Anti-warping back contact type photovoltaic module
By employing a folded, wave-shaped main grid and fine grid structure in back-contact photovoltaic modules, welding stress is decomposed, the warping problem after welding is solved, and the production yield and welding quality of the cells are improved.
Patent Information
- Application Number
- CN202423109297.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-16
- Publication Date
- 2025-11-25
- Estimated Expiration
- 2034-12-16
AI Technical Summary
After welding, the mismatch in thermal expansion coefficients between the solder ribbon and the cell material in back-contact photovoltaic cells can cause cell warping, affecting production yield.
The structure employs a folded wave-shaped main grid and fine grid, with the solder strip located above the main grid. The stress at the welding point between the main grid and the solder strip is decomposed into stresses directed toward the fine grid and the main grid. By setting the positive fine grid to not contact the negative main grid, the main grid corner to be an obtuse angle, and the solder strip to be perpendicularly connected to the fine grid, the stress is decomposed to reduce the warpage.
It effectively reduced the warpage of the battery cells, improved welding quality and production yield, and prevented short circuits.
Smart Images
Figure CN223600265U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to photovoltaic module technical field, concretely is a kind of back contact photovoltaic module of warping prevention. BACKGROUND
[0002] The positive and negative electrodes of back contact photovoltaic cell are located at the back of cell, and are arranged alternately, because the electrode is all in back, so back contact photovoltaic module front no solder strip.Solar light can be maximally irradiated to cell surface without electrode grid line shielding, increase effective light receiving area, reduce the current loss caused by front grid line shielding, so that more photons can produce electron hole pair in cell, thereby improve the absorption and utilization efficiency of cell to light energy.
[0003] The material of solder strip and cell is different, and the thermal expansion coefficient is different, there is stress after welding, because the positive and negative electrodes of back contact photovoltaic cell are located at the back of cell, solder strip is located at the back of cell piece after welding, cell piece will warp due to residual stress after welding to the side with solder strip, and serious warping can lead to cell piece breakage in subsequent processing procedure, affect production yield.
[0004] Therefore, how to improve welding warping becomes a problem to be solved by the person skilled in the art. INVENTION CONTENTS
[0005] To solve the technical problem in the background art, the utility model discloses a kind of back contact photovoltaic module of warping prevention.
[0006] The utility model provides a kind of back contact photovoltaic module of warping prevention, including base body, the back side of base body is provided with vertical main grid and fine grid, fine grid is composed of positive fine grid and negative fine grid of alternate interval arrangement, main grid is composed of positive main grid and negative main grid of alternate interval arrangement;
[0007] Main grid is folded wave shape;
[0008] Solder strip is located above main grid, and solder strip and main grid coincide in overhead projection.
[0009] The fold line shape arrangement of main grid makes that the stress F generated at the welding of main grid and solder strip can be decomposed into Fx towards fine grid direction and Fy towards main grid direction, since Fx and Fy are all less than F, so the warping amplitude of cell piece can be greatly reduced, and welding quality is improved.
[0010] Since main grid and fine grid are generally connected together, this structure is applied to back contact photovoltaic module, and short circuit phenomenon is easy to generate, based on this, further improvement lies in: positive fine grid is broken at the position of negative main grid, so that it does not contact with negative main grid;Negative fine grid is broken at the position of positive main grid, so that it does not contact with positive main grid.
[0011] The included angle between the main grid and the bending part of the solder strip directly affects the warping range of the battery sheet, and based on this, the further improvement is that an obtuse angle is formed at the corner of the main grid.
[0012] Further, the end points of the two ends of the main grid are E and S, the line segment between E and S and the adjacent corner point thereof is the head-tail segment, a plurality of intermediate segments are arranged between the head-tail segment, the center line of the main grid in the width direction is Y, the included angle between the head-tail segment and Y is ∠a, the included angle between the intermediate segment and Y is ∠b, and the range of ∠a and ∠b is 10-45°. The reasons for such arrangement are: 1, the greater the angle, the easier the deformation; 2, it is beneficial to the preparation and use of the zigzag solder strip.
[0013] Wherein ∠a = ∠b, and the length of the head-tail segment is half of the length of the intermediate segment. In this way, the symmetry is better, and the stress is more uniform.
[0014] If the solder strip is located in the external region of E and S and extends in the direction of the head-tail segment, its position is difficult to match the output circuit, and the connection is difficult, and based on this, the further improvement is that the external region of E and S where the solder strip is located is perpendicular to the fine grid.
[0015] The beneficial effects of the utility model are: the zigzag arrangement of the main grid makes each segment of the main grid form an included angle with the solder strip, so that the stress F generated at the welding position of the main grid and the solder strip is decomposed into Fx towards the fine grid and Fy towards the main grid, and since Fx and Fy are both smaller than F, the warping range of the battery sheet can be greatly reduced, and the performance of the battery sheet will not be affected. BRIEF DESCRIPTION OF DRAWINGS
[0016] The utility model will be further described below in combination with the drawings and examples.
[0017] Figure 1 is the structure schematic diagram of the utility model, wherein the solder strip is hidden;
[0018] Figure 2 is the structure schematic diagram of the utility model, wherein the solder strip is contained;
[0019] Figure 3 is the stress analysis diagram in the utility model;
[0020] Figure 4 is the traditional stress analysis diagram;
[0021] In the drawing: 1, base body; 2, positive fine grid; 3, negative fine grid; 4, positive main grid; 5, negative main grid; 6, solder strip; 7, head-tail segment; 8, intermediate segment. DETAILED DESCRIPTION
[0022] The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, illustrating only the basic structure of the present invention, and therefore only show the components relevant to the present invention.
[0023] like Figure 1 As shown, this utility model discloses an anti-warping back-contact photovoltaic module, including a substrate 1. The back side of the substrate 1 is provided with a vertical main grid and a fine grid. The fine grid is composed of alternating positive fine grids 2 and negative fine grids 3. The main grid is composed of alternating positive main grids 4 and negative main grids 5.
[0024] The positive electrode fine grid 2 is interrupted at the position of the negative electrode main grid 5, so that it is not in contact with the negative electrode main grid 5; the negative electrode fine grid 3 is interrupted at the position of the positive electrode main grid 4, so that it is not in contact with the positive electrode main grid 4. This setting avoids the occurrence of short circuits.
[0025] The main grid has a folded, wavy shape, with obtuse angles at its corners. Specifically: the endpoints of the main grid are designated as E and S; the line segments between E, S and their adjacent corner points are designated as the first and last segments 7; multiple intermediate segments 8 are designated between the first and last segments 7; the centerline of the main grid in the width direction is designated as Y; the angle between the first and last segments 7 and Y is designated as ∠a; the angle between the intermediate segments 8 and Y is designated as ∠b; the range of ∠a and ∠b is 10-45°. The reasons for this design are: 1. The larger the angle, the easier it is to deform; 2. It facilitates the preparation and use of the zigzag-shaped solder strip 6.
[0026] In this embodiment, ∠a = ∠b, and the lengths of the first and last segments 7 are half the length of the middle segment 8. This arrangement results in better symmetry and more uniform stress.
[0027] like Figure 2 As shown, solder strip 6 is located above the main grid and is connected and fixed to the main grid by high-temperature welding. In the top-view projection, solder strip 6 coincides with the main grid.
[0028] If the solder strip 6 is located in the outer region of E and S and extends in the direction of the first and last segments 7, its position is difficult to match with the output circuit, making the connection difficult. Therefore, the solder strip 6 is located in the outer region of E and S and is perpendicular to the fine gate.
[0029] The zigzag arrangement of the main grid allows the stress F generated at the weld between the main grid and the solder strip 6 to be decomposed into Fx towards the fine grid direction and Fy towards the main grid direction. Since both Fx and Fy are smaller than F, the warpage of the solar cell can be greatly reduced, thus improving the welding quality. Figure 3 As shown, four points are selected: F1, F2, F3, and F4. F1 can be decomposed into F1x and F1y, F2 into F2x and F2y, F3 into F3x and F3y, and F4 into F4x and F4y. This decomposition of stress can reduce the warping amplitude. Figure 3As shown, it is a structural schematic view of the traditional solder strip 6 and the main grid, wherein the solder strip 6 and the main grid are both in a straight line type, and two points are taken, which are F1 and F2 respectively, the directions of F1 and F2 are consistent with the direction of the solder strip 6, the stress is relatively concentrated, and therefore the warping amplitude is large.
[0030] With the above ideal embodiments according to the utility model as the inspiration, through the above description, the relevant staff can certainly make various changes and modifications without deviating from the technical idea of the utility model. The technical scope of the utility model is not limited to the content in the specification, and the technical scope must be determined according to the scope of claims.
Claims
1. A back contact photovoltaic module against warping, comprising a substrate (1), the back side of the substrate (1) is provided with vertical main grids and fine grids, the fine grids are composed of positive fine grids (2) and negative fine grids (3) arranged alternately and spaced, the main grids are composed of positive main grids (4) and negative main grids (5) arranged alternately and spaced; characterized in that: the main grids are in folded wave shape; a solder strip (6) is above the main grids, the solder strip (6) coincides with the main grids in plan view. The positive fine grids (2) are broken at the position of the negative main grids (5) so as not to contact the negative main grids (5); the negative fine grids (3) are broken at the position of the positive main grids (4) so as not to contact the positive main grids (4). The main grid corners form obtuse angles.
2. A back contact photovoltaic module that resists warping according to claim 1, wherein: The end points of the main grids at both ends are respectively set as E and S, and the line segments between E, S and their adjacent corner points are set as head and tail segments (7); 3. A back contact photovoltaic module that resists warping according to claim 1, wherein: A plurality of intermediate segments (8) are set between the head and tail segments (7); 4. A back contact photovoltaic module that resists warping according to claim 1, wherein: The center line of the main grid in the width direction is set as Y; The included angle between the head and tail segments (7) and Y is set as ∠a; The included angle between the intermediate segments (8) and Y is ∠b; The range of ∠a, ∠b is 10-45°. ∠a = ∠b. The length of the head and tail segments (7) is half of the length of the intermediate segments (8).
5. A back contact photovoltaic module that resists warping according to claim 4, wherein: The solder strip (6) is perpendicular to the fine grids in the outer region of E and S.
6. A back contact photovoltaic module that resists warping according to claim 5, wherein: 7. A back contact photovoltaic assembly that resists warping according to claim 4, wherein: