Photovoltaic cell, preparation method thereof and laminated cell

Abstract

The embodiment of the invention relates to the photovoltaic field, and provides a photovoltaic cell and a preparation method thereof, and a laminated cell, and the preparation method comprises the steps: providing an initial photovoltaic cell, the first surface of which comprises a first laser region and a first non-laser region, and the second surface of which comprises a second laser region and a second non-laser region; the first doped film, the first functional film, the second doped film and the second functional film sequentially cover the first surface, and the tunneling film, the passivation film and the third functional film sequentially cover the second surface. Meanwhile, a laser treatment process is adopted on the first surface and the second surface, at least the part, located in the first laser area, of the second functional film is converted into a first laser part, and the part, located in the second laser area, of the third functional film is converted into a second laser part; and removing the second functional film, the second doped film, the first functional film, the third functional film, the first doped film located in the first laser region and the passive film and the tunneling film located in the second laser region by adopting an etching process, thereby at least facilitating simplification of the process steps of preparing the photovoltaic cell.

Description

Technical Field

[0001] The embodiments of the present disclosure relate to the photovoltaic field, and in particular to a photovoltaic cell and a preparation method thereof, and a laminated cell. Background Art

[0002] At present, with the gradual depletion of fossil energy, photovoltaic cells are becoming more and more widely used as a new energy alternative. Photovoltaic cells are devices that convert sunlight into electrical energy. Photovoltaic cells use the principle of photovoltaics to generate carriers, and then use electrodes to lead the carriers out, thereby facilitating the effective use of electrical energy.

[0003] The current photovoltaic cells mainly include IBC cells (Interdigitated Back Contact), TOPCON (Tunnel Oxide Passivated Contact), PERC cells (Passivated emitter and real cell) and heterojunction cells, etc. The photoelectric conversion efficiency of solar cells is improved by reducing optical losses and reducing the recombination of photogenerated carriers on the surface and in the body of the silicon substrate through different film layer settings and functional limitations.

[0004] However, forming various film layers in photovoltaic cells involves numerous steps such as deposition, etching, and cleaning, which affects the preparation efficiency of photovoltaic cells. Summary of the invention

[0005] The embodiments of the present disclosure provide a photovoltaic cell and a method for preparing the same, and a stacked cell, which are at least helpful in simplifying the process steps for preparing the photovoltaic cell.

[0006] According to some embodiments of the present disclosure, on one hand, an embodiment of the present disclosure provides a method for preparing a photovoltaic cell, comprising: providing an initial photovoltaic cell, the initial photovoltaic cell comprising: a crystalline silicon substrate, the crystalline silicon substrate having a first surface and a second surface opposite to each other along a first direction, the first surface comprising a first laser area and a first non-laser area alternately arranged along a second direction, the second surface comprising a second laser area and a second non-laser area alternately arranged along the second direction; a first doped film, a first functional film, a second doped film, and a second functional film covering the first surface and stacked along the first direction, a tunneling film, a passivation film, and a third functional film covering the second surface and stacked in a direction opposite to the first direction; and at the same time, The second surface is processed by a laser treatment process to process the portion of the initial photovoltaic cell located in the first laser area and the portion of the second laser area, so that at least the portion of the second functional film located in the first laser area is transformed into the first laser part, and the portion of the third functional film located in the second laser area is transformed into the second laser part; the second functional film, the second doped film, the first functional film and the third functional film are removed by an etching process, the first doped film located in the first laser area is removed and the first doped film remains as an emitter, and the passivation film and the tunneling film located in the second laser area are removed, and the passivation film remains as a passivation layer, and the tunneling film remains as a tunneling layer.

[0007] In some embodiments, an orthographic projection area of ​​the first laser zone on the first surface is different from an orthographic projection area of ​​the second laser zone on the first surface, and / or an orthographic projection of the first laser zone on the first surface only partially overlaps or does not overlap with an orthographic projection of the second laser zone on the first surface.

[0008] In some embodiments, the step of simultaneously applying the laser processing process to the first surface and the second surface includes: applying a first laser processing process to the first surface and applying a second laser processing process to the second surface, and the first laser processing process and the second laser processing process are performed simultaneously; wherein at least one of the laser action time, laser power, laser wavelength, laser spot size or laser scanning speed used in the first laser processing process and the second laser processing process is different.

[0009] In some embodiments, the step of using the first laser processing process on the first surface includes: using a first laser action time, a first laser power, a first laser wavelength, a first laser spot size and a first laser scanning speed to process the portion of the initial photovoltaic cell located in the first laser area; the step of using the second laser processing process on the second surface includes: using a second laser action time, a second laser power, a second laser wavelength, a second laser spot size and a second laser scanning speed to process the portion of the initial photovoltaic cell located in the second laser area; wherein, the first laser action time is greater than the second laser action time; and / or, the first laser power is greater than the second laser power; and / or, the first laser spot size is greater than the second laser spot size; and the first laser wavelength is less than the second laser wavelength.

[0010] In some embodiments, in the step of applying the first laser processing process to the first surface, only the portion of the second functional film located in the first laser area is transformed into the first laser portion; or, the portion of the second functional film located in the first laser area is transformed into the first laser portion, and the portion of the second doped film located in the first laser area is transformed into the third laser portion; in the step of applying the second laser processing process to the second surface, only the portion of the third functional film located in the second laser area is transformed into the second laser portion; or, the portion of the third functional film located in the second laser area is transformed into the second laser portion, and the portion of the passivation film located in the second laser area is transformed into the fourth laser portion.

[0011] In some embodiments, in the step of adopting a stacked first laser processing process on the first surface: a first laser emitter is used to emit a first laser; in the step of adopting the second laser processing process on the second surface: a second laser emitter is used to emit a second laser; the first surface has a first side and a second side relative to each other along the second direction, the second surface has a third side and a fourth side relative to each other along the second direction, the first side and the third side are opposite to each other along the first direction, and the second side and the fourth side are opposite to each other along the first direction; the first direction is a horizontal direction, the first laser emitter is located on a side of the first surface away from the second surface, and the second laser emitter is located on a side of the second surface away from the first surface; and / or, the first laser emitted by the first laser emitter scans from the first side to the second side, and the second laser emitted by the second laser emitter scans from the fourth side to the third side.

[0012] In some embodiments, the steps of using the etching process include: using a first etching process to etch the portion of the initial photovoltaic cell located in the first laser area to at least remove the first laser portion and the second doped film located on the first laser area; using a second etching process to continue etching the portion of the initial photovoltaic cell located in the first laser area to at least remove the first functional film located on the first laser area; using a third etching process to simultaneously etch the first doped film located in the first laser area and the third functional film, the passivation film and the tunneling film located in the second laser area, and further performing texturing on the exposed first laser area and the second laser area so that the first laser area has a first pyramid structure and the second laser area has a second pyramid structure.

[0013] In some embodiments, the steps of using the etching process include: using a fourth etching process to etch the portion of the initial photovoltaic cell located in the first laser area to remove the first laser portion and the second doped film and the first functional film located on the first laser area, and removing the second functional film located in the first non-laser area; using a fifth etching process to simultaneously etch the first doped film located in the first laser area and the third functional film, the passivation film and the tunneling film located in the second laser area, and further texturing the exposed first laser area and the second laser area so that the first laser area has a first pyramid structure and the second laser area has a second pyramid structure.

[0014] According to some embodiments of the present disclosure, on the other hand, the embodiments of the present disclosure further provide a photovoltaic cell, comprising: a crystalline silicon substrate, the crystalline silicon substrate having a first surface and a second surface opposite to each other along a first direction, the first surface comprising a first laser area and a first non-laser area alternately arranged in a second direction, the second surface comprising a second laser area and a second non-laser area alternately arranged in the second direction; an emitter located on the first non-laser area; a tunneling layer located on the second non-laser area; a passivation layer located on a side of the tunneling layer away from the second non-laser area; wherein a first pyramid structure is provided on the first laser area, and a second pyramid structure is provided on the second laser area.

[0015] According to some embodiments of the present disclosure, another aspect of the embodiments of the present disclosure further provides a stacked cell, comprising: a crystalline silicon bottom cell, which is a photovoltaic cell prepared according to any of the preparation methods described above, or the above-mentioned photovoltaic cell; and a perovskite top cell, which is located on a side of the crystalline silicon substrate in the crystalline silicon bottom cell away from the electrode.

[0016] The technical solution provided by the embodiments of the present disclosure has at least the following advantages:

[0017] On the basis of designing different stacked film layers on the first surface and the second surface of the crystalline silicon substrate respectively, a laser processing process is used on the first surface and the second surface at the same time to laser process the different stacked film layers located in the first laser area and the second laser area, so that at least the part of the second functional film located in the first laser area is transformed into the first laser part, and the part of the third functional film located in the second laser area is transformed into the second laser part. In other words, different laser parts are formed on the first surface and the second surface at the same time. Based on this, on the one hand, the same etching process has different etching rates for the first laser portion and the portion of the second functional film located in the first non-laser area, so that without setting an additional mask, the first doped film can be finally selectively etched, that is, only the first doped film located in the first laser area is removed and the remaining first doped film is used as an emitter to form a selective emitter on the first surface; on the other hand, the same etching process has different etching rates for the second laser portion and the portion of the third functional film located in the second non-laser area, so that without setting an additional mask, the passivation film and the tunneling film can be finally selectively etched, that is, only the passivation film and the tunneling film located in the second laser area are removed, and the remaining passivation film is used as a passivation layer and the remaining tunneling film is used as a tunneling layer to form a selective passivation contact structure on the second surface. Therefore, based on the use of laser processing technology on the first surface and the second surface at the same time, it is not only beneficial to simplify the laser processing process in the steps of preparing photovoltaic cells, but also beneficial to make it possible to achieve selective etching of the first doped film, the passivation film and the tunneling film in the subsequent etching process without the need to set up an additional mask, so as to further simplify the etching process in the steps of preparing photovoltaic cells, thereby helping to improve the preparation efficiency of photovoltaic cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] One or more embodiments are exemplarily illustrated by pictures in the corresponding drawings, and these exemplified descriptions do not constitute a limitation on the embodiments. Unless otherwise specified, the pictures in the drawings do not constitute a scale limitation. In order to more clearly illustrate the embodiments of the present disclosure or the technical solutions in the traditional technology, the drawings required for use in the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 A schematic diagram of a first partial cross-sectional structure of an initial photovoltaic cell provided in a preparation method provided in an embodiment of the present disclosure;

[0020] Figure 2 A schematic diagram of a second partial cross-sectional structure of an initial photovoltaic cell provided in a preparation method provided in an embodiment of the present disclosure;

[0021] Figure 3 A schematic diagram of a first partial cross-sectional structure of an initial photovoltaic cell after a laser treatment process in a preparation method provided by an embodiment of the present disclosure;

[0022] Figure 4 A schematic diagram of a second partial cross-sectional structure of an initial photovoltaic cell after a laser treatment process in a preparation method provided by an embodiment of the present disclosure;

[0023] Figure 5 A front view of a first laser emitter, a second laser emitter, and an initial photovoltaic cell in a preparation method provided in an embodiment of the present disclosure;

[0024] Figure 6 A schematic diagram of a first partial cross-sectional structure of an initial photovoltaic cell after undergoing a first etching process in a preparation method provided by an embodiment of the present disclosure;

[0025] Figure 7 A schematic diagram of a second partial cross-sectional structure of an initial photovoltaic cell after undergoing a first etching process in a preparation method provided in an embodiment of the present disclosure;

[0026] Figure 8 A schematic diagram of a first partial cross-sectional structure of an initial photovoltaic cell after undergoing a second etching process in a preparation method provided in an embodiment of the present disclosure;

[0027] Fig. 9 A schematic diagram of a second partial cross-sectional structure of an initial photovoltaic cell after undergoing a second etching process in a preparation method provided by an embodiment of the present disclosure;

[0028] Fig.10 A schematic diagram of a partial cross-sectional structure of an initial photovoltaic cell after undergoing a third etching process or a fifth etching process in a preparation method provided in an embodiment of the present disclosure;

[0029] Fig.11 A schematic diagram of a partial cross-sectional structure of an initial photovoltaic cell after undergoing a fourth etching process in a preparation method provided in an embodiment of the present disclosure;

[0030] Fig.12 A schematic diagram of a partial cross-sectional structure of a first surface of an initial photovoltaic cell after being subjected to a laser treatment process in a preparation method provided in an embodiment of the present disclosure;

[0031] Fig.13 for Fig.12 A schematic diagram of a partial cross-sectional structure of the structure shown after the chain acid positive etching process;

[0032] Fig.14 for Fig.12The structure shown is a schematic diagram of a partial cross-section structure after the chain alkali polishing process;

[0033] Fig.15 A schematic diagram of a partial cross-sectional structure of a stacked battery provided in yet another embodiment of the present disclosure;

[0034] Fig.16 A schematic diagram of a partial three-dimensional structure of a photovoltaic assembly provided in yet another embodiment of the present disclosure;

[0035] Fig.17 for Fig.16 A schematic diagram of a cross-sectional structure along the cross-sectional direction MM1. DETAILED DESCRIPTION

[0036] As can be seen from the background technology, the preparation efficiency of photovoltaic cells needs to be improved.

[0037] The present disclosure provides a photovoltaic cell and a preparation method thereof, and a stacked cell. In the preparation method, on the basis of designing different stacked film layers on the first surface and the second surface of the crystalline silicon substrate, a laser processing process is used on the first surface and the second surface at the same time to form different laser parts on the first surface and the second surface. Based on this, on the one hand, the same etching process makes the etching rate of the first laser part and the part of the second functional film located in the first non-laser area different, so that the first doped film can be finally selectively etched without the need to set up an additional mask, that is, only the first doped film located in the first laser area is removed and the remaining first doped film is used as an emitter; on the other hand, the same etching process makes the etching rate of the second laser part and the part of the third functional film located in the second non-laser area different, so that the passivation film and the tunneling film can be finally selectively etched without the need to set up an additional mask, that is, only the passivation film and the tunneling film located in the second laser area are removed, and the remaining passivation film is used as a passivation layer, and the remaining tunneling film is used as a tunneling layer. Therefore, based on the use of laser processing technology on the first surface and the second surface at the same time, it is not only beneficial to simplify the laser processing process in the steps of preparing photovoltaic cells, but also beneficial to make it possible to achieve selective etching of the first doped film, the passivation film and the tunneling film in the subsequent etching process without the need to set up an additional mask, so as to further simplify the etching process in the steps of preparing photovoltaic cells, thereby helping to improve the preparation efficiency of photovoltaic cells.

[0038] In the description of the embodiments of the present disclosure, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present disclosure, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0039] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present disclosure. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0040] In the description of the embodiments of the present disclosure, the term "and / or" is only a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B may represent: A exists, A and B exist at the same time, and B exists. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0041] In the description of the embodiments of the present disclosure, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0042] In the description of the embodiments of the present disclosure, the orientations or positional relationships indicated by technical terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", and "circumferential" are based on the orientations or positional relationships shown in the accompanying drawings and are only for the convenience of describing the embodiments of the present disclosure and simplifying the description. They 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 embodiments of the present disclosure.

[0043] In the description of the embodiments of the present disclosure, unless otherwise clearly specified and limited, technical terms such as "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, and it can be the internal connection of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present disclosure can be understood according to the specific circumstances.

[0044] In the accompanying drawings corresponding to the embodiments of the present disclosure, the thickness and area of ​​the layers are magnified for better understanding and ease of description. When describing a component (such as a layer, a film, a region or a substrate) on another component or on the surface of another component, the component may be "directly" located on the surface of the other component, or a third component may be present between the two components. On the contrary, when describing a component on the surface of another component or when another component is formed or provided on the surface of a component, it means that there is no third component between the two components. In addition, when describing a component as being "substantially" formed on another component, it means that the component is not formed on the entire surface (or front surface) of the other component, nor is it formed on a partial edge of the entire surface.

[0045] In the description of the embodiments of the present disclosure, when a component "includes" another component, unless otherwise specified, other components are not excluded, and other components may be further included. In addition, when a component such as a layer, a film, a region, or a plate is referred to as being "on / located on" another component, it may be "directly on" the other component (i.e., located on the surface of the other component with no other components between them), or another component may exist in between. In addition, when a component such as a layer, a film, a region, a plate, etc. is "directly located on" another component, or when a component such as a layer, a film, a region, a plate, etc. is located on the surface of another component, it means that no other components are located in between.

[0046] The terms used in the description of the various embodiments described herein are only used to describe specific embodiments and are not intended to be limiting. As used in the description of the various embodiments described and in the appended claims, "the components" are also intended to include plural forms unless the context clearly indicates otherwise. Among them, components include components such as layers, films, regions, or plates.

[0047] The following will describe the various embodiments of the present disclosure in detail with reference to the accompanying drawings. However, it will be appreciated by those skilled in the art that in the various embodiments of the present disclosure, many technical details are provided in order to enable the reader to better understand the embodiments of the present disclosure. However, even without these technical details and various changes and modifications based on the following embodiments, the technical solutions claimed in the embodiments of the present disclosure can be implemented.

[0048] An embodiment of the present disclosure provides a solar cell, which will be described in detail below with reference to the accompanying drawings.

[0049] refer to Figures 1 to 14 , the preparation method of the photovoltaic cell comprises the following steps:

[0050] S101: Reference Figure 1 or Figure 2, an initial photovoltaic cell 10 is provided, the initial photovoltaic cell 10 includes: a crystalline silicon substrate 100, the crystalline silicon substrate 100 has a first surface 110 and a second surface 120 opposite to each other along a first direction X, the first surface 110 includes a first laser area 130 and a first non-laser area 140 alternately arranged along a second direction Y, and the second surface 120 includes a second laser area 150 and a second non-laser area 160 alternately arranged along the second direction Y; a first doping film 101, a first functional film 102, a second doping film 103, and a second functional film 104 covering the first surface 110 and stacked along the first direction X, and a tunneling film 105, a passivation film 106, and a third functional film 107 covering the second surface 120 and stacked in a direction opposite to the first direction X.

[0051] in, Figure 1 A schematic diagram of a first partial cross-sectional structure of an initial photovoltaic cell provided in a preparation method provided in an embodiment of the present disclosure; Figure 2 A schematic diagram of a second partial cross-sectional structure of an initial photovoltaic cell provided in the preparation method provided in one embodiment of the present disclosure.

[0052] In some embodiments, the material of the second doping film 103 and the material of the passivation film 106 can be the same, and the steps of forming the second doping film 103 on the first surface 110 and the step of forming the passivation film 106 on the second surface 120 can be performed simultaneously, thereby further simplifying the steps of preparing the photovoltaic cell. In other embodiments, the second doping film and the passivation film can also be formed in steps.

[0053] In some embodiments, the material of the second functional film 104 and the material of the third functional film 107 can be the same, and the steps of forming the second functional film 104 on the first surface 110 and the steps of forming the third functional film 107 on the second surface 120 can be performed simultaneously, thereby further simplifying the steps of preparing the photovoltaic cell. In other embodiments, the second functional film and the third functional film can also be formed in steps.

[0054] It should be noted that the stacked film layer disposed on the first surface 110 and the stacked film layer disposed on the second surface 120 will be described with examples later, and will not be described in detail here.

[0055] S102: Reference Figures 3 to 5 , a laser processing process is used on the first surface 110 and the second surface 120 at the same time to process the portion of the initial photovoltaic cell 10 located in the first laser area 130 and the portion of the second laser area 150, so that at least the portion of the second functional film 104 located in the first laser area 130 is transformed into the first laser portion 114, and the portion of the third functional film 107 located in the second laser area 150 is transformed into the second laser portion 117.

[0056] It is worth noting that, compared with the initial portion of the second functional film 104 and the portion of the second laser portion 117 that have not been processed by the laser processing process, the portion of the second functional film 104 and the portion of the second laser portion 117 that have been processed by the laser processing process are both modified into loose structures, which are easier to be removed by the subsequent etching process. In other words, compared with the portion of the second functional film 104 located in the first non-laser area 140 and the portion of the third functional film 107 located in the second non-laser area 160, the first laser portion 114 and the second laser portion 117 are loose structures.

[0057] S103: Reference Figures 6 to 14 , using an etching process, the second functional film 104, the second doped film 103, the first functional film 102 and the third functional film 107 are removed, the first doped film 101 located in the first laser region 130 is removed and the remaining first doped film 101 serves as the emitter 111, and the passivation film 106 and the tunneling film 105 located in the second laser region 150 are removed, and the remaining passivation film 106 serves as the passivation layer 126, and the remaining tunneling film 105 serves as the tunneling layer 115.

[0058] In this way, the emitter 111 is only located in the first non-laser area 140, and the emitter 111 forms a selective emitter on the first surface 110, which is beneficial to ensure that the subsequent electrodes have good current collection efficiency based on the emitter 111, while avoiding the first laser area 130 from being covered by the first doped film 101, thereby avoiding the parasitic absorption of the light incident to the first laser area 130 by the first doped film 101, improving the utilization rate of light by the crystalline silicon substrate 100, and improving the photoelectric conversion efficiency of the photovoltaic cell. In addition, the tunneling layer 115 and the passivation layer 126 are only stacked in the second non-laser area 160, and the tunneling layer 115 and the passivation layer 126 form a selective passivation contact structure on the second surface 120, which is beneficial to ensure that the tunneling layer 115 and the passivation layer 126 have a good passivation effect on the second surface 120, while avoiding the second laser area 150 from being covered by the second doped film 103, thereby avoiding the parasitic absorption of the light incident to the second laser area 150 by the second doped film 103, improving the utilization rate of the light by the crystalline silicon substrate 100, and improving the photoelectric conversion efficiency of the photovoltaic cell.

[0059] It is worth emphasizing that, based on the different stacked film layers designed on the first surface 110 and the second surface 120 of the crystalline silicon substrate 100, a laser processing process is used on the first surface 110 and the second surface 120 at the same time to laser process the different stacked film layers located in the first laser area 130 and the second laser area 150, so that at least the part of the second functional film 104 located in the first laser area 130 is transformed into the first laser portion 114, and the part of the third functional film 107 located in the second laser area 150 is transformed into the second laser portion 117. In other words, different laser portions are formed on the first surface 110 and the second surface 120 at the same time. Based on this, on the one hand, the same etching process has different etching rates for the first laser portion 114 and the portion of the second functional film 104 located in the first non-laser area 140, so that the first doped film 101 can be selectively etched without an additional mask, that is, only the first doped film 101 located in the first laser area 130 is removed and the remaining first doped film 101 is used as the emitter 111 to form a selective emitter on the first surface 110; on the other hand, the same etching process has different etching rates for the portion of the second laser portion 117 and the third functional film 107 located in the second non-laser area 160, so that the passivation film 106 and the tunneling film 105 can be selectively etched without an additional mask, that is, only the passivation film 106 and the tunneling film 105 located in the second laser area 150 are removed, and the remaining passivation film 106 is used as the passivation layer 126, and the remaining tunneling film 105 is used as the tunneling layer 115 to form a selective passivation contact structure on the second surface 120. Therefore, based on the simultaneous use of laser processing technology on the first surface 110 and the second surface 120, it is not only beneficial to simplify the laser processing process in the steps of preparing photovoltaic cells, but also beneficial to make it possible to achieve selective etching of the first doping film 101, the passivation film 106 and the tunneling film 105 in the subsequent etching process without the need to set up an additional mask, so as to further simplify the etching process in the steps of preparing photovoltaic cells, thereby helping to improve the preparation efficiency of photovoltaic cells.

[0060] The following will provide a more detailed description of each step in the preparation method provided in one embodiment of the present disclosure in conjunction with the accompanying drawings.

[0061] In some embodiments, the crystalline silicon substrate 100 has a front side and a back side opposite to each other along a first direction X, wherein one of the first surface 110 and the second surface 120 is the front side and the other is the back side. For the convenience of subsequent description, the first surface 110 is the front side and the second surface 120 is the back side.

[0062] In some examples, the photovoltaic cell can be a single-sided cell, the front side of the crystalline silicon substrate can be used as a light-receiving surface for receiving incident light, and the back side can be used as a backlight surface. In other examples, the photovoltaic cell can be a double-sided cell, and both the front side and the back side of the crystalline silicon substrate can be used as light-receiving surfaces, and both can be used to receive incident light. It can be understood that the backlight surface referred to in an embodiment of the present disclosure can also receive incident light, but the degree of receiving the incident light is weaker than the degree of receiving the incident light by the light-receiving surface, and therefore it is defined as a backlight surface.

[0063] In some embodiments, reference Figure 1 or Figure 2 The first surface 110 may include a plurality of first laser regions 130 and a plurality of first non-laser regions 140 , and a first non-laser region 140 is connected between two adjacent first laser regions 130 along the second direction Y.

[0064] In some embodiments, reference Figure 1 or Figure 2 The second surface 120 may include a plurality of second laser regions 150 and a plurality of second non-laser regions 160 , and a second non-laser region 160 is connected between two adjacent second laser regions 150 along the second direction Y.

[0065] In some embodiments, reference Figure 1 or Figure 2 , the orthographic projection area of ​​the first laser zone 130 on the first surface 110 is different from the orthographic projection area of ​​the second laser zone 150 on the first surface 110. It is worth noting that, based on the different types of photovoltaic cells, the different light absorption rates of the first surface 110 and the second surface 120, and the different size designs of the emitter, tunneling layer and passivation layer formed subsequently, the orthographic projection area of ​​the first laser zone 130 on the first surface 110 and the orthographic projection area of ​​the second laser zone 150 on the first surface 110 can be different, that is, the sizes of the first laser zone 130 and the second laser zone 150 are different. In this way, the preparation method provided in an embodiment of the present disclosure is applicable to a variety of photovoltaic cells.

[0066] In one example, the orthographic projection area of ​​the first laser zone on the first surface may be less than or equal to the orthographic projection area of ​​the second laser zone on the first surface; in another example, the orthographic projection area of ​​the first laser zone on the first surface may be greater than the orthographic projection area of ​​the second laser zone on the first surface.

[0067] It should be noted that the orthographic projection areas of the multiple first laser zones 130 on the first surface 110 can be the same or different, and can be designed according to actual needs; the orthographic projection areas of the multiple second laser zones 150 on the first surface 110 can be the same or different, and can also be designed according to actual needs.

[0068] In some embodiments, reference Figure 1 , the orthographic projection of the first laser zone 130 on the first surface 110 does not overlap with the orthographic projection of the second laser zone 150 on the first surface 110. In other words, it is prevented that the first laser zone 130 and the second laser zone 150 are directly opposite to each other along the first direction X. Thus, in step S102: when the laser treatment process is applied to the first surface 110 and the second surface 120 at the same time, it is helpful to prevent the laser acting on the first surface 110 and the laser acting on the second surface 120 from simultaneously treating the same part of the initial photovoltaic cell 10, so as to prevent the initial photovoltaic cell 10 from being locally overheated and damaged, such as fragments.

[0069] In one example, continue to refer to Figure 1 , the first laser area 130 can be opposite to the second non-laser area 160 along the first direction X, that is, the orthographic projection of the first laser area 130 on the first surface 110 coincides with the orthographic projection of the second non-laser area 160 on the first surface 110; the first non-laser area 140 can be opposite to the second laser area 150 along the first direction X, that is, the orthographic projection of the first non-laser area 140 on the first surface 110 coincides with the orthographic projection of the second laser area 150 on the first surface 110.

[0070] In other embodiments, reference Figure 2 The orthographic projection of the first laser zone 130 on the first surface 110 and the orthographic projection of the second laser zone 150 on the first surface 110 may also only partially overlap, which is beneficial to reduce the probability of the initial photovoltaic cell 10 being locally overheated and damaged, such as broken.

[0071] It should be noted that, in practical applications, the orthographic projection area of ​​the first laser zone on the first surface is different from the orthographic projection area of ​​the second laser zone on the first surface, and the orthographic projection of the first laser zone on the first surface does not overlap with the orthographic projection of the second laser zone on the first surface, and they can exist in the same photovoltaic cell at the same time; or, the orthographic projection area of ​​the first laser zone on the first surface is different from the orthographic projection area of ​​the second laser zone on the first surface, and the orthographic projection of the first laser zone on the first surface only partially overlaps with the orthographic projection of the second laser zone on the first surface, and they can exist in the same photovoltaic cell at the same time. For the convenience of explanation, the following Figure 1 The initial photovoltaic cell 10 shown is used as an example to describe step S102 and step S103 .

[0072] In some embodiments, in conjunction with reference Figure 1 and Figure 3 , or in conjunction with reference Figure 1 and Figure 4S102: The step of simultaneously applying a laser processing process to the first surface 110 and the second surface 120 may include: applying a first laser processing process to the first surface 110, and applying a second laser processing process to the second surface 120, and the first laser processing process and the second laser processing process are performed simultaneously; wherein at least one of the laser action time, laser power, laser wavelength, laser spot size or laser scanning speed used in the first laser processing process and the second laser processing process is different.

[0073] in, Figure 3 A schematic diagram of a first partial cross-sectional structure of an initial photovoltaic cell after a laser treatment process in a preparation method provided by an embodiment of the present disclosure; Figure 4 A schematic diagram of a second partial cross-sectional structure of an initial photovoltaic cell after a laser treatment process in a preparation method provided in an embodiment of the present disclosure.

[0074] It is worth noting that factors such as the orthographic projection area of ​​the first laser zone 130 on the first surface 110 is different from the orthographic projection area of ​​the second laser zone 150 on the first surface 110, the orthographic projection of the first laser zone 130 on the first surface 110 and the orthographic projection of the second laser zone 150 on the first surface 110 only partially overlap or do not overlap, and the film layers stacked on the first surface 110 and the second surface 120 are different, can make some process parameters in the first laser processing process and the second laser processing process different, so as to improve the adaptability of the first laser processing process to the first surface 110 and the adaptability of the second laser processing process to the second surface 120, so that when the first laser processing process and the second laser processing process are carried out simultaneously, laser modification of the film layers stacked on the first surface 110 and the second surface 120 can also be achieved respectively.

[0075] In one example, the orthographic projection area of ​​the first laser zone 130 on the first surface 110 is larger than the orthographic projection area of ​​the second laser zone 150 on the first surface 110. Based on this, the area on the first surface 110 that needs to be laser processed is larger than the area on the second surface 120 that needs to be laser processed. The laser spot size used in the first laser processing process can be adjusted to be larger than the laser spot size used in the second laser processing process, so that the laser action area of ​​the first laser processing process is larger than the laser action area of ​​the second laser processing process, so that the first laser processing process matches the first laser zone 130, and the second laser processing process matches the second laser zone 150.

[0076] In another example, the specific situation in which the film layers stacked on the first surface 110 and the second surface 120 are different is: along the first direction X, the thickness of the second functional film 104 is greater than the thickness of the third functional film 107; or, on the first surface 110, in addition to laser processing the second functional film 104, the second doped film 103 also needs to be laser processed, while on the second surface 120 only the third functional film 107 needs to be laser processed, and along the first direction X, the sum of the thickness of the second functional film 104 and the second doped film 103 is greater than the thickness of the third functional film 107.

[0077] Based on this, along the first direction X, the depth of the first surface 110 that needs to be laser processed is greater than the depth of the second surface 120 that needs to be laser processed, then at least one of the laser action time, laser power, and laser spot size used in the first laser processing process can be adjusted to be greater than the corresponding process parameters in the second laser processing process, and the other process parameters can be the same; or, at least one of the laser wavelength and laser scanning speed used in the first laser processing process can be adjusted to be less than the corresponding process parameters in the second laser processing process, and the other process parameters can be the same. In this way, the laser action depth of the first laser processing process is greater than the laser action depth of the second laser processing process, so that the first laser processing process matches the first laser area 130, and the second laser processing process matches the second laser area 150.

[0078] It should be noted that the above are only two examples in which at least one of the laser action time, laser power, laser wavelength, laser spot size or laser scanning speed used in the first laser processing process and the second laser processing process is different. In practical applications, multiple choices can be made according to needs. The first laser processing process and the second laser processing process are described in detail below by way of example.

[0079] In some embodiments, in conjunction with reference Figure 1 and Figure 3 , or in conjunction with reference Figure 1 and Figure 4The step of using a first laser processing process on the first surface 110 may include: using a first laser action time, a first laser power, a first laser wavelength, a first laser spot size and a first laser scanning speed to process a portion of the initial photovoltaic cell 10 located in the first laser area 130; the step of using a second laser processing process on the second surface 120 may include: using a second laser action time, a second laser power, a second laser wavelength, a second laser spot size and a second laser scanning speed to process a portion of the initial photovoltaic cell 10 located in the second laser area 150; wherein the first laser action time is greater than the second laser action time; and / or the first laser power is greater than the second laser power; and / or the first laser spot size is greater than the second laser spot size; and the first laser wavelength is less than the second laser wavelength.

[0080] In this way, based on the adjustment of the process parameters of the first laser processing process and the second laser processing process, the second functional film 104 located in the entire thickness of the first laser zone 130 is at least transformed into the first laser portion 114 as much as possible, and the third functional film 107 located in the entire thickness of the second laser zone 150 is transformed into the second laser portion 117.

[0081] It is worth noting that the greater the laser action time, the greater the laser power or the laser spot size, the deeper the laser action depth, that is, the deeper the depth of the film layer into the laser portion; the shorter the laser wavelength, the greater the laser energy, and the deeper the laser action depth. Based on this, the first laser action time is designed to be greater than the second laser action time; and / or the first laser power is greater than the second laser power; and / or the first laser spot size is greater than the second laser spot size; the first laser wavelength is smaller than the second laser wavelength, which is conducive to making the laser act on the first surface 110. The first doped film 101, the first functional film 102, the second doped film 103 and the second functional film 104 constitute a deeper depth of the stacked structure, not only the second functional film 104 located in the entire thickness of the first laser area 130 is transformed into the first laser portion 114, but also the second doped film 103 located in at least part of the thickness of the first laser area 130 is also transformed into the laser portion, that is, a loose structure, which is conducive to the subsequent removal of the second doped film 103 by etching process.

[0082] It should be noted that, in some cases, the four situations of the first laser action duration being greater than the second laser action duration, the first laser power being greater than the second laser power, the first laser spot size being greater than the second laser spot size, and the first laser wavelength being smaller than the second laser wavelength may exist at the same time, and all four parameters are fine-tuned in step S102.

[0083] In other cases, at least one of the four situations that the first laser action time is greater than the second laser action time, the first laser power is greater than the second laser power, the first laser spot size is greater than the second laser spot size, and the first laser wavelength is less than the second laser wavelength may exist, and at least one of the four process parameters has the same value in the first laser processing process and the second laser processing process. For example, the first laser action time is greater than the second laser action time, the first laser power is greater than the second laser power, but the first laser spot size is equal to the second laser spot size, and the first laser wavelength is equal to the second laser wavelength.

[0084] It is worth noting that the first laser action time and the first laser scanning speed affect each other, and the longer the first laser action time, the slower the first laser scanning speed. Similarly, the second laser action time and the second laser scanning speed affect each other, and the longer the second laser action time, the slower the second laser scanning speed.

[0085] In one example, the first laser power used in the first laser processing process is 25 watts to 30 watts, and the first laser scanning speed is 2.5 mm / s to 3 mm / s; the second laser power used in the second laser processing process is 15 watts to 20 watts, and the second laser scanning speed is 3 mm / s to 4 mm / s; the first laser spot size used in the first laser processing process is equal to the second laser spot size used in the second laser processing process, and the first laser wavelength used in the first laser processing process is equal to the second laser wavelength used in the second laser processing process.

[0086] The influence of the first laser treatment process on the stacked film layer located on the first surface 110 is described in detail below.

[0087] In some cases, reference Figure 3 , Figure 3 This is a schematic diagram of the first local cross-sectional structure of an initial photovoltaic cell after a laser treatment process in a preparation method provided in an embodiment of the present disclosure. In the step of applying the first laser treatment process to the first surface 110, only the portion of the second functional film 104 located in the first laser zone 130 is transformed into the first laser portion 114.

[0088] In other cases, reference Figure 4 , Figure 4 This is a schematic diagram of a second local cross-sectional structure of an initial photovoltaic cell after a laser treatment process in a preparation method provided in an embodiment of the present disclosure. In the step of applying the first laser treatment process to the first surface 110, not only the portion of the second functional film 104 located in the first laser region 130 is transformed into the first laser portion 114, but also the portion of the second doped film 103 located in the first laser region 130 is transformed into the third laser portion 113.

[0089] It should be noted that the two situations in which the stacked film layer located in the first laser zone 130 is converted into the laser part can be achieved by adjusting at least one of the laser action time, laser power, laser wavelength, laser spot size or laser scanning speed used in the first laser processing process.

[0090] The influence of the second laser treatment process on the stacked film layer located on the second surface 120 is described in detail below.

[0091] In some cases, continue to refer to Figure 3 In the step of applying the second laser treatment process to the second surface 120 , only the portion of the third functional film 107 located in the second laser region 150 is transformed into the second laser portion 117 .

[0092] In other cases, continue to refer to Figure 4 In the step of applying the second laser treatment process to the second surface 120 , not only the portion of the third functional film 107 located in the second laser region 150 is transformed into the second laser portion 117 , but also the portion of the passivation film 106 located in the second laser region 150 is transformed into the fourth laser portion 116 .

[0093] It should be noted that the two situations in which the stacked film layer located in the second laser zone 150 is converted into a laser part can be achieved by adjusting at least one of the laser action time, laser power, laser wavelength, laser spot size or laser scanning speed used in the second laser processing process.

[0094] In addition, the two situations where the stacked film layer in the first laser zone 130 is transformed into the laser part and the two situations where the stacked film layer in the second laser zone 150 is transformed into the laser part can be arbitrarily combined in pairs to form four different steps S102. Figure 3 In the example, only the portion of the second functional film 104 located in the first laser region 130 is transformed into the first laser portion 114, and only the portion of the third functional film 107 located in the second laser region 150 is transformed into the second laser portion 117. In one example, the laser action time of the first laser treatment process and the second laser treatment process is 0.5s to 5s. Figure 4 In the example, a portion of the second functional film 104 located in the first laser area 130 is transformed into the first laser portion 114, a portion of the second doping film 103 located in the first laser area 130 is transformed into the third laser portion 113, a portion of the third functional film 107 located in the second laser area 150 is transformed into the second laser portion 117, and a portion of the passivation film 106 located in the second laser area 150 is transformed into the fourth laser portion 116. In one example, the laser action time of the first laser processing process and the second laser processing process is 2s to 4s.

[0095] In practical applications, after executing step S102, the first laser portion and the third laser portion can be formed on the first surface, and only the second laser portion can be formed on the second surface; alternatively, only the first laser portion can be formed on the first surface, and the second laser portion and the fourth laser portion can be formed on the second surface.

[0096] In one example, the laser used in the laser processing process in step S102 may be purple laser, green laser or red laser with a frequency of 1000kHz to 2000kHz.

[0097] In some embodiments, in conjunction with reference Figure 1 and Figure 5 , Figure 5 A front view of the first laser emitter, the second laser emitter and the initial photovoltaic cell in the preparation method provided in one embodiment of the present disclosure, in the step of adopting the stacked first laser processing process on the first surface 110: the first laser emitter 119 is adopted to emit the first laser; in the step of adopting the second laser processing process on the second surface 120: the second laser emitter 129 is adopted to emit the second laser; the first surface 110 has a relative first side 110a and a second side 110b along the second direction Y, and the second surface 120 has a relative third side 120a and a fourth side 120b along the second direction Y, the first side 110a and the third side 120a are opposite to each other along the first direction X, and the second side 110b and the fourth side 120b are opposite to each other along the first direction X.

[0098] The relative positional relationship between the first laser emitter 119 and the second laser emitter 129 and the initial photovoltaic cell 10 is described in detail below.

[0099] In some cases, in conjunction with reference Figure 1 and Figure 5 The first direction X is a horizontal direction. The first laser emitter 119 is located on a side of the first surface 110 away from the second surface 120 . The second laser emitter 129 is located on a side of the second surface 120 away from the first surface 110 .

[0100] In other words, unlike the conventional horizontally laid out arrangement of the solar cells, the initial photovoltaic cell 10 is placed vertically, with the first surface 110 and the second surface 120 respectively located on the left and right sides of the initial photovoltaic cell 10, and the first laser emitter 119 and the second laser emitter 129 are also adaptively arranged on the left and right sides of the initial photovoltaic cell 10. The relative position relationship between the first laser emitter 119 and the second laser emitter 129 and the initial photovoltaic cell 10 is arranged in this way, so that the first laser emitter 119 and the second laser emitter 129 can perform laser processing on the first surface 110 and the second surface 120 respectively at the same time, so as to ensure that the laser processing processes on the first surface 110 and the second surface 120 are carried out simultaneously.

[0101] In other cases, continue to combine reference Figure 1 and Figure 5 , the first laser emitted by the first laser emitter 119 scans from the first side 110a to the second side 110b, and the second laser emitted by the second laser emitter 129 scans from the fourth side 120b to the third side 120a. In other words, setting the moving starting point of the first laser emitted by the first laser emitter 119 as the moving end point of the second laser emitted by the second laser emitter 129, and setting the moving end point of the first laser emitted by the first laser emitter 119 as the moving starting point of the second laser emitted by the second laser emitter 129, is conducive to significantly reducing the probability that the first laser emitted by the first laser emitter 119 and the second laser emitted by the second laser emitter 129 simultaneously irradiate the same area of ​​the initial photovoltaic cell 10 during the process of step S102, thereby effectively reducing the probability that the initial photovoltaic cell 10 is locally overheated and damaged, such as fragmented.

[0102] It should be noted that Figure 5 In the example, the first side 110a, the second side 110b, the third side 120a and the fourth side 120b are all parallel to the horizontal plane, the first laser emitted by the first laser emitter 119 scans the first surface 110 from top to bottom, and the second laser emitted by the second laser emitter 129 scans the second surface 120 from bottom to top. In practical applications, the first side, the second side, the third side and the fourth side may all be perpendicular to the horizontal plane, the first laser emitted by the first laser emitter scans the first surface from front to back, and the second laser emitted by the second laser emitter scans the second surface from back to front.

[0103] In other words, it is only necessary to set the scanning direction of the first laser emitted by the first laser emitter to be opposite to the scanning direction of the second laser emitted by the second laser emitter. This will help to significantly reduce the probability of the first laser emitted by the first laser emitter 119 and the second laser emitted by the second laser emitter 129 simultaneously irradiating the same area of ​​the initial photovoltaic cell 10 during the step S102.

[0104] It should be noted that the first laser emitter 119 and the second laser emitter 129 are adaptively arranged on the left and right sides of the initial photovoltaic cell 10, and the first laser emitted by the first laser emitter and the second laser emitted by the second laser emitter have opposite scanning directions and can exist simultaneously in the same step S102.

[0105] In some embodiments, the crystalline silicon substrate 100 may be an N-type semiconductor substrate or a P-type semiconductor substrate. The N-type semiconductor substrate is doped with an N-type doping element, and the N-type doping element may be any one of the V-group elements such as phosphorus (P), bismuth (Bi), antimony (Sb), or arsenic (As). The P-type semiconductor substrate is doped with a P-type element, and the P-type doping element may be any one of the III-group elements such as boron (B), aluminum (Al), gallium (Ga), or gallium (In).

[0106] In some examples, the material of the first doped film 101 may be a silicon material doped with a P-type doping element, for example, the first doped film 101 may be a boron diffusion layer; the material of the first functional film 102 may be a semiconductor material doped with a P-type doping element, for example, the first functional film 102 may be a borosilicate glass layer; the material of the second doped film 103 may be a silicon material doped with an N-type doping element, for example, the second doped film 103 may be a polycrystalline silicon layer doped with a phosphorus element; the material of the second functional film 104 may be a semiconductor material doped with an N-type doping element, for example, the second functional film 104 may be a phosphosilicate glass layer doped with a phosphorus element; the tunneling film 105 may be a silicon oxide layer; the material of the passivation film 106 may be a silicon material doped with an N-type doping element, for example, the passivation film 106 may be a polycrystalline silicon layer doped with a phosphorus element; the material of the third functional film 107 may be a semiconductor material doped with an N-type doping element, for example, the third functional film 107 may be a phosphosilicate glass layer doped with a phosphorus element.

[0107] It should be noted that the present disclosure does not limit the preparation processes of the first doping film 101, the first functional film 102, the second doping film 103, the second functional film 104, the tunneling film 105, the passivation film 106 and the third functional film 107.

[0108] In the following, taking the first doped film 101 as a boron diffusion layer, the first functional film 102 as a borosilicate glass layer, the tunneling film 105 as a silicon oxide layer, the second doped film 103 and the passivation film 106 as polysilicon layers doped with phosphorus, and the second functional film 104 and the third functional film 107 as phosphosilicate glass layers doped with phosphorus as an example, step S103 in the preparation method provided in an embodiment of the present disclosure is described in detail.

[0109] In some embodiments, the etching process may include the following steps:

[0110] refer to Figure 6 or Figure 7 The first etching process is used to etch the portion of the initial photovoltaic cell 10 located in the first laser region 130 to at least remove the first laser portion 114 and the second doping film 103 located on the first laser region 130 .

[0111] In some cases, in conjunction with reference Figure 3 and Figure 6 , Figure 6 A schematic diagram of a first local cross-sectional structure of an initial photovoltaic cell after a first etching process in a preparation method provided in an embodiment of the present disclosure is provided. In the step of adopting the first etching process, no additional mask is required. The second functional film 104 located on the first non-laser area 140 is used as an etching barrier layer to remove the first laser portion 114 and the second doped film 103 located on the first laser area 130, thereby exposing the first functional film 102 located on the first laser area 130.

[0112] In some examples, the first etching process may be a chain alkali polishing process. In one example, the etching solution used in the chain alkali polishing process may be a sodium hydroxide solution, the concentration of sodium hydroxide in the etching solution is 2% to 10%, and the cleaning time of the chain alkali polishing process is 50s to 80s.

[0113] It is worth noting that the etching rate of the chain alkali polishing process for the first laser portion 114 is much greater than the etching rate for the second functional film 104 located in the first non-laser area 140. Therefore, the second functional film 104 located on the first non-laser area 140 can be used as an etching barrier layer to remove the first laser portion 114 and the second doped film 103 located on the first laser area 130.

[0114] In other cases, combined with reference Figure 3 and Figure 7 , Figure 7 The present invention is a schematic diagram of a second partial cross-sectional structure of an initial photovoltaic cell after a first etching process in a preparation method provided in an embodiment of the present invention. In the step of adopting the first etching process, no additional mask is required, and the second functional film 104 and the second doped film 103 located on the first non-laser area 140 are used together as an etching barrier layer. In addition to removing the first laser portion 114 and the second doped film 103 located on the first laser area 130, the second functional film 104 located in the first non-laser area 140 is also removed, and a partial thickness of the second doped film 103 located on the first non-laser area 140 is removed, exposing the first functional film 102 located on the first laser area 130 and the remaining second doped film 103 located in the first non-laser area 140.

[0115] In some examples, the first etching process may be a chain acid positive etching process. In one example, the etching solution used in the chain acid positive etching process may be a mixed solution of nitric acid and hydrofluoric acid, the concentration of nitric acid in the etching solution is 0.5% to 10%, the concentration of hydrofluoric acid in the etching solution is 30% to 60%, and the cleaning time of the chain acid positive etching process is 40s to 70s.

[0116] It is worth noting that the etching rate of the first laser part 114 by the chain acid positive etching process is also greater than the etching rate of the second functional film 104 located in the first non-laser area 140, but the difference in the etching rates of the first laser part 114 and the second functional film 104 is limited. When the first laser part 114 is about to be completely removed, the chain acid positive etching process has also etched away a portion of the thickness of the second functional film 104 located in the first non-laser area 140. Further, when removing the second doped film 103 located on the first laser area 130, the chain acid positive etching process will further etch away the remaining second functional film 104 located in the first non-laser area 140, and may further etch away a portion of the thickness of the second doped film 103 located in the first non-laser area 140. Therefore, the second functional film 104 and the second doped film 103 located in the first non-laser area 140 can be used together as an etching stop layer to remove the first laser part 114 and the second doped film 103 located in the first laser area 130.

[0117] In other words, in the step of adopting the first etching process: a chain acid positive etching process can be adopted to remove the second functional film 104 having the first laser portion 114 and the second doped film 103 located on the first laser region 130, and to remove a portion of the second doped film 103 located on the first non-laser region 140. It is worth noting that, with the help of the first laser portion 114, the difference in etching rate of the chain acid positive etching process on the first laser portion 114 and the second functional film 104 located on the first non-laser region 140 can be adjusted, so as to finally remove the first laser portion 114 and the second doped film 103 located on the first laser region 130.

[0118] It is worth noting that in the above two situations, no matter what kind of etching solution is used in the first etching process, no additional mask is required to remove the first laser part 114 and the second doped film 103 located on the first laser area 130, and the first non-laser area 140 also has the second doped film 103.

[0119] refer to Figures 6 to 9 The second etching process is used to continue etching the portion of the initial photovoltaic cell 10 located in the first laser region 130 to at least remove the first functional film 102 located on the first laser region 130 .

[0120] In some cases, reference Figure 6 After the first etching process, the first functional film 102 located on the first laser region 130 is exposed, and the second functional film 104 and the second doping film 103 located on the first non-laser region 140 are not removed. Figure 6 and Figure 8 , Figure 8A schematic diagram of a first partial cross-sectional structure of an initial photovoltaic cell after a second etching process in a preparation method provided in an embodiment of the present disclosure is provided. In the step of adopting the second etching process, no additional mask is required. The second doped film 103 located on the first non-laser area 140 is used as an etching barrier layer to remove the first functional film 102 located on the first laser area 130, and the second functional film 104 located on the first non-laser area 140 is also removed, thereby exposing the first doped film 101 located on the first laser area 130 and the second doped film 103 located on the first non-laser area 140.

[0121] In some examples, the second etching process may be a chain hydrofluoric acid process. In one example, the etching solution used in the chain hydrofluoric acid process may be a hydrofluoric acid solution, the concentration of hydrofluoric acid in the etching solution is 30% to 70%, and the cleaning time of the chain hydrofluoric acid process is 30s to 60s, for example, 40s to 50s.

[0122] It is worth noting that the etching rate of the second functional film 104 and the etching rate of the first functional film 102 by the chain hydrofluoric acid process are both relatively large, and the etching rate of the second doped film 103 by the chain hydrofluoric acid process is almost 0, that is, the etching rates of the second functional film 104 and the first functional film 102 by the chain hydrofluoric acid process are both much greater than the etching rate of the second doped film 103, so the second doped film 103 located on the first non-laser area 140 can be used as an etching barrier layer to remove the first functional film 102 located on the first laser area 130 and the second functional film 104 located on the first non-laser area 140.

[0123] In other cases, combined with reference Figure 3 and Figure 7 After the first etching process, the first functional film 102 located on the first laser region 130 is exposed, and the second functional film 104 located on the first non-laser region 140 has been removed, that is, the second doped film 103 located on the first non-laser region 140 has been exposed. Based on this, combined with reference Figure 7 and Fig. 9 , Fig. 9 A schematic diagram of a second local cross-sectional structure of an initial photovoltaic cell after a second etching process in a preparation method provided in an embodiment of the present disclosure is provided. In the step of adopting the second etching process, no additional mask is required. The second doped film 103 located on the first non-laser area 140 is used as an etching barrier layer to remove the first functional film 102 located on the first laser area 130, thereby exposing the first doped film 101 located on the first laser area 130.

[0124] In some examples, the second etching process may be a chain hydrofluoric acid process. In one example, the etching solution used in the chain hydrofluoric acid process may be a hydrofluoric acid solution, the concentration of hydrofluoric acid in the etching solution is 30% to 70%, and the cleaning time of the chain hydrofluoric acid process is 30s to 60s, for example, 40s to 50s.

[0125] It is worth noting that the etching rate of the first functional film 102 by the chain hydrofluoric acid process is much greater than the etching rate of the second doped film 103. The etching rate of the second doped film 103 by the chain hydrofluoric acid process is almost 0. Therefore, the second doped film 103 located on the first non-laser area 140 can be used as an etching barrier layer to remove the first functional film 102 located on the first laser area 130.

[0126] refer to Figures 8 to 10 , using a third etching process, the first doped film 101 located in the first laser area 130 and the third functional film 107, the passivation film 106 and the tunneling film 105 located in the second laser area 150 are etched at the same time, and the exposed first laser area 130 and the second laser area 150 are further textured, so that the first laser area 130 has a first pyramid structure 130a, and the second laser area 150 has a second pyramid structure 150a.

[0127] In some cases, reference Figure 8 or Fig. 9 After the second etching process, the first doped film 101 on the first laser region 130 is exposed, and at least a portion of the second doped film 103 on the first non-laser region 140 and the first functional film 102 on the first non-laser region 140 are not removed.

[0128] Based on this, combined with reference Figure 8 and Fig.10 , or in conjunction with reference Fig. 9 and Fig.10 , Fig.10A schematic diagram of a partial cross-sectional structure of an initial photovoltaic cell after a third etching process in a preparation method provided in an embodiment of the present disclosure, wherein in the step of adopting the third etching process, for the first surface 110, no additional mask is required, and the second doped film 103 and the first functional film 102 located on the first non-laser area 140 are used as etching barrier layers, and the first doped film 101 located on the first laser area 130 is removed, and the second doped film 103 and the first functional film 102 located on the first non-laser area 140 are further removed, and the exposed first laser area 130 is textured, and the first doped film 101 located on the first non-laser area 140 is retained as an emitter 111, and a first pyramid structure 130a is formed on the first laser area 130; For the second surface 120, the third functional film 107 located on the second non-laser area 160 is first used as an etching barrier layer to remove the second laser portion 117 located on the second laser area 150, and further the passivation film 106 and the tunneling film 105 located on the second laser area 150 are removed, and the exposed second laser area 150 is textured so that the second laser area 150 has a second pyramid structure 150a, and then the passivation film 106 located on the second non-laser area 160 is used as an etching barrier layer to remove the third functional film 107 located on the second non-laser area 160, and the passivation film 106 located on the second non-laser area 160 is retained as the passivation layer 126, and the tunneling film 105 located on the second non-laser area 160 is retained as the tunneling layer 115.

[0129] In some examples, the third etching process may include a texturing step and a pickling step. In one example, the etching solution used in the texturing step may be a sodium hydroxide solution, the concentration of sodium hydroxide in the etching solution is 1% to 6%, the texturing time of the texturing step is 500s to 950s, and the process temperature of the texturing step is 70°C to 95°C; the etching solution used in the pickling step may be a hydrofluoric acid solution, and the concentration of hydrofluoric acid in the etching solution is 5% to 15%.

[0130] It is worth noting that, for the second surface 120, the etching rate of the third functional film 107 located on the second non-laser area 160 in the texturing step is much lower than the etching rate of the second laser portion 117. The etching rate of the third functional film 107 located on the second non-laser area 160 in the texturing step is almost 0. Therefore, the third functional film 107 located on the second non-laser area 160 can be used as an etching barrier layer, the second laser portion 117 located on the second laser area 150 is removed, and the passivation film 106 and the tunneling film 105 located on the second laser area 150 are further removed, and the exposed second laser area 150 is texturized, so that the second laser area 150 has There is a second pyramid structure 150a; the etching rate of the third functional film 107 located on the second non-laser area 160 in the pickling step is much higher than the etching rate of the passivation film 106 located on the second non-laser area 160, and the etching rate of the passivation film 106 located on the second non-laser area 160 in the pickling step is almost 0, so the passivation film 106 located on the second non-laser area 160 can be used as an etching barrier layer, the third functional film 107 located on the second non-laser area 160 is removed, and the passivation film 106 located on the second non-laser area 160 is retained as a passivation layer 126, and the tunneling film 105 located on the second non-laser area 160 is retained as a tunneling layer 115.

[0131] In some other embodiments, the etching process may include the following steps:

[0132] Combined with reference Figure 4 and Fig.11 The fourth etching process is used to etch the portion of the initial photovoltaic cell 10 located in the first laser area 130 to remove the first laser portion 114 and the second doping film 103 and the first functional film 102 located on the first laser area 130, and to remove the second functional film 104 located in the first non-laser area 140.

[0133] In some cases, in conjunction with reference Figure 4 and Fig.11 , Fig.11A schematic diagram of a local cross-sectional structure of an initial photovoltaic cell after undergoing a fourth etching process in a preparation method provided in an embodiment of the present disclosure, in the step of adopting the first laser treatment process on the first surface 110, not only the portion of the second functional film 104 located in the first laser area 130 is transformed into the first laser portion 114, but also the portion of the second doped film 103 located in the first laser area 130 is transformed into the third laser portion 113, so that the etching rate of the third laser portion 113 by the fourth etching process is much greater than that of the second doped film 103 located on the first laser area 130, and the etching rate of the second doped film 103 located on the first laser area 130 by the fourth etching process is almost 0, but the etching rates of the first laser portion 114 and the second functional film 104 located on the first non-laser area 140 by the fourth etching process are almost the same. Based on this, in the step of adopting the fourth etching process, there is no need to set an additional mask, and the second doped film 103 located on the first non-laser area 140 can be used as an etching barrier to remove the first laser part 114 and the third laser part 113, and to remove the second functional film 104 located on the first non-laser area 140. Furthermore, the second doped film 103 located on the first non-laser area 140 can be used as an etching barrier to remove the first functional film 102 located on the first laser area 130. In other words, whether the second functional film 104 is laser-treated or not, it can be etched by the fourth etching process. Unlike the second doped film 103, the second doped film 103 that has not been laser-treated, that is, the second doped film 103 located on the first non-laser area 140, can be used as an etching barrier in the fourth etching process.

[0134] In some examples, the fourth etching process may be a chain hydrofluoric acid process. In one example, the etching solution used in the chain hydrofluoric acid process may be a hydrofluoric acid solution, the concentration of hydrofluoric acid in the etching solution is 30% to 70%, and the cleaning time of the chain hydrofluoric acid process is 60s to 90s.

[0135] It is worth noting that, regardless of whether the second functional film 104 and the first functional film 102 are treated by laser, the etching rate of the second functional film 104 and the etching rate of the first functional film 102 by the chain hydrofluoric acid process are both relatively large, and the etching rate of the second doped film 103 that has not been treated by laser by the chain hydrofluoric acid process is almost 0, that is, the etching rates of the second functional film 104 and the first functional film 102 by the chain hydrofluoric acid process are both much greater than the etching rate of the second doped film 103 located on the first non-laser area 140, and thus the second doped film 103 located on the first non-laser area 140 can be used as an etching stop layer to remove the second functional film 104, the third laser portion 113 and the first functional film 102 located in the first laser area 130 to expose the first doped film 101 located on the first laser area 130.

[0136] Combined with reference Fig.11 and Fig.10 , using the fifth etching process, the first doped film 101 located in the first laser area 130 and the third functional film 107, the passivation film 106 and the tunneling film 105 located in the second laser area 150 are etched at the same time, and the exposed first laser area 130 and the second laser area 150 are further textured, so that the first laser area 130 has a first pyramid structure 130a, and the second laser area 150 has a second pyramid structure 150a.

[0137] It is worth noting that in the step of adopting the fifth etching process, the second doping film 103 and the first functional film 102 located on the first non-laser region 140 are also removed.

[0138] Based on this, in the step of adopting the fifth etching process, for the first surface 110, there is no need to set an additional mask, and the second doped film 103 and the first functional film 102 located on the first non-laser area 140 are used as etching barrier layers, and the first doped film 101 located on the first laser area 130 is removed, and the second doped film 103 and the first functional film 102 located on the first non-laser area 140 are further removed, and the exposed first laser area 130 is textured, and the first doped film 101 located on the first non-laser area 140 is retained as the emitter 111, and a first pyramid structure 130a is formed on the first laser area 130; for the second surface 120, first, the second doped film 103 and the first functional film 102 located on the first non-laser area 140 are used as etching barrier layers. The third functional film 107 on the optical area 160 is an etching barrier layer, and the second laser portion 117 located on the second laser area 150 is removed. The passivation film 106 and the tunneling film 105 located on the second laser area 150 are further removed, and the exposed second laser area 150 is textured so that the second laser area 150 has a second pyramid structure 150a, and then the passivation film 106 located on the second non-laser area 160 is used as an etching barrier layer to remove the third functional film 107 located on the second non-laser area 160, and the passivation film 106 located on the second non-laser area 160 is retained as a passivation layer 126, and the tunneling film 105 located on the second non-laser area 160 is retained as a tunneling layer 115.

[0139] In some examples, the fifth etching process may include a texturing step and a pickling step. In one example, the etching solution used in the texturing step may be a sodium hydroxide solution, the concentration of sodium hydroxide in the etching solution is 1% to 6%, the texturing time of the texturing step is 500s to 950s, and the process temperature of the texturing step is 70°C to 95°C; the etching solution used in the pickling step may be a hydrofluoric acid solution, and the concentration of hydrofluoric acid in the etching solution is 5% to 15%.

[0140] It should be noted that the parts of the fifth etching process that are the same as or similar to the aforementioned third etching process are not repeated here.

[0141] In some other embodiments, reference Fig.12 , firstly, a laser treatment process is applied to the first surface 110 so that the portion of the second functional film 104 located in the first laser region 130 is transformed into the first laser portion 114; Figure 7 , and then a laser treatment process is applied to the second surface 120, so that the portion of the third functional film 107 located in the second laser region 150 is transformed into the second laser portion 117. It should be noted that the parameters of the laser treatment process are the same as or corresponding to those in the above embodiment, and are not repeated here.

[0142] Based on this, in some cases, the etching process may include the following steps:

[0143] Combined with reference Fig.12 and Fig.13 After forming the first laser portion 114 and before forming the second laser portion, a chain acid positive etching process is used without additionally setting a mask, and the second functional film 104 and the second doped film 103 located on the first non-laser area 140 are used together as an etching stop layer to remove the first laser portion 114 and the second doped film 103 located on the first laser area 130. Moreover, in the stage of removing the second doped film 103 located on the first laser area 130, the chain acid positive etching process will further etch away the remaining second functional film 104 located in the first non-laser area 140, and may further etch away a portion of the thickness of the second doped film 103 located in the first non-laser area 140. It should be noted that the parameters of the chain acid positive etching process are the same as or corresponding to those in the aforementioned embodiment, and are not repeated here.

[0144] in, Fig.12 A schematic diagram of a partial cross-sectional structure of a first surface of an initial photovoltaic cell after a laser treatment process in a preparation method provided in an embodiment of the present disclosure, Fig.13 for Fig.12 The structure shown is a schematic diagram of a partial cross-section structure after the chain acid etching process.

[0145] Further, combined with reference Figure 7 and Fig. 9 After forming the second laser portion 117, a chain hydrofluoric acid process is used without setting an additional mask, and the remaining second doping film 103 located on the first non-laser area 140 is used as an etching barrier to remove the first functional film 102 located on the first laser area 130, thereby exposing the first doping film 101 located on the first laser area 130. It should be noted that the parameters of the chain hydrofluoric acid process are the same as or corresponding to those in the above-mentioned embodiment, and are not described in detail here.

[0146] In other cases, the etching process may include the following steps:

[0147] Combined with reference Fig.12 and Fig.14 After forming the first laser portion 114 and before forming the second laser portion, a chain alkali polishing process is used to remove the first laser portion 114 and the second doping film 103 located on the first laser region 130 by using the second functional film 104 located on the first non-laser region 140 as an etching barrier. It should be noted that the parameters of the chain alkali polishing process are the same as or corresponding to those in the above-mentioned embodiment, and are not described in detail here.

[0148] Further, combined with reference Figure 6 and Figure 8 After forming the second laser portion 117, a chain hydrofluoric acid process is used without additionally setting a mask, and the second doping film 103 located on the first non-laser area 140 is used as an etching barrier layer to remove the first functional film 102 located on the first laser area 130, and also remove the second functional film 104 located on the first non-laser area 140, thereby exposing the first doping film 101 located on the first laser area 130 and the second doping film 103 located on the first non-laser area 140. It should be noted that the parameters of the chain hydrofluoric acid process are the same as or corresponding to those in the above-mentioned embodiment, and are not described in detail here.

[0149] In the above two cases, combined with reference Figure 8 and Fig.10 , or in combination with reference Fig. 9 and Fig.10 After the first doped film 101 located on the first laser region 130 is exposed, a texturing step and an acid washing step are sequentially used to simultaneously etch the first doped film 101 located in the first laser region 130 and the third functional film 107, the passivation film 106 and the tunneling film 105 located in the second laser region 150, and further texturing is performed on the exposed first laser region 130 and the second laser region 150, so that the first laser region 130 has a first pyramid structure 130a, and the second laser region 150 has a second pyramid structure 150a. It should be noted that the parameters of the texturing step and the acid washing step are the same as or corresponding to those in the aforementioned embodiment, and are not repeated here.

[0150] In summary, the laser processing process is used on the first surface 110 and the second surface 120 at the same time, and different laser parts are formed on the first surface 110 and the second surface 120 at the same time. Based on this, on the one hand, the same etching process makes the etching rates of the first laser part 114 and the part of the second functional film 104 located in the first non-laser area 140 different, so that without setting an additional mask, only the first doped film 101 located in the first laser area 130 can be removed and the remaining first doped film 101 can be used as the emitter 111 to form a selective emitter on the first surface 110; on the other hand, the same etching process makes the etching rates of the second laser part 117 and the part of the third functional film 107 located in the second non-laser area 160 different, so that without setting an additional mask, only the passivation film 106 and the tunneling film 105 located in the second laser area 150 can be removed, and the remaining passivation film 106 can be used as the passivation layer 126, and the remaining tunneling film 105 can be used as the tunneling layer 115 to form a selective passivation contact structure on the second surface 120. Therefore, based on the simultaneous use of laser processing technology on the first surface 110 and the second surface 120, it is not only beneficial to simplify the laser processing process in the steps of preparing photovoltaic cells, but also beneficial to make it possible to achieve selective etching of the first doping film 101, the passivation film 106 and the tunneling film 105 in the subsequent etching process without the need to set up an additional mask, so as to further simplify the etching process in the steps of preparing photovoltaic cells, thereby helping to improve the preparation efficiency of photovoltaic cells.

[0151] Another embodiment of the present disclosure also provides a photovoltaic cell, which is formed by the preparation method provided in the above embodiment. The photovoltaic cell provided in another embodiment of the present disclosure will be described in detail below in conjunction with the accompanying drawings. It should be noted that the parts that are the same or corresponding to the above embodiment will not be repeated here.

[0152] refer to Fig.10 The photovoltaic cell includes: a crystalline silicon substrate 100, the crystalline silicon substrate 100 has a first surface 110 and a second surface 120 opposite to each other along a first direction X, the first surface 110 includes a first laser area 130 and a first non-laser area 140 alternately arranged in a second direction Y, and the second surface 120 includes a second laser area 150 and a second non-laser area 160 alternately arranged in the second direction Y; an emitter 111, located on the first non-laser area 140; a tunneling layer 115, located on the second non-laser area 160; a passivation layer 126, located on a side of the tunneling layer 115 away from the second non-laser area 160; wherein the first laser area 130 has a first pyramid structure 130a, and the second laser area 150 has a second pyramid structure 150a.

[0153] It is worth noting that the emitter 111 is only located in the first non-laser area 140, which is conducive to ensuring that the subsequent electrode has a good current collection efficiency based on the emitter 111, while avoiding the first laser area 130 from being covered by the first doping film 101, thereby avoiding the parasitic absorption of the light incident to the first laser area 130 by the first doping film 101, improving the utilization rate of the crystalline silicon substrate 100 for light, and improving the photoelectric conversion efficiency of the photovoltaic cell. In addition, the tunneling layer 115 and the passivation layer 126 are only stacked and arranged in the second non-laser area 160, which is conducive to ensuring that the tunneling layer 115 and the passivation layer 126 have a good passivation effect on the second surface 120, while avoiding the second laser area 150 from being covered by the second doping film 103, thereby avoiding the parasitic absorption of the light incident to the second laser area 150 by the second doping film 103, and improving the utilization rate of the crystalline silicon substrate 100 for light, so as to improve the photoelectric conversion efficiency of the photovoltaic cell.

[0154] In addition, the first laser region 130 has a first pyramid structure 130a, and the second laser region 150 has a second pyramid structure 150a, which is beneficial to improving the light trapping effect of the first laser region 130 with the help of the first pyramid structure 130a, and improving the light trapping effect of the second laser region 150 with the help of the second pyramid structure 150a, thereby further improving the utilization rate of light by the first surface 110 and the second surface 120, so as to improve the photoelectric conversion efficiency of the photovoltaic cell.

[0155] Another embodiment of the present disclosure further provides a laminated battery, which includes a photovoltaic cell formed according to the preparation method provided in the above embodiment or a photovoltaic cell provided in the above embodiment. The laminated battery provided in another embodiment of the present disclosure will be described in detail below in conjunction with the accompanying drawings. It should be noted that the parts that are the same or corresponding to the above embodiment will not be repeated here.

[0156] Combined with reference Fig.10 and Fig.15 , Fig.15 A schematic diagram of the partial cross-sectional structure of a stacked cell provided in yet another embodiment of the present disclosure, the stacked cell 108 comprises: a crystalline silicon bottom cell 118, which is a photovoltaic cell formed by the preparation method provided in the aforementioned embodiment or a photovoltaic cell provided in the aforementioned embodiment; and a perovskite top cell 128, which is located on a side of the crystalline silicon substrate 100 in the crystalline silicon bottom cell 118 away from the electrode.

[0157] In some embodiments, in conjunction with reference Fig.10 and Fig.15 The crystalline silicon substrate 100 further has a second surface 120 disposed opposite to the first surface 110 , and the perovskite top cell 128 is located on a side of the first surface 110 away from the second surface 120 .

[0158] In some embodiments, the perovskite top cell 128 may include: a stacked first transmission layer, a perovskite substrate, a second transmission layer, a transparent conductive layer, and an anti-reflection layer, wherein the first transmission layer is directly opposite to the crystalline silicon bottom cell 118 .

[0159] In some embodiments, the first transport layer may be one of an electron transport layer and a hole transport layer, and the second transport layer may be the other of the electron transport layer and the hole transport layer.

[0160] Another embodiment of the present disclosure further provides a photovoltaic assembly, which includes a plurality of photovoltaic cells provided in any of the above embodiments, or a plurality of stacked cells provided in the above embodiments, and the photovoltaic assembly is used to convert received light energy into electrical energy. It should be noted that the parts that are the same or corresponding to the above embodiments can refer to the corresponding description of the above embodiments, and will not be repeated below.

[0161] refer to Fig.16 and Fig.17 The photovoltaic module includes: a battery string, which is formed by connecting a plurality of photovoltaic cells 40 provided in the above embodiment, or a plurality of laminated batteries 108 provided in the above embodiment (refer to Fig.15 ) or a plurality of photovoltaic cells 40 formed by the preparation method provided in the above embodiments; a packaging film 41 is used to cover the surface of the cell string; a cover plate 42 is used to cover the surface of the packaging film 41 away from the cell string. The photovoltaic cells 40 are electrically connected in the form of a whole piece or multiple pieces to form a plurality of cell strings, and the plurality of cell strings are electrically connected in series and / or in parallel.

[0162] in, Fig.16 A schematic diagram of a partial three-dimensional structure of a photovoltaic assembly provided in yet another embodiment of the present disclosure; Fig.17 for Fig.16 A schematic diagram of a cross-sectional structure along the cross-sectional direction MM1.

[0163] In some embodiments, the photovoltaic cell 40 includes a TOPCon cell (Tunnel Oxide Passivated Contact). In addition, the photovoltaic cell 40 may be a whole cell or a sliced ​​cell. A sliced ​​cell refers to a cell formed by a complete whole cell through a cutting process.

[0164] In some embodiments, reference Fig.16 , multiple battery strings can be electrically connected through the conductive tape 402. Fig.16Only one positional relationship between photovoltaic cells is illustrated, that is, the arrangement direction of the electrodes with the same polarity of the cells is the same, or the electrodes with positive polarity of each cell are arranged toward the same side, so that the conductive tape connects different sides of two adjacent cells. In some embodiments, the cells can also be arranged in the order of electrodes with different polarities facing the same side, that is, the electrodes of multiple adjacent cells are arranged in the order of the first polarity, the second polarity, and the first polarity, and the conductive tape connects two adjacent cells on the same side.

[0165] In some embodiments, no intervals are set between the battery cells, that is, the battery cells overlap each other.

[0166] In some embodiments, the encapsulation film 41 includes a first encapsulation layer and a second encapsulation layer, the first encapsulation layer covers one of the front side or the back side of the photovoltaic cell 40, and the second encapsulation layer covers the other of the front side or the back side of the photovoltaic cell 40. Specifically, at least one of the first encapsulation layer or the second encapsulation layer can be an organic encapsulation film such as a polyvinyl butyral (PVB) film, an ethylene-vinyl acetate copolymer (EVA) film, a polyethylene octene co-elastomer (POE) film, or a polyethylene terephthalate (PET) film.

[0167] In some cases, there is a boundary between the first encapsulation layer and the second encapsulation layer before lamination. After the lamination process, the photovoltaic module is formed and there is no longer the concept of the first encapsulation layer and the second encapsulation layer, that is, the first encapsulation layer and the second encapsulation layer have formed an integral encapsulation film 41.

[0168] In some embodiments, the cover plate 42 may be a glass cover plate, a plastic cover plate or the like with a light-transmitting function. Specifically, the surface of the cover plate 42 facing the encapsulation film 41 may be a concave-convex surface, thereby increasing the utilization rate of the incident light. The cover plate 42 includes a first cover plate and a second cover plate, the first cover plate is opposite to the first encapsulation layer, and the second cover plate is opposite to the second encapsulation layer.

[0169] Those skilled in the art can understand that the above-mentioned embodiments are specific examples for implementing the present disclosure, and in practical applications, various changes can be made to them in form and detail without departing from the spirit and scope of the embodiments of the present disclosure. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the embodiments of the present disclosure, so the protection scope of the embodiments of the present disclosure shall be based on the scope defined in the claims.

Claims

1. A method for preparing a photovoltaic cell, characterized in that: include: An initial photovoltaic cell is provided, the initial photovoltaic cell comprising: a crystalline silicon substrate, the crystalline silicon substrate having a first surface and a second surface opposite to each other along a first direction, the first surface comprising a first laser region and a first non-laser region alternately arranged along a second direction, the second surface comprising a second laser region and a second non-laser region alternately arranged along the second direction; a first doped film, a first functional film, a second doped film, and a second functional film covering the first surface and stacked along the first direction, a tunneling film, a passivation film, and a third functional film covering the second surface and stacked in a direction opposite to the first direction; At the same time, a laser treatment process is used on the first surface and the second surface to treat the portion of the initial photovoltaic cell located in the first laser area and the portion of the second laser area, so that at least the portion of the second functional film located in the first laser area is transformed into the first laser portion, and the portion of the third functional film located in the second laser area is transformed into the second laser portion; An etching process is adopted to remove the second functional film, the second doped film, the first functional film and the third functional film, remove the first doped film located in the first laser region and leave the first doped film as an emitter, and remove the passivation film and the tunneling film located in the second laser region, and leave the passivation film as a passivation layer and the tunneling film as a tunneling layer.

2. The preparation method according to claim 1, characterized in that: An orthographic projection area of ​​the first laser zone on the first surface is different from an orthographic projection area of ​​the second laser zone on the first surface, and / or an orthographic projection of the first laser zone on the first surface only partially overlaps or does not overlap with an orthographic projection of the second laser zone on the first surface.

3. The preparation method according to claim 1 or 2, characterized in that: The step of applying the laser processing process to the first surface and the second surface simultaneously comprises: A first laser treatment process is applied to the first surface, and a second laser treatment process is applied to the second surface, and the first laser treatment process and the second laser treatment process are performed simultaneously; Wherein, at least one of the laser action time, laser power, laser wavelength, laser spot size or laser scanning speed used in the first laser processing process and the second laser processing process is different.

4. The preparation method according to claim 3, characterized in that: The step of applying the first laser treatment process to the first surface includes: applying a first laser action time, a first laser power, a first laser wavelength, a first laser spot size, and a first laser scanning speed to treat a portion of the initial photovoltaic cell located in the first laser region; The step of applying the second laser treatment process to the second surface includes: applying a second laser action time, a second laser power, a second laser wavelength, a second laser spot size, and a second laser scanning speed to treat a portion of the initial photovoltaic cell located in the second laser region; Among them, the first laser action duration is greater than the second laser action duration; and / or, the first laser power is greater than the second laser power; and / or, the first laser spot size is greater than the second laser spot size; the first laser wavelength is smaller than the second laser wavelength.

5. The preparation method according to claim 3, characterized in that: In the step of applying the first laser treatment process to the first surface, only the portion of the second functional film located in the first laser region is transformed into the first laser portion; or, the portion of the second functional film located in the first laser region is transformed into the first laser portion, and the portion of the second doped film located in the first laser region is transformed into the third laser portion; In the step of applying the second laser processing process to the second surface, only the portion of the third functional film located in the second laser area is transformed into the second laser portion; or, the portion of the third functional film located in the second laser area is transformed into the second laser portion, and the portion of the passivation film located in the second laser area is transformed into the fourth laser portion.

6. The preparation method according to claim 3, characterized in that: In the step of applying the stacked first laser processing process to the first surface: a first laser emitter is used to emit a first laser; in the step of applying the second laser processing process to the second surface: a second laser emitter is used to emit a second laser; the first surface has a first side and a second side opposite to each other along the second direction, the second surface has a third side and a fourth side opposite to each other along the second direction, the first side and the third side are opposite to each other along the first direction, and the second side and the fourth side are opposite to each other along the first direction; The first direction is a horizontal direction, the first laser emitter is located on a side of the first surface away from the second surface, and the second laser emitter is located on a side of the second surface away from the first surface; and / or, the first laser emitted by the first laser emitter scans from the first side to the second side, and the second laser emitted by the second laser emitter scans from the fourth side to the third side.

7. The preparation method according to claim 1, characterized in that: The steps of adopting the etching process include: Etching the portion of the initial photovoltaic cell located in the first laser region using a first etching process to remove at least the first laser portion and the second doping film located on the first laser region; Using a second etching process to continue etching the portion of the initial photovoltaic cell located in the first laser area, so as to at least remove the first functional film located on the first laser area; A third etching process is used to simultaneously etch the first doped film located in the first laser area and the third functional film, the passivation film and the tunneling film located in the second laser area, and further texture the exposed first laser area and the second laser area so that the first laser area has a first pyramid structure and the second laser area has a second pyramid structure.

8. The preparation method according to claim 1, characterized in that: The steps of adopting the etching process include: Using a fourth etching process to etch the portion of the initial photovoltaic cell located in the first laser area to remove the first laser portion and the second doping film and the first functional film located on the first laser area, and to remove the second functional film located in the first non-laser area; The fifth etching process is used to simultaneously etch the first doped film located in the first laser zone and the third functional film, the passivation film and the tunneling film located in the second laser zone, and further texture the exposed first laser zone and the second laser zone so that the first laser zone has a first pyramid structure and the second laser zone has a second pyramid structure.

9. A photovoltaic cell, characterized in that: include: A crystalline silicon substrate, the crystalline silicon substrate having a first surface and a second surface opposite to each other along a first direction, the first surface comprising a first laser region and a first non-laser region alternately arranged in a second direction, and the second surface comprising a second laser region and a second non-laser region alternately arranged in the second direction; An emitter, located on the first non-laser region; a tunneling layer, located on the second non-laser region; A passivation layer, located on a side of the tunneling layer away from the second non-laser region; The first laser region has a first pyramid structure, and the second laser region has a second pyramid structure.

10. A laminated battery, characterized in that: include: A crystalline silicon bottom cell, wherein the crystalline silicon bottom cell is a photovoltaic cell prepared by the preparation method according to any one of claims 1 to 8, or a photovoltaic cell according to claim 9; A perovskite top cell, wherein the perovskite top cell is located on a side of the crystalline silicon substrate away from the electrode in the crystalline silicon bottom cell.

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