TOPCon solar cell and photovoltaic module

Abstract

The utility model provides a TOPCon solar cell and a photovoltaic module, and the TOPCon solar cell comprises an N-type silicon substrate which comprises a front surface and a back surface; the boron-gallium co-doped layer is positioned on the front surface; the first laminated passivation structure is positioned on the surface, far away from the N-type silicon substrate, of the boron-gallium co-doped layer; the first electrode is located on the surface, away from the boron-gallium co-doped layer, of the first laminated passivation structure; a second stack passivation structure on the back surface; and the second electrode is positioned on the surface, far away from the N-type silicon substrate, of the second laminated passivation structure.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of solar cells, in particular to a TOPCon solar cell and a photovoltaic module. BACKGROUND

[0002] In the process of front-side boron doping of a conventional TOPCon solar cell, B-O complexes are easily formed, which reduces the number of minority carriers in the material diffusion, thereby causing the open-circuit voltage of the solar cell to decrease and the photovoltaic module to decay too quickly. This problem seriously affects the photoelectric conversion efficiency and long-term stability of the solar cell, and limits the further application and development of the TOPCon solar cell. CONTENT OF THE UTILITY MODEL

[0003] The main purpose of the present application is to provide a TOPCon solar cell and a photovoltaic module to at least solve the problem of low photoelectric conversion efficiency of the TOPCon solar cell in the prior art.

[0004] In order to achieve the above-mentioned purpose, according to one aspect of the present application, a TOPCon solar cell is provided, comprising: an N-type silicon substrate comprising a front side and a back side; a boron-gallium co-doped layer located on the front side; a first laminated passivation structure located on the surface of the boron-gallium co-doped layer away from the N-type silicon substrate; a first electrode located on the surface of the first laminated passivation structure away from the boron-gallium co-doped layer; a second laminated passivation structure located on the back side; and a second electrode located on the surface of the second laminated passivation structure away from the N-type silicon substrate.

[0005] Optionally, the thickness of the boron-gallium co-doped layer is 0.5-1.5pm.

[0006] Optionally, the first laminated passivation structure comprises: a first passivation layer located on the surface of the boron-gallium co-doped layer away from the N-type silicon substrate; and a second passivation layer located on the surface of the first passivation layer away from the boron-gallium co-doped layer.

[0007] Optionally, the first passivation layer is a silicon oxide layer, the second passivation layer is a silicon oxynitride layer, and the total thickness of the first passivation layer and the second passivation layer is 65-90pm.

[0008] Optionally, the second laminated passivation structure comprises: a tunneling layer located on the back side; a doped polysilicon layer located on the surface of the tunneling layer away from the N-type silicon substrate; and a third passivation layer located on the surface of the doped polysilicon layer away from the tunneling layer.

[0009] Optionally, the thickness of the tunneling layer is 0.5-1.5nm, and the thickness of the doped polysilicon layer is 60-180nm.

[0010] Optionally, the tunneling layer is a silicon oxide layer, and the third passivation layer comprises a silicon oxide layer and a silicon oxynitride layer stacked in a direction away from the doped polysilicon layer.

[0011] Optionally, the thickness of the third passivation layer is 65-90 microns.

[0012] Optionally, at least one of the front surface and the back surface has a pyramid-shaped anti-reflection texture structure.

[0013] According to another aspect of the present application, a photovoltaic module is provided, comprising any one of the TOPCon solar cells.

[0014] By applying the technical solution of the present application, a boron-gallium co-doped layer is arranged on the N-type silicon substrate, and the two form a PN junction. Since the atomic radius of gallium in the boron-gallium co-doped layer is large, the formation of the B-Ga co-doped PN junction metastable state B-O complex can be hindered, thereby reducing the interface recombination, improving the open-circuit voltage and short-circuit current of the TOPCon solar cell, and reducing the light-induced degradation. BRIEF DESCRIPTION OF DRAWINGS

[0015] The drawings accompanying the specification of the present application serve to provide a further understanding of the present application, and the illustrative embodiments of the present application and their descriptions serve to explain the present application, and do not constitute improper limitations on the present application. In the drawings:

[0016] Figure 1 A structural schematic diagram of a TOPCon solar cell according to an embodiment of the present application is shown;

[0017] Figure 2 Another schematic diagram of a TOPCon solar cell according to an embodiment of the present application is shown;

[0018] Figure 3 A scanning electron microscope image of a pyramid-shaped anti-reflection texture in a TOPCon solar cell according to an embodiment of the present application is shown;

[0019] Figure 4 A schematic diagram of a double-air-pipe diffusion furnace according to an embodiment of the present application is shown;

[0020] Figure 5 A structural schematic diagram of a photovoltaic module according to an embodiment of the present application is shown;

[0021] Figure 6 A comparison diagram of the electrical conversion efficiency degradation rate of a boron-doped, B-Ga co-doped photovoltaic module according to an embodiment of the present application is shown.

[0022] Among the above drawings, the following reference signs are included:

[0023] 10, N-type silicon substrate; 12, boron-gallium co-doped layer; 14, first stacked passivation structure; 16, first electrode; 18, second stacked passivation structure; 20, second electrode; 22, first passivation layer; 24, second passivation layer; 26, tunneling layer; 28, doped polysilicon layer; 30, third passivation layer; 32, pyramid-shaped anti-reflective texture; 34, TOPCon solar cell; 36, encapsulation layer; 38, cover plate; 40, conductive ribbon. DETAILED DESCRIPTION

[0024] It should be noted that the following detailed description is exemplary in nature and is intended to provide further description of the application. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

[0025] It is also important to note that the terms "including", "comprising", and / or "having" as used herein are specifically intended to be open-ended and also to mean including, avoiding the exclusion of, e.g., additional, non-specified elements or steps. Rather, "including", "comprising", and / or "having" will be considered and interpreted to be equivalent to the term "consisting of" to the same extent as "consisting of" is interpreted in the Doha Accord or in 35 U.S.C. § 112, paragraph 6.

[0026] It is understood that when an element such as a layer, film, region, or substrate is referred to as being "on" another element, it can be directly on the other element or intervening elements can also be present. In addition, it is understood that when an element is referred to as being "connected" to or "coupled" to another element, it can be directly connected or coupled to the other element or intervening elements can also be present.

[0027] As introduced in the background, the photoelectric conversion efficiency of the prior art TOPCon solar cell is low, in order to solve the above technical problems, the application provides a TOPCon solar cell and a photovoltaic module.

[0028] The principles and configuration of the present application will be described in detail below with reference to the accompanying drawings of the embodiments of the present application.

[0029] The embodiments of the present application provide a TOPCon solar cell, Figure 1 An exemplary structure diagram of a TOPCon solar cell of the present application is shown as follows. Figure 1 As shown in the figure, the TOPCon solar cell comprises:

[0030] An N-type silicon substrate 10 comprising a front surface and a back surface;

[0031] Specifically, the N-type silicon substrate 10 is used to receive incident light and generate photo-generated carriers. The N-type silicon substrate 10 is doped with N-type ions, which can be any one of phosphorus, arsenic or antimony. The front surface of the N-type silicon substrate 10 is opposite to the back surface.

[0032] A boron-gallium co-doped layer 12 is located on the front surface.

[0033] Specifically, the boron-gallium co-doped layer 12 is a conductive layer doped with boron ions and gallium ions. The boron-gallium co-doped layer 12 is a P-type conductive layer, which forms a PN junction with the N-type silicon substrate 10.

[0034] A first stacked passivation structure 14 is located on the surface of the boron-gallium co-doped layer 12 away from the N-type silicon substrate 10.

[0035] Specifically, the first stacked passivation structure 14 is a multi-layer film structure that plays a passivation role.

[0036] A first electrode 16 is located on the surface of the first stacked passivation structure 14 away from the boron-gallium co-doped layer 12.

[0037] Specifically, the first electrode 16 can penetrate the first stacked passivation structure 14 and form an electrical connection with the boron-gallium co-doped layer 12.

[0038] A second stacked passivation structure 18 is located on the back surface.

[0039] Specifically, the second stacked passivation structure 18 is a multi-layer film structure that plays a passivation role.

[0040] A second electrode 20 is located on the surface of the second stacked passivation structure 18 away from the N-type silicon substrate 10.

[0041] In the embodiments, a boron-gallium co-doped layer is arranged on the N-type silicon substrate, and the two form a PN junction. Since the atomic radius of gallium in the boron-gallium co-doped layer is large, the formation of the PN junction metastable B-O complex can be hindered, thereby reducing the interface recombination of the TOPCon solar cell, improving the open-circuit voltage and short-circuit current of the TOPCon solar cell, reducing the light-induced decay, and achieving the improvement of the photoelectric conversion efficiency.

[0042] In some embodiments, the TOPCon solar cell is a single-sided cell, that is, only the front surface of the N-type silicon substrate is used to receive solar light. In some embodiments, the TOPCon solar cell is a double-sided cell, that is, the front surface and the back surface of the N-type silicon substrate are used to receive solar light. In some embodiments, the material of the N-type silicon substrate can include single crystal silicon, polycrystalline silicon, amorphous silicon and microcrystalline silicon, etc.

[0043] In some embodiments, the material of the first electrode is an electrically conductive material, which can specifically include at least one of silver, aluminum, copper, tin, gold, lead or nickel.

[0044] In some embodiments, the material of the second electrode is an electrically conductive material, which can specifically include at least one of silver, aluminum, copper, tin, gold, lead or nickel.

[0045] In an optional solution, the thickness of the boron-gallium co-doped layer is 0.5-1.5 μm. For example, the thickness of the boron-gallium co-doped layer can be 0.5 μm, 0.8 μm, 1.0 μm, 1.2 μm or 1.5 μm, etc. In the embodiments, the thickness range of the boron-gallium co-doped layer not only ensures that the boron and gallium elements can be effectively doped into the silicon wafer to form a stable co-doped structure, but also avoids the problems of increased carrier recombination, increased series resistance and increased optical loss, etc. caused by excessive thickness, thereby reducing the performance and cost of the TOPCon solar cell.

[0046] Specifically, the process method for forming the first stacked passivation structure can include thermal oxidation, chemical vapor deposition (CVD method), atomic layer deposition (ALD method), wet chemical method, physical vapor deposition (PVD) method, etc.

[0047] Specifically, the process method for forming the second stacked passivation structure can include thermal oxidation, chemical vapor deposition (CVD method), atomic layer deposition (ALD method), wet chemical method, physical vapor deposition (PVD) method, etc.

[0048] In another optional solution, as shown in FIG. 2, the first stacked passivation structure 14 includes: Figure 2

[0049] The first passivation layer 22 is located on the surface of the boron-gallium co-doped layer 12 away from the N-type silicon substrate 10.

[0050] The second passivation layer 24 is located on the surface of the first passivation layer 22 away from the boron-gallium co-doped layer 12.

[0051] In the embodiments, by introducing the multi-layer passivation structure, the interface recombination rate is significantly reduced, the loss of photo-generated carriers is reduced, the open-circuit voltage and short-circuit current are improved, the photoelectric conversion efficiency is improved, and the light-induced degradation is further reduced.

[0052] Specifically, the material of the first passivation layer can be one or more of silicon oxide, aluminum oxide, silicon nitride, silicon oxynitride, carbon-doped silicon nitride or silicon oxynitride. The process method for forming the first passivation layer can include but is not limited to thermal oxidation, chemical vapor deposition (CVD method), atomic layer deposition (ALD method), wet chemical method, physical vapor deposition (PVD) method, etc. ​

[0053] Specifically, the material of the second passivation layer can be one or more of silicon oxide, aluminum oxide, silicon nitride, silicon oxynitride, carbon-doped silicon nitride, or silicon oxynitride. The process methods for forming the second passivation layer can include, but are not limited to, thermal oxidation, chemical vapor deposition (CVD), atomic layer deposition (ALD), wet chemical deposition, and physical vapor deposition (PVD).

[0054] In other exemplary embodiments, the first passivation layer is a silicon oxide layer, and the second passivation layer is a silicon oxynitride layer, with a total thickness of 65–90 μm. For example, the total thickness of the first and second passivation layers can be 65 μm, 70 μm, 88 μm, or 90 μm, etc. In this embodiment, while further ensuring the passivation effect, by setting the stacked silicon oxide and silicon oxynitride layers and controlling their total thickness to be 65–90 μm, the light absorption and light reflection capabilities of the substrate can be adjusted, thereby improving the short-circuit current of the battery. In addition, the silicon-containing material in the silicon oxide and silicon oxynitride layers is synthesized from silanes, and the hydrogen content therein can improve the open-circuit voltage of the battery.

[0055] Furthermore, the refractive index of the first stacked passivation structure composed of the silicon oxide layer and the silicon oxynitride layer can be 2 to 2.25. For example, the refractive index of the first stacked passivation structure can be 2, 2.1, 2.15, 2.2, or 2.25, etc.

[0056] In another alternative, such as Figure 2 As shown, the second stacked passivation structure 18 includes:

[0057] Tunnel layer 26 is located on the back side;

[0058] A doped polycrystalline silicon layer 28 is located on the surface of the tunneling layer 26 away from the N-type silicon substrate 10;

[0059] The third passivation layer 30 is located on the surface of the doped polysilicon layer 28 away from the tunneling layer 26.

[0060] In the embodiment described, the tunneling layer is used to achieve interface passivation on the back side of the N-type silicon substrate; the doped polycrystalline silicon layer, located above the tunneling layer, forms a field passivation layer, which can further optimize the back electric field of the cell, reduce recombination losses, and thus improve carrier collection efficiency, further enhancing the open-circuit voltage and short-circuit current of the TOPCon solar cell; the third passivation layer, located above the doped polycrystalline silicon layer, provides additional passivation, reduces recombination centers on the back side, further reduces light-induced degradation of the cell, and improves the long-term stability and reliability of the cell. Simultaneously, the third passivation layer can also protect the doped polycrystalline silicon layer from external environmental influences, extending the cell's lifespan.

[0061] In some embodiments, the second electrode can penetrate the third passivation layer to form an electrical connection with the doped polysilicon layer.

[0062] In some embodiments, the material of the tunneling layer can be a dielectric material, such as silicon oxide. A person skilled in the art can form the tunneling layer by using a deposition process, such as a chemical vapor deposition process. In other embodiments, the tunneling layer can also be formed by using an in-situ generation process.

[0063] Specifically, the tunneling layer can cause an asymmetric shift in the energy band of the back surface, such that the potential barrier for the majority carriers is lower than that for the minority carriers. Therefore, the majority carriers can more easily quantum tunnel through the tunneling layer, while the minority carriers are difficult to pass through the tunneling layer, so as to achieve selective transmission of the carriers. In addition, the tunneling layer can also have a chemical passivation effect on the substrate.

[0064] In some embodiments, the doped polysilicon layer has the same type of doping elements as the N-type silicon substrate, and the doped polysilicon layer can include one or more of N-type doped polysilicon, N-type doped microcrystalline silicon, or N-type doped amorphous silicon.

[0065] Specifically, the material of the third passivation layer can be one or more of silicon oxide, aluminum oxide, silicon nitride, silicon oxynitride, carbon-doped silicon nitride, or silicon oxynitride. In some embodiments, the third passivation layer can be a single-layer structure. In other embodiments, the third passivation layer can also be a multi-layer structure.

[0066] In some embodiments, the doped polysilicon layer can have the same type of doping ions as the N-type silicon substrate.

[0067] In some embodiments, the third passivation layer can reduce the reflection of incident light by the N-type silicon substrate.

[0068] In some example embodiments of the present application, the thickness of the tunneling layer is 0.5-1.5 nm, and the thickness of the doped polysilicon layer is 60-180 nm. For example, the thickness of the tunneling layer can be 0.5 nm, 0.7 nm, 1.0 nm, or 1.5 nm, etc., and the thickness of the doped polysilicon layer can be 60 nm, 70 nm, 85 nm, 90 nm, 130 nm, or 180 nm, etc. In the embodiments, controlling the thickness of the tunneling layer within the range of 0.5-1.5 nm can ensure that the electrons can effectively tunnel through, while blocking the recombination of holes; and controlling the thickness of the doped polysilicon layer within the range of 60-180 nm can ensure sufficient carrier collection capability, while avoiding excessive layer thickness leading to increased resistance; by optimizing the thickness of the tunneling layer and the doped polysilicon layer, the present application can reduce interface recombination loss, improve carrier collection efficiency, and further reduce photo-induced decay.

[0069] In some optional embodiments of the present application, the tunneling layer is a silicon oxide layer, and the third passivation layer includes a silicon oxide layer and a silicon oxynitride layer stacked in a direction away from the doped polysilicon layer. The silicon oxide layer serves as a channel for electron tunneling and blocks hole recombination, and can further reduce interface recombination loss, while the stacked silicon oxide layer and silicon oxynitride layer can adjust the light absorption and light reflection capabilities of the substrate, thereby improving the short-circuit current of the cell; in addition, the silicon-containing substances in the silicon oxide layer and the silicon oxynitride layer are synthesized by silane, and the hydrogen content therein can improve the open-circuit voltage of the cell.

[0070] In some optional embodiments of the present application, the thickness of the third passivation layer is 65-90 μm. For example, the total thickness of the third passivation layer can be 65 μm, 72 μm, 85 μm, or 90 μm, etc. Within this thickness range, the third passivation layer can effectively cover the back surface of the solar cell, reduce the carrier recombination loss on the back surface, and reduce the dangling bonds and defects on the back surface, so that more electrons and holes can be effectively separated and transported within the cell, thereby improving the photoelectric conversion efficiency of the cell; at the same time, the passivation layer within this range will not significantly affect the light transmittance, thereby helping to reduce photo-induced decay.

[0071] According to some optional embodiments of the present application, at least one of the front surface and the back surface has a pyramid-shaped anti-reflection textured structure. In the embodiments, the textured structure can increase the reflectivity of the surface of the solar cell, reduce the reflection loss of light, and improve the light absorption rate. In addition, the textured structure can also increase the scattering of light, prolong the propagation path of light within the cell, increase the interaction between light and material, and improve the light energy conversion efficiency. Therefore, the textured structure plays an important role in the solar cell, and can improve the power generation efficiency and performance of the solar cell.

[0072] In some embodiments, the front side of the N-type silicon substrate can be configured as a pyramid-shaped anti-reflective textured surface to reduce the reflectivity of the front side of the N-type silicon substrate to incident light, thereby increasing the light absorption and utilization rate.

[0073] In some embodiments, the back side of the N-type silicon substrate can be configured as a pyramid-shaped anti-reflective textured surface to reduce the reflectivity of the back side of the N-type silicon substrate to incident light, thereby increasing the absorption and utilization rate of light.

[0074] In some embodiments, the front side of the N-type silicon substrate can be configured as a non-pyramidal textured surface, such as a stacked stepped morphology, so that the boron-gallium co-doped layer on the front side of the N-type silicon substrate has high density and uniformity.

[0075] In some embodiments, the back side of the N-type silicon substrate can be configured as a non-pyramidal textured surface, such as a stacked stepped morphology, so that the tunneling layer on the back side of the N-type silicon substrate has high density and uniformity, and the tunneling layer has a good passivation effect on the back side of the N-type silicon substrate.

[0076] like Figure 3 As shown, the pyramid-shaped anti-reflective surface 32 includes a bottom surface and three inclined surfaces connected to the bottom surface, with the three inclined surfaces connected to each other to form a tetrahedral structure. At least a portion of the surface of at least one inclined surface of the pyramid-shaped anti-reflective surface is concave or convex relative to the center of the pyramid-shaped anti-reflective surface; that is, at least one inclined surface of the pyramid-shaped anti-reflective surface has irregular deformation. For example, one inclined surface of the pyramid-shaped anti-reflective surface may be concave only relative to the center of the pyramid-shaped anti-reflective surface, or convex only relative to the center of the pyramid-shaped anti-reflective surface, or a portion of the inclined surface may be concave relative to the center of the pyramid-shaped anti-reflective surface, while another portion may be convex relative to the center of the pyramid-shaped anti-reflective surface. In some embodiments, only one inclined surface of the pyramid-shaped anti-reflective surface may have irregular deformation; in other embodiments, two inclined surfaces may have irregular deformation; and in still other embodiments, all three inclined surfaces may have irregular deformation. Furthermore, in some other embodiments, at least a portion of the bottom surface of the pyramid-shaped antireflective velvet is recessed or protruding relative to the center of the pyramid-shaped antireflective velvet, meaning that the bottom surface of the pyramid-shaped antireflective velvet also has irregular deformation.

[0077] For example, such as Figure 4 As shown, this application provides a method for preparing a boron-gallium co-doped structure, comprising the following steps:

[0078] Step 1: Add a GaCl3 inlet pipe to the inlet end of the diffusion furnace tube, thereby transforming the single diffusion source of BCl3 into a dual diffusion source of BCl3 and GaCl3.

[0079] Step two: N2 is used to carry BCl3 and GaCl3 respectively into the diffusion furnace tube where N-type silicon substrate is placed, and parameters such as diffusion source temperature, gas passing time and diffusion temperature are controlled to form the boron-gallium co-doped layer on the surface of the N-type silicon substrate. Figure 4 The temperature measuring thermocouple in the diffusion furnace tube is used to regulate the diffusion temperature of the gas in the diffusion furnace tube.

[0080] Experiments have verified that boron-gallium double metal doping has no obvious adverse effect on the EL (Electroluminescence) of the battery, and compared with the boron-doped solar cell, the boron-gallium double metal doping improves the open-circuit voltage, current density and photoelectric conversion efficiency of the battery.

[0081] The embodiments of the present application also provide a photovoltaic module, which comprises any one of the TOPCon solar cells.

[0082] In the embodiments, the photovoltaic module comprises the TOPCon solar cell, which is provided with a boron-gallium co-doped layer on an N-type silicon substrate, and the two form a PN junction. Since the atomic radius of gallium in the boron-gallium co-doped layer is large, the formation of the PN junction metastable B-O complex can be hindered, thereby reducing the interface recombination of the TOPCon solar cell, improving the open-circuit voltage and short-circuit current of the photovoltaic module, reducing the light-induced degradation, and improving the photoelectric conversion capability and efficiency of the photovoltaic module.

[0083] In an example embodiment, as shown in Figure 5 The photovoltaic module comprises a battery string, the battery string is connected by a plurality of TOPCon solar cells 34 provided by the embodiments; an encapsulation layer 36 is used to cover the surface of the battery string; and a cover plate 38 is used to cover the surface of the encapsulation layer away from the battery string. The solar cells are electrically connected in the form of a whole piece or multiple pieces to form a plurality of battery strings, and the plurality of battery strings are electrically connected in series and / or parallel. Specifically, in some embodiments, the plurality of battery strings can be electrically connected by a conductive band 40. The encapsulation layer covers the first surface and the second surface of the solar cell, and specifically, the encapsulation layer can be an organic encapsulation film such as an ethylene-vinyl acetate copolymer film, a polyethylene octene elastomer film or a polyethylene terephthalate film. In some embodiments, the cover plate can be a glass cover plate, a plastic cover plate or a cover plate with a light transmission function. Specifically, the surface of the cover plate facing the encapsulation layer can be a concave-convex surface, thereby increasing the utilization rate of incident light.

[0084] Exemplarily, the texturing wafer is subjected to boron oxide and gallium oxide deposition in a BCl3 and GaCl3 double-tube diffusion furnace after modification, and then is subjected to oxidation promotion, and the remaining processes are performed by using the production line process, and the process continues to be tracked to printing, and the printed solar cell is subjected to photoelectric conversion efficiency test and grading. Further, the main stream grade battery piece is selected, and the light soaking test is performed at 1000W / cm 2 The light soaking treatment is performed for 24h, and the photoelectric conversion efficiency of the battery piece is tested during the light soaking to evaluate the light-induced degradation of the solar cell.

[0085] Exemplarily, the open-circuit voltage of the boron-gallium co-doped battery is increased by 1-2mV, the short-circuit current is increased by 5mA, and the efficiency is increased by 0.06-0.15%, and it has been verified that there is no negative impact on the yield. The boron-doped and boron-gallium co-doped battery is assembled into a module, and the light soaking test is performed at 1000W / cm 2 . As shown in Figure 6 , the battery degradation rate is 0.93% after 13h, and the degradation rate tends to be stable thereafter. The degradation rate of the boron-doped main stream photovoltaic module is 1.95% after 24h, and it still shows a continuous upward trend as the light soaking time increases.

[0086] Specifically, compared with the photovoltaic module composed of the solar cell with a boron-doped layer, the open-circuit voltage of the photovoltaic module of the present application is increased by 1-2mV, the short-circuit current is increased by 5mA, and the photoelectric conversion efficiency is increased by 0.06-0.15%, and it has been verified that the boron-gallium co-doping step has no negative impact on the yield of the TOPCon solar cell.

[0087] The boron-doped solar cell and the boron-gallium co-doped solar cell are assembled into a main stream battery piece to obtain a photovoltaic module, and the photovoltaic module is subjected to light soaking test at 1000W / cm 2 . The test results are shown in Figure 6 , and Figure 6 can be seen that the battery degradation rate of the boron-gallium co-doped main stream photovoltaic module is 0.93% after 13h, and the degradation rate tends to be stable thereafter. The battery degradation rate of the boron-doped main stream photovoltaic module is 1.95% after 24h, and it still shows a continuous upward trend as the light soaking time increases.

[0088] The solar cell of the present application will be specifically described below in conjunction with specific examples and comparative examples.

[0089] Example 1

[0090] The present embodiment provides a TOPCon solar cell, comprising:

[0091] An N-type silicon substrate comprising a front surface and a back surface;

[0092] a boron-gallium co-doped layer on the front side, the thickness of the boron-gallium co-doped layer being 1 pm;

[0093] a first passivation layer on a surface of the boron-gallium co-doped layer away from the N-type silicon substrate;

[0094] a second passivation layer on a surface of the first passivation layer away from the boron-gallium co-doped layer, the total thickness of the first passivation layer and the second passivation layer being 70 pm;

[0095] a first electrode on a surface of the first passivation layer away from the first passivation layer;

[0096] a tunneling layer on the back side, the thickness of the tunneling layer being 1 nm;

[0097] a doped polysilicon layer on a surface of the tunneling layer away from the N-type silicon substrate, the thickness of the doped polysilicon layer being 100 nm;

[0098] a third passivation layer on a surface of the doped polysilicon layer away from the tunneling layer, the thickness of the third passivation layer being 75 pm;

[0099] a second electrode on a surface of the third passivation layer away from the doped polysilicon layer.

[0100] Embodiment 2

[0101] The present embodiment provides a TOPCon solar cell, the only difference between the TOPCon solar cell and the embodiment 1 is that the thickness of the boron-gallium co-doped layer is 0.5 pm.

[0102] Embodiment 3

[0103] The present embodiment provides a TOPCon solar cell, the only difference between the TOPCon solar cell and the embodiment 1 is that the thickness of the boron-gallium co-doped layer is 1.5 pm.

[0104] Embodiment 4

[0105] The present embodiment provides a TOPCon solar cell, the only difference between the TOPCon solar cell and the embodiment 1 is that the total thickness of the first passivation layer and the second passivation layer is 65 pm.

[0106] Embodiment 5

[0107] The present embodiment provides a TOPCon solar cell, the only difference between the TOPCon solar cell and the embodiment 1 is that the total thickness of the first passivation layer and the second passivation layer is 90 pm.

[0108] Embodiment 6

[0109] The present embodiment provides a TOPCon solar cell, which is the only difference from the embodiment 1 that the thickness of the tunneling layer is 0.5 nm.

[0110] Embodiment 7

[0111] The present embodiment provides a TOPCon solar cell, which is the only difference from the embodiment 1 that the thickness of the tunneling layer is 1.5 nm.

[0112] Embodiment 8

[0113] The present embodiment provides a TOPCon solar cell, which is the only difference from the embodiment 1 that the thickness of the doped poly-silicon layer is 60 nm.

[0114] Embodiment 9

[0115] The present embodiment provides a TOPCon solar cell, which is the only difference from the embodiment 1 that the thickness of the doped poly-silicon layer is 180 nm.

[0116] Embodiment 10

[0117] The present embodiment provides a TOPCon solar cell, which is the only difference from the embodiment 1 that the thickness of the third passivation layer is 65 pm.

[0118] Embodiment 11

[0119] The present embodiment provides a TOPCon solar cell, which is the only difference from the embodiment 1 that the thickness of the third passivation layer is 90 pm.

[0120] Comparative Example 1

[0121] The present embodiment provides a TOPCon solar cell, which is the only difference from the embodiment 1 that the thickness of the boron-gallium co-doped layer is 0.3 pm.

[0122] Comparative Example 2

[0123] The present embodiment provides a TOPCon solar cell, which is the only difference from the embodiment 1 that the thickness of the boron-gallium co-doped layer is 1.8 pm.

[0124] Comparative Example 3

[0125] The present embodiment provides a TOPCon solar cell, which is only different from the embodiment 1 in that the total thickness of the first passivation layer and the second passivation layer is 60 pm.

[0126] Comparative example 4

[0127] The present embodiment provides a TOPCon solar cell, which is only different from the embodiment 1 in that the total thickness of the first passivation layer and the second passivation layer is 95 pm.

[0128] Comparative example 5

[0129] The present embodiment provides a TOPCon solar cell, which is only different from the embodiment 1 in that the thickness of the tunneling layer is 0.2 nm.

[0130] Comparative example 6

[0131] The present embodiment provides a TOPCon solar cell, which is only different from the embodiment 1 in that the thickness of the tunneling layer is 1.8 nm.

[0132] Comparative example 7

[0133] The present embodiment provides a TOPCon solar cell, which is only different from the embodiment 1 in that the thickness of the doped poly-silicon layer is 50 nm.

[0134] Comparative example 8

[0135] The present embodiment provides a TOPCon solar cell, which is only different from the embodiment 1 in that the thickness of the doped poly-silicon layer is 200 nm.

[0136] Comparative example 9

[0137] The present embodiment provides a TOPCon solar cell, which is only different from the embodiment 1 in that the thickness of the third passivation layer is 60 pm.

[0138] Comparative example 10

[0139] The present embodiment provides a TOPCon solar cell, which is only different from the embodiment 1 in that the thickness of the third passivation layer is 100 pm.

[0140] Table 1

[0141]

[0142]

[0143] From the experimental data, it can be seen that the photoelectric conversion efficiency, open circuit voltage and short circuit current in examples 1 to 11 are higher than those in comparative examples 1 to 10, and the carrier recombination loss in examples 1 to 11 is lower than that in comparative examples 1 to 10, indicating that the solar cell of the application can effectively reduce the carrier recombination loss, improve the photoelectric conversion efficiency, and effectively improve the open circuit voltage and short circuit current of the solar cell.

[0144] From the above description, it can be seen that the embodiments described in the application achieve the following technical effects:

[0145] 1) In the TOPCon solar cell of the application, a boron-gallium co-doped layer is arranged on the N-type silicon substrate, and the two form a PN junction. Since the atomic radius of gallium in the boron-gallium co-doped layer is large, it can hinder the formation of the PN junction metastable B-O complex, thereby reducing the interface recombination of the TOPCon solar cell, improving the open circuit voltage and short circuit current of the TOPCon solar cell, reducing the light-induced decay, and achieving the improvement of the photoelectric conversion efficiency.

[0146] 2) The photovoltaic module of the application comprises the TOPCon solar cell described above. The TOPCon solar cell has a boron-gallium co-doped layer arranged on the N-type silicon substrate, and the two form a PN junction. Since the atomic radius of gallium in the boron-gallium co-doped layer is large, it can hinder the formation of the PN junction metastable B-O complex, thereby reducing the interface recombination of the TOPCon solar cell, improving the open circuit voltage and short circuit current of the photovoltaic module, reducing the light-induced decay, and improving the photoelectric conversion capability and efficiency of the photovoltaic module.

[0147] The above only describes the preferred embodiments of the application and is not intended to limit the application. Those skilled in the art can make various modifications and changes to the application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the application shall be included in the protection scope of the application.

Claims

1. A TOPCon solar cell, characterized in that, Comprising: an N-type silicon substrate comprising a front surface and a back surface; a boron-gallium co-doped layer located on the front surface; a first stacked passivation structure located on a surface of the boron-gallium co-doped layer away from the N-type silicon substrate; a first electrode located on a surface of the first stacked passivation structure away from the boron-gallium co-doped layer; a second stacked passivation structure located on the back surface; a second electrode located on a surface of the second stacked passivation structure away from the N-type silicon substrate.

2. The TOPCon solar cell according to claim 1, characterized in that The boron-gallium co-doped layer has a thickness of 0.5-1.5 μm.

3. The TOPCon solar cell according to claim 1, characterized in that The first stacked passivation structure comprises: a first passivation layer located on a surface of the boron-gallium co-doped layer away from the N-type silicon substrate; a second passivation layer located on a surface of the first passivation layer away from the boron-gallium co-doped layer.

4. The TOPCon solar cell according to claim 3, characterized in that The first passivation layer is a silicon oxide layer, and the second passivation layer is a silicon oxynitride layer, and the total thickness of the first passivation layer and the second passivation layer is 65-90 μm.

5. The TOPCon solar cell according to any one of claims 1 to 4, characterized in that, The second stacked passivation structure comprises: a tunneling layer located on the back surface; a doped polysilicon layer located on a surface of the tunneling layer away from the N-type silicon substrate; a third passivation layer located on a surface of the doped polysilicon layer away from the tunneling layer.

6. The TOPCon solar cell according to claim 5, characterized in that The tunneling layer has a thickness of 0.5-1.5 nm, and the doped polysilicon layer has a thickness of 60-180 nm.

7. The TOPCon solar cell according to claim 5, characterized in that The tunneling layer is a silicon oxide layer, and the third passivation layer comprises a silicon oxide layer and a silicon oxynitride layer stacked in a direction away from the doped polysilicon layer.

8. The TOPCon solar cell according to claim 7, characterized in that The third passivation layer has a thickness of 65-90 μm.

9. The TOPCon solar cell according to any one of claims 1 to 4, characterized in that, At least one of the front surface and the back surface has a pyramid-shaped anti-reflection texture structure.

10. A photovoltaic module, characterized by, Comprising: The TOPCon solar cell of any one of claims 1-9.

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