Solar cell and photovoltaic module

Abstract

The embodiment of the present application relates to the photovoltaic field, and provides a solar cell and a photovoltaic module, the solar cell comprises: a substrate; a doped layer, the doping concentration of the doped layer is greater than the doping concentration of the substrate, the doped layer comprises a plurality of first doped regions arranged at intervals along a first direction, a second doped region located between adjacent first doped regions and a third doped region, the doping concentration of the first doped region is less than the doping concentration of the second doped region and less than the doping concentration of the third doped region; a tunneling dielectric layer, the tunneling dielectric layer is located on the surface of the first doped region and the surface of the second doped region; a doped conductive layer, the doped conductive layer is opposite to the first doped region; a first electrode, each first electrode is arranged on the side of the doped conductive layer away from the substrate and is electrically connected with the doped conductive layer; a plurality of conductive transport layers, the conductive transport layers are opposite to the second doped regions, and the conductive transport layers are located on the surface of the tunneling dielectric layer.The embodiment of the present application is favorable to improve the photoelectric conversion efficiency of the solar cell.

Description

Technical Field

[0001] This application relates to the photovoltaic field, and in particular to a solar cell and a photovoltaic module. Background Technology

[0002] Factors affecting the performance of solar cells (such as photoelectric conversion efficiency) include optical losses and electrical losses. Optical losses include reflection losses from the front surface of the cell, shading losses from the contact grid lines, and non-absorption losses in the long wavelength range. Electrical losses include photogenerated carrier recombination on the semiconductor surface and within the cell, contact resistance between the semiconductor and metal grid lines, and contact resistance between the metal and semiconductor.

[0003] To reduce electrical and optical losses in solar cells, a polishing process is generally required on the back side of the cell. Back-side polishing primarily utilizes wet chemical methods to polish the boron-doped pyramidal textured surface structure on the back side, increasing internal light reflection, reducing the carrier surface recombination rate, and improving the cell's photoelectric conversion efficiency. In the back-side polishing process, the morphology of the polished back surface of crystalline silicon cells is beneficial for back reflection of long-wavelength light and the uniformity of subsequent film formation on the back side, playing a crucial role in improving solar cell efficiency. While back-side polishing can optimize solar cell performance, many factors still influence the performance of this type of solar cell, making the development of high-efficiency passivated contact solar cells of significant importance. Summary of the Invention

[0004] This application provides a solar cell and a photovoltaic module, which at least helps to improve the photoelectric conversion efficiency of the solar cell.

[0005] According to some embodiments of this application, one aspect of this application provides a solar cell, comprising: a substrate; a doped layer located within a first surface adjacent to the substrate, wherein the doped element type in the doped layer is the same as that in the substrate, the doping concentration of the doped layer is greater than that of the substrate, the doped layer includes a plurality of first doped regions spaced apart along a first direction, a second doped region located between adjacent first doped regions, and a third doped region, wherein the doping concentration of the first doped region is less than that of the second doped region and less than that of the third doped region; a tunneling dielectric layer located on the surfaces of the first doped regions and the second doped regions; a plurality of doped conductive layers spaced apart along the first direction, the doped conductive layers facing the first doped regions and located on the surface of the tunneling dielectric layer; a plurality of first electrodes spaced apart along the first direction, the first electrodes extending along a second direction, each first electrode being disposed on the side of the doped conductive layer away from the substrate and electrically connected to the doped conductive layer; and a plurality of conductive transport layers, the conductive transport layers facing the second doped regions and located on the surface of the tunneling dielectric layer, each conductive transport layer being located between adjacent doped conductive layers and in contact with the side of the doped conductive layer.

[0006] In some embodiments, the doping concentration of the second doped region is less than or equal to the doping concentration of the third doped region.

[0007] In some embodiments, the doping depth of the first doped region is less than the doping depth of the second doped region along a direction perpendicular to the first surface.

[0008] In some embodiments, along a direction perpendicular to the first surface, the doping depth of the second doped region is less than or equal to the doping depth of the third doped region.

[0009] In some embodiments, the doping depth of the first doped region is 30 nm to 300 nm; the doping depth of the second doped region is 50 nm to 500 nm; and the doping depth of the third doped region is 200 nm to 1500 nm.

[0010] In some embodiments, the doping concentration of the first doped region is 5E19 to 1E21 cm⁻¹. -3 The doping concentration of the second doped region is 1E20~3E21cm. -3 The doping concentration of the third doped region is 5E17~1E20cm⁻¹ -3 .

[0011] In some embodiments, the total doping amount of the first doped region is less than the total doping amount of the second doped region and less than the total doping amount of the third doped region.

[0012] In some embodiments, the type of dopant element in the doped conductive layer is the same as the type of dopant element in the doped layer; the doping concentration of the doped layer is less than the doping concentration of the doped conductive layer.

[0013] In some embodiments, the type of dopant element in the conductive transport layer is the same as the type of dopant element in the doped layer.

[0014] In some embodiments, the doping concentration of the conductive transport layer is greater than the doping concentration of the doped layer.

[0015] In some embodiments, along a first direction, the conductive transport layer includes spaced-apart main portions and connecting portions located between adjacent main portions, the main portions being in contact with the side of the doped conductive layer, and the doping concentration of the main portions being less than or equal to the doping concentration of the connecting portions.

[0016] In some embodiments, the second doped region includes a first sub-doped region and a second sub-doped region. The first sub-doped region is directly opposite the main body region, and the second sub-doped region corresponds one-to-one with the connecting region. The doping concentration of the first sub-doped region is less than or equal to the doping concentration of the second sub-doped region.

[0017] In some embodiments, along a direction perpendicular to the first surface, the doping depth of the first sub-doped portion is less than or equal to the doping depth of the second sub-doped portion.

[0018] In some embodiments, the ratio of the total area of ​​the connection portion to the area of ​​the conductive transport layer is 1:11 to 2:3.

[0019] In some embodiments, the material of the doped layer is at least one of monocrystalline silicon, microcrystalline silicon, amorphous silicon, or polycrystalline silicon.

[0020] In some embodiments, the material of the doped layer is the same as at least one of the material of the substrate, the material of the doped conductive layer, or the material of the conductive transport layer.

[0021] In some embodiments, the system further includes a passivation layer located on the surface of the doped conductive layer, the conductive transport layer, and the third doped region.

[0022] In some embodiments, the device further includes: a plurality of second electrodes spaced apart along a second direction, the second electrodes extending along a first direction and electrically connected to a plurality of first electrodes spaced apart along the first direction.

[0023] In some embodiments, at least one conductive transport layer is provided between adjacent second electrodes; the system further includes a conductive connection layer located between the conductive transport layer and the second electrode, wherein opposite sides of the conductive connection layer are in contact with the side of the conductive transport layer and the surface of the second electrode, respectively.

[0024] In some embodiments, the doped layer further includes a fourth doped region, which is opposite to the conductive connection layer, and the doping concentration of the fourth doped region is greater than or equal to the doping concentration of the first doped region and less than or equal to the doping concentration of the third doped region.

[0025] According to some embodiments of this application, another aspect of this application provides a photovoltaic module, characterized in that it includes: a battery string, the battery string being formed by connecting a plurality of solar cells as described in any of the above embodiments; an encapsulation layer for covering the surface of the battery string; and a cover plate for covering the surface of the encapsulation layer away from the battery string.

[0026] The technical solution provided in this application has at least the following advantages:

[0027] In the technical solution provided in this application embodiment, a doped layer is formed on the surface of the substrate. The doped layer includes a first doped region, a second doped region, and a third doped region. The first doped region has a doped conductive layer and a first electrode, the second doped region has a conductive transport layer, and the third doped region has neither a first electrode nor a doped conductive layer. To improve the contact between the doped conductive layer and the first electrode, the doped conductive layer is usually highly doped. In this application embodiment, the doping concentration of the first doped region is lower than that of the second doped region and lower than that of the third doped region. On the one hand, this avoids the possibility that an excessively high concentration of doped elements below the first electrode could lead to a contraction of the substrate's bandgap, resulting in a decrease in the open-circuit voltage of the solar cell and potentially a decline in the electric field. On the other hand, it avoids the high doping effect (such as recombination current caused by tunneling) caused by an excessively high doping concentration in the conductive layer and the doped layer. However, setting a second doped region and a third doped region with a higher doping concentration can improve the carrier transport efficiency in the region not directly opposite the first electrode, thereby increasing the open-circuit voltage of the solar cell and improving the photoelectric conversion efficiency of the solar cell.

[0028] Furthermore, the doping concentration of the doped layer is greater than that of the substrate, forming a high-low junction between the doped layer and the substrate. This creates a built-in electric field between the doped layer and the substrate. The surface of the more doped layer forms a positive space charge, while the surface of the less doped substrate forms a negative space charge. This facilitates the drift of majority carriers from the substrate to the more doped layer, which is beneficial for increasing the battery's output current. Simultaneously, due to the presence of the built-in electric field, a potential barrier exists between the substrate and the doped layer, preventing the drift of more doped majority carriers to the less doped substrate. Attached Figure Description

[0029] One or more embodiments are illustrated by way of example with reference to the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Unless otherwise stated, the drawings in the accompanying drawings do not constitute a limitation on scale. In order to more clearly illustrate the technical solutions in the embodiments of this application or in the conventional art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is a schematic diagram of the structure of a solar cell provided in one embodiment of this application;

[0031] Figure 2 This is a schematic diagram of the structure of a doped layer in a solar cell provided in an embodiment of this application;

[0032] Figure 3This is a partial cross-sectional structural diagram of a solar cell provided in an embodiment of this application;

[0033] Figure 4 This is a schematic diagram of another partial cross-sectional structure of a solar cell provided in an embodiment of this application;

[0034] Figure 5 This is a partial cross-sectional structural schematic diagram of a solar cell provided in an embodiment of this application;

[0035] Figure 6 This application provides a schematic diagram of carrier transport in a solar cell according to an embodiment of the present application.

[0036] Figure 7 This application provides a schematic diagram of carrier transport in one type of solar cell, as an embodiment of the present application.

[0037] Figure 8 This is a schematic diagram of carrier transport in yet another type of solar cell, provided as an embodiment of the present application;

[0038] Figure 9 An ECV doping concentration curve of a doped layer in a solar cell provided in one embodiment of this application;

[0039] Figure 10 This is a partial cross-sectional structural diagram of another solar cell provided in an embodiment of this application;

[0040] Figure 11 This is a schematic diagram of the structure of another solar cell provided in an embodiment of this application;

[0041] Figure 12 This is a schematic diagram of the structure of the doped layer in another solar cell provided in an embodiment of this application;

[0042] Figure 13 This is a partial cross-sectional structural schematic diagram of another solar cell provided in an embodiment of the present application;

[0043] Figure 14 This is a schematic diagram of a photovoltaic module provided in another embodiment of this application. Detailed Implementation

[0044] As can be seen from the background technology, the photoelectric conversion efficiency of current solar cells is not good.

[0045] Analysis reveals that one of the reasons for the current poor photoelectric conversion efficiency of solar cells is that, in order to improve the photoelectric conversion efficiency of solar cells, the doping concentration of the substrate is usually increased to improve the transport rate of majority carriers. However, a doped conductive layer with a high doping concentration is usually placed in the region directly opposite the electrode. When the doping concentrations of both are equally high, it may cause the bandgap of the substrate in the region directly opposite the electrode to shrink, resulting in a decrease in the open-circuit voltage of the solar cell and potentially leading to electric field degradation. Moreover, a high doping concentration can also lead to a heavy doping effect, which may result in dark current or recombination current of majority carriers due to tunneling effect, thereby reducing the short-circuit current.

[0046] This application provides a solar cell by forming a doped layer on the surface of a substrate. The doped layer includes a first doped region, a second doped region, and a third doped region. The first doped region has a doped conductive layer and a first electrode, the second doped region has a conductive transport layer, and the third doped region has neither a first electrode nor a doped conductive layer. To improve the contact between the doped conductive layer and the first electrode, the doped conductive layer is usually highly doped. In this application, the doping concentration of the first doped region is lower than that of the second doped region and lower than that of the third doped region. This avoids the possibility that an excessively high concentration of doped elements below the first electrode could cause the bandgap of the substrate to shrink, leading to a decrease in the open-circuit voltage of the solar cell and potentially causing electric field degradation. Secondly, it avoids the high doping effects (such as recombination current caused by tunneling) caused by an excessively high doping concentration in the conductive layer and the doped layer. However, setting a second and third doped region with a higher doping concentration can improve the carrier transport efficiency in the region not directly opposite the first electrode, thereby increasing the open-circuit voltage of the solar cell and improving the photoelectric conversion efficiency of the solar cell.

[0047] The embodiments of this application will now be described in detail with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details have been provided in the embodiments of this application to facilitate a better understanding of the application. However, the technical solutions claimed in this application can be implemented even without these technical details and various variations and modifications based on the following embodiments.

[0048] Figure 1 This is a schematic diagram of the structure of a solar cell provided in one embodiment of this application; Figure 2 This is a schematic diagram of the structure of a doped layer in a solar cell provided in an embodiment of this application; Figure 3 This is a partial cross-sectional structural diagram of a solar cell provided in an embodiment of this application; Figure 4 This is a schematic diagram of another partial cross-sectional structure of a solar cell provided in an embodiment of this application; Figure 5This is a partial cross-sectional structural schematic diagram of a solar cell provided in an embodiment of this application;

[0049] Figure 6 This application provides a schematic diagram of carrier transport in a solar cell according to an embodiment of the present application. Figure 7 This application provides a schematic diagram of carrier transport in one type of solar cell, as an embodiment of the present application.

[0050] Figure 8 This is a schematic diagram of carrier transport in yet another type of solar cell, provided as an embodiment of the present application; Figure 9 This is an ECV doping concentration curve of a doped layer in a solar cell provided in one embodiment of this application. Figure 3 as well as Figure 6 for Figure 1 A schematic diagram of the cross-sectional structure along the A1-A2 direction. Figure 4 as well as Figure 7 for Figure 1 A schematic diagram of the cross-sectional structure along the B1-B2 direction. Figure 5 as well as Figure 8 for Figure 1 A schematic diagram of the cross-sectional structure along the C1-C2 direction.

[0051] refer to Figures 1 to 8A solar cell includes: a substrate 100; a doped layer 110 located on a first surface of the substrate 100 adjacent to the substrate 100, wherein the doped element type in the doped layer 110 is the same as that in the substrate 100, and the doping concentration of the doped layer 110 is greater than that of the substrate 100; the doped layer 110 includes a plurality of first doped regions 111 spaced apart along a first direction Y, second doped regions 112 and third doped regions 113 located between adjacent first doped regions 111, wherein the doping concentration of the first doped regions 111 is less than that of the second doped regions 112 and less than that of the third doped regions 113; and a tunneling dielectric layer 101 located on the surface of the first doped regions 111 and the second doped regions 113. The surface of the doped region 112 includes: a plurality of doped conductive layers 102 spaced apart along a first direction Y, the doped conductive layers 102 facing the first doped region 111 and located on the surface of the tunneling dielectric layer 101; a plurality of first electrodes 103 spaced apart along the first direction Y, the first electrodes 103 extending along a second direction X, each first electrode 103 being disposed on the side of the doped conductive layer 102 away from the substrate 100 and electrically connected to the doped conductive layer 102; and a plurality of conductive transport layers 104 facing the second doped region 112 and located on the surface of the tunneling dielectric layer 101, each conductive transport layer 104 being located between adjacent doped conductive layers 102 and in contact with the side of the doped conductive layer 102.

[0052] The substrate 100 is used to receive incident light and generate photogenerated carriers. In some embodiments, the material of the substrate 100 may include at least one of monocrystalline silicon, polycrystalline silicon, amorphous silicon, or microcrystalline silicon. In other embodiments, the material of the substrate 100 may also be silicon carbide, organic materials, or multi-component compounds. Multi-component compounds may include, but are not limited to, materials such as perovskite, gallium arsenide, cadmium telluride, and copper indium selenide.

[0053] In some embodiments, the substrate 100 contains dopant elements of either N-type or P-type. N-type elements can be Group V elements such as phosphorus (P), bismuth (Bi), antimony (Sb), or arsenic (As), while P-type elements can be Group III elements such as boron (B), aluminum (Al), gallium (Ga), or indium (In). For example, when the substrate 100 is a P-type substrate, the internal dopant element type is P-type. Alternatively, when the substrate 100 is an N-type substrate, the internal dopant element type is N-type. Specifically, in some embodiments, the substrate 100 can be an N-type substrate, and the substrate 100 can be doped with N-type dopant ions, such as any one of phosphorus ions, bismuth ions, antimony ions, or arsenic ions.

[0054] In some embodiments, the solar cell is a TOPCON (Tunnel Oxide Passivated Contact) cell, and the substrate 100 further includes a second surface disposed opposite to the first surface. Both the first and second surfaces of the substrate 100 can be used to receive incident light or reflect light. In some embodiments, the first surface can be the back surface of the substrate 100, and the second surface can be the front surface of the substrate 100. In other embodiments, the first surface can also be the front surface of the substrate 100, in which case the second surface is the back surface of the substrate 100.

[0055] In some embodiments, the first surface of the substrate 100 can be configured as a non-pyramidal textured surface, such as a layered stepped morphology, to give the tunneling dielectric layer 101 located on the first surface of the substrate 100 higher density and uniformity, thereby enabling the tunneling dielectric layer 101 to have a good passivation effect on the first surface of the substrate 100. The second surface of the substrate 100 can be configured as a pyramidal textured surface to give the second surface of the substrate 100 lower reflectivity to incident light, thereby increasing the light absorption and utilization rate.

[0056] In some embodiments, the material of the doped layer 110 is at least one of monocrystalline silicon, microcrystalline silicon, amorphous silicon, or polycrystalline silicon.

[0057] The material of the doped layer 110 is the same as at least one of the materials of the substrate 100, the doped conductive layer 102, or the conductive transport layer 104. In some embodiments, when the material of the doped layer 110 is the same as the material of the substrate 100, the doped layer 110 and the substrate 100 can be considered as the same original substrate. The doped layer 110 is located in the region of the original substrate adjacent to the first surface, and the upper surfaces of the first doped region 111, the second doped region 112, and the third doped region 113 in the doped layer 110 are flush. The fact that the material of the doped layer 110 is the same as the material of the substrate 100 avoids the consumption of photogenerated carriers due to the different conductivity of the materials. There are no interface state defects between the doped layer 110 and the substrate 100, which could lead to partial carrier recombination and reduced battery efficiency. In other embodiments, the lower surfaces of the first doped region 111, the second doped region 112, and the third doped region 113 are flush.

[0058] In some embodiments, the doped layer is also a diffusion layer, which can be formed by a separate diffusion process (direct doping on the surface of the doped layer), or by the doping element penetrating into the substrate during the diffusion process when forming the doped conductive layer and the conductive transport layer to form a doped layer with a higher doping concentration than the substrate, or by a combination of both.

[0059] Furthermore, the open-circuit voltage is related to the bandgap width Eg of the material. The closer the Fermi level of the material is to the top of the conduction band and the top of the full band, the higher the built-in barrier voltage of the PN junction, and thus the larger the open-circuit voltage. The easier it is for the charge carriers to jump. When the doped layer 110 and the substrate 100 are made of different materials, the charge carriers need to jump to the interface barrier region between the substrate 100 and the doped layer 110, as well as the interface barrier region between the doped layer 110 and the tunneling dielectric layer 101, which consumes a lot of charge carriers. Moreover, the bandgap width of each material is different, that is, the open-circuit voltage is also different. The mobility of charge carriers in different materials is also different, which may affect the battery efficiency.

[0060] It is understandable that, since the doping concentration of the third doped region 113 is greater than that of the first doped region 111 and the second doped region 112, the laser processing time for the third doped region 113 is longer than that for the second doped region 112 and the first doped region 111 when laser doping is used. As a result, the upper surface of the third doped region 113 away from the substrate 100 is lower than that of the upper surface of the second doped region 112 and the first doped region 111.

[0061] In some embodiments, reference Figures 6-8 The doping concentration of the doped layer 110 is greater than that of the substrate 100, forming a high-low junction between the doped layer 110 and the substrate 100. This creates a built-in electric field between the doped layer 110 and the substrate 100. A positive space charge forms on the surface of the more doped layer 110, while a negative space charge forms on the surface of the less doped substrate 100. This facilitates the drift of majority carriers from the substrate 100 to the more doped layer 110, which is beneficial for increasing the battery's output current. Simultaneously, due to the presence of the built-in electric field, a potential barrier exists between the substrate 100 and the doped layer 110, preventing the drift of more doped majority carriers to the less doped substrate 100.

[0062] In some embodiments, along the first direction Y, the second doped region 112 is located between adjacent first doped regions 111, and the third doper is located between adjacent first doped regions 111; along the second direction X, the second doped region 112 and the third doped region 113 are arranged at intervals.

[0063] The total doping amount in the first doped region is less than the total doping amount in the second doped region and less than the total doping amount in the third doped region. The total doping amount in the first doped region 111 can be understood as the total amount of doped elements in the first doped region 111, and the total doping amount is related to the doping concentration and doping depth. Similarly, the total doping amount in the second doped region 112 can be understood as the total amount of doped elements in the second doped region 112, and the total doping amount in the third doped region 113 can be understood as the total amount of doped elements in the third doped region 113. The statement that the total doping amount of the first doped region 111 is less than the total doping amount of the second doped region 112 and less than the total doping amount of the third doped region 113 means that the doping concentration of the first doped region 111 is less than the doping concentration of the second doped region 112 and less than the doping concentration of the third doped region 113, or the doping depth of the first doped region 111 is less than the doping depth of the second doped region 112 and less than the doping depth of the third doped region 113; or, the doping concentration of the first doped region 111 is less than the doping concentration of the second doped region 112 and less than the doping concentration of the third doped region 113, and the doping depth of the first doped region 111 is less than the doping depth of the second doped region 112 and less than the doping depth of the third doped region 113. In conventional techniques, to improve the contact between the doped conductive layer 102 and the first electrode 103, the doped conductive layer 102 is usually highly doped. In this embodiment, the total doping concentration of the first doped region 111 is less than that of the second doped region 112 and less than that of the third doped region 113. This avoids the possibility that excessive doping concentration below the first electrode 103 could lead to a contraction of the bandgap of the substrate 100, resulting in a decrease in the open-circuit voltage of the solar cell and potentially a decline in the electric field. Secondly, it avoids the high doping effects (such as recombination current caused by tunneling) that result from excessive doping concentration in the conductive layer 102 and the doped layer 110. However, setting the second doped region 112 and the third doped region 113 with higher doping concentrations can improve the carrier transport efficiency in the region not directly opposite the first electrode 103, thereby increasing the open-circuit voltage of the solar cell and improving the photoelectric conversion efficiency of the solar cell.

[0064] In some embodiments, reference Figure 9 The doping depth of the first doped region 111 is 30 nm to 300 nm, preferably 50 nm to 280 nm, specifically 59 nm, 103 nm, 159 nm, 213 nm, or 280 nm. The doping concentration of the first doped region is 5E19 to 1E21 cm⁻¹. -3 Optionally, the doping concentration of the first doped region 111 is 8E19~9E20cm⁻¹. -3 Specifically, it can be 9E19cm -3 1.2E20cm -3 4.5E20cm-3 7.8E20cm -3 Or 9E20cm -3 .

[0065] In some embodiments, the doping depth of the second doped region 112 is 50 nm to 500 nm, preferably 70 nm to 450 nm, specifically 73 nm, 180 nm, 261 nm, 379 nm, or 450 nm. The doping concentration of the second doped region 112 is 1E20 to 3E21 cm⁻¹. -3 Optionally, the doping concentration of the second doped region 112 is 2E20 to 2.5E21 cm⁻¹. -3 Specifically, it can be 2E20cm -3 5E20cm -3 8E20cm -3 1.6E21cm -3 Or 2.5E21cm -3 .

[0066] In some embodiments, the doping depth of the third doped region 113 is 200 nm to 1500 nm, preferably 250 nm to 1300 nm, specifically 260 nm, 580 nm, 931 nm, 1060 nm, or 1290 nm. The doping concentration of the third doped region 113 is 5E17 to 1E20 cm⁻¹. -3 Optionally, the doping concentration of the third doped region 113 is 6E17 to 1E20 cm⁻¹. -3 Specifically, it can be 6E17cm -3 4E18cm -3 1E19cm -3 8.3E19cm -3 Or 1E20cm -3 .

[0067] In some embodiments, the total doping amount of the second doped region 112 is less than or equal to the total doping amount of the third doped region 113, including: the doping concentration of the second doped region 112 is less than or equal to the doping concentration of the third doped region 113 or the doping depth of the second doped region 112 is less than or equal to the doping depth of the third doped region 113; or, the doping concentration of the second doped region 112 is less than or equal to the doping concentration of the third doped region 113 and the doping depth of the second doped region 112 is less than or equal to the doping depth of the third doped region 113. The conductive transport layer 104 is located between adjacent doped conductive layers 102. The conductive transport layer 104 is used to improve the transmission capability of the battery and is in direct contact with the side of the doped conductive layer 102. The low doping of the second doped region 112 opposite to the doped conductive layer 102 can avoid high doping effects (e.g., recombination current generated by tunneling).

[0068] In some embodiments, the tunneling dielectric layer 101 and the doped conductive layer 102 can be used to form a passivation contact structure on the surface of the substrate 100. By forming the tunneling dielectric layer 101 and the doped conductive layer 102, the recombination of charge carriers on the surface of the substrate 100 can be reduced, thereby increasing the open-circuit voltage of the solar cell and improving the photoelectric conversion efficiency of the solar cell. Specifically, the tunneling dielectric layer 101 can reduce the defect state concentration on the first surface of the substrate 100, thereby reducing the recombination centers on the first surface of the substrate 100 and thus reducing the recombination rate of charge carriers.

[0069] The doped conductive layer 102 is used to form a field passivation layer, allowing minority carriers to escape from the interface, thereby reducing the minority carrier concentration and resulting in a lower carrier recombination rate at the interface of the substrate 100. This leads to a larger open-circuit voltage, short-circuit current, and fill factor of the solar cell, thus improving the photoelectric conversion performance of the solar cell. In some embodiments, the doped conductive layer 102 and the substrate 100 have doping elements of the same conductivity type.

[0070] Multiple doped conductive layers 102 extend along a second direction X, and are spaced apart along a first direction Y, which is perpendicular to the second direction X. In some embodiments, the first electrode 103 and the doped conductive layer 102 have a one-to-one correspondence, meaning one first electrode 103 is electrically connected to one doped conductive layer 102. That is, the doped conductive layer 102 is only disposed in the region corresponding to the first electrode 103, thereby reducing parasitic absorption in the region where the first electrode 103 is not disposed and improving the light utilization efficiency of the substrate 100. In some embodiments, the material of the first electrode 103 can be at least one of silver, aluminum, copper, tin, gold, lead, or nickel.

[0071] The tunneling dielectric layer 101 and the doped conductive layer 102 are stacked. Specifically, in some embodiments, the tunneling dielectric layer 101 can cover the entire first surface of the substrate 100, and multiple doped conductive layers 102 are spaced apart on the top surface of the tunneling dielectric layer 101. In other embodiments, the tunneling dielectric layer 101 and the doped conductive layer 102 are correspondingly arranged, that is, the tunneling dielectric layer 101 is disposed between the doped conductive layer 102 and the substrate 100, and the tunneling dielectric layer 101 is also located between the conductive transport layer 104 and the substrate 100, so that this part of the tunneling dielectric layer 101 can reduce carrier recombination on the first surface of the substrate 100, thereby increasing the carrier concentration transported to the conductive transport layer 104.

[0072] In some embodiments, the material of the tunneling dielectric layer 101 may include, but is not limited to, dielectric materials with tunneling properties such as alumina, silicon oxide, silicon nitride, silicon oxynitride, intrinsic amorphous silicon, and intrinsic polycrystalline silicon. Specifically, the tunneling dielectric layer 101 may be formed of a silicon oxide layer including silicon oxide (SiOx), which has good passivation properties and allows charge carriers to easily tunnel through the silicon oxide layer.

[0073] In some embodiments, the material of the conductive transport layer 104 is the same as the material of the doped conductive layer 102. By using the same material for the conductive transport layer 104 and the doped conductive layer 102, the number of material types in the entire production process can be reduced, facilitating management. Furthermore, using the same material for the conductive transport layer 104 and the doped conductive layer 102 ensures good contact between them, resulting in better carrier transport at the interface and reducing transport losses. Additionally, it allows the carrier transport rates in the conductive transport layer 104 and the doped conductive layer 102 to be similar or the same, thereby improving the transport efficiency of carriers from the conductive transport layer 104 to the doped conductive layer 102. It is worth noting that "same material" here refers to the conductive transport layer 104 having the same type and concentration of dopant ions as the doped conductive layer 102.

[0074] Specifically, in some embodiments, the material of the doped conductive layer 102 is at least one of doped amorphous silicon, doped polycrystalline silicon, or doped microcrystalline silicon. Correspondingly, the material of the conductive transport layer 104 may also be one of doped amorphous silicon, doped polycrystalline silicon, or doped microcrystalline silicon.

[0075] It is understood that in other embodiments, the material of the conductive transport layer 104 may also be different from the material of the doped conductive layer 102. For example, the material of the conductive transport layer 104 may be one of doped amorphous silicon, doped polycrystalline silicon, or doped microcrystalline silicon, and the material of the doped conductive layer 102 may be another of doped amorphous silicon, doped polycrystalline silicon, or doped microcrystalline silicon.

[0076] In some embodiments, when the material of the conductive transport layer 104 is different from the material of the doped conductive layer 102, the absorption coefficient of the material of the conductive transport layer 104 to incident light can be set to be smaller than the absorption coefficient of the conductive transport layer 104 to incident light. This can improve the lateral transport capability of charge carriers while reducing the absorption capability of the conductive transport layer 104 to incident light, thereby improving the utilization rate of incident light by the solar cell.

[0077] In some embodiments, there are multiple conductive transport layers 104, which are arranged at intervals along the second direction X. The multiple conductive transport layers 104 are disposed between two adjacent doped conductive layers 102, allowing majority carriers in the substrate 100 to be transported to the doped conductive layers 102 through the multiple conductive transport layers 104, thereby enhancing the lateral transport capability of majority carriers in the substrate 100. Furthermore, the multiple conductive transport layers 104 are arranged at intervals, meaning that the conductive transport layers 104 do not cover the entire area between two adjacent doped conductive layers 102, but are disposed in localized areas between two adjacent doped conductive layers 102. Thus, when the material of the conductive transport layers 104 is the same as the material of the doped conductive layers 102, the overall area of ​​the conductive transport layers 104 is not excessively large, thereby preventing the substrate 100 from having low utilization of incident light due to excessive absorption of incident light by the conductive transport layers 104.

[0078] In some embodiments, a plurality of conductive transport layers 104 are arranged in an array, including: multiple columns of conductive transport layers 104 spaced apart along a first direction Y, wherein the plurality of conductive transport layers 104 in each column are spaced apart along a second direction X, and at least one first electrode 103 is provided between two adjacent columns of conductive transport layers 104 along the first direction Y. That is, in some embodiments, when there is only one first electrode 103 between adjacent conductive transport layers 104, there is a conductive transport layer 104 between every two adjacent first electrodes 103. In other embodiments, there may also be multiple first electrodes 103 between two adjacent columns of conductive transport layers 104, such that there is a conductive transport layer 104 between some of the two adjacent first electrodes 103, and no conductive transport layer 104 between some of the adjacent first electrodes 103. For example, in the second direction X, there is a conductive transport layer 104 between the first first electrode 103 and the second first electrode 103, but no conductive transport layer 104 between the second first electrode 103 and the third first electrode 103. It is understandable that when the material of the conductive transport layer 104 is the same as that of the doped conductive layer 102, the more conductive transport layers 104 there are, the stronger the absorption capacity of incident light will be while enhancing the lateral capacity of charge carriers. Therefore, the connection relationship between the conductive transport layer 104 and the doped conductive layer 102 can be flexibly set based on the total number of first electrodes 103 and the requirements for the current collection capacity of the first electrodes 103, so that while improving the charge carrier transport capacity, the conductive transport layer 104 will not have a strong absorption effect on incident light.

[0079] refer to Figure 1In some embodiments, a conductive transport layer 104 is provided between all adjacent first electrodes 103. Providing a conductive transport layer 104 between every two first electrodes 103 can improve the lateral transport capability between adjacent first electrodes 103, thereby improving the current collection capability of each first electrode 103.

[0080] In some embodiments, each conductive transport layer 104 in a column of conductive transport layers 104 corresponds one-to-one with each conductive transport layer 104 in an adjacent column of conductive transport layers 104, and the corresponding two conductive transport layers 104 are spaced apart along the first direction Y. For example, each conductive transport layer 104 in the first column of conductive transport layers 104 is aligned with the corresponding conductive transport layer 104 in the second column of conductive transport layers 104 in the first direction Y, and each column of conductive transport layers 104 is regularly arranged. This results in a large number of conductive transport layers 104, thereby forming more lateral transport channels for the lateral transport of charge carriers in the substrate 100. Furthermore, since each column of conductive transport layers 104 is regularly arranged, the process of forming the conductive transport layers 104 can be simplified in the actual fabrication process.

[0081] In other embodiments, a column of conductive transport layers 104 is staggered with an adjacent column of conductive transport layers 104 along the second direction X. That is, each conductive transport layer 104 in the first column and each conductive transport layer 104 in the second column are not directly opposite each other in the first direction Y; in other words, each conductive transport layer 104 in the first column and each conductive transport layer 104 in the second column are staggered in the second direction X. This staggered arrangement of multiple conductive transport layers 104 prevents the number of conductive transport layers 104 from becoming excessive, thus avoiding excessive absorption of incident light by each conductive transport layer 104. Furthermore, it allows for a smaller number of conductive transport layers 104 while ensuring uniform distribution of the conductive transport layers 104 on the first surface of the substrate 100, thereby enhancing the lateral transport capability of charge carriers at different locations within the substrate 100.

[0082] In some embodiments, along the second direction X, the density of the conductive transport layer 104 near the edge of the substrate 100 is greater than the density of the conductive transport layer 104 away from the edge of the substrate 100. For example, the spacing of the conductive transport layer 104 near the edge of the substrate 100 in the second direction X is smaller than the spacing of the conductive transport layer 104 away from the edge of the substrate 100 in the second direction X. Thus, the density of the conductive transport layer 104 near the edge of the substrate 100 is greater than that away from the edge of the substrate 100, meaning that the lateral transport capability of the charge carriers in the substrate 100 corresponding to the edge of the substrate 100 is stronger, resulting in a larger charge carrier concentration in the first electrode 103 near the edge of the substrate 100. This compensates for the number of charge carriers collected by the outermost second electrode 106, improving the current collection capability of the outermost second electrode 106.

[0083] In some embodiments, the top surface of the conductive transport layer 104 is lower than or flush with the top surface of the doped conductive layer 102. Setting the top surface of the conductive transport layer 104 to be no higher than the top surface of the doped conductive layer 102 prevents the absorption of incident light by the sides of the conductive transport layer 104 due to the top surface of the conductive transport layer 104 protruding from the top surface of the doped conductive layer 102, thereby reducing the parasitic absorption capacity of the conductive transport layer 104 for incident light. In the direction perpendicular to the surface of the substrate 100, the height of the conductive transport layer 104 can be 0.5 to 1.2 times the height of the doped conductive layer 102.

[0084] In some embodiments, reference Figure 6 as well as Figure 7 The doped element type in the conductive layer is the same as that in the doped layer 110; the doping concentration of the doped layer 110 is less than that of the doped conductive layer 102. A high-low junction is formed between the doped layer 110 and the substrate 100, forming a first built-in electric field between them; a high-low junction is also formed between the doped layer 110 and the doped conductive layer 102, forming a second built-in electric field between them. The voltage orientations of the first and second built-in electric fields are the same, creating a dual voltage difference. The majority carriers tending towards the substrate 100 easily drift to the highly doped layer 110, then drift again to the doped conductive layer 102, and are finally collected by the first electrode 103, which helps to increase the output current of the battery. Meanwhile, due to the presence of the built-in electric field, there is a potential barrier between the substrate 100 and the doped layer 110, and a potential barrier between the doped layer 110 and the doped conductive layer 102, thereby preventing the highly doped majority carriers from drifting to the less doped substrate 100.

[0085] Similarly, refer to Figure 8The doping element type in the conductive transport layer 104 is the same as that in the doped layer 110; the doping concentration of the conductive transport layer 104 is greater than that of the doped layer 110. A high-low junction is formed between the doped layer 110 and the conductive transport layer 104, creating a third built-in electric field. The voltage orientations of the first and third built-in electric fields are the same, forming a dual voltage difference. The majority carriers in the substrate 100 tend to drift to the highly doped doped layer 110, then drift to the conductive transport layer 104, and then to the doped conductive layer 102, finally being collected by the first electrode 103, which helps to increase the output current of the battery. At the same time, the presence of the built-in electric field can prevent the highly doped majority carriers from drifting to the less doped substrate 100.

[0086] Figure 10 This is a partial cross-sectional structural diagram of another solar cell provided in an embodiment of this application.

[0087] In some embodiments, reference Figure 10 Along the first direction Y, the conductive transport layer 104 includes spaced-apart main body portions 121 and connecting portions 122 located between adjacent main body portions 121. The main body portions 121 are in side contact with the doped conductive layer 102, and the doping concentration of the main body portions 121 is less than or equal to the doping concentration of the connecting portions 122. Since the conductive transport layer 104 serves as a lateral transport channel for charge carriers, the doped conductive layer 102 adjacent to the conductive transport layer 104 has a higher charge carrier concentration. This results in a higher charge carrier concentration in the portion of the first electrode 103 that is electrically connected to the doped conductive layer 102 adjacent to the conductive transport layer 104 (main body portion 121), thereby improving the current collection capability of the first electrode 103. At the same time, the doping concentration at the connecting portions 122 is lower, resulting in less light absorption, thus avoiding the problem of excessive absorption of incident light by the conductive transport layer 104, thereby improving the overall photoelectric conversion performance of the solar cell.

[0088] In some embodiments, the ratio of the total area of ​​the connection portion 122 to the area of ​​the conductive transport layer 104 is 1:11 to 2:3. Optionally, the ratio is 1 / 3 to 2 / 3, specifically 0.4, 0.48, 0.56, or 0.62. A larger area ratio of the main body portion 121 can enhance the current collection capability of the first electrode 103, while reducing light absorption and improving battery efficiency. A larger area ratio of the connection portion 122 enhances the lateral transport capability of charge carriers.

[0089] In some embodiments, the top surface of the connector 122 has a light-trapping structure. The light-trapping structure enhances the reflectivity of the top surface of the conductive transport layer 104 towards incident light, thereby reflecting incident light onto the top surface of the conductive transport layer 104 and preventing it from being absorbed by the conductive transport layer 104. This reflected incident light can also be reflected back, for example, to areas not covered by the doped conductive layer 102 and the conductive transport layer 104, and then absorbed and utilized by the substrate 100. This enhances the absorption and utilization rate of the incident light by the substrate 100.

[0090] In some embodiments, the cross-sectional shape of the connecting portion 122 along the direction perpendicular to the first surface includes a triangle, rectangle, trapezoid, or ellipse, and the top surface of the connecting portion 122 is lower than the top surface of the main body portion 121, thereby allowing the doped conductive layer 102 to provide a certain degree of shielding against incident light irradiating the top surface of the conductive transport layer 104. On the other hand, it also allows the incident light to undergo multiple reflections on the sidewalls of the connecting portion 122, thereby reducing the parasitic absorption of incident light by the top surface of the conductive doped layer 110. It is understood that in other embodiments, the cross-sectional shape of the connecting portion 122 can also be other shapes, as long as it satisfies the feature that the top surface of the connecting portion is recessed towards the substrate 100.

[0091] In some embodiments, the second doped region 112 includes a first sub-doped region 131 and a second sub-doped region 132. The first sub-doped region 131 faces the main body 121, and the second sub-doped region 132 corresponds one-to-one with the connecting region 122. The doping concentration of the first sub-doped region 131 is less than or equal to the doping concentration of the second sub-doped region 132. The total doping amount of the first sub-doped region 131 is less than or equal to the total doping amount of the second sub-doped region 132. The total doping amount of the first sub-doped region 131 being less than or equal to the total doping amount of the second sub-doped region 132 includes: the doping concentration of the first sub-doped region 131 being less than or equal to the doping concentration of the second sub-doped region 132 or, along a direction perpendicular to the first surface, the doping depth of the first sub-doped region 131 being less than or equal to the doping depth of the second sub-doped region 132; or, the doping concentration of the first sub-doped region 131 being less than or equal to the doping concentration of the second sub-doped region 132 and the doping depth of the first sub-doped region 131 being less than or equal to the doping depth of the second sub-doped region 132. The connecting portion 122 is located between adjacent main portions 121. The main portions 121 are in direct contact with the side of the doped conductive layer 102. The conductive transport layer 104 is used to improve the transport capability of the battery. The low doping of the first sub-doped portion 131 opposite to the main portion 121 can avoid the high doping effect (e.g., the tunneling effect generates recombination current). The high doping of the second sub-doped portion 132 opposite to the connecting portion 122 can improve the carrier transport rate.

[0092] In some embodiments, the system further includes a passivation layer 107, which is located on the surface of the doped conductive layer 102, the conductive transport layer 104, and the third doped region 113; the passivation layer 107 can be considered as a post-passivation layer. The passivation layer 107 can be a single-layer structure or a stacked structure, and the material of the passivation layer 107 can be one or more of the following materials: silicon oxide, silicon nitride, silicon oxynitride, silicon carbonitride, titanium oxide, hafnium oxide, or aluminum oxide.

[0093] The first electrode 103 is the grid line of the solar cell, used to collect and summarize the current of the solar cell. The first electrode 103 may be sintered from a burn-through paste. The material of the first electrode 103 may be one or more of aluminum, silver, gold, nickel, molybdenum, or copper. In some cases, the first electrode 103 refers to fine grid lines or finger grid lines to distinguish it from main grid lines or busbars.

[0094] In some embodiments, the solar cell further includes: an emitter located on a second surface of the substrate 100 away from the doped layer 110, the emitter having a different doping element type than the substrate 100; a first passivation layer located on the surface of the emitter away from the substrate 100, the first passivation layer being considered as a front passivation layer; and a plurality of spaced electrodes that penetrate the first passivation layer and are in contact with the emitter.

[0095] In some embodiments, the first passivation layer may be a single-layer structure or a stacked structure, and the material of the first passivation layer may be one or more of the following materials: silicon oxide, silicon nitride, silicon oxynitride, silicon carbonitride, titanium oxide, hafnium oxide, or aluminum oxide.

[0096] The electrode is sintered from a burn-through slurry. The contact between the electrode and the emitter can be localized or complete. The electrode material can be one or more of aluminum, silver, nickel, gold, molybdenum, or copper. In some embodiments, the electrode is a top electrode or a front electrode. In some cases, the electrode refers to fine grid lines or finger grid lines, to distinguish it from main grid lines or busbars.

[0097] In some embodiments, the surface of the emitter away from the substrate 100 may also have an antireflection layer, which serves to reduce the reflection of incident light. In some embodiments, the antireflection layer may be a silicon nitride layer, which may include silicon nitride material. In other embodiments, the antireflection layer may also be a multilayer structure, such as a stacked structure made of one or more materials selected from silicon nitride, silicon oxide, or silicon oxynitride.

[0098] In other embodiments, the second surface of the substrate 100 may also have a structure similar to that of the first surface of the substrate 100. For example, the second surface of the substrate 100 may have a second tunneling dielectric layer and a second doped conductive layer stacked sequentially along the distance from the second surface of the substrate 100, wherein the dopant ion type in the second doped conductive layer is different from the dopant ion type in the doped conductive layer 102.

[0099] Figure 11 This is a schematic diagram of the structure of another solar cell provided in an embodiment of this application; Figure 12 This is a schematic diagram of the structure of the doped layer in another solar cell provided in an embodiment of this application; Figure 13 This is a partial cross-sectional structural diagram of another solar cell provided in an embodiment of this application.

[0100] In some embodiments, the solar cell further includes: a plurality of second electrodes 106 spaced apart along a second direction X, the second electrodes 106 extending along a first direction Y and electrically connected to a plurality of first electrodes 103 spaced apart along the first direction Y, for collecting current in the first electrodes 103 for convergence and outflow from the solar cell. It is understood that the second electrodes 106 are in electrical contact not only with the first electrodes 103 but also with a portion of the doped conductive layer 102. This allows charge carriers in the doped conductive layer 102 to be directly transferred to the second electrodes 106 without passing through the first electrodes 103, thereby improving the current collection capability of the second electrodes 106.

[0101] In some embodiments, at least one conductive transport layer 104 is provided between adjacent second electrodes 106, that is, the second electrodes 106 and the conductive transport layer 104 are spaced apart. Thus, the conductive transport layer 104 can limit the position of the second electrodes 106, allowing the position of the second electrodes 106 to be determined without additional positioning processing during the fabrication process, facilitating the printing of the second electrodes 106 and simplifying the process flow. The solar cell also includes a conductive connection layer 105, located between the conductive transport layer 104 and the second electrodes 106. The opposing sides of the conductive connection layer 105 are in contact with the side of the conductive transport layer 104 and the surface of the second electrodes 106, respectively, allowing the second electrodes 106 to collect current from the substrate 100 through the doped conductive layer 102 without passing through the first electrode 103.

[0102] In some embodiments, the doped layer 110 further includes a fourth doped region 114, which faces the conductive connection layer 105. The doping concentration of the fourth doped region 114 is greater than or equal to the doping concentration of the first doped region 111 and less than or equal to the doping concentration of the third doped region 113. The technical effect of the fourth doped region 114 having a doping concentration greater than or equal to the doping concentration of the first doped region 111 and less than or equal to the doping concentration of the third doped region 113 is similar to the technical effect of the first doped region 111 having a doping concentration less than the doping concentration of the second doped region 112 and less than the doping concentration of the third doped region 113, and will not be elaborated further here.

[0103] The doping depth of the fourth doping region 114 is greater than or equal to the doping depth of the first doping region 111 and less than or equal to the doping depth of the third doping region 113; and the technical effect of the doping depth of the fourth doping region 114 being greater than or equal to the doping depth of the first doping region 111 and less than or equal to the doping depth of the third doping region 113 is similar to the technical effect of the doping depth of the first doping region 111 being less than the doping depth of the second doping region 112 and less than the doping depth of the third doping region 113, and will not be elaborated further here. According to some embodiments of this application, another aspect of the embodiments of this application also provides a photovoltaic module, characterized in that it includes: a battery string, the battery string being formed by connecting a plurality of solar cells as described in any of the above embodiments; an encapsulation layer, the encapsulation layer being used to cover the surface of the battery string; and a cover plate, the cover plate being used to cover the surface of the encapsulation layer away from the battery string.

[0104] In the technical solution provided by the above embodiments, a doped layer 110 is provided on the surface of the substrate 100, and the doped layer 110 includes a first doped region 111, a second doped region 112 and a third doped region 113. The first doped region 111 has a doped conductive layer 102 and a first electrode 103, the second doped region 112 has a conductive transport layer 104, and the third doped region 113 does not have a first electrode 103 and a doped conductive layer 102. To improve the contact between the doped conductive layer 102 and the first electrode 103, the doped conductive layer 102 is typically highly doped. In this embodiment, the doping concentration of the first doped region 111 is lower than that of the second doped region 112 and the third doped region 113. This avoids the possibility that excessive doping concentration below the first electrode 103 could lead to a contraction of the bandgap of the substrate 100, resulting in a decrease in the open-circuit voltage of the solar cell and potentially causing electric field degradation. Secondly, it avoids the high doping effects (such as recombination current caused by tunneling) resulting from excessively high doping concentrations in the conductive layer 102 and the doped layer 110. However, setting higher doping concentrations in the second doped region 112 and the third doped region 113 can improve the carrier transport efficiency in the region not directly opposite the first electrode 103, thereby increasing the open-circuit voltage of the solar cell and improving its photoelectric conversion efficiency.

[0105] Figure 14 This is a schematic diagram of a photovoltaic module provided in another embodiment of this application.

[0106] This application also provides a photovoltaic module, as shown in the embodiments. Figure 14 The photovoltaic module includes a battery string, which is formed by connecting multiple solar cells 20 provided in the above embodiments; an encapsulation layer 21 for covering the surface of the battery string; and a cover plate 22 for covering the surface of the encapsulation layer 21 away from the battery string. The solar cells 20 are electrically connected in a whole or in multiple segments to form multiple battery strings, and the multiple battery strings are electrically connected in series and / or parallel.

[0107] Specifically, in some embodiments, multiple battery strings can be electrically connected. The encapsulation layer 21 includes a first encapsulation layer 211 and a second encapsulation layer 212. The first encapsulation layer 211 covers one of the front or back sides of the solar cell 20, and the second encapsulation layer covers the other of the front or back sides of the solar cell 20. Specifically, at least one of the first encapsulation layer 211 or the second encapsulation layer 212 can be an organic encapsulation film such as ethylene-vinyl acetate copolymer (EVA) film, polyethylene octene coelastomer (POE) film, or polyethylene terephthalate (PET) film. In some embodiments, the cover plate 22 can be a glass cover plate, a plastic cover plate, or a cover plate with light-transmitting function. Specifically, the surface of the cover plate 22 facing the encapsulation layer 21 can be an uneven surface, thereby increasing the utilization rate of incident light. The cover plate 22 includes a first cover plate 221 and a second cover plate 222, with the first cover plate 221 opposite to the first encapsulation layer 211 and the second cover plate 222 opposite to the second encapsulation layer 212.

[0108] While this application discloses preferred embodiments as described above, it is not intended to limit the scope of the claims. Any person skilled in the art can make various possible variations and modifications without departing from the concept of this application. Therefore, the scope of protection of this application should be determined by the scope defined in the claims. Furthermore, the embodiments and accompanying drawings in this specification are merely illustrative and do not represent the full scope of protection of the claims.

[0109] Those skilled in the art will understand that the above embodiments are specific examples of implementing this application, and in practical applications, various changes can be made in form and detail without departing from the spirit and scope of this application. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of this application; therefore, the scope of protection of this application should be determined by the scope defined in the claims.

Claims

1. A solar cell, characterized in that, include: Base; A doped layer is located within a substrate adjacent to a first surface of the substrate. The doped layer contains doped elements of the same type as the substrate. The doping concentration of the doped layer is greater than that of the substrate. The doped layer includes a plurality of first doped regions spaced apart along a first direction, a second doped region located between adjacent first doped regions, and a third doped region. The doping concentration of the first doped region is less than that of the second doped region and less than that of the third doped region. A tunneling dielectric layer is located on the surface of the first doped region and the surface of the second doped region; Multiple doped conductive layers are spaced apart along the first direction, the doped conductive layers are opposite to the first doped region, and the doped conductive layers are located on the surface of the tunneling dielectric layer; A plurality of first electrodes are spaced apart along the first direction, the first electrodes extend along the second direction, and each first electrode is disposed on the side of the doped conductive layer away from the substrate and is electrically connected to the doped conductive layer. A conductive transport layer is provided, which is opposite to the second doped region and is located on the surface of the tunneling dielectric layer. Each conductive transport layer is located between adjacent doped conductive layers and is in contact with the side of the doped conductive layer.

2. The solar cell according to claim 1, characterized in that, The doping concentration of the second doped region is less than or equal to the doping concentration of the third doped region.

3. The solar cell according to claim 1, characterized in that, Along a direction perpendicular to the first surface, the doping depth of the first doped region is less than the doping depth of the second doped region.

4. The solar cell according to claim 1 or 3, characterized in that, Along a direction perpendicular to the first surface, the doping depth of the second doped region is less than or equal to the doping depth of the third doped region.

5. The solar cell according to claim 1, characterized in that, The doping depth of the first doped region is 30nm to 300nm; the doping depth of the second doped region is 50nm to 500nm; and the doping depth of the third doped region is 200nm to 1500nm.

6. The solar cell according to claim 1, characterized in that, The doping concentration of the first doped region is 5E19~1E21cm. -3 The doping concentration of the second doped region is 1E20~3E21cm. -3 The doping concentration of the third doped region is 5E17 to 1E20 cm⁻¹. -3 .

7. The solar cell according to claim 1, characterized in that, The total doping amount in the first doped region is less than the total doping amount in the second doped region and less than the total doping amount in the third doped region.

8. The solar cell according to claim 1, characterized in that, The type of doped element in the doped conductive layer is the same as the type of doped element in the doped layer; the doping concentration of the doped layer is less than the doping concentration of the doped conductive layer.

9. The solar cell according to claim 1, characterized in that, The type of doped element in the conductive transport layer is the same as the type of doped element in the doped layer.

10. The solar cell according to claim 9, characterized in that, The doping concentration of the conductive transport layer is greater than that of the doped layer.

11. The solar cell according to claim 9, characterized in that, Along the first direction, the conductive transport layer includes spaced-apart main body portions and connecting portions located between adjacent main body portions. The main body portions are in contact with the side of the doped conductive layer, and the doping concentration of the main body portions is less than or equal to the doping concentration of the connecting portions.

12. The solar cell according to claim 11, characterized in that, The second doped region includes a first sub-doped region and a second sub-doped region. The first sub-doped region is directly opposite the main body region, and the second sub-doped region corresponds to the connecting region one by one. The doping concentration of the first sub-doped region is less than or equal to the doping concentration of the second sub-doped region.

13. The solar cell according to claim 12, characterized in that, Along a direction perpendicular to the first surface, the doping depth of the first sub-doped portion is less than or equal to the doping depth of the second sub-doped portion.

14. The solar cell according to claim 11, characterized in that, The ratio of the total area of ​​the connection portion to the area of ​​the conductive transmission layer is 1:11 to 2:

3.

15. The solar cell according to claim 1, characterized in that, The material of the doped layer is at least one of monocrystalline silicon, microcrystalline silicon, amorphous silicon, or polycrystalline silicon.

16. The solar cell according to claim 15, characterized in that, The material of the doped layer is the same as at least one of the material of the substrate, the material of the doped conductive layer, or the material of the conductive transport layer.

17. The solar cell according to claim 1, characterized in that, Also includes: A passivation layer is located on the surface of the doped conductive layer, the conductive transport layer, and the third doped region.

18. The solar cell according to claim 1, characterized in that, Also includes: A plurality of second electrodes are spaced apart along the second direction, the second electrodes extend along the first direction, and are electrically connected to a plurality of first electrodes spaced apart along the first direction.

19. The solar cell according to claim 18, characterized in that, At least one of the conductive transport layers is present between adjacent second electrodes; the system further includes a conductive connection layer located between the conductive transport layer and the second electrode, wherein opposite sides of the conductive connection layer are in contact with the side of the conductive transport layer and the surface of the second electrode, respectively.

20. The solar cell according to claim 19, characterized in that, The doped layer further includes a fourth doped region, which is directly opposite the conductive connection layer. The doping concentration of the fourth doped region is greater than or equal to the doping concentration of the first doped region and less than or equal to the doping concentration of the third doped region.

21. A photovoltaic module, characterized in that, include: A battery string, wherein the battery string is formed by connecting a plurality of solar cells as described in any one of claims 1 to 20; Encapsulation layer, the encapsulation layer being used to cover the surface of the battery string; A cover plate for covering the surface of the encapsulation layer away from the battery string.

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