Photovoltaic module and preparation method thereof

Abstract

The invention provides a photovoltaic module and a preparation method thereof, the photovoltaic module comprises a plurality of battery strings, and the plurality of battery strings are formed by sequentially connecting a plurality of battery pieces in series along a first direction; an isolation area is arranged in the center area of the battery piece to divide the battery piece into a first battery sub-piece and a second battery sub-piece, the isolation area extends in the second direction, a plurality of insulation through holes are sequentially formed in the isolation area in the second direction, and the first direction intersects with the second direction; the insulating through hole penetrates through the photovoltaic module along the thickness direction of the photovoltaic module; and the plurality of welding strips are respectively connected with the first battery sub-sheet and the second battery sub-sheet. The positive electrodes and the negative electrodes of the battery pieces located on the two sides of the insulation through holes are physically isolated through the insulation through holes, it is guaranteed that the adjacent battery pieces isolated by the insulation through holes cannot be short-circuited when connected in series, and damage to the battery caused by laser scribing is avoided; the problem that in the prior art, when series welding is conducted on photovoltaic modules, the battery efficiency and the preparation cost cannot be considered at the same time is solved.

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] Before the traditional back-contact solar cells are connected in series at the module end, the cells need to be cut into two halves by laser. Although this cutting method can realize the series connection of the cells, 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, this technology is complex 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 welding ribbons, a short circuit will occur due to the lack of effective isolation between the positive and negative poles of the battery. Summary of the invention

[0003] The main purpose of the present application is to provide a photovoltaic module and a method for preparing the same, so as to solve the problem in the prior art that both cell efficiency and preparation cost cannot be taken into account when performing series welding of photovoltaic modules.

[0004] In order to achieve the above-mentioned purpose, according to one aspect of the present application, a photovoltaic module is provided, including: a plurality of battery strings, wherein the plurality of battery strings are formed by a plurality of battery cells connected in series in sequence along a first direction; an isolation region is arranged 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 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 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, 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 component also 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 connection parts and a plurality of second connection parts, wherein the first connection parts are connected to the first fine grids, and the second connection parts 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 also 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 cells connected in series in sequence along a first direction; forming an isolation region in the central area of ​​the battery cell to separate the battery cell into a first battery slice and a second battery slice, wherein the isolation region extends along a second direction, and the isolation region 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 in 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, the second surface and the side wall of the insulating through hole of the substrate of the battery cell, 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 a 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 the present application, the photovoltaic module includes a plurality of battery strings formed by a plurality of battery cells connected in series in a first direction, an isolation region 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 region extends along a second direction, a plurality of insulating through holes are sequentially set 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; and also includes a plurality of welding strips, which are respectively connected to the first battery slice and the second battery slice. By setting a plurality of insulating through holes in the isolation region 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 then 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 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 of the passivation process on the edge of the dicing area, thereby solving the problem in the prior art that it is impossible to take into account both the battery efficiency and the preparation cost when stringing solar cells. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

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

[0026] Figure 6 A schematic diagram of a top view of a fifth photovoltaic assembly provided according to an embodiment of the present application is shown;

[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 A schematic diagram of the cross-sectional structure of a substrate after an insulating through hole is formed in a method for preparing a photovoltaic module provided in an embodiment of the present application is shown;

[0029] Fig. 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] Fig.10 Shown in Fig. 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 area; 12. Insulating through hole; 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 part; 62. Second connecting part. DETAILED DESCRIPTION

[0033] It should be noted that the following detailed descriptions are illustrative and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those 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, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0035] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so as to describe the embodiments of the present invention described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[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 there may be intermediate elements. Moreover, 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 component end. Although this cutting method can realize the serial connection of the cells, it also brings about laser cutting damage, resulting in reduced component 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 welding ribbons, a short circuit will occur due to the lack of effective isolation between the positive and negative electrodes of the battery. In order to solve the problem that the battery efficiency and preparation cost cannot be taken into account when the solar cells are serially welded, the embodiments of the present application provide a photovoltaic component and a preparation method thereof.

[0038] According to one aspect of the present application, Figure 1 and Figure 2 As shown, a photovoltaic module is provided, including: a plurality of battery strings, 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 arranged 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, a plurality of insulating through holes 12 are arranged in the isolation region 11 in sequence 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 strips 30, the welding strips 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 then 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 passivate and polish the insulating through holes at the same time when the battery cell is completely polished and passivated, thereby reducing the cost of the passivation process on the edge of the scribe area. This solves the problem in the prior art that it is impossible to take into account both the battery efficiency and the preparation cost when the solar cells are serially soldered.

[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 is not a center point area in the conventional sense. The first battery cell, the second battery cell and the isolation area 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 subjected to processes such as texturing, polishing, and coating passivation. 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 two ends of the above-mentioned welding ribbon are connected to semiconductor layers of different doping types to realize the series connection between the first cell slice and the second cell slice, and to converge the currents of the adjacent first cell slice and the second cell slice. After the welding ribbon connects the first doped semiconductor layer of the first cell slice and the second doped semiconductor layer of the second cell slice (or connects the second doped semiconductor layer of the first cell slice and the first doped semiconductor layer of the second cell slice), when the solar cell is exposed to light, the 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 electric field inside the battery, and the electrons move to the N-type first doped semiconductor layer (or the N-type second doped semiconductor layer), while the holes move to the P-type second doped semiconductor layer (or the P-type first doped semiconductor layer). However, in the isolation area of ​​the battery, that is, the area between the positive and negative electrodes that is 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, the electrons and holes on at least both sides of the insulating through hole can be prevented from meeting and then recombining, thereby reducing the energy loss caused by the recombination of photogenerated carriers and improving the battery efficiency.

[0043] In practical applications, the conductive channel in the cell is not only a diffusion layer, but a composite conductive (diffusion layer + body region). Especially in the normal working state of the solar cell, the excess photogenerated carriers generated in the body region also have excellent carrier transmission capacity. In the prior art, a laser scribing process is usually used to form an insulating groove or insulating line in the diffusion doping layer to separate the diffusion layer of the positive and negative electrodes to prevent direct electrical contact. However, the above-mentioned method of forming an insulating dividing line separating the diffusion layer cannot achieve complete insulation. Laser scribing may leave tiny conductive paths at the edge of the groove, which may cause leakage or short circuit under high voltage. Only physical isolation can achieve true insulation. The present application proposes to form physical through holes in the area to be isolated by laser perforation technology before the cell is made, rather than relying solely on the insulating grooves formed by laser scribing. The physical through hole can completely isolate the internal conductive path 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 extending 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 prior art, and the embodiment of the present application is not specifically limited. Figure 1 and Figure 2 Only the positional relationship among the first doped semiconductor layer 21 , the second doped semiconductor layer 22 , the soldering strip 30 and the insulating through hole 12 is illustrated.

[0045] In some optional embodiments, such as Figure 3As shown, the substrate 20 has a first surface, the first surface includes 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 alternately arranged along the second direction B, and the doping types of the first doped semiconductor layer 21 and the second doped semiconductor layer 22 are opposite. The first doped semiconductor layer 21 can be a structure in the first battery slice, the second doped semiconductor layer 22 can be a structure in the second battery slice, the insulating through hole 12 is located in the isolation area, and the gate line 40 is a fine grid of the battery slice. 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, and a passivation layer 24 is covered on the first doped semiconductor layer 21, the second doped semiconductor layer 22, the second surface and the sidewall of the insulating through hole 12, and the passivation layer 24 located on the second surface is subjected to a velvet treatment to form a velvet surface 241. The passivation layer 24 located on the first surface and the second surface can passivate the front and back of the battery slice to improve the interface quality. The passivation layer 24 located at the side wall of the insulating through hole 12 further isolates and insulates the first doped semiconductor layer 21 and the second doped semiconductor layer 22, which can inhibit the indirect carrier recombination at the interface between the first doped semiconductor layer 21 and the second doped semiconductor layer 22, thereby avoiding the problem of reduced photocurrent of the cell due to carrier recombination, ensuring the concentration of carriers in the cell, and thus making the photoelectric conversion efficiency of the cell higher. The material of the above-mentioned passivation layer 24 can be a single layer or a composite layer such as aluminum oxide, silicon nitride, silicon oxide and silicon oxynitride.

[0046] In some embodiments, the material of the substrate may be an elemental semiconductor material. The elemental semiconductor material is composed of a single element, such as silicon or germanium. The elemental semiconductor material may be at least one of a single crystal state, a polycrystalline state, an amorphous state, or a microcrystalline state (a state having both a single crystal state and an amorphous state 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 one of the V-group elements such as phosphorus (P), bismuth (Bi), antimony (Sb), or arsenic (As). The P-type semiconductor substrate is doped with a P-type element, which may be any one of the III-group 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 battery 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 side of the isolation region 11 along the second direction B is: the second doped semiconductor layer 22, the first doped semiconductor layer 21, the second doped semiconductor layer 22 and the first doped semiconductor layer 21. The arrangement order of the first doped semiconductor layer 21 and the second doped semiconductor layer 22 on the right side of the isolation region 11 along the second direction B is: the first doped semiconductor layer 21, the second doped semiconductor layer 22, the first doped semiconductor layer 21 and the 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 opposite. When the battery slices are connected with the welding ribbon 30, the welding ribbon 30 can be extended along the first direction A, and can be directly connected in series with the different polarities of the adjacent battery slices for current aggregation. There is no need to bend the welding ribbon 30, which simplifies the preparation process of the welding 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 battery 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: the first doped semiconductor layer 21, the second doped semiconductor layer 22, the first doped semiconductor layer 21 and the second doped semiconductor layer 22. The positions of the doped regions on the left and right sides correspond to each other, and the arrangement order in the second direction B is the same. When the battery 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 illustrated, so that the serial connection method between the battery cells is more flexible. This application does not specifically limit the method of connecting the welding ribbon to the battery cells.

[0051] In the case where the photovoltaic module has a main grid, in some optional embodiments, such as Figure 4 As shown, the photovoltaic module also 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 first main grids 51 and the second main grids 52 have opposite polarities, and the welding strips (not shown, can refer to Figure 2 The insulating through hole 12 is at least located directly below the welding strip.

[0052] In the above optional implementation, Figure 4 Schematically shown is an example in which the first doped semiconductor layer (not shown) and the second doped semiconductor layer (not shown) located 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 main grid, the fine grid in the cell extends along the second direction B of the cell and directly contacts the first doped semiconductor layer and the second doped semiconductor layer on the cell sheet to collect the photogenerated carriers generated inside the cell. The first main grid 51 is connected to the fine grid of the first doped semiconductor layer of the cell slice where it is located, and the second main grid 52 is connected to the fine grid of the second doped semiconductor layer of the cell slice where it is located. The first main grid 51 and the second main grid 52 collect the current collected by the fine grid to form a main transmission line for the current. The welding strip then connects the first main grid 51 and the second main grid 52 in the adjacent cell slices respectively, so as to connect the adjacent cell slices in series, thereby realizing the current convergence of each cell slice.

[0053] The first main grid 51 and the second main grid 52 in adjacent battery slices are connected by welding strips, forming a small loop inside the battery slice: the first doped semiconductor layer--the first main grid 51--welding strip--the second main grid 52--the second doped semiconductor layer--the 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 of the battery, and thus improve battery efficiency.

[0054] In the case where the photovoltaic module is without a main grid, in some optional embodiments, 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. The welding strips are directly connected to the first and second main grids that are alternately distributed to converge the current. The insulating through holes are arranged directly below the welding strips, which can reduce the carrier recombination of the isolation area of ​​the battery slice directly below the welding strips, reduce unnecessary carrier recombination, and improve battery 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 located 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 a plurality of first connection parts 61 and a plurality of second connection parts 62, the first connection part 61 is connected to the first fine grid, and the second connection part 62 is connected to the second fine grid. This scheme is provided with a first connection part 61 and a second connection part 62 on the basis of the above-mentioned busbar-free scheme. The first fine grid can be a red line extending along the second direction B, and the second fine grid can be a green line extending along the second direction B, or the first fine grid can be a green line extending along the second direction B, and the second fine grid can be a red line extending along the second direction B. The fine grid extends along the second direction B of the photovoltaic module, the first fine grid contacts the first doped semiconductor layer, and the second fine grid contacts the second doped semiconductor layer, and the first fine grid and the second fine grid are used to collect photogenerated carriers generated by the battery. The first connection part 61 is used to converge the current collected by the first fine grid, and the second connection part 62 is used to converge the current collected by the second fine grid. The welding strip (not shown) is respectively connected to the first connection part 61 and the second connection part 62 on the adjacent battery slices to be connected in series, so as to converge the current collected by the first fine grid and the second fine grid. The insulating through hole 12 is arranged directly below the welding 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 to 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 the busbar solution, the welding ribbon is in close contact with the fine grid by welding, and the current on the fine grid is led to the external circuit to form a reliable electrical connection, and the adjacent battery slices are connected in series. The welding ribbon and the fine grid form a grid layout on the battery. In the busbar-free design, the busbar line is prevented from blocking the battery area, thereby increasing the light-receiving area and conversion efficiency of the battery. At the same time, due to the combination of the welding ribbon and the fine grid, the current flow path inside the battery is further optimized, reducing the internal resistance and improving the current transmission efficiency. The busbar-free design is suitable for photovoltaic modules that pursue higher conversion efficiency and more beautiful appearance.

[0058] In the schemes with and without main grid, the distance between the insulating through holes is not less than 5mm, which will not affect the supporting force of the photovoltaic module to reduce stress failure caused by opening. 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 0.3mm to 3mm, and the insulating through holes can be circular holes, which can prevent the residual dirt, chemical reagents and other substances 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 a high efficiency. The cross-section of the insulating through hole can also be other shapes, such as rectangle and trapezoid, etc., which are not specifically limited in this application.

[0059] More specifically, the inner diameter of the insulating through hole can be 0.5 mm to 1.5 mm. Within this range, the support of the photovoltaic module (expressed as the fragmentation rate) is greatly affected by the number of insulating through holes. At this time, it is basically only necessary to control the number of insulating through holes. In the process of preparing photovoltaic modules, only one variable is controlled to prepare qualified photovoltaic modules, which simplifies the process conditions. The inner diameter of the insulating through hole in the above range can effectively avoid carrier recombination, ensure the support of the battery 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 extend along a first direction A, the first fine grids and the second fine grids have opposite polarities, the welding strips 30 are respectively connected to the first fine grids and the second fine grids located on different cell slices, and the insulating through hole 12 is at least located directly below the welding strips 30. The first fine grids can be 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 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 in a large density. 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. Under the condition of 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, which can reduce the electrons and holes on both sides of the insulating through holes 12 from meeting and then generating recombination.

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

[0062] Due to the stacked grid solution (such as Figure 6 ) where the gate lines and welding strips are densely distributed, in some optional implementations, the inner diameter of the insulating through hole is set to 0.02 mm to 0.5 mm. In this way, an insulating through hole can be set directly below each welding strip to physically isolate the recombination path of carriers in the isolation area and reduce 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 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 central area of ​​the battery cell to separate the battery cell into a first battery slice and a second battery slice, the isolation region extending along the second direction, a plurality of insulating through holes are sequentially arranged 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;

[0067] Specifically, the preparation process of the 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.

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

[0069] Specifically, the two ends of the welding strip are connected to semiconductor layers of different doping types to realize the 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 has multiple insulating through holes set in the isolation area where the battery cell is originally required 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 then 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 passivate and polish the insulating through holes at the same time when the battery cell is completely polished and passivated, reducing the cost of the passivation process on the edge of the scribe 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.

[0071] In some optional embodiments, such as Figure 8As shown, the isolation area 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 areas 11, the preparation method also includes: forming a passivation layer 24 on at least part of the first surface, the second surface and the side wall of the insulating through hole 12 of the substrate 20 of the battery cell, the first surface and the second surface are opposite surfaces of the substrate 20, and the passivation layer 24 located on the second surface is subjected to a texturing treatment. The passivation layer 24 also covers the side walls of the first doped semiconductor layer 21 and the second doped semiconductor layer 22 and the side surfaces of the first doped semiconductor layer 21 and the second doped semiconductor layer 22 that are 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 that are away from the second surface can passivate the front and back of the battery cell to improve the interface quality. The passivation layer 24 located at the side wall of the insulating through hole 12 further isolates and insulates the first doped semiconductor layer 21 and the second doped semiconductor layer 22, which can suppress the indirect carrier recombination at the interface between the first doped semiconductor layer 21 and the second doped semiconductor layer 22, thereby avoiding the problem of reduced photocurrent of the cell due to carrier recombination, ensuring the concentration of carriers in the cell, and thus making the photoelectric conversion efficiency of the cell higher. The passivation layer after the texturing treatment can reduce the reflectivity of sunlight, enhance the absorption of light energy, and improve the light absorption efficiency.

[0072] In the above optional implementation, if Figure 8 and Fig. 9 As shown, a tunnel 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 sidewall of the formed insulating through hole 12. Texturing is performed on the passivation layer 24 located on the second surface. The above-mentioned texturing process 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, Fig.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, Fig.10 For example, Fig.10The structure of the battery without main grid is shown in FIG. The welding strip 30 is connected in series with the first fine grid (the grid line 40 on the left, connected to the first doped semiconductor layer 21) on the first battery slice and the second fine grid (the grid line 40 on the right, connected to the second doped semiconductor layer 22) on the second battery slice, and multiple battery slices are connected in series into a battery string to achieve current aggregation. If the stacked grid solution is used, the setting direction of the grid line 40 should be consistent with the extension direction of the welding strip 30.

[0075] in Fig. 9 and Fig.10 There is also a passivation layer 24 at the unfilled insulating through hole 12, but for the sake of illustration, the passivation layer 24 is not drawn here.

[0076] In the prior art, the laser scribing and laser hole opening processes are both in the finished cell, and there is no other passivation process after this process, which will still greatly reduce the efficiency of the cell. However, the insulating through-holes in this application are made before the cell is textured, and there are complete polishing, coating and passivation processes afterwards. Therefore, the insulating through-holes made in this application have almost no damage to the cell efficiency, and compared with the conventional method of making components by scribing half a cell, it can greatly reduce cutting damage.

[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 in conjunction with specific embodiments.

[0078] This embodiment relates to a specific method for preparing a photovoltaic module, taking a battery without a main grid 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 battery cell to separate the battery cell into a first battery slice and a second battery slice, the isolation region extending along the second direction, a plurality of insulating through holes are sequentially arranged 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;

[0081] Step S3: forming a passivation layer on the first surface, the second surface and the sidewall of the insulating through hole of the substrate of the battery cell, the first surface and the second surface being 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 strips, wherein the welding strips are respectively connected to the first battery slice and the second battery slice, wherein the plurality of welding strips 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 in conjunction with 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 zone 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 zone extends along the second direction. A plurality of insulating through holes are sequentially arranged in the isolation zone 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 comprises:

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

[0096] Example 5

[0097] A photovoltaic module comprises:

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

[0099] Example 6

[0100] A photovoltaic module comprises:

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

[0102] The photovoltaic modules in the above-mentioned embodiments 1 to 6 were subjected to performance tests, wherein the aperture of the insulating through hole in the photovoltaic module 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 modules in Example 4. Although the fragmentation rate in Example 4 is lower, the efficiency of the photovoltaic modules is too low, which is lower than the factory standard of the photovoltaic modules 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 modules 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 general, 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 fragmentation rate of the battery, and has an unexpected effect.

[0106] The above are only preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope 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 the central area of ​​the battery sheet to separate the battery sheet into a first battery segment and a second battery 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 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 are respectively connected to the first battery slice and the second battery slice.

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 first main grids and the second main grids have opposite polarities, 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.

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 first fine grids and the second fine grids have opposite polarities, and 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.

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 first fine grids and the second fine grids have opposite polarities, and 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.

6. The photovoltaic module according to claim 1, characterized in that: The photovoltaic module further comprises: The substrate has a first surface, wherein the first surface includes a first doped semiconductor layer and a second doped semiconductor layer, wherein the first doped semiconductor layer and the second doped semiconductor layer are alternately arranged along the second direction, and the doping types of the first doped semiconductor layer and the second doped semiconductor layer are opposite.

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 the central area of ​​the battery sheet to separate the battery sheet into a first battery segment and a second battery segment, the isolation region extends along a second direction, a plurality of insulating through holes are sequentially arranged 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 are provided, and the welding strips 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 a texturing treatment 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 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.

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