Solar cells and photovoltaic modules

Abstract

The application relates to a solar cell and a photovoltaic module. The solar cell comprises a cell body; a seed layer is arranged on the cell body; a grid line is arranged on the side of the seed layer away from the cell body, the surface of the side of the grid line facing the cell body comprises a first sub-surface and a second sub-surface, the first sub-surface is in contact with the seed layer, and the second sub-surface is in contact with the cell body; wherein the ratio of the area of the orthographic projection of the first sub-surface on the cell body to the area of the orthographic projection of the second sub-surface on the cell body is greater than or equal to two-sevenths. Therefore, the solar cell and the photovoltaic module provided by the application are beneficial to reducing the probability of grid line falling off.

Description

Technical Field

[0001] This application relates to the field of photovoltaic technology, and in particular to solar cells and photovoltaic modules. Background Technology

[0002] Solar cells, also known as photovoltaic cells, are semiconductor devices that directly convert sunlight into electrical energy. Because they are green and environmentally friendly products that do not cause pollution, and because solar energy is a renewable resource, solar cells are a new type of battery with broad development prospects.

[0003] In related technologies, solar cells include a cell body and a copper grid. The copper grid is fabricated using methods such as laser transfer printing, stencil printing, and meshless processes. However, the aforementioned copper grid is prone to detaching from the cell body. Utility Model Content

[0004] Therefore, it is necessary to provide a solar cell and photovoltaic module that can help reduce the probability of grid line detachment.

[0005] In a first aspect, embodiments of this application provide a solar cell, comprising:

[0006] Battery body;

[0007] The seed layer is located on the battery body;

[0008] The grid line is located on the side of the seed layer away from the battery body. The surface of the grid line facing the battery body includes a first sub-surface and a second sub-surface. The first sub-surface is in contact with the seed layer, and the second sub-surface is in contact with the battery body.

[0009] The ratio of the area of ​​the first sub-surface projected onto the battery body to the area of ​​the second sub-surface projected onto the battery body is greater than or equal to two-sevenths.

[0010] In one embodiment, a first cross-section is defined on the grid line, the first cross-section being perpendicular to the extension direction of the grid line; in the thickness direction of the battery body, the point on the first cross-section that is farthest from the second sub-surface is the first point; among the lines in contact between the first cross-section and the battery body, the point that is farthest from the center of the first cross-section in a first direction is the second point, the first direction being perpendicular to the extension direction of the grid line.

[0011] The line connecting the first point and the second point is the first connecting line. The angle between the first connecting line and the second sub-face is greater than or equal to 20 degrees and less than 90 degrees.

[0012] In one embodiment, the ratio of the size of the gate line along the first direction to the size of the seed layer along the first direction is less than or equal to 3:1, and the first direction is perpendicular to the extension direction of the gate line.

[0013] In one embodiment, the seed layer includes a plurality of extension segments spaced apart along the extension direction of the gate lines, with gaps between adjacent extension segments, and a portion of the gate lines located in the gaps.

[0014] In one embodiment, the plurality of extension segments are arranged in a straight line along the extension direction of the gate line; or...

[0015] The two adjacent extension segments are staggered along the extension direction of the grid line.

[0016] In one embodiment, the distance between two adjacent extension segments is less than or equal to 100 μm; and / or,

[0017] The dimension of the extension segment along the extension direction of the grid line is greater than or equal to 30 μm; and / or,

[0018] The sum of the dimensions of multiple extension segments along the extension direction of the grid line is greater than or equal to the sum of the dimensions of all gaps along the extension direction of the grid line.

[0019] In one embodiment, a first recess is provided on one side of the seed layer along a first direction, and a portion of the gate line is located within the first recess. The first direction is perpendicular to the extension direction of the gate line.

[0020] In one embodiment, a second recess is provided on the other side of the seed layer along the first direction, and a portion of the gate lines are located within the second recess.

[0021] In one embodiment, the seed layer includes a first sub-section and a second sub-section arranged alternately along the extension direction of the gate line, with a first recessed portion corresponding to the second sub-section and the first recessed portion located on one side of the corresponding second sub-section.

[0022] In one embodiment, the second recess is provided corresponding to the second sub-part, and the second recess is located on the other side of the corresponding second sub-part.

[0023] The dimension of the first sub-part along the first direction is greater than the dimension of the second sub-part along the first direction.

[0024] In one embodiment, the second sub-face includes a first side away from the seed layer, the first side and the seed layer are spaced apart along a first direction, and the distance between the first side and the first sub-face is less than the distance between the first side and the second sub-face.

[0025] In one embodiment, the second recess is disposed corresponding to the first sub-part, and the second recess is located on the side of the corresponding first sub-part that is away from the first recess.

[0026] The dimension of the first sub-part along the first direction is equal to the dimension of the second sub-part along the first direction.

[0027] In one embodiment, the second sub-face includes a first side away from the seed layer, the first side and the seed layer being spaced apart along a first direction;

[0028] On the side of the seed layer facing the first depression, the distance between the first side and the first sub-part is less than the distance between the first side and the second sub-part.

[0029] On the side of the seed layer facing the second depression, the distance between the first side and the first sub-part is greater than the distance between the first side and the second sub-part.

[0030] In one embodiment, the dimensions of the gate line along a first direction are equal everywhere along the extension direction of the gate line, and the first direction is perpendicular to the extension direction of the gate line.

[0031] In one embodiment, the surface of the seed layer facing the gate line includes a plurality of sub-convex surfaces, which are arranged along the thickness direction of the battery body. The sub-convex surfaces protrude in a direction away from the center of the seed layer, and a third recess is provided between two adjacent sub-convex surfaces, with a portion of the gate line located in the third recess.

[0032] In one embodiment, the seed layer has pores, and some of the grid lines are located in the pores.

[0033] In one embodiment, the seed layer includes a first sub-layer and a second sub-layer stacked in a direction away from the battery body, both of which are in contact with the grid lines.

[0034] Both the first and second sublayers have pores, with the pore diameter in the first sublayer being larger than that in the second sublayer.

[0035] In one embodiment, the seed layer includes a third sub-layer, which is located on the side of the first sub-layer opposite to the second sub-layer. The third sub-layer is inserted into the battery body, and the first and second sub-layers protrude from the battery body.

[0036] The pore size in the third sublayer is smaller than the pore size in the first sublayer.

[0037] In one embodiment, the seed layer includes a fourth sub-layer and a fifth sub-layer, both of which have pores. The fifth sub-layer is located between the gate line and the fourth sub-layer, and the fifth sub-layer is in contact with the gate line. The fourth sub-layer is spaced apart from the gate line.

[0038] The pore size in the fifth sublayer is larger than that in the fourth sublayer.

[0039] In one embodiment, the distance between the face of the gate line near the seed layer and the face of the gate line away from the seed layer is a third distance, and the third distance of the gate line gradually decreases from the center of the gate line to the edge along the first direction; the first direction is perpendicular to the extension direction of the gate line.

[0040] In one embodiment, the size of the gate line along the first direction ranges from 20 μm to 70 μm; and / or,

[0041] The seed layer has a size ranging from 5 μm to 30 μm along the first direction; and / or,

[0042] The ratio of the maximum distance between the face of the grid line away from the seed layer and the second sub-face along the thickness direction of the battery body to the dimension of the grid line along the first direction is greater than or equal to 0.3; and / or,

[0043] The contact resistance between the grid line and the seed layer is less than or equal to 0.1 Ω·cm²;

[0044] The first direction is perpendicular to the extension direction of the grid line.

[0045] Secondly, embodiments of this application provide a photovoltaic module, including the solar cell of the first aspect.

[0046] The solar cell provided in this application embodiment has a larger area ratio for the second sub-surface because the ratio of the area of ​​the first sub-surface projected onto the cell body to the area of ​​the second sub-surface projected onto the cell body is greater than or equal to two-sevenths. This allows the stress-bearing area of ​​the grid lines to be mainly concentrated above the seed layer, resulting in a stronger bond between the seed layer and the grid lines. This concentrated stress ensures that the bond between the seed layer and the grid lines is strong enough to hold the grid lines in place, preventing them from falling off and reducing the risk of water damage. This improves the stability and reliability of the cell, reduces resistance, and increases conversion efficiency. Attached Figure Description

[0047] Figure 1 This is a schematic diagram of the structure of a solar cell provided in an embodiment of this application.

[0048] Figure 2 for Figure 1 A sectional view along the EE direction.

[0049] Figure 3 A partial cross-sectional view of a solar cell provided in an embodiment of this application.

[0050] Figure 4 Another partial cross-sectional view of a solar cell provided in an embodiment of this application.

[0051] Figure 5 Another partial cross-sectional view of a solar cell provided in an embodiment of this application.

[0052] Figure 6 This is a top view of the seed layer and gate lines provided in an embodiment of this application.

[0053] Figure 7Another top view of the seed layer and gate lines provided in an embodiment of this application.

[0054] Figure 8 Another top view of the seed layer and gate lines provided in an embodiment of this application.

[0055] Figure 9 Another top view of the seed layer and gate lines provided in an embodiment of this application.

[0056] Figure 10 A cross-sectional view of the seed layer provided in an embodiment of this application.

[0057] Figure 11 Another cross-sectional view of the seed layer provided in an embodiment of this application.

[0058] Figure 12 A cross-sectional view of the seed layer and passivation layer provided in an embodiment of this application.

[0059] Figure 13 Another cross-sectional view of the seed layer and passivation layer provided in an embodiment of this application.

[0060] Figure 14 A cross-sectional view of the seed layer, passivation layer, and gate lines provided in an embodiment of this application.

[0061] Figure 15 Another top view of the seed layer and gate lines provided in an embodiment of this application.

[0062] Explanation of reference numerals in the attached figures:

[0063] 100. Solar cell; 101. Cell body; 110. Semiconductor substrate; 120. Doped semiconductor layer; 130. Passivation layer; 140. Seed layer; 140a. Extension segment; 141. First sub-section; 142. Second sub-section; 143. Third surface; 1431. Sub-convex surface; 144. Gap; 1451. First recess; 1452. Second recess; 1453. Third recess; 146. Pore; 151. First sub-layer; 152. Second sub-layer; 153. Third sub-layer; 154. Fourth sub-layer; 155. Fifth sub-layer; 160. Grid line; 161. First surface; 1611. First sub-surface; 1612. Second sub-surface; 162. Second surface; A. First point; B. Second point; L1. First edge; X. First direction; Y. Second direction; Z. Third direction. Detailed Implementation

[0064] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0065] Furthermore, where the terms "first" and "second" appear, these terms are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, where the term "multiple" appears, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0066] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., 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, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0067] In this application, unless otherwise expressly specified and limited, the use of descriptions such as "above" or "below" the second feature indicates that the first and second features are in direct contact or indirect contact via an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. Similarly, "below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0068] It should be noted that if an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. If an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. If so, the terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used in this application are for illustrative purposes only and do not represent the only possible implementation.

[0069] In related technologies, since silver is an important precious metal resource, its crustal reserves are insufficient to support the rapid development of the photovoltaic industry. The high price of raw materials will have an adverse impact on the cost of future photovoltaic manufacturing. Therefore, copper grid technology has been widely used in photovoltaic cells, integrated circuits and other fields.

[0070] However, due to insufficient control of the angle between the side and bottom surfaces of the copper gate, and an imbalance in the width ratio between the copper gate and the seed layer, problems arise. In traditional processes, the angle between the side and bottom surfaces of the copper gate is often less than 20°. This results in an excessively large contact area between the copper gate and the SiNx layer, leading to interface stress concentration and reduced adhesion. This makes the copper gate prone to detachment and also negatively impacts the gate height and resistivity. Furthermore, a mismatch in the width ratio between the copper gate and the seed layer (such as a silver seed layer) leads to insufficient bonding, thus affecting the long-term reliability of the device.

[0071] To address the aforementioned issues, embodiments of this application provide a solar cell and a photovoltaic module that can improve the bonding force between the overall structure formed by the cell body and the seed layer and the grid lines, thereby helping to prevent the grid lines from falling off.

[0072] The following will combine Figures 1-15 The solar cell 100 and photovoltaic module provided in the embodiments of this application will be described.

[0073] This application provides a solar cell 100, which includes a cell body 101, a seed layer 140, and grid lines 160. The seed layer 140 and the grid lines 160 are both disposed on the cell body 101. The grid lines 160 are disposed on the side of the seed layer 140 opposite to the cell body 101.

[0074] For example, the gate line 160 extends along the second direction Y, and the first direction X intersects the second direction Y, for example, they are perpendicular to each other.

[0075] It should be noted that the solar cell 100 can have at least one seed layer 140 and at least one grid line 160. When there are multiple seed layers 140 and multiple grid lines 160, the multiple grid lines 160 can be arranged at intervals, for example, the multiple grid lines 160 can be arranged at intervals along the first direction X. The seed layer 140 and the grid line 160 can be correspondingly arranged, with the grid line 160 located on the side of the corresponding seed layer 140 facing away from the cell body 101. For example, the grid line 160 and the seed layer 140 can be arranged in a one-to-one correspondence. The following embodiments illustrate the grid line 160 and the corresponding seed layer 140.

[0076] See Figure 2The surface of the grid line 160 facing the battery body 101 is the first surface 161. The first surface 161 includes a first sub-surface 1611 and a second sub-surface 1612. The first sub-surface 1611 is in contact with the seed layer 140, and the second sub-surface 1612 is in contact with the battery body 101. The bonding force between the second sub-surface 1612 and the battery body 101 is weak, while the bonding force between the first sub-surface 1611 and the seed layer 140 is strong. When the second sub-surface 1612 occupies a large proportion of the first surface 161, the stress on the grid line 160 mainly depends on the weak bonding force between it and the battery body 101. Once subjected to external force, stress concentration is easily generated at the interface, causing the grid line 160 to detach. The ratio of the area of ​​the first sub-surface 1611 projected onto the battery body 101 to the area of ​​the second sub-surface 1612 projected onto the battery body 101 is greater than or equal to two-sevenths, resulting in a larger area of ​​the second sub-surface 1612. The stress area of ​​the grid line 160 is mainly concentrated above the seed layer 140, and the bonding force between the seed layer 140 and the grid line 160 is stronger, which can make the stress more concentrated. The bonding force between the seed layer 140 and the grid line 160 is sufficient to hold the grid line 160, ensuring that the grid line 160 will not fall off, reducing the risk of boiling in water, improving the stability and reliability of the battery, and reducing resistance and improving conversion efficiency.

[0077] Specifically, the adhesion between the grid line 160 and the seed layer 140 is greater than the adhesion between the grid line 160 and the battery body 101, resulting in a stronger bond between the grid line 160 and the seed layer 140 than between the grid line 160 and the battery body 101. The seed layer 140 can be used to improve the bond between the overall structure formed by the battery body 101 and the seed layer 140 and the grid line 160, which helps to reduce the peeling of the grid line 160 and improve the structural stability of the grid line 160.

[0078] For example, the ratio of the area of ​​the first sub-surface 1611 projected onto the battery body 101 to the area of ​​the second sub-surface 1612 projected onto the battery body 101 can be any value greater than 2 / 7, 3 / 7, 1 / 2, 4 / 7, 5 / 7, 6 / 7, or 2 / 7.

[0079] For example, both the grid line 160 and the seed layer 140 can be made of metal materials, and the material of the contact portion between the battery body 101 and the grid line 160 can be an insulating material. The bonding force between the metal material of the grid line 160 and the metal material of the seed layer 140 can be greater than the bonding force between the metal material of the grid line 160 and the insulating material of the passivation layer 130.

[0080] For example, the outer surface of the gate line 160 may be a convex shape.

[0081] In some embodiments, see Figure 2The gate line 160 is defined to have a first cross-section, the first cross-section being perpendicular to the extension direction of the gate line 160. Figure 2 The cross-section of the grid line 160 shown can be a first cross-section. In the thickness direction of the battery body 101, the point on the first cross-section farthest from the second sub-surface 1612 is the first point A. The side of the grid line 160 facing away from the seed layer 140 is the first line on the first cross-section. The highest point on the first line relative to the plane containing the first sub-surface 1611 is the first point A. Among the lines in contact between the first cross-section and the battery body 101, the point farthest from the center of the first cross-section in the first direction X is the second point B. The line connecting the first point A and the second point B is the first connecting line AB. The angle between the first connecting line AB and the second sub-surface 1612 is greater than or equal to 20 degrees and less than 90 degrees. Thus, a seed layer 140 is first formed on the battery body 101, and then the grid line 160 is wrapped around the outer surface of the seed layer 140. The bonding force between the grid line 160 and the seed layer 140 is strong, while the bonding force between the grid line 160 and the battery body 101 is weak. When the angle θ is less than 20 degrees, the stress zone of the grid line 160 extends significantly beyond the seed layer 140. The stress on the grid line 160 mainly relies on the weak bonding force between it and the battery body 101. Once subjected to external force, stress concentration easily occurs at the interface, leading to the grid line 160 detaching. When the angle θ is greater than or equal to 20 degrees and less than 90 degrees, as the angle θ increases, the stress zone of the grid line 160 is mainly concentrated above the seed layer 140. The stress on the grid line 160 is mainly transmitted to the seed layer 140 through the interface between the grid line 160 and the seed layer 140. The stronger bonding force between the seed layer 140 and the grid line 160 allows for more concentrated stress. The bonding force between the seed layer 140 and the grid line 160 is sufficient to hold the grid line 160 in place, ensuring it does not detach, reducing the risk of water damage, and improving the stability and reliability of the battery. Furthermore, it can reduce resistance and improve conversion efficiency.

[0082] The first line AB is a virtual line and does not actually exist.

[0083] In some embodiments, see Figure 2 The angle θ between the first connecting line AB and the second sub-face 1612 is in the range of 30 degrees to 60 degrees. This angle θ can make the force distribution of the gate line 160 above the seed layer 140 more reasonable, and further improve the bonding force between the seed layer 140 and the gate line 160.

[0084] For example, the angle θ between the first line AB and the second sub-plane 1612 can be 20 degrees, 30 degrees, 40 degrees, 45 degrees, 50 degrees, 60 degrees, 70 degrees, 80 degrees, 90 degrees, or any value between 20 degrees and 90 degrees.

[0085] In some embodiments, the ratio of the dimension W2 of the gate line 160 along the first direction X to the dimension W2 of the seed layer 140 along the first direction X is less than or equal to 3, that is, the width ratio of the gate line 160 to the seed layer 140 is less than or equal to 3. If the width ratio of the gate line 160 to the seed layer 140 is too large, a large number of gate lines 160 will come into contact with the battery body 101, resulting in a reduction in the contact area ratio of the gate line 160 to the seed layer 140. When the width ratio of the gate line 160 to the seed layer 140 is less than or equal to 3, the contact area ratio of the gate line 160 to the seed layer 140 can be made reasonable, ensuring adhesion and stability. Moreover, when the width ratio of the gate line 160 to the seed layer 140 is greater than or equal to 1.5, it can be ensured that the gate line 160 completely covers the seed layer 140.

[0086] For example, the width ratio of the gate line 160 to the seed layer 140 is 2-2.8.

[0087] Specifically, the width ratio of the gate line 160 to the seed layer 140 can be any value of 1.5, 2.0, 2.5, 2.8, 3.0 or less than 3.

[0088] In some embodiments, see Figure 15 The seed layer 140 can be continuously arranged along the second direction Y. One end of the seed layer 140 is located near the end of the gate line 160, and the other end of the seed layer 140 is located near the other end of the gate line 160. The one end of the seed layer 140 and the other end are connected as a single structure. In other words, both the gate line 160 and the seed layer 140 extend along the second direction Y.

[0089] In other embodiments, see Figure 6 The seed layer 140 can be discontinuously arranged along the second direction Y. The seed layer 140 includes a plurality of extension segments 140a spaced apart along the extension direction of the gate line 160. There is a gap 144 between two adjacent extension segments 140a. Part of the gate line 160 is located in the gap 144. In this way, by breaking the seed layer 140 into a plurality of extension segments 140a spaced apart along the extension direction of the gate line 160, the seed layer 140 is discontinuously arranged along the extension direction of the gate line 160, which is beneficial to reduce the material consumption of the seed layer 140 and reduce the manufacturing cost of the seed layer 140. In addition, since there is a gap 144 between two adjacent extension segments 140a and part of the gate line 160 is located in the gap 144, it is beneficial to increase the contact area between the seed layer 140 and the gate line 160, thereby improving the bonding force between the seed layer 140 and the gate line 160, so as to improve the bonding force between the overall structure formed by the seed layer 140 and the battery body 101 and the gate line 160.

[0090] In some embodiments, see Figure 15At least one of the end faces of the seed layer 140 along the second direction Y can be exposed outside the gate line 160. For example, the end face of one end of the seed layer 140 along the second direction Y is flush with the end face of one end of the gate line 160 along the second direction Y, and the end face of the other end of the seed layer 140 along the second direction Y is flush with the end face of the other end of the gate line 160 along the second direction Y.

[0091] In other embodiments, see Figure 6 and Figure 8 At least one of the end faces of the seed layer 140 along the second direction Y can be covered by the gate line 160.

[0092] In some embodiments, see Figure 6 Multiple extension segments 140a are arranged in a straight line along the extension direction of the gate line 160. This makes the arrangement of multiple extension segments 140a more regular, which helps to reduce the difficulty and cost of preparing the seed layer 140.

[0093] In other embodiments, see Figure 7 Two adjacent extension segments 140a are staggered along the extension direction of the gate line 160. The orthographic projections of two adjacent extension segments 140a along the second direction Y do not overlap. The centers of two adjacent extension segments 140a are spaced apart along the first direction X. This makes the multiple extension segments 140a more evenly distributed in the first direction X. Even if the gate line 160 is significantly misaligned along the first direction X during printing, there can still be a large contact area between the gate line 160 and a portion of the extension segments 140a, which is beneficial for improving the process window of the gate line 160.

[0094] For example, see Figure 6 The distance W3 between two adjacent extension segments 140a is less than or equal to 100 μm. This avoids excessively large distances between adjacent extension segments 140a, increases the arrangement density of extension segments 140a, improves the contact area between the seed layer 140 and the gate line 160, and also facilitates carrier transport between the seed layer 140 and the gate line 160. For example, the distance between two adjacent extension segments 140a can be any value of 10 μm, 20 μm, 50 μm, 70 μm, 100 μm, or less than 100 μm.

[0095] For example, see Figure 6 The dimension W4 of the extension segment 140a along the extension direction of the gate line 160 is greater than or equal to 30 μm. This avoids the extension segment 140a being too small along the extension direction of the gate line 160, which helps to increase the contact area between the individual extension segment 140a and the gate line 160, helps to avoid weak bonding between the gate line 160 and the individual extension segment 140a, and helps to reduce the risk of peeling between the gate line 160 and the individual extension segment 140a.

[0096] For example, the dimension of the extension 140a along the extension direction of the gate line 160 can be 30μm, 50μm, 100μm, 150μm, 200μm or any value greater than 30μm.

[0097] For example, see Figure 6 The sum of the dimensions of all extension segments 140a along the extension direction of the gate line 160 is greater than or equal to the sum of the dimensions of all gaps 144 along the extension direction of the gate line 160. This helps to avoid the sum of the dimensions of all extension segments 140a along the extension direction of the gate line 160 being too small, which helps to increase the contact area between the seed layer 140 and the gate line 160, and thus helps to improve the bonding force between the seed layer 140 and the gate line 160.

[0098] In some embodiments, see Figure 8 The seed layer 140 has a first recess 1451 on one side along the first direction X, and a portion of the gate line 160 is located in the first recess 1451. Thus, by providing the first recess 1451 on the seed layer 140 and embedding a portion of the gate line 160 in the first recess 1451, a fitting structure is formed between the gate line 160 and the seed layer 140, which helps to improve the bonding force between the seed layer 140 and the gate line 160.

[0099] In some embodiments, see Figure 8 The seed layer 140 has a second recess 1452 on the other side along the first direction X. A portion of the gate line 160 is located in the second recess 1452. By providing the second recess 1452 on the seed layer 140 and embedding a portion of the gate line 160 in the second recess 1452, a fitting structure is formed between the gate line 160 and the seed layer 140, which is beneficial to improving the bonding force between the seed layer 140 and the gate line 160.

[0100] In some embodiments, see Figure 8 The seed layer 140 includes alternating first sub-sections 141 and second sub-sections 142 arranged along the extension direction of the gate line 160, with at least partially adjacent first sub-sections 141 and second sub-sections 142 connected. In an embodiment where the seed layer 140 is continuously arranged along the second direction Y, each adjacent first sub-section 141 and second sub-section 142 of the seed layer 140 can be connected. For example, in an embodiment where the seed layer 140 includes multiple extension segments 140a, each extension segment 140a may include alternating first sub-sections 141 and second sub-sections 142 arranged along the extension direction of the gate line 160, with each adjacent first sub-section 141 and second sub-section 142 of the same extension segment 140a connected, and the first sub-section 141 of one adjacent extension segment 140a and the second sub-section 142 of the other adjacent extension segment 140a being spaced apart.

[0101] In some embodiments, see Figure 8 The first recessed portion 1451 is provided correspondingly to the second sub-portion 142, and the first recessed portion 1451 is located on one side of the corresponding second sub-portion 142 along the first direction X.

[0102] See some examples. Figure 8 The second recess 1452 is correspondingly disposed with respect to the second sub-part 142, and the second recess 1452 is located on the other side of the corresponding second sub-part 142 along the first direction X. Both the first recess 1451 and the second recess 1452 can be correspondingly disposed with respect to the second sub-part 142. In the correspondingly disposed first recess 1451, second recess 1452, and second sub-part 142, the first recess 1451 and the second recess 1452 are located on opposite sides of the second sub-part 142 along the first direction X. The first recess 1451 and the corresponding second recess 1452 are disposed opposite each other along the first direction X. The size of the first sub-part 141 along the first direction X is larger than the size of the second sub-part 142 along the first direction X. This makes the size of the first sub-part 141 larger along the first direction X, which is beneficial to increasing the contact area between the gate line 160 and the first sub-part 141, and also beneficial to increasing the bonding force between the gate line 160 and the seed layer 140.

[0103] In some embodiments, see Figure 2 and Figure 8 The first sub-surface 1611 has a second sub-surface 1612 on both sides along the first direction X. The second sub-surface 1612 includes a first side L1 away from the seed layer 140. The first sub-surface 1611 has a first side L1 on both sides along the first direction X. The surface of the grid line 160 away from the seed layer 140 is the second surface 162. The junction of the second surface 162 and the battery body 101 is the first side L1. The first side L1 and the seed layer 140 are spaced apart along the first direction X. The distance between the first side L1 and the first sub-part 141 is smaller than the distance between the first side L1 and the second sub-part 142. This results in a smaller distance between the first sub-part 141 and the first side L1, and a smaller area of ​​the second sub-surface 1612 between the first sub-part 141 and the first side L1. This helps to reduce the contact area between the grid line 160 and the battery body 101, and increases the proportion of the contact area between the grid line 160 and the seed layer 140. This helps to reduce the risk of water damage, improve the stability and reliability of the battery, and also reduce resistance and improve conversion efficiency. The principle has been explained and will not be repeated here. In addition, the fact that the size of the first sub-part 141 along the first direction X is larger than the size of the second sub-part 142 along the first direction X also helps to ensure that the size of the grid line 160 along the first direction X is equal everywhere along the extension direction of the grid line 160, thereby improving the uniformity of carrier transport in the grid line 160.

[0104] In some embodiments, see Figure 9The second recess 1452 is correspondingly disposed to the first sub-part 141, and is located on the side of the corresponding first sub-part 141 opposite to the first recess 1451. The first recess 1451 and the second recess 1452 are offset along the first direction X, so that the distribution of the recesses in the second direction Y is more uniform, which is beneficial to improving the uniformity of force between the seed layer 140 and the gate line 160. The size of the first sub-part 141 along the first direction X is equal to the size of the second sub-part 142 along the first direction X, so that the size of the seed layer 140 along the first direction X is almost the same everywhere in the second direction Y, making the carrier transport between the seed layer 140 and the gate line 160 more uniform.

[0105] In some embodiments, see Figure 9 On the side of the seed layer 140 facing the first recess 1451, the distance between the first side L1 and the first sub-part 141 is less than the distance between the first side L1 and the second sub-part 142. On the side of the seed layer 140 facing the second recess 1452, the distance between the first side L1 and the first sub-part 141 is greater than the distance between the first side L1 and the second sub-part 142. Thus, by ensuring that the dimension of the first sub-part 141 along the first direction X is equal to the dimension of the second sub-part 142 along the first direction X, it is beneficial to ensure that the dimension of the gate line 160 along the first direction X is equal everywhere along the extension direction of the gate line 160, thereby improving the uniformity of carrier transport in the gate line 160.

[0106] In some embodiments, see Figure 9 The dimensions of the gate line 160 along the first direction X are uniform throughout its extension direction, which improves the uniformity of carrier transport in the gate line 160. Of course, in other embodiments, the dimensions of the gate line 160 along the first direction X may be at least partially unequal throughout its extension direction.

[0107] In some embodiments, see Figure 10 The surface of the seed layer 140 facing the gate line 160 is the third surface 143, which includes a plurality of sub-convex surfaces 1431. Figure 10 The diagram shows three sub-convex surfaces 1431, which are arranged along the thickness direction of the battery body 101. The sub-convex surfaces 1431 protrude in a direction away from the center of the seed layer 140. There is a third recess 1453 between two adjacent sub-convex surfaces 1431, and the two adjacent sub-convex surfaces 1431 are connected. A portion of the grid line 160 is located in the third recess 1453. In this way, by setting the surface of the seed layer 140 facing the grid line 160 as a plurality of sub-convex surfaces 1431, it is beneficial to increase the area of ​​the surface of the seed layer 140 facing the grid line 160, thereby increasing the contact area between the seed layer 140 and the grid line 160 and improving the bonding force between the seed layer 140 and the grid line 160.

[0108] In some embodiments, see Figure 11 The seed layer 140 has pores 146, and some of the gate lines 160 are located in the pores 146. This allows some of the gate lines 160 to be embedded in the pores 146, which helps to improve the bonding force between the gate lines 160 and the seed layer 140. Specifically, the gate lines 160 can be embedded in the pores 146 near the outer surface of the seed layer 140.

[0109] For example, the porosity of the seed layer 140 is in the range of 5%-15%. This avoids the porosity being too low, which is beneficial to increasing the volume of the gate line 160 extending into the pores 146. In addition, it also avoids the porosity being too high, which would affect the conductivity of the seed layer 140.

[0110] For example, the porosity of the seed layer 140 can be 5%, 7%, 9%, 11%, 13%, 15%, or any value between 5% and 15%.

[0111] For example, the pore size of the pores 146 of the seed layer 140 is in the range of 50nm-200nm. For instance, the pore size of the pores 146 of the seed layer 140 can be 50nm, 100nm, 150nm, 200nm or any value between 50nm and 200nm.

[0112] In some embodiments, see Figure 12 The seed layer 140 includes a first sub-layer 151 and a second sub-layer 152 stacked along a direction away from the battery body 101. Both the first sub-layer 151 and the second sub-layer 152 are in contact with the grid lines 160, with the first sub-layer 151 closer to the battery body 101 and the second sub-layer 152 further away from the battery body 101. Both the first sub-layer 151 and the second sub-layer 152 have pores 146 (… Figure 12 (Not shown in the image) The aperture of the pores 146 in the first sub-layer 151 is larger than that in the second sub-layer 152. This results in a larger aperture of the pores 146 in the first sub-layer 151, leading to a larger volume of the gate line 160 extending into the first sub-layer 151. The bonding force between the first sub-layer 151 and the gate line 160 is further improved. Moreover, the first sub-layer 151 is closer to the passivation layer 130. The improved bonding force between the first sub-layer 151 and the gate line 160 can better alleviate the gate line 160 peeling phenomenon caused by the weak bonding force between the second sub-layer 1612 and the passivation layer 130. In addition, the smaller aperture of the pores 146 in the second sub-layer 152 is beneficial to reducing the porosity of the second sub-layer 152, improving the conductivity of the second sub-layer 152, and facilitating the transport of charge carriers.

[0113] In some embodiments, see Figure 12The seed layer 140 includes a third sub-layer 153, which is located on the side of the first sub-layer 151 opposite to the second sub-layer 152. The third sub-layer 153 is inserted inside the battery body 101, while the first sub-layer 151 and the second sub-layer 152 protrude from the battery body 101. For example, both the first sub-layer 151 and the second sub-layer 152 protrude from the passivation layer 130 so that both the first sub-layer 151 and the second sub-layer 152 are in contact with the gate line 160. The third sub-layer 153 is located in the battery body 101 and penetrates the passivation layer 130 so that the seed layer 140 is in contact with the doped semiconductor layer 120. The aperture of the pores 146 in the first sub-layer 151 is larger than that in the third sub-layer 153. As a result, the third sub-layer 153 and the gate line 160 do not need to contact each other, and the aperture of the pores 146 in the third sub-layer 153 is smaller. This is beneficial to reducing the porosity of the third sub-layer 153, improving the conductivity of the third sub-layer 153, and facilitating the transport of charge carriers.

[0114] In some embodiments, see Figure 13 Seed layer 140 includes a fourth sub-layer 154 and a fifth sub-layer 155, both of which have pores 146. The fifth sub-layer 155 is located between the gate line 160 and the fourth sub-layer 154, and is in contact with the gate line 160. The fourth sub-layer 154 is spaced apart from the gate line 160, and the fifth sub-layer 155 can separate the gate line 160 from the fourth sub-layer 154. Because the fifth sub-layer 155 is in contact with the gate line 160, it has a significant impact on the bonding force between the gate line 160 and the seed layer 140. The aperture of the pores 146 in the fifth sublayer 155 is larger than that in the fourth sublayer 154. Thus, by setting the aperture size of the pores 146 in the fifth sublayer 155 that contact the gate line 160 to be larger, more volume of the gate line 160 extends into the fifth sublayer 155, and the bonding force between the fifth sublayer 155 and the gate line 160 is further improved. In addition, setting the aperture size of the pores 146 in the fourth sublayer 154 that are spaced apart from the gate line 160 to be smaller helps to reduce the porosity in the fourth sublayer 154, improve the conductivity of the fourth sublayer 154, and facilitate the transport of charge carriers.

[0115] In some embodiments, see Figure 14The distance between the side of the grid line 160 closest to the seed layer 140 and the side furthest from the seed layer 140 is the third distance, which is the distance between the first sub-surface 1611 and the second sub-surface 162. The third distance of the grid line 160 gradually decreases from the center to the edge of the grid line 160 along the first direction X. This allows more grid lines 160 to be located above the seed layer 140. In addition, it can reduce the area of ​​the second sub-surface 1612, which is beneficial to reduce the contact area between the grid line 160 and the battery body 101, increase the proportion of the contact area between the grid line 160 and the seed layer 140, reduce the risk of boiling in water, improve the stability and reliability of the battery, and also reduce resistance and improve conversion efficiency. The principle has been explained and will not be repeated here.

[0116] In some embodiments, the gate line 160 and the seed layer 140 protruding from the passivation layer 130 have an overall fan-shaped outer contour along a cross section perpendicular to the second direction Y. Figure 2 ), semicircle, semi-ellipse, triangle ( Figure 3 ), trapezoid ( Figure 4 Any one of the following. The shape of the outer surface of the gate line 160 will affect the contact characteristics between the gate line 160 and the seed layer 140. When the outer contour of the gate line 160 and the seed layer 140 protruding from the passivation layer 130 along the cross section perpendicular to the second direction Y is a regular shape such as a fan shape, a semi-circle, a semi-ellipse, a triangle, or a trapezoid, the stress distribution of the gate line 160 can be more uniform, reducing stress concentration points and thus enhancing adhesion.

[0117] For example, the outer contour of the seed layer 140 along a section perpendicular to the second direction Y is rectangular. Figure 5 ),sector( Figure 3 ), semicircle, semi-ellipse, triangle, trapezoid ( Figure 4 Any one of them.

[0118] For example, see Figure 2 The dimension W1 (i.e. the width of the gate line 160) along the first direction X is in the range of 20μm-70μm. This avoids the gate line 160 being too small along the first direction X, which is beneficial to increasing the contact area between the gate line 160 and the seed layer 140. In addition, it also avoids the gate line 160 being too large along the first direction X, which is beneficial to increasing the arrangement density of the gate line 160 and reducing the shading of the gate line 160 on the light.

[0119] For example, the size of the gate line 160 along the first direction X can be 20μm, 40μm, 45μm, 50μm, 55μm, 60μm, 70μm or any value between 20μm and 70μm.

[0120] For example, see Figure 2The size W2 of the seed layer 140 along the first direction X ranges from 5μm to 30μm. This avoids the seed layer 140 being too small along the first direction X, which is beneficial to increasing the contact area between the gate line 160 and the seed layer 140. In addition, it also avoids the seed layer 140 being too large along the first direction X, which is beneficial to increasing the arrangement density of the seed layer 140.

[0121] For example, the size of the seed layer 140 along the first direction X is 5μm, 10μm, 15μm, 20μm, 25μm, 30μm or any value between 5μm and 30μm.

[0122] In this embodiment, the width of the gate line 160 is set to 40μm-60μm, and the width of the seed layer 140 is set to 10μm-30μm. By reasonably setting the width of the gate line 160 and the width of the seed layer 140, the contact area and coverage effect between the gate line 160 and the seed layer 140 can be ensured.

[0123] For example, the ratio of the maximum distance between the face of the grid line 160 facing away from the seed layer 140 and the second sub-face 1612 along the thickness direction of the battery body 101 to the dimension of the grid line 160 along the first direction X is greater than or equal to 0.3, that is, the aspect ratio of the grid line along 160 is greater than or equal to 0.3, which is beneficial for achieving an angle θ greater than or equal to 20 degrees. For example, this ratio can be 0.3, 0.5, 0.7 or any value greater than 0.3.

[0124] For example, the contact resistance between the grid line 160 and the seed layer 140 is less than or equal to 0.1 Ω·cm². This results in a low contact resistance between the grid line 160 and the seed layer 140. The low-resistance contact interface can significantly reduce the resistance loss of the grid line 160 and improve the fill factor and conversion efficiency of the battery.

[0125] For example, the material of the gate line 160 may include any one or more of the following metals: silver, copper, aluminum, lead, nickel, titanium, tin, etc.

[0126] For example, the material of the seed layer 140 may include any one or more of the following metals: silver, copper, aluminum, lead, nickel, titanium, tin, etc.

[0127] For example, seed layer 140 may include one or both of silver and nickel. Gate line 160 may be made of copper. Both silver and nickel have good adhesion to copper, and when seed layer 140 is silver and / or nickel, the adhesion between gate line 160 and seed layer 140 may be further improved.

[0128] For example, at least one of the grid lines 160 and the seed layer 140 can be formed by means of stencil printing, screen printing, laser transfer, jet printing, gravure printing, low wire diameter non-mesh process, etc.

[0129] The battery body 101 provided in the embodiments of this application will be described below.

[0130] In some embodiments, see Figure 2 The solar cell 100 includes a semiconductor substrate 110, which can provide support for subsequently formed film layers. The semiconductor substrate 110 can be used to receive incident light and generate photogenerated carriers.

[0131] For example, the semiconductor substrate 110 may have two surfaces disposed opposite each other along the thickness direction of the semiconductor substrate 110 (i.e., the third direction Z), at least one of the two surfaces being used to receive sunlight.

[0132] In some embodiments, the semiconductor substrate 110 may be a silicon substrate, and the material of the silicon substrate may include at least one of monocrystalline silicon and polycrystalline silicon. This application uses monocrystalline silicon as an example for illustration.

[0133] For example, the semiconductor substrate 110 can be doped with N-type ions, which can be at least one of phosphorus, arsenic, and antimony. Alternatively, the semiconductor substrate 110 can be doped with P-type ions, which can be at least one of aluminum and boron. This application embodiment uses N-type doping of the semiconductor substrate 110 as an example for illustration.

[0134] In some embodiments, at least a portion of at least one of the surfaces on both sides of the semiconductor substrate 110 in the thickness direction may have a textured structure. The textured structure may be a pyramidal texture, a pitted texture, etc. The textured structure has a low reflectivity to incident light, thereby increasing the absorption and utilization rate of incident light, resulting in a high photoelectric conversion efficiency of the solar cell 100. In other embodiments, at least a portion of at least one of the surfaces on both sides of the semiconductor substrate 110 in the thickness direction may not have a textured structure.

[0135] In some embodiments, see Figure 2 The solar cell 100 includes a doped semiconductor layer 120 disposed on the outer surface of a semiconductor substrate 110. The material of the doped semiconductor layer 120 includes doped polycrystalline silicon, doped amorphous silicon, or doped microcrystalline silicon. The doping type of the doped semiconductor layer 120 is the same as or opposite to the doping type of the semiconductor substrate 110. This application uses doped polycrystalline silicon as an example for illustration.

[0136] In some embodiments, see Figure 2The solar cell 100 includes a passivation layer 130, which is disposed on the side of the doped semiconductor layer 120 facing away from the semiconductor substrate 110. The passivation layer 130 can improve the photoelectric conversion efficiency by reducing the surface recombination rate, thereby increasing the open-circuit voltage and conversion efficiency of the solar cell 100.

[0137] For example, the material of the passivation layer 130 includes one or more of silicon oxide, aluminum oxide, silicon nitride, and silicon oxynitride.

[0138] In some embodiments, the method for preparing the seed layer 140 and the gate line 160 may be as follows: first, the seed layer slurry is placed on the battery body 101, the seed layer 140 burns through the passivation layer 130 and forms a partial alloy (silver-silicon alloy) with the polycrystalline silicon of the doped semiconductor layer 120, a part of the seed layer 140 is located in the passivation layer 130 and is in contact with the doped semiconductor layer 120, and another part of the seed layer 140 is higher than the passivation layer 130.

[0139] In some examples, a seed layer paste is printed on the passivation layer 130, and the battery body 101 with the seed layer paste printed on it is placed in a sintering furnace for high-temperature sintering. After sintering, it is annealed to form a seed layer 140. Using LECO technology, the seed layer 140 is irradiated with a high-intensity laser. The local high temperature generated by the laser will destroy the passivation layer 130, causing the seed layer 140 to burn through the passivation layer 130 and form a partial alloy with the doped semiconductor layer 120. A gate line paste is printed on the surface of the seed layer 140, and then the gate line paste is dried and cured at low temperature in an oxygen-free environment to form a gate line 160. The curing temperature is 300±30℃, and the oxygen-free environment means that the oxygen content in the curing atmosphere is less than 0.3wt%.

[0140] In other examples, a seed layer paste is printed on the passivation layer 130; the battery body 101 with the seed layer paste printed on it is placed in a sintering furnace for high-temperature sintering; after sintering, it is annealed to form a seed layer 140; grid line paste is printed on the surface of the seed layer 140, then the grid line paste is dried and cured at low temperature in an oxygen-free environment to form grid lines 160; wherein, the curing temperature is 300±30℃, and the oxygen-free environment refers to an oxygen content of less than 0.3wt% in the curing atmosphere; finally, using LECO technology, the seed layer 140 is irradiated with a high-intensity laser, and the local high temperature generated by the laser will destroy the passivation layer 130, causing the seed layer 140 to burn through the passivation layer 130 and form a partial alloy with the doped semiconductor layer 120.

[0141] It should be noted that the degree of interfacial reaction between the seed layer 140 and the passivation layer 130 can be controlled by sintering temperature and time. The seed layer 140 can be made to burn through the passivation layer 130 without forming a silver-silicon alloy, or the seed layer 140 can be made to form a silver-silicon alloy with polycrystalline silicon.

[0142] For example, the dimension of the seed layer 140 along the edge of the first direction X along the thickness direction of the battery body 101 ranges from 0.5 μm to 3 μm. For instance, the dimension of the seed layer 140 along the edge of the first direction X along the thickness direction of the battery body 101 can be 0.5 μm, 1 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm, or any value between 0.5 μm and 3 μm.

[0143] The following describes Embodiment 1 and Embodiment 2 provided in this application.

[0144] like Figure 1 and Figure 2 As shown, in the solar cell 100 of Example 1, the seed layer 140 is made of silver, the grid lines 160 covering the surface of the seed layer 140 are made of copper, the angle between the first connecting line AB and the second sub-surface 1612 is 30 degrees, the outer contour of the grid lines 160 and the seed layer 140 protruding from the passivation layer 130 along the cross section perpendicular to the second direction Y is fan-shaped, the width of the grid lines 160 is 50 μm, the width of the seed layer 140 is 20 μm (that is, the width ratio of the grid lines 160 to the seed layer 140 is 2.5), and the contact resistance between the grid lines 160 and the seed layer 140 is less than or equal to 0.1 Ω·cm².

[0145] like Figure 3 As shown, the solar cell 100 of Example 2 has a similar structure to the solar cell 100 of Example 1. The difference is that in Example 2, the angle between the first connecting line AB and the second sub-surface 1612 is 40 degrees. The outer contour of the cross section of the grid line 160 and the seed layer 140 protruding from the passivation layer 130 along the perpendicular second direction Y is triangular. The width of the grid line 160 is 40 μm and the width of the seed layer 140 is 20 μm (that is, the width ratio of the grid line 160 to the seed layer 140 is 2).

[0146] To more clearly illustrate the technical effects of the embodiments of this application, Comparative Example 1 is also provided.

[0147] The solar cell of Comparative Example 1 has a similar structure to the solar cell 100 of Example 1, except that in the solar cell of Comparative Example 1, the angle between the first connecting line AB and the second sub-surface 1612 is 15 degrees, the width of the grid line 160 is 70 μm, and the width of the seed layer 140 is 20 μm (that is, the width ratio of the grid line 160 to the seed layer 140 is 3.5).

[0148] This application also conducted a boiling water test on the solar cells 100 in Examples 1, 2 and Comparative Example 1, and tested their corresponding conversion efficiency, open circuit voltage, short circuit current, fill factor and series resistance. The relevant test results are shown in Table 1.

[0149] Table 1

[0150]

[0151] As shown in Table 1, compared with Comparative Example 1, the grid lines 160 in Embodiments 1 and 2 of this application significantly reduce the risk of detachment due to boiling, resulting in improved conversion efficiency and fill factor of the corresponding solar cells 100, and reduced series resistance. In summary, in the solar cells 100 of this application, by ensuring that the angle θ between the first connecting line AB and the second sub-surface 1612 is greater than or equal to 20 degrees and less than 90 degrees, the stress-bearing area of ​​the grid lines 160 is mainly located above the seed layer 140, which can reduce the risk of boiling, improve the stability and reliability of the cell, reduce resistance, and improve conversion efficiency.

[0152] See Figure 1 The solar cell 100 may have a first direction X, a second direction Y, and a third direction Z, all of which are different. The first direction X and the second direction Y can be any two different directions parallel to the solar cell 100, and the third direction Z can be any direction intersecting a plane parallel to the solar cell 100. For example, the first direction X, the second direction Y, and the third direction Z can be mutually perpendicular. Exemplarily, the first direction X can be the width direction of the solar cell 100, the second direction Y can be the length direction of the solar cell 100, and the third direction Z can be the thickness direction of the solar cell 100. The length, width, and thickness in the embodiments of this application are merely for descriptive convenience and do not imply any limitation on the dimensions. For example, the width can be greater than, equal to, or less than the length. This application embodiment uses the extension of the grid line 160 along the second direction Y as an example for illustration.

[0153] For example, the solar cell 100 may include a heterojunction solar cell (HJT), a back contact cell (BC), a tunnel oxide passivating contact cell (TOPCON), a heterojunction back contact cell (HBC), a hybrid fully passivated back contact cell (hybrid HBC), a passivated emitter back passivated cell (PERC), an interdigitated back contact cell (IBC), etc.

[0154] The photovoltaic modules provided in the embodiments of this application are described below.

[0155] This application provides a photovoltaic module, which includes the solar cell 100 described in the above embodiments. The photovoltaic module may have at least one solar cell 100. This application describes an example where the photovoltaic module has multiple solar cells 100, with the multiple solar cells 100 collectively forming a battery string layer.

[0156] In some embodiments, the photovoltaic module may include a first encapsulation and a second encapsulation located on both sides of the cell string layer, which encapsulate the cell string layer to protect it. The first and second encapsulations may include an encapsulating adhesive layer and a cover plate, with the encapsulating adhesive layer located on the side of the cover plate facing the cell string layer. The cover plate protects the cell string layer, and the encapsulating adhesive layer connects the cover plate and the cell string layer.

[0157] This application provides a photovoltaic system including the photovoltaic modules described in the above embodiments. The advantages of the aforementioned photovoltaic modules are also present in this photovoltaic system, and will not be repeated here. The application fields of the aforementioned photovoltaic system are wide, not limited to photovoltaic power plants, such as ground-mounted power plants, rooftop power plants, and floating power plants, but also including various devices and apparatuses that utilize solar energy for power generation, such as user solar power supplies, solar streetlights, solar cars, and solar buildings. Of course, it is understood that the application scenarios of the photovoltaic system are not limited to these; that is, the photovoltaic system can be applied in all fields that require solar energy for power generation. Taking a photovoltaic power generation system network as an example, the photovoltaic system may include a photovoltaic array, a combiner box, and an inverter. The photovoltaic array may be an array combination of multiple photovoltaic modules; for example, multiple photovoltaic modules can form multiple photovoltaic arrays. The photovoltaic array is connected to the combiner box, which can collect the current generated by the photovoltaic array. The collected current flows through the inverter and is converted into AC power required by the mains power grid before being connected to the mains power grid to achieve solar power supply.

[0158] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0159] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A solar cell, characterized in that, include: Battery body; A seed layer is disposed on the battery body; A grid line is disposed on the side of the seed layer away from the battery body. The surface of the grid line facing the battery body includes a first sub-surface and a second sub-surface. The first sub-surface contacts the seed layer, and the second sub-surface contacts the battery body. Wherein, the ratio of the area of ​​the orthographic projection of the first sub-surface onto the battery body to the area of ​​the orthographic projection of the second sub-surface onto the battery body is greater than or equal to two-sevenths.

2. The solar cell according to claim 1, characterized in that, The grid line is defined to have a first cross section, which is perpendicular to the extension direction of the grid line; in the thickness direction of the battery body, the point on the first cross section that is farthest from the second sub-surface is the first point; in the line where the first cross section contacts the battery body, the point that is farthest from the center of the first cross section in a first direction is the second point, and the first direction is perpendicular to the extension direction of the grid line. The line connecting the first point and the second point is the first connecting line, and the angle between the first connecting line and the second sub-face is greater than or equal to 20 degrees and less than 90 degrees.

3. The solar cell according to claim 1, characterized in that, The ratio of the dimension of the gate line along the first direction to the dimension of the seed layer along the first direction is less than or equal to 3:1, and the first direction is perpendicular to the extension direction of the gate line.

4. The solar cell according to any one of claims 1-3, characterized in that, The seed layer includes a plurality of extension segments spaced apart along the extension direction of the gate line, with a gap between two adjacent extension segments, and a portion of the gate line located in the gap.

5. The solar cell according to claim 4, characterized in that, The plurality of extension segments are arranged in a straight line along the extension direction of the grid line; or... The two adjacent extension segments are staggered along the extension direction of the grid line.

6. The solar cell according to claim 4, characterized in that, The distance between two adjacent extension segments is less than or equal to 100 μm; and / or, The dimension of the extension segment along the extension direction of the grid line is greater than or equal to 30 μm; and / or, The sum of the dimensions of the plurality of extension segments along the extension direction of the grid line is greater than or equal to the sum of the dimensions of all the gaps along the extension direction of the grid line.

7. The solar cell according to any one of claims 1-3, characterized in that, The seed layer has a first recess on one side along the first direction, and a portion of the grid lines are located within the first recess. The first direction is perpendicular to the extension direction of the grid lines.

8. The solar cell according to claim 7, characterized in that, The seed layer has a second recess on the other side along the first direction, and a portion of the grid lines are located within the second recess.

9. The solar cell according to claim 8, characterized in that, The seed layer includes a first sub-section and a second sub-section arranged alternately along the extension direction of the gate line. The first recessed portion is correspondingly disposed to the second sub-section, and the first recessed portion is located on one side of the corresponding second sub-section.

10. The solar cell according to claim 9, characterized in that, The second recessed portion is provided correspondingly to the second sub-part, and the second recessed portion is located on the other side of the corresponding second sub-part. The dimension of the first sub-part along the first direction is greater than the dimension of the second sub-part along the first direction.

11. The solar cell according to claim 10, characterized in that, The second sub-face includes a first side away from the seed layer, the first side and the seed layer are spaced apart along the first direction, and the distance between the first side and the first sub-face is less than the distance between the first side and the second sub-face.

12. The solar cell according to claim 9, characterized in that, The second recessed portion is provided corresponding to the first sub-part, and the second recessed portion is located on the side of the corresponding first sub-part that is away from the first recessed portion; The dimension of the first sub-part along the first direction is equal to the dimension of the second sub-part along the first direction.

13. The solar cell according to claim 12, characterized in that, The second sub-face includes a first edge away from the seed layer, and the first edge and the seed layer are spaced apart along the first direction; On the side of the seed layer facing the first recess, the distance between the first edge and the first sub-part is less than the distance between the first edge and the second sub-part. On the side of the seed layer facing the second recess, the distance between the first edge and the first sub-part is greater than the distance between the first edge and the second sub-part.

14. The solar cell according to any one of claims 1-3, characterized in that, The dimension of the gate line along the first direction is equal everywhere along the extension direction of the gate line, and the first direction is perpendicular to the extension direction of the gate line.

15. The solar cell according to any one of claims 1-3, characterized in that, The surface of the seed layer facing the grid line includes a plurality of sub-convex surfaces, which are arranged along the thickness direction of the battery body. The sub-convex surfaces protrude in a direction away from the center of the seed layer, and a third recess is provided between two adjacent sub-convex surfaces, with a portion of the grid line located within the third recess.

16. The solar cell according to any one of claims 1-3, characterized in that, The seed layer has pores, and some of the grid lines are located in the pores.

17. The solar cell according to claim 16, characterized in that, The seed layer includes a first sub-layer and a second sub-layer stacked along a direction away from the battery body, and both the first sub-layer and the second sub-layer are in contact with the grid lines; Both the first sublayer and the second sublayer have the pores, and the pore diameter in the first sublayer is larger than the pore diameter in the second sublayer.

18. The solar cell according to claim 17, characterized in that, The seed layer includes a third sub-layer, which is located on the side of the first sub-layer away from the second sub-layer. The third sub-layer is inserted into the battery body, and the first and second sub-layers protrude from the battery body. The pore diameter in the third sublayer is smaller than the pore diameter in the first sublayer.

19. The solar cell according to claim 16, characterized in that, The seed layer includes a fourth sub-layer and a fifth sub-layer, both of which have the pores. The fifth sub-layer is located between the gate line and the fourth sub-layer, and is in contact with the gate line. The fourth sub-layer is spaced apart from the gate line. The pore diameter in the fifth sublayer is larger than the pore diameter in the fourth sublayer.

20. The solar cell according to any one of claims 1-3, characterized in that, The distance between the face of the gate line near the seed layer and the face of the gate line away from the seed layer is the third distance. The third distance of the gate line gradually decreases from the center to the edge of the gate line along the first direction. The first direction is perpendicular to the extension direction of the gate line.

21. The solar cell according to any one of claims 1-3, characterized in that, The size of the gate line along the first direction ranges from 20μm to 70μm; and / or, The seed layer has a size range of 5μm-30μm along the first direction; and / or, The ratio of the maximum distance between the face of the grid line away from the seed layer and the second sub-face along the thickness direction of the battery body to the dimension of the grid line along the first direction is greater than or equal to 0.3; and / or, The contact resistance between the grid line and the seed layer is less than or equal to 0.1 Ω·cm²; The first direction is perpendicular to the extension direction of the gate line.

22. A photovoltaic module, characterized in that, Includes the solar cell described in any one of claims 1-21.

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