Back contact solar cell interconnection structure
By using interconnect film and low-temperature stringing process of solar cells, the problems of long cycle time and high equipment failure rate in back contact solar cell interconnection technology have been solved, achieving efficient cell connection and low repair rate.
Patent Information
- Application Number
- CN202520164594.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-24
- Publication Date
- 2026-02-17
- Estimated Expiration
- 2035-01-24
AI Technical Summary
Existing back-contact solar cell interconnection technology suffers from problems such as long cycle time, high equipment failure rate, low string bonding yield, and high string repair rate.
The interconnect film is manufactured into finished products and then adhered to the solar cells through a low-temperature stringing process to form a solar cell string. The interconnect film consists of a substrate film and interconnect strips. The interconnect strips match the electrode pattern on the back of the solar cell and are embedded or protruding from the surface of the substrate film. The adhesion of the substrate film is used to connect the solar cells.
It significantly reduced cycle time, increased production capacity, reduced defects such as microcracks and scratches in battery cells, and lowered the battery string repair rate.
Smart Images
Figure CN223928709U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of solar cells, and in particular to a back-contact solar cell interconnection structure. Background Technology
[0002] In existing technologies, the mainstream interconnection methods for back-contact solar cells include two main approaches: One is the traditional infrared thermal welding method: the back-contact solar cells and interconnecting strips are laid flat on the conveyor belt of a stringer, and the interconnecting strips are welded to the cells using infrared welding to form a cell string. The other approach uses a film coating: the back-contact solar cells are laid flat on the conveyor belt of the stringer with their backs facing up. Interconnecting strips are pulled and cut and placed on top of the back of the back-contact solar cells. A pre-cut film is then placed over the solar cells and interconnecting strips. After preheating to approximately 100°C, the film initially adheres to the back of the solar cells, fixing the interconnecting strips to the back of the back-contact solar cells to form a cell string.
[0003] While existing technologies can complete the stringing of solar cells, the process requires cutting the interconnecting strips every time a solar cell is placed, resulting in long cycle times, reduced production capacity, high equipment failure rate, low stringing yield, and high rework rate. Utility Model Content
[0004] The purpose of this invention is to provide a back-contact solar cell interconnection structure that uses pre-made interconnect films for welding. This not only greatly reduces cycle time and increases production capacity, but also reduces defects such as microcracks and scratches in the cells, thus lowering the cell string repair rate.
[0005] To achieve the above objectives, the present invention adopts the following technical solution:
[0006] This utility model discloses a back-contact solar cell interconnection structure, which includes a plurality of solar cells and an interconnecting film for connecting the plurality of solar cells into a cell string; the interconnecting film is composed of a substrate film and interconnecting strips; the interconnecting strips are matched with the electrode patterns on the back of the solar cells; part of the interconnecting strips is embedded in the substrate film, and part of the interconnecting strips protrudes from the surface of the substrate film; the substrate film of the interconnecting film adheres to the back area of the solar cells, and the protruding interconnecting strips of the interconnecting film contact the electrodes on the back of the solar cells, thereby connecting the solar cells into a cell string.
[0007] Furthermore, the basis weight of the substrate film is 50 g / m³. 2 ~150g / m 2 .
[0008] Furthermore, the interconnecting strip is a round wire interconnecting strip or a flat interconnecting strip.
[0009] Furthermore, the non-interconnecting strip area of the interconnecting film is uniformly distributed with a number of adsorption pores.
[0010] The advantages of this utility model are:
[0011] Compared with existing technologies, this invention allows for the online or offline fabrication of the interconnecting film, eliminating the need for alternating operations of battery cells and interconnecting strips, thus significantly reducing cycle time and increasing production capacity. Because the entire process utilizes a low-temperature stringing process, it offers advantages over conventional infrared welding processes, including lower stress and less warping, reducing defects such as microcracks and scratches in the battery cells and lowering the battery string rework rate. Attached Figure Description
[0012] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this utility model and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.
[0013] Figure 1 This is a schematic diagram of the interconnecting film and battery string of this utility model.
[0014] Figure 2 This is an exploded view of the battery string of this utility model.
[0015] Figure 3 This is a schematic diagram of the battery string welding process in Example 1.
[0016] Figure 4 This is a schematic diagram of the battery string welding process in Example 2.
[0017] Explanation of key component symbols:
[0018] 1. Battery cells;
[0019] 2. Interconnect film; 21. Substrate adhesive film; 22. Interconnect strip;
[0020] 3. Conveyor belt;
[0021] 4. Battery string. Detailed Implementation
[0022] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.
[0023] In this utility model, unless otherwise stated, directional terms such as "up," "down," "left," and "right" are generally understood in conjunction with the accompanying drawings and the directions shown in actual applications.
[0024] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.
[0025] In this utility model, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.
[0026] The endpoints and any values of the ranges disclosed herein are not limited to the precise ranges or values, and should be understood to include values close to these ranges or values. For numerical ranges, the endpoint values of the various ranges, the endpoint values of the various ranges and individual point values, and individual point values can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein. The terms "optional" and "discretionary" mean that they may or may not be included (or may or may not be present).
[0027] Example 1:
[0028] like Figure 1 , Figure 2 As shown, this embodiment discloses a back-contact solar cell interconnection structure, which includes a plurality of solar cells 1 and an interconnection film 2 that connects the plurality of solar cells 1 into a solar cell string 4.
[0029] The interconnecting film 2 consists of a substrate adhesive film 21 and interconnecting strips 22. The length and width of the interconnecting film 2 are designed based on the length and width of the battery string 4, plus a reserved dimension. The interconnecting film 2 has a front and a back side. The front side of the interconnecting film 2 is embedded with interconnecting strips 22 designed according to the battery electrode series structure. Part of the interconnecting strips 22 is embedded in the adhesive film, while another part protrudes from the adhesive film surface. The back side of the interconnecting film 2 has a flat adhesive film surface. The interconnecting strips 22 match the electrode pattern on the back side of the battery cell 1. The substrate adhesive film of the interconnecting film 2 adheres to the back side area of the battery cell 1, and the protruding interconnecting strips 22 of the interconnecting film 2 contact the electrodes on the back side of the battery cell 1, connecting the battery cells 1 into the battery string 4.
[0030] The basis weight of the substrate film 21 is 50 g / m². 2 ~150g / m 2 .
[0031] The interconnecting strip 22 is either a round wire interconnecting strip 22 or a flat interconnecting strip 22.
[0032] like Figure 3 As shown, the fabrication process of the back-contact solar cell interconnect structure in this embodiment includes the following steps:
[0033] S1. Fabrication of interconnect film 2: The interconnect strip 22 is cut to a size that matches the back contact heterojunction solar cell electrode pattern and can connect the cells 1 in series. The interconnect strip 22 is embedded into the surface of the substrate film 21 using a preheating and pressing process. The embedded side is the front side of the interconnect film 2. Part of the interconnect strip 22 is embedded in the substrate film 21, and part of it protrudes from the surface of the substrate film 21.
[0034] S2. Interconnecting film 2 and battery cell 1 are wired together: The back-contact solar cells 1 are neatly laid out on the conveyor belt 3 with their backs facing up according to the direction of the series structure. The placement spacing of the battery cells 1 is set according to the design requirements of the battery string 4. The interconnecting film 2 is placed on top of the battery cells 1 with its front facing down. The conveyor belt 3 has an adsorption and fixing function, which adsorbs the battery cells 1 and transports them directly below the interconnecting film 2. The stacking mechanism moves the interconnecting film 2 down and stacks the interconnecting strips 22 on the interconnecting film 2 with the electrodes on the back of the battery cells 1 placed on the conveyor belt 3, so that the interconnecting strips 22 are in direct contact with the back electrodes of the back-contact solar cells 1. The adsorption component on the conveyor belt 3 vacuum adsorbs and fixes the interconnecting film 2 on the conveyor belt 3 through the spacing between adjacent battery cells 1. The stacked solar cell 1 and interconnect film 2 are then transferred to the heating zone for preheating. The temperature of the heating zone is set to 80℃~130℃ and the effective heating time is 2S~10S. The substrate film 21 on the interconnect film 2 softens and adheres to the solar cell 1. The interconnect strip 22 is sandwiched between the substrate film 21 and the back contact solar cell 1 to form an interconnect structure.
[0035] The interconnecting membrane 2 can be fabricated in advance or simultaneously with step S2.
[0036] Compared to existing technologies, conventional back-contact solar cell interconnection methods involve alternating operations of a single cell and a set of interconnecting strips 22, followed by infrared welding to form a cell string 4. This results in long cycle times and a high breakage rate. In this embodiment, an integrated interconnecting film 2 is fabricated online or offline, eliminating the need for alternating operations of the cell 1 and interconnecting strips 22, significantly reducing cycle time and increasing production capacity. The arrangement and dimensions of the interconnecting strips 22 on the interconnecting film 2 are designed based on the electrode arrangement of the cell 1 and the desired length of the cell string 4. Low-temperature preheating is used for stringing, resulting in a gentle stringing process and a low breakage rate.
[0037] Example 2:
[0038] A number of adsorption pores are uniformly distributed on the interconnect film 2 in the non-interconnect strip 22 region. Other features are consistent with those in Example 1.
[0039] The main function of the adsorption holes is that when the interconnecting film 2 is placed on the conveyor belt 3 and the battery cell 1 is stacked on the interconnecting film 2, the adsorption components on the conveyor belt 3 can adsorb the battery cell 1 onto the conveyor belt 3 through the adsorption holes, so that the interconnecting film 2 and the battery cell 1 are tightly attached.
[0040] like Figure 4 As shown, the fabrication process of the back-contact solar cell interconnect structure in this embodiment includes the following steps:
[0041] S1. Fabrication of interconnect film 2: The interconnect strip 22 is cut to a size that matches the back contact heterojunction solar cell electrode pattern and can connect the cells 1 in series. The interconnect strip 22 is embedded into the surface of the substrate film 21 using a preheating and pressing process. The embedded side is the front side of the interconnect film 2. Part of the interconnect strip 22 is embedded in the substrate film 21, and part of it protrudes from the surface of the substrate film 21; (consistent with Example 1).
[0042] S2. String bonding of interconnect film 2 and solar cell 1: The interconnect film 2 is laid flat on conveyor belt 3 with its front side facing up and vacuum-adsorbed. The back-contact solar cell 1 is placed on top of the interconnect film 2 with its back side facing down. Conveyor belt 3 transports the interconnect film 2 directly below the solar cell 1. The stacking mechanism moves the solar cell 1 down so that its back electrode corresponds one-to-one with the interconnect strips 22 on the interconnect film 2, allowing the interconnect strips 22 to directly contact the back electrode of the back-contact solar cell 1. The adsorption component on conveyor belt 3 vacuum-adsorbs and fixes the solar cell 1 onto the conveyor belt 3 through several adsorption holes provided on the interconnect film 2. The stacked solar cell 1 and interconnect film 2 are then conveyed to a heating area for preheating. The heating area temperature is set to 80℃~130℃, and the effective heating time is 2S~10S. The substrate adhesive film 21 on the interconnect film 2 softens and adheres to the solar cell 1. The interconnect strips 22 are sandwiched between the substrate adhesive film 21 and the back-contact solar cell 1 to form an interconnect structure.
[0043] The interconnecting membrane 2 can be fabricated in advance or simultaneously with step S2.
[0044] In summary, this utility model uses interconnecting film 2 for welding, which can not only greatly reduce cycle time and increase production capacity, but also reduce defects such as microcracks and scratches on battery cells 1 and reduce the rework rate of battery string 4.
[0045] The preferred embodiments of this utility model have been described in detail above; however, this utility model is not limited thereto. Within the scope of the technical concept of this utility model, various simple modifications can be made to the technical solution of this utility model, including combining the various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed by this utility model and are all within the protection scope of this utility model.
Claims
1. A back contact solar cell interconnection structure, characterized by: The application relates to a battery interconnecting film (2) which comprises a plurality of battery pieces (1) and a plurality of interconnecting films (2) connecting the battery pieces (1) into a battery string (4); the interconnecting film (2) is composed of a base adhesive film (21) and an interconnecting strip (22); the interconnecting strip (22) is matched with the electrode pattern on the back of the battery piece (1); a part of the interconnecting strip (22) is embedded into the base adhesive film (21) and a part of the interconnecting strip (22) protrudes from the surface of the base adhesive film (21); the base adhesive film of the interconnecting film (2) is adhered to the back area of the battery piece (1), the protruding interconnecting strip (22) of the interconnecting film (2) is in contact with the electrode on the back of the battery piece (1), and the battery piece (1) is connected into the battery string (4).
2. The back contact solar cell interconnection structure of claim 1, wherein: The base adhesive film (21) has a grammage of 50 g / m 2 ~ 150 g / m 2 .
3. The back contact solar cell interconnection structure of claim 1, wherein: The interconnecting strip (22) is a round interconnecting strip (22) or a flat interconnecting strip (22).
4. The back contact solar cell interconnection structure of claim 1, wherein: A plurality of adsorption holes are uniformly distributed in the non-interconnecting strip (22) area of the interconnecting film (2).