Solar cell and photovoltaic module

Abstract

The embodiment of the invention provides a solar cell and a photovoltaic module. The solar cell comprises a cell body and a grid line structure arranged on the cell body, wherein the grid line structure comprises an electric connection part and a current collection grid line; wherein in the extension direction of the current collection grid line, the current collection grid line comprises an overlapping part which is overlapped with the electric connection part, and a plurality of fluctuating structures are arranged on one side, far away from the battery body, of the overlapping part. In the embodiment of the invention, the fluctuating structure can provide a plurality of contacts with relatively high heights for the test probe, and the connection reliability between the test probe and the fluctuating structure is improved, so that the accuracy of performing an electrical performance test on the solar cell can be improved.

Description

Technical Field

[0001] The present application belongs to the field of photovoltaic processing technology, and specifically relates to a solar cell and a photovoltaic module. Background Art

[0002] As a clean energy, solar energy has received great attention in recent years. Photovoltaic manufacturers and researchers are striving to continuously improve the performance and quality of photovoltaic modules through process technology optimization and production process improvement. Among them, electrical performance testing of solar cells is a necessary step in confirming the performance quality of photovoltaic modules. In specific applications, test probes are usually used to contact the electrical connection parts of solar cells to test the electrical performance of solar cells.

[0003] However, in the existing technology, it is easy for the test probe to have poor contact with the electrical connection part of the solar cell. Therefore, in the process of testing the electrical performance of the solar cell, it is easy to cause test errors due to the inadequate pressing of the connection part between the test probe and the solar cell, which greatly reduces the accuracy of the solar cell when performing electrical performance testing. Summary of the invention

[0004] The present application aims to provide a solar cell and a photovoltaic module to solve the problem of low accuracy of existing solar cells when conducting electrical performance tests.

[0005] In order to solve the above technical problems, this application is implemented as follows:

[0006] In a first aspect, the present application discloses a solar cell, the solar cell comprising: a cell body, a grid line structure arranged on the cell body, the grid line structure comprising an electrical connection portion and a collector grid line;

[0007] Wherein, along the extension direction of the collector grid line, the collector grid line includes an overlapping portion overlapping with the electrical connection portion, and a plurality of undulating structures are arranged on a side of the overlapping portion away from the battery body.

[0008] Optionally, along the extension direction of the collector grid line, the electrical connection portion has a central region and an edge region, and a thickness of the central region is greater than a thickness of the edge region.

[0009] Optionally, the width of the electrical connection portion along the extension direction of the collector grid line is a first width, the width of the edge region along the extension direction is a second width, and the ratio of the second width to the first width is: 1%-15%.

[0010] Optionally, the undulation degree of the undulating structure located in the central area is greater than the undulation degree of the undulating structure located in the edge area.

[0011] Optionally, the portion of the collector grid line outside the overlapping portion is a first body portion, and the undulation degree of the undulating structure is greater than that of the first body portion;

[0012] And / or, the portion of the electrical connection portion that does not overlap with the collector grid line is a second body portion, and the undulation degree of the undulating structure is greater than that of the second body portion.

[0013] Optionally, the number of the electrical connection portions is multiple. Along the extending direction of the collector grid line, the electrical connection portion located at the edge of the battery body is an edge electrical connection portion, and the electrical connection portion located at the center of the battery body is a center electrical connection portion;

[0014] The undulating structure of the overlapping portion between the collector grid line and the edge electrical connection portion has a first undulation degree, and the undulating structure of the overlapping portion between the collector grid line and the center electrical connection portion has a second undulation degree;

[0015] The first undulation degree is less than the second undulation degree.

[0016] Optionally, the electrical connection portions are intermittently arranged along a direction perpendicular to the extending direction of the collector grid line.

[0017] Optionally, the collector grid line is located above the electrical connection portion.

[0018] Optionally, the collector grid line is located above the electrical connection portion. The height of the portion of the electrical connection portion overlapping with the collector grid line is a first height, and the height of the portion of the electrical connection portion not overlapping with the collector grid line is a second height. The first height is lower than the second height.

[0019] Optionally, multiple undulating structures are arranged adjacent to each other in sequence along the extending direction of the collector grid line.

[0020] In a second aspect, the present application also discloses a photovoltaic module. The photovoltaic module includes a plurality of battery strings, and the battery strings include the solar cell according to any one of the above.

[0021] An electrical connection line, which is electrically connected to the grid line structure;

[0022] The electrical connection line is disposed on the grid line structure, and the electrical connection line covers at least a part of the grid line structure.

[0023] Optionally, the electrical connection line is electrically connected to the grid line structure through a bonding material, and the bonding material is partially embedded in the undulating structure.

[0024] In the embodiment of the present application, the overlapping portion where the collector grid line overlaps with the electrical connection portion can be used to contact a test probe, so as to perform an electrical performance test on the solar cell through the test probe. Since a plurality of undulating structures are provided on the side of the overlapping portion away from the battery body, the undulating structures can provide a plurality of contacts with relatively high heights for the test probe, improving the connection reliability with the test probe. Therefore, the accuracy of the electrical performance test on the solar cell can be improved.

[0025] Additional aspects and advantages of the present invention will be given in part in the following description, become apparent in part from the following description, or be understood through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The above and / or additional aspects and advantages of the present invention will become apparent and be readily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0027] Figure 1 is a schematic structural diagram of a solar cell according to an embodiment of the present application;

[0028] Figure 2 is Figure 1 a schematic structural diagram of the solar cell shown from another angle.

[0029] Reference numerals: 10 - battery body, 11 - electrical connection portion, 12 - collector grid line, X - extending direction, 121 - undulating structure, 122 - edge region of the overlapping portion, 123 - first body portion. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0030] Embodiments of the present invention will be described in detail below. Examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary only for explaining the present invention and should not be construed as limiting the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts fall within the scope of protection of the present application.

[0031] The terms "first" and "second" in the description and claims of the present application may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise specified, the meaning of "a plurality" is two or more. In addition, "and / or" in the description and claims means at least one of the connected objects, and the character " / " generally indicates an "or" relationship between the related objects before and after.

[0032] In the description of the present invention, it should be understood that the orientation or positional relationships indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. are based on the orientation or positional relationships shown in the drawings. These are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present invention.

[0033] In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "mounted", "connected", and "coupled" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0034] Referring to Figure 1 , a schematic structural diagram of a solar cell according to an embodiment of the present application is shown. Referring to Figure 2 , Figure 1 shows a schematic structural diagram of the solar cell shown from another angle. As shown in Figure 1 and Figure 2 , the solar cell may specifically include: a cell body 10, and a grid line structure disposed on the cell body 10. The grid line structure may include an electrical connection portion 11 and a collector grid line 12.

[0035] In some embodiments of the present application, along the extension direction X of the collector grid line 12, the collector grid line 12 may include an overlapping portion that overlaps with the electrical connection portion 11, and a plurality of undulating structures 121 are provided on a side of the overlapping portion away from the cell body 10.

[0036] In the embodiments of the present application, the overlapping portion where the collector grid line 12 overlaps with the electrical connection portion 11 can be used to contact a test probe, so as to perform an electrical performance test on the solar cell through the test probe. Since a plurality of undulating structures 121 are provided on a side of the overlapping portion away from the cell body 10, the undulating structures 121 can provide a plurality of contacts with relatively high heights for the test probe, improving the connection reliability with the test probe. Thus, the accuracy of the electrical performance test on the solar cell can be improved.

[0037] In a specific application, along the direction perpendicular to the extending direction of the collector grid line 12, the width of the electrical connection portion 11 is generally wider than the width of the collector grid line 12. Therefore, the overlapping position of the electrical connection portion 11 and the collector grid line 12 usually serves as a test point for the electrical performance test of the solar cell. By providing the undulating structure 121 at the overlapping position of the collector grid line 12 and the electrical connection portion 11, the accuracy of the test can be maximally improved. In addition, since the height of the overlapping region of the electrical connection portion 11 and the collector grid line 12 is greater than the height of the non-overlapping region, higher contacts can be further provided to improve the accuracy of the test.

[0038] In practical applications, through the multiple higher contacts provided by the undulating structure 121, the pressing abnormality of the solar cell caused by the height difference between the P / N regions, the height difference of the pads, printing abnormalities, the advancing error of the test probe row, etc. can be improved, and the accuracy of the electrical performance test of the solar cell can be enhanced.

[0039] In addition, during the series soldering at the component end, the undulating structure 121 increases the surface area of the overlapping portion, thereby increasing the contact area between the electrical connection line (such as a solder tape) and the grid line structure, and enhancing the connection strength between the electrical connection line and the solar cell.

[0040] In a specific application, the grid line structure can be formed on the surface of the battery body 10 by a printing process. That is, by printing a paste on the surface of the battery body 10, the electrical connection portion 11 and the collector grid line 12 can be formed.

[0041] In some embodiments of the present application, as Figure 1 shown, along the extending direction X of the collector grid line 12, the electrical connection portion 11 has a central region and an edge region, and the thickness of the central region is greater than the thickness of the edge region. In practical applications, since the height of the edge region of the electrical connection portion 11 is relatively low, this region has little influence on the paste filling amount and ink penetration amount during the printing of the collector grid line 12, and no obvious periodic undulating structure 121 will be formed. In this way, the continuity of the collector grid line 12 can be improved, and the sudden change in height or line width of the collector grid line 12 can be avoided. Thus, the resistance of the collector grid line 12 can be relatively uniform, and the current transmission effect of the collector grid line 12 can be enhanced.

[0042] As Figure 1 shown, the width of the electrical connection portion 11 along the extending direction X of the collector grid line 12 is the first width W1, the width of the edge region along the extending direction X is the second width W2, and the ratio of the second width W2 to the first width W1 is: 1% - 15%, so as to keep a reasonable proportion between the width of the edge region of the electrical connection portion 11 and the overall width of the electrical connection portion 11, and improve the continuity of the collector grid line 12 provided above the electrical connection portion 11.

[0043] Exemplarily, the ratio of the second width W2 to the first width W1 can be any one of 1%, 3%, 6%, 10%, or 15%. The embodiments of the present application do not specifically limit the ratio of the second width W2 to the first width W1.

[0044] In some embodiments of the present application, the undulation degree of the undulation structure 121 located in the central region is greater than that of the undulation structure 121 located in the edge region. In this way, during the process of forming the undulation structure 121 by printing, affected by the fluidity of the slurry, it is not easy to form an undulation structure 121 with a large undulation degree in the edge region. By setting the undulation degree of the undulation structure 121 in the edge region to be smaller, it is beneficial to the processing of the undulation structure 121.

[0045] In practical applications, as Figure 1 shown, the undulation structure 121 can also be only arranged at a position opposite to the central region of the electrical connection part 11 on the overlapping part, and the undulation structure 121 does not need to be arranged in the edge region 122 of the overlapping part.

[0046] Optionally, as Figure 1 shown, the part of the collector grid line 12 outside the overlapping part is the first body part 123, and the undulation degree of the undulation structure 121 is greater than that of the first body part 123. In this way, a contact with a higher height can be provided through the undulation structure 121 to achieve reliable contact with the test probe. At the same time, since the undulation degree of the first body part 123 is smaller, the collector grid line 12 can maintain good continuity, avoid a sudden change in height of the collector grid line 12, and improve the current collection effect of the collector grid line 12.

[0047] And / or, the part of the electrical connection part 11 that does not overlap with the collector grid line 12 is the second body part, and the undulation degree of the undulation structure 121 is greater than that of the second body part. In a specific application, by setting the undulation degree of the second body part to be smaller, it is not only convenient for the printing process of the electrical connection part 11, but also, during the series soldering process of the solar cell, the electrical connection wire located above the electrical connection part 11, such as the solder tape, has good continuity, avoiding sudden changes in height or line width of the solder tape, thereby reducing the possibility of solder tape breakage or false soldering.

[0048] In some embodiments of the present application, the number of the electrical connection portions 11 is plural. Along the extending direction X of the current collecting grid line 12, the electrical connection portions 11 located at the edge of the battery body 10 are edge electrical connection portions, and the electrical connection portions 11 located at the center of the battery body 10 are central electrical connection portions; the undulating structure 121 of the overlapping portion of the current collecting grid line 12 and the edge electrical connection portion has a first undulating degree, and the undulating structure 121 of the overlapping portion of the current collecting grid line 12 and the central electrical connection portion 11 has a second undulating degree; the first undulating degree is less than the second undulating degree.

[0049] In a specific application, since the undulating degree of the undulating structure 121 of the overlapping portion of the current collecting grid line 12 and the central electrical connection portion is relatively high, correspondingly, the contacts that the undulating structure 121 overlapping with the central electrical connection portion can provide are also relatively high, so as to facilitate the contact between the undulating structure 121 and the test probe and improve the accuracy of the electrical performance test of the solar cell. At the same time. Since the undulating degree of the undulating structure 121 of the overlapping portion of the current collecting grid line 12 and the edge electrical connection portion is relatively small, it is beneficial to reduce the influence of the setting of the undulating structure 121 on the edge strength of the solar cell and reduce the risk of edge cracking of the solar cell during subsequent series soldering.

[0050] In some embodiments of the present application, the electrical connection portions 11 are intermittently arranged along a direction perpendicular to the extending direction of the current collecting grid line. The electrical connection portions 11 can be distributed at intervals on the surface of the battery body 10, that is, at this time, the electrical connection portions 11 can be solder pads, end wires near the edge of the solar cell, or thickened segments overlapping with the current collecting grid line 12, as long as they can be electrically connected to the current collecting grid line 12 and can be electrically connected to an electrical connection wire, such as a solder strip. The current collecting grid line 12 can be continuously arranged at the overlapping portion with the electrical connection portion 11 along the extending direction X. Compared with the continuously arranged electrical connection portions 11, the electrical connection portions 11 are intermittently arranged, and the contact area between the electrical connection portions 11 and the electrical connection wire of the solar cell is greatly reduced. Therefore, setting the undulating structure 121 at the overlapping portion can make up for the loss of the reduced contact area caused by the intermittent arrangement of the electrical connection portions 11, and the technical effect of providing higher contacts can be further reflected.

[0051] Optionally, the current collecting grid line 12 can be located above the electrical connection portion 11. In actual application, when the current collecting grid line 12 is located above the electrical connection portion 11, the electrical connection portion 11 can be prepared on the battery body 10 first, and then the current collecting grid line 12 can be prepared on the electrical connection portion 11. In this way, the printing accuracy of the current collecting grid line 12 of the solar cell overlapping on the electrical connection portion 11 can be improved to a large extent, and the probability that the undulating structure 121 is located at the center position of the solder pad can be increased, and the probability of generating test pressing errors can be reduced.

[0052] Optionally, the collector grid line 12 is located above the electrical connection part 11. The height of the part of the electrical connection part 11 overlapping with the collector grid line 12 is the first height, and the height of the part of the electrical connection part 11 not overlapping with the collector grid line 12 is the second height, and the first height is lower than the second height. In a specific application, by reducing the height of the part of the electrical connection part 11 overlapping with the collector grid line 12, the contact area between the collector grid line 12 and the electrical connection part 11 can be increased, the bonding force between the collector grid line 12 and the electrical connection part 11 can be improved, and the risk of the collector grid line 12 falling off can be reduced.

[0053] Optionally, as Figure 1 shown, a plurality of undulating structures 121 are arranged adjacent to each other in sequence along the extension direction X of the collector grid line 12. In this way, the regularity of the arrangement of the undulating structures 121 can be improved, and then the consistency of the undulating degree on the overlapping part can be improved, and the pressing accuracy during the testing process can be improved. At the same time, the processing convenience of the undulating structures 121 can be greatly improved.

[0054] It should be noted that in practical applications, the plurality of undulating structures 121 can also be distributed in a direction intersecting with the extension direction X of the collector grid line 12, and the embodiments of the present application do not make specific limitations on the distribution manner of the plurality of undulating structures 121.

[0055] Optionally, the width of the undulating structure 121 along the extension direction X of the collector grid line 12 is 40 - 80 μm; and / or, the height variation range of the undulating structure 121 is 0.1 - 10 μm. In a specific application, considering the widths and heights of the electrical connection part 11 and the collector grid line 12 on the solar cell, setting the width and height of the undulating structure 121 within the above ranges will not be too large to exceed the grid line structure, nor too small to affect the technical effect of the undulating structure 121 providing pressing contacts. In addition, setting the width and height of the undulating structure 121 within the above ranges can better adapt to the existing process, and reduce the processing difficulty and processing cost of the undulating structure 121.

[0056] It should be noted that the height variation range of the undulating structure 121 can also be set according to requirements, and the embodiments of the present application do not make specific limitations on this.

[0057] In practical applications, by way of example, the width and height of the undulating structure 121 can be adjusted by adjusting the process equipment parameters. When preparing the current collecting grid line 12 by screen printing, due to the height mutation in the area of the electrical connection part 11, the screen distance changes, resulting in insufficient filling of the paste in the mesh holes in this area, and there is a blockage of the screen wires when the squeegee passes through the screen wires. Even if there is paste filling on both sides, the ink penetration amount in this area is still relatively low, resulting in a trough; as the squeegee advances, when there is no screen wire blockage, the paste gradually accumulates, and the height of the printed line type gradually increases to form a peak until a trough appears when the next screen wire blocks; therefore, the size of the period T of the periodic undulating structure 121 is controlled by adjusting the screen mesh number, and by adjusting screen parameters such as yarn thickness, film thickness, and line width, as well as printing parameters such as printing speed, squeegee pressure, squeegee angle, and screen distance, its undulating height can be controlled. By way of another example, the width and height of the undulating structure can be controlled by adjusting the ratio of the screen printing paste and changing the fluidity of the paste. Adjusting the height and width of the undulating structure 121 can also be achieved by other process methods, and the embodiments of the present application do not make specific limitations in this regard.

[0058] Optionally, the undulating structure 121 has a highest point. On both sides of the undulating structure 121 along the extending direction X of the current collecting grid line 12 at the highest point are a first side and a second side, and the inclination degrees of the first side and the second side are different. Generally, the current collecting grid line 12 can be printed along the extending direction X. Affected by the fluidity of the paste, along the printing direction, the cross-sectional shape of the undulating structure 121 is prone to periodic changes of "trough - slow increase in height - peak - rapid decrease in height - trough", so that the inclination degrees of both sides of the undulating structure 121 are different. Therefore, when the inclination degrees of the first side and the second side of the undulating structure 121 are different, it is beneficial to the processing of the undulating structure 121.

[0059] It should be noted that when the process permits, it is also feasible that the inclination degrees of both sides of the undulating structure 121 are the same, and the embodiments of the present application do not make specific limitations on whether the inclination degrees of both sides of the undulating structure 121 are the same.

[0060] In some embodiments of the present application, when the current collecting grid line 12 is arranged above the electrical connection part 11, the side of the electrical connection part 11 away from the battery body 10 is the first surface, and the distance between the lowest position of the undulating structure 121 and the first surface is 1 - 5 μm. In a specific application, when the distance between the lowest position of the undulating structure 121 and the first surface is too close, it may cause virtual printing of the current collecting grid line 12. If the distance between the lowest position of the undulating structure 121 and the first surface is too far, the height of the undulating structure 121 is too high, affecting the continuity of the undulating structure 121.

[0061] In summary, the solar cell described in the embodiments of the present application has at least the following advantages:

[0062] In the embodiments of the present application, the overlapping portion where the collector grid line overlaps with the electrical connection portion can be used to contact a test probe, so as to perform an electrical performance test on the solar cell through the test probe. Since a plurality of undulating structures are provided on the side of the overlapping portion away from the battery body, the undulating structures can provide a plurality of contacts with relatively high heights for the test probe, improving the connection reliability with the test probe. Thus, the accuracy of the electrical performance test on the solar cell can be improved.

[0063] The embodiments of the present application further provide a photovoltaic module, which may specifically include a plurality of battery strings. The battery strings may include the solar cell described in any of the above embodiments; and electrical connection lines, which are electrically connected to the grid line structure. The electrical connection lines are disposed on the grid line structure, and the electrical connection lines at least cover a part of the grid line structure to collect the current transmitted on the grid line structure through the electrical connection lines. Among them, the electrical connection line is a conductive interconnecting member and may be a wire such as a solder ribbon that can achieve conductive connection.

[0064] It should be noted that in the embodiments of the present application, the structure of the solar cell is the same as that of the solar cell described in any of the above embodiments, and its beneficial effects are also similar, which will not be limited herein.

[0065] Furthermore, the overlapping portion where the collector grid line of the solar cell overlaps with the electrical connection portion can be used to contact the electrical connection line. Since a plurality of undulating structures are provided on the side of the overlapping portion away from the battery body, the undulating structures can provide a plurality of contacts with relatively high heights for the electrical connection line, increasing the contact area with the electrical connection line. Thus, the reliability of the string soldering of the solar cell can be improved.

[0066] In some alternative embodiments of the present application, the electrical connection line is electrically connected to the grid line structure through a bonding material, and the bonding material is partially embedded in the undulating structure to increase the contact area with the undulating structure and improve the connection reliability between the bonding material and the undulating structure.

[0067] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "schematic embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0068] Although embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the claims and their equivalents.

Claims

1. A solar cell, characterized in that: The solar cell comprises: a cell body, a grid line structure arranged on the cell body, the grid line structure comprising an electrical connection portion and a collector grid line; Wherein, along the extension direction of the collector grid line, the collector grid line includes an overlapping portion overlapping with the electrical connection portion, and a plurality of undulating structures are arranged on a side of the overlapping portion away from the battery body.

2. The solar cell according to claim 1, characterized in that Along the extending direction of the collector grid line, the electrical connection portion has a central region and an edge region, and the thickness of the central region is greater than the thickness of the edge region.

3. The solar cell according to claim 2, characterized in that: The width of the electrical connection portion along the extending direction of the collector grid line is a first width, the width of the edge region along the extending direction is a second width, and the ratio of the second width to the first width is: 1%-15%.

4. The solar cell according to claim 2, characterized in that: The undulation degree of the undulating structure located in the central area is greater than the undulation degree of the undulating structure located in the edge area.

5. The solar cell according to claim 1, characterized in that: The portion of the collector grid line other than the overlapping portion is a first main body portion, and the undulation degree of the undulating structure is greater than the undulation degree of the first main body portion; And / or, the portion of the electrical connection portion that does not overlap with the collector grid line is a second body portion, and the undulation degree of the undulating structure is greater than the undulation degree of the second body portion.

6. The solar cell according to claim 1, characterized in that There are multiple electrical connection parts, and along the extension direction of the collector grid line, the electrical connection parts located at the edge of the battery body are edge electrical connection parts, and the electrical connection parts located at the center of the battery body are center electrical connection parts; The undulating structure of the overlapping portion of the collector grid line and the edge electrical connection portion has a first undulation degree, and the undulating structure of the overlapping portion of the collector grid line and the central electrical connection portion has a second undulation degree; The first fluctuation degree is smaller than the second fluctuation degree.

7. The solar cell according to claim 1, characterized in that The electrical connection portion is intermittently arranged along a direction perpendicular to the extending direction of the collector grid line.

8. The solar cell according to claim 1 or 7, characterized in that: The collector grid line is located above the electrical connection portion.

9. The solar cell according to claim 1 or 7, characterized in that: The collector gate line is located above the electrical connection part, the height of the portion of the electrical connection part overlapping with the collector gate line is a first height, and the height of the portion of the electrical connection part not overlapping with the collector gate line is a second height, and the first height is lower than the second height.

10. The solar cell according to claim 1, characterized in that: The plurality of undulating structures are arranged adjacent to each other in sequence along the extending direction of the collector grid lines.

11. A photovoltaic module, characterized in that: The photovoltaic assembly comprises a plurality of battery strings, and the battery strings comprise the solar cell according to any one of claims 1 to 10; An electrical connection line, the electrical connection line being electrically connected to the gate line structure; The electrical connection line is disposed on the gate line structure, and the electrical connection line at least covers a portion of the gate line structure.

12. The photovoltaic module according to claim 11, characterized in that: The electrical connection line is electrically connected to the gate line structure through a bonding material, and the bonding material is partially embedded in the undulating structure.

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