Solar cell and photovoltaic module

Abstract

The embodiment of the invention relates to the photovoltaic field, and provides a solar cell piece and a photovoltaic module, and the solar cell piece comprises a substrate; the doped conductive layer is positioned on one side of the substrate; the passivation layer covers the surface, away from the substrate, of the doped conductive layer; the electrodes comprise a plurality of bottom electrodes which are arranged at intervals in the first direction, and the bottom electrodes are electrically connected with the doped conductive layer; the top electrode extends in the first direction, the top electrode covers the surface of the bottom electrode, the surface, away from the substrate, of the top electrode is in a wave shape and comprises at least one wave crest and at least one wave trough, the wave trough of the top electrode directly faces the at least one bottom electrode, and the wave crest of the top electrode directly faces the interval of the at least one bottom electrode. The cost can be reduced, and the battery performance is ensured.

Description

Technical Field

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

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

[0003] The embodiments of the present disclosure provide a solar cell and a photovoltaic module, which can at least reduce the cost of the solar cell while avoiding affecting the transmission performance of the solar cell.

[0004] According to some embodiments of the present disclosure, on one hand, the embodiments of the present disclosure provide a solar cell, comprising: a substrate; a doped conductive layer, the doped conductive layer being located on one side of the substrate; a passivation layer, the passivation layer covering the surface of the doped conductive layer away from the substrate; an electrode, the electrode comprising: a plurality of bottom electrodes arranged at intervals along a first direction, the bottom electrodes being electrically connected to the doped conductive layer; a top electrode extending along the first direction, the top electrode covering the surface of the bottom electrode, and the surface of the top electrode away from the substrate being wavy and comprising at least one crest and at least one trough, the trough of the top electrode being opposite to at least one bottom electrode, and the crest of the top electrode being opposite to at least the interval of the bottom electrode.

[0005] In some embodiments, the top electrode covers the surface of the passivation layer, the bottom electrode is convex away from the top of the substrate, and the trough of the top electrode is opposite to the top of the bottom electrode.

[0006] In some embodiments, a valley of the top electrode faces a bottom electrode, and a peak of the top electrode faces a gap of the bottom electrode.

[0007] In some embodiments, it also includes: a second bottom electrode, the second bottom electrode is located between the bottom electrodes and connected to the bottom electrode, the bottom electrode covers the surface of the passivation layer, the bottom electrode is convex downward away from the top of the substrate, and the second bottom electrode is convex upward away from the top of the substrate.

[0008] In some embodiments, a valley of the top electrode faces at least one of the bottom electrodes and at least one of the second bottom electrodes, and a peak of the top electrode faces at least one of the bottom electrodes and at least one of the second bottom electrodes.

[0009] In some embodiments, a trough of the top electrode faces 2 to 10 of the bottom electrodes and 2 to 10 of the second bottom electrodes, and a peak of the top electrode faces 2 to 10 of the bottom electrodes and 2 to 10 of the second bottom electrodes.

[0010] In some embodiments, a height difference between a top portion of the bottom electrode and a bottom portion of the second bottom electrode is 1 μm-10 μm.

[0011] In some embodiments, the interval between adjacent bottom electrodes is 0 μm-200 μm.

[0012] In some embodiments, a portion of the bottom electrode is located in the doped conductive layer, and a depth of the bottom electrode in the doped conductive layer is 20 nm to 200 nm.

[0013] In some embodiments, the thickness of the electrode is 5 μm to 25 μm.

[0014] In some embodiments, the height difference between the crest and the trough of the top electrode is 4 μm to 20 μm.

[0015] In some embodiments, in the second direction, the width of the bottom electrode is greater than or equal to the width of the top electrode, and the first direction and the second direction form an angle.

[0016] In some embodiments, a portion of the top electrode has an orthographic projection on the substrate surface that is arc-shaped.

[0017] According to some embodiments of the present disclosure, another aspect of the present disclosure provides a photovoltaic assembly, comprising: a cell string, the cell string comprising: a plurality of solar cells as described above; a welding ribbon, the welding ribbon being electrically connected to at least two solar cells to connect adjacent solar cells in series; an encapsulation film, the encapsulation film being used to cover a surface of the cell string; and a cover plate, the cover plate being used to cover a surface of the encapsulation film away from the cell string.

[0018] The technical solution provided by the embodiments of the present disclosure has at least the following advantages: the electrodes are provided to include a non-common bottom electrode and a top electrode, and are in contact with the doped conductive layer only through the bottom electrode. Moreover, the spacing arrangement of the bottom electrodes can also reduce the consumption of electrode slurry, thereby reducing the cost of the solar cell. At the same time, the corresponding part of the bottom electrode has a certain thickness. Therefore, the trough position of the top electrode can be set to face the bottom electrode to reduce the consumption of the top electrode slurry. At the same time, the peak of the top electrode is set to face the interval of the bottom electrode to compensate for the transmission performance of the interval position, thereby reducing the cost of the electrode while ensuring the transmission performance of the electrode. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] One or more embodiments are exemplarily illustrated by the pictures in the corresponding drawings. These exemplified descriptions do not constitute a limitation on the embodiments. Unless otherwise stated, the pictures in the drawings do not constitute a scale limitation. In order to more clearly illustrate the embodiments of the present disclosure or the technical solutions in the traditional technology, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0020] Figure 1 A top view of a solar cell provided in one embodiment of the present disclosure; Figure 2 A cross-sectional view of a solar cell provided in accordance with an embodiment of the present disclosure; Figure 3 A cross-sectional view of a second solar cell provided in accordance with an embodiment of the present disclosure; Figure 4 A cross-sectional view of a third solar cell provided in an embodiment of the present disclosure; Figure 5 A partial three-dimensional schematic diagram of a photovoltaic assembly provided by an embodiment of the present disclosure; Figure 6 A cross-sectional view of a photovoltaic module provided in one embodiment of the present disclosure.

[0021] Description of reference numerals: 100, substrate; 101, doped conductive layer; 102, passivation layer; 103, electrode; 113, bottom electrode; 123, top electrode; 104, tunneling layer; 133, second bottom electrode.

[0022] 40. Solar cell; 41. Encapsulation film; 42. Cover plate; 43. Solder ribbon. DETAILED DESCRIPTION

[0023] Currently, the electrodes of solar cells are usually screen-printed, and since the electrodes of the entire solar cell are silver paste, the silver consumption of each cell is large, and it is necessary to reduce the use of solar cell paste.

[0024] The technical solution provided by the embodiments of the present disclosure has at least the following advantages: the electrodes are provided to include a non-common bottom electrode and a top electrode, and are in contact with the doped conductive layer only through the bottom electrode. Moreover, the spacing arrangement of the bottom electrodes can also reduce the consumption of electrode slurry, thereby reducing the cost of the solar cell. At the same time, the corresponding part of the bottom electrode has a certain thickness. Therefore, the trough position of the top electrode can be set to face the bottom electrode to reduce the consumption of the top electrode slurry. At the same time, the peak of the top electrode is set to face the interval of the bottom electrode to compensate for the transmission performance of the interval position, thereby reducing the cost of the electrode while ensuring the transmission performance of the electrode.

[0025] In the description of the embodiments of the present disclosure, technical terms such as "first" and "second" are used solely to distinguish between different objects and should not be understood to indicate or imply relative importance or to implicitly specify the quantity, specific order, or primary and secondary relationship of the technical features indicated. In the description of the embodiments of the present disclosure, "plurality" means more than two, unless otherwise specifically defined.

[0026] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present disclosure. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0027] In the description of the embodiments of the present disclosure, the term "and / or" is merely a description of an association relationship between associated objects, indicating that three relationships may exist. For example, A and / or B can represent the following three situations: A exists, A and B exist at the same time, and B exists. In addition, the character " / " in this document generally indicates that the associated objects are in an "or" relationship.

[0028] In the description of the embodiments of the present disclosure, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0029] In the description of the embodiments of the present disclosure, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present disclosure and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be understood as limiting the embodiments of the present disclosure.

[0030] In the description of the embodiments of the present disclosure, unless otherwise expressly specified or limited, technical terms such as "installed," "connected," "connected," and "fixed" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and they can refer to internal connectivity between two components or interaction between two components. Those skilled in the art can understand the specific meanings of the above terms in the embodiments of the present disclosure based on specific circumstances.

[0031] In the accompanying drawings corresponding to the embodiments of the present disclosure, the thickness and area of ​​layers are exaggerated for better understanding and ease of description. When a component (such as a layer, film, region, or substrate) is described as being on or on the surface of another component, the component may be "directly" located on the surface of the other component, or a third component may be present between the two components. Conversely, when a component is described as being on the surface of another component, or as being formed or disposed on the surface of one component, it indicates that there is no third component between the two components. Furthermore, when a component is described as being "substantially" formed on another component, this means that the component is not formed on the entire surface (or front surface) of the other component, nor is it formed on a portion of the edge of the entire surface.

[0032] In the description of the embodiments of the present disclosure, when a component is referred to as "including" another component, unless otherwise specified, this does not exclude other components, and other components may further be included. Furthermore, when a component such as a layer, film, region, or plate is referred to as being "on" another component, it may be "directly on" the other component (i.e., located on the surface of the other component with no other components between them) or another component may be present between them. Furthermore, when a component such as a layer, film, region, or plate is referred to as being "directly on" another component, or when a component such as a layer, film, region, or plate is located on the surface of another component, this means that no other components are located between them.

[0033] The terms used in the description of the various embodiments described herein are intended only to describe the specific embodiments and are not intended to be limiting. As used in the description and claims of the various embodiments described herein, "the component" is intended to include the plural form unless the context clearly indicates otherwise. A component includes a layer, film, region, or plate.

[0034] The following describes various embodiments of the present disclosure in detail with reference to the accompanying drawings. However, those skilled in the art will appreciate that many technical details are provided in the various embodiments of the present disclosure to facilitate a better understanding of the present disclosure. However, even without these technical details and the various variations and modifications based on the following embodiments, the technical solutions claimed in the present disclosure can still be implemented.

[0035] refer to Figures 1 to 4 , Figure 1 A top view of a solar cell provided in one embodiment of the present disclosure; Figure 2 An embodiment of the present disclosure provides Figure 1 Cross-sectional view of a solar cell in the MM1 direction; Figure 3 An embodiment of the present disclosure provides Figure 1 Cross-sectional view of the second type of solar cell in the MM1 direction; Figure 4 An embodiment of the present disclosure provides Figure 1 Cross-sectional view of the third type of solar cell in the MM1 direction.

[0036] In some embodiments, a solar cell may include a substrate 100 .

[0037] The solar cell may further include: a doped conductive layer 101 , which is located on one side of the substrate 100 .

[0038] The solar cell may further include a passivation layer 102 , which covers the surface of the doped conductive layer 101 away from the substrate 100 .

[0039] The solar cell may further include: an electrode 103, the electrode 103 including: a plurality of bottom electrodes 113 spaced apart along a first direction, the bottom electrodes 113 being electrically connected to the doped conductive layer 101; a top electrode 123 extending along the first direction, the top electrode 123 covering the surface of the bottom electrode 113, and the surface of the top electrode 123 away from the substrate 100 is wavy, and includes at least one crest and at least one trough, the trough of the top electrode 123 is opposite to at least one bottom electrode 113, and the crest of the top electrode 123 is opposite to the interval of at least one bottom electrode 113.

[0040] The technical solution provided by the embodiment of the present disclosure has at least the following advantages: the electrode 103 is provided to include a non-common bottom electrode 113 and a top electrode 123, and is in contact with the doped conductive layer 101 only through the bottom electrode 113. Moreover, since the bottom electrodes 113 are arranged at intervals, the consumption of the electrode 103 slurry can be reduced, thereby reducing the cost of the solar cell. At the same time, the corresponding part of the bottom electrode 113 has a certain thickness. Therefore, the trough position of the top electrode 123 can be set to be opposite to the bottom electrode 113 to reduce the consumption of the top electrode 123 slurry. At the same time, the peak of the top electrode 123 is set to be opposite to the interval of the bottom electrode 113 to compensate for the transmission performance of the interval position, thereby reducing the cost of the electrode 103 while ensuring the transmission performance of the electrode 103.

[0041] In some embodiments, the solar cell may be any one of a PERC cell (Passivated Emitter and Rear Cell), a PERT cell (Passivated Emitter and Rear Totally-diffused cell), a TOPCon cell (Tunnel Oxide Passivated Contact), a HIT / HJT cell (Heterojunction Technology), or a BC cell (Back Contact). In other embodiments, the solar cell may be a stacked cell comprising any of the above cells (wherein the top cell is a perovskite cell and the bottom cell is any of the above cells), or a half-cell of any of the above cells, etc.

[0042] In some embodiments, the cell is a single-sided cell, in which case the front side of the substrate 100 can serve as the light-receiving surface for receiving incident light, and the back side can serve as the backlight surface. In some embodiments, the cell is a double-sided cell, in which case both the front side and the back side of the substrate 100 can serve as the light-receiving surface for receiving incident light. It is understood that the backlight surface referred to in the embodiments of the present disclosure can also receive incident light, but the degree of reception of the incident light is weaker than that of the light-receiving surface, and therefore is defined as the backlight surface.

[0043] In some embodiments, a texturing process can be performed on at least one of the front or back surfaces of the substrate 100 to form a velvet surface on at least one of the front or back surfaces of the substrate 100. This can enhance the absorption efficiency of incident light by the front and back surfaces of the substrate 100. In some embodiments, the velvet surface can be a pyramid velvet surface. As a common velvet surface, the pyramid velvet surface not only reduces the reflectivity of the surface of the substrate 100 but also forms light traps, enhancing the substrate 100's absorption of incident light and improving the photoelectric conversion efficiency of the solar cell.

[0044] In some embodiments, the solar cell may further include a tunneling layer 104, which is located between the substrate 100 and the doped conductive layer 101, so that the tunneling layer 104 has a chemical passivation effect on the back side of the substrate 100, specifically by saturating the dangling bonds on the back side of the substrate 100, reducing the defect state density on the back side of the substrate 100, and reducing the recombination centers on the surface of the substrate 100 to reduce the carrier recombination rate.

[0045] In some embodiments, the material of the tunneling layer 104 may include at least one of silicon oxide, silicon nitride, silicon oxynitride, silicon carbide, or magnesium fluoride.

[0046] The material of the doped conductive layer 101 may include at least one of amorphous silicon, polycrystalline silicon, or silicon carbide.

[0047] The doped conductive layer 101 may be doped with the same type of doping element as the substrate 100. For example, if the doping element type of the substrate 100 is P-type, the doping element type of the doped conductive layer 101 may also be P-type; if the doping element type of the substrate 100 is N-type, the doping element type of the doped conductive layer 101 may also be N-type. The doped conductive layer 101 may be doped with a different type of doping element than the substrate 100. For example, if the doping element type of the substrate 100 is P-type, the doping element type of the doped conductive layer 101 may also be N-type; if the doping element type of the substrate 100 is N-type, the doping element type of the doped conductive layer 101 may also be P-type.

[0048] In some embodiments, the doped conductive layer 101 may be located on a side surface of the substrate 100 . In other embodiments, the doped conductive layer 101 may be located within the substrate 100 .

[0049] The solar cell may further include a passivation layer 102, which covers the surface of the doped conductive layer 101 away from the substrate 100. The passivation layer 102 can effectively passivate the back surface of the substrate 100. For example, it can effectively chemically passivate the dangling bonds on the back surface of the substrate 100, saturate the dangling bonds on the back surface of the substrate 100, reduce the defect state density on the back surface of the substrate 100, and inhibit carrier recombination on the back surface of the substrate 100.

[0050] The material of the passivation layer 102 may be silicon oxide, aluminum oxide, silicon nitride or silicon oxynitride.

[0051] The passivation layer 102 may be a single-layer structure or a multi-layer structure. For a multi-layer structure, the materials of different layers may be different from each other, or the materials of some layers may be the same but different from the materials of other layers. For example, the passivation layer 102 may be a multi-layer structure of a silicon nitride layer and an aluminum oxide layer.

[0052] In some embodiments, the top electrode 123 covers the surface of the passivation layer 102 , the bottom electrode 113 is convex away from the top of the substrate 100 , and the valley of the top electrode 123 faces the top of the bottom electrode 113 . The top electrode 123 covers the surface of the passivation layer 102, that is, the electrode 103 is electrically connected to the doped conductive layer 101 only through the bottom electrode 113, and the bottom electrode 113 is arranged to be convex downward away from the top of the substrate 100, that is, the bottom electrode 113 is arranged to protrude in the direction away from the substrate 100, and the trough of the top electrode 123 is arranged to be opposite to the top of the substrate 100, that is, the trough of the top electrode 123 is electrically connected to the bottom electrode 113. It can be understood that since the bottom electrode 113 has a certain thickness, even if the trough of the top electrode 123 is arranged to be electrically connected to the bottom electrode 113, the part of the electrode 103 corresponding to the bottom electrode 113 has sufficient thickness and will not affect the transmission efficiency of the electrode 103. At the same time, the presence of the trough of the top electrode 123 also reduces the use of the top electrode 123 slurry, and can also reduce the cost of the solar cell.

[0053] In some embodiments, a trough of the top electrode 123 is directly opposite to a bottom electrode 113, and a peak of the top electrode 123 is directly opposite to a gap between the bottom electrodes 113. For the top electrode 123, the portion corresponding to the trough is the portion with poor transmission capability of the top electrode 123. Therefore, by having the trough directly opposite to the bottom electrode 113, the bottom electrode 113 is used to compensate for the transmission capability of the top electrode 123. The peak of the top electrode 123 is the portion with better transmission capability of the top electrode 123. By having the top electrode 123 directly opposite to the gap between the bottom electrodes 113, since the gap is not provided with the bottom electrode 113, the portion with better transmission capability is used to directly face the gap, thereby balancing the transmission capability of the entire electrode 103. By having a trough directly opposite to a bottom electrode 113 and a peak directly opposite to a gap, the cost of the solar cell can be reduced while avoiding affecting the performance of the solar cell.

[0054] It should be noted that the "facing" here may refer to the trough being completely facing the bottom electrode 113, or it may refer to the situation where the trough and the bottom electrode 113 are partially offset. Within the allowable offset range, the trough and the bottom electrode 113 may also be regarded as facing each other. The allowable offset range here means: taking the surface morphology of the top electrode 123 away from the substrate 100 as an example, the trough and the bottom electrode 113 may be regarded as facing each other if the offset size between the trough and the bottom electrode 113 is less than or equal to 1 / 8 of the sine period.

[0055] In some embodiments, the bottom electrode 113 is convex downward away from the top of the substrate 100, a trough of the top electrode 123 is opposite to a bottom electrode 113, and a peak of the top electrode 123 is opposite to the interval between the bottom electrodes 113. It can also mean that: the lowest point of the trough is opposite to the highest point of the bottom electrode 113, and the highest point of the top electrode 123 is opposite to the center point of the interval between the bottom electrodes 113.

[0056] In some embodiments, the solar cell may further include a second bottom electrode 133. The second bottom electrode 133 is located between the bottom electrodes 113 and is connected to the bottom electrode 113. The bottom electrode 113 covers the surface of the passivation layer 102. The bottom electrode 113 is convex downward away from the top of the substrate 100, while the second bottom electrode 133 is convex upward away from the top of the substrate 100. In other words, the top electrode 123 is spaced apart from the passivation layer 102, and the bottom electrode 113 and the second bottom electrode 133 together form a wavy structure. On the one hand, the second bottom electrode 133 can improve the reliability of transmission between the bottom electrode 113 and the top electrode 123. When the transmission between any bottom electrode 113 and the top electrode 123 is abnormal, the second bottom electrode 133 can be used to conduct the abnormal transmission path. On the other hand, the second bottom electrode 133 can also reduce the contact resistance between the bottom electrode 113 and the top electrode 123, thereby reducing the transmission loss of carriers in the solar cell by increasing the contact area.

[0057] In some embodiments, the second bottom electrode 133 and the bottom electrode 113 can be an integrated structure, that is, the bottom electrode 113 and the second bottom electrode 133 can be formed in the same process step, thereby improving the reliability of the connection between the bottom electrode 113 and the second bottom electrode 133.

[0058] It can be understood that the bottom electrode 113 is convex downward away from the top of the substrate 100, and the second bottom electrode 133 is convex upward away from the top of the substrate 100, that is, the bottom electrode 113 constitutes a crest, and the second bottom electrode 133 constitutes a trough, and the crest of the top electrode 123 is opposite to the interval of the bottom electrode 113, that is, the crest of the top electrode 123 is opposite to the second bottom electrode 133.

[0059] Further, when a trough of the top electrode 123 is opposite to a bottom electrode 113, and a peak of the top electrode 123 is opposite to a second bottom electrode 133, that is to say, the trough of the top electrode 123 is opposite to the peak of the bottom electrode 113, and the peak of the top electrode 123 is opposite to the trough of the second bottom electrode 133, in other words, the bottom electrode 113 and the second bottom electrode 133 are regarded as a whole, the wavy peak of the top electrode 123 is embedded in the overall trough between the bottom electrode 113 and the second bottom electrode 133, and the wavy trough of the top electrode 123 is embedded in the overall peak between the bottom electrode 113 and the second bottom electrode 133. In this way, the portion corresponding to the trough is the portion of the top electrode 123 with poor transmission capability. Therefore, by aligning the trough with the bottom electrode 113, the bottom electrode 113 is used to compensate for the transmission capability of the top electrode 123. The peak of the top electrode 123 is the portion with better transmission capability of the top electrode 123. By aligning the trough of the top electrode 123 with the second bottom electrode 133, the transmission capability of the entire electrode 103 can be balanced. By setting a trough to be opposite to a bottom electrode 113 and a peak to be opposite to a second bottom electrode 133, the cost of the solar cell can be reduced while avoiding affecting the performance of the solar cell.

[0060] In some embodiments, a trough of the top electrode 123 directly faces at least one bottom electrode 113 and at least one second bottom electrode 133, and a crest of the top electrode 123 directly faces at least one bottom electrode 113 and at least one second bottom electrode 133. In other words, an upwardly convex portion of the top electrode 123 directly faces at least one bottom electrode 113 and at least one second bottom electrode 133, and a downwardly convex portion of the top electrode 123 directly faces at least one bottom electrode 113 and at least one second bottom electrode 133. If the bottom electrode 113 and the second bottom electrode 133 are considered as a whole, the troughs of the top electrode 123 and the crests of the entire region between the bottom electrode 113 and the second bottom electrode 133 are not in a one-to-one correspondence. Instead, the troughs of the top electrode 123 correspond to at least one period of the entire region between the bottom electrode 113 and the second bottom electrode 133, and the crests of the top electrode 123 correspond to at least one period of the entire region between the bottom electrode 113 and the second bottom electrode 133. In this way, the transmission performance of the electrode 103 can be guaranteed while reducing the amount of slurry in the electrode 103. Moreover, a trough of the top electrode 123 is arranged to be opposite to at least one bottom electrode 113 and at least one second bottom electrode 133, and a peak of the top electrode 123 is arranged to be opposite to at least one bottom electrode 113 and at least one second bottom electrode 133. This can also reduce the difficulty of alignment in forming solar cells, thereby reducing the process difficulty of solar cells.

[0061] It should be noted that the upward convex portion of the top electrode 123 refers to the portion of the top electrode 123 whose thickness is less than or equal to the average thickness, and the downward convex portion of the top electrode 123 refers to the portion of the top electrode 123 whose thickness is greater than or equal to the average thickness. A whole period between the bottom electrode 113 and the second bottom electrode 133 refers to a period jointly constituted by the crest of the bottom electrode 113 and the trough of the second bottom electrode 133. Taking the overall morphology between the bottom electrode 113 and the second bottom electrode 133 as an example of a sinusoidal curve, it means that one period of the sinusoidal curve corresponds to the portion between the bottom electrode 113 and the second bottom electrode 133.

[0062] In some embodiments, the number of bottom electrodes 113 and second bottom electrodes 133 that are opposite to each period in the top electrode 123 may be different. For example, in one period of the top electrode 123, the trough of the top electrode 123 may be opposite to one bottom electrode 113 and one second bottom electrode 133, and the peak of the top electrode 123 may be opposite to one bottom electrode 113 and one second bottom electrode 133. In another period of the top electrode 123, the trough of the top electrode 123 may be opposite to two bottom electrodes 113 and two second bottom electrodes 133, and the peak of the top electrode 123 may be opposite to two bottom electrodes 113 and two second bottom electrodes 133.

[0063] In some embodiments, the number of peaks that face the bottom electrode 113 and the second bottom electrode 133 in each period of the top electrode 123 is different from the number of valleys that face the bottom electrode 113 and the second bottom electrode 133. For example, in the same period, the peaks of the top electrode 123 may face one bottom electrode 113 and one second bottom electrode 133, and the valleys of the top electrode 123 may face two bottom electrodes 113 and two second bottom electrodes 133.

[0064] In some embodiments, the number of valleys of the top electrode 123 that face the bottom electrodes 113 and the second bottom electrodes 133 may not be an integer. For example, a peak of the top electrode 123 may face 1.5 bottom electrodes 113 and 1.5 second bottom electrodes 133, and a valley of the top electrode 123 may face 1.5 bottom electrodes 113 and 1.5 second bottom electrodes 133.

[0065] In some embodiments, a trough of the top electrode 123 is opposite to 2-10 bottom electrodes 113 and 2-10 second bottom electrodes 133, and a crest of the top electrode 123 is opposite to 2-10 bottom electrodes 113 and 2-10 second bottom electrodes 133. For example, a trough of the top electrode 123 may be opposite to 2, 3, 4, 5, 6, 7, 8, 9 or 10 bottom electrodes 113, and the trough may also be opposite to 2, 3, 4, 5, 6, 7, 8, 9 or 10 second bottom electrodes 133, and a crest of the top electrode 123 may be opposite to 2, 3, 4, 5, 6, 7, 8, 9 or 10 bottom electrodes 113, and the crest may also be opposite to 2, 3, 4, 5, 6, 7, 8, 9 or 10 second bottom electrodes 133.

[0066] The greater the number of troughs of the top electrode 123 that face the bottom electrode 113 and the second bottom electrode 133, the larger the size spanned by the crests and troughs of the top electrode 123, which leads to greater difficulty in forming a structure with troughs. Similarly, the greater the number of crests of the top electrode 123 that face the bottom electrode 113 and the second bottom electrode 133, the greater the difficulty in forming a structure with crests. By controlling one trough to face 2 to 10 bottom electrodes 113 and 2 to 10 second bottom electrodes 133, and one crest to face 2 to 10 bottom electrodes 113 and 2 to 10 second bottom electrodes 133, the difficulty in forming the top electrode 123 can be reduced while reducing the required slurry for the top electrode 123.

[0067] In some embodiments, the height difference between the top of the bottom electrode 113 and the bottom of the second bottom electrode 133 is 1 μm to 10 μm, for example, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, or 9 μm. On the one hand, this can prevent the height difference between the bottom electrode 113 and the second bottom electrode 133 from being too large, thereby preventing the problem of a fault or gap between the bottom electrode 113 and the second bottom electrode 133, thereby improving the reliability of the connection between the bottom electrode 113 and the second bottom electrode 133. On the other hand, the height difference between the bottom electrode 113 and the second bottom electrode 133 can be used to control the cost of the bottom electrode 113 and the second bottom electrode 133, thereby achieving the purpose of reducing the cost of the solar cell.

[0068] The height difference between the top of the bottom electrode 113 and the bottom of the second bottom electrode 133 can be regarded as the amplitude of the overall topography curves of the bottom electrode 113 and the second bottom electrode 133 .

[0069] In some embodiments, the spacing between adjacent bottom electrodes 113 is 0 μm to 200 μm, for example, 10 μm, 30 μm, 50 μm, 100 μm, 150 μm, 180 μm, or 200 μm. A larger spacing between the bottom electrodes 113 results in a smaller contact area between the electrode 103 and the doped conductive layer 101, which affects carrier transport between the electrode 103 and the doped conductive layer 101. Therefore, the spacing between adjacent bottom electrodes 113 needs to be controlled to be less than 200 μm.

[0070] In some embodiments, a portion of the bottom electrode 113 is located within the doped conductive layer 101, and the depth of the bottom electrode 113 within the doped conductive layer 101 is 20 nm to 200 nm, such as 50 nm, 70 nm, 100 nm, 120 nm, 150 nm, 180 nm, or 200 nm. Regarding the electrode 103, since only the bottom electrode 113 is in contact and electrically connected to the doped conductive layer 101, and the bottom electrodes 113 are spaced apart from each other, this may affect the carrier transport capability. Therefore, a portion of the bottom electrode 113 is located within the doped conductive layer 101 to increase the contact area between the bottom electrode 113 and the doped conductive layer 101, thereby improving the transport performance between the doped conductive layer 101 and the electrode 103. At the same time, if the bottom electrode 113 is located too deep within the doped conductive layer 101, metal ions in the bottom electrode 113 may diffuse into the substrate 100, affecting the reliability of the solar cell.

[0071] In some embodiments, the thickness of the electrode 103 is 5 μm to 25 μm, for example, 8 μm, 10 μm, 12 μm, 15 μm, 20 μm, or 25 μm. The thickness of the electrode 103 may refer to the sum of the thicknesses of the bottom electrode 113 and the top electrode 123, or may refer to the thickness of the top electrode 123 corresponding to the spacing position. By controlling the thickness of the electrode 103, the slurry required to form the electrode 103 can be further controlled, thereby further controlling the cost of the solar cell.

[0072] In some embodiments, the height difference between the crest and the trough of the top electrode 123 is 4 μm to 20 μm, for example, 6 μm, 8 μm, 10 μm, 12 μm, 15 μm, 18 μm, or 20 μm. The greater the height difference between the crest and the trough of the top electrode 123, the more slurry is saved in the top electrode 123, and the more the cost of the solar cell is reduced. At the same time, the greater the height difference between the crest and the trough of the top electrode 123, the more likely it is that the top electrode 123 will have a fault or a reduced reliability due to a height mutation. Therefore, setting the height difference between the crest and the trough of the top electrode 123 to 4 μm to 20 μm can improve the reliability of the top electrode 123 while controlling the cost of the top electrode 123.

[0073] In some embodiments, in the second direction, the width of the bottom electrode 113 is greater than or equal to the width of the top electrode 123, and the first direction and the second direction form an angle. Setting the width of the bottom electrode 113 to be greater than or equal to the width of the top electrode 123 can facilitate alignment between the top electrode 123 and the electrode 103, reduce the difficulty of manufacturing solar cells, and on the other hand, improve the reliability of the contact between the bottom electrode 113 and the top electrode 123.

[0074] In some embodiments, a portion of the top electrode 123 has an arc-shaped orthographic projection on the surface of the substrate 100. Setting the top electrode 123 to have an arc-shaped orthographic projection on the surface of the substrate 100 can increase the contact area between the top electrode 123 and the bottom electrode 113, thereby reducing the contact resistance between the top electrode 123 and the bottom electrode 113, thereby improving the reliability of the solar cell.

[0075] In some embodiments, the orthographic projection of the top electrode 123 on the surface of the substrate 100 can be gourd-shaped or serpentine-shaped, wherein the gourd-shaped shape means that the width dimensions of part of the top electrode 123 are different, and the serpentine shape means that the orthographic projection of the top electrode 123 on the surface of the substrate 100 is arc-shaped, and the width dimensions of the top electrode 123 are basically equal.

[0076] In some embodiments, the silver content of the bottom electrode 113 is 50% to 90%, and the remaining material can be a base metal material such as doped nickel, aluminum, or copper. The material of the top electrode 123 can be a silver-coated copper paste, wherein the silver-coated copper particles have a size of 1 μm to 10 μm, and the curing temperature of the top electrode 123 paste is 100° C. to 350° C. Providing different materials for the bottom electrode 113 and the top electrode 123 can further reduce the cost of the electrode 103.

[0077] The disclosed embodiment sets the electrode 103 to include a non-common bottom electrode 113 and a top electrode 123, and contacts the doped conductive layer 101 only through the bottom electrode 113. Since the bottom electrodes 113 are arranged at intervals, the consumption of the electrode 103 slurry can be reduced, thereby reducing the cost of the solar cell. At the same time, the corresponding part of the bottom electrode 113 has a certain thickness. Therefore, the trough position of the top electrode 123 can be set to be opposite to the bottom electrode 113 to reduce the consumption of the top electrode 123 slurry. At the same time, the peak of the top electrode 123 is set to be opposite to the interval of the bottom electrode 113 to compensate for the transmission performance of the interval position, thereby reducing the cost of the electrode 103 while ensuring the transmission performance of the electrode 103.

[0078] An embodiment of the present disclosure also provides a photovoltaic module, which may include multiple solar cell panels as in the above embodiment. A photovoltaic module provided by an embodiment of the present disclosure will be described below in conjunction with the accompanying drawings. It should be noted that the parts that are the same or corresponding to the above can refer to the above embodiment and will not be repeated below.

[0079] refer to Figure 5 and Figure 6 ,in, Figure 5 A partial three-dimensional schematic diagram of a photovoltaic assembly provided by an embodiment of the present disclosure is shown. Figure 6 for Figure 5 A schematic partial cross-sectional view along a first cross-sectional direction BB1.

[0080] In some embodiments, a photovoltaic module includes: a cell string, the cell string including: a plurality of solar cells 40 formed by the method for forming the solar cells 40 in some or all of the above embodiments, or including the solar cells as described above; a welding ribbon 43, the welding ribbon 43 being electrically connected to at least two solar cells 40 to connect adjacent solar cells 40 in series.

[0081] The photovoltaic module further includes: a packaging film 41, which is used to cover the surface of the battery string.

[0082] The photovoltaic module further includes a cover plate 42 , which is used to cover the surface of the packaging film 41 away from the cell string.

[0083] In some embodiments, the encapsulation film 41 includes a first encapsulation layer and a second encapsulation layer, wherein the first encapsulation layer covers one of the front or back sides of the solar cell, and the second encapsulation layer covers the other of the front or back sides of the solar cell. Specifically, at least one of the first encapsulation layer or the second encapsulation layer can be an organic encapsulation film such as polyvinyl butyral (PVB) film, ethylene-vinyl acetate copolymer (EVA) film, polyethylene octene co-elastomer (POE) film or polyethylene terephthalate (PET) film, or at least one of the first encapsulation layer or the second encapsulation layer can also be an EP film, EPE film or PVP film. Among them, EP film refers to a co-extruded film composed of stacked EVA film and POE film, EPE film refers to a co-extruded film formed by stacking EVA film + POE film + EVA film in sequence, and PVP film refers to a co-extruded film formed by stacking POE film + EVA film + POE film. Co-extruded films can be prepared by sequentially extruding one or more raw materials onto another already manufactured film during the film processing process, or by bonding different types of already manufactured films together.

[0084] In some cases, there is a boundary line between the first encapsulation layer and the second encapsulation layer before lamination. After the lamination process, the photovoltaic module is formed and there is no longer the concept of the first encapsulation layer and the second encapsulation layer, that is, the first encapsulation layer and the second encapsulation layer have formed an integral encapsulation film 41.

[0085] In some embodiments, the cover plate 42 may be a light-transmitting cover plate such as a glass cover plate or a plastic cover plate. Specifically, the surface of the cover plate 42 facing the encapsulation film 41 may have a concave-convex surface or a velvet surface including multiple raised structures, thereby increasing the utilization of incident light. The cover plate 42 includes a first cover plate and a second cover plate. The first cover plate faces the first encapsulation layer, and the second cover plate faces the second encapsulation layer.

[0086] Those skilled in the art will appreciate that the above-described embodiments are specific examples for implementing the present disclosure, and in actual applications, various changes may be made to them in form and detail without departing from the spirit and scope of the embodiments of the present disclosure. Any person skilled in the art may make various changes and modifications without departing from the spirit and scope of the embodiments of the present disclosure. Therefore, the scope of protection of the embodiments of the present disclosure shall be based on the scope defined in the claims.

Claims

1. A solar cell, characterized in that: include: substrate; a doped conductive layer, wherein the doped conductive layer is located on one side of the substrate; a passivation layer, the passivation layer covering a surface of the doped conductive layer away from the substrate; Electrodes, the electrodes comprising: a plurality of bottom electrodes spaced apart along a first direction, the bottom electrodes being electrically connected to the doped conductive layer; A top electrode extending along a first direction, the top electrode covering the surface of the bottom electrode, and the surface of the top electrode away from the substrate is wavy and includes at least one crest and at least one trough, the trough of the top electrode is opposite to at least one bottom electrode, and the crest of the top electrode is opposite to the interval of at least the bottom electrode.

2. The solar cell according to claim 1, wherein: The top electrode covers the surface of the passivation layer, the bottom electrode is convex away from the top of the substrate, and the trough of the top electrode is opposite to the top of the bottom electrode.

3. The solar cell according to claim 1 or 2, characterized in that: A valley of the top electrode faces one of the bottom electrodes, and a peak of the top electrode faces a gap between the bottom electrodes.

4. The solar cell according to claim 1, wherein: Also includes: A second bottom electrode, the second bottom electrode is located between the bottom electrodes and connected to the bottom electrode, the bottom electrode covers the surface of the passivation layer, the bottom electrode is convex downward away from the top of the substrate, and the second bottom electrode is convex upward away from the top of the substrate.

5. The solar cell according to claim 4, characterized in that: A wave valley of the top electrode faces at least one of the bottom electrodes and at least one of the second bottom electrodes, and a wave peak of the top electrode faces at least one of the bottom electrodes and at least one of the second bottom electrodes.

6. The solar cell according to claim 5, characterized in that: A trough of the top electrode faces 2 to 10 of the bottom electrodes and 2 to 10 of the second bottom electrodes, and a peak of the top electrode faces 2 to 10 of the bottom electrodes and 2 to 10 of the second bottom electrodes.

7. The solar cell according to claim 4, characterized in that: A height difference between a top portion of the bottom electrode and a bottom portion of the second bottom electrode is 1 μm to 10 μm.

8. The solar cell according to claim 1, wherein: The interval between adjacent bottom electrodes is 0 μm to 200 μm.

9. The solar cell according to claim 1 or 8, characterized in that: Part of the bottom electrode is located in the doped conductive layer, and the depth of the bottom electrode in the doped conductive layer is 20 nm to 200 nm.

10. The solar cell according to claim 1, wherein: The thickness of the electrode is 5 μm to 25 μm.

11. The solar cell according to claim 1, wherein: The height difference between the crest and the trough of the top electrode is 4 μm to 20 μm.

12. The solar cell according to claim 1, wherein: In the second direction, the width of the bottom electrode is greater than or equal to the width of the top electrode, and the first direction and the second direction form an angle.

13. The solar cell according to claim 1, wherein: The orthographic projection of a portion of the top electrode on the surface of the substrate is arc-shaped.

14. A photovoltaic module, characterized in that: include: A battery string, the battery string comprising: a plurality of solar cells according to any one of claims 1 to 13; a welding ribbon, the welding ribbon being electrically connected to at least two solar cells to connect adjacent solar cells in series; A packaging film, the packaging film is used to cover the surface of the battery string; A cover plate is used to cover the surface of the packaging film away from the battery string.

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