Method for manufacturing solar cell, solar cell and photovoltaic module

Abstract

The present disclosure relates to the photovoltaic field and provides a method for manufacturing a solar cell, a solar cell, and a photovoltaic module. The method comprises: providing a substrate comprising alternating first and second regions; forming a doped conductive layer, the doped conductive layer covering the first and second regions; performing a preheating process, wherein the preheating process heats at least the doped conductive layer in the second region to a preset temperature, and the temperature of the second region is maintained at the preset temperature before laser processing; performing laser processing, wherein a scanning area formed by a laser beam moves along a preset scanning path to irradiate the doped conductive layer in the second region; and performing a film opening process, wherein the film opening process removes the doped conductive layer in the second region. The reliability of the resulting solar cell can be improved.

Description

Technical Field

[0001] The present disclosure relates to the photovoltaic field, and in particular to a method for manufacturing a solar cell, a solar cell, and a photovoltaic module. Background Art

[0002] A solar cell is a thin, photoelectric semiconductor wafer that uses sunlight to generate electricity directly. Also known as a "solar chip" or "photocell," it can instantly output voltage and generate current in a circuit as long as it meets certain illumination conditions. In physics, this is known as solar photovoltaics (PV), or simply photovoltaics.

[0003] The production process of solar cells is divided into silicon wafer inspection, surface texturing and cleaning, diffusion bonding, laser removal of silicon glass, etching steps, anti-reflection film coating, screen printing, rapid sintering, etc.

[0004] Currently, in the process of forming solar cells, the laser power is usually high, which affects the performance of the substrate. Summary of the Invention

[0005] The embodiments of the present disclosure provide a method for manufacturing a solar cell, a solar cell, and a photovoltaic module, which can at least improve the reliability of the formed solar cell.

[0006] According to some embodiments of the present disclosure, on the one hand, the embodiments of the present disclosure provide a method for manufacturing a solar cell, including: providing a substrate, the substrate including a first area and a second area arranged alternately; forming a doped conductive layer, the doped conductive layer covering the first area and the second area; performing a preheating treatment, the preheating treatment at least heats the doped conductive layer in the second area to a preset temperature, and before performing laser processing, the temperature of the second area is maintained at the preset temperature; performing the laser processing, in which a scanning area composed of a laser beam moves along a preset scanning path to irradiate the doped conductive layer located in the second area; performing a film opening treatment, the film opening treatment removes the doped conductive layer located in the second area.

[0007] In some embodiments, heating at least the second zone to a preset temperature includes: heating the substrate as a whole.

[0008] In some embodiments, the pre-heating treatment has a preset temperature of 50° C. to 200° C., and a heating time of 10s to 100s.

[0009] In some embodiments, the solar cell is a back-contact cell, and the first zone and the second zone are alternately arranged on the back side of the back-contact cell. The laser processing includes: the preheating treatment is performed synchronously with the irradiation of the laser beam, and when the laser beam irradiates the nth second zone, the preheating treatment heats the n+1th second zone.

[0010] In some embodiments, the manufacturing method further includes: during the laser processing, obtaining the surface temperature of the doped conductive layer irradiated by the laser processing, and adjusting the heating temperature of each part of the second zone by the pre-heating treatment according to the surface temperature of the doped conductive layer.

[0011] In some embodiments, the laser processing further includes: detecting the surface temperature of the doped conductive layer irradiated by the laser processing, and adjusting the laser power, scanning speed or spot overlap rate of the laser processing.

[0012] In some embodiments, during the laser processing, the spot overlap rate is controlled to be 30% to 70%.

[0013] In some embodiments, before forming the doped conductive layer, the method further includes forming a protective layer, wherein the protective layer is located in the second region, and the protective layer is removed during the film opening process.

[0014] In some embodiments, the process parameters of the laser processing include: laser power of 20W~40W, laser scanning speed of 50000mm / s~80000mm / s, and laser frequency of 500Khz~800Khz.

[0015] In some embodiments, the film opening process includes: a first etching process, wherein the first etching process uses a first etching reagent to etch the doped conductive layer; and a second etching process, wherein the second etching process uses a second etching reagent to etch the doped conductive layer and part of the substrate.

[0016] In some embodiments, the process parameters of the first etching process include: the first etching reagent is an alkaline reagent, and the concentration of the alkaline reagent is 2%~5%, and / or, the process parameters of the second etching process include: process temperature 60℃~80℃, process time 100s~300s, the second etching reagent is an alkaline reagent with additives, and the concentration of the alkaline reagent is 3%~7%.

[0017] According to some embodiments of the present disclosure, on the other hand, embodiments of the present disclosure further provide a solar cell, which is formed by the above-mentioned method for manufacturing a solar cell, including: a substrate, the substrate including a first area and a second area arranged alternately; a doped conductive layer, the doped conductive layer is located on the surface of the first area.

[0018] In some embodiments, the second region has a pyramid base morphology, and the average size of the opening of the pyramid base morphology is 8 μm to 20 μm, and the height is less than 0.5 μm.

[0019] According to some embodiments of the present disclosure, on the other hand, the embodiments of the present disclosure further provide a photovoltaic assembly, including: a battery string, the battery string including: a plurality of solar cells formed by the manufacturing method of the solar cell as described above, or a plurality of solar cells as described above; a welding ribbon, the welding ribbon being electrically connected to at least two of the solar cells to connect adjacent solar cells in series.

[0020] The technical solution provided by the embodiments of the present disclosure has at least the following advantages: before laser processing, a preheating treatment is performed so that the second zone is maintained at a preset temperature, thereby reducing the energy required for laser processing of the doped conductive layer to reach the melting temperature threshold, thereby reducing the power of the laser processing. Moreover, since the preheating treatment makes the temperature of the second zone uniform, the uniformity of the laser processing and the mold opening process is improved, and the damage to the solar cell caused by the laser processing can be reduced, thereby improving the reliability of the formed solar cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] One or more embodiments are exemplarily illustrated by the pictures in the corresponding drawings. These exemplified descriptions do not constitute a limitation on the embodiments. Unless otherwise stated, 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 will be 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 any creative work.

[0022] Figure 1 A flow chart of a method for manufacturing a solar cell provided in one embodiment of the present disclosure;

[0023] Figures 2 to 3 A schematic structural diagram corresponding to each step of a method for manufacturing a solar cell provided in one embodiment of the present disclosure;

[0024] Figures 4 and 5 A schematic structural diagram corresponding to each step of a method for manufacturing a solar cell provided by another embodiment of the present disclosure;

[0025] Figure 6 A schematic structural diagram of a photovoltaic module provided in yet another embodiment of the present disclosure;

[0026] Figure 7 A cross-sectional view of a photovoltaic module provided in accordance with another embodiment of the present disclosure.

[0027] Description of reference numerals:

[0028] 100. Substrate; 101. Doped conductive layer; 102. Emitter; 103. Tunneling layer; 104. Front passivation layer; 105. Back passivation layer; 106. Glass layer; 107. Front electrode; 108. Back electrode.

[0029] 200, substrate; 201, doped conductive layer; 202, second doped conductive layer; 204, front passivation layer; 205, back passivation layer; 206, glass layer; 207, first electrode; 208, second electrode.

[0030] 40. Solar cell; 41. Encapsulation film; 42. Cover plate; 43. Solder ribbon. DETAILED DESCRIPTION

[0031] In the related art, laser processing is used to directly irradiate the doped conductive layer. Using the principle of photothermal coupling, the laser processing provides sufficient energy to be converted into heat to heat the surface of the doped conductive layer, so that the surface reaches a hot melt and damaged state, which speeds up the processing speed of the area in the subsequent film opening process. Based on this, the processing speed is different from that of the area that has not undergone laser processing in the subsequent film opening process, thereby completing the removal of the doped conductive layer located in the second area while retaining the doped conductive layer located in the first area. However, directly through laser processing, due to the energy distribution characteristics of the laser treatment spot, the energy of the spot overlap area is too high, the substrate is seriously amorphized, and the subsequent film opening process is hindered. In addition, dense small tower bases will appear on the surface of the substrate, affecting carrier transport and reducing FF. The small tower base band and the residual problem of film opening processing also affect the growth of the film layer in the subsequent passivation process, resulting in negative effects such as reduced Voc.

[0032] Moreover, during the laser processing process, due to the laser energy distribution characteristics (Gaussian distribution), the energy will be concentrated in the center of the spot, the energy gradient in the surrounding area will decrease, and secondary laser effects will occur in the overlapping areas of the spots. This will greatly lead to uneven heat distribution after the actual laser action, and various morphological defects will be formed after the film is opened, reducing FF and Voc, resulting in the improvement of the photoelectric conversion efficiency of the solar cell being less than expected.

[0033] The technical solution provided by the embodiments of the present disclosure has at least the following advantages: before laser processing, a preheating treatment is performed so that the second zone is maintained at a preset temperature, thereby reducing the energy required for laser processing of the doped conductive layer to reach the melting temperature threshold, thereby reducing the power of the laser processing. Moreover, since the preheating treatment makes the temperature of the second zone uniform, the uniformity of the laser processing and the mold opening process is improved, and the damage to the solar cell caused by the laser processing can be reduced, thereby improving the reliability of the formed solar cell.

[0034] In the description of the embodiments of the present disclosure, technical terms such as "first" and "second" are used solely to distinguish between different objects and should not be understood to indicate or imply relative importance or to implicitly specify the quantity, specific order, or primary and secondary relationship of the technical features indicated. In the description of the embodiments of the present disclosure, "plurality" means more than two, unless otherwise specifically defined.

[0035] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present disclosure. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0036] In the description of the embodiments of the present disclosure, the term "and / or" is merely a description of an association relationship between associated objects, indicating that three relationships may exist. For example, A and / or B can represent the following three situations: A exists, A and B exist at the same time, and B exists. In addition, the character " / " in this document generally indicates that the associated objects are in an "or" relationship.

[0037] 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).

[0038] In the description of the embodiments of the present disclosure, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present disclosure and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be understood as limiting the embodiments of the present disclosure.

[0039] In the description of the embodiments of the present disclosure, unless otherwise expressly specified or limited, technical terms such as "installed," "connected," "connected," and "fixed" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and they can refer to internal connectivity between two components or interaction between two components. Those skilled in the art can understand the specific meanings of the above terms in the embodiments of the present disclosure based on specific circumstances.

[0040] In the accompanying drawings corresponding to the embodiments of the present disclosure, the thickness and area of layers are exaggerated for better understanding and ease of description. When a component (such as a layer, film, region, or substrate) is described as being on 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. Conversely, when a component is described as being on the surface of another component, or as being formed or disposed on the surface of one component, it indicates that there is no third component between the two components. Furthermore, when a component is described as being "substantially" formed on another component, this means that the component is not formed on the entire surface (or front surface) of the other component, nor is it formed on a portion of the edge of the entire surface.

[0041] In the description of the embodiments of the present disclosure, when a component is referred to as "including" another component, unless otherwise specified, this does not exclude other components, and other components may further be included. Furthermore, when a component such as a layer, film, region, or plate is referred to as being "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 be present between them. Furthermore, when a component such as a layer, film, region, or plate is referred to as being "directly on" another component, or when a component such as a layer, film, region, or plate is located on the surface of another component, this means that no other components are located between them.

[0042] The terms used herein in the description of the various embodiments are intended only to describe the specific embodiments and are not intended to be limiting. As used in the description of the various embodiments and the appended claims, "the component" is intended to include the plural form unless the context clearly indicates otherwise. A component includes a layer, film, region, or plate.

[0043] The following describes various embodiments of the present disclosure in detail with reference to the accompanying drawings. However, those skilled in the art will appreciate that many technical details are provided in the various embodiments of the present disclosure to facilitate a better understanding of the present disclosure. However, even without these technical details and the various variations and modifications based on the following embodiments, the technical solutions claimed in the present disclosure can still be implemented.

[0044] refer to Figures 1 to 3 ,in Figure 1 A flow chart of a solar cell provided in one embodiment of the present disclosure; Figure 2 A schematic diagram of a structure for laser processing provided in one embodiment of the present disclosure; Figure 3 A schematic diagram of the structure of a solar cell formed after film opening treatment provided by one embodiment of the present disclosure.

[0045] In some embodiments, a method for manufacturing a solar cell may include: S10: providing a substrate 100 , wherein the substrate 100 includes first regions and second regions that are alternately arranged.

[0046] The method for manufacturing a solar cell may further include: S11: forming a doped conductive layer 101, wherein the doped conductive layer 101 covers the first region and the second region.

[0047] The method for manufacturing a solar cell may further include: S12: performing a preheating process, wherein the preheating process heats at least the doped conductive layer 101 in the second region to a preset temperature, and before the laser treatment is performed, the temperature of the second region is maintained at the preset temperature.

[0048] The method for manufacturing a solar cell may further include: S13: performing laser processing, wherein a scanning area formed by a laser beam moves along a preset scanning path to irradiate the doped conductive layer 101 located in the second area.

[0049] The method for manufacturing a solar cell may further include: S14: performing a film opening process, wherein the film opening process removes the doped conductive layer 101 located in the second region.

[0050] The technical solution provided by the embodiments of the present disclosure has at least the following advantages: before laser processing, preheating treatment is performed to maintain the second zone at a preset temperature, thereby reducing the energy required for laser processing of the doped conductive layer 101 to reach the melting temperature threshold, thereby reducing the power of laser processing. Moreover, since the preheating treatment makes the temperature of the second zone uniform, the uniformity of laser processing and mold opening processing is improved, and the damage to the solar cell caused by laser processing can be reduced, thereby improving the reliability of the formed solar cell.

[0051] In some embodiments, the solar cell formed is a TOPcon cell, and the doped conductive layer 101 formed can be the front emitter 102 or the back doped layer. Taking the doped conductive layer 101 formed as the back doped layer as an example, the first region of the substrate 100 is a metal region, and the second region is a non-metal region. The metal region is the region where the back electrode 108 is subsequently formed, and the non-metal region is the region offset from the back electrode 108.

[0052] It should be noted that the area where the back electrode 108 is formed here refers to the area where the back electrode 108 is projected orthogonally on the surface of the substrate 100 after the back electrode 108 is formed. The area misaligned with the back electrode 108 refers to the area where the back electrode 108 is not projected orthogonally on the surface of the substrate 100 after the back electrode 108 is formed.

[0053] After the doped conductive layer 101 is formed, it is subjected to preheating treatment, laser treatment and film opening treatment, so that selective doping can be formed on the back side, and the doped conductive layer 101 can be controlled to be formed only in the area where the electrode is formed, thereby reducing the problem of carrier recombination in the doped conductive layer 101, thereby further improving the reliability of the formed TOPCON battery.

[0054] Similarly, if the doped conductive layer 101 is the front emitter 102, the first area of the substrate 100 is a metal area, and the second area is a non-metal area. The metal area is the area where the front electrode 107 is subsequently formed, and the non-metal area is the area offset from the front electrode 107. By using pre-heating treatment, laser treatment and film opening treatment, a selective emitter can be formed on the front side, thereby improving the reliability of the TOPCON cell. The corresponding description can refer to the above description of the case where the doped conductive layer 101 is located on the back side as an example, and will not be repeated here.

[0055] Continuing with the example of the doped conductive layer 101 being the doped layer located on the back side, in some embodiments, after providing the substrate 100, an emitter 102 may be formed on the front side of the substrate 100, and a tunneling layer 103 may be formed on the back side of the substrate 100, and then the doped conductive layer 101 may be formed.

[0056] In some embodiments, the method of forming the front emitter 102 may include: performing a diffusion process on the substrate 100 to diffuse a portion of the doping element into the substrate 100 , thereby converting a portion of the substrate 100 into the emitter 102 .

[0057] The tunneling layer 103 may be formed directly on the back surface of the substrate 100 through a deposition process. The deposition process may include atomic layer deposition or chemical vapor deposition.

[0058] The method for forming the doped conductive layer 101 may include: forming an intrinsic polysilicon layer on the surface of the tunneling layer 103 using a deposition process, for example, the intrinsic polysilicon layer may be formed using an atomic layer deposition process. Then, performing a doping process on the intrinsic polysilicon layer to dope the intrinsic polysilicon layer with a doping element to form the doped conductive layer 101.

[0059] The material of the doped conductive layer 101 may also be at least one of amorphous silicon or silicon carbide.

[0060] In some embodiments, during the doping process of the intrinsic polysilicon layer, a glass layer 106 is also formed on the surface of the doped conductive layer 101. The preheating treatment, laser treatment and film opening treatment are also performed on the glass layer 106. The preheating treatment and laser treatment are used to make the glass layer 106 looser, thereby increasing the etching rate of the laser-treated glass layer 106 by the film opening treatment, thereby completing the selective etching of the doped conductive layer 101.

[0061] In some embodiments, heating at least the second zone to a predetermined temperature includes heating the entire substrate 100. Heating the entire substrate 100 can reduce the difficulty of the preheating process and the alignment difficulty, thereby requiring only placement of the solar cell on the heating platform during the formation process without the need for additional alignment.

[0062] In some embodiments, heating the second zone may also be local heating of the second zone. For example, the second zone may be directly heated by directly irradiating the second zone with a heating beam.

[0063] In some embodiments, the preheating temperature is set at 50°C to 200°C, such as 50°C, 70°C, 90°C, 100°C, 130°C, 160°C, 180°C, or 200°C, and the heating time is set at 10s to 100s, such as 10s, 20s, 30s, 40s, 50s, 60s, 70s, 80s, 90s, or 100s. If the preheating temperature is lower than 50°C, the laser power reduction capability is poor. If the preheating temperature is higher than 200°C, the heating temperature is too high, which may damage the doped conductive layer 101 substrate by the laser treatment, thereby affecting the reliability of the formed solar cell.

[0064] In some embodiments, the process parameters of laser processing include: laser power of 20W~40W, for example, 20W, 25W, 28W, 30W, 35W, 38W or 40W, etc., laser scanning speed of 50000mm / s~80000mm / s, for example, 50000mm / s, 55000mm / s, 60000mm / s, 65000mm / s, 70000mm / s, 75000mm / s or 80000mm / s, etc., laser frequency of 500Khz~800Khz, for example, 500Khz, 550Khz, 600Khz, 650Khz, 700Khz, 750Khz or 800Khz, etc.

[0065] Regarding laser power, if the laser power is less than 20W, the laser processing effect may be poor. For example, if the laser processing is to irradiate the glass layer 106, it may result in poor ability to change the porosity of the glass layer 106. If the laser power is greater than 40W, it may cause damage to the solar cell.

[0066] The laser scanning speed and laser frequency will affect the time and effect of the laser processing, and will affect the cost and performance of the solar cell. If the laser scanning speed and laser frequency are too high, the effect of the laser processing will be affected, and the laser scanning will be completed before the porosity of the glass layer 106 is completely changed. If the laser scanning speed and laser frequency are too low, the laser processing time will be too long, affecting the production cost of the solar cell.

[0067] In some embodiments, laser processing may use infrared laser, green light, ultraviolet laser, etc., and utilize laser processing to destroy the glass layer 106 so that subsequent laser processing and film opening processing can generate differential corrosion to complete selective etching.

[0068] In some embodiments, the laser treatment process further includes detecting the surface temperature of the doped conductive layer 101 irradiated by the laser treatment and adjusting the laser power, scanning speed, or spot overlap ratio of the laser treatment. In other words, the laser treatment process is adjusted based on the surface temperature during the laser treatment process. By adjusting the laser treatment process, damage to the solar cell caused by the laser treatment can be reduced.

[0069] For example, in the scanning path of laser processing, the surface temperature of the doped conductive layer 101 is measured. When it is detected that the surface temperature of the doped conductive layer 101 is abnormally uneven, the laser power, scanning speed or spot overlap rate of different laser beams can be adjusted to improve the uneven surface temperature of the doped conductive layer 101.

[0070] For laser processing, laser processing usually involves scanning the surface of the doped conductive layer 101 with multiple laser beams. Therefore, the uneven surface temperature of the doped conductive layer 101 can be improved by locally adjusting different laser beams.

[0071] As for the spot overlap rate, the overlapping portion of the spots is often a portion with relatively high energy during laser processing. Adjusting the spot overlap rate can make the laser processing of the doped conductive layer 101 relatively uniform.

[0072] In some embodiments, during the adjustment of the laser processing, the spot overlap rate is controlled to be 30% to 70%, for example, 30%, 40%, 50%, 60% or 70%, etc. For laser processing, although the spot overlap rate can be controlled to be 0, a spot overlap rate of 0 will result in a slower laser processing process. Moreover, for laser processing, the spot is usually circular. Setting the spot overlap rate to 0 will result in residual laser processing, and part of the film layer will not be irradiated by the laser, which will affect the inability to completely etch the second doped conductive layer 101 when the second doped conductive layer 101 is subsequently removed. Therefore, it is necessary to control the spot overlap rate to have a certain overlap rate. If the spot overlap rate is too high, the energy of the overlapping part will be superimposed and accumulated, which will damage the formed solar cell. Therefore, controlling the spot overlap rate to be 30% to 70% can take into account the efficiency and performance of the solar cell while improving the reliability of the solar cell.

[0073] According to an embodiment of the present disclosure, a preheating treatment is performed before the laser treatment so that the initial temperature of the doped conductive layer 101 covering the second zone is a preset temperature, thereby reducing the power of the laser treatment, improving the uniformity of heat distribution during the laser treatment, reducing the residue of the doped conductive layer 101 removed by the mold opening treatment, and at the same time, the energy of the overlapping part of the light spot will not cause the doped conductive layer 101 to become amorphous, thereby avoiding affecting the subsequent film opening treatment, further reducing the problem of the residue of the doped conductive layer 101, improving the performance of the formed solar cell, improving the photoelectric conversion efficiency by 0.01%~0.03%, reducing the thermal damage caused by the laser treatment, and reducing recombination; and the preheating treatment can also enable the laser treatment to reach the target temperature in a short time, thereby improving the processing speed of the laser treatment, correspondingly improving the production capacity of the mass production of solar cells, and improving product competitiveness.

[0074] In some embodiments, the film opening process may include: a first etching process, wherein the first etching process uses a first etching agent to etch the doped conductive layer 101; and a second etching process, wherein the second etching process uses a second etching agent to etch the doped conductive layer 101 and a portion of the substrate 100. The first etching process is used to remove surface damage of the doped conductive layer 101, and the second etching process is used to completely remove the doped conductive layer 101 and planarize the surface of the substrate 100 to facilitate uniformity in subsequent film formation.

[0075] In some embodiments, a glass layer 106 is also formed during the process of forming the doped conductive layer 101 , and the first etching process is also used to etch the glass layer 106 and a portion of the doped conductive layer 101 .

[0076] In some embodiments, the process parameters of the first etching process include: the first etching reagent is an alkaline reagent, and the concentration of the alkaline reagent is 2%~5%, for example, 2%, 3%, 4% or 5%, and / or, the process parameters of the second etching process include: process temperature 60℃~80℃, for example, 60℃, 65℃, 70℃, 75℃ or 80℃, process time is 100s~300s, for example, 100s, 150s, 200s, 250s, 270s or 300s, etc., the second etching reagent is an alkaline reagent with an additive, and the concentration of the alkaline reagent is 3%~7%.

[0077] For the first etching process, the surface of the doped conductive layer 101 is more easily etched due to the influence of the laser treatment. Therefore, the etching can be completed using an alkaline reagent with a concentration of 2% to 5%. For the second etching process, it is necessary to ensure that the doped conductive layer 101 is completely removed. In order to improve the flatness of the surface of the substrate 100 after etching, additives are added to facilitate the formation of a flatter surface of the substrate 100, thereby improving the reliability of the formed solar cell.

[0078] In the embodiment of the present disclosure, due to the reduction in the power of the laser processing, the depth of thermal damage to the surface of the substrate 100 caused by the laser processing will be reduced, and the damage to the substrate 100 with a thickness of 3μm~5μm can be reduced to 1μm~2μm, which can reduce the recombination of carriers and improve the lateral transmission effect of carriers. It can also reduce the depth of the substrate 100 removed by the second etching process, and reduce the generation of debris in the process of forming solar cells.

[0079] In some embodiments, before forming the doped conductive layer 101, the process further includes forming a protective layer, the protective layer being located in the second region and being removed during the film opening process. Forming the protective layer can reduce damage to the substrate 100 caused by the laser treatment. Furthermore, removing the protective layer during the film opening process can prevent interference with the formation of subsequent film layers, thereby further improving the performance of the solar cell.

[0080] In some embodiments, after the film opening process is completed, it can also include: forming a back passivation layer 105 and a front passivation layer 104, the back passivation layer 105 covers the surface of the doped conductive layer 101 and the surface of the substrate 100, and the front passivation layer 104 covers the surface of the emitter 102.

[0081] After forming the back passivation layer 105 and the front passivation layer 104 , a front electrode 107 and a back electrode 108 are formed. The front electrode 107 is electrically connected to the emitter 102 , and the back electrode 108 is electrically connected to the doped conductive layer 101 .

[0082] Similarly, if the doped conductive layer 101 formed is the front emitter 102, then the tunneling layer 103, the doped conductive layer 101, the front passivation layer 104 and the back passivation layer 105 are formed after pre-heating treatment, laser treatment and film opening treatment. The same or corresponding parts can refer to the above content and will not be repeated below.

[0083] Another embodiment of the present disclosure further provides a method for manufacturing a solar cell. Unlike the above embodiment, the solar cell formed in this embodiment is a back-contact solar cell. The method for manufacturing a solar cell provided by another embodiment of the present disclosure will be described below with reference to the accompanying drawings. It should be noted that the parts that are the same or corresponding to those in the above embodiment can refer to the above embodiment and will not be repeated below.

[0084] refer to Figure 4 and Figure 5 , Figure 4 A schematic diagram of a structure for performing laser processing according to another embodiment of the present disclosure; Figure 5 A schematic diagram of the structure after film opening is provided in another embodiment of the present disclosure.

[0085] The solar cell is a back-contact solar cell, and the doped conductive layer 201 formed is doped with a first doping type element. The first area of the substrate 200 is the area where the doped conductive layer 201 needs to be retained, and the second area is where a second doped conductive layer 202 with a second doping type element needs to be formed.

[0086] In some embodiments, the process of forming the doped conductive layer 201 may include: forming a semiconductor layer, and then doping the semiconductor layer to form the doped conductive layer 201 .

[0087] During the doping process, a glass layer 206 is also formed on the surface of the doped conductive layer 201 . The laser treatment can be performed on the glass layer 206 whose orthographic projection is located in the second area.

[0088] In some embodiments, the first zone and the second zone are alternately arranged on the back side of the back contact battery, and the laser processing includes: preheating treatment is performed simultaneously with irradiation of the laser beam, and when the laser beam irradiates the nth second zone, the preheating treatment heats the n+1th second zone.

[0089] In other words, the preheating treatment can be performed simultaneously with the laser treatment, thereby reducing the number of process steps in the solar cell manufacturing method and reducing the cost of the solar cell.

[0090] Moreover, for laser processing, since the speed of laser processing is relatively fast, the next area required for laser processing will be heated during the pre-heating treatment. Moreover, since the speed of laser processing is relatively fast, the temperature of the next area will not drop, and the laser processing has completed the processing of this area. Therefore, it will not affect the effect of laser processing.

[0091] In some embodiments, the method for manufacturing a solar cell further includes: during the laser processing process, obtaining the surface temperature of the doped conductive layer 201 irradiated by the laser processing, and adjusting the heating temperature of each part of the second zone in the preheating treatment according to the surface temperature of the doped conductive layer 201.

[0092] In other words, the heating effect of the pre-heating treatment on the n+1 second zones is adjusted according to the effect of the laser treatment on the nth second zone, so that the local temperature of different positions can be adjusted according to the laser treatment, thereby further improving the uniformity of the laser treatment on each position.

[0093] For example, if the surface temperature of the doped conductive layer 201 is higher in the overlapping area of the laser processing spot, the local heating temperature can be controlled to be lowered during the preheating treatment, thereby improving the uniformity of the laser processing and the reliability of the formed solar cell.

[0094] In some embodiments, after the film opening process is completed, it can also include: forming a second doped conductive layer 202 in the second area, and after forming the second doped conductive layer 202, a back passivation layer 205 and a front passivation layer 204 can also be formed, and the back passivation layer 205 covers the surface of the doped conductive layer 201 and the second doped conductive layer 202.

[0095] After forming the back passivation layer 205 and the front passivation layer 204 , a first electrode 207 and a second electrode 208 are formed. The first electrode 207 is electrically connected to the doped conductive layer 201 , and the second electrode 208 is electrically connected to the second doped conductive layer 202 .

[0096] An embodiment of the present disclosure further provides a solar cell, which can be formed by the above-mentioned solar cell manufacturing method. It should be noted that the same or corresponding parts as the above can refer to the above-mentioned embodiments and will not be repeated below.

[0097] In some embodiments, a solar cell may include a substrate including first regions and second regions that are alternately arranged.

[0098] The solar cell may include: a doped conductive layer, wherein the doped conductive layer is located on a surface of the first region.

[0099] In some embodiments, the second region has a pyramid base morphology, and the average size of the openings in the pyramid base morphology is 8 μm to 20 μm, and the height is less than 0.5 μm. By controlling the average size of the openings in the pyramid base morphology to be 8 μm to 20 μm and the height to be less than 0.5 μm, the flatness and uniformity of the back substrate can be improved, thereby improving the performance of the solar cell.

[0100] The average size here can refer to length or width.

[0101] An embodiment of the present disclosure also provides a photovoltaic module, which may include multiple solar cells formed by the manufacturing method of the solar cell in the above embodiment, or multiple solar cells as in the above embodiment. The photovoltaic module provided by an embodiment of the present disclosure will be described below in conjunction with the accompanying drawings. It should be noted that the parts that are the same or corresponding to the above can refer to the above embodiment and will not be repeated below.

[0102] refer to Figure 6 and Figure 7 ,in, Figure 6 A partial three-dimensional schematic diagram of a photovoltaic assembly provided by an embodiment of the present disclosure is shown. Figure 7 for Figure 6 A schematic partial cross-sectional view along a first cross-sectional direction BB1.

[0103] In some embodiments, a photovoltaic module includes: a cell string, the cell string including: a plurality of solar cells 40 formed by the method for forming the solar cell 40 in some or all of the above embodiments, or a plurality of solar cells as described above; a welding ribbon 43, the welding ribbon 43 being electrically connected to at least two solar cells 40 to connect adjacent solar cells 40 in series.

[0104] The photovoltaic module further includes: a packaging film 41, which is used to cover the surface of the battery string.

[0105] The photovoltaic module further includes a cover plate 42 , which is used to cover the surface of the packaging film 41 away from the cell string.

[0106] In some embodiments, the encapsulation film 41 includes a first encapsulation layer and a second encapsulation layer, wherein the first encapsulation layer covers one of the front or back sides of the solar cell, and the second encapsulation layer covers the other of the front or back sides of the solar cell. Specifically, at least one of the first encapsulation layer or the second encapsulation layer can be an organic encapsulation film such as polyvinyl butyral (PVB) film, ethylene-vinyl acetate copolymer (EVA) film, polyethylene octene co-elastomer (POE) film or polyethylene terephthalate (PET) film, or at least one of the first encapsulation layer or the second encapsulation layer can also be an EP film, EPE film or PVP film. Among them, EP film refers to a co-extruded film composed of stacked EVA film and POE film, EPE film refers to a co-extruded film formed by stacking EVA film + POE film + EVA film in sequence, and PVP film refers to a co-extruded film formed by stacking POE film + EVA film + POE film. Co-extruded films can be prepared by sequentially extruding one or more raw materials onto another already manufactured film during the film processing process, or by bonding different types of already manufactured films together.

[0107] In some cases, there is a boundary line 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.

[0108] In some embodiments, the cover plate 42 may be a light-transmitting cover plate such as a glass cover plate or a plastic cover plate. Specifically, the surface of the cover plate 42 facing the encapsulation film 41 may have a concave-convex surface or a velvet surface including multiple raised structures, thereby increasing the utilization of incident light. The cover plate 42 includes a first cover plate and a second cover plate. The first cover plate faces the first encapsulation layer, and the second cover plate faces the second encapsulation layer.

[0109] It should be noted that the cell string in the embodiment of the present disclosure is formed by connecting a plurality of back-contact cells in series. If the solar cell is a cell of other types, the structure of the photovoltaic module can be adjusted accordingly.

[0110] Those skilled in the art will appreciate that the above-described embodiments are specific examples for implementing the present disclosure, and in actual applications, various changes may 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 may make various changes and modifications without departing from the spirit and scope of the embodiments of the present disclosure. Therefore, the scope of protection of the embodiments of the present disclosure shall be based on the scope defined in the claims.

Claims

1. A method for manufacturing a solar cell, characterized in that: include: providing a substrate comprising first regions and second regions arranged alternately; forming a doped conductive layer, wherein the doped conductive layer covers the first region and the second region; Performing a preheating process, wherein the preheating process heats at least the doped conductive layer in the second region to a preset temperature, and before the laser treatment is performed, the temperature of the second region is maintained at the preset temperature; performing the laser processing, wherein a scanning area formed by a laser beam is moved along a preset scanning path to irradiate the doped conductive layer located in the second area; performing a film opening process, wherein the film opening process removes the doped conductive layer located in the second region; The solar cell is a back-contact cell, the first regions and the second regions are alternately arranged on the back side of the back-contact cell, and the laser treatment includes: the preheating treatment is performed simultaneously with the irradiation of the laser beam, and when the laser beam irradiates the nth second region, the preheating treatment heats the (n+1)th second region; The laser treatment process further includes: obtaining the surface temperature of the doped conductive layer irradiated by the laser treatment, and adjusting the heating temperature of each part of the second region in the preheating treatment according to the surface temperature of the doped conductive layer.

2. The method for manufacturing a solar cell according to claim 1, wherein: The step of heating at least the second zone to a preset temperature includes heating the substrate as a whole.

3. The method for manufacturing a solar cell according to claim 1 or 2, wherein: The preset temperature of the preheating treatment is 50° C. to 200° C., and the heating time is 10s to 100s.

4. The method for manufacturing a solar cell according to claim 1, wherein: The laser processing also includes: detecting the surface temperature of the doped conductive layer irradiated by the laser processing, and adjusting the laser power, scanning speed or spot overlap rate of the laser processing.

5. The method for manufacturing a solar cell according to claim 4, wherein: During the laser treatment, the spot overlap rate is controlled to be 30% to 70%.

6. The method for manufacturing a solar cell according to claim 1, wherein: Before forming the doped conductive layer, the method further includes forming a protective layer, wherein the protective layer is located in the second area, and the protective layer is removed during the film opening process.

7. The method for manufacturing a solar cell according to claim 1, wherein: The process parameters of the laser treatment include: laser power of 20W~40W, laser scanning speed of 50000mm / s~80000mm / s, and laser frequency of 500Khz~800Khz.

8. The method for manufacturing a solar cell according to claim 1, wherein: Film opening process includes: A first etching process, wherein the first etching process uses a first etching agent to etch the doped conductive layer; A second etching process is performed, wherein the second etching process uses a second etching agent to etch the doped conductive layer and a portion of the substrate.

9. The method for manufacturing a solar cell according to claim 8, wherein: The process parameters of the first etching process include: the first etching reagent is an alkaline reagent, and the concentration of the alkaline reagent is 2%~5%, and / or the process parameters of the second etching process include: the process temperature is 60℃~80℃, the process time is 100s~300s, the second etching reagent is an alkaline reagent with an additive, and the concentration of the alkaline reagent is 3%~7%.

10. A solar cell, characterized in that: The method for manufacturing a solar cell according to any one of claims 1 to 9, characterized in that it comprises: a substrate comprising first regions and second regions arranged alternately; A doped conductive layer is located on a surface of the first region.

11. The solar cell according to claim 10, wherein: include: The second zone has a pyramid base morphology, and the average size of the opening of the pyramid base morphology is 8 μm to 20 μm, and the height is less than 0.5 μm.

12. A photovoltaic module, characterized in that: include: A battery string, the battery string comprising: a plurality of solar cells formed by the method for manufacturing a solar cell according to any one of claims 1 to 9, or a plurality of solar cells according to any one of claims 10 to 11; a welding ribbon, the welding ribbon being electrically connected to at least two of the solar cells to connect adjacent solar cells in series; A packaging film, the packaging film is used to cover the surface of the battery string; A cover plate is used to cover the surface of the packaging film away from the battery string.

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