Back contact solar cell interconnection structure and manufacturing process method thereof

Abstract

The invention relates to the field of solar cells, and discloses a back contact solar cell interconnection structure and a manufacturing process method thereof, and the back contact solar cell interconnection structure comprises a plurality of cell pieces and an interconnection film which connects the plurality of cell pieces into a cell string. The interconnection film is composed of a matrix adhesive film and an interconnection strip. And the interconnecting strips are matched with electrode patterns on the back surfaces of the battery pieces. One part of the interconnector is embedded into the matrix adhesive film, and the other part of the interconnector protrudes out of the surface of the matrix adhesive film. The basic adhesive film of the interconnection film is adhered to the back areas of the battery pieces, and the protruding interconnection strips of the interconnection film are in contact with the electrodes on the back surfaces of the battery pieces, so that the battery pieces are connected into a battery string. The manufacturing process method comprises the steps that S1, the interconnection film is manufactured, S2, the interconnection film and the battery piece are welded in series, and the interconnection film can be manufactured in advance or can be manufactured at the same time with the step S2. The interconnection film is adopted for welding, so that the beat time can be greatly shortened, the productivity can be improved, the defects of subfissure, scratch and the like of the battery piece can be reduced, and the repair rate of the battery string is reduced.

Description

Technical Field

[0001] The invention relates to the field of solar cells, in particular to a back contact solar cell interconnection structure and a manufacturing process method thereof. Background Art

[0002] The mainstream back-contact solar cell interconnection method in the prior art is the traditional infrared heat welding method: the back-contact solar cell and the interconnection strip are laid flat on the conveyor belt of the stringing machine, and the interconnection strip and the battery are welded together by infrared welding to form a battery string. The other is a coating solution: the back-contact battery cell is laid flat on the conveyor belt of the stringing machine with the back side facing up, and the cut interconnection strip is pulled and placed on the back of the back-contact battery cell, and then the cut skin film is covered on the battery cell and the interconnection strip. After preheating at about 100°C, the skin film is initially adhered to the back of the battery cell, and the interconnection strip is fixed on the back of the back-contact solar cell to form a battery string.

[0003] Although the existing technical solution can complete the string welding of battery cells, when placing a battery cell during the string welding process, the interconnection strip needs to be cut once, and the operation is performed alternately, the cycle time is long, which affects the production capacity. In addition, the equipment failure rate is high, the string welding yield is low, and the string repair rate is high. Summary of the invention

[0004] The purpose of the present invention is to provide a back-contact solar cell interconnection structure and a manufacturing process method thereof. The use of interconnection film for welding can not only greatly reduce the cycle time and improve production capacity, but also reduce defects such as hidden cracks and scratches on the battery cells and reduce the rework rate of the battery string.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] The invention discloses a back-contact solar cell interconnection structure, which comprises a plurality of solar cells and an interconnection film for connecting the plurality of solar cells into a solar cell string; the interconnection film is composed of a base adhesive film and an interconnection strip; the interconnection strip matches the electrode pattern on the back of the solar cell; a part of the interconnection strip is embedded in the base adhesive film, and a part protrudes from the surface of the base adhesive film; the base adhesive film of the interconnection film is adhered to the back area of ​​the solar cell, and the interconnection strip protruding from the interconnection film contacts the electrode on the back of the solar cell, so as to connect the solar cells into a solar cell string.

[0007] Furthermore, the base film has a gram weight of 50 g / m 2 ~150g / m 2 .

[0008] Furthermore, the interconnection strip is a round wire interconnection strip or a flat interconnection strip.

[0009] Furthermore, a plurality of adsorption holes are evenly distributed in the non-interconnection strip area on the interconnection film.

[0010] The present invention also discloses a method for manufacturing the above-mentioned back contact solar cell interconnection structure, which comprises the following steps:

[0011] S1. Making interconnection film: cutting the interconnection strip into a size that matches the electrode pattern of the back contact heterojunction solar cell and can connect the solar cells in series, and embedding the interconnection strip into the surface of the base film by preheating and pressing, with the embedded side being the front side of the interconnection film, with a part of the interconnection strip embedded in the base film and a part protruding from the surface of the base film;

[0012] S2. Serial welding of interconnection film and battery cell: stack the front side of the interconnection film and the back side of the back-contact solar cell together so that the interconnection strip on the interconnection film is in direct contact with the back electrode of the back-contact solar cell and fixed by vacuum adsorption, and then transferred to the heating area for preheating. The temperature of the heating zone is set at 80℃~130℃, and the effective heating time is 2S~10S. The base adhesive film on the interconnection film softens and adheres to the battery cell, and the interconnection strip is clamped between the base adhesive film and the back-contact solar cell to form an interconnection structure.

[0013] In the step S1, the interconnection film can be made in advance or simultaneously with the step S2.

[0014] Furthermore, in step S2, the interconnection film and the solar cell stack adopt the interconnection film to stack the cell: the interconnection film is laid flat on the conveyor belt with the front side facing upward and vacuum adsorbed, and the back-contact solar cell is arranged on the top of the interconnection film with the back side facing downward. The conveyor belt transports the interconnection film to just below the cell, and the cell is moved downward so that the electrodes on the back side thereof are stacked one by one with the interconnection strips on the interconnection film, so that the interconnection strips are in direct contact with the back electrodes of the back-contact solar cell, and the conveyor belt vacuum adsorbs and fixes the cell on the conveyor belt through a number of adsorption holes arranged on the interconnection film.

[0015] Furthermore, in step S2, the interconnection film and the solar cell stack adopt a cell stacking interconnection film: the back-contact solar cell is neatly laid one by one on the conveyor belt with the back side facing upward according to the series structure direction, the placement spacing of the cell is set according to the cell string design requirements, and the interconnection film is placed with the front side facing downward above the cell. The conveyor belt transports the cell to just below the interconnection film, and the interconnection film is moved downward. The interconnection strips on the interconnection film are stacked and covered with the electrodes on the back side of the cell placed on the conveyor belt, so that the interconnection strips are in direct contact with the back side electrodes of the back-contact solar cell, and the conveyor belt vacuum adsorbs and fixes the interconnection film on the conveyor belt through the spacing between adjacent cell sheets.

[0016] The benefits of the present invention are:

[0017] Compared with the prior art, the interconnection film of the present invention is formed online or offline, and there is no need to alternate between the battery cells and the interconnection strips, which greatly reduces the cycle time and improves the production capacity. Because the low-temperature stringing process is used throughout the process, it has the advantages of less stress and less warping compared to the conventional infrared welding process, reduces defects such as hidden cracks and scratches on the battery cells, and reduces the repair rate of battery strings. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] 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 show certain 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.

[0019] Figure 1 It is a schematic diagram of the structure of the interconnection membrane and the battery string of the present invention.

[0020] Figure 2 It is an exploded schematic diagram of the battery string of the present invention.

[0021] Figure 3 It is a schematic diagram of the process of battery string welding in Example 1.

[0022] Figure 4 It is a schematic diagram of the process of battery string welding in Example 2.

[0023] Main component symbols:

[0024] 1. Battery cells;

[0025] 2. Interconnection film, 21. Base adhesive film, 22. Interconnection strip;

[0026] 3. Conveyor belt;

[0027] 4. Battery string. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings of the specification. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] In the present invention, unless otherwise specified, directional words such as "up, down, left, right" are generally understood in combination with the directions shown in the drawings and actual applications.

[0030] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0031] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0032] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article. Among them, the terms "optional" and "optional" all mean that they may be included or not included (or may be present or not).

[0033] Embodiment 1:

[0034] 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 for connecting the plurality of solar cells 1 into a solar cell string 4 .

[0035] The interconnection film 2 is composed of a base adhesive film 21 and an interconnection strip 22. The length and width of the interconnection film 2 are designed based on the length and width of the battery string 4 plus the reserved size. The interconnection film 2 is divided into a front side and a back side. The front side of the interconnection film 2 is embedded with an interconnection strip 22 designed based on the battery electrode series structure. A part of the interconnection strip 22 is embedded in the adhesive film, while the other part protrudes from the adhesive film surface. The back side of the interconnection film 2 is a flat adhesive film surface. The interconnection strip 22 matches the electrode pattern on the back side of the battery cell 1. The base adhesive film of the interconnection film 2 adheres to the back side area of ​​the battery cell 1, and the interconnection strip 22 protruding from the interconnection film 2 contacts the electrode on the back side of the battery cell 1, connecting the battery cell 1 into a battery string 4.

[0036] The base film 21 has a gram weight of 50 g / m2 ~150g / m 2 .

[0037] The interconnection strip 22 is a round wire interconnection strip 22 or a flat interconnection strip 22 .

[0038] like Figure 3 As shown, the manufacturing process method of the back contact solar cell interconnection structure of this embodiment includes the following steps:

[0039] S1, making interconnection film 2: cutting interconnection strip 22 into a size that matches the back contact heterojunction solar cell electrode pattern and can connect the solar cells 1 in series, embedding interconnection strip 22 into the surface of base adhesive film 21 by preheating and pressing process, with the embedded side being the front side of interconnection film 2, with a part of interconnection strip 22 embedded into base adhesive film 21 and a part protruding out of the surface of base adhesive film 21;

[0040] S2, serial welding of interconnection film 2 and battery cell 1: lay the back-contact solar cell 1 with the back side facing upwards neatly on the conveyor belt 3 according to the direction of the serial structure, set the placement spacing of the battery cells 1 according to the design requirements of the battery string 4, and set the interconnection film 2 with the front side facing downwards above the battery cell 1. The conveyor belt 3 has an adsorption and fixing function, which adsorbs the battery cell 1 and conveys it to the bottom of the interconnection film 2. The stacking mechanism moves the interconnection film 2 downward, and the interconnection strips 22 on the interconnection film 2 are stacked and covered with the electrodes on the back of the battery cell 1 placed on the conveyor belt 3, so that the interconnection strips 22 are in direct contact with the back electrodes of the back-contact solar cell 1. The adsorption component on the conveyor belt 3 vacuum adsorbs and fixes the interconnection film 2 on the conveyor belt 3 through the spacing between adjacent battery cells 1. The stacked cells 1 and interconnection films 2 are then transferred to a heating area for preheating. The temperature of the heating area is set at 80°C to 130°C, and the effective heating time is 2S to 10S. The base adhesive film 21 on the interconnection film 2 softens and adheres to the cell 1. The interconnection strip 22 is sandwiched between the base adhesive film 21 and the back contact solar cell 1 to form an interconnection structure.

[0041] The interconnection film 2 may be fabricated in advance or simultaneously with step S2.

[0042] Compared with the prior art, the conventional back-contact solar cell interconnection method is to alternately operate a cell and a group of interconnection strips 22, and form a cell string 4 by infrared welding, which has a long cycle time and a high cracking rate. In this embodiment, the integrated interconnection film 2 is first made online or offline, and the cell 1 and the interconnection strips 22 do not need to be operated alternately, which greatly reduces the cycle time and improves production capacity. The arrangement and size of the interconnection strips 22 on the interconnection film 2 are designed according to the electrode arrangement of the cell 1 and the expected length of the cell string 4, and the low-temperature preheating stringing process is gentle, and the cracking rate is low.

[0043] Embodiment 2:

[0044] A plurality of adsorption holes are evenly distributed on the interconnection film 2 in the area not including the interconnection strips 22. Other features are consistent with those of the first embodiment.

[0045] The adsorption holes are mainly used for, when the interconnection film 2 is placed on the conveyor belt 3 and the battery cell 1 is stacked on the interconnection film 2, the adsorption component on the conveyor belt 3 can adsorb the battery cell 1 on the conveyor belt 3 through the adsorption holes, so that the interconnection film 2 and the battery cell 1 are tightly fitted.

[0046] like Figure 4 As shown, the manufacturing process method of the back contact solar cell interconnection structure of this embodiment includes the following steps:

[0047] S1. Making interconnection film 2: cutting interconnection strip 22 into a size that matches the electrode pattern of the back contact heterojunction solar cell and can connect the solar cells 1 in series, embedding interconnection strip 22 into the surface of base adhesive film 21 by preheating and pressing process, with the embedded side being the front side of interconnection film 2, a part of interconnection strip 22 being embedded into base adhesive film 21, and a part of it protruding out of the surface of base adhesive film 21; (consistent with Example 1).

[0048] S2, interconnection film 2 and cell 1 are welded in series: the interconnection film 2 is laid flat on the conveyor belt 3 with the front side facing upward and vacuum adsorbed, the back contact solar cell 1 is arranged on the top of the interconnection film 2 with the back side facing downward, the conveyor belt 3 conveys the interconnection film 2 to the bottom of the cell 1, the stacking mechanism moves the cell 1 downward, so that the electrodes on the back side of the cell are stacked one by one with the interconnection strips 22 on the interconnection film 2, so that the interconnection strips 22 are in direct contact with the back electrodes of the back contact solar cell 1, and the adsorption assembly on the conveyor belt 3 vacuum adsorbs and fixes the cell 1 on the conveyor belt 3 through a number of adsorption holes provided on the interconnection film 2. Then, the stacked cell 1 and the interconnection film 2 are conveyed to the heating area for preheating, the temperature of the heating area is set at 80℃~130℃, the effective heating time is 2S~10S, the base adhesive film 21 on the interconnection film 2 softens and adheres to the cell 1, and the interconnection strips 22 are sandwiched between the base adhesive film 21 and the back contact solar cell 1 to form an interconnection structure.

[0049] The interconnection film 2 may be fabricated in advance or simultaneously with step S2.

[0050] In summary, the present invention uses the interconnect film 2 for welding, which can not only greatly reduce the cycle time and improve production capacity, but also reduce defects such as hidden cracks and scratches on the battery cell 1 and reduce the rework rate of the battery string 4.

[0051] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A back contact solar cell interconnection structure, characterized in that: The invention comprises a plurality of battery cells (1) and an interconnection film (2) for connecting the plurality of battery cells (1) into a battery string (4); the interconnection film (2) is composed of a base adhesive film (21) and an interconnection strip (22); the interconnection strip (22) matches the electrode pattern on the back of the battery cell (1); a portion of the interconnection strip (22) is embedded in the base adhesive film (21), and a portion protrudes from the surface of the base adhesive film (21); the base adhesive film of the interconnection film (2) is adhered to the back area of ​​the battery cell (1), and the interconnection strip (22) protruding from the interconnection film (2) contacts the electrode on the back of the battery cell (1), thereby connecting the battery cells (1) into a battery string (4).

2. The back contact solar cell interconnection structure according to claim 1, characterized in that: The base adhesive film (21) has a gram weight of 50 g / m 2 ~150g / m 2 .

3. The back contact solar cell interconnection structure according to claim 1, characterized in that: The interconnection strip (22) is a round wire interconnection strip (22) or a flat interconnection strip (22).

4. The back contact solar cell interconnection structure according to claim 1, characterized in that: A plurality of adsorption holes are evenly distributed in the non-interconnection strip (22) region on the interconnection film (2).

5. A method for manufacturing a back contact solar cell interconnection structure according to any one of claims 1 to 4, characterized in that The following steps are involved: S1. Making an interconnection film (2): cutting the interconnection strip (22) into a size that matches the electrode pattern of the back contact heterojunction solar cell and can connect the solar cells (1) in series, embedding the interconnection strip (22) into the surface of the base adhesive film (21) by a preheating and pressing process, with the embedded side being the front side of the interconnection film (2), a part of the interconnection strip (22) being embedded in the base adhesive film (21), and a part protruding from the surface of the base adhesive film (21); S2, serial welding of the interconnection film (2) and the cell (1): the front side of the interconnection film (2) and the back side of the back-contact solar cell are laminated together, so that the interconnection strip (22) on the interconnection film (2) is in direct contact with the back electrode of the back-contact solar cell (1), and is fixed by vacuum adsorption, and then transferred to a heating area for preheating. The temperature of the heating area is set at 80°C to 130°C, and the effective heating time is 2S to 10S. The base adhesive film (21) on the interconnection film (2) is softened and adhered to the cell (1), and the interconnection strip (22) is sandwiched between the base adhesive film (21) and the back-contact solar cell (1) to form an interconnection structure; In step S1, the interconnection film (2) can be prepared in advance or simultaneously prepared with step S2.

6. The method for manufacturing a back contact solar cell interconnection structure according to claim 5, characterized in that: In the step S2, the interconnection film (2) and the solar cell stack are stacked by stacking the cell (1) with the interconnection film (2): the interconnection film (2) is laid flat on the conveyor belt (3) with the front side facing upward and vacuum adsorbed, the back-contact solar cell (1) is arranged above the interconnection film (2) with the back side facing downward, the conveyor belt (3) transports the interconnection film (2) to the bottom of the cell (1), the cell (1) is moved downward, and the electrodes on the back side of the interconnection film (2) are stacked one by one with the interconnection strips (22) on the interconnection film (2), so that the interconnection strips (22) are in direct contact with the back side electrodes of the back-contact solar cell (1), and the conveyor belt (3) vacuum adsorbs and fixes the cell (1) on the conveyor belt (3) through a plurality of adsorption holes provided on the interconnection film (2).

7. The method for manufacturing a back contact solar cell interconnection structure according to claim 5, characterized in that: In the step S2, the interconnection film (2) and the solar cell stack are stacked by stacking the interconnection film (2): the back-contact solar cell (1) is neatly laid one by one on the conveyor belt (3) according to the series structure direction with the back side facing upwards, the placement spacing of the solar cell (1) is set according to the design requirements of the solar cell string (4), the interconnection film (2) is placed above the solar cell (1) with the front side facing downwards, the conveyor belt (3) transports the solar cell (1) to the bottom of the interconnection film (2), the interconnection film (2) is moved downwards, the interconnection strips (22) on the interconnection film (2) are stacked and covered with the electrodes on the back side of the solar cell (1) placed on the conveyor belt (3), so that the interconnection strips (22) are in direct contact with the back side electrodes of the back-contact solar cell (1), and the conveyor belt (3) vacuum adsorbs and fixes the interconnection film (2) on the conveyor belt (3) through the spacing between adjacent solar cells (1).

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