An interconnection grid line and manufacturing method, applicable solar cell and interconnection method

Abstract

The present invention discloses an interconnection grid line and a manufacturing method, and an applicable solar cell and interconnection method, comprising a metal grid line frame arranged between the regions where two adjacent cells are stacked, wherein the metal grid line frame comprises a main frame vertically connected to the metal sub-grid electrodes of the parallel cells, a longitudinal sub-frame parallel to the main frame and not connected to the sub-grid electrodes of the cells, and a transverse sub-frame located on both sides and connected to the main frame and the longitudinal sub-frame. Afterwards, the front side of a solar cell and the back side of another solar cell are connected by a conductive glue filled in a rectangular frame formed by the metal grid line to form an interconnected solar cell. The manufactured metal grid line frame has a certain blocking effect on the conductive glue, and when the cells are overlapped, the conductive glue can be prevented or reduced from overflowing, thereby avoiding the formation of a series resistance and causing a short circuit of the cells.

Description

Technical Field

[0001] The invention belongs to the field of solar energy manufacturing, and specifically relates to an interconnection grid line and a manufacturing method, and applicable solar cells and an interconnection method. Background Art

[0002] In recent years, photovoltaic new energy has occupied an increasingly important position in the world's energy structure. This is actually largely due to its role in environmental protection and its gradual development under the policy support of various governments. However, if photovoltaic new energy is to be sufficiently competitive in a free market environment, or even to be on par with traditional fossil energy in the energy structure, it still requires the continuous efforts of major photovoltaic companies and research institutions to increase photovoltaic power generation efficiency and reduce power generation costs. The research and development of both photovoltaic module technology and photovoltaic cell technology can play a vital role in improving photovoltaic competitiveness, and the benefits brought by the two can even be superimposed on each other to form a greater advantage.

[0003] In recent years, a high-efficiency cell interconnection module technology has gradually emerged. This technology generally involves cutting solar cells into slices and stacking the slices along one side. The photovoltaic modules formed by this cell interconnection technology have smaller series resistance and can also reduce the hot plate effect. At the same time, the output power per unit area of ​​the module is higher, so that the photovoltaic system using this module can reduce the floor space, reduce the BOS cost and the installation and maintenance costs of the system.

[0004] The existing solution of the above-mentioned battery cell interconnection technology generally forms a main electrode on one side of the front side of the battery cell and the other side of the back side, and uses conductive glue to overlap the back main electrode of one battery cell with the front main electrode of another battery cell and apply pressure to ensure that the two batteries can form a good connection force and conductive contact. Figure 6 As shown, a main electrode 630 with a certain width is made on the solar cell 610 using screen-printed silver paste in the interconnection area of ​​the cell 610 for current collection and forming a good conductive contact with the conductive glue. Generally, a main electrode 630 is formed on one side of the front side and the other side of the back side of the cell 610, and the back main electrode of one cell is overlapped with the front main electrode of another cell using conductive glue 640, as shown in FIG. Figure 6 However, after applying pressure between the battery cells, this solution easily causes the conductive glue 640 to overflow to the side of the battery cell to form a parallel resistance and reduce the battery output power or even cause the battery cell to short-circuit, as shown in FIG. Figure 6 As shown in c.

[0005] In addition, in the prior art, the main electrode is used for current collection and forming a good conductive contact with the conductive glue, and is generally made of screen-printed silver paste, which is relatively expensive. Summary of the invention

[0006] In view of the above problems, the present invention provides an interconnection grid line and a manufacturing method, and applicable solar cells and interconnection methods.

[0007] To achieve the above technical objectives and the above technical effects, the present invention is implemented through the following technical solutions:

[0008] A plated metal grid line for the interconnection area of ​​a solar cell, the solar cell comprising a plurality of cells stacked and connected together at the edge positions, the cell edge on the cell for stacking and the extension direction of the metal secondary grid electrode on the cell are perpendicular to each other, a metal grid line frame is arranged between the areas where two adjacent cells are stacked, the metal grid line frame comprises a main frame vertically connected to the parallel metal secondary grid electrodes of the cell, a longitudinal secondary frame parallel to the main frame and not connected to the secondary grid electrodes of the cell, and a transverse secondary frame located on both sides and connected to the main frame and the longitudinal secondary frame.

[0009] As a further improvement of the present invention, the width of the main frame is 50-300um, the width of the longitudinal sub-frame or the transverse sub-frame is 12-300um, and the height is 2-20um; the length of the transverse sub-frame is 0.5-3mm, preferably 1mm. The length of the main frame or the longitudinal sub-frame is slightly smaller than the side length of the parallel battery cell.

[0010] As a further improvement of the present invention, the metal grid frames are arranged on the front and back sides of the battery cell, and the metal grid frames arranged on the front and back sides of the battery cell are respectively located on both sides of the battery cell.

[0011] As a further improvement of the present invention, the main frame is in a grid-like form composed of a plurality of intersecting fine grid lines, and the width of the fine grid lines is 15-45 um.

[0012] As a further improvement of the present invention, it also includes a graphic structure metal layer deposited inside the metal grid frame, the graphic structure metal layer includes a plurality of graphic structure splits arranged at equal distances along the extension direction of the main frame, one end of the graphic structure split is connected to the main frame, and the other end is located inside the metal grid frame, and the distance between the two ends is greater than 1 / 2 of the horizontal secondary frame.

[0013] As a further improvement of the present invention, a plurality of metal grid frames are included, wherein the metal grid frames are arranged along the length of the battery side for stacking, and the lateral sub-frames in adjacent metal grid frames can be connected by a second main frame located therebetween.

[0014] As a further improvement of the present invention, the second main border is in a grid-like form composed of a plurality of mutually perpendicular thin grid lines, and the width of the thin grid lines is 15-45 um.

[0015] A method for producing the above-mentioned electroplated metal grid lines for the interconnection area of ​​a solar cell, comprising producing a patterned mask on the surface of the cell and producing a conductive layer of the metal grid line frame by electroplating deposition; and also including or excluding the use of chemical plating or electroplating to deposit either or both of a seed layer and a protective layer.

[0016] Furthermore, the metal grid frame and the metal electrodes on the battery cell are manufactured at the same time.

[0017] A solar cell with interconnected regions manufactured using the above manufacturing method.

[0018] A method for interconnecting solar cells is used to connect at least two solar cells, and connect the front side of one solar cell and the back side of another solar cell through conductive glue filled in a metal grid frame formed by metal grids.

[0019] Beneficial effects of the present invention:

[0020] 1. The patterned grid line of the present invention is a metal grid line frame structure that can form a certain barrier effect on the conductive glue. When the battery cells are overlapped, it can prevent or reduce the overflow of the conductive glue and avoid the formation of series resistance to cause a short circuit in the battery cells.

[0021] 2. The metal grid wire frame can not only assist in the current collection during the operation of the battery cell, but also balance the uneven current derived from the metal auxiliary grid wire. Furthermore, due to the poor lateral conductivity of the conductive adhesive layer, in order to reduce the series resistance, the present invention increases the conductivity of the lateral current transport by forming a graphic structure metal layer in the metal grid wire frame, thereby improving the battery performance.

[0022] 3. In the solution of the present invention, conductive glue is filled in multiple metal grid frames distributed along the battery edge where the battery stacking area is located to interconnect the battery cells, and adjacent metal grid frames are connected using thicker main frames or metal grid-like grids, which can save the amount of conductive glue without reducing the reliability of the battery.

[0023] 4. The method of the present invention uses a patterned grid line formed by electroplating technology to replace the main electrode formed by screen-printed silver paste, which can save the cost of silver paste. Furthermore, in the electroplating technology, cheaper metals such as copper, tin, and nickel can be used to replace silver, further saving costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 (a) is a schematic diagram of the metal gate line structure of the interconnection region according to the first embodiment of the present invention, Figure 1(b) is a schematic diagram of the structure of a solar cell in an interconnected area made using the method of the present invention, Figure 1 (c) is a schematic diagram of the structure of the interconnected solar cells of the present invention after pressure is applied;

[0025] Figure 2 A schematic diagram of a metal gate line structure in an interconnection region according to a second embodiment of the present invention;

[0026] Figure 3 A schematic diagram of a metal gate line structure in an interconnection region according to a third embodiment of the present invention;

[0027] Figure 4 A schematic diagram of a metal gate line structure in an interconnection region according to a fourth embodiment of the present invention;

[0028] Figure 5 A schematic diagram of a metal gate line structure in an interconnection region according to a fifth embodiment of the present invention;

[0029] Figure 6 (a) is a schematic diagram of the structure of a solar cell in the interconnection area made by the prior art. Figure 6 (b) Figure 6 (a) Schematic diagram of the enlarged structure at the overlap of the battery cells. Figure 6 (c) is a schematic diagram of the enlarged structure of the interconnected solar cells of the prior art after pressure is applied. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0031] The application principle of the present invention is described in detail below in conjunction with the accompanying drawings.

[0032] Example 1

[0033] like Figure 1 As shown in a, the left side is a schematic diagram of the battery cell, and the right side is a schematic diagram of the electroplated grid line structure after the interconnection area is enlarged.

[0034] In this embodiment, the electroplated grid line includes a metal grid line frame 130 made in the area where the solar cells are interconnected at the boundary of the long sides of the solar cell 110. It includes a main frame 131 parallel to the long side of the cell and connected to one end of the metal sub-grid electrode 120 on the cell, two horizontal sub-frames 132 and a vertical sub-frame 133. The main frame 131 is about 2-20μm high, preferably 5-12μm, and 12-300μm wide, preferably 80-300μm. The three sub-frames 132 and 133 are about 2-20μm high, preferably 5-12μm, and 12-300μm wide, preferably 12-45μm here. The length of the horizontal sub-frame 132 is about 0.5-3mm, preferably, about 1mm.

[0035] The electroplated grid lines are made at the same time as the metallized electrodes of the battery. The production method includes making a patterned mask on the battery surface, and using electroplating deposition to make the conductive layer in the grid lines, and may or may not use chemical plating or electroplating to deposit either or both of a seed layer or a protective layer, and finally removing the mask.

[0036] The three solar cells 110a-110c in the interconnection area made by this method are overlapped with each other using conductive glue, and their interfaces are as follows: Figure 1 In some embodiments, the solar cells 110a-110c are bifacial cells, and the metal grid frame 130 is fabricated on the opposite side regions of the front and back sides of the solar cell 110b, that is, fabricated on the front side of the solar cell 110b in the region connected to the cell 110c arranged above the cell, and fabricated on the back side of the solar cell 110b in the region connected to the cell 110a arranged below the cell.

[0037] Using this patent solution, after applying pressure between the cells, as shown in 1c, the frame of the metal grid frame 130 can form a certain barrier effect on the conductive glue 140, preventing or reducing the overflow of the conductive glue 140, and avoiding the formation of series resistance and causing the cell short circuit. At the same time, compared with the screen-printed silver paste main electrode, the patterned metal grid line formed by electroplating technology in this solution can use cheaper metals (such as copper, tin, nickel, etc.) instead of expensive silver paste, reducing battery costs.

[0038] Example 2

[0039] like Figure 2 As shown, the left side is a schematic diagram of the battery cell, and the right side is a schematic diagram of the electroplated grid line structure after the interconnection area is enlarged.

[0040] In this embodiment, the electroplated grid line includes a metal grid line frame 230 manufactured in the region where the solar cells are interconnected at the boundary of the long side of the solar cell 210 .

[0041] In this embodiment, the main frame 231 and the secondary frame 232 have the same width, preferably 80-200 μm, and the frame height is about 2-20 μm, preferably 5-12 μm. The length of the lateral secondary frame 132 is about 0.5-3 mm, preferably about 1 mm. The beneficial effect of using a wider secondary frame is that the charge is transferred through the surrounding frames instead of only through the main frame and the conductive glue, which reduces the series resistance and the metal grid frame 230 still has a good current balancing effect when the main frame is broken.

[0042] In this embodiment, there is also a graphic structure metal layer 233 inside the metal grid frame 230, which is preferably a plurality of triangular grid lines as shown in the figure, whose wide end is connected to the main frame 231, and whose length along the narrow side of the battery cell is preferably greater than half the length of the lateral secondary frame 232. Generally speaking, the lateral conductivity of the conductive adhesive layer (or the conductive adhesive layer superimposed on the TCO layer) is poor. The use of the graphic structure metal layer 233 in the metal grid frame in this embodiment can increase the conductivity of the lateral transport of the current, reduce the series resistance, and improve the battery performance.

[0043] The metal grid wire frame 230 and the patterned metal layer 233 therein are manufactured simultaneously with the metallized electrodes of the cell. In this embodiment, the manufacturing method includes manufacturing a patterned mask on the cell surface, depositing a nickel seed layer in the grid wire by chemical plating, manufacturing a copper conductive layer by electroplating deposition, and finally removing the mask.

[0044] Example 3

[0045] like Figure 3 As shown, the left side is a schematic diagram of the battery cell, and the right side is a schematic diagram of the electroplated grid line structure after the interconnection area is enlarged.

[0046] In this embodiment, the electroplated grid line includes a metal grid line frame 330 manufactured in the region where the solar cells are interconnected at the boundary of the long side of the solar cell 310 .

[0047] In this embodiment, the width of the secondary frame 332 is 12-300 μm, preferably 12-45 μm, and the height is about 2-20 μm, preferably 5-12 μm. The main frame 331 is a grid-like fine grid, and the width of each fine grid line is preferably about 15-45 μm. Using a grid-like fine grid as the main frame 331 can reduce the maximum width of the electroplated grid line, ensuring that the electroplated grid line has sufficient adhesion.

[0048] In this embodiment, a pattern structure metal layer 333 is further provided inside the metal grid wire frame 330 . In this embodiment, the pattern structure metal layer 333 inside is an extension of the lateral fine grid of the main frame 331 .

[0049] The metal grid wire frame 330 and the patterned metal layer 333 therein are manufactured simultaneously with the metallized electrodes of the cell. In this embodiment, the manufacturing method includes manufacturing a patterned mask on the cell surface, depositing the copper conductive layer and tin protective layer in the grid wire by electroplating, and finally removing the mask.

[0050] Example 4

[0051] like Figure 4 As shown, the left side is a schematic diagram of the battery cell, and the right side is a schematic diagram of the electroplated grid line structure after the interconnection area is enlarged.

[0052] In this embodiment, the electroplated grid line includes a grid line main frame 431 made in the area where the cells are interconnected at the long side boundary of the solar cell 410 and a plurality of metal rectangular frames 430 arranged along the main frame 431. The length of each metal rectangular frame 430 is about 5-50mm, preferably 10-30mm here. The spacing between adjacent metal frames is about 3-30mm, preferably 5-20mm here. The secondary frames between adjacent metal frames are connected by the second main frame 431b, so that the width of the main frame 431 within the rectangular frame range (segment 431a) is relatively small, preferably 50-80μm, and the width within the interval area of ​​the rectangular frame 430 (segment 431b) is relatively large, preferably 80-200μm. This is because the cells are interconnected by the conductive glue in the rectangular frame 430, and in the interval area of ​​the rectangular frame 430, the current direction in the main frame 431a is perpendicular to the direction of the secondary grid 420, so using a wider main frame 431a can reduce resistance loss.

[0053] In this embodiment, a patterned structured metal layer 433 is further provided inside the metal grid frame 430 to balance the current and reduce the series resistance of the conductive adhesive layer.

[0054] The metal grid wire frame 430 and the patterned metal layer 433 therein are manufactured simultaneously with the metallized electrodes of the cell. In this embodiment, the manufacturing method includes manufacturing a patterned mask on the cell surface, depositing a nickel seed layer and a copper conductive layer in the grid wire by electroplating, manufacturing a silver protective layer by chemical plating, and finally removing the mask.

[0055] The metal grid lines in the interconnection area of ​​the battery cell made by this method can save the amount of conductive glue without reducing the performance and reliability of the battery.

[0056] Example 5

[0057] like Figure 5 As shown, the left side is a schematic diagram of the battery cell, and the right side is a schematic diagram of the electroplated grid line structure after the interconnection area is enlarged.

[0058] In the present embodiment, the electroplated grid line includes a grid line main frame 531 made in the area where the solar cells are interconnected at the long side boundary of the solar cell 510 and a plurality of metal rectangular frames 530 arranged along the main frame 531. Each metal rectangular frame 530 is about 5-50mm long, preferably 10-30mm here. The distance between adjacent metal frames is about 3-30mm, preferably 5-20mm here. The width of the main frame 531 and the secondary frame 532 of the rectangular frame 530 is preferably 80-300μm, and the height is preferably 5-12μm. Adjacent metal rectangular frames 530 are connected by a second main frame 534 composed of metal grid-like grid lines.

[0059] In this embodiment, there is a pattern structure metal layer 533 inside the metal grid frame 530 to balance the current and reduce the series resistance of the conductive adhesive layer. In this embodiment, the pattern structure metal layer 533 is a plurality of metal grid lines connecting two long sides of the rectangular frame.

[0060] The metal grid wire frame 530 and the patterned metal layer 533 therein are manufactured simultaneously with the metallized electrodes of the cell. In this embodiment, the manufacturing method includes manufacturing a patterned mask on the cell surface, depositing the copper conductive layer in the grid wire by electroplating, and finally removing the mask.

[0061] The metal grid lines in the interconnection area of ​​the battery cell made by this method can save the amount of conductive glue without reducing the performance and reliability of the battery.

[0062] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, such as changing the shape of the rectangular metal frame, etc. These changes and improvements fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A metal grid line for electroplating in the interconnection area of ​​a solar cell, wherein the solar cell comprises a plurality of cells stacked and connected together at the edge positions, wherein the cell edge for stacking on the cell and the extension direction of the metal secondary grid electrode on the cell are perpendicular to each other, and a metal grid line frame is arranged between the areas where two adjacent cells are stacked, characterized in that: The metal grid frame includes a main frame vertically connected to the parallel battery cell sub-grid, a longitudinal sub-frame parallel to the main frame and not connected to the battery cell metal sub-grid electrode, and a transverse sub-frame located on both sides connected to the main frame and the longitudinal sub-frame; the metal grid frame is arranged on the front and back of the battery cell; The metal grid frame is used to fill the conductive glue to form a barrier effect on the conductive glue.

2. The electroplated metal grid line for interconnection area of ​​solar cell according to claim 1, characterized in that: The width of the main frame is 50-300um, the width of the longitudinal sub-frame or the transverse sub-frame is 12-300um, and the height is 2-20um; the length of the transverse sub-frame is 0.5-3mm.

3. The electroplated metal grid line for interconnection area of ​​solar cell according to claim 1, characterized in that: The metal grid frames arranged on the front and back sides of the battery cell are respectively located on both sides of the battery cell.

4. The electroplated metal grid line for interconnection area of ​​solar cell according to claim 1, characterized in that: The main frame is in a grid-like form formed by a plurality of intersecting fine grid lines, and the width of the fine grid lines is 15-45um.

5. The electroplated metal grid line for interconnection area of ​​solar cell according to claim 1 or 4, characterized in that: It also includes a graphic structure metal layer deposited inside the metal grid frame, the graphic structure metal layer includes a plurality of graphic structure splits arranged at equal distances along the extension direction of the main frame, one end of the graphic structure split is connected to the main frame, and the other end is located inside the metal grid frame, and the distance between the two ends is greater than 1 / 2 of the horizontal secondary frame.

6. The electroplated metal grid line for interconnection area of ​​solar cell according to claim 1, characterized in that: It comprises a plurality of metal grid frames, which are arranged along the side length of the battery side for stacking, and the transverse sub-frames in adjacent metal grid frames are connected via a second main frame located therebetween.

7. A method for manufacturing a metal grid line electroplated for interconnection of solar cells according to any one of claims 1, 2, 3, 4, or 6, characterized in that: It includes making a graphic mask on the surface of the battery and using electroplating deposition to make a conductive layer of the metal grid frame; it also includes or does not include using chemical plating or electroplating to deposit either or both of a seed layer and a protective layer.

8. A solar cell with interconnected regions manufactured by the manufacturing method of claim 7.

9. The solar cell according to claim 8, characterized in that: The metal grid frame and the metal electrodes on the battery cell are manufactured at the same time.

10. A method for interconnecting solar cells, for connecting at least two solar cells as claimed in claim 8, characterized in that: The front side of one solar cell and the back side of another solar cell are connected to each other through the conductive glue filled in the metal grid frame formed by the metal grid.

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