Solar cell and manufacturing method thereof, photovoltaic module

Abstract

The present disclosure relates to the field of photovoltaics, and provides a solar cell, a manufacturing method thereof, and a photovoltaic module. The manufacturing method of the solar cell comprises: providing an initial cell, the initial cell comprising a substrate, the substrate comprising a first region, a doped conductive region being located in the first region, a first functional layer being located on a surface of the doped conductive region away from the substrate, a second functional layer being located on a surface of the first functional layer away from the doped conductive region, the material of the first functional layer being different from that of the second functional layer; performing first laser processing, the first laser processing removing the second functional layer located in the first region; performing second laser processing, the second laser processing removing the first functional layer located in the first region to expose the doped conductive region, wherein the pulse width of the second laser processing is greater than that of the first laser processing; and forming an electrode, the electrode being in contact with the exposed doped conductive region. The performance of the formed solar cell can be improved.

Description

Technical Field

[0001] This disclosure relates to the photovoltaic field, and in particular to a solar cell and its manufacturing method, and a photovoltaic module. Background Technology

[0002] Currently, with the gradual depletion of fossil fuels, solar cells are becoming increasingly widely used as a new energy alternative. A solar cell is a device that converts solar energy into electrical energy. Solar cells utilize the photovoltaic principle to generate charge carriers, and then use electrodes to extract these carriers, thus facilitating the efficient use of electrical energy.

[0003] It is currently necessary to improve the reliability of solar cells. Summary of the Invention

[0004] This disclosure provides a solar cell and a method for manufacturing the same, which can at least improve the reliability of the solar cell.

[0005] This disclosure provides a method for manufacturing a solar cell, comprising: providing an initial solar cell, the initial solar cell including a substrate, the substrate including a first region and a second region, a doped conductive region, the doped conductive region being at least located in the first region, a first functional layer located on the surface of the doped conductive region away from the substrate, and a second functional layer located on the surface of the first functional layer away from the doped conductive region, the material of the first functional layer being different from the material of the second functional layer; performing a first laser treatment, the first laser treatment removing the second functional layer located in the first region; performing a second laser treatment, the second laser treatment removing the first functional layer located in the first region, exposing the doped conductive region, wherein the pulse width of the second laser treatment is greater than the pulse width of the first laser treatment; and forming an electrode, the electrode contacting the exposed doped conductive region.

[0006] Optionally, the single-pulse energy of the second laser treatment is less than the single-pulse energy of the first laser treatment.

[0007] Optionally, the single-pulse energy of the first laser treatment is 10 μJ to 30 μJ, and / or the single-pulse energy of the second laser treatment is 5 μJ to 15 μJ.

[0008] Optionally, the pulse width of the first laser treatment is 10ps to 50ps, and / or the pulse width of the second laser treatment is 50ps to 150ps.

[0009] Optionally, the first laser-processed spot is a flat-topped spot, and / or the second laser-processed spot is a flat-topped spot.

[0010] Optionally, the overlap rate of the laser spot processed by the second laser is less than the overlap rate of the laser spot processed by the first laser.

[0011] Optionally, the overlap rate of the laser spot in the first laser treatment is 70%~85%, and / or the overlap rate of the laser spot in the second laser treatment is 50%~70%.

[0012] Optionally, before forming the electrode, the process further includes performing a third laser treatment, wherein the third laser treatment irradiates the exposed doped conductive region.

[0013] Optionally, the first laser processing, the second laser processing, and the third laser processing are performed sequentially on each of the first regions, and after completion, the first laser processing, the second laser processing, and the third laser processing are performed on another of the first regions.

[0014] Optionally, the pulse width of the third laser processing is greater than the pulse width of the second laser processing.

[0015] Optionally, the single-pulse energy of the third laser treatment is less than the single-pulse energy of the second laser treatment.

[0016] Optionally, the spot of the third laser processing is a near-Gaussian spot.

[0017] Optionally, the first laser treatment, the second laser treatment, and the third laser treatment can be performed in the same process step.

[0018] Optionally, the wavelength of the third laser treatment is greater than the wavelength of the first laser treatment.

[0019] Optionally, before performing the second laser treatment, the method further includes: monitoring the surface irradiated by the first laser treatment, determining whether the second functional layer is penetrated, and adjusting the parameters of the laser to perform the second laser treatment when the first laser treatment penetrates the second functional layer.

[0020] Optionally, before performing the third laser treatment, the method further includes: monitoring the surface irradiated by the second laser treatment, determining whether the first functional layer is penetrated, and adjusting the parameters of the laser to perform the third laser treatment when the second laser treatment penetrates the first functional layer.

[0021] Optionally, the ratio of scanning speed to repetition frequency in the first laser processing is less than the ratio of scanning speed to repetition frequency in the second laser processing.

[0022] This disclosure also provides a solar cell formed using the solar cell manufacturing method described above.

[0023] In another aspect, this disclosure also provides a photovoltaic module, comprising: a battery string, the battery string comprising: a plurality of solar cells formed by the method described above, or, as described above, solar cells; a solder ribbon electrically connected to at least two of the solar cells to connect adjacent solar cells in series; an encapsulating film for covering the surface of the battery string; and a cover plate for covering the surface of the encapsulating film away from the battery string.

[0024] The technical solution provided in this disclosure has at least the following advantages: On the one hand, by using a first laser treatment and a second laser treatment to remove the first and second functional layers located in the first region, the electrodes can be directly contacted and electrically connected to the doped conductive regions during the subsequent electrode formation process, thereby reducing the contact resistance between the electrodes and the doped conductive regions and facilitating the transport of charge carriers. At the same time, the first and second laser treatments can improve the accuracy of grooving and reduce damage to the doped conductive regions, thereby also improving the reliability of the formed solar cell. On the other hand, for the second functional layer, the pulse width of the first laser treatment is set to be smaller so that energy is injected in a shorter time, thereby reducing the thermal damage of the first laser treatment and improving the morphology of the groove formed after removing the second functional layer. For the first functional layer, the first functional layer is removed along the groove formed after removing the second functional layer, so the pulse width is set to be larger so that the second laser treatment can melt the first functional layer and achieve the purpose of accurately removing the first functional layer. Attached Figure Description

[0025] One or more embodiments are illustrated by way of example with corresponding pictures in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Unless otherwise stated, the pictures in the accompanying drawings do not constitute a limitation on scale. In order to more clearly illustrate the technical solutions in the embodiments of this disclosure or the conventional technology, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a schematic cross-sectional view of an initial battery cell provided in an embodiment of the present disclosure;

[0027] Figure 2 This is a schematic diagram of a cross-sectional structure after undergoing a first laser treatment, provided in one embodiment of the present disclosure;

[0028] Figure 3 This is a schematic diagram of a cross-sectional structure after undergoing a second laser treatment, provided in one embodiment of the present disclosure.

[0029] Figure 4 This is a schematic diagram of a structure for forming an electrode according to an embodiment of the present disclosure;

[0030] Figure 5 This is a partial three-dimensional structural schematic diagram of a photovoltaic module provided in an embodiment of the present disclosure;

[0031] Figure 6 This is a cross-sectional structural diagram of a photovoltaic module provided in one embodiment of the present disclosure.

[0032] Explanation of reference numerals in the attached figures

[0033] 10. Initial solar cell; 100. Substrate; 110. First region; 120. Second region; 101. Doped conductive region; 102. First functional layer; 103. Second functional layer; 104. Electrode; 113. First groove; 112. Second groove; 43. Solder ribbon; 40. Solar cell; 41. Encapsulating film; 42. Cover plate. Detailed Implementation

[0034] Currently, the electrical connection between the electrode and the doped conductive region is usually controlled directly by sintering. However, this method leads to an increase in the contact resistance between the electrode and the doped conductive region.

[0035] In this embodiment, on the one hand, the first and second functional layers located in the first region are removed by first laser processing and second laser processing, so that the electrode can directly contact and connect with the doped conductive region during the subsequent electrode formation process, thereby reducing the contact resistance between the electrode and the doped conductive region and facilitating the transport of charge carriers. At the same time, the first and second laser processing can improve the accuracy of grooving and reduce damage to the doped conductive region, thereby improving the reliability of the formed solar cell. On the other hand, for the second functional layer, the pulse width of the first laser processing is set to be smaller so that energy is injected in a shorter time, thereby reducing the thermal damage of the first laser processing and improving the morphology of the groove formed after removing the second functional layer. For the first functional layer, the first functional layer is removed along the groove formed after removing the second functional layer, so the pulse width is set to be larger so that the second laser processing can melt the first functional layer and achieve the purpose of accurately removing the first functional layer.

[0036] In the description of the embodiments of this disclosure, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary or secondary relationship of the indicated technical features. In the description of the embodiments of this disclosure, "a plurality of" means two or more, unless otherwise explicitly defined.

[0037] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this disclosure. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0038] In the description of the embodiments of this disclosure, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent three cases: A exists, A and B exist simultaneously, and B exists. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0039] In the description of embodiments of this disclosure, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0040] In the description of the embodiments of this disclosure, the technical terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this disclosure and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this disclosure.

[0041] In the description of the embodiments of this disclosure, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this disclosure according to the specific circumstances.

[0042] In the accompanying drawings corresponding to the embodiments of this disclosure, the thickness and area of ​​the layers are enlarged for better understanding and ease of description. When describing a component (such as a layer, film, region, or substrate) on or on the surface of another component, the component may be "directly" located on the surface of the other component, or there may be a third component between the two components. Conversely, when describing a component on the surface of another component, or when another component is formed or disposed on the surface of a component, it indicates that there is no third component between the two components. Furthermore, when describing a component as being "generally" 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 portion of the edge of the entire surface.

[0043] In the description of embodiments of this disclosure, when a component "includes" another component, other components are not excluded unless otherwise stated, and may be further included. Furthermore, when a component such as a layer, film, region, or plate is referred to as being "on / located" on another component, it can 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 therein. Additionally, when a component such as a layer, film, region, or plate is "directly located" on another component, or when a component such as a layer, film, region, or plate is located on the surface of another component, it indicates that no other components are located therein.

[0044] The terminology used in the description of the various embodiments herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used in the description and claims of the various embodiments described, the term "component" is also intended to include the plural form unless the context clearly indicates otherwise. Components include layers, films, regions, or plates, etc.

[0045] The embodiments of this disclosure will now be described in detail with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details have been provided in the embodiments of this disclosure to facilitate a better understanding of the disclosure. However, the technical solutions claimed in this disclosure can be implemented even without these technical details and various variations and modifications based on the following embodiments.

[0046] refer to Figures 1 to 4 , Figure 1 This is a schematic cross-sectional view of an initial battery cell provided in an embodiment of the present disclosure; Figure 2 This is a schematic diagram of a cross-sectional structure after undergoing a first laser treatment, provided in one embodiment of the present disclosure; Figure 3 This is a schematic diagram of a cross-sectional structure after undergoing a second laser treatment, provided in one embodiment of the present disclosure. Figure 4 This is a schematic diagram of an electrode structure provided in an embodiment of the present disclosure.

[0047] In some embodiments, a method for manufacturing a solar cell may include: providing an initial solar cell 10, the initial solar cell 10 including a substrate 100, the substrate 100 including a first region 110 and a second region 120, a doped conductive region 101, the doped conductive region 101 being located at least in the first region 110, a first functional layer 102, the first functional layer 102 being located on the surface of the doped conductive region 101 away from the substrate 100, and a second functional layer 103, the second functional layer 103 being located on the surface of the first functional layer 102 away from the doped conductive region 101, wherein the material of the first functional layer 102 is different from the material of the second functional layer 103.

[0048] The method for manufacturing a solar cell may further include: performing a first laser treatment to remove the second functional layer 103 located in the first region 110.

[0049] The method for manufacturing a solar cell may further include: performing a second laser treatment to remove the first functional layer 102 located in the first region 110 and expose the doped conductive region 101, wherein the pulse width of the second laser treatment is greater than the pulse width of the first laser treatment.

[0050] The method of manufacturing a solar cell may also include: forming an electrode 104, wherein the electrode 104 contacts an exposed doped conductive region 101.

[0051] In this embodiment, on the one hand, the first functional layer 102 and the second functional layer 103 located in the first region 110 are removed by first laser processing and second laser processing, so that during the subsequent formation of the electrode 104, the electrode 104 can be directly contacted and electrically connected to the doped conductive region 101, thereby reducing the contact resistance between the electrode 104 and the doped conductive region 101 and facilitating the transport of charge carriers. At the same time, the first laser processing and second laser processing can improve the accuracy of grooving and reduce damage to the doped conductive region 101, thereby improving the reliability of the formed solar cell. On the other hand, for the second functional layer 103, the pulse width of the first laser processing is set to be smaller so that energy is injected in a shorter time, thereby reducing the thermal damage of the first laser processing and improving the morphology of the groove formed after removing the second functional layer 103. For the first functional layer 102, the first functional layer 102 is removed along the groove formed after removing the second functional layer 103, so the pulse width is set to be larger so that the second laser processing can melt the first functional layer 102, thereby achieving the purpose of accurately removing the first functional layer 102.

[0052] refer to Figure 1 , Figure 1 This is a schematic diagram of the structure of an initial battery cell provided in an embodiment of the present disclosure.

[0053] In some embodiments, the material of the substrate 100 can be an elemental semiconductor material. Specifically, the elemental semiconductor material is composed of a single element, such as silicon or germanium. The elemental semiconductor material can be monocrystalline, polycrystalline, amorphous, or microcrystalline (a state simultaneously possessing both monocrystalline and amorphous states is called microcrystalline). For example, silicon can be at least one of monocrystalline silicon, polycrystalline silicon, amorphous silicon, or microcrystalline silicon. The material of the substrate 100 can also be a compound semiconductor material. Common compound semiconductor materials include, but are not limited to, silicon germanide, silicon carbide, gallium arsenide, indium gallium dihydrogen phosphate, perovskite, cadmium telluride, and copper indium selenide.

[0054] The substrate 100 can be an N-type semiconductor substrate or a P-type semiconductor substrate. The N-type semiconductor substrate is doped with an N-type dopant element, which can be at least one of group V elements such as phosphorus (P), bismuth (Bi), antimony (Sb), or arsenic (As). The P-type semiconductor substrate is doped with a P-type dopant element, which can be at least one of group III elements such as boron (B), aluminum (Al), gallium (Ga), or indium (In).

[0055] The substrate 100 may include a front side and a back side, where the front side can serve as the light-receiving surface of the solar cell, used to receive incident light, and the back side can serve as the backlighting surface. In other embodiments, the solar cell is a bifacial cell, where both the front and back sides can serve as light-receiving surfaces and can be used to receive incident light. It is understood that the back side referred to in the embodiments of this disclosure can also receive incident light, but the degree of reception of incident light is weaker than that of the light-receiving surface, and is therefore defined as the back side.

[0056] The doped conductive region 101 can be located on the front and / or back. Taking the solar cell as a TOPCon cell as an example, the doped conductive region 101 located on the front can serve as the emitter of the solar cell, and the doped conductive region 101 located on the back can serve as the doped conductive layer of the solar cell.

[0057] When the doped conductive region 101 is located on the back side, a tunneling layer (not shown) is also provided between the doped conductive region 101 and the substrate 100. The tunneling layer has the effect of chemical passivation on the substrate 100 and reduces the defect state density of the substrate 100 by saturating the dangling bonds on the surface of the substrate 100.

[0058] In some embodiments, the material of the doped conductive region 101 may include at least one of amorphous silicon, polycrystalline silicon, or silicon carbide.

[0059] The materials for the tunneling layer can include dielectric materials with tunneling properties, such as silicon oxide, silicon nitride, silicon oxynitride, intrinsic amorphous silicon, and intrinsic polycrystalline silicon.

[0060] The first functional layer 102 can serve as a passivation layer. The passivation layer can include a single-layer film structure or a stacked film structure. The material of the passivation layer can be any one or more of the following materials: silicon oxide, silicon nitride, silicon oxynitride, silicon carbonitride, titanium oxide, hafnium oxide, or aluminum oxide.

[0061] The second functional layer 103 can serve as an anti-reflection layer. The anti-reflection layer has a high refractive index, which reduces reflection damage to the substrate 100. The material of the anti-reflection layer can be any one or more of silicon nitride or silicon oxynitride.

[0062] refer to Figure 2 , Figure 2 This is a schematic diagram of a structure after undergoing a first laser treatment, provided as an embodiment of the present disclosure.

[0063] In some embodiments, the single-pulse energy of the first laser processing is 10 μJ to 30 μJ, such as 10 μJ, 15 μJ, 20 μJ, 25 μJ, or 30 μJ, etc. It is understood that the single-pulse energy of the first laser processing is positively correlated with the processing capability of the first laser processing. If the single-pulse energy of the first laser processing is too low, the removal of the second functional layer 103 may be ineffective. If the single-pulse energy of the first laser processing is too high, the control of the first laser processing will be more difficult, potentially leading to over-removal. Furthermore, it may cause significant damage to the sidewalls of the second functional layer 103 exposed after removal, affecting the reliability of the formed solar cell.

[0064] In some embodiments, the pulse width of the first laser processing is 10ps to 50ps, such as 10ps to 20ps, 20ps to 30ps, 30ps to 40ps, or 40ps to 50ps, etc., or it can be 15ps, 25ps, 35ps, or 45ps, etc.

[0065] The pulse width represents the duration of laser energy release, which affects the speed at which laser energy is injected into the material and the degree of heat diffusion. The smaller the pulse width, the shorter the energy injection time, which will cause the surface of the material to be vaporized or plasmaized instantly. Before the heat can be conducted to the surroundings, the process is over. In this way, the thermal damage of the first laser treatment can be reduced, so that the inner wall of the first groove 113 formed after the first laser treatment is relatively clean and steep.

[0066] When the pulse width of the first laser treatment is less than 10 ps, ​​on the one hand, it will increase the difficulty of the process and increase the cost of the process. On the other hand, the pulse width is too small, which will make the whole process difficult to control and may remove part of the second functional layer 103, affecting the subsequent process steps. When the pulse width of the first laser treatment is greater than 50 ps, ​​it will cause the effect of removing the second functional layer 103 to decrease.

[0067] Understandably, when the pulse width is too large, the energy release is relatively slow. During the laser treatment, the heat has enough time to diffuse to the surrounding material, resulting in a severe heat-affected zone, which is the area where the material melts, recrystallizes, and produces defects. Therefore, the pulse width of the first laser treatment is set to be less than or equal to 50 ps to accelerate the removal of the second functional layer 103 and reduce the thermal damage of the first laser treatment.

[0068] In some embodiments, the laser wavelength of the first laser processing can be 355nm~532nm, such as 355nm, 400nm, 435nm, 500nm or 532nm, etc. By controlling the laser wavelength of the first laser processing to be 355nm~532nm, the processing accuracy of the first laser processing can be improved, thereby improving the reliability of the formed solar cell.

[0069] In some embodiments, the repetition frequency of the first laser processing can be 100kHz to 500kHz, for example, 100kHz, 200kHz, 300kHz, 400kHz, or 500kHz. The repetition frequency can refer to the number of pulses emitted by the laser per unit time. The higher the repetition frequency, the less time the first laser processing takes to remove the second functional layer 103. At the same time, if the repetition frequency of the first laser processing is too high, it will result in a short interval between pulses, causing heat to accumulate in the first region 110, which will cause thermal damage to the first functional layer 102 and the second functional layer 103 located in the first region 110.

[0070] Therefore, the repetition frequency of the first laser processing can be set to 100kHz~500kHz, which can improve the efficiency of the first laser processing while reducing the thermal damage to the second functional layer 103 exposed on the sidewall of the first groove 113 during the first laser processing. This improves the reliability of the process while controlling the process cost by controlling the process time.

[0071] In some embodiments, the average power of the first laser treatment can be 1W to 3W, such as 1W, 1.2W, 1.5W, 1.8W, 2W, 2.5W, or 3W, etc. The higher the average power, the better and cleaner the removal of the second functional layer 103. However, excessively high average power can lead to heat accumulation in the first region 110, causing damage to the first functional layer 102 and potentially affecting the reliability of the doped conductive region 101. Therefore, setting the average power to 1W to 3W balances the effectiveness of the first laser treatment with avoiding any impact on the reliability of the formed solar cell.

[0072] It should be noted that the average power is related to the single pulse energy and the repetition frequency. When the repetition frequency increases, the average power needs to be appropriately reduced to maintain a safe single pulse energy.

[0073] In some embodiments, the scanning speed of the first laser processing is 2m / s to 4m / s, for example, 2m / s, 2.3m / s, 2.6m / s, 3m / s, 3.5m / s, or 4m / s, etc. If the scanning speed is too slow, the laser will stay on the material per unit area for too long. If the scanning speed is too fast, the morphology of the first groove 113 formed will be poor. Therefore, in the first laser processing, controlling the scanning speed to 2m / s to 4m / s improves the reliability of the first groove 113 formed, while avoiding the accumulation of heat in the first region 110 and avoiding damage to the doped conductive region 101.

[0074] It is understandable that scanning speed and spot diameter will affect the continuity of processing. For example, if the scanning speed is too fast and the diameter is reduced, there will be a gap between the spot of the two pulses acting on the material. Therefore, setting the scanning speed of the first laser processing to 2m / s to 4m / s can take into account the morphology of the first groove 113 formed while controlling the process time of the first laser processing, thereby improving the reliability of the formed solar cell.

[0075] In some embodiments, the overlap rate of the first laser processing spot is 70%~85%, for example, 72%~77%, 77%~80%, or 80%~85%, etc., and can also be 70%, 75%, 80%, or 85%, etc. The higher the spot overlap rate, the better the processing continuity, the more uniform the width of the formed first groove 113, and the neater the boundary. At the same time, an excessively high spot overlap rate will cause heat to continuously accumulate in the first region 110. Therefore, setting the spot overlap rate of the first laser processing to 70%~85% improves the reliability of the formed first groove 113 while avoiding damage to the doped conductive region 101.

[0076] In some embodiments, the first laser processing can be a flat-topped spot. A flat-topped spot refers to a spot with a uniform beam distribution, and using a flat-topped spot can improve the reliability of the formed first groove 113.

[0077] refer to Figure 3 , Figure 3 This is a schematic diagram of a structure after undergoing a second laser treatment, provided as an embodiment of the present disclosure.

[0078] In some embodiments, the single-pulse energy of the second laser treatment is less than that of the first laser treatment. For the second laser treatment, the distance between the second laser treatment and the doped conductive region 101 is smaller, and the single-pulse energy of the second laser treatment is set to be lower, thereby avoiding damage to the doped conductive region 101.

[0079] In some embodiments, the single-pulse energy of the second laser treatment is 5 μJ to 15 μJ, for example, it can be 5 μJ to 10 μJ or 10 μJ to 15 μJ, or it can be 5 μJ, 6 μJ, 8 μJ, 10 μJ, 13 μJ or 15 μJ, etc. The single-pulse energy of the second laser treatment is positively correlated with the processing capability of the second laser treatment. At the same time, since the first functional layer 102 is easier to remove, setting the single-pulse energy of the second laser treatment to 5 μJ to 15 μJ ensures the effectiveness of removing the first functional layer 102 while avoiding affecting the doped conductive region 101.

[0080] In some embodiments, the pulse width of the second laser treatment is 50ps to 150ps, for example, 50ps to 80ps, 80ps to 120ps, or 120ps to 150ps, etc., and can also be 50ps, 60ps, 70ps, 80ps, 90ps, 100ps, 110ps, 120ps, 130ps, 140ps, or 150ps, etc. It is understood that the second laser treatment is a further removal process based on the first laser treatment, that is, removing the first functional layer 102 based on the first groove 113. During the formation of the first groove 113, it is necessary to reduce thermal damage. However, during the removal of the first functional layer 102, the second laser treatment may irradiate the surface of the doped conductive region 101. Therefore, the pulse width of the second laser treatment is set to 50ps to 150ps. Even if the surface of the doped conductive region 101 is irradiated, the second laser treatment will generate a certain amount of heat. In subsequent processes, the doped conductive region 101 will be repaired by annealing, and the second laser treatment provides the heat for the annealing repair.

[0081] In some embodiments, the laser wavelength of the second laser processing can be 355nm~532nm, such as 355nm, 400nm, 435nm, 500nm or 532nm, etc. By controlling the laser wavelength of the second laser processing to 355nm~532nm, the processing accuracy of the second laser processing can be improved, thereby improving the reliability of the formed solar cell.

[0082] In some embodiments, the repetition frequency of the second laser treatment can be 300kHz to 800kHz, for example, 300kHz, 400kHz, 500kHz, 600kHz, 700kHz, or 800kHz. Increasing the repetition frequency of the second laser treatment improves its efficiency and provides heat for subsequent annealing repair.

[0083] In some embodiments, the average power of the second laser treatment can be 1W to 2W, such as 1W, 1.2W, 1.5W, 1.8W or 2W, etc. By setting the average power of the second laser treatment to 1W to 2W, the reliability of the reliability of the formed solar cell is improved while ensuring the effect of the second laser treatment and reducing the damage to the doped conductive region 101.

[0084] In some embodiments, the scanning speed of the second laser processing is 4 m / s to 8 m / s, for example, 4 m / s, 5 m / s, 6 m / s, 7 m / s, or 8 m / s, etc. For the second laser processing, the exposed first functional layer 102 is removed along the first groove 113. Therefore, since the first groove 113 has already been formed, the difficulty of removing the first functional layer 102 is reduced. By increasing the scanning speed of the second laser processing to 4 m / s to 8 m / s, the time required for the second laser processing can be reduced, thereby reducing the overall process time of the solar cell fabrication method.

[0085] In some embodiments, the scanning speed of the second laser processing can be greater than that of the first laser processing. The first laser processing needs to locate the position of the first groove 113 and improve the morphology of the first groove 113. Therefore, the scanning speed of the first laser processing is set to be slower, which facilitates the subsequent second laser processing. The second laser processing removes the first functional layer 102 based on the first groove 113. By setting the scanning speed of the second laser processing to be faster, the process time of the entire solar cell fabrication method is reduced.

[0086] In some embodiments, the ratio of scanning speed to repetition frequency in the first laser processing is less than that in the second laser processing. The ratio of scanning speed to repetition frequency can characterize the spacing of the laser spots; the larger the ratio, the larger the spacing of the spots. In the first laser processing, it is necessary to improve the continuity of the formed first groove 113 to provide a process basis for forming the second groove 112. In the second laser processing, since the first groove 113 is well formed, it can be used as a locator, reducing the process difficulty of the second laser processing.

[0087] It should be noted that the first groove 113 is the groove formed after removing the second functional layer 103, that is, the groove formed after the first laser treatment, and the second groove 112 is the groove formed after removing the first functional layer 102, that is, the groove formed after the second laser treatment.

[0088] In some embodiments, the spot overlap rate of the second laser processing can be 50% to 70%, for example, 50% to 55%, 55% to 60%, or 60% to 70%, etc., or even 50%, 58%, 63%, or 68%, etc. The second laser processing removes the first functional layer 102 based on the first groove 113. Therefore, based on the completion of positioning, the cleaning speed of the second laser processing is improved by setting the spot overlap rate to 50% to 70%.

[0089] In some embodiments, the spot overlap rate of the second laser processing can be less than that of the first laser processing. Similarly, the first laser processing needs to locate the position of the first groove 113 and improve the morphology of the first groove 113. Therefore, the spot overlap rate of the first laser processing is set to be higher so as to remove the second functional layer 103 in a certain area relatively completely. The second laser processing removes the first functional layer 102 based on the first groove 113. By setting the spot overlap rate of the second laser processing to be smaller, the process time of the entire solar cell fabrication method is reduced. At the same time, the second laser processing is used to scan the top film layer of the doped conductive region 101. The use of a lower spot overlap rate can also avoid thermal damage in the doped conductive region 101.

[0090] In some embodiments, the second laser processing can be a flat-topped laser spot. Using a flat-topped laser spot can improve the reliability of the formed second groove 112.

[0091] In some embodiments, before performing the second laser treatment, the method further includes: monitoring the surface irradiated by the first laser treatment to determine whether the second functional layer 103 has been penetrated; if the first laser treatment penetrates the second functional layer 103, adjusting the laser parameters to perform the second laser treatment. Detecting whether the second functional layer 103 has been penetrated facilitates timely adjustment of the laser parameters, thereby improving the reliability of the formed solar cell.

[0092] In some embodiments, the method for determining whether the second functional layer 103 has been penetrated can be performed by optical emission spectroscopy, and the second functional layer 103 can be determined by detecting characteristic spectral lines.

[0093] In some embodiments, the first laser processing and the second laser processing can be performed in the same process step, that is, the entire laser process is completed in the same process step by adjusting the parameters of the laser.

[0094] In some embodiments, before forming the electrode 104, a third laser treatment is performed, in which the exposed doped conductive region 101 is irradiated by the third laser treatment. The third laser treatment can repair the doped conductive region 101. During the first and second laser treatments, the doped conductive region 101 may be damaged. Therefore, the third laser treatment is provided to repair the surface defects of the doped conductive region 101, thereby optimizing the contact interface between the doped conductive region 101 and the electrode 104.

[0095] In some embodiments, each first region 110 is subjected to a first laser treatment, a second laser treatment, and a third laser treatment in sequence. After completion, the other first region 110 is subjected to the same first laser treatment, second laser treatment, and third laser treatment. In other words, taking the formation of five second grooves 112 as an example, each location requiring groove formation is subjected to the first laser treatment, second laser treatment, and third laser treatment in sequence to form each second groove 112. By performing the first laser treatment, second laser treatment, and third laser treatment on each first region 110 in sequence, the cleanliness of removing the first functional layer 102 and the second functional layer 103 can be improved, the reliability of each formed second groove 112 can be improved, and the reliability of the formed solar cell can be improved.

[0096] In some embodiments, when performing the first laser treatment, the second laser treatment and the third laser treatment, the position of the second functional layer 103 to be removed can be located by a galvanometer. Then, the surface of the second functional layer 103 is irradiated by the first laser treatment. After the third laser treatment is completed at that position, the position of the next second functional layer 103 to be removed is located by a galvanometer.

[0097] In other embodiments, all first regions 110 may be subjected to a first laser treatment first, then all first regions 110 may be subjected to a second laser treatment, and finally all third regions may be subjected to a third laser treatment. In other words, all first grooves 113 may be formed first, then all second grooves 112 may be formed, and finally the doped conductive regions 101 may be repaired. This can reduce the process time of the solar cell manufacturing method.

[0098] In some embodiments, the wavelength of the third laser treatment can be greater than the wavelengths of the first and second laser treatments. The third laser treatment is used to repair the doped conductive region 101; therefore, setting a longer wavelength facilitates absorption by the doped conductive region 101, thereby improving the repair effect of the third laser treatment.

[0099] In some embodiments, the wavelength of the third laser treatment can be 532nm~1064nm, such as 532nm, 634nm, 782nm, 865nm, 924nm, or 1064nm, etc. By controlling the wavelength of the third laser treatment to be 532nm~1064nm, the repair effect of the third laser treatment on the doped conductive region 101 can be improved.

[0100] In some embodiments, the pulse width of the third laser treatment can be greater than the pulse width of the second laser treatment. It is understood that the third laser treatment requires a certain amount of thermal energy to repair the doped conductive region 101. Therefore, setting the pulse width of the third laser treatment to be greater than the pulse width of the second laser treatment can facilitate the repair of the doped conductive region 101.

[0101] In some embodiments, the pulse widths of the first laser treatment to the third laser treatment increase sequentially. The first laser treatment needs to avoid thermal damage to the doped conductive region 101, and the third laser treatment needs to use thermal energy to thermally repair the doped conductive region 101. Thus, the pulse widths are set to increase sequentially to meet different processing requirements.

[0102] In some embodiments, the pulse width of the third laser processing can be 150ps to 500ps, for example, 150ps to 200ps, 200ps to 300ps, 300ps to 400ps or 400ps to 500ps, or 180ps, 230ps, 280ps, 350ps, 450ps or 500ps, etc.

[0103] When the pulse width of the third laser treatment is less than 150ps, the repair effect produced by the third laser treatment will decrease. When the pulse width of the third laser treatment is greater than 500ps, it may cause the doped conductive region 101 to overheat and be damaged, resulting in a decrease in the reliability of the doped conductive region 101.

[0104] In some embodiments, the single-pulse energy of the third laser treatment can be lower than that of the second laser treatment. By reducing the single-pulse energy of the third laser treatment, damage to the doped conductive region 101 can be avoided, thereby improving the reliability of the formed solar cell.

[0105] In some embodiments, the single-pulse energy of the first laser treatment to the third laser treatment decreases sequentially. The first laser treatment requires the removal of the second functional layer 103, and the third laser treatment requires thermal repair of the doped conductive region 101 to avoid damage to the doped conductive region 101. Thus, the single-pulse energy is set to decrease sequentially to meet different processing requirements.

[0106] In some embodiments, the single-pulse energy of the third laser treatment can be 2μJ to 8μJ, for example, 2μJ, 3μJ, 4μJ, 5μJ, 6μJ, 7μJ, or 8μJ. By setting the single-pulse energy of the third laser treatment to 2μJ to 8μJ, thermal energy is provided to repair the doped conductive region 101 while avoiding damage to the doped conductive region 101 due to excessive thermal energy.

[0107] In some embodiments, the repetition frequency of the third laser processing can be 500kHz to 1000kHz, such as 500kHz, 600kHz, 700kHz, 800kHz, 900kHz, or 1000kHz, etc. Setting the repetition frequency of the third laser processing to 500kHz to 1000kHz can improve the efficiency of the third laser processing while avoiding excessive heat energy provided by the third laser processing.

[0108] Understandably, by setting the single-pulse energy of the third laser treatment to be low and the repetition frequency to be high, excessive heat energy generated in a single scan is avoided, thus preventing damage to the doped conductive region 101. At the same time, increasing the repetition frequency improves the repair effect of the third laser treatment through a small number of repair processes.

[0109] In some embodiments, the average power of the third laser treatment is 0.5W to 1.5W, for example, 0.5W, 0.7W, 1W, 1.3W, or 1.5W. Setting the average power of the third laser treatment to 0.5W to 1.5W provides thermal energy while avoiding thermal damage to the doped conductive region 101.

[0110] In some embodiments, the scanning speed of the third laser processing is 1 m / s to 3 m / s, for example, 1 m / s, 1.5 m / s, 2 m / s, 2.5 m / s, or 3 m / s, etc. For the third laser processing, repairing the doped conductive region 101 requires a certain repair time. Therefore, controlling the scanning speed of the third laser processing to 1 m / s to 3 m / s ensures both the efficiency and repair capability of the third laser processing.

[0111] In some embodiments, the spot overlap rate of the third laser treatment is greater than that of the first laser treatment. For the third laser treatment, since it is necessary to repair the doped conductive region 101, it is necessary to ensure the processing uniformity of the third laser treatment. Therefore, the spot overlap rate of the third laser treatment is set to be higher, thereby improving the repair effect on the doped conductive region 101.

[0112] In some embodiments, the spot overlap rate of the third laser processing is 80% to 90%, such as 80%, 83%, 85%, 87%, or 90%, etc. It is understood that the higher the spot overlap rate, the higher the processing uniformity of the third laser processing, and the better the repair effect. However, an excessively high spot overlap rate can cause heat to accumulate continuously at the same location, which may damage the doped conductive region 101. Therefore, setting the spot overlap rate of the third laser processing to 80% to 90% avoids situations where some doped conductive regions 101 are not repaired, and also avoids negative impacts on the doped conductive region 101.

[0113] In some embodiments, the laser spot used for the third laser treatment is a near-Gaussian spot. A near-Gaussian spot refers to a spot where the light intensity roughly conforms to a Gaussian function distribution across the cross-section, with high energy at the center and gradually decreasing towards the edges. During the repair of the doped conductive region 101, a controllable temperature gradient field is created by utilizing the high energy at the center and the low energy at the edges. The high energy at the center enables local recrystallization of the doped conductive region 101, repairing defects, while the low energy at the edges provides a smooth temperature transition, preventing a significant temperature difference between the first region 110 and the second region 120, avoiding the generation of thermal stress boundaries, and thus preventing the formation of new defects or cracks.

[0114] It is understandable that after the third laser treatment is completed, due to the use of a near-Gaussian spot, a central smooth area and a concentric ring-shaped texture structure will be formed on the surface of the treated doped conductive region 101. Since the energy is high at the center and gradually weakens at the edge during the third laser treatment, a smooth area is formed at the center and concentric circles are formed on the periphery.

[0115] In some embodiments, the first laser processing, the second laser processing, and the third laser processing are performed in the same process step. By completing the first laser processing, the second laser processing, and the third laser processing in the same process step, the number of process steps can be reduced, and the alignment difficulty between the first laser processing, the second laser processing, and the third laser processing can be reduced, thereby improving the reliability of the formed solar cell.

[0116] In some embodiments, before performing the third laser treatment, the method further includes: monitoring the surface irradiated by the second laser treatment to determine whether the first functional layer 102 has been penetrated; if the second laser treatment penetrates the first functional layer 102, adjusting the laser parameters to perform the third laser treatment. In other words, before performing the third laser treatment, it is determined whether the doped conductive region 101 is exposed, thereby avoiding irradiating the surface of the doped conductive region 101 with the laser used for repair. At the same time, by determining whether the first functional layer 102 has been penetrated, the first functional layer 102 can be completely removed, further improving the reliability of the formed solar cell.

[0117] In some embodiments, the laser parameters can be adjusted according to the judgment result. For example, when the spectrum corresponding to the doped conductive region 101 is detected on the surface, a third laser processing is used. When the feedback result obtained on the laser irradiation path changes from the doped conductive region 101 to the first functional layer 102, the third laser processing is converted to the second laser processing to remove the residual first functional layer 102.

[0118] Similarly, during the second laser processing, when the feedback result changes from the first functional layer 102 to the second functional layer 103, the second laser processing is converted to the first laser processing, thereby reducing the residue from removing the first functional layer 102 and the second functional layer 103.

[0119] refer to Figure 4 , Figure 4 This is a schematic diagram of the structure after the electrode is formed, according to an embodiment of the present disclosure.

[0120] In some embodiments, the material of electrode 104 may include silver, copper, or silver-plated copper, etc.

[0121] In this embodiment, on the one hand, the first functional layer 102 and the second functional layer 103 located in the first region 110 are removed by first laser processing and second laser processing, so that during the subsequent formation of the electrode 104, the electrode 104 can be directly contacted and electrically connected to the doped conductive region 101, thereby reducing the contact resistance between the electrode 104 and the doped conductive region 101 and facilitating the transport of charge carriers. At the same time, the first laser processing and second laser processing can improve the accuracy of grooving and reduce damage to the doped conductive region 101, thereby improving the reliability of the formed solar cell. On the other hand, for the second functional layer 103, the pulse width of the first laser processing is set to be smaller so that energy is injected in a shorter time, thereby reducing the thermal damage of the first laser processing and improving the morphology of the groove formed after removing the second functional layer 103. For the first functional layer 102, the first functional layer 102 is removed along the groove formed after removing the second functional layer 103, so the pulse width is set to be larger so that the second laser processing can melt the first functional layer 102, thereby achieving the purpose of accurately removing the first functional layer 102.

[0122] Another embodiment of this disclosure also provides a solar cell, which can be formed using the manufacturing method of solar cells as described in some or all of the above embodiments. The solar cell provided in another embodiment of this disclosure will be described below. It should be noted that the same or corresponding parts as those in the above embodiments can be referred to the above embodiments, and will not be repeated below.

[0123] In some embodiments, the solar cell can be any one of the following: PERC (Passivated Emitter and Rear Cell), PERT (Passivated Emitter and Rear Totally-diffused Cell), TOPCon (Tunnel Oxide Passivated Contact), HIT / HJT (Heterojunction Technology), or BC (Back Contact). In other embodiments, the solar cell can also be a tandem cell comprising any of the above-mentioned cells (where the top cell is a perovskite cell and the bottom cell is any one of the above-mentioned cells), or a half-cell of any of the above-mentioned cells, etc. Based on this, the initial cell described above can have a corresponding structure to the solar cell described above.

[0124] Another embodiment of this disclosure also provides a photovoltaic module, which may include multiple solar cells formed by the manufacturing method of the solar cells in the above embodiments or the solar cells as described above. The following will describe a photovoltaic module provided by an embodiment of this disclosure with reference to the accompanying drawings. It should be noted that the same or corresponding parts as described above can be referred to the above embodiments, and will not be repeated below.

[0125] refer to Figure 5 and Figure 6 ,in, Figure 5 This is a partial three-dimensional schematic diagram of a photovoltaic module provided in an embodiment of the present disclosure. Figure 6 for Figure 5 A partial cross-sectional schematic diagram along the first section direction BB1.

[0126] In some embodiments, the photovoltaic module includes: a battery string, which includes: a plurality of solar cells formed by the method described above, or a plurality of solar cells as described above; a solder ribbon 43, which is electrically connected to at least two solar cells 40 to connect adjacent solar cells 40 in series.

[0127] The photovoltaic module also includes an encapsulating film 41, which is used to cover the surface of the cell string.

[0128] The photovoltaic module also includes a cover plate 42, which is used to cover the surface of the encapsulating film 41 away from the battery string.

[0129] In some embodiments, the encapsulating film 41 includes a first encapsulating layer and a second encapsulating layer. The first encapsulating layer covers one of the front or back sides of the solar cell, and the second encapsulating layer covers the other of the front or back sides of the solar cell. Specifically, at least one of the first or second encapsulating layer can be an organic encapsulating film such as polyvinyl butyral (PVB) film, ethylene-vinyl acetate copolymer (EVA) film, polyvinyl octene elastomer (POE) film, or polyethylene terephthalate (PET) film. Alternatively, at least one of the first or second encapsulating layer can also be an EP film, an EPE film, or a PVP film. Here, 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 sequentially stacking EVA film + POE film + EVA film; 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 pre-made film during the film processing, or by bonding different types of pre-made films together.

[0130] In some cases, the first encapsulation layer and the second encapsulation layer still have a boundary line before lamination. After lamination, the photovoltaic module will no longer have the concept of a first encapsulation layer and a second encapsulation layer. That is, the first encapsulation layer and the second encapsulation layer have formed an integral encapsulation film 41.

[0131] In some embodiments, the cover plate 42 can be a glass cover plate, a plastic cover plate, or other cover plate with light-transmitting function. Specifically, the surface of the cover plate 42 facing the encapsulating film 41 can be an uneven surface or a textured surface containing multiple raised structures, thereby increasing the utilization rate of incident light. The cover plate 42 includes a first cover plate and a second cover plate, the first cover plate being opposite to the first encapsulation layer, and the second cover plate being opposite to the second encapsulation layer.

[0132] Those skilled in the art will understand that the above embodiments are specific examples of implementing this disclosure, and in practical applications, various changes in form and detail may be made without departing from the spirit and scope of the embodiments of this disclosure. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the embodiments of this disclosure; therefore, the scope of protection of the embodiments of this disclosure should be determined by the scope defined in the claims.

Claims

1. A method for manufacturing a solar cell, characterized in that, include: An initial solar cell is provided, the initial solar cell comprising a substrate including a first region and a second region, a doped conductive region at least located in the first region, a first functional layer located on the surface of the doped conductive region away from the substrate, and a second functional layer located on the surface of the first functional layer away from the doped conductive region, wherein the material of the first functional layer is different from the material of the second functional layer. A first laser process is performed to remove the second functional layer located in the first region to form a first groove, the first groove exposing the top surface of the first functional layer; A second laser process is performed to remove the first functional layer located in the first region along the first groove to form a second groove, the second groove exposing the doped conductive region, wherein the pulse width of the second laser process is greater than the pulse width of the first laser process; An electrode is formed, which is in contact with the exposed doped conductive region; Before forming the electrode, the process further includes: performing a third laser treatment, wherein the third laser treatment irradiates the exposed doped conductive region, and the pulse width of the third laser treatment is greater than the pulse width of the second laser treatment.

2. The method for manufacturing a solar cell according to claim 1, characterized in that, The single-pulse energy of the second laser treatment is less than that of the first laser treatment.

3. The method for manufacturing a solar cell according to claim 1 or 2, characterized in that, The single-pulse energy of the first laser treatment is 10 μJ to 30 μJ, and / or the single-pulse energy of the second laser treatment is 5 μJ to 15 μJ.

4. The method for manufacturing a solar cell according to claim 1, characterized in that, The pulse width of the first laser treatment is 10ps to 50ps, and / or the pulse width of the second laser treatment is 50ps to 150ps.

5. The method for manufacturing a solar cell according to claim 1, characterized in that, The first laser-processed spot is a flat-topped spot, and / or the second laser-processed spot is a flat-topped spot.

6. The method for manufacturing a solar cell according to claim 1, characterized in that, The overlap rate of the laser spot in the second laser treatment is less than that in the first laser treatment.

7. The method for manufacturing a solar cell according to claim 1 or 6, characterized in that, The overlap rate of the laser spot in the first laser treatment is 70%~85%, and / or the overlap rate of the laser spot in the second laser treatment is 50%~70%.

8. The method for manufacturing a solar cell according to claim 1, characterized in that, The first laser treatment, the second laser treatment, and the third laser treatment are performed sequentially on each of the first regions. After completion, the first laser treatment, the second laser treatment, and the third laser treatment are performed on another of the first regions.

9. The method for manufacturing a solar cell according to claim 1, characterized in that, The single-pulse energy of the third laser treatment is less than that of the second laser treatment.

10. The method for manufacturing a solar cell according to claim 1, characterized in that, The laser spot processed by the third laser is a near-Gaussian spot.

11. The method for manufacturing a solar cell according to claim 1, characterized in that, The first laser treatment, the second laser treatment, and the third laser treatment are performed in the same process step.

12. The method for manufacturing a solar cell according to claim 1, characterized in that, The wavelength of the third laser treatment is greater than the wavelength of the first laser treatment.

13. The method for manufacturing a solar cell according to claim 1, characterized in that, Before performing the second laser treatment, the method further includes: monitoring the surface irradiated by the first laser treatment, determining whether the second functional layer has been penetrated, and adjusting the parameters of the laser to perform the second laser treatment when the first laser treatment penetrates the second functional layer.

14. The method for manufacturing a solar cell according to claim 1, characterized in that, Before performing the third laser treatment, the method further includes: monitoring the surface irradiated by the second laser treatment, determining whether the first functional layer has been penetrated, and adjusting the parameters of the laser to perform the third laser treatment when the second laser treatment penetrates the first functional layer.

15. The method for manufacturing a solar cell according to claim 1, characterized in that, The ratio of scanning speed to repetition frequency in the first laser processing is less than the ratio of scanning speed to repetition frequency in the second laser processing.

16. A solar cell, characterized in that, include: It is formed using the method for manufacturing a solar cell as described in any one of claims 1 to 15.

17. A photovoltaic module, characterized in that, include: A battery string, comprising: a plurality of solar cells formed by a method for manufacturing solar cells as described in any one of claims 1 to 15, or a solar cell as described in claim 16; and a solder ribbon electrically connected to at least two of the solar cells to connect adjacent solar cells in series. An encapsulating film, the encapsulating film being used to cover the surface of the battery string; A cover plate for covering the surface of the encapsulating film away from the battery string.

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