13 um.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] 1. Compared with the conventional busbar-free monocrystalline silicon solar cell processing method (only printing colloid and curing without welding), the process of curing by cross-linking reaction of colloid and then welding in this scheme brings better quality reliability; compared with the method of welding first and then fixing colloid, it has lower battery silver paste consumption; compared with the method of fixing with glue and then laminating alloy, it has higher process reliability and product reliability; it can adapt to a variety of busbar-free monocrystalline silicon solar cell grid line patterns, which can greatly reduce silver consumption;

[0029] 2. The present invention has better mass production reliability. Thanks to the simplicity and controllability of the process route, it has strong adaptability to different equipment, and the process monitoring point only adds one colloid printing, which greatly reduces the difficulty of process debugging;

[0030] 3. The battery cell of the present invention has extremely low silver consumption, the price of colloid is much lower than that of silver paste, and the overall cost is reduced by about 20%, which is conducive to large-scale production. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only represent some embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0032] Figure 1 This is a schematic diagram of the process for preparing a battery cell with colloid in Example 1.

[0033] Figure 2 This is a schematic diagram of the screen opening used in preparing a battery sheet with colloid in Example 1.

[0034] Figure 3 This is a schematic diagram of a battery string fixed by colloid prepared in Example 2.

[0035] Figure 4 Schematic diagram of the heating mechanism, battery string and press when the finished battery string is prepared in Example 3.

[0036] Figure 5 This is the electroluminescence image of the finished battery string prepared in Example 3.

[0037] Figure 6 This is the electroluminescent image of the finished battery string prepared in Example 4

[0038] Figure 7 This is a schematic diagram of the battery cell structure prepared by the present invention. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are clearly and completely described below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments.

[0040] The following embodiments are realized by using heterojunction solar cells, acrylate system UV curing glue, viscosity selected from 2000-8000mPa·s, welding strip diameter selected from 0.22mm, coating composition Sn4Pb43Bi14, coating thickness 10um, UV lamp power 1000mj / s, silk screen opening number 6 glue dots per thread, glue dot size 1*1.5mm, long side parallel to fine grid, heating welding, and the specific structure is as follows Figure 7 shown.

[0041] Example 1

[0042] This embodiment is used to illustrate the glue printing method of the present invention.

[0043] This embodiment discloses a busbar-free monocrystalline silicon solar cell interconnection method, comprising the following steps:

[0044] Place the monocrystalline silicon solar cell on the printing platform and move it to the bottom of the printing screen, with a spacing of about 250um. The specific placement method is as follows: Figure 1 As shown. The scraper on the screen is close to the screen. The glue is an acrylic ester system UV curing glue with a viscosity of 9000mPa·s and a glue amount of 10mg. The size of the screen glue point opening is 0.5*1mm, the screen thickness is 100um, and the reference screen is as follows Figure 2 The scraper angle is 75 degrees, the scraper speed is 500 mm / s, and after scraping along the short side of the cell, a single crystal silicon solar cell with a colloid height of 220 um is obtained.

[0045] Example 2

[0046] This example is used to illustrate the curing method of the present invention.

[0047] The monocrystalline silicon solar cell with colloid obtained in Example 1 is placed on the belt with a long side spacing of 0.8 mm. The upper and lower parts of the solar cell have pre-laid welding strips with a diameter of 0.22 mm and a coating composition of Sn. 43 Pb 43Bi 14 , coating thickness 13um. Use the jig to press the solder strip and the cell together, with a pressure of 2N / point, and use 8 points for fixation. Then use the conveyor belt to send the cell string pressed by the jig to the position with ultraviolet light source above and below, with the light intensity of 2000mj / s, and the light is on for 1s, so that the UV colloid is completely cured, and a single crystal silicon solar cell string with a solder strip series structure fixed by UV colloid is obtained. The final structure is as follows Figure 3 shown.

[0048] Example 3

[0049] This embodiment is used to illustrate the welding method of the present invention.

[0050] The monocrystalline silicon solar cell string with a solder ribbon series structure fixed by UV colloid obtained in Example 2 is placed on a heating platform, and the cell is pressed tightly on the platform by a press, and the pressure of the press is about 2N. Then the heating platform is heated to 180 degrees Celsius for 5 seconds, and then the cell string is removed by a suction cup for cooling, and the welding condition is observed by electroluminescence. The heating method is as follows Figure 4 The electroluminescence image obtained is shown in Figure 5 As shown, no cold solder joints or broken gates were found in the EL test, and the overall grayscale value was balanced, which was similar to the EL test results of conventional SMBB.

[0051] Example 4

[0052] Based on Example 3, only the printed glue is cured without welding. The electroluminescence test results are as follows Figure 6 As shown, there are obvious large-scale virtual connections in the electroluminescent image, and the grayscale values ​​are extremely unbalanced, which cannot be used as a basis for measurement standards.

[0053] The above are the implementation methods listed in this embodiment, but this embodiment is not limited to the above optional implementation methods. Those skilled in the art can arbitrarily combine the above methods to obtain other various implementation methods. Anyone can derive other various forms of implementation methods under the inspiration of this embodiment. The above specific implementation methods should not be understood as limiting the scope of protection of this embodiment. The scope of protection of this embodiment shall be based on the definition in the claims, and the description can be used to interpret the claims.

Claims

1. A method for interconnecting busbar-free monocrystalline silicon solar cells, characterized in that: The following steps are involved: S1. Set colloid on both sides of the battery cell; S2. Lay the solder strip along the center line of the glue on top of the colloid and apply pressure; S3. causing the colloid to undergo a cross-linking reaction; S4. The cross-linked battery cell is heated until the solder coating melts and forms an alloy with the battery grid line; S5. After cooling, the product is obtained.

2. A busbar-free monocrystalline silicon solar cell interconnection method according to claim 1, characterized in that: In the step S1, the colloid is printed on both sides of the busbar-free monocrystalline silicon solar cell by screen printing.

3. A busbar-free monocrystalline silicon solar cell interconnection method according to claim 1, characterized in that: The pressure applied in step S2 is greater than 2N.

4. A busbar-free monocrystalline silicon solar cell interconnection method according to claim 1, characterized in that: In step S4, the heating temperature is 180-220 degrees Celsius and the heating time is 4-7 seconds.

5. The method for interconnecting busbar-free monocrystalline silicon solar cells according to claim 1, characterized in that: The battery cell is: a PERC battery, a TOPCon battery, a HJT battery or an IBC battery.

6. A busbar-less monocrystalline silicon solar cell interconnection method according to claim 1, characterized in that: The colloid is: an acrylate system, an epoxy resin system or a silicone system, preferably an acrylate system.

7. The method for interconnecting busbar-free monocrystalline silicon solar cells according to claim 1, characterized in that: The welding strip is a low-temperature coated welding strip.

8. A busbar-less monocrystalline silicon solar cell interconnection method according to claim 7, characterized in that: The coating composition is: Sn, Pb, Bi or Ag.

9. A busbar-less monocrystalline silicon solar cell interconnection method according to claim 8, characterized in that: The coating is Sn 43 Pb 43 Bi 14 .

10. The method for interconnecting busbar-free monocrystalline silicon solar cells according to claim 1, characterized in that: The size of the welding strip is: diameter 0.1-0.3mm, preferably 0.22mm, coating thickness 5-30um, preferably 13um.

Images