A patterned carrier film prepared gridless assembly and method of making the same

Abstract

This invention discloses a gridless module fabricated using a patterned carrier film. The gridless module structure, from the light-receiving surface to the outer surface, consists of transparent glass, an upper adhesive film, an upper patterned carrier film, an OBB (On-Board Battery) string, a lower patterned carrier film, another lower adhesive film, and a backsheet. The OBB string comprises multiple arrayed gridless cells. Adjacent cells in the OBB string are connected in parallel by several sets of low-temperature solder ribbons. The upper and lower patterned carrier films are patterned by laser cutting or an automatic cutter, and the resulting pattern is pasted and fixed to the front and back of the OBB string in a "grid" shape. The patterned carrier film is used to wrap and fix the low-temperature solder ribbons to the front and back of the string using infrared low-temperature thermal welding, strengthening the connection between the solder ribbons and the cells, preventing delamination in fully coated states, and improving the reliability of the module.

Description

Technical Field

[0001] This invention relates to the field of solar photovoltaic technology, and in particular to a gridless module with a patterned carrier film and its preparation method. Background Technology

[0002] As the efficiency of silicon-based solar cells has reached a bottleneck, cost reduction has become a long-term goal for major companies. Typically, photovoltaic cells use silver paste for the main grid, which is expensive. Therefore, reducing silver paste consumption is crucial. Based on the need to reduce the absolute amount of silver paste used and to find alternatives, more and more researchers are focusing on the development of gridless cells. Gridless cells eliminate the need for traditional main grid silver paste, using solder ribbons to collect fine grid current and achieve cell interconnection. Current technologies typically use dispensing or lamination methods. However, lamination usually involves covering the entire mask material onto the cell and then fixing it through other processes. This process can prevent good contact between the cell and the film, leading to significant cell string misalignment during lamination and the risk of parallel / serialization. It also negatively impacts subsequent reliability verification.

[0003] To address this, the applicant has patterned the mask material to expose portions of the solar cells, ensuring complete contact with the adhesive film. This resolves the risk of battery string misalignment and parallel connection during lamination, thereby improving the reliability verification of the module. Summary of the Invention

[0004] To address the aforementioned issues, this invention provides a gridless module fabricated using a patterned carrier film to reinforce the connection between the solder ribbon and the battery cell, thereby preventing delamination in the fully coated state and improving the reliability verification of the module.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a gridless assembly made of a patterned carrier film, wherein the gridless assembly structure, from the light-receiving surface to the outer surface, consists of transparent glass, an upper adhesive film, an upper patterned carrier film, an OBB battery string, a lower patterned carrier film, a lower adhesive film, and a backplate. The OBB battery string is composed of multiple arrayed gridless battery cells. Adjacent battery cells in the OBB battery string are connected in parallel by several sets of low-temperature solder ribbons. The two ends of the low-temperature solder ribbons are respectively connected to the light-receiving surface of one battery cell and the backlight surface of the next battery cell. The low-temperature solder ribbons at both ends of the OBB battery string extend outward. The upper and lower patterned carrier films are patterned by laser cutting or automatic cutting to cut the block-shaped carrier film into a "well" shape. The upper and lower patterned carrier films are pasted and fixed to the front and back of the OBB battery string.

[0006] Furthermore, both the upper patterned carrier film and the lower patterned carrier film are composed of a light absorption layer, an ultraviolet light conversion layer, and an adhesive layer formed by multi-layer co-extrusion.

[0007] Furthermore, the thickness of the upper patterned carrier film and the lower patterned carrier film is set to 0.05-0.5 mm.

[0008] Furthermore, the overall length and width of the upper patterned carrier film and the lower patterned carrier film are both less than or equal to the length and width of half a battery cell. The width of the horizontal lines is set to 1-6mm, the number of horizontal lines is set according to the number of solder strips on a single battery cell, and the length is set to be less than or equal to the width of half a battery cell. The number of vertical lines is between 2 and 6, the width is set to 5-30mm, and the length is set to be less than or equal to the length of half a battery cell.

[0009] Furthermore, the OBB battery string uses thickened and widened sub-grid lines in the welding ribbon area, or thinned main grid lines to the same width as the thin grid lines, so that the low-temperature welding ribbon is welded to the battery cell, and the welding ribbon coating on the low-temperature welding ribbon is alloyed with the sub-grid lines of the battery cell.

[0010] Furthermore, the diameter of the low-temperature welding strip is set between 0.15mm and 0.35mm.

[0011] A method for fabricating a gridless module using a patterned carrier film is disclosed. The method involves first cutting a block-shaped carrier film into a patterned shape using laser cutting or an automatic cutter, resulting in a "grid" pattern. Then, the patterned carrier film is wrapped with low-temperature solder ribbons using infrared low-temperature thermal welding and adhered to the front and back of an OBB battery string. The patterned carrier film is then attached to both the top and bottom of the OBB battery string on a coating platform. The coated OBB battery string and pressing fixture are then transported to an infrared heating zone. The heating temperature is controlled at approximately 120°C, causing the patterned carrier film to shrink and melt, bonding it to the OBB battery string. Finally, from the light-receiving surface to the outer surface, the following layers are laminated in a laminator: transparent glass, upper adhesive film, upper patterned carrier film, OBB battery string, lower patterned carrier film, lower adhesive film, and backplate.

[0012] Furthermore, the patterned carrier film is composed of bio-based resin, polyethylene, ethylene-vinyl acetate copolymer, and terpene resin.

[0013] Furthermore, the low-temperature solder strip coating is made of any one or more combinations of tin-lead-bismuth, tin-lead-bismuth-silver, tin-bismuth-silver, and tin-lead materials, with a melting point below 150°C.

[0014] As can be seen from the above description of the structure of the present invention, compared with the prior art, the present invention has the following advantages:

[0015] 1. The low-temperature thin solder ribbon is wrapped and fixed on the front and back of the battery string by the patterned carrier film through infrared low-temperature thermal welding, which can effectively reinforce the connection between the solder ribbon and the battery sheet, protect the solder ribbon and the battery sheet from alloying, make the current of the connected battery string flow well, and also isolate the contact between the solder ribbon and the adhesive film, prevent the adhesive film from penetrating into the solder ribbon and the battery sheet in the molten state, and directly cause the phenomenon of filling decline.

[0016] 2. The patterned carrier film can make most of the battery sheet contact with the adhesive film well through the corresponding cutout, prevent the battery string from shifting due to the melting and flowing of the adhesive film during lamination, avoid the delamination phenomenon after lamination in the full film state, and further improve the reliability verification of the assembly. At the same time, the transmittance of incident light to the battery will decrease to a certain extent, and the light transmittance will be higher than that of the full film. BRIEF DESCRIPTION OF DRAWINGS

[0017] The accompanying drawings, which form a part of this application, are included to provide a further understanding of the application, and are incorporated in and constitute a part of this application. The embodiments of the application illustrated in the drawings, and their description, are presented to explain the application and are not intended to limit the application. In the drawings:

[0018] Figure 1 A cross-sectional view of a no-tab assembly prepared by a patterned carrier film of the present application;

[0019] Figure 2 A structure diagram of the OBB battery string covered by the upper patterned carrier film of the present application. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical scheme and advantages of the present application clearer, the present application will be further described in detail below in combination with the drawings and examples. It should be understood that the specific examples described herein are only used to explain the present application and do not limit the present application.

[0021] EMBODIMENT

[0022] REFERENCE Figure 1 、 Figure 2A gridless assembly fabricated using a patterned carrier film is disclosed. The gridless assembly structure, from the light-receiving surface to the outer surface, consists of a transparent glass 4, an upper adhesive film 3, an upper patterned carrier film 2, an OBB battery string 1, a lower patterned carrier film 5, a lower adhesive film 6, and a backplate 7. The OBB battery string 1 is composed of multiple arrayed gridless battery cells. Adjacent battery cells in the OBB battery string are connected in parallel by several sets of low-temperature solder strips 8. The battery cells are 182 mm long and 91 mm wide. The two ends of each low-temperature solder strip 8 are connected to the light-receiving surface of one battery cell and the next... The backlight of the battery cell is connected, and the low-temperature solder strips 8 at both ends of the OBB battery string 1 are led outward. The upper patterned carrier film 2 and the lower patterned carrier film 5 are patterned by laser cutting or automatic cutting. The cut pattern is in the shape of a "well" with 20 strips, each 88mm long, 3mm wide, and 8.65mm apart. There are 2 vertical lines, each 180mm long, 15mm wide, and 30.3mm apart. The upper patterned carrier film 2 and the lower patterned carrier film 5 are pasted and fixed to the front and back of the OBB battery string 1.

[0023] Both the upper patterned carrier film 2 and the lower patterned carrier film 5 are composed of a light absorption layer, an ultraviolet light conversion layer and an adhesive layer formed by multi-layer co-extrusion, and the film thickness of the upper patterned carrier film 2 and the lower patterned carrier film 5 is set to 0.2 mm.

[0024] The OBB battery string 1 uses thickened and widened sub-grid lines in the welding ribbon area, or thinned main grid lines with the same width as the thin grid lines, so that the low-temperature welding ribbon is welded to the battery cell. The welding ribbon coating on the low-temperature welding ribbon 8 forms an alloy with the sub-grid lines of the battery cell. The diameter of the low-temperature welding ribbon 8 is set at 0.25mm.

[0025] The method for preparing the gridless component using the patterned carrier film is as follows: First, the patterned carrier film is patterned by laser cutting or an automatic cutter, resulting in a "well" shaped pattern. Then, the patterned carrier film is wrapped with low-temperature welding tape and fixed to the front and back of the OBB battery string using infrared low-temperature thermal welding. The patterned carrier film is then attached to both the top and bottom of the OBB battery string on a coating platform. The coated OBB battery string and the pressing fixture are then transported to the infrared heating zone. By controlling the heating temperature at around 120°C, the patterned carrier film shrinks and melts upon heating, bonding it to the OBB battery string. Finally, from the light-receiving surface to the outer surface, the following layers are arranged in sequence: transparent glass, upper adhesive film, upper patterned carrier film, OBB battery string, lower patterned carrier film, lower adhesive film, and backplate. These layers are then laminated in a laminator to form the final product.

[0026] The patterned carrier film is composed of bio-based resin, polyethylene, ethylene-vinyl acetate copolymer, and terpene resin.

[0027] The low-temperature solder strip coating is made of any one or a combination of tin-lead-bismuth, tin-lead-bismuth-silver, tin-bismuth-silver, and tin-lead, and has a melting point below 150 DEG C.

[0028] The low-temperature fine solder strip is wrapped and fixed on the front and back of the battery string by the patterned bearing film through infrared low-temperature thermal welding, which can effectively reinforce the connection between the solder strip and the battery sheet, protect the solder strip and the battery sheet from alloying, make the current of the connected battery string flow well, and isolate the contact between the solder strip and the adhesive film to prevent the adhesive film from penetrating into the solder strip and the battery sheet in the molten state to directly cause the phenomenon of filling reduction. The patterned bearing film is cut at the corresponding position, so that most of the battery sheet can be in good contact with the adhesive film, preventing the battery string from being displaced due to the melting and flowing of the adhesive film during the lamination process, avoiding the delamination phenomenon after lamination in the full film state, and further improving the reliability verification of the assembly. Meanwhile, the transmittance of incident light to the battery will decrease to some extent, and the light transmittance will be higher than that of the full film.

[0029] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Any modification, equivalent replacement, and improvement within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A gridless assembly fabricated from a patterned carrier film, characterized in that: The structure of the gridless assembly, from the light-receiving surface to the outer surface, consists of transparent glass, an upper adhesive film, an upper patterned carrier film, an OBB battery string, a lower patterned carrier film, a lower adhesive film, and a backplate. The OBB battery string is composed of multiple arrayed gridless battery cells. Adjacent cells in the OBB battery string are connected in parallel by several sets of low-temperature solder ribbons. The two ends of each low-temperature solder ribbon are connected to the light-receiving surface of one battery cell and the backlight surface of the next battery cell, respectively. The low-temperature solder ribbons at both ends of the OBB battery string extend outwards. The upper and lower patterned carrier films are patterned by laser cutting or an automatic cutter. After cutting... The pattern is in the shape of a "well" shaped grid. The upper and lower patterned carrier films are adhered and fixed to the front and back of the OBB battery string. Both the upper and lower patterned carrier films are composed of a light absorption layer, an ultraviolet light conversion layer, and an adhesive layer formed by multi-layer co-extrusion. The overall length and width of the upper and lower patterned carrier films are less than or equal to the length and width of half a battery cell. The width of the horizontal lines is set to 1-6mm, and the number of horizontal lines is set according to the number of solder strips on a single battery cell. The length is set to be less than or equal to the width of half a battery cell. The number of vertical lines is between 2 and 6, the width is set to 5-30mm, and the length is set to be less than or equal to the length of half a battery cell.

2. The gridless assembly fabricated from a patterned carrier film according to claim 1, characterized in that: The thickness of the upper and lower patterned carrier films is set to 0.05-0.5 mm.

3. The gridless assembly fabricated from a patterned carrier film according to claim 1, characterized in that: The OBB battery string uses thickened and widened sub-grid lines in the welding ribbon area, or thinned main grid lines with the same width as the thin grid lines, so that the low-temperature welding ribbon is welded to the battery cell, and the welding ribbon coating on the low-temperature welding ribbon is alloyed with the sub-grid lines of the battery cell.

4. The gridless assembly fabricated from a patterned carrier film according to claim 1, characterized in that: The diameter of the low-temperature welding strip is set between 0.15mm and 0.35mm.

5. A method for fabricating the gateless assembly according to claim 1, characterized in that: The method involves first cutting a block-shaped carrier film into a pattern using laser cutting or an automatic cutter, resulting in a "well" shape. Then, the patterned carrier film is wrapped with low-temperature welding tape using infrared low-temperature hot welding and fixed to the front and back of the OBB battery string. On a laminating platform, the patterned carrier film is attached to both the top and bottom of the OBB battery string. The laminated OBB battery string and pressing fixture are then transported to an infrared heating zone. By controlling the heating temperature at approximately 120°C, the patterned carrier film shrinks and melts upon heating, bonding it to the OBB battery string. Finally, from the light-receiving surface to the outer surface, the following layers are laminated in a laminator: transparent glass, upper adhesive film, upper patterned carrier film, OBB battery string, lower patterned carrier film, lower adhesive film, and backplate.

6. The method for fabricating a gridless assembly according to claim 5, characterized in that: The patterned carrier film is composed of bio-based resin, polyethylene, ethylene-vinyl acetate copolymer, and terpene resin.

7. The method for fabricating a gridless assembly according to claim 5, characterized in that: The low-temperature solder strip is made of any one or more of the following materials: tin-lead-bismuth, tin-lead-bismuth-silver, tin-bismuth-silver, and tin-lead, with a melting point below 150°C.

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