A back contact cell, back contact laminate cell and photovoltaic module

Abstract

The application relates to the technical field of back contact cells, in particular to a back contact cell, a back contact laminated cell and a photovoltaic module. The back contact cell comprises a body, a first fine grid, a second fine grid, a harpoon structure and a spacer arranged on the body. The first fine grid and the second fine grid both extend along a first direction. The harpoon structure is in contact with the first fine grid in a third direction, that is, the harpoon structure is used for transmitting the current collected by the fine grid to the main grid. The harpoon structure can reduce the length of the main grid in the second direction, thereby reducing the material cost of the main grid. Meanwhile, the photo-generated current of the fine grid between the edge of the main grid and the body can be transmitted to the main grid by the harpoon structure, thereby improving the current collection efficiency of the edge position of the back contact cell. In the third direction, at least part of the structure of the spacer is located between the second fine grid and the harpoon structure, thereby reducing the risk of short circuit caused by the electrical connection of the first fine grid with the second fine grid through the harpoon structure.

Description

Technical Field

[0001] This application relates to the field of back contact battery technology, and more particularly to a back contact battery, a back contact tandem battery, and a photovoltaic module. Background Technology

[0002] In back-contact solar cells, both the positive and negative grids are located on the back side of the cell. The electrical connection between the positive and negative grids can lead to short circuits in the back-contact solar cells, increased energy loss in the photovoltaic module, reduced output power, and localized overheating.

[0003] Therefore, how to improve current collection efficiency while reducing the short-circuit risk of the positive and negative fine gates is an important problem that needs to be solved in this field. Summary of the Invention

[0004] This application provides a back-contact cell, a back-contact tandem cell, and a photovoltaic module, which can improve current collection efficiency while reducing the short-circuit risk of the positive and negative electrode grids.

[0005] The first aspect of this application provides a back contact battery, including a body, a first fine grid, a second fine grid, a harpoon structure, and a separator disposed on the body. The first fine grid and the second fine grid both extend along a first direction and are arranged along a second direction. The first direction intersects the second direction. The harpoon structure contacts the first fine grid in a third direction. In the third direction, at least a portion of the separator is located between the second fine grid and the harpoon structure.

[0006] In this application, the harpoon structure is used to transfer the current collected by the fine grid to the main grid. The harpoon structure can reduce the length of the main grid in the second direction, thereby reducing the material cost of the main grid. At the same time, the photocurrent of the fine grid between the edge of the main grid and the body can be transferred to the main grid by the harpoon structure, thereby improving the current collection efficiency at the edge position of the back contact battery.

[0007] The harpoon structure and the second fine grid are isolated by an isolator, which can reduce the risk of short circuit caused by the first fine grid being electrically connected to the second fine grid through the harpoon structure.

[0008] In some possible designs, the isolation member includes a first isolation member, which includes a first isolation portion and a second isolation portion extending along a first direction. The first isolation portion and the second isolation portion respectively contact the harpoon structure, and the first isolation portion and the second isolation portion are arranged at intervals along the first direction.

[0009] In some possible designs, the harpoon structure includes first and second harpoon lines spaced apart along a first direction, both extending in directions intersecting the first direction, and the first and second harpoon lines forming a fork region. A first and second isolating portion have a gap in the first direction, located within the fork region.

[0010] In some possible designs, the first isolation member also includes a third isolation section, which is located between the first isolation section and the second isolation section in the first direction.

[0011] In some possible designs, the number of third isolation sections is one, or at least two third isolation sections are arranged at intervals along the first direction.

[0012] In some possible designs, the first isolation member includes at least a first segment and a second segment arranged along the second direction, each of the first segment and the second segment including a first isolation portion, a second isolation portion and a third isolation portion, and the body including an edge extending along the first direction, and in the second direction, the second segment is located between the first segment and the edge; The number of third isolation sections in the first segment arranged in the first direction is N1, and the number of third isolation sections in the second segment arranged in the first direction is N2, where N2 > N1.

[0013] In some possible designs, the isolation element also includes a second isolation element, which is arranged along a second direction with the first isolation element, and the second isolation element extends along a first direction and penetrates the fork area.

[0014] In some possible designs, the first and second spacers are arranged alternately along the second direction.

[0015] In some possible designs, in the second direction, the first separator is adjacent to the edge of the back contact battery.

[0016] A second aspect of this application provides a back-contact stacked solar cell, including a back-contact bottom cell and a perovskite top cell, wherein the back-contact bottom cell is configured as a back-contact cell as described in any of the above claims, and the perovskite top cell is electrically connected to the light-facing surface of the back-contact bottom cell.

[0017] A third aspect of this application provides a photovoltaic module, the photovoltaic module including a cover plate, an encapsulation layer and a cell layer, the cell layer including at least one of a back contact cell and a back contact stacked cell, the back contact cell being configured as the back contact cell described in any of the above claims, and the back contact stacked cell being configured as the back contact stacked cell described above.

[0018] It should be understood that the above general description and the following detailed description are merely exemplary and do not limit this application. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 A schematic diagram of the backlight surface of the back contact battery provided in this application in some embodiments; Figure 2 for Figure 1 Enlarged view of part A in some embodiments; Figure 3 A schematic diagram of the backlight surface of the back contact battery provided in this application in some other embodiments; Figure 4 for Figure 3 Enlarged view of part B in some embodiments; Figure 5 for Figure 4 A partial structural diagram in some embodiments; Figure 6 for Figure 4 Partial structural schematic diagrams in other embodiments; Figure 7 for Figure 4 Partial structural schematic diagrams in some other embodiments; Figure 8 for Figure 4 Partial structural schematic diagrams in some other embodiments; Figure 9 for Figure 1 Cross-sectional view of the back contact battery in some embodiments; Figure 10 A schematic diagram of the back-contact stacked battery provided in this application in some embodiments; Figure 11 Exploded views of the photovoltaic module provided in this application in some embodiments; Figure 12 Exploded views of the photovoltaic modules provided in this application in other embodiments.

[0021] Figure label: 10-Back contact battery; 101-Substrate; 102-Passivation layer; 103-Antireflective layer; 104-Tunneling oxide layer; 105-N-type polycrystalline silicon layer; 106-Intrinsic amorphous silicon layer; 107-P-type amorphous silicon layer; 108-Transparent conductive layer; 1-Body; 11-Edge; 2-Main gate; 21-First main gate; 22-Second main gate; 3-Fine grid; 31-First fine grid; 32-Second fine grid; 4-Isolation components; 41-First isolation element; 411-First isolation section; 412-Second isolation section; 413-Gap; 414-Third isolation section; 41A-First segment; 41B-Second segment; 42 - Second isolation element; 5-Harpoon structure; 51-First harpoon line; 52-Second harpoon line; 53-Harpoon area; 20-Back contact stacked battery; 201-Back contact bottom cell; 202-Perovskite top cell; 30 - Solder strip; 40 - Front panel; 50 - Front encapsulation layer; 60 - Back encapsulation layer; 70 - Backplate; X - First direction; Y - Second direction; Z - Third direction. Detailed Implementation

[0022] To better understand the technical solution of this application, the embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0023] It should be understood that the described embodiments are merely some, not all, of the embodiments in this application. All other embodiments obtained by those skilled in the art based on the embodiments in this application without inventive effort are within the scope of protection of this application.

[0024] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. The singular forms “a,” “the,” and “the” used in the embodiments of this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0025] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0026] This application provides a back contact battery 10, such as Figure 1 and Figure 2As shown, the back contact battery 10 includes a body 1. The back surface of the body 1 is provided with a main grid 2 and fine grids 3. The back surface refers to the side of the back contact battery 10 that faces away from sunlight during use. The main grid 2 includes a first main grid 21 and a second main grid 22 alternately distributed along a first direction X, both extending along a second direction Y. The fine grids 3 include a first fine grid 31 and a second fine grid 32 alternately distributed along the second direction Y, both extending along the first direction X, for collecting and guiding the photocurrent generated in the body 1. The first fine grid 31 intersects with the first main grid 21 and forms an electrical connection. The electrical connection means that, in the field of power generation or power supply, there is an electrical connection between the first fine grid 31 and the first main grid 21, that is, the first fine grid 31 and the first main grid 21 can transmit current so that the first main grid 21 can collect and output the photocurrent collected by the first fine grid 31. The second fine grid 32 intersects with the second main grid 22 and forms an electrical connection so that the second main grid 22 can collect and output the photocurrent collected by the second fine grid 32.

[0027] It should be noted that the first direction X intersects with the second direction Y, such as... Figure 1 As shown, one of the first direction X and the second direction Y can be the length direction of the back contact battery 10, and the other can be the width direction of the back contact battery 10.

[0028] In this embodiment, the first main gate 21 and the second main gate 22 have opposite polarities; one is the positive main gate of the back contact battery 10, and the other is the negative main gate of the back contact battery 10. The first fine gate 31 has the same polarity as the first main gate 21, and the second fine gate 32 has the same polarity as the second main gate 22. There is one first fine gate 31 in the first direction X, meaning that the first fine gate 31 is not interrupted at the second main gate 22 with the opposite polarity. Similarly, there is one second fine gate 32 in the first direction X, meaning that the second fine gate 32 is not interrupted at the first main gate 21 with the opposite polarity.

[0029] like Figure 3 and Figure 4 As shown, the back contact battery 10 also includes a separator 4. In the third direction Z, the separator 4 is located between the first fine grid 31 and the second main grid 22, used to isolate the first fine grid 31 and the second main grid 22, thereby reducing the risk of a short circuit due to electrical connection between the first fine grid 31 and the second main grid 22. Furthermore, in the third direction Z, the separator 4 is located between the second fine grid 32 and the first main grid 21, used to isolate the second fine grid 32 and the first main grid 21, thereby reducing the risk of a short circuit due to electrical connection between the second fine grid 32 and the first main grid 21. The specific structure of the separator 4 is illustrated below. Figures 3 to 8 The first fine gate 31 and the second fine gate 32 are both hidden in the middle.

[0030] It should be noted that the third direction Z is perpendicular to the first direction X and the second direction Y. For example, the third direction Z is the thickness direction of the back contact battery 10.

[0031] The following discussion will focus on the specific structure of the isolation element 4, taking the isolation element 4 on the second fine grid 32 as an example.

[0032] In some embodiments, the separator 4 covers the entire structure of the second fine gate 32 in the first direction X.

[0033] In other embodiments, such as Figure 4 As shown, the spacer 4 covers part of the structure of the second fine grid 32 in the first direction X, which can reduce the size of the spacer 4 in the first direction X, thereby reducing the material cost of the spacer 4.

[0034] In the first direction X, the dimension of the spacer 4 in the first direction X is larger than the dimension of the first main gate 21 in the first direction X, for example, as Figure 4 As shown, in the first direction X, both ends of the isolator 4 extend to the outer edge of the first main grid 21 and are exposed. This can reduce the risk of short circuit between the second fine grid 32 and the first main grid 21 while reducing the coverage area of ​​the isolator 4 on the second fine grid 32, thereby improving the insulation and isolation effect of the isolator 4.

[0035] like Figure 4 As shown, the back contact battery 10 also includes a harpoon structure 5. One end of the harpoon structure 5 is connected to the main grid 2, and the other end extends toward the edge of the body 1. The extension direction of the harpoon structure 5 intersects with the first direction X. For example, the harpoon structure 5 extends along the second direction Y, or there is an angle greater than 0 between the extension direction of the harpoon structure 5 and both the first direction X and the second direction Y.

[0036] When the harpoon structure 5 is electrically connected to the first main grid 21, the harpoon structure 5 contacts a portion of the first fine grid 31 in the third direction Z and contacts the isolator 4 covering the second fine grid 32, so that the harpoon structure 5 is electrically connected to the first fine grid 31 and the first main grid 21. The photocurrent collected by the first fine grid 31 can be transmitted to the first main grid 21 through the harpoon structure 5. At the same time, the harpoon structure 5 and the second fine grid 32 are isolated by the isolator 4 to reduce the risk of short circuit caused by the first fine grid 31 being electrically connected to the second fine grid 32 through the harpoon structure 5.

[0037] When the harpoon structure 5 is electrically connected to the second main grid 22, the harpoon structure 5 and a portion of the second fine grid 32 are in contact in the third direction Z, and are in contact with the isolator 4 covering the first fine grid 31, so that the harpoon structure 5 is electrically connected to the second fine grid 32 and the second main grid 22. The photocurrent collected by the second fine grid 32 can be transmitted to the second main grid 22 through the harpoon structure 5. At the same time, the harpoon structure 5 and the first fine grid 31 are isolated by the isolator 4 to reduce the risk of short circuit caused by the second fine grid 32 being electrically connected to the first fine grid 31 through the harpoon structure 5.

[0038] In this embodiment, the harpoon structure 5 can reduce the length of the main grid 2 in the second direction Y, thereby reducing the material cost of the main grid 2. At the same time, the photocurrent generated by the fine grid 3 between the edge of the main grid 2 and the body 1 can be transmitted to the main grid 2 by the harpoon structure 5, thereby improving the current collection efficiency at the edge of the back contact battery 10.

[0039] The following discussion uses the first main gate 21, the harpoon structure 5 electrically connected to the first main gate 21, and the isolation member 4 used to isolate the harpoon structure 5 from the second fine gate 32 as examples to elaborate on the specific structure of the isolation member 4 at the harpoon structure 5. That is, in the third direction Z, at least part of the structure of the isolation member 4 is located between the second fine gate 32 and the harpoon structure 5.

[0040] The harpoon structure 5 includes a first harpoon line 51 and a second harpoon line 52 arranged at intervals along the first direction X. One end of the first harpoon line 51 is connected to the main grid 2 and the other end extends toward the edge of the body 1. The extension direction of the first harpoon line 51 intersects with the first direction X. One end of the second harpoon line 52 is connected to the main grid 2 and the other end extends toward the edge of the body 1. The extension direction of the second harpoon line 52 intersects with the first direction X. The first harpoon line 51 and the second harpoon line 52 are connected to the same main grid 2. The first harpoon line 51 and the second harpoon line 52 form the fork region 53 of the harpoon structure 5.

[0041] In some embodiments, the separator 4 extends along the first direction X and penetrates the fork region 53.

[0042] In other embodiments, such as Figure 5As shown, the isolation member 4 includes a first isolation member 41, which includes a first isolation portion 411 and a second isolation portion 412 extending along a first direction X. The first isolation portion 411 and the second isolation portion 412 are respectively in contact with the harpoon structure. For example, the first isolation portion 411 is in contact with the first harpoon line 51, that is, the first isolation portion 411 is located between the first harpoon line 51 and the second fine grid 32 in the third direction Z, and the second isolation portion 412 is in contact with the second harpoon line 52, that is, the first isolation portion 411 is located between the second harpoon line 52 and the second fine grid 32 in the third direction Z. The first isolation portion 411 and the second isolation portion 412 are arranged at intervals along the first direction X, that is, the first isolation portion 411 and the second isolation portion 412 have a gap 413 in the first direction X.

[0043] In this embodiment, the first isolation member 41 and the body 1 are made of different materials, resulting in different coefficients of thermal expansion. During the curing process of the first isolation member 41, or during subsequent high-temperature welding, lamination, etc., the first isolation member 41 and the body 1 deform to different degrees. The first isolation member 41 will exert a force on the body 1 due to the difference in deformation. By breaking the first isolation member 41 extending along the first direction X into a first isolation portion 411 and a second isolation portion 412, the coverage area of ​​the first isolation member 41 on the body 1 can be reduced. This reduces the force exerted by the first isolation member 41 on the body 1 during curing, high-temperature welding, lamination, etc., thereby reducing the risk of the body 1 being warped and deformed by being pulled by the first isolation member 41, and also reducing the risk of microcracks appearing in the body 1.

[0044] In some embodiments, the gap 413 may be located outside the fork region 53 in the first direction X, that is, the gap 413 may be located on one side of the harpoon structure 5 in the first direction X.

[0045] In other embodiments, such as Figure 5 As shown, gap 413 is located within the fork area 53.

[0046] In this embodiment, taking the first isolation portion 411 as an example, the longer the length of the first isolation portion 411 in the first direction X, the greater the deformation of the first isolation portion 411 during high-temperature expansion or low-temperature contraction, resulting in a greater force exerted by the first isolation portion 411 on the body 1. By placing the gap 413 within the fork region 53, the length difference between the first isolation portion 411 and the second isolation portion 412 in the first direction X can be reduced. This reduces the difference in the magnitude of the force exerted by the first isolation portion 411 and the second isolation portion 412 on the body 1, thereby improving the uniformity of stress on the body 1 and reducing the risk of warping and microcracks in the body 1.

[0047] The distance between the ends of the first isolation portion 411 and the second isolation portion 412 in the first direction X is the width of the gap 413. In some embodiments, such as... Figure 5 As shown, multiple spacers 4 are arranged along the second direction Y, such that multiple gaps 413 are arranged along the second direction Y, and the gaps 413 arranged along the second direction Y can have the same width.

[0048] In other embodiments, such as Figure 6 As shown, multiple gaps 413 are arranged along the second direction Y. The widths of the gaps 413 arranged along the second direction Y are different. For example, along the second direction Y and along the direction from the first main gate 21 to the harpoon structure 5, the width of the gaps 413 gradually increases. This can reduce the total length of the first isolation member 41 which is far from the first main gate 21, thereby further reducing the force exerted by the first isolation member 41 on the body 1 when it expands at high temperature or contracts at low temperature.

[0049] like Figure 7 As shown, the first isolation member 41 also includes a third isolation part 414. In the first direction X, the third isolation part 414 is located between the first isolation part 411 and the second isolation part 412, that is, the third isolation part 414 is located in the gap 413 and the third isolation part 414 is located in the fork region 53.

[0050] In this embodiment, when the solder strip extending along the second direction Y covers the first main gate 21, a portion of the solder strip will cover the fork region 53. When the width of the gap 413 in the first direction X is large, there is a risk that the solder strip will collapse along the third direction Z and come into contact with the second fine gate 32 with opposite polarity, resulting in a short circuit. The third isolation portion 414 within the gap 413 can support the solder strip in the third direction Z, thereby reducing the risk of short circuit due to electrical connection between the solder strip and the second fine gate 32.

[0051] In some embodiments, the number of third isolation portions 414 is one, which can reduce the difficulty of forming the third isolation portion 414. For example, it can simplify the structure of the screen used to print the third isolation portion 414, thereby reducing the printing cost of the third isolation portion 414.

[0052] In other embodiments, at least two third isolation portions are arranged at intervals along the first direction X, which can reduce the length of a third isolation portion 414, thereby reducing the force exerted by the third isolation portion 414 on the body 1 during thermal expansion and contraction, and reducing the risk of warping and microcracks in the body 1.

[0053] When multiple gaps 413 are arranged along the second direction Y, the gaps 413 arranged along the second direction Y may have the same number of third isolation portions 414.

[0054] Along the second direction Y, and along the direction from the first main gate 21 to the harpoon structure 5, as the width of the gap 413 gradually increases, the number of third isolation portions 414 within the gap 413 can also gradually increase; that is, the wider the gap 413, the more third isolation portions 414 are within the gap 413. For example, as... Figure 7 As shown, the first isolation member 41 includes at least a first segment 41A and a second segment 41B arranged along the second direction Y. Both the first segment 41A and the second segment 41B include the first isolation portion 411, the second isolation portion 412 and the third isolation portion 414 in the above embodiment. The body 1 also includes an edge 11 extending along the first direction X. In the second direction Y, the second segment 41B is located between the first segment 41A and the edge 11. The number of third isolation portions 414 of the first segment 41A arranged in the first direction X is N1, and the number of third isolation portions 414 of the second segment 41B arranged in the first direction X is N2, where N2 > N1.

[0055] In this embodiment, the closer to the edge 11, the wider the width of the fork region 53 in the first direction X. By setting more third isolation parts 414, the length of a single third isolation part 414 can be reduced while improving the support effect of the third isolation part 414 on the solder strip and reducing the risk of short circuit, thereby reducing the risk of warping and microcracks in the body 1.

[0056] like Figure 8 As shown, the isolation member 4 may also include a second isolation member 42, which is arranged along the second direction Y with the first isolation member 41, and the second isolation member 42 extends along the first direction X and penetrates the fork region 53.

[0057] In this embodiment, by setting a continuous second isolator 42 that runs through the fork region 53, when the solder strip covering the first main grid 21 is offset or bent along the first direction X, the unbroken continuous second isolator 42 can still support the solder strip, thereby reducing the risk of short circuit due to electrical connection between the solder strip and the second fine grid 32.

[0058] The first isolation member 41 and the second isolation member 42 are arranged alternately along the second direction Y. During the thermal expansion and contraction of the isolation member 4, the force of the isolation member 4 on the body 1 can be evenly distributed in the second direction Y, which can reduce the risk of the body 1 warping or microcracks caused by the greater force on one side and the less force on the other side.

[0059] In the second direction Y, the first isolation member 41 is adjacent to the edge 11 of the body 1, that is, the isolation member 4 closest to the edge 11 is the disconnected first isolation member 41 in the above embodiment.

[0060] In this embodiment, as Figure 8As shown, the first harpoon line 51 and the second harpoon line 52 extend obliquely in a Y-shape, making the width of the fork area 53 near the edge 11 larger, and making the length of the isolation member 4 closest to the edge 11 the longest. Setting the isolation member closest to the edge 11 as the first isolation member 41 can significantly reduce the force on the body during the thermal expansion and contraction of the isolation member 4, thereby significantly reducing the risk of warping, deformation and hidden cracks in the body 1.

[0061] Based on the back contact battery 10 in any of the above embodiments, the type of back contact battery 10 can be one of interdigitated back contact (IBC), heterojunction back contact (HBC), and tunnel oxide back contact (TBC). For an IBC battery, along its thickness direction, the IBC battery sequentially includes a silicon nitride inversion layer, an N+ front surface field, an N-type bulk silicon layer, a P+ emitter, an N+ back field, an aluminum oxide passivation layer, a silicon nitride antireflection layer, and a metallic silver electrode. IBC cells utilize ion implantation technology to obtain P- and N-regions with good uniformity and precise controllable junction depth. The absence of grid lines on the front of the cell eliminates light-blocking current loss from metal electrodes, maximizing the utilization of incident photons and improving short-circuit current by approximately 7% compared to conventional solar cells. Due to the back-contact structure, grid line shading is not a concern, allowing for a wider grid line ratio, thus reducing series resistance and achieving a high fill factor. Optimized design of surface passivation and light-trapping structures can be achieved, resulting in lower front-surface recombination rates and surface reflections.

[0062] HBC cells effectively combine the advantages of IBC and heterojunction cells. Their front surface passivation layer uses hydrogenated amorphous silicon, while N-type and P-type amorphous silicon films are deposited on the back side to form a heterojunction. HBC cells fully utilize the superior surface passivation properties of amorphous silicon, and the heterojunction structure formed on the back side exhibits excellent passivation, enabling the simultaneous achievement of higher short-circuit current and open-circuit voltage, thereby improving photoelectric conversion efficiency.

[0063] For TBC cells, the advantages of TOPCon's tunneling oxide layer technology and IBC back-side electrode arrangement are combined, resulting in significantly improved passivation and open-circuit voltage, achieving higher cell conversion efficiency while maintaining economic viability. The complete production process of TBC cells mainly includes depositing tunneling oxide and P+ polycrystalline silicon, depositing passivation films, and printing electrodes on the back of the silicon wafer. Based on the TOPCon production process, TBC cells require additional back-side electrode processes such as masking, laser grooving, PN region fabrication, and etching. Masking is mainly done using APCVD or PECVD, PN region fabrication is mainly done using PECVD, etching mainly uses traditional wet processing equipment, and grooving is performed using laser equipment.

[0064] For example, the back contact battery 10 is a hybrid BC battery, such as... Figure 9 As shown, the back contact battery 10 includes a substrate 101. In the third direction Z, one side of the substrate 101 is covered with a passivation layer 102 and an antireflection layer 103, with the passivation layer 102 located between the antireflection layer 103 and the substrate 101. The other side of the substrate 101 has a tunneling oxide layer 104, an N-type polycrystalline silicon layer 105, an intrinsic amorphous silicon layer 106, a P-type amorphous silicon layer 107, and a transparent conductive layer 108. The tunneling oxide layer 104 is located on the substrate. Between the N-type polycrystalline silicon layer 101 and the N-type polycrystalline silicon layer 105, the intrinsic amorphous silicon layer 106 is located on the side of the N-type polycrystalline silicon layer 105 away from the substrate 101, and the P-type amorphous silicon layer 107 is located between the intrinsic amorphous silicon layer 106 and the transparent conductive layer 108. The transparent conductive layer 108 is provided with a first fine gate 31 and a second fine gate 32. At this time, the first fine gate 31 is the negative electrode fine gate of the back contact battery 10, and the second fine gate 32 is the positive electrode fine gate of the back contact battery 10.

[0065] The side with the passivation layer 102 and the anti-reflection layer 103 is the front side of the substrate 101, which is the light-facing side facing the sunlight during the use of the back contact battery 10, and the other side is the back side of the substrate 101, which is the back-facing side facing away from the sunlight during the use of the back contact battery 10.

[0066] based on Figure 9 The back contact battery 10 shown is exemplarily prepared by the following method: First, the substrate 101 is cleaned and polished to obtain a clean and flat substrate surface. Then, a tunneling oxide layer 104 and intrinsic amorphous silicon are sequentially prepared on the back side of the substrate 101. The intrinsic amorphous silicon is then converted into a phosphorus-doped N-type polycrystalline silicon layer 105 for collecting electrons by high-temperature phosphorus diffusion.

[0067] Next, photoresist is coated on the N-type polysilicon layer 105 to form a mask, and the position of the P-region on the back side is determined by patterned etching. The N-type polysilicon layer 105 of the P-region is removed, and then the remaining mask and the surface phosphosilicate glass are removed, thereby forming an interdigitated structure with alternating N-regions and P-regions on the back side.

[0068] Next, the front side of the substrate 101 is acid-washed to remove impurities or oxide layers that may have been deposited on the front side in the previous process. Then, the front and back sides are textured on both sides to form a pyramid textured structure to enhance the light trapping effect.

[0069] Subsequently, hydrogen-containing passivation layers are deposited simultaneously on both the front and back sides. The passivation layer deposited on the front side, together with the alumina / silicon nitride stack, forms the final passivation layer 102 and antireflection layer 103. The hydrogen-containing passivation layer deposited on the back side serves as a temporary protective layer to protect the N-type polysilicon layer 105 on the back side in subsequent processes. This temporary protective layer is removed in a subsequent cleaning process. Afterward, an alumina and silicon nitride stack is deposited on the front side as the passivation layer 102 and antireflection layer 103, and the wraparound coating formed on the back side during the deposition process is removed using a chain wet process.

[0070] Then, an intrinsic amorphous silicon layer 106 and a P-type amorphous silicon layer 107 are sequentially deposited on the back side. The intrinsic amorphous silicon layer 106 serves as a back passivation layer, and the P-type amorphous silicon layer 107 serves as a hole collection layer. Subsequently, the intrinsic amorphous silicon layer 106 and the P-type amorphous silicon layer 107 on the N-region are removed using a patterned method, exposing the N-type polycrystalline silicon layer 105 in the N-region, while the stacked structure of the intrinsic amorphous silicon layer 106 and the P-type amorphous silicon layer 107 is retained in the P-region. Afterward, the film layer in the P-region is post-treated by laser thermal treatment to improve its crystallinity, doping activation degree, and contact performance. Finally, the natural oxide layer or contaminated oxide layer generated on the back side during laser treatment and previous processes is removed using a chain wet process.

[0071] Next, a transparent conductive layer 108 is deposited over the entire back surface and patterned to separate it into mutually insulated N-region and P-region conductive regions, which are used to collect electrons and holes, respectively. Silver paste is then printed and sintered on the N-region and P-region conductive regions to form a first fine grid 31 (negative electrode fine grid) and a second fine grid 32 (positive electrode fine grid), completing the electrode fabrication. An electro-injection test is then performed to preliminarily assess the battery performance.

[0072] Finally, insulating adhesive is printed locally on the first fine grid 31 and the second fine grid 32 to form the separator 4 in the above embodiment, and the main grid 2 and the harpoon structure 5 are printed on the back side to complete the overall fabrication of the back contact battery 10.

[0073] Based on the back contact battery 10 in any of the above embodiments, this application also provides a back contact stacked battery 20, such as... Figure 10As shown, the back-contact stacked solar cell 20 includes a back-contact bottom cell 201 and a perovskite top cell 202, with the perovskite top cell 202 electrically connected to the light-facing surface of the back-contact bottom cell 201. The back-contact bottom cell 201 can be the back-contact cell 10 described above.

[0074] The perovskite top-mounted solar cell 202 is a thin-film solar cell using perovskite material as the photoactive layer. The structure of the perovskite top-mounted solar cell 202 mainly consists of the following key components: a transparent conductive body, an electron transport layer, a perovskite light-absorbing layer, a hole transport layer, and a metal electrode. These components work together to enable the perovskite top-mounted solar cell 202 to effectively absorb sunlight and convert it into electrical energy. The perovskite material in the light-absorbing layer has excellent light absorption performance, absorbing a wider spectral range and effectively converting short-wavelength spectra, giving the perovskite top-mounted solar cell 202 high photoelectric conversion efficiency.

[0075] This application also provides a photovoltaic module, such as... Figure 11 and Figure 12 As shown, the photovoltaic module includes multiple photovoltaic cells and solder ribbon 30. Figure 11 The photovoltaic cell is illustrated as the back contact cell 10 in the above embodiment. Figure 12 The photovoltaic cell is illustrated as a back-contact tandem cell 20 in the above embodiment. The main grids 2 of two adjacent photovoltaic cells along the second direction Y are connected by solder strips 30.

[0076] The photovoltaic module also includes a front panel 40, a front encapsulation layer 50, a back encapsulation layer 60, and a backsheet 70. The front panel 40 and the backsheet 70 together sandwich the front encapsulation layer 50, photovoltaic cells, solder ribbons 30, and back encapsulation layer 60, and form a photovoltaic module through lamination. The front encapsulation layer 50 protects the light-facing side of the photovoltaic cells, and the back encapsulation layer 60 protects the back-facing side of the photovoltaic cells. During the lamination process, the front encapsulation layer 50 and the back encapsulation layer 60 encapsulate and protect the photovoltaic cells and solder ribbons 30, preventing external environmental factors from affecting their performance. They also bond the front panel 40, backsheet 70, photovoltaic cells, and solder ribbons 30 into a single unit.

[0077] The front panel 40 and the back panel 70 can be made of one of the following rigid materials: tempered glass, polyethylene terephthalate (PET), polycarbonate (PC), etc., or one of the following flexible materials: polyvinyl fluoride (PVF), ethylene-tetrafluoroethylene copolymer (ETFE), polyvinylidene fluoride (PVDF).

[0078] The front encapsulation layer 50 and the back encapsulation layer 60 are adhesive films. The material of the adhesive film can be one of the following: EVA (Ethylene-VinylAcetate Copolymer), POE (Polyolefin Elastomer), PVB (Polyvinyl Butyral). The front encapsulation layer 50 and the back encapsulation layer 60 can also be EPE adhesive film (EVA-POE-EVA co-extrusion structure) or EP adhesive film (EVA-EP co-extrusion structure).

[0079] For the same or similar parts among the various embodiments in this specification, please refer to each other.

Claims

1. A back-contact battery, characterized in that, The back contact battery includes: ontology; The first and second fine grids are disposed on the body, both extending along a first direction and arranged along a second direction, the first and second directions intersecting each other; A harpoon structure disposed on the body, the harpoon structure contacting the first fine grid in the third direction; An isolator disposed on the body, wherein, in the third direction, at least a portion of the isolator's structure is located between the second fine grid and the harpoon structure.

2. The back contact battery according to claim 1, characterized in that, The isolation member includes a first isolation member, which includes a first isolation portion and a second isolation portion extending along the first direction. The first isolation portion and the second isolation portion respectively contact the harpoon structure, and the first isolation portion and the second isolation portion are arranged at intervals along the first direction.

3. The back contact battery according to claim 2, characterized in that, The harpoon structure includes a first harpoon line and a second harpoon line arranged at intervals along the first direction. The extension directions of the first harpoon line and the second harpoon line both intersect the first direction, and the first harpoon line and the second harpoon line form a fork area. The first isolation portion and the second isolation portion have a gap in the first direction, and the gap is located in the fork region.

4. The back contact battery according to claim 3, characterized in that, The first isolation member further includes a third isolation portion, which is located between the first isolation portion and the second isolation portion in the first direction.

5. The back contact battery according to claim 4, characterized in that, The number of the third isolation section is one, or at least two of the third isolation sections are arranged at intervals along the first direction.

6. The back contact battery according to claim 4, characterized in that, The first isolation member includes at least a first segment and a second segment arranged along the second direction, and both the first segment and the second segment include the first isolation part, the second isolation part and the third isolation part; The body includes an edge extending along the first direction, and in the second direction, the second segment is located between the first segment and the edge; The number of the third isolation parts in the first segment arranged in the first direction is N1, and the number of the third isolation parts in the second segment arranged in the first direction is N2, where N2 > N1.

7. The back contact battery according to any one of claims 3 to 6, characterized in that, The isolation element further includes a second isolation element, which is arranged along the second direction with the first isolation element, and the second isolation element extends along the first direction and penetrates the fork region.

8. The back contact battery according to claim 7, characterized in that, The first and second isolation members are arranged alternately along the second direction.

9. The back contact battery according to claim 8, characterized in that, In the second direction, the first separator is adjacent to the edge of the back contact battery.

10. A back-contact stacked battery, characterized in that, The back contact stacked battery includes: A back-contact bottom battery, wherein the back-contact bottom battery is configured as the back-contact battery according to any one of claims 1 to 9; A perovskite top cell, wherein the perovskite top cell is electrically connected to the light-facing surface of the back contact bottom cell.

11. A photovoltaic module, characterized in that, The photovoltaic module includes a cover plate, an encapsulation layer, and a cell layer. The cell layer includes at least one of a back-contact cell and a back-contact stacked cell. The back-contact cell is configured as the back-contact cell according to any one of claims 1 to 9, and the back-contact stacked cell is configured as the back-contact stacked cell according to claim 10.

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