Solar cell and its manufacturing method, solar cell module

Abstract

In the field of photovoltaic power generation, this invention provides a solar cell, a method for manufacturing the same, and a solar cell module that can improve the hot spot phenomenon of cells. [Solution] The solar cell may include a substrate on its back surface having a first protrusion, a second protrusion and a recess; a first tunnel layer covering the first protrusion; a first doped conductive layer covering the surface of the first tunnel layer; a second tunnel layer covering the second protrusion; a second doped conductive layer covering the surface of the second tunnel layer; and a third doped conductive layer including a first portion located on the side wall of the first doped conductive layer, a second portion located on the side wall of the recess, and a third portion extending from the end of the second portion toward the first protrusion, wherein the type of ions doped inside is different from that of the first doped conductive layer.

Description

Technical Field

[0001] The present disclosure relates to the field of photovoltaic power generation, and particularly to solar cells, their manufacturing methods, and solar modules.

Background Art

[0002] Crystalline silicon solar cells have evolved from BSF, PERC to PERC+. Through continuous technological innovation and improvement, the conversion efficiency of crystalline silicon solar cells has been increasing. Currently, the mass production efficiency of PERC+ has reached approximately 23.45%, approaching the theoretical limit efficiency of 24.5%. Further efficiency improvement has become difficult, and the room for improvement is limited. Currently, TOPcon cells, HJT cells, back contact cells, etc. have become new development trends for crystalline silicon solar cells and are at the forefront of current international research and industrialization.

[0003] A back contact cell refers to a crystalline silicon solar cell in which both the emitter electrode and the base electrode of the cell are located on the back of the cell. Since the back contact cell has no metal grid electrode on the front and is not shielded, the light absorption efficiency is improved, and the short-circuit current is significantly improved. And the back contact cell improves the open-circuit voltage by passivating the surface of the cell using amorphous silicon or microcrystalline silicon and their doping methods. Due to the above factors, the conversion efficiency of the back contact cell is effectively improved, and the development prospect of the back contact cell is good.

[0004] Currently, the back contact cell is affected by the hot spot phenomenon, and it is necessary to provide a manufacturing method of the cell to improve the hot spot phenomenon of the formed cell.

Summary of the Invention

[0005] Embodiments of the present disclosure provide a solar cell, its manufacturing method, and a solar module that can at least improve the hot spot phenomenon.

[0006] According to some embodiments of the present disclosure, one embodiment of the embodiments of the present disclosure includes a substrate having a back-facing front and back, the back having alternately arranged first protrusions and second protrusions and recesses located between the first protrusions and the second protrusions, a first tunnel layer covering the first protrusions, a first doped conductive layer covering the surface of the first tunnel layer, a second tunnel layer covering the second protrusions, a second doped conductive layer covering the surface of the second tunnel layer, and a first part located on the side wall of the first doped conductive layer. The device includes a third doped conductive layer comprising a second portion located on the side wall of the recess and a third portion extending away from the end of the second portion in a direction away from the first protrusion, wherein the type of ions doped inside is different from that of the first doped conductive layer, and a passivation layer covering at least the surfaces of the first doped conductive layer, the second doped conductive layer and the third doped conductive layer, wherein the thickness of the passivation layer covering the surface of the first portion is greater than the thickness of the passivation layer covering the surface of the second portion.

[0007] In other embodiments, the ratio of the thickness of the passivation layer covering the surface of the first portion to the thickness of the passivation layer covering the surface of the second portion is 1 to 0.2.

[0008] In other embodiments, the thickness of the passivation layer covering the surface of the first portion is 70 nm to 180 nm, and the thickness of the passivation layer covering the surface of the second portion is 14 nm to 180 nm.

[0009] In other embodiments, the orthographic projection of the first portion onto the surface of the substrate partially overlaps with the orthographic projection of the third portion onto the surface of the substrate.

[0010] In other embodiments, the length of the first portion in the direction from the first protrusion to the second protrusion is 0.2 μm to 3 μm.

[0011] In other embodiments, the ratio of the thickness of the first doped conductive layer to the thickness of the third doped conductive layer is 0.5 to 2.

[0012] In other embodiments, a third tunnel layer is further included, which is located between the first doped conductive layer and the third doped conductive layer, and between the third doped conductive layer and the substrate.

[0013] In another embodiment, the thickness of the passivation layer located on the side wall of the first protrusion gradually increases in the direction from the first protrusion toward the recess.

[0014] According to other embodiments of the present disclosure, another embodiment of the embodiments of the present disclosure provides a substrate comprising the steps of: providing a substrate including a back-facing front and back, the back having alternately arranged first protrusions and second protrusions and recesses located between the first and second protrusions; forming a first tunnel layer covering the first protrusions; forming a first doped conductive layer covering the surface of the first tunnel layer, further forming a first glass layer covering the surface of the first doped conductive layer and protruding from the sidewall of the first doped conductive layer; forming a second tunnel layer covering the second protrusions; and forming a second doped conductive layer covering the surface of the second tunnel layer. The process includes the steps of forming a third doped conductive layer, which comprises a first portion located on the sidewall of the first doped conductive layer and covering the surface of the first glass layer toward the substrate, a second portion located on the sidewall of the recess, and a third portion extending from the end of the second portion toward a direction away from the first protrusion, wherein the type of ions doped inside is different from that of the first doped conductive layer; removing the first glass layer; and forming a passivation layer covering the surfaces of the first doped conductive layer, the second doped conductive layer, and the third doped conductive layer, wherein the thickness of the passivation layer covering the surface of the first portion is greater than the thickness of the passivation layer covering the surface of the second portion.

[0015] In other embodiments, the step of forming the third doped conductive layer includes the steps of forming an initial second doped conductive layer that covers the surface of the second tunnel layer, the surface of the first glass layer, and further covers the surfaces of the second protrusion and the recess, and etching the initial second doped conductive layer to remove a portion of the initial second doped conductive layer located on the top surface of the first glass layer and a portion of the initial second doped conductive layer located on the surface of the recess, making the remaining initial second doped conductive layer located on the second protrusion the second doped conductive layer, and making the initial second doped conductive layer located on the recess and the first protrusion side the third doped conductive layer.

[0016] In other embodiments, the step of forming the initial second doped conductive layer further includes the step of forming a second glass layer that covers the top surface of the initial second doped conductive layer, and the step of etching the initial second doped conductive layer includes the step of performing a laser process that irradiates the second glass layer located in the first protrusion and a portion of the second glass layer located in the recess, and the step of performing an etching process that etches the second glass layer and the initial second doped conductive layer irradiated by the laser process to form the second doped conductive layer and the third doped conductive layer.

[0017] According to other embodiments of the present disclosure, yet another embodiment of the embodiments of the present disclosure provides a solar cell module comprising a plurality of solar cells and a battery string including a weld ribbon electrically connected to at least two of the solar cells and connecting adjacent solar cells in series; a sealing adhesive film covering the surface of the battery string; and a cover plate covering the surface of the sealing adhesive film away from the battery string.

[0018] The technical means according to the embodiments of this disclosure have at least the following advantages. On the one hand, a third doped conductive layer is provided, and the third doped conductive layer is electrically connected to the first doped conductive layer, thereby forming a leakage path between the third doped conductive layer and the first doped conductive layer. In this way, when a hot spot phenomenon occurs, the current is diverted by the leakage path, thereby improving the hot spot phenomenon of the solar cell. The third doped conductive layer can further improve the performance of the solar cell by having the first portion constitute a leakage path and the second and third portions exert a good passivation effect on the substrate.

[0019] On the other hand, by making the thickness of the passivation layer covering the surface of the first portion greater than the thickness of the passivation layer covering the surface of the second portion, the first portion of the third doped conductive layer forms a leakage path, and by providing a thick passivation layer on the first portion, excessive leakage can be prevented, balancing hot spot protection and electrical characteristics. By making the passivation layer located on the surface of the second portion thinner, interfacial recombination of the side walls of the first protrusion is reduced, improving the curve factor of the solar cell. [Brief explanation of the drawing]

[0020] One or more embodiments are illustrated by the corresponding drawings, and these illustrative descriptions are not limiting to the embodiments. Unless otherwise specified, the drawings are not limiting in proportion. To better illustrate the embodiments of the disclosure or the technical means in the prior art, the following drawings are briefly introduced. Clearly, the drawings in the following description are only a few embodiments of the disclosure, and those skilled in the art can obtain other drawings based on these without any creative effort.

[0021] [Figure 1] This is a schematic diagram of a solar cell according to one embodiment of the present disclosure. [Figure 2] This is an enlarged schematic diagram of the third doped conductive layer according to one embodiment of the present disclosure. [Figure 3]It is a schematic configuration diagram corresponding to each step of a method for manufacturing a solar cell according to an embodiment of the present disclosure. [Figure 4] It is a schematic configuration diagram corresponding to each step of a method for manufacturing a solar cell according to an embodiment of the present disclosure. [Figure 5] It is a schematic configuration diagram corresponding to each step of a method for manufacturing a solar cell according to an embodiment of the present disclosure. [Figure 6] It is a schematic configuration diagram corresponding to each step of a method for manufacturing a solar cell according to an embodiment of the present disclosure. [Figure 7] It is a schematic configuration diagram of a solar cell module according to an embodiment of the present disclosure. [Figure 8] It is a cross-sectional view of a solar cell module according to an embodiment of the present disclosure.

Mode for Carrying Out the Invention

[0022] As can be seen from the background art, currently, when a solar cell is locally shaded or an abnormality occurs in the cell, a hot spot phenomenon is likely to occur in the solar cell. The hot spot phenomenon refers to a phenomenon in which a certain area of the cell or assembly has a significantly higher temperature than other parts due to local overheating. Such a phenomenon is usually caused by non-uniform current distribution or excessive local resistance, and may have a great impact on the performance and lifespan of the battery. Therefore, it is necessary to improve the hot spot phenomenon of the solar cell.

[0023] Embodiments of the present disclosure provide a solar cell, a method for manufacturing the same, and a solar cell module. In the solar cell, a third doped conductive layer is provided, and by electrically connecting the third doped conductive layer to the first doped conductive layer, a leakage path is formed between the third doped conductive layer and the first doped conductive layer. In this way, when the hot spot phenomenon occurs, the leakage path is used to shunt the current, thereby improving the hot spot phenomenon of the solar cell. The third doped conductive layer can further improve the performance of the solar cell by having a first portion that forms a leakage path and second and third portions that exhibit a good passivation effect on the substrate. On the other hand, further, the thickness of the passivation layer covering the surface of the first portion is made larger than the thickness of the passivation layer covering the surface of the second portion, and a leakage path is formed by the first portion of the third doped conductive layer, and a thick passivation layer is provided on the first portion to prevent excessive leakage, and a balance between hot spot protection and electrical characteristics can be achieved. The passivation layer located on the surface of the second portion is thinned to reduce the interface recombination on the sidewall of the first protrusion and improve the fill factor of the solar cell.

[0024] In the description of the embodiments of the present disclosure, technical terms such as "first" and "second" are only used to distinguish different objects, and it should not be understood as indicating or implying relative importance, or implicitly indicating the number of the indicated technical features, a specific order, or a primary-secondary relationship. In the description of the embodiments of the present disclosure, "a plurality" means two or more unless there is a clear and specific limitation.

[0025] As used herein, the phrase "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the present disclosure. The phrase that appears in various places in this specification does not necessarily refer to the same embodiment, nor is it an exclusive or alternative embodiment independent of other embodiments. A person skilled in the art will explicitly and implicitly understand that the embodiments described in this specification can be combined with other embodiments.

[0026] In the description of the embodiments of this disclosure, the term "and / or" is a related relationship that describes related objects, indicating that there may be three possible relationships. For example, A and / or B can represent three cases: A exists, A and B exist simultaneously, and B exists. Also, the letter " / " in this specification generally indicates that the related objects before and after are in an "or" relationship.

[0027] In the description of the embodiments of this disclosure, the term "multiple" means two or more (including two), similarly, "multiple sets" means two or more sets (including two sets), and "multiple sheets" means two or more (including two sheets).

[0028] In the description of the embodiments of this disclosure, the orientations or positional relationships indicated by technical terms such as "center," "vertical direction," "horizontal direction," "length," "width," "thickness," "top," "bottom," "front," "back," "left," "right," "vertical," "horizontal," "top," "bottom," "inside," "outside," "clockwise," "counterclockwise," "axial direction," "radial direction," and "circumferential direction" are based on the orientations or positional relationships shown in the drawings and are merely for the purpose of easily describing and simplifying the embodiments of this disclosure. They do not indicate or suggest that the shown devices or parts have a specific orientation or must be configured and operated in a specific orientation, and should not be understood as limiting the embodiments of this disclosure.

[0029] In the description of the embodiments of this disclosure, unless otherwise explicitly provided and limited, the technical terms “attachment,” “connection,” “connection,” and “fixing” should be understood in a broad sense, and may include, for example, fixed connections, removable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections via an intermediate medium; and internal communication between two parts or interaction relationships between two parts. Those skilled in the art will be able to understand the specific meaning of the above terms in the embodiments of this disclosure depending on the specific circumstances.

[0030] In the drawings corresponding to the embodiments of this disclosure, the thickness and area of ​​the layers are shown enlarged for better understanding and to facilitate explanation. When one component (e.g., a layer, thin film, region, or substrate) is described as being on or on the surface of another component, the component may be located "directly" on the surface of the other component, and a third component may exist between the two components. Conversely, when one component is described as being on the surface of another component, or as being formed or provided on the surface of one component, it indicates that there is no third component between the two components. Also, when one component is described as being "substantially" formed on the surface of another component, it means that the component is not formed on the entire surface (or front surface) of the other component, nor on any part of the edge of the entire surface.

[0031] In the descriptions of the embodiments of this disclosure, when one component "includes" another component, unless otherwise specified, this does not exclude other components, and other components may be included. Also, when a component such as a layer, film, region, or plate is described as "being present / located" on another component, that component may be located "directly" on the other component (i.e., located on the surface of the other component with no other components between them), or other components may be present between them. Furthermore, 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 present between them.

[0032] The terms used in the description of the various embodiments described herein are for the purpose of describing specific embodiments only and are not intended to limit them. As used in the description of the various embodiments described and in the appended claims, “the parts” is intended to be plural unless the context explicitly indicates otherwise. Members include members such as layers, films, regions or plates.

[0033] The embodiments of this disclosure will be described in detail below with reference to the drawings. Those skilled in the art will understand that the embodiments of this disclosure provide many technical details to help the reader better understand the disclosure. However, the technical means seeking protection of this disclosure can be realized without these technical details or the various changes and modifications based on the embodiments below.

[0034] Figure 1 is a schematic diagram of a solar cell according to one embodiment of the present disclosure, and Figure 2 is an enlarged schematic diagram of a third doped conductive layer according to one embodiment of the present disclosure.

[0035] As shown in Figures 1 and 2, in other embodiments, the solar cell may include a substrate 100 having a back-facing front 110 and a back 120, the back 120 of which is provided with alternately arranged first protrusions 130 and second protrusions 140, and a recess 150 located between the first protrusions 130 and the second protrusions 140.

[0036] The solar cell may further include a first tunnel layer 101 that covers the first protrusion 130.

[0037] The solar cell may further include a first doped conductive layer 102 that covers the surface of the first tunnel layer 101.

[0038] The solar cell may further include a second tunnel layer 103 that covers the second protrusion 140.

[0039] The solar cell may further include a second doped conductive layer 104 that covers the surface of the second tunnel layer 103.

[0040] The solar cell may further include a third doped conductive layer 105, which comprises a first portion 115 located on the sidewall of the first doped conductive layer 102, a second portion 125 located on the sidewall of the recess 150, and a third portion 135 extending from the end of the second portion 125 toward the first projection 130, wherein the type of ions doped inside is different from that of the first doped conductive layer 102.

[0041] The solar cell may further include a passivation layer 106 covering at least the surfaces of the first doped conductive layer 102, the second doped conductive layer 104, and the third doped conductive layer 105, wherein the thickness of the passivation layer 106 covering the surface of the first portion 115 is greater than the thickness of the passivation layer 106 covering the surface of the second portion 125.

[0042] In the embodiments of this disclosure, a third doped conductive layer 105 is provided, and the third doped conductive layer 105 is electrically connected to the first doped conductive layer 102, thereby forming a leakage path between the third doped conductive layer 105 and the first doped conductive layer 102. In this way, when a hot spot phenomenon occurs, the current is diverted by the leakage path, thereby improving the hot spot phenomenon of the solar cell. The third doped conductive layer 105 can further improve the performance of the solar cell by having the first portion 115 form a leakage path and the second portion 125 and third portion 135 exert a good passivation effect on the substrate 100. On the other hand, the thickness of the passivation layer 106 covering the surface of the first portion 115 is made greater than the thickness of the passivation layer 106 covering the surface of the second portion 125, and the first portion 115 of the third doped conductive layer 105 forms a leak path. By providing a thick passivation layer 106 on the first portion 115, excessive leakage is prevented, and a balance can be struck between hot spot protection and electrical characteristics. By making the passivation layer 106 located on the surface of the second portion 125 thinner, interfacial recombination of the sidewall of the first protrusion 130 is reduced, improving the curvature factor of the solar cell.

[0043] The substrate 100 receives incident light and generates photogenerating carriers. In other embodiments, the substrate 100 may be a semiconductor substrate, such as silicon, germanium, silicon-germanium, or insulating silicon.

[0044] In other embodiments, the material of the substrate 100 may 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 may be in a single-crystal state, a polycrystalline state, an amorphous state, or a microcrystalline state (a state having both single-crystal and amorphous states is called a microcrystalline state). For example, silicon may be at least one of single-crystal silicon, polycrystalline silicon, amorphous silicon, or microcrystalline silicon. If the material of the substrate 100 is silicon, the material of the substrate 100 may include at least one of single-crystal silicon, polycrystalline silicon, amorphous silicon, or microcrystalline silicon.

[0045] The substrate 100 may be an N-type semiconductor substrate or a P-type semiconductor substrate. The N-type semiconductor substrate is doped with an N-type doped element, and the N-type doped element may be any one of the 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 doped element, and the P-type doped element may be any one of the Group III elements such as boron (B), aluminum (Al), gallium (Ga), or indium (In).

[0046] If the solar cell is a single-sided battery, the substrate 100 has its front surface 110 as the light-receiving surface that receives incident light, and its back surface 120 as the back.

[0047] The first protrusion 130 may correspond to either the N region or the P region of the cell, the second protrusion 140 may correspond to the other of the N region or the P region of the cell, and the recess 150 is the distance between the N region and the P region.

[0048] In other embodiments, the recess 150 may include a first transition region 160, a flat region 170, a second transition region 180, and a texture region 190. The first transition region 160 is adjacent to the first protrusion 130, and the second portion of the third doped conductive layer 105 may be located on the surface of the first transition region 160. The flat region 170 is adjacent to the first transition region 160, and the third portion 135 of the third doped conductive layer 105 may be located in the flat region 170. The second transition region 180 connects the flat region 170 and the texture region 190, and the texture region 190 has a pyramidal shape.

[0049] The flat region 170 can support a portion of the third doped conductive layer 105, the second transition region 180 forms a transition bridge between the flat region 170 and the textured region 190, the difference in morphology between the flat region 170 and the textured region 190 could cause mechanical stress concentration, the second transition region 180 distributes stress through its gradually changing surface morphology, avoiding cracking or damage to the cell due to stress concentration near the boundary, and the textured region 190 enhances the light reflection capability within the recess 150, improving the light absorption capability of the solar cell by reflecting light incident on the back surface 120 back to the substrate 100.

[0050] In other embodiments, the material of the first tunnel layer 101 may be silicon oxide, silicon nitride, or silicon oxynitride, and the first tunnel layer 101 can passivate the substrate 100 without affecting carrier transmission and reduce carrier transmission loss by buffering the interfacial tension between the substrate 100 and the first doped conductive layer 102.

[0051] The first doped conductive layer 102 may be doped polycrystalline silicon, which has good electrical conductivity and can effectively transmit carriers, and has good ohmic contact with the subsequently formed first electrode 108, thereby reducing the contact resistance between the first electrode 108 and the first doped conductive layer 102.

[0052] The material of the second tunnel layer 103 may be the same as the material of the first tunnel layer 101, for example, silicon oxide, silicon nitride, or silicon oxynitride, thereby reducing the types of materials used in the solar cell, reducing the processes required for solar cell formation, and lowering the difficulty of solar cell formation. The material of the second tunnel layer 103 may also be intrinsic amorphous silicon, which itself has excellent surface passivation properties and can significantly reduce carrier recombination on the back surface. Hydrogen atoms in intrinsic amorphous silicon passivate dangling bonds and reduce the surface state density, thereby reducing recombination and improving the open-circuit voltage and curve factor.

[0053] The material of the second doped conductive layer 104 may be the same as that of the first doped conductive layer 102. Similarly, this can reduce the number of materials used in the solar cell, reduce the processes required for solar cell formation, and lower the difficulty of solar cell formation. The material of the second doped conductive layer 104 may also be doped amorphous silicon.

[0054] When the second tunnel layer 103 is intrinsic amorphous silicon, the material of the second doped conductive layer 104 is doped amorphous silicon. When the second tunnel layer 103 is silicon oxide, silicon nitride, or silicon oxynitride, the material of the second doped conductive layer 104 is doped polycrystalline silicon.

[0055] In other embodiments, a third tunnel layer 107 is further included, located between the first doped conductive layer 102 and the third doped conductive layer 105, and between the third doped conductive layer 105 and the substrate 100. The third tunnel layer 107 can perform a passivation function without affecting carrier transmission and can improve the performance of the solar cell.

[0056] The material of the third tunnel layer 107 may be the same as the material of the second tunnel layer 103. In this way, the third tunnel layer 107 and the second tunnel layer 103 can be formed in the same process step, and the number of process steps for forming the solar cell can be reduced.

[0057] The third doped conductive layer 105 and the second doped conductive layer 104 are made of the same material, and similarly, after forming the third tunnel layer 107 and the second tunnel layer 103 in the same process step, the third tunnel layer 107 and the second tunnel layer 103 can be separated by other process steps.

[0058] In other embodiments, the ratio of the thickness of the first doped conductive layer 102 to the thickness of the third doped conductive layer 105 is 0.5 to 2, for example, 1, 1.1, 1.2, 1.3, 1.4, 1.5, or 1.8. The first doped conductive layer 102 collects photogenerated carriers, and the greater the thickness, the higher the efficiency of photogenerated carrier collection. The third doped conductive layer 105 is mainly intended for leakage, and the greater the thickness, the higher the leakage capability and the greater the effect of improving the hot spot phenomenon. If the ratio of the thickness of the first doped conductive layer 102 to the thickness of the third doped conductive layer 105 is less than 0.5, the leakage effect of the third doped conductive layer 105 is too high, which may reduce the photoelectric conversion efficiency of the solar cell. If the ratio of the thickness of the first doped conductive layer 102 to the thickness of the third doped conductive layer 105 is greater than 2, that is, if the thickness of the third doped conductive layer 105 is too thin, it results in low leakage capacity and a low effect on improving the leakage of the solar cell.

[0059] In other embodiments, the ratio of the thickness of the first doped conductive layer 102 to the thickness of the third doped conductive layer 105 is 1 to 1.5. In the solar cell manufacturing process, forming the second doped conductive layer 104 and the third doped conductive layer 105 in the same process step reduces the number of process steps in the solar cell manufacturing method and thus reduces costs. Based on this, setting the ratio of the thickness of the first doped conductive layer 102 to the thickness of the third doped conductive layer 105 to 1 to 1.5 takes into account the need for the photogenerated carrier collection function in the second doped conductive layer 104.

[0060] In other embodiments, the orthographic projection of the first portion 115 onto the surface of the substrate 100 partially overlaps with the orthographic projection of the third portion 135 onto the surface of the substrate 100. In other words, the first portion 115 partially shields the third portion 135. First, the overlap of the projection of the first portion 115 and the projection of the third portion 135 indicates that the third doped conductive layer 105 extends from the first protrusion 130 to the recess 150, and that the third doped conductive layer 105 is continuous between the first protrusion 130 and the recess 150. This continuity ensures that the current is uniformly distributed between the first protrusion 130 and the recess 150, thus avoiding localized current concentration.

[0061] As can be understood, the recess 150 prevents a short circuit between the first protrusion 130 and the second protrusion 140 by functioning as a region separating them. However, if the recess 150 were completely insulated, the potential difference could cause charge accumulation or localized electric field concentration, potentially leading to leakage or hot spots. Therefore, by providing a third doped conductive layer 105 extending from the first protrusion 130 to the recess 150, a slightly conductive leakage path is formed between the first protrusion 130 and the recess 150. This leakage path has high resistance and does not significantly shunt the main current, thus providing a bypass.

[0062] In other embodiments, the length of the first portion 115 in the direction from the first protrusion 130 to the second protrusion 140 is 0.2 μm to 3 μm, for example, 0.3 μm, 0.5 μm, 0.7 μm, 0.9 μm, 1 μm, 1.5 μm, 2 μm, 2.5 μm, or 2.8 μm. As can be understood, if the length of the first portion 115 is too long, it will affect the length of the third portion 135 formed during the formation of the third doped conductive layer 105. Therefore, if the first portion 115 is too long, the length of the third doped conductive layer 105 will be too long, which may affect the photoelectric conversion efficiency of the solar cell, and if the length of the first portion 115 is too short, it may affect the leakage capability of the first portion 115 itself, which may reduce the effect of improving the hot spot phenomenon of the solar cell.

[0063] In other embodiments, the length of the first portion 115 is less than 1 μm, which ensures that the third doped conductive layer 105 has a certain leakage capability and avoids the third doped conductive layer 105 affecting the collection of carriers in the solar cell.

[0064] In other embodiments, the ratio of the thickness of the passivation layer 106 covering the surface of the first portion 115 to the thickness of the passivation layer 106 covering the surface of the second portion 125 is 1 to 0.2.

[0065] If the ratio of the thickness of the passivation layer 106 covering the surface of the first part 115 to the thickness of the passivation layer 106 covering the surface of the second part 125 is less than 0.2, i.e., if the passivation layer covering the surface of the second part is too thick, the excessively thick passivation layer 106 may increase the carrier diffusion pathway and increase the recombination probability. If the ratio of the thickness of the passivation layer 106 covering the surface of the first part 115 to the thickness of the passivation layer 106 covering the surface of the second part 125 is greater than 1, i.e., if the passivation layer covering the surface of the first part is too thin, it may cause localized failure in the first part and reduce the reliability of the solar cell.

[0066] In other embodiments, the thickness of the passivation layer 106 covering the surface of the first portion 115 is 70 nm to 180 nm, for example, 80 nm, 90 nm, 100 nm, 110 nm, 120 nm, 130 nm, 140 nm, 150 nm, 160 nm, or 170 nm, and the thickness of the passivation layer 106 covering the surface of the second portion 125 is 14 nm to 180 nm, for example, 20 nm, 30 nm, 40 nm, 50 nm, 70 nm, 100 nm, 150 nm, or 170 nm.

[0067] To understand this, if the thickness of the passivation layer 106 covering the surface of the first portion 115 is less than 70 nm, it may not be able to effectively suppress surface recombination; if the thickness of the passivation layer 106 covering the surface of the first portion 115 is greater than 180 nm, the passivation layer may be too thick, affecting the leak capability of the first portion 115 and potentially reducing its leak capability; if the thickness of the passivation layer 106 covering the surface of the second portion 125 is less than 14 nm, it may reduce the passivation capability of the passivation layer 106 and increase carrier recombination; and if the thickness of the passivation layer covering the surface of the second portion 125 is greater than 180 nm, it may suppress the sidewall leak function and impair coordination with the first portion 115.

[0068] In other embodiments, the thickness of the passivation layer 106 located on the surface of the second portion gradually increases in the direction from the first projection 130 toward the recess 150. In other words, the thickness of the passivation layer 106 increases as it approaches the recess 150, which is typically a high-resistance region where charge tends to accumulate and causes localized electric field distortion. Increasing the thickness of the portion of the passivation layer 106 adjacent to the recess 150 suppresses leakage at the edge of the recess 150, and in the solar cell manufacturing process, the closer to the sidewall of the recess 150, the more susceptible it is to damage. Increasing the thickness of the portion of the passivation layer 106 adjacent to the recess 150 helps allow carriers to flow more smoothly from the first projection 130 to the electrode without being trapped at the sidewall.

[0069] In other embodiments, the system further includes a first electrode 108 electrically connected to the first doped conductive layer 102 and a second electrode 109 electrically connected to the second doped conductive layer 104.

[0070] In the embodiments of this disclosure, a third doped conductive layer 105 is provided, and the third doped conductive layer 105 is electrically connected to the first doped conductive layer 102, thereby forming a leakage path between the third doped conductive layer 105 and the first doped conductive layer 102. In this way, when a hot spot phenomenon occurs, the current is diverted by the leakage path, thereby improving the hot spot phenomenon of the solar cell. The third doped conductive layer 105 can further improve the performance of the solar cell by having the first portion 115 form a leakage path and the second portion 125 and third portion 135 exert a good passivation effect on the substrate 100. On the other hand, the thickness of the passivation layer 106 covering the surface of the first portion 115 is made greater than the thickness of the passivation layer 106 covering the surface of the second portion 125, and the first portion 115 of the third doped conductive layer 105 forms a leak path. By providing a thick passivation layer 106 on the first portion 115, excessive leakage is prevented, and a balance can be struck between hot spot protection and electrical characteristics. By making the passivation layer 106 located on the surface of the second portion 125 thinner, interfacial recombination of the sidewall of the first protrusion 130 is reduced, improving the curvature factor of the solar cell.

[0071] Another embodiment of this disclosure further provides a method for manufacturing a solar cell, which may be used for the solar cells in some or all of the above embodiments. The method for manufacturing a solar cell according to another embodiment of this disclosure will be described below with reference to the drawings. Note that the same or corresponding parts of the above embodiments can be referred to in the corresponding descriptions of the above embodiments, and therefore the descriptions will be omitted below.

[0072] Figures 3 to 6 are schematic diagrams corresponding to each step of the method for manufacturing a solar cell according to one embodiment of the present disclosure.

[0073] As shown in Figures 3 to 6, in other embodiments, the method for manufacturing a solar cell may include the step of providing a substrate 100 which includes a back-facing front 110 and a back 120, the back 120 of which is provided with alternately arranged first protrusions 130 and second protrusions 140 and a recess 150 located between the first protrusions 130 and the second protrusions 140.

[0074] The method for manufacturing the solar cell may further include the step of forming a first tunnel layer 101 that covers the first protrusion 130.

[0075] A method for manufacturing a solar cell includes the step of forming a first doped conductive layer 102 that covers the surface of a first tunnel layer 101, and further includes the step of forming a first glass layer 200 that covers the surface of the first doped conductive layer 102 and protrudes from the side wall of the first doped conductive layer 102.

[0076] The method for manufacturing the solar cell may further include the step of forming a second tunnel layer 103 that covers the second protrusion 140.

[0077] The method for manufacturing a solar cell may further include the step of forming a second doped conductive layer 104 that covers the surface of the second tunnel layer 103.

[0078] A method for manufacturing a solar cell may further include the step of forming a third doped conductive layer 105, which includes a first portion 115 located on the side wall of the first doped conductive layer 102 and covering the surface of the first glass layer 200 facing the substrate 100, a second portion 125 located on the side wall of the first protrusion 130, and a third portion 135 located in the recess 150, and in which the type of ions doped inside is different from that of the first doped conductive layer 102.

[0079] The method for manufacturing the solar cell may further include the step of removing the first glass layer 200.

[0080] The method for manufacturing a solar cell may further include the step of forming a passivation layer 106 that covers the surfaces of the first doped conductive layer 102, the second doped conductive layer 104, and the third doped conductive layer 105, wherein the thickness of the passivation layer 106 covering the surface of the first portion 115 is greater than the thickness of the passivation layer 106 covering the surface of the second portion 125.

[0081] By forming a third doped conductive layer 105 and configuring a leak path with the third doped conductive layer 105, the hot spot phenomenon of the solar cell is improved by diverting the current through the leak path when a hot spot phenomenon occurs. Furthermore, the second portion 125 and the third portion 135 of the third doped conductive layer 105 exert a good passivation effect on the substrate 100, thereby improving the performance of the solar cell. On the other hand, a passivation layer 106 is further formed, and the thin passivation layer 106 on the surface of the second portion 125 reduces interfacial recombination of the side wall of the first protrusion 130, improving the curve factor of the solar cell.

[0082] As shown in Figures 3 and 4, the first tunnel layer 101 and the first doped conductive layer 102 are formed.

[0083] As shown in Figure 3, a first tunnel layer 101 and an initial first doped conductive layer 112 are formed. The first tunnel layer 101 covers the back surface 120, and the initial first doped conductive layer 112 covers the surface of the first tunnel layer 101.

[0084] In other embodiments, the step of forming the initial first doped conductive layer 112 may include a step of forming a polycrystalline silicon layer by deposition and then converting the polycrystalline silicon layer into the initial first doped conductive layer 112 by a diffusion process, and further including a step of forming the first glass layer 200.

[0085] As shown in Figure 4, the first doped conductive layer 102 is formed.

[0086] In other embodiments, the step of forming the first doped conductive layer 102 may include the step of performing laser treatment on the surface of the first glass layer 200 and the step of performing wet etching. Because a portion of the first glass layer 200 is treated with laser, a portion of the first glass layer 200 is modified and removed during wet etching, and a portion of the initial first doped conductive layer 112 and the first tunnel layer 101 and consequently the substrate 100 are partially etched to form a first protrusion 130, a recess 150 and a second protrusion 140 of different heights.

[0087] To make it easier to understand, during wet etching, the etching process is carried out not only in the vertical direction but also in the horizontal direction, and in this way, after wet etching, a portion of the first glass layer 200 protrudes from the side wall of the first projection 130.

[0088] As shown in Figures 5 and 6, a second tunnel layer, a second doped conductive layer, and a third doped conductive layer are formed.

[0089] In other embodiments, the step of forming the third doped conductive layer 105 includes the steps of forming an initial second doped conductive layer 114 that covers the surface of the second tunnel layer 103, the surface of the first glass layer 200, and further covers the surfaces of the second protrusion 140 and the recess 150, and etching the initial second doped conductive layer 114 to remove a portion of the initial second doped conductive layer 114 located on the top surface of the first glass layer 200 and the initial second doped conductive layer 114 located on the surface of the recess 150, making the remaining initial second doped conductive layer 114 located on the second protrusion 140 the second doped conductive layer 104, and making the initial second doped conductive layer 114 located on the recess 150 and the first protrusion 130 side the third doped conductive layer 105. By forming the second doped conductive layer 104 and the third doped conductive layer 105 in the same process steps, the number of process steps for forming the solar cell can be reduced, thereby reducing the cost of the solar cell.

[0090] As shown in Figure 5, a second tunnel layer and an initial second doped conductive layer are formed.

[0091] In other embodiments, the second tunnel layer 103 may be formed by total deposition, and the second tunnel layer 103 covers the exposed surface of the first glass layer 200, covers the side walls of the first tunnel layer 101 and the first doped conductive layer 102, and covers the exposed surface of the substrate 100.

[0092] Subsequently, an initial second doped conductive layer 114 is formed to cover the surface of the second tunnel layer 103.

[0093] In other embodiments, the step of forming the initial second doped conductive layer 114 is a step of forming a polycrystalline silicon layer by deposition and then converting the polycrystalline silicon layer into the initial second doped conductive layer 114 by a diffusion process, and may further include the step of forming a second glass layer 201.

[0094] As shown in Figure 6, a second doped conductive layer and a third doped conductive layer are formed.

[0095] In other embodiments, the step of etching the initial second doped conductive layer 114 includes the steps of performing a laser process that irradiates the second glass layer 201 located in the first protrusion 130 and a portion of the second glass layer 201 located in the recess 150, and the steps of performing an etching process that etches the second glass layer 201 and the initial second doped conductive layer 114 irradiated by the laser process to form the second doped conductive layer 104 and the third doped conductive layer 105. By modifying the second glass layer 201 with the laser process, the mold opening of the second glass layer 201 is completed, and the subsequent etching process is facilitated.

[0096] In other embodiments, after the step of forming the second doped conductive layer 104 and the third doped conductive layer 105, the step of removing the first glass layer 200 and the second glass layer 201 may further be included, in which a second transition region 180 and a texture region 190 are formed in the spacing region.

[0097] As shown in Figure 1, a passivation layer 106, a first electrode 108, and a second electrode 109 are formed.

[0098] The passivation layer 106 may be formed directly by total deposition. As can be understood, since the first portion 115 of the third doped conductive layer 105 is located on the sidewall of the first doped conductive layer 102, when forming the passivation layer 106, the sidewall of the first projection 130 located below the first portion 115 is shielded, and the thickness of the formed passivation layer 106 becomes thinner the closer it is to the first portion 115.

[0099] In other embodiments, when forming a first protrusion 130 and a second protrusion 140 of different heights, the formed first protrusion 130 becomes trapezoidal due to the crystal orientation of the substrate 100. In this way, during the formation of the passivation layer 106, the formation space becomes smaller the closer it is to the third doped conductive layer 105, affecting the formation rate of the passivation layer 106. As a result, in the direction from the first protrusion 130 towards the recess 150, the thickness of the passivation layer 106 located on the side wall of the first protrusion 130 gradually increases.

[0100] In other embodiments, a first electrode 108 electrically connected to the first doped conductive layer 102 and a second electrode 109 electrically connected to the second doped conductive layer 104 may be formed by screen printing.

[0101] Another embodiment of the present disclosure further provides a solar cell module which may include solar cells formed by the solar cell formation methods of some or all of the above embodiments, or by the solar cell formation methods of some or all of the above embodiments. Since the same or corresponding parts of the above embodiments can be referenced, further explanation is omitted below.

[0102] Figure 7 is a partial perspective view of a solar cell module according to another embodiment of the present disclosure, and Figure 8 is a schematic partial cross-sectional view along the first cross-sectional direction AA1 in Figure 7, as shown in Figures 7 and 8, In other embodiments, the solar cell module includes a plurality of solar cells 40 formed in some or all of the embodiments or by the method for forming the solar cells, and a battery string including a welded ribbon 43 that is electrically connected to at least two solar cells 40 and connects adjacent solar cells 40 in series.

[0103] The solar cell module further includes a sealing adhesive film 41 that covers the surface of the battery string.

[0104] The solar cell module further includes a cover plate 42 that covers the surface of the sealing adhesive film 41 that is separated from the battery string.

[0105] In other embodiments, the sealing adhesive film 41 includes a first sealing layer and a second sealing layer, the first sealing layer covering one of the front and back surfaces of the solar cell, and the second sealing layer covering the other of the front and back surfaces of the solar cell. Specifically, at least one of the first and second sealing layers may be an organic sealing adhesive film such as a polyvinyl butyral (PVB) adhesive film, an ethylene-vinyl acetate copolymer (EVA) adhesive film, a polyethylene octene copolymer (POE) adhesive film, or a polyethylene terephthalate (PET) adhesive film, or at least one of the first and second sealing layers may be an adhesive film such as an EP adhesive film, an EPE adhesive film, or a PVP adhesive film. EP adhesive film refers to a co-extruded adhesive film consisting of a laminated EVA adhesive film and a POE adhesive film, EPE adhesive film refers to a co-extruded adhesive film consisting of a laminated EVA adhesive film, a POE adhesive film, and an EVA adhesive film, and PVP adhesive film refers to a co-extruded adhesive film consisting of a laminated POE adhesive film, an EVA adhesive film, and an EVA adhesive film. The method for manufacturing a co-extruded adhesive film may involve sequentially extruding one or more raw materials onto another manufactured adhesive film during the processing of the adhesive film, or adhering different types of manufactured adhesive films to each other.

[0106] In some cases, the first and second sealing layers have a boundary line before lamination, and after the solar cell module is formed following the lamination process, the concepts of the first and second sealing layers disappear, i.e., the first and second sealing layers form an integrated sealing adhesive film 41.

[0107] In other 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 sealing adhesive film 41 may be an uneven surface or a texture including a plurality of protrusions, thereby improving the utilization rate of incident light. The cover plate 42 includes a first cover plate and a second cover plate, the first cover plate facing away from the first sealing layer and the second cover plate facing away from the second sealing layer.

[0108] Those skilled in the art will understand that the above embodiments are specific examples of realizing the present disclosure, and that in actual application, various modifications can be made in form and detail without departing from the spirit and scope of the embodiments of the present disclosure. Since various modifications and alterations can be made without departing from the spirit and scope of the embodiments of the present disclosure, the scope of protection of the embodiments of the present disclosure should be limited to the scope defined in the claims.

Claims

1. A substrate including a front and a back facing each other, wherein the back surface is provided with alternately arranged first protrusions and second protrusions, and a recess located between the first protrusions and the second protrusions, The first tunnel layer covering the first protrusion, A first doped conductive layer covering the surface of the first tunnel layer, The second tunnel layer covering the second protrusion, A second doped conductive layer covering the surface of the second tunnel layer, A third doped conductive layer provided in the recess so as to be separate from the second doped conductive layer, comprising a first portion located on the side wall of the first doped conductive layer, a second portion located on the side wall of the recess, and a third portion extending from the end of the second portion in a direction away from the first protrusion, wherein the type of ions doped inside the third doped conductive layer is different from that of the first doped conductive layer. It includes at least a passivation layer covering the surfaces of the first doped conductive layer, the second doped conductive layer, and the third doped conductive layer, The thickness of the passivation layer covering the surface of the first portion is greater than the thickness of the passivation layer covering the surface of the second portion. The recess includes a mounting area, a transition area, and a texture area arranged in order from the first protrusion side to the second protrusion side. The mounting area is connected to one side of the transition area, The third doped conductive layer is placed on the aforementioned mounting region. The texture region is connected to the other side of the transition region, There is a difference in height between the aforementioned texture area and the previously described placement area. A solar cell characterized by the following features.

2. The ratio of the thickness of the passivation layer covering the surface of the first portion to the thickness of the passivation layer covering the surface of the second portion is 1 to 0.

2. The solar cell according to feature 1.

3. The thickness of the passivation layer covering the surface of the first portion is 70 nm to 180 nm, and the thickness of the passivation layer covering the surface of the second portion is 14 nm to 180 nm. The solar cell according to feature 1.

4. The orthographic projection of the first portion onto the surface of the substrate partially overlaps with the orthographic projection of the third portion onto the surface of the substrate. The solar cell according to feature 1.

5. In the direction from the first protrusion to the second protrusion, the length of the first portion is 0.2 μm to 3 μm. The solar cell according to feature 1.

6. The ratio of the thickness of the first doped conductive layer to the thickness of the third doped conductive layer is 0.5 to 2. The solar cell according to feature 1.

7. The present invention further includes a third tunnel layer located between the first doped conductive layer and the third doped conductive layer, and between the third doped conductive layer and the substrate. The solar cell according to feature 1.

8. In the direction from the first protrusion toward the recess, the thickness of the passivation layer located on the surface of the second portion gradually increases. The solar cell according to feature 1.

9. The step of providing a substrate including a front and a back facing each other, wherein the back is provided with alternately arranged first protrusions and second protrusions, and a recess located between the first protrusions and the second protrusions, The steps include forming a first tunnel layer that covers the first protrusion, A step of forming a first doped conductive layer that covers the surface of the first tunnel layer, further forming a first glass layer that covers the surface of the first doped conductive layer and protrudes from the side wall of the first doped conductive layer, The steps include forming a second tunnel layer that covers the second protrusion, The steps include forming a second doped conductive layer that covers the surface of the second tunnel layer, The steps of forming a third doped conductive layer, which includes a first portion located on the side wall of the first doped conductive layer and covering the surface of the first glass layer toward the substrate, a second portion located on the side wall of the recess, and a third portion extending from the end of the second portion toward a direction away from the first protrusion, wherein the type of ions doped inside is different from that of the first doped conductive layer, The step of removing the first glass layer, The process includes the step of forming a passivation layer that covers the surfaces of the first doped conductive layer, the second doped conductive layer, and the third doped conductive layer, The thickness of the passivation layer covering the surface of the first portion is greater than the thickness of the passivation layer covering the surface of the second portion. A method for manufacturing solar cells, characterized by the following features.

10. The step of forming the third doped conductive layer is: The steps include forming an initial second doped conductive layer that covers the surface of the second tunnel layer, covers the surface of the first glass layer, and further covers the surfaces of the second protrusion and the recess, The process includes the steps of etching the initial second doped conductive layer to remove the initial second doped conductive layer located on the top surface of the first glass layer and a portion of the initial second doped conductive layer located on the surface of the recess, making the remaining initial second doped conductive layer located on the second protrusion the second doped conductive layer, and making the initial second doped conductive layer located on the recess and the first protrusion side the third doped conductive layer. The method for manufacturing a solar cell according to feature 9.

11. The step of forming the initial second doped conductive layer further includes the step of forming a second glass layer that covers the top surface of the initial second doped conductive layer, The step of etching the initial second doped conductive layer is: The steps include performing a laser process that irradiates the second glass layer located in the first protrusion and a portion of the second glass layer located in the recess, The process includes the step of performing an etching process to etch the second glass layer and the initial second doped conductive layer irradiated by the laser process to form the second doped conductive layer and the third doped conductive layer, A method for manufacturing a solar cell according to feature 10.

12. A battery string comprising a plurality of solar cells according to any one of claims 1 to 8 and a welded ribbon electrically connected to at least two of the solar cells and connecting adjacent solar cells in series, A sealing adhesive film covering the surface of the battery string, The sealing adhesive film includes a cover plate that covers the surface of the sealing adhesive film that is separated from the battery string, A solar cell module characterized by the following features.

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