Photovoltaic module and preparation method thereof

Abstract

The present application provides a photovoltaic module and a method for manufacturing the same. The photovoltaic module includes multiple battery strings, each of which is formed by multiple battery cells connected in series along a first direction. An isolation region is provided in the center of the battery cell to separate the battery cell into a first battery cell and a second battery cell. The isolation region extends along a second direction, and multiple insulating through-holes are provided in the isolation region along the second direction. The first direction intersects the second direction, and the insulating through-holes penetrate the photovoltaic module along the thickness direction of the photovoltaic module. Multiple welding ribbons are provided, each of which is connected to the first battery cell and the second battery cell. The insulating through-holes physically isolate the positive and negative electrodes of the battery cells located on both sides of the insulating through-holes, thereby ensuring that adjacent battery cells isolated by the insulating through-holes will not be short-circuited when connected in series, while also avoiding damage to the battery caused by laser scribing. This solves the problem in the prior art of failing to balance battery efficiency and manufacturing cost when welding photovoltaic modules in series.

Description

Technical Field

[0001] The present application relates to the technical field of solar cells, and in particular to a photovoltaic module and a method for preparing the same. Background Art

[0002] Traditional back-contact solar cells require the cells to be laser-cut in half before stringing together at the module end. While this cutting method allows for the serial connection of cells, it also introduces laser cutting damage, resulting in reduced module power. To address the issue of laser cutting damage, a half-cell passivation process is typically used to passivate the cut edges. However, this technology is complex and requires large-scale modifications to production equipment, including custom fixtures, quartz boats, flower baskets, and other containers, significantly increasing costs. However, if the cells are not sliced ​​and directly connected in series using solder ribbons, a short circuit will occur due to the lack of effective isolation between the positive and negative poles of the cells. Summary of the Invention

[0003] The main purpose of the present application is to provide a photovoltaic module and a preparation method thereof, so as to solve the problem in the prior art that it is impossible to balance the cell efficiency and preparation cost when string welding photovoltaic modules.

[0004] In order to achieve the above-mentioned purpose, according to one aspect of the present application, a photovoltaic module is provided, comprising: a plurality of battery strings, wherein the plurality of battery strings are formed by a plurality of battery slices connected in series in sequence along a first direction; an isolation region is arranged in the central area of ​​the battery slice to separate the battery slice into a first battery slice and a second battery slice, the isolation region extends along a second direction, and a plurality of insulating through holes are arranged in sequence in the isolation region along the second direction, the first direction intersects with the second direction, and the insulating through holes penetrate the photovoltaic module along the thickness direction of the photovoltaic module; a plurality of welding strips, wherein the welding strips are respectively connected to the first battery slice and the second battery slice.

[0005] Optionally, the photovoltaic module further includes a plurality of first main grids and a plurality of second main grids, the first main grids and the second main grids extend along the first direction, the polarities of the first main grids and the second main grids are opposite, the welding strips are respectively connected to the first main grids and the second main grids located on different battery slices, and the insulating through-holes are at least located directly below the welding strips.

[0006] Optionally, the photovoltaic module further includes a plurality of first fine grids and a plurality of second fine grids, the first fine grids and the second fine grids extend along the second direction, the first fine grids and the second fine grids have opposite polarities, the welding strips are respectively connected to the first fine grids and the second fine grids located on different battery slices, and the insulating through-holes are at least located directly below the welding strips.

[0007] Optionally, the photovoltaic assembly further includes a plurality of first connecting portions and a plurality of second connecting portions, wherein the first connecting portions are connected to the first fine grids, and the second connecting portions are connected to the second fine grids.

[0008] Optionally, the photovoltaic module further includes a plurality of first fine grids and a plurality of second fine grids, the first fine grids and the second fine grids extend along the first direction, the first fine grids and the second fine grids have opposite polarities, the welding strips are respectively connected to the first fine grids and the second fine grids located on different battery slices, and the insulating through-holes are at least located directly below the welding strips.

[0009] Optionally, the photovoltaic module further includes: a substrate having a first surface, the first surface including a first doped semiconductor layer and a second doped semiconductor layer, the first doped semiconductor layer and the second doped semiconductor layer are arranged alternately along the second direction, and the doping types of the first doped semiconductor layer and the second doped semiconductor layer are opposite.

[0010] Optionally, the first doped semiconductor layer in the first battery slice and the first doped semiconductor layer in the second battery slice are located on both sides of the isolation region in the first direction in a one-to-one correspondence, and the second doped semiconductor layer in the first battery slice and the second doped semiconductor layer in the second battery slice are located on both sides of the isolation region in the first direction in a one-to-one correspondence.

[0011] Optionally, the first doped semiconductor layer in the first battery slice and the second doped semiconductor layer in the second battery slice are located on both sides of the isolation region in the first direction in a one-to-one correspondence, and the second doped semiconductor layer in the first battery slice and the first doped semiconductor layer in the second battery slice are located on both sides of the isolation region in the first direction in a one-to-one correspondence.

[0012] Optionally, the number of the insulating through holes is 20 to 60.

[0013] Optionally, the inner diameter of the insulating through hole is 0.3 mm to 3 mm.

[0014] Optionally, the inner diameter of the insulating through hole is 0.5 mm to 1.5 mm.

[0015] Optionally, the inner diameter of the insulating through hole is 0.02 mm to 0.5 mm.

[0016] In order to achieve the above-mentioned purpose, according to another aspect of the present application, a method for preparing a photovoltaic module is provided, and the preparation method is used to prepare the photovoltaic module, comprising: forming a plurality of battery strings, wherein the plurality of battery strings are formed by a plurality of battery slices connected in series in a first direction; forming an isolation area in the central area of ​​the battery slice to separate the battery slice into a first battery slice and a second battery slice, wherein the isolation area extends along a second direction, and the isolation area is provided with a plurality of insulating through holes in sequence along the second direction, wherein the first direction intersects with the second direction, and the insulating through holes penetrate the photovoltaic module along the thickness direction of the photovoltaic module; and providing a plurality of welding strips, wherein the welding strips are respectively connected to the first battery slice and the second battery slice.

[0017] Optionally, after the step of forming the isolation area, the preparation method further includes: forming a passivation layer on at least part of the first surface and the second surface of the substrate of the battery cell and the side wall of the insulating through hole, the first surface and the second surface being opposite surfaces of the substrate; and performing a texturing treatment on the passivation layer located on the second surface.

[0018] Optionally, after the step of performing texturing treatment on the passivation layer located on the second surface, the preparation method further includes: providing a plurality of welding strips, and electrically connecting the plurality of welding strips to the first doped semiconductor layer of the first battery slice and the second doped semiconductor layer of the second battery slice, respectively, the first battery slice and the second battery slice are adjacent battery slices, and the first doped semiconductor layer and the second doped semiconductor layer are both located on the first surface.

[0019] Applying the technical solution of this application, a photovoltaic module includes multiple cell strings formed by multiple cells connected in series along a first direction. An isolation region is provided in the center of the cell to separate the cell into a first cell segment and a second cell segment. The isolation region extends along a second direction and includes multiple insulating through-holes sequentially provided in the isolation region along the second direction. The first and second directions intersect, and the insulating through-holes extend through the thickness of the photovoltaic module. The module also includes multiple welding ribbons, each connected to the first cell segment and the second cell segment. By providing multiple insulating through-holes in the isolation region, where the cell would otherwise be laser-scribed, the insulating through-holes physically isolate the positive and negative electrodes of the cell located on either side of the insulating through-holes, preventing electrons and holes on at least two sides of the insulating through-holes from meeting and thereby recombination. This reduces energy loss caused by recombination of photogenerated carriers and improves cell efficiency. In the prior art, after the battery cell is diced, the scribed area is further passivated to ensure the insulation performance of the battery. In the present application, after the insulating through-hole is formed in the isolation area, the insulating through-hole can be passivated and polished at the same time when the battery cell is subjected to a complete polishing and passivation process, thereby reducing the cost investment in the passivation process for the edge of the dicing area, thereby solving the problem in the prior art that it is impossible to take into account both battery efficiency and preparation cost when stringing solar cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The drawings that constitute part of this application are used to provide a further understanding of this application. The illustrative embodiments of this application and their descriptions are used to explain this application and do not constitute an improper limitation on this application. In the drawings:

[0021] Figure 1 A schematic diagram of a top view of a first photovoltaic module provided according to an embodiment of the present application is shown;

[0022] Figure 2 A schematic diagram of a top view of a second photovoltaic assembly provided according to an embodiment of the present application is shown;

[0023] Figure 3 A schematic diagram of a three-dimensional structure of a photovoltaic module provided according to an embodiment of the present application is shown;

[0024] Figure 4 A schematic diagram of a top view of a third photovoltaic assembly provided according to an embodiment of the present application is shown;

[0025] Figure 5 1 shows a schematic top view of the structure of a fourth photovoltaic assembly provided according to an embodiment of the present application;

[0026] Figure 6 1 shows a schematic top view of the structure of a fifth photovoltaic assembly provided according to an embodiment of the present application;

[0027] Figure 7 A schematic diagram of a process for preparing a photovoltaic module according to an embodiment of the present application is shown;

[0028] Figure 8 1 shows a schematic cross-sectional structure diagram of a substrate after insulating through holes are formed in a method for preparing a photovoltaic module provided in an embodiment of the present application;

[0029] Figure 9 Shown in Figure 8 A schematic cross-sectional structure diagram of the substrate after a passivation layer is formed on the first doped semiconductor layer, the second doped semiconductor layer, the second surface of the substrate, and the sidewalls of the insulating through hole;

[0030] Figure 10 Shown in Figure 9 Schematic diagram of the cross-sectional structure of the substrate after the welding strip is formed on the gate line.

[0031] The above drawings include the following reference numerals:

[0032] 10. Battery cell; 11. Isolation region; 12. Insulating via; 20. Substrate; 21. First doped semiconductor layer; 22. Second doped semiconductor layer; 23. Tunneling passivation layer; 24. Passivation layer; 241. Velvet; 30. Welding strip; 40. Gate line; 51. First main grid; 52. Second main grid; 61. First connecting portion; 62. Second connecting portion. DETAILED DESCRIPTION

[0033] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present application belongs.

[0034] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0035] It should be noted that the terms "first," "second," and the like in the specification and claims of the present invention and the accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a particular order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate for the embodiments of the present invention described herein. In addition, the terms "including," "having," and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus comprising a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to these processes, methods, products, or apparatuses.

[0036] It should be understood that when an element (such as a layer, film, region, or substrate) is described as being “on” another element, the element may be directly on the other element or intervening elements may be present. Furthermore, in the specification and claims, when it is described that an element is “connected to” another element, the element may be “directly connected to” the other element or “connected to” the other element through a third element.

[0037] As introduced in the background technology, in the prior art, solar cells need to be cut into two halves by laser before being serially welded at the module end. Although this cutting method can realize the serial connection of the cell slices, it also brings about laser cutting damage, resulting in reduced module power. In order to solve the problem of laser cutting damage, a half-cell passivation process is usually used to passivate the cut edges. However, the process of this technology is complicated and requires large-scale transformation of production equipment, including customized fixtures, quartz boats, flower baskets and other containers, which greatly increases the cost. However, if the battery is not sliced ​​and directly connected in series with a welding ribbon, a short circuit will occur due to the lack of effective isolation between the positive and negative poles of the battery. In order to solve the problem of not being able to take into account both battery efficiency and preparation cost when serially welding solar cells, the embodiments of the present application provide a photovoltaic module and a preparation method thereof.

[0038] According to one aspect of this application, Figure 1 and Figure 2 As shown, a photovoltaic module is provided, comprising: a plurality of battery strings, wherein the plurality of battery strings are formed by a plurality of battery slices 10 connected in series in a first direction A; an isolation region 11 is provided in the central area of ​​the battery slice 10 to separate the battery slice 10 into a first battery slice and a second battery slice, the isolation region 11 extends along a second direction B, and a plurality of insulating through holes 12 are sequentially provided in the isolation region 11 along the second direction B, the first direction A intersects with the second direction B, and the insulating through holes 12 penetrate the photovoltaic module along a thickness direction C of the photovoltaic module; a plurality of welding ribbons 30, the welding ribbons 30 are respectively connected to the first battery slice and the second battery slice.

[0039] By setting a plurality of insulating through-holes in the isolation area where the battery cell originally needs to be laser-scribed, the insulating through-holes physically isolate the positive and negative electrodes of the battery cell located on both sides of the insulating through-holes, so that at least the electrons and holes on both sides of the insulating through-holes will not meet and recombine, thereby reducing the energy loss caused by the recombination of photogenerated carriers and improving the battery efficiency. In the prior art, after the battery cell is scribed, the scribed area will be further passivated to ensure the insulation performance of the battery. After the insulating through-holes are formed in the isolation area, the present application can simultaneously passivate and polish the insulating through-holes when the battery cell is completely polished and passivated, reducing the cost of the passivation process on the edge of the scribed area. This solves the problem in the prior art that it is impossible to take into account both battery efficiency and preparation cost when stringing solar cells.

[0040] The central area is as follows Figure 1 The entire area along the second direction B at the center of the battery cell 10 shown is not a center point area in the conventional sense. The first battery cell, the second battery cell, and the isolation region 11 constitute the battery cell 10 .

[0041] The above-mentioned battery cell can be a back-contact battery, and the preparation process of the above-mentioned insulating through-hole can be laser perforation. After the insulating through-hole is formed, the front side of the battery cell can be texturing, polishing, coating passivation and other processes. While saving the cost of the passivation process, it can also further reduce the damage to the battery caused by the formation of the insulating through-hole, thereby further reducing the loss of battery efficiency.

[0042] The ends of the aforementioned solder ribbon connect semiconductor layers of different doping types, thereby achieving a series connection between the first and second cell slices and converging the currents of the adjacent first and second cell slices. After the solder ribbon connects the first doped semiconductor layer of the first cell slice to the second doped semiconductor layer of the second cell slice (or connects the second doped semiconductor layer of the first cell slice to the first doped semiconductor layer of the second cell slice), when the solar cell is exposed to light, photon energy is absorbed and converted into electron-hole pairs (photogenerated carriers). In the silicon substrate, these carriers are separated according to the direction of the internal electric field of the cell, with electrons migrating to the n-type first doped semiconductor layer (or n-type second doped semiconductor layer) and holes migrating to the p-type second doped semiconductor layer (or p-type first doped semiconductor layer). However, in the isolation region of the cell—the area between the positive and negative electrodes not fully covered by the electric field—some photogenerated carriers (electrons and holes) may meet and recombine, resulting in energy loss. By preparing an insulating through hole in the isolation region, electrons and holes on at least two sides of the insulating through hole will not meet and recombine, thereby reducing energy loss caused by photogenerated carrier recombination and improving battery efficiency.

[0043] In practical applications, the conductive channel within the cell is not only a diffusion layer, but a composite conductive (diffusion layer + body region) method. In particular, under normal operating conditions of solar cells, the excess photogenerated carriers generated in the body region also have excellent carrier transport capabilities. In the prior art, a laser scribing process is usually used to form insulating grooves or insulating lines in the diffusion doping layer to separate the diffusion layers of the positive and negative electrodes to prevent direct electrical contact. However, the above-mentioned method of forming insulating dividing lines that separate the diffusion layers cannot achieve complete insulation. Laser scribing may leave tiny conductive paths at the edges of the grooves, which may cause leakage or short circuits under high voltages. Only physical isolation can achieve true insulation. This application proposes to form physical through-holes in the areas that need to be isolated by laser perforation technology before the cell is textured, rather than relying solely on insulating grooves formed by laser scribing. Physical through-holes can completely isolate the internal conductive paths of the positive and negative electrodes, thereby achieving a more reliable insulation effect and avoiding the problem of incomplete insulation that may be caused by laser scribing.

[0044] above Figure 1 and Figure 2 The extension direction of the battery string is the first direction A, the width direction of the battery cell is the second direction B, and the thickness direction of the battery cell is the third direction C. Figure 1 and Figure 2 The gate line is not shown in the figure, and the connection relationship between the gate line and the first doped semiconductor layer 21 and the second doped semiconductor layer 22 can be conventionally set according to the existing technology, and is not specifically limited in the embodiment of the present application. Figure 1 and Figure 2 Only the positional relationship among the first doped semiconductor layer 21 , the second doped semiconductor layer 22 , the soldering ribbon 30 and the insulating through hole 12 is shown.

[0045] In some optional embodiments, such as Figure 3As shown, a substrate 20 has a first surface comprising a first doped semiconductor layer 21 and a second doped semiconductor layer 22. The first doped semiconductor layer 21 and the second doped semiconductor layer 22 are arranged alternately along a second direction B, and have opposite doping types. The first doped semiconductor layer 21 may be a structure in a first cell slice, and the second doped semiconductor layer 22 may be a structure in a second cell slice. The insulating via 12 is located in the isolation region, and the gate line 40 is a fine gate of the cell. A tunneling passivation layer 23 is provided on the first surface of the substrate 20. The first doped semiconductor layer 21 and the second doped semiconductor layer 22 are located on the tunneling passivation layer 23. A passivation layer 24 is provided on the first doped semiconductor layer 21, the second doped semiconductor layer 22, the second surface, and the sidewalls of the insulating via 12. The passivation layer 24 on the second surface is textured to form a textured surface 241. The passivation layer 24 on the first and second surfaces can passivate the front and back surfaces of the cell, improving interface quality. The passivation layer 24 located on the sidewalls of the insulating through-hole 12 further isolates and insulates the first doped semiconductor layer 21 and the second doped semiconductor layer 22, thereby suppressing indirect carrier recombination at the interface between the first doped semiconductor layer 21 and the second doped semiconductor layer 22. This avoids the problem of reduced photocurrent in the cell due to carrier recombination, ensures the carrier concentration in the cell, and thus achieves a high photoelectric conversion efficiency of the cell. The material of the above-mentioned passivation layer 24 can be a single layer or a composite layer of aluminum oxide, silicon nitride, silicon oxide, and silicon oxynitride.

[0046] In some embodiments, the substrate may be made of an elemental semiconductor material. Elemental semiconductor materials are composed of a single element, such as silicon or germanium. The elemental semiconductor material may be in at least one of a single crystalline state, a polycrystalline state, an amorphous state, or a microcrystalline state (a state having both single crystalline and amorphous states is referred to as a microcrystalline state).

[0047] In some embodiments, the substrate may be an N-type semiconductor substrate or a P-type semiconductor substrate. The N-type semiconductor substrate is doped with an N-type doping element, which may be any of Group V elements such as phosphorus (P), bismuth (Bi), antimony (Sb), or arsenic (As). The P-type semiconductor substrate is doped with a P-type doping element, which may be any of Group III elements such as boron (B), aluminum (Al), gallium (Ga), or indium (In).

[0048] In some embodiments, the first doped semiconductor layer may be N-type doped or P-type doped, and the second doped semiconductor layer may be N-type doped or P-type doped. The doping type of the first doped semiconductor layer is opposite to the doping type of the second doped semiconductor layer, for example, the first doped semiconductor layer is N-type doped and the second doped semiconductor layer is P-type doped. The first doped semiconductor layer is P-type doped and the second doped semiconductor layer is N-type doped.

[0049] In some optional embodiments, such as Figure 1 As shown, the first doped semiconductor layer 21 in the first cell segment and the second doped semiconductor layer 22 in the second cell segment are located on both sides of the isolation region 11 in the first direction A in a one-to-one correspondence, and the second doped semiconductor layer 22 in the first cell segment and the first doped semiconductor layer 21 in the second cell segment are located on both sides of the isolation region 11 in the first direction A in a one-to-one correspondence. Figure 1 Taking the left-side cell 10 as an example, the arrangement order of the first doped semiconductor layer 21 and the second doped semiconductor layer 22 along the second direction B on the left side of the isolation region 11 is: second doped semiconductor layer 22, first doped semiconductor layer 21, second doped semiconductor layer 22, and first doped semiconductor layer 21. The arrangement order of the first doped semiconductor layer 21 and the second doped semiconductor layer 22 along the second direction B on the right side of the isolation region 11 is: first doped semiconductor layer 21, second doped semiconductor layer 22, first doped semiconductor layer 21, and second doped semiconductor layer 22. The positions of the doped regions on the left and right sides correspond one-to-one, and their arrangement order along the second direction B is opposite. When connecting the cell slices with the soldering ribbon 30, the soldering ribbon 30 can be extended along the first direction A, directly connecting to the different polarities of adjacent cell slices for current aggregation. There is no need to bend the soldering ribbon 30, which simplifies the preparation process of the soldering ribbon 30.

[0050] In some optional embodiments, such as Figure 2 As shown, the first doped semiconductor layer 21 in the first cell segment and the first doped semiconductor layer 21 in the second cell segment are located on both sides of the isolation region 11 in the first direction A in a one-to-one correspondence, and the second doped semiconductor layer 22 in the first cell segment and the second doped semiconductor layer 22 in the second cell segment are located on both sides of the isolation region 11 in the first direction A in a one-to-one correspondence. Figure 2 Taking the left cell 10 as an example, the arrangement order of the first doped semiconductor layer 21 and the second doped semiconductor layer 22 on the left and right sides of the isolation region 11 along the second direction B is: first doped semiconductor layer 21, second doped semiconductor layer 22, first doped semiconductor layer 21 and second doped semiconductor layer 22. The positions of the doped regions on the left and right sides correspond one to one, and the arrangement order in the second direction B is the same. When the cell slices are connected with the welding ribbon 30, the welding ribbon 30 can be used as follows Figure 2Bend as shown in . Figure 2 Two bending methods of the welding ribbon 30 are shown, which makes the serial connection between the battery cells more flexible. This application does not specifically limit the method of connecting the welding ribbon to the battery cells.

[0051] In the case of a photovoltaic module with a main grid, in some optional embodiments, such as Figure 4 As shown, the photovoltaic module further includes a plurality of first main grids 51 and a plurality of second main grids 52. The first main grids 51 and the second main grids 52 extend along a first direction A. The polarities of the first main grids 51 and the second main grids 52 are opposite. The welding strips (not shown, refer to Figure 2 The insulating through hole 12 is at least located directly below the welding strip.

[0052] In the above optional embodiment, Figure 4 The diagram shows an example in which the first doped semiconductor layer (not shown) and the second doped semiconductor layer (not shown) on both sides of the isolation region are arranged in the same order along the second direction B of the photovoltaic module. Figure 4 As shown, in the case of a back-contact solar cell with a busbar, the fine grids in the cell extend along the second direction B of the cell and directly contact the first and second doped semiconductor layers on the cell, collecting photogenerated carriers generated within the cell. The first busbar 51 is connected to the fine grid of the first doped semiconductor layer of the cell slice where it is located, and the second busbar 52 is connected to the fine grid of the second doped semiconductor layer of the cell slice where it is located. The first and second busbars 51, 52 collect the current collected by the fine grids, forming the main current transmission line. Welding ribbons then connect the first and second busbars 51, 52 in adjacent cell slices, connecting the adjacent cell slices in series and thus achieving current convergence within each cell slice.

[0053] The first main grid 51 and the second main grid 52 in adjacent cell slices are connected by welding strips, forming a small loop inside the cell: first doped semiconductor layer - first main grid 51 - welding strip - second main grid 52 - second doped semiconductor layer - isolation region between the second doped semiconductor layer and the first doped semiconductor layer. A small number of carriers meet and recombine in the isolation region between the second doped semiconductor layer and the first doped semiconductor layer, resulting in energy loss. The insulating through hole 12 provided in the isolation region of the present application can largely block the above-mentioned small loop, reduce unnecessary carrier recombination in the battery, and thus improve battery efficiency.

[0054] In the case of a photovoltaic module without a busbar, some optional embodiments further include a plurality of first and second fine grids, the first and second fine grids extending in a second direction and having opposite polarities. Welding ribbons are connected to the first and second fine grids on different cell slices, respectively, with insulating vias located at least directly beneath the welding ribbons. The welding ribbons are directly connected to the alternating first and second busbars to converge current. Placing insulating vias directly beneath the welding ribbons can reduce carrier recombination in the isolation region of the cell slice directly beneath the welding ribbons, minimizing unnecessary carrier recombination and improving cell efficiency.

[0055] In the case of a photovoltaic module without a main grid, in some optional embodiments, Figure 5 The example shown in FIG. 1 is an example in which the first doped semiconductor layer and the second doped semiconductor layer on both sides of the isolation region are arranged in the opposite order along the second direction B of the photovoltaic module. Figure 5 As shown, the photovoltaic module also includes multiple first connecting portions 61 and multiple second connecting portions 62. The first connecting portions 61 connect to the first fine grids, and the second connecting portions 62 connect to the second fine grids. This solution, based on the aforementioned busbar-less solution, includes first and second connecting portions 61 and 62. The first fine grids can be red lines extending along the second direction B, and the second fine grids can be green lines extending along the second direction B. Alternatively, the first fine grids can be green lines extending along the second direction B, and the second fine grids can be red lines extending along the second direction B. The fine grids extend along the second direction B of the photovoltaic module. The first fine grids contact the first doped semiconductor layer, and the second fine grids contact the second doped semiconductor layer. The first and second fine grids are used to collect photogenerated carriers generated by the cells. The first connecting portions 61 are used to combine the current collected by the first fine grids, and the second connecting portions 62 are used to combine the current collected by the second fine grids. Welding ribbons (not shown) connect the first and second connecting portions 61 and 62 on adjacent cell segments in series to combine the current collected by the first and second fine grids. The insulating through hole 12 is arranged directly below the soldering strip, which can reduce the collision and recombination of electrons and holes on both sides of the insulating through hole 12, thereby improving the battery efficiency.

[0056] in Figures 4 and 5 The insulating through hole 12 in the embodiment is filled, and in fact, the insulating through hole 12 is a through hole.

[0057] In a busbar-based design, the welding ribbon is welded to the fine grid, conducting the current from the fine grid to the external circuit, creating a reliable electrical connection and connecting adjacent cell slices in series. The welding ribbon and fine grid form a grid-like layout on the cell. In a busbar-free design, the busbar lines prevent the cell from being obstructed by the cell, thereby increasing the cell's light-receiving area and conversion efficiency. Furthermore, the combination of the welding ribbon and fine grid further optimizes the current flow path within the cell, reducing internal resistance and improving current transmission efficiency. The busbar-free design is suitable for photovoltaic modules that require higher conversion efficiency and a more aesthetically pleasing appearance.

[0058] In the schemes with and without main grids, the distance between the insulating through holes is not less than 5 mm, which will not affect the supporting force of the photovoltaic module, so as to reduce stress failure caused by opening the holes. In some optional embodiments, the number of insulating through holes is 20 to 60. For conventional welding assembly processes, the diameter of each perforation is in the range of 0.3 mm to 3 mm, and the insulating through holes can be circular holes, which can prevent dirt, chemical reagents and other substances from remaining on the rough interface inside the hole. Through simulation experiments, it is known that when the number of insulating through holes is within the above range, it can take into account that the battery cell has sufficient supporting force and the battery has high efficiency. The cross-section of the insulating through hole can also be other shapes, such as rectangular and trapezoidal, etc., which are not specifically limited in this application.

[0059] More specifically, the inner diameter of the insulating through-holes can be 0.5 mm to 1.5 mm. Within this range, the support of the photovoltaic module (as reflected by the fragmentation rate) is significantly affected by the number of insulating through-holes. Therefore, controlling the number of insulating through-holes is essentially sufficient. During the photovoltaic module production process, only one variable needs to be controlled to produce a qualified photovoltaic module, simplifying the process conditions. Furthermore, the inner diameter of the insulating through-holes within this range can effectively prevent carrier recombination, ensure the support of the cell, and reduce the fragmentation rate.

[0060] In the case where the photovoltaic module is a stacked grid, in some optional embodiments, such as Figure 6 As shown, the photovoltaic module further includes a plurality of first fine grids and a plurality of second fine grids, the first fine grids and the second fine grids extending along a first direction A, the first fine grids and the second fine grids having opposite polarities, the welding strips 30 are respectively connected to the first fine grids and the second fine grids on different cell slices, and the insulating through hole 12 is at least located directly below the welding strips 30. Figure 6 The dotted lines in the figure, the second fine grid can be Figure 6The solid lines in the figure, or the first fine grid can be a solid line and the second fine grid can be a dotted line. The material of the above-mentioned first fine grid and the second fine grid can be silver or copper. The first fine grid and the second fine grid are also the seed layers of the solar cell. The seed layer connecting the first doped semiconductor layer is the first fine grid, and the seed layer connecting the second doped semiconductor layer is the second fine grid. The welding strips are connected to the first fine grid and the second fine grid respectively, and the welding strips can be triangular conductive wires. Since the grid lines of the stacked grid are extremely fine, in order to ensure the current output efficiency of the battery, the grid lines of the stacked grid are distributed densely. The welding strips 30 connecting the grid lines are narrower in width and more in number than the welding strips 30 in the main grid and no main grid schemes. While ensuring that the battery cell has sufficient supporting force, as many insulating through-holes 12 as possible can be set under the welding strips 30 to reduce the electrons and holes on both sides of the insulating through-holes 12 from meeting and then generating recombination.

[0061] For the above-mentioned stacked grid structure cell, the distance between the apertures is not less than 0.1mm to reduce stress failure caused by the openings. The area of ​​the insulating through-holes accounts for 1×10 -4 %~5×10 -2 %between.

[0062] Due to the stacked grid scheme (such as Figure 6 ) where the gate lines and solder strips are densely distributed, in some optional embodiments, the inner diameter of the insulating via is set to 0.02mm-0.5mm. This allows an insulating via to be provided directly below each solder strip, physically blocking the recombination path of carriers in the isolation region and reducing recombination.

[0063] According to one aspect of the present application, a method for preparing a photovoltaic module is provided, such as Figure 7 As shown, the preparation method is used to prepare the above-mentioned photovoltaic module, comprising:

[0064] Step S201, forming a plurality of battery strings, wherein the plurality of battery strings are formed by sequentially connecting a plurality of battery cells in series along a first direction;

[0065] Specifically, the battery cell may be a back contact battery.

[0066] Step S202: forming an isolation region in the center area of ​​the solar cell to separate the solar cell into a first solar cell segment and a second solar cell segment, wherein the isolation region extends along a second direction, and a plurality of insulating through holes are sequentially provided in the isolation region along the second direction, wherein the first direction intersects the second direction, and the insulating through holes penetrate the photovoltaic module along the thickness direction of the photovoltaic module;

[0067] Specifically, the preparation process of the insulating through-hole can be laser perforation. After the insulating through-hole is formed, the front surface of the battery cell can be texturing, polishing, coating passivation and other processes. While saving the cost of the passivation process, it can also further reduce the damage to the battery caused by the formation of the insulating through-hole, thereby further reducing the loss of battery efficiency.

[0068] Step 203: providing a plurality of welding ribbons, and connecting the welding ribbons to the first battery slice and the second battery slice respectively.

[0069] Specifically, the two ends of the welding ribbon are connected to semiconductor layers of different doping types to achieve series connection between the first battery slice and the second battery slice, and to converge the currents of the adjacent first battery slice and the second battery slice.

[0070] The photovoltaic module prepared by the above preparation method is provided with a plurality of insulating through-holes in the isolation area where the cell is originally required to be laser-scribed. The insulating through-holes physically isolate the positive and negative electrodes of the cell located on both sides of the insulating through-holes, so that at least the electrons and holes on both sides of the insulating through-holes will not meet and recombine, thereby reducing the energy loss caused by the recombination of photogenerated carriers and improving the cell efficiency. In the prior art, after the cell is scribbled, the scribed area is further passivated to ensure the insulation performance of the cell. In the present application, after the insulating through-holes are formed in the isolation area, the insulating through-holes can be passivated and polished at the same time when the cell is completely polished and passivated, thereby reducing the cost of the passivation process on the edge of the scribbled area. This solves the problem in the prior art that it is impossible to take into account both cell efficiency and preparation cost when stringing solar cells.

[0071] In some optional embodiments, such as Figure 8As shown, the isolation region 11 of the battery string is laser-perforated to form an insulating through-hole 12. As shown in FIG9 , after the step of forming multiple isolation regions 11, the preparation method further includes: forming a passivation layer 24 on at least part of the first surface and the second surface of the substrate 20 of the battery cell and the sidewalls of the insulating through-hole 12, the first surface and the second surface being opposite surfaces of the substrate 20, and performing a texturing treatment on the passivation layer 24 located on the second surface. The passivation layer 24 also covers the sidewalls of the first doped semiconductor layer 21 and the second doped semiconductor layer 22 and the side surface of the first doped semiconductor layer 21 and the second doped semiconductor layer 22 facing away from the second surface, wherein the passivation layer 24 located on the side surface and the second surface of the first doped semiconductor layer 21 and the second doped semiconductor layer 22 facing away from the second surface can passivate the front and back of the battery cell and improve the interface quality. The passivation layer 24 located on the sidewalls of the insulating through-hole 12 further isolates and insulates the first doped semiconductor layer 21 and the second doped semiconductor layer 22, thereby suppressing indirect carrier recombination at the interface between the first doped semiconductor layer 21 and the second doped semiconductor layer 22. This avoids the problem of reduced photocurrent in the cell due to carrier recombination, ensures the carrier concentration in the cell, and thus achieves a high photoelectric conversion efficiency for the cell. Furthermore, the texturing-treated passivation layer can reduce the reflectivity of sunlight, enhance the absorption of light energy, and improve light absorption efficiency.

[0072] In the above optional implementation manner, if Figure 8 and Figure 9 As shown, a tunneling passivation layer 23, a first doped semiconductor layer 21, a second doped semiconductor layer 22, and a gate line 40 are formed on the first surface of the substrate 20, and a passivation layer 24 is formed on the second surface, the first doped semiconductor layer 21, the second doped semiconductor layer 22, and the sidewalls of the formed insulating through-hole 12. Texturing is performed on the passivation layer 24 located on the second surface. The above-mentioned texturing processes may include wet chemical texturing, dry texturing, mechanical grinding texturing, laser texturing, and electrochemical texturing, and the process for forming the passivation layer 24 may be physical vapor deposition, chemical vapor deposition, and other processes.

[0073] In some optional embodiments, after the step of texturing the passivation layer on the second surface, as shown in FIG. Figure 10 As shown, the preparation method also includes: providing a plurality of welding strips 30, and electrically connecting the plurality of welding strips 30 to the first doped semiconductor layer 21 of the first battery slice and the second doped semiconductor layer 22 of the second battery slice, respectively, the first battery slice and the second battery slice are adjacent battery slices, and the first doped semiconductor layer 21 and the second doped semiconductor layer 22 are both located on the first surface of the substrate 20.

[0074] In the above optional implementation, Figure 10 For example, Figure 10The figure shows a busbar-less cell structure. A soldering ribbon 30 is connected in series to the first fine grid (the left grid line 40, connected to the first doped semiconductor layer 21) on the first cell segment and the second fine grid (the right grid line 40, connected to the second doped semiconductor layer 22) on the second cell segment. Multiple cell segments are connected in series to form a cell string for current aggregation. For a stacked grid solution, the direction of the grid line 40 should align with the direction of the soldering ribbon 30.

[0075] in Figure 9 and Figure 10 The unfilled insulating through-holes 12 also have a passivation layer 24 , but for the sake of illustration, the passivation layer 24 is not drawn.

[0076] In existing technologies, laser scribing and laser drilling processes are performed within the finished cell, without subsequent passivation, which significantly reduces cell efficiency. However, the insulating vias in this application are fabricated before cell texturing, followed by a complete polishing, coating, and passivation process. Therefore, the insulating vias in this application have virtually no impact on cell efficiency, significantly reducing cutting damage compared to conventional half-cell scribing to create components.

[0077] In order to enable those skilled in the art to more clearly understand the technical solution of the present application, the implementation process of the method for preparing the photovoltaic module of the present application will be described in detail below with reference to specific embodiments.

[0078] This embodiment relates to a specific method for preparing a photovoltaic module, taking a battery without a busbar as an example, and includes the following steps:

[0079] Step S1: forming a plurality of battery strings, wherein the plurality of battery strings are formed by sequentially connecting a plurality of battery cells in series along a first direction;

[0080] Step S2: forming an isolation region in the central area of ​​the solar cell to separate the solar cell into a first solar cell segment and a second solar cell segment, wherein the isolation region extends along a second direction, and a plurality of insulating through holes are sequentially provided in the isolation region along the second direction, wherein the first direction intersects the second direction, and the insulating through holes penetrate the photovoltaic module along a thickness direction of the photovoltaic module;

[0081] Step S3: forming a passivation layer on the first surface, the second surface and the sidewalls of the insulating through-hole of the substrate of the battery cell, wherein the first surface and the second surface are opposite surfaces of the substrate, and performing a texturing treatment on the passivation layer on the second surface;

[0082] Step S4: providing a plurality of welding ribbons, which are respectively connected to the first battery slice and the second battery slice, wherein the plurality of welding ribbons are respectively connected to the first doped semiconductor layer of the first battery slice and the second doped semiconductor layer of the second battery slice, the first battery slice and the second battery slice are adjacent battery slices, and the first doped semiconductor layer and the second doped semiconductor layer are both located on the first surface.

[0083] In order to enable those skilled in the art to more clearly understand the technical solution of the present application, the photovoltaic module of the present application will be described in detail below with reference to specific embodiments.

[0084] Example 1

[0085] A photovoltaic module proposed in this embodiment includes:

[0086] A battery string formed by connecting a plurality of battery cells in series in a first direction;

[0087] An isolation area is set in the central area of ​​the battery cell to separate the battery cell into a first battery slice and a second battery slice. The isolation area extends along the second direction. A plurality of insulating through holes are sequentially arranged in the isolation area along the second direction. The first direction intersects with the second direction. The insulating through holes penetrate the photovoltaic module along the thickness direction of the photovoltaic module. A plurality of welding strips are respectively connected to the first battery slice and the second battery slice. The number of insulating through holes is 20.

[0088] Example 2

[0089] The photovoltaic module proposed in this embodiment is different from that in Embodiment 1 in that the number of insulating through holes is 30.

[0090] Example 3

[0091] A photovoltaic module proposed in this embodiment includes:

[0092] The difference from Example 1 is that the number of insulating through holes is 60.

[0093] Example 4

[0094] A photovoltaic module comprising:

[0095] The difference from Example 1 is that the number of insulating through holes is ten.

[0096] Example 5

[0097] A photovoltaic module comprising:

[0098] The difference from Example 1 is that the number of insulating through holes is 80.

[0099] Example 6

[0100] A photovoltaic module comprising:

[0101] The difference from Example 1 is that the number of insulating through holes is 100.

[0102] The photovoltaic modules in the above-mentioned Examples 1 to 6 were subjected to performance tests, wherein the aperture of the insulating through-holes in the photovoltaic modules was 0.5 mm to 1.5 mm. The test results are shown in the following table.

[0103]

[0104] When the aperture of the insulating through-hole is 0.5mm~1.5mm, the fragmentation rate and battery efficiency of the photovoltaic module are mainly affected by the insulating through-hole. It can be seen from the data in the above table that the efficiency of the photovoltaic modules in Examples 1~3 of the present application is higher than that of the photovoltaic module in Example 4. Although the fragmentation rate in Example 4 is lower, the efficiency of the photovoltaic module is too low, lower than the factory standard of the photovoltaic module, and does not meet the current requirements. The efficiency of the photovoltaic modules in Examples 1~3 of the present application is slightly lower than that in Examples 5~6, and it can be seen from the data that after the number of insulating through-holes reaches 60, the efficiency of the photovoltaic module has basically been increased to the maximum and will not be further increased, and the fragmentation rate in Examples 1~3 is significantly lower than the fragmentation rate in Examples 5~6.

[0105] In summary, the present application sets the number of insulating through holes in the above-mentioned photovoltaic module within the range of 20 to 60, which not only has higher efficiency, but also ensures that the battery has sufficient supporting force, reduces the battery fragmentation rate, and has an unexpected effect.

[0106] The above are merely preferred embodiments of the present application and are not intended to limit the present application. Those skilled in the art will readily appreciate that various modifications and variations are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. A photovoltaic module, characterized in that: include: A plurality of battery strings, wherein the plurality of battery strings are formed by connecting a plurality of battery cells in series in a first direction; An isolation region is provided in a central area of ​​the cell to separate the cell into a first cell segment and a second cell segment, the isolation region extends along a second direction, a plurality of insulating through holes are sequentially provided in the isolation region along the second direction, the first direction intersects the second direction, and the insulating through holes penetrate the photovoltaic module along a thickness direction of the photovoltaic module; a plurality of welding ribbons, each of which is connected to the first battery slice and the second battery slice, wherein the insulating through hole is at least located directly below the welding ribbons; A substrate having a first surface, the first surface including a first doped semiconductor layer and a second doped semiconductor layer, the first doped semiconductor layer and the second doped semiconductor layer having opposite doping types, and the insulating through hole being used to isolate electrons and holes between the first doped semiconductor layer of the first battery segment and the second doped semiconductor layer of the second battery segment.

2. The photovoltaic module according to claim 1, characterized in that The photovoltaic module also includes multiple first main grids and multiple second main grids, the first main grids and the second main grids extend along the first direction, the polarities of the first main grids and the second main grids are opposite, and the welding strips are respectively connected to the first main grids and the second main grids located on different battery slices.

3. The photovoltaic module according to claim 1, characterized in that The photovoltaic module also includes a plurality of first fine grids and a plurality of second fine grids, wherein the first fine grids and the second fine grids extend along the second direction, and the polarities of the first fine grids and the second fine grids are opposite, and the welding strips are respectively connected to the first fine grids and the second fine grids located on different battery slices.

4. The photovoltaic module according to claim 3, characterized in that The photovoltaic assembly further includes a plurality of first connection portions and a plurality of second connection portions, wherein the first connection portions are connected to the first fine grids, and the second connection portions are connected to the second fine grids.

5. The photovoltaic module according to claim 1, characterized in that The photovoltaic module also includes a plurality of first fine grids and a plurality of second fine grids, wherein the first fine grids and the second fine grids extend along the first direction, and the polarities of the first fine grids and the second fine grids are opposite, and the welding strips are respectively connected to the first fine grids and the second fine grids located on different battery slices.

6. The photovoltaic module according to claim 1, characterized in that The first doped semiconductor layers and the second doped semiconductor layers are alternately arranged along the second direction.

7. The photovoltaic module according to claim 6, characterized in that: The first doped semiconductor layer in the first battery slice and the first doped semiconductor layer in the second battery slice are located on both sides of the isolation region in the first direction in a one-to-one correspondence, and the second doped semiconductor layer in the first battery slice and the second doped semiconductor layer in the second battery slice are located on both sides of the isolation region in the first direction in a one-to-one correspondence.

8. The photovoltaic module according to claim 6, characterized in that: The first doped semiconductor layer in the first battery slice and the second doped semiconductor layer in the second battery slice are located on both sides of the isolation region in the first direction in a one-to-one correspondence, and the second doped semiconductor layer in the first battery slice and the first doped semiconductor layer in the second battery slice are located on both sides of the isolation region in the first direction in a one-to-one correspondence.

9. The photovoltaic module according to claim 1, characterized in that: The number of the insulating through holes is 20 to 60.

10. The photovoltaic module according to any one of claims 2 to 4, characterized in that: The inner diameter of the insulating through hole is 0.3 mm to 3 mm.

11. The photovoltaic module according to claim 10, characterized in that: The inner diameter of the insulating through hole is 0.5 mm to 1.5 mm.

12. The photovoltaic module according to claim 5, characterized in that: The inner diameter of the insulating through hole is 0.02 mm to 0.5 mm.

13. A method for preparing a photovoltaic module, characterized in that: The preparation method is used to prepare the photovoltaic module according to any one of claims 1 to 12, comprising: forming a plurality of battery strings, wherein the plurality of battery strings are formed by sequentially connecting a plurality of battery cells in series along a first direction; An isolation region is formed in a central area of ​​the cell to separate the cell into a first cell segment and a second cell segment, the isolation region extends along a second direction, a plurality of insulating through holes are sequentially provided in the isolation region along the second direction, the first direction intersects the second direction, and the insulating through holes penetrate the photovoltaic module along a thickness direction of the photovoltaic module; A plurality of welding ribbons are provided, and the welding ribbons are respectively connected to the first battery slice and the second battery slice.

14. The preparation method according to claim 13, characterized in that After the step of forming the isolation region, the preparation method further comprises: forming a passivation layer on at least a portion of a first surface and a second surface of a substrate of the battery cell and a sidewall of the insulating through hole, wherein the first surface and the second surface are opposite surfaces of the substrate; The passivation layer on the second surface is subjected to a texturing process.

15. The preparation method according to claim 14, characterized in that After the step of performing texturing on the passivation layer on the second surface, the preparation method further comprises: A plurality of welding strips are provided, and the plurality of welding strips are respectively connected to the first doped semiconductor layer of the first battery segment and the second doped semiconductor layer of the second battery segment, the first battery segment and the second battery segment are adjacent battery segments, and the first doped semiconductor layer and the second doped semiconductor layer are both located on the first surface.

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