Solar cell and manufacturing method thereof

Abstract

The invention relates to a solar cell and a manufacturing method thereof. The manufacturing method of the solar cell comprises the following steps: providing a substrate, wherein a first surface of the substrate comprises a metal contact region and a non-metal contact region; performing laser treatment on the metal contact region by using first laser to form a first tunneling oxide layer in the metal contact region; performing laser processing on the non-metal contact region by using second laser to form a second tunneling oxide layer in the non-metal contact region; wherein the power of the first laser is smaller than that of the second laser, so that the thickness of the first tunneling oxide layer is smaller than that of the second tunneling oxide layer; and forming a polycrystalline silicon doped conductive layer on one side, deviating from the substrate, of the first tunneling oxide layer and the second tunneling oxide layer. According to the solar cell and the manufacturing method thereof, the efficiency of the solar cell can be improved.

Description

Technical Field

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

[0002] In order to reduce the recombination rate, extend the minority carrier lifetime, and improve the photoelectric conversion efficiency of solar cells, in the related art, the substrate is generally passivated to form a passivation contact layer on the substrate surface to reduce the recombination of surface carriers, thereby reducing the impact caused by internal defects in the substrate. The passivation contact layer generally includes a tunneling oxide layer and a polysilicon doped conductive layer stacked on each other, and the polysilicon doped conductive layer is in ohmic contact with the electrode of the solar cell. In the related art, the quality of the tunneling oxide layer is usually improved by increasing the oxidation time of the tunneling oxide layer, thereby improving the passivation effect. However, solar cells that currently use a passivation contact layer still have the problem of high electrode contact resistance and low efficiency of the solar cell. Summary of the invention

[0003] Based on this, it is necessary to provide a solar cell with higher efficiency and a method for manufacturing the same.

[0004] An embodiment of the present application provides a method for manufacturing a solar cell, comprising:

[0005] Providing a substrate, wherein a first surface of the substrate comprises a metal contact area and a non-metal contact area;

[0006] Using a first laser to perform laser processing on the metal contact area to form a first tunneling oxide layer in the metal contact area; Using a second laser to perform laser processing on the non-metal contact area to form a second tunneling oxide layer in the non-metal contact area; wherein the power of the first laser is less than the power of the second laser, so that the thickness of the first tunneling oxide layer is less than the thickness of the second tunneling oxide layer;

[0007] A polysilicon doped conductive layer is formed on a side of the first tunnel oxide layer and the second tunnel oxide layer facing away from the substrate.

[0008] In one embodiment, the power of the first laser is in the range of 20W-40W, and the power of the second laser is in the range of 40W-60W.

[0009] In one embodiment, in the step of laser processing the metal contact region using the first laser to form a first tunnel oxide layer in the metal contact region, at least one of the following conditions is satisfied:

[0010] (1) The laser treatment using the first laser is performed in an air atmosphere;

[0011] (2) The type of the first laser is purple picosecond;

[0012] (3) The wavelength of the first laser is 355 nm;

[0013] (4) The spot size of the first laser is 200 μm x 200 μm;

[0014] (5) The scanning speed of the first laser is 10m / s-60m / s;

[0015] (6) The pulse frequency of the first laser is 200kHz-1000kHz;

[0016] (7) The power of the first laser is 30W.

[0017] In one embodiment, in the step of laser processing the non-metallic contact region using a second laser to form a second tunneling oxide layer in the non-metallic contact region, at least one of the following conditions is satisfied:

[0018] (1) The laser treatment using the second laser is performed in an air atmosphere;

[0019] (2) The type of the second laser is purple picosecond;

[0020] (3) The wavelength of the second laser is 355 nm;

[0021] (4) The spot size of the second laser is 200 μm x 200 μm;

[0022] (5) The scanning speed of the second laser is 10m / s-60m / s;

[0023] (6) The pulse frequency of the second laser is 200kHz-1000kHz;

[0024] (7) The power of the second laser is 45 W, 50 W, or 55 W.

[0025] In one embodiment, the thickness of the first tunnel oxide layer is 1.4 nm-1.6 nm; the thickness of the second tunnel oxide layer is 1.5 nm-1.8 nm.

[0026] In one embodiment, after the step of forming a polysilicon doped conductive layer on the first tunnel oxide layer and the second tunnel oxide layer on the side facing away from the substrate, the method further comprises:

[0027] forming a first passivation layer and a first anti-reflection layer in sequence on a side of the polysilicon doped conductive layer away from the substrate;

[0028] A first electrode is formed on a portion of the first anti-reflection layer covering the first tunnel oxide layer, and the first electrode is in ohmic contact with the polysilicon doped conductive layer.

[0029] In one embodiment, before forming the first tunneling oxide layer and the second tunneling oxide layer, the method for manufacturing a solar cell further includes:

[0030] A doped conductive layer is fabricated on the second surface of the substrate. The doping type of the doped conductive layer is opposite to that of the polysilicon doped conductive layer. The second surface is arranged opposite to the first surface.

[0031] In one embodiment, the substrate further includes a plurality of side surfaces adjacent to the first surface and the second surface; and the step of forming the doped conductive layer on the second surface of the substrate specifically includes:

[0032] Diffusion of a first doping element is performed on the second surface of the substrate to form a doped conductive material layer and a first oxide material layer covering the surface of the doped conductive material layer on the second surface of the substrate;

[0033] The first oxide material layer plated on the first surface and each side surface is removed by a chain machine; and the doped conductive material layer formed on the first surface and each side surface is removed by an alkaline etching solution.

[0034] In one embodiment, the step of forming a polysilicon doped conductive layer on the side of the first tunnel oxide layer and the second tunnel oxide layer facing away from the substrate specifically includes:

[0035] Forming an intrinsic amorphous silicon material layer on the surface of the first tunnel oxide layer and the second tunnel oxide layer on the side facing away from the substrate, wherein the thickness of the intrinsic amorphous silicon material layer is 80-120 nm;

[0036] The intrinsic amorphous silicon material layer is diffused with a second doping element to form the intrinsic amorphous silicon material layer into a polysilicon doping material layer, and a second oxide material layer is formed on the surface of the polysilicon doping material layer; the second doping element is opposite to the doping type of the first doping element, and during the diffusion process, the junction temperature is 800° C.-920° C., and the junction time is 200s-2000s;

[0037] The second oxide material layer plated around one side and each side of the first surface is removed by an acidic etching solution, the polysilicon doping material layer formed on one side and each side of the first surface is removed, and the first oxide material layer on one side of the first surface is removed.

[0038] A second aspect of an embodiment of the present application provides a solar cell, which is manufactured using the above-mentioned method for manufacturing a solar cell.

[0039] The above-mentioned solar cell and its manufacturing method have the following beneficial effects:

[0040] By forming a first tunnel oxide layer in the metal contact area and a second tunnel oxide layer in the non-metal contact area, the first tunnel oxide layer is formed in the metal contact area, the second tunnel oxide layer is formed in the non-metal contact area, and the thickness of the first tunnel oxide layer is less than the thickness of the second tunnel oxide layer. Since the metal contact area is the area corresponding to the electrode of the solar cell, the thickness of the first tunnel oxide layer covering the metal contact area is small, which reduces the metal recombination and contact resistance of the metal contact area and improves the efficiency of the solar cell.

[0041] On the other hand, by using the first laser to perform laser processing on the metal contact area to form a first tunnel oxide layer in the metal contact area; using the second laser to perform laser processing on the non-metal contact area to form a second tunnel oxide layer in the non-metal contact area, compared with the scheme of setting a mask and wet etching, by processing the metal contact area and the non-metal contact area with lasers of different powers, it is relatively easy to form the first tunnel oxide layer and the second tunnel oxide layer of different thicknesses, which can simplify the process and reduce costs. Compared with the scheme of using a mask method to form tunnel oxide layers of different thicknesses, which will damage the tunnel oxide layer, the first tunnel oxide layer and the second tunnel oxide layer formed by laser processing are dense and uniform, and there is no damage in the film layer, which is conducive to improving the stability of the process and improving the efficiency of solar cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] FIG1 is a schematic diagram of the structure of a solar cell provided in an embodiment of the present application;

[0043] FIG2 is a schematic diagram of a process of manufacturing a solar cell provided in an embodiment of the present application;

[0044] 3 is a schematic diagram of forming a polysilicon doped conductive layer on a substrate in a method for manufacturing a solar cell provided in an embodiment of the present application;

[0045] 4 is a schematic diagram of forming a first tunneling oxide layer and a second tunneling oxide layer on a substrate in a method for manufacturing a solar cell provided in an embodiment of the present application;

[0046] FIG. 5 is a schematic diagram of forming a polysilicon doped conductive layer in the method for manufacturing a solar cell provided in an embodiment of the present application.

[0047] Description of Figure Numbers:

[0048] 100. solar cell; 101. substrate;

[0049] 10. substrate; 20. first tunneling oxide layer; 30. second tunneling oxide layer; 50. polysilicon doped conductive layer; 60. doped conductive layer; 61. first oxide material layer; 71. first passivation layer; 72. second passivation layer; 81. first anti-reflection layer; 82. second anti-reflection layer; 91. first electrode; 92. second electrode;

[0050] F, first surface; S, second surface; C, side surface; J, metal contact area; H, non-metal contact area. DETAILED DESCRIPTION

[0051] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific embodiments disclosed below.

[0052] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0053] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0054] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0055] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0056] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are for illustrative purposes only and are not intended to be the only implementation method.

[0057] The solar cell of the embodiment of the present application is described below with reference to the accompanying drawings. In the present application, the solar cell is taken as a TOPCon cell as an example for description, and the solar cell can also be other types of cells, such as TBC, etc., and the case where the solar cell is other types is similar to this, which will not be repeated here.

[0058] FIG. 1 is a schematic diagram of the structure of a solar cell provided in an embodiment of the present application.

[0059] 1, the solar cell 100 provided in the embodiment of the present application includes a substrate 10. The substrate 10 may include a first surface Y and a second surface S arranged opposite to each other. The first surface Y of the substrate 10 includes a metal contact area J and a non-metal contact area H. The metal contact area J is an area that overlaps with the first electrode 91 on one side of the first surface Y of the solar cell when looking down at the solar cell 100. The non-metal contact area H is an area on the first surface other than the metal contact area J.

[0060] The solar cell 100 further includes a first tunnel oxide layer 20, a second tunnel oxide layer 30 and a polysilicon doped conductive layer 50, wherein the first tunnel oxide layer 20 is disposed in the metal contact region J, the second tunnel oxide layer 30 is disposed in the non-metal contact region H, and the first tunnel oxide layer 20 and the second tunnel oxide layer 30 may be adjacent to each other to form a whole layer of tunnel oxide layer together. The thickness of the first tunnel oxide layer 20 disposed in the metal contact region J is less than the thickness of the second tunnel oxide layer 30. The first tunnel oxide layer 20 and the second tunnel oxide layer 30 are formed separately in different process steps. The polysilicon doped conductive layer 50 is formed on the side of the first tunnel oxide layer 20 and the second tunnel oxide layer 30 away from the substrate 10.

[0061] By setting the first tunnel oxide layer 20 in the metal contact region J, and the second tunnel oxide layer 30 in the non-metal contact region H, and the thickness of the first tunnel oxide layer 20 is less than the thickness of the second tunnel oxide layer 30. Since the metal contact region J is a region corresponding to the electrode of the solar cell 100, the thickness of the first tunnel oxide layer 20 covered on the metal contact region J is small, which reduces the metal recombination and contact resistance of the metal contact region J, and improves the efficiency of the solar cell 100.

[0062] Furthermore, the solar cell 100 further includes a first passivation layer 71 , a second passivation layer 72 , a first anti-reflection layer 81 , a second anti-reflection layer 82 , a doped conductive layer 60 , a first electrode 91 , and a second electrode 92 .

[0063] The doped conductive layer 60 is disposed on the second surface S of the substrate 10. The doped conductive layer 60 is used to form a PN junction with the substrate 10. In the embodiment of the present application, the substrate 10 is an N-type substrate for example. At this time, the doped conductive layer 60 can be a P-type doped layer, for example, a boron-doped doped conductive layer 60 (also called a P+-type emitter). In addition, the doping type of the doped conductive layer 60 is opposite to the doping type of the polysilicon doped conductive layer 50.

[0064] The first passivation layer 71 and the first anti-reflection layer 81 are sequentially stacked on the surface of the polysilicon doped conductive layer 50 away from the substrate 10, and the second passivation layer 72 and the second anti-reflection layer 82 are sequentially stacked on the surface of the doped conductive layer 60 away from the substrate. The first passivation layer 71 and the second passivation layer 72 play a passivation role, and the first anti-reflection layer 81 and the second anti-reflection layer 82 play an anti-reflection role.

[0065] The first electrode 91 is disposed on the first anti-reflection layer 81 and is electrically connected to the polysilicon doped conductive layer 50 . The second electrode 92 is disposed on the second anti-reflection layer 82 and is electrically connected to the doped conductive layer 60 .

[0066] In the embodiment of the present application, the thickness of the first tunnel oxide layer 20 is 1.4 nm-1.6 nm; the thickness of the second tunnel oxide layer 30 is 1.5 nm-1.8 nm.

[0067] When the thickness of the first tunnel oxide layer 20 is less than 1.4 nm, the tunnel effect is poor and the carrier separation function cannot be achieved, resulting in poor passivation effect of the polysilicon doped conductive layer 50, thereby affecting the open circuit voltage of the solar cell 100. When the thickness of the first tunnel oxide layer 20 is greater than 1.6 nm, the contact resistance and fill factor of the first electrode are affected, thereby reducing the efficiency of the solar cell 100. Setting the thickness of the first tunnel oxide layer 20 to 1.4-1.6 nm can ensure the passivation effect and avoid the influence on the contact resistance, so that the efficiency of the solar cell 100 is higher.

[0068] Figure 2 is a schematic diagram of the process of the method for manufacturing a solar cell provided in an embodiment of the present application; Figure 3 is a schematic diagram of forming a polysilicon doped conductive layer on a substrate in the method for manufacturing a solar cell provided in an embodiment of the present application; Figure 4 is a schematic diagram of forming a first tunneling oxide layer and a second tunneling oxide layer on a substrate in the method for manufacturing a solar cell provided in an embodiment of the present application; Figure 5 is a schematic diagram of forming a polysilicon doped conductive layer in the method for manufacturing a solar cell provided in an embodiment of the present application.

[0069] 1 and 2 , a second aspect of the embodiments of the present application further provides a method for manufacturing a solar cell, which can manufacture the solar cell 100 as in the above embodiment.

[0070] The method for manufacturing a solar cell according to an embodiment of the present application includes:

[0071] S10, providing a substrate, wherein a first surface of the substrate includes a metal contact area and a non-metal contact area;

[0072] S20, laser processing the metal contact area with a first laser to form a first tunneling oxide layer in the metal contact area; laser processing the non-metal contact area with a second laser to form a second tunneling oxide layer in the non-metal contact area; wherein the power of the first laser is less than the power of the second laser, so that the thickness of the first tunneling oxide layer is less than the thickness of the second tunneling oxide layer;

[0073] S30, forming a polysilicon doped conductive layer on the side of the first tunnel oxide layer and the second tunnel oxide layer facing away from the substrate.

[0074] By forming a first tunnel oxide layer 20 in the metal contact area J and forming a second tunnel oxide layer 30 in the non-metal contact area H, the first tunnel oxide layer 20 is formed in the metal contact area J, the second tunnel oxide layer 30 is formed in the non-metal contact area H, and the thickness of the first tunnel oxide layer 20 is less than the thickness of the second tunnel oxide layer 30. Since the metal contact area J is the area corresponding to the electrode of the solar cell 100, the thickness of the first tunnel oxide layer 20 covered on the metal contact area J is small, which reduces the metal recombination and contact resistance of the metal contact area J and improves the efficiency of the solar cell 100.

[0075] On the other hand, by using the first laser to perform laser processing on the metal contact area J to form a first tunnel oxide layer 20 in the metal contact area J; using the second laser to perform laser processing on the non-metal contact area H to form a second tunnel oxide layer 30 in the non-metal contact area H, compared with the scheme of setting a mask and wet etching, by processing the metal contact area J and the non-metal contact area H with lasers of different powers, it is relatively easy to form the first tunnel oxide layer 20 and the second tunnel oxide layer 30 of different thicknesses, which can simplify the process and reduce costs. Compared with the scheme of using a mask method to form tunnel oxide layers of different thicknesses, which will damage the tunnel oxide layer, the first tunnel oxide layer 20 and the second tunnel oxide layer 30 formed by laser processing are dense and uniform, and there is no damage in the film layer, which is conducive to improving the stability of the process and improving the efficiency of the solar cell 100.

[0076] As mentioned above, the metal contact region J is the region corresponding to the electrode in the first surface F when the solar cell 100 is viewed from above, and the non-metal contact region H is the region other than the metal contact region J in the first surface F. In addition, the laser treatment here refers to laser oxidation, and a dense oxide layer is formed on the surface of the substrate 10 as the first tunneling oxide layer 20 and the second tunneling oxide layer 30 through laser oxidation. In addition, the metal contact region J and the non-metal contact region H are adjacent to each other, so the first tunneling oxide layer 20 and the second tunneling oxide layer 30 formed are also interconnected, for example, the second tunneling oxide layer 30 and the first tunneling oxide layer 20 are assembled into a whole layer of tunneling oxide layer.

[0077] In the embodiment of the present application, the power range of the first laser is 20W-40W, and the power range of the second laser is 40W-60W.

[0078] Such a configuration can form a dense and uniform first tunnel oxide layer 20 and a second tunnel oxide layer 30, and also facilitates the formation of a suitable thickness of the first tunnel oxide layer 20 and the second tunnel oxide layer 30. In specific implementation, the power range of the first laser can also be 25W, 30W, 35W. The power range of the second laser can also be 45W, 50W, 55W.

[0079] Further, in the step of laser processing the metal contact region J using the first laser to form the first tunnel oxide layer 20 in the metal contact region J, at least one of the following conditions is satisfied:

[0080] (1) The laser treatment using the first laser is performed in an air atmosphere;

[0081] (2) The type of the first laser is purple picosecond;

[0082] (3) The wavelength of the first laser is 355 nm;

[0083] (4) The spot size of the first laser is 200 μm x 200 μm;

[0084] (5) The scanning speed of the first laser is 10m / s-60m / s;

[0085] (6) The pulse frequency of the first laser is 200kHz-1000kHz;

[0086] (7) The power of the first laser is 30W.

[0087] Furthermore, in the step of laser processing the non-metallic contact region H using the second laser to form the second tunnel oxide layer 30 in the non-metallic contact region H, at least one of the following conditions is satisfied:

[0088] (1) The laser treatment using the second laser is performed in an air atmosphere;

[0089] (2) The type of the second laser is purple picosecond;

[0090] (3) The wavelength of the second laser is 355 nm;

[0091] (4) The spot size of the second laser is 200 μm x 200 μm;

[0092] (5) The scanning speed of the second laser is 10m / s-60m / s;

[0093] (6) The pulse frequency of the second laser is 200kHz-1000kHz;

[0094] (7) The power of the second laser is 45 W, 50 W, or 55 W.

[0095] In the embodiment of the present application, in step S30, after the step of forming the polysilicon doped conductive layer 50 on the side of the first tunnel oxide layer 20 and the second tunnel oxide layer 30 facing away from the substrate 10, the following step is further included:

[0096] A first passivation layer 71 and a first anti-reflection layer 81 are sequentially formed on a side of the polysilicon doped conductive layer 50 facing away from the substrate 10;

[0097] The first electrode 91 is formed on a portion of the first anti-reflection layer 81 covering the first tunnel oxide layer 20 , and the first electrode 91 is in ohmic contact with the polysilicon doped conductive layer 50 .

[0098] In this way, the first electrode 91 is arranged at a position corresponding to the first tunnel oxide layer 20 having a smaller thickness. In a specific implementation, the projection of the first tunnel oxide layer 20 on the first surface F may cover the projection of the first electrode 91 on the first surface F, so that the arrangement range of the first tunnel oxide layer 20 may be slightly larger than the arrangement range of the first electrode 91, or may be equal to the arrangement range of the first electrode 91, so as to ensure that the first electrode 91 can be directly opposite to the first tunnel oxide layer 20.

[0099] In the embodiment of the present application, before forming the first tunneling oxide layer 20 and the second tunneling oxide layer 30, the method for manufacturing a solar cell further includes:

[0100] A doped conductive layer 60 is formed on the second surface S of the substrate 10 . The doping type of the doped conductive layer 60 is opposite to that of the polysilicon doped conductive layer 50 . The second surface S is disposed opposite to the first surface F.

[0101] Further, referring to FIG. 1 and FIG. 3 , the substrate 10 further includes a plurality of side surfaces C adjacent to the first surface F and the second surface S; the step of forming the doped conductive layer 60 on the second surface S of the substrate 10 specifically includes:

[0102] Diffusion of a first doping element is performed on the second surface S of the substrate 10 to form a doped conductive material layer and a first oxide material layer 61 covering the surface of the doped conductive material layer on the second surface S of the substrate 10;

[0103] The first oxide material layer 61 plated on the first surface F and each side surface C is removed by a chain machine; and then the doped conductive material layer formed on the first surface F and each side surface C is removed by an alkaline etching solution.

[0104] In the embodiment of the present application, in step S30, the step of forming a polysilicon doped conductive layer 50 on the side of the first tunnel oxide layer 20 and the second tunnel oxide layer 30 away from the substrate 10 specifically includes:

[0105] An intrinsic amorphous silicon material layer is formed on the surface of the first tunnel oxide layer 20 and the second tunnel oxide layer 30 on the side facing away from the substrate 10, wherein the thickness of the intrinsic amorphous silicon material layer is 80-120 nm;

[0106] The intrinsic amorphous silicon material layer is diffused with a second doping element to form the intrinsic amorphous silicon material layer into a polysilicon doping material layer, and a second oxide material layer is formed on the surface of the polysilicon doping material layer; the second doping element is opposite to the doping type of the first doping element, and during the diffusion process, the junction temperature is 800° C.-920° C., and the junction time is 200s-2000s;

[0107] The second oxide material layer plated around the first surface F and the side surfaces C is removed by an acidic etching solution, the polysilicon doping material layer formed on the first surface F and the side surfaces C is removed, and the first oxide material layer 61 on the first surface F is removed.

[0108] The method for manufacturing the solar cell according to the embodiment of the present application is described below with reference to some specific examples.

[0109] Embodiment 1

[0110] The method for manufacturing a solar cell of this embodiment includes:

[0111] The first step: alkaline polishing and texturing of the n-type substrate 10 in a cleaning machine to remove a large number of recombination centers and mechanical damage on the surface; at the same time, a suede effect is given to the second surface S of the substrate 10 to reduce reflectivity.

[0112] Step 2: Place the substrate 10 in a diffusion furnace for diffusion. Specifically, perform boron diffusion on the second surface S of the substrate 10 to form a doped conductive material layer and form a PN junction with the substrate 10. The diffusion temperature is 850-1000°C for 10-30 minutes. The oxidation temperature is 900-1100°C for 60-120 minutes. After this step, a doped conductive material layer (not shown) and a first oxide material layer 61 covering the surface of the doped conductive material layer are formed on the second surface S of the substrate 10.

[0113] Step 3: Use a chain-type machine to remove the first oxide material layer 61 formed on the first surface F and the side surface C; then perform alkali polishing to remove the doped conductive material layer formed on the first surface F and the side surface C. As shown in FIG. 3 , a doped conductive layer 60 is formed on the second surface S of the substrate 10 .

[0114] Step 4: As shown in FIG4 , using a laser oxidation method, a first tunneling oxide layer 20 is formed in the metal contact area J of the first surface F by a first laser, and a second tunneling oxide layer 30 is formed in the non-metal contact area H by a second laser. The thickness of the first tunneling oxide layer is 1.4 nm-1.6 nm; the thickness of the second tunneling oxide layer is 1.5 nm-1.8 nm.

[0115] Among them, the laser processing using the first laser is carried out in an air atmosphere; the type of the first laser is purple picosecond; the wavelength of the first laser is 355nm; the spot size of the first laser is 200μmX200μm; the scanning speed of the first laser is 10m / s-60m / s; the pulse frequency of the first laser is 200kHz-1000kHz; the power of the first laser is 30W.

[0116] Furthermore, the laser processing using the second laser is carried out in an air atmosphere; the type of the second laser is purple picosecond; the wavelength of the second laser is 355nm; the spot size of the second laser is 200μmX200μm; the scanning speed of the second laser is 10m / s-60m / s; the pulse frequency of the second laser is 200kHz-1000kHz; the power of the second laser is 40W.

[0117] Step 5: Use LPCVD to prepare an intrinsic amorphous silicon material layer on the first tunnel oxide layer 20 and the second tunnel oxide layer 30, and the thickness of the intrinsic amorphous silicon material layer is 80-120nm. Then, phosphorus diffusion is performed in a tubular diffusion furnace, the push-in temperature is 800-920°C, and the push-in time is 200s-2000s. The intrinsic amorphous silicon material layer is formed into a polysilicon doped material layer, and a second oxide material layer is formed on the surface of the polysilicon doped material layer.

[0118] Step 6: Use an acidic etching solution to remove the second oxide material layer plated around one side of the first surface F and each side surface C, use RCA cleaning to remove the polysilicon doped material layer formed on one side of the first surface F and each side surface C, and remove the first oxide material layer 61 on one side of the first surface F, thereby forming a polysilicon doped conductive layer 50, as shown in Figure 5.

[0119] Step 7: A second passivation layer 72 and a second anti-reflection layer 82 are sequentially formed on the surface of the doped conductive layer 60, and then a first passivation layer 71 and a first anti-reflection layer 81 are sequentially deposited on the surface of the polysilicon doped conductive layer 50, a second electrode 92 is formed on the second anti-reflection layer 82, and a first electrode 91 is formed on the first anti-reflection layer 81 at a position corresponding to the first tunneling oxide layer, thereby forming a solar cell as shown in FIG. 1 .

[0120] Embodiment 2

[0121] The method for manufacturing the solar cell of this embodiment is similar to that of the first embodiment, except that the power of the second laser is 50W.

[0122] Embodiment 3

[0123] The method for manufacturing the solar cell of this embodiment is similar to that of the first embodiment, except that the power of the second laser is 60W.

[0124] Comparative Example 1

[0125] The first step: alkaline polishing and texturing of the n-type substrate in a cleaning machine to remove a large number of recombination centers and mechanical damage on the surface; at the same time, a suede effect is given to the second surface of the substrate to reduce reflectivity.

[0126] Step 2: Place the substrate into a diffusion furnace for diffusion to form a doped conductive layer on the second surface of the substrate.

[0127] Step 4: Using the LPCVD method, a whole tunnel oxide layer is formed on the first surface of the substrate by thermal oxidation.

[0128] Step 5: Prepare a polysilicon doped conductive layer on the tunneling oxide layer using LPCVD.

[0129] Step 6: forming a second passivation layer and a second anti-reflection layer in sequence on the surface of the doped conductive layer, and then depositing a first passivation layer and a first anti-reflection layer in sequence on the surface of the polysilicon doped conductive layer, forming a second electrode on the second anti-reflection layer, and forming a first electrode on the first anti-reflection layer.

[0130] The solar cells manufactured in Examples 1, 2, and 3 and the solar cell manufactured in Comparative Example 1 were subjected to cell performance tests, and the test results are recorded in Table 1.

[0131] Table 1

[0132]

[0133] It can be seen from the above experimental results that the solar cell prepared by the method of the present embodiment 1 has improved current density, open circuit voltage, fill factor, conversion efficiency, etc. compared with the comparative example 1. The solar cells prepared by the methods of the present embodiments 2 and 3 have the same current density, and improved open circuit voltage, fill factor, conversion efficiency, etc. compared with the comparative example 1.

[0134] It can be seen from this that the efficiency of the solar cell manufactured by the method of this embodiment is relatively high.

[0135] The embodiments of the present application also provide a photovoltaic module and a photovoltaic system. The photovoltaic module includes at least one battery string, and the battery string includes at least two solar cells 100 as described above, and the solar cells 100 can be connected together by serial welding.

[0136] The photovoltaic system includes the above-mentioned photovoltaic components. The photovoltaic system can be used in photovoltaic power stations, such as ground power stations, rooftop power stations, water power stations, etc. It can also be used in equipment or devices that use solar energy to generate electricity, such as user solar power supplies, solar street lights, solar cars, solar buildings, etc. Of course, it can be understood that the application scenarios of the photovoltaic system are not limited to this, that is to say, the photovoltaic system can be used in all fields that require solar energy to generate electricity. Taking the photovoltaic power generation system network as an example, the photovoltaic system may include a photovoltaic array, a junction box and an inverter. The photovoltaic array can be an array combination of multiple photovoltaic components. For example, multiple photovoltaic components can form multiple photovoltaic arrays. The photovoltaic array is connected to the junction box. The junction box can converge the current generated by the photovoltaic array. The converged current flows through the inverter and is converted into the alternating current required by the mains power grid. After that, it is connected to the mains network to realize solar power supply.

[0137] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0138] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A method for manufacturing a solar cell, characterized in that: include: Providing a substrate, wherein a first surface of the substrate comprises a metal contact area and a non-metal contact area; The metal contact region is laser-processed using a first laser to form a first tunneling oxide layer in the metal contact region; the non-metal contact region is laser-processed using a second laser to form a second tunneling oxide layer in the non-metal contact region; wherein the power of the first laser is less than the power of the second laser, so that the thickness of the first tunneling oxide layer is less than the thickness of the second tunneling oxide layer; A polysilicon doped conductive layer is formed on a side of the first tunnel oxide layer and the second tunnel oxide layer facing away from the substrate.

2. The method for manufacturing a solar cell according to claim 1, characterized in that: The power range of the first laser is 20W-40W, and the power range of the second laser is 40W-60W.

3. The method for manufacturing a solar cell according to claim 1, characterized in that: In the step of laser processing the metal contact region using the first laser to form a first tunnel oxide layer in the metal contact region, at least one of the following conditions is satisfied: (1) The laser treatment using the first laser is performed in an air atmosphere; (2) The type of the first laser is purple picosecond; (3) The wavelength of the first laser is 355 nm; (4) The spot size of the first laser is 200 μm×200 μm; (5) The scanning speed of the first laser is 10m / s-60m / s; (6) The pulse frequency of the first laser is 200kHz-1000kHz; (7) The power of the first laser is 30W.

4. The method for manufacturing a solar cell according to claim 1, characterized in that: In the step of laser processing the non-metallic contact area with a second laser to form a second tunneling oxide layer in the non-metallic contact area, at least one of the following conditions is satisfied: (1) The laser treatment using the second laser is performed in an air atmosphere; (2) The type of the second laser is purple picosecond; (3) The wavelength of the second laser is 355 nm; (4) The spot size of the second laser is 200 μm×200 μm; (5) The scanning speed of the second laser is 10m / s-60m / s; (6) The pulse frequency of the second laser is 200kHz-1000kHz; (7) The power of the second laser is 45 W, 50 W, or 55 W.

5. The method for manufacturing a solar cell according to claim 1, characterized in that: The thickness of the first tunnel oxide layer is 1.4 nm-1.6 nm; the thickness of the second tunnel oxide layer is 1.5 nm-1.8 nm.

6. The method for manufacturing a solar cell according to any one of claims 1 to 5, characterized in that: After the step of forming a polysilicon doped conductive layer on the side of the first tunnel oxide layer and the second tunnel oxide layer facing away from the substrate, the method further includes: forming a first passivation layer and a first anti-reflection layer in sequence on a side of the polysilicon-doped conductive layer away from the substrate; A first electrode is formed on a portion of the first anti-reflection layer covering the first tunneling oxide layer, and the first electrode is in ohmic contact with the polysilicon doped conductive layer.

7. The method for manufacturing a solar cell according to any one of claims 1 to 5, characterized in that: Before forming the first tunnel oxide layer and the second tunnel oxide layer, the method further includes: A doped conductive layer is fabricated on the second surface of the substrate, wherein the doped conductive layer has a doping type opposite to that of the polysilicon doped conductive layer, and the second surface is arranged opposite to the first surface.

8. The method for manufacturing a solar cell according to claim 7, characterized in that: The substrate further includes a plurality of side surfaces adjacent to the first surface and the second surface; The step of forming a doped conductive layer on the second surface of the substrate specifically includes: Diffusion of a first doping element is performed on the second surface of the substrate to form a doped conductive material layer and a first oxide material layer covering the surface of the doped conductive material layer on the second surface of the substrate; The first oxide material layer plated on the first surface and each of the side surfaces is removed by a chain machine; and the doped conductive material layer formed on the first surface and each of the side surfaces is removed by an alkaline etching solution.

9. The method for manufacturing a solar cell according to claim 8, characterized in that: The step of forming a polysilicon doped conductive layer on the first tunneling oxide layer and the second tunneling oxide layer on a side away from the substrate specifically includes: Forming an intrinsic amorphous silicon material layer on the surface of the first tunneling oxide layer and the second tunneling oxide layer on a side away from the substrate, wherein the thickness of the intrinsic amorphous silicon material layer is 80-120 nm; Diffusion of a second doping element is performed on the intrinsic amorphous silicon material layer to form the intrinsic amorphous silicon material layer into a polycrystalline silicon doping material layer, and a second oxide material layer is formed on the surface of the polycrystalline silicon doping material layer; the second doping element is opposite to the doping type of the first doping element, and during the diffusion process, the junction temperature is 800° C.-920° C., and the junction time is 200s-2000s; The second oxide material layer plated around the first surface and the side surfaces is removed by an acidic etching solution, the polysilicon doping material layer formed on the first surface and the side surfaces is removed, and the first oxide material layer on the first surface is removed.

10. A solar cell, characterized in that: The solar cell is manufactured by the manufacturing method of any one of claims 1 to 9.

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