Solar cell and photovoltaic module

Abstract

The invention provides a solar cell and a photovoltaic module. The solar cell comprises a semiconductor substrate. The collector grid lines are arranged on the semiconductor substrate and extend in the first direction, and the surfaces of the collector grid lines are provided with a plurality of protruding parts. The protruding parts are distributed at intervals in the first direction. Wherein at least one current collection grid line is provided with at least one test section, the surface of the current collection grid line in the test section is provided with a plurality of contact platforms which are distributed at intervals along the first direction, and the contact platforms are formed at the tops of at least part of convex parts of the current collection grid line in the test section. According to the solar cell disclosed by the invention, the test sections with the plurality of contact platforms are arranged on the collector grid lines, so that the contact tightness between the collector grid lines and the probes can be enhanced, the stable detection of the solar cell is realized, and the accuracy of the test result of the solar cell is further improved.

Description

Technical Field

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

[0002] A solar cell is a semiconductor device that converts light energy into electrical energy. It uses the photoelectric effect to directly convert solar radiation energy into electrical energy.

[0003] Solar cells need to undergo electrical performance tests during and after their preparation, such as open circuit voltage, short circuit current, maximum output power, fill factor, and conversion efficiency, in order to evaluate their performance and quality.

[0004] However, when there is a problem in the electrical contact between the probe and the cell, the test result may be inaccurate. Summary of the invention

[0005] In view of the above problems, embodiments of the present disclosure provide a solar cell and a photovoltaic module.

[0006] One aspect of the present disclosure provides a solar cell, comprising: a semiconductor substrate. A plurality of collector grid lines extending along a first direction are arranged on the semiconductor substrate, and a plurality of protrusions are provided on the surface of the collector grid lines. The protrusions are spaced apart along the first direction. At least one collector grid line has at least one test section, and the surface of the collector grid line in the test section has a plurality of contact platforms spaced apart along the first direction, and the tops of at least some of the protrusions of the collector grid line in the test section form contact platforms.

[0007] According to an embodiment of the present disclosure, the contact platform has a first surface away from the semiconductor substrate, and the solar cell further includes: a doped semiconductor layer disposed between the semiconductor substrate and the collector grid line. An alloy layer is formed between the collector grid line and the doped semiconductor layer, and the distance between the first surface and the alloy layer is 10 μm to 40 μm.

[0008] According to an embodiment of the present disclosure, the collector grid line includes a first collector grid line and a second collector grid line with opposite polarities and alternately spaced along a second direction, and the second direction intersects with the first direction. The solar cell also includes: a plurality of terminal lines with opposite polarities, extending along the second direction and spaced along the first direction. And a first welding structure arranged on the terminal lines. The first collector grid line close to the edge of the solar cell along the first direction is electrically connected to the first welding structure through the terminal line of the same polarity, and is isolated at the terminal line of different polarity. At least one collector grid line directly electrically connected to the terminal line has a test segment, or at least one collector grid line directly electrically connected to the first welding structure has a test segment.

[0009] According to an embodiment of the present disclosure, the solar cell further comprises: a second welding structure disposed on the straight line where the end line is located and not electrically connected to the end line, the second welding structure being electrically connected to a collector grid line of the same polarity away from an edge of the solar cell extending along the first direction, the width of the second welding structure along the second direction being smaller than the width of the first welding structure along the second direction. The distance between the test section and at least one of the corresponding second welding structure, the first welding structure and the end line is less than or equal to 30 mm.

[0010] According to an embodiment of the present disclosure, the solar cell further includes: an auxiliary test electrode, which is arranged at the intersection of the terminal line and at least one electrically connected collector grid line, and is electrically connected to the terminal line. The width of the auxiliary test electrode along the second direction is smaller than the width of the first welding structure along the second direction, and is larger than the width of the collector grid line, and the length of the auxiliary test electrode along the first direction is larger than the width of the terminal line. The number of contact platforms in a single test segment on the collector grid line where the auxiliary test electrode is arranged is larger than the number of contact platforms in a single test segment on the collector grid line where the auxiliary test electrode is not arranged.

[0011] According to an embodiment of the present disclosure, each test section is located on the same side of the straight line where the corresponding first welding structure is located.

[0012] According to an embodiment of the present disclosure, with a line passing through the geometric center of the solar cell and extending along the second direction as the central axis, a test segment arranged on the first side of the central axis is offset along the first direction relative to the straight line where the corresponding first welding structure is located, and a test segment arranged on the second side of the central axis is offset along the first direction relative to the straight line where the corresponding first welding structure is located, and the offset distances of the test segments distributed on the first side and the second side of the same collector grid are equal and the offset directions are opposite, and the first side and the second side are opposite sides.

[0013] According to an embodiment of the present disclosure, the test segments on the collector grid lines electrically connected to the terminal lines constitute multiple first test point sequences along the second direction. The test segments on the collector grid lines not electrically connected to the terminal lines constitute multiple second test point sequences along the second direction. The number of the first test point sequences is different from the number of the second test point sequences, and the spacing between each first test point sequence is greater than the spacing between each second test point sequence.

[0014] According to an embodiment of the present disclosure, a plurality of first test segments spaced apart along a first direction are respectively arranged on each first collector grid line, and the plurality of first test segments constitute a plurality of third test point sequences spaced apart along a second direction. A plurality of second test segments spaced apart along a first direction are respectively arranged on each second collector grid line, and the plurality of second test segments constitute a plurality of fourth test point sequences spaced apart along a second direction. The third test point sequence is not collinear with the fourth test point sequence.

[0015] According to an embodiment of the present disclosure, the first test point sequence is collinear with the corresponding terminal line, and the second test point sequence is not collinear with the first test point sequence.

[0016] According to an embodiment of the present disclosure, a plurality of contact platforms formed in the test section are located on top of a plurality of continuously distributed protrusions, and at most one contact platform is formed on the top of each protrusion.

[0017] According to an embodiment of the present disclosure, the height of the contact platforms located at two ends of the test section is greater than the height of the contact platforms located at other than two ends of the test section.

[0018] Another aspect of the present disclosure provides a photovoltaic module, including: a plurality of solar cells connected by conductive interconnects, the conductive interconnects covering a portion of each solar cell along a second direction. An encapsulation layer, used to cover the surface of the plurality of solar cells. A cover plate, used to cover the surface of the encapsulation layer away from the plurality of solar cells. At least one test section is formed on the area of ​​at least one collector grid line not covered by the conductive interconnects, the collector grid line extends along a first direction, the test section includes a plurality of contact platforms spaced apart along the first direction, the contact platforms are used to contact with a probe to perform an electrical performance test on the photovoltaic module, and the second direction intersects with the first direction.

[0019] The present disclosure can enhance the closeness of contact between the collector grid lines and the probes by setting a test section with multiple contact platforms on each collector grid line, thereby achieving stable detection of solar cells and further improving the accuracy of solar cell test results. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The above contents and other purposes, features and advantages of the present disclosure will become more apparent through the following description of the embodiments of the present disclosure with reference to the accompanying drawings, in which:

[0021] Figure 1A A partial planar structure diagram of a solar cell according to an embodiment of the present disclosure is schematically shown; Figure 1B A comparison diagram schematically shows a planar structure of a test section according to an embodiment of the present disclosure and a cross-sectional structure along a first direction;

[0022] Figure 2 The diagram schematically shows a partial structure diagram of an edge of a solar cell according to an embodiment of the present disclosure;

[0023] Figure 3 Schematically shows a distribution diagram of a test segment according to an embodiment of the present disclosure;

[0024] Figure 4 Schematically shows a distribution diagram of a test segment according to another embodiment of the present disclosure;

[0025] Figure 5The figure schematically shows a distribution diagram of a test section according to yet another embodiment of the present disclosure.

[0026] [Description of Reference Numerals]

[0027] 1-semiconductor substrate; 2-collector grid line; 21-first collector grid line; 22-second collector grid line; 3-test section; 31-contact platform; 32-recess structure; 33-first test section; 34-second test section; 4-terminal line; 5-first welding structure; 6-second welding structure; 7-auxiliary test electrode. DETAILED DESCRIPTION

[0028] In order to make the objectives, technical solutions and advantages of the present disclosure more clearly understood, the present disclosure is further described in detail below in combination with specific embodiments and with reference to the accompanying drawings.

[0029] It should be noted that in the drawings or descriptions, similar or identical parts use the same figure numbers. The technical features in the various embodiments exemplified in the specification can be freely combined to form a new solution without conflict. In addition, each claim can be used as an embodiment alone or the technical features in each claim can be combined as a new embodiment. In the drawings, the shape or thickness of the embodiment can be expanded and simplified or conveniently indicated. Furthermore, the elements or implementations not shown or described in the drawings are in a form known to a person of ordinary skill in the art. In addition, although demonstrations of parameters containing specific values ​​may be provided herein, it should be understood that the parameters do not need to be exactly equal to the corresponding values, but can be approximated to the corresponding values ​​within an acceptable error tolerance or design constraint.

[0030] Unless there are technical obstacles or contradictions, the above-mentioned various embodiments of the present disclosure can be freely combined to form additional embodiments, and these additional embodiments are all within the protection scope of the present disclosure.

[0031] Although the present disclosure is described in conjunction with the accompanying drawings, the embodiments disclosed in the drawings are intended to exemplify the embodiments of the present disclosure and should not be construed as limiting the present disclosure. The dimensional ratios in the drawings are merely illustrative and should not be construed as limiting the present disclosure.

[0032] Although some embodiments of the present general inventive concept have been shown and described, it will be appreciated by those skilled in the art that changes may be made to these embodiments without departing from the principles and spirit of the present general inventive concept, the scope of which is defined by the claims and their equivalents.

[0033] Figure 1A A partial plan view of the structure of a solar cell according to an embodiment of the present disclosure is schematically shown. Figure 1BA comparison diagram of a plane structure and a cross-sectional structure along a first direction of a test section according to an embodiment of the present disclosure is schematically shown.

[0034] According to the embodiments of the present disclosure, Figure 1A As shown in 1B, the present disclosure provides a solar cell, comprising: a semiconductor substrate 1. A plurality of collector grid lines 2 extending along a first direction x are arranged on the semiconductor substrate 1, and a plurality of protrusions are provided on the surface of the collector grid lines 2. The protrusions are spaced apart along the first direction x. At least one collector grid line 2 has at least one test section 3, and the surface of the collector grid line 2 in the test section 3 has a plurality of contact platforms 31 spaced apart along the first direction x, and the tops of at least some of the protrusions of the collector grid line 2 in the test section 3 form contact platforms 31.

[0035] In some embodiments, for example, single crystal silicon or polycrystalline silicon is used as the semiconductor substrate material.

[0036] On the semiconductor substrate, a plurality of collector grid lines are arranged extending along the first direction x. These collector grid lines are evenly spaced and distributed in the second direction y (eg, perpendicular to the first direction x), ensuring that the current is evenly distributed on the entire solar cell surface.

[0037] For example, the collector grid lines in this embodiment can be continuous collector grid lines along the first direction, or multiple discontinuous collector grid lines on the same straight line, and the spacing between adjacent discontinuous collector grid lines can be, for example, 40μm~6000μm. The collector grid lines on the same straight line have the same polarity, and the adjacent collector grid lines along the second direction have opposite polarities, and the spacing between adjacent opposite-sex collector grid lines is, for example, 0.2mm~2mm. The width of the collector grid line is, for example, 10μm~500μm.

[0038] The collector grid line material is, for example, silver or copper alloy with high conductivity to reduce resistance loss and improve photoelectric conversion efficiency.

[0039] At least one test section is formed on at least one collector grid line for connecting with a test probe to perform an electrical performance test on the solar cell.

[0040] For example, the test segment can be located on an independent collector grid line, or at the intersection of the collector grid line and the terminal line in the following embodiments, the intersection of the collector grid line and at least one of the auxiliary test electrode and the first welding structure, and the intersection of the collector grid line and the second welding structure.

[0041] Exemplarily, a test segment corresponds to a test probe or a section of a test probe strip, and a contact platform formed in a test segment corresponds to a raised portion of a collector grid line. The contact platform can be located on a continuously distributed raised portion or on a discontinuously distributed raised portion, depending mainly on whether the height of the raised portion is high enough.

[0042] In some embodiments, a plurality of contact platforms formed in the test section are located on top of a plurality of continuously distributed protrusions, and at most one contact platform is formed on the top of each protrusion.

[0043] For example, on at least one collector grid line, the number of protrusions in the test section is further increased, and their spacing along the first direction is reduced. This refined design makes the distribution of the protrusions on the collector grid line more dense, thereby increasing the contact area with the test probe. At the same time, a contact platform is formed on the top of each protrusion, and each protrusion forms at most one contact platform to avoid overcrowding and possible current interference.

[0044] As the number of protrusions in the test section increases and a contact platform is formed on the top of each protrusion, the number of contact platforms in the test section also increases accordingly. This design not only provides more test points, but also ensures stable current transmission during the test. Because each protrusion acts as an independent current collection point, the contact platform on its top can more accurately reflect the current situation at that point, thereby improving the accuracy and stability of the test.

[0045] It should be noted that, among the multiple collector grid lines electrically connected to the same terminal line, the test section may be provided on any one or more of the collector grid lines.

[0046] Exemplarily, the test section is located at a middle position of the intersection of the terminal line, the auxiliary test electrode, the first welding structure and the second welding structure.

[0047] Each test section is composed of a plurality of tiny contact platforms (ie, raised structures that are high enough to contact the probe), which are arranged at intervals along the extension direction of the collector grid line.

[0048] For example, the specific shape of the contact platform when viewed from above is one of various shapes such as an elliptical hemisphere, a circle, or a square. The top of the contact platform away from the semiconductor substrate can be flattened to form a flat contact platform, or processed to form a concave contact platform. In actual operation, the contact platform can be realized by processing the surface of the collector grid line through a mold to ensure good conductivity and stability when contacting with the probe. The material of the contact platform is the same as that of the collector grid line, ensuring the consistency of electrical performance.

[0049] It should be noted that the surface of the collector grid line itself is not an absolute plane, but has multiple protrusions. The contact platform in the present disclosure is obtained by further raising, making a specific shape, and flattening the top of some protrusions. Even if the surface of the contact platform is processed into a concave structure, the depth of the concave structure is much smaller than the height of the protrusion.

[0050] like Figure 1B As shown, a recessed structure 32 is formed between adjacent contact platforms 31, and a height h1 of the contact platform 31 is greater than a height h2 of the recessed structure 32. The interval between the contact platforms 31 (i.e., the minimum length of the recessed structure 32 along the first direction x) is optimized according to the size of the solar cell and the test requirements, which not only ensures the accuracy of the test, but also avoids mutual interference during the test process.

[0051] For example, the height h1 of the contact platform 31 may be in the range of 5 μm to 60 μm, and the height h2 of the recessed structure 32 may be in the range of 3 μm to 50 μm. The height difference h1-h2>1 μm. The difference needs to be larger to achieve close and stable contact between the test probe and the test section.

[0052] In some embodiments, the height of the contact platforms at two ends of the test section is greater than the height of the contact platforms at other than two ends of the test section.

[0053] During the test, the probes are more likely to wear out at both ends due to frequent contact and possible positioning adjustments. By increasing the height of the contact platform at both ends of the test section, the continuity and accuracy of the test can be ensured.

[0054] During the test, due to the increase in the height of the contact platform at both ends of the test section, the probe is in closer contact with these locations, reducing poor contact or test errors caused by wear. At the same time, this design also helps to improve test efficiency because it reduces the interruption time required for frequent probe replacement due to probe wear.

[0055] In the actual manufacturing process, the height of the contact platform can be differentiated by adjusting the processing depth of the top of the protrusion or using molds of different heights. Ensure that the contact platform at both ends of the test section is higher than the contact platform at the other ends by a certain preset value, which can be adjusted according to the wear rate of the probe and the test requirements.

[0056] For another example, in the first direction, the length of a single test segment is L, and the value range of L may be 50 μm to 5000 μm, so as to facilitate the test probe to be pressed onto the test segment.

[0057] In a single test section, the length L1 of a single contact platform can range from 1μm to 200μm, and the length L2 of a single recessed structure can range from 1μm to 200μm. The length L1 of a single contact platform accounts for 10% to 90% of L. Too many contact platforms will only provide limited help to the contact probe, but will reduce efficiency. If the proportion of the contact platform is too small, it is easy to cause excessive contact resistance.

[0058] For example, on a collector grid line, the total length of the test section is L total <50mm, exemplarily less than 20mm, and L total The proportion of the entire collector grid line t is less than 20%, and is exemplarily less than 10%. Since the top of the contact platform is relatively flat, secondary reflection of the incident light will cause partial light loss, so the proportion of the test section should not be too high.

[0059] If the collector grid is discontinuous, each discontinuous collector grid has at least one test section, and the length of the test section accounts for a ratio of t<20% of the length of the corresponding discontinuous collector grid.

[0060] When conducting electrical performance tests, the test probes are aligned with the contact platforms of each test section and the electrical parameters of the solar cell are measured by applying voltage or current.

[0061] Due to the presence of the contact platform, the test probe can stably contact the collector grid line, reducing the test error caused by poor contact. At the same time, the design of multiple contact platforms also provides redundancy. Even if a contact platform cannot be used due to wear or contamination, other contact platforms can still ensure the smooth progress of the test.

[0062] Through the above design, the solar cell can significantly improve the accuracy and reliability of the test during the test process, providing strong support for the research and development and production of solar cells.

[0063] According to an embodiment of the present disclosure, the contact platform 31 has a first surface away from the semiconductor substrate 1, and the solar cell further comprises: a doped semiconductor layer disposed between the semiconductor substrate 1 and the collector grid line 2. An alloy layer is formed between the collector grid line 2 and the doped semiconductor layer, and the distance between the first surface and the alloy layer is 10 μm to 40 μm.

[0064] In some embodiments, a layer of silicon nitride is deposited on the semiconductor substrate as an anti-reflection layer to improve the light absorption efficiency of the solar cell. A paste containing silver particles is coated on the silicon nitride anti-reflection layer by screen printing or other coating techniques.

[0065] During the high-temperature sintering process, the silver paste reacts chemically with the silicon nitride anti-reflection layer to form a dense silver-silicon alloy layer. This alloy layer not only strengthens the bonding force between the collector grid line and the semiconductor substrate, but also improves the conductivity.

[0066] In this embodiment, special attention is paid to the distance between the first surface of the contact platform (i.e., the side away from the semiconductor substrate) and the alloy layer. This distance is achieved by precisely controlling the height of the contact platform and the thickness of the alloy layer, for example, it can be 10μm, 15μm, 20μm, 25μm, 30μm, 35μm, 40μm, etc. The first surface can be platform-shaped or concave-shaped.

[0067] The height of the contact platform is designed to be slightly higher than the overall height of the collector grid line to ensure that during the test, the probe first contacts the top of the contact platform instead of pressing directly on the alloy layer, which can avoid unnecessary mechanical damage to the alloy layer.

[0068] At the same time, by adjusting the silver paste formula and sintering process parameters, the thickness of the alloy layer can be precisely controlled to ensure that the distance between it and the contact platform is neither too large to cause inaccurate testing nor too small to increase the probe contact resistance.

[0069] When conducting electrical performance tests, the test probe will contact the contact platform of each test section. Since the contact platform is kept at an appropriate distance from the alloy layer, the probe will not damage the alloy layer when applying voltage or current.

[0070] Through this design, the solar cell can avoid damage to the alloy layer during the test process, reduce the increase in probe contact resistance, and provide a more accurate and reliable testing method for the solar cell.

[0071] Figure 2 The diagram schematically shows a partial structure of an edge of a solar cell according to an embodiment of the present disclosure.

[0072] According to the embodiments of the present disclosure, Figure 2 As shown, the collector grid line 2 includes a first collector grid line 21 and a second collector grid line 22 with opposite polarities and alternately spaced along the second direction y, and the second direction y intersects with the first direction x. The solar cell also includes: a plurality of terminal wires 4 with opposite polarities, extending along the second direction y and spaced along the first direction x. And a first welding structure 5 arranged on the terminal wires 4. The first collector grid line 21 close to the edge of the solar cell along the first direction x is electrically connected to the first welding structure 5 through the terminal wires 4 of the same polarity, and is isolated at the terminal wires 4 of different polarities. At least one collector grid line 2 directly electrically connected to the terminal wire 4 has a test segment 3, or at least one collector grid line 2 directly electrically connected to the first welding structure 5 has a test segment 3.

[0073] In some embodiments, the solar cell includes a P region and an N region, wherein the P region and the N region are respectively provided with collector grid lines, namely a first collector grid line and a second collector grid line. The first collector grid line and the second collector grid line have opposite polarities and are responsible for collecting and conducting currents of different polarities.

[0074] The solar cell, for example, further includes a plurality of terminal wires with opposite polarities, extending along the second direction and spaced apart along the first direction. These terminal wires are designed to intersect with the collector grid wires of corresponding polarities near the edge of the solar cell to form electrical connection points to converge the current collected by the collector grid wires from the cell.

[0075] Parameters such as the material, width and thickness of the terminal wire are designed according to specific application requirements to ensure good conductivity and mechanical strength.

[0076] At one end of the terminal line away from the edge of the solar cell extending along the first direction, a first welding structure is arranged, and its width along the second direction is further increased to provide a larger welding area and stronger mechanical support.

[0077] In this embodiment, at least part of the collector grid lines do not directly pass through the terminal line and the first welding structure. This can be achieved by adjusting the layout of the collector grid lines and the welding process.

[0078] Specifically, the lifting height of the collector grid during welding can be reduced by precisely controlling the size and shape of the collector grid, as well as parameters such as temperature, pressure and time during welding, where the collector grid is electrically connected to these structures.

[0079] In addition, special welding materials or processes, such as low melting point alloys or laser welding, may be used at the location where the collector grid is electrically connected to the welding structure to further reduce the height of the collector grid.

[0080] The first collector grid line close to the edge of the solar cell along the first direction is electrically connected to the first welding structure through the terminal line of the same polarity, and is isolated at the terminal line of different polarity. The isolation may be to disconnect the first collector grid line at the terminal line position of opposite polarity, or to perform insulation treatment between the first collector grid line and the terminal line of different polarity, such as arranging an insulating material between the two for isolation.

[0081] At least one independent collector grid line, or at least one collector grid line directly electrically connected to the terminal line, or at least one collector grid line directly electrically connected to the first welding structure, or at least one collector grid line directly electrically connected to both the terminal line and the first welding structure can be provided with a test segment, and these test segments include a plurality of contact platforms spaced apart along the first direction. The collector grid lines at the edge positions are connected with the terminal line, so it is only necessary to ensure that at least one of the multiple collector grid lines connected to each other is provided with a test segment, so that the current in the corresponding area of ​​the collector grid line can be collected. That is, the number of collector grid lines with test segments can be less than or equal to the total number of collector grid lines.

[0082] Since the height of the collector grid wire at the welding structure and the terminal wire is controlled, the test section can more accurately reflect the actual performance of the solar cell.

[0083] Through the above optimization measures, the height increase of the collector grid line when penetrating the relevant structure is effectively controlled. This can not only reduce the contact resistance between the collector grid line and the semiconductor substrate or the adjacent collector grid line, but also avoid the risk of mechanical stress concentration and fracture of the collector grid line caused by the height increase.

[0084] It should be noted that Figure 2 This is the case where the collector grid line is connected. When it is not connected, the collector grid line only needs to be electrically connected to the corresponding structure. Although the connection of the collector grid line will cause the height of the PAD point to rise, in order to improve the accuracy of the test, the test fixture needs to be pressed onto the collector grid line. Therefore, it is still necessary to retain a part of the collector grid line that passes through the PAD point.

[0085] According to the embodiments of the present disclosure, Figure 2 As shown, the solar cell further includes: a second welding structure 6 disposed on the straight line where the end line 4 is located and not electrically connected to the end line 4, the second welding structure 6 is electrically connected to the collector grid line 2 of the same polarity away from the edge of the solar cell extending along the first direction x, and the width of the second welding structure 6 along the second direction y is less than the width of the first welding structure 5 along the second direction y. The distance between the test section 3 and at least one of the corresponding second welding structure 6, the first welding structure 5 and the end line 4 is less than or equal to 30 mm.

[0086] In some embodiments, a second welding structure (PAD point, used to connect the conductive interconnect) is added, which is arranged on the straight line where the terminal line is located and is electrically connected to the collector grid line, but not electrically connected to the terminal line. The second welding structure is designed to provide an additional electrical connection point and enhance the connection reliability between the collector grid line and the PAD point.

[0087] For example, the side length of the second welding structure ranges from 30 μm to 6000 μm, and the second welding structure may be a rectangle or a square, or an arc-cornered square, etc. In the case of a rectangle or a quasi-rectangle, the long side is exemplarily along the first direction.

[0088] A plurality of second welding structures may be provided on the same collector grid line along the first direction, and the distance between adjacent second welding structures is, for example, 5 mm to 40 mm.

[0089] For example, at least one collector grid line intersecting with the terminal line is provided with a test section, and each collector grid line not intersecting with the terminal line is provided with a test section.

[0090] In this embodiment, special attention is paid to the distance between the test section and at least one of the corresponding second welding structure, the first welding structure and the terminal line. This distance is designed to be less than a preset value of 30 mm, such as 25 mm, 20 mm, 15 mm, 10 mm, 5 mm, etc., to ensure that the test section can accurately reflect the performance of the solar cell under actual working conditions.

[0091] The preset value is determined based on the design parameters of the solar cell, the test requirements and the characteristics of the welding structure. Through measurement and calculation, a suitable preset value can be determined so that the distance between the test section and the welding structure is neither too large to cause inaccurate testing nor too small to increase the risk during the test.

[0092] For example, the distance between the test section and at least one of the corresponding second welding structure, the first welding structure and the terminal line is less than or equal to 30 mm, and illustratively, less than or equal to 10 mm.

[0093] Since the distance between the test section and the welding structure is strictly controlled, the test section can more accurately reflect the electrical performance and mechanical strength of the solar cell under actual working conditions.

[0094] In addition, due to the introduction of the second welding structure, the connection reliability between the collector grid line and the welding point is enhanced, thereby further improving the accuracy and reliability of the test.

[0095] According to the embodiments of the present disclosure, Figure 2As shown, the solar cell further includes: an auxiliary test electrode 7, which is arranged at the intersection of the terminal line 4 and at least one electrically connected collector grid line 2, and is electrically connected to the terminal line 4. The width of the auxiliary test electrode 7 along the second direction y is less than the width of the first welding structure 5 along the second direction y, and is greater than the width of the collector grid line 2, and the length of the auxiliary test electrode 7 along the first direction x is greater than the width of the terminal line 4. The number of contact platforms 31 in a single test segment 3 on the collector grid line 2 where the auxiliary test electrode 7 is arranged is greater than the number of contact platforms 31 in a single test segment 3 on the collector grid line 2 where the auxiliary test electrode 7 is not arranged.

[0096] In some embodiments, an auxiliary test electrode electrically connected to the terminal line is provided at the intersection of the terminal line and at least one intersecting collector grid line. The design of this welding structure is intended to enhance the reliability and stability of the electrical connection point.

[0097] The length of the auxiliary test electrode along the first direction is designed to be greater than the width of the terminal line to ensure that the welding area is large enough to withstand a large current density and mechanical stress. At the same time, the width of the auxiliary test electrode along the second direction is also designed to be greater than the width of the collector grid line to further increase the area and strength of the welding area.

[0098] For example, at least part of the collector grid lines may not directly penetrate the terminal line and the auxiliary test electrode. This can be achieved by adjusting the layout of the collector grid lines and the welding process.

[0099] For another example, the distance between the test segment and the corresponding auxiliary test electrode is less than or equal to 30 mm, and illustratively, less than or equal to 10 mm.

[0100] In the test section arranged on the collector grid line superimposed on the auxiliary test electrode, the number of contact platforms is designed to be greater than the number of contact platforms in the test section on the collector grid line not superimposed on the auxiliary test electrode.

[0101] This is because the collector grid line (thickened section) intersecting the terminal line may produce slight deformation or displacement due to factors such as thermal stress during the welding process, resulting in an increase in the contact resistance between it and the semiconductor substrate or the adjacent collector grid line. At the same time, the height of the collector grid line with a thickened section on the terminal line is also the highest. Therefore, increasing the number of contact platforms can provide more test points, thereby improving the accuracy and reliability of the test.

[0102] The specific number, shape and distribution of the contact platforms can be optimized according to the size of the solar cell, the test requirements and the characteristics of the welding structure.

[0103] When conducting an electrical performance test, the test probe will contact each contact platform of the test segment. Since the test segment on the collector grid line on the thickened segment has more contact platforms, it can provide more test data points, thereby more accurately evaluating the performance of the solar cell.

[0104] In addition, since the design of the auxiliary test electrodes enhances the reliability and stability of the electrical connection points, the accuracy and consistency of the test results can be ensured even if a large voltage or current is applied during the test.

[0105] Figure 3 The diagram schematically shows a distribution diagram of a test segment according to an embodiment of the present disclosure.

[0106] According to the embodiments of the present disclosure, Figure 3 As shown, each test section 3 is located on the same side of the straight line where the corresponding first welding structure 5 is located.

[0107] In some embodiments, each test segment is arranged on the same side of the line where the first welding structure is located. This means that all the test segments are located on the same side (eg, left or right) of the first welding structure, rather than being scattered on both sides.

[0108] This design of unidirectional offset helps to achieve uniform current collection. Since the test sections are all located on the same side, they can more effectively collect the current flowing from the collector grid line to the first welding structure, the terminal line and the second welding structure, reducing the uneven distribution of current inside the solar cell.

[0109] By setting the test sections to be offset in the same direction, it can be ensured that during the test, the current can pass through the collector grid line, the first welding structure, the terminal line and the second welding structure more evenly, reducing the risk of local overheating or current congestion.

[0110] Figure 4 The figure schematically shows a distribution diagram of a test section according to another embodiment of the present disclosure.

[0111] According to the embodiments of the present disclosure, Figure 4 As shown, with the line passing through the geometric center of the solar cell and extending along the second direction y as the central axis, the test segment 3 arranged on the first side of the central axis is offset along the first direction x relative to the straight line where the corresponding first welding structure 5 is located, and the test segment 3 arranged on the second side of the central axis is offset along the first direction x relative to the straight line where the corresponding first welding structure 5 is located, and the offset distances of the test segments 3 distributed on the first side and the second side of the same collector grid line 2 are equal and the offset directions are opposite, and the first side and the second side are opposite sides.

[0112] In some embodiments, the line passing through the geometric center of the solar cell and extending along the second direction is the central axis. The test segment disposed on the first side (e.g., the right side) of the central axis is offset by a certain distance in the first direction relative to the straight line where the corresponding first welding structure is located. The test segment disposed on the second side (i.e., the opposite first side, here the left side) of the central axis is offset by a certain distance in the opposite direction of the offset direction of the test segment on the first side relative to the straight line where the corresponding first welding structure is located.

[0113] The offset distances of the test segments offset in different directions on the same collector grid line are equal to ensure uniform collection of current.

[0114] With this symmetrically offset design, the test segments are more evenly distributed across the solar cell, helping to reduce the risk of local current congestion and overheating.

[0115] When the photo-generated current flows to the terminal line and the second welding structure through the collector grid line, the current can be more evenly distributed on the entire solar cell due to the symmetrical offset of the test section, thereby improving the uniformity of the collected current.

[0116] According to an embodiment of the present disclosure, the test segments 3 on the collector grid lines 2 electrically connected to the terminal lines 4 form a plurality of first test point sequences along the second direction y. The test segments 3 on the collector grid lines 2 not electrically connected to the terminal lines 4 form a plurality of second test point sequences along the second direction y. The number of the first test point sequences is different from the number of the second test point sequences, and the spacing between the first test point sequences is greater than the spacing between the second test point sequences.

[0117] In some embodiments, the test segments on the collector grid lines electrically connected to the terminal lines form a plurality of first test point sequences along the second direction. These test points are located on the edge collector grid lines, close to the edge of the solar cell.

[0118] The test segments on the collector grid lines that are not electrically connected to the terminal lines form a plurality of second test point sequences along the second direction. These test points are located on the non-edge collector grid lines, relatively far from the edge of the solar cell, that is, close to the center area of ​​the solar cell.

[0119] The number of the first test point sequence is different from the number of the second test point sequence. This depends on the design requirements and test requirements of the solar cell. For example, in order to understand the performance of the edge area in more detail or to enhance the contact of the probe in the edge area (which has a greater curvature during testing), more first test point sequences may be set.

[0120] Since the number of the first test point sequence and the second test point sequence is different, the spacing between each first test point sequence is greater than the spacing between each second test point sequence. That is, whether it is an edge collector grid line or a non-edge collector grid line, the spacing between the respective test points is consistent, that is, the spacing between the first sequences is equal, and the spacing between the second sequences is equal, so as to ensure the uniformity of the test.

[0121] This design allows for stable and uniform testing of different regions of the solar cell. The performance of the edge region can be evaluated using a first test point sequence, while the performance of the non-edge region can be evaluated using a second test point sequence.

[0122] This test point sequence design can be applied to various types of solar cells, including monocrystalline silicon, polycrystalline silicon and amorphous silicon solar cells. It not only improves the accuracy and reliability of the test, but also helps to better understand the performance of solar cells in different areas. By adjusting the number and spacing of the first test point sequence and the second test point sequence, it can flexibly adapt to different test requirements and solar cell designs.

[0123] Figure 5 The figure schematically shows a distribution diagram of a test section according to yet another embodiment of the present disclosure.

[0124] According to the embodiments of the present disclosure, Figure 5 As shown, each first collector grid line 21 is provided with a plurality of first test segments 33 spaced apart along the first direction x, and the plurality of first test segments 33 constitute a plurality of third test point sequences spaced apart along the second direction y. Each second collector grid line 22 is provided with a plurality of second test segments 34 spaced apart along the first direction x, and the plurality of second test segments 34 constitute a plurality of fourth test point sequences spaced apart along the second direction y. The third test point sequence is not collinear with the fourth test point sequence.

[0125] In some embodiments, each first collector grid line is provided with a plurality of first test segments spaced apart along the first direction, and these first test segments constitute a plurality of third test point sequences spaced apart along the second direction.

[0126] The spacing and number of the third test point sequence are optimally designed according to the current density and distribution characteristics of the P region to ensure that the current can be collected evenly.

[0127] A plurality of second test segments spaced apart along the first direction are respectively arranged on each second collector grid line, and these second test segments constitute a plurality of fourth test point sequences spaced apart along the second direction.

[0128] The spacing and number of the fourth test point sequence are optimized according to the current density and distribution characteristics of the N region, similar to the third test point sequence, and are intended to achieve uniform collection of the current in the N region.

[0129] The third test point sequence and the fourth test point sequence are not collinear, that is, they are located on the collector grid lines of the P region and the N region, respectively, avoiding interference and overlap between the test points. This design ensures that the currents of the P region and the N region can be collected independently and evenly, thereby improving the efficiency and performance of the solar cell.

[0130] Furthermore, the number of test segments on the first collector grid line and the second collector grid line is the same, which can ensure current matching between the P region and the N region, uniformly collect current and test the open voltage.

[0131] By optimizing the spacing and number of the third test point sequence and the fourth test point sequence, the current on the collector grid lines of the P region and the N region is evenly collected, avoiding the problem of excessive or insufficient local current. Uniform current collection helps reduce current loss and heat accumulation, thereby improving the conversion efficiency and stability of solar cells.

[0132] According to an embodiment of the present disclosure, the first test point sequence is collinear with the corresponding terminal line 4 , and the second test point sequence is not collinear with the first test point sequence.

[0133] In some embodiments, the first test point sequence is located on the edge collector grid line and is colinear with the corresponding terminal line, which means that the test section of the edge area is directly near the terminal line (or auxiliary test electrode, first welding structure) with a small degree of offset.

[0134] Since the edge area is close to the edge of the solar cell, the contact platform has a relatively small effect on the height increase of the test section, that is, the effect of the contact platform on the test stability is alleviated to a certain extent, so the offset of the test section can be relatively small.

[0135] The second test point sequence is located on the non-edge collector grid line and is not collinear with the first test point sequence (i.e. the test segment in the edge area). This means that the test segment in the middle area has a larger offset relative to the second welding structure (PAD point).

[0136] The greater degree of offset makes the contact platform of the test section in the middle area farther from the PAD point, thereby reducing the impact of the contact platform on the height increase of the test section. This helps to improve the accuracy of the test.

[0137] By adjusting the offset of the test segment relative to the PAD point, the test segment in the middle area can more effectively avoid the impact of the contact platform on the height lift, thereby improving the accuracy of the test. The test segments in the edge area and the middle area achieve differentiated treatment of the impact of the contact platform through different offset designs. This design not only improves the accuracy of the test, but also helps to improve the stability of the test.

[0138] Another aspect of the present disclosure provides a photovoltaic module, including: a plurality of solar cells connected by conductive interconnects, the conductive interconnects covering a portion of each solar cell along a second direction. An encapsulation layer, used to cover the surface of the plurality of solar cells. A cover plate, used to cover the surface of the encapsulation layer away from the plurality of solar cells. At least one test section is formed on the area of ​​at least one collector grid line not covered by the conductive interconnects, the collector grid line extends along a first direction, the test section includes a plurality of contact platforms spaced apart along the first direction, the contact platforms are used to contact with a probe to perform an electrical performance test on the photovoltaic module, and the second direction intersects with the first direction.

[0139] In some embodiments, the photovoltaic module mainly includes the following parts:

[0140] Multiple solar cells, which are the core part of photovoltaic modules, are responsible for converting light energy into electrical energy. They are arranged and connected together through a specific process to form a power output with a certain voltage and current.

[0141] The conductive interconnector is used to connect multiple solar cells to realize the series or parallel connection of current. In this example, the conductive interconnector not only plays a connecting role, but also forms at least one test segment at the connection with the solar cell and the collector grid line in the extension direction.

[0142] The encapsulation layer covers the surface of multiple solar cells and plays a protective and supporting role. It is usually made of transparent and highly viscous materials such as EVA (ethylene-vinyl acetate copolymer) and POE film, which can effectively prevent the external environment from corroding the solar cells.

[0143] The cover plate is located above the encapsulation layer and is used to further protect the photovoltaic module from the external environment. It is usually made of high-strength and high-transmittance materials such as tempered glass.

[0144] The test section is located between the connection between the conductive interconnect and the solar cell and the edge of the corresponding solar cell, or located on the collector grid line in the extension direction of the conductive interconnect. The test section includes a plurality of contact platforms spaced apart along a first direction (i.e., the extension direction of the collector grid line). These contact platforms can be hemispherical, cylindrical, or other shapes that are easy to contact with the probe.

[0145] The main function of the contact platform is to contact the test probes in order to test the electrical performance of photovoltaic modules. By measuring the voltage, current and other parameters between different test points, the key performance of photovoltaic modules such as power generation capacity, conversion efficiency and stability can be evaluated.

[0146] Designing the test section near the conductive interconnect not only saves additional test point space, but also makes the test process more convenient. At the same time, the design of the contact platform improves the contact stability between the test probe and the test section, thereby ensuring the accuracy of the test results.

[0147] It should be understood that the specific order or hierarchy of steps in the disclosed process is an example of an exemplary method. Based on design preferences, it should be understood that the specific order or hierarchy of steps in the process can be rearranged without departing from the scope of protection of the present disclosure. The attached method claims present the elements of the various steps in an exemplary order and are not intended to be limited to a specific order or hierarchy.

[0148] It should also be noted that the directional terms mentioned in the embodiments, such as "upper", "lower", "front", "back", "left", "right", etc., are only reference directions of the drawings and are not intended to limit the scope of protection of the present disclosure. Throughout the drawings, the same elements are represented by the same or similar reference numerals. Conventional structures or configurations will be omitted when they may cause confusion in the understanding of the present disclosure. In addition, the shapes, sizes, and positional relationships of the components in the drawings do not reflect the actual sizes, proportions, and actual positional relationships.

[0149] In the above detailed description, various features are grouped together in a single embodiment to simplify the disclosure. This method of disclosure should not be interpreted as reflecting an intention that the embodiments of the claimed subject matter require more features than are clearly stated in each claim. On the contrary, as reflected in the attached claims, the disclosure is in a state of having less than all the features of a single disclosed embodiment. Therefore, the attached claims are hereby expressly incorporated into the detailed description, with each claim standing on its own as a separate embodiment of the disclosure.

[0150] In addition, the terms "first" and "second" are used for descriptive purposes only and are not to be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present disclosure, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined. With respect to the term "comprising" used in the specification or claims, the word is covered in a manner similar to the term "including", as explained in terms of "including," used as a transitional word in the claims. Any term "or" used in the specification of the claims is intended to mean "non-exclusive or".

[0151] The specific embodiments described above further illustrate the purpose, technical solutions and beneficial effects of the present disclosure. It should be understood that the above description is only a specific embodiment of the present disclosure and is not intended to limit the present disclosure. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present disclosure should be included in the protection scope of the present disclosure.

Claims

1. A solar cell, characterized in that: include: Semiconductor substrate; A plurality of collector gate lines extending along a first direction are arranged on the semiconductor substrate, and a plurality of protrusions are provided on the surface of the collector gate lines; the protrusions are distributed at intervals along the first direction; Among them, at least one of the collector grid lines has at least one test segment, the surface of the collector grid line in the test segment has a plurality of contact platforms spaced apart along the first direction, and the top of at least part of the raised portion of the collector grid line in the test segment forms the contact platform.

2. The solar cell according to claim 1, characterized in that: The contact platform has a first surface away from the semiconductor substrate, and the solar cell further comprises: A doped semiconductor layer is disposed between the semiconductor substrate and the collector grid line; Wherein, an alloy layer is formed between the collector grid line and the doped semiconductor layer, and the distance between the first surface and the alloy layer is 10 μm to 40 μm.

3. The solar cell according to claim 1, characterized in that The collector grid lines include first collector grid lines and second collector grid lines having opposite polarities and alternately spaced along a second direction, wherein the second direction intersects the first direction; The solar cell further comprises: a plurality of terminal lines having opposite polarities, extending along the second direction and spaced apart along the first direction; and a first welding structure disposed on the end line; the first collector grid line close to the edge of the solar cell along the first direction is electrically connected to the first welding structure through the end line of the same polarity and is isolated at the end line of different polarity; At least one collector grid line directly electrically connected to the terminal line has the test section, or at least one collector grid line directly electrically connected to the first welding structure has the test section.

4. The solar cell according to claim 3, characterized in that: Also includes: A second welding structure disposed on the straight line where the end line is located and not electrically connected to the end line, the second welding structure being electrically connected to the collector grid line of the same polarity away from the edge of the solar cell extending along the first direction, the width of the second welding structure along the second direction being smaller than the width of the first welding structure along the second direction; Wherein, the distance between the test section and the corresponding at least one of the second welding structure, the first welding structure and the terminal line is less than or equal to 30 mm.

5. The solar cell according to claim 3, characterized in that: Also includes: An auxiliary test electrode is disposed at the intersection of the terminal line and at least one electrically connected collector grid line, and is electrically connected to the terminal line; The width of the auxiliary test electrode along the second direction is smaller than the width of the first welding structure along the second direction and larger than the width of the collector grid line, and the length of the auxiliary test electrode along the first direction is larger than the width of the terminal line; The number of contact platforms in a single test section on the collector grid line where the auxiliary test electrode is provided is greater than the number of contact platforms in a single test section on the collector grid line where the auxiliary test electrode is not provided.

6. The solar cell according to claim 3, characterized in that: Each of the test sections is located on the same side of the straight line where the corresponding first welding structure is located.

7. The solar cell according to claim 3, characterized in that: Taking the line passing through the geometric center of the solar cell and extending along the second direction as the central axis, the test segment arranged on the first side of the central axis is offset along the first direction relative to the corresponding straight line where the first welding structure is located, and the test segment arranged on the second side of the central axis is offset along the first direction relative to the corresponding straight line where the first welding structure is located, and the offset distances of the test segments distributed on the first side and the second side of the same collector grid are equal and the offset directions are opposite, and the first side and the second side are opposite sides.

8. The solar cell according to claim 3, characterized in that: The test segments on the collector grid line electrically connected to the terminal line form a plurality of first test point sequences along the second direction; The test segments on the collector grid lines that are not electrically connected to the terminal lines form a plurality of second test point sequences along the second direction; The number of the first test point sequences is different from the number of the second test point sequences, and the spacing between the first test point sequences is greater than the spacing between the second test point sequences.

9. The solar cell according to claim 3, characterized in that: A plurality of first test segments spaced apart along the first direction are respectively arranged on each of the first collector grid lines, and the plurality of first test segments constitute a plurality of third test point sequences spaced apart along the second direction; A plurality of second test segments spaced apart along the first direction are respectively arranged on each of the second collector grid lines, and the plurality of second test segments constitute a plurality of fourth test point sequences spaced apart along the second direction; The third test point sequence and the fourth test point sequence are not collinear.

10. The solar cell according to claim 8, characterized in that The first test point sequence is collinear with the corresponding terminal line, and the second test point sequence is not collinear with the first test point sequence.

11. The solar cell according to claim 1, characterized in that: The multiple contact platforms formed in the test section are located on top of the multiple continuously distributed protrusions, and the top of each protrusion forms at most one contact platform.

12. The solar cell according to claim 1, characterized in that The height of the contact platforms located at two ends of the test section is greater than the height of the contact platforms located at other than two ends of the test section.

13. A photovoltaic module, characterized in that: include: A plurality of solar cells connected by a conductive interconnector, wherein the conductive interconnector covers a partial area of ​​each of the solar cells along a second direction; An encapsulation layer, used to cover the surface of the plurality of solar cells; A cover plate, used for covering a surface of the encapsulation layer away from the plurality of solar cells; At least one test segment is formed on an area of ​​at least one collector grid line not covered by the conductive interconnect, the collector grid line extends along a first direction, the test segment includes a plurality of contact platforms spaced apart along the first direction, the contact platforms are used to contact with a probe to perform an electrical performance test on the photovoltaic module, and the second direction intersects with the first direction.

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