Solar cell and method of manufacturing the same, photovoltaic module

Abstract

The embodiment of the present disclosure relates to the field of photovoltaics, and provides a solar cell and a manufacturing method thereof, and a photovoltaic module, wherein the solar cell comprises: a substrate; a doped conductive layer located in or on a surface of the substrate; a passivation layer located on a surface of the doped conductive layer; a plurality of first sub-electrodes, each of which at least partially penetrates the passivation layer and is in contact with the doped conductive layer, and the first sub-electrodes are arranged at intervals along a first direction and a second direction; and a plurality of second sub-electrodes, each of which extends along the second direction and is in contact connection with the plurality of first sub-electrodes arranged along the second direction, and each of the second sub-electrodes comprises: first metal particles, at least part of which are in electrical contact with the first sub-electrodes; and second metal particles, at least part of which are in electrical contact with the first sub-electrodes, and the material of the first metal particles is different from that of the second metal particles, and the first sub-electrodes and the second sub-electrodes constitute a first electrode. The damage to the tunneling layer can be reduced, and the efficiency of the solar cell can be improved.

Description

Technical Field

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

[0002] Photovoltaic power generation refers to the conversion of solar energy into electrical energy through the photovoltaic effect of semiconductors. For example, TOPCON (Tunnel Oxide Passivated Contact) cells have received increasing attention due to their better photoelectric conversion performance.

[0003] TOPCON cells are a type of tunneling oxide passivated contact solar cell technology based on the selective carrier principle. TOPCON cells have electrodes, and currently, the electrodes that penetrate the passivation layer are typically formed using a laser irradiation process. However, this method can cause significant damage to the passivation layer.

[0004] It is necessary to provide a new structure for solar cells that reduces damage to the passivation layer. Summary of the Invention

[0005] This disclosure provides a solar cell and a method for manufacturing the same, as well as a photovoltaic module, which can at least reduce damage to the passivation layer.

[0006] According to some embodiments of this disclosure, one aspect of this disclosure provides a solar cell, comprising: a substrate; a doped conductive layer located within or on the surface of the substrate; a passivation layer located on the surface of the doped conductive layer; a plurality of first sub-electrodes, each first sub-electrode at least partially penetrating the passivation layer and contacting the doped conductive layer, the first sub-electrodes being spaced apart along a first direction and a second direction; and a plurality of second sub-electrodes, each second sub-electrode extending along the second direction and contacting and connecting with the plurality of first sub-electrodes arranged along the second direction, the second sub-electrodes comprising: a first metal particle, at least a portion of the first metal particle being in electrical contact with the first sub-electrode, and a second metal particle, at least a portion of the second metal particle being in electrical contact with the first sub-electrode, the material of the first metal particle being different from the material of the second metal particle, the first sub-electrode and the second sub-electrode constituting a first electrode.

[0007] In some embodiments, the second sub-electrode is located on the surface of the passivation layer, and the second sub-electrode is in contact with at least one side of the first sub-electrode that protrudes from the passivation layer and is opposite to it along the second direction.

[0008] In some embodiments, the second sub-electrode also contacts the side of the first sub-electrode that protrudes from the passivation layer and is opposite to it along the first direction.

[0009] In some embodiments, the second sub-electrode further covers the top surface of the first sub-electrode.

[0010] In some embodiments, in the second direction, the ratio of the length of the second sub-electrode to the length of all the first sub-electrodes in contact with the second sub-electrode is 4:3 to 10:1.

[0011] In some embodiments, the number of second sub-electrodes is multiple, and the multiple second sub-electrodes are arranged at intervals, with the spacing between two adjacent second sub-electrodes being greater than the width of the second sub-electrodes in the first direction.

[0012] In some embodiments, in the second direction, the ratio of the area of ​​the second sub-electrode projected onto the substrate surface to the area of ​​all the first sub-electrodes in contact with the second sub-electrode projected onto the substrate surface is 4:3 to 100:1.

[0013] In some embodiments, the orthographic projection of the first sub-electrode on the substrate surface lies within the orthographic projection of the second sub-electrode on the substrate surface.

[0014] In some embodiments, in the first direction, the width of the first sub-electrode is greater than the width of the second sub-electrode.

[0015] In some embodiments, the first sub-electrode includes: a third metal particle in contact with the doped conductive layer; a glass layer located on the surface of the doped conductive layer and covering the surface of the third metal particle; and an electrode body located on the surface of the glass layer and in contact with the third metal particle.

[0016] In some embodiments, the material of the third metal particle is the same as that of the first metal particle.

[0017] In some embodiments, the diameter of the third metal particle is 10–20 nm.

[0018] In some embodiments, the first metal particle is a silver particle, and the second metal particle is a silver-coated copper particle.

[0019] In some embodiments, the substrate further includes a tunneling layer located on the surface of the substrate, and the doped conductive layer located on the surface of the tunneling layer.

[0020] According to some embodiments of this disclosure, another aspect of this disclosure provides a method for fabricating a solar cell, comprising: providing a substrate; forming a doped conductive layer located within or on the surface of the substrate; forming a passivation layer located on the surface of the doped conductive layer; forming a plurality of first sub-electrodes, each first sub-electrode at least partially penetrating the passivation layer and contacting the doped conductive layer, the first sub-electrodes being spaced apart along a first direction and a second direction; forming a plurality of second sub-electrodes, each second sub-electrode extending along the second direction and contacting and connecting with the plurality of first sub-electrodes arranged along the second direction, the second sub-electrode comprising: a first metal particle, at least a portion of the first metal particle being in electrical contact with the first sub-electrode, and a second metal particle, at least a portion of the second metal particle being in electrical contact with the first sub-electrode, the material of the first metal particle being different from the material of the second metal particle, the first sub-electrode and the second sub-electrode constituting a first electrode.

[0021] In some embodiments, the method of forming a plurality of first sub-electrodes includes: performing a first printing process to print a burn-through paste to form an initial first sub-electrode; and performing a high-temperature sintering process to convert the initial first sub-electrode into the first sub-electrode.

[0022] In some embodiments, the method for forming a plurality of second sub-electrodes includes: performing a second printing process to print a non-burn-through paste to form an initial second sub-electrode; and performing a drying process to convert the initial second sub-electrode into a second sub-electrode, wherein the process temperature of the high-temperature sintering process is greater than the process temperature of the drying process.

[0023] In some embodiments, the process further includes a contact enhancement process after the drying process. The contact enhancement process includes laser irradiation of the portion of the first sub-electrode in contact with the doped conductive layer and an external electric field applied to the second sub-electrode to form a contact structure on the contact surface between the first sub-electrode and the doped conductive layer.

[0024] In some embodiments, the process parameters of the contact enhancement process include: the wavelength of the laser is 632-1550 nm, and the laser is a monochromatic laser or a mixed laser.

[0025] According to some embodiments of this disclosure, another aspect of this disclosure also provides a photovoltaic module, a battery string, which is formed by connecting solar cells as described in any of the above claims, or by connecting solar cells manufactured by the manufacturing method of solar cells as described in any of the above claims; an encapsulation layer for covering the surface of the battery string; and a cover plate for covering the surface of the encapsulation layer opposite to the battery string.

[0026] The technical solution provided in this disclosure has at least the following advantages: The first and second sub-electrodes together constitute the electrodes of the solar cell. The first sub-electrodes, penetrating the passivation layer, are arranged at intervals along a first and second direction. The second sub-electrodes are in contact with the multiple first sub-electrodes arranged in the second direction. The first and second sub-electrodes can draw out the charge carriers inside the solar cell. Furthermore, the second sub-electrodes do not penetrate the passivation layer; that is, the first electrode, composed of the first and second sub-electrodes, only partially penetrates the passivation layer. This reduces the damaged area of ​​the passivation layer, decreases the proportion of the metal contact area, reduces metal contact recombination, and increases the open-circuit voltage, thereby ensuring the normal performance of the solar cell while improving its reliability. Secondly, by setting the second sub-electrode to be composed of first and second metal particles, with the materials of the first and second metal particles being different, the cost of the solar cell can be controlled by controlling the materials of the first and second metal particles. Moreover, at least some of the first and second metal particles are in electrical contact with the first sub-electrode, which does not affect the conductivity of the second sub-electrode. Attached Figure Description

[0027] 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.

[0028] Figure 1 This is a three-dimensional structural schematic diagram of a solar cell provided in an embodiment of the present disclosure;

[0029] Figure 2 A top view of a solar cell provided in an embodiment of this disclosure;

[0030] Figure 3 A cross-sectional view of a solar cell provided in an embodiment of this disclosure;

[0031] Figure 4 Another top view of a solar cell provided in an embodiment of this disclosure;

[0032] Figure 5 Another top view of a solar cell provided in an embodiment of this disclosure;

[0033] Figure 6Another top view of a solar cell provided in an embodiment of this disclosure;

[0034] Figure 7 A further top view of a solar cell provided in an embodiment of this disclosure;

[0035] Figure 8 A flowchart illustrating a method for manufacturing a solar cell according to an embodiment of this disclosure;

[0036] Figures 9 to 12 This is a schematic diagram of the structure corresponding to each step of the method for manufacturing a solar cell according to an embodiment of the present disclosure;

[0037] Figure 13 This is a schematic diagram of the structure of a photovoltaic module provided in one embodiment of the present disclosure;

[0038] Figure 14 This is a cross-sectional view of a photovoltaic module provided in one embodiment of the present disclosure. Detailed Implementation

[0039] As is known from the background technology, current electrodes usually penetrate the passivation layer directly. When forming an electrode that penetrates the passivation layer, it is inevitable to damage the passivation layer, which will increase the recombination of surface carriers and result in more metal contact sites, which will also increase metal contact recombination, thus making it difficult to further improve the open circuit voltage of the battery.

[0040] This disclosure provides a solar cell in which a first sub-electrode and a second sub-electrode together constitute the solar cell's electrode. The first sub-electrode, penetrating the passivation layer, is arranged at intervals along a first direction and a second direction. The second sub-electrode is in contact with the plurality of first sub-electrodes arranged in the second direction. The first and second sub-electrodes can draw out charge carriers from inside the solar cell. The second sub-electrode does not penetrate the passivation layer; that is, the first electrode, composed of the first and second sub-electrodes, only partially penetrates the passivation layer. This reduces the damaged area of ​​the passivation layer, decreases the proportion of the metal contact area, reduces metal contact recombination, and increases the open-circuit voltage, thereby ensuring the normal performance of the solar cell while improving its reliability. Furthermore, by setting the second sub-electrode to be composed of first and second metal particles, with the materials of the first and second metal particles being different, the cost of the solar cell can be controlled by adjusting the materials of the first and second metal particles. Since at least a portion of the first and second metal particles are in electrical contact with the first sub-electrode, the conductivity of the second sub-electrode is not affected.

[0041] As used herein, the terms “vertical,” “longitudinal,” “horizontal,” and “lateral” refer to the principal plane of the reference structure and are not necessarily defined by the Earth’s gravitational field. A “horizontal” or “lateral” direction is generally parallel to the principal plane of the structure, while a “vertical” or “longitudinal” direction is generally perpendicular to the principal plane of the structure. The principal plane of the structure is defined by the surface of the structure that has a relatively large area compared to the other surfaces of the structure. Referring to the figures, a “horizontal” or “lateral” direction may be perpendicular to the indicated “Z” axis and parallel to the indicated “X” axis and / or parallel to the indicated “Y” axis; and a “vertical” or “longitudinal” direction may be parallel to the indicated “Z” axis, perpendicular to the indicated “X” axis, and perpendicular to the indicated “Y” axis.

[0042] As used herein, features described as “adjacent” to each other (e.g., areas, structures, devices) mean and include features with one or more disclosed identifiers that are most closely (e.g., closest) to each other. Additional features (e.g., additional areas, additional structures, additional devices) with one or more disclosed identifiers that do not match “adjacent” features may be positioned between “adjacent” features. In other words, “adjacent” features may be positioned directly adjacent to each other such that no other features intervene between “adjacent” features; or “adjacent” features may be positioned indirectly adjacent to each other such that at least one feature having an identifier other than the identifier associated with at least one “adjacent” feature is positioned between “adjacent” features. Thus, features described as “vertically adjacent” to each other mean and include features disclosed by one or more identifiers located at the vertical closest (e.g., vertically closest) to each other. Furthermore, features described as “horizontally adjacent” to each other mean and include features of one or more disclosed identifiers located at the horizontal closest (e.g., horizontally closest) to each other.

[0043] In the following description, the second component may be formed or disposed above or on the first component, or on the surface of the first component, or on one side of the first component. This may include embodiments where the first and second components are in direct contact, and may also include embodiments where an additional component may be present between the first and second components, thereby preventing direct contact. For simplicity and clarity, various components may be drawn at different scales. In the accompanying drawings, some layers / components may be omitted for simplicity.

[0044] Unless otherwise specified, the formation or provision of a second component on the surface of a first component means that the first component and the second component are in direct contact.

[0045] The “components” mentioned above can refer to layers, films, regions, parts, structures, etc.

[0046] Furthermore, for ease of description, spaced relative terms such as “below,” “under,” “lower,” “above,” and “upper” may be used herein to describe the relationship of one element or component to another (or more) element or component as shown in the figures. In addition to the orientations shown in the figures, spaced relative terms are intended to include different orientations of the device during use or operation. The device may be oriented in other ways (rotated 90 degrees or in other orientations), and the spaced relative descriptors used herein can be interpreted accordingly. Additionally, the term “made of” may mean “comprising” or “consisting of.” Furthermore, one or more additional operations may occur during / between the described operations in subsequent manufacturing processes, and the order of operations may change. In the following embodiments, the terms “upper,” “above,” and / or “above” are defined along directions of increasing distance from the front and rear surfaces. Materials, configurations, dimensions, processes, and / or operations as described in the embodiments may be used in other embodiments, and their detailed descriptions may be omitted.

[0047] As used herein, spatial relative terms such as “below,” “under,” “lower,” “bottom,” “above,” “upper,” “top,” “front,” “back,” “left,” and “right” are used for ease of description to describe the relationship between one element or feature and another element or feature illustrated in the figures. Unless otherwise specified, spatial relative terms are intended to cover different orientations of material other than those depicted in the figures. For example, if the material in the figures is inverted, then an element described as “below,” “under,” “lower,” or “bottom” of another element or feature would be oriented “above” or “top” of said other element or feature. Thus, the term “below” may cover both above and below orientations depending on the context in which the term is used, as will be apparent to those skilled in the art. Material may be oriented in other ways (e.g., rotated 90 degrees, inverted, flipped), and the spatial relative descriptive terms used herein may be interpreted accordingly.

[0048] As used herein, unless the context clearly indicates otherwise, the singular forms “a / an” and “the” also implicitly include the plural forms.

[0049] As used in this article, “and / or” includes any and all combinations of one or more of the associated listed items.

[0050] As used in this article, the phrase “coupled to” refers to structures that are operatively connected to each other (e.g., by direct ohmic connection or by indirect connection (e.g., by means of another structure)).

[0051] As used herein, the terms "substantially" or "basically" with respect to a given parameter, property, or condition mean and include the degree to which a given parameter, property, or condition conforms to deviations (e.g., within acceptable tolerances) as would be understood by one of ordinary skill in the art. By way of example, depending on the specific parameter, property, or condition that is substantially satisfied, it may satisfy at least 90.0%, at least 95.0%, at least 99.0%, at least 99.9%, or even 100.0%.

[0052] As used herein, the terms "about," "approximately," or "about" when referring to a particular parameter include the value, and those skilled in the art will understand that the deviation from the value is within acceptable tolerances of the particular parameter. For example, "about" or "about" with respect to a value may include additional values ​​that are in the range of 90.0% to 110.0% of the value, such as in the range of 95.0% to 105.0%, 97.5% to 102.5%, 99.0% to 101.0%, 99.5% to 100.5%, or 99.9% to 100.1%.

[0053] As used herein, “conductive material” means and includes one or more of the following conductive materials: metals (e.g., tungsten (W), titanium (Ti), molybdenum (Mo), niobium (Nb), vanadium (V), hafnium (Hf), tantalum (Ta), chromium (Cr), zirconium (Zr), iron (Fe), ruthenium (Ru), osmium (Os), cobalt (Co), rhodium (Rh), iridium (Ir), nickel (Ni), palladium (Pa), platinum (Pt), copper (Cu), silver (Ag), gold (Au), aluminum (Al)), alloys (e.g., Co-based alloys, Fe-based alloys) The term "conductive structure" refers to and includes structures formed from and containing conductive materials, such as gold, Ni-based alloys, Fe and Ni-based alloys, Co and Ni-based alloys, Fe and Co-based alloys, Co, Ni and Fe-based alloys, Al-based alloys, Cu-based alloys, magnesium (Mg)-based alloys, Ti-based alloys, steel, low-carbon steel, and stainless steel. It also includes conductive metal materials (e.g., conductive metal nitrides, conductive metal silicides, conductive metal carbides, and conductive metal oxides) and conductive doped semiconductor materials (e.g., conductive doped polysilicon, conductive doped germanium (Ge), and conductive doped silicon-germanium (SiGe)). Furthermore, "conductive structure" means and includes structures formed from conductive materials and containing conductive materials.

[0054] As used herein, “insulating material” means and includes one or more of the following electrically insulating materials: at least one dielectric oxide material (e.g., one or more of silicon oxide (SiOx), phosphosilicate glass, borosilicate glass, borosilicate glass, fluorosilicate glass, aluminum oxide (AlOx), hafnium oxide (HfOx), niobium oxide (NbOx), titanium oxide (TiOx), zirconium oxide (ZrOx), tantalum oxide (TaOx), and magnesium oxide (MgOx); at least one dielectric nitride material (e.g., silicon nitride (SiNy)); at least one dielectric oxynitride material (e.g., silicon oxynitride (SiOxNy)); at least one dielectric carbon oxide material (e.g., silicon oxycarbonate (SiOxCy)); at least one hydrogenated dielectric carbon oxide material (e.g., hydrogenated silicon oxycarbonate (SiCxOyHz)); and at least one dielectric carbon oxynitride material (e.g., silicon oxycarbonate (SiOxCzNy)). The chemical formulas containing one or more of “x”, “y”, and “z” (e.g., SiOx, AlOx, HfOx, NbOx, TiOx, SiNy, SiOxNy, SiOxCy, SiCxOyHz, SiOxCzNy) in this document represent materials containing “x” atoms of one element, “y” atoms of another element, and “z” atoms of an additional element (if present) relative to each atom of another element (e.g., Si, Al, Hf, Nb, Ti). Because chemical formulas represent relative atomic ratios rather than strict chemical structures, insulating materials may include one or more stoichiometric compounds and / or one or more non-stoichiometric compounds, and the values ​​of “x”, “y”, and “z” (if present) may be integers or non-integers. As used herein, the term “non-stoichiometric compound” means and includes compounds composed of an element that cannot be expressed by a ratio of well-defined natural numbers and violates the law of definite proportions. Additionally, “insulating structure” means and includes structures formed of and containing insulating materials.

[0055] Unless the context otherwise indicates, the materials described herein can be formed by any suitable technique, including but not limited to spin coating, blanket coating, chemical vapor deposition (CVD), plasma-enhanced CVD (PECVD), atomic layer deposition (ALD), plasma-enhanced ALD (PEALD), physical vapor deposition (PVD) (e.g., sputtering), or epitaxial growth. Depending on the specific material to be formed, the technique used for depositing or growing the material can be selected by one of ordinary skill in the art. Additionally, unless the context otherwise indicates, the removal of the material described herein can be achieved by any suitable technique, including but not limited to etching (e.g., dry etching, wet etching, vapor phase etching), ion milling, planarization (e.g., chemical mechanical planarization (CMP)), or other known methods.

[0056] As used herein, the term "semiconductor" can refer to, for example, a material layer, substrate, wafer, or substructure, and includes any substrate semiconductor structure. "Semiconductor" should be understood to include silicon sapphire (SOS) technology, silicon-on-insulator (SOI) technology, thin-film transistor (TFT) technology, doped and undoped semiconductors, epitaxial silicon layers supported by a substrate semiconductor structure, and other semiconductor structures well known to those skilled in the art. Furthermore, when "semiconductor" is referred to in the following description, regions / junctions may have been formed in the substrate semiconductor structure using prior process steps, and the term "semiconductor" may include an underlying layer containing such regions / junctions.

[0057] Unless the context clearly indicates otherwise, the term "conductive" and its related forms, such as conduct, conducting, and conduction, conductively, and conductivity, as used herein refer to electrical conductivity. Similarly, unless the context clearly indicates otherwise, the term "connection" and its related forms, such as connect, connected, and connection, as used herein refer to electrical connection.

[0058] 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.

[0059] refer to Figures 1 to 3 ,in, Figure 1 This is a three-dimensional structural schematic diagram of a solar cell provided in an embodiment of the present disclosure; Figure 2 This is a top view of a solar cell provided in an embodiment of the present disclosure. Figure 3 A solar cell provided in an embodiment of this disclosure Figure 2 A cross-sectional view along the AA1 direction.

[0060] In some embodiments, a solar cell may include a substrate 100.

[0061] The solar cell may also include a doped conductive layer 101, which is located within or on the surface of the substrate 100.

[0062] The solar cell may also include a passivation layer 102, which is located on the surface of the doped conductive layer 101.

[0063] The solar cell may further include: a plurality of first sub-electrodes 103, each first sub-electrode 103 at least partially penetrating the passivation layer 102 and contacting the doped conductive layer 101, the first sub-electrodes 103 being arranged at intervals along a first direction X and a second direction Y.

[0064] The solar cell may further include: a plurality of second sub-electrodes 104, each second sub-electrode 104 extending along a second direction Y and in contact with a plurality of first sub-electrodes 103 arranged along the second direction Y. The second sub-electrode 104 includes: a first metal particle 114, at least a portion of the first metal particle 114 being in electrical contact with the first sub-electrode 103, and a second metal particle 124, at least a portion of the second metal particle 124 being in electrical contact with the first sub-electrode 103. The material of the first metal particle 114 is different from the material of the second metal particle 124. The first sub-electrode 103 and the second sub-electrode 104 constitute a first electrode.

[0065] In this embodiment, the electrodes of the solar cell are formed by a first sub-electrode 103 and a second sub-electrode 104. The first sub-electrode 103, which penetrates the passivation layer 102, is arranged at intervals along the first direction X and the second direction Y. The second sub-electrode 104 is in contact with the multiple first sub-electrodes 103 arranged in the second direction Y. The first sub-electrode 103 and the second sub-electrode 104 can draw out the charge carriers inside the solar cell. The second sub-electrode 104 does not penetrate the passivation layer 102. That is to say, the first electrode formed by the first sub-electrode 103 and the second sub-electrode 104 only partially penetrates the passivation layer 102, thereby reducing the damaged area of ​​the passivation layer 102, reducing the proportion of the metal contact area, reducing metal contact recombination, and increasing the open circuit voltage. This ensures the normal performance of the solar cell while improving its reliability. Secondly, by setting the second sub-electrode 104 to be composed of the first metal particle 114 and the second metal particle 124, and the material of the first metal particle 114 is different from that of the second metal particle 124, the cost of the solar cell can be controlled by controlling the materials of the first metal particle 114 and the second metal particle 124. Moreover, at least some of the first metal particle 114 and at least some of the second metal particle 124 are in electrical contact with the first sub-electrode 103, which will not affect the conductivity of the second sub-electrode 104.

[0066] In some embodiments, the substrate provided in this application can be a silicon substrate, specifically an N-type or P-type monocrystalline silicon substrate or a polycrystalline silicon substrate. The solar cell can be an emitter and back passivated cell (PERC), a tunnel oxide passivated contact cell (TOPCon), an interdigitated back contact cell (IBC), or a stacked cell, etc. These are just examples and are not specifically limited.

[0067] The substrate 100 is used to receive incident light and generate photogenerated carriers. In some embodiments, the substrate 100 may be a semiconductor substrate, such as silicon, germanium, germanium-silicon, or silicon on an insulator.

[0068] In some 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 monocrystalline, polycrystalline, amorphous, or microcrystalline (a state simultaneously possessing both monocrystalline and amorphous states is called microcrystalline). For example, silicon may be at least one of monocrystalline silicon, polycrystalline silicon, amorphous silicon, or microcrystalline silicon. If the material of the substrate 100 is silicon, then the material of the substrate 100 may include at least one of monocrystalline silicon, polycrystalline silicon, amorphous silicon, or microcrystalline silicon.

[0069] In some embodiments, the substrate 100 may also be a compound semiconductor material. Common compound semiconductor materials include, but are not limited to, silicon germanide, silicon carbide, gallium arsenide, indium gallium arsenide, perovskite, cadmium telluride, copper indium selenide, etc. Materials may also be silicon carbide, organic materials, or multi-component compounds. Multi-component compounds may include, but are not limited to, perovskite, gallium arsenide, cadmium telluride, copper indium selenide, etc.

[0070] The substrate 100 can also be a sapphire substrate 100, a silicon substrate on an insulator, or a germanium substrate on an insulator.

[0071] 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 any one of group V elements such as phosphorus (P), bismuth (Bi), antimony (Sb), or arsenic (As). The P-type semiconductor substrate 100 is doped with a P-type dopant element, which can be any one of group III elements such as boron (B), aluminum (Al), gallium (Ga), or indium (In).

[0072] The substrate 100 may include a front side and a back side. If the solar cell is a single-sided cell, the front side serves as the light-receiving surface to receive incident light. If the solar cell is a double-sided cell, both the front side and the back side serve as light-receiving surfaces.

[0073] In some embodiments, the surface of the substrate 100 may also have a textured structure, which may include a regular pyramidal textured structure or an irregularly shaped black silicon. The beveled surface of the textured structure can increase the internal reflection of incident light, thereby improving the absorption and utilization rate of incident light by the substrate 100, and thus improving the cell efficiency of the solar cell.

[0074] In some embodiments, the doping elements in the doped conductive layer 101 are different from those in the substrate 100. In this case, the doped conductive layer 101 is located on the front side of the solar cell and serves as the emitter 111. In some embodiments, the doping elements in the doped conductive layer 101 are the same as those in the substrate 100. In this case, the doped conductive layer 101 is located on the back side of the solar cell and serves as the doped polycrystalline silicon layer 121 on the back side.

[0075] For example, if the element doped in the substrate 100 is an N-type dopant, and the element doped in the conductive layer 101 is a P-type dopant, then the conductive layer 101 serves as the emitter 111 on the front side of the solar cell. If the element doped in the conductive layer 101 is an N-type dopant, then the conductive layer 101 serves as the doped polycrystalline silicon layer 121 on the back side of the solar cell.

[0076] In some embodiments, the solar cell may further include: a tunneling layer 105 located on the surface of the substrate 100, and a doped conductive layer 101 located on the surface of the tunneling layer 105. By providing the tunneling layer 105, the tunneling layer 105 and the doped conductive layer 101 together constitute the passivation contact structure of the solar cell, thereby forming band bending on the substrate surface and achieving selective transport of charge carriers.

[0077] In some embodiments, the dopant concentration in the doped conductive layer 101 is greater than that in the substrate 100, to form a sufficiently high potential barrier on the substrate surface. This barrier can induce band bending on the substrate surface, enabling the aggregation of majority carriers and the depletion of minority carriers, thereby reducing carrier recombination. The tunneling layer 105 can cause an asymmetric shift in the energy bands on the substrate 100 surface, making the barrier for majority carriers lower than that for minority carriers. Therefore, majority carriers can more easily tunnel through the tunneling layer 105 to the doped conductive layer 101, while minority carriers have difficulty passing through the tunneling layer 105, achieving selective carrier transport. Furthermore, the tunneling layer 105 also provides chemical passivation. Specifically, due to the presence of interface state defects at the interface between the substrate 100 and the tunneling layer 105, the interface state density on the back side of the substrate 100 is relatively large. The increase in interface state density will promote the recombination of photogenerated carriers, reduce the fill factor, short-circuit current and open-circuit voltage of the solar cell, and thus result in a lower photoelectric conversion efficiency of the solar cell.

[0078] The tunneling layer 105 is located on the back side of the substrate 100, so that the tunneling layer 105 has a chemical passivation effect on the surface of the substrate 100. Specifically, by saturating the dangling bonds on the surface of the substrate 100, the defect state density on the surface of the substrate 100 is reduced, and the recombination centers on the surface of the substrate 100 are reduced, thereby reducing the carrier recombination rate.

[0079] In some embodiments, the material of the tunneling layer 105 may include at least one of silicon oxide, silicon nitride, silicon oxynitride, silicon carbide, or magnesium fluoride.

[0080] The doped conductive layer 101 also serves as a field passivation effect. Specifically, the doped conductive layer 101 forms an electrostatic field pointing towards the interior of the substrate 100 on the back side of the substrate 100, causing minority carriers to escape from the interface, thereby reducing the minority carrier concentration and decreasing the carrier recombination rate at the interface of the substrate 100. This, in turn, increases the open-circuit voltage, short-circuit current, and fill factor of the solar cell, thereby improving the photoelectric conversion efficiency of the solar cell.

[0081] The material of the doped conductive layer 101 may include at least one of amorphous silicon, polycrystalline silicon, or silicon carbide.

[0082] Therefore, the passivation contact structure formed by the doped conductive layer 101 and the tunneling layer 105 provides good surface passivation for the substrate surface. The tunneling layer 105 allows majority carriers to tunnel into the doped conductive layer 101 while blocking minority carrier recombination, so that majority carriers are laterally transported in the doped conductive layer 101 and collected by the metal electrode, thereby greatly reducing the metal contact recombination current and improving the open-circuit voltage and short-circuit current of the solar cell.

[0083] In some embodiments, the passivation layer 102 can effectively passivate the surface of the substrate 100, reduce the defect state density on the surface of the substrate 100, and better suppress carrier recombination on the surface of the substrate 100. The passivation layer 102 can also effectively reduce reflection, decrease the reflection of incident light on the surface of the substrate 100, and improve the utilization rate of incident light by the substrate 100.

[0084] The material of the passivation layer 102 can be one of silicon oxide, aluminum oxide, silicon nitride, or silicon oxynitride.

[0085] The passivation layer 102 can be a single-layer structure or a multi-layer structure. In the case of a multi-layer structure, the materials of different layers can be different from each other, or some layers can be made of the same material but different from the materials of other layers. For example, the passivation layer 102 can be a multi-layer structure of silicon nitride and aluminum oxide layers.

[0086] In some embodiments, the passivation layer 102 has a multi-layer structure, and the thickness of different layers can also be different. The thickness of different layers can be selected according to actual needs.

[0087] In some embodiments, the thickness of the passivation layer 102 can be 50nm to 150nm, such as 75nm, 85nm, 93nm, 116nm, 129nm, or 142nm, etc. It is understood that if the passivation layer 102 is too thin, the passivation effect will be poor; if the passivation layer 102 is too thick, it will lead to excessive light absorption, affecting the short-wavelength response. Therefore, setting the thickness of the passivation layer 102 to 50nm can achieve a certain passivation effect while avoiding affecting the performance of the solar cell.

[0088] It is understandable that if the doped conductive layer 101 is located on the front side of the substrate 100, the passivation layer 102 serves as the front passivation and antireflection layer, covering the surface of the doped conductive layer; if the doped conductive layer 101 is located on the back side of the substrate 100, the passivation layer 102 serves as the back passivation and antireflection layer.

[0089] In some embodiments, the first sub-electrode 103 may be arranged in an array along the first direction X and the second direction Y. The array arrangement of the first sub-electrode 103 facilitates the production of the printing screen, thereby reducing the process difficulty of forming the first sub-electrode 103. Moreover, the array arrangement of the first sub-electrode 103 also helps to improve the aesthetics of the solar cell.

[0090] In some embodiments, each first sub-electrode 103 at least partially penetrates the passivation layer 102 may mean that, for any one first sub-electrode 103, a portion of the first sub-electrode 103 completely penetrates the passivation layer 102, or a portion of the first sub-electrode 103 is embedded within the passivation layer 102; or it may mean that the first sub-electrode 103 completely penetrates the passivation layer 102.

[0091] It should be noted that: a portion of the first sub-electrode 103 can completely penetrate the passivation layer 102, while a portion of the first sub-electrode 103 can be embedded in the passivation layer 102. This means that when the first sub-electrode 103 is formed, a portion of the first sub-electrode 103 is thicker and a portion is thinner. The thicker portion penetrates the passivation layer 102 and contacts the doped conductive layer 101, while the thinner portion is embedded in the passivation layer 102 and spaced apart from the doped conductive layer 101.

[0092] In some embodiments, the first sub-electrode 103 penetrating the passivation layer 102 may also be embedded within the doped conductive layer 101. In other words, the distance between the surface of the first sub-electrode 103 facing the substrate 100 and the surface of the substrate 100 is less than the distance between the surface of the doped conductive layer 101 away from the substrate 100 and the surface of the substrate 100. In some embodiments, the surface of the first sub-electrode 103 penetrating the passivation layer 102 may also contact the surface of the doped conductive layer 101. In other words, the first sub-electrode 103 covers the surface of the doped conductive layer but is not embedded within the doped conductive layer 101.

[0093] In some embodiments, the top surface of the first sub-electrode 103 is higher than the top surface of the passivation layer 102, that is, the first sub-electrode 103 protrudes from the surface of the passivation layer 102.

[0094] In some embodiments, the top surface of the first sub-electrode 103 is flush with the top surface of the passivation layer 102, that is, the first sub-electrode 103 is surrounded by the passivation layer 102.

[0095] Continue to refer to Figures 1 to 3In some embodiments, the first sub-electrode 103 includes: a third metal particle 113 in contact with the doped conductive layer 101; a glass layer 123 located on the surface of the doped conductive layer 101 and covering the surface of the third metal particle 113; and an electrode body 133 located on the surface of the glass layer 123 and in contact with the third metal particle 113. The third metal particle 113 is located inside the glass layer 123 and in contact with the doped conductive layer 101, thereby achieving contact electrical connection between the first sub-electrode 103 and the doped conductive layer 101. The glass layer 123 is located between the electrode body 133 and the doped conductive layer 101 and is formed by the reaction of the material in the paste used to print the first sub-electrode 103 with the passivation layer 102 during the formation of the first sub-electrode 103. The electrode body 133 is the main part of the first sub-electrode 103 that transports charge carriers, and the electrode body 133 is in contact with the second sub-electrode 104 and collects charge carriers into the second sub-electrode 104.

[0096] In some embodiments, the material of the third metal particle 113 is the same as that of the first metal particle 114. By setting the material of the third metal particle 113 to be the same as that of the first metal particle 114, the lattice difference between the first metal particle 114 and the first sub-electrode 103 can be reduced, thereby improving the reliability of the contact between the first metal particle 114 and the first sub-electrode 103.

[0097] In some embodiments, the material of the third metal particle 113 may be silver particles. During the formation of the first sub-electrode 103, the glass powder in the slurry is fused with the passivation layer 102 through a high-temperature sintering process to form a glass layer 123. The silver particles precipitated in the slurry are distributed inside the glass layer 123 and at the interface between the glass layer 123 and the doped conductive layer 101, forming a metal-semiconductor contact with the doped conductive layer 101.

[0098] In some embodiments, the diameter of the third metal particle 113 is 10–20 nm, for example, 11 nm, 12.3 nm, 15.4 nm, 18.9 nm, or 19.7 nm, etc. By controlling the diameter of the third metal particle 113 to be 10–20 nm, it is easier for the third metal particle 113 to be deposited, and the contact effect between the third metal particle 113 and the doped conductive layer 101 can be increased.

[0099] In some embodiments, the thickness of the glass layer 123 is 10–500 nm, for example, 50 nm, 78 nm, 146 nm, 285 nm, 395 nm, or 471 nm, etc. By setting the thickness of the glass layer 123 to 10–500 nm, on the one hand, the glass layer 123 is not too thick, which facilitates the contact between the third metal particle 113 and the electrode body 133; on the other hand, the glass layer 123 is not too thin, which allows for control of the paste usage, so that the first sub-electrode 103 has a certain thickness as a whole, thereby improving the reliability of the first sub-electrode 103.

[0100] In some embodiments, the material of the glass layer 123 may include one or more compounds such as silicon oxide, silicon nitride, silicon oxynitride, silicates, lead oxide, aluminum oxide, and boric acid.

[0101] In some embodiments, a portion of the electrode body 133 is in contact with the passivation layer 102, and a portion of the electrode body 133 protrudes from the surface of the passivation layer 102. By setting a portion of the electrode body 133 in contact with the passivation layer 102 and a portion of the electrode body 133 protruding from the surface of the passivation layer 102, electrical contact between the first sub-electrode 103 and the second sub-electrode 104 can be facilitated.

[0102] In some embodiments, the width of the electrode body 133 in the first direction X is 5 to 50 μm, for example, 7 μm, 10 μm, 15 μm, 26 μm, 33 μm, or 47 μm, etc. For the electrode body 133, the larger the width of the electrode body 133, the greater the damage to the passivation layer 102; the smaller the width of the electrode body 133, the weaker the ability to collect charge carriers. Therefore, setting the width of the electrode body 133 to 5 to 50 μm reduces damage to the passivation layer 102 while increasing the ability of the first sub-electrode 103 to collect charge carriers.

[0103] In some embodiments, in the first direction X, the spacing between adjacent electrode bodies 133 is greater than or equal to the width of the electrode body 133. It is understood that the passivation layer 102 damaged after the formation of the first sub-electrode 103 includes not only the penetrated passivation layer but also a portion of the passivation layer 102 surrounding the first sub-electrode 103. Therefore, by setting the spacing between adjacent electrode bodies 133 to be greater than or equal to the width of the electrode body 133, damage to the same portion of the passivation layer 102 is avoided when different first sub-electrodes 103 are formed, further reducing damage to the passivation layer 102.

[0104] In some embodiments, the first metal particle 114 is a silver particle, and the second metal particle 124 is a silver-coated copper particle. The silver-coated copper particle contains copper particles inside and is coated with silver on the outside. By using silver particles for the first metal particle 114 and silver particles for the second metal particle 124, on the one hand, the use of silver can be reduced, lowering costs. Furthermore, silver-coated copper particles, compared to silver particles, also possess excellent conductivity and a certain degree of corrosion resistance. On the other hand, the silver particles ensure the conductivity of the second sub-electrode, thereby improving the carrier transport rate.

[0105] In some embodiments, the silver content to copper content of the second sub-electrode 104 material is less than 4:1. By controlling the silver content to copper content to be less than 4:1, the material cost of the second sub-electrode 104 can be further controlled.

[0106] In some embodiments, the width of the second sub-electrode 104 in the first direction X is 5–50 μm, for example, 8 μm, 13 μm, 19 μm, 26 μm, 34 μm, 41 μm, or 49 μm, etc. By controlling the width of the second sub-electrode 104 to be 5–50 μm, on the one hand, the second sub-electrode 104 is guaranteed to have a certain transmission rate, and on the other hand, the light-shielding area of ​​the second sub-electrode 104 on the surface of the substrate 100 is reduced.

[0107] Reference Figure 1 , Figure 2 , Figure 4 and Figure 5 ,in, Figure 4 Another top view of the solar cell provided in an embodiment of this disclosure. Figure 5 This is another top view of a solar cell provided in an embodiment of the present disclosure.

[0108] In some embodiments, the second sub-electrode 104 is located on the surface of the passivation layer 102, and the second sub-electrode 104 is in contact with at least one side of the first sub-electrode 103 that protrudes from the passivation layer 102 and is opposite to it along the second direction Y. By setting the second sub-electrode 104 to be in contact with at least one side of the first sub-electrode 103 that protrudes from the passivation layer 102 and is opposite to it along the second direction Y, on the one hand, multiple first sub-electrodes 103 arranged along the second direction Y can be connected by multiple second sub-electrodes 104, thereby facilitating the collection and transport of charge carriers; on the other hand, the slurry required to form the second sub-electrode 104 can be adjusted as needed, thereby controlling costs.

[0109] For the second sub-electrode 104, the second sub-electrode 104 can be located only between two first sub-electrodes 103 arranged along the second direction Y, and one second sub-electrode 104 is in contact with two adjacent first sub-electrodes 103. The second sub-electrode 104 can also have more lateral contact with the first sub-electrodes 103. For the option where the second sub-electrode 104 is located only between two first sub-electrodes 103 arranged along the second direction Y, it is understood that this option uses the least amount of paste, and the corresponding cost of the solar cell is the lowest. For the option where the second sub-electrode 104 can have more lateral contact with the first sub-electrodes 103, the larger the contact area between the second sub-electrode 104 and the first sub-electrode 103, the lower the contact resistance between the second sub-electrode 104 and the first sub-electrode 103, and the better the carrier transport performance of the solar cell.

[0110] refer to Figure 5 In some embodiments, the second sub-electrode 104 also contacts the side of the first sub-electrode 103 that protrudes from the passivation layer 102 and is opposite to it along the first direction X. Here, contact with the side of the first sub-electrode 103 opposite to it along the first direction X can mean contact with one of the two opposite sides, or it can mean contact with both opposite sides. By setting the second sub-electrode 104 to also contact the side of the first sub-electrode 103 that protrudes from the passivation layer 102 and is opposite to it along the first direction X, the second sub-electrode 104 connected to the first sub-electrodes 103 arranged along the second direction Y can be integrated into a single unit. That is, one second sub-electrode 104 is in contact with all the first sub-electrodes 103 arranged along the second direction Y, thereby improving the reliability of the second sub-electrode 104. Compared to the scheme where the second sub-electrode 104 only contacts the side of the first sub-electrode 103 that protrudes from the passivation layer 102 and is opposite to it along the second direction Y, this increases the contact area between the second sub-electrode 104 and the first sub-electrode 103, improving contact reliability, reducing contact resistance, and thus improving the performance of the solar cell.

[0111] In some embodiments, the second sub-electrode 104 may also contact only the side of the first sub-electrode 103 that protrudes from the passivation layer 102 and is opposite to it along the first direction X. However, for this solution, the manufacturing process is relatively complex, and the contact area is not much different from the contact area of ​​the second sub-electrode 104 that only contacts the side of the first sub-electrode 103 that is opposite to it along the second direction Y, so the efficiency improvement is limited. This is only described as an embodiment.

[0112] refer to Figure 2In some embodiments, the second sub-electrode 104 also covers the top surface of the first sub-electrode 103. The second sub-electrode 104 may only cover the top surface of the first sub-electrode 103, or the second sub-electrode 104 may cover the top surface of the first sub-electrode 103 and also contact the side of the first sub-electrode 103 that protrudes from the passivation layer 102 and is opposite to it along the second direction Y; or the second sub-electrode 104 may cover the top surface of the first sub-electrode 103 and also contact the side of the first sub-electrode 103 that protrudes from the passivation layer 102 and is opposite to it along the second direction Y, and the second sub-electrode 104 may also contact one or two side surfaces of the first sub-electrode 103 that protrude from the passivation layer 102 and are opposite to it along the first direction X. By setting the second sub-electrode 104 to also cover the top surface of the first sub-electrode 103, the contact area between the second sub-electrode 104 and the first sub-electrode 103 can be increased, thereby reducing contact resistance and increasing contact reliability.

[0113] It is understandable that the following schemes are defined as follows: Scheme 1: the second sub-electrode 104 contacts only the side of the first sub-electrode 103 that protrudes from the passivation layer 102 and is in contact with the side of the first sub-electrode 103 that protrudes from the passivation layer 102 and is in contact with the side of the first sub-electrode 103 that protrudes from the passivation layer 102 and is in contact with one or two sides of the first sub-electrode 103 that protrudes from the passivation layer 102 and is in contact with the side ...

[0114] Of the above three schemes, Scheme 3 has the most convenient formation process. Understandably, Scheme 3 only requires limiting the width of the second sub-electrode 104 in the first direction X, and the rest only requires controlling the amount of paste used. This allows control over the coverage of the second sub-electrode 104 on different surfaces of the first sub-electrode 103. However, Scheme 3 uses the most paste and has the best contact effect. Scheme 2 is more difficult to form than Scheme 3 because it requires limiting the width of the second sub-electrode 104 in the first direction X and controlling the amount of paste used to prevent it from covering the top surface of the first sub-electrode 103. However, Scheme 2 uses less paste than Scheme 3, and the contact effect is also good. Scheme 1 is the most difficult to form because it requires limiting both the width of the second sub-electrode 104 in the first direction X and the length of the second sub-electrode 104 in the second direction Y. However, Scheme 1 uses the least amount of paste.

[0115] In some embodiments, the second sub-electrode 104 may also cover the surface of the first sub-electrode 103 located within the passivation layer 102. In other words, the first sub-electrode 103 and the passivation layer 102 are further separated by the second sub-electrode 104. It is understood that, in order to form the first sub-electrode 103 in contact with the doped conductive layer 101, the first sub-electrode 103 is typically formed using a burn-through paste. During this process, the passivation layer 102 is damaged, and the material of the first sub-electrode 103 reacts with the passivation layer 102, further affecting the passivation effect. Therefore, the second sub-electrode 104 is configured to also cover the surface of the first sub-electrode 103 located within the passivation layer 102, thereby separating the first sub-electrode 103 from the passivation layer 102 and preventing further reaction between the first sub-electrode 103 and the passivation layer 102. This prevents the first sub-electrode 103 from further affecting the passivation effect of the passivation layer 102 and improves the performance of the solar cell.

[0116] In some embodiments, the second sub-electrode 104 covering the surface of the first sub-electrode 103 located within the passivation layer 102 can increase the contact surface between the first sub-electrode 103 and the second sub-electrode 104, thereby reducing the contact resistance and correspondingly reducing the size of the first sub-electrode 103, thereby further reducing the amount of slurry used.

[0117] In some embodiments, in the second direction Y, the ratio of the length of the second sub-electrode 104 to the length of all the first sub-electrodes 103 in contact with the second sub-electrode 104 is 4:3 to 10:1. It is understood that the length of the second sub-electrode 104 can actually be approximately equal to the length of all the first sub-electrodes 103 in contact with the second sub-electrode 104 plus the distance between the first sub-electrodes 103 (e.g., ...). Figure 2 or Figure 5 ), or the length of the second sub-electrode 104 is equal to the distance between two adjacent first sub-electrodes 103 (e.g. Figure 4 In other words, the ratio of the length of the second sub-electrode 104 to the length of all the first sub-electrodes 103 in contact with the second sub-electrode 104 is 4:3 to 10:1. This can also be equated to limiting the ratio between the length of the first sub-electrode 103 and the distance between the first sub-electrodes 103. By limiting the ratio between the length of the first sub-electrode 103 and the distance between the first sub-electrodes 103, it is possible to avoid the spacing between two adjacent first sub-electrodes 103 in the second direction Y being too short, thereby reducing the ability of the first sub-electrodes 103 to damage the passivation layer 102. Similarly, it is possible to avoid the spacing between two adjacent first sub-electrodes 103 in the second direction Y being too long, thereby affecting the ability of the first sub-electrodes 103 to collect charge carriers.

[0118] It is understandable that for the first sub-electrode 103, the longer the length of the first sub-electrode 103 and the denser the arrangement, the stronger the ability of the first sub-electrode 103 to collect charge carriers. Correspondingly, the first sub-electrode 103 will increase metal contact recombination, causing open circuit voltage loss. Moreover, the first sub-electrode 103 will increase the consumption of slurry and increase costs.

[0119] In some embodiments, there are multiple second sub-electrodes 104, and the multiple second sub-electrodes 104 are arranged at intervals, with the spacing between two adjacent second sub-electrodes 104 being greater than the width of the second sub-electrodes 104 in the first direction X. By controlling the spacing between two adjacent second sub-electrodes 104 to be greater than the width of the second sub-electrodes 104 in the first direction X, the light-shielding effect of the second sub-electrodes 104 on the substrate 100 is reduced. On the other hand, the amount of paste used for the second sub-electrodes 104 can also be reduced, thereby controlling the overall cost of the solar cell.

[0120] In some embodiments, in the second direction Y, the ratio of the area of ​​the second sub-electrode 104 projected onto the surface of the substrate 100 to the area of ​​all the first sub-electrodes 103 in contact with the second sub-electrode 104 projected onto the surface of the substrate 100 is 4:3 to 100:1. By controlling the ratio of the areas between the second sub-electrode 104 and the first sub-electrode 103, the contact area between the second sub-electrode 104 and the first sub-electrode 103, as well as the spacing between adjacent first sub-electrodes 103, is controlled. This avoids damage to the passivation layer 102 in the same area when different first sub-electrodes 103 are formed, and further reduces damage to the passivation layer 102.

[0121] Similarly, for the first sub-electrode 103, the larger the area of ​​the first sub-electrode 103 projected onto the surface of the substrate 100 and the denser its arrangement, the stronger the first sub-electrode 103's ability to collect charge carriers. Correspondingly, the first sub-electrode 103 will increase metal contact recombination, causing open circuit voltage loss. Moreover, the first sub-electrode 103 will also increase paste consumption and increase costs.

[0122] refer to Figure 2 In some embodiments, the orthographic projection of the first sub-electrode 103 onto the surface of the substrate 100 lies within the orthographic projection of the second sub-electrode 104 onto the surface of the substrate 100. In other words, the second sub-electrode 104 at least covers the first sub-electrode 103 protruding from the surface of the passivation layer 102, thereby increasing the contact area between the first sub-electrode 103 and the second sub-electrode 104, which can reduce the overall resistance of the first sub-electrode 103 and the second sub-electrode 104.

[0123] refer to Figure 6 , Figure 6 Another top view of a solar cell provided in an embodiment of this disclosure.

[0124] In some embodiments, in the first direction X, the width of the first sub-electrode 103 is greater than the width of the second sub-electrode 104. In other words, the second sub-electrode 104 covers part of the top surface of the first sub-electrode 103, but does not cover the entire top surface of the first sub-electrode 103. On the one hand, this reduces the amount of paste used in the second sub-electrode 104, and on the other hand, the light-shielding area of ​​the second sub-electrode 104 is smaller, thereby obtaining a higher short-circuit current.

[0125] refer to Figure 7 , Figure 7 This is yet another top view of a solar cell provided in an embodiment of the present disclosure.

[0126] In some embodiments, the orthographic projection of the first sub-electrode 103 onto the surface of the substrate 100 partially coincides with the orthographic projection of the second sub-electrode 104 onto the surface of the substrate 100. In other words, a portion of the second sub-electrode 104 covers the top surface of the first sub-electrode 103, and a portion of the second sub-electrode 104 covers the surface of the passivation layer 102.

[0127] In some embodiments, the first sub-electrode 103 and the second sub-electrode 104 are located on the front side, and the back side of the solar cell further includes an antireflection layer 106. The antireflection layer 106 can provide good passivation for the back side of the substrate 100, for example, it can effectively passivate the dangling bonds on the back side of the substrate 100, saturate the dangling bonds on the back side of the substrate 100, reduce the defect state density on the back side of the substrate 100, and suppress carrier recombination on the back side of the substrate 100.

[0128] The antireflection layer 106 can be made of one of silicon oxide, aluminum oxide, silicon nitride, or silicon oxynitride.

[0129] The antireflection layer 106 can be a single-layer structure or a multi-layer structure. For a multi-layer structure, the materials of different layers can be different from each other, or some layers can be made of the same material but different from the materials of other layers. For example, the antireflection layer 106 can be a multi-layer structure of silicon nitride and aluminum oxide layers.

[0130] In some embodiments, the solar cell further includes a back electrode 107, a plurality of back electrodes 107 being located on the surface of the antireflection layer 106, and the back electrode 107 also penetrating a portion of the antireflection layer 106 and a portion of the thickness of the doped polycrystalline silicon layer 121 to form an ohmic contact with the doped polycrystalline silicon layer 121.

[0131] The majority carriers in the substrate 100 tunnel through the tunneling layer 105 to the doped polysilicon layer 121. The majority carriers in the doped polysilicon layer 121 are then transported to the back electrode 107, which is in electrical contact with the doped polysilicon layer 121, and are collected by the back electrode 107.

[0132] In some embodiments, the material of the back electrode 107 may be a metal, such as copper, silver, nickel or aluminum.

[0133] In this embodiment, the electrodes of the solar cell are formed by a first sub-electrode 103 and a second sub-electrode 104. The first sub-electrode 103, which penetrates the passivation layer 102, is arranged at intervals along the first direction X and the second direction Y. The second sub-electrode 104 is in contact with the plurality of first sub-electrodes 103 arranged in the second direction Y. The first sub-electrode 103 and the second sub-electrode 104 can draw out the charge carriers inside the solar cell. The second sub-electrode 104 does not penetrate the passivation layer 102. That is to say, the first electrode formed by the first sub-electrode 103 and the second sub-electrode 104 only partially penetrates the passivation layer 102, thereby reducing the damaged area of ​​the passivation layer 102, thus ensuring the normal performance of the solar cell and improving the reliability of the solar cell. Secondly, by setting the second sub-electrode 104 to be composed of the first metal particle 114 and the second metal particle 124, and the material of the first metal particle 114 is different from that of the second metal particle 124, the cost of the solar cell can be controlled by controlling the materials of the first metal particle 114 and the second metal particle 124. Moreover, at least some of the first metal particle 114 and at least some of the second metal particle 124 are in electrical contact with the first sub-electrode 103, which will not affect the conductivity of the second sub-electrode 104.

[0134] Another embodiment of this disclosure also provides a method for manufacturing a solar cell. This method can be used to form the aforementioned solar cell wafer. It should be noted that the same or corresponding parts in the foregoing embodiments can be referred to the corresponding descriptions in the foregoing embodiments, and will not be repeated below.

[0135] refer to Figure 8 , Figure 8 This is a flowchart illustrating a method for manufacturing a solar cell according to an embodiment of the present disclosure.

[0136] Step S10, refer to Figure 9 , Figure 9 This is a schematic diagram of a method for forming a solar cell according to an embodiment of the present disclosure. In some embodiments, the method for forming a solar cell may include: providing a substrate 100.

[0137] Step S11, continue to refer to Figure 9 The method for fabricating a solar cell may further include: forming a doped conductive layer 101, wherein the doped conductive layer 101 is located within or on the surface of the substrate 100.

[0138] In some embodiments, before forming the doped conductive layer 101, the surface of the substrate 100 may be texturized to form a pyramid-like structure on the surface of the substrate 100.

[0139] In some embodiments, the doped conductive layer 101 is located on the front side, and the method of forming the doped conductive layer 101 may include: performing a doping treatment on the front side of the substrate 100, wherein the doping element is different from the doping element in the substrate 100, so as to convert a portion of the substrate 100 into an emitter 111, and the emitter 111 serves as the doped conductive layer 101.

[0140] In some embodiments, the doped conductive layer 101 is formed on the back side. Before forming the doped conductive layer 101, a tunneling layer 105 may be formed first. The tunneling layer 105 covers the surface of the substrate 100. Then, a polysilicon layer is deposited on the surface of the tunneling layer 105 and the polysilicon layer is doped to form a doped polysilicon layer 121, which serves as the doped conductive layer 101.

[0141] Step S12, continue to refer to Figure 9 The method for fabricating a solar cell may further include: forming a passivation layer 102, wherein the passivation layer 102 is located on the surface of the doped conductive layer 101.

[0142] In some embodiments, a passivation layer 102 can be formed on the surface of the doped conductive layer 101 by deposition.

[0143] Reference Figure 9 and Figure 10 ,in Figure 10 In order to be in Figure 9 The diagram shows the structure after high-temperature sintering.

[0144] Step S13, the method for fabricating a solar cell may further include: forming a plurality of first sub-electrodes 103, each first sub-electrode 103 at least partially penetrating the passivation layer 102 and contacting the doped conductive layer 101, the first sub-electrodes 103 being arranged at intervals along the first direction X and the second direction Y.

[0145] In some embodiments, a method for forming a plurality of first sub-electrodes 103 includes: performing a first printing process to print a burn-through paste to form an initial first sub-electrode 143; and performing a high-temperature sintering process to transform the initial first sub-electrode 143 into a first sub-electrode 103. The first sub-electrode 103 is formed by printing a burn-through paste and performing a high-temperature sintering process to form at least partially penetrating the passivation layer 102.

[0146] In some embodiments, glass powder in the burn-through slurry is fused with the passivation layer 102 on the surface of the solar cell to form a glass layer 123 after a high-temperature sintering process. The third metal particles precipitated in the slurry are distributed inside the glass layer 123 and at the interface between the glass layer 123 and the doped conductive layer 101, forming a metal-semiconductor contact with the doped conductive layer 101.

[0147] In some embodiments, the peak temperature of the high-temperature sintering process can be greater than or equal to 700°C. By setting the peak temperature of the high-temperature sintering process to be greater than or equal to 700°C, it is ensured that the formed first sub-electrode 103 at least partially penetrates the passivation layer 102 to make contact with the doped conductive layer 101.

[0148] Reference Figure 11 and Figure 12 ,in, Figure 11 To form a schematic diagram of the structure corresponding to the initial second sub-electrode. Figure 12 This is a schematic diagram of the structure after the drying process.

[0149] Step S14, the method for manufacturing a solar cell may further include: forming a plurality of second sub-electrodes 104, each second sub-electrode 104 extending along a second direction and contacting and connecting with a plurality of first sub-electrodes 103 arranged in the second direction, the second sub-electrode 104 comprising: a first metal particle 114, at least a portion of the first metal particle 114 being in electrical contact with the first sub-electrode 103, and a second metal particle 124, at least a portion of the second metal particle 124 being in electrical contact with the first sub-electrode 103, the material of the first metal particle 114 being different from the material of the second metal particle 124, the first sub-electrode 103 and the second sub-electrode 104 constituting a first electrode.

[0150] In some embodiments, the method for forming a plurality of second sub-electrodes 104 may include: performing a second printing process to print a non-burn-through paste to form an initial second sub-electrode 134; and performing a drying process to convert the initial second sub-electrode 134 into a second sub-electrode 104, wherein the process temperature of the high-temperature sintering process is higher than the process temperature of the drying process. It is understood that burn-through pastes require higher temperatures to etch the surface film and precipitate metal particles; non-burn-through pastes do not require high temperatures to damage the silicon surface, and only require drying the organic solvent in the paste at a lower temperature after printing. Furthermore, by setting the process temperature of the drying process to be lower than the process temperature of the high-temperature sintering process, damage to the passivation layer 102 during the formation of the second sub-electrode 104 can be avoided, thereby improving the reliability of the solar cell fabrication method.

[0151] In some embodiments, after the drying process, a contact enhancement process is further included, which includes: laser irradiating the portion of the first sub-electrode 103 that contacts the doped conductive layer 101, and adding an external electric field to the second sub-electrode 104 to form a contact structure on the contact surface between the first sub-electrode 103 and the doped conductive layer 101.

[0152] For example, a reverse bias voltage can be added to the positive electrode of the solar cell to form an external electric field pointing from the N-type region to the P-type region inside the PN junction of the solar cell. A laser can be used to irradiate the part where the first sub-electrode 103 contacts the doped conductive layer 101 to form a thermal effect generated by photocurrent locally. This forms a contact structure (e.g., silver-silicon alloy) at the part where the first sub-electrode 103 contacts the doped conductive layer 101, thereby increasing the reliability of the contact between the first sub-electrode 103 and the doped conductive layer 101 and increasing the reliability of carrier transport.

[0153] In some embodiments, the process parameters of the contact enhancement process include: the wavelength of the laser is 632–1550 nm, and the laser is a monochromatic laser or a mixed laser. By controlling the wavelength of the laser to be 632–1550 nm, and the laser to be a monochromatic laser or a mixed laser, the photogenerated current density generated by the local irradiation of the first sub-electrode 103 in contact with the doped conductive layer 101 is controlled to be 20,000–45,000 A / cm², thereby controlling the formation of a contact structure at the contact portion of the first sub-electrode 103 and the doped conductive layer 101, thereby increasing the reliability of the contact between the first sub-electrode 103 and the doped conductive layer 101, and increasing the reliability of carrier transport.

[0154] It should be noted that in the attached diagram, the back electrode is formed before the first sub-electrode is formed. In reality, the first and second sub-electrodes can also be back electrodes, or the first and second sub-electrodes can be formed first and then the back electrode can be formed. The diagram is just an example.

[0155] In some embodiments, this disclosure also provides a photovoltaic module, which may include the solar cells in some or all of the above embodiments, or include a solar cell formed by the manufacturing method of the solar cells in some or all of the above embodiments. It should be noted that the same or corresponding parts in the foregoing embodiments can be referred to the corresponding descriptions in the foregoing embodiments, and will not be repeated below.

[0156] refer to Figure 13 and Figure 14 , Figure 13 This is a schematic diagram of the structure of a photovoltaic module provided in one embodiment of the present disclosure. Figure 14 For along Figure 13 Cross-sectional view along the M1M2 direction.

[0157] In some embodiments, a photovoltaic module may include: a battery string, which is formed by connecting solar cells 300 in some or all of the embodiments described above, or a string of solar cells manufactured by the method for manufacturing solar cells described in some or all of the embodiments above.

[0158] The photovoltaic module may also include: an encapsulation layer 301 for covering the surface of the cell string.

[0159] The photovoltaic module may also include: a cover plate 302 for covering the surface of the encapsulation layer 301 away from the cell string.

[0160] In some embodiments, adjacent solar cells may be connected by solder strips.

[0161] Solar cells can be monocrystalline silicon solar cells, polycrystalline silicon solar cells, amorphous silicon solar cells, or multi-component compound solar cells. Specifically, multi-component compound solar cells can be cadmium sulfide solar cells, gallium arsenide solar cells, copper indium selenide solar cells, or perovskite solar cells. Furthermore, solar cells can be monolithic cells or sliced ​​cells; sliced ​​cells refer to cells formed from a single, monolithic cell through a cutting process.

[0162] In some embodiments, the encapsulation layer 301 includes a first encapsulation layer and a second encapsulation layer. The first encapsulation layer covers one of the front or back sides of the solar cell 300, and the second encapsulation layer covers the other of the front or back sides of the solar cell 300. Specifically, at least one of the first encapsulation layer or the second encapsulation layer may be an organic encapsulation layer such as polyvinyl butyral (PVB) film, ethylene-vinyl acetate copolymer (EVA) film, polyvinyl octene coelastomer (POE) film, or polyethylene terephthalate (PET) film.

[0163] It is understandable that there is a boundary between the first encapsulation layer and the second encapsulation layer before lamination. After lamination, the photovoltaic module will no longer have the concept of a first encapsulation layer and a second encapsulation layer. The first encapsulation layer and the second encapsulation layer have formed an integral encapsulation layer 301.

[0164] In some embodiments, the cover plate 302 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 302 facing the encapsulation layer 301 can be an uneven surface, thereby increasing the utilization rate of incident light. The cover plate 302 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.

[0165] 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 solar cell, characterized in that, include: Substrate; A doped conductive layer, wherein the doped conductive layer is located within or on the surface of the substrate; A passivation layer, wherein the passivation layer is located on the surface of the doped conductive layer; A plurality of first sub-electrodes, each first sub-electrode at least partially penetrating the passivation layer and contacting the doped conductive layer, the first sub-electrodes being arranged at intervals along a first direction and a second direction; A plurality of second sub-electrodes, each second sub-electrode extending along a second direction and contacting and connecting with a plurality of first sub-electrodes arranged along the second direction, the second sub-electrode comprising: a first metal particle, at least a portion of the first metal particle being in electrical contact with the first sub-electrode, and a second metal particle, at least a portion of the second metal particle being in electrical contact with the first sub-electrode, the material of the first metal particle being different from the material of the second metal particle, the first sub-electrode and the second sub-electrode constituting a first electrode; The first sub-electrode includes: a third metal particle that is in contact with the doped conductive layer; a glass layer that is located on the surface of the doped conductive layer and covers the surface of the third metal particle; and an electrode body that is located on the surface of the glass layer and is in contact with the third metal particle.

2. The solar cell according to claim 1, characterized in that, The second sub-electrode is located on the surface of the passivation layer, and the second sub-electrode is in contact with at least one side of the first sub-electrode that protrudes from the passivation layer and is opposite to it along the second direction.

3. The solar cell according to claim 2, characterized in that, The second sub-electrode also contacts the side of the first sub-electrode that protrudes from the passivation layer and is opposite to it along the first direction.

4. The solar cell according to any one of claims 1 to 3, characterized in that, The second sub-electrode also covers the top surface of the first sub-electrode.

5. The solar cell according to claim 1, characterized in that, In the second direction, the ratio of the length of the second sub-electrode to the length of all the first sub-electrodes in contact with the second sub-electrode is 4:3 to 10:

1.

6. The solar cell according to claim 1, characterized in that, The number of second sub-electrodes is multiple, and the multiple second sub-electrodes are arranged at intervals, with the spacing between two adjacent second sub-electrodes being greater than the width of the second sub-electrodes in the first direction.

7. The solar cell according to claim 1, characterized in that, In the second direction, the ratio of the area of ​​the second sub-electrode projected onto the substrate surface to the area of ​​all the first sub-electrodes in contact with the second sub-electrode projected onto the substrate surface is 4:3 to 100:

1.

8. The solar cell according to claim 1, characterized in that, The orthographic projection of the first sub-electrode on the substrate surface lies within the orthographic projection of the second sub-electrode on the substrate surface.

9. The solar cell according to claim 1, characterized in that, In the first direction, the width of the first sub-electrode is greater than the width of the second sub-electrode.

10. The solar cell according to claim 1, characterized in that, The material of the third metal particle is the same as that of the first metal particle.

11. The solar cell according to claim 1, characterized in that, The diameter of the third metal particle is 10~20nm.

12. The solar cell according to claim 1, characterized in that, The first metal particle is a silver particle, and the second metal particle is a silver-coated copper particle.

13. The solar cell according to claim 1, characterized in that, Also includes: A tunneling layer is located on the surface of the substrate, and a doped conductive layer is located on the surface of the tunneling layer.

14. A method for manufacturing a solar cell, characterized in that, include: Provide substrate; A doped conductive layer is formed, the doped conductive layer being located within or on the surface of the substrate; A passivation layer is formed on the surface of the doped conductive layer; A plurality of first sub-electrodes are formed, each first sub-electrode at least partially penetrating the passivation layer and contacting the doped conductive layer, and the first sub-electrodes are arranged at intervals along a first direction and a second direction; A plurality of second sub-electrodes are formed, each second sub-electrode extending along the second direction and contacting and connecting with a plurality of first sub-electrodes arranged along the second direction. The second sub-electrode includes: a first metal particle, at least a portion of which is in electrical contact with the first sub-electrode; and a second metal particle, at least a portion of which is in electrical contact with the first sub-electrode. The material of the first metal particle is different from the material of the second metal particle. The first sub-electrode and the second sub-electrode constitute a first electrode. The first sub-electrode includes: a third metal particle that is in contact with the doped conductive layer; a glass layer that is located on the surface of the doped conductive layer and covers the surface of the third metal particle; and an electrode body that is located on the surface of the glass layer and is in contact with the third metal particle.

15. The method for manufacturing a solar cell according to claim 14, characterized in that, The method for forming a plurality of first sub-electrodes includes: The first printing process is performed to print a burn-through paste to form the initial first sub-electrode; A high-temperature sintering process is performed to transform the initial first sub-electrode into the first sub-electrode.

16. The method for manufacturing a solar cell according to claim 15, characterized in that, The method for forming a plurality of second sub-electrodes includes: A second printing process is performed to print a non-burn-through paste to form the initial second sub-electrode; A drying process is performed to transform the initial second sub-electrode into the second sub-electrode, wherein the process temperature of the high-temperature sintering process is higher than the process temperature of the drying process.

17. The method for manufacturing a solar cell according to claim 16, characterized in that, The process further includes a contact enhancement process after the drying process. The contact enhancement process includes laser irradiation of the portion of the first sub-electrode that contacts the doped conductive layer, and an external electric field applied to the second sub-electrode to form a contact structure on the contact surface between the first sub-electrode and the doped conductive layer.

18. The method for manufacturing a solar cell according to claim 17, characterized in that, The process parameters of the contact enhancement process include: the wavelength of the laser is 632~1550nm, and the laser is a monochromatic laser or a mixed laser.

19. A photovoltaic module, characterized in that, include: A battery string, formed by connecting solar cells according to any one of claims 1 to 13, or formed by connecting solar cells manufactured by the method of manufacturing solar cells according to any one of claims 14 to 18; An encapsulation layer is used to cover the surface of the battery string; A cover plate is used to cover the surface of the encapsulation layer that faces away from the battery string.

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