Battery string fast repair method

Abstract

The application relates to the technical field of solar cells, in particular to a battery string rapid repair method. The battery string rapid repair method comprises the following steps: cutting the solder strip of a target cell piece in a battery string needing to be repaired, taking out the target cell piece, and forming a repair vacancy; cutting the solder strip of a cell piece in a battery string for repair, and obtaining a cell piece for repair; placing the cell piece for repair into the repair vacancy; welding the solder strip of the cell piece for repair with the solder strip of an adjacent cell piece, and forming a solder strip welding point; and printing insulating glue on the solder strip welding point. The battery string rapid repair method is simple in steps, easy to operate, can improve the repair efficiency of the battery string, reduces the displacement and scratching of the cell piece, improves the yield of the photovoltaic module, and saves the cost.

Description

Technical Field

[0001] This invention relates to the field of solar cell technology, and in particular to a method for rapid repair of solar cell strings. Background Technology

[0002] The positive and negative electrodes of the back contact battery are both designed on the back of the cell, which avoids optical loss caused by the front grid lines blocking the grid. This improves the short-circuit current and conversion efficiency of the battery. In addition, photovoltaic modules with back contact batteries have excellent performance such as low degradation, high temperature coefficient and aesthetics. Therefore, back contact batteries are increasingly favored by people.

[0003] Because the positive and negative electrodes of the back-contact battery are both located on the back side of the cell, welding of the back-contact battery to the solder ribbon is only performed on one side of the cell. Due to the difference in thermal expansion coefficients between crystalline silicon and metal solder ribbon, and the presence of insulating adhesive on the cell, the cell is prone to warping after high-temperature welding. During the manufacturing process of photovoltaic modules, the cells are susceptible to defects such as scratches and microcracks, resulting in a high probability of rework (string return rate).

[0004] Current methods for repairing back-contact solar cell strings primarily involve replacing the cells. This involves using a soldering iron to heat the solder ribbon at high temperature, separating it from multiple pads on the cell, removing the cell to be replaced, and then resoldering a new cell. This repair process is not only cumbersome but also requires specialized training for repair personnel. Furthermore, the repair process can easily cause relative displacement of the cells and scratches, reducing the yield rate of the repaired photovoltaic modules.

[0005] Therefore, there is an urgent need to design a rapid battery string repair method to solve the above technical problems. Summary of the Invention

[0006] The purpose of this invention is to propose a rapid rework method for battery strings, which is simple in steps, easy to operate, and can improve the rework efficiency of battery strings and increase the yield of photovoltaic modules.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] This invention provides a method for rapid rework of battery strings, comprising:

[0009] Cut the solder ribbon of the target cell in the battery string that needs to be repaired, remove the target cell, and create a repair space;

[0010] The solder strips of the cells in the battery string to be repaired are cut off to obtain the cells to be repaired. The cells to be repaired and the battery string to be repaired both use the same specifications of cells.

[0011] Place the battery cells to be repaired into the repair slots;

[0012] The solder strips of the battery cells to be repaired are welded to the solder strips of adjacent battery cells to form solder strip welding points.

[0013] Insulating adhesive is printed on the welding points of the welding strip.

[0014] As an optional technical solution for a rapid rework method for battery strings, the step of cutting the solder ribbon of the target battery cell in the battery string that needs rework, removing the target battery cell, and forming a rework vacancy includes:

[0015] Cut the solder strip 3mm-6mm from the inner edge of the target cell.

[0016] As an optional technical solution for a rapid rework method for battery strings, the step of cutting the solder strips of the battery cells in the battery string to be reworked and obtaining the battery cells for rework includes:

[0017] Cut the solder strip along the edge of the battery cell to be repaired.

[0018] As an optional technical solution for a rapid battery string repair method, the step of placing the battery cells to be repaired into the repair vacancy includes:

[0019] Tear the adhesive film along both long sides of the cell to be repaired, hold the torn adhesive film, and adjust the position of the cell to be repaired in the battery string that needs to be repaired.

[0020] As an optional technical solution for rapid rework of battery strings, the length of the adhesive film torn is not less than the length of the battery cell to be reworked.

[0021] As an optional technical solution for rapid rework of battery strings, the adhesive film is one of POE film, EVA film, PVB film or TPO film.

[0022] As an optional technical solution for a rapid battery string repair method, the step of welding the solder strips of the battery cell to be repaired to the solder strips of adjacent battery cells to form solder joints includes:

[0023] The solder ribbons of the battery cells to be repaired are spliced ​​together with the solder ribbons of adjacent battery cells to form a solder ribbon splice. The solder ribbon splice is then welded with a soldering iron to form a solder ribbon weld point.

[0024] As an optional technical solution for a rapid rework method for battery strings, the step of printing insulating adhesive at the welding points of the welding strip further includes:

[0025] Loosen the adhesive film and lay it on the battery cell to be repaired. Heat the adhesive film facing the solder joint to bond the adhesive film to the solder joint.

[0026] As an optional technical solution for a rapid rework method for battery strings, the width of the insulating adhesive is not less than the width of the welding point of the solder strip, and the length of the insulating adhesive is not less than the length of the welding point of the solder strip; and the insulating adhesive is a transparent insulating adhesive.

[0027] As an optional technical solution for rapid rework of battery strings, both the surface of the solder strip of the battery string to be reworked and the surface of the solder strip of the battery string used for rework are coated with flux.

[0028] The beneficial effects of the present invention include at least the following:

[0029] This invention provides a method for rapid rework of battery strings, comprising the following steps: cutting the solder ribbon of the target cell in the battery string requiring rework, removing the target cell to form a rework empty space; cutting the solder ribbon of the cells in the battery string to be reworked, obtaining the cells to be reworked; using the same specifications of cells in both the battery string to be reworked and the battery string requiring rework to maintain a constant power output of the photovoltaic module before and after rework; placing the cells to be reworked in the rework empty space; welding the solder ribbon of the cells to be reworked to the solder ribbon of adjacent cells to form a solder ribbon welding point; and printing insulating adhesive onto the solder ribbon welding point.

[0030] The above-described rapid battery string repair method only requires operators to cut the solder ribbon of the target battery cell from the battery string requiring repair, cut the solder ribbon of the battery cell to be repaired from the battery string, place the battery cell to be repaired in the repair slot to replace the target battery cell, then weld the solder ribbon of the battery cell to the solder ribbon of the adjacent battery cell to form a solder joint, and finally print insulating adhesive at the solder joint. This rapid battery string repair method is simple in its steps, eliminating the need for the existing method of using a soldering iron to heat the solder ribbon at high temperatures to separate the solder ribbon from multiple PAD points on the battery cell. Instead, it uses solder ribbon cutting to replace the target battery cell, making the operation faster and more efficient, saving repair time and improving work efficiency. Furthermore, the rapid battery string repair method in this application has lower difficulty requirements, making it applicable to more operators and saving labor costs. Furthermore, since the rapid rework method for battery strings in this application does not require separating the PAD points on the battery cells, it can reduce the relative displacement of the battery cells, lower the risk of scratches, and avoid the short circuits caused by solder dross generated during the high-temperature melting of PAD points in existing technologies. The rapid rework method for battery strings in this application can improve the product yield of photovoltaic modules. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the content of the embodiments of the present invention and these drawings without creative effort.

[0032] Figure 1 This is a flowchart illustrating the rapid repair method for battery strings provided in an embodiment of the present invention.

[0033] Figure 2 This is a schematic diagram of the structure of a battery cell for repair provided in an embodiment of the present invention;

[0034] Figure 3 This is a schematic diagram of the structure of a battery string that needs to be repaired, provided in an embodiment of the present invention;

[0035] Figure 4 This is a schematic diagram of the structure of the repaired battery string provided in an embodiment of the present invention;

[0036] Figure 5 This is a schematic diagram of the structure of the gridless back contact solar cell provided in an embodiment of the present invention.

[0037] Figure Labels

[0038] 100. Back contact cell without main grid; 110. Positive grid line; 120. Negative grid line; 130. Positive grid line isolation area; 140. Negative grid line isolation area; 150. Positive connecting metal line; 160. Negative connecting metal line;

[0039] 200, Target solar cell; 300, Solar cell for repair; 400, Insulating adhesive. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0041] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0042] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0043] In the description of this invention, it should be noted that the terms "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0044] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set" and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0045] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0046] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0047] This embodiment provides a method for rapid rework of battery strings. The steps are simple and easy to operate, which can improve the rework efficiency of battery strings, reduce the occurrence of displacement and scratches of battery cells, improve the yield of photovoltaic modules, and save costs.

[0048] like Figures 1-4 As shown, the rapid repair method for this battery string mainly includes the following steps:

[0049] Cut the solder strip of the target cell 200 in the battery string that needs to be repaired, remove the target cell 200, and form a repair empty space.

[0050] The solder ribbons of the cells in the battery string to be repaired are cut to obtain the cells 300 for repair. The cells used for repair and the battery string to be repaired both use the same specifications of cells to keep the power of the photovoltaic module constant before and after repair.

[0051] Place the 300 battery cell for repair into the repair slot.

[0052] The solder strips of the battery cell 300 used for repair are welded to the solder strips of the adjacent battery cell to form a solder strip welding point.

[0053] Print 400mm insulating adhesive on the welding points of the welding strip.

[0054] Based on the above design, this rapid battery string repair method only requires the operator to cut the solder ribbon of the target battery cell 200 from the battery string requiring repair, cut the solder ribbon of the battery cell 300 to be repaired from the battery string, place the battery cell 300 to be repaired in the repair slot to replace the target battery cell 200, then weld the solder ribbon of the battery cell 300 to the solder ribbon of the adjacent battery cell to form a solder ribbon welding point, and finally print insulating adhesive 400 at the solder ribbon welding point. This rapid battery string repair method is simple in steps and does not require the high-temperature heating of the solder ribbon with a soldering iron to separate the solder ribbon from the multiple PAD points on the battery cell in the existing technology. Instead, it uses the solder ribbon cutting method to replace the target battery cell 200, making the operation faster and more efficient, saving repair time and improving work efficiency. At the same time, the rapid battery string repair method in this embodiment has low difficulty requirements, can be applied to more operators, and saves labor costs. Furthermore, since the rapid rework method for battery strings in this embodiment does not require separating the PAD points on the battery cells, it can reduce the relative displacement of the battery cells, lower the risk of scratches, and avoid the short circuits caused by solder dross generated during the high-temperature melting of PAD points in existing technologies. Therefore, the rapid rework method for battery strings in this embodiment can improve the product yield of photovoltaic modules.

[0055] Alternatively, operators can use conventional scissors to cut the solder strips of the target cell 200 and the solder strips of the cell 300 used for repair, without using a soldering iron to melt the PAD points, thereby saving energy and costs.

[0056] Specifically, in this embodiment, the step of cutting the solder ribbon of the battery cell in the battery string that needs to be repaired, taking out the target battery cell 200, and forming a repair space includes: cutting the solder ribbon 3mm-6mm away from the inner edge of the target battery cell 200. This can preserve the length of the solder ribbon in the battery string that needs to be repaired as much as possible, improve welding performance, and reduce the risk of cold solder joints.

[0057] The step of cutting the solder ribbon of the cells in the battery string for repair to obtain the reworkable cell 300 includes cutting the solder ribbon along the edge of the reworkable cell 300. In other words, the solder ribbon of the reworkable cell 300 is flush with the cell, which minimizes the pulling action on the reworkable cell 300 during the cutting of the solder ribbon, and reduces the possibility of scratches or even breakage of the reworkable cell 300.

[0058] The step of placing the battery cell 300 for repair into the repair slot includes tearing the adhesive film along both long sides of the battery cell 300, clamping the torn adhesive film using a repair fixture, and adjusting the position of the battery cell 300 in the battery string that needs repair. Optionally, the length of the torn adhesive film is not less than the length of the battery cell 300 for repair, which facilitates the placement of the battery cell 300 for repair and avoids interference between the adhesive film and the battery cell 300 for repair.

[0059] Optionally, the tear length of the adhesive film can be set between 6mm and 8mm.

[0060] Optionally, the adhesive film in this embodiment is one of POE film, EVA film, PVB film or TPO film, thereby improving the flexibility and universality of adhesive film selection and saving costs.

[0061] It should be noted that the repair tooling is a conventional component in this field; therefore, its specific structure and working principle will not be described in detail in this embodiment.

[0062] In this embodiment, the step of welding the solder ribbon of the reworkable battery cell 300 to the solder ribbon of an adjacent battery cell to form a solder ribbon welding point includes splicing the solder ribbon of the reworkable battery cell 300 to the solder ribbon of an adjacent battery cell to form a solder ribbon splice, and then using a soldering iron to weld the solder ribbon splice to form a solder ribbon welding point. The solder ribbon splice is melted at high temperature using a soldering iron, allowing the solder ribbons on both sides to be welded together to form a solder ribbon welding point. Then, insulating adhesive 400 is printed at the solder ribbon welding point. Considering that the insulating adhesive 400 may affect the light absorption of the battery cell to some extent, in this embodiment, a transparent insulating adhesive 400 is used, and the insulating adhesive 400 is only printed at the solder ribbon welding point to improve the rework yield and reduce or avoid the problem of cold solder joints.

[0063] Optionally, in this embodiment, the width of the insulating adhesive 400 is not less than the width of the solder joint, and the length of the insulating adhesive 400 is not less than the length of the solder joint; and the insulating adhesive 400 is a transparent insulating adhesive. In this embodiment, the insulating adhesive 400 is printed only at the solder joint. The width of the printed insulating adhesive 400 can be set to 0.6mm-2mm, and the length of the insulating adhesive 400 can be set to 3.5mm-7.5mm, ensuring that the solder joint is within the printing range of the insulating adhesive 400, improving the stability and reliability of the connection between the solder joints on both sides, and ensuring a high rework yield.

[0064] Optionally, the insulating adhesive 400 in this embodiment has good high temperature resistance and can withstand a high temperature of 380°C.

[0065] In this embodiment, after the step of printing insulating adhesive 400 on the solder ribbon welding points, the rework tool loosens the adhesive film and lays the film on the battery cell 300 for rework. A soldering iron is used to heat the adhesive film opposite the solder ribbon welding points to bond and fix the welding points to the adhesive film. This achieves fixation between the adhesive film and the solder ribbon welding points, reduces displacement of the battery cell 300 for rework, and improves stability.

[0066] The battery strings repaired using this rapid rework method need to undergo a lamination process in a laminator. The lamination process consists of two steps: the first lamination temperature is set at 115℃-130℃, and the lamination time is 150s; the second lamination temperature is set at 145℃-155℃, and the lamination time is 600s.

[0067] Optionally, in this embodiment, both the surface of the solder strip of the battery string requiring repair and the surface of the solder strip used for repair are coated with flux. This facilitates the metallurgical bonding between the solder strip and the battery cell during the lamination process, improves the bonding force between the solder strip and the battery cell, and enhances the reliability of the photovoltaic module.

[0068] Optionally, the welding strip in this embodiment is a low-temperature welding strip, and the alloy composition is mainly SnPbBi, SnBiAg, etc., and the melting point of the welding strip coating alloy is 135℃-165℃.

[0069] like Figure 5As shown, this embodiment also provides a gridless back-contact battery string. The gridless back-contact battery string includes at least two gridless back-contact battery cells 100 and solder strips connecting adjacent gridless back-contact battery cells 100 in series. The back side of each gridless back-contact battery cell 100 has a plurality of parallel-arranged positive grid lines 110 and negative grid lines 120. The solder strips are connected in series on the same side (i.e., the back side) of the gridless back-contact battery cells 100. The positive grid lines 110 and negative grid lines 120 are parallel-arranged along a first direction, and the solder strips are perpendicularly overlapped with the positive grid lines 110 and negative grid lines 120. The solder strips include positive and negative conductors, which are alternately connected along a second direction to the positive grid lines 110 and negative grid lines 120 on the back side of adjacent gridless back-contact battery cells 100. The first direction is perpendicular to the second direction in the same plane.

[0070] The negative grid line 120 is formed by arranging multiple segments of negative grid lines 120 along the second direction, and a negative grid line isolation region 140 is provided between two adjacent negative grid lines 120. Similarly, the positive grid line 110 is formed by arranging multiple segments of positive grid lines 110 along the second direction, and a positive grid line isolation region 130 is provided between two adjacent positive grid lines 110. Correspondingly, the negative grid line isolation regions 140 and positive grid line isolation regions 130, which are arranged laterally at intervals, are staggered. The negative wire passes through the center of the positive grid line isolation region 130 without overlapping with the positive grid line 110, and the positive wire passes through the center of the negative grid line isolation region 140 without overlapping with the negative grid line 120, thereby avoiding short circuits.

[0071] For example, in this embodiment, the widths of the negative gate line isolation region 140 and the positive gate line isolation region 130 are the same, both of which can be set between 0.5mm and 1mm, and the widths of the negative gate line isolation region 140 and the positive gate line isolation region 130 are both greater than the width of the solder strip.

[0072] In this embodiment, the back side of the gridless back contact cell 100 is also provided with a positive electrode connection metal line 150 and a negative electrode connection metal line 160. The positive electrode connection metal line 150 and the negative electrode connection metal line 160 are both located at the edge of the gridless back contact cell 100, and are used independently to connect adjacent positive electrode grid lines 110 and adjacent negative electrode grid lines 120, respectively. This can avoid the risk of current not being collected due to the fine grid at the edge and the risk of short circuit caused by excessively long solder strips overlapping the cell, thereby improving the reliability of the photovoltaic module.

[0073] Optionally, in this embodiment, a large number of small-diameter round wire solder strips are used for high-precision placement. While ensuring power output, this avoids short circuits caused by solder strips overlapping the positive or negative electrode grids, thereby reducing the printing of insulating adhesive 400 and minimizing optical shading of the photovoltaic module. Simultaneously, using round wire solder strips also reduces backlight shading, improves secondary light utilization, and increases the bifaciality of the photovoltaic module.

[0074] Obviously, the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

[0075] Note that in the description of this specification, the references to terms such as "some embodiments," "other embodiments," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

Claims

1. A method for rapid rework of battery strings, characterized in that, include: Cut the solder ribbon of the target cell in the battery string that needs to be repaired, remove the target cell, and create a repair space; The solder strips of the cells in the battery string to be repaired are cut off to obtain the cells to be repaired. The cells to be repaired and the battery string to be repaired both use the same specifications of cells. Place the battery cells to be repaired into the repair slots; The solder strips of the battery cells to be repaired are welded to the solder strips of adjacent battery cells to form solder strip welding points. Insulating adhesive is printed on the welding points of the welding strip.

2. The rapid rework method for battery strings according to claim 1, characterized in that, The step of cutting the solder ribbon of the target cell in the battery string that needs to be repaired, removing the target cell, and forming a repair vacancy includes: Cut the solder strip 3mm-6mm from the inner edge of the target cell.

3. The rapid rework method for battery strings according to claim 1, characterized in that, The step of cutting the solder strips of the cells in the battery string to obtain the cells for repair includes: Cut the solder strip along the edge of the battery cell to be repaired.

4. The rapid rework method for battery strings according to claim 1, characterized in that, The step of placing the battery cells for repair into the repair vacancy includes: Tear the adhesive film along both long sides of the cell to be repaired, hold the torn adhesive film, and adjust the position of the cell to be repaired in the battery string that needs to be repaired.

5. The rapid rework method for battery strings according to claim 4, characterized in that, The length of the film torn should not be less than the length of the battery cell to be repaired.

6. The rapid rework method for battery strings according to claim 4, characterized in that, The film is one of POE film, EVA film, PVB film or TPO film.

7. The rapid rework method for battery strings according to claim 4, characterized in that, The step of welding the solder strip of the battery cell to be repaired to the solder strip of an adjacent battery cell to form a solder strip weld joint includes: The solder ribbons of the battery cells to be repaired are spliced ​​together with the solder ribbons of adjacent battery cells to form a solder ribbon splice. The solder ribbon splice is then welded with a soldering iron to form a solder ribbon weld point.

8. The rapid rework method for battery strings according to claim 7, characterized in that, The step of printing insulating adhesive at the welding points of the welding strip further includes: Loosen the adhesive film and lay it on the battery cell to be repaired. Heat the adhesive film facing the solder joint to bond the adhesive film to the solder joint.

9. The method for rapid rework of battery strings according to any one of claims 1-8, characterized in that, The width of the insulating adhesive is not less than the width of the welding point of the welding strip, and the length of the insulating adhesive is not less than the length of the welding point of the welding strip; and the insulating adhesive is a transparent insulating adhesive.

10. The method for rapid rework of battery strings according to any one of claims 1-8, characterized in that, Both the surface of the solder strips on the battery string that needs to be repaired and the surface of the solder strips on the battery string used for repair are coated with flux.

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