Solar cell, manufacturing method thereof and photovoltaic module

Abstract

The invention provides a solar cell, a manufacturing method thereof and a photovoltaic module. The solar cell includes a substrate having a first surface and a second surface opposite to each other, the first surface including a first region and a second region; a first emitter on the first region; the second emitting electrode is located on the second region, and the doping concentration of the first emitting electrode is larger than that of the second emitting electrode; the first passivation layer is located on the side, away from the substrate, of the first emitter; the amorphous silicon layer is located on the side, away from the substrate, of the first passivation layer; the second passivation layer is located on the side, away from the first passivation layer, of the amorphous silicon layer; the tunneling dielectric layer is located on the second surface; the doping layer is positioned on one side, far away from the substrate, of the tunneling dielectric layer; the third passivation layer is located on the side, away from the tunneling dielectric layer, of the doping layer; the first conductive part is located on the surface, away from the amorphous silicon layer, of the second passivation layer; the second conductive part is located on the surface, away from the doping layer, of the third passivation layer.

Description

Technical Field

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

[0002] A solar cell is a structure that uses the photovoltaic effect to convert light energy into electrical energy. When sunlight shines on the semiconductor pn junction of a solar cell, new hole-electron pairs are formed. Under the action of the built-in electric field of the pn junction, the photogenerated holes flow to the p region and the photogenerated electrons flow to the n region. When the circuit is connected, current is generated. In current solar cells, the carrier recombination loss is high, resulting in poor overall performance of the solar cell. Summary of the invention

[0003] The main purpose of the present application is to provide a solar cell, a method for manufacturing the same and a photovoltaic module, so as to at least solve the problem of high carrier recombination loss of solar cells in the prior art.

[0004] To achieve the above-mentioned purpose, according to one aspect of the present application, a solar cell is provided, comprising: a substrate having a first surface and a second surface opposite to each other, the first surface comprising a first region and a second region arranged alternately; a first emitter located on the first region; a second emitter located on the second region, the doping concentration of the first emitter being greater than the doping concentration of the second emitter; a first passivation layer located on a side of the first emitter away from the substrate, the orthographic projection of the first passivation layer on the first surface being located in the first region; an amorphous silicon layer located on a side of the first passivation layer away from the substrate, the orthographic projection of the amorphous silicon layer on the first surface being located in the first region; a second passivation layer located on a side of the amorphous silicon layer away from the first passivation layer; a tunneling dielectric layer located on the second surface; a doped layer located on a side of the tunneling dielectric layer away from the substrate; a third passivation layer located on a side of the doped layer away from the tunneling dielectric layer; a first conductive portion located on a surface of the second passivation layer away from the amorphous silicon layer, the orthographic projection of the first conductive portion on the first surface being located in the first region; and a second conductive portion located on a surface of the third passivation layer away from the doped layer.

[0005] Optionally, the doping concentration of the amorphous silicon layer is greater than the doping concentration of the second emitter and is not greater than the doping concentration of the first emitter.

[0006] Optionally, the doping concentration of the first emitter is 1×10 19 ~1×10 22 cm 3 , the doping concentration of the second emitter is 1×10 17 ~1×10 20 cm 3 The doping concentration of the amorphous silicon layer is 1×10 19 ~1×10 22 cm3 .

[0007] Optionally, the material of the first passivation layer includes at least one of the following: silicon oxide, silicon nitride, and aluminum oxide.

[0008] Optionally, the thickness of the first passivation layer is 0.5-2 nm.

[0009] Optionally, the doping type of the amorphous silicon layer, the doping type of the first emitter and the doping type of the second emitter are the same, and the doping type of the amorphous silicon layer is different from the doping type of the substrate.

[0010] Optionally, the amorphous silicon layer has a thickness of 5-50 nm.

[0011] According to another aspect of the present application, a method for manufacturing a solar cell is provided, comprising: providing a substrate, the substrate having a first surface and a second surface relative to each other, the first surface comprising first regions and second regions arranged alternately; forming a first emitter located on the first region and a second emitter located on the second region, the doping concentration of the first emitter being greater than the doping concentration of the second emitter; forming a first passivation layer, an amorphous silicon layer, and a second passivation layer in sequence on a side of the first emitter and the second emitter away from the substrate in a direction away from the substrate; forming a tunneling dielectric layer, a doping layer, and a third passivation layer in sequence on the second surface in a direction away from the substrate; forming a first conductive portion on a surface of the second passivation layer away from the amorphous silicon layer, and forming a second conductive portion on a surface of the third passivation layer away from the doping layer, wherein the orthographic projections of the first passivation layer, the amorphous silicon layer, and the first conductive portion on the first surface are respectively located in the first region.

[0012] Optionally, a first passivation layer, an amorphous silicon layer, and a second passivation layer are sequentially formed on a side of the first emitter and the second emitter away from the substrate in a direction away from the substrate, including: forming a first passivation layer on a surface of the first emitter away from the substrate; forming an amorphous silicon layer on a surface of the first passivation layer away from the first emitter using plasma enhanced chemical vapor deposition; and forming a second passivation layer on a surface of the amorphous silicon layer away from the first passivation layer and on a surface of the second emitter away from the substrate.

[0013] According to another aspect of the present application, a photovoltaic assembly is provided, comprising: any type of solar cell; a first encapsulation layer located on one side of the solar cell; and a second encapsulation layer located on a side of the solar cell away from the first encapsulation layer.

[0014] By applying the technical solution of the present application, the first passivation layer in the present application can form a good chemical passivation on the first emitter, reduce the interface state density between the first emitter and the amorphous silicon layer, and reduce the carrier recombination loss; the first passivation layer can also serve as a barrier layer between the first emitter and the first conductive part, thereby preventing the metal atoms of the first conductive part from diffusing into the first emitter, and reducing the carrier recombination loss between the two; the amorphous silicon layer serves as a barrier layer between the first emitter and the first conductive part, which can prevent the metal atoms of the first conductive part from diffusing into the first emitter, thereby reducing the carrier recombination loss between the two, and improving the photoelectric conversion efficiency of the solar cell. In addition, the present application adopts a selective emitter structure, and a heavily doped first emitter is arranged between the first conductive part and the first region, which reduces the contact resistance and metal recombination of the first region, and improves the open circuit voltage of the solar cell. A lightly doped second emitter is arranged in the second region, which can reduce the Auger recombination and improve the short-wave quantum efficiency, thereby improving the short-circuit current of the solar cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The drawings constituting part of the present application are used to provide a further understanding of the present application. The exemplary embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0016] Figure 1 A schematic cross-sectional structure diagram of a solar cell provided in an embodiment of the present application is shown;

[0017] Figure 2 A schematic flow chart of a method for manufacturing a solar cell provided according to an embodiment of the present application is shown.

[0018] The above drawings include the following reference numerals:

[0019] 10. Substrate; 11. First emitter; 12. Second emitter; 13. First passivation layer; 14. Amorphous silicon layer; 15. Second passivation layer; 16. Tunneling dielectric layer; 17. Doped layer; 18. Third passivation layer; 19. First conductive portion; 20. Second conductive portion. DETAILED DESCRIPTION

[0020] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0021] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present application.

[0022] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the accompanying drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequential order. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present application described here. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0023] As introduced in the background technology, there is a technical problem in the prior art that the carrier recombination loss of solar cells is relatively high. To solve this technical problem, the embodiments of the present application provide a solar cell, a manufacturing method thereof, and a photovoltaic module.

[0024] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0025] The present application embodiment provides a solar cell, Figure 1 The cross-sectional structure diagram of a solar cell provided by an embodiment of the present application is exemplarily shown. Figure 1 As shown, the solar cell comprises:

[0026] The substrate 10 has a first surface and a second surface opposite to each other, wherein the first surface includes first areas and second areas arranged alternately;

[0027] A first emitter 11, located on the first region;

[0028] a second emitter 12, located on the second region, wherein the doping concentration of the first emitter 11 is greater than the doping concentration of the second emitter 12;

[0029] A first passivation layer 13, located on a side of the first emitter 11 away from the substrate 10, wherein an orthographic projection of the first passivation layer 13 on the first surface is located in the first region;

[0030] an amorphous silicon layer 14, located on a side of the first passivation layer 13 away from the substrate 10, wherein an orthographic projection of the amorphous silicon layer 14 on the first surface is located in the first region;

[0031] A second passivation layer 15, located on a side of the amorphous silicon layer away from the first passivation layer 13;

[0032] A tunneling dielectric layer 16, located on the second surface;

[0033] a doping layer 17, located on a side of the tunnel dielectric layer 16 away from the substrate 10;

[0034] A third passivation layer 18, located on a side of the doping layer 17 away from the tunnel dielectric layer 16;

[0035] A first conductive portion 19 is located on a surface of the second passivation layer 15 away from the amorphous silicon layer 14, and an orthographic projection of the first conductive portion 19 on the first surface is located in the first region;

[0036] The second conductive portion 20 is located on a surface of the third passivation layer 18 away from the doping layer 17 .

[0037] According to the embodiment, a first emitter is arranged on the first area of ​​the first surface of the substrate, a second emitter with a doping concentration lower than that of the first emitter is arranged on the second area of ​​the first surface of the substrate, a first passivation layer, an amorphous silicon layer, a second passivation layer and a first conductive part are arranged in sequence on the side of the first emitter away from the substrate, and the orthographic projections of the first passivation layer, the amorphous silicon layer and the first conductive part on the substrate are all located in the first area, and a tunnel dielectric layer, a doping layer, a third passivation layer and a second conductive part are arranged in sequence on the second surface of the substrate. In the present application, the first passivation layer can form a good chemical passivation on the first emitter, reduce the interface state density between the first emitter and the amorphous silicon layer, and reduce the carrier recombination loss; the first passivation layer can also serve as a barrier layer between the first emitter and the first conductive part, thereby preventing the metal atoms of the first conductive part from diffusing into the first emitter, thereby reducing the carrier recombination loss between the two; the amorphous silicon layer, as a barrier layer between the first emitter and the first conductive part, can prevent the metal atoms of the first conductive part from diffusing into the first emitter, thereby reducing the carrier recombination loss between the two, and improving the photoelectric conversion efficiency of the solar cell. In addition, the present application adopts a selective emitter structure, and a heavily doped first emitter is arranged between the first conductive part and the first region, which reduces the contact resistance and metal recombination of the first region and improves the open circuit voltage of the solar cell. A lightly doped second emitter is arranged in the second region, which can reduce Auger recombination and improve short-wave quantum efficiency, thereby increasing the short-circuit current of the solar cell.

[0038] The solar cell of the present application may be a TOPCon (Tunnel Oxide Passivated Contact) cell.

[0039] In some embodiments, the first passivation layer 13 may be located on the surface of the first emitter 11 away from the substrate 10; other film structures may be provided between the first passivation layer 13 and the first emitter 11. The amorphous silicon layer 14 may be located on the surface of the first passivation layer 13 away from the substrate 10; other film structures may be provided between the amorphous silicon layer 14 and the first passivation layer 13. The second passivation layer 15 may be located on the surface of the amorphous silicon layer 14 away from the first passivation layer 13; other film structures may be provided between the second passivation layer 15 and the amorphous silicon layer 14. The tunneling dielectric layer 16, the doping layer 17 and the third passivation layer 18 may be stacked in sequence; other film structures may be provided between the tunneling dielectric layer 16 and the doping layer 17; other film structures may be provided between the doping layer 17 and the third passivation layer 18. The second passivation layer 15 may be located not only on the side of the amorphous silicon layer 14 away from the first passivation layer 13 , but also on the side of the second emitter 12 away from the substrate 10 .

[0040] In some optional solutions, the solar cell can be a single-sided cell, that is, it receives solar light only through the first surface of the substrate 10. In other optional solutions, the solar cell can be a double-sided cell, that is, it receives solar light through the front and back sides of the substrate 10.

[0041] Specifically, the area on the first surface of the substrate 10 other than the first area is the second area. The first area is the area where the orthographic projection of the first conductive portion 19 on the substrate is located, and the area of ​​the first area is larger than the area of ​​the orthographic projection of the first conductive portion 19 on the substrate.

[0042] According to some exemplary embodiments of the present application, the substrate 10 can receive incident light and generate photogenerated carriers. The first surface of the substrate 10 serves as the front surface of the substrate 10, and the second surface of the substrate 10 serves as the back surface of the substrate 10. The substrate 10 can be a silicon substrate 10, and the material of the silicon substrate 10 includes but is not limited to single crystal silicon, polycrystalline silicon, amorphous silicon, and microcrystalline silicon. The first conductive portion 19 is electrically connected to the first emitter 11, and the second conductive portion 20 is electrically connected to the doping layer 17.

[0043] Those skilled in the art can set the morphology of the first surface and the second surface of the substrate 10 according to actual needs. According to some optional embodiments of the present application, the first surface of the substrate 10 can be set to a pyramid velvet surface, so that the reflectivity of the first surface to the incident light is small, thereby increasing the absorption utilization rate of the light on the first surface of the substrate 10. The second surface of the substrate 10 can be set to a pyramid velvet surface, so that the reflectivity of the second surface to the incident light is small, thereby increasing the absorption utilization rate of the light on the second surface of the substrate 10. The second surface of the substrate 10 can be set to a non-pyramid velvet surface, such as a stacked step morphology, so that the tunneling dielectric layer 16 located on the second surface has a higher density and uniformity, so that the tunneling dielectric layer 16 has a good passivation effect on the second surface.

[0044] In some alternatives, the first passivation layer 13 may be a single-layer film structure or a multi-layer film structure. The material of the first passivation layer 13 may include at least one of magnesium fluoride, silicon oxide, aluminum oxide, silicon oxynitride, silicon nitride and titanium oxide.

[0045] In the present application, the material of the first passivation layer 13 includes at least one of the following: silicon oxide, silicon nitride, and aluminum oxide.

[0046] In some embodiments, the second passivation layer 15 can play a passivation role. In addition, the second passivation layer 15 can also reduce the reflection of the first surface of the substrate 10 to the incident light. The second passivation layer 15 can be a single-layer film structure or a multi-layer film structure. The material of the second passivation layer 15 can include at least one of magnesium fluoride, silicon oxide, aluminum oxide, silicon oxynitride, silicon nitride and titanium oxide.

[0047] Specifically, the tunnel dielectric layer 16 can play the role of chemical passivation on the substrate 10. In addition, the tunnel dielectric layer 16 can cause the energy band of the second surface to shift asymmetrically, so that the barrier to the majority carriers is lower than the barrier to the minority carriers. Therefore, the majority carriers can easily perform quantum tunneling through the tunnel dielectric layer 16, while the minority carriers are difficult to pass through the tunnel dielectric layer 16, so as to achieve selective transmission of carriers. The material of the tunnel dielectric layer 16 can be a dielectric material, such as silicon oxide.

[0048] In some embodiments, the doping layer 17 may form a field passivation. The doping type of the doping layer 17 may be the same as the doping type of the substrate 10. The material of the doping layer 17 may be doped silicon, which may specifically include doped polysilicon, doped microcrystalline silicon, or doped amorphous silicon.

[0049] In some embodiments, Figure 1As shown, there are multiple first conductive parts 19, corresponding to multiple first regions, corresponding to multiple first emitters 11, first passivation layers 13 and amorphous silicon layers 14, and the first emitter 11 corresponds one-to-one to the first passivation layer 13, the amorphous silicon layer 14 and the first conductive part 19.

[0050] In some embodiments, Figure 1 As shown, there are multiple second conductive parts 20.

[0051] In actual application, the materials of the first passivation layer, the second passivation layer and the third passivation layer can be the same, for example, silicon oxide. The materials of the first passivation layer, the second passivation layer and the third passivation layer can also be different. The materials of the first conductive part and the second conductive part can be any suitable metal material.

[0052] In some exemplary embodiments, the doping type of the amorphous silicon layer 14, the doping type of the first emitter 11 and the doping type of the second emitter 12 are the same, and the doping type of the amorphous silicon layer 14 is different from the doping type of the substrate 10. The doping types of the first emitter 11 and the second emitter 12 are different from the substrate 10, so that the first emitter 11 and the second emitter 12 form a PN junction with the substrate 10. When sunlight shines on the PN junction, new hole-electron pairs are formed. Under the action of the built-in electric field of the PN junction, photogenerated holes flow to the P region and photogenerated electrons flow to the N region. When the circuit is connected, current is generated, thereby realizing the photoelectric conversion function of the solar cell.

[0053] Specifically, the substrate 10 is an N-type semiconductor substrate 10, that is, the substrate 10 is doped with N-type ions, and the N-type ions can be specifically phosphorus, arsenic or antimony. The first emitter 11 and the second emitter 12 can be P-type emitters, that is, the first emitter 11 and the second emitter 12 are doped with P-type ions, and the P-type ions can be boron, aluminum or gallium. The first emitter 11 and the second emitter 12 both form a PN junction with the substrate 10. The first emitter 11 and the second emitter 12 can be obtained by diffusing and doping the first surface of the substrate 10 with P-type ions, and the doped part of the substrate 10 is converted into the first emitter 11 and the second emitter 12. The amorphous silicon layer 14 is a P-type amorphous silicon layer 14, doped with P-type ions, and the P-type ions can be any one of boron, aluminum or gallium. The doping layer 17 is an N-type conductive layer, doped with N-type ions, and the N-type ions can be specifically any one of phosphorus, arsenic or antimony.

[0054] Specifically, the first emitter 11 and the amorphous silicon layer 14 are made of different materials, so a heterojunction structure with the same doping type but different doping concentrations is formed between the first emitter 11 and the amorphous silicon layer 14. The heterojunction structure can improve the field passivation effect and reduce carrier recombination losses.

[0055] Optionally, the doping concentration of the amorphous silicon layer 14 is greater than the doping concentration of the second emitter 12 and not greater than the doping concentration of the first emitter 11. In order to ensure the normal transmission of carriers, the concentration of the amorphous silicon layer 14 cannot be too low. The doping concentration of the amorphous silicon layer 14 is greater than the doping concentration of the second emitter 12. The two form a high-low junction, which is beneficial to reduce the carrier recombination of the second emitter 12; and setting the doping concentration of the amorphous silicon layer 14 to be less than or equal to the doping concentration of the first emitter 11 can reduce the Auger recombination of this film layer and reduce the probability of carrier recombination. In addition, compared with the emitter structure with uniform doping concentration, the present application selectively performs high doping in the first region corresponding to the first conductive part 19 and low doping in the second region not corresponding to the first conductive part 19. High doping can further reduce the contact resistance and metal recombination of the first region, improve the open circuit voltage, and low doping can further reduce Auger recombination, improve short-wave quantum efficiency, and thus improve the short-circuit current.

[0056] Optionally, the doping concentration of the first emitter 11 is 1×10 19 ~1×10 22 cm 3 For example, the doping concentration of the first emitter 11 may be 1×10 19 cm 3 , 2×10 20 cm 3 , 5.3×10 21 cm 3 or 1×10 22 cm 3 , the doping concentration of the second emitter 12 is 1×10 17 ~1×10 20 cm 3 For example, the doping concentration of the second emitter 12 may be 1×10 17 cm 3 , 5×10 18 cm 3 , 4×10 19 cm 3 , or 1×10 20 cm 3 The doping concentration of the amorphous silicon layer 14 is 1×10 19 ~1×10 22 cm 3For example, the doping concentration of the amorphous silicon layer 14 may be 1×10 29 cm 3 , 2×10 20 cm 3 , 7×10 21 cm 3 , or 1×10 22 cm 3 .

[0057] In the embodiment, the doping concentration of the first emitter 11 is 1×10 19 ~1×10 22 cm 3 In this range, the high doping concentration of the first emitter 11 is ensured, so that the first emitter 11 has a small square resistance, which can increase the carrier transmission efficiency; and the top surface doping concentration of the first emitter 11 is prevented from being too high, that is, the content of the doping element in the first emitter 11 is not too much, so that the problem of more doping elements becoming strong recombination centers due to excessive doping elements in the first emitter 11, resulting in poor passivation ability of the first emitter 11, can be avoided. The doping concentration of the second emitter 12 is between 1×10 17 ~1×10 20 cm 3 Within this range, the doping elements in the second emitter 12 are less, which can maintain a good passivation effect and further improve the open circuit voltage and short circuit current of the solar cell; the doping concentration of the amorphous silicon layer 14 is between 1×10 19 ~1×10 22 Within this range, it can be ensured that the content of the doping element in the amorphous silicon layer 14 is not excessive, thereby further ensuring that the passivation effect of the amorphous silicon layer 14 is better.

[0058] Specifically, the doping concentration of the first emitter 11 is 1×10 19 cm -3 ~1×10 22 cm -3 In the case where the recombination current density of the first emitter 11 is less than 500 fAcm -2 The doping concentration of the second emitter 12 is 1×10 17 cm -3 ~1×10 20 cm -3 In the case where the recombination current density of the second emitter 12 is less than 100 fAcm -2 The doping concentration of the amorphous silicon layer 14 is 1×10 19 cm -3 ~1×10 22 cm -3In the case of -2 .

[0059] Optionally, the thickness of the first passivation layer 13 is 0.5-2 nm. For example, the thickness of the first passivation layer 13 may be 0.5 nm, 1 nm, 1.5 nm or 2 nm. This range is neither too thick to cause excessive resistance and reduce the current density of the solar cell, nor too thin to affect the passivation effect of the first passivation layer 13 and fail to achieve the desired passivation effect.

[0060] In some other exemplary embodiments, the thickness of the amorphous silicon layer 14 is 5 to 50 nm. For example, the thickness of the amorphous silicon layer 14 may be 5 nm, 10 nm, 15 nm, 20 nm, 30 nm, 40 nm, or 50 nm. The thickness of the amorphous silicon layer is within the range of 5 to 50 nm, which is neither too thick to make the doping process of the amorphous silicon layer 14 difficult to implement, nor too thin to make the amorphous silicon layer 14 unable to achieve the desired passivation effect.

[0061] The embodiment of the present application also provides a method for manufacturing the solar cell. Figure 2 FIG. 1 is a flow chart of a method for manufacturing a solar cell according to an embodiment of the present application. Figure 2 As shown, the method comprises the following steps:

[0062] Step S201, providing a substrate, wherein the substrate has a first surface and a second surface opposite to each other, wherein the first surface includes first areas and second areas arranged alternately;

[0063] Step S202, forming a first emitter located on the first region and a second emitter located on the second region, wherein the doping concentration of the first emitter is greater than the doping concentration of the second emitter;

[0064] Step S203, forming a first passivation layer, an amorphous silicon layer, and a second passivation layer in sequence along a direction away from the substrate on a side of the first emitter and the second emitter away from the substrate;

[0065] Step S204, forming a tunnel dielectric layer, a doping layer and a third passivation layer in sequence on the second surface in a direction away from the substrate;

[0066] Step S205, forming a first conductive portion on the surface of the second passivation layer away from the amorphous silicon layer, and forming a second conductive portion on the surface of the third passivation layer away from the doped layer, wherein the orthographic projections of the first passivation layer, the amorphous silicon layer and the first conductive portion on the first surface are respectively located in the first region.

[0067] According to the embodiment, a substrate is first provided, wherein the first surface of the substrate includes first and second regions arranged alternately; then a first emitter is formed on the first region of the first surface of the substrate, and a second emitter is formed on the second region of the first surface of the substrate, wherein the doping concentration of the first emitter is higher than that of the second emitter; then a first passivation layer, an amorphous silicon layer, and a second passivation layer are sequentially formed on the side of the first emitter and the second emitter away from the substrate; and a tunneling dielectric layer, a doping layer, and a third passivation layer are sequentially formed on the second surface of the substrate; finally, a first conductive portion is formed on the surface of the second passivation layer away from the amorphous silicon layer, and a second conductive portion is formed on the surface of the third passivation layer away from the doping layer, so that the orthographic projections of the first passivation layer, the amorphous silicon layer, and the first conductive portion on the first surface of the substrate are respectively located in the first region. The method of the present application forms a first passivation layer and an amorphous silicon layer between the first emitter and the first conductive part, and the first passivation layer can form a good chemical passivation on the first emitter, reduce the interface state density between the first emitter and the amorphous silicon layer, and reduce the carrier recombination loss; the first passivation layer can also serve as a barrier layer between the first emitter and the first conductive part, thereby preventing the metal atoms of the first conductive part from diffusing into the first emitter, and reducing the carrier recombination loss between the two; the amorphous silicon layer serves as a barrier layer between the first emitter and the first conductive part, which can prevent the metal atoms of the first conductive part from diffusing into the first emitter, thereby reducing the carrier recombination loss between the two, and improving the photoelectric conversion efficiency of the solar cell. In addition, the present application adopts a selective emitter structure, and a heavily doped first emitter is arranged between the first conductive part and the first region, which reduces the contact resistance and metal recombination of the first region, and improves the open circuit voltage of the solar cell. A lightly doped second emitter is arranged in the second region, which can reduce the Auger recombination and improve the short-wave quantum efficiency, thereby improving the short-circuit current of the solar cell.

[0068] In an optional solution, a first passivation layer, an amorphous silicon layer, and a second passivation layer are sequentially formed on the side of the first emitter and the second emitter away from the substrate in a direction away from the substrate, including: forming the first passivation layer on the surface of the first emitter away from the substrate; forming the amorphous silicon layer on the surface of the first passivation layer away from the first emitter by plasma enhanced chemical vapor deposition; forming the second passivation layer on the surface of the amorphous silicon layer away from the first passivation layer and on the surface of the second emitter away from the substrate. In this embodiment, the amorphous silicon layer is deposited by plasma enhanced chemical vapor deposition, which can make the thickness uniformity of the amorphous silicon layer better, reduce the non-uniformity in the film forming process, realize high-speed film forming at a lower temperature, improve production efficiency, activate gas phase reactants, improve the cleanliness and density of the amorphous silicon layer, thereby improving the deposition quality, and can also eliminate residual gas during the deposition process, so that the film forming process is relatively clean, and reduce the influence of residues on the performance of the amorphous silicon layer.

[0069] Furthermore, the first passivation layer may be formed on the surface of the first emitter away from the substrate by a thermal oxidation method, or may be formed on the surface of the first emitter away from the substrate by a chemical vapor deposition method.

[0070] Furthermore, the second passivation layer can be formed on the surface of the amorphous silicon layer away from the first passivation layer and on the surface of the second emitter away from the substrate by a thermal oxidation method, or the second passivation layer can be formed on the surface of the amorphous silicon layer away from the first passivation layer and on the surface of the second emitter away from the substrate by a chemical vapor deposition method.

[0071] Furthermore, the amorphous silicon layer is formed on the surface of the first passivation layer away from the first emitter by plasma enhanced chemical vapor deposition, including: depositing amorphous silicon material on the surface of the first passivation layer away from the first emitter by plasma enhanced chemical vapor deposition to obtain a preliminary amorphous silicon layer; and ion implanting the preliminary amorphous silicon layer to make its doping concentration greater than the doping concentration of the second emitter and not greater than the doping concentration of the first emitter to obtain the amorphous silicon layer.

[0072] In an exemplary embodiment, the doping concentration of the first emitter is 1×10 19 ~1×10 22 cm 3 , the doping concentration of the second emitter is 1×10 17 ~1×10 20 cm 3 The doping concentration of the amorphous silicon layer is 1×10 19 ~1×1022 cm 3 .

[0073] Furthermore, forming the amorphous silicon layer on the surface of the first passivation layer away from the first emitter by using plasma enhanced chemical vapor deposition may also include: forming the amorphous silicon layer with a thickness of 5 to 50 nm on the surface of the first passivation layer away from the first emitter by using plasma enhanced chemical vapor deposition.

[0074] In some embodiments, forming a first emitter located on the first region and a second emitter located on the second region may include: using a furnace tube diffusion process to process a preparatory substrate, one side surface of the preparatory substrate including the first region and the second region, to form the first emitter on the first region of the preparatory substrate, and to form the second emitter on the second region of the preparatory substrate, and the remaining preparatory substrate forms the substrate.

[0075] A first conductive portion is formed on a surface of the second passivation layer away from the amorphous silicon layer, and a second conductive portion is formed on a surface of the third passivation layer away from the doped layer, specifically comprising: using screen printing technology to print a first silver paste screen printing mesh on a surface of the third passivation layer away from the doped layer; curing the first silver paste screen printing mesh, and sintering the cured first silver paste screen printing mesh below 300° C. to obtain the second conductive portion; using screen printing technology to print a second silver paste screen printing mesh on a surface of the second passivation layer away from the amorphous silicon layer; curing the second silver paste screen printing mesh, and sintering the cured second silver paste screen printing mesh below 300° C. to obtain the first conductive portion.

[0076] According to some further optional embodiments of the present application, a first passivation layer is formed on a side of the first emitter and the second emitter away from the substrate, including: forming the first passivation layer with a thickness of 0.5 to 2 nm on a side of the first emitter and the second emitter away from the substrate.

[0077] An embodiment of the present application further provides a photovoltaic assembly, comprising: any one of the above-mentioned solar cells; a first encapsulation layer located on one side of the solar cell; and a second encapsulation layer located on a side of the solar cell away from the first encapsulation layer.

[0078] The photovoltaic module comprises the solar cell and the first encapsulation layer and the second encapsulation layer located on both sides of the solar cell, the first encapsulation layer and the second encapsulation layer can play a sealing and protective role for the solar cell, in the solar cell, a first emitter is arranged on the first area of ​​the first surface of the substrate, a second emitter with a doping concentration lower than that of the first emitter is arranged on the second area of ​​the first surface of the substrate, a first passivation layer, an amorphous silicon layer, a second passivation layer and a first conductive part are arranged in sequence on the side of the first emitter away from the substrate, the orthographic projections of the first passivation layer, the amorphous silicon layer and the first conductive part on the substrate are all located in the first area, and a tunnel dielectric layer, a doping layer are arranged in sequence on the second surface of the substrate , a third passivation layer and a second conductive part, wherein the first passivation layer can form a good chemical passivation on the first emitter, reduce the interface state density between the first emitter and the amorphous silicon layer, and reduce the carrier recombination loss; the first passivation layer can also serve as a barrier layer between the first emitter and the first conductive part, thereby preventing the metal atoms of the first conductive part from diffusing into the first emitter, thereby reducing the carrier recombination loss between the two; the amorphous silicon layer, as a barrier layer between the first emitter and the first conductive part, can prevent the metal atoms of the first conductive part from diffusing into the first emitter, thereby reducing the carrier recombination loss between the two, and improving the photoelectric conversion efficiency of the solar cell. In addition, the present application adopts a selective emitter structure, and a heavily doped first emitter is arranged between the first conductive part and the first region, which reduces the contact resistance and metal recombination of the first region, and improves the open circuit voltage of the solar cell. A lightly doped second emitter is arranged in the second region, which can reduce Auger recombination and improve short-wave quantum efficiency, thereby improving the short-circuit current of the solar cell.

[0079] The solar cell of the present application will be described in detail below in combination with specific embodiments and comparative examples.

[0080] Example 1

[0081] This embodiment provides a solar cell, including:

[0082] A substrate having a first surface and a second surface opposite to each other, wherein the first surface includes first areas and second areas arranged alternately;

[0083] A first emitter is located on the first region, and the doping concentration of the first emitter is 1×10 19 cm 3 ;

[0084] A second emitter is located on the second region, and the doping concentration of the second emitter is 1×10 17 cm 3 ;

[0085] A first passivation layer, located on a side of the first emitter away from the substrate, wherein an orthographic projection of the first passivation layer on the first surface is located in the first region and has a thickness of 0.5 nm;

[0086] an amorphous silicon layer, located on a side of the first passivation layer away from the substrate, wherein the orthographic projection of the amorphous silicon layer on the first surface is located in the first region, and the doping concentration of the amorphous silicon layer is 1×10 19 cm 3 , thickness is 5nm;

[0087] A second passivation layer is located on a side of the amorphous silicon layer away from the first passivation layer;

[0088] A tunneling dielectric layer, located on the second surface;

[0089] a doping layer, located on a side of the tunnel dielectric layer away from the substrate;

[0090] A third passivation layer is located on a side of the doped layer away from the tunnel dielectric layer;

[0091] A first conductive portion is located on a surface of the second passivation layer away from the amorphous silicon layer, and an orthographic projection of the first conductive portion on the first surface is located in the first region;

[0092] The second conductive portion is located on a surface of the third passivation layer away from the doping layer.

[0093] Example 2

[0094] The present application provides a solar cell. The only difference between the solar cell and the embodiment 1 is that the doping concentration of the first emitter is 1×10 22 cm 3 , the doping concentration of the second emitter is 1×10 20 cm 3 The doping concentration of the amorphous silicon layer is 1×10 22 cm 3 .

[0095] Example 3

[0096] The present application provides a solar cell. The only difference between the solar cell and the embodiment 1 is that the doping concentration of the first emitter is 1×10 20 cm 3 , the doping concentration of the second emitter is 1×10 18 cm 3 The doping concentration of the amorphous silicon layer is 1×10 20 cm 3 .

[0097] Example 4

[0098] The present application provides a solar cell, the only difference between the solar cell and Example 1 is that the thickness of the first passivation layer is 2 nm.

[0099] Example 5

[0100] The present application provides a solar cell, the only difference between the solar cell and Embodiment 1 is that the thickness of the first passivation layer is 1 nm.

[0101] Example 6

[0102] The present application provides a solar cell, the only difference between the solar cell and the embodiment 1 is that the thickness of the amorphous silicon layer is 50 nm.

[0103] Example 7

[0104] The present application provides a solar cell, the only difference between the solar cell and the embodiment 1 is that the thickness of the amorphous silicon layer is 25 nm.

[0105] Comparative Example 1

[0106] The present application provides a solar cell. The only difference between the solar cell and the embodiment 1 is that the doping concentration of the first emitter is 1×10 24 cm 3 , the doping concentration of the second emitter is 1×10 22 cm 3 The doping concentration of the amorphous silicon layer is 1×10 23 cm 3 .

[0107] Comparative Example 2

[0108] The present application provides a solar cell. The only difference between the solar cell and the embodiment 1 is that the doping concentration of the first emitter is 1×10 17 cm 3 , the doping concentration of the second emitter is 1×10 15 cm 3 The doping concentration of the amorphous silicon layer is 1×10 17 cm 3 .

[0109] Comparative Example 3

[0110] The present application provides a solar cell, the only difference between the solar cell and Embodiment 1 is that the thickness of the first passivation layer is 0.2 nm.

[0111] Comparative Example 4

[0112] The present application provides a solar cell, the only difference between the solar cell and Embodiment 1 is that the thickness of the first passivation layer is 4 nm.

[0113] Comparative Example 5

[0114] The present application provides a solar cell, the only difference between the solar cell and Example 1 is that the thickness of the amorphous silicon layer is 3 nm.

[0115] Comparative Example 6

[0116] The present application provides a solar cell, the only difference between the solar cell and the embodiment 1 is that the thickness of the amorphous silicon layer is 60 nm.

[0117] The performance of the solar cells in Examples 1 to 7 and Comparative Examples 1 to 6 was tested, and the test results are shown in Table 1:

[0118] Table 1

[0119]

[0120] It can be seen from the experimental data that the photoelectric conversion efficiency in Examples 1 to 7 is higher than that in Comparative Examples 1 to 7, and the fill factor in Examples 1 to 7 is higher than that in Comparative Examples 1 to 7, indicating that the solar cell of the present application can reduce carrier recombination losses and improve photoelectric conversion efficiency. It can also be seen from the experimental data that the open circuit voltage and short circuit current in Examples 1 to 3 are higher than those in Comparative Examples 1 and 2, indicating that the solar cell of the present application can improve the open circuit voltage and short circuit current of the solar cell.

[0121] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

[0122] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A solar cell, characterized in that: include: A substrate having a first surface and a second surface opposite to each other, wherein the first surface includes first areas and second areas arranged alternately; A first emitter, located on the first region; a second emitter, located on the second region, wherein the doping concentration of the first emitter is greater than the doping concentration of the second emitter; A first passivation layer is located on a side of the first emitter away from the substrate, and an orthographic projection of the first passivation layer on the first surface is located in the first region; an amorphous silicon layer, located on a side of the first passivation layer away from the substrate, wherein an orthographic projection of the amorphous silicon layer on the first surface is located in the first region; A second passivation layer is located on a side of the amorphous silicon layer away from the first passivation layer; A tunneling dielectric layer, located on the second surface; a doping layer, located on a side of the tunnel dielectric layer away from the substrate; A third passivation layer is located on a side of the doped layer away from the tunnel dielectric layer; A first conductive portion is located on a surface of the second passivation layer away from the amorphous silicon layer, and an orthographic projection of the first conductive portion on the first surface is located in the first region; The second conductive portion is located on a surface of the third passivation layer away from the doping layer.

2. The solar cell according to claim 1, characterized in that The doping concentration of the amorphous silicon layer is greater than the doping concentration of the second emitter and is not greater than the doping concentration of the first emitter.

3. The solar cell according to claim 2, characterized in that: The doping concentration of the first emitter is 1×10 19 ~1×10 22 cm 3 , the doping concentration of the second emitter is 1×10 17 ~1×10 20 cm 3 The doping concentration of the amorphous silicon layer is 1×10 19 ~1×10 22 cm 3 .

4. The solar cell according to any one of claims 1 to 3, characterized in that The material of the first passivation layer includes at least one of the following: silicon oxide, silicon nitride, and aluminum oxide.

5. The solar cell according to any one of claims 1 to 3, characterized in that The thickness of the first passivation layer is 0.5-2 nm.

6. The solar cell according to any one of claims 1 to 3, characterized in that: The doping type of the amorphous silicon layer, the doping type of the first emitter and the doping type of the second emitter are the same, and the doping type of the amorphous silicon layer is different from the doping type of the substrate.

7. The solar cell according to any one of claims 1 to 3, characterized in that The thickness of the amorphous silicon layer is 5-50 nm.

8. A method for manufacturing a solar cell according to any one of claims 1 to 7, characterized in that: include: Providing a substrate, the substrate having a first surface and a second surface opposite to each other, the first surface comprising first areas and second areas arranged alternately; forming a first emitter located on the first region and a second emitter located on the second region, wherein the doping concentration of the first emitter is greater than the doping concentration of the second emitter; forming a first passivation layer, an amorphous silicon layer, and a second passivation layer in sequence along a direction away from the substrate on a side of the first emitter and the second emitter away from the substrate; forming a tunnel dielectric layer, a doping layer and a third passivation layer in sequence on the second surface in a direction away from the substrate; forming a first conductive portion on a surface of the second passivation layer away from the amorphous silicon layer, and forming a second conductive portion on a surface of the third passivation layer away from the doped layer, The orthographic projections of the first passivation layer, the amorphous silicon layer, and the first conductive portion on the first surface are respectively located in the first region.

9. The method according to claim 8, characterized in that A first passivation layer, an amorphous silicon layer, and a second passivation layer are sequentially formed on a side of the first emitter and the second emitter away from the substrate in a direction away from the substrate, including: forming the first passivation layer on a surface of the first emitter away from the substrate; forming the amorphous silicon layer on the surface of the first passivation layer away from the first emitter by using a plasma enhanced chemical vapor deposition method; The second passivation layer is formed on a surface of the amorphous silicon layer away from the first passivation layer and on a surface of the second emitter away from the substrate.

10. A photovoltaic module, characterized in that: include: The solar cell according to any one of claims 1 to 7; A first encapsulation layer, located on one side of the solar cell; The second encapsulation layer is located on a side of the solar cell away from the first encapsulation layer.

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