Method and device for opening protective film layer on surface of substrate, preparation method of solar cell and photovoltaic module

Abstract

The embodiment of the invention provides a method and device for opening a protective film layer on the surface of a substrate, a preparation method of a solar cell and a photovoltaic module. The method for opening the protective film layer on the surface of the substrate comprises the steps that the substrate is obtained; controlling a laser emitting device to irradiate a first area of the protective film layer with a preset light spot; the laser emitting device is controlled to move in the first direction from the first area at a preset speed until film opening of the area, extending in the first direction, of the first area is completed; the next area where the laser emitting device moves from the first area in the first direction is a second area; the first region and the second region have a first overlapping region; the preset light spot comprises a second energy light area and a first energy light area; the energy of the first energy light area is lower than that of the second energy light area, and the first energy light area surrounds the second energy light area. According to the embodiment of the invention, thermal damage to the polycrystalline silicon layer can be reduced when the protective film layer on the polycrystalline silicon layer is removed.

Description

Technical Field

[0001] The present application relates to the field of laser processing, and in particular to a method and device for opening a protective film layer on a substrate surface, a method for preparing a solar cell, and a photovoltaic module. Background Art

[0002] In order to etch the polysilicon layer, it is necessary to use laser to ablate the protective film layer (PSG or BSG film) on the polysilicon layer, that is, to open the protective film layer.

[0003] In the process of using laser to open the protective film layer, the laser is irradiated in the form of a spot to the area that needs to be opened. When the laser moves from one spot to the next, there are overlapping areas. These overlapping areas are repeatedly irradiated, which will cause certain thermal damage to the polysilicon layer and affect the power generation efficiency of the manufactured solar cell.

[0004] It should be noted that the above content is not necessarily prior art, nor is it intended to limit the scope of patent protection of this application. Summary of the invention

[0005] The embodiments of the present application provide a method and device for opening a protective film layer on a substrate surface, a method for preparing a solar cell, and a photovoltaic module to solve or alleviate one or more of the technical problems raised above.

[0006] According to a first aspect of an embodiment of the present application, there is provided a method for opening a protective film layer on a surface of a substrate, comprising: Obtain a substrate; the substrate comprises a silicon wafer and a tunneling oxide layer, a polysilicon layer and a protective film layer stacked in sequence on the front side / back side of the silicon wafer; Controlling the laser emitting device to irradiate a first area of ​​the protective film layer with a preset light spot; the protective film layer includes a film opening area and a reserved area, and at least a part of the first area is located in the film opening area; Controlling the laser emitting device to move from the first area along the first direction at a preset speed, with the moving interval being adapted to the size of the first area along the first direction; until the film opening of the area extending along the first direction in the film opening area is completed; Among them, the next area where the laser emitting device moves from the first area along the first direction is the second area; the first area and the second area have a first overlapping area; the preset light spot includes the second energy light area and the first energy light area; the energy of the first energy light area is lower than the energy of the second energy light area, and the first energy light area surrounds the second energy light area; the shape of the second energy light area is square; the size of the first overlapping area is adapted to the size of the first energy light area.

[0007] Optionally, the first area includes a main area located in the film opening area, and a sub-area located in the reserved area; the size of the sub-area is adapted to the size of the first energy light zone.

[0008] Optionally, the laser energy of the first energy light zone is 40%-80% of that of the second energy light zone.

[0009] Optionally, the ring width of the first energy light zone in the first direction is 1 / 4-1 / 10 of the size of the second energy light zone in the first direction.

[0010] Optionally, the method for opening the protective film layer on the surface of the substrate also includes: controlling the laser emitting device to move to a third area adjacent to the first area in a second direction; the first area and the third area have a second overlapping area; the size of the second overlapping area is adapted to the size of the first energy light zone.

[0011] Optionally, the size of the first overlapping area is adapted to the size of the first energy light zone, including: The size of the first overlapping area in the first direction is adapted to the ring width of the first energy light zone in the first direction; The size of the second overlapping area is adapted to the size of the first energy light area, including: The size of the second overlapping area in the second direction is adapted to the ring width of the first energy light zone in the second direction.

[0012] Optionally, the ring width of the first energy light zone in the second direction is 1 / 4-1 / 10 of the size of the second energy light zone in the second direction.

[0013] According to a second aspect of the embodiment of the present application, there is provided a device for opening a protective film layer on a surface of a substrate, comprising: A laser emitting device, the laser emitting device comprising: a laser emitter, a diffractive optical element and a focusing lens; the laser emitter is used to emit laser light; the diffractive optical element is arranged near the emission outlet of the laser emitter; by configuring the diffraction parameters of the diffractive optical element, a preset light spot is formed after the laser passes through the diffractive optical element, the preset light spot comprises a first energy light zone and a second energy light zone, the energy of the first energy light zone is lower than the energy of the second energy light zone, and the first energy light zone surrounds the second energy light zone, and the shape of the second energy light zone is square; the focusing lens is arranged on the side of the diffractive optical element away from the laser emitter; by adjusting the distance between the focusing lens and the diffractive optical element, the size of the preset light spot can be adjusted; The supporting platform is used for supporting a substrate, and the surface of the substrate has a protective film layer to be opened.

[0014] A third aspect of the embodiments of the present application provides a method for preparing a solar cell, comprising: Obtain silicon wafers; A tunneling oxide layer, a polysilicon layer and a protective film layer are sequentially formed on the front and back sides of the silicon wafer to obtain a substrate; Adopting the method of any one of the above embodiments to remove the protective film layer on the surface of the substrate; The substrate after film cutting is completed is subjected to wet method to remove the polysilicon layer; Diffusion of boron is performed on the front side of the substrate to obtain a front emitter; Phosphorus is diffused on the back side of the substrate to obtain a phosphorus-doped polysilicon layer.

[0015] According to a fourth aspect of the embodiments of the present application, a photovoltaic module is provided, comprising: at least one battery string, the battery string comprising at least two solar cells, the solar cells being manufactured by the method for manufacturing a solar cell according to any of the above embodiments. The embodiment of the present application adopts the above technical solution, and the first overlapping area that needs to be repeatedly processed is processed by using the first energy light zone with lower energy to reduce the thermal damage to the polysilicon layer. Thermal damage can cause the displacement of crystal atoms and form lattice dislocation defects, thereby affecting the photoelectric conversion efficiency of the battery. BRIEF DESCRIPTION OF THE DRAWINGS In the accompanying drawings, unless otherwise specified, the same reference numerals throughout the multiple drawings represent the same or similar parts or elements. These drawings are not necessarily drawn to scale. It should be understood that these drawings only depict some embodiments disclosed in the present application and should not be regarded as limiting the scope of the present application.

[0016] Figure 1 A schematic flow chart of a method for removing a protective film layer on a substrate surface provided in one embodiment of the present application is shown.

[0017] Figure 2 A schematic diagram of a protective film layer of a polysilicon layer according to an embodiment of the present application is shown.

[0018] Figure 3 A schematic diagram showing the light spot effect of a preset light spot in an embodiment of the present application is shown.

[0019] Figure 4 A schematic diagram showing a laser spot irradiation of a film opening area with a preset light spot in an embodiment of the present application.

[0020] Figure 5 A schematic flow chart of a method for opening a protective film layer on a substrate surface according to another embodiment of the present application is shown.

[0021] Figure 6 A schematic structural diagram of a laser emitting device provided in an embodiment of the present application is shown.

[0022] Figure 7A schematic flow chart showing a method for preparing a solar cell according to an embodiment of the present application is shown. DETAILED DESCRIPTION

[0023] In the following, only some exemplary embodiments are briefly described. As those skilled in the art will appreciate, the described embodiments may be modified in various ways without departing from the spirit or scope of the present application. Therefore, the drawings and descriptions are considered to be exemplary and non-restrictive in nature.

[0024] Passivated contact solar cells, such as tunnel oxide passivated contact (TOPCon) solar cells, can make the photovoltaic conversion efficiency of the cells exceed 25%. It is the mainstream technology of the next generation of large-scale film production revolution after PERC (Passivated Emitter and Rear Cell, emitter and rear passivated cell) cells. TOPCon cells are ushering in an explosive period of expansion due to their cost-effective advantages. Among them, in TOPCon cells, the use of double-sided polysilicon passivation technology can achieve a photovoltaic conversion efficiency of 28.7%.

[0025] Double-sided polysilicon passivation technology includes using laser film opening to remove the protective film layer on some areas of the polysilicon layer surface. The protective film layer can be PSG (Phosphosilicate Glass) or BSG (Borosilicate Glass) film, and then using wet method to etch the opened area. In the process of using laser to open the protective film layer, how to reduce the thermal damage to the polysilicon layer is one of the difficulties.

[0026] Based on this, an embodiment of the present application provides a method for opening a protective film layer on a surface of a substrate. Figure 1 The schematic diagram of the process of opening the protective film layer on the surface of the substrate according to one embodiment of the present application is shown. Figure 1 As shown, the method for opening the protective film layer on the surface of the substrate includes: S110, obtaining a substrate, the substrate comprising a silicon wafer and a tunneling oxide layer, a polysilicon layer and a protective film layer sequentially stacked on the front side / back side of the silicon wafer.

[0027] S120, controlling the laser emitting device to irradiate the first area of ​​the protective film layer with a preset light spot.

[0028] Figure 2 Schematic diagram of the protective film layer on the surface of the substrate of the present application embodiment is shown. Figure 2 As shown, the protective film layer 100 includes a film opening area 120 and a reserved area 110 , and at least a portion of the first area 121 is located in the film opening area 120 .

[0029] The protective film layer 100 refers to a film layer located on the surface of the substrate, and a polysilicon layer is also included between the substrate and the protective film layer 100. The protective film layer 100 may be located on the surface of the polysilicon layer, and may protect the polysilicon layer. The protective film layer may be a PSG film or a BSG film. The PSG film may be formed by spin coating a tetraethyl silicate or triethyl phosphate solution on the polysilicon layer. The BSG film may be formed by spin coating a tetraethyl silicate or triethyl borate solution on the polysilicon layer. The protective film layer may protect the polysilicon layer from being etched. When the polysilicon layer needs to be etched, the protective film layer needs to be opened by laser mold opening.

[0030] The method for opening the protective film layer on the surface of the substrate in the embodiment of the present application is used to prepare a selective polysilicon passivation structure. The protective film layer on the surface of the substrate is removed by opening the protective film layer on the surface of the substrate to facilitate subsequent etching of the portion of the area where the protective film layer is removed, thereby forming a selective polysilicon passivation structure.

[0031] The protective film layer 100 includes a film opening area 120 and a reserved area 110. The film opening area 120 is the area where the protective film layer needs to be removed, and the reserved area 110 is the area of ​​the protective film layer 100 other than the film opening area 120, that is, the area where the film does not need to be opened.

[0032] At least a portion of the first region 121 is located in the film opening region 120 , so that the laser can be irradiated from the first region 121 to remove the protective film layer of the first region 121 located in the film opening region 120 .

[0033] S130, controlling the laser emitting device to move from the first area along the first direction at a preset speed, with the moving interval being adapted to the size of the first area along the first direction; until the film opening of the area extending along the first direction in the film opening area is completed.

[0034] like Figure 2 As shown, the first area 121 can be an area in the film opening area 120 that is close to the first edge position of the film opening area 120, and the first direction can be a direction from the first edge position toward a second edge position opposite to the first edge position, so that the laser emitting device moves from the first edge position toward the second edge position to complete the film opening at multiple positions in the film opening area 120.

[0035] The preset speed can be determined according to the need for film opening and the time required for the laser emitted by the laser emitting device to irradiate the first area 121. For example, if the laser irradiates the first area 121 for 0.1s to complete the film opening, the laser moves to the next area when the time for irradiating the first area 121 reaches 0.1s.

[0036] The moving pitch is adapted to the size of the first region 121 along the first direction, and the moving pitch may be equal to the size of the first region 121 in the first direction, or the moving pitch may be smaller than the size of the first region 121 in the first direction.

[0037] In an example, the first direction may be the length direction of the first region 121, and the length of the first region 121 is 100 μm. After irradiating the first region 121, the laser emitting device may move 80 μm along the length direction, and after irradiation, move 80 μm along the length direction and away from the first region; until the film opening in the film opening area in the length direction of the first region 121 is completed.

[0038] In the embodiment of the present application, the next area to which the laser emitting device moves from the first area 121 along the first direction is the second area 122 ; the first area 121 and the second area 122 have a first overlapping area 1210 .

[0039] In the above example, the length of the first region 121 is 100 μm; the second region 122 is moved 80 μm along the length direction based on the side of the first region 121 away from the second region 122; the spot size of the laser remains unchanged, and the length of the second region 122 is 100 μm, then the first region 121 and the second region 122 have a first overlapping region 1210 with a length of 20 μm.

[0040] Figure 3 A schematic diagram showing the light spot effect of the preset light spot of the embodiment of the present application is shown as follows: Figures 2 to 3 As shown, the preset light spot 200 of the embodiment of the present application includes a second energy light zone 210 and a first energy light zone 220; the energy of the first energy light zone 220 is lower than the energy of the second energy light zone 210, and the first energy light zone 220 surrounds the second energy light zone 210; the shape of the second energy light zone 210 is square; the size of the first overlapping area 1210 is adapted to the size of the first energy light zone 220.

[0041] The second energy light zone 210 may refer to an area with higher laser energy, and similarly, the first energy light zone 220 may refer to an area with lower laser energy. When the second energy light zone 210 is irradiated on the film opening area 120, the film opening can be completed by irradiating once. When the first energy light zone 220 is irradiated on the film opening area 120, it needs to be irradiated twice or more to complete the film opening.

[0042] The second energy light zone 210 is square in shape, so that when the laser moves from the first area 121 to the second area 122, the light spots can be seamlessly connected to ensure that the film layer in the film opening area 120 is removed without omission, thereby improving the effectiveness of laser film opening.

[0043] The size of the first overlapping area 1210 is adapted to the size of the first energy light zone 220 , and the size of the first overlapping area 1210 may be equal to the size of the first energy light zone 220 .

[0044] Figure 4 A schematic diagram of the laser spot irradiation of the film opening area with a preset light spot according to the embodiment of the present application is shown. Figure 4 As shown, the preset light spot starts from the first area 121, moves along the first direction or the second direction, and moves to the next area (the second area 122) at a preset speed. The first energy light zone 220 is repeatedly irradiated so that the first overlapping area 1210 completes the film opening, and the area irradiated by the second energy light zone 210 can complete the film opening after one irradiation.

[0045] In an embodiment of the present application, the protective film in the film-opening area on the surface of the polysilicon layer is removed, and then a liquid that can etch polysilicon is coated on the film-opening area by wet coating. The liquid acts on the polysilicon in the film-opening area to form a selective polysilicon passivation structure.

[0046] In the embodiment of the present application, the first overlapping area 1210 that needs to be repeatedly processed can be processed by using the first energy light zone 220 with lower energy to reduce thermal damage to the polysilicon layer. Thermal damage can cause the displacement of crystal atoms and form lattice dislocation defects, thereby affecting the photoelectric conversion efficiency of the battery. In one embodiment, the first region 121 includes a main region located in the film opening region 120 , and a sub-region located in the reserved region 110 ; the size of the sub-region is adapted to the size of the first energy light region 220 .

[0047] Since the film opening area 120 has a boundary, and the first area 121 is entirely located in the film opening area 120, when the first energy light zone 220 of the preset light spot irradiates the first area 121, the portion close to the boundary is only irradiated by the first energy light zone once, and film opening cannot be achieved. Therefore, by setting the first area 121 between the film opening area 120 and the reserved area 110, the portion that can only be irradiated by the first energy light zone 220 once is set in the reserved area 110, so that the film opening can be completed in all areas that need to be opened.

[0048] In one example, if Figure 2 As shown, the film opening area 120 is a rectangular area with a rectangular boundary. The main area of ​​the first area 121 is located in the film opening area 120. Other areas extending from the first area 121 along the first direction or the second direction also have a main area located in the film opening area 120 and a secondary area located in the retained area 110. The size of the secondary area is adapted to the size of the first energy light zone 220.

[0049] When the laser irradiates the first area 121 of the protective film layer, the second energy light zone 210 irradiates the main area of ​​the first area 121, and the first energy light zone 220 irradiates the sub-area of ​​the first area 121. The size of the sub-area is adapted to the size of the first energy light zone 220, so that the first energy light zone 220 irradiates the sub-area of ​​the first area 121, and the film will not be opened due to the one-time irradiation of the first energy light zone 220.

[0050] In one embodiment, the laser energy of the first energy light zone 220 is 40%-80% of that of the second energy light zone 210 .

[0051] Preferably, the laser energy of the first energy light zone 220 is 40%-50% of that of the second energy light zone 210 .

[0052] For example, when a nanosecond laser pulse with a wavelength of 532nm is used to irradiate a BSG film layer with a thickness of 1μm at a repetition frequency of 100Hz, the laser can remove the protective film without damaging the polysilicon layer. The energy range is 300-500 microjoules (μJ). The energy of the second energy light zone 210 can be configured to be 500μJ and the energy of the first energy light zone to be 250μJ.

[0053] For another example, the energy of the second energy light zone 210 may be configured to be 300 μJ, and the energy of the first energy light zone 220 may be configured to be 20 μJ.

[0054] In one embodiment, the ring width of the first energy light zone 220 in the first direction is 1 / 4-1 / 10 of the size of the second energy light zone 210 in the first direction.

[0055] In the embodiment of the present application, the first direction is the length direction of the first region 121 or the second energy light zone 210 , and the ring width of the first energy light zone 220 in the first direction is 1 / 4-1 / 10 of the length of the second energy light zone 210 .

[0056] Exemplarily, the length of the second energy light zone 210 is 200 μm, and the ring width of the first energy light zone 220 in the length direction is 50 μm.

[0057] In one example, the ring width of the first energy light zone 220 in the first direction is 1 / 10 of the size of the second energy light zone 210 in the first direction. By reducing the area of ​​the low energy zone, the film opening speed can be accelerated and the area for multiple film openings can be reduced.

[0058] In one example, when the width of the first region 121 is equal to the width of the film opening region 120 , the film is opened along the first direction, and the film opening of the film opening region is completed.

[0059] Figure 5A schematic diagram showing a process of opening a protective film layer on a substrate surface according to another embodiment of the present application. Figure 5 As shown, the method for opening the protective film layer on the surface of the substrate in the embodiment of the present application further includes: S140, controlling the laser emitting device to move to a third area adjacent to the first area in the second direction.

[0060] The second direction can be the width direction of the first area. For example, if the width of the first area is 30 μm, the laser emitting device can move 25 μm along the width direction after irradiating the first area. After irradiation, it can move 25 μm along the width direction and away from the first area until the film opening in the film opening area in the width direction of the first area is completed.

[0061] The first area and the third area have a second overlapping area; the size of the second overlapping area is adapted to the size of the first energy light area.

[0062] The size of the second overlapping area is adapted to the size of the first energy light area, and the size of the second overlapping area may be equal to the size of the first energy light area.

[0063] In one embodiment, if Figure 5 As shown, the method for opening the protective film layer on the surface of the substrate in the embodiment of the present application may also include: S150, controlling the laser emitting device to move from the third area along the first direction at a preset speed, with the moving interval being adapted to the size of the third area along the first direction; until the film opening of the area extending along the first direction in the third area is completed.

[0064] S160, controlling the laser emitting device to move successively to other areas of the first area in the second direction, and then completing the areas of other areas extending along the first direction, until the film opening of all the film opening areas is completed.

[0065] In the embodiment of the present application, the film is opened gradually in multiple areas of the film opening area, for example, from left to right and then from top to bottom.

[0066] In one example, the film opening area is a rectangular area, and the film opening of the film opening area is gradually performed from left to right and then from top to bottom in the above manner, so that the film opening of the film opening area is completed.

[0067] In one example, if the film opening area is an irregular area, a rectangular area can be determined first. The rectangular area is within the film opening area, and the film is opened in the rectangular area first; then the size of the light spot is adjusted to open the film in the area outside the rectangular area within the film opening area. To open the film in the area outside the rectangular area within the film opening area, the size of the light spot can be adjusted in a trial manner; for example, a largest rectangular area is determined first to open the film in the rectangular area; then the largest rectangular area is determined in the remaining areas, and then the film is opened. The rectangular area can be adapted to the size of the light spot. By dividing the film opening area into the largest rectangular area and other areas, the film opening of any irregular shape of the film opening area can be completed, providing a variety of application scenarios for the method of opening the protective film layer on the surface of the substrate.

[0068] In one embodiment, the size of the first overlapping area is adapted to the size of the first energy light zone, including: the size of the first overlapping area in the first direction is adapted to the ring width of the first energy light zone in the first direction.

[0069] For example, the size (such as length) of the first overlapping area in the first direction may be equal to the ring width of the first energy light zone in the first direction, and the size (such as width) of the first overlapping area in the second direction may be equal to the width of the first energy light zone.

[0070] In one embodiment, the size of the second overlapping area is adapted to the size of the first energy light zone, including: the size of the second overlapping area in the second direction is adapted to the ring width of the first energy light zone in the second direction.

[0071] For example, the size (eg, width) of the second overlapping area in the second direction may be equal to the ring width of the first energy light zone in the second direction, and the size (eg, length) of the second overlapping area in the first direction may be equal to the length of the first energy light zone.

[0072] In the above example, the length is the dimension in the first direction, and the width is the dimension in the second direction.

[0073] In one embodiment, the ring width of the first energy light zone in the second direction is 1 / 4-1 / 10 of the size of the second energy light zone in the second direction.

[0074] Exemplarily, the width of the second energy light zone is 32 μm, and the ring width of the first energy light zone in the width direction is 8 μm.

[0075] The ring width of the first energy light zone in the second direction may be unequal to the ring width in the first direction.

[0076] The embodiment of the present application also provides a device for opening a protective film layer on a surface of a substrate, comprising a laser emitting device and a supporting platform. Figure 6FIG. 1 is a schematic diagram showing the structure of a laser emitting device provided in an embodiment of the present application. Figure 6 As shown, the laser emitting device includes: a laser emitter 300, a diffractive optical element 400 and a focusing lens 500. A carrier (not shown) is used to carry a substrate, and the substrate has a protective film layer to be opened. The laser emitted by the laser emitting device acts on the protective film layer on the surface of the substrate on the carrier, thereby realizing the laser opening of the protective film layer.

[0077] The laser emitter 300 is used to emit laser light.

[0078] The diffraction optical element 400 is arranged near the emission outlet of the laser emitter 300; by configuring the diffraction parameters of the diffraction optical element 400, after the laser passes through the diffraction optical element 400, a preset light spot 200 having a first energy light zone and a second energy light zone is formed, and the first energy light zone surrounds the second energy light zone, and the shape of the second energy light zone is a square.

[0079] The focusing lens 500 is disposed on a side of the diffractive optical element 400 away from the laser emitter 300 ; the size of the preset light spot 200 can be adjusted by adjusting the distance between the focusing lens 500 and the diffractive optical element 400 .

[0080] In the embodiment of the present application, the diffractive optical element 400 is an optical element 400 that uses the light diffraction phenomenon to change the shape and distribution of the light beam. The diffractive optical element 400 has a two-dimensionally distributed microstructure inside, and the light spot 200 of the specified requirement is formed by configuring the layout of the microstructure and the diffraction parameters.

[0081] A corresponding diffractive optical element 400 can be configured based on the preset light spot 200 , and multiple diffraction parameters of the diffractive optical element 400 are adapted to the preset light spot 200 , so that after the laser passes through the diffractive optical element 400 , the preset light spot 200 can be generated to open the film based on the preset light spot 200 .

[0082] In the embodiment of the present application, the size of the preset light spot 200 is adjusted by adjusting the distance between the focusing lens 500 and the diffractive optical element 400, so that the film is opened with the light spot 200 of the predetermined size.

[0083] The embodiment of the present application also provides a method for preparing a solar cell. Figure 7 The schematic diagram of the process of manufacturing a solar cell according to an embodiment of the present application is shown. Figure 7 As shown, the method for preparing the solar cell comprises: S710, obtaining a silicon wafer.

[0084] S720, sequentially forming a tunneling oxide layer, a polysilicon layer, and a protective film layer on the front and back sides of the silicon wafer to obtain a substrate; S730, opening the protective film layer on the surface of the substrate. The protective film layer on the surface of the substrate is opened by using the method for opening the protective film layer on the surface of the substrate in any of the above-mentioned embodiments.

[0085] S740, the substrate after film cutting is completed, and the polysilicon layer is removed by a wet method; S750, performing boron diffusion on the front side of the substrate to obtain a front emitter; S760, phosphorus is diffused on the back side of the substrate to obtain a phosphorus-doped polysilicon layer.

[0086] The method for preparing the solar cell also includes other steps such as pickling the protective film layer and preparing the grid line, which will not be described in detail here.

[0087] The embodiments of the present application may also provide a photovoltaic assembly, including at least one battery string, the battery string including at least two solar cells, and the solar cells are manufactured using the method for manufacturing solar cells of any of the above embodiments. The embodiment of the present application can also provide a photovoltaic system, including photovoltaic components of any of the above embodiments. The advantages of the above photovoltaic components are also possessed by the photovoltaic system, which will not be repeated here. The above photovoltaic system has a wide range of applications, not only limited to photovoltaic power stations, such as ground power stations, rooftop power stations and water power stations, but also includes various equipment and devices that use solar energy to generate electricity, such as user solar power supplies, solar street lights, solar cars and solar buildings. 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 where solar energy is required for power generation. 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 may be an array combination of multiple photovoltaic components. For example, multiple photovoltaic components may form multiple photovoltaic arrays. The photovoltaic array is connected to a 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, and then connected to the mains network to realize solar power supply.

[0088] It should be noted 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", etc. are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. The orientation words "inside" and "outside" refer to the inside and outside relative to the outline of each component itself. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Therefore, the exemplary term "above..." can include both "above..." and "below..." orientations. The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used here are interpreted accordingly.

[0089] It should also be noted that "one embodiment", "another embodiment", "embodiment", etc. mentioned in this application refer to the specific features, structures or characteristics described in conjunction with the embodiment included in at least one embodiment generally described in this application. The same expression appearing in multiple places in the specification does not necessarily refer to the same embodiment. Further, when a specific feature, structure or characteristic is described in conjunction with any embodiment, it is claimed that the realization of such feature, structure or characteristic in conjunction with other embodiments also falls within the scope of this application.

[0090] In the above embodiments, examples of the embodiments are shown in the accompanying drawings. In the accompanying drawings, for clarity, the sizes of layers, regions, elements and their relative sizes may be exaggerated. The same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as limitations on the present application. It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0091] It should be understood that when an element or layer is referred to as being "on," "adjacent to," "connected to," or "coupled to" another element or layer, it can be directly on, adjacent to, connected to, or coupled to the other element or layer, or there may be intervening elements or layers. In contrast, when an element is referred to as being "directly on," "directly adjacent to," "directly connected to," or "directly coupled to" another element or layer, there are no intervening elements or layers.

[0092] It should be understood that although the terms first, second, third, etc. can be used to describe various elements, components, regions, layers and / or parts, these elements, components, regions, layers and / or parts should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or part from another element, component, region, layer or part. When the second element, component, region, layer or part is discussed, it does not mean that the present disclosure necessarily has the first element, component, region, layer or part.

[0093] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, "connection" 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 this application can be understood according to specific circumstances.

[0094] It should be noted that the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or apparatus comprising a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to these processes, methods, products or apparatuses.

[0095] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0096] It should also be noted that the above are only preferred embodiments of the present application, and the patent protection scope of the present application is not limited thereto. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly used in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A method for opening a protective film layer on a substrate surface, characterized in that: include: Obtaining a substrate; The substrate comprises a silicon wafer and a tunneling oxide layer, a polysilicon layer and a protective film layer stacked in sequence on the front side / back side of the silicon wafer; Controlling the laser emitting device to irradiate a first area of ​​the protective film layer with a preset light spot; the protective film layer includes a film opening area and a reserved area, and at least a part of the first area is located in the film opening area; Controlling the laser emitting device to move from the first area along the first direction at a preset speed, with the moving interval being adapted to the size of the first area along the first direction; Until the film opening of the area of ​​the first area extending along the first direction in the film opening area is completed; Among them, the next area where the laser emitting device moves from the first area along the first direction is the second area; the first area and the second area have a first overlapping area; the preset light spot includes a second energy light zone and a first energy light zone; the energy of the first energy light zone is lower than the energy of the second energy light zone, and the first energy light zone surrounds the second energy light zone; the shape of the second energy light zone is square; the size of the first overlapping area is adapted to the size of the first energy light zone.

2. The method according to claim 1, characterized in that The first area includes a main area located in the film opening area and a sub-area located in the reserved area; the size of the sub-area is adapted to the size of the first energy light area.

3. The method according to claim 1, characterized in that The laser energy in the first energy light zone is 40%-80% of that in the second energy light zone.

4. The method according to claim 1, characterized in that: The ring width of the first energy light zone in the first direction is 1 / 4-1 / 10 of the size of the second energy light zone in the first direction.

5. The method according to claim 1, characterized in that Also includes: Controlling the laser emitting device to move to a third area adjacent to the first area in the second direction; The first area and the third area have a second overlapping area; the size of the second overlapping area is adapted to the size of the first energy light area.

6. The method according to claim 5, characterized in that The size of the first overlapping area is adapted to the size of the first energy light zone, including: The size of the first overlapping area in the first direction is adapted to the ring width of the first energy light zone in the first direction; The size of the second overlapping area is adapted to the size of the first energy light area, including: The size of the second overlapping area in the second direction is adapted to the ring width of the first energy light zone in the second direction.

7. The method according to claim 6, characterized in that The ring width of the first energy light zone in the second direction is 1 / 4-1 / 10 of the size of the second energy light zone in the second direction.

8. A device for opening a protective film layer on a substrate surface, characterized in that: include: A laser emitting device, the laser emitting device comprising: a laser emitter, a diffractive optical element and a focusing lens; the laser emitter is used to emit laser light; the diffractive optical element is arranged near the emission outlet of the laser emitter; by configuring the diffraction parameters of the diffractive optical element, the laser forms a preset light spot after passing through the diffractive optical element, the preset light spot comprises a first energy light zone and a second energy light zone, the energy of the first energy light zone is lower than the energy of the second energy light zone, and the first energy light zone surrounds the second energy light zone, and the shape of the second energy light zone is square; the focusing lens is arranged on the side of the diffractive optical element away from the laser emitter; by adjusting the distance between the focusing lens and the diffractive optical element, the size of the preset light spot can be adjusted; The supporting platform is used for supporting a substrate, and the surface of the substrate has a protective film layer to be opened.

9. A method for preparing a solar cell, characterized in that: include: Obtain silicon wafers; Sequentially forming a tunneling oxide layer, a polysilicon layer and a protective film layer on the front and back sides of the silicon wafer to obtain a substrate; Adopting the method described in any one of claims 1 to 7 to open the protective film layer of the substrate; The substrate after film opening is completed, and the polysilicon layer is removed by a wet method; Performing boron diffusion on the front side of the substrate to obtain a front emitter; Phosphorus is diffused on the back side of the substrate to obtain a phosphorus-doped polysilicon layer.

10. A photovoltaic module, characterized in that: include: At least one battery string, the battery string comprising at least two solar cells, the solar cells being manufactured by the method for manufacturing solar cells as claimed in claim 9.

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