Photovoltaic module

Abstract

The application discloses a photovoltaic module, and relates to the technical field of photovoltaic technology. The photovoltaic module comprises a cell piece and a solder strip. The cell piece comprises a cell base body, a plurality of grid lines and a plurality of pads arranged on the cell base body, the pads are connected to the grid lines, the plurality of pads are arranged in a plurality of columns on the cell base body, the plurality of pads in the same column are arranged at intervals in a first direction, the solder strip is connected to the plurality of pads in the same column, and the size of the solder strip in a second direction is greater than the size of the pad in the second direction, wherein the second direction is perpendicular to the first direction. In the application, the width of the solder strip is greater than the width of the pad, so that the solder strip can cover the pad during pre-fixing. Even if the solder strip deviates a certain amount during subsequent lamination, the solder strip will not be separated from the pad, so that sufficient welding area is ensured. Therefore, the welding reliability between the pad and the solder strip of the photovoltaic module is better, and the product yield is higher.

Description

Technical Field

[0001] This application relates to the field of photovoltaic technology, and more specifically, to a photovoltaic module. Background Technology

[0002] In photovoltaic (PV) modules, the solder ribbons serve to collect and transmit the current generated by the solar cells. Because the grid lines on the solar cells are relatively thin, solder pads are provided on the cells to connect to the grid lines, ensuring reliable electrical connection between the solder ribbon and the grid lines. The width of the solder pads is larger than the width of the grid lines to facilitate soldering with the solder ribbon. Typically, the solder ribbon connects to multiple solder pads arranged in a row on the solar cell, and the width of the solder ribbon is smaller than the width of the solder pads. However, during the manufacturing process of PV modules, the solder ribbons need to be pre-fixed before lamination. During pre-fixation, the two ends of the solder ribbon are secured with adhesive. During the vacuuming, heating, and pressurization process in the laminator, the molten encapsulating film (EVA / POE, etc.) flows, generating lateral shear forces that can easily pull and cause the solder ribbon to shift or twist. This is especially true in the middle of the solder ribbon, which is farther from the pre-fixing points at both ends, making it more prone to lateral shift. When the solder ribbon shifts or twists, the contact area between the solder ribbon and the solder pads may be too small or even lost, leading to poor soldering reliability or soldering failure. Summary of the Invention

[0003] The purpose of this application is to provide a photovoltaic module that can improve the problem of poor welding effect or even connection failure between the solder strip and the pad due to solder strip misalignment.

[0004] The embodiments of this application can be implemented as follows: In a first aspect, this application provides a photovoltaic module, including a cell and a solder ribbon. The cell includes a cell substrate and a plurality of grid lines and a plurality of solder pads disposed on the cell substrate. The solder pads are connected to the grid lines. The plurality of solder pads are arranged in multiple columns on the cell substrate. The plurality of solder pads in the same column are spaced apart in a first direction. The solder ribbon is connected to the plurality of solder pads in the same column. The size of the solder ribbon in a second direction is larger than the size of the solder pads in the second direction. The second direction is perpendicular to the first direction.

[0005] In an optional embodiment, the solder strip has a dimension of 0.4 mm to 2 mm in the second direction, and the solder pad has a dimension of 0.05 mm to 0.5 mm in the second direction.

[0006] In an optional embodiment, the section of the battery cell covered by the solder ribbon is called the covered section, and the width of the two ends of the covered section in the first direction is smaller than the width of the middle section, and the width direction of the covered section is the second direction.

[0007] In an optional implementation, the coverage segment includes a first segment, a middle segment, and a last segment arranged sequentially in a first direction, each of the first segment, middle segment, and last segment having a uniform width; the width of the first segment and the last segment is smaller than the width of the middle segment.

[0008] In an optional implementation, the width of the coverage area gradually increases from both ends toward the middle.

[0009] In an optional implementation, the ratio of the width at both ends of the coverage section to the dimension of the pad in the second direction is 1.2 to 1.8; the ratio of the width at the widest point in the middle of the coverage section to the dimension of the pad in the second direction is 1.8 to 3.

[0010] In an optional embodiment, the solder strip has two top cylinders on the side away from the cell in its thickness direction, the two top cylinders are arranged side by side in a second direction, and the axes of the two top cylinders extend along the first direction.

[0011] In an optional embodiment, the welding strip has a connecting surface that adheres to the battery cell, and the welding strip also has reflective slopes on both sides in the second direction. The reflective slopes connect the connecting surface and the top cylindrical surface, and the angle between the reflective slopes and the connecting surface is an acute angle with a chamfer at the connection.

[0012] In an optional embodiment, the thickness of the solder strip is 0.05 mm to 0.5 mm.

[0013] In an optional implementation, the battery cell type is a back-contact battery.

[0014] The beneficial effects of the photovoltaic modules provided in this application include: The photovoltaic module provided in this application includes solar cells and solder ribbons. The solar cell includes a cell substrate and multiple grid lines and solder pads disposed on the cell substrate. The solder pads are connected to the grid lines, and the multiple solder pads are arranged in multiple columns on the cell substrate. Multiple solder pads in the same column are spaced apart in a first direction. The solder ribbon is connected to the multiple solder pads in the same column. The dimension of the solder ribbon in a second direction is larger than the dimension of the solder pads in the same second direction, wherein the second direction is perpendicular to the first direction. The dimension of the solder ribbon in the second direction is the width of the solder ribbon. In this application, the width of the solder ribbon is set to be greater than the width of the solder pads. This allows the solder ribbon to cover the solder pads during pre-fixation, and even if the solder ribbon shifts to a certain extent during subsequent lamination, it will not separate from the solder pads, thus ensuring sufficient welding area. Furthermore, compared to narrower solder ribbons, wider solder ribbons have better resistance to shifting and twisting. After the two ends of the solder ribbon are pre-fixed, the shift in the middle of the solder ribbon is smaller, making it less likely to separate from the solder pads located in the middle of a row. Therefore, the photovoltaic module provided in this application has better welding reliability between the solder pads and the solder ribbon, resulting in a higher product yield. Attached Figure Description

[0015] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram illustrating the displacement of the solder ribbon on the solar cell in related technologies; Figure 2 This is a partial schematic diagram of a photovoltaic module in the first embodiment of this application; Figure 3 This is a schematic diagram showing the solder strip after a certain offset in the first embodiment of this application; Figure 4 This is a partial schematic diagram of the photovoltaic module in the second embodiment of this application; Figure 5 This is a schematic diagram showing the solder strip after a certain displacement in the second embodiment of this application; Figure 6 This is a partial schematic diagram of the photovoltaic module in the third embodiment of this application; Figure 7 This is a schematic diagram showing the solder strip after a certain displacement in the third embodiment of this application; Figure 8 This is a partial cross-sectional view of a photovoltaic module in one embodiment of this application; Figure 9 This is a partial cross-sectional view of a photovoltaic module in another embodiment of this application.

[0017] Icons: 100-Battery cell; 110-Battery substrate; 120-Solder pad; 200-Solder ribbon; 201-First section; 202-Middle section; 203-Tail section; 210-Top cylindrical surface; 220-Connecting surface; 230-Reflective bevel; 300-Fixing adhesive; 400-Glass plate; 500-Adhesive film. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0019] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0020] 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.

[0021] In the description of this application, it should be noted that if terms such as "upper," "lower," "inner," or "outer" are used to indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of the invention is usually placed during use, they are only for the convenience of describing this application and 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, and therefore should not be construed as a limitation of this application.

[0022] Furthermore, the terms "first" and "second" are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0023] It should be noted that, where there is no conflict, the features in the embodiments of this application can be combined with each other.

[0024] During the manufacturing process of photovoltaic modules, the solder ribbons typically need to be pre-fixed before lamination welding. During pre-fixation, the two ends of the solder ribbons are secured by applying adhesive. During lamination welding, the molten encapsulating film flows, generating lateral shear force, which can easily cause the solder ribbons to shift or twist. Figure 1 This is a schematic diagram illustrating the offset of the solder ribbon 200 on the solar cell 100 in related technologies. Figure 1 As shown, the middle of the solder ribbon 200, far from the fixing adhesive 300 at both ends, lacks fixation with the battery cell 100, making it prone to misalignment. When the solder ribbon 200 misaligns and separates from the pad 120, or when the contact area is too small, it can lead to soldering failure or decreased soldering reliability, resulting in a lower product yield. If the area of ​​the pad 120 is increased to accommodate the misalignment of the solder ribbon 200, the material used for the pad 120 will increase significantly. Since the pad 120 is often made of silver, increasing its size will significantly increase material costs.

[0025] Therefore, this application provides a photovoltaic module that improves the resistance to displacement and torsion of the solder ribbon by setting the width of the solder ribbon to be greater than the width of the solder pad. Simultaneously, even if the solder ribbon shifts to a certain extent, it can maintain sufficient contact area with the solder pad, ensuring welding reliability. Furthermore, the material cost of the solder ribbon is lower than that of the grid lines and solder pads, thus resulting in lower overall cost.

[0026] Figure 2 This is a partial schematic diagram of a photovoltaic module in the first embodiment of this application; Figure 3 This is a schematic diagram showing the solder strip 200 after a certain offset in the first embodiment of this application. Figure 2 and Figure 3 As shown, this application provides a photovoltaic module, including a cell 100 and a solder ribbon 200. The cell 100 includes a cell substrate 110 and a plurality of grid lines and a plurality of solder pads 120 disposed on the cell substrate 110. The solder pads 120 are connected to the grid lines. The plurality of solder pads 120 are arranged in multiple columns on the cell substrate 110. The plurality of solder pads 120 in the same column are spaced apart in a first direction. The solder ribbon 200 is connected to the plurality of solder pads 120 in the same column. The size of the solder ribbon 200 in a second direction is larger than the size of the solder pads 120 in the second direction. The second direction is perpendicular to the first direction.

[0027] To better illustrate the positional relationship between the solder ribbon 200 and the pad 120, the grid lines are not shown in the accompanying drawings of this application; however, the pads 120 covered by the solder ribbon 200 are also shown. Optionally, the grid lines extend along a second direction, and the dimension of the grid lines in the first direction (i.e., the width of the grid lines) is smaller than the dimension of the pads 120 in the first direction. Optionally, the cell 100 is a back-contact cell, meaning that the solder ribbon 200, the pads 120, and the grid lines are all located on the back surface of the cell 100. Optionally, the grid lines connected to the pads 120 are fine grids (or sub-grids). Optionally, the grid lines connected to adjacent rows of pads 120 have different polarities; that is, one row of adjacent rows of pads 120 connects to the N-type region of the cell 100, and the other row connects to the P-type region of the cell 100.

[0028] In this embodiment, the dimension of the solder ribbon 200 in the second direction, i.e., the width of the solder ribbon 200, is set to be greater than the width of the pad 120. This allows the solder ribbon 200 to completely cover the pad 120 when pre-fixed to the battery cell 100 (e.g., ...). Figure 2 Even if the solder strip 200 shifts to a certain extent during subsequent lamination (e.g. Figure 3It will not separate from the pad 120, thus ensuring sufficient soldering area. Moreover, compared to the narrower solder ribbon 200, the wider solder ribbon 200 itself has better resistance to offset and torsion. After the two ends of the solder ribbon 200 are pre-fixed with the fixing adhesive 300, the offset of the middle part of the solder ribbon 200 is smaller, and it is not easy to separate from the pad 120 in the middle of a row.

[0029] Furthermore, the material of the solder ribbon 200 is less expensive than that of the pad 120. For example, the pad 120 and the grid lines are made of silver, while the solder ribbon 200 can be made of copper, i.e., a copper substrate with a tin layer wrapped around it. Therefore, widening the solder ribbon 200 will not result in a significant increase in cost. Moreover, since the solder ribbon 200 is less likely to separate from the pad 120 due to misalignment in this embodiment, the size of the pad 120 can be appropriately reduced (compared to traditional photovoltaic modules), further lowering the material cost of the pad 120.

[0030] Optionally, the solder strip 200 is a strip with a uniform width. Optionally, the solder strip 200 has a dimension of 0.4mm to 2mm in the second direction, and the pad 120 has a dimension of 0.05mm to 0.5mm in the second direction. Optionally, the pad 120 has a dimension of 0.1mm to 1mm in the first direction.

[0031] Figure 4 This is a partial schematic diagram of the photovoltaic module in the second embodiment of this application; Figure 5 This is a schematic diagram showing the solder strip 200 after a certain offset in the second embodiment of this application. Figure 4 and Figure 5 As shown, the section of the solder ribbon 200 covering the battery cell 100 is called the coverage section. The width of the two ends of the coverage section of the solder ribbon 200 in the first direction is smaller than the width of the middle section, and the width direction of the coverage section is the second direction. In this embodiment, the width of the solder ribbon 200 is not uniform. Since only the coverage section of the solder ribbon 200 covering the battery cell 100 has a connection with the pad 120, while the part outside the edge of the battery cell 100 has no connection with the pad 120, this application only discusses the width distribution of the coverage section. Since the middle of the coverage section is far from the fixing adhesive 300, the offset of the middle of the coverage section in the second direction will be greater than the offset of the two ends in the second direction. Therefore, in this embodiment, the width of the middle of the coverage section is set to be greater than the width of the two ends, so that the middle can better accommodate the offset of the middle. In other words, even if the middle of the coverage section has a large offset, because it has a large width, it is not easy to separate from the pad 120, thus ensuring the welding effect. In addition, due to the greater width in the middle, the resistance to bending and torsion is improved.

[0032] Optionally, the ratio of the width at both ends of the coverage section to the dimension of the pad 120 in the second direction is 1.2 to 1.8; the ratio of the width at the widest point in the middle of the coverage section to the dimension of the pad 120 in the second direction is 1.8 to 3.

[0033] In this embodiment, the coverage segment includes a first segment 201, a middle segment 202, and a last segment 203 arranged sequentially in the first direction. Each of the first segment 201, the middle segment 202, and the last segment 203 has a uniform width; the widths of the first segment 201 and the last segment 203 are both smaller than the width of the middle segment 202. Optionally, the ratio of the width of the first segment 201 and the last segment 203 to the dimension of the pad 120 in the second direction is 1.2 to 1.8; the ratio of the width of the middle segment 202 to the dimension of the pad 120 in the second direction is 1.8 to 3.

[0034] Figure 6 This is a partial schematic diagram of the photovoltaic module in the third embodiment of this application; Figure 7 This is a schematic diagram showing the solder strip 200 after a certain offset in the third embodiment of this application. Figure 6 and Figure 7 As shown, in this embodiment, the width of the covered section gradually increases from both ends towards the middle. This gradually varying width of the solder strip 200 also allows for larger offsets.

[0035] In this embodiment, the solder ribbon 200 can be a flat solder ribbon, meaning the thickness of the solder ribbon 200 is less than its width. When light shines on the flat solder ribbon 200, the solder ribbon 200 absorbs or reflects the light, rendering that portion of the light unusable. Figure 8 This is a partial cross-sectional view of a photovoltaic module in one embodiment of this application. Figure 8 As shown, the photovoltaic module also includes a glass plate 400, which is arranged parallel to and spaced apart from the solar cell 100. A solder ribbon 200 is located between the glass plate 400 and the solar cell 100, and an adhesive film 500 is filled between the solar cell 100 and the glass plate 400. When the solar cell 100 is a back-contact cell, the glass plate 400 is the backsheet glass.

[0036] To reduce the negative impact of the solder ribbon 200 on the light absorption efficiency of the solar cell 100, the solder ribbon 200 can optionally be configured as a triangular prism structure, i.e., the cross-section is triangular. One of the three faces of the solder ribbon 200 is connected to the surface of the solar cell 100, and when light shines on the other two faces, it can be reflected to the solar cell 100, thereby improving the light absorption rate of the solar cell 100.

[0037] However, the corners of the triangular cross-section solder ribbon 200 are acute, which can lead to poor tin coating at the corners, easily exposing the internal copper substrate. This results in oxidation of the copper substrate of the solder ribbon 200, increasing resistance and affecting power and reliability. Furthermore, the cross-sectional area of ​​the solder ribbon 200 should not be too small to avoid excessive resistance. For the same cross-sectional area, a triangular cross-section solder ribbon 200 would be thicker, making it more prone to cracking the solar cell 100 during lamination. Therefore, the thickness of the adhesive film 500 needs to be increased. Increasing the thickness of the adhesive film 500 not only increases cost but also increases fluidity, making it easier for the solder ribbon 200 to shift.

[0038] Therefore, this application provides a welding strip 200 with an alternative structure. Figure 9 This is a partial cross-sectional view of a photovoltaic module according to another embodiment of this application. Figure 9 As shown, in this embodiment, the solder ribbon 200 has two top cylindrical surfaces 210 on the side away from the battery cell 100 in its thickness direction (perpendicular to the first and second directions). The two top cylindrical surfaces 210 are arranged side by side in the second direction, and the axes of the two top cylindrical surfaces 210 extend along the first direction. Compared with the solder ribbon 200 with a triangular cross-section, the sharp angle at the top is eliminated, improving the problem of poor solder layer encapsulation. In addition, with the same cross-sectional area, the solder ribbon 200 in this embodiment has a relatively small thickness, which helps to reduce the risk of battery cell 100 breakage during lamination and reduce the amount of adhesive film 500 used. Optionally, the thickness of the solder ribbon 200 is 0.05mm to 0.5mm.

[0039] When light shines on the top cylindrical surface 210 in the direction perpendicular to the solar cell 100, it will be obliquely reflected by the top cylindrical surface 210. Part of the light will be reflected to the solar cell 100, and part of the light will be reflected to the glass plate 400, and then reflected to the surface of the solar cell 100. Compared with the flat solder ribbon 200, this is beneficial to improve the light absorption efficiency of the solar cell 100.

[0040] Furthermore, in this embodiment, the solder ribbon 200 has a connecting surface 220 that adheres to the battery cell 100. The solder ribbon 200 also has reflective inclined surfaces 230 on both sides in the second direction. The reflective inclined surfaces 230 connect the connecting surface 220 and the top cylindrical surface 210. The angle between the reflective inclined surfaces 230 and the connecting surface 220 is acute, and a chamfer is provided at the connection point. Therefore, in this embodiment, the cross-section of the solder ribbon 200 can be considered as a trapezoid combined with two semicircles. The lower base of the trapezoid is connected to the battery cell 100, and the two semicircles are arranged side-by-side on the upper base of the trapezoid. Furthermore, the acute angle between the reflective inclined surfaces 230 and the connecting surface 220 allows light irradiated by the reflective inclined surfaces 230 to be reflected back to the battery cell 100, improving the light absorption efficiency of the battery cell 100. The chamfer at the connection point between the reflective inclined surfaces 230 and the connecting surface 220 avoids the formation of sharp edges, thereby improving the encapsulation of the tin layer at this location and enhancing the corrosion resistance of the solder ribbon 200.

[0041] Optionally, the welding strip 200 can be plastically drawn through a die, making the manufacturing process highly efficient.

[0042] In summary, the photovoltaic module provided in this application includes a cell 100 and a solder ribbon 200. The cell 100 includes a cell substrate 110 and multiple grid lines and multiple solder pads 120 disposed on the cell substrate 110. The solder pads 120 are connected to the grid lines. The multiple solder pads 120 are arranged in multiple columns on the cell substrate 110. The multiple solder pads 120 in the same column are spaced apart in a first direction. The solder ribbon 200 is connected to the multiple solder pads 120 in the same column. The dimension of the solder ribbon 200 in a second direction is larger than the dimension of the solder pads 120 in the second direction, wherein the second direction is perpendicular to the first direction. The dimension of the solder ribbon 200 in the second direction is the width of the solder ribbon 200. In this application, the width of the solder ribbon 200 is set to be larger than the width of the solder pads 120. This allows the solder ribbon 200 to cover the solder pads 120 during pre-fixation. Even if the solder ribbon 200 shifts to a certain extent during subsequent lamination, it will not separate from the solder pads 120, thereby ensuring sufficient welding area. Furthermore, compared to a narrower solder strip 200, a wider solder strip 200 inherently possesses better resistance to offset and torsion. After the ends of the solder strip 200 are pre-fixed, the offset in the middle of the solder strip 200 is smaller, making it less prone to separation from the pads 120 located in the middle of a row. Therefore, the photovoltaic module provided in this application exhibits better welding reliability between the pads 120 and the solder strip 200, resulting in a higher product yield.

[0043] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application.

Claims

1. A photovoltaic module, characterized in that, The device includes a battery cell and a solder ribbon. The battery cell includes a battery substrate and a plurality of grid lines and a plurality of solder pads disposed on the battery substrate. The solder pads are connected to the grid lines. The plurality of solder pads are arranged in multiple columns on the battery substrate. The plurality of solder pads in the same column are spaced apart in a first direction. The solder ribbon is connected to the plurality of solder pads in the same column. The size of the solder ribbon in a second direction is larger than the size of the solder pads in the second direction. The second direction is perpendicular to the first direction.

2. The photovoltaic module according to claim 1, characterized in that, The solder strip has a size of 0.4mm to 2mm in the second direction, and the pad has a size of 0.05mm to 0.5mm in the second direction.

3. The photovoltaic module according to claim 1, characterized in that, The section of the solder strip that covers the battery cell is called the covering section. The width of the covering section of the solder strip at both ends in the first direction is smaller than the width in the middle. The width direction of the covering section is the second direction.

4. The photovoltaic module according to claim 3, characterized in that, The coverage area includes a first segment, a middle segment, and a last segment arranged sequentially in the first direction, each of the first segment, the middle segment, and the last segment having a uniform width; the width of the first segment and the last segment is smaller than the width of the middle segment.

5. The photovoltaic module according to claim 3, characterized in that, The width of the covered section gradually increases from both ends toward the middle.

6. The photovoltaic module according to claim 3, characterized in that, The ratio of the width at both ends of the coverage section to the dimension of the pad in the second direction is 1.2 to 1.8; the ratio of the width at the widest point in the middle of the coverage section to the dimension of the pad in the second direction is 1.8 to 3.

7. The photovoltaic module according to claim 1, characterized in that, The welding strip has two top cylindrical surfaces on the side away from the battery cell in its thickness direction. The two top cylindrical surfaces are arranged side by side in the second direction, and the axes of the two top cylindrical surfaces extend along the first direction.

8. The photovoltaic module according to claim 7, characterized in that, The welding strip has a connecting surface that adheres to the battery cell. The welding strip also has reflective inclined surfaces on both sides in the second direction. The reflective inclined surfaces connect the connecting surface and the top cylindrical surface. The angle between the reflective inclined surfaces and the connecting surface is an acute angle, and a chamfer is provided at the connection point.

9. The photovoltaic module according to any one of claims 1-8, characterized in that, The thickness of the welding strip is 0.05mm to 0.5mm.

10. The photovoltaic module according to any one of claims 1-8, characterized in that, The type of battery cell is a back contact battery.

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