Solar cell and preparation method thereof

Abstract

The present disclosure relates to the field of solar cells, and specifically provides a solar cell and a preparation method, aiming to solve the problem of high internal resistance of existing battery structures. To this end, the solar cell provided by the present disclosure includes a substrate, a front doped layer, a back doped layer, a front electrode and a back electrode, and the back doped layer includes a third doped layer and a fourth doped layer juxtaposed along a first direction and insulated from each other, wherein the third doped layer and the fourth doped layer have opposite doping types; the front electrode is electrically connected to the front doped layer, and the back electrode is electrically connected to the back doped layer. Carriers can be transmitted between the front doped layer and the fourth doped layer, and between the third doped layer and the fourth doped layer. The internal resistance of the solar cell is the resistance value of the transmission resistances of these two carrier transmission paths connected in parallel. Therefore, the internal resistance of the solar cell can be reduced, thereby improving the conversion efficiency of the solar cell.

Description

Technical Field

[0001] The present disclosure relates to the field of solar cells, and specifically provides a solar cell and a preparation method thereof. Background Art

[0002] Since the discovery of the "photovoltaic effect", photovoltaics have been developed for more than a hundred years. The photovoltaic industry and technology are becoming more and more mature. At present, various high-efficiency solar cell technologies are flourishing. For example, perc cells, passivated contact cells (TOPCON cells), heterojunction (Heterojunction Technology, HJT) cells, back contact (Back Contact) cells and other technologies, each has its own advantages and disadvantages. Among the above battery technologies, the internal resistance of the battery is relatively high, which makes it difficult to improve the conversion efficiency of the battery. Summary of the invention

[0003] The present disclosure aims to solve the problems of the prior art and provides a solar cell and a preparation method thereof.

[0004] In a first aspect, the present disclosure provides a solar cell, comprising: a substrate, comprising a first surface and a second surface opposite to the first surface; a front doped layer, arranged on one side of the first surface of the substrate; a back doped layer, arranged on one side of the second surface of the substrate, comprising a third doped layer and a fourth doped layer juxtaposed along a first direction and insulated from each other, wherein the doping type of the third doped layer is opposite to that of the fourth doped layer; a front electrode, electrically connected to the front doped layer; and a back electrode, electrically connected to the back doped layer.

[0005] In some exemplary embodiments, the front doped layer includes a first doped layer, and a third passivation layer and a first anti-reflection layer are sequentially disposed on a side of the first doped layer away from the substrate.

[0006] In some exemplary embodiments, the front doping layer includes a first doping layer, a first intrinsic passivation layer is disposed between the first doping layer and the substrate, and a first transparent conductive layer is disposed on a side of the first doping layer away from the substrate.

[0007] In some exemplary embodiments, the first doped layer is disposed on the entire surface; or, the orthographic projection of the front electrode on the substrate is located within the orthographic projection of the first doped layer on the substrate.

[0008] In some exemplary embodiments, the front doping layer includes a first doping layer and a second doping layer juxtaposed along a first direction and insulated from each other, and the first doping layer and the second doping layer have opposite doping types.

[0009] In some exemplary embodiments, the first doping layer and the second doping layer are disposed in the same layer.

[0010] In some exemplary embodiments, a first tunneling oxide layer is disposed between at least one of the first doping layer and the second doping layer and the substrate, and a first anti-reflection layer is disposed on a side away from the substrate.

[0011] In some exemplary embodiments, a first intrinsic passivation layer is disposed between at least one of the first doping layer and the second doping layer and the substrate, and a transparent conductive layer is disposed on a side away from the substrate.

[0012] In some exemplary embodiments, the front electrode includes a first electrode and a second electrode, the first electrode is electrically connected to the first doping layer, the second electrode is electrically connected to the second doping layer, a first passivation layer is disposed on one side of the first surface of the substrate, and at least one of the first electrode and the second electrode is electrically connected to the corresponding doping layer after penetrating the first passivation layer.

[0013] In some exemplary embodiments, the front electrode includes a first electrode and a second electrode, the first electrode is electrically connected to the first doped layer, the second electrode is electrically connected to the second doped layer, the orthographic projection of the first electrode on the substrate is within the orthographic projection range of the first doped layer on the substrate; and / or the orthographic projection of the second electrode on the substrate is within the orthographic projection range of the second doped layer on the substrate.

[0014] In some exemplary embodiments, the third doping layer and the fourth doping layer are disposed in the same layer.

[0015] In some exemplary embodiments, a second tunneling oxide layer is disposed between at least one of the third doping layer and the fourth doping layer and the substrate, and a second anti-reflection layer is disposed on a side away from the substrate.

[0016] In some exemplary embodiments, a second intrinsic passivation layer is disposed between at least one of the third doping layer and the fourth doping layer and the substrate, and a transparent conductive layer is disposed on a side away from the substrate.

[0017] In some exemplary embodiments, the back electrode includes a third electrode and a fourth electrode, the third electrode is electrically connected to the third doping layer, the fourth electrode is electrically connected to the fourth doping layer, a second passivation layer is provided on one side of the second surface of the substrate, and at least one of the third electrode and the fourth electrode is electrically connected to the corresponding doping layer after penetrating the second passivation layer.

[0018] In some exemplary embodiments, the back electrode includes a third electrode and a fourth electrode, the third electrode is electrically connected to the third doped layer, the fourth electrode is electrically connected to the fourth doped layer, the orthographic projection of the third electrode on the substrate is located within the orthographic projection range of the third doped layer on the substrate; and / or the orthographic projection of the fourth electrode on the substrate is located within the orthographic projection range of the fourth doped layer on the substrate.

[0019] In some exemplary embodiments, a material of the front doping layer or the back doping layer is one of amorphous silicon, microcrystalline silicon, polycrystalline silicon, single crystal silicon or a compound semiconductor.

[0020] In a second aspect, the present disclosure provides a method for preparing a solar cell, comprising: providing a substrate, the substrate comprising a first surface and a second surface opposite to the first surface; forming a front doping layer on one side of the first surface of the substrate; forming a back doping layer on one side of the second surface of the substrate, the back doping layer comprising a third doping layer and a fourth doping layer juxtaposed along a first direction and insulated from each other, wherein the third doping layer and the fourth doping layer have opposite doping types; forming a front electrode and a back electrode, the front electrode being electrically connected to the front doping layer, and the back electrode being electrically connected to the back doping layer.

[0021] In a third aspect, the present disclosure provides a solar cell assembly, comprising a plurality of solar cells connected in series and / or in parallel; the solar cell comprises: a substrate, comprising a first surface and a second surface opposite to the first surface; a front doped layer, disposed on one side of the first surface of the substrate; a back doped layer, disposed on one side of the second surface of the substrate, comprising a third doped layer and a fourth doped layer juxtaposed along a first direction and insulated from each other, wherein the doping type of the third doped layer is opposite to that of the fourth doped layer; a front electrode, electrically connected to the front doped layer; and a back electrode, electrically connected to the back doped layer.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The solar cell provided by the present disclosure includes a substrate, a front doping layer, a back doping layer, a front electrode and a back electrode, wherein the front doping layer is arranged on one side of the first surface of the substrate; the back doping layer is arranged on one side of the second surface of the substrate, and includes a third doping layer and a fourth doping layer juxtaposed along a first direction and insulated from each other, wherein the third doping layer and the fourth doping layer have opposite doping types; the front electrode is electrically connected to the front doping layer, and the back electrode is electrically connected to the back doping layer. Carriers can be transmitted between the front doping layer and the fourth doping layer, and between the third doping layer and the fourth doping layer. The internal resistance of the solar cell is the resistance value of the transmission resistances of these two carrier transmission paths connected in parallel, so the internal resistance of the solar cell can be reduced, thereby improving the conversion efficiency of the solar cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The preferred embodiments of the present disclosure are described below in conjunction with the accompanying drawings, in which:

[0025] Figure 1 is a first cross-sectional view of a solar cell provided by at least one embodiment of the present disclosure;

[0026] Figure 2 is a second cross-sectional view of a solar cell provided by at least one embodiment of the present disclosure;

[0027] Figure 3 is a third cross-sectional view of a solar cell provided by at least one embodiment of the present disclosure;

[0028] Figure 4 is a fourth cross-sectional view of a solar cell provided by at least one embodiment of the present disclosure;

[0029] Figure 5 is a fifth cross-sectional view of a solar cell provided by at least one embodiment of the present disclosure;

[0030] Figure 6 is a sixth cross-sectional view of a solar cell provided by at least one embodiment of the present disclosure;

[0031] Figure 7 is a seventh cross-sectional view of a solar cell provided by at least one embodiment of the present disclosure;

[0032] Figure 8 is an eighth cross-sectional view of a solar cell provided by at least one embodiment of the present disclosure;

[0033] Fig. 9 is a ninth cross-sectional view of a solar cell provided by at least one embodiment of the present disclosure;

[0034] Fig.10 This is the tenth cross-sectional view of a solar cell provided by at least one embodiment of the present disclosure.

[0035] Description of reference numerals:

[0036] 1. substrate; 101. first tunneling oxide layer; 2. first doped layer; 201. first passivation layer; 202. second passivation layer; 203. third passivation layer; 3. second doped layer; 41. first anti-reflection layer; 51. first intrinsic passivation layer; 61. first transparent conductive layer; 62. second transparent conductive layer; 7. third doped layer; 8. fourth doped layer; 102. second tunneling oxide layer; 42. second anti-reflection layer; 52. second intrinsic passivation layer; 63. third transparent conductive layer; 64. fourth transparent conductive layer; 91. first electrode; 92. second electrode; 93. third electrode; 94. fourth electrode. DETAILED DESCRIPTION

[0037] The preferred embodiments of the present disclosure are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present disclosure and are not intended to limit the protection scope of the present disclosure.

[0038] It should be noted that in the description of the present disclosure, the terms "upper", "lower", "left", "right", "inner", "outer" and the like indicating directions or positional relationships are based on the directions or positional relationships shown in the drawings, which are only for the convenience of description, and do not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present disclosure. In addition, the terms "first" and "second" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0039] In addition, it should be noted that in the description of the present disclosure, unless otherwise clearly specified and limited, the terms "installation", "setting", and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, an indirect connection through an intermediate medium, or the internal connection of two elements. For those skilled in the art, the specific meanings of the above terms in the present disclosure can be understood according to specific circumstances.

[0040] In order to solve the problem of high internal resistance of existing battery structures, the present disclosure provides a solar cell, comprising: a substrate, comprising a first surface and a second surface opposite to the first surface; a front doped layer, arranged on one side of the first surface of the substrate; a back doped layer, arranged on one side of the second surface of the substrate, comprising a third doped layer and a fourth doped layer juxtaposed along a first direction and insulated from each other, wherein the doping types of the third doped layer and the fourth doped layer are opposite; a front electrode, electrically connected to the front doped layer; and a back electrode, electrically connected to the back doped layer.

[0041] Next, the solar cell provided by the embodiment of the present disclosure is introduced.

[0042] Embodiment 1

[0043] The solar cell includes a substrate 1, the material of the substrate 1 is silicon, and the substrate 1 can be an N-type doped silicon substrate, or a P-type doped silicon substrate. The substrate 1 includes a first surface and a second surface opposite to the first surface, the first surface is a light-facing surface, also called a front surface; the second surface is a backlight surface, also called a back surface.

[0044] like Figures 1 to 4 As shown, a front doping layer is provided on one side of the first surface of the substrate 1, and the front doping layer includes a first doping layer 2, and the doping type of the first doping layer 2 is the same as or opposite to the doping type of the substrate 1, for example, the doping type of the substrate 1 is N-type, and the doping type of the first doping layer 2 is P-type. When the doping type of the first doping layer 2 is opposite to that of the substrate 1, a PN junction can be formed between the first doping layer 2 and the substrate 1. The material of the first doping layer 2 can be amorphous silicon, microcrystalline silicon, polycrystalline silicon, single crystal silicon or a semiconductor compound (such as molybdenum dioxide, etc.).

[0045] A front electrode is disposed on the front side of the substrate 1 . The front electrode includes a first electrode 91 . The first electrode 91 is electrically connected to the first doping layer 2 .

[0046] In some examples, such as Figure 1 As shown, a third passivation layer 203 and a first anti-reflection layer 41 are sequentially arranged on the side of the first doped layer 2 away from the substrate 1, and the first electrode 91 passes through the third passivation layer 203 and the first anti-reflection layer 41. The third passivation layer 203 is mainly used to passivate the first doped layer 2. The first anti-reflection layer 41 is mainly used to reduce the reflectivity of the light directed to the solar cell, so that more sunlight can enter the solar cell, thereby improving the photoelectric conversion efficiency. For example, the material of the third passivation layer 203 is aluminum oxide, the material of the first anti-reflection layer 41 is silicon nitride (SiNx), and the material of the first doped layer 2 is one of doped amorphous silicon, microcrystalline silicon, polycrystalline silicon, single crystal silicon or compound semiconductor.

[0047] In this example, the first doping layer 2 is provided as a whole layer, which improves the ohmic contact effect with the substrate 1 to reduce the internal resistance, and can form a PN junction with a larger area, thereby improving the photoelectric conversion efficiency.

[0048] In other examples, such as Figure 3As shown, a first intrinsic passivation layer 51 is provided between the first doping layer 2 and the substrate 1, and a first transparent conductive layer 61 is provided on the side of the first doping layer 2 away from the substrate 1. The first intrinsic passivation layer 51 can improve the passivation efficiency of the solar cell and improve the open circuit voltage. The first transparent conductive layer 61 forms an ohmic contact with the first doping layer 2 to collect electricity and reduce the internal resistance of the solar cell. For example, the material of the first intrinsic passivation layer 51 is amorphous silicon, the material of the first transparent conductive layer 61 is one of ITO (Indium tin oxide), ICO (Indium oxide doped with cadmium), IWO (Indium oxide doped with tungsten), SnO2, etc., and the material of the first doping layer 2 is one of doped amorphous silicon, microcrystalline silicon, polycrystalline silicon, single crystal silicon or compound semiconductor.

[0049] When the material of the first doping layer 2 is microcrystalline silicon or polycrystalline silicon, light energy will be absorbed in the first doping layer 2 to generate parasitic absorption, thereby reducing the photoelectric conversion efficiency. Figure 4 As shown, the first doped layer 2 is intermittently arranged along the first direction to reduce the light receiving area of ​​the first doped layer 2, thereby reducing parasitic absorption and improving the photoelectric conversion efficiency. As a preferred solution, the orthographic projection of the first electrode 91 on the substrate 1 is within the range of the orthographic projection of the first doped layer 2 on the substrate 1 to reduce the light receiving area of ​​the first doped layer 2 as much as possible and minimize parasitic absorption. Of course, in other possible implementations, the first doped layer 2 can also be arranged as a whole layer.

[0050] Figure 1 and Figure 2 The front structure of the solar cell shown is the front structure of the TOPcon cell provided by the present disclosure. Figure 3 and Figure 4 The front structure of the solar cell shown is the front structure of the heterojunction cell provided in the present invention. The above is only described as an example to facilitate understanding of the scheme of the present invention, and is not a specific limitation of the present invention. In other possible embodiments, the front structure of the solar cell of the present invention may adopt the front structure of any known TOPcon cell, heterojunction cell, PERC cell or perovskite cell.

[0051] like Figures 1 to 4As shown, a back doping layer is provided on one side of the second surface of the substrate 1, and the back doping layer includes a third doping layer 7 and a fourth doping layer 8 insulated from each other and juxtaposed in a first direction (specifically, in the lateral direction in the figure), and the third doping layer 7 and the fourth doping layer 8 are alternately arranged in the first direction. The doping types of the third doping layer 7 and the fourth doping layer 8 are opposite, and the doping types of the first doping layer 2 and the third doping layer 7 are the same. For example, the doping type of the third doping layer 7 is P type, and the doping type of the fourth doping layer 8 is N type. One of the third doping layer 7 and the fourth doping layer 8 is opposite to the doping type of the substrate 1, so that a PN junction is formed between the third doping layer 7 and the substrate 1 or between the fourth doping layer 8 and the substrate 1.

[0052] The material of the third doping layer 7 and the fourth doping layer 8 can be one of amorphous silicon, microcrystalline silicon, polycrystalline silicon, single crystal silicon or semiconductor compounds (such as molybdenum dioxide, etc.). The third doping layer 7 and the fourth doping layer 8 can be formed by doping on the same intrinsic semiconductor layer, that is, they are arranged in the same layer. Of course, the third doping layer 7 and the fourth doping layer 8 can also be formed on different film layers, for example, by patterning processes on different deposited film layers.

[0053] The substrate 1 is further provided with a third electrode 93 and a fourth electrode 94 on one side of the second surface. The third electrode 93 is electrically connected to the third doping layer 7 , and the fourth electrode 94 is electrically connected to the fourth doping layer 8 .

[0054] In some examples, a second tunneling oxide layer 102 is disposed between at least one of the third doping layer 7 and the fourth doping layer 8 and the substrate 1 , and a second anti-reflection layer 42 is disposed on a side away from the substrate 1 .

[0055] For example, Figure 1 As shown, a second tunnel oxide layer 102 is provided between the third doped layer 7 and the substrate 1 and between the fourth doped layer 8 and the substrate 1, and the second tunnel oxide layer 102 is provided on the entire surface. The second tunnel oxide layer 102 can saturate the dangling bonds on the surface of the substrate 1, reduce the interface defect state density on the second surface of the substrate 1, thereby reducing the recombination center on the second surface of the substrate 1, thereby reducing the recombination rate of carriers, and ultimately increasing the open circuit voltage of the solar cell, and improving the photoelectric conversion efficiency of the solar cell.

[0056] A second anti-reflection layer 42 is disposed on the side of the third doped layer 7 and the fourth doped layer 8 away from the substrate 1. The second anti-reflection layer 42 can reduce the reflectivity of the back incident light entering the cell, thereby allowing more back light to enter the solar cell to improve the light absorption efficiency.

[0057] For example, the material of the second tunnel oxide layer 102 may be any one of silicon oxide, aluminum oxide, tantalum oxide, zirconium oxide, and titanium dioxide, and the material of the second anti-reflection layer 42 may be silicon nitride (SiNx).

[0058] In addition, if Figure 2 As shown, when the materials of the third doping layer 7 and the fourth doping layer 8 are microcrystalline silicon or polycrystalline silicon, the orthographic projection of the third electrode 93 on the substrate 1 is within the orthographic projection range of the third doping layer 7 on the substrate 1, and the orthographic projection of the fourth electrode 94 on the substrate 1 is within the orthographic projection range of the fourth doping layer 8 on the substrate 1, so as to minimize the light receiving area of ​​the third doping layer 7 and the fourth doping layer 8, thereby reducing the parasitic absorption of the third doping layer 7 and the fourth doping layer 8.

[0059] In some other examples, a second intrinsic passivation layer 52 is disposed between at least one of the third doping layer 7 and the fourth doping layer 8 and the substrate, and a transparent conductive layer is disposed on the side away from the substrate 1 .

[0060] For example, Figure 3 As shown, a second intrinsic passivation layer 52 is provided between the third doping layer 7 and the substrate 1 and between the fourth doping layer 8 and the substrate 1, a third transparent conductive layer 63 is provided on the side of the third doping layer 7 away from the substrate 1, and a fourth transparent conductive layer 64 is provided on the side of the fourth doping layer 8 away from the substrate 1. The third transparent conductive layer 63 and the fourth transparent conductive layer 64 are insulated from each other, specifically, an isolation groove is provided between the third transparent conductive layer 63 and the fourth transparent conductive layer 64 to achieve electrical insulation. The third transparent conductive layer 63 is electrically connected to the third electrode 93, and the fourth transparent conductive layer 64 is electrically connected to the fourth electrode 94.

[0061] The second intrinsic passivation layer 52 can improve the passivation efficiency of the solar cell and increase the open circuit voltage. The third transparent conductive layer 63 forms an ohmic contact with the third doped layer 7 to collect electricity, and the fourth transparent conductive layer 64 forms an ohmic contact with the fourth doped layer 8 to collect electricity, which is used to reduce the internal resistance of the battery. For example, the material of the second intrinsic passivation layer 52 is amorphous silicon, and the material of the third transparent conductive layer 63 and the fourth transparent conductive layer 64 is one of ITO (Indium tin oxide), ICO (Indium oxide doped with cadmium), IWO (Indium oxide doped with tungsten), SnO2, etc.

[0062] In addition, if Figure 4 As shown, when the materials of the third doping layer 7 and the fourth doping layer 8 are microcrystalline silicon or polycrystalline silicon, the orthographic projection of the third electrode 93 on the substrate 1 is within the orthographic projection range of the third doping layer 7 on the substrate 1, and the orthographic projection of the fourth electrode 94 on the substrate 1 is within the orthographic projection range of the fourth doping layer 8 on the substrate 1, so as to minimize the light receiving area of ​​the third doping layer 7 and the fourth doping layer 8, thereby reducing the parasitic absorption of the third doping layer 7 and the fourth doping layer 8.

[0063] In some other examples, a second passivation layer 202 is disposed on one side of the second surface of the substrate 1 , and at least one of the third electrode 93 and the fourth electrode 94 is electrically connected through a doping layer corresponding to the second passivation layer 202 .

[0064] like Figure 5 As shown, a second passivation layer 202 is disposed on the second surface of the substrate 1 , a groove is opened on one side of the second surface of the substrate 1 , a third doping layer 7 is disposed at the bottom of the groove, and the third electrode 93 passes through the second passivation layer 202 and is electrically connected to the third doping layer 7 .

[0065] Figure 1 and Figure 2 The back structure of the solar cell shown is the back structure of the TBC (TOPCon combined with Back Contact technology) cell provided by the present disclosure. Figure 3 and Figure 4 The back structure of the solar cell shown is the back structure of the HBC (HJT combined with Back Contact technology) cell provided by the present disclosure. Figure 5 The third electrode and the third doping layer corresponding structure in the back structure of the solar cell shown is a PERC cell back structure. The above is only explained as an example to facilitate understanding of the scheme of the present disclosure, and is not a specific limitation of the present disclosure. In other possible embodiments, the back structure of the solar cell of the present disclosure may adopt the back structure of any known XBC (a cell combined with Back Contact technology, such as TBC, HBC, etc.), or any one of the third electrode and the third doping layer corresponding structure and the fourth electrode and the fourth doping layer corresponding structure may be the same as one of the PERC cell back structure, the TOPCon cell back structure and the HJT cell back structure.

[0066] The solar cell provided by the present disclosure has two carrier transmission paths, namely, between the first electrode 91 and the fourth electrode 94 and between the third electrode 93 and the fourth electrode 94. The internal resistance of the solar cell is the resistance value of the transmission resistances of the two carrier transmission paths connected in parallel. Therefore, the internal resistance of the solar cell can be reduced, thereby improving the conversion efficiency of the solar cell. In addition, if the doping types of the first doping layer 2 and the substrate 1 are opposite, PN junctions can be formed between the first doping layer 2 and the substrate 1 and between the third doping layer 7 and the substrate 1, the photoelectric conversion efficiency is increased, and the conversion efficiency of the solar cell is also improved accordingly.

[0067] The present disclosure also provides a method for preparing a solar cell, which comprises: providing a substrate, the substrate comprising a first surface and a second surface opposite to the first surface; forming a front doping layer on one side of the first surface of the substrate; forming a back doping layer on one side of the second surface of the substrate, the back doping layer comprising a third doping layer and a fourth doping layer juxtaposed along a first direction and insulated from each other, wherein the doping types of the third doping layer and the fourth doping layer are opposite; forming a front electrode and a back electrode, the front electrode being electrically connected to the front doping layer, and the back electrode being electrically connected to the back doping layer.

[0068] In some embodiments, the preparation Figure 1 or Figure 2 Taking the solar cell shown as an example, the method for preparing the solar cell provided by the embodiment of the present disclosure is introduced.

[0069] First, a substrate 1 is provided. The material of the substrate 1 is silicon, and the substrate 1 can be an N-type doped silicon substrate, or a P-type doped silicon substrate. The substrate 1 includes a first surface and a second surface opposite to the first surface, the first surface is a light-facing surface, also called a front surface; the second surface is a backlight surface, also called a back surface.

[0070] The first surface and the second surface of the substrate 1 are textured, or the first surface of the substrate 1 is textured and the second surface of the substrate 1 is polished. After the first surface of the substrate 1 is textured, the film layers formed on the first surface have the same texture structure as the first surface.

[0071] like Figure 1 As shown, a first doping layer 2 is formed on the first surface of the substrate 1. For example, the first surface of the substrate 1 is doped to form the first doping layer 2 on the first surface. For another example, the first doping layer 2 is formed on one side of the first surface of the substrate 1 by chemical vapor deposition. The first doping layer 2 is arranged on the entire surface, and the doping type of the first doping layer 2 can be the same as or opposite to the doping type of the substrate 1. Among them, if the doping type of the first doping layer 2 is opposite to the doping type of the substrate 1, a PN junction can be formed on the front side of the battery.

[0072] A third passivation layer 203 and a first anti-reflection layer 41 are sequentially formed on the first doped layer 2. The third passivation layer 203 is mainly used to passivate the first doped layer 2. The first anti-reflection layer 41 is mainly used to reduce the reflectivity of light directed to the solar cell, so that more sunlight can enter the solar cell, thereby improving the photoelectric conversion efficiency. For example, the material of the third passivation layer 203 is aluminum oxide, and the material of the first anti-reflection layer 41 is silicon nitride (SiNx).

[0073] A second tunnel oxide layer 102 is formed on the second surface of the substrate 1. The material of the second tunnel oxide layer 102 can be any one of silicon oxide, aluminum oxide, tantalum oxide, zirconium oxide, and titanium dioxide. For example, the second tunnel oxide layer 102 is formed by LPCVD (Low Pressure Chemical Vapor Deposition).

[0074] A third doping layer 7 and a fourth doping layer 8 are formed, and the third doping layer 7 and the fourth doping layer 8 are alternately arranged along the first direction.

[0075] For example, an intrinsic polysilicon layer is first formed, and then doping is performed on the intrinsic polysilicon layer to form the third doping layer 7 and the fourth doping layer 8. The intrinsic polysilicon layer between the third doping layer 7 and the fourth doping layer 8 is used to insulate the third doping layer 7 and the fourth doping layer 8, or the intrinsic polysilicon layer is etched to remove the intrinsic polysilicon layer between the third doping layer 7 and the fourth doping layer 8, and an isolation groove is formed to insulate the third doping layer 7 and the fourth doping layer 8.

[0076] For another example, a second doping material layer is first formed by chemical vapor deposition, and the second doping material layer is etched (for example, laser etching, dry etching, or wet etching) to form a third doping layer 7; then, a third doping material layer is formed by chemical vapor deposition, and the third doping material layer is etched (for example, laser etching, dry etching, or wet etching) to form a fourth doping layer 8.

[0077] A second anti-reflection layer 42 is formed on a side of the third doping layer 7 and the fourth doping layer 8 away from the substrate 1 .

[0078] A first electrode 91, a third electrode 93 and a fourth electrode 94 are formed, wherein the first electrode 91 forms an ohmic contact with the first doping layer 2 for electrical connection, the third electrode 93 forms an ohmic contact with the third doping layer 7 for electrical connection, and the fourth electrode 94 forms an ohmic contact with the fourth doping layer 8 for electrical connection. The materials of the first electrode 91, the third electrode 93 and the fourth electrode 94 may be silver, copper, alloys or pastes thereof.

[0079] For example, metal paste is printed on the first anti-reflection layer 41 , and then the metal paste is sintered, so that the metal paste corrodes the first anti-reflection layer 41 and the third passivation layer 203 to form an ohmic contact with the first doping layer 2 .

[0080] For example, metal paste is printed on the second anti-reflection layer 42, and the metal paste is sintered so that the metal paste corrodes the second anti-reflection layer 42 and then forms ohmic contact with the third doping layer 7 and the fourth doping layer 8. The metal paste that forms ohmic contact with the third doping layer 7 is cooled to form the third electrode 93, and the metal paste that forms ohmic contact with the fourth doping layer 8 is cooled to form the fourth electrode 94.

[0081] Some possible examples include Figure 2 As shown, the orthographic projection of the third doped layer 7 on the substrate 1 is in the same range as the orthographic projection of the third electrode 93 on the substrate 1, and the orthographic projection of the fourth doped layer 8 on the substrate 1 is in the same range as the orthographic projection of the fourth electrode 94 on the substrate 1, so as to minimize the light receiving area of ​​the third doped layer 7 and the fourth doped layer 8, thereby reducing the parasitic absorption of the third doped layer 7 and the fourth doped layer 8.

[0082] In other embodiments, the Figure 3 or Figure 4 Taking the solar cell shown as an example, the method for preparing the solar cell provided by the embodiment of the present disclosure is introduced.

[0083] First, a substrate 1 is provided. The material of the substrate 1 is silicon, and the substrate 1 can be an N-type doped silicon substrate, or a P-type doped silicon substrate. The substrate 1 includes a first surface and a second surface opposite to the first surface, the first surface is a light-facing surface, also called a front surface; the second surface is a backlight surface, also called a back surface.

[0084] The first surface and the second surface of the substrate 1 are textured, or the first surface of the substrate 1 is textured and the second surface of the substrate 1 is polished. After the first surface of the substrate 1 is textured, the film layers formed on the first surface have the same texture structure as the first surface.

[0085] like Figure 3 As shown, a first intrinsic passivation layer 51 and a first doping layer 2 are sequentially formed on the first surface of the substrate 1. For example, the first intrinsic passivation layer 51 is amorphous silicon, and the first doping layer 2 is nanocrystalline silicon, microcrystalline silicon or amorphous silicon. For example, the first intrinsic passivation layer 51 and the first doping layer 2 are formed by PECVD.

[0086] A first transparent conductive layer 61 is formed on the first doping layer 2, and the first transparent conductive layer 61 forms an ohmic contact with the first doping layer 2. A first electrode 91 is formed, and the first electrode 91 forms an ohmic contact with the first doping layer 2.

[0087] Some possible examples include Figure 4As shown, before forming the first transparent conductive layer 61, the first doped layer 2 is etched (such as laser etching, dry etching or wet etching) to reduce the light receiving area of ​​the first doped layer 2 and reduce the parasitic absorption generated by the first doped layer 2. At this time, the first transparent conductive layer 61 can be electrically connected to all the etched first doped layers 2 to collect electricity, thereby reducing the internal resistance of the solar cell. For example, the orthographic projection of the first doped layer 2 on the substrate 1 is the same as the orthographic projection range of the first electrode 91 on the substrate 1, so as to reduce the light receiving area of ​​the first doped layer 2 as much as possible and minimize the parasitic absorption.

[0088] like Figure 3 As shown, a second intrinsic passivation layer 52 is formed on the second surface of the substrate 1 .

[0089] A third doping layer 7 and a fourth doping layer 8 are formed on the second intrinsic passivation layer 52. For example, a second doping material layer is first formed, and then the second doping material layer is etched (such as laser etching, dry etching, or wet etching) to form the third doping layer 7; then a third doping material layer is formed, and then the third doping material layer is etched to form the fourth doping layer 8.

[0090] A third transparent conductive layer 63 and a fourth transparent conductive layer 64 are formed which are electrically insulated from each other, wherein the third transparent conductive layer 63 forms an ohmic contact with the third doping layer 7, and the fourth transparent conductive layer 64 forms an ohmic contact with the fourth doping layer 8. For example, a material layer of a transparent conductive layer is first formed, and then the material layer of the transparent conductive layer is etched to form the third transparent conductive layer 63 and the fourth transparent conductive layer 64.

[0091] A third electrode 93 and a fourth electrode 94 are formed. The third electrode 93 is electrically connected to the third transparent conductive layer 63 , and the fourth electrode 94 is electrically connected to the fourth transparent conductive layer 64 .

[0092] In some possible examples, the orthographic projection of the third doping layer 7 on the substrate 1 is in the same range as the orthographic projection of the third electrode 93 on the substrate 1, and the orthographic projection of the fourth doping layer 8 on the substrate 1 is in the same range as the orthographic projection of the fourth electrode 94 on the substrate 1, so as to minimize the light receiving area of ​​the third doping layer 7 and the fourth doping layer 8, thereby reducing the parasitic absorption of the third doping layer 7 and the fourth doping layer 8.

[0093] Embodiment 2

[0094] The embodiment of the present disclosure provides a solar cell, whose substrate and back structure are the same as the substrate and back structure of the solar cell provided in the first embodiment, except that the front structure of the solar cell is different.

[0095] like Figure 6As shown, a front doping layer is provided on one side of the first surface of the substrate 1, and the front doping layer includes a first doping layer 2 and a second doping layer 3 juxtaposed along a first direction and insulated from each other, the first doping layer 2 and the second doping layer 3 are alternately arranged in the first direction, and the doping types of the first doping layer 2 and the second doping layer 3 are opposite. For example, the doping type of the first doping layer 2 is P type, and the doping type of the second doping layer 3 is N type, and a PN junction can be formed between one of the first doping layer 2 and the second doping layer 3 and the substrate 1. The materials of the first doping layer 2 and the second doping layer 3 can be amorphous silicon, microcrystalline silicon, polycrystalline silicon, single crystal silicon or semiconductor compounds (such as molybdenum dioxide, etc.).

[0096] The first doping layer 2 and the second doping layer 3 can be formed by doping on the same intrinsic semiconductor layer (such as an intrinsic polysilicon layer), that is, they are arranged in the same layer. Of course, the first doping layer 2 and the second doping layer 3 can also be formed on different film layers, for example, forming a first doping layer material layer-doping-etching the first doping material layer to form the first doping layer 2, forming a second doping material layer-doping-etching the second doping material layer to form the second doping layer 3.

[0097] A first electrode 91 and a second electrode 92 are disposed on the front surface of the substrate 1 . The first electrode 91 is electrically connected to the first doping layer 2 , and the second electrode 92 is electrically connected to the second doping layer 3 .

[0098] In some examples, a first tunneling oxide layer 101 is disposed between at least one of the first doping layer 2 and the second doping layer 3 and the substrate 1 , and a first anti-reflection layer 41 is disposed on a side away from the substrate 1 .

[0099] For example, Figure 6 As shown, a first tunneling oxide layer 101 is provided between the first doping layer 2 and the substrate 1 and between the second doping layer 3 and the substrate 1, and the first tunneling oxide layer 101 is provided on the entire surface. The first tunneling oxide layer 101 can saturate the dangling bonds on the surface of the substrate 1, reduce the cross-sectional defect state density on the first surface of the substrate 1, and ultimately reduce the recombination center on the second surface of the substrate 1, thereby reducing the recombination rate of carriers, and ultimately increasing the open circuit voltage of the solar cell, thereby improving the photoelectric conversion efficiency of the solar cell.

[0100] A first anti-reflection layer 41 is disposed on the side of the first doped layer 2 and the second doped layer 3 away from the substrate 1. The first anti-reflection layer 41 is mainly used to reduce the reflectivity of light directed to the solar cell, allowing more sunlight to enter the solar cell, thereby improving the photoelectric conversion efficiency.

[0101] For example, the material of the first tunnel oxide layer 101 may be any one of silicon oxide, aluminum oxide, tantalum oxide, zirconium oxide, and titanium dioxide, and the material of the first anti-reflection layer 41 may be silicon nitride (SiNx).

[0102] In addition, if Figure 7 As shown, when the materials of the first doping layer 2 and the second doping layer 3 are microcrystalline silicon or polycrystalline silicon, the orthographic projection range of the first electrode 91 on the substrate 1 is within the orthographic projection range of the first doping layer 2 on the substrate 1, and the orthographic projection range of the second electrode 92 on the substrate 1 is within the orthographic projection range of the second doping layer 3 on the substrate 1, so as to minimize the light receiving area of ​​the first doping layer 2 and the second doping layer 3, thereby reducing the parasitic absorption of the first doping layer 2 and the second doping layer 3.

[0103] In some other examples, a first intrinsic passivation layer 51 is disposed between at least one of the first doping layer 2 and the second doping layer 3 and the substrate 1 , and a transparent conductive layer is disposed on the side away from the substrate 1 .

[0104] For example, Figure 8 As shown, a first intrinsic passivation layer 51 is disposed between the first doping layer 2 and the substrate 1 and between the second doping layer 3 and the substrate 1, a first transparent conductive layer 61 is disposed on the side of the first doping layer 2 away from the substrate 1, and a second transparent conductive layer 62 is disposed on the side of the second doping layer 3 away from the substrate 1. The first transparent conductive layer 61 and the second transparent conductive layer 62 are insulated from each other, specifically, an isolation groove is disposed between the first transparent conductive layer 61 and the second transparent conductive layer 62 to achieve electrical insulation. The first transparent conductive layer 61 is electrically connected to the first electrode 91, and the second transparent conductive layer 62 is electrically connected to the second electrode 92.

[0105] Among them, the first intrinsic passivation layer 51 can improve the passivation efficiency of the solar cell and improve the open circuit voltage. The first transparent conductive layer 61 forms an ohmic contact with the first doped layer 2 to collect electricity, and the second transparent conductive layer 62 forms an ohmic contact with the second doped layer 3 to collect electricity, which is used to reduce the internal resistance of the battery. For example, the material of the first intrinsic passivation layer 51 is amorphous silicon, and the material of the first transparent conductive layer 61 and the second transparent conductive layer 62 is one of ITO (Indium tin oxide), ICO (Indium oxide doped with cadmium), IWO (Indium oxide doped with tungsten), SnO2, etc.

[0106] In addition, if Fig. 9 As shown, when the first doped layer 2 and the second doped layer 3 are microcrystalline silicon or polycrystalline silicon, the orthographic projection of the first electrode 91 on the substrate 1 is within the orthographic projection range of the first doped layer 2 on the substrate 1, and the orthographic projection of the second electrode 92 on the substrate 1 is within the orthographic projection range of the second doped layer 3 on the substrate 1, so as to minimize the light receiving area of ​​the first doped layer 2 and the second doped layer 3, thereby reducing the parasitic absorption of the first doped layer 2 and the second doped layer 3.

[0107] In some other examples, a first passivation layer 201 is disposed on one side of the first surface of the substrate 1 , and at least one of the first electrode 91 and the second electrode 92 penetrates the first passivation layer 201 and is electrically connected to the corresponding doping layer.

[0108] like Fig.10 As shown, a first passivation layer 201 is disposed on the first surface of the substrate 1 , a groove is opened on one side of the first surface of the substrate 1 , a second doping layer 3 is disposed at the bottom of the groove, and the second electrode 92 passes through the first passivation layer 201 and is electrically connected to the second doping layer 3 .

[0109] Figure 6 and Figure 7 The front structure of the solar cell shown is the same as the back structure of a TBC (TOPCon combined with Back Contact technology) cell. Figure 8 and Fig. 9 The front structure of the solar cell shown is the same as the back structure of an HBC (HJT combined with BackContact technology) cell. Fig.10 The structures corresponding to the second electrode 92 and the second doping layer 3 of the solar cell are the same as the back structure of the PERC cell. The above is only an example to facilitate understanding of the scheme of the present disclosure, and is not a specific limitation of the present disclosure. In other possible embodiments, the front structure of the solar cell of the present disclosure may be the same as the back structure of any known XBC (a cell combined with Back Contact technology, such as TBC, HBC, etc.), or any one of the structures corresponding to the first electrode 91 and the first doping layer 2 and the structures corresponding to the second electrode 92 and the second doping layer 3 may be the same as one of the back structures of the PERC cell, the back structure of the TOPCon cell, and the back structure of the HJT cell.

[0110] The solar cell provided by the embodiment of the present disclosure has four carrier transmission paths, namely, between the first electrode 91 and the second electrode 92, between the first electrode 91 and the fourth electrode 94, between the second electrode 92 and the third electrode 93, and between the third electrode 93 and the fourth electrode 94. Therefore, the internal resistance of the solar cell can be reduced, thereby improving the conversion efficiency of the solar cell. In addition, a PN junction can be formed between one of the first doping layer 2 and the second doping layer 3 and the substrate 1, and a PN junction can be formed between one of the third doping layer 7 and the fourth doping layer 8 and the substrate 1, the photoelectric conversion efficiency is increased, and the conversion efficiency of the solar cell is also improved accordingly.

[0111] In some examples, the Figure 6 or Figure 7 As an example of the solar cell shown in FIG. 1 , the method for preparing the solar cell provided in the embodiment of the present disclosure is similar to the method for preparing the solar cell provided in the embodiment 1. Figure 1 or Figure 2The difference between the manufacturing methods of the solar cells shown is that the methods for manufacturing the front structure are different. The details are as follows:

[0112] like Figure 6 As shown, a first tunnel oxide layer 101 is formed on the first surface of the substrate 1. The material of the first tunnel oxide layer 101 can be any one of silicon oxide, aluminum oxide, tantalum oxide, zirconium oxide, and titanium dioxide. For example, the first tunnel oxide layer 101 is formed by LPCVD (Low Pressure Chemical Vapor Deposition).

[0113] A first doping layer 2 and a second doping layer 3 are formed on the first tunneling oxide layer 101 , and the first doping layer 2 and the second doping layer 3 are alternately arranged along a first direction.

[0114] For example, a first intrinsic polysilicon layer is first formed, and then doping is performed on the first intrinsic polysilicon layer to form a first doping layer 2 and a second doping layer 3. The first intrinsic polysilicon layer between the first doping layer 2 and the second doping layer 3 is used to insulate the first doping layer 2 and the second doping layer 3, or the first intrinsic polysilicon layer is etched to remove the first intrinsic polysilicon layer between the first doping layer 2 and the second doping layer 3, and an isolation groove is formed to insulate the first doping layer 2 and the second doping layer 3.

[0115] For another example, a first doping material layer is first formed by chemical vapor deposition, and the first doping material layer is etched (for example, laser etching, dry etching, or wet etching) to form a first doping layer 2; then, a second doping material layer is formed by chemical vapor deposition, and the second doping material layer is etched (for example, laser etching, dry etching, or wet etching) to form a second doping layer 3.

[0116] A first anti-reflection layer 41 is formed on the side of the first doping layer 2 and the second doping layer 3 away from the substrate 1. The first anti-reflection layer 41 is mainly used to reduce the reflectivity of light directed to the solar cell, so that more sunlight can enter the solar cell, thereby improving the photoelectric conversion efficiency. For example, the material of the first anti-reflection layer 41 is silicon nitride (SiNx).

[0117] Some possible examples include Figure 7 As shown, the orthographic projection of the first doped layer 2 on the substrate 1 is in the same range as the orthographic projection of the first electrode 91 on the substrate 1, and the orthographic projection of the second doped layer 3 on the substrate 1 is in the same range as the orthographic projection of the second electrode 92 on the substrate 1, so as to minimize the light receiving area of ​​the first doped layer 2 and the second doped layer 3, thereby reducing the parasitic absorption of the first doped layer 2 and the second doped layer 3.

[0118] In other examples, the Figure 8 or Fig. 9 As an example of the solar cell shown in FIG. 1 , the method for preparing the solar cell provided in the embodiment of the present disclosure is similar to the method for preparing the solar cell provided in the embodiment 1. Figure 3 or Figure 4 The difference between the manufacturing methods of the solar cells shown is that the methods for manufacturing the front structure are different. The details are as follows:

[0119] like Figure 8 As shown, a first intrinsic passivation layer 51 is formed on the first surface of the substrate 1. For example, the first intrinsic passivation layer 51 is amorphous silicon and is formed by PECVD.

[0120] A first doping layer 2 and a second doping layer 3 are formed on the first intrinsic passivation layer 51. For example, a first doping material layer is first formed on the first intrinsic passivation layer 51, and the first doping material layer is etched (laser etching, dry etching, or wet etching) to form the first doping layer 2; then a second doping material layer is formed, and the second doping material layer is etched to form the second doping layer 3. For example, the first doping material layer and the second doping material layer are formed by PECVD.

[0121] For example, the first doping layer 2 and the second doping layer 3 are nanocrystalline silicon, microcrystalline silicon or amorphous silicon.

[0122] A first transparent conductive layer 61 and a second transparent conductive layer 62 are formed which are electrically insulated from each other, wherein the first transparent conductive layer 61 forms an ohmic contact with the first doped layer 2, and the second transparent conductive layer 62 forms an ohmic contact with the second doped layer 3. For example, a material layer of a transparent conductive layer is first formed on the entire surface of the first doped layer 2 and the second doped layer 3 away from the substrate 1, and then the material layer of the transparent conductive layer is etched to form the first transparent conductive layer 61 and the second transparent conductive layer 62.

[0123] A first electrode 91 and a second electrode 92 are formed. The first electrode 91 is electrically connected to the first transparent conductive layer 61 , and the second electrode 92 is electrically connected to the second transparent conductive layer 62 .

[0124] Some possible examples include Fig. 9 As shown, the orthographic projection of the first doped layer 2 on the substrate 1 is in the same range as the orthographic projection of the first electrode 91 on the substrate 1, and the orthographic projection of the second doped layer 3 on the substrate 1 is in the same range as the orthographic projection of the second electrode 92 on the substrate 1, so as to minimize the light receiving area of ​​the first doped layer 2 and the second doped layer 3, thereby reducing the parasitic absorption of the first doped layer 2 and the second doped layer 3.

[0125] The present disclosure further provides a solar cell assembly, comprising a plurality of solar cells connected in series and / or in parallel, wherein the solar cell structure is as shown in the first or second embodiment.

[0126] There are a few points to note:

[0127] (1) The drawings of the embodiments of the present disclosure only relate to the structures related to the embodiments of the present disclosure. Other structures may refer to the general design;

[0128] (2) For the sake of clarity, in the drawings used to describe the embodiments of the present disclosure, the thickness of the layers or regions is exaggerated or reduced, that is, these drawings are not drawn according to the actual scale. It is understood that when an element such as a layer, film, region or substrate is referred to as being "on" or "under" another element, the element may be "directly" "on" or "under" the other element or there may be intermediate elements;

[0129] (3) In the absence of conflict, the embodiments of the present disclosure and the features therein may be combined with each other to obtain new embodiments.

[0130] The above is only a specific implementation of the present disclosure, but the protection scope of the present disclosure is not limited thereto. Any person skilled in the art who is familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present disclosure, which should be included in the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be based on the protection scope of the claims.

Claims

1. A solar cell, characterized in that: include: a substrate comprising a first surface and a second surface opposite to the first surface; A front doping layer, disposed on one side of the first surface of the substrate; a back doping layer, disposed on one side of the second surface of the substrate, comprising a third doping layer and a fourth doping layer juxtaposed along a first direction and insulated from each other, wherein the third doping layer and the fourth doping layer have opposite doping types; A front electrode electrically connected to the front doped layer; A back electrode is electrically connected to the back doped layer, and the back electrode includes a third electrode and a fourth electrode. The third electrode is electrically connected to the third doped layer, and the fourth electrode is electrically connected to the fourth doped layer.

2. The solar cell according to claim 1, characterized in that The front doping layer comprises a first doping layer, and a third passivation layer and a first anti-reflection layer are sequentially arranged on a side of the first doping layer away from the substrate.

3. The solar cell according to claim 1, characterized in that The front doping layer includes a first doping layer, a first intrinsic passivation layer is arranged between the first doping layer and the substrate, and a first transparent conductive layer is arranged on a side of the first doping layer away from the substrate.

4. The solar cell according to claim 3, characterized in that: The first doping layer is disposed on the entire surface; or, The orthographic projection of the front electrode on the substrate is located within the orthographic projection of the first doped layer on the substrate.

5. The solar cell according to claim 1, characterized in that: The front doping layer includes a first doping layer and a second doping layer which are juxtaposed along a first direction and insulated from each other, and the first doping layer and the second doping layer have opposite doping types.

6. The solar cell according to claim 5, characterized in that: The first doping layer and the second doping layer are arranged in the same layer.

7. The solar cell according to claim 5, characterized in that: A first tunneling oxide layer is arranged between at least one of the first doping layer and the second doping layer and the substrate, and a first anti-reflection layer is arranged on a side away from the substrate.

8. The solar cell according to claim 5, characterized in that: A first intrinsic passivation layer is disposed between at least one of the first doping layer and the second doping layer and the substrate, and a transparent conductive layer is disposed on a side away from the substrate.

9. The solar cell according to claim 5, characterized in that: The front electrode includes a first electrode and a second electrode, the first electrode is electrically connected to the first doping layer, and the second electrode is electrically connected to the second doping layer. A first passivation layer is arranged on one side of the first surface of the substrate, and at least one of the first electrode and the second electrode is electrically connected to the corresponding doping layer after penetrating the first passivation layer.

10. The solar cell according to claim 7 or 8, characterized in that: The front electrode includes a first electrode and a second electrode, the first electrode is electrically connected to the first doping layer, and the second electrode is electrically connected to the second doping layer. The orthographic projection of the first electrode on the substrate is within the range of the orthographic projection of the first doped layer on the substrate; and / or, The orthographic projection of the second electrode on the substrate is within the range of the orthographic projection of the second doped layer on the substrate.

11. The solar cell according to claim 1, characterized in that: The third doping layer and the fourth doping layer are arranged in the same layer.

12. The solar cell according to claim 1, characterized in that A second tunneling oxide layer is disposed between at least one of the third doping layer and the fourth doping layer and the substrate, and a second anti-reflection layer is disposed on a side away from the substrate.

13. The solar cell according to claim 1, characterized in that A second intrinsic passivation layer is disposed between at least one of the third doping layer and the fourth doping layer and the substrate, and a transparent conductive layer is disposed on a side away from the substrate.

14. The solar cell according to claim 1, characterized in that A second passivation layer is disposed on one side of the second surface of the substrate, and at least one of the third electrode and the fourth electrode penetrates the second passivation layer and is electrically connected to the corresponding doping layer.

15. The solar cell according to claim 12 or 13, characterized in that: The orthographic projection of the third electrode on the substrate is located within the orthographic projection range of the third doped layer on the substrate; and / or, The orthographic projection of the fourth electrode on the substrate is located within the orthographic projection range of the fourth doping layer on the substrate.

16. The solar cell according to claim 1, characterized in that The material of the front doping layer or the back doping layer is one of amorphous silicon, microcrystalline silicon, polycrystalline silicon, single crystal silicon or compound semiconductor.

17. A method for preparing a solar cell, characterized in that: include: providing a substrate, the substrate comprising a first surface and a second surface opposite to the first surface; forming a front doping layer on one side of the first surface of the substrate; forming a back doping layer on one side of the second surface of the substrate, the back doping layer comprising a third doping layer and a fourth doping layer juxtaposed along the first direction and insulated from each other, wherein the third doping layer and the fourth doping layer have opposite doping types; A front electrode and a back electrode are formed, wherein the front electrode is electrically connected to the front doped layer, and the back electrode is electrically connected to the back doped layer.

18. A solar cell module, characterized in that: comprising a plurality of solar cells connected in series and / or in parallel; The solar cell comprises: a substrate comprising a first surface and a second surface opposite to the first surface; A front doping layer, disposed on one side of the first surface of the substrate; a back doping layer, disposed on one side of the second surface of the substrate, comprising a third doping layer and a fourth doping layer juxtaposed along a first direction and insulated from each other, wherein the third doping layer and the fourth doping layer have opposite doping types; A front electrode electrically connected to the front doped layer; A back electrode is electrically connected to the back doped layer, and the back electrode includes a third electrode and a fourth electrode. The third electrode is electrically connected to the third doped layer, and the fourth electrode is electrically connected to the fourth doped layer.

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