Solar cell

Abstract

The utility model relates to the technical field of solar cells, and discloses a solar cell which is provided with a grid line area and a non-grid line area. The solar cell includes: a silicon substrate; the backlight surface is provided with a first backlight area and a second backlight area, the first backlight area corresponds to the grid line area in position, and the second backlight area corresponds to the non-grid line area in position; the patterned passivation contact structure comprises a dielectric layer and a doped polycrystalline silicon layer, the doped polycrystalline silicon layer is provided with a first surface deviating from one side of the dielectric layer, and a patterned area of the passivation contact structure corresponds to the grid line area in position; the first functional layer is arranged on the surface of the silicon substrate and the doped polycrystalline silicon layer corresponding to the second backlight area; the first electrode penetrates through the first functional layer and is in ohmic contact with the doped polycrystalline silicon layer; the flatness of the first surface is higher than that of the second backlight area. The solar cell can reduce the problem of film explosion of the first passivation layer and reduce the contact resistance between the doped polycrystalline silicon layer and the first electrode.

Description

Technical Field

[0001] The utility model relates to the technical field of solar cells, in particular to a solar cell. Background Art

[0002] For a solar cell with local passivated contacts, the solar cell has a doped polysilicon layer and a dielectric layer, and the two together form a passivated contact structure, which provides a good passivation effect for the solar cell. Although such a solar cell can effectively reduce the absorption of long-wavelength light of sunlight and improve the short-circuit current of the solar cell, when depositing functional layers such as a passivation layer, it is difficult for hydrogen in the functional layers such as the passivation layer to escape, increasing the degree of film bursting, which is not conducive to improving the photoelectric conversion performance and yield of the solar cell. Summary of the Utility Model

[0003] An embodiment of the utility model discloses a solar cell, which can effectively reduce the degree of film bursting of the first functional layer and reduce the contact resistance between the doped polysilicon layer and the first electrode.

[0004] An embodiment of the present application discloses a solar cell, the solar cell having a grid line area corresponding to the position of the first electrode and a non-grid line area outside the grid line area; the solar cell includes:

[0005] A silicon substrate, the silicon substrate including a light-receiving surface and a backlight surface disposed opposite to each other; wherein, the backlight surface has a first backlight area and a second backlight area, the first backlight area corresponding to the position of the grid line area, and the second backlight area corresponding to the position of the non-grid line area;

[0006] A patterned passivated contact structure, the passivated contact structure including a dielectric layer disposed close to the silicon substrate and a doped polysilicon layer disposed away from the silicon substrate, the doped polysilicon layer having a first surface on a side away from the dielectric layer, the patterned area of the passivated contact structure corresponding to the position of the grid line area;

[0007] A first functional layer, the first functional layer being disposed on the surface of the silicon substrate corresponding to the second backlight area and on the surface of the doped polysilicon layer;

[0008] The first electrode, the first electrode passing through the first functional layer and making an ohmic contact with the doped polysilicon layer;

[0009] Wherein, the flatness of the first surface is higher than the flatness of the backlight surface corresponding to the second backlight area.

[0010] Further, the first surface has a plurality of first microstructures recessed from the first surface, and the backlight surface corresponding to the second backlight region has a plurality of second microstructures recessed from the backlight surface. The ratio of the size of the first microstructures to the size of the second microstructures is 0.1:1 to 1:2.

[0011] Further, the size of any one of the first microstructures is 2 μm to 10 μm, and the size of any one of the second microstructures is 5 μm to 30 μm.

[0012] Further, the second backlight region further includes a first structure region and a second structure region, and both the first structure region and the second structure region have a plurality of the second microstructures;

[0013] Among them, the recessed depth of the second microstructures in the first structure region is greater than the recessed depth of the second microstructures in the second structure region.

[0014] Further, a plurality of the second microstructures are stacked, and the stacking degree of the plurality of the second microstructures in the first structure region is higher than the stacking degree of the plurality of the second microstructures in the second structure region.

[0015] Further, in the first structure region, a plurality of the second microstructures are stacked along a first direction to form a strip structure, and the first direction is the extending direction of the sub-grid of the first electrode or perpendicular to the extending direction of the sub-grid.

[0016] Further, along a direction perpendicular to the first direction, the first structure region and the second structure region are alternately arranged.

[0017] Further, the distance between adjacent strip structures is greater than or equal to 2 μm; and / or,

[0018] The length of the strip structure along the first direction is greater than 30 μm.

[0019] Further, along the extending direction of the sub-grid, the length of the passivation contact structure is 50 μm to 300 μm; and / or,

[0020] The height difference between the first backlight region and the second backlight region is H, and the H satisfies: 0 μm < H ≤ 6 μm.

[0021] Further, the light-receiving surface of the silicon substrate has a textured structure. The solar cell further includes a semiconductor layer and a second functional layer. The semiconductor layer is disposed on the textured structure, and the second functional layer is disposed on a surface of the semiconductor layer away from the silicon substrate. The solar cell further includes a second electrode, and the second electrode is disposed on a surface of the second functional layer facing away from the silicon substrate. The second electrode passes through the second functional layer and makes an ohmic contact with the semiconductor layer.

[0022] Compared with the prior art, the present application has at least the following beneficial effects:

[0023] The present application provides a solar cell. The backlight surface of the solar cell includes a first backlight region and a second backlight region. Among them, the position of the first backlight region corresponds to the position of the grid line region, and the position of the second backlight region corresponds to the position of the non-grid line region. The patterned region of the passivation contact structure corresponds to the position of the grid line region. Therefore, this local setting method can effectively reduce the absorption of long-wavelength light by the solar cell and improve the short-circuit current of the solar cell.

[0024] In addition, the passivation contact structure includes a dielectric layer disposed close to the silicon substrate and a doped polysilicon layer disposed away from the silicon substrate. The doped polysilicon layer includes a first surface on a side away from the dielectric layer. And a first electrode is disposed on the first surface of the doped polysilicon layer. Therefore, since the flatness of the first surface is higher than that of the second backlight region of the backlight surface, the contact tightness between the first surface and the first electrode is high, and there are fewer defects at the interface. This helps to improve the efficiency of carrier transport. When depositing the first functional layer on the second backlight region of the backlight surface, the contact tightness between the first functional layer and the backlight surface corresponding to the second backlight region is relatively small. Therefore, it helps the hydrogen in the first functional layer to escape and reduces the degree of film bursting, thereby improving the yield and efficiency of the solar cell.

[0025] In summary, adopting the solar cell of the present application can improve the short-circuit current while reducing the degree of film bursting of the first functional layer and reducing the contact resistance between the first electrode and the doped polysilicon layer, thereby improving the photoelectric conversion efficiency and yield of the solar cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0027] Figure 1 It is a schematic structural diagram of the solar cell provided by the embodiment of the present application;

[0028] Figure 2 is an enlarged view of area A in Figure 1 ;

[0029] Figure 3 is an electron microscope image of the first surface provided by an embodiment of the present application;

[0030] Figure 4 is an electron microscope image of the backlight surface corresponding to the second backlight area provided by an embodiment of the present application;

[0031] Figure 5 is a schematic diagram of the first microstructure provided by an embodiment of the present application;

[0032] Figure 6 is a 3D microscope topography image of the backlight of the first surface and the second backlight area provided by an embodiment of the present application;

[0033] Figure 7 is a 3D microscope topography image of the strip structure provided by an embodiment of the present application.

[0034] Icons: 1, silicon substrate; 11, first backlight area; 12, second backlight area; 12a, first structural area; 12b, second structural area; 121, second microstructure; 1211, strip structure; 2, passivated contact structure; 21, dielectric layer; 22, doped polysilicon layer; 221, first microstructure; 3, first functional layer; 4, first electrode; 5, semiconductor layer; 6, second functional layer; 7, second electrode. Detailed implementation manners

[0035] Next, the technical solutions in the embodiments of the present utility model will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts shall fall within the protection scope of the present utility model.

[0036] In the present utility model, the orientation or positional relationship indicated by terms such as "upper", "lower", "left", "right", "front", "rear", "top", "bottom", "inner", "outer", "middle", "vertical", "horizontal", "lateral", "longitudinal", etc. is based on the orientation or positional relationship shown in the accompanying drawings. These terms are mainly used to better describe the present utility model and its embodiments, and are not used to limit that the indicated devices, elements or components must have a specific orientation, or be constructed and operated in a specific orientation.

[0037] Moreover, in addition to being used to represent orientation or positional relationships, some of the above terms may also be used to represent other meanings. For example, the term "upper" may also be used to represent a certain attachment relationship or connection relationship in some cases. For those of ordinary skill in the art, the specific meanings of these terms in the present utility model can be understood according to specific circumstances.

[0038] In addition, terms such as "first", "second", etc. are mainly used to distinguish different devices, components or constituent parts (the specific types and structures may be the same or different), and are not used to indicate or imply the relative importance and quantity of the indicated devices, components or constituent parts. Unless otherwise specified, the meaning of "a plurality" is two or more.

[0039] The technical solution provided by the present utility model will be further described below in conjunction with embodiments and drawings.

[0040] For a solar cell with a passivated contact structure, although it has good passivation and doping effects and can effectively improve the photoelectric conversion efficiency of the solar cell, it has an absorption effect on long-wavelength sunlight, which is not conducive to the improvement of the short-circuit current of the solar cell and restricts the further improvement of the photoelectric conversion performance of the solar cell to a certain extent.

[0041] Among them, the short-circuit current value of the solar cell can be increased by thinning the doped polysilicon layer or patterning the passivated contact structure. When thinning the doped polysilicon layer, a chemical etching process method is often used. This process has great processing difficulty, poor stability, and may damage the internal structure of the doped polysilicon layer, resulting in an increase in internal defects and an increase in the carrier recombination probability. Compared with the thinning method, patterning the passivated contact structure has less process operation difficulty, higher stability, and can effectively avoid the problem of internal defects.

[0042] However, after the patterning process, part of the silicon substrate will be exposed, and the passivation layer in this area has a high tightness of contact with the surface of the silicon substrate, which will cause the hydrogen in the functional layers such as the passivation layer to be difficult to escape, increasing the degree of film bursting and being not conducive to the improvement of the photoelectric conversion efficiency and yield of the solar cell.

[0043] Based on the above problems, the embodiments of the present application provide a solar cell that can effectively reduce the film bursting problem generated when depositing functional layers such as the passivation layer, reduce the contact resistance between the first passivated contact structure and the doped polysilicon layer, and thus improve the photoelectric conversion performance and yield of the solar cell.

[0044] The embodiments of the present application disclose a solar cell, as Figures 1 to 4 shown, the solar cell has a grid line area corresponding to the position of the electrode and a non-grid line area outside the grid line area; the solar cell includes:

[0045] A silicon substrate 1, the silicon substrate 1 includes a light-receiving surface and a backlight surface arranged opposite to each other; wherein, the backlight surface has a first backlight region 11 and a second backlight region 12, the first backlight region 11 corresponds to the position of the gate line region, and the second backlight region 12 corresponds to the position of the non-gate line region;

[0046] A patterned passivated contact structure 2, the passivated contact structure 2 includes a dielectric layer 21 arranged close to the silicon substrate 1 and a doped polysilicon layer 22 arranged away from the silicon substrate 1, the doped polysilicon layer 22 has a first surface on the side away from the dielectric layer 21, and the patterned region of the passivated contact structure 2 corresponds to the position of the gate line region;

[0047] A first functional layer 3, the first functional layer 3 is disposed on the surface of the silicon substrate 1 corresponding to the second backlight region 12 and on the surface of the doped polysilicon layer 22;

[0048] A first electrode 4, the first electrode 4 passes through the first functional layer 3 and makes an ohmic contact with the doped polysilicon layer 22;

[0049] Wherein, the flatness of the first surface is higher than that of the backlight surface corresponding to the second backlight region 12.

[0050] In the solar cell disclosed in this application, since the passivated contact structure 2 is provided on the backlight surface corresponding to the gate line region, the passivated contact structure 2 can provide a good passivation effect, reduce the recombination of carriers, and can effectively reduce the absorption of long-wavelength light by the solar cell, thereby increasing the short-circuit current of the solar cell. In addition, since the passivated contact structure includes a dielectric layer close to the silicon substrate and a doped polysilicon layer away from the silicon substrate, wherein the doped polysilicon layer includes a first surface close to the dielectric layer, and the first surface makes an ohmic contact with the first electrode, therefore, the flatness of the first surface is set to be higher than that of the backlight surface corresponding to the second backlight region 12, so that the contact tightness between the first electrode 4 and the doped polysilicon layer 22 is relatively high, which is beneficial to reducing the contact resistance and improving the photoelectric conversion efficiency of the solar cell. And because the contact tightness between the first functional layer 3 and the silicon substrate 1 corresponding to the second backlight region 12 is relatively small, it helps the hydrogen in the first functional layer 3 to escape, thereby helping to reduce the film bursting degree of the first functional layer 3 and improving the photoelectric conversion efficiency of the solar cell.

[0051] It should be noted that the passivated contact structure 2 provides good interface passivation effect for the solar cell. Among them, the material of the dielectric layer 21 may include various dielectric materials, such as at least one of silicon oxide, magnesium fluoride, amorphous silicon, polycrystalline silicon, silicon carbide, silicon nitride, silicon oxynitride, aluminum oxide or titanium oxide. Preferably, the dielectric layer 21 is a silicon oxide layer formed of silicon oxide, because the silicon oxide layer has excellent passivation performance, can minimize the recombination loss of minority carriers on the surface of the silicon substrate, and is a film with excellent durability for subsequent high-temperature processes.

[0052] The dielectric layer 21, as a kind of barrier for electrons and holes, can combine with the doped polysilicon layer 22 to form a passivated contact structure to prevent minority carriers from passing through; the dielectric layer 21 can also have the function of pinhole channels, enabling the carriers in the solar cell to move freely. By heavily doping the doped polysilicon layer 22, it can achieve selective passage of majority carriers, which is beneficial to reducing the recombination loss of minority carriers; in addition, the dielectric layer 21 can be used as a diffusion barrier to prevent the conductive elements in the doped polysilicon layer 22 from diffusing into the silicon substrate 1. And controlling the thickness of the dielectric layer 21 to be 0.5 nm to 4 nm is beneficial to reducing the transport hindrance of carriers and improving the transport efficiency.

[0053] Moreover, the fact that the patterned area of the passivated contact structure 2 corresponds to the gate line area means that the orthographic projection position of the passivated contact structure 2 on the backlight surface is the same as or substantially the same as the orthographic projection position of the first electrode 4 on the backlight surface. That is: the width of the passivated contact structure 2 is the same as or substantially the same as the gate line width of the first electrode 4. It can be understood that the width of the passivated contact structure 2 can be slightly larger than the gate line width of the first electrode 4, so as to ensure that the first electrode 4 can still maintain good contact with the passivated contact structure 2 within a reasonable printing error range. In this case, the position of the patterned area of the passivated contact structure 2 and the gate line area should still be understood as corresponding.

[0054] Among them, the first functional layer 3 includes at least one of an aluminum oxide layer, a silicon nitride layer, and a silicon oxynitride layer. Using the above functional layer can passivate the defects on the backlight surface, thereby reducing carrier recombination and improving the photoelectric conversion efficiency of the solar cell.

[0055] Moreover, there are a plurality of first microstructures 221 recessed from the first surface on the first surface, and there are a plurality of second microstructures 121 recessed from the backlight surface on the backlight surface corresponding to the second backlight region 12. The ratio of the size of the first microstructure 221 to the size of the second microstructure 121 is 0.1:1 to 1:2.

[0056] Among them, the dimension refers to the longest side length of the polygon shape of the orthographic projection of the first microstructure 221 and the second microstructure 121 on the horizontal plane of the solar cell. The polygon shape includes structures such as rectangles, rhombuses, and parallelograms.

[0057] As Figure 5 shown, taking the structure of the orthographic projection of the first microstructure 221 on the horizontal plane as a rectangle as an example, the dimension of the first microstructure 221 refers to the longest side length of this rectangle. The meaning of the dimension of the second microstructure 121 is the same as that of the first microstructure 221, and will not be elaborated here.

[0058] Among them, since the dimensions of the first microstructure 221 and the second microstructure 121 are within this range, the contact area between the doped polysilicon layer 22 and the first electrode 4 can be effectively increased, the contact resistance can be reduced, the carrier transport effect can be improved, and it can ensure that the hydrogen in the first functional layer 3 can effectively escape, reducing the film bursting phenomenon of the first functional layer 3.

[0059] In addition, the flatness refers to the smoothness of the backlight surface of the silicon substrate, which is the quantification of parameters such as the depression depth and stacking degree of the microstructures. That is, the higher the flatness, the smaller the depression depth and the higher the dispersion of the microstructures. Refer back to Figure 3 and Figure 4 , Figure 3 which is the electron microscope image of the first surface, Figure 4 and Figure 3 is the electron microscope image of the backlight surface corresponding to the second backlight area. Among them, the flatness of the first surface is higher than that of the backlight surface corresponding to the second backlight area 12, that is, it means that Figure 4 the surface in Figure 3 has a higher flatness than the surface in Figure 4 . Specifically, Figure 4 the first microstructure 221 in Figure 4 has a smaller depression depth and a higher dispersion, while Figure 4 the second microstructure 121 in

[0060] Among them, the solar cell of the present application can be obtained by the following preparation method, or can also be obtained by other preparation methods, as long as the solar cell of the present application can be obtained, which is not limited here.

[0061] The specific preparation method includes the following steps:

[0062] Fabrication of the passivated contact structure 2: A dielectric layer 21, a doped amorphous silicon layer, and a mask layer are sequentially deposited on the silicon substrate 1 and then annealed. During the annealing process, the doped amorphous silicon layer becomes a doped polycrystalline silicon layer 22, activating the doping elements in the doped amorphous silicon layer to form effective doping and creating pores in the dielectric layer 21.

[0063] Patterning: The passivated contact structure 2 in the non-grid line region is processed using a laser to remove the mask layer in the non-grid line region. Then, a chemical etching method is used to remove the passivated contact structure 2 in the non-grid line region and form a second micro-structure 121 on the second backlight region 12. Finally, a hydrofluoric acid solution is used to remove the mask layer in the grid line region and form a first micro-structure 221 on the first surface.

[0064] The first functional layer 3 and the first electrode 4: The first functional layer 3 is deposited on the backlight surface of the silicon substrate 1, and the first electrode 4 is fabricated on the first functional layer 3 such that the first electrode 4 makes an ohmic contact with the doped polycrystalline silicon layer 22 through the first functional layer 3.

[0065] Furthermore, the size of any one of the first micro-structures 221 is 2 μm to 10 μm, and the size of any one of the second micro-structures 121 is 5 μm to 30 μm.

[0066] When the size of the first micro-structure 221 is within the above range, it can effectively increase the contact area between the doped polycrystalline silicon layer 22 and the first electrode 4, significantly reduce the contact resistance, and improve the carrier transport efficiency. When the size of the second micro-structure 121 is within the above range, it can ensure that the hydrogen in the first functional layer 3 can escape to a high degree, which helps to further reduce the film bursting phenomenon in the first functional layer 3 and improve the yield of the solar cell.

[0067] Furthermore, as Figure 6 shown, the second backlight region 12 further includes a first structural region 12a and a second structural region 12b, and both the first structural region 12a and the second structural region 12b have a plurality of second micro-structures 121;

[0068] Among them, the depression depth of the second micro-structure 121 in the first structural region 12a is greater than the depression depth of the second micro-structure 121 in the second structural region 12b.

[0069] The second micro-structures 121 in the first structural region 12a have a smaller degree of dispersion and a higher depression depth, while the second micro-structures 121 in the second structural region 12b have a higher degree of dispersion and a smaller depression depth, indicating that the flatness of the second structural region is higher, and the tightness of the contact between the first functional layer 3 and the second structural region 12b is higher, which is beneficial to reducing interface defects and recombination. The flatness of the first structural region 12a is poorer, and the tightness of the contact between the first functional layer 3 and the first structural region 12a is poorer, which helps the escape of hydrogen and reduces the degree of film bursting.

[0070] Among them, since a number of second microstructures are superimposed, and the superimposition degree of a number of second microstructures 121 in the first structure region 12a is higher than that of a number of second microstructures 121 in the second structure region 12b, the unevenness of the first structure region 12a is higher than that of the second structure region 12b. Therefore, the tightness of the contact between the first functional layer 3 and the first structure region 12a can be effectively reduced, which helps the hydrogen in the first functional layer 3 to escape, thereby reducing the degree of film explosion of the first functional layer 3.

[0071] It should be noted that when the second backlight region is processed by laser and chemical etching methods, the superimposition degree of the second microstructures 121 at this time depends on the overlapping degree of the laser spots during laser processing. When the overlapping degree of the spots is higher, the superimposition degree of the second microstructures is higher at this time. Therefore, by designing the size, shape and overlapping degree of the laser spots, second microstructures with different sizes, projection shapes and superimposition degrees can be obtained.

[0072] In addition, the superimposition includes complete superimposition and partial superimposition. Among them, complete superimposition means that one second microstructure 121 is completely superimposed on another second microstructure 121, and partial superimposition means that a partial region of one second microstructure 121 is superimposed on another second microstructure. Most of the second microstructures 121 in the second structure region 12b are in a dispersed state, and a small number of second microstructures 121 are in a state of complete superimposition and partial superimposition. Most of the second microstructures 121 in the first structure region 12a are in a state of complete superimposition and partial superimposition, and a small number of second microstructures 121 are in a dispersed state. Therefore, the superimposition degree of the second microstructures 121 in the first structure region 12a is higher than that of the second structure region 12b.

[0073] In an alternative embodiment, as Figure 7 shown, in the first structure region 12a, a number of second microstructures 121 are superimposed along the first direction to form a strip structure 1211, where the first electrode 4 is the extending direction of the sub-grid (refer to Figure 6 the X direction in

[0074] In another alternative embodiment, in the first structure region 12a, a number of second microstructures 121 are superimposed along the first direction to form a strip structure 1211, where the first direction is perpendicular to the extending direction of the sub-grid (refer to Figure 4 the Y direction in

[0075] Due to the existence of the strip structure 1211, the depth difference of the depressions of the second microstructures at different positions in the first structural region 12a is relatively small. Therefore, the force on the film layer of the first functional layer 3 during the deposition process is relatively uniform, avoiding the phenomenon of stress concentration and further reducing the degree of film bursting of the first functional layer 3.

[0076] Among them, the strip structure refers to the structure formed by partial superposition of several second microstructures 121 along the first direction.

[0077] Furthermore, in an optional implementation manner, the first direction is the extending direction of the sub-grid. Therefore, along the direction perpendicular to the extending direction of the sub-grid, the first structural region 12a and the second structural region 12b are alternately arranged; in another optional implementation manner, the first direction is perpendicular to the extending direction of the sub-grid. Therefore, along the extending direction of the sub-grid, the first structural region 12a and the second structural region 12b are alternately arranged.

[0078] Among them, by adopting the alternating arrangement method of the first structural region 12a and the second structural region 12b, when depositing the first functional layer 3 on the backlight surface, the force on the first functional layer 3 during the deposition process is regular. Therefore, the phenomenon of stress concentration is reduced to a high degree, which helps to reduce the degree of film bursting of the first functional layer 3, and ensures that the deposited first functional layer 3 has a good passivation effect, which helps to reduce the recombination of carriers and improve the photoelectric conversion efficiency of the solar cell.

[0079] Furthermore, when the distance between adjacent strip structures 1211 is greater than or equal to 2 μm, while ensuring the passivation effect of the first functional layer 3, the degree of film bursting of the first functional layer 3 is reduced.

[0080] In addition, since the length of the strip structure 1211 along the first direction is greater than 30 μm, it helps to reduce the tightness of the contact between the first functional layer 3 and the first structural region 12a, and reduces the degree of film bursting of the first functional layer 3.

[0081] Furthermore, along the extending direction of the sub-grid, the length of the passivation contact structure 2 is 50 μm to 300 μm. When the length of the passivation contact structure 2 is within this range, the passivation effect is good, and it can effectively increase the short-circuit current and improve the photoelectric conversion efficiency of the solar cell.

[0082] Furthermore, the height difference between the first backlight region 11 and the second backlight region 12 is H, and H satisfies: 0 μm < H ≤ 6 μm. When the height of H meets the above range, it can ensure that the doped polysilicon layer 22 on the second backlight region 12 is completely removed, effectively increasing the short-circuit current value of the solar cell and improving the performance of the solar cell.

[0083] Further, the light-receiving surface of the silicon substrate 1 has a textured structure. The solar cell further includes a semiconductor layer 5 and a second functional layer 6. The semiconductor layer 5 is disposed on the textured structure, and the second functional layer 6 is disposed on the surface of the semiconductor layer 5 away from the silicon substrate 1. The solar cell further includes a second electrode 7. The second electrode 7 is disposed on the surface of the second functional layer 6 facing away from the silicon substrate 1, and the second electrode 7 is in ohmic contact with the semiconductor layer 5 through the second functional layer 6.

[0084] The above has introduced in detail a solar cell disclosed in the embodiments of the present application. Specific examples are used herein to elaborate on the principle and implementation manner of the present application. The description of the above embodiments is only used to help understand the solar cell. At the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. A solar cell, characterized in that: The solar cell has a gridline region corresponding to the location of the first electrode and a non-gridline region outside the gridline region; the solar cell comprises: A silicon substrate, the silicon substrate comprising a light-receiving surface and a backlight surface arranged in opposite directions; wherein the backlight surface has a first backlight area and a second backlight area, the first backlight area corresponds to the position of the gate line area, and the second backlight area corresponds to the position of the non-gate line area; A patterned passivation contact structure, the passivation contact structure comprising a dielectric layer disposed close to the silicon substrate and a doped polysilicon layer disposed away from the silicon substrate, the doped polysilicon layer having a first surface away from a side of the dielectric layer, and a patterned region of the passivation contact structure corresponding to a position of the gate line region; a first functional layer, wherein the first functional layer is disposed on a surface of the silicon substrate and a surface of the doped polysilicon layer corresponding to the second backlight area; The first electrode is in ohmic contact with the doped polysilicon layer through the first functional layer; The flatness of the first surface is higher than the flatness of the backlight surface corresponding to the second backlight area.

2. The solar cell according to claim 1, characterized in that: The first surface has a plurality of first microstructures recessed in the first surface, and the backlight surface corresponding to the second backlight area has a plurality of second microstructures recessed in the backlight surface, and the ratio of the size of the first microstructure to the size of the second microstructure is 0.1:1 to 1:

2.

3. The solar cell according to claim 2, characterized in that: The size of any one of the first microstructures is 2 μm to 10 μm, and the size of any one of the second microstructures is 5 μm to 30 μm.

4. The solar cell according to claim 2, characterized in that: The second backlight area further includes a first structure area and a second structure area, and both the first structure area and the second structure area have a plurality of the second microstructures; Wherein, the recessed depth of the second microstructure in the first structural region is greater than the recessed depth of the second microstructure in the second structural region.

5. The solar cell according to claim 4, characterized in that: A plurality of the second microstructures are arranged in an overlapping manner, and an overlapping degree of the plurality of the second microstructures in the first structural region is higher than an overlapping degree of the plurality of the second microstructures in the second structural region.

6. The solar cell according to claim 4, characterized in that: In the first structural region, a plurality of the second microstructures are stacked along a first direction to form a strip structure, and the first direction is an extension direction of the secondary grid of the first electrode, or is perpendicular to the extension direction of the secondary grid.

7. The solar cell according to claim 6, characterized in that: The first structural regions and the second structural regions are arranged alternately along a direction perpendicular to the first direction.

8. The solar cell according to claim 6, characterized in that: The spacing between adjacent band structures is greater than or equal to 2 μm; and / or, The length of the strip-shaped structure along the first direction is greater than 30 μm.

9. The solar cell according to claim 1, characterized in that: Along the extension direction of the auxiliary gate, the length of the passivation contact structure is 50 μm to 300 μm; and / or, A height difference between the first backlight area and the second backlight area is H, and H satisfies: 0 μm<H≤6 μm.

10. The solar cell according to any one of claims 1 to 9, characterized in that: The light-receiving surface of the silicon substrate has a velvet structure, and the solar cell also includes a semiconductor layer and a second functional layer, the semiconductor layer is arranged on the velvet structure, and the second functional layer is arranged on a side surface of the semiconductor layer away from the silicon substrate; the solar cell also includes a second electrode, the second electrode is arranged on a side surface of the second functional layer away from the silicon substrate, and the second electrode passes through the second functional layer to make ohmic contact with the semiconductor layer.

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