Solar cell grid line structure

Abstract

The utility model relates to the technical field of solar cells, and discloses a solar cell grid line structure which comprises a main grid, fine grids connected with the main grid are symmetrically arranged on two sides of the main grid, each fine grid comprises a collecting portion and a connecting portion, the width of each collecting portion is d, the width of each connecting portion is larger than that of each collecting portion, and the width of each connecting portion is larger than that of each collecting portion. The width of the connecting part is d-5d, and the connecting part is welded with the main grid to form a welding joint. According to the solar cell grid line structure, the connecting part is arranged, and the width of the connecting part is greater than that of the collecting part, so that the strength of the fine grid close to the connecting part is increased, the connecting part is not easy to break when the connecting part of the fine grid and the main grid are welded, and the fine grid and the main grid are kept in direct contact after the welding is finished, so that the welding quality is improved. The current transmission effect is good, the main grids are made of silver, the fine grids are made of aluminum, the good current collection efficiency can be guaranteed, and meanwhile the cost is reduced.

Description

TECHNICAL FIELD

[0001] The utility model relates to the field of solar cell, more specifically, it relates to solar cell grid line structure. BACKGROUND

[0002] The solar cell is a kind of semiconductor device that can convert light energy into electric energy, and the surface of cell sheet is usually distributed with fine grid and main grid, the fine grid is responsible for collecting the current on the surface of cell sheet, and the main grid is responsible for converging the current of fine grid, and then the current is delivered to external load circuit through the solder strip welded on the main grid, the fine grid and the main grid are usually formed by silk screen printing, then the connecting part of fine grid and main grid is welded to ensure the mechanical strength of the connecting part of fine grid and main grid, so that the connection between fine grid and main grid is more firm, and the long-term current transmission requirement is guaranteed.

[0003] The existing fine grid line is thin, and when the connecting part of fine grid and main grid is welded, the fine grid close to the connecting part is prone to breakage, even if the broken part of fine grid and main grid is welded together, since the broken part does not directly contact, the current transmission will be affected, thereby reducing the performance of photovoltaic module. UTILITY MODEL CONTENTS

[0004] The utility model aims at overcoming the defects in prior art, and provides a solar cell grid line structure, which can prevent the fine grid close to the connecting part from breaking when the connecting part of fine grid and main grid is welded.

[0005] To achieve the above-mentioned purpose, the utility model provides a solar cell grid line structure, which comprises: a main grid, fine grids symmetrically arranged on both sides of the main grid and connected thereto, the fine grid comprising a collecting part and a connecting part, one end of the connecting part being connected to the collecting part, the other end of the connecting part being connected to the main grid, the width of the collecting part being d, the width of the connecting part being greater than the width of the collecting part, and the width of the connecting part being d-5d, and the connecting part being welded to the main grid to form a welded joint.

[0006] By using the solar cell grid line structure, the connecting part is arranged, and the width of the connecting part is greater than the width of the collecting part, so as to increase the strength of the fine grid close to the connecting part, the connecting part of the fine grid is not prone to breaking when welded to the main grid, and the fine grid and the main grid remain in direct contact after welding, so that the current transmission effect is good.

[0007] Preferably, the material of the fine grid is aluminum, and the material of the main grid is silver. Such design can ensure good current collection efficiency and reduce cost.

[0008] As preferred, the material of the welding joint is low-temperature solder. Such design is favorable to improve the quality and reliability of the welding of the fine grid and the main grid.

[0009] As preferred, the thickness of the fine grid is consistent with that of the main grid. Such design is favorable to the formation of the fine grid and the main grid and guarantees the quality of the formed fine grid and main grid.

[0010] As preferred, a groove is arranged on the side of the connecting part close to the main grid. Such design is favorable to increase the connecting strength of the connecting part and the main grid.

[0011] As preferred, the planar shape of the connecting part is trapezoidal, and the width of the end of the connecting part close to the collecting part is d. Such design is favorable to the smooth transition of the connecting part and the collecting part, effectively reducing the contact resistance between the connecting part and the collecting part, thereby reducing the loss of current in the transmission process.

[0012] As preferred, the connecting part comprises a trapezoidal segment and a rectangular segment arranged in sequence in the direction close to the main grid, the width of the end of the trapezoidal segment close to the collecting part is d, and the width of the end of the trapezoidal segment away from the collecting part is consistent with the width of the rectangular segment. Such design is favorable to reduce the loss of current in the transmission process and save cost.

[0013] As preferred, a solder strip is further arranged, the solder strip is welded on the main grid, the width of the solder strip is slightly larger than the width of the main grid, and the solder strip forms a welding layer between the main grid and the solder strip after welding. Such design is favorable to cover the top surface of the main grid with the solder strip, thereby quickly transporting the current converged on the main grid to the external load circuit, and the solder strip is not in direct contact with the fine grid, which is favorable to the uniform flow of current through all the main grids to the battery piece, thereby guaranteeing the current collection efficiency of the battery piece.

[0014] As preferred, the material of the welding layer is tin alloy. Such design can ensure the reliable connection of the solder strip and the main grid.

[0015] The solar cell grid line structure has the advantages that:

[0016] The solar cell grid line structure has the advantages that: BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1is a schematic diagram of an overall structure of a solar cell grid line structure;

[0018] Figure 2 is a schematic diagram of a top view of a solar cell grid line structure;

[0019] Figure 3 is a schematic diagram of a top view of a main grid and a fine grid in Example 4;

[0020] Figure 4 is a schematic diagram of a top view of a main grid, a fine grid and a solder joint in Example 4;

[0021] Figure 5 is a schematic diagram of a top view of a main grid and a fine grid in Example 3;

[0022] Figure 6 is a schematic diagram of a top view of a main grid, a fine grid and a solder joint in Example 3;

[0023] Figure 7 is Figure 3 is an enlarged view of the structure at A in FIG. 1;

[0024] Figure 8 is Figure 5 is an enlarged view of the structure at B in FIG. 1;

[0025] Figure 9 is a schematic diagram of a side view of a solar cell grid line structure;

[0026] Figure 10 is Figure 9 is an enlarged view of the structure at C in FIG. 1.

[0027] In the drawings:

[0028] 1, main grid; 2, fine grid; 3, collection portion; 4, connection portion; 5, solder joint; 6, groove; 7, trapezoidal section; 8, rectangular section; 9, solder strip; 10, solder layer. DETAILED DESCRIPTION

[0029] The subject matter described herein will now be discussed with reference to example implementations. It should be understood that the discussion of these implementations is meant to enable those skilled in the art to better understand and thus, be able to

[0030] For better understanding of the present application, the following will be described in detail Figures 1-10 The solar cell grid line structure of the present application will be described in detail.

[0031] Example 1:

[0032] As Figures 1-6 shown, the solar cell grid line structure comprises a main grid 1, two symmetrical fine grids 2 connected to the main grid 1 are arranged on both sides of the main grid 1, the fine grid 2 comprises a collecting part 3 and a connecting part 4, one end of the connecting part 4 is connected to the collecting part 3, the other end of the connecting part 4 is connected to the main grid 1, the width of the collecting part 3 is d (the meaning of d is one unit length), the width of the connecting part 4 is greater than the width of the collecting part 3, and the width of the connecting part 4 is d-5d (referring to one unit length to five unit lengths), and the connecting part 4 is welded with the main grid 1 to form a welded joint 5.

[0033] It should be noted that the width of the collecting part 3 refers to the size of the collecting part 3 along the length direction of the main grid 1, the width of the connecting part 4 refers to the size of the connecting part 4 along the length direction of the main grid 1, and the area where the connecting part 4 contacts the main grid 1 is the connecting part of the main grid 1 and the fine grid 2;

[0034] Although screen printing can accurately form the patterns of the fine grid 2 and the main grid 1, the connection between the printed fine grid 2 and the main grid 1 is not firm enough to meet the requirements of long-term current transmission, and after the main grid 1 and the fine grid 2 are printed on the cell sheet through the screen printing technology, the connecting part of the main grid 1 and the fine grid 2 is welded to firmly connect the connecting part of the fine grid 2 and the main grid 1 together to form a reliable electrical connection, so as to ensure that the current can be smoothly transmitted from the fine grid 2 to the main grid 1, and a first solder is used during welding, the first solder completely covers the connecting part after being melted, and the first solder forms the welded joint 5 after being cooled.

[0035] In the embodiment, one welded joint 5 connects two symmetrical fine grids 2 and the main grid 1 to form an integral whole.

[0036] By using the solar cell grid line structure of the utility model, by arranging the connecting part 4 and the width of the connecting part 4 being greater than the width of the collecting part 3, the strength of the fine grid 2 close to the connecting part is increased, the connecting part 4 is not easy to break during the welding process of the connecting part 4 of the fine grid 2 and the main grid 1, and the fine grid 2 and the main grid 1 keep direct contact after the welding is completed, so that the current transmission effect is good.

[0037] Embodiment 2:

[0038] As an optimization of embodiment 1, as shown in Figure 7 and Figure 8 shown, the material of the fine grid 2 is aluminum, the material of the main grid 1 is silver, the material of the welded joint 5 is low-temperature solder, the thickness of the fine grid 2 and the main grid 1 is consistent, and the connecting part 4 is provided with a groove 6 close to the side of the main grid 1.

[0039] It should be noted that the silver material used in the main grid 1 can ensure good current collection efficiency, and the aluminum material used in the fine grid 2 can reduce the cost while ensuring certain current transmission capacity; the low-temperature solder refers to a solder with a melting point below 450°C, and the melting points of silver and aluminum are both higher than 600°C, which will not cause damage to the main grid 1 and the fine grid 2 during welding, and a good welding joint 5 can be formed after welding;

[0040] By arranging the groove 6, the material usage of the connecting part 4 can be reduced, and the first solder is filled into the groove 6, which can increase the contact area of the first solder with the connecting part 4 and the main grid 1, thereby increasing the connection strength of the connecting part 4 and the main grid 1.

[0041] The main grid 1 and the fine grid 2 are printed by two times of screen printing respectively, and the thicknesses of the fine grid 2 and the main grid 1 are consistent. In the second time of screen printing, the doctor blade of the screen printing device will not be affected by the main grid 1 (or the fine grid 2) printed in the first time, thereby ensuring that the quality of the fine grid 2 and the main grid 1 formed is good;

[0042] In the embodiment, the first solder is made of tin-silver-bismuth alloy, so that the welding joint 5 formed can be tightly connected with the silver main grid 1 and the aluminum fine grid 2, and the first solder can be welded at a relatively low peak temperature, which is beneficial to reduce the influence of thermal stress on the welding joint 5 and improve the welding quality and reliability;

[0043] The silver main grid 1 is first printed by the screen printing technology, and then the aluminum fine grid 2 is printed by the screen printing technology, and the thicknesses of the fine grid 2 and the main grid 1 are both 0.1 mm.

[0044] Embodiment 3:

[0045] As an optimization of embodiment 2, as shown in Figure 5 and Figure 6 The planar shape of the connecting part 4 is a trapezoid, and the width of the connecting part 4 near the collecting part 3 is d.

[0046] It should be noted that the width of the connecting part 4 near the collecting part 3 is consistent with the width of the collecting part 3, and the connecting part 4 and the collecting part 3 are smoothly connected, which can effectively reduce the contact resistance between the connecting part 4 and the collecting part 3, ensure that the current can be transmitted from the collecting part 3 to the main grid 1 along the optimal path, reduce unnecessary current dispersion and loss, and thereby reduce the loss of current in the transmission process.

[0047] In the embodiment, the width of the collecting part 3 is 0.1 mm (d), the width of the connecting part 4 near the collecting part 3 is 0.1 mm, and the width of the connecting part 4 near the main grid 1 is 0.5 mm (5d).

[0048] Embodiment 4:

[0049] As an optimization of embodiment 2, as shown in Figure 3 and Figure 4 The connecting part 4 includes a trapezoidal section 7 and a rectangular section 8 arranged in sequence along the direction close to the main grid 1, the width of the trapezoidal section 7 close to one end of the collecting part 3 is d, and the width of the trapezoidal section 7 away from one end of the collecting part 3 is consistent with the width of the rectangular section 8.

[0050] It should be noted that the width of the trapezoidal section 7 close to one end of the collecting part 3 is consistent with the width of the collecting part 3, the width of the trapezoidal section 7 away from one end of the collecting part 3 is consistent with the width of the rectangular section 8, and the collecting part 3 and the trapezoidal section 7 and the trapezoidal section 7 and the rectangular section 8 are all smoothly transitioned, which is beneficial to reduce the loss of current in the transmission process, and by setting the rectangular section 8 instead of the trapezoidal section 7 extending to the main grid 1 and the main grid 1, the material usage of the connecting part 4 can be reduced, which is beneficial to save costs.

[0051] In this embodiment, the width of the collecting part 3 is 0.1mm (d), the width of the rectangular section 8 is 0.3mm (3d), the width of the trapezoidal section 7 close to one end of the collecting part 3 is 0.1mm (d), the width of the trapezoidal section 7 close to the rectangular section 8 is 0.3mm (3d), and the groove 6 is arranged on the side of the rectangular section 8 close to the main grid 1.

[0052] Embodiment 5:

[0053] As an optimization of embodiment 3 or embodiment 4, as shown in Figure 1 , Figure 2 , Figure 9 and Figure 10 It also includes a solder strip 9, the solder strip 9 is welded on the main grid 1, and the width of the solder strip 9 is slightly larger than the width of the main grid 1, and the solder strip 9 forms a welding layer 10 between the main grid 1 and the solder strip 9 after welding, and the material of the welding layer 10 is tin alloy.

[0054] It should be noted that the second solder is used when the solder strip 9 is welded, and the second solder covers the upper surface of the main grid 1 and part of the upper surface of the solder joint 5 after melting, so that the solder strip 9 has a good welding interface, and the second solder forms a welding layer 10 after cooling;

[0055] The solder strip 9 is a copper strip with a tin-plated surface, and the material of the second solder is tin alloy, which has excellent wire performance and helps to reduce the resistance loss of the welding layer 10, thereby improving the current transmission efficiency and power generation efficiency of the photovoltaic module, and the tin alloy solder has good welding performance and is easy to form a good metallurgical bond with the silver main grid 1, in the welding process, the tin alloy solder can quickly wet and diffuse to the surface of the silver main grid 1 to form a firm welding layer 10, ensuring reliable connection of the solder strip 9 and the main grid 1, and improving the mechanical strength and durability of the photovoltaic module;

[0056] After the welding of the welding strip 9, the bottom surface height of the welding is higher than the top surface height of the fine grid 2, the welding strip 9 will not be in direct contact with the fine grid 2, and the transmission of the current can be guaranteed not to be affected. If the welding strip 9 is in direct contact with the fine grid 2, then the welding strip 9 will be in direct contact with the main grid 1 and the fine grid 2 at the same time, and an additional circuit loop will be formed, which will bypass part of the main grid 1, causing the current to not flow out of the battery piece evenly through all the main grid 1, thereby affecting the current collection efficiency of the battery piece, and further reducing the overall performance of the photovoltaic module.

[0057] In the embodiment, the width of the main grid 1 is 1.3 mm, and the width of the welding strip 9 is 1.7 mm.

[0058] The above describes the embodiments of the utility model in combination with the drawings, but the embodiments are not limited to the specific implementation described above, and the specific implementation described above is only illustrative but not restrictive. Those skilled in the art can make many forms under the inspiration of the embodiments without departing from the scope of the embodiments and the scope protected by the claims.

Claims

1. A solar cell grid line structure, characterized by, The utility model relates to a grid, which comprises: a main grid (1) having two sides symmetrically provided with thin grids (2) connected thereto, the thin grid (2) comprising a collecting part (3) and a connecting part (4), one end of the connecting part (4) being connected to the collecting part (3), the other end of the connecting part (4) being connected to the main grid (1), the width of the collecting part (3) being d, the width of the connecting part (4) being greater than that of the collecting part (3), and the width of the connecting part (4) being d-5d, the connecting part (4) being welded to the main grid (1) to form a welded joint (5), and the connecting part (4) being provided with a groove (6) near one side of the main grid (1); the connecting part (4) comprising a trapezoidal section (7) and a rectangular section (8) arranged in sequence in the direction close to the main grid (1), the width of one end of the trapezoidal section (7) close to the collecting part (3) being d, and the width of the other end of the trapezoidal section (7) away from the collecting part (3) being consistent with that of the rectangular section (8).

2. The solar cell grid line structure according to claim 1, wherein The material of the thin grid (2) is aluminum, and the material of the main grid (1) is silver.

3. The solar cell grid line structure according to claim 2, wherein The material of the welded joint (5) is low-temperature solder.

4. The solar cell grid line structure according to claim 3, wherein The thickness of the thin grid (2) is consistent with that of the main grid (1).

5. The solar cell grid line structure according to claim 1, wherein The utility model further comprises a solder strip (9) welded on the main grid (1), the width of the solder strip (9) being slightly greater than that of the main grid (1), and the solder strip (9) forming a solder layer (10) between the main grid (1) and the solder strip (9) after being welded.

6. The solar cell grid line structure according to claim 5, wherein, The material of the solder layer (10) is tin alloy.

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