Solar cell, photovoltaic module and photovoltaic system

Abstract

The invention relates to a solar cell, a photovoltaic module and a photovoltaic system. The solar cell includes: a substrate; the passivation contact layer is arranged on the first surface of the substrate, and the passivation contact layer comprises a first polycrystalline silicon doped conductive layer; wherein a doping element of the first polycrystalline silicon doped conductive layer is selected from at least one of an aluminum element, a gallium element, an indium element and a thallium element. According to the solar cell, the photovoltaic module and the photovoltaic system, the film forming quality of the polycrystalline silicon doped conducting layer is high, and the conversion efficiency of the solar cell is high.

Description

Technical Field

[0001] The present invention relates to the technical field of solar cells, and particularly to a solar cell, a photovoltaic module, and a photovoltaic system. Background Art

[0002] With the continuous development of photovoltaic technology, people's requirements for the photoelectric conversion efficiency of crystalline silicon solar cells are getting higher and higher. However, there are still many challenges in improving the efficiency of industrialized solar cells. In related art solar cells, a boron-doped polysilicon layer is formed on the front or back surface of the substrate of the solar cell to jointly form a PN junction or a high-low junction of PP+. In the case of forming a high-low junction of PP+ between the boron-doped polysilicon layer and the substrate, a tunneling oxide layer is further formed between the boron-doped polysilicon layer and the substrate to reduce the recombination of carriers. However, during the formation process of the boron-doped polysilicon layer, boron elements diffuse towards the substrate direction and remain in the tunneling oxide layer or the substrate, resulting in poor film formation quality of the polysilicon layer, thereby affecting the conversion efficiency of the solar cell. Summary of the Invention

[0003] Based on this, in view of the problem of poor film formation quality of the boron-doped polysilicon doped conductive layer, it is necessary to provide a solar cell, a photovoltaic module, and a photovoltaic system with a higher film formation quality of the polysilicon doped conductive layer and a higher conversion efficiency.

[0004] In the first aspect of the embodiments of the present application, a solar cell is provided, which includes:

[0005] A substrate; and

[0006] A passivation contact layer disposed on the first surface of the substrate, the passivation contact layer including a first polysilicon doped conductive layer;

[0007] Wherein, the doping element of the first polysilicon doped conductive layer is selected from at least one of aluminum element, gallium element, indium element, and thallium element.

[0008] In one embodiment, the doping element of the first polysilicon doped conductive layer is gallium element.

[0009] In one embodiment, the doping concentration of the gallium element is: 1×10 15 cm -3 1~1×10 22 cm -3 .

[0010] In one embodiment, the thickness of the first polysilicon doped conductive layer is: 0.1 nm to 100 nm.

[0011] In one embodiment, the passivation contact layer further includes a first tunneling oxide layer;

[0012] The first tunneling oxide layer is disposed on the first surface of the substrate, and the first polysilicon doped conductive layer is disposed on the surface of the first tunneling oxide layer facing away from the substrate.

[0013] In one embodiment, the first polysilicon doped conductive layer includes a metal contact region and a non-metal contact region disposed adjacent to each other;

[0014] The passivation contact layer further includes a conductive layer, the conductive layer is disposed on a side of the first polysilicon doped conductive layer facing away from the substrate, and at least covers the metal contact region of the first polysilicon doped conductive layer;

[0015] The solar cell further includes a first electrode, the first electrode is disposed on a side of the conductive layer facing away from the substrate, and the setting position of the first electrode corresponds to the metal contact region.

[0016] In one embodiment, the projection of the conductive layer on the first polysilicon doped conductive layer is located within the metal contact region.

[0017] In one embodiment, the conductive layer is configured as a boron-doped polysilicon layer.

[0018] In one embodiment, the passivation contact layer further includes a first barrier layer, the first barrier layer is disposed between the conductive layer and the first polysilicon doped conductive layer, and the first barrier layer is configured to be able to block the migration of boron elements in the conductive layer to the first polysilicon doped conductive layer.

[0019] In one embodiment, the first barrier layer is configured as a silicon dioxide layer.

[0020] In one embodiment, the thickness of the conductive layer is: 0.1 nm to 100 nm.

[0021] In one embodiment, the solar cell further includes a first functional layer;

[0022] The first functional layer includes at least two second polysilicon doped conductive layers, and each of the second polysilicon doped conductive layers is stacked on a side of the conductive layer facing away from the substrate;

[0023] The doping element of each of the second polysilicon doped conductive layers is selected from at least one of boron element, aluminum element, gallium element, indium element and thallium element.

[0024] In one embodiment, among at least two second polysilicon doped conductive layers, in each adjacent two second polysilicon doped conductive layers, the doping element of one of them is gallium element, and the doping element of the other is boron element.

[0025] In one embodiment, the first functional layer further includes at least one second barrier layer, and one second barrier layer is provided between every two adjacent second polysilicon doped conductive layers. Among every two adjacent second polysilicon doped conductive layers, the second barrier layer is configured to prevent the doping elements in the corresponding second polysilicon doped conductive layer farther from the substrate from migrating into the corresponding second polysilicon doped conductive layer closer to the substrate.

[0026] In one embodiment, the number of the second polysilicon doped conductive layers is less than or equal to 10; and / or

[0027] The thickness of the second polysilicon doped conductive layer is: 1 nm to 100 nm.

[0028] In one embodiment, among the second polysilicon doped conductive layers, the doping concentration of the second polysilicon doped conductive layer adjacent to the conductive layer is less than that of the other second polysilicon doped conductive layers.

[0029] In one embodiment, the substrate includes a second surface opposite to the first surface;

[0030] The solar cell further includes a second tunneling oxide layer and a third polysilicon doped conductive layer that are sequentially stacked on the second surface;

[0031] The doping element type of the third polysilicon doped conductive layer is the same as that of the substrate; the doping element type of the first polysilicon doped conductive layer is opposite to that of the substrate.

[0032] In the second aspect of the embodiments of the present application, a photovoltaic module is provided, including at least one battery string, and the battery string includes at least two of the above-mentioned solar cells.

[0033] In the third aspect of the embodiments of the present application, a photovoltaic system is provided, including the above-mentioned photovoltaic module.

[0034] Advantages of the above-mentioned solar cell, photovoltaic module and photovoltaic system:

[0035] Since the doping element of the first polysilicon doped conductive layer is selected from at least one of aluminum, gallium, indium and thallium, and the solid solubility of aluminum, gallium, indium and thallium is lower than that of boron, during the formation of the film layer of the first polysilicon doped conductive layer, the diffusion degree of aluminum, gallium, indium and thallium toward the substrate or into the adjacent film layer is small, or even no diffusion occurs. Compared with the polysilicon film layer doped with boron, the film formation quality of the first doped polysilicon conductive layer doped with at least one of aluminum, gallium, indium and thallium is improved, thereby also improving the conversion efficiency of the solar cell. Description of the Drawings

[0036] Figure 1 It is a schematic structural diagram of the solar cell provided by the embodiment of the present application;

[0037] Figure 2 It is a schematic diagram of another structure of the solar cell provided by the embodiment of the present application.

[0038] Explanation of the reference numerals in the drawings:

[0039] 100, solar cell;

[0040] 10, substrate;

[0041] 20, passivation contact layer; 21, first polysilicon doped conductive layer; 22, first barrier layer; 23, first tunneling oxide layer; 24, conductive layer;

[0042] 30, first functional layer; 31, second barrier layer; 32, second polysilicon doped conductive layer;

[0043] 40, second tunneling oxide layer;

[0044] 50, third polysilicon doped conductive layer;

[0045] 61, first electrode; 62, second electrode;

[0046] 71, first passivation film layer; 72, second passivation film layer;

[0047] F, first surface; S, second surface; A, metal contact area; B, non-metal contact area. Detailed implementation manners

[0048] To make the above objects, features and advantages of the present invention more obvious and understandable, the following will describe the detailed implementation manners of the present invention with reference to the accompanying drawings. Many specific details are set forth in the following description in order to fully understand the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

[0049] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present invention.

[0050] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present invention, the meaning of "a plurality of" is at least two, such as two, three, etc., unless otherwise specifically and clearly defined.

[0051] In the present invention, unless otherwise clearly specified and defined, the terms "mounted", "connected", "coupled", "fixed", etc. shall be construed in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the internal communication of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0052] In the present invention, unless otherwise clearly specified and defined, the first feature being "on" or "under" the second feature may be 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 being "above", "over" and "on top of" the second feature may be that the first feature is directly above or obliquely above the second feature, or merely indicates that the first feature has a higher horizontal height than the second feature. The first feature being "under", "beneath" and "underneath" the second feature may be that the first feature is directly below or obliquely below the second feature, or merely indicates that the first feature has a lower horizontal height than the second feature.

[0053] It should be noted that when an element is referred to as "fixed to" or "disposed on" another element, it can be directly on the other element or there can also be an intermediate element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intermediate element at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are only for illustrative purposes and do not represent the only implementation.

[0054] The solar cell, photovoltaic module and photovoltaic system according to the embodiments of the present application will be described below with reference to the accompanying drawings.

[0055] Figure 1 It is a schematic structural diagram of the solar cell provided by the embodiment of the present application, Figure 2 It is a schematic diagram of another structure of the solar cell provided by the embodiment of the present application.

[0056] Referring to Figure 1 、 Figure 2 In the first aspect of the embodiments of the present application, a solar cell 100 is provided, including a substrate 10 and a passivation contact layer 20. The passivation contact layer 20 is disposed on the first surface F of the substrate 10, and the passivation contact layer 20 includes a first polysilicon doped conductive layer 21. Wherein, the doping element of the first polysilicon doped conductive layer 21 is selected from at least one of aluminum element, gallium element, indium element and thallium element. Since the solid solubility of aluminum element, gallium element, indium element and thallium element is relatively low, lower than that of boron element, during the formation process of the film layer of the first polysilicon doped conductive layer 21, the diffusion degree of aluminum element, gallium element, indium element and thallium element towards the substrate 10 or into the adjacent film layer is relatively small, or even no diffusion occurs. Compared with the polysilicon film layer doped with boron element, the film formation quality of the first doped polysilicon conductive layer 21 doped with at least one of aluminum element, gallium element, indium element and thallium element is improved, thereby also improving the conversion efficiency of the solar cell 100.

[0057] It can be understood that the passivation contact layer 20 here can be used to jointly form a PN junction with the substrate 10, or can also be used to jointly form a high-low junction of PP+. In addition, in the embodiments of the present application, the TOPCon cell with the solar cell 100 as the back junction is taken as an example for illustration, but the type of the solar cell 100 is not limited thereto, and it can also be a battery such as a TBC cell including a passivation contact structure. In addition, it can also be applied to a front junction cell. The situation where the solar cell 100 is of other types is similar, and will not be elaborated here.

[0058] In the embodiments of the present application, the substrate 10 is, for example, an N-type substrate, and the passivation contact layer 20 is doped with P-type aluminum element, gallium element, indium element and thallium element to form a PN junction with the substrate 10.

[0059] The doping element of the first polysilicon doped conductive layer 21 is selected from at least one of aluminum, gallium, indium and thallium, which means that the doping element can be one of aluminum, gallium, indium and thallium. Alternatively, the doping element can be a combination of any two or three of aluminum, gallium, indium and thallium, or can include all four elements at the same time.

[0060] In the embodiment of the present application, the doping element of the first polysilicon doped conductive layer 21 is gallium. Since the solid solubility of gallium is lower than that of boron, the film quality of the first polysilicon doped conductive layer 21 can be optimized. In addition, gallium is a material with a good industrialization foundation in the semiconductor field, and its industrial chain is relatively complete and its manufacturing industrial system is sound.

[0061] In the embodiment of the present application, the doping concentration of gallium element is: 1×10 15 cm -3 1~1×10 22 cm -3 The concentration of gallium doping is set in this way, so that the energy band of the doped polysilicon in the first polysilicon doped conductive layer 21 is bent, which helps to reduce recombination.

[0062] In the embodiment of the present application, the thickness of the first polysilicon doped conductive layer 21 is 0.1 nm to 100 nm. This configuration makes the first polysilicon doped conductive layer 21 have a suitable thickness, which can ensure that the doped polysilicon energy band in the first polysilicon doped conductive layer 21 is bent, and helps to reduce recombination.

[0063] Continue to refer to Figure 1 , the passivation contact layer 20 further includes a first tunneling oxide layer 23. The first tunneling oxide layer 23 is disposed on the first surface F of the substrate 10, and the first polysilicon doped conductive layer 21 is disposed on the surface of the first tunneling oxide layer 23 away from the substrate 10. The first tunneling oxide layer 23 is used to achieve interface passivation of the first surface F of the substrate 10, and has a chemical passivation effect. Specifically, by saturating the dangling bonds on the surface of the substrate 10, the interface defect state density of the first surface F of the substrate 10 is reduced, thereby reducing the recombination center of the first surface F of the substrate 10 to reduce the carrier recombination rate.

[0064] Further, the first polysilicon doped conductive layer 21 includes a metal contact region A and a non-metal contact region B which are arranged adjacent to each other. Here, the metal contact region A refers to the region corresponding to the covering area of the following first electrode 61 on the side of the first surface F of the solar cell 100. The non-metal contact region B refers to the region on the first polysilicon conductive layer 24 except the metal contact region A. For example, the solar cell 100 further includes a first electrode 61, the first electrode 61 is disposed on the side of the conductive layer 24 away from the substrate 10, and the setting position of the first electrode 61 needs to correspond to the metal contact region A.

[0065] The passivation contact layer 20 further includes a conductive layer 24, the conductive layer 24 is disposed on the side of the first polysilicon doped conductive layer 21 away from the substrate 10, and at least covers the metal contact region A of the first polysilicon doped conductive layer 21. When the doping element used in the first polysilicon doped conductive layer 21 is selected from at least one of aluminum element, gallium element, indium element and thallium element, setting the conductive layer 24 on the side of the first polysilicon doped conductive layer 21 away from the substrate 10 can make up for the loss of conductivity brought by doping the above elements in the first polysilicon doped conductive layer 21, and make the conductivity better.

[0066] The conductive layer 24 at least covers the metal contact region A of the first polysilicon doped conductive layer 21. When specifically implemented, the conductive layer 24 can cover the first polysilicon doped conductive layer 21 entirely, or can also partially cover the first polysilicon doped conductive layer 21.

[0067] Exemplarily, the projection of the conductive layer 24 on the first polysilicon doped conductive layer 21 is located within the metal contact region A. In this way, the conductivity within the metal contact region A of the first polysilicon doped conductive layer 21 can be improved.

[0068] Further, the conductive layer 24 is configured as a boron-doped polysilicon layer. With such a setting, on the one hand, the conductivity within the metal contact region A of the first polysilicon doped conductive layer 21 can be improved. On the other hand, the effect of selective local passivation contact is also achieved.

[0069] Specifically, since the polysilicon film layer corresponding to the metal contact region A includes the first polysilicon doped conductive layer 21 and the boron-doped polysilicon layer, that is, the conductive layer 24, these two layers, and the polysilicon layer corresponding to the non-metal contact region B only includes the first polysilicon doped conductive layer 21, therefore, in the region of the passivation contact layer 20 corresponding to the metal contact region A, the thickness is greater than the thickness of the region corresponding to the non-metal contact region B. In other words, the thickness of the region of the passivation contact layer 20 corresponding to the metal contact region A is larger, which can effectively prevent the corrosion of the metal paste, improve the voltage and fill factor, and the thickness of the region of the passivation contact layer 20 corresponding to the non-metal contact region B is smaller, which can effectively reduce the absorption of light and improve the current, thereby improving the efficiency of the solar cell 100.

[0070] In the embodiment of the present application, the passivation contact layer 20 further includes a first barrier layer 22, and the first barrier layer 22 is disposed between the conductive layer 24 and the first polysilicon doped conductive layer 21. The first barrier layer 22 is configured to block the migration of boron elements in the conductive layer 24 to the first polysilicon doped conductive layer 21. In this way, the film forming quality of the first polysilicon doped conductive layer 21 can be further improved.

[0071] Specifically, the first barrier layer 22 is configured as a silicon dioxide layer. Or it can also be a film layer of other dielectric materials.

[0072] In addition, the thickness of the conductive layer 24 can be: 0.1 nm to 100 nm. When the conductive layer 24 is formed by an etching process, setting the thickness of the conductive layer 24 like this can ensure that it has a sufficient thickness to prevent the etching slurry from piercing through the conductive layer.

[0073] In the embodiment of the present application, referring to Figure 2 , the solar cell 100 further includes a first functional layer 30.

[0074] The first functional layer 30 includes at least two second polysilicon doped conductive layers 32, and the second polysilicon doped conductive layers 32 are stacked on the side of the conductive layer 24 away from the substrate 10.

[0075] The doping element of each second polysilicon doped conductive layer 32 is selected from at least one of boron element, aluminum element, gallium element, indium element and thallium element. Specifically, for each layer, the doping element can be one of aluminum element, gallium element, indium element and thallium element. Or the doping element can be a combination of any two or three of aluminum element, gallium element, indium element and thallium element, or can also include all four elements at the same time. Of course, for each second polysilicon doped conductive layer 32, the doping elements can be the same or different.

[0076] In a possible implementation manner, among the above-mentioned second polysilicon doped conductive layers 32, in each adjacent two second polysilicon doped conductive layers 32, the doping element of one of them is gallium element, and the doping element of the other is boron element.

[0077] The second polysilicon doped conductive layers 32 can be directly stacked to form the first functional layer 30, or a barrier layer can also be provided between adjacent second polysilicon doped conductive layers 32.

[0078] In specific implementation, the first functional layer 30 further includes at least one second barrier layer 31. One second barrier layer 31 is provided between every two adjacent second polysilicon doped conductive layers 32. Among every two adjacent second polysilicon doped conductive layers 32, the second barrier layer 31 is configured to block the migration of doping elements in the corresponding second polysilicon doped conductive layer 32 farther from the substrate 10 to the corresponding second polysilicon doped conductive layer 32 closer to the substrate 10. For example, when explaining with the up-and-down positional relationship shown in the drawing of Figure 2 , for each second barrier layer 31, the second barrier layer 31 is used to block the migration of doping elements in the second polysilicon doped conductive layer 32 adjacent to its lower side to the second polysilicon doped conductive layer 32 adjacent to its upper side. Figure 2 Taking the up-and-down positional relationship shown in the drawing as an example, for each second barrier layer 31, the second barrier layer 31 is used to block the migration of doping elements in the second polysilicon doped conductive layer 32 adjacent to its lower side to the second polysilicon doped conductive layer 32 adjacent to its upper side.

[0079] Furthermore, the number of layers of the second polysilicon doped conductive layer 32 is less than or equal to 10. In addition, the thickness of the second polysilicon doped conductive layer 32 is: 1 nm to 100 nm.

[0080] It can be understood that the first functional layer 30 is disposed on the conductive layer 24. When the projection of the conductive layer 24 on the first polysilicon doped conductive layer 21 is located within the metal contact region A, the first functional layer 30 also corresponds to the metal contact region A. In this way, the thickness of the film layer deposited on the metal contact region A is further greater than the thickness of the film layer deposited on the surface of the non-metal contact region B, so as to achieve a better local selective passivation effect.

[0081] Furthermore, among the second polysilicon doped conductive layers 32, the doping concentration of the second polysilicon doped conductive layer 32 adjacent to the conductive layer 24 is less than that of the remaining second polysilicon doped conductive layers 32. That is, except for the second polysilicon doped conductive layer 32 adjacent to the conductive layer 24, the remaining second polysilicon doped conductive layers 32 are all heavily doped layers, and the doping concentration distribution shows a stepped shape.

[0082] In the embodiment of the present application, continue to refer to Figure 2 , the substrate 10 includes a second surface S opposite to the first surface F. The solar cell 100 further includes a second tunneling oxide layer 40 and a third polysilicon doped conductive layer 50 sequentially stacked on the second surface S. The third polysilicon doped conductive layer 50 may be doped with an N-type element, for example, doped with phosphorus.

[0083] The doping element type of the third polysilicon doped conductive layer 50 is the same as that of the substrate 10, and the doping element type of the first polysilicon doped conductive layer 21 is opposite to that of the substrate 10.

[0084] Furthermore, the solar cell 100 further includes a first passivation film layer 71, a second passivation film layer 72, and a second electrode 62.

[0085] The first passivation film layer 71 is stacked on the surface of the first functional layer 30 facing away from the substrate 10, that is, on one side (back side) of the first surface F of the substrate 10. The first passivation film layer 71 can adopt a single-layer or multi-layer structure, and the material of the first passivation film layer 71 can be silicon oxide, silicon nitride or silicon oxynitride. For example, the first passivation film layer 71 can include at least one first antireflection layer (not shown). In this way, the reflectivity of the back surface of the solar cell 100 to sunlight can be reduced, and the absorption rate of the back surface of the solar cell 100 to sunlight can be increased. Therefore, the first passivation film layer 71 plays both a passivation and an antireflection role.

[0086] The second passivation film layer 72 is stacked on the surface of the third polysilicon doped conductive layer 50 facing away from the substrate 10. The second passivation film layer 72 plays a surface passivation role and an antireflection role in the solar cell 100, can perform good chemical passivation on the dangling bonds on the surface of the substrate 10, and has an antireflection effect on the front surface of the solar cell 100.

[0087] Exemplarily, the second passivation film layer 72 can include at least one second antireflection layer (not shown).

[0088] The second antireflection layer is located on one side of the second surface S of the solar cell 100 to achieve an antireflection effect. The second antireflection layer can adopt a multi-layer structure. In the multi-layer second antireflection layer, the materials of each layer can be silicon oxide, silicon nitride or silicon oxynitride.

[0089] In addition, the first electrode 61 is disposed on the first passivation film layer 71 and connected to the first functional layer 30, and the second electrode 62 is disposed on the second passivation film layer 72 and connected to the third polysilicon doped conductive layer 50.

[0090] In the second aspect of the embodiments of the present application, a photovoltaic module (not shown) is further provided.

[0091] The photovoltaic module includes at least one battery string, and the battery string includes at least two solar cells 100 as described above. Each solar cell 100 can be connected together by string soldering.

[0092] In the third aspect of the embodiments of the present application, a photovoltaic system (not shown) is further provided.

[0093] The photovoltaic system includes the above-mentioned photovoltaic modules. The photovoltaic system can be applied in photovoltaic power stations, such as ground power stations, rooftop power stations, water surface power stations, etc., and can also be applied to devices or apparatuses that generate electricity using solar energy, such as user solar power supplies, solar street lamps, solar cars, solar buildings, and so on. Of course, it can be understood that the application scenarios of the photovoltaic system are not limited to this, that is to say, the photovoltaic system can be applied in all fields that require solar power generation. Taking the photovoltaic power generation system network as an example, the photovoltaic system can include a photovoltaic array, a busbar box, and an inverter. The photovoltaic array can be an array combination of multiple photovoltaic modules. For example, multiple photovoltaic modules can form multiple photovoltaic arrays. The photovoltaic array is connected to the busbar box, and the busbar box can converge the current generated by the photovoltaic array. The converged current flows through the inverter and is converted into alternating current required by the commercial power grid and then connected to the commercial power grid to achieve solar power supply.

[0094] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0095] The above-described embodiments merely represent several implementation manners of the present invention, and the description thereof is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the invention patent shall be subject to the appended claims.

Claims

1. A solar cell, characterized in that, The solar cell includes: a substrate; and a passivation contact layer disposed on a first surface of the substrate, the passivation contact layer including a first polysilicon doped conductive layer; wherein, the doping element of the first polysilicon doped conductive layer is selected from at least one of aluminum, gallium, indium, and thallium.

2. The solar cell according to claim 1, wherein The doping element of the first polysilicon doped conductive layer is gallium.

3. The solar cell according to claim 2, characterized in that, The doping concentration of the gallium element is: 1×10 15 cm -3 1 to 1×10 22 cm -3 .

4. The solar cell according to claim 2, wherein, The thickness of the first polysilicon doped conductive layer is: 0.1 nm to 100 nm.

5. The solar cell according to claim 1, characterized in that, The passivation contact layer further includes a first tunneling oxide layer; The first tunneling oxide layer is disposed on the first surface of the substrate, and the first polysilicon doped conductive layer is disposed on a surface of the first tunneling oxide layer facing away from the substrate.

6. The solar cell according to claim 1, characterized in that, The first polysilicon doped conductive layer includes a metal contact region and a non-metal contact region arranged adjacent to each other; The passivation contact layer further includes a conductive layer, the conductive layer is disposed on a side of the first polysilicon doped conductive layer facing away from the substrate, and at least covers the metal contact region of the first polysilicon doped conductive layer; The solar cell further includes a first electrode, the first electrode is disposed on a side of the conductive layer facing away from the substrate, and the setting position of the first electrode corresponds to the metal contact region.

7. The solar cell according to claim 6, wherein, The projection of the conductive layer on the first polysilicon doped conductive layer is located within the metal contact region.

8. The solar cell according to claim 6, characterized in that, The conductive layer is configured as a boron-doped polysilicon layer.

9. The solar cell according to claim 8, characterized in that, The passivation contact layer further includes a first barrier layer, the first barrier layer is disposed between the conductive layer and the first polysilicon doped conductive layer, and the first barrier layer is configured to block the migration of boron elements in the conductive layer to the first polysilicon doped conductive layer.

10. The solar cell according to claim 9, characterized in that, The first barrier layer is configured as a silicon dioxide layer.

11. The solar cell according to claim 8, wherein, The thickness of the conductive layer is: 10 nm to 200 nm.

12. The solar cell according to claim 6, characterized in that, The solar cell further includes a first functional layer; The first functional layer includes at least two second polysilicon doped conductive layers, and each of the second polysilicon doped conductive layers is stacked on a side of the conductive layer facing away from the substrate; The doping element of each of the second polysilicon doped conductive layers is selected from at least one of boron, aluminum, gallium, indium, and thallium.

13. The solar cell according to claim 12, wherein, Among the at least two second polysilicon doped conductive layers, in each adjacent two of the second polysilicon doped conductive layers, the doping element of one of them is gallium, and the doping element of the other is boron.

14. The solar cell according to claim 12, wherein, The first functional layer further includes at least one second barrier layer, and one second barrier layer is provided between each adjacent two of the second polysilicon doped conductive layers. In each adjacent two of the second polysilicon doped conductive layers, the second barrier layer is configured to block the migration of the doping element in the corresponding second polysilicon doped conductive layer farther from the substrate to the corresponding second polysilicon doped conductive layer closer to the substrate.

15. The solar cell according to claim 12, wherein The number of layers of the second polysilicon doped conductive layer is less than or equal to 10; and / or The thickness of the second polysilicon doped conductive layer is: 1 nm to 100 nm.

16. The solar cell according to claim 12, characterized in that, In each of the second polysilicon doped conductive layers, the doping concentration of the second polysilicon doped conductive layer adjacent to the conductive layer is less than that of the remaining second polysilicon doped conductive layers.

17. The solar cell according to any one of claims 1-16, characterized in that, The substrate includes a second surface disposed opposite to the first surface; The solar cell further includes a second tunneling oxide layer and a third polysilicon doped conductive layer sequentially stacked on the second surface; The doping element type of the third polysilicon doped conductive layer is the same as that of the substrate; the doping element type of the first polysilicon doped conductive layer is opposite to that of the substrate.

18. A photovoltaic module, characterized in that, It includes at least one battery string, and the battery string includes at least two solar cells as described in any one of claims 1-17.

19. A photovoltaic system, characterized in that, It includes a photovoltaic module as described in claim 18.

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