Solar cell and photovoltaic module

Abstract

The embodiment of the present disclosure relates to the photovoltaic field, and provides a solar cell and a photovoltaic module, wherein the solar cell comprises a substrate, a doped conductive layer located on one side of the substrate, a passivation layer covering the surface of the doped conductive layer away from the substrate, and an electrode comprising a plurality of bottom electrodes arranged at intervals along a first direction, the bottom electrodes being electrically connected with the doped conductive layer, and 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 wave crest and at least one wave trough, the wave trough of the top electrode being opposite to at least one bottom electrode, and the wave crest of the top electrode being opposite to at least one bottom electrode at intervals. The cost can be reduced while ensuring the performance of the cell.

Description

Technical Field

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

[0002] A solar cell is a thin film of photovoltaic semiconductors that generates electricity directly from sunlight. Also known as a "solar chip" or "photovoltaic cell," it can instantly output voltage and, in the presence of a circuit, generate current when provided with sufficient illumination. In physics, this is called solar photovoltaic (PV), or simply photovoltaic. Summary of the Invention

[0003] This disclosure provides a solar cell and a photovoltaic module that can at least reduce the cost of the solar cell while avoiding affecting its transmission performance.

[0004] According to some embodiments of this disclosure, one aspect of this disclosure provides a solar cell, comprising: a substrate; a doped conductive layer located on one side of the substrate; a passivation layer covering the surface of the doped conductive layer away from the substrate; and electrodes comprising: a plurality of bottom electrodes spaced apart along a first direction, the bottom electrodes being electrically connected to the doped conductive layer; and a top electrode extending along the first direction, the top electrode covering the surface of the bottom electrodes, and the surface of the top electrode away from the substrate being wavy, including at least one peak and at least one trough, the trough of the top electrode being directly opposite at least one bottom electrode, and the peak of the top electrode being directly opposite the interval of at least one bottom electrode.

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

[0006] In some embodiments, a trough of the top electrode is directly opposite a bottom electrode, and a peak of the top electrode is directly opposite a gap in the bottom electrode.

[0007] In some embodiments, the system further includes: a second bottom electrode located between and connected to the bottom electrodes, the bottom electrodes covering the surface of the passivation layer, the top of the bottom electrodes away from the substrate being convex downwards, and the top of the second bottom electrode away from the substrate being convex upwards.

[0008] In some embodiments, a trough of the top electrode is directly opposite to at least one of the bottom electrodes and at least one of the second bottom electrodes, and a peak of the top electrode is directly opposite to 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 is directly opposite to 2 to 10 of the bottom electrodes and 2 to 10 of the second bottom electrodes, and a peak of the top electrode is directly opposite to 2 to 10 of the bottom electrodes and 2 to 10 of the second bottom electrodes.

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

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

[0012] In some embodiments, a portion of the bottom electrode is located within the doped conductive layer, and the depth of the bottom electrode within 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 peak and 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 forms an angle with the second direction.

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

[0017] According to some embodiments of this disclosure, another aspect of this disclosure provides a photovoltaic module, including: a battery string, the battery string including: a plurality of solar cells as described above; a solder ribbon electrically connected to at least two solar cells to connect adjacent solar cells in series; an encapsulating film for covering the surface of the battery string; and a cover plate for covering the surface of the encapsulating film away from the battery string.

[0018] The technical solution provided by the embodiments of this disclosure has at least the following advantages: the electrode includes a non-coherent bottom electrode and a top electrode, and the bottom electrode is in contact with the doped conductive layer only. Since the bottom electrodes are spaced apart, the consumption of electrode paste can be reduced, 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 be directly opposite the bottom electrode to reduce the consumption of top electrode paste. Meanwhile, the peak of the top electrode is set to be directly opposite the gap of the bottom electrode to compensate for the transmission performance at the gap position, thereby reducing the electrode cost while ensuring the transmission performance of the electrode. Attached Figure Description

[0019] 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.

[0020] Figure 1 A top view of a solar cell provided according to an embodiment of this disclosure;

[0021] Figure 2 A cross-sectional view of a solar cell provided in an embodiment of this disclosure;

[0022] Figure 3 A cross-sectional view of a second type of solar cell provided in an embodiment of this disclosure;

[0023] Figure 4 A cross-sectional view of a third type of solar cell provided in an embodiment of this disclosure;

[0024] Figure 5 This is a partial perspective view of a photovoltaic module provided in an embodiment of the present disclosure;

[0025] Figure 6 This is a cross-sectional view of a photovoltaic module provided in an embodiment of the present disclosure.

[0026] Explanation of reference numerals in the attached figures:

[0027] 100, Substrate; 101, Doped conductive layer; 102, Passivation layer; 103, Electrode; 113, Bottom electrode; 123, Top electrode; 104, Tunneling layer; 133, Second bottom electrode.

[0028] 40. Solar cell; 41. Encapsulating film; 42. Cover plate; 43. Solder strip. Detailed Implementation

[0029] Currently, the electrodes of solar cells are usually screen-printed, and since the electrodes of the entire solar cell are made of silver paste, the silver consumption of each cell is relatively large, so it is necessary to reduce the use of paste in solar cells.

[0030] The technical solution provided by the embodiments of this disclosure has at least the following advantages: the electrode includes a non-coherent bottom electrode and a top electrode, and the bottom electrode is in contact with the doped conductive layer only. Since the bottom electrodes are spaced apart, the consumption of electrode paste can be reduced, 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 be directly opposite the bottom electrode to reduce the consumption of top electrode paste. Meanwhile, the peak of the top electrode is set to be directly opposite the gap of the bottom electrode to compensate for the transmission performance at the gap position, thereby reducing the electrode cost while ensuring the transmission performance of the electrode.

[0031] In the description of the embodiments of this disclosure, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary or secondary relationship of the indicated technical features. In the description of the embodiments of this disclosure, "a plurality of" means two or more, unless otherwise explicitly defined.

[0032] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this disclosure. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0033] In the description of the embodiments of this disclosure, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent three cases: A exists, A and B exist simultaneously, and B exists. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0034] In the description of embodiments of this disclosure, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0035] In the description of the embodiments of this disclosure, the technical terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this disclosure and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this disclosure.

[0036] In the description of the embodiments of this disclosure, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this disclosure according to the specific circumstances.

[0037] In the accompanying drawings corresponding to the embodiments of this disclosure, the thickness and area of ​​the layers are enlarged for better understanding and ease of description. When describing a component (such as a layer, film, region, or substrate) on or on the surface of another component, the component may be "directly" located on the surface of the other component, or there may be a third component between the two components. Conversely, when describing a component on the surface of another component, or when another component is formed or disposed on the surface of a component, it indicates that there is no third component between the two components. Furthermore, when describing a component as being "generally" formed on another component, it means that the component is not formed on the entire surface (or front surface) of the other component, nor is it formed on a portion of the edge of the entire surface.

[0038] In the description of embodiments of this disclosure, when a component "includes" another component, other components are not excluded unless otherwise stated, and may be further included. Furthermore, when a component such as a layer, film, region, or plate is referred to as being "on / located" on another component, it can be "directly" on the other component (i.e., located on the surface of the other component with no other components between them), or another component may be present therein. Additionally, when a component such as a layer, film, region, or plate is "directly located" on another component, or when a component such as a layer, film, region, or plate is located on the surface of another component, it indicates that no other components are located therein.

[0039] The terminology used in the description of the various embodiments herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used in the description and claims of the various embodiments described, the term "component" is also intended to include the plural form unless the context clearly indicates otherwise. Components include layers, films, regions, or plates, etc.

[0040] 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.

[0041] refer to Figures 1 to 4 , Figure 1 A top view of a solar cell provided according to an embodiment of this disclosure; Figure 2 Provided for an embodiment of this disclosure Figure 1 A cross-sectional view of a solar cell in the MM1 direction; Figure 3 Provided for an embodiment of this disclosure Figure 1 Cross-sectional view of the second type of solar cell in the MM1 direction; Figure 4 Provided for an embodiment of this disclosure Figure 1 Cross-sectional view of the third type of solar cell in the MM1 direction.

[0042] In some embodiments, the solar cell may include a substrate 100.

[0043] The solar cell may also include a doped conductive layer 101, which is located on one side of the substrate 100.

[0044] The solar cell may also include a passivation layer 102, which covers the surface of the doped conductive layer 101 away from the substrate 100.

[0045] 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 electrodes 113, and the surface of the top electrode 123 away from the substrate 100 being wavy, including at least one peak and at least one trough, the trough of the top electrode 123 being directly opposite to at least one bottom electrode 113, and the peak of the top electrode 123 being directly opposite to the spacing of at least one bottom electrode 113.

[0046] The technical solution provided by the embodiments of this disclosure has at least the following advantages: the electrode 103 includes a non-coherent bottom electrode 113 and a top electrode 123, and the bottom electrode 113 is in contact with the doped conductive layer 101. Since the bottom electrodes 113 are spaced apart, the consumption of electrode paste 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 face the bottom electrode 113 to reduce the consumption of top electrode paste. At the same time, the peak of the top electrode 123 is set to face the gap of the bottom electrode 113 to compensate for the transmission performance at the gap position. Thus, the transmission performance of the electrode 103 is guaranteed while reducing the cost of the electrode 103.

[0047] In some embodiments, the solar cell can 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 cell), a HIT / HJT cell (Heterojunction Technology cell), or a BC cell (Back Contact cell). In other embodiments, the solar cell can also be a tandem cell comprising any of the above-mentioned cells (where the top cell is a perovskite cell and the bottom cell is any one of the above-mentioned cells), or a half-cell of any of the above-mentioned cells, etc.

[0048] In some embodiments, the battery cell is a single-sided battery, in which case the front side of the substrate 100 can serve as a light-receiving surface to receive incident light, and the back side serves as a backlighting surface. In some embodiments, the battery cell is a double-sided battery, in which case both the front and back sides of the substrate 100 can serve as light-receiving surfaces and can be used to receive incident light. It is understood that the backlighting surface referred to in the embodiments of this disclosure can also receive incident light, but the degree of reception of incident light is weaker than that of the light-receiving surface, and therefore it is defined as a backlighting surface.

[0049] 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 textured surface on at least one of the front or back surfaces of the substrate 100. This can enhance the absorption and utilization efficiency of incident light on the front and back surfaces of the substrate 100. In some embodiments, the textured surface can be a pyramid textured surface. As a common textured surface, pyramid textured surface not only reduces the reflectivity of the substrate 100 surface but also forms light traps, enhancing the absorption effect of the substrate 100 on incident light and improving the photoelectric conversion efficiency of the solar cell.

[0050] In some embodiments, the solar cell may further include a tunneling layer 104 located between the substrate 100 and the doped conductive layer 101, such that the tunneling layer 104 has a chemical passivation effect on the back side of the substrate 100, specifically by reducing the defect state density on the back side of the substrate 100 by saturating the dangling bonds 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.

[0051] 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.

[0052] The material of the doped conductive layer 101 may include at least one of amorphous silicon, polycrystalline silicon, or silicon carbide.

[0053] The doped conductive layer 101 can be doped with dopants of the same type as the substrate 100. For example, if the dopants in the substrate 100 are P-type, then the dopants in the doped conductive layer 101 can also be P-type; if the dopants in the substrate 100 are N-type, then the dopants in the doped conductive layer 101 can also be N-type. The doped conductive layer 101 can also be doped with dopants of a different type than the substrate 100. For example, if the dopants in the substrate 100 are P-type, then the dopants in the doped conductive layer 101 can also be N-type; if the dopants in the substrate 100 are N-type, then the dopants in the doped conductive layer 101 can also be P-type.

[0054] In some embodiments, the doped conductive layer 101 may be located on one side surface of the substrate 100, and in other embodiments, the doped conductive layer 101 may be located within the substrate 100.

[0055] The solar cell may also 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 provide good passivation for the back side of the substrate 100, for example, it can effectively chemically 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.

[0056] The material of the passivation layer 102 can be one of silicon oxide, aluminum oxide, silicon nitride, or silicon oxynitride.

[0057] 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.

[0058] In some embodiments, the top electrode 123 covers the surface of the passivation layer 102, the bottom electrode 113 is convex at the top away from the substrate 100, and the trough of the top electrode 123 is directly opposite the top of the bottom electrode 113. The top electrode 123 covers the surface of the passivation layer 102, meaning that the electrode 103 is only electrically connected to the doped conductive layer 101 through the bottom electrode 113. The top of the bottom electrode 113 away from the substrate 100 is convex, meaning that the bottom electrode 113 protrudes in a direction away from the substrate 100. The trough of the top electrode 123 is directly opposite the top of the substrate 100, meaning that 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 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 amount of paste used for the top electrode 123, which can also reduce the cost of the solar cell.

[0059] In some embodiments, a trough of the top electrode 123 is directly opposite a bottom electrode 113, and a peak of the top electrode 123 is directly opposite a gap in the bottom electrode 113. For the top electrode 123, the portion corresponding to the trough represents the part with poor transmission capability. Therefore, by having the trough directly opposite the bottom electrode 113, the bottom electrode 113 compensates for the poor transmission capability of the top electrode 123. The peak of the top electrode 123 represents the part with good transmission capability. By having the top electrode 123 and the bottom electrode 113 directly opposite each other, and since the gap does not have a bottom electrode 113, using the part with good transmission capability opposite the gap can balance the overall transmission capability of the electrode 103. Setting a trough directly opposite a bottom electrode 113 and a peak directly opposite a gap can reduce the cost of the solar cell while avoiding affecting its performance.

[0060] It should be noted that "aligned" here can mean that the trough and the bottom electrode 113 are completely aligned, or it can mean that the trough and the bottom electrode 113 are partially offset. Within the allowable range of offset, it can also be regarded as the trough and the bottom electrode 113 being aligned. The allowable range of offset here means that, taking the surface morphology of the top electrode 123 away from the substrate 100 as a sinusoidal morphology, the size of the offset between the trough and the bottom electrode 113 is less than or equal to 1 / 8 of a sinusoidal period, which can be regarded as the trough and the bottom electrode 113 being aligned.

[0061] In some embodiments, the bottom electrode 113 is convex at the top away from the substrate 100, 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 the gap of the bottom electrode 113. Alternatively, the lowest point of the trough is directly opposite to the highest point of the bottom electrode 113, and the highest point of the top electrode 123 is directly opposite to the center point of the gap of the bottom electrodes 113.

[0062] In some embodiments, the system may further include a second bottom electrode 133, which is located between and connected to the bottom electrodes 113. The bottom electrodes 113 cover the surface of the passivation layer 102. The top of the bottom electrodes 113 away from the substrate 100 is convex downwards, and the top of the second bottom electrode 133 away from the substrate 100 is convex upwards. That is, the top electrode 123 is spaced apart from the passivation layer 102, and the bottom electrodes 113 and the second bottom electrode 133 together form a wave-shaped structure. On the one hand, the second bottom electrode 133 can improve the reliability of transmission between the bottom electrodes 113 and the top electrode 123. In the event of an abnormal transmission between any bottom electrode 113 and the top electrode 123, the abnormal transmission path can be reconnected through the second bottom electrode 133. On the other hand, the second bottom electrode 133 can also reduce the contact resistance between the bottom electrodes 113 and the top electrode 123. By increasing the contact area, the transmission loss of the solar cell carriers can be reduced.

[0063] In some embodiments, the second bottom electrode 133 and the bottom electrode 113 can be an integral 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.

[0064] It is understood that the bottom electrode 113 is convex downwards at the top away from the substrate 100, and the second bottom electrode 133 is convex upwards at the top away from the substrate 100. That is, the bottom electrode 113 forms a peak, the second bottom electrode 133 forms a trough, and the peak of the top electrode 123 is aligned with the bottom electrode 113, that is, the peak of the top electrode 123 is aligned with the second bottom electrode 133.

[0065] Furthermore, when a trough of the top electrode 123 is directly opposite a bottom electrode 113, and a peak of the top electrode 123 is directly opposite a second bottom electrode 133, that is, when the trough of the top electrode 123 is directly opposite the peak of the bottom electrode 113, and the peak of the top electrode 123 is directly opposite the trough of the second bottom electrode 133, in other words, when the bottom electrode 113 and the second bottom electrode 133 are regarded as a whole, the wavy peak of the top electrode 123 is interlocked with the overall trough of the bottom electrode 113 and the second bottom electrode 133, and the wavy trough of the top electrode 123 is interlocked with the overall peak of the bottom electrode 113 and the second bottom electrode 133. Thus, the part corresponding to the trough is the part of the top electrode 123 with poor transmission capability. Therefore, by aligning the trough with the bottom electrode 113, the bottom electrode 113 can compensate for the transmission capability of the top electrode 123. The peak of the top electrode 123 is the part of the top electrode 123 with good transmission capability. 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 one trough to be aligned with one bottom electrode 113 and one peak to be aligned with one second bottom electrode 133, the cost of the solar cell can be reduced while avoiding affecting the performance of the solar cell.

[0066] In some embodiments, a trough of the top electrode 123 is directly 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 directly opposite to at least one bottom electrode 113 and at least one second bottom electrode 133. That is, the upwardly convex portion of the top electrode 123 is directly opposite to at least one bottom electrode 113 and at least one second bottom electrode 133, and the downwardly convex portion of the top electrode 123 is directly opposite to 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 trough of the top electrode 123 and the peak of the whole bottom electrode 113 and the second bottom electrode 133 are not in a one-to-one correspondence, but rather the trough of the top electrode 123 corresponds to at least one period of the whole bottom electrode 113 and the second bottom electrode 133, and the peak of the top electrode 123 corresponds to at least one period of the whole bottom electrode 113 and the second bottom electrode 133. In this way, the transmission performance of electrode 103 can be guaranteed while reducing the amount of paste used in electrode 103. Moreover, setting a trough of top electrode 123 to be directly opposite to at least one bottom electrode 113 and at least one second bottom electrode 133, and setting a peak of top electrode 123 to be directly opposite to at least one bottom electrode 113 and at least one second bottom electrode 133, can also reduce the alignment difficulty in forming solar cells, thereby reducing the manufacturing difficulty of solar cells.

[0067] It should be noted that the 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 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. One cycle between the bottom electrode 113 and the second bottom electrode 133 refers to the cycle formed by the peak of the bottom electrode 113 and the trough of the second bottom electrode 133. Taking the sine curve as an example, the sine curve's overall shape between the bottom electrode 113 and the second bottom electrode 133 corresponds to one cycle of the sine curve between the bottom electrode 113 and the second bottom electrode 133.

[0068] In some embodiments, the number of times each cycle of the top electrode 123 is directly opposite to the bottom electrode 113 and the second bottom electrode 133 may be different. For example, in one cycle of the top electrode 123, the trough of the top electrode 123 may be directly opposite to one bottom electrode 113 and one second bottom electrode 133, and the peak of the top electrode 123 may be directly opposite to one bottom electrode 113 and one second bottom electrode 133. In another cycle of the top electrode 123, the trough of the top electrode 123 may be directly opposite to two bottom electrodes 113 and two second bottom electrodes 133, and the peak of the top electrode 123 may be directly opposite to two bottom electrodes 113 and two second bottom electrodes 133.

[0069] In some embodiments, the number of peaks of the top electrode 123 that are directly opposite the bottom electrode 113 and the second bottom electrode 133 in each cycle is different from the number of troughs that are directly opposite the bottom electrode 113 and the second bottom electrode 133. For example, in the same cycle, the peak of the top electrode 123 may be directly opposite one bottom electrode 113 and one second bottom electrode 133, and the trough of the top electrode 123 may be directly opposite two bottom electrodes 113 and two second bottom electrodes 133.

[0070] In some embodiments, the number of troughs of the top electrode 123 that are directly opposite to the bottom electrode 113 and the second bottom electrode 133 may not be an integer. For example, the peaks of the top electrode 123 may be directly opposite to 1.5 bottom electrodes 113 and 1.5 second bottom electrodes 133, and the troughs of the top electrode 123 may be directly opposite to 1.5 bottom electrodes 113 and 1.5 second bottom electrodes 133.

[0071] In some embodiments, a trough of the top electrode 123 is directly opposite to 2 to 10 bottom electrodes 113 and 2 to 10 second bottom electrodes 133, and a peak of the top electrode 123 is directly opposite to 2 to 10 bottom electrodes 113 and 2 to 10 second bottom electrodes 133. For example, a trough of the top electrode 123 may be directly opposite to 2, 3, 4, 5, 6, 7, 8, 9, or 10 bottom electrodes 113, and the same trough may also be directly opposite to 2, 3, 4, 5, 6, 7, 8, 9, or 10 second bottom electrodes 133.

[0072] The greater the number of troughs of the top electrode 123 that are directly opposite to the bottom electrode 113 and the second bottom electrode 133, the larger the span of the peaks and troughs of the top electrode 123, which makes it more difficult to form troughs. Similarly, the greater the number of peaks of the top electrode 123 that are directly opposite to the bottom electrode 113 and the second bottom electrode 133, the more difficult it is to form peaks. By controlling that one trough is directly opposite to 2 to 10 bottom electrodes 113 and 2 to 10 second bottom electrodes 133, and one peak is directly opposite to 2 to 10 bottom electrodes 113 and 2 to 10 second bottom electrodes 133, the required slurry for the top electrode 123 can be reduced while the formation difficulty of the top electrode 123 can be reduced.

[0073] 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 avoids an excessively large height difference between the bottom electrode 113 and the second bottom electrode 133, preventing the occurrence of discontinuities or gaps between them, 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 their cost, thereby reducing the cost of solar cells.

[0074] 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 morphological curve of the bottom electrode 113 and the second bottom electrode 133.

[0075] 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, etc. 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 the carrier transport between the electrode 103 and the doped conductive layer 101. Therefore, it is necessary to control the spacing between adjacent bottom electrodes 113 to be less than 200 μm.

[0076] 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, for example, 50 nm, 70 nm, 100 nm, 120 nm, 150 nm, 180 nm, or 200 nm, etc. For the electrode 103, since only the bottom electrode 113 is electrically connected to the doped conductive layer 101, and the bottom electrodes 113 are spaced apart, it 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. However, if the bottom electrode 113 is located too deep within the doped conductive layer 101, it may cause metal ions from the bottom electrode 113 to diffuse into the substrate 100, affecting the reliability of the solar cell.

[0077] In some embodiments, the thickness of electrode 103 is 5 μm to 25 μm, for example, 8 μm, 10 μm, 12 μm, 15 μm, 20 μm, or 25 μm, etc. The thickness of electrode 103 can refer to the sum of the thicknesses of bottom electrode 113 and top electrode 123, or it can refer to the thickness of top electrode 123 corresponding to the interval position. By controlling the thickness of electrode 103, the paste required to form electrode 103 can be further controlled, thereby further controlling the cost of solar cell.

[0078] In some embodiments, the height difference between the peak and trough of the top electrode 123 is 4μm to 20μm, for example, 6μm, 8μm, 10μm, 12μm, 15μm, 18μm, or 20μm, etc. The larger the height difference between the peak and trough of the top electrode 123, the more paste is saved by the top electrode 123, and the more the cost of the solar cell is reduced. At the same time, the larger the height difference between the peak and trough of the top electrode 123, the more likely it is to cause the top electrode 123 to have discontinuities or reliability reduction due to abrupt changes in height. Therefore, setting the height difference between the peak and trough of the top electrode 123 to 4μm to 20μm improves the reliability of the top electrode 123 while controlling its cost.

[0079] 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 forms an angle with the second direction. Setting the width of the bottom electrode 113 to be greater than or equal to the width of the top electrode 123 can facilitate the alignment between the top electrode 123 and the electrode 103, reduce the manufacturing difficulty of the solar cell, and on the other hand, can also improve the reliability of the contact between the bottom electrode 113 and the top electrode 123.

[0080] In some embodiments, the orthographic projection of a portion of the top electrode 123 onto the surface of the substrate 100 is arc-shaped. Setting the orthographic projection of the top electrode 123 onto the surface of the substrate 100 to be arc-shaped 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, and thus improving the reliability of the solar cell.

[0081] In some embodiments, the orthographic projection of the top electrode 123 onto the surface of the substrate 100 can be gourd-shaped or serpentine. The gourd-shaped shape means that some of the top electrodes 123 have different widths, while the serpentine shape means that the orthographic projection of the top electrode 123 onto the surface of the substrate 100 is arc-shaped, and the widths of the top electrodes 123 are substantially equal.

[0082] In some embodiments, the silver content in the bottom electrode 113 is 50% to 90%, and the remaining material can be base metal materials such as nickel, aluminum, or copper. The material of the top electrode 123 can be silver-coated copper paste, wherein the size of the silver-coated copper particles is 1 μm to 10 μm, and the curing temperature of the top electrode 123 paste is 100°C to 350°C. Using different materials for the bottom electrode 113 and the top electrode 123 can further reduce the cost of the electrode 103.

[0083] In this embodiment, the electrode 103 includes a non-coherent bottom electrode 113 and a top electrode 123. The bottom electrode 113 is in contact with the doped conductive layer 101. Since the bottom electrodes 113 are spaced apart, the consumption of electrode paste 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 directly opposite the bottom electrode 113 to reduce the consumption of top electrode paste. Meanwhile, the peak of the top electrode 123 is set to be directly opposite the spacing of the bottom electrode 113 to compensate for the transmission performance at the spacing position. Thus, the transmission performance of the electrode 103 is guaranteed while reducing the cost of the electrode 103.

[0084] This disclosure also provides a photovoltaic module, which may include a plurality of solar cells as described in the above embodiments. The following will describe a photovoltaic module provided by an embodiment of this disclosure with reference to the accompanying drawings. It should be noted that the same or corresponding parts as described above can be referred to the above embodiments, and will not be repeated hereafter.

[0085] refer to Figure 5 and Figure 6 ,in, Figure 5 This is a partial three-dimensional schematic diagram of a photovoltaic module provided in an embodiment of the present disclosure. Figure 6 for Figure 5 A partial cross-sectional schematic diagram along the first section direction BB1.

[0086] In some embodiments, the photovoltaic module includes: a battery string, which includes: a plurality of solar cells 40 formed by the method of forming solar cells 40 as described in some or all of the above embodiments, or includes solar cells as described above; and a solder ribbon 43 electrically connected to at least two solar cells 40 to connect adjacent solar cells 40 in series.

[0087] The photovoltaic module also includes an encapsulating film 41, which is used to cover the surface of the cell string.

[0088] The photovoltaic module also includes a cover plate 42, which is used to cover the surface of the encapsulating film 41 away from the cell string.

[0089] In some embodiments, the encapsulating film 41 includes a first encapsulating layer and a second encapsulating layer. The first encapsulating layer covers one of the front or back sides of the solar cell, and the second encapsulating layer covers the other of the front or back sides of the solar cell. Specifically, at least one of the first or second encapsulating layer can be an organic encapsulating film such as polyvinyl butyral (PVB) film, ethylene-vinyl acetate copolymer (EVA) film, polyvinyl octene elastomer (POE) film, or polyethylene terephthalate (PET) film. Alternatively, at least one of the first or second encapsulating layer can also be an EP film, an EPE film, or a PVP film. Here, EP film refers to a co-extruded film composed of stacked EVA film and POE film; EPE film refers to a co-extruded film formed by sequentially stacking EVA film + POE film + EVA film; and PVP film refers to a co-extruded film formed by stacking POE film + EVA film + POE film. Co-extruded films can be prepared by sequentially extruding one or more raw materials onto another pre-made film during the film processing, or by bonding different types of pre-made films together.

[0090] In some cases, the first encapsulation layer and the second encapsulation layer still have a boundary line before lamination. After lamination, the photovoltaic module will no longer have the concept of a first encapsulation layer and a second encapsulation layer. That is, the first encapsulation layer and the second encapsulation layer have formed an integral encapsulation film 41.

[0091] In some embodiments, the cover plate 42 can be a glass cover plate, a plastic cover plate, or other cover plate with light-transmitting function. Specifically, the surface of the cover plate 42 facing the encapsulating film 41 can be an uneven surface or a textured surface containing multiple raised structures, thereby increasing the utilization rate of incident light. The cover plate 42 includes a first cover plate and a second cover plate, the first cover plate being opposite to the first encapsulation layer, and the second cover plate being opposite to the second encapsulation layer.

[0092] 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: Base; A doped conductive layer is located on one side of the substrate; A passivation layer that covers the surface of the doped conductive layer away from the substrate; The electrode includes: a plurality of bottom electrodes spaced apart along a first direction, the bottom electrodes being electrically connected to the doped conductive layer; and a top electrode extending along the first direction, the top electrode covering the surface of the bottom electrodes, and the surface of the top electrode away from the substrate being wavy, including at least one peak and at least one trough, the trough of the top electrode being directly opposite at least one bottom electrode, and the peak of the top electrode being directly opposite the interval of at least the bottom electrodes; It also includes: a second bottom electrode, which is located between the bottom electrodes and connected to the bottom electrodes. The second bottom electrode covers the surface of the passivation layer. The top of the bottom electrodes away from the substrate is convex downwards, and the top of the second bottom electrode away from the substrate is convex upwards. In the second direction, the width of the bottom electrode is greater than the width of the top electrode, and the first direction forms an angle with the second direction.

2. The solar cell according to claim 1, characterized in that, The top electrode covers the surface of the passivation layer, the bottom electrode is convex at the top away from the substrate, and the trough of the top electrode is directly opposite the top of the bottom electrode.

3. The solar cell according to claim 1 or 2, characterized in that, A trough of the top electrode is directly opposite a bottom electrode, and a peak of the top electrode is directly opposite a gap in the bottom electrode.

4. The solar cell according to claim 1, characterized in that, A trough of the top electrode is directly opposite to at least one of the bottom electrodes and at least one of the second bottom electrodes, and a peak of the top electrode is directly opposite to at least one of the bottom electrodes and at least one of the second bottom electrodes.

5. The solar cell according to claim 1, characterized in that, A trough of the top electrode is directly opposite 2 to 10 of the bottom electrodes and 2 to 10 of the second bottom electrodes, and a peak of the top electrode is directly opposite 2 to 10 of the bottom electrodes and 2 to 10 of the second bottom electrodes.

6. The solar cell according to claim 1, characterized in that, The height difference between the top of the bottom electrode and the bottom of the second bottom electrode is 1 μm to 10 μm.

7. The solar cell according to claim 1, characterized in that, The spacing between adjacent bottom electrodes is less than or equal to 200 μm.

8. The solar cell according to claim 1 or 7, characterized in that, Part of the bottom electrode is located within the doped conductive layer, and the depth of the bottom electrode within the doped conductive layer is 20 nm to 200 nm.

9. The solar cell according to claim 1, characterized in that, The thickness of the electrode is 5μm to 25μm.

10. The solar cell according to claim 1, characterized in that, The height difference between the peak and trough of the top electrode is 4μm to 20μm.

11. The solar cell according to claim 1, characterized in that, The orthographic projection of a portion of the top electrode onto the substrate surface is arc-shaped.

12. A photovoltaic module, characterized in that, include: A battery string, the battery string comprising: a plurality of solar cells as described in any one of claims 1 to 11; a solder ribbon electrically connected to at least two solar cells to connect adjacent solar cells in series; An encapsulating film, the encapsulating film being used to cover the surface of the battery string; A cover plate for covering the surface of the encapsulating film away from the battery string.

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