Solar cell and method of manufacturing the same, stacked cell, and photovoltaic module

Abstract

The application relates to a solar cell, a manufacturing method thereof, a laminated cell and a photovoltaic module. The solar cell comprises a substrate with oppositely arranged first and second surfaces; a first doped layer on one side of the first surface; a first sub-diffusion layer on one side of the first doped layer away from the substrate; and a second sub-diffusion layer on one side of the first sub-diffusion layer away from the substrate; wherein the first doped layer, the first sub-diffusion layer and the second sub-diffusion layer all have a first doped element, and the doping concentration of the first doped element in the first sub-diffusion layer is less than that in the second sub-diffusion layer. The application can improve the photoelectric conversion efficiency of the solar cell.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of solar cell manufacturing, and in particular to a solar cell, a manufacturing method thereof, a stacked cell and a photovoltaic module. BACKGROUND

[0002] Solar energy, as a new energy, has various advantages such as inexhaustibility, cleanness and environmental protection compared with traditional fossil fuels. At present, a main way of solar energy utilization is to convert received light energy into electric energy output through a solar cell module, which can be a large-area cell module formed by packaging and arranging in a square matrix after series connection of a plurality of solar cells (or photovoltaic cells, or photovoltaic modules). Among them, the solar cell absorbs light energy, and accumulation of hetero-charges occurs at both ends of the cell, that is, a "photovoltaic effect" is generated. Under the action of the photovoltaic effect, an electromotive force is generated at both ends of the solar cell, so as to convert light energy into electric energy.

[0003] However, the photoelectric conversion efficiency of the solar cell in the prior art needs to be further improved. SUMMARY

[0004] Therefore, it is necessary to provide a solar cell, a manufacturing method thereof, a stacked cell and a photovoltaic module for solving the problem of how to improve the photoelectric conversion efficiency of the solar cell.

[0005] In a first aspect, the present application provides a solar cell, comprising:

[0006] a substrate having a first surface and a second surface arranged oppositely;

[0007] a first doped layer located on one side of the first surface;

[0008] a first sub-diffusion layer located on one side of the first doped layer away from the substrate;

[0009] a second sub-diffusion layer located on one side of the first sub-diffusion layer away from the substrate;

[0010] wherein the first doped layer, the first sub-diffusion layer and the second sub-diffusion layer all have a first doped element, and the doping concentration of the first doped element in the first sub-diffusion layer is less than the doping concentration of the first doped element in the second sub-diffusion layer.

[0011] In some embodiments, the substrate has a second doped element, and the first doped element and the second doped element have different conductive types;

[0012] wherein the doping concentration of the first doped element in the first sub-diffusion layer is 4×10 19 cm-3 to 6 x 1019cm-3 19 cm -3 ; and / or,

[0013] the doping concentration of the first doping element in the second sub-diffusion layer is 0.8 x 1019cm-3 21 cm -3 to 1.2 x 1019cm-3 21 cm -3 .

[0014] In some embodiments, the first sub-diffusion layer and the second sub-diffusion layer each comprise silicon oxide.

[0015] In some embodiments, the thickness of the first sub-diffusion layer is less than or equal to half of the thickness of the second sub-diffusion layer in a direction perpendicular to the plane in which the substrate lies.

[0016] In some embodiments, the thickness of the first sub-diffusion layer is 20-30 nm in a direction perpendicular to the plane in which the substrate lies; and / or,

[0017] the thickness of the second sub-diffusion layer is 60-80 nm.

[0018] In some embodiments, the first doped layer is a first emitter layer; and / or,

[0019] the first doped layer comprises silicon and the first doping element doped in the silicon.

[0020] In some embodiments, the first doped layer comprises a first tunneling oxide layer, and a first doped polysilicon layer on a side of the first tunneling oxide layer distal to the substrate, the first doped polysilicon layer having the first doping element therein.

[0021] In some embodiments, the thickness of the first tunneling oxide layer is 0.8-2 nm in a direction perpendicular to the plane in which the substrate lies; and / or,

[0022] the thickness of the first doped polysilicon layer is 100-200 nm in a direction perpendicular to the plane in which the substrate lies.

[0023] In some embodiments, the doping concentration of the first doping element in the first doped polysilicon layer is 2 x 1019cm-3 20 cm -3 to 3 x 1019cm-3 20 cm -3 .

[0024] In some embodiments, the first doped layer further comprises:

[0025] a third diffusion sub-layer between the first tunneling oxide layer and the substrate, the third diffusion sub-layer having the first doping element.

[0026] In a second aspect, the present application provides a method for manufacturing a solar cell, comprising:

[0027] providing a substrate, the substrate having a first surface and a second surface oppositely arranged;

[0028] forming a first doping layer on the first surface;

[0029] forming a first diffusion sub-layer on a side of the first doping layer away from the substrate by a first deposition process, a doping source gas of the first doping element being provided at a first gas flow rate and a first radio frequency power during the first deposition process;

[0030] forming a second diffusion sub-layer on a side of the first diffusion sub-layer away from the substrate by a second deposition process, the doping source gas of the first doping element being provided at a second gas flow rate and a second radio frequency power during the second deposition process, wherein the first gas flow rate is less than the second gas flow rate, and the first radio frequency power is less than the second radio frequency power, so that a doping concentration of the first doping element in the first diffusion sub-layer is less than a doping concentration of the first doping element in the second diffusion sub-layer.

[0031] In some embodiments, the step of forming a first doping layer on the first surface comprises:

[0032] forming a first emitter layer on the first surface of the substrate, the first doping layer being the first emitter layer.

[0033] In some embodiments, the step of forming a first doping layer on the first surface comprises:

[0034] forming a first tunneling oxide layer on a side of the first surface of the substrate, and forming a first doped polysilicon layer on a side of the first tunneling oxide layer away from the substrate, the first doped polysilicon layer having the first doping element therein.

[0035] In a third aspect, the present application provides a stacked cell, comprising a top cell, a bonding layer and a bottom cell arranged in sequence, the bottom cell being any one of the solar cells described above.

[0036] In a fourth aspect, the present application provides a photovoltaic module, comprising:

[0037] A battery string is connected by a plurality of solar cells as described in any one of the above, or connected by a plurality of solar cells manufactured by the manufacturing method of any one of the above, or connected by the laminated cell described in the above;

[0038] A connecting member is used to electrically connect two adjacent solar cells;

[0039] An encapsulation film is used to cover the surface of the battery string;

[0040] A cover plate is used to cover the surface of the encapsulation film away from the battery string.

[0041] In the embodiments of the present application, the first doped layer, the first sub-diffusion layer and the second sub-diffusion layer are arranged on the first surface, and the doping concentration of the first doped element in the first sub-diffusion layer is less than the doping concentration of the first doped element in the second sub-diffusion layer. In the first aspect, the first sub-diffusion layer has a lower concentration of the first doped element, which reduces the formation of clusters of the first doped element on the interface (for example, reduces the formation of boron clusters in some embodiments), and reduces the interface state density. In the second aspect, the first sub-diffusion layer matches the thermal expansion coefficient of the first doped layer, which reduces micro-cracks. For example, the first sub-diffusion layer is boron-doped silicon dioxide, and the first doped layer includes a first tunneling oxide layer which is a tunneling oxide layer of silicon dioxide, so that the first sub-diffusion layer matches the thermal expansion coefficient of the first doped layer, the thermal stress can be reduced, thereby reducing micro-cracks. In the third aspect, the second sub-diffusion layer has a higher concentration of the first doped element, and the higher concentration of the first doped element forms a degenerate semiconductor state, which reduces the contact resistance with the metal electrode (the first electrode) and suppresses the injection of minority carriers, thereby improving the photoelectric conversion efficiency of the solar cell. For example, the second sub-diffusion layer is boron-doped silicon dioxide, and the higher concentration of boron-doped elements forms a degenerate semiconductor state, which reduces the contact resistance with the first electrode and suppresses the injection of minority carriers, thereby improving the photoelectric conversion efficiency of the solar cell. The embodiments of the present application have at least one of the above aspects, which reduces the interface state density, and / or improves the structural integrity of the solar cell, and / or reduces the contact resistance with the metal electrode, and / or suppresses the injection of minority carriers, thereby improving the photoelectric conversion efficiency of the solar cell. BRIEF DESCRIPTION OF DRAWINGS

[0042] In order to more clearly illustrate the technical solutions in the embodiments or exemplary embodiments of the present application, the drawings needed to be used in the description of the embodiments or exemplary embodiments will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creating laborious work.

[0043] Figure 1 A first cross-sectional structure schematic diagram of a solar cell provided for an embodiment of the present application.

[0044] Figure 2 A second cross-sectional structure schematic diagram of a solar cell provided for an embodiment of the present application.

[0045] Figure 3 A third cross-sectional structure schematic diagram of a solar cell provided for an embodiment of the present application.

[0046] Figure 4 A fourth cross-sectional structure schematic diagram of a solar cell provided for an embodiment of the present application.

[0047] Figure 5 A flow step schematic diagram of a manufacturing method of a solar cell provided for an embodiment of the present application.

[0048] Figure 6 A performance comparison schematic diagram of a solar cell of an embodiment of the present application and a solar cell of a related art.

[0049] Figure 7 A structure schematic diagram of a photovoltaic module provided for an embodiment of the present application.

[0050] FIG. 1 is a structure schematic diagram of a solar cell provided for an embodiment of the present application.

[0051] FIG. 2 is a structure schematic diagram of a photovoltaic module provided for an embodiment of the present application. DETAILED DESCRIPTION

[0052] In order to make the above objectives, features and advantages of the present application more clear and comprehensible, the specific embodiments of the present application will be described in detail below with reference to the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. However, the present application can be practiced in a number of different ways beyond the specific embodiments described herein and by one of ordinary skill in the art without departing from the spirit and scope of the present application, and it is therefore intended that all such variations be considered as falling within the scope of the present application. It should be understood that the descriptions of the present application are merely intended to explain and describe the application and its principles and the best modes of carrying out the application currently known to the present inventors. Therefore, the scope of the present application should be construed based on the appended claims rather than the detailed description.

[0053] In the description of the present application, it should be understood that, if there are terms such as "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. appear, these terms indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0054] In addition, if the terms "first", "second" appear, these terms are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features referred to. Therefore, the features defined as "first", "second" can explicitly or implicitly include at least one of the features. In the description of the present application, if the term "plurality" appears, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise explicitly specified and limited.

[0055] In the present application, unless otherwise explicitly specified and limited, if the terms "mounting", "connecting", "connecting", "fixing" and the like appear, these terms should be interpreted broadly. For example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements, unless otherwise explicitly limited. For those of ordinary skill in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0056] In the present application, unless specifically stated and limited otherwise, if there is a description of a first feature "on" or "under" a second feature, etc., it can mean that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium. Moreover, the first feature "over", "above" and "on" the second feature can be that the first feature is directly above or obliquely above the second feature, or only means that the first feature is higher than the second feature in horizontal height. The first feature "under", "below" and "under" the second feature can be that the first feature is directly below or obliquely below the second feature, or only means that the first feature is lower than the second feature in horizontal height.

[0057] It should be noted that if an element is referred to as being "fixed to" or "set to" another element, it can be directly on the other element or there can be an intermediate element. If an element is considered to be "connected" to another element, it can be directly connected to the other element or there can be an intermediate element. If present, the terms "vertical", "horizontal", "up", "down", "left", "right" and similar expressions used in the present application are only for illustrative purposes and do not mean the only implementation.

[0058] Referring to Figures 1 to 3 . Figure 1 A first cross-sectional structure schematic diagram of a solar cell provided by an embodiment of the present application. Figure 2 A second cross-sectional structure schematic diagram of a solar cell provided by an embodiment of the present application. Figure 3 A third cross-sectional structure schematic diagram of a solar cell provided by an embodiment of the present application.

[0059] In a first aspect, the present application provides a solar cell 100, which comprises a substrate 11, a first doped layer 12, a first sub-diffusion layer 13 and a second sub-diffusion layer 14. The substrate 11 has a first surface 111 and a second surface 112 arranged oppositely; the first doped layer 12 is located on one side of the first surface 111; the first sub-diffusion layer 13 is located on a side of the first doped layer 12 away from the substrate 11; the second sub-diffusion layer 14 is located on a side of the first sub-diffusion layer 13 away from the substrate 11; wherein the first doped layer 12, the first sub-diffusion layer 13 and the second sub-diffusion layer 14 all have a first doped element, and the doping concentration of the first doped element in the first sub-diffusion layer 13 is less than the doping concentration of the first doped element in the second sub-diffusion layer 14.

[0060] For example, the substrate 11 can have a doping element inside, which can be an N-type or P-type element. The N-type element can be a Group V element such as phosphorus (P), bismuth (Bi), antimony (Sb), or arsenic (As). The P-type element can be a Group III element such as boron (B), aluminum (Al), gallium (Ga), or indium (In). For example, when the substrate 11 is a P-type substrate, the doping element inside the substrate 11 is a P-type element. For another example, when the substrate 11 is an N-type substrate, the doping element inside the substrate 11 is an N-type element.

[0061] For example, the substrate 11 has a first surface 111 and a second surface 112 arranged opposite to each other. The first surface 111 and the second surface 112 are arranged opposite to each other along the thickness direction of the substrate 11. Either of the first surface 111 and the second surface 112 can be used to receive incident light.

[0062] For example, in some embodiments, the first surface 111 of the substrate 11 (e.g., the first surface 111 is a front surface) is a main light-receiving surface, the second surface 112 of the substrate 11 (e.g., the second surface 112 is a back surface) is a secondary light-receiving surface, and the first doping layer 12, the first sub-diffusion layer 13, and the second sub-diffusion layer 14 are arranged on the first surface 111 (front surface).

[0063] For example, in some other embodiments, the second surface 112 of the substrate 11 (e.g., the second surface 112 is a front surface) is a main light-receiving surface, the first surface 111 of the substrate 11 (e.g., the first surface 111 is a back surface) is a secondary light-receiving surface, and the first doping layer 12, the first sub-diffusion layer 13, and the second sub-diffusion layer 14 are arranged on the first surface 111 (back surface).

[0064] It can be understood that the light-receiving surface and the back surface are relative terms. The light-receiving surface is specifically a surface on which the substrate 11 is mainly irradiated by sunlight in a solar cell or in a photovoltaic module. With the development of solar cell technology, the back surface can also receive energy from sunlight, mainly from reflected or scattered light in the surrounding environment.

[0065] For example, in some embodiments, the first doping layer 12, the first sub-diffusion layer 13, and the second sub-diffusion layer 14 all have a first doping element. In some embodiments, when the first doping layer 12 includes one film layer, the first doping layer 12 has the first doping element. In some other embodiments, when the first doping layer 12 includes at least two film layers, at least one of the film layers of the first doping layer 12 has the first doping element. For example, when the first doping layer 12 includes two film layers, one of the film layers of the first doping layer 12 has the first doping element, and the other film layer of the first doping layer 12 does not have the first doping element.

[0066] For example, the first sub-diffusion layer 13 and the second sub-diffusion layer 14 can have a doping element, and the doping element can be of an N-type or a P-type. The N-type element can be a Group V element such as a phosphorus (P) element, a bismuth (Bi) element, an antimony (Sb) element, or an arsenic (As) element. The P-type element can be a Group III element such as a boron (B) element, an aluminum (Al) element, a gallium (Ga) element, or an indium (In) element.

[0067] For example, the substrate 11 can have a second doping element, and the first doping element and the second doping element can be of different conductive types. One of the first doping element and the second doping element can be of a P-type, and the other of the first doping element and the second doping element can be of an N-type.

[0068] For example, in some embodiments, the substrate 11 has a second doping element, and the second doping element is of a P-type. The substrate 11 can have a Group III doping element such as a boron (B) element, an aluminum (Al) element, a gallium (Ga) element, or an indium (In) element.

[0069] For example, in some other embodiments, the substrate 11 has a second doping element, and the second doping element is of an N-type. The substrate 11 can have a Group V doping element such as a phosphorus (P) element, a bismuth (Bi) element, an antimony (Sb) element, or an arsenic (As) element.

[0070] In the related art, there is no first sub-diffusion layer 13 and second sub-diffusion layer 14 with different doping concentrations, and there is only a single-layer diffusion layer. This has multiple problems. A first problem is that after a high-temperature annealing process, micro-cracks caused by stress mismatch between the film layers appear. A second problem is that the concentration of the doping element (for example, a boron element) decays by more than 30% from the surface to the interior of the single-layer diffusion layer, causing the lateral resistivity of the single-layer diffusion layer to be too large, for example, greater than 200 Ω / sq, which affects the collection of carriers. A third problem is that the single-layer diffusion layer needs to have a large thickness, for example, greater than 100 nanometers, which increases the manufacturing time and limits the production capacity.

[0071] For example, the first doped layer 12, the first sub-diffusion layer 13 and the second sub-diffusion layer 14 are disposed on the first surface 111, and the first doped element in the first sub-diffusion layer 13 has a lower doping concentration than the first doped element in the second sub-diffusion layer 14. In a first aspect, the first sub-diffusion layer 13 has a lower concentration of the first doped element, which reduces the formation of clusters of the first doped element on the interface (for example, reduces boron cluster formation in some embodiments), thereby reducing the interface state density. In a second aspect, the first sub-diffusion layer 13 matches the thermal expansion coefficient of the first doped layer 12, thereby reducing micro-cracks. For example, the first sub-diffusion layer 13 is boron-doped silicon dioxide, and the first doped layer 12 includes a first tunneling oxide layer, which is a tunneling oxide layer of silicon dioxide. In this way, the first sub-diffusion layer 13 can match the thermal expansion coefficient of the first doped layer 12, and the thermal stress can be reduced from 1.2 GPa in the prior art to 0.8 GPa in the embodiments of the present application, thereby reducing micro-cracks.

[0072] For example, the first doped layer 12, the first sub-diffusion layer 13 and the second sub-diffusion layer 14 are disposed on the first surface 111, and the first doped element in the first sub-diffusion layer 13 has a lower doping concentration than the first doped element in the second sub-diffusion layer 14. In a first aspect, the second sub-diffusion layer 14 has a higher concentration of the first doped element, which forms a degenerate semiconductor state, thereby reducing the contact resistance with the metal electrode (the first electrode 16) and suppressing the injection of minority carriers, thereby improving the photoelectric conversion efficiency of the solar cell. For example, the second sub-diffusion layer 14 is boron-doped silicon dioxide, and the higher concentration of boron-doped elements forms a degenerate semiconductor state, thereby reducing the contact resistance with the first electrode 16 and suppressing the injection of minority carriers, thereby improving the photoelectric conversion efficiency of the solar cell.

[0073] In the embodiments of the present application, the first doped layer 12, the first sub-diffusion layer 13 and the second sub-diffusion layer 14 are arranged on the first surface 111, the doping concentration of the first doped element in the first sub-diffusion layer 13 is less than the doping concentration of the first doped element in the second sub-diffusion layer 14. In the first aspect, the first sub-diffusion layer 13 has a lower concentration of the first doped element, which reduces the formation of clusters of the first doped element on the interface (for example, reduces the formation of boron clusters in some embodiments), and reduces the interface state density. In the second aspect, the first sub-diffusion layer 13 matches the thermal expansion coefficient of the first doped layer 12, which reduces micro-cracks. For example, the first sub-diffusion layer 13 is doped with boron elements in silicon dioxide, and the first doped layer 12 includes a first tunneling oxide layer, which is a tunneling oxide layer of silicon dioxide, so that the first sub-diffusion layer 13 matches the thermal expansion coefficient of the first doped layer 12, and the thermal stress is reduced from 1.2 GPa in the prior art to 0.8 GPa in the embodiments of the present application, thereby reducing micro-cracks. In the third aspect, the second sub-diffusion layer 14 has a higher concentration of the first doped element, and the higher concentration of the first doped element forms a degenerate semiconductor state, which reduces the contact resistance with the metal electrode (the first electrode 16) and suppresses the injection of minority carriers, thereby improving the photoelectric conversion efficiency of the solar cell. For example, the second sub-diffusion layer 14 is doped with boron elements in silicon dioxide, and the higher concentration of boron doped elements forms a degenerate semiconductor state, which reduces the contact resistance with the first electrode 16 and suppresses the injection of minority carriers, thereby improving the photoelectric conversion efficiency of the solar cell. The embodiments of the present application have at least one of the above aspects, which reduces the interface state density, and / or improves the structural integrity of the solar cell, and / or reduces the contact resistance with the metal electrode, and / or suppresses the injection of minority carriers, thereby improving the photoelectric conversion efficiency of the solar cell.

[0074] In some embodiments, the substrate 11 has a second doped element, and the first doped element and the second doped element have different conductive types; wherein the doping concentration of the first doped element in the first sub-diffusion layer 13 is 4×10 19 cm -3 to 6×10 19 cm -3 ; and / or, the doping concentration of the first doped element in the second sub-diffusion layer 14 is 0.8×10 21 cm -3 to 1.2×10 21 cm -3 .

[0075] For example, the doping concentration of the first doped element in the first sub-diffusion layer 13 is 4×10 19 cm -3 to 6×10 19 cm -3 , for example, the doping concentration of the first doped element in the first sub-diffusion layer 13 can be 4×1019 cm -3 , 4.5 x 10 19 cm -3 , 5 x 10 19 cm -3 , 5.5 x 10 19 cm -3 , 6 x 10 19 cm -3 , any of which can reduce the formation of clusters of the first doping element (e.g., boron clusters in some embodiments) at the interface and reduce the interface state density.

[0076] For example, the doping concentration of the first doping element in the second sub-diffusion layer 14 can be 0.8 x 10 21 cm -3 to 1.2 x 10 21 cm -3 , e.g., the doping concentration of the first doping element in the second sub-diffusion layer 14 can be 0.8 x 10 21 cm -3 , 0.9 x 10 21 cm -3 , 1 x 10 21 cm -3 , 1.1 x 10 21 cm -3 , 1.2 x 10 21 cm -3 , any of which can form degenerate semiconductor states for the first doping element, reduce the contact resistance with the metal electrode (the first electrode 16), and suppress the minority carrier injection.

[0077] In some embodiments, the first sub-diffusion layer 13 and the second sub-diffusion layer 14 each include silicon oxide.

[0078] For example, in some embodiments, the first doping element is boron, the materials of the first sub-diffusion layer 13 and the second sub-diffusion layer 14 each include silicon oxide and boron, and the doping concentration of the first doping element in the first sub-diffusion layer 13 is less than the doping concentration of the first doping element in the second sub-diffusion layer 14.

[0079] In some embodiments, the thickness of the first sub-diffusion layer 13 in the direction of the plane in which the vertical base 11 lies is less than or equal to half the thickness of the second sub-diffusion layer 14.

[0080] For example, in the direction of the plane in which the vertical base 11 lies, the thickness of the first sub-diffusion layer 13 is less than or equal to half the thickness of the second sub-diffusion layer 14. Figure 1In the first direction X, the thickness of the first sub-diffusion layer 13 is less than or equal to half the thickness of the second sub-diffusion layer 14. The first sub-diffusion layer 13 is used to reduce the formation of first doped element clusters on the interface (e.g., in some embodiments, it reduces the formation of boron clusters), thereby reducing the interface state density. The first sub-diffusion layer 13 is also used to match the thermal expansion coefficient of the first doped layer 12, reducing microcracks. Therefore, the thickness of the first sub-diffusion layer 13 does not need to be too large relative to the second sub-diffusion layer 14, to avoid increasing the thickness of the solar cell and the resistance at this point. The second sub-diffusion layer 14 is used to form degenerate semiconductor states of the first doped element, reducing the contact resistance with the first electrode 16, while suppressing minority carrier injection. Therefore, the thickness of the second sub-diffusion layer 14 needs to be larger relative to the first sub-diffusion layer 13, to avoid poor contact with the metal electrode when the thickness is too small.

[0081] In some embodiments, the thickness of the first sub-diffusion layer 13 is 20 nanometers to 30 nanometers in the direction perpendicular to the plane of the substrate 11; and / or, the thickness of the second sub-diffusion layer 14 is 60 nanometers to 80 nanometers.

[0082] For example, the thickness of the first sub-diffusion layer 13 is 20 nanometers to 30 nanometers, and the thickness of the first sub-diffusion layer 13 can be any value among 20 nanometers, 22 nanometers, 25 nanometers, 28 nanometers and 30 nanometers.

[0083] For example, the thickness of the second sub-diffusion layer 14 is 60 nanometers to 80 nanometers, and the thickness of the second sub-diffusion layer 14 can be any value among 60 nanometers, 65 nanometers, 70 nanometers, 75 nanometers and 80 nanometers.

[0084] In some implementations, such as Figure 1 As shown, the first doped layer 12 is a first emitter layer 121; and / or, the first doped layer 12 includes silicon and a first doping element doped in silicon.

[0085] For example, such as Figure 1 As shown, the first doped layer 12 is the first emitter layer 121, and at this time, the first emitter layer 121, the first sub-diffusion layer 13, and the second sub-diffusion layer 14 are formed in sequence on the first surface 111.

[0086] For example, such as Figure 1 As shown, in some embodiments, the first emitter layer 121 includes silicon and a first dopant element doped in the silicon, such as boron.

[0087] In some implementations, such as Figure 2 As shown, the first doped layer 12 includes a first tunneling oxide layer 122 and a first doped polysilicon layer 123 located on the side of the first tunneling oxide layer 122 away from the substrate 11, wherein the first doped polysilicon layer 123 has a first doping element.

[0088] As shown in FIG. 1A, the first surface 111 is formed with a first tunneling oxide layer 122, a first doped polysilicon layer 123, a first sub-diffusion layer 13, and a second sub-diffusion layer 14, which are sequentially stacked. Figure 2 As shown in FIG. 1A, the first surface 111 is formed with a first tunneling oxide layer 122, a first doped polysilicon layer 123, a first sub-diffusion layer 13, and a second sub-diffusion layer 14, which are sequentially stacked.

[0089] As shown in FIG. 1A, the first surface 111 is formed with a first tunneling oxide layer 122, a first doped polysilicon layer 123, a first sub-diffusion layer 13, and a second sub-diffusion layer 14, which are sequentially stacked.

[0090] As shown in FIG. 1A, the first surface 111 is formed with a first tunneling oxide layer 122, a first doped polysilicon layer 123, a first sub-diffusion layer 13, and a second sub-diffusion layer 14, which are sequentially stacked. Figure 2 As shown in FIG. 1A, the first surface 111 is formed with a first tunneling oxide layer 122, a first doped polysilicon layer 123, a first sub-diffusion layer 13, and a second sub-diffusion layer 14, which are sequentially stacked.

[0091] As shown in FIG. 1A, the first surface 111 is formed with a first tunneling oxide layer 122, a first doped polysilicon layer 123, a first sub-diffusion layer 13, and a second sub-diffusion layer 14, which are sequentially stacked. Figure 2 As shown in FIG. 1A, the first surface 111 is formed with a first tunneling oxide layer 122, a first doped polysilicon layer 123, a first sub-diffusion layer 13, and a second sub-diffusion layer 14, which are sequentially stacked.

[0092] As shown in FIG. 1A, the first surface 111 is formed with a first tunneling oxide layer 122, a first doped polysilicon layer 123, a first sub-diffusion layer 13, and a second sub-diffusion layer 14, which are sequentially stacked. Figure 2 As shown in FIG. 1A, the first surface 111 is formed with a first tunneling oxide layer 122, a first doped polysilicon layer 123, a first sub-diffusion layer 13, and a second sub-diffusion layer 14, which are sequentially stacked.

[0093] As shown in FIG. 1A, the first surface 111 is formed with a first tunneling oxide layer 122, a first doped polysilicon layer 123, a first sub-diffusion layer 13, and a second sub-diffusion layer 14, which are sequentially stacked. Figure 2 As shown in FIG. 1A, the first surface 111 is formed with a first tunneling oxide layer 122, a first doped polysilicon layer 123, a first sub-diffusion layer 13, and a second sub-diffusion layer 14, which are sequentially stacked. 20 cm -3 to 3×10 20 cm -3 .

[0094] As shown in FIG. 1A, the first surface 111 is formed with a first tunneling oxide layer 122, a first doped polysilicon layer 123, a first sub-diffusion layer 13, and a second sub-diffusion layer 14, which are sequentially stacked. 20 cm -3 , 2.2×10 20 cm -3 , 2.5×10 20 cm -3 , 2.8×10 20 cm -3 , 3×10 20cm -3 Any value in the range.

[0095] In some implementations, such as Figure 3 As shown, the first doped layer 12 further includes a third diffuser layer 120, which is located between the first tunneling oxide layer 122 and the substrate 11, and the third diffuser layer 120 has a first doping element.

[0096] For example, such as Figure 3 As shown, when the first doped layer 12 is located on the front side of the substrate, the first doped layer 12 includes a third diffusion sub-layer 120, a first tunneling oxide layer 122, and a first doped polysilicon layer 123. At this time, the third diffusion sub-layer 120, the first tunneling oxide layer 122, the first doped polysilicon layer 123, the first sub-diffusion layer 13, and the second sub-diffusion layer 14 are formed in sequence on the first surface 111.

[0097] For example, the third diffused sublayer 120 can be formed when the first doped polysilicon layer 123 diffuses into the substrate 11 during the formation of the first doped polysilicon layer 123, so that the third diffused sublayer 120 has the function of an emitter layer. However, the third diffused sublayer 120 can also be fabricated by a separate process, which is not limited here.

[0098] It should be noted that, as Figures 1 to 3 The diagram illustrates a tunnel oxide passivated contact (TOPCon) solar cell. The solar cell 100 also includes a first passivation layer 15 located on the side of the second sub-diffusion layer 14 away from the first sub-diffusion layer 13, and a first electrode 16; the solar cell 100 further includes a second tunneling oxide layer 21, a second doped polycrystalline silicon layer 22, a second passivation layer 23, and a second electrode 24 sequentially stacked on the second surface 112. It should be noted that the structure of the tunnel oxide passivated contact (TOPCon) solar cell is not limited to... Figures 1 to 3 As shown, for example, a first passivation layer 15 and a first antireflection layer may be sequentially stacked on one side of the first surface 111, and a second passivation layer 23 and a second antireflection layer may be sequentially stacked on one side of the second surface 112; the material of the passivation layer may be at least one of AlOx (alumina), SiOx (silicon oxide), a-Si:H(i) (amorphous silicon), etc.; the material of the antireflection layer may be at least one of SiNxOy (silicon oxynitride) and SiNx (silicon nitride).

[0099] For example, one of the first electrode 16 and the second electrode 24 is a positive electrode, and the other of the first electrode 16 and the second electrode 24 is a negative electrode.

[0100] It should be noted that, as Figures 1 to 3As shown in FIG. 1, the first doped layer 12, the first sub-diffusion layer 13 and the second sub-diffusion layer 14 are located at the first surface 111 of the solar cell 100, and the first surface 111 is the front surface of the solar cell 100. In some other embodiments, the first doped layer 12, the first sub-diffusion layer 13 and the second sub-diffusion layer 14 can also be located at the first surface 111, and the first surface 111 is the back surface of the solar cell 100. For example, the first doped layer 12 comprises a first tunnel oxide layer 122 and a first doped polysilicon layer 123 located at the side of the first tunnel oxide layer 122 away from the substrate 11, and the first tunnel oxide layer 122 and the first doped polysilicon layer 123 are located at the back surface of the solar cell 100.

[0101] It should be noted that, as shown in FIG. 1, the first doped layer 12, the first sub-diffusion layer 13 and the second sub-diffusion layer 14 are located at the first surface 111 of the solar cell 100, and the first surface 111 is the front surface of the solar cell 100. In some other embodiments, the first doped layer 12, the first sub-diffusion layer 13 and the second sub-diffusion layer 14 can also be located at the first surface 111, and the first surface 111 is the back surface of the solar cell 100. For example, the first doped layer 12 comprises a first tunnel oxide layer 122 and a first doped polysilicon layer 123 located at the side of the first tunnel oxide layer 122 away from the substrate 11, and the first tunnel oxide layer 122 and the first doped polysilicon layer 123 are located at the back surface of the solar cell 100. Figures 1 to 3 As shown in FIG. 1, in the TOPCon cell, the first surface 111 of the substrate 11 is the front surface, and the first surface 111 can further have a plurality of textured structures R1, which can be pyramid structures or inverted pyramid structures, without limitation.

[0102] It should be noted that, as shown in FIG. 1, the first doped layer 12, the first sub-diffusion layer 13 and the second sub-diffusion layer 14 are located at the first surface 111 of the solar cell 100, and the first surface 111 is the front surface of the solar cell 100. In some other embodiments, the first doped layer 12, the first sub-diffusion layer 13 and the second sub-diffusion layer 14 can also be located at the first surface 111, and the first surface 111 is the back surface of the solar cell 100. For example, the first doped layer 12 comprises a first tunnel oxide layer 122 and a first doped polysilicon layer 123 located at the side of the first tunnel oxide layer 122 away from the substrate 11, and the first tunnel oxide layer 122 and the first doped polysilicon layer 123 are located at the back surface of the solar cell 100. Figures 1 to 3 As shown in FIG. 1, the first doped layer 12, the first sub-diffusion layer 13 and the second sub-diffusion layer 14 are located at the first surface 111 of the solar cell 100, and the first surface 111 is the front surface of the solar cell 100. In some other embodiments, the first doped layer 12, the first sub-diffusion layer 13 and the second sub-diffusion layer 14 can also be located at the first surface 111, and the first surface 111 is the back surface of the solar cell 100. For example, the first doped layer 12 comprises a first tunnel oxide layer 122 and a first doped polysilicon layer 123 located at the side of the first tunnel oxide layer 122 away from the substrate 11, and the first tunnel oxide layer 122 and the first doped polysilicon layer 123 are located at the back surface of the solar cell 100.

[0103] It should be noted that, as shown in FIG. 1, the first doped layer 12, the first sub-diffusion layer 13 and the second sub-diffusion layer 14 are located at the first surface 111 of the solar cell 100, and the first surface 111 is the front surface of the solar cell 100. In some other embodiments, the first doped layer 12, the first sub-diffusion layer 13 and the second sub-diffusion layer 14 can also be located at the first surface 111, and the first surface 111 is the back surface of the solar cell 100. For example, the first doped layer 12 comprises a first tunnel oxide layer 122 and a first doped polysilicon layer 123 located at the side of the first tunnel oxide layer 122 away from the substrate 11, and the first tunnel oxide layer 122 and the first doped polysilicon layer 123 are located at the back surface of the solar cell 100. Figure 4 , Figure 4 FIG. 4 is a fourth cross-sectional structure schematic diagram of a solar cell provided by an embodiment of the present application, Figure 4A structure of a BC battery is exemplarily shown. The solar cell 100 includes a substrate 31, a first doped layer 32, a first sub-diffusion layer 33, and a second sub-diffusion layer 34. The substrate 31 has a first surface 311 and a second surface 312 oppositely arranged. The first surface 311 is provided with first doped regions 311a and second doped regions 311b arranged alternately, and interval regions 311c between the first doped regions 311a and the second doped regions 311b. The first doped layer 32, the first sub-diffusion layer 33, and the second sub-diffusion layer 34 can be arranged on one of the first doped regions 311a and the second doped regions 311b. In this case, the first electrode 391 and the second electrode 392 are arranged on the back surface of the solar cell 100. The first electrode 391 can be arranged on the first doped regions 311a, and the second electrode 392 can be arranged on the second doped regions 311b. Figure 4 The solar cell 100 includes, in the first doped regions 311a, a tunneling oxide layer 35, the first doped layer 32, the first sub-diffusion layer 33, the second sub-diffusion layer 34, a first passivation layer 37, a first anti-reflection layer 38, and the first electrode 391 arranged sequentially, for example. The first doped layer 32 can be a first emitter layer 321. Figure 4 The solar cell 100 includes, in the second doped regions 311b, the tunneling oxide layer 35, a second emitter layer 36, the first passivation layer 37, the first anti-reflection layer 38, and the second electrode 392 arranged sequentially. Figure 4 The solar cell 100 includes, in the second surface 312, a second passivation layer 41 and a second anti-reflection layer 42 arranged sequentially. The first emitter layer 321 and the second emitter layer 36 are emitter layers of different conductive types, for example, the first emitter layer 321 is a P-type emitter layer, and the second emitter layer 36 is an N-type emitter layer. It should be noted that the structure of the BC battery is not limited to Figure 4 as shown.

[0104] Please refer to Figure 5 . Figure 5 A flow step diagram of a manufacturing method of a solar cell provided by an embodiment of the present application is shown.

[0105] In a second aspect, based on the same application concept, the present application further provides a manufacturing method of a solar cell. The solar cell 100 of any one of the above embodiments can be manufactured by using the manufacturing method of the solar cell. As shown in the drawings, Figure 4 The manufacturing method of the solar cell includes: a step S100, a step S200, a step S300, and a step S400.

[0106] In the step S100, a substrate is provided. The substrate has a first surface and a second surface arranged oppositely.

[0107] For example, a substrate 11 is provided, which has a first surface 111 and a second surface 112 arranged oppositely.

[0108] In step S200, a first doped layer is formed on the first surface.

[0109] For example, the first doped layer 12 is formed on the first surface 111.

[0110] For example, as shown in FIG. 1, the first doped layer 12 is formed on the first surface 111. Figure 1 For example, after the first doped layer 12 is formed on the first surface 111, the first doped layer 12 is a first emitter layer 121. The first emitter layer 121 can be formed by ion implantation process to dope the first doped element on the first surface 111 of the substrate 11, for example, boron element can be doped in a silicon substrate by ion implantation process.

[0111] For example, as shown in FIG. 2, after the first doped layer 12 is formed on the first surface 111, the first doped layer 12 includes a first tunneling oxide layer 122 and a first doped polysilicon layer 123 located on a side of the first tunneling oxide layer 122 away from the substrate 11. The first tunneling oxide layer 122 can be formed by thermal oxidation or atomic layer deposition (ALD) process to form a silicon dioxide material; and then the first doped polysilicon layer 123 is formed on the side of the first tunneling oxide layer 122 away from the substrate 11. Figure 2 For example, as shown in FIG. 3, after the first doped layer 12 is formed on the first surface 111, the first doped layer 12 includes a first tunneling oxide layer 122 and a first doped polysilicon layer 123 located on a side of the first tunneling oxide layer 122 away from the substrate 11. The first tunneling oxide layer 122 can be formed by thermal oxidation or atomic layer deposition (ALD) process to form a silicon dioxide material; and then the first doped polysilicon layer 123 is formed on the side of the first tunneling oxide layer 122 away from the substrate 11.

[0112] Figure 3 For example, after the first doped layer 12 is formed on the first surface 111, when the first doped polysilicon layer 123 is formed, the first doped element in the first doped polysilicon layer 123 can diffuse into the substrate 11 to form a third diffusion sub-layer 120, which can have the function of an emitter layer. At this time, the third diffusion sub-layer 120, the first tunneling oxide layer 122, the first doped polysilicon layer 123, the first sub-diffusion layer 13, and the second sub-diffusion layer 14 are sequentially stacked on the first surface 111.

[0113] In step S300, a first sub-diffusion layer is formed on a side of the first doped layer away from the substrate by a first deposition process, during which a doping source gas of the first doped element is provided at a first gas flow rate, and a radio frequency power is a first radio frequency power.

[0114] For example, the first sub-diffusion layer 13 is formed on a side of the first doped layer 12 away from the substrate 11 by a first deposition process, during which a doping source gas of the first doped element is provided at a first gas flow rate, and a radio frequency power is a first radio frequency power.

[0115] For example, during the first deposition process, the doping source gas of the first doped element is provided at a first gas flow rate, a deposition pressure is a first deposition pressure, and a radio frequency power is a first radio frequency power.​

[0116] For example, taking the first sub-diffusion layer 13 as an example, the first deposition process is carried out by providing a boron-doped silicon dioxide, the gas flow of silane (SiH4) is 480-520sccm, for example, the gas flow of silane is 500sccm, the gas flow of diborane (B2H6) is 8-12sccm, for example, the gas flow of diborane is 10sccm, and the gas flow of diborane is the first gas flow; the first deposition pressure is 0.4-0.6Torr, for example, the first deposition pressure is 0.5Torr, the first radio frequency power is 180-220W, for example, the first radio frequency power is 200W, and the first deposition rate is 2-4nm / min, for example, the first deposition rate is 3nm / min. The small first gas flow, the small first deposition pressure, and the small first radio frequency power result in a small first deposition rate, a smaller ratio of the gas flow of silane to the gas flow of diborane, an increased density of Si-O bonds, and a dense amorphous network of the first sub-diffusion layer 13, which can improve the passivation quality. In addition, the small first gas flow, the small first deposition pressure, and the small first radio frequency power also result in a small doping concentration of the first doping element in the first doping layer 12; and the small first radio frequency power also reduces the plasma ion energy, avoids damage to the interface caused by bombardment, and thus improves the passivation effect.

[0117] In step S400, a second sub-diffusion layer is formed on the side of the first sub-diffusion layer away from the substrate by a second deposition process, the second deposition process is carried out by providing a doping source gas of the first doping element at a second gas flow and a radio frequency power of a second radio frequency power, wherein the first gas flow is less than the second gas flow, and the first radio frequency power is less than the second radio frequency power, so that the doping concentration of the first doping element in the first sub-diffusion layer is less than the doping concentration of the first doping element in the second sub-diffusion layer.

[0118] For example, the second sub-diffusion layer 14 is formed on the side of the first sub-diffusion layer 13 away from the substrate 11 by a second deposition process, the second deposition process is carried out by providing a doping source gas of the first doping element at a second gas flow and a radio frequency power of a second radio frequency power, wherein the first gas flow is less than the second gas flow, and the first radio frequency power is less than the second radio frequency power, so that the doping concentration of the first doping element in the first sub-diffusion layer is less than the doping concentration of the first doping element in the second sub-diffusion layer.

[0119] For example, the second deposition process is carried out by providing a doping source gas of the first doping element at a second gas flow, a deposition pressure of a second deposition pressure, and a radio frequency power of a second radio frequency power. The first gas flow is less than the second gas flow, the first deposition pressure is less than the second deposition pressure, and the first radio frequency power is less than the second radio frequency power.

[0120] For example, taking the second sub-diffusion layer 14 doped with boron in silicon dioxide as an example, during the second deposition process, the gas flow of silane (SiH4) is 180-220 sccm, for example, the gas flow of silane is 200 sccm, the gas flow of diborane (B2H6) is 30-50 sccm, for example, the gas flow of diborane is 40 sccm, the gas flow of diborane is the second gas flow, the second deposition pressure is 1.8-2.2 Torr, for example, the second deposition pressure is 2 Torr, and the second radio frequency power is 750-850 W, for example, the second radio frequency power is 800 W. The second deposition pressure is large, and the second radio frequency power is large, so that the second deposition rate is large, which is helpful for high-speed deposition of the second sub-diffusion layer 14 and reduces the deposition time. In addition, the second gas flow is large, the second deposition pressure is large, and the second radio frequency power is large, so that the doping concentration of the first doping element in the second sub-diffusion layer 14 is large, for example, the large second radio frequency power improves the ionization rate of the plasma, and the boron doping efficiency can be improved.

[0121] For example, in addition, during or after the second deposition process, an in-situ plasma treatment step of hydrogen element is further included, the gas flow of hydrogen is 450-550 sccm, and the processing time is 25-35 s, for example, the gas flow of hydrogen is 500 sccm, and the processing time is 30 s.

[0122] For example, taking the second sub-diffusion layer 14 doped with boron in silicon dioxide as an example, during the second deposition process, in the in-situ plasma treatment step of hydrogen element, the hydrogen element plasma can etch the weak Si-Si bond in the second sub-diffusion layer 14 to form Si-H bond passivation and form H filling vacancies, so that the microcracks can be repaired.

[0123] For example, compared with the diffusion layer with only a single layer in the related art, in the embodiment of the present application, the total thickness of the first sub-diffusion layer 13 and the second sub-diffusion layer 14 is smaller, and the second sub-diffusion layer 14 can be deposited at a high speed, which reduces the total deposition time of the first sub-diffusion layer 13 and the second sub-diffusion layer 14, thereby reducing the manufacturing time, improving the production capacity, and solving the problem in the third aspect.

[0124] In some embodiments, the method for manufacturing a solar cell includes the steps of: Figure 1 For example, as shown in the solar cell, the step of forming the first doped layer 12 on the first surface 111 (step S200) includes: doping the first emitter layer 121 on the first surface 111 of the substrate 11, and the first doped layer 12 is the first emitter layer 121.

[0125] In some embodiments, the method for manufacturing a solar cell includes the steps of: Figure 2The first doped layer 12 is formed on the first surface 111 of the substrate 11. The first doped layer 12 includes a first diffusion sub-layer 120, a first tunneling oxide layer 122, and a first doped polysilicon layer 123. The first diffusion sub-layer 120 is formed on the first surface 111 of the substrate 11. The first tunneling oxide layer 122 is formed on the first diffusion sub-layer 120. The first doped polysilicon layer 123 is formed on the first tunneling oxide layer 122. The first doped polysilicon layer 123 has a first doped element. The first doped element in the first doped polysilicon layer 123 diffuses into the substrate 11 to form the first diffusion sub-layer 120.

[0126] It should be noted that the method for manufacturing the solar cell is based on the same application concept as the solar cell 100 described above. The method for manufacturing the solar cell has the same or similar effects as the solar cell 100 described above, and will not be described here again. At the same time, Figure 3 The first doped layer 12 is formed on the first surface 111 of the substrate 11. The first doped layer 12 includes a first diffusion sub-layer 120, a first tunneling oxide layer 122, and a first doped polysilicon layer 123. The first diffusion sub-layer 120 is formed on the first surface 111 of the substrate 11. The first tunneling oxide layer 122 is formed on the first diffusion sub-layer 120. The first doped polysilicon layer 123 is formed on the first tunneling oxide layer 122. The first doped polysilicon layer 123 has a first doped element. The first doped element in the first doped polysilicon layer 123 diffuses into the substrate 11 to form the first diffusion sub-layer 120.

[0127] It should be noted that the method for manufacturing the solar cell is based on the same application concept as the solar cell 100 described above. The method for manufacturing the solar cell has the same or similar effects as the solar cell 100 described above, and will not be described here again. At the same time, Figures 1 to 3 For example, the first surface 111 is the front surface of the substrate 11, and the method for manufacturing the solar cell can form the first doped layer 12, the first diffusion sub-layer 13, and the second diffusion sub-layer 14 on the front surface of the substrate 11. In other embodiments, the first surface 111 is the back surface of the substrate 11, and the method for manufacturing the solar cell can form the first doped layer 12, the first diffusion sub-layer 13, and the second diffusion sub-layer 14 on the back surface of the substrate 11.

[0128] It should be noted that the method for manufacturing the solar cell is based on the same application concept as the solar cell 100 described above. The method for manufacturing the solar cell has the same or similar effects as the solar cell 100 described above, and will not be described here again. At the same time, Figure 3The solar cell is used as an example to illustrate the manufacturing method of the solar cell in detail. The manufacturing method of the solar cell includes steps S11-S19 in sequence. S11, a substrate 11 is provided, cleaned and textured. S12, a first emitter layer 121 is formed on the first surface. S13, a first tunneling oxide layer 122 is formed. The first tunneling oxide layer 122 can be formed by thermal oxidation or ALD process to form a silicon dioxide material. S14, a first doped polysilicon layer is formed. S15, a first sub-diffusion layer 13 is formed by providing a gas flow of 500 sccm of silane (SiH4) and a gas flow of 10 sccm of diborane (B2H6) during a first deposition process. S16, a second sub-diffusion layer 14 is formed by providing a gas flow of 200 sccm of silane (SiH4) and a gas flow of 40 sccm of diborane (B2H6) during a second deposition process. S17, first annealing at a temperature of 650 o C-700 o C (for example, 650 o C) for 10 minutes, which plays a role of passivating the crystal, for example, converting amorphous silicon into microcrystalline silicon, and hydrogen atoms migrate to the Si / SiO2 interface to saturate dangling bonds. S18, second annealing at a temperature of 900 o C-1000 o C (for example, 950 o C) for 5 minutes, which plays a role of activating boron, for example, boron atoms are converted from interstitial sites to substitutional sites, while oxygen and free boron form B2O3, preventing B diffusion to the subsequent passivation layer and inhibiting boron outdiffusion. S18, a first passivation layer 15 is formed. S19, a first electrode 16 is formed. The manufacturing method of the film layer on the second surface 112 can be any prior art, which is not described here again. When manufacturing Figure 1 When manufacturing the solar cell 100 shown in FIG. 1, the manufacturing method of the solar cell can not include steps S13 and S14. Figure 2 When manufacturing the solar cell 100 shown in FIG. 1, the manufacturing method of the solar cell can not include step S12.

[0129] Please refer to Figure 6 , Figure 6 The performance of a solar cell according to an embodiment of the present application is compared with that of a solar cell according to a related art. The comparative example 1 according to the related art is a single-layer diffusion layer, and the embodiment 1 according to the present application includes a first sub-diffusion layer 13 and a second sub-diffusion layer 14. The comparative example 1 and the embodiment 1 are both TOPCon cells, and both use an N-type substrate doped with a second doping element of phosphorus element. The first doped layer 12, the first sub-diffusion layer 13 and the second sub-diffusion layer 14 in the embodiment 1 all have a first doping element of boron element. The comparative example 1 and the embodiment 1 both undergo the same two annealings. The first annealing is at a temperature of 650 oC for 10 minutes, and the second annealing is at 950 o C for 5 minutes; the single diffusion layer in Comparative Example 1 covers the same functional area as the first sub-diffusion layer 13 and the second sub-diffusion layer 14 in Example 1. From Figure 5 As can be seen from the above, compared with Comparative Example 1, the interface state density of Example 1 of the present application is reduced by 43.8%, the contact resistance with the first electrode 16 is reduced by 52%, and the minority carrier lifetime is increased by 86.7%.

[0130] In a third aspect, based on the same application concept, the present application further provides a stacked cell, which comprises a top cell, a bonding layer and a bottom cell arranged in sequence, and the bottom cell is the solar cell 100 of any one of the above.

[0131] For example, in some embodiments, the top cell can be a perovskite solar cell, which comprises a laminated first transport layer, a perovskite substrate, a second transport layer, a transparent conductive layer and an anti-reflection layer. The first transport layer is opposite to the bottom cell. The first transport layer can be one of an electron transport layer or a hole transport layer, and the second transport layer can be the other one of the electron transport layer or the hole transport layer.

[0132] It should be noted that the stacked cell of the present application and the solar cell 100 of any one of the above are based on the same application concept, and the stacked cell and the solar cell 100 of any one of the above have the same or similar effects, which will not be described here.

[0133] Please refer to Figure 7 , Figure 7 for a structural schematic diagram of a photovoltaic module provided by the present application.

[0134] In a fourth aspect, based on the same application concept, the present application further provides a photovoltaic module 200, which comprises: a cell string 203 connected by a plurality of solar cells 100 of any one of the above, or connected by a plurality of solar cells 100 manufactured by the manufacturing method of any one of the above, or connected by a stacked cell of any one of the above; a connecting component 204 for electrically connecting two adjacent solar cells 100; an encapsulant film 202 for covering the surface of the cell string 203; and a cover plate 201 for covering the surface of the encapsulant film 202 away from the cell string 203.

[0135] For example, in some embodiments, the connecting component 204 can include a conductive strip, and a plurality of cell strings 203 can be electrically connected by the conductive strip. The encapsulant film 202 covers the front surface and the back surface of the solar cell or the stacked solar cell.

[0136] For example, in some embodiments, the encapsulation adhesive film 202 can be an organic encapsulation adhesive film such as an ethylene-vinyl acetate copolymer (EVA) adhesive film, a polyolefin elastomer (POE) adhesive film, or a polyethylene terephthalate (PET) adhesive film.

[0137] For example, in some embodiments, the cover plate 201 can be a glass cover plate, a plastic cover plate, or a cover plate having a light-transmitting function.

[0138] For example, in some embodiments, the surface of the cover plate 201 facing the encapsulation layer can be a concave-convex surface, thereby increasing the utilization rate of incident light.

[0139] It should be noted that the photovoltaic module 200 of the present application and the solar cell 100 of any one of the above embodiments are based on the same application concept, and the photovoltaic module 200 and the solar cell 100 of any one of the above embodiments have the same or similar effects, which will not be described here.

[0140] The technical features of the above-described embodiments can be combined in any manner. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described, however, as long as the combinations of the technical features do not contradict each other, they should be considered within the scope of the present application.

[0141] The above-described embodiments only express several implementation manners of the present application, and the description is relatively specific and detailed, but it should not be understood as a limitation on the patent scope of the present application. It should be noted that for those skilled in the art, several modifications and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the patent protection scope of the present application should be subject to the appended claims.

Claims

1. A solar cell, characterized by, The solar cell comprises: a substrate having a first surface and a second surface arranged oppositely, the substrate having a second doping element; a first doping layer located on one side of the first surface; a first sub-diffusion layer located on one side of the first doping layer away from the substrate; a second sub-diffusion layer located on one side of the first sub-diffusion layer away from the substrate; wherein the first doping layer, the first sub-diffusion layer and the second sub-diffusion layer all have a first doping element, the first doping element being different from the second doping element in conductivity type; the doping concentration of the first doping element in the first sub-diffusion layer is less than the doping concentration of the first doping element in the second sub-diffusion layer; in a direction perpendicular to the plane in which the substrate lies, the thickness of the first sub-diffusion layer is less than or equal to half the thickness of the second sub-diffusion layer; the first sub-diffusion layer and the second sub-diffusion layer comprise silicon oxide.

2. The solar cell according to claim 1, wherein: a doping concentration of the first doped element in the first sub-diffusion layer is 4 x 10 19 cm -3 to 6 x 10 19 cm -3 ; and / or, The doping concentration of the first doping element in the second sub-diffusion layer is 0.8 x 10 21 cm -3 to 1.2 x 10 21 cm -3 .

3. The solar cell of claim 1, wherein in a direction perpendicular to the plane in which the substrate lies, the thickness of the first sub-diffusion layer is 20-30 nm; and / or the thickness of the second sub-diffusion layer is 60-80 nm.

4. The solar cell of claim 1, wherein the first doping layer is a first emitter layer; and / or the first doping layer comprises silicon and the first doping element doped in the silicon.

5. The solar cell of claim 1, wherein the first doping layer comprises a first tunneling oxide layer and a first doped polysilicon layer located on one side of the first tunneling oxide layer away from the substrate, the first doped polysilicon layer having the first doping element therein.

6. The solar cell according to claim 5, characterized in that, in a direction perpendicular to the plane in which the substrate lies, the thickness of the first tunneling oxide layer is 0.8-2 nm; and / or in a direction perpendicular to the plane in which the substrate lies, the thickness of the first doped polysilicon layer is 100-200 nm.

7. The solar cell of claim 5, wherein, a doping concentration of the first doping element in the first doped polysilicon layer is 2 x 10 20 cm -3 to 3 x 10 20 cm -3 .

8. The solar cell of claim 5, wherein, the first doping layer further comprises: a third diffusion sub-layer located between the first tunneling oxide layer and the substrate, the third diffusion sub-layer having the first doping element.

9. A method for manufacturing a solar cell, characterized by, The solar cell comprises: a substrate having a first surface and a second surface arranged oppositely, the substrate having a second doping element; forming a first doping layer on the first surface; forming a first sub-diffusion layer on one side of the first doping layer away from the substrate by a first deposition process, a doping source gas of a first doping element being provided at a first gas flow rate, a radio frequency power being a first radio frequency power, the first doping element being different from the second doping element in conductivity type, the first sub-diffusion layer comprising silicon oxide; forming a second sub-diffusion layer on one side of the first sub-diffusion layer away from the substrate by a second deposition process, the doping source gas of the first doping element being provided at a second gas flow rate, a radio frequency power being a second radio frequency power, wherein the first gas flow rate is less than the second gas flow rate, the first radio frequency power is less than the second radio frequency power; in a direction perpendicular to the plane in which the substrate lies, the thickness of the first sub-diffusion layer is less than or equal to half the thickness of the second sub-diffusion layer; the second sub-diffusion layer comprising silicon oxide.

10. The method of manufacturing a solar cell according to claim 9, wherein The step of forming the first doped layer on the first surface includes: forming a first emitter layer on the first surface of the substrate, the first doped layer being the first emitter layer.

11. The method of manufacturing a solar cell according to claim 9, wherein The step of forming the first doped layer on the first surface includes: forming a first tunneling oxide layer on one side of the first surface of the substrate, and forming a first doped polysilicon layer on a side of the first tunneling oxide layer away from the substrate, the first doped polysilicon layer having the first doped element therein.

12. A stacked battery characterized by comprising: The solar cell includes a top cell, a bonding layer and a bottom cell which are sequentially stacked, the bottom cell being the solar cell according to any one of claims 1 to 8.

13. A photovoltaic module, characterized by The solar cell includes: a cell string connected by a plurality of solar cells according to any one of claims 1 to 8, or connected by a plurality of solar cells manufactured by the manufacturing method of the solar cell according to any one of claims 9 to 11, or connected by the laminated cell according to claim 12; a connecting member for electrically connecting two adjacent solar cells; an encapsulation adhesive film for covering a surface of the cell string; a cover plate for covering a surface of the encapsulation adhesive film away from the cell string.

Images