Solar cell and photovoltaic module

Abstract

The invention provides a solar cell and a photovoltaic module, and relates to the technical field of photovoltaics. The solar cell includes: a silicon substrate; the transmission layer and the passivation anti-reflection layer are arranged on at least one of the first surface and the second surface of the silicon substrate in a stacked mode, and the transmission layer comprises a polycrystalline silicon doping layer; a polycrystalline silicon region and an amorphous silicon region are arranged in the polycrystalline silicon doping layer, and the amorphous silicon region is positioned at a part of the polycrystalline silicon doping layer, which is deviated from the silicon substrate; the passivation anti-reflection layer is provided with a plurality of openings; the amorphous silicon region is located between the passivation anti-reflection layer and the polycrystalline silicon region and is close to the opening; and the electrode is positioned on one side, deviating from the silicon substrate, of the opening position and is in contact with the amorphous silicon region. According to the invention, the amorphous silicon region can block carriers in the non-electrode region, so that the recombination between the polycrystalline silicon doping layer and the metal in the electrode can be reduced; the light trapping effect is better improved, and the cell performance is improved.

Description

Technical Field

[0001] The invention relates to the field of photovoltaic technology, in particular to a solar cell and a photovoltaic module. Background Art

[0002] During the metallization process of solar cells, it is sometimes necessary to open an opening in the passivation anti-reflection layer to remove the passivation anti-reflection layer in the electrode area to form an exposed contact window.

[0003] However, the recombination in existing solar cells is relatively serious, which affects the performance of the solar cells. Summary of the invention

[0004] The invention provides a solar cell and a photovoltaic module, aiming to solve the relatively serious compound problem in the existing solar cells.

[0005] A first aspect of the present invention provides a solar cell, comprising:

[0006] A silicon substrate; in the direction of the thickness of the silicon substrate, the silicon substrate has a first surface and a second surface opposite to each other;

[0007] a transmission layer, disposed on at least one of the first surface and the second surface, the transmission layer comprising a polysilicon doping layer; the polysilicon doping layer comprising a polysilicon region and an amorphous silicon region, the amorphous silicon region being located on a side of the polysilicon doping layer away from the silicon substrate;

[0008] A passivation anti-reflection layer is arranged on a side of the transmission layer away from the silicon substrate, and the passivation anti-reflection layer has a plurality of openings;

[0009] The amorphous silicon region is located between the passivation anti-reflection layer and the polysilicon region and adjacent to the opening;

[0010] The electrode is located at a side of the opening away from the silicon substrate and is in contact with the amorphous silicon region.

[0011] In the present application, the non-electrode region is located between the passivation anti-reflection layer and the polysilicon region and near the opening. Compared with the polysilicon doped layer, the conductivity of amorphous silicon is slightly weaker. The amorphous silicon region located between the passivation anti-reflection layer and the polysilicon region and near the opening can block the carriers in the non-electrode region, thereby reducing the recombination between the polysilicon doped layer and the metal in the electrode; in addition, compared with the polysilicon doped layer and the passivation anti-reflection layer, the refractive index of amorphous silicon is different from that of the above two, which can increase the path of light in the solar cell, reduce reflected light, better increase the light trapping effect, and improve the battery performance. In summary, in the present application, there is less recombination between the polysilicon doped layer and the metal in the electrode; in addition, the refractive index of amorphous silicon is different from that of the polysilicon doped layer and the passivation anti-reflection layer, which can increase the path of light in the solar cell, reduce reflected light, better increase the light trapping effect, and improve the battery performance.

[0012] Optionally, starting from the edge of the opening of the passivation anti-reflection layer along a direction parallel to the silicon substrate, a length of the amorphous silicon region is less than or equal to 6 μm.

[0013] Optionally, a gap containing a first hole is formed between the passivation anti-reflection layer and the transmission layer at the edge of the opening.

[0014] Optionally, starting from the edge of the opening of the passivation anti-reflection layer along a direction parallel to the silicon substrate, the length of the amorphous silicon region is greater than the length of the gap.

[0015] Optionally, the polysilicon doped layer further comprises: micron crystals and / or nano crystals; the micron crystals and / or nano crystals are closer to the silicon substrate than the amorphous silicon region.

[0016] Optionally, an orthographic projection of the micron-crystal and / or nano-crystal on the first surface at least partially overlaps with an orthographic projection of the opening on the first surface.

[0017] Optionally, a lattice fringe spacing in the micron crystal, the nano crystal and the polysilicon region is 0.01 nm to 1 nm.

[0018] Optionally, in the direction where the thickness of the silicon substrate is located, the thickness of the amorphous silicon region is 1 nm to 70 nm; and / or,

[0019] Along the direction from the passivation anti-reflection layer to the opening, the thickness of the amorphous silicon region increases.

[0020] Optionally, in the amorphous silicon region, the thickness at a first position is a first thickness, the thickness at a second position is a second thickness, the first position is different from the second position; the ratio of the difference between the first thickness and the second thickness to the first thickness is less than or equal to 60%.

[0021] Optionally, the transmission layer is exposed at a side of the opening away from the silicon substrate, and one or more protrusions are formed;

[0022] Optionally, one or more protrusions are formed on the portion of the transmission layer exposed in the opening and on a side facing away from the silicon substrate.

[0023] Optionally, the transmission layer has a plurality of second holes on a side of the portion exposed in the opening and facing away from the silicon substrate.

[0024] Optionally, an edge of the second hole forms a protrusion.

[0025] Optionally, an annular protrusion is formed on the edge of the second hole.

[0026] Optionally, the annular protrusion may be a closed ring or a non-closed ring;

[0027] The above-mentioned ring shape not only includes a circular ring shape in a strict geometric sense, but also may be a ring-like shape, and may have arc segments with different curvatures.

[0028] Optionally, the thickness of the amorphous silicon located on the protruding portion is greater than or equal to the thickness of the amorphous silicon located at other positions of the opening.

[0029] A second aspect of the present invention provides a method for preparing a solar cell, comprising:

[0030] Providing a silicon substrate; in a thickness direction of the silicon substrate, the silicon substrate has a first surface and a second surface opposite to each other;

[0031] Prepare a transmission layer on at least one of the first surface and the second surface, wherein the transmission layer includes a polysilicon doped layer;

[0032] A passivation anti-reflection layer is prepared on the side of the polysilicon doped layer away from the silicon substrate, and a laser is used to open a local position of the passivation anti-reflection layer to form a plurality of openings; the polysilicon doped layer comprises a polysilicon region and an amorphous silicon region, the amorphous silicon region is located at a part of the polysilicon doped layer away from the silicon substrate, and the amorphous silicon region is located between the passivation anti-reflection layer and the polysilicon region, and adjacent to the opening;

[0033] An electrode is formed at a side of the opening away from the silicon substrate, and the electrode is in contact with the amorphous silicon region.

[0034] According to a third aspect of the present invention, there is provided a photovoltaic assembly, comprising: an electrical connector and any one of the solar cells; the electrical connector is electrically connected to electrodes in at least two of the solar cells.

[0035] The above-mentioned solar cells and photovoltaic modules have the same or similar beneficial effects, which will not be described again here to avoid repetition. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative labor.

[0037] Figure 1 A partial structural schematic diagram of a solar cell in an embodiment of the present invention is shown;

[0038] Figure 2 , Figure 3 Two partial enlarged structural schematic diagrams of solar cells in embodiments of the present invention are shown;

[0039] Figure 4 A schematic diagram of a local TEM structure of a solar cell in an embodiment of the present invention is shown;

[0040] Figure 5 Another partially enlarged structural schematic diagram of a solar cell in an embodiment of the present invention is shown;

[0041] Figure 6 A partial SEM structural schematic diagram of a transmission layer in an embodiment of the present invention is shown;

[0042] Figure 7 A schematic structural diagram of a laser opening in an embodiment of the present invention is shown.

[0043] Description of the accompanying drawings:

[0044] 1-silicon substrate, 2-polysilicon doped layer, 3-tunneling oxide layer, 4-electrode, 41-seed layer, 42-slurry layer, 5-passivation anti-reflection layer, 6-opening, 7-gap, 8-laser, 71-first hole, 21-amorphous silicon region, 22-micron crystal and / or nano crystal, 23-polysilicon region, 24-protrusion, 9-second hole. DETAILED DESCRIPTION

[0045] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0046] The present invention provides a solar cell, referring to Figure 1 , the solar cell includes: a silicon substrate 1, a transmission layer, an electrode 4 and a passivation anti-reflection layer 5. In the thickness direction Q of the silicon substrate 1, the silicon substrate 1 has a first surface and a second surface opposite to each other. During the operation of the solar cell, the surface of the silicon substrate 1 that mainly receives light is its light-facing surface. In the thickness direction Q of the silicon substrate 1, the backlight surface and the light-facing surface are opposite to each other. Among the first surface and the second surface here, one surface can be the backlight surface of the silicon substrate 1, and the other surface can be the light-facing surface of the silicon substrate 1. For example, Figure 1 is a main schematic diagram of the backlight surface of the solar cell, Figure 1 The upper surface of the silicon substrate is the backlight surface of the silicon substrate. Figure 2 for Figure 1 A local enlarged schematic diagram of the middle opening position and its vicinity.

[0047] The transmission layer is disposed on at least one of the first surface and the second surface of the silicon substrate 1, and the transmission layer here may include a P-type transmission layer and / or an N-type transmission layer. The P-type transmission layer and the N-type transmission layer may both be located on the backlight side of the silicon substrate 1, or either the P-type transmission layer or the N-type transmission layer may be located on the backlight side of the silicon substrate 1, and the other may be located on the light-facing side of the silicon substrate 1. Figure 1 and Figure 2 , 2 in the attached drawings refers to the polysilicon doping layer. Figure 1 In the embodiment, an N-type polysilicon doping layer and a P-type polysilicon doping layer may be included. The transmission layer may include a polysilicon doping layer 2, a polysilicon region containing polysilicon in the polysilicon doping layer 2, and the thickness of the polysilicon doping layer 2 may be 50nm to 250nm. The direction of the thickness of the polysilicon doping layer 2 and the direction of the thickness mentioned in other structures in the present application are parallel to the thickness direction Q of the silicon substrate 1 unless otherwise specified. Whether the transmission layer includes other layers is not specifically limited. TEM image refers to a transmission electron microscope image.

[0048] Reference Figures 1 to 4 The polycrystalline silicon doped layer 2 also has an amorphous silicon region 21 . The amorphous silicon region 21 contains amorphous silicon. The amorphous silicon region 21 is located at a portion of the polycrystalline silicon doped layer 2 away from the silicon substrate 1 .

[0049] The passivation anti-reflection layer 5 is arranged on the side of the transmission layer such as the polysilicon doped layer 2 away from the silicon substrate. The passivation anti-reflection layer 5 can be arranged adjacent to the polysilicon doped layer 2. The passivation anti-reflection layer 5 has a plurality of openings 6. The number of the openings 6 in the passivation anti-reflection layer 5 is not specifically limited. Figures 1 to 4, the amorphous silicon region 21 is located below the opening 6, and at the same time, the amorphous silicon region 21 is also located between the passivation anti-reflection layer 5 and the polysilicon region, and is adjacent to the opening 6. It should be noted that in the thickness direction Q of the silicon substrate 1, the polysilicon region 23 is closer to the silicon substrate than the amorphous silicon region 21.

[0050] The electrode 4 is located at the side of the opening 6 away from the silicon substrate and in contact with the amorphous silicon region 21 to achieve current collection and conduction. Compared with the polysilicon doped layer 2, the amorphous silicon in the amorphous silicon region 21 is more resistant to acid corrosion. Therefore, the amorphous silicon region 21 located below the opening 6 and between the passivation anti-reflection layer 5 and the polysilicon region and adjacent to the opening 6 can protect the film layer under the amorphous silicon region 21, for example, it can protect the polysilicon doped layer 2, so that the film layer under it has better weather resistance during long-term service, thereby maintaining the reliability and stability of the solar cell during long-term service; moreover, the passivation anti-reflection layer 5 is located between the polysilicon region and adjacent to the opening 6, which is a non-electrolytic In the electrode region, compared with the polysilicon doped layer 2, the conductivity of amorphous silicon is slightly weaker. The amorphous silicon region 21 located between the passivation anti-reflection layer 5 and the polysilicon region and adjacent to the opening 6 can block the carriers in the non-electrode region, thereby reducing the recombination between the polysilicon doped layer 2 and the metal in the electrode 4; in addition, compared with the polysilicon doped layer 2 and the passivation anti-reflection layer 5, the amorphous silicon has a different refractive index from both of the above, which can increase the path of light in the solar cell, reduce reflected light, better increase the light trapping effect, and improve the battery performance. For example, the silicon nitride layer is the farthest from the silicon substrate in the passivation anti-reflection layer 5, and the refractive index of amorphous silicon is different from the refractive index of the silicon nitride layer and the polysilicon doped layer 2, so it can increase the path of light in the solar cell, reduce reflected light, better increase the light trapping effect, and improve the battery performance.

[0051] It should be noted that the electrode 4 here can be an N-type electrode or a P-type electrode. The electrode 4 can be a collector grid line, or can be a whole electrode structure including a collector grid line, which is not limited. The electrode 4 can be a whole layer structure, or, as shown in FIG. Figure 1 The electrode 4 is a multi-layer structure, and the electrode 4 may include a seed layer 41 and a slurry layer 42. The slurry layer 42 may be made of base metals, etc., which can reduce the cost of the solar cell.

[0052] It should be noted that the base metal here mainly refers to: does not contain silver, or contains a very small amount of silver. For example, the slurry layer here may include: a copper slurry layer, an aluminum slurry layer, or a slurry layer with a mass content of precious metals less than 50%, and the precious metal here may include silver. For example, the slurry layer here may be a silver-clad copper slurry layer, etc.

[0053] The seed layer 41 contains metal elements, and the metal elements can be selected from at least one of titanium (Ti), tungsten (W), chromium (Cr), nickel (Ni), cobalt (Co), molybdenum (Mo), tin (Sn), lead (Pb), palladium (Pd), copper (Cu), niobium (Nb), ruthenium (Ru), indium (In), zinc (Zn), tantalum (Ta), and vanadium (V). Specifically, the material of the seed layer 41 is selected from the above materials, and the resistance of the above materials, the barrier properties of the metal elements in the slurry layer 42, and other properties are more suitable for the seed layer. In particular, the material of the seed layer 41 is selected from nickel and / or zinc. On the first hand, nickel and zinc both have good contact properties; on the second hand, nickel and zinc basically do not penetrate into the silicon substrate, and the composite is less; on the third hand, nickel and zinc have a good barrier effect on the metal in the slurry layer 42 on the side away from the silicon substrate, which can prevent the metal in the slurry layer 42 from penetrating into the silicon substrate and reduce the composite. It should be noted that x in the above chemical formula is a number greater than 0. The paste layer 42 may contain base metals, thereby reducing the cost of the solar cell.

[0054] The passivation anti-reflection layer 5 mentioned in the present application can provide a good passivation anti-reflection effect, and its specific material is not limited. For example, the passivation anti-reflection layer 5 may include an aluminum oxide layer and a silicon nitride layer stacked, wherein the aluminum oxide layer is closer to the silicon substrate, the thickness of the aluminum oxide layer may be 4nm to 10nm, and the thickness of the silicon nitride layer may be 50nm to 150nm.

[0055] Figure 1 to Figure 2 In the figure, the direction indicated by M is the direction parallel to the silicon substrate, and the direction M parallel to the silicon substrate is perpendicular to the thickness direction Q of the silicon substrate. Figure 3 The leftmost position is an opening. Figure 2 , from the edge of the opening of the passivation anti-reflection layer along the direction parallel to the silicon substrate, or in other words, on one side of an opening 6, the length d1 of the amorphous silicon region 21 along the width of the opening in the direction away from the opening is less than or equal to 6μm, where d1 is greater than 0. Too large d1 may be detrimental to the transmission and collection of carriers. The opening 6 is usually formed by laser, and too large d1 may also cause greater laser damage. For example, referring to Figure 2 , starting from the edge of the opening of the passivation anti-reflection layer in a direction parallel to the silicon substrate, the length d1 of the amorphous silicon region 21 is approximately 2.4 μm. For another example, d1 may be 6 μm, 5.5 μm, 5.3 μm, 5 μm, 4.5 μm, 4 μm, 3.5 μm, 3 μm, 2.5 μm, 2.45 μm, 2.42 μm, 2.41 μm, 2.37 μm, 2.35 μm, 2.32 μm, 2.2 μm, 2.1 μm, 2 μm, 1.5 μm, 1 μm, 0.5 μm, or 0.2 μm.

[0056] It should be noted that, in the present application, the direction from the edge of the opening of the passivation anti-reflection layer along the direction parallel to the silicon substrate may be the direction from the opening to the passivation anti-reflection layer and parallel to the silicon substrate. Figure 2 In the figure, the left side of the opening 6, starting from the edge of the opening of the passivation anti-reflection layer along the direction parallel to the silicon substrate is M2; the right side of the opening 6, starting from the edge of the opening of the passivation anti-reflection layer along the direction parallel to the silicon substrate is M1. For another example, Figure 3 The opening is located at the far left, and the right side of the opening, starting from the edge of the opening of the passivation anti-reflection layer along the direction parallel to the silicon substrate, is M1.

[0057] Optional, see Figure 3 A gap 7 containing a first hole 71 is formed between the passivation anti-reflection layer and the transmission layer at the edge of the opening, or in other words, at the edge of the opening 6, along the aforementioned direction M1, a gap 7 containing a first hole 71 is provided between the polysilicon doped layer 2 and the passivation anti-reflection layer 5. The gap 7 and / or the first hole 71 here provide space for the gas escaping from the passivation anti-reflection layer 5, thereby avoiding film explosion, improving the passivation effect, and compensating for the damage caused by laser film opening.

[0058] For example, usually in the process of forming the passivation anti-reflection layer, hydrogen elements will be formed in the passivation anti-reflection layer. For example, when the material of the passivation anti-reflection layer includes aluminum oxide, in the process of depositing aluminum oxide, because water participates in the reaction, excess hydrogen will be generated. In the process of laser film opening of the passivation anti-reflection layer, hydrogen will escape from the passivation anti-reflection layer under the influence of heat, and the hydrogen escape process will cause film explosion, damage the passivation anti-reflection layer and the doped semiconductor layer, and affect the passivation effect. The gap 7 of the present application is located at the edge of the passivation anti-reflection layer close to the opening, which can provide space for hydrogen escape during the laser film opening process, thereby alleviating or avoiding film explosion, reducing the damage caused by laser film opening, and effectively ensuring the passivation effect of the solar cell. The gap 7 here is mainly formed due to the thermal influence of laser film opening. Specifically, the passivation anti-reflection layer in the unopened area near the edge of the opening is slightly lifted or the transmission layer has some micropores due to the pre-treatment erosion of the collector grid line 4, thereby forming the above-mentioned gap. The shape of the first hole here is not specifically limited.

[0059] Optional, see Figure 3, from the edge of the opening of the passivation anti-reflection layer along the direction parallel to the silicon substrate, the length of the amorphous silicon region 21 is greater than the length of the gap 7, or in other words, when the side view is obtained from the cross-section, on one side of the opening 6, the length of the amorphous silicon region 21 along the aforementioned direction M1 is greater than the length of the gap 7. That is to say, on one side of an opening 6, from the edge of the opening of the passivation anti-reflection layer along the direction parallel to the silicon substrate, the length of the amorphous silicon region 21 is greater than the gap 7. The greater the length of the amorphous silicon region 21, the greater the protective effect on the film layer below it, such as the polycrystalline silicon doped layer 2, so that the film layer below it has better weather resistance during long-term service, and maintains the reliability and stability of the solar cell during long-term service; moreover, it can further reduce the recombination between the polycrystalline silicon doped layer 2 and the metal in the electrode 4; in addition, the amorphous silicon region is larger, and the effect of increasing the travel path of light in the solar cell is better.

[0060] It should be noted that the length of the amorphous silicon region 21 from the edge of the opening of the passivation anti-reflection layer in the direction parallel to the silicon substrate is greater than the length of the gap 7, specifically, for one opening 6, on the opposite sides of the opening 6, the length of the amorphous silicon region 21 located on the side of the passivation anti-reflection layer 5 close to the silicon substrate from the edge of the opening of the passivation anti-reflection layer in the direction parallel to the silicon substrate is greater than the length of the gap on the corresponding side; or, on only any one side of the opposite sides of the opening 6, the length of the amorphous silicon region 21 from the edge of the opening of the passivation anti-reflection layer in the direction parallel to the silicon substrate is greater than the length of the gap on that side. On one side of an opening 6, the length of the amorphous silicon region 21 from the edge of the opening of the passivation anti-reflection layer in the direction parallel to the silicon substrate exceeds the length of the gap 7, and the specific size is not limited.

[0061] Figure 4 TEM image of the polysilicon doped layer below the opening 6 and at the position near the opening 6 on the side of the passivation anti-reflection layer 5 close to the silicon substrate. Figure 4 The polysilicon doped layer also has: micron crystals and / or nano crystals 22 (refer to Figure 6 2. The micron crystal refers to a crystal with a grain size of micrometer or submicrometer. The nanocrystal refers to a crystal with a grain size of nanometer. In the direction Q where the thickness of the silicon substrate 1 is located, the micron crystal and / or nanocrystal 22 is closer to the silicon substrate 1 than the amorphous silicon region 21. The conductivity of nanocrystalline silicon and / or microcrystalline silicon is higher than that of amorphous silicon, which can improve the transmission efficiency of carriers.

[0062] Optionally, the orthographic projection of the micron-crystal and / or nano-crystal 22 on the first surface at least partially overlaps with the orthographic projection of the opening on the first surface, which may mean: the orthographic projection of the micron-crystal and / or nano-crystal 22 on the first surface completely overlaps with the orthographic projection of the opening on the first surface, and the areas of the two orthographic projections are equal; or, the orthographic projection of the micron-crystal and / or nano-crystal 22 on the first surface covers the orthographic projection of the opening on the first surface and is larger than the orthographic projection of the opening on the first surface; or, the orthographic projection of the opening on the first surface covers the micron-crystal and / or nano-crystal 22. The orthographic projection of the opening on the first surface is larger than the orthographic projection of the micron-crystal and / or nano-crystal 22 on the first surface, or the orthographic projection of the micron-crystal and / or nano-crystal 22 on the first surface covers part of the orthographic projection of the opening on the first surface and is larger than the orthographic projection of the opening on the first surface; or the orthographic projection of the opening on the first surface covers part of the orthographic projection of the micron-crystal and / or nano-crystal 22 on the first surface and is larger than the orthographic projection of the micron-crystal and / or nano-crystal 22 on the first surface. Nanocrystalline silicon and / or microcrystalline silicon has higher conductivity than amorphous silicon, which can improve the carrier transmission efficiency.

[0063] The orthographic projection of the microcrystal and / or nanocrystal 22 on the first surface refers to the projection of the microcrystal and / or nanocrystal 22 on the first surface when the microcrystal and / or nanocrystal 22 is irradiated with light perpendicular to the first surface. The orthographic projection of the opening on the first surface is similar.

[0064] Optional, see Figure 4 The polysilicon doped layer 2 includes: a polysilicon region 23 (refer to Figure 4 (shown by the open dotted line in the figure), the polycrystalline silicon region 23 contains polycrystalline silicon. The lattice fringe spacing in the micron crystal, nano crystal and polycrystalline silicon region 23 is 0.01nm to 1nm. The lattice fringe spacing refers to the spacing between adjacent lattice fringe measured in the TEM image. Specifically, the change in the lattice fringe spacing in the micron crystal, nano crystal and polycrystalline silicon region 23 will cause the band structure to change, thereby affecting the behavior of the carriers, and will also affect their movement and recombination process. The lattice fringe spacing in the micron crystal, nano crystal and polycrystalline silicon region 23 is within the above range, which can increase the life of the carriers. At the same time, the absorption peak is higher, which is conducive to improving the photoelectric conversion efficiency and reducing the recombination. That is to say, the lattice fringe spacing in the micron crystal, nano crystal and polycrystalline silicon region 23 is within the above range, which is the result of a balance of at least three factors: the life of the carriers, the photoelectric conversion efficiency and the recombination.

[0065] For example, the lattice stripe spacing in the micron-crystal, nano-crystal and polycrystalline silicon regions 23 can be 0.01nm, 0.02nm, 0.05nm, 0.1nm, 0.15nm, 0.2nm, 0.25nm, 0.3nm, 0.31nm, 0.32nm, 0.33nm, 0.34nm, 0.35nm, 0.4nm, 0.45nm, 0.5nm, 0.55nm, 0.6nm, 0.65nm, 0.7nm, 0.75nm, 0.8nm, 0.85nm, 0.9nm, 0.95nm, and 1nm.

[0066] It should be noted that the lattice fringe spacing may be consistent or may increase from the micron crystal and / or nano crystal 22 to the polysilicon region 23. The lattice fringe spacing of the micron crystal and / or nano crystal 22 and the polysilicon region 23 may be 0.31 nm. The lattice fringe spacing in the micron crystal and nano crystal may refer to a lattice fringe spacing in the micron crystal and nano crystal, or an average value of multiple lattice fringe spacings, and the lattice fringe spacing of the polysilicon region 23 is similar.

[0067] Optional, see Figure 2 , in the direction Q where the thickness of the silicon substrate 1 is located, the thickness d2 of the amorphous silicon region 21 is 1nm to 70nm. In a solar cell, if the thickness of the amorphous silicon region 21 is greater than 70nm, the carrier transport capability will be affected. If the thickness of the amorphous silicon region 21 is less than 1nm, the barrier effect on recombination is poor. If the thickness d2 of the amorphous silicon region 21 is 1nm to 70nm, at least the optimal balance between the carrier transport capability and the barrier effect on recombination is achieved, which not only plays a good role in carrier transport, but also has a good barrier effect on recombination. For example, the average thickness of the amorphous silicon region 21 is about 15nm, and an amorphous silicon region with a thickness of 52.84nm may appear, which is mainly caused by the uneven energy of the laser. The location with greater laser energy has higher heat, which will form a thicker amorphous silicon layer.

[0068] For example, the thickness d2 at different positions in the amorphous silicon region 21 may be 8.38 nm, 13.04 nm, 12.18 nm, or, referring to Figure 4, the thickness d2 at different positions in the amorphous silicon region 21 may be 8.65nm, 12.01nm. For another example, the thickness d2 of the amorphous silicon region 21 may be 1nm, 2nm, 3nm, 4nm, 5nm, 6nm, 7nm, 8nm, 9nm, 10nm, 11nm, 12nm, 13nm, 14nm, 14.5nm, 15nm, 15.5nm, 16nm, 16.5nm, 17nm, 18nm, 18.99nm, 20nm, 26.76nm, 30nm, 31.05nm, 35nm, 40nm, 45nm, 50nm, 55nm, 60nm, 65nm, 70nm.

[0069] For another example, at the edge of the opening 6, the thickness d2 of the amorphous silicon region 21 may be 14nm, 14.5nm, 14.8nm, 15nm, 15.5nm, 16nm, 16.5nm, or 17nm. For another example, below the opening 6, the thickness d2 of the amorphous silicon region 21 may be 8nm, 9nm, 8.5nm, 9.5nm, 10nm, 10.5nm, 10.8nm, 11nm, 11.5nm, 11.8nm, 12nm, 12.5nm, 13nm, or 16nm.

[0070] for Figure 2 As shown in the opening 6, the right side of the opening 6 is shown in the opposite direction of the arrow M1 along the direction from the passivation anti-reflection layer to the opening or the direction close to the opening 6, and the left side of the opening 6 is shown in the opposite direction of the arrow M2 along the direction from the passivation anti-reflection layer to the opening or the direction close to the opening 6. Optionally, along the direction from the passivation anti-reflection layer to the opening, the thickness of the amorphous silicon region increases, which is in the direction close to the opening 6, and the thickness of the amorphous silicon region 21 on one side or both sides of the opening increases; the direction of the thickness is parallel to the direction Q of the thickness of the silicon substrate 1. On the one hand, the laser energy near the opening 6 is higher. When the opening 6 is subsequently subjected to wet treatment such as acid etching, the thicker amorphous region near the opening 6 can be more acid-resistant. The opening 6 and the position closer to the opening 6 are more easily exposed to the external environment, which can fully protect the polycrystalline silicon doped layer on the side close to the silicon substrate and the film layer under the amorphous silicon region. For example, the polycrystalline silicon doped layer can be protected, so that the film layer under it has better weather resistance during long-term service, thereby maintaining the reliability and stability of the solar cell during long-term service. On the other hand, the amorphous silicon in the non-electrode region away from the opening 6 is thinner. Since the parasitic absorption of amorphous silicon is more serious than that of the polycrystalline silicon doped layer, the parasitic absorption brought by amorphous silicon needs to be reduced as much as possible. Therefore, the thinner amorphous silicon has lower parasitic absorption, and at the same time, the amorphous silicon region with suitable thickness can obtain the aforementioned good technical effects.

[0071] It should be noted that the thickness of the amorphous silicon region increases along the direction from the passivation anti-reflection layer to the opening. The increase here is directed to the direction close to the opening 6. The thickness of the amorphous silicon region 21 has an overall increasing trend, and the increase method is not limited. For example, it can be a linear increase, an exponential increase, etc.

[0072] Optionally, in the amorphous silicon region 21: the thickness at the first position is the first thickness, the thickness at the second position is the second thickness, the first position is different from the second position, and the first position and the second position are both arbitrary positions in the amorphous silicon region 21; the difference between the first thickness and the second thickness, and the ratio of the first thickness is less than or equal to 60%, the thickness of each position of the amorphous silicon region 21 is basically the same, the opening 6 and the position closer to the opening 6 are more easily exposed to the external environment, the thickness of each position of the amorphous silicon region 21 is basically the same, and the polycrystalline silicon doped layer at each position close to the side of the silicon substrate can be fully protected, and the film layer under the amorphous silicon region can be protected, for example, the polycrystalline silicon doped layer can be protected, so that the film layer thereunder has better weather resistance during long-term service, thereby maintaining the reliability and stability of the solar cell during long-term service.

[0073] For example, in the amorphous silicon region 21, the difference between the first thickness and the second thickness and the ratio of the first thickness can be 0, 0.5%, 0.7%, 0.8%, 1%, 1.5%, 1.2%, 1.8%, 2%, 2.3%, 2.5%, 3%, 3.5%, 3.9%, 4%, 4.5%, 5%. For another example, in the amorphous silicon region 21 between the passivation anti-reflection layer 5 and the polysilicon region: the thickness at one position is 20nm, the thickness at another position is 18.99nm, the thickness at another position is 26.76nm, and the thickness at another position is 31.05nm. The thickness at each position in the amorphous silicon region 21 is basically within 30nm or 40nm, which is relatively uniform.

[0074] Optional, see Figure 5 and Figure 6 The transmission layer is exposed in the opening and on the side away from the silicon substrate, and one or more protrusions 24 are formed. The protrusions 24 here can be the tower base on the surface of the silicon substrate, or the ridge of the tower base, which causes the transmission layer to have a protrusion on the side away from the silicon substrate 1, or the transmission layer has a protrusion near the position corresponding to the tower base on the surface of the silicon substrate or the ridge of the tower base on the side away from the silicon substrate, or the protrusion here can be a protrusion formed by processing to form an opening, which is not limited. The seed layer 41 gathers at the protrusion, and then the position of the seed layer 41 is more likely to form a three-dimensional structure, rather than a two-dimensional structure, and the combination of the seed layer 41 and the slurry layer is more firm, and the contact performance is better.

[0075] The shape of the protrusion is not particularly limited. Figure 5 is a cross-sectional view of the transmission layer, where the cross section is a cross section formed by cutting the transmission layer along the direction of the thickness of the silicon substrate. Figure 5 The shape of the protrusion 24 on the left side is a columnar protrusion. Figure 5 The raised portion in the middle may be a dot-shaped raised portion. Figure 5 The raised portion on the right side may be an annular raised portion; for example, Figure 6 In the figure, the shape of the protrusion 24 is annular. It should be noted that Figure 5 and Figure 6 The shapes of the protrusions are not fully shown in the figure, and the shapes of the protrusions include but are not limited to the aforementioned columnar, dot-shaped, prismatic, and annular shapes. The annular protrusions here can be continuously distributed as a closed ring, or discontinuously distributed as a non-closed ring, and there is no limitation on this. The above-mentioned ring shape includes not only a circular ring shape in a strict geometric sense, but also a ring-like shape, and can have arc segments with different curvatures.

[0076] Optionally, the transmission layer includes a polysilicon doped layer 2, and the part of the polysilicon doped layer 2 exposed in the opening 6 is also formed with one or more protrusions 24 on the side facing away from the silicon substrate 1; the protrusion 24 here can be regarded as a cross-sectional view on an intermittent distribution, i.e. a non-closed annular protrusion, or can be regarded as a protruding portion appearing at a local position.

[0077] Optionally, the thickness of the amorphous silicon located on the protrusion is greater than or equal to the thickness of the amorphous silicon located at the rest of the opening, or in other words, the thickness of the amorphous silicon located on the protrusion 24 in the amorphous silicon region 21 is greater than or equal to the thickness of the amorphous silicon located at the rest of the opening 6; the direction of the thickness at a certain position on the protrusion 24 in the amorphous silicon region 21 is perpendicular to the tangent line at the position on the protrusion 24, and the thickness of the amorphous silicon located on the protrusion 24 in the amorphous silicon region 21 can be the thickness of the amorphous silicon at any position in the protrusion 24 in the amorphous silicon region 21, or the average value of the thickness of the amorphous silicon at multiple positions, and no specific limitation is made to this. The thickness of the amorphous silicon at the rest of the opening 6 in the amorphous silicon region 21 can be the thickness at any position in the opening 6 in the amorphous silicon region 21 except the protrusion, or the average value of the thickness at multiple positions, and no specific limitation is made to this. It should be noted that the method for determining the thickness referred to in the entire text can all refer to this method. In order to avoid repetition, the relevant parts will not be repeated.

[0078] Figure 6FIG. 1 is a top view of a local position of the transmission layer, showing that the protrusion 24 can be a ring-shaped protrusion, and the ring shape here can be continuously distributed, i.e., a closed ring, or discontinuously distributed, i.e., a non-closed ring. During the laser opening process, the energy of the laser is not uniform enough, and the energy of the laser acting at certain positions is high, causing the polysilicon doped layer 2 to explode at this place and form a second hole 9, and the portion around the second hole 9 will form the above-mentioned protrusion 24; for example, Figure 6 In the figure, for the two marked second holes 9, a non-closed protrusion 24 is formed around the second hole 9 on the left, and a closed protrusion 24 is formed around the second hole 9 on the right. In the amorphous silicon region 21: it is easier to form a three-dimensional structure at the protrusion 24, and the uniformly distributed non-two-dimensional layer structure increases the surface roughness, thereby making the bonding with the polysilicon doping layer 2 thereunder more solid, reducing recombination, and providing better protection for the polysilicon doping layer 2. SEM image refers to scanning electron microscope image.

[0079] Optionally, the portion of the polycrystalline silicon doped layer 2 exposed in the opening 6 is on a side away from the silicon substrate 1, and there is a flat portion between adjacent protrusions 24, that is, adjacent protrusions 24 are intermittently distributed; in the amorphous silicon region 21: the thickness of the amorphous silicon located on the protrusion 24 is greater than the thickness of the amorphous silicon located on the flat portion, specifically, the height of the protrusion 24 is greater than the height of the flat portion, therefore, in the amorphous silicon region 21: the thickness of the amorphous silicon located on the protrusion 24 is greater than the thickness of the amorphous silicon located on the flat portion, and the protrusion 24 is more easily in contact with the outside world, and in the amorphous silicon region 21: the thickness of the amorphous silicon located on the protrusion 24 is large, and the protrusion 24 can be covered as much as possible, thereby making the bonding with the polycrystalline silicon doped layer 2 thereunder more firm, and better protecting the polycrystalline silicon doped layer 2.

[0080] Optionally, in the amorphous silicon region 21, the thickness of the amorphous silicon on the protrusion 24 is 10nm to 300nm, and / or, in the amorphous silicon region, the thickness of the amorphous silicon on the flat portion is 9nm to 16nm. Specifically, in the amorphous silicon region 21, the thickness of the amorphous silicon on the protrusion 24 is too large, which is easy to break, reducing the contact effect between the polysilicon doping layer 2 and the metal in the electrode 4, and affecting the conductive performance; in the amorphous silicon region 21, the thickness of the amorphous silicon on the protrusion 24 is too small, which does not fully and sufficiently cover the film layer below it, and does not protect the film layer below it. The thickness of the amorphous silicon on the protrusion 24 in the amorphous silicon region 21 is 10nm to 300nm, which is the result of a balance between at least the above two aspects. In the amorphous silicon region 21, the amorphous silicon on the protrusion 24 is not easy to break, and the amorphous silicon on the protrusion 24 covers the film layer below it more fully and sufficiently, and has a good protective effect on the film layer below it. Similarly, in the amorphous silicon region 21: the thickness of the amorphous silicon located on the flat portion is too large and is easy to break, reducing the contact effect between the polysilicon doped layer 2 and the metal in the electrode 4 and affecting the conductive performance; in the amorphous silicon region 21: the thickness of the amorphous silicon located on the flat portion is too small, and the coverage of the film layer thereunder is not comprehensive and sufficient, and the protective effect on the film layer thereunder is insufficient; in the amorphous silicon region 21: the thickness of the amorphous silicon located on the flat portion is 9nm to 16nm, which is the result of a balance between at least the above two aspects; in the amorphous silicon region 21: the amorphous silicon located on the flat portion is not easy to break, and the amorphous silicon located on the flat portion covers the film layer thereunder more comprehensively and sufficiently, and has a good protective effect on the film layer thereunder.

[0081] For example, in the amorphous silicon region 21, the thickness of the amorphous silicon on the protruding portion 24 may be 10 nm, 50 nm, 100 nm, 80 nm, 120 nm, 100 nm, 150 nm, 180 nm, 200 nm, 220 nm, 250 nm, 270 nm, 275 nm, 290 nm, or 300 nm. For another example, in the amorphous silicon region 21, the thickness of the amorphous silicon on the flat portion may be 9 nm, 10 nm, 11 nm, 12.5 nm, 13 nm, 13.5 nm, 14 nm, 14.5 nm, 15 nm, 15.5 nm, or 16 nm.

[0082] Optionally, in the amorphous silicon region 21, the thickness of the portion located at the edge of the solar cell is greater than the thickness of the portion located at the geometric center of the solar cell; or, in the amorphous silicon region 21, the thickness of the portion located at the edge of the solar cell is equal to the thickness of the portion located at the geometric center of the solar cell; or, in the amorphous silicon region 21, the thickness of the portion located at the edge of the solar cell is less than the thickness of the portion located at the geometric center of the solar cell. Specifically, in the process of laser opening, due to different laser types and processes (parameters and / or steps), the laser may irradiate the middle part of the solar cell with higher energy, and the thickness of the amorphous silicon region appearing below the opening of the passivation anti-reflection layer at the geometric center of the solar cell may be greater. If the laser type is changed or the parameters or steps are adjusted, the thickness of the amorphous silicon region on the solar cell may be more uniform, or the thickness of the amorphous silicon appearing at the opening position at the edge of the solar cell may be greater.

[0083] The present application also provides a method for preparing a solar cell, comprising the following steps.

[0084] Step 101, providing a silicon substrate; in a thickness direction of the silicon substrate, the silicon substrate has a first surface and a second surface opposite to each other.

[0085] Here, there is no specific limitation on whether the first surface and the second surface are polished structures or suede structures.

[0086] Step 102: Prepare a transmission layer on at least one of the first surface and the second surface, wherein the transmission layer includes a polysilicon doped layer.

[0087] The transmission layer may be formed by LPCVD (low pressure chemical vapor deposition) or other methods, and the specific method for forming the transmission layer is not limited.

[0088] Step 103, preparing a passivation anti-reflection layer on the side of the polysilicon doped layer away from the silicon substrate and using laser opening in the passivation anti-reflection layer to form a plurality of openings; the polysilicon doped layer comprises a polysilicon region and an amorphous silicon region, the amorphous silicon region is located at a portion of the polysilicon doped layer away from the silicon substrate, and the amorphous silicon region is located between the passivation anti-reflection layer and the polysilicon region and adjacent to the opening.

[0089] There is no specific limitation on the preparation method of the passivation anti-reflection layer, and for example, deposition and the like can be used. Figure 7, a laser opening is performed at a local position of the passivation anti-reflection layer 5 using a concentrator 8. Under the action of the laser, the silicon crystals in the polysilicon doped layer 2 located below the opening 6 and at a position near the opening 6 on the side of the passivation anti-reflection layer 5 close to the silicon substrate change, forming an amorphous silicon region 21 containing amorphous silicon. The specific parameters of the laser are not limited. For example, a picosecond laser engraving process can be used to engrave and open the passivation anti-reflection layer according to the designed collector grid line pattern to form the required micron-level groove structure.

[0090] Step 104: forming an electrode at a side of the opening away from the silicon substrate, wherein the electrode contacts the amorphous silicon region.

[0091] There is no specific limitation on the specific preparation method of the electrode. For example, a seed layer 41 may be prepared first, and then a slurry may be screen-printed on the side of the seed layer away from the silicon substrate and dried to form a slurry layer 42. The slurry layer may be formed by low-temperature silver-coated copper slurry, low-temperature copper slurry, low-temperature nickel slurry, etc. The slurry layer uses low-temperature silver-free metallization technology, which not only avoids the price and supply disadvantages of silver paste products, but also saves resource consumption caused by high-temperature technology. At the same time, it can avoid the heat effect brought by high-temperature technology, which can effectively reduce production costs.

[0092] It should be noted that the solar cell and the preparation method thereof provided in the present application are applicable to whether the transmission layer is an N-type transmission layer or a P-type transmission layer.

[0093] The present application also provides a photovoltaic module, including any of the aforementioned solar cells. The photovoltaic module may also include a packaging film located on both sides of the solar cell, and other structures in the photovoltaic module are not specifically limited.

[0094] The present application also provides a photovoltaic module, including any of the aforementioned solar cells. The photovoltaic module may also include an electrical connector, where the electrical connector may play a role of conductive interconnection, for example, the electrical connector may be a welding strip or a conductive backplane, etc., and there is no specific limitation on the electrical connector. The electrical connector is electrically connected to the aforementioned electrodes in at least two of the aforementioned solar cells, where the electrical connector may be directly electrically connected to the aforementioned electrodes, or indirectly electrically connected, and there is no limitation on this. The electrical connector may electrically connect the positive polarity electrode in one of the two adjacent aforementioned solar cells to the negative polarity electrode in the other solar cell, to achieve conductive interconnection.

[0095] It should be noted that in the present application, the relevant parts among the photovoltaic module, the solar cell and the method for preparing the solar cell can be referenced to each other, and can achieve the same or similar beneficial effects. In order to avoid repetition, they will not be described here.

[0096] The present application is further explained below with reference to specific embodiments.

[0097] Example

[0098] In the first step, a silicon substrate is provided. The silicon substrate includes a backlight surface and a light-facing surface opposite to each other in a thickness direction Q thereof.

[0099] In the second step, a tunneling oxide layer 3 and a transmission layer are sequentially prepared on the backlight side of the silicon substrate, wherein the transmission layer includes a polysilicon doped layer 2, wherein the polysilicon doped layer 2 is farthest from the silicon substrate. The polysilicon doped layer 2 contains a polysilicon region.

[0100] The third step is to prepare a back passivation anti-reflection layer 5 on the side of the polysilicon doped layer 2 facing away from the silicon substrate.

[0101] Step 4: Refer to Figure 7 The passivation anti-reflection layer is engraved and opened according to the designed collector grid line pattern using a picosecond laser engraving process to form the required micron-level groove structure, that is, to form an opening. Under the action of the laser, the silicon crystals in the polysilicon doped layer 2 located below the opening 6 and between the passivation anti-reflection layer 5 and the polysilicon region near the opening 6 change, forming an amorphous silicon region 21 containing amorphous silicon.

[0102] In the direction Q where the thickness of the silicon substrate 1 is located, the polycrystalline silicon doped layer 2 also contains micron crystals and / or nano crystals 22, and the micron crystals and / or nano crystals 22 are located between the polycrystalline silicon region 23 and the amorphous silicon region 21, and the lattice fringe spacing in the micron crystals and / or nano crystals 22 and the polycrystalline silicon region 23 is about 0.31 nm. On one side of an opening 6, starting from the edge of the opening of the passivation anti-reflection layer along the direction parallel to the silicon substrate, or in other words, the length d1 of the amorphous silicon region 21 located on the side of the passivation anti-reflection layer 5 close to the silicon substrate along the width of the opening 6 in the direction away from the opening is about 2.42 μm; on one side of an opening, starting from the edge of the opening of the passivation anti-reflection layer along the direction parallel to the silicon substrate, or in other words, along the width of the opening in the direction away from the opening, there is a gap 7 between the transmission layer and the passivation anti-reflection layer, and on one side of an opening 6, starting from the edge of the opening of the passivation anti-reflection layer along the direction parallel to the silicon substrate, the length of the amorphous silicon region 21 is greater than the length of the gap 7; in the direction Q where the thickness of the silicon substrate 1 is located, the thickness d2 of the amorphous silicon region 21 is about 18 nm.

[0103] In the fifth step, a seed layer 41 and a slurry layer 42 are sequentially arranged on the side of the transmission layer at the opening away from the silicon substrate, and a busbar line and the like are arranged simultaneously. The slurry layer 42 is a base metal slurry layer, and the main materials in the seed layer 41 and the slurry layer of the busbar line are nickel (Ni). On one side of an opening, along the width direction M of the opening, there is a gap 7 between the transmission layer and the passivation anti-reflection layer, and the amorphous silicon region 21 and the seed layer 41 both extend into the gap 7. On one side of an opening 6, the length of the gap 7 along the direction parallel to the silicon substrate from the edge of the opening of the passivation anti-reflection layer is about 3 μm. Along the direction away from the silicon substrate: the seed layer 41 exceeds the adjacent passivation anti-reflection layer; the height of the portion of the seed layer 41 exceeding the adjacent passivation anti-reflection layer is about 500 nm.

[0104] In the embodiment, the structure preparation of the light-facing side of the silicon substrate is not limited. The structure of the backlight side of the silicon substrate in the solar cell formed in the embodiment is roughly similar to Figure 1 shown.

[0105] The solar cell formed in the embodiment achieves good contact performance between the metal and the silicon substrate under low temperature conditions (below 300°C, such as around 200°C), does not require high temperature furnace sintering, and the heat introduced into the solar cell is very small. The solar cell formed in the embodiment is measured under national standard conditions, where the contact resistance at the opening position is less than or equal to 0.6 mΩ×cm 2 , superior to solar cells in related technologies.

[0106] It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or device including the element.

[0107] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation modes, which are merely illustrative rather than restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the present invention and the claims, all of which are within the protection of the present invention.

Claims

1. A solar cell, characterized in that: include: Silicon substrate; In the direction of the thickness of the silicon substrate, the silicon substrate has a first surface and a second surface opposite to each other; a transmission layer, disposed on at least one of the first surface and the second surface, the transmission layer comprising a polysilicon doped layer, the polysilicon doped layer comprising a polysilicon region and an amorphous silicon region, the amorphous silicon region being located on a side of the polysilicon doped layer away from the silicon substrate; A passivation anti-reflection layer is arranged on a side of the transmission layer away from the silicon substrate, and the passivation anti-reflection layer has a plurality of openings; The amorphous silicon region is located between the passivation anti-reflection layer and the polysilicon region and adjacent to the opening; The electrode is located at a side of the opening away from the silicon substrate and is in contact with the amorphous silicon region.

2. The solar cell according to claim 1, characterized in that Starting from the edge of the opening of the passivation anti-reflection layer along a direction parallel to the silicon substrate, a length of the amorphous silicon region is less than or equal to 6 μm.

3. The solar cell according to claim 1, characterized in that A gap containing a first hole is formed between the passivation anti-reflection layer and the transmission layer at the edge of the opening.

4. The solar cell according to claim 3, characterized in that: Starting from the edge of the opening of the passivation anti-reflection layer along a direction parallel to the silicon substrate, the length of the amorphous silicon region is greater than the length of the gap.

5. The solar cell according to claim 1, characterized in that: The polysilicon doping layer further comprises: micron crystals and / or nano crystals; the micron crystals and / or nano crystals are closer to the silicon substrate than the amorphous silicon region.

6. The solar cell according to claim 5, characterized in that: The orthographic projection of the micron-crystal and / or nano-crystal on the first surface at least partially overlaps with the orthographic projection of the opening on the first surface.

7. The solar cell according to claim 5, characterized in that: The lattice fringe spacing in the micron crystal, the nano crystal, and the polysilicon region is 0.01 nm to 1 nm.

8. The solar cell according to claim 1, characterized in that In the direction where the thickness of the silicon substrate is located, the thickness of the amorphous silicon region is 1 nm to 70 nm; and / or, Along the direction from the passivation anti-reflection layer to the opening, the thickness of the amorphous silicon region increases.

9. The solar cell according to claim 1, characterized in that: In the amorphous silicon region, a thickness at a first position is a first thickness, a thickness at a second position is a second thickness, and the first position is different from the second position; A ratio of a difference between the first thickness and the second thickness to the first thickness is less than or equal to 60%.

10. The solar cell according to any one of claims 1 to 9, characterized in that: The transmission layer is exposed in the opening and is formed with one or more protrusions on a side away from the silicon substrate.

11. The solar cell according to claim 10, characterized in that The thickness of the amorphous silicon located on the protruding portion is greater than or equal to the thickness of the amorphous silicon located at other positions of the opening.

12. A photovoltaic module, characterized in that: include: An electrical connector and a solar cell as claimed in any one of claims 1 to 11; The electrical connector is electrically connected to electrodes in at least two of the solar cells.

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