Solar cells and photovoltaic modules

Abstract

This disclosure relates to the photovoltaic field, providing a solar cell and a photovoltaic module. The solar cell includes a substrate, a plurality of first grid lines, and a plurality of second grid lines. The substrate includes a central region and edge regions located on opposite sides of the central region in a first direction. Along a second direction, the width of the first grid lines located on the edge regions is greater than the width of the first grid lines located in the central region. The second grid lines include a main body and end portions located at opposite ends of the main body in a second direction. Along the first direction, the width of the end portions is greater than the width of the main body. The main body includes alternating first and second segments along the second direction. The projection of the first segment onto the thickness direction of the substrate is wavy, and the projection of the second segment onto the thickness direction of the substrate is straight. This disclosure can at least improve the connection reliability between the second grid lines and the solder strip, improve the performance of the solar cell, and save manufacturing costs.

Description

Technical Field

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

[0002] As fossil fuels are gradually depleted, solar energy is becoming increasingly widely used as a new energy alternative. A solar cell is a device that converts sunlight into electrical energy. Solar cells utilize the photovoltaic principle to generate charge carriers, which are then extracted using electrodes, thus facilitating the efficient use of electrical energy.

[0003] Solar cells are equipped with a main grid for collecting charge carriers. The main grid contacts the solder strip to transfer the collected charge carriers to the solder strip. However, the design of the main grid structure in related technologies has certain problems, resulting in low reliability of the connection between the main grid and the solder strip. Summary of the Invention

[0004] This disclosure provides a solar cell and a photovoltaic module that can improve the connection reliability between the second grid line and the solder strip, improve the performance of the solar cell, and save the manufacturing cost of the solar cell.

[0005] According to some embodiments of this disclosure, one aspect of this disclosure provides a solar cell, the solar cell comprising: a substrate, the substrate including a central region and edge regions located on opposite sides of the central region in a first direction; a plurality of first grid lines, the plurality of first grid lines being spaced apart on the substrate along a second direction, wherein, along the second direction, the width of the first grid lines located on the edge regions is greater than the width of the second grid lines located on the central region; a plurality of second grid lines, the plurality of second grid lines being spaced apart on the substrate along the first direction and electrically connected to the first grid lines, the second grid lines including a main body portion and end portions located at opposite ends of the main body portion in the second direction, wherein, along the first direction, the width of the end portions is greater than the width of the main body portion, the main body portion including a first segment and a second segment alternately distributed along the second direction, wherein the projection of the first segment in the thickness direction of the substrate is wavy, and the projection of the second segment in the thickness direction of the substrate is straight.

[0006] In some embodiments, the first segment is electrically connected to at least two of the first gate lines, and the second segment is electrically connected to at least two of the first gate lines.

[0007] In some embodiments, the first grid line connected to the first segment is located between the crests and troughs of the wave shape.

[0008] In some embodiments, along the second direction, the length of the first segment is equal to the length of the second segment, and the width of the first segment is equal to the width of the second segment, and the number of first gate lines connected to the first segment is greater than the number of first gate lines connected to the second segment.

[0009] In some embodiments, along the second direction, the ratio of the length of the second segment to the length of the first segment is 2 / 3 to 6.

[0010] In some embodiments, along the second direction, the length of the first segment is 0.5mm to 1.5mm, and the length of the second segment is 1mm to 3mm.

[0011] In some embodiments, the amplitude of the wave shape is 30μm to 60μm, and the wavelength of the wave shape is 150μm to 300μm.

[0012] In some embodiments, the width of the first gate line located on the edge region along the second direction is 38μm~48μm, and the width of the first gate line located on the middle region along the second direction is 28μm~38μm.

[0013] In some embodiments, the first grid line includes a first portion and a second portion disposed along the first direction, wherein the width of the first portion gradually increases along the second direction in a direction away from the second portion; and the width of the second portion gradually increases along the second direction in a direction away from the first portion.

[0014] In some embodiments, the length of the end along the second direction is 0.8 mm to 1.5 mm.

[0015] In some embodiments, in the direction from the main body to the end portion, the width of the end portion gradually increases along a first direction.

[0016] In some embodiments, the width of the edge of the end portion away from the main body portion along the first direction is 45μm to 55μm, and the width of the main body portion along the first direction is 35μm to 45μm.

[0017] In some embodiments, the solar cell further includes a welding portion electrically connected to the second grid line, and a plurality of welding portions electrically connected to the same second grid line are located on the same straight line.

[0018] In some embodiments, the length of the welded portion along the first direction is greater than the length of the welded portion along the second direction.

[0019] According to some embodiments of this disclosure, another aspect of this disclosure also provides a photovoltaic module, the photovoltaic module comprising: a battery string, formed by connecting a plurality of solar cells as described in any of the above embodiments; an encapsulating film for covering the surface of the battery string; and a cover plate for covering the surface of the encapsulating film opposite to the battery string.

[0020] The technical solutions provided in this disclosure have at least the following advantages:

[0021] In the solar cell technical solution provided in this disclosure, the main body of the second grid line includes alternating first and second segments. The projection of the first segment in the thickness direction of the substrate is wavy, which allows the solder ribbon to contact the wavy first segment even if there is a slight offset in the first direction when welding the solder ribbon to the second grid line. This results in a larger contact area between the solder ribbon and the first segment compared to the contact area between the straight second grid line and the solder ribbon, thereby improving the connection reliability between the second grid line and the solder ribbon. The projection of the first segment in the thickness direction of the substrate is straight, which helps to save material for the second grid line, thereby reducing the manufacturing cost of the solar cell.

[0022] Along the first direction, the width of the end portion is greater than the width of the main body. That is, the end portion of the second grid line has a larger width along the first direction, allowing the solder ribbon to maintain electrical contact with the end portion even with slight misalignment in the first direction. This also helps improve the connection reliability between the second grid line and the solder ribbon. Furthermore, the wider width at the end portion reduces the end resistance, preventing heat concentration due to excessive end resistance and thus avoiding impact on the performance of the solar cell, thereby also contributing to improved solar cell performance.

[0023] The width of the first grid line located on the edge region is greater than the width of the first grid line located on the middle region. That is, the width of the first grid line located on the edge region is larger, which can reduce the risk of grid breakage of the first grid line on the edge region, and can also improve the efficiency of the first grid line in collecting charge carriers on the edge region, thereby also helping to improve the performance of the solar cell. Attached Figure Description

[0024] 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.

[0025] Figure 1A schematic diagram of a solar cell provided in an embodiment of this disclosure;

[0026] Figure 2 A partial cross-sectional view of a solar cell provided in an embodiment of this disclosure;

[0027] Figure 3 A schematic diagram of a structure of the first grid line in a solar cell provided in an embodiment of this disclosure;

[0028] Figure 4 This is a schematic diagram of the end structure of a solar cell provided in an embodiment of the present disclosure;

[0029] Figure 5 A partial structural schematic diagram of the first grid line and the first segment in a solar cell provided in an embodiment of this disclosure;

[0030] Figure 6 Another structural schematic diagram of a solar cell provided in an embodiment of this disclosure;

[0031] Figure 7 This is a schematic diagram of a photovoltaic module provided in an embodiment of the present disclosure.

[0032] Explanation of reference numerals in the attached figures:

[0033] 10. Substrate; 101. Middle area; 102. Edge area; 103. First surface; 104. Second surface; 11. First grid line; 111. First part; 112. Second part; 12. Second grid line; 121. Main body; 1211. First segment; 1212. Second segment; 122. End; 13. Welding part; 20. Solar cell; 21. Encapsulating film; 22. Cover plate; 23. Solder strip. Detailed Implementation

[0034] In related technologies, solar cells include a substrate and multiple main grids arranged along a first direction. The projection of the main grids onto the thickness direction of the substrate is typically set to a straight line, i.e., the main grids in related technologies are straight main grids. When solder ribbons are welded to the main grids, if the solder ribbons are not positioned accurately, causing a slight offset between the placement of the solder ribbons and the target position (the location of the main grids) in the first direction, the contact area between the solder ribbons and the main grids will be small, resulting in lower reliability of the connection between the solder ribbons and the main grids.

[0035] This disclosure provides a solar cell and a photovoltaic module. In the solar cell, a plurality of second grid lines are arranged at intervals along a first direction. The main body of the second grid lines includes alternating first and second segments. The projection of the first segment in the thickness direction of the substrate is wavy, which allows the solder ribbon to make electrical contact with the wavy first segment even if the solder ribbon slightly shifts in the first direction during welding to the second grid lines. This results in a larger contact area between the solder ribbon and the first segment compared to the contact area between the linear second grid lines and the solder ribbon in related technologies, thereby improving the connection reliability between the second grid lines and the solder ribbon. The linear projection of the first segment in the thickness direction of the substrate helps save material for the second grid lines, thus reducing the manufacturing cost of the solar cell.

[0036] Along the first direction, the width of the end portion is greater than the width of the main body. That is, the end portion of the second grid line has a larger width along the first direction, ensuring that the solder ribbon can still make electrical contact with the end portion even when there is a slight offset in the first direction. This also helps improve the connection reliability between the second grid line and the solder ribbon. Furthermore, the wider width at the end portion reduces the end resistance, preventing heat concentration due to excessive end resistance, which could negatively impact the performance of the solar cell, thus also contributing to improved solar cell performance.

[0037] The width of the first grid line located on the edge region is greater than the width of the first grid line located on the middle region. That is, the width of the first grid line located on the edge region is larger, which can reduce the risk of grid breakage of the first grid line on the edge region, and can also improve the efficiency of the first grid line in collecting charge carriers on the edge region, thereby also helping to improve the performance of the solar cell.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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).

[0042] 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.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] Figure 1 This is a schematic diagram of a solar cell provided in an embodiment of the present disclosure.

[0048] refer to Figure 1 The solar cell includes: a substrate 10, a plurality of first grid lines 11 and a plurality of second grid lines 12. The substrate 10 includes a central region 101 and edge regions 102 located on opposite sides of the central region 101 in a first direction X. A plurality of first gate lines 11 are spaced apart on the substrate 10 along a second direction Y. In the second direction Y, the width of the first gate lines 11 located on the edge regions 102 is greater than the width of the first gate lines 11 located on the central region 101. A plurality of second gate lines 12 are spaced apart on the substrate 10 along the first direction X and are electrically connected to the first gate lines 11. The second gate lines 12 include a main body 121 and end portions 122 located at opposite ends of the main body 121 in the second direction Y. In the first direction X, the width of the end portions 122 is greater than the width of the main body 121. The main body 121 includes a first segment 1211 and a second segment 1212 alternately distributed in the second direction Y. The projection of the first segment 1211 in the thickness direction of the substrate 10 is wavy, and the projection of the second segment 1212 in the thickness direction of the substrate 10 is straight.

[0049] The solar cell is one or any combination of PERC (Passivated Emitter Rear Cell), TOPCON (Tunnel Oxide Passivated Contact), heterojunction cell, thin-film solar cell, and tandem cell. Thin-film solar cells include, but are not limited to, perovskite thin-film solar cells, copper indium selenide (CIGS) thin-film solar cells, gallium arsenide (GaAs) thin-film solar cells, and cadmium sulfide (CdS) thin-film solar cells. Tandem cells include, but are not limited to, perovskite cells stacked with crystalline silicon cells, perovskite cells stacked with perovskite cells, and perovskite cells stacked with thin-film cells.

[0050] The substrate 10 is used to receive incident light and generate photogenerated carriers. In some embodiments, the substrate 10 may be a semiconductor substrate.

[0051] In some embodiments, the material of the substrate 10 may be an elemental semiconductor material. Specifically, the elemental semiconductor material is composed of a single element, such as silicon or germanium. The elemental semiconductor material may be monocrystalline, polycrystalline, amorphous, or microcrystalline (a state simultaneously possessing both monocrystalline and amorphous states is called microcrystalline). For example, silicon may be at least one of monocrystalline silicon, polycrystalline silicon, amorphous silicon, and microcrystalline silicon.

[0052] In some embodiments, the substrate 10 may also be a compound semiconductor material. Common compound semiconductor materials include, but are not limited to, silicon germanide, silicon carbide, gallium arsenide, indium gallium arsenide, perovskite, cadmium telluride, copper indium selenide, etc.

[0053] The substrate 10 can also be a sapphire substrate, a silicon substrate on an insulator, or a germanium substrate on an insulator.

[0054] The substrate 10 can be an N-type semiconductor substrate or a P-type semiconductor substrate. The N-type semiconductor substrate is doped with an N-type dopant element, which can be at least one of group V elements such as phosphorus (P), bismuth (Bi), antimony (Sb), or arsenic (As). The P-type semiconductor substrate 10 is doped with a P-type dopant element, which can be at least one of group III elements such as boron (B), aluminum (Al), gallium (Ga), or indium (In).

[0055] Figure 2 This is a partial cross-sectional view of a solar cell provided in an embodiment of this disclosure.

[0056] Reference Figure 1 and Figure 2The substrate 10 has a first surface 103 and a second surface 104 facing each other. In some embodiments, the solar cell is a single-sided cell, in which case the first surface 103 can serve as a light-receiving surface to receive incident light, and the second surface 104 serves as a backlight surface. In some embodiments, the solar cell is a double-sided cell, in which case both the first surface 103 and the second surface 104 can serve as light-receiving surfaces and can both be used to receive incident light. It is understood that the backlight surface referred to in the embodiments of this application 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 backlight surface.

[0057] In some embodiments, a texturing process can be performed on at least one of the first and second surfaces of the substrate to form a textured surface on at least one of the first and second surfaces of the substrate. This can enhance the absorption and utilization efficiency of incident light on the first and second surfaces of the substrate. 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 surface but also forms light traps, enhancing the absorption effect of the substrate on incident light and improving the photoelectric conversion efficiency of the solar cell.

[0058] The thickness direction of the substrate 10 is parallel to the direction from the second surface 104 to the first surface 103.

[0059] In some embodiments, the solar cell further includes a doped conductive layer (not shown) located on at least one of the first surface 103 and the second surface 104. The doped conductive layer is doped with an N-type dopant or a P-type dopant.

[0060] The material doped with the conductive layer may include at least one of amorphous silicon, polycrystalline silicon, or silicon carbide.

[0061] The solar cell also includes a passivation layer (not shown), at least part of which is located on the surface of the doped conductive layer away from the substrate 10.

[0062] The first gate line 11 is a fine gate, used for electrical contact with the doped conductive layer to collect current.

[0063] It should be noted that, Figure 2 Taking TOPCON batteries as an example, and Figure 2 Only the first grid line 11 on the first surface 103 is shown; the first grid line 11 on the second surface 104 is not shown.

[0064] In some embodiments, the first gate line 11 is in electrical contact with the doped conductive layer.

[0065] A method for forming the first gate line 11 may include printing a metal paste onto a portion of the passivation layer surface using a screen printing process. In some embodiments, the metal paste may include at least one of silver, aluminum, copper, tin, gold, lead, or nickel.

[0066] In some embodiments, the solar cell may further include a wrap-around coating (not shown) located on the edge region 102.

[0067] The coating on the first surface 103 is a byproduct formed on the edge region 102 of the first surface 103 when a doped conductive or passivation layer is formed on the second surface 104. The coating on the second surface 104 is a byproduct formed on the edge region 102 of the second surface 104 when a doped conductive or passivation layer is formed on the first surface 103.

[0068] The width of the first gate line 11 located on the edge region 102 is greater than the width of the first gate line 11 located on the middle region 101. That is, the width of the first gate line 11 on the edge region 102 is larger, which allows for more metal paste to be printed on the first gate line 11 on the edge region 102 during fabrication. This facilitates the metal paste penetrating the surrounding plating layer on the edge region 102, ensuring the contact effect between the first gate line 11 on the edge region 102 and the doped conductive layer.

[0069] In other embodiments, the solar cell may also not include a coating.

[0070] In some embodiments, the ratio of the length of the edge region 102 along the first direction X to the length of the base 10 along the first direction X is less than or equal to one-quarter, for example, one-eighth, one-sixth, one-fifth or one-quarter.

[0071] The remaining area on the substrate 10, excluding the two edge regions 102, is the middle region 101.

[0072] In some embodiments, the width of the first gate line 11 located on the edge region 102 along the second direction Y is 38μm to 48μm, for example, 38μm, 40μm, 43μm, 45μm or 48μm. The width of the first gate line 11 on the edge region 102 is within the above range, which makes the width of the first gate line 11 on the edge region 102 larger, which is beneficial to improving the current collection efficiency of the first gate line 11 on the edge region 102.

[0073] The width of the first gate line 11 located on the intermediate region 101 along the second direction Y is 28μm to 38μm, for example, 28μm, 30μm, 32μm, 35μm or 38μm. The width of the first gate line 11 on the intermediate region 101 is within the above range, which makes the width of the first gate line 11 on the intermediate region 101 smaller, which is beneficial to reducing the light-blocking area of ​​the first gate line 11 on the intermediate region 101 on the substrate 10.

[0074] In some embodiments, the distance between two adjacent first gate lines 11 along the second direction Y is 0.5mm to 2mm, for example 0.5mm, 0.8mm, 1mm, 1.5mm or 2mm.

[0075] Figure 3 This is a schematic diagram of a structure of the first grid line in a solar cell provided in an embodiment of this disclosure.

[0076] Reference Figure 1 and Figure 3 In some embodiments, the first grid line 11 includes a first portion 111 and a second portion 112 disposed along a first direction X. In a direction away from the second portion 112, the width of the first portion 111 gradually increases along the second direction Y; similarly, in a direction away from the first portion 111, the width of the second portion 112 gradually increases along the second direction Y. That is, the width of the first grid line 11 along the second direction Y is gradually varied, resulting in a uniform variation of the current collected by the first grid line 11 per unit area, which is beneficial for improving the performance of the solar cell.

[0077] In some embodiments, in the first direction X, the length of the first portion 111 may be equal to the length of the second portion 112.

[0078] Continue to refer to Figure 1 The second gate line 12 is the main gate, and it is connected to the first gate line 11 to collect the current collected by the first gate line 11. The second gate line 12 is also used to electrically connect to the solder strip to transmit the collected current to the solder strip.

[0079] The material of the second gate line 12 may include at least one of silver, aluminum, copper, tin, gold, lead, or nickel.

[0080] Figure 4 This is a schematic diagram of an end structure of a solar cell provided in an embodiment of the present disclosure.

[0081] refer to Figure 1 and Figure 4 The end portion 122 is located at both ends of the second grid line 12. The width of the end portion 122 is greater than the width of the main body 121. That is, the width of the end portion 122 of the second grid line 12 along the first direction X is larger, so that even if the solder ribbon is slightly offset in the first direction X, the solder ribbon can still make electrical contact with the end portion 122, which also helps to improve the connection reliability between the second grid line 12 and the solder ribbon. In addition, the wider width of the end portion 122 can reduce the resistance of the end portion 122, which can avoid heat concentration due to excessive resistance of the end portion 122, thereby avoiding affecting the performance of the solar cell, which also helps to improve the performance of the solar cell.

[0082] In some embodiments, the length of the end portion 122 along the second direction Y is 0.8 mm to 1.5 mm, for example 0.8 mm, 1 mm, 1.3 mm or 1.5 mm.

[0083] In some embodiments, the width of the end portion 122 gradually increases along the first direction X in the direction from the main body 121 to the end portion 122. That is, the width of the end portion 122 along the first direction X is gradual, which is beneficial for cost savings and allows the current collected in the end portion 122 per unit area to vary uniformly.

[0084] In some embodiments, the width W1 of the edge of the end portion 122 away from the main body portion 121 along the first direction X is 45μm to 55μm, for example 45μm, 48μm, 50μm, 53μm or 55μm.

[0085] The width of the main body 121 along the first direction X is 35μm to 45μm, for example 35μm, 38μm, 40μm, 43μm or 45μm.

[0086] Figure 5 This is a partial structural diagram of the first grid line and the first segment in a solar cell provided in an embodiment of the present disclosure.

[0087] Reference Figure 1 and Figure 5 The main body 121 includes alternating first segments 1211 and second segments 1212. The projection of the first segment 1211 along the thickness direction of the substrate 10 is wavy, allowing the solder ribbon to contact the wavy first segment 1211 even if there is a slight offset in the first direction X during welding of the solder ribbon to the second grid line 12. This results in a larger contact area between the solder ribbon and the first segment 1211 compared to the contact area between the straight second grid line and the solder ribbon, thereby improving the connection reliability between the second grid line 12 and the solder ribbon. The projection of the first segment 1211 along the thickness direction of the substrate 10 is linear, which helps save material on the second grid line 12, thus reducing the manufacturing cost of the solar cell.

[0088] When the solder strip is slightly offset in the first direction X, since the projection of the first segment 1211 in the thickness direction of the substrate 10 is wavy, the solder strip after offset in the first direction X can make electrical contact with the peak A, trough B or the rising or falling edge between the peak A and trough B of the wave, thereby increasing the contact area between the first segment 1211 and the solder strip.

[0089] The projection of the first segment 1211 onto the thickness direction of the base 10 is wavy, that is, the orthographic projection of the first segment 1211 onto the first surface 103 or the second surface 104 is wavy. The projection of the second segment 1212 onto the thickness direction of the base 10 is straight, that is, the orthographic projection of the second segment 1212 onto the first surface 103 or the second surface 104 is straight.

[0090] In some embodiments, the wave centerline of the first segment 1211 and the centerline of the second segment 1212 are located on the same straight line. The wave centerline of the first segment 1211 is the straight line containing the weighted average of the highest value of wave peak A and the lowest value of wave trough B.

[0091] In some embodiments, the wave shape of the first segment 1211 can be a sine wave. Thus, each wave crest A in the first segment 1211 is equidistant from the wave centerline along the first direction X, and each wave trough B is also equidistant from the wave centerline along the first direction X. This improves the battery's aesthetics and ensures that the solder strip can make electrical contact with the first segment 1211 regardless of slight offset on either side along the first direction X.

[0092] refer to Figure 1 In some embodiments, the first segment 1211 is electrically connected to at least two first gate lines 11, and the second segment 1212 is electrically connected to at least two first gate lines 11. That is, both the first segment 1211 and the second segment 1212 are in electrical contact with the first gate lines 11, and the number of electrically connected first gate lines 11 is greater than or equal to two, which is beneficial to improving the efficiency of the second gate line 12 in collecting the current on the first gate lines 11.

[0093] refer to Figure 5 In some embodiments, the first gate line 11 connected to the first segment 1211 is located between the crest A and trough B of the wave. That is, the first gate line 11 connected to the first segment 1211 is electrically connected to at least one of the rising and falling edges of the wave. Compared to the first gate line being connected to a crest or trough, the first gate line 11 being located between the crest A and trough B of the wave is beneficial to increasing the contact area between the first gate line 11 and the first segment 1211, thereby improving the efficiency of the first segment 1211 in collecting current from the first gate line 11.

[0094] In other embodiments, the first grid line 11 connected to the first segment 1211 may also be in electrical contact with the wavy crest A or trough B.

[0095] Continue to refer to Figure 1 In some embodiments, the thickness of the first segment 1211 may be equal to the thickness of the second segment 1212.

[0096] In some embodiments, along the second direction Y, the length of the first segment 1211 is equal to the length of the second segment 1212, and the width of the first segment 1211 is equal to the width of the second segment 1212, and the number of first gate lines 11 connected to the first segment 1211 is greater than the number of first gate lines 11 connected to the second segment 1212.

[0097] The width of the first segment 1211 is the width of the wavy first segment 1211 in the direction perpendicular to its extension, and the width of the second segment 1212 is the width of the second segment 1212 in the first direction X.

[0098] When the length of the first segment 1211 is equal to the length of the second segment 1212, and the width of the first segment 1211 is equal to the width of the second segment 1212, the projected area of ​​a single first segment 1211 in the thickness direction of the substrate 10 is greater than the projected area of ​​a single first segment 1211 in the thickness direction of the substrate 10. Making the number of first gate lines 11 connected to the first segment 1211 greater than the number of first gate lines 11 connected to the second segment 1212 can improve the efficiency of the second gate line 12 in collecting the current on the first gate line 11.

[0099] In some embodiments, along the second direction Y, the ratio of the length of the second segment 1212 to the length of the first segment 1211 is 2 / 3 to 6, for example 2 / 3, 1, 2, 3, 4, 5 or 6.

[0100] In some embodiments, the length of the first segment 1211 along the second direction Y is 0.5mm to 1.5mm, for example 0.5mm, 0.8mm, 1mm, 1.3mm or 1.5mm.

[0101] The length of the second segment 1212 is 1mm to 3mm, for example, 1mm, 1.5mm, 2mm, 2.5mm or 3mm.

[0102] In some embodiments, the amplitude of the wavy shape is 30 μm to 60 μm, for example, 30 μm, 40 μm, 50 μm, or 60 μm. The amplitude of the wavy shape refers to half the distance between adjacent peaks A and troughs B in the first direction X within the same first segment 1211. With the amplitude of the wavy shape within the above range, even if the solder strip slightly shifts in the first direction X during welding to the second gate line 12, the solder strip can still contact the wavy first segment 1211, thereby improving the connection reliability between the second gate line 12 and the solder strip.

[0103] The wavelength of the wavy shape is 150μm to 300μm, for example, 150μm, 200μm, 250μm, or 300μm. The wavelength of the wavy shape refers to the distance in the second direction Y between two adjacent peaks A, or the distance in the second direction Y between two adjacent troughs B, within the same first segment 1211. The wavelength of the wavy shape is negatively correlated with the projected area of ​​the wavy shape in the thickness direction of the substrate 10. A wavelength within the aforementioned range ensures a larger projected area of ​​the first segment 1211 in the thickness direction of the substrate 10, which is beneficial for improving the current collection capability of the first segment 1211 and avoids wasting resources due to an excessively large projected area of ​​the first segment 1211 in the thickness direction of the substrate 10.

[0104] Figure 6 This is a schematic diagram of another structure of a solar cell provided in an embodiment of this disclosure.

[0105] refer to Figure 1 and 6 In some embodiments, the solar cell further includes a welding portion 13, which is electrically connected to the second grid line 12. Multiple welding portions electrically connected to the same second grid line 12 are located on the same straight line. The welding portion 13 is used to electrically connect the second grid line 12 and the solder strip. When the solder strip is electrically connected to the second grid line 12, the extension direction of the solder strip is parallel to the second direction Y. The fact that multiple welding portions 13 electrically connected to the same second grid line 12 are located on the same straight line, and that the extension direction of this straight line can be parallel to the second direction Y, facilitates the welding of the solder strip to the welding portion 13 and makes the electrical connection between the solder strip and the second grid line 12 easier.

[0106] The phrase "multiple welded parts 13 located on the same straight line" means that the geometric centers of multiple welded parts 13 are located on the same straight line.

[0107] The material of the weld 13 is at least one of silver, aluminum, copper, tin, gold, lead or nickel.

[0108] In some embodiments, the length of the weld portion 13 along the first direction X is greater than the length of the weld portion 13 along the second direction Y. This allows for a larger length of the weld portion 13 in the first direction X, ensuring that the solder strip can still make electrical contact with the weld portion 13 even if there is a slight misalignment in the first direction X. Simultaneously, the length of the weld portion 13 in the second direction Y can be smaller, which helps to reduce the manufacturing cost of the weld portion 13.

[0109] When the welded part 13 is electrically connected to the first wavy section 1211, it can be electrically connected to the crest, trough, or rising or falling edge between the crest and trough of the wave.

[0110] Understandable, Figure 6The illustration shows the case where the projection shape of the welded part 13 in the thickness direction of the substrate 10 is rectangular. In reality, the projection shape of the welded part in the thickness direction of the solar cell can also be other shapes such as circles, squares, pentagons, and ellipses.

[0111] This disclosure also provides a photovoltaic module in some embodiments, which may include the solar cells in any of the above embodiments. It should be noted that parts that are the same as or corresponding to the above embodiments can be referred to the above embodiments, and will not be repeated hereafter.

[0112] Figure 7 This is a schematic diagram of a photovoltaic module provided in an embodiment of the present disclosure.

[0113] refer to Figure 7 The photovoltaic module includes a battery string, which is formed by connecting multiple solar cells 20 as described in any of the above embodiments. The photovoltaic module also includes an encapsulating film 21 and a cover plate 22, wherein the encapsulating film 21 is used to cover the surface of the battery string, and the cover plate 22 is used to cover the surface of the encapsulating film 21 away from the battery string.

[0114] In some embodiments, the battery string further includes a solder strip 23 for electrically connecting adjacent solar cells 20.

[0115] In some embodiments, the encapsulating film 21 includes a first encapsulating layer and a second encapsulating layer. The first encapsulating layer covers one of the front and back sides of the solar cell, and the second encapsulating layer covers the other of the front and 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.

[0116] 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 21.

[0117] In some embodiments, the cover plate 22 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 22 facing the encapsulating film 21 can be an uneven surface or a textured surface containing multiple raised structures, thereby increasing the utilization rate of incident light. The cover plate 22 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.

[0118] 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 this disclosure. Any person skilled in the art can make various alterations and modifications without departing from the spirit and scope of this disclosure; therefore, the scope of protection of this disclosure should be determined by the scope defined in the claims.

Claims

1. A solar cell, characterized in that, include: A substrate, the substrate including a central region and edge regions located on opposite sides of the central region in a first direction; A plurality of first gate lines are distributed at intervals along a second direction on the substrate, wherein, along the second direction, the width of the first gate line located on the edge region is greater than the width of the first gate line located on the middle region; A plurality of second gate lines are spaced apart on the substrate along the first direction and electrically connected to the first gate line. Each second gate line includes a main body and ends located at opposite ends of the main body in the second direction. Along the first direction, the width of the ends is greater than the width of the main body. The main body includes a first segment and a second segment alternately distributed along the second direction. The projection of the first segment in the thickness direction of the substrate is wavy, and the projection of the second segment in the thickness direction of the substrate is straight. The second gate line is the main gate.

2. The solar cell according to claim 1, characterized in that, The first segment is electrically connected to at least two of the first gate lines, and the second segment is electrically connected to at least two of the first gate lines.

3. The solar cell according to claim 1, characterized in that, The first grid line connected to the first segment is located between the crests and troughs of the wave.

4. The solar cell according to claim 1, characterized in that, Along the second direction, the length of the first segment is equal to the length of the second segment, and the width of the first segment is equal to the width of the second segment, and the number of first gate lines connected to the first segment is greater than the number of first gate lines connected to the second segment.

5. The solar cell according to claim 1, characterized in that, Along the second direction, the ratio of the length of the second segment to the length of the first segment is 2 / 3 to 6.

6. The solar cell according to claim 5, characterized in that, Along the second direction, the length of the first segment is 0.5mm to 1.5mm, and the length of the second segment is 1mm to 3mm.

7. The solar cell according to claim 1, characterized in that, The amplitude of the wave shape is 30μm~60μm, and the wavelength of the wave shape is 150μm~300μm.

8. The solar cell according to claim 1, characterized in that, The width of the first gate line located on the edge region along the second direction is 38μm~48μm, and the width of the first gate line located on the middle region along the second direction is 28μm~38μm.

9. The solar cell according to claim 1, characterized in that, The first grid line includes a first portion and a second portion disposed along the first direction. In the direction away from the second portion, the width of the first portion gradually increases along the second direction; in the direction away from the first portion, the width of the second portion gradually increases along the second direction.

10. The solar cell according to claim 1, characterized in that, The length of the end along the second direction is 0.8mm to 1.5mm.

11. The solar cell according to claim 1, characterized in that, In the direction from the main body to the end portion, the width of the end portion gradually increases along the first direction.

12. The solar cell according to claim 11, characterized in that, The width of the edge of the end portion away from the main body portion along the first direction is 45μm~55μm, and the width of the main body portion along the first direction is 35μm~45μm.

13. The solar cell according to claim 1, characterized in that, The solar cell also includes: A welding section, wherein the welding section is electrically connected to the second grid line, and a plurality of welding sections electrically connected to the same second grid line are located on the same straight line.

14. The solar cell according to claim 13, characterized in that, The length of the welded portion along the first direction is greater than the length of the welded portion along the second direction.

15. A photovoltaic module, characterized in that, include: A battery string, comprising a plurality of solar cells connected together as described in any one of claims 1 to 14; 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 facing away from the battery string.

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