Photovoltaic module

Abstract

The application provides a photovoltaic module, comprising a cell string, the cell string comprising a plurality of cell pieces, the cell piece comprising an N-type silicon substrate, the N-type silicon substrate having a first surface and a second surface, the first surface comprising first regions and second regions arranged alternately, the first regions being provided with a boron-doped polysilicon layer, the second surface comprising third regions and fourth regions arranged alternately, the third regions being provided with a tunneling oxide layer and a phosphorus-doped conductive layer; the cell piece having a first surface and a second surface, the cell piece comprising a first electrode arranged on the first surface and a second electrode arranged on the second surface; a plurality of first cell pieces and a plurality of second cell pieces are arranged alternately, the first surface of the first cell piece and the second surface of the second cell piece are located on the same side; the first electrode of the first cell piece and the second electrode of the adjacent second cell piece are connected through a solder strip, and the second electrode of the first cell piece and the first electrode of the adjacent second cell piece are connected through a solder strip, so that the photoelectric conversion efficiency and the output power of the photovoltaic module can be improved.

Description

Technical Field

[0001] This application relates to the field of photovoltaic technology, and more specifically to a photovoltaic module. Background Technology

[0002] Solar energy is an inexhaustible and renewable energy source for humankind. Photovoltaic modules are the core and most important component of a solar power generation system. Their function is to convert solar energy into electrical energy, which is then stored in batteries or used to power loads. Photovoltaic modules typically consist of cell strings, which are composed of multiple solar cells connected in series.

[0003] In existing battery strings, the spacing between two adjacent cells is relatively large, resulting in a small power generation per unit area of ​​the photovoltaic module and a low photoelectric conversion efficiency. Summary of the Invention

[0004] In view of this, this application provides a photovoltaic module to help solve the problem of low photoelectric conversion efficiency of photovoltaic modules in the prior art.

[0005] This application provides a photovoltaic module including a battery string comprising multiple battery cells. Each battery cell includes an N-type silicon substrate with a first and a second surface distributed opposite to each other along its thickness direction. The first surface includes alternating first and second regions, each with a boron-doped polycrystalline silicon layer. The second surface includes alternating third and fourth regions, each with a stacked tunneling oxide layer and a phosphorus-doped conductive layer. Each battery cell has a first and a second surface distributed opposite to each other along its thickness direction. The battery cell includes a first electrode disposed on the first surface, located only in the first region and electrically connected to the boron-doped polycrystalline silicon layer. The cell also includes a second electrode disposed on the second surface, the second electrode being located only in the third region and electrically connected to the phosphorus-doped conductive layer; the cell includes a first cell and a second cell, a plurality of first cells and a plurality of second cells being alternately arranged in the length direction of the cell string, and along the thickness direction of the cell string, the first surface of the first cell and the second surface of the second cell are located on the same side; the cell string also includes a solder strip, the first electrode of the first cell being electrically connected to the second electrode of the adjacent second cell through the solder strip, and the second electrode of the first cell being electrically connected to the first electrode of the adjacent second cell through the solder strip.

[0006] In one possible implementation, the spacing between any of the first solar cells and the adjacent second solar cell is less than 1 mm.

[0007] In one possible implementation, the solder strip includes a plurality of first solder strips spaced apart along the length of the battery string, wherein a first electrode of the first battery cell is connected to a second electrode of an adjacent second battery cell via the first solder strip; the solder strip also includes a plurality of second solder strips spaced apart along the length of the battery string, wherein a second electrode of the first battery cell is connected to a first electrode of an adjacent second battery cell via the second solder strip.

[0008] In one possible implementation, the first electrode includes a first main gate and a first sub-gate, and the second electrode includes a second main gate and a second sub-gate; the extension direction of the first solder strip is parallel to the extension directions of the first main gate and the second main gate, and the first solder strip is used to connect the first main gate of the first cell and the second main gate of the adjacent second cell; the extension direction of the second solder strip is parallel to the extension directions of the first main gate and the second main gate, and the second solder strip is used to connect the second main gate of the first cell and the first main gate of the adjacent second cell.

[0009] In one possible implementation, the battery cell is a gridless battery, the first electrode includes a first sub-grid, and the second electrode includes a second sub-grid; the extension direction of the first solder strip is perpendicular to the extension directions of the first sub-grid and the second sub-grid, and the first solder strip is used to connect the first sub-grid of the first battery cell and the second sub-grid of the adjacent second battery cell; the extension direction of the second solder strip is perpendicular to the extension directions of the first sub-grid and the second sub-grid, and the second solder strip is used to connect the second sub-grid of the first battery cell and the first sub-grid of the adjacent second battery cell.

[0010] In one possible implementation, the phosphorus-doped conductive layer can be one of a phosphorus-doped amorphous silicon layer, a phosphorus-doped monocrystalline silicon layer, or a phosphorus-doped polycrystalline silicon layer.

[0011] In one possible implementation, the first surface has a velvety texture; and / or, the second surface has a velvety texture.

[0012] In one possible implementation, the solar cell further includes a first passivation layer and a first antireflection layer, wherein the first passivation layer is disposed on the side of the boron-doped polycrystalline silicon layer away from the N-type silicon substrate and on the second region, and the first antireflection layer is disposed on the side of the first passivation layer away from the N-type silicon substrate.

[0013] In one possible implementation, the solar cell further includes a second passivation layer and a second antireflection layer, wherein the second passivation layer is disposed on the side of the phosphorus-doped conductive layer away from the tunneling oxide layer and on the fourth region, and the second antireflection layer is disposed on the side of the second passivation layer away from the N-type silicon substrate.

[0014] In one possible implementation, the photovoltaic module further includes: an encapsulation layer for covering the surface of the battery string; and a cover plate for covering the surface of the encapsulation layer away from the battery string.

[0015] In this application, multiple solar cells in a battery string are arranged with alternating front and back sides, allowing the solder ribbons to connect adjacent cells on the same side. This reduces the spacing between adjacent cells in the string, increasing the number of cells without increasing the overall area of ​​the photovoltaic module. This reduces the blank area in the photovoltaic module layout, increases the light-receiving area per unit area of ​​the battery string, and thus increases the power generation per unit area, thereby improving the photovoltaic module's photoelectric conversion efficiency and output power. Furthermore, the solar cells in this application employ a special structure with a boron-doped polycrystalline silicon layer in the first region and a phosphorus-doped conductive layer in the third region, enabling a near 100% bifaciality. This further enhances the photovoltaic module's photoelectric conversion efficiency and output power. Additionally, the same-side interconnection of the solder ribbons prevents bending, reducing the risk of solder ribbon detachment and stress concentration at the edges of the solder ribbons and cells. This improves the reliability of the photovoltaic module and extends its lifespan.

[0016] 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

[0017] 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.

[0018] Figure 1 This is a schematic diagram of the structure of the photovoltaic module provided in this application;

[0019] Figure 2 for Figure 1 A schematic diagram of the cross-sectional structure of the solar cell in the image;

[0020] Figure 3 for Figure 1 A schematic diagram of the battery string in the first embodiment;

[0021] Figure 4 for Figure 3 A top view of the battery string in the middle;

[0022] Figure 5 for Figure 3A top view of the battery string in the middle;

[0023] Figure 6 for Figure 1 A schematic diagram of the battery string in the second embodiment;

[0024] Figure 7 for Figure 6 A top view of the battery string in the middle;

[0025] Figure 8 for Figure 6 A top view of the battery string in the middle.

[0026] Figure label:

[0027] 100-battery string;

[0028] 200-Encapsulation layer;

[0029] 300-cover plate;

[0030] 10-cell battery;

[0031] 10A - First surface;

[0032] 10B - Second surface;

[0033] 10a - First Region;

[0034] 10b - Second Region;

[0035] 10c - Third Region;

[0036] 10d - Fourth Region;

[0037] 101 - First solar cell;

[0038] 102 - Second solar cell;

[0039] 20-Welding strip;

[0040] 201 - First welding strip;

[0041] 202 - Second welding strip;

[0042] 1-N type silicon substrate;

[0043] 1a - First page;

[0044] 1b - Second page;

[0045] 2-Boron-doped polycrystalline silicon layer;

[0046] 3-Phosphorus-doped conductive layer;

[0047] 4-Tunneling oxide layer;

[0048] 5 - First electrode;

[0049] 51 - First main gate;

[0050] 52 - First sub-grid;

[0051] 6-Second electrode;

[0052] 61 - Second main gate;

[0053] 62 - Second auxiliary gate;

[0054] 7a - First antireflective layer;

[0055] 7b - First passivation layer;

[0056] 8a - Second antireflective layer;

[0057] 8b - Second passivation layer. Detailed Implementation

[0058] 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.

[0059] 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.

[0060] 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.

[0061] 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.

[0062] This application provides a photovoltaic module, such as... Figure 1As shown, the photovoltaic module includes a cell string 100, an encapsulation layer 200, and a cover plate 300. The encapsulation layer 200 covers both sides of the cell string 100 along the thickness direction Z of the photovoltaic module, and the cover plate 300 covers the surface of the encapsulation layer 200 away from the cell string 100. The encapsulation layer 200 can be an organic encapsulation film such as ethylene-vinyl acetate copolymer (EVA), polyvinyl octene coelastomer (POE), polyethylene terephthalate (PET), or polyvinyl butyral (PVB). The cover plate 300 can be a light-transmitting cover plate such as a glass cover plate or a plastic cover plate. The surface of the cover plate 300 facing the encapsulation layer 200 can be an uneven surface to increase the utilization rate of incident light. The encapsulation layer 200 and the cover plate 300 ensure that the photovoltaic module has good mechanical strength, reducing the impact of hail, wind, and mechanical vibration. The encapsulation process can also improve the sealing performance of the photovoltaic module, enhancing its corrosion resistance and safety.

[0063] The photovoltaic module includes multiple cell strings 100 electrically connected in series and / or parallel, and each cell string 100 includes multiple cell cells 10 connected by solder strips 20. The cell cells 10 can be whole cells, two-piece cells, three-piece cells, or other forms of multi-piece cells; this embodiment does not impose any limitations on this.

[0064] The structure of the battery cell 10 in this embodiment is as follows: Figure 2 As shown, the solar cell 10 includes an N-type silicon substrate 1. The N-type dopant element in the N-type silicon substrate 1 can be one or a combination of pentavalent elements such as phosphorus, arsenic, or antimony. The N-type silicon substrate 1 has a first surface 1a and a second surface 1b that are relatively distributed along its thickness direction Z. The first surface 1a is specifically the light-facing surface of the N-type silicon substrate 1, that is, the side facing the light source and used to receive direct sunlight; the second surface 1b is specifically the back-facing surface of the N-type silicon substrate, that is, the side facing away from the light source and used to receive sunlight reflected from the ground. Both the first surface 1a and the second surface 1b can receive sunlight and convert light energy into electrical energy.

[0065] The first surface 1a includes an alternating first region 10a and a second region 10b. The first region 10a can specifically be a metallized region on the light-facing side, i.e., the region where the metal gate lines on the light-facing side are located. For those skilled in the art, the actual width of the first region 10a can be larger than the actual width of the metal gate lines. The second region 10b can specifically be a non-metallized region on the light-facing side, i.e., the region of the first surface 1a excluding the first region 10a. The first surface 1a is provided with a boron-doped polycrystalline silicon layer 2. The boron-doped polycrystalline silicon layer 2 has a different doping element type than the N-type silicon substrate 1, and it can form a PN junction with the N-type silicon substrate 1 as an emitter. This can improve the injection efficiency of photogenerated minority carriers, increase the open-circuit voltage of the solar cell 10, increase the short-circuit current of the solar cell 10, thereby improving the photoelectric conversion efficiency of the solar cell 10. Furthermore, doping with boron can improve the high-temperature resistance of the polycrystalline silicon layer, ensuring that the solar cell 10 maintains good electrical properties during high-temperature annealing. It also enhances the long-term stability of the polycrystalline silicon layer, thereby improving the reliability of the solar cell 10 and extending its lifespan. Figure 2 As shown, the boron-doped polycrystalline silicon layer 2 is only disposed in the first region 10a, which can reduce the parasitic absorption of incident light in the second region 10b, thereby increasing the absorption rate of incident light on the first surface 1a, and thus improving the efficiency of the solar cell 10 towards the light surface.

[0066] like Figure 2 As shown, along the thickness direction Z of the N-type silicon substrate 1, a first passivation layer 7a is further disposed on the surface of the boron-doped polysilicon layer 2 away from the N-type silicon substrate 1, and a first antireflection layer 7b is further disposed on the surface of the first passivation layer 7a away from the boron-doped polysilicon layer 2. The second region 10b also has a first passivation layer 7a and a first antireflection layer 7b stacked along the thickness direction Z of the N-type silicon substrate 1, with the surface of the first passivation layer 7a away from the first antireflection layer 7b covering the first surface 1a. The first passivation layer 7a in the first region 10a (the first passivation layer 7a on the surface of the boron-doped polysilicon layer 2) and the first passivation layer 7a in the second region 10b can be an integral structure, and the first antireflection layer 7b in the first region 10a and the first antireflection layer 7b in the second region 10b can be an integral structure. The first passivation layer 7a may include at least one of silicon nitride, silicon oxynitride, titanium oxide, and aluminum oxide, which can play a good passivation role, enhance the carrier concentration of the first surface 1a, increase the short-circuit current and open-circuit voltage of the solar cell 10, thereby improving the photoelectric conversion efficiency of the solar cell. The first antireflection layer 7b utilizes the thin-film interference principle to reduce light reflection and increase the incident rate of light into the first surface 1a. Specifically, the first antireflection layer 7b may be a silicon oxide layer or an aluminum oxide layer.

[0067] The second surface 1b includes alternating third regions 10c and fourth regions 10d. Specifically, the third region 10c can be a metallized area of ​​the backlight surface, i.e., the area where the metal gate lines of the backlight surface are located. For those skilled in the art, the actual width of the third region 10c can be larger than the actual width of the metal gate lines. Specifically, the fourth region 10d can be a non-metallized area of ​​the backlight surface, i.e., the area of ​​the second surface 1b excluding the third region 10c. Along the thickness direction Z of the N-type silicon substrate 1, moving away from the silicon substrate 1, a tunneling oxide layer 4 and a phosphorus-doped conductive layer 3 are sequentially disposed within the third region 10c. The stacked tunneling oxide layer 4 and phosphorus-doped conductive layer 3 can form a passivation contact structure, which can improve the electron collection efficiency of the phosphorus-doped conductive layer 3. Specifically, the tunneling oxide layer 4 may include at least one of silicon oxide, aluminum oxide, silicon nitride, silicon oxynitride, silicon carbide, or magnesium fluoride, amorphous silicon, and polycrystalline silicon. The lattice of the tunneling oxide layer 4 can be well matched with the lattice of the N-type silicon substrate 1, thereby chemically passivating the portion of the second surface 1b located in the third region 10c, reducing the recombination centers at the contact surface between the tunneling oxide layer 4 and the N-type silicon substrate 1, and thus reducing the recombination rate of charge carriers at the contact surface between the N-type silicon substrate 1 and the tunneling oxide layer 4. The phosphorus-doped conductive layer 3 may specifically be one of a phosphorus-doped amorphous silicon layer, a phosphorus-doped monocrystalline silicon layer, or a phosphorus-doped polycrystalline silicon layer, used to form a field passivation layer on the second surface 1b, which can reduce the minority carrier concentration, achieve selective transport of majority carriers, thereby reducing the carrier recombination rate, increasing the voltage of the solar cell 10, increasing the short-circuit current of the solar cell 10, and thus improving the photoelectric conversion efficiency of the solar cell 10. Furthermore, phosphorus doping can enhance the long-term stability of the doped conductive layer, thereby improving the reliability of the solar cell 10 and extending its service life. For example... Figure 2 As shown, the phosphorus-doped conductive layer 3 and the tunneling oxide layer 4 are only disposed in the third region 10c, which can reduce the parasitic absorption of incident light in the fourth region 10d, thereby increasing the absorption rate of incident light on the second surface 1b, and thus improving the efficiency of the back light surface of the solar cell 10.

[0068] like Figure 2As shown, along the thickness direction Z of the N-type silicon substrate 1, a second passivation layer 8a is further disposed on the surface of the phosphorus-doped conductive layer 3 away from the tunneling oxide layer 4, and a second antireflection layer 8b is further disposed on the surface of the second passivation layer 8a away from the phosphorus-doped conductive layer 3. The fourth region 10d also has a second passivation layer 8a and a second antireflection layer 8b stacked along the thickness direction Z of the N-type silicon substrate 1, with the surface of the second passivation layer 8a away from the second antireflection layer 8b covering the second surface 1b. The second passivation layer 8a in the third region 10c (the second passivation layer 8a on the surface of the phosphorus-doped conductive layer 3) and the second passivation layer 8a in the fourth region 10d can be an integral structure, and the second antireflection layer 8b in the third region 10c and the second antireflection layer 8b in the fourth region 10d can also be an integral structure. The second passivation layer 8a may include at least one of silicon nitride, silicon oxynitride, titanium oxide, and aluminum oxide, which can play a good passivation role, enhance the carrier concentration of the second surface 1b, and increase the short-circuit current and open-circuit voltage of the solar cell 10, thereby improving the photoelectric conversion efficiency of the solar cell. The second antireflection layer 8b utilizes the principle of thin-film interference to reduce light reflection and increase the incident rate of light into the second surface 1b. Specifically, the second antireflection layer 8b may be a silicon oxide layer or an aluminum oxide layer.

[0069] In one specific embodiment, the first surface 1a and / or the second surface 1b have a textured structure. When the first surface 1a has a pyramidal textured structure, the reflectivity of the first surface 1a to incident light can be reduced, and the light absorption and utilization rate of the first surface 1a can be increased, thereby increasing the light transmittance of the first surface 1a and thus improving the photoelectric conversion efficiency of the solar cell 10. Similarly, when the second surface 1b has a pyramidal textured structure, the reflectivity of the second surface 1b to incident light can be reduced, and the light absorption and utilization rate of the second surface 1b can be increased, further improving the photoelectric conversion efficiency of the solar cell 10 and also increasing the bifaciality of the solar cell 10. Moreover, the texturing process can enhance the mechanical strength and durability of the N-type silicon substrate 1, reduce performance degradation caused by surface defects, and thus improve the long-term stability and reliability of the solar cell 10.

[0070] Furthermore, if texturing is only applied to the first side 1a, the front of the solar cell 10 will have a matte dark blue or bluish-black finish, while the back will have a reflective light blue finish. If multiple solar cells 10 in a photovoltaic module are arranged with alternating front and back sides, the appearance will be less than aesthetically pleasing. However, when both the first side 1a and the second side 1b have a texturing structure, it ensures that the light-facing and back-facing sides of the solar cell 10 exhibit similar colors. Even if the solar cells 10 in a photovoltaic module are arranged with alternating front and back sides, the color consistency of the photovoltaic module can be maintained, thereby improving the aesthetics of the photovoltaic module.

[0071] like Figure 2As shown, the solar cell 10 has a first surface 10A and a second surface 10B that are relatively distributed along its thickness direction Z. The first surface 10A is specifically the light-facing surface of the solar cell 10, located on the same side as the first surface 1a of the N-type silicon substrate 1. The second surface 10B is specifically the backlight surface of the solar cell 10, located on the same side as the second surface 1b of the N-type silicon substrate 1. The solar cell 10 includes a first electrode 5 disposed on the first surface 10A and a second electrode 6 disposed on the second surface 10B. The first electrode 5 is specifically the positive electrode of the solar cell 10, and the second electrode 6 is specifically the negative electrode of the solar cell 6. The first electrode 5 is located in the first region 10a, and at least a portion of the structure of the first electrode 5 can penetrate the first antireflection layer 7b and the first passivation layer 7a and form an electrical connection with the boron-doped polycrystalline silicon layer 2. That is, the first electrode 5 and the boron-doped polycrystalline silicon layer 2 are only disposed in the first region 10a. The boron-doped polycrystalline silicon layer 2 can improve the conductivity, ensuring a good ohmic contact between the first electrode 5 and the N-type silicon substrate 1, thereby reducing the series resistance. The second electrode 6 is located in the third region 10c, and at least a portion of the structure of the second electrode 6 can penetrate the second antireflection layer 8b and the second passivation layer 8a and form an electrical connection with the phosphorus-doped conductive layer 3. That is, the passivation contact structure composed of the phosphorus-doped conductive layer 3 and the tunneling oxide layer 4 is only disposed in the third region 10c with the second electrode 6. The passivation contact structure ensures that the second electrode 6 and the N-type silicon substrate 1 form a good ohmic contact, thereby reducing the series resistance.

[0072] In this embodiment, the battery cell 10 includes a first battery cell 101 and a second battery cell 102, such as Figure 3 As shown, along the length direction X of the battery string 100, each battery string 100 includes a plurality of alternating first battery pieces 101 and a plurality of second battery pieces 102. Along the thickness direction Z of the battery string 100, the first surface 10A of the first battery piece 101 and the second surface 10B of the second battery piece 102 are located on the same side. That is, the placement directions of the first battery piece 101 and the second battery piece 102 are opposite. The first electrode 5 of the first battery piece 101 and the second electrode 6 of the adjacent second battery piece 102 are electrically connected by solder ribbons 20, and the second electrode 6 of the first battery piece 101 and the first electrode 5 of the adjacent second battery piece 102 are also electrically connected by solder ribbons 20. The solder ribbons 20 include a plurality of first solder ribbons 201 spaced apart along the length direction X of the battery string 100 and a plurality of second solder ribbons 201 spaced apart along the length direction X of the battery string 100. The first solder ribbons 201 and the second solder ribbons 202 are located on opposite sides of the thickness direction Z of the battery string 100. The first electrode 5 of the first battery cell 101 is connected to the second electrode 6 of the adjacent second battery cell 102 via a first solder strip 201, and the second electrode 6 of the first battery cell 101 is connected to the first electrode 5 of the adjacent second battery cell 102 via a second solder strip 202.

[0073] Specifically, such as Figure 3 As shown, taking a battery string 100 comprising 6 battery pieces 10 as an example, along the length direction X of the battery string 100, the first battery piece 10 is the first battery piece 101, with its first surface 10A facing upwards; the second battery piece 10 is the second battery piece 102, with its second surface 10B facing upwards; the third battery piece 10 is the first battery piece 101, with its first surface 10A facing upwards; the fourth battery piece 10 is the second battery piece 102, with its second surface 10B facing upwards; the fifth battery piece 10 is the first battery piece 101, with its first surface 10A facing upwards; and the sixth battery piece 10 is the second battery piece 101, with its second surface 10B facing upwards. The first electrode 5 of the first battery cell 10 and the second electrode 6 of the second battery cell 10 are electrically connected by the first solder ribbon 201; the first electrode 5 of the second battery cell 10 and the second electrode 6 of the third battery cell 10 are electrically connected by the second solder ribbon 202; the first electrode 5 of the third battery cell 10 and the second electrode 6 of the fourth battery cell 10 are electrically connected by the first solder ribbon 201; the first electrode 5 of the fourth battery cell 10 and the second electrode 6 of the fifth battery cell 10 are electrically connected by the second solder ribbon 202; and the first electrode 5 of the fifth battery cell 10 and the second electrode of the sixth battery cell 10 are electrically connected by the first solder ribbon 201, thereby forming a complete battery string 100.

[0074] It should be noted that when the battery string 100 includes a larger number of battery cells 10, they are all arranged in the same manner as described above. This embodiment does not limit the specific number of battery cells 10 in the battery string 100. The first battery cell 101 and the second battery cell 102 have the same internal structure, only their placement orientation is different.

[0075] In the photovoltaic module provided in this embodiment, the multiple cells 10 in the cell string 100 are arranged in an alternating front and back manner, so that the solder ribbons 20 can connect adjacent cells 10 in a same-side interconnection manner. This reduces the spacing between adjacent cells 10 in the cell string 100, thereby increasing the number of cells 10 in the cell string 100 without increasing the area of ​​the photovoltaic module. This reduces the blank area of ​​the photovoltaic module layout, increases the light-receiving area of ​​the cell string 100 per unit area, and thus increases the power generation per unit area of ​​the photovoltaic module, thereby improving the photoelectric conversion efficiency and output power of the photovoltaic module. Moreover, the cell 10 in this embodiment adopts a special structure with a boron-doped polycrystalline silicon layer 2 in the first region 10a and a phosphorus-doped conductive layer 3 in the third region 10c, so that the bifaciality of the cell can approach 100%, thereby further improving the photoelectric conversion efficiency of the photovoltaic module and thus increasing the output power of the photovoltaic module. In addition, the same-side interconnection of the solder ribbon 20 can prevent the solder ribbon 20 from bending, reduce the risk of the solder ribbon 20 desoldering, and also reduce the risk of stress concentration at the edge of the solder ribbon 20 and the cell 10, which is conducive to improving the reliability of the photovoltaic module and thus extending the service life of the photovoltaic module.

[0076] In this embodiment, since the multiple solar cells 10 in the battery string 100 are arranged with alternating front and back sides, the solder ribbon 20 can connect adjacent solar cells 10 in a same-side interconnection manner. That is, there are no traditional solder ribbon gaps between adjacent solar cells 10, which can reduce the spacing between adjacent solar cells 10. Specifically, the spacing between any first solar cell 101 and the adjacent second solar cell 102 is less than 1 mm. The spacing can be 0 mm, 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, or 1 mm. When the spacing is 0 mm, the solar cells 10 can be densely stacked, maximizing the power generation per unit area of ​​the photovoltaic module, thereby increasing the output power of the photovoltaic module.

[0077] It should be noted that since it is impossible to achieve an absolutely zero gap in practical applications, as long as the measured value is less than 0.1mm, it can be considered that the gap is equivalent to 0mm within the allowable error range of the measurement work.

[0078] In one specific embodiment, the battery cell 10 can be a battery cell with a main grid. The first electrode 5 includes a first main grid 51 and a first sub-grid 52, where the first main grid 51 is specifically a positive main grid and the first sub-grid 52 is specifically a positive sub-grid. The second electrode 6 includes a second main grid 61 and a second sub-grid 62, where the second main grid 61 is specifically a positive main grid and the second sub-grid 62 is specifically a negative sub-grid. The extension direction of the first solder ribbon 201 is parallel to the extension direction of the first main grid 51 and the second main grid 61, both being the length direction X of the battery string 100. The first solder ribbon 201 is used to connect the first main grid 51 of the first battery cell 101 and the second main grid 61 of the adjacent second battery cell 102. The extension direction of the second solder ribbon 202 is parallel to the extension direction of the first main grid 51 and the second main grid 61, both being the length direction X of the battery string 100. The second solder ribbon 202 is used to connect the second main grid 61 of the first battery cell 101 and the first main grid 51 of the adjacent second battery cell 102. Along the width direction Y of the battery string 100, the first surface 10A of the battery cell 10 includes a plurality of first main grids 51 spaced apart, and the second surface 10B of the battery cell 10 includes a plurality of second main grids 61 spaced apart. The number of first solder strips 201 and second solder strips 202 should be consistent with the number of first main grids 51 and second main grids 61, so as to ensure the effectiveness of the first solder strips 201 and second solder strips 202 in collecting current in the battery cell 10.

[0079] In another specific embodiment, the battery cell 10 can be a gridless battery cell, where the first electrode 5 includes only a first sub-grid 52, and the second electrode 6 includes only a second sub-grid 62. The extension direction of the first solder ribbon 201 is perpendicular to the extension directions of the first sub-grid 52 and the second sub-grid 62. The extension direction of the first solder ribbon 201 is the length direction X of the battery string 100, and the extension directions of the first sub-grid 52 and the second sub-grid 62 are the width direction Y of the battery string 100. The first solder ribbon 201 is used to connect the first sub-grid 52 of the first battery cell 101 and the second sub-grid 62 of the adjacent second battery cell 102. The extension direction of the second solder ribbon 202 is perpendicular to the extension directions of the first sub-grid 52 and the second sub-grid 62. The extension direction of the second solder ribbon 202 is the length direction X of the battery string 100, and the extension directions of the first sub-grid 52 and the second sub-grid 62 are the width direction Y of the battery string 100. The second solder ribbon 202 is used to connect the second sub-grid 62 of the first battery cell 101 and the first sub-grid 52 of the adjacent second battery cell 102. Along the length of the battery string 100, the first surface 10A of the battery cell 10 includes multiple first sub-grids 52 spaced apart, and the second surface 10B of the battery cell 10 includes multiple second sub-grids 62 spaced apart. When the first solder ribbon 201 and the second solder ribbon 202 are connected to the battery cell 10, they should form an electrical connection with each first sub-grid 52 or each second sub-grid 62 on the same battery cell 10. Moreover, along the width direction Y of the battery string 100, multiple first solder ribbons 201 and multiple second solder ribbons 202 can be provided to improve the current collection effect of the first solder ribbons 201 and the second solder ribbons 202 on the battery cell 10.

[0080] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A photovoltaic module, characterized in that, The device includes a battery string (100), which includes multiple battery cells (10). Each battery cell (10) includes an N-type silicon substrate (1). The N-type silicon substrate (1) has a first surface (1a) and a second surface (1b) that are distributed opposite to each other along its thickness direction. The first surface (1a) includes an alternating first region (10a) and a second region (10b). The first region (10a) is provided with a boron-doped polycrystalline silicon layer (2). The second surface (1b) includes an alternating third region (10c) and a fourth region (10d). The third region (10c) is provided with a stacked tunneling oxide layer (4) and a phosphorus-doped conductive layer (3). The solar cell (10) has a first surface (10A) and a second surface (10B) that are distributed opposite to each other along its thickness direction. The solar cell (10) includes a first electrode (5) disposed on the first surface (10A), the first electrode (5) being located only in the first region (10a) and electrically connected to the boron-doped polycrystalline silicon layer (2). The solar cell (10) also includes a second electrode (6) disposed on the second surface (10B), the second electrode (6) being located only in the third region (10c) and electrically connected to the phosphorus-doped conductive layer (3). The battery cell (10) includes a first battery cell (101) and a second battery cell (102). A plurality of first battery cells (101) and a plurality of second battery cells (102) are alternately arranged in the length direction of the battery string (100). Along the thickness direction of the battery string (100), the first surface (10A) of the first battery cell (101) and the second surface (10B) of the second battery cell (102) are located on the same side. The battery string (100) also includes a solder strip (20), wherein the first electrode (5) of the first battery cell (101) and the second electrode (6) of the adjacent second battery cell (102) are electrically connected through the solder strip (20), and the second electrode (6) of the first battery cell (101) and the first electrode (5) of the adjacent second battery cell (102) are electrically connected through the solder strip (20).

2. The photovoltaic module according to claim 1, characterized in that, The distance between any of the first battery cells (101) and the adjacent second battery cell (102) is less than 1 mm.

3. The photovoltaic module according to claim 1, characterized in that, The solder strip (20) includes a plurality of first solder strips (201) spaced apart along the length direction of the battery string (100), and the first electrode (5) of the first battery cell (101) is connected to the second electrode (6) of the adjacent second battery cell (102) through the first solder strip (201); The solder strip (20) also includes a plurality of second solder strips (202) spaced apart along the length of the battery string (100), and the second electrode (6) of the first battery cell (101) is connected to the first electrode (5) of the adjacent second battery cell (102) through the second solder strips (202).

4. The photovoltaic module according to claim 3, characterized in that, The first electrode (5) includes a first main gate (51) and a first sub-gate (52), and the second electrode (6) includes a second main gate (61) and a second sub-gate (62). The extension direction of the first solder strip (201) is parallel to the extension direction of the first main grid (51) and the second main grid (61). The first solder strip (201) is used to connect the first main grid (51) of the first battery cell (101) and the second main grid (61) of the adjacent second battery cell (102). The extension direction of the second solder strip (202) is parallel to the extension direction of the first main grid (51) and the second main grid (61). The second solder strip (202) is used to connect the second main grid (61) of the first battery cell (101) and the first main grid (51) of the adjacent second battery cell (102).

5. The photovoltaic module according to claim 3, characterized in that, The battery cell (10) is a gridless battery, the first electrode (5) includes a first sub-grid (52), and the second electrode (6) includes a second sub-grid (62). The extension direction of the first solder strip (201) is perpendicular to the extension direction of the first sub-gate (52) and the second sub-gate (62). The first solder strip (201) is used to connect the first sub-gate (52) of the first battery cell (101) and the second sub-gate (62) of the adjacent second battery cell (102). The extension direction of the second solder strip (202) is perpendicular to the extension direction of the first sub-gate (52) and the second sub-gate (62). The second solder strip (202) is used to connect the second sub-gate (62) of the first battery cell (101) and the first sub-gate (52) of the adjacent second battery cell (102).

6. The photovoltaic module according to claim 1, characterized in that, The phosphorus-doped conductive layer (3) is one of a phosphorus-doped amorphous silicon layer, a phosphorus-doped monocrystalline silicon layer, or a phosphorus-doped polycrystalline silicon layer.

7. The photovoltaic module according to claim 1, characterized in that, The first surface (1a) has a velvety texture; And / or, the second surface (1b) has a velvety structure.

8. The photovoltaic module according to claim 1, characterized in that, The battery cell (10) further includes a first passivation layer (7a) and a first antireflection layer (7b). The first passivation layer (7a) is disposed on the side of the boron-doped polycrystalline silicon layer (2) away from the N-type silicon substrate (1) and on the second region (10b). The first antireflection layer (7b) is disposed on the side of the first passivation layer (7a) away from the N-type silicon substrate (1).

9. The photovoltaic module according to claim 1, characterized in that, The solar cell (10) further includes a second passivation layer (8a) and a second antireflection layer (8b). The second passivation layer (8a) is disposed on the side of the phosphorus-doped conductive layer (3) away from the tunneling oxide layer (4) and on the fourth region (10d). The second antireflection layer (8b) is disposed on the side of the second passivation layer (8a) away from the N-type silicon substrate (1).

10. The photovoltaic module according to any one of claims 1-9, characterized in that, The photovoltaic module also includes: An encapsulation layer (200) is used to cover the surface of the battery string (100); A cover plate (300) is used to cover the surface of the encapsulation layer (200) away from the battery string (100).

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