Solar cell, battery assembly, and photovoltaic system

Abstract

The application relates to the technical field of solar cells, and provides a solar cell, a battery assembly and a photovoltaic system. In the solar cell, a first doping layer is doped with a first doping element, the first doping layer comprises at least one first doping region and a plurality of second doping regions in conduction with the first doping region, the plurality of second doping regions are spaced from each other, and the doping concentration of the first doping element in the first doping region is greater than the doping concentration of the first doping element in the second doping region. In the region where the first doping layer is covered by a first grid electrode, the area proportion of the first doping region is at least 35%, and in the region where the first doping layer is not covered by the first grid electrode, the area proportion of the first doping region is 5%-85%. In this way, the balance optimization of low recombination centers and low Auger recombination and carrier collection efficiency can be realized, the recombination centers are effectively reduced, the Auger recombination is reduced, the high carrier collection efficiency is ensured, and the overall performance of the solar cell is optimized.

Description

Technical Field

[0001] This application relates to the field of solar cell technology, and more particularly to a solar cell, a battery module, and a photovoltaic system. Background Technology

[0002] Solar cells convert light energy into electrical energy based on the photovoltaic effect. The core of solar cells lies in the absorption of photons by semiconductor materials to generate electron-hole pairs, and the output of current through the electrode structure.

[0003] Currently, passivated contact structures formed by stacking dielectric and doped layers are commonly used in solar cells. Specifically, a dielectric layer and a doped layer are sequentially disposed on the surface of a silicon substrate, and the grid electrodes directly contact the doped layer to form an ohmic path, thereby collecting photogenerated carriers. However, in this technical solution, when the doped layer uses a high concentration of doping, the dopant element (such as boron) can easily penetrate the dielectric layer and diffuse to the silicon substrate interface, thereby damaging the interface between the dielectric layer and the substrate and forming high-density pores. This increases the number of recombination centers, leading to intensified Auger recombination and affecting the overall performance of the cell. Conversely, if the doping concentration is set too low, the contact resistance between the grid lines and the doped layer will increase significantly, resulting in lower carrier collection efficiency, which will also affect the overall performance of the cell.

[0004] Therefore, how to achieve a balance between low recombination centers and low Auger recombination with carrier collection efficiency to improve the performance of solar cells has become a technical problem for engineers. Summary of the Invention

[0005] This application provides a solar cell, a battery module, and a photovoltaic system.

[0006] This application is implemented as follows: the solar cell in the embodiments of this application includes: A silicon substrate having opposing first and second surfaces; A first dielectric layer is stacked on the first surface; A first doped layer is stacked on the first dielectric layer, the first doped layer being doped with a first doping element, the first doped layer including at least one first doped region and a plurality of second doped regions connected to the first doped region, the plurality of second doped regions being spaced apart from each other, and the doping concentration of the first doping element in the first doped region being greater than the doping concentration of the first doping element in the second doped region; and The first gate electrode is disposed on the first doped layer and electrically connected to the first doped layer; Wherein, in the region where the first doped layer is covered by the first gate electrode, the area of ​​the first doped region accounts for at least 35%, and in the region where the first doped layer is not covered by the first gate electrode, the area of ​​the first doped region accounts for 5%-85%.

[0007] In some embodiments, the area of ​​the first doped layer covered by the first gate electrode is the first doped region.

[0008] In some embodiments, in the region where the first doped layer is not covered by the first gate electrode, the area of ​​the first doped region accounts for 25%-70%.

[0009] In some embodiments, the doping concentration of the first dopant element in the first doped region is 1E19 / cm³. 3 -1E21 / cm 3 The doping concentration of the first doped element in the second doped region is less than 1E18 / cm³. 3 .

[0010] In some embodiments, the doping concentration of the first dopant element in the second doped region is less than 1E17 / cm³. 3 .

[0011] In some embodiments, the first doped layer further includes a third doped region, the third doped region being located between the second doped region and the first doped region, and the second doped region being connected to the first doped region through the third doped region; Wherein, the doping concentration of the first doped element in the third doped region is greater than the doping concentration of the first doped element in the second doped region and less than the doping concentration of the first doped element in the first doped region.

[0012] In some embodiments, the doping concentration of the first dopant element in the third dopant region gradually decreases in the direction away from the first doped region.

[0013] In some embodiments, the width of the third doped region is 0.1 μm-8 μm.

[0014] In some embodiments, the number of the first doped regions is multiple, and the multiple first doped regions are interconnected.

[0015] In some embodiments, the size of the second doped region is 1 μm-600 μm.

[0016] In some embodiments, the conductivity type of the first doped layer is opposite to that of the silicon substrate.

[0017] In some embodiments, the first dopant element is boron.

[0018] In some embodiments, a first inner expansion layer is formed on the silicon substrate at the location corresponding to the first doped region. The first inner expansion layer is in contact with the first dielectric layer. The doping concentration of the first doping element in the first inner expansion layer is less than 20% of the doping concentration of the first doping element in the first doped region and is greater than or equal to 10 ppm.

[0019] In some embodiments, the solar cell further includes a second dielectric layer and a second doped layer, wherein the second dielectric layer is stacked on the second surface, and the second doped layer is stacked on the second dielectric layer, wherein the second doped layer is doped with a second doping element and the conductivity type of the second doped layer is opposite to that of the first doped layer; or The solar cell further includes a second dielectric layer and a second doped layer. The second dielectric layer is also stacked on the first surface, and the second doped layer is stacked on the second dielectric layer. There are multiple first doped layers and multiple second doped layers. The multiple first doped layers and multiple second doped layers are alternately arranged on the first surface along a first direction. The second doped layer is doped with a second doping element, and the conductivity type of the second doped layer is opposite to that of the first doped layer.

[0020] In some embodiments, the conductivity type of the first doped layer is opposite to that of the silicon substrate, and the conductivity type of the second doped layer is the same as that of the silicon substrate.

[0021] In some embodiments, the second doped layer includes at least one fourth doped region and a plurality of fifth doped regions connected to the fourth doped region, wherein the doping concentration of the second doped element in the fourth doped region is greater than the doping concentration of the second doped element in the fifth doped region. The solar cell also includes: The second gate electrode is disposed on the second doped layer and electrically connected to the second doped layer; Specifically, in the region where the second doped layer is covered by the second gate electrode, the area of ​​the fourth doped region accounts for at least 35%, and in the region where the second doped layer is not covered by the second gate electrode, the area of ​​the fourth doped region accounts for 5%-85%.

[0022] In some embodiments, the area of ​​the second doped layer covered by the second gate electrode is the fourth doped region.

[0023] In some embodiments, in the region where the second doped layer is not covered by the second gate electrode, the area of ​​the fourth doped region accounts for 25%-70%.

[0024] In some embodiments, the second doped layer further includes a sixth doped region, the sixth doped region being located between the fifth doped region and the fourth doped region, and the fifth doped region being connected to the fourth doped region through the sixth doped region; The doping concentration of the second doped element in the sixth doped region is greater than that in the fifth doped region but less than that in the fourth doped region.

[0025] This application also provides a battery assembly, which includes several solar cells as described in the embodiments of this application.

[0026] This application also provides a photovoltaic system, which includes the above-described battery components.

[0027] In the solar cells, battery modules, and photovoltaic systems of this application embodiment, a first dielectric layer is stacked on a first surface. A first doped layer is stacked on the first dielectric layer, and the first doped layer is doped with a first doping element. The first doped layer includes at least one first doped region and a plurality of second doped regions that are electrically connected to the first doped region. The plurality of second doped regions are spaced apart from each other, and the doping concentration of the first doping element in the first doped region is greater than the doping concentration of the first doping element in the second doped region. A first grid electrode is disposed on the first doped layer and electrically connected to the first doped layer. In the region of the first doped layer covered by the first grid electrode, the area of ​​the first doped region accounts for at least 35%, and in the region of the first doped layer not covered by the first grid electrode, the area of ​​the first doped region accounts for 5%-85%. Thus, by using a first doped region with a high doping concentration and a second doped region with a low doping concentration in the first doped layer, and precisely controlling the area ratio of the first doped region in the region covered by the first gate electrode to be at least 35%, and controlling the area ratio of the first doped region in the remaining regions to be between 5% and 85%, it is possible to reduce the interface recombination centers and Auger recombination losses in the silicon substrate while ensuring the carrier collection efficiency. That is, by performing such precise and specific optimization design on the area ratio of the high doping concentration first doped region in the electrode region and non-electrode region, a balance optimization between low recombination centers and low Auger recombination and carrier collection efficiency can be achieved. This effectively reduces recombination centers and Auger recombination while ensuring high carrier collection efficiency, thereby optimizing the overall performance of the solar cell.

[0028] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of a photovoltaic system module provided in an embodiment of this application; Figure 2 This is a schematic diagram of a battery assembly provided in an embodiment of this application; Figure 3 This is a schematic diagram of the planar structure of the solar cell provided in the embodiments of this application; Figure 4 This is another planar structural schematic diagram of the solar cell provided in the embodiments of this application; Figure 5 This is another planar structural schematic diagram of the solar cell provided in the embodiments of this application; Figure 6 yes Figure 3 A schematic diagram of the cross-sectional structure of the solar cells along line VI-VI; Figure 7 yes Figure 5 A schematic diagram of the cross-sectional structure of the solar cells along line VII-VII; Figure 8 This is another cross-sectional structural schematic diagram of the solar cell provided in the embodiments of this application; Figure 9 This is another cross-sectional structural schematic diagram of the solar cell provided in the embodiments of this application.

[0030] Explanation of key component symbols: Photovoltaic system 1000, battery module 200, solar cell 100, silicon substrate 10, first surface 11, second surface 12, first dielectric layer 20, first doped layer 30, first doped region 31, second doped region 32, third doped region 33, first gate electrode 40, first inner expansion layer 50, second dielectric layer 60, second doped layer 70, fourth doped region 71, fifth doped region 72, sixth doped region 73, second gate electrode 80, back passivation film layer 90, second inner expansion layer 110. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application. Furthermore, it should be understood that the specific embodiments described herein are merely for explaining this application and are not intended to limit this application.

[0032] In the description of this application, it should be understood that the terms "length", "width", "upper", "lower", "lateral", "longitudinal", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0033] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified.

[0034] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0035] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0036] The following disclosure provides numerous different embodiments or examples for implementing various structures of this application. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the scope of this application. Furthermore, reference numerals and / or letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. In addition, various specific examples of processes and materials are provided in this application, but those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0037] Please see Figures 1-2 The photovoltaic system 1000 in this application embodiment may include the battery module 200 in this application embodiment, and the battery module 200 in this application embodiment may include a plurality of solar cells 100 in this application embodiment.

[0038] In embodiments of this application, multiple solar cells 100 in the battery module 200 can be connected in series to form multiple battery strings. These battery strings can be connected in series, in parallel, or in a series-parallel combination to achieve current collection and output. For example, the connection between individual cells can be achieved by welding electrical connectors, or the connection between battery strings can be achieved by busbars. In some embodiments, the battery strings can form a cell array, and then be encapsulated together by a front panel, a front encapsulating film, a rear encapsulating film, and a back panel to form the battery module 200.

[0039] Please see Figures 3-7 The solar cell 100 in this embodiment may include a silicon substrate 10, a first dielectric layer 20, a first doped layer 30, and a first gate electrode 40.

[0040] The silicon substrate 10 has a first surface 11 and a second surface 12 opposite to each other. A first dielectric layer 20 is stacked on the first surface 11. A first doped layer 30 is stacked on the first dielectric layer 20. The first doped layer 30 is doped with a first doping element. The first doped layer 30 includes at least one first doped region 31 and a plurality of second doped regions 32 that are conductive to the first doped region 31. The plurality of second doped regions 32 are spaced apart from each other. The doping concentration of the first doping element in the first doped region 31 is greater than the doping concentration of the first doping element in the second doped region 32. A first gate electrode 40 is disposed on the first doped layer 30 and electrically connected to the first doped layer 30.

[0041] In the region of the first doped layer 30 covered by the first gate electrode 40 (i.e., the electrode region), the area of ​​the first doped region 31 is at least 35%, for example, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 100%, or other values ​​greater than 30%. In the region of the first doped layer 30 not covered by the first gate electrode 40 (i.e., the non-electrode region), the area ratio of the first doped region 31 is 5%-85%, for example, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, or other values ​​between 5% and 85%.

[0042] It should be noted that "the area percentage of the first doped region 31 in the region covered by the first gate electrode 40 of the first doped layer 30" refers to the area percentage of the first doped region 31 in the orthogonal projection region formed by the first gate electrode 40 on the first doped layer 30 in the thickness direction. Similarly, "the area percentage of the first doped region 31 in the region of the first doped layer 30 not covered by the first gate electrode 40" refers to the area percentage of the first doped region 31 in the region of the first doped layer 30 not covered by the first gate electrode 40. It is easy to understand that in this document, the area of ​​the doped region refers to the area of ​​the orthogonal projection region formed on the silicon substrate 10 in the thickness direction. If similar descriptions exist below, please refer to this document for clarification.

[0043] In the solar cell 100, cell module 200, and photovoltaic system 1000 of this application embodiment, a first dielectric layer 20 is stacked on a first surface 11. A first doped layer 30 is stacked on the first dielectric layer 20. The first doped layer 30 is doped with a first doping element and includes at least one first doped region 31 and a plurality of second doped regions 32 that are conductive to the first doped region 31. The plurality of second doped regions 32 are spaced apart from each other, and the doping concentration of the first doping element in the first doped region 31 is greater than the doping concentration of the first doping element in the second doped region 32. A first grid electrode 40 is disposed on the first doped layer 30 and electrically connected to the first doped layer 30. In the area of ​​the first doped layer 30 covered by the first grid electrode 40, the area ratio of the first doped region 31 is at least 35%, and in the area of ​​the first doped layer 30 not covered by the first grid electrode 40, the area ratio of the first doped region 31 is 5%-85%. Thus, by having a first doped region 31 with a high doping concentration and a second doped region 32 with a low doping concentration in the first doped layer 30, and by precisely controlling the area ratio of the first doped region 31 in the region covered by the first gate electrode 40 to be at least 35%, and controlling the area ratio of the first doped region 31 in the remaining regions to be between 5% and 85%, it is possible to reduce the interface recombination centers and Auger recombination losses in the silicon substrate 10 while ensuring the carrier collection efficiency. That is, by performing such precise and specific optimization design on the area ratio of the high doping concentration first doped region 31 in the electrode region and the non-electrode region, a balance optimization of low recombination centers and low Auger recombination with carrier collection efficiency can be achieved. This effectively reduces recombination centers and Auger recombination while ensuring high carrier collection efficiency, thereby optimizing the overall performance of the solar cell 100.

[0044] Specifically, in the area covered by the first gate electrode 40, by ensuring that the area ratio of the first doped region 31 (high-concentration doped region) is at least 35%, a low-resistance ohmic contact can be formed between the first gate electrode 40 and the first doped layer 30. This avoids an excessively high contact resistance due to an excessively high proportion of low doping concentration in the area covered by the first gate electrode 40, thereby ensuring the efficiency of charge carriers. In the area not covered by the first gate electrode 40, i.e., the main area for photogenerated charge carriers, controlling the area ratio of the first doped region 31 (high-concentration doped region) to 5%-85% can prevent the proportion of the first doped region 31 in the non-electrode area from being too small and the proportion of the second doped region 32 from being too large, which would lead to excessively high lateral transport resistance and thus low charge carrier collection efficiency. At the same time, it can also prevent the proportion of the first doped region 31 in the non-electrode area from being too large, thereby reducing the damage of doping elements to the interface between the first dielectric layer 20 and the silicon substrate 10 below the non-electrode area, effectively reducing recombination centers and Auger recombination.

[0045] In summary, the overall technical concept of this embodiment lies in the refined design of the structure of the first doped layer 30. In the electrode coverage area where low contact resistance is required, a first doped region 31 with high concentration doping is used and its area ratio is ensured. In the non-electrode coverage area, a second doped region 32 with partial low concentration doping is used and the area ratio of the first doped region 31 with high concentration doping in the non-electrode coverage area is controlled. At the same time, the electrical conduction between different doped regions is ensured. This regional and differentiated doping structure enables the solar cell 100 to effectively ensure the collection efficiency of charge carriers while reducing the interface recombination centers, thereby improving the overall performance of the cell.

[0046] Furthermore, in the embodiments of this application, due to the provision of a second doped region 32 with a low doping concentration, the parasitic absorption of light by the first doped layer 30 can be reduced, thereby improving the utilization rate of light.

[0047] Specifically, in the embodiments of this application, the silicon substrate 10 can be an n-type silicon substrate or a p-type silicon substrate. That is, the conductivity type of the silicon substrate 10 can be p-type or n-type, and there is no specific limitation here. The first surface 11 and the second surface 12 are two opposite surfaces of the silicon substrate 10 in the thickness direction.

[0048] The first dielectric layer 20 may be a tunneling layer, such as a tunneling silicon oxide layer. Of course, in some embodiments, the first dielectric layer 20 may also be a silicon nitride, silicon oxynitride, silicon carbide, intrinsic amorphous silicon, etc., and there is no specific limitation here.

[0049] In some embodiments, the area ratio of the first doped region 31 in the region of the first doped layer 30 covered by the first gate electrode 40 and the area ratio of the first doped region 31 in the region of the first doped layer 30 not covered by the first gate electrode 40 can both be measured using atomic force microscopy. The doping concentration of the dopant element in the first doped region 31 and the second doped region 32 can be measured using dynamic secondary ion mass spectrometry (DSIMS). In the following text, if the technical content related to area ratio and doping concentration is involved, the specific testing methods can also be understood by referring to this document.

[0050] In the embodiments of this application, the solar cell 100 may be a bifacial cell (e.g., a Topcon cell) or a back-contact cell.

[0051] like Figure 3 , Figure 4 as well as Figure 6 As shown, in some embodiments, when the solar cell 100 is a bifacial cell, the solar cell 100 further includes a second dielectric layer 60, a second doped layer 70, and a second grid electrode 80. The second dielectric layer 60 is stacked on the second surface 12, and the second doped layer 70 is stacked on the second dielectric layer 60. The second doped layer 70 is doped with a second dopant element, and the conductivity type of the second doped layer 70 is opposite to that of the first doped layer 30. The second grid electrode 80 is in electrical contact with the second doped layer 70. In this case, one of the first surface 11 and the second surface 12 is the front side of the silicon substrate 10, and the other is the back side of the silicon substrate 10. The second dielectric layer 60 can also be a tunneling layer, such as a tunneling silicon oxide layer. Of course, in some embodiments, the second dielectric layer 60 can also be a film layer such as silicon nitride, silicon oxynitride, silicon carbide, intrinsic amorphous silicon, etc., and there is no specific limitation here.

[0052] In the case where the solar cell 100 is a bifacial cell, both the first doped layer 30 and the second doped layer 70 of the solar cell 100 may have a passivation film (not shown in the figure). The first grid electrode 40 is disposed on the first doped layer 30 and penetrates the passivation film on the first doped layer 30 to make electrical contact with the first doped layer 30. A second grid electrode 80 may be disposed on the second doped layer 70, and the second grid electrode 80 penetrates the passivation film covering the second doped layer 70 to make contact with the second doped layer 70.

[0053] Of course, it is understood that in some possible embodiments, when the solar cell 100 is a bifacial cell, the solar cell 100 may not have a second dielectric layer 60, and no specific limitation is made here.

[0054] like Figure 5 and Figure 7As shown, in some embodiments, when the solar cell 100 is a back-contact cell, the solar cell 100 also includes a second dielectric layer 60, a second doped layer 70, and a second gate electrode 80. The second dielectric layer 60 is also stacked on the first surface 11, which is the back side of the silicon substrate 10, and the second surface 12 is the front side of the silicon substrate 10. The second dielectric layer 60 can also be a tunneling layer, such as a tunneling silicon oxide layer. Of course, in some embodiments, the second dielectric layer 60 can also be a silicon nitride, silicon oxynitride, silicon carbide, intrinsic amorphous silicon, etc., and there is no specific limitation here. The second doped layer 70 is stacked on the second dielectric layer 60. There are several first doped layers 30 and several second doped layers 70. The several first doped layers 30 and several second doped layers 70 are alternately arranged on the first surface 11 along the first direction. The second doped layer 70 is doped with a second doping element, and the conductivity type of the second doped layer 70 is opposite to that of the first doped layer 30. The second gate electrode 80 is in electrical contact with the second doped layer 70. In this case, both the first doped layer 30 and the second doped layer 70 can extend along the second direction, and the first direction and the second direction intersect. For example, in some embodiments, the first direction and the second direction can be the lateral direction and the longitudinal direction of the solar cell 100, respectively.

[0055] like Figure 7 As shown, when the solar cell 100 is a back contact cell, a back passivation film layer 90 may be provided on the outermost side of the first surface 11. The first grid line electrode 40 passes through the back passivation film layer 90 and is electrically connected to the first doped layer 30. The second grid line electrode 80 passes through the back passivation film layer 90 and is electrically connected to the second doped layer 70.

[0056] Of course, in some embodiments, the solar cell 100 in this application may also be a stacked cell having bifacial cells or back contact cells as described above, such as a stacked cell formed by perovskite cells and Topcon cells, or a stacked cell formed by perovskite cells and back contact cells. In such cases, bifacial cells or back contact cells may be used as the bottom cells of the stacked cells.

[0057] like Figure 7 As shown, in some embodiments, when the solar cell 100 is a back-contact cell, the first doped layer 30 and the second doped layer 70 can be isolated by trenches.

[0058] Of course, it is understood that in some possible embodiments, the first doped layer 30 and the second doped layer 70 can also be isolated in other ways, such as by providing an intrinsic polycrystalline silicon layer, an intrinsic amorphous silicon layer, or a polycrystalline silicon layer with extremely low doping concentration, etc., and no specific limitation is made here. In addition, in some possible embodiments, the first doped layer 30 and the second doped layer 70 may be in contact in a local area of ​​the trench, thereby improving the hot spot resistance performance of the back contact battery.

[0059] Specifically, in the solar cell 100, one of the first doping element and the second doping element can be a Group 3 element (such as boron, gallium, etc.), and the other can be a Group 5 element (such as phosphorus, arsenic, antimony, etc.), without any specific restrictions. That is to say, regardless of whether it is a bifacial cell or a back-contact cell, one of the first doping layer 30 and the second doping layer 70 is a p-type doping layer, and the other is an n-type doping layer.

[0060] In some embodiments, the conductivity type of the first doped layer 30 is opposite to that of the silicon substrate 10. In such cases, the conductivity type of the second doped layer 70 is the same as that of the silicon substrate 10. Thus, by performing the specific optimization design described above on the first doped layer 30, which has a conductivity type opposite to that of the silicon substrate 10, the solar cell 100 can achieve better performance compared to optimizing the second doped layer 70, which has the same conductivity type as that of the silicon substrate 10.

[0061] In some embodiments, the first doping element in the first doped layer 30 is boron, and the first doped layer 30 is a p-type doped layer. Specifically, in the p-type doped layer, a higher boron doping concentration can cause greater damage to the first dielectric layer 20. Therefore, optimizing the design of the boron-doped first doped layer 30 by partitioning it can achieve better performance improvement.

[0062] It is easy to understand that, in this case, the silicon substrate 10 is an n-type silicon substrate, and the second doping element in the second doped layer 70 can be a Group 5 element such as phosphorus, arsenic, or antimony. In some embodiments, the second doping element is preferably phosphorus.

[0063] Please see Figure 3 and Figure 5 In some embodiments, there are multiple first doped regions 31, and the multiple first doped regions 31 are interconnected.

[0064] In this way, multiple highly doped first doped regions 31 are interconnected, which can ensure that in-plane charges can be efficiently transported and collected to the first gate electrode 40, thereby improving the collection efficiency of charge carriers.

[0065] Of course, it is understandable that in some possible embodiments, the plurality of first doped layers 30 may also be randomly spaced, and no specific limitation is made here.

[0066] In some embodiments, in the solar cell 100, the second doped region 32 in the first doped layer 30 can be arranged in a regular array or randomly. The outline shape of the second doped region 32 can be a regular shape or an irregular shape, such as a rectangle, circle, square, triangle, trapezoid, semicircle, ellipse, etc., and there is no specific limitation here.

[0067] In some embodiments, the size of the second doped region 32 in the first doped layer 30 can be 1 μm-600 μm, or other values ​​between 1 μm, 5 μm, 10 μm, 50 μm, 100 μm, 150 μm, 200 μm, 250 μm, 300 μm, 350 μm, 400 μm, 450 μm, 500 μm, 550 μm, 600 μm, or 1 μm-600 μm. The "size of the second doped region 32" refers to the length of the line connecting the two furthest points on the outline of the second doped layer 32.

[0068] Thus, by limiting the size of the second doped region 32 to a specific range of 1μm-600μm, the collection efficiency of carriers and recombination loss can be effectively balanced.

[0069] Furthermore, in some embodiments, the size of the second doped region 32 is preferably 5μm-300μm, and more preferably 20μm-160μm.

[0070] Please see Figures 3-7 In some embodiments, the area of ​​the first doped layer 30 covered by the first gate electrode 40 is the first doped region 31. That is to say, the area covered by the first gate electrode 40 does not contain the low-doped second doped region 32, but is composed entirely of the high-doped first doped region 31.

[0071] In this way, by setting the area covered by the first gate electrode 40 as the first doped region 31, the contact resistance between the first gate electrode 40 and the first doped layer 30 can be further reduced, and the carrier collection efficiency of the region can be optimized.

[0072] In some embodiments, in the region of the first doped layer 30 not covered by the first gate electrode 40, the area ratio of the first doped region 31 is preferably 25%-70%, such as 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, or other values ​​between 25% and 70%.

[0073] Thus, by further optimizing the area ratio of the first doped region 31 in the region of the first doped layer 30 not covered by the first gate electrode 40 to within the range of 25%-70%, a fine balance between carrier collection and surface recombination loss can be further achieved.

[0074] The inventors of this application have researched and verified that such further optimized design can ensure sufficient area for efficient collection of photogenerated carriers, while retaining sufficient low-doped regions to effectively reduce recombination centers and Auger recombination. This avoids the increase in recombination losses caused by recombination centers due to excessively large high-doped regions, and also avoids the decrease in carrier collection efficiency due to excessively small high-doped regions. This optimized configuration enables the solar cell 100 to achieve the best balance between carrier collection efficiency and surface recombination loss within the illuminated area.

[0075] In some embodiments, the doping concentration of the first dopant element in the first doped region 31 may be 1E19 / cm³. 3 -1E21 / cm 3 For example, 1E19 / cm 3 2E19 / cm 3 4E19 / cm 3 6E19 / cm 3 8E19 / cm 3 1E20 / cm 3 2E20 / cm 3 4E20 / cm 3 6E20 / cm 3 8E20 / cm 3 1E21 / cm 3 Or 1E19 / cm 3 -1E21 / cm 3 Other values ​​between these. The doping concentration of the first doped element in the second doped region 32 can be less than 1E18 / cm. 3 For example, 8E17 / cm 3 5E17 / cm 3 2E17 / cm 3 1E17 / cm 3 8E16 / cm 3 6E16 / cm 3 5E16 / cm 3 4E16 / cm 3 2E16 / cm 3 1E16 / cm 3 1E15 / cm 3 1E14 / cm 3 1E13 / cm 3 wait.

[0076] In this way, a region with a significant concentration gradient can be formed inside the first doped layer 30, and the doping concentration of the first doped region 31 can be set at 1E19 / cm³. 3 -1E21 / cm 3 Within this reasonable range, a low-resistance ohmic contact can be formed with the first gate electrode 40, efficiently collecting charge carriers, while avoiding excessive parasitic absorption due to excessive doping concentration. The doping concentration of the second doped region 32 is set to be less than 1E18 / cm. 3 This can significantly reduce recombination centers and Auger recombination in the bulk region. This synergistic configuration of high and low doping regions, combined with the area ratio control of the first doping region 31 in different regions, enables the solar cell 100 to minimize carrier recombination loss while ensuring good electrical contact, thereby optimizing carrier collection efficiency and improving the overall performance of the cell.

[0077] Furthermore, in such an embodiment, the doping concentration of the first dopant element in the second doped region 32 is preferably less than 1E17 / cm³. 3 For example, 8E16 / cm 3 6E16 / cm 3 5E16 / cm 3 4E16 / cm 3 2E16 / cm 3 1E16 / cm 3 1E15 / cm 3 1E14 / cm 3 1E13 / cm 3 Etc. Specifically, the inventors of this application have discovered that the doping concentration of the second doped region 32 with a low doping concentration can be further set to be less than 1E17 / cm. 3 This can create a region with a larger concentration difference with the first doped region 31, thereby further reducing carrier recombination loss.

[0078] In some embodiments, the doping concentration of the first dopant element in the second doped region 32 may be greater than or equal to 1E13 / cm³. 3 And less than 1E17 / cm 3 For example, 8E16 / cm 3 6E16 / cm 3 5E16 / cm 3 4E16 / cm 3 2E16 / cm 3 1E16 / cm 3 1E15 / cm 3 1E14 / cm 3 1E13 / cm 3Thus, the lower limit of the doping concentration of the second doped region 32 is set at 1E13 / cm. 3 This can reduce carrier recombination losses and avoid the second doping region 32 having too low a doping concentration, which would severely affect the lateral transport of carriers.

[0079] Please see Figure 6 and Figure 7 In some embodiments, the first doped layer 30 may further include a third doped region 33, which is located between the second doped region 32 and the first doped region 31, and the second doped region 32 is connected to the first doped region 31 through the third doped region 33. The doping concentration of the first doped element in the third doped region 33 is greater than that of the first doped element in the second doped region 32 but less than that of the first doped element in the first doped region 31.

[0080] It is easy to understand that the third doped region 33 refers to a doped region located between the second doped region 32 and the first doped region 31 in the first doped layer 30. The main function of this region is to serve as a doping concentration transition layer to smooth the doping concentration gradient between the first doped region 31 and the second doped region 32.

[0081] Thus, by setting a third doped region 33 between the second doped region 32 and the first doped region 31, and the doping concentration of the first doped element in the third doped region 33 being between the second doped region 32 and the first doped region 31, a smooth doping concentration gradient is formed. This gradual concentration distribution makes the electric field change experienced by the charge carriers during the transport process from the second doped region 32 to the first doped region 31 more gradual, effectively reducing the carrier recombination rate at the interface. The charge carriers can transition more smoothly from the low concentration region to the high concentration region, reducing the loss in the transport path, thereby improving the carrier collection efficiency.

[0082] In some embodiments, the doping concentration of the first dopant element in the third doping region 33 gradually decreases in the direction away from the first doping region 31. That is, the doping concentration distribution inside the third doping region 33 is not uniform, but exhibits a gradient change. The doping concentration is relatively high on the side closer to the first doping region 31, and gradually decreases as it moves further away from the first doping region 31, reaching its lowest point at the position where it contacts the second doping region 32.

[0083] Thus, by setting the doping concentration of the first doping element in the third doping region 33 to gradually decrease in the direction away from the first doping region 31, the electric field distribution in the third doping region 33 can be optimized, thereby improving the collection efficiency of minority carriers and reducing recombination losses.

[0084] In some embodiments, the width L1 of the third doped region 33 can be 0.1 μm-8 μm, for example, 0.1 μm, 0.5 μm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, or other values ​​between 0.1 μm and 8 μm. "The width of the third doped region 33" can be understood as the shortest distance between the contact interface between the third doped region 33 and the first doped region 31 and the contact interface between the third doped region and the second doped region 32.

[0085] Thus, limiting the width of the third doped region 33 to a specific range of 0.1 μm-8 μm effectively optimizes the carrier transport path within the first doped layer 30. This allows photogenerated carriers to experience a smooth and efficient electric field guidance as they move from the low-doped second doped region 32 to the high-doped first doped region 31, significantly reducing recombination losses during transport. Simultaneously, the appropriate width of the third doped region 33 avoids the increased risk of surface recombination due to an excessively wide region, and also avoids the decreased carrier collection efficiency caused by an excessively narrow region.

[0086] Specifically, if the third doped region 33 is too narrow, the concentration gradient it provides may be insufficient to effectively guide carriers, causing carriers to encounter significant barriers or recombination losses during transport from the second doped region 32 to the first doped region 31, thus reducing collection efficiency. Conversely, if the third doped region 33 is too wide, although it can provide a gentler concentration gradient, it occupies more surface area, and due to its relatively high doping concentration, it may increase the risk of surface recombination, especially in areas not covered by the grid electrodes, thus offsetting its advantages in carrier transport. Therefore, controlling the width of the third doped region 33 within a specific range of 0.1 μm to 8 μm ensures a better balance between carrier transport efficiency and surface recombination loss, enabling efficient collection of photogenerated carriers while minimizing recombination losses, thereby improving the overall performance of the solar cell 100.

[0087] Please see Figure 6 and Figure 7 At the location corresponding to the first doped region 31, a first inner expansion layer 50 is formed on the silicon substrate 10. The first inner expansion layer 50 is in contact with the first dielectric layer 20. The doping concentration of the first doped element in the first inner expansion layer 50 is less than 20% of the doping concentration of the first doped element in the first doped region 31 and is greater than or equal to 10 ppm.

[0088] Thus, by setting the doping concentration of the first inner layer 50 within this reasonable range, it is possible to effectively avoid excessive recombination centers and Auger recombination in the bulk region due to excessively high doping concentration of the first inner layer 50. Setting the lower limit of the doping concentration in the first inner layer 50 to 10 ppm can effectively enhance the built-in electric field and reduce carrier recombination. In other words, through such optimized design, the relationship between bulk recombination centers, Auger recombination, and carrier collection efficiency can be balanced, maximizing current collection efficiency while keeping recombination losses within an acceptable range.

[0089] Please see Figures 3-7 In some embodiments, the second doped layer 70 may include at least one fourth doped region 71 and a plurality of fifth doped regions 72 connected to the fourth doped region 71, wherein the doping concentration of the second doped element in the fourth doped region 71 is greater than the doping concentration of the second doped element in the fifth doped region 72. The solar cell 100 also includes a second grid electrode 80 disposed on and electrically connected to the second doped layer 70.

[0090] In the region where the second doped layer 70 is covered by the second gate electrode 80, the area of ​​the fourth doped region 71 is at least 35%, such as 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 100%, or other values ​​greater than 30%. In the region of the second doped layer 70 not covered by the second gate electrode 80, the area ratio of the fourth doped region 71 is 5%-85%, for example, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, or other values ​​between 5% and 85%.

[0091] It should be noted that "the area percentage of the fourth doped region 71 in the region of the second doped layer 70 covered by the second gate electrode 80" refers to the proportion of the fourth doped region 71 in the orthogonal projection region formed by the second gate electrode 80 on the second doped layer 70 in the thickness direction. Similarly, "the area percentage of the fourth doped region 71 in the region of the second doped layer 70 not covered by the second gate electrode 80" refers to the proportion of the fourth doped region 71 in the region of the second doped layer 70 not covered by the second gate electrode 80.

[0092] Thus, by having a fourth doped region 71 with a high doping concentration and a fifth doped region 72 with a low doping concentration in the second doped layer 70, and precisely controlling the area ratio of the fourth doped region 71 in the region covered by the second gate electrode 80 to be at least 35%, and controlling the area ratio of the fourth doped region 71 in the remaining regions to be between 5% and 85%, it is possible to reduce the interface recombination centers and Auger recombination losses in the silicon substrate 10 while ensuring the carrier collection efficiency. That is, by performing such precise and specific optimization design on the area ratio of the high-doped fourth doped region 71 in the electrode region and non-electrode region, a balance optimization between low recombination centers and low Auger recombination and carrier collection efficiency can be achieved. This effectively reduces recombination centers and Auger recombination while ensuring high carrier collection efficiency, thereby optimizing the overall performance of the solar cell 100.

[0093] Specifically, in the area covered by the second gate electrode 80, by ensuring that the area ratio of the fourth doped region 71 (high-concentration doped region) is at least 35%, a low-resistance ohmic contact can be formed between the second gate electrode 80 and the second doped layer 70. This avoids an excessively high contact resistance due to an excessively high proportion of low doping concentration in the area covered by the second gate electrode 80, thus ensuring carrier efficiency. In the area not covered by the second gate electrode 80, which is the main area for photogenerated carriers, controlling the area ratio of the fourth doped region 71 (high-concentration doped region) between 5% and 85% can prevent the proportion of the fourth doped region 71 in the non-electrode area from being too small and the proportion of the fifth doped region 72 from being too large, which would lead to excessively high lateral transport resistance and thus low carrier collection efficiency. At the same time, it can also prevent the proportion of the fourth doped region 71 in the non-electrode area from being too large, thereby reducing the damage of dopant elements to the interface between the second dielectric layer 60 and the silicon substrate 10 below the non-electrode area, effectively reducing recombination centers and Auger recombination.

[0094] Furthermore, in the embodiments of this application, due to the provision of a fifth doped region 72 with a low doping concentration, the parasitic absorption of light by the second doped layer 70 can be reduced, thereby improving the utilization rate of light.

[0095] In some embodiments, the silicon substrate 10 may be an n-type silicon substrate, the first doped layer 30 may be a p-type doped layer, the first doping element may be a group 3 element such as boron, the second doped layer 70 may be an n-type doped layer, and the second doping element may be a group 5 element such as phosphorus.

[0096] Of course, in some possible embodiments, the second doped layer 70 may not be configured with such a concentration difference, but rather it may be configured as a doped layer with a substantially uniform concentration (e.g., substantially the same as the doping concentration of the fourth doped region 71). No specific limitations are imposed here. For example, as... Figure 8As shown, in some possible embodiments, when the solar cell 100 is a bifacial cell, the second doped layer 70 can be a doped layer with a substantially uniform doping concentration and stacked on the second surface 12. For example, as... Figure 9 As shown, in some possible embodiments, when the solar cell 100 is a back-contact cell, the second doped layer 70 may be a doped layer with a substantially uniform doping concentration and stacked on the first surface 11.

[0097] Please see Figure 4 and Figure 5 In some embodiments, there are multiple fourth doped regions 71, and the multiple fourth doped regions 71 are interconnected.

[0098] In this way, multiple highly doped fourth doped regions 71 are interconnected, which can ensure that in-plane charges can be efficiently transported and collected to the second gate electrode 80, thereby improving the collection efficiency of charge carriers.

[0099] Of course, it is understandable that in some possible embodiments, the multiple fourth doped regions 71 may also be randomly spaced, and no specific limitation is made here.

[0100] In some embodiments, in the solar cell 100, the fifth doped region 72 in the second doped layer 70 can be arranged in a regular array or randomly. The outline shape of the fifth doped region 72 can be a regular shape or an irregular shape, such as a rectangle, circle, square, triangle, trapezoid, semicircle, ellipse, etc., and there is no specific limitation here.

[0101] In some embodiments, the size of the fifth doped region 72 in the second doped layer 70 may be 1μm-600μm, 1μm, 5μm, 10μm, 50μm, 100μm, 150μm, 200μm, 250μm, 300μm, 350μm, 400μm, 450μm, 500μm, 550μm, 600μm, or other values ​​between 1μm and 600μm.

[0102] The “size of the fifth doped region 72” refers to the length of the line connecting the two furthest points on the outline of the fifth doped region 72.

[0103] Thus, by limiting the size of the fifth doped region 72 to a specific range of 1μm-600μm, the collection efficiency of carriers and recombination loss can be effectively balanced.

[0104] Please see Figure 4 and Figure 5In some embodiments, the area of ​​the second doped layer 70 covered by the second gate electrode 80 is entirely the second doped layer 70. That is to say, the area covered by the second gate electrode 80 does not contain the low-doped fifth doped region 72, but is entirely composed of the high-doped fourth doped region 71.

[0105] Thus, by setting the area covered by the second gate electrode 80 as the fourth doped region 71, the contact resistance between the second gate electrode 80 and the second doped layer 70 can be further reduced, and the carrier collection efficiency of this region can be optimized.

[0106] In some embodiments, in the region of the second doped layer 70 not covered by the second gate electrode 80, the area ratio of the fourth doped region 71 is preferably 25%-70%, such as 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, or other values ​​between 25% and 70%.

[0107] Thus, by further optimizing the area ratio of the fourth doped region 71 in the region of the second doped layer 70 not covered by the second gate electrode 80 to within the range of 25%-70%, a finer balance between carrier collection and surface recombination loss can be achieved. The inventors of this application have researched and extended their findings, discovering that such further optimization ensures sufficient area for efficient collection of photogenerated carriers while retaining enough low-doped regions to effectively reduce recombination centers and Auger recombination. This avoids increased recombination losses due to excessively large high-doped regions and decreased carrier collection efficiency due to excessively small high-doped regions. This optimized configuration allows the solar cell 100 to achieve the best balance between carrier collection efficiency and surface recombination loss within the illuminated area.

[0108] In some possible embodiments, the doping concentration of the second dopant element in the fourth doped region 71 may be 1E19 / cm³. 3 -1E21 / cm 3 For example, 1E19 / cm 3 2E19 / cm 3 4E19 / cm 3 6E19 / cm 3 8E19 / cm 3 1E20 / cm 3 2E20 / cm 3 4E20 / cm 3 6E20 / cm 3 8E20 / cm 3 1E21 / cm 3 Or 1E19 / cm 3 -1E21 / cm3 Other values ​​between these. The doping concentration of the second doped element in the fifth doped region 72 can be less than 1E18 / cm. 3 For example, 8E17 / cm 3 5E17 / cm 3 2E17 / cm 3 1E17 / cm 3 8E16 / cm 3 6E16 / cm 3 5E16 / cm 3 4E16 / cm 3 2E16 / cm 3 1E16 / cm 3 1E15 / cm 3 1E14 / cm 3 1E13 / cm 3 wait.

[0109] In this way, a region with a significant concentration gradient can be formed inside the second doped layer 70, and the doping concentration of the fourth doped region 71 can be set at 1E19 / cm³. 3 -1E21 / cm 3 Within this reasonable range, a low-resistance ohmic contact can be formed with the second gate electrode 80, efficiently collecting charge carriers, while avoiding excessive parasitic absorption due to excessive doping concentration. The doping concentration of the fifth doped region 72 is set to be less than 1E18 / cm. 3 This can significantly reduce recombination centers and Auger recombination in the bulk region. This synergistic configuration of high and low doping regions, combined with the area ratio control of the fourth doping region 71 in different regions, enables the solar cell 100 to minimize carrier recombination loss while ensuring good electrical contact, thereby optimizing carrier collection efficiency and improving the overall performance of the cell.

[0110] Furthermore, in such an embodiment, the doping concentration of the second dopant element in the fifth doped region 72 is preferably less than 1E17 / cm³. 3 For example, 8E16 / cm 3 6E16 / cm 3 5E16 / cm 3 4E16 / cm 3 2E16 / cm 3 1E16 / cm 3 1E15 / cm 3 1E14 / cm 3 1E13 / cm 3 Etc. Specifically, the inventors of this application have discovered that the doping concentration of the low-doped fifth doped region 72 can be further set to less than 1E17 / cm.3 This can create a region with a larger concentration difference with the fourth doped region 71, thereby further reducing carrier recombination loss.

[0111] In some embodiments, the doping concentration of the second dopant element in the fifth doped region 72 may be greater than or equal to 1E13 / cm³. 3 And less than 1E17 / cm 3 For example, 8E16 / cm 3 6E16 / cm 3 5E16 / cm 3 4E16 / cm 3 2E16 / cm 3 1E16 / cm 3 1E15 / cm 3 1E14 / cm 3 1E13 / cm 3 Thus, the lower limit of the doping concentration in the fifth doped region 72 is set at 1E13 / cm². 3 This can reduce carrier recombination losses and avoid the problem of excessively low doping concentration in the fifth doping region 72, which would severely affect the lateral transport of carriers.

[0112] Please see Figure 6 and Figure 7 In some embodiments, the second doped layer 70 may further include a sixth doped region 73, which is located between the fifth doped region 72 and the fourth doped region 71, and the fifth doped region 72 is connected to the fourth doped region 71 through the sixth doped region 73. The doping concentration of the second doped element in the sixth doping region 73 is greater than that of the second doped element in the fifth doping region 72 and less than that of the second doped element in the fourth doping region 71.

[0113] It is easy to understand that the sixth doped region 73 refers to a doped region located between the fifth doped region 72 and the fourth doped region 71 in the second doped layer 70. The main function of this region is to serve as a doping concentration transition layer to smooth the doping concentration gradient between the fourth doped region 71 and the fifth doped region 72.

[0114] Thus, by setting a sixth doping region 73 between the fifth doping region 72 and the fourth doping region 71, and the doping concentration of the second dopant element in the sixth doping region 73 being between that of the fifth doping region 72 and the fourth doping region 71, a smooth doping concentration gradient is formed. This gradual concentration distribution makes the electric field change experienced by the charge carriers during the transport process from the fifth doping region 72 to the fourth doping region 71 more gradual, effectively reducing the carrier recombination rate at the interface. The charge carriers can transition more smoothly from the low concentration region to the high concentration region, reducing the loss in the transport path, thereby improving the carrier collection efficiency.

[0115] In some embodiments, the doping concentration of the second dopant element in the sixth doping region 73 gradually decreases in the direction away from the fourth doping region 71. That is, the doping concentration distribution inside the sixth doping region 73 is not uniform, but exhibits a gradient change. The doping concentration is relatively high on the side closer to the fourth doping region 71, and gradually decreases as the distance from the fourth doping region 71 increases, reaching its lowest point at the position in contact with the fifth doping region 72.

[0116] Thus, by setting the doping concentration of the second doping element in the sixth doping region 73 to gradually decrease in the direction away from the fourth doping region 71, the electric field distribution in the sixth doping region 73 can be optimized, thereby improving the collection efficiency of minority carriers and reducing recombination losses.

[0117] In some embodiments, the width L2 of the sixth doped region 73 can be 0.1 μm-8 μm, for example, 0.1 μm, 0.5 μm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, or other values ​​between 0.1 μm and 8 μm. "The width of the sixth doped region 73" can be understood as the shortest distance between the contact interface between the sixth doped region 73 and the fourth doped region 71 and the contact interface between the third doped region and the fifth doped region 72.

[0118] Thus, limiting the width of the sixth doped region 73 to a specific range of 0.1 μm-8 μm effectively optimizes the carrier transport path within the second doped layer 70. This allows photogenerated carriers to experience a smooth and efficient electric field guidance as they move from the low-doped fifth doped region 72 to the high-doped fourth doped region 71, significantly reducing recombination losses during transport. Simultaneously, the appropriate width of the sixth doped region 73 avoids the increased risk of surface recombination due to an excessively wide region, and also avoids the decreased carrier collection efficiency caused by an excessively narrow region.

[0119] Specifically, if the sixth doped region 73 is too narrow, the concentration gradient it provides may be insufficient to effectively guide carriers, causing them to encounter significant barriers or recombination losses during transport from the fifth doped region 72 to the fourth doped region 71, thus reducing collection efficiency. Conversely, if the sixth doped region 73 is too wide, although it can provide a gentler concentration gradient, it occupies more surface area, and due to its relatively high doping concentration, it may increase the risk of surface recombination, especially in areas not covered by the grid electrodes, thus offsetting its advantages in carrier transport. Therefore, controlling the width L2 of the sixth doped region 73 within a specific range of 0.1 μm to 8 μm ensures a better balance between carrier transport efficiency and surface recombination loss, enabling efficient collection of photogenerated carriers while minimizing recombination losses, thereby improving the overall performance of the solar cell 100.

[0120] Please see Figure 6 and Figure 7 At the location corresponding to the fourth doping region 71, a second inner expansion layer 110 is formed on the silicon substrate 10. The second inner expansion layer 110 is in contact with the second dielectric layer 60. The doping concentration of the second doping element in the second inner expansion layer 110 is less than 20% of the doping concentration of the second doping element in the fourth doping region 71 and is greater than or equal to 10 ppm.

[0121] Thus, by setting the doping concentration of the second inner layer 110 within this reasonable range, it is possible to effectively avoid excessive recombination centers and Auger recombination in the bulk region due to excessively high doping concentration of the second inner layer 110. Setting the lower limit of the doping concentration in the second inner layer 110 to 10 ppm can effectively enhance the built-in electric field and reduce carrier recombination. In other words, through such optimized design, the relationship between bulk recombination centers, Auger recombination, and carrier collection efficiency can be balanced, maximizing current collection efficiency while keeping recombination losses within an acceptable range.

[0122] In the description of this specification, the use of terms such as "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples," etc., refers to specific features, structures, materials, or characteristics described in connection with the embodiments or examples, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiments or examples. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0123] Furthermore, the above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A solar cell, characterized in that, include: A silicon substrate having opposing first and second surfaces; A first dielectric layer is stacked on the first surface; A first doped layer is stacked on the first dielectric layer, the first doped layer being doped with a first doping element, the first doped layer including at least one first doped region and a plurality of second doped regions connected to the first doped region, the plurality of second doped regions being spaced apart from each other, and the doping concentration of the first doping element in the first doped region being greater than the doping concentration of the first doping element in the second doped region; and The first gate electrode is disposed on the first doped layer and electrically connected to the first doped layer; Wherein, in the region where the first doped layer is covered by the first gate electrode, the area of ​​the first doped region accounts for at least 35%, and in the region where the first doped layer is not covered by the first gate electrode, the area of ​​the first doped region accounts for 5%-85%.

2. The solar cell according to claim 1, characterized in that, The area of ​​the first doped layer covered by the first gate electrode is the first doped region.

3. The solar cell according to claim 1, characterized in that, In the region where the first doped layer is not covered by the first gate electrode, the area of ​​the first doped region accounts for 25%-70%.

4. The solar cell according to claim 1, characterized in that, the first doped element of the first doped region has a doping concentration of 1E19 / cm 3 -1E21 / cm 3 the first doped element of the second doped region has a doping concentration of less than 1E18 / cm 3 .

5. The solar cell according to claim 4, characterized in that, The doping concentration of the first dopant element in the second doped region is less than 1E17 / cm. 3 .

6. The solar cell according to claim 1, characterized in that, The first doped layer further includes a third doped region, which is located between the second doped region and the first doped region, and the second doped region is connected to the first doped region through the third doped region; Wherein, the doping concentration of the first doped element in the third doped region is greater than the doping concentration of the first doped element in the second doped region and less than the doping concentration of the first doped element in the first doped region.

7. The solar cell according to claim 6, characterized in that, In the direction away from the first doped region, the doping concentration of the first doped element in the third doped region gradually decreases.

8. The solar cell according to claim 6, characterized in that, The width of the third doped region is 0.1 μm-8 μm.

9. The solar cell according to claim 1, characterized in that, There are multiple first doped regions, and these multiple first doped regions are interconnected.

10. The solar cell according to claim 1, characterized in that, The size of the second doped region is 1μm-600μm.

11. The solar cell according to claim 1, characterized in that, The conductivity type of the first doped layer is opposite to that of the silicon substrate.

12. The solar cell according to claim 1, characterized in that, The first doping element is boron.

13. The solar cell according to claim 1, characterized in that, At the location corresponding to the first doped region, a first inner expansion layer is formed on the silicon substrate. The first inner expansion layer is in contact with the first dielectric layer. The doping concentration of the first doping element in the first inner expansion layer is less than 20% of the doping concentration of the first doping element in the first doped region and is greater than or equal to 10 ppm.

14. The solar cell according to any one of claims 1-13, characterized in that, The solar cell further includes a second dielectric layer and a second doped layer. The second dielectric layer is stacked on the second surface, and the second doped layer is stacked on the second dielectric layer. The second doped layer is doped with a second doping element, and the conductivity type of the second doped layer is opposite to that of the first doped layer. The solar cell further includes a second dielectric layer and a second doped layer. The second dielectric layer is also stacked on the first surface, and the second doped layer is stacked on the second dielectric layer. There are multiple first doped layers and multiple second doped layers. The multiple first doped layers and multiple second doped layers are alternately arranged on the first surface along a first direction. The second doped layer is doped with a second doping element, and the conductivity type of the second doped layer is opposite to that of the first doped layer.

15. The solar cell according to claim 14, characterized in that, The conductivity type of the first doped layer is opposite to that of the silicon substrate, and the conductivity type of the second doped layer is the same as that of the silicon substrate.

16. The solar cell according to claim 14, characterized in that, The second doped layer includes at least one fourth doped region and a plurality of fifth doped regions connected to the fourth doped region, wherein the doping concentration of the second doped element in the fourth doped region is greater than the doping concentration of the second doped element in the fifth doped region. The solar cell also includes: The second gate electrode is disposed on the second doped layer and electrically connected to the second doped layer; Specifically, in the region where the second doped layer is covered by the second gate electrode, the area of ​​the fourth doped region accounts for at least 35%, and in the region where the second doped layer is not covered by the second gate electrode, the area of ​​the fourth doped region accounts for 5%-85%.

17. The solar cell according to claim 16, characterized in that, The area of ​​the second doped layer covered by the second gate electrode is the fourth doped region.

18. The solar cell according to claim 16, characterized in that, In the region where the second doped layer is not covered by the second gate electrode, the area of ​​the fourth doped region accounts for 25%-70%.

19. The solar cell according to claim 16, characterized in that, The second doped layer further includes a sixth doped region, which is located between the fifth doped region and the fourth doped region, and the fifth doped region is connected to the fourth doped region through the sixth doped region; The doping concentration of the second doped element in the sixth doped region is greater than that in the fifth doped region but less than that in the fourth doped region.

20. A battery assembly, characterized in that, Includes the solar cells described in any one of claims 1-19.

21. A photovoltaic system, characterized in that, Includes the battery assembly as described in claim 20.

Images