Solder strip and photovoltaic module

Abstract

The application relates to the photovoltaic field, and provides a welding strip and a photovoltaic module. The welding strip is provided with light-reflecting protrusions on at least one side surface in the height direction of the welding strip, and the light-reflecting protrusions are arranged in an array. In the width direction of the welding strip, the heights of the light-reflecting protrusions gradually increase in the direction from the center of the welding strip to the two ends of the welding strip. The array formed by the light-reflecting protrusions has a structure that is low in the middle and gradually increases towards the two sides in the width direction of the welding strip. The structure can improve the reflection path of incident light on the surface of the welding strip, and can also cause the incident light to be scattered to a certain extent, so that the utilization rate of the incident light by the photovoltaic cell is improved, and the photoelectric conversion efficiency of the photovoltaic cell is improved.

Description

Technical Field

[0001] This application relates to the photovoltaic field, specifically to a welding strip and a photovoltaic module. Background Technology

[0002] Solar energy is an inexhaustible and renewable energy source for humankind. Photovoltaic modules are the core and most important component of a solar power generation system. Their function is to convert solar energy into electrical energy, which is then stored in batteries or used to power loads. A photovoltaic module consists of a battery array, which is composed of multiple battery strings connected in series or parallel. Each battery string includes multiple spaced photovoltaic cells, with adjacent cells connected by solder strips.

[0003] In existing technologies, solder ribbons can obstruct the solar cells, affecting their photoelectric conversion efficiency. To increase this efficiency, reflective structures are typically added to the solder ribbon surface to reflect unusable incident light onto the surface glass or surrounding solar cells. However, existing reflective structures are uniform, meaning some incident light still cannot be reflected onto the solar cells, thus limiting the improvement in photoelectric conversion efficiency. Summary of the Invention

[0004] In view of this, this application provides a solder strip and a photovoltaic module to help solve the problem of low photoelectric conversion efficiency of solar cells in the prior art.

[0005] In a first aspect, embodiments of this application provide a solder strip, wherein at least one surface of the solder strip along its height direction is provided with reflective protrusions, and a plurality of the reflective protrusions are arranged in an array; in the width direction of the solder strip, along the direction from the center of the solder strip to its two ends, the height of the plurality of reflective protrusions increases sequentially.

[0006] In one possible implementation, the gap between two adjacent reflective protrusions is less than 60 μm along the width direction of the solder strip; and / or, the gap between two adjacent reflective protrusions is less than 100 μm along the length direction of the solder strip.

[0007] In one possible implementation, the height of the reflective protrusion is 30μm-100μm along the height direction of the solder strip.

[0008] In one possible implementation, when an odd number of the reflective protrusions are arranged along the width direction of the solder strip in the array of reflective protrusions, the geometric center of the bottom surface of the central reflective protrusion is located on the center line of the width direction of the solder strip; when an even number of the reflective protrusions are arranged along the width direction of the solder strip in the array of reflective protrusions, the distances from the geometric centers of the bottom surfaces of the two central reflective protrusions to the center line of the width direction of the solder strip are equal.

[0009] In one possible implementation, the reflective protrusions include a first reflective protrusion, a second reflective protrusion, and a third reflective protrusion, which are arranged sequentially along the width direction of the solder strip, pointing from the center of the solder strip to both ends thereto; along the height direction of the solder strip, the height H1 of the first reflective protrusion is 10μm-50μm, the height H2 of the second reflective protrusion is 15μm-70μm, and the height H3 of the third reflective protrusion is 20μm-100μm, and H1 < H2 < H3; and / or, along the width direction of the solder strip, the width W1 of the first reflective protrusion is 50μm-300μm, the width W2 of the second reflective protrusion is 20μm-200μm, and the width W3 of the third reflective protrusion is 5μm-100μm.

[0010] In one possible implementation, the solder strip includes a substrate and a reflective film, the reflective film covering the surface of the substrate; along the height direction of the solder strip, the reflective protrusions are disposed on the surface of the reflective film away from the substrate.

[0011] In one possible implementation, the solder strip includes a substrate, and the reflective protrusions are disposed on one side surface of the substrate along its height direction.

[0012] In one possible implementation, at least one of the reflective protrusions is a reflective pyramid having at least three reflective bevels, each of which forms an unequal angle with the surface of the solder strip.

[0013] In one possible implementation, the angle between any of the reflective bevels and the surface of the solder strip is 20°-80°.

[0014] In one possible implementation, the reflective pyramid is one of a triangular pyramid, a square pyramid, a pentagonal pyramid, or a hexagonal pyramid.

[0015] Secondly, embodiments of this application provide a photovoltaic module, including: a battery string, comprising the aforementioned solder ribbon and a plurality of photovoltaic cells, wherein two adjacent photovoltaic cells are connected by the solder ribbon; an encapsulation layer for covering the surface of the battery string; and a cover plate for covering the surface of the encapsulation layer away from the battery string; wherein, along the thickness direction of the photovoltaic module, the surface of the solder ribbon with the reflective protrusion is positioned toward the cover plate.

[0016] In one possible implementation, the photovoltaic cell has an edge region and a main body region. The edge region is provided on both sides of the main body region along the width direction of the photovoltaic cell. The ratio of the width L1 of the edge region to the width L2 of the photovoltaic cell along the width direction of the photovoltaic cell satisfies 0.1≤L1:L2≤0.3. The height of any reflective protrusion on the solder strip located in the edge region is greater than the height of any reflective protrusion on the solder strip located in the main body region.

[0017] The beneficial effects of this application are as follows: The array of reflective protrusions has a structure that is lower in the middle and gradually increases towards both sides in the width direction of the solder strip. This improves the reflection path of incident light on the surface of the solder strip, prevents the reflective protrusions in the middle from blocking the light reflected by the reflective protrusions on both sides, improves the reflection efficiency of the reflective protrusions on both sides, and ensures that more light is utilized by the photovoltaic cells. Moreover, the array composed of multiple reflective protrusions with uneven heights can cause a certain degree of scattering of incident light, which can increase the propagation path of incident light inside the photovoltaic module and improve the uniformity of incident light, thereby improving the utilization rate of incident light by the photovoltaic cells. In addition, the array structure composed of reflective protrusions with uneven heights can alleviate the stress during welding and reduce the risk of microcracks in the photovoltaic cells during the welding process with the solder strip, thereby improving the mechanical reliability and service life of the photovoltaic cells.

[0018] It should be understood that the above general description and the following detailed description are merely exemplary and do not limit this application. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 A schematic cross-sectional view of the solder strip provided in this application in the first embodiment;

[0021] Figure 2 for Figure 1 Optical path diagram of the reflected light from the solder ribbon in the process;

[0022] Figure 3 A schematic cross-sectional view of the solder strip provided in this application in a second embodiment;

[0023] Figure 4 for Figure 1 The optical path diagram of the solder strip reflecting light in another embodiment;

[0024] Figure 5 A schematic cross-sectional view of the solder strip provided in this application in a third embodiment;

[0025] Figure 6 A schematic diagram of the structure of the solder strip provided in this application in the fourth embodiment;

[0026] Figure 7 A schematic diagram of the structure of the solder strip provided in this application in the fifth embodiment;

[0027] Figure 8 A schematic diagram of the structure of the solder strip provided in this application in the sixth embodiment;

[0028] Figure 9 A schematic diagram of the structure of the solder strip provided in this application in the seventh embodiment;

[0029] Figure 10 A schematic diagram of the photovoltaic module provided in this application in the first embodiment;

[0030] Figure 11 A schematic diagram of the photovoltaic module provided in this application in a second embodiment;

[0031] Figure 12 This is a schematic diagram of the structure of the solder ribbon and photovoltaic cells in the photovoltaic module provided in this application.

[0032] Figure label:

[0033] 10-Welding strip;

[0034] 20 - Photovoltaic cells;

[0035] 201 - Main Area;

[0036] 202 - Edge region;

[0037] 30 - Encapsulation layer;

[0038] 40 - Cover plate;

[0039] 401 - Top cover plate;

[0040] 402 - Lower cover plate;

[0041] 1-Reflective protrusions;

[0042] 11-First reflective protrusion;

[0043] 12-Second reflective protrusion;

[0044] 13-Third reflective protrusion;

[0045] 2-Matrix;

[0046] 3-Reflective film;

[0047] a1 - First incident ray;

[0048] a2 - Second incident ray;

[0049] b1 - First reflected ray;

[0050] b2 - Second reflected ray;

[0051] c1 - Secondary reflected ray.

[0052] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. Detailed Implementation

[0053] To better understand the technical solution of this application, the embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0054] It should be understood that the described embodiments are merely some, not all, of the embodiments in this application. All other embodiments obtained by those skilled in the art based on the embodiments in this application without inventive effort are within the scope of protection of this application.

[0055] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. The singular forms “a,” “the,” and “the” used in the embodiments of this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0056] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0057] It should be noted that the directional terms such as "upper," "lower," "left," and "right" described in the embodiments of this application are used to describe the angles shown in the accompanying drawings and should not be construed as limiting the embodiments of this application. Furthermore, in the context, it should be understood that when it is mentioned that an element is connected "upper" or "lower" to another element, it can be directly connected to the other element "upper" or "lower," or indirectly connected to the other element "upper" or "lower" through an intermediate element.

[0058] This application provides a solder strip 10, which can be applied in photovoltaic modules to achieve electrical connection between adjacent photovoltaic cells 20. For example... Figure 1 and Figure 2 As shown, reflective protrusions 1 are provided on at least one side surface of the solder ribbon 10 along its height direction Z, and multiple reflective protrusions 1 are arranged in an array on the surface of the solder ribbon 10. The reflective protrusions 1 can reflect the light illuminating the surface of the solder ribbon 10 onto the photovoltaic cell 20, or reflect it onto the cover plate 40 and then reflect it a second time onto the photovoltaic cell 20, which can increase the utilization rate of the photovoltaic cell 20 for incident light, thereby improving the photoelectric conversion efficiency of the photovoltaic cell 20 and thus improving the output power of the photovoltaic module.

[0059] The working principle of the reflective protrusion 1 is explained below using the example of the solder ribbon 10 being connected to the light-facing surface of the photovoltaic cell 20. Figure 2 As shown, when the solder ribbon 10 is connected to the light-facing surface of the photovoltaic cell 20, the reflective protrusion 1 is placed facing the cover plate 40 of the photovoltaic module. At this time, no matter which direction the light enters the surface of the solder ribbon 10 through the cover plate 40, it can be reflected onto the surface of the photovoltaic cell 20 under the action of the reflective protrusion 1.

[0060] Specifically, along the width direction X of the solder ribbon 10, from the center of the solder ribbon 10 towards both ends, the height of the multiple reflective protrusions 1 increases sequentially. That is, the array of reflective protrusions 1 has a structure that is shorter in the middle and gradually increases in height towards both sides along the width direction X of the solder ribbon 10. This improves the reflection path of incident light on the surface of the solder ribbon 10, preventing the reflective protrusion 1 in the middle from blocking the light reflected by the reflective protrusions 1 on both sides, thus increasing the reflection efficiency of the reflective protrusions 1 on both sides and ensuring that more light is utilized by the photovoltaic cell 20. Furthermore, the array composed of multiple reflective protrusions 1 with uneven heights can cause a certain degree of scattering of the incident light, increasing the propagation path of the incident light inside the photovoltaic module, improving the uniformity of the incident light, and thus helping to improve the utilization rate of the incident light by the photovoltaic cell 20. In addition, the array structure composed of highly uneven reflective protrusions 1 can alleviate the stress during welding and reduce the risk of microcracks in the photovoltaic cell 20 during the welding process with the welding strip 10, thereby improving the mechanical reliability and service life of the photovoltaic cell 20.

[0061] In this application embodiment, the specific number of reflective protrusions 1 is not limited, and can be designed according to actual usage requirements.

[0062] In some embodiments, in the array of reflective protrusions 1, an odd number or an even number of reflective protrusions 1 can be provided along the width direction X of the solder ribbon 10. When an odd number of reflective protrusions 1 are provided along the width direction X of the solder ribbon 10, the geometric center of the bottom surface of the central reflective protrusion 1 is located on the center line of the width direction X of the solder ribbon 10. This ensures that the array structure composed of reflective protrusions 1 can be uniformly distributed on the surface of the solder ribbon 10, which is beneficial to improving the uniformity of reflected light and also ensures that the stress on the solder ribbon 10 is uniform during the lamination process. When an even number of reflective protrusions 1 are provided along the width direction X of the solder ribbon 10, the distance from the geometric center of the bottom surface of the two central reflective protrusions 1 to the center line of the width direction X of the solder ribbon 10 is equal. This also ensures that the array structure composed of reflective protrusions 1 can be uniformly distributed on the surface of the solder ribbon 10, which is beneficial to improving the uniformity of reflected light and also ensures that the stress on the solder ribbon 10 is uniform during the lamination process.

[0063] In some embodiments, two adjacent reflective protrusions 1 can be continuously arranged along the width direction X of the solder ribbon 10. Alternatively, the gap between two adjacent reflective protrusions 1 can be less than 60 μm along the width direction X of the solder ribbon 10. That is, two adjacent reflective protrusions 1 can be arranged with a spacing of 60 μm or less, which can increase the number of reflective protrusions 1 in the width direction X of the solder ribbon 10, increase the effective reflective area of ​​the surface of the solder ribbon 10, and reduce the probability that incident light is absorbed by the platform area of ​​the surface of the solder ribbon 10 where no reflective protrusions 1 are provided, thereby improving the utilization rate of incident light by the photovoltaic cell 20.

[0064] Optionally, along the width direction X of the solder strip 10, the gap between two adjacent reflective protrusions 1 is 0.1μm-20μm, specifically 0.1μm, 1μm, 2μm, 3μm, 4μm, 5μm, 6μm, 7μm, 8μm, 9μm, 10μm, 11μm, 12μm, 13μm, 14μm, 15μm, 16μm, 17μm, 18μm, 19μm or 20μm, or other values ​​within the above range. This embodiment does not limit this.

[0065] Optionally, along the width direction X of the solder strip 10, the gap between two adjacent reflective protrusions 1 is 20μm-40μm, specifically 20μm, 21μm, 22μm, 23μm, 24μm, 25μm, 26μm, 27μm, 28μm, 29μm, 30μm, 31μm, 32μm, 33μm, 34μm, 35μm, 36μm, 37μm, 38μm, 39μm or 40μm, or other values ​​within the above range. This embodiment does not limit this.

[0066] Optionally, along the width direction X of the solder strip 10, the gap between two adjacent reflective protrusions 1 is 40μm-60μm, specifically 40μm, 41μm, 42μm, 43μm, 44μm, 45μm, 46μm, 47μm, 48μm, 49μm, 50μm, 51μm, 52μm, 53μm, 54μm, 55μm, 56μm, 57μm, 58μm, 59μm or 60μm, or other values ​​within the above range. This embodiment does not limit this.

[0067] In some embodiments, two adjacent reflective protrusions 1 can be continuously arranged along the length Y of the solder ribbon 10. Alternatively, the gap between two adjacent reflective protrusions 1 can be less than 100 μm along the length Y of the solder ribbon 10. That is, two adjacent reflective protrusions 1 can be arranged with a spacing of 100 μm or less, which can increase the number of reflective protrusions 1 along the length Y of the solder ribbon 10, increase the effective reflective area of ​​the surface of the solder ribbon 10, and reduce the probability that incident light is absorbed by the platform area of ​​the surface of the solder ribbon 10 where no reflective protrusions 1 are provided, thereby improving the utilization rate of incident light by the photovoltaic cell 20.

[0068] Optionally, along the width direction X of the solder strip 10, the gap between two adjacent reflective protrusions 1 is 0.1μm-30μm, specifically 0.1μm, 2μm, 4μm, 5μm, 6μm, 8μm, 10μm, 12μm, 14μm, 16μm, 18μm, 20μm, 22μm, 24μm, 26μm, 28μm or 30μm, or other values ​​within the above range. This embodiment does not limit this.

[0069] Optionally, along the width direction X of the solder strip 10, the gap between two adjacent reflective protrusions 1 is 30μm-60μm, specifically 30μm, 32μm, 34μm, 35μm, 36μm, 38μm, 40μm, 42μm, 44μm, 46μm, 48μm, 50μm, 52μm, 54μm, 56μm, 58μm or 60μm, or other values ​​within the above range. This embodiment does not limit this.

[0070] Optionally, along the width direction X of the solder strip 10, the gap between two adjacent reflective protrusions 1 is 60μm-100μm, specifically 60μm, 62μm, 64μm, 65μm, 66μm, 68μm, 70μm, 72μm, 74μm, 76μm, 78μm, 80μm, 82μm, 84μm, 86μm, 88μm, 90μm, 92μm, 94μm, 96μm, 98μm or 100μm, or other values ​​within the above range. This embodiment does not limit this.

[0071] In some embodiments, the height of the reflective protrusion 1 along the height direction Z of the solder ribbon 10 is 30μm-100μm. When the height of the reflective protrusion 1 meets this range, it can ensure that the height of the reflective protrusion 1 is high enough to increase the effective reflective area of ​​the surface of the solder ribbon 10, and it can also avoid the reflective protrusion 1 being too high, which would result in an excessively large projected area of ​​the reflective protrusion 1 on the photovoltaic cell 20. This reduces unnecessary shading caused by the solder ribbon 10 on the photovoltaic cell 20, thereby improving the utilization rate of the photovoltaic cell 20 for incident light.

[0072] Optionally, along the height direction Z of the solder strip 10, the height of the reflective protrusion 1 is 30μm-50μm, specifically 30μm, 32μm, 34μm, 36μm, 38μm, 40μm, 42μm, 44μm, 46μm, 48μm or 50μm, or other values ​​within the above range. This embodiment does not limit this.

[0073] Optionally, along the height direction Z of the solder strip 10, the height of the reflective protrusion 1 is 50μm-80μm, specifically 50μm, 52μm, 54μm, 56μm, 58μm, 60μm, 62μm, 64μm, 66μm, 68μm, 70μm, 72μm, 74μm, 76μm, 78μm or 80μm, or other values ​​within the above range. This embodiment does not limit this.

[0074] Optionally, along the height direction Z of the solder strip 10, the height of the reflective protrusion 1 is 80μm-100μm, specifically 80μm, 82μm, 84μm, 86μm, 88μm, 90μm, 92μm, 94μm, 96μm, 98μm, or 100μm, or other values ​​within the above range. This embodiment does not limit this.

[0075] In some embodiments, the reflective protrusion 1 can specifically be a reflective pyramid. The inclined structure of the reflective pyramid helps to increase the reflectivity of incident light, thereby ensuring that more incident light can be reflected onto the surface of the photovoltaic cell 20 under the action of the reflective protrusion 1. Optionally, as Figure 3 As shown, in the width direction X of the solder strip 10, along the direction from the center of the solder strip 10 to its two ends, the angle between the multiple reflective protrusions 1 and the surface of the solder strip 10 gradually increases, that is, the inclination of the slope of the reflective protrusion 1 gradually increases. This ensures that the reflective protrusion 1 in the middle reflects the incident light onto the unshaded areas of the photovoltaic cells 20 on both sides of the solder strip 10, thereby helping to further improve the utilization rate of the photovoltaic cells 20 for the incident light.

[0076] For example, in one specific embodiment, the solder strip 10 has five reflective protrusions 1 in the width direction X, and in the width direction X of the solder strip 10, the angle between the five reflective protrusions 1 and the surface of the solder strip 10 gradually increases along the direction from the center of the solder strip 10 to its two ends. Figure 3As shown, the five reflective protrusions 1 are divided into a first reflective protrusion 11, a second reflective protrusion 12, and a third reflective protrusion 13. The first reflective protrusion 11, the second reflective protrusion 12, and the third reflective protrusion 13 are arranged sequentially along the width direction X of the solder strip 10, pointing from the center of the solder strip 10 to both ends. That is, the second reflective protrusion 12 is provided on both sides of the first reflective protrusion 11, and the third reflective protrusion 13 is provided on the side of each of the two second reflective protrusions 12 away from the first reflective protrusion 11. Along the height direction Z of the solder strip 10, the height H1 of the first reflective protrusion 11 is 10μm-50μm, the height H2 of the second reflective protrusion 12 is 15μm-70μm, and the height H3 of the third reflective protrusion 13 is 20μm-100μm, and H1 < H2 < H3, so as to ensure that the array of reflective protrusions 1 has a structure that is short in the middle and gradually increases towards both sides in the width direction X of the solder strip 10. Along the width direction X of the solder strip 10, the width W1 of the first reflective protrusion 11 is 50μm-300μm, the width W2 of the second reflective protrusion 12 is 20μm-200μm, and the width W3 of the third reflective protrusion 13 is 5μm-100μm, so as to form a structure in which the slope of the first reflective protrusion 11, the second reflective protrusion 12, and the second reflective protrusion 13 gradually increases, ensuring that the reflective protrusion 1 in the middle reflects the incident light onto the unshaded areas of the photovoltaic cells 20 on both sides of the solder strip 10.

[0077] Optionally, H1 can be 10μm, 15μm, 20μm, 25μm, 30μm, 35μm, 40μm, 45μm or 50μm, or other values ​​within the above range. This embodiment does not limit this value.

[0078] Optionally, H2 can be 15μm, 20μm, 25μm, 30μm, 35μm, 40μm, 45μm, 50μm, 55μm, 60μm, 65μm or 70μm, or other values ​​within the above range. This embodiment does not limit this value.

[0079] Optionally, H3 can be 2020μm, 25μm, 30μm, 35μm, 40μm, 45μm, 50μm, 55μm, 60μm, 65μm, 70μm, 75μm, 80μm, 85μm, 90μm, 95μm or 100μm, or other values ​​within the above range. This embodiment does not limit this value.

[0080] Optionally, W1 can be 50μm, 60μm, 70μm, 80μm, 90μm, 100μm, 110μm, 120μm, 130μm, 140μm, 150μm, 160μm, 170μm, 180μm, 190μm, 200μm, 210μm, 220μm, 230μm, 240μm, 250μm, 260μm, 270μm, 280μm, 290μm, or 300μm, or other values ​​within the above range. This embodiment does not limit this value.

[0081] Optionally, W2 can be 20μm, 30μm, 40μm, 50μm, 60μm, 70μm, 80μm, 90μm, 100μm, 110μm, 120μm, 130μm, 140μm, 150μm, 160μm, 170μm, 180μm, 190μm or 200μm, or other values ​​within the above range. This embodiment does not limit this value.

[0082] Optionally, W3 can be 5μm, 10μm, 15μm, 20μm, 25μm, 30μm, 35μm, 40μm, 45μm, 50μm, 55μm, 60μm, 65μm, 70μm, 75μm, 80μm, 85μm, 90μm, 95μm or 100μm, or other values ​​within the above range. This embodiment does not limit this value.

[0083] In this embodiment, the plurality of first reflective protrusions 1 are symmetrically distributed in the width direction X of the solder strip 10. That is, the two second reflective protrusions 12 located on both sides of the first reflective protrusion 11 have the same structure and the same height, and the two third reflective protrusions 13 have the same structure and the same height. In some other embodiments, the plurality of first reflective protrusions 11 may also be asymmetrically distributed in the width direction X of the solder strip 10. That is, the structure of the reflective protrusions 1 located on both sides of the first reflective protrusion 11 may be asymmetrical, and / or the height of the reflective protrusions 1 located on both sides of the first reflective protrusion 11 may be asymmetrical. This application does not limit this. As long as the height of the plurality of reflective protrusions 1 satisfies the requirement that the height of the plurality of reflective protrusions 1 increases sequentially in the width direction X of the solder strip 10 from the center of the solder strip 10 to its two ends.

[0084] In some embodiments, at least one reflective protrusion 1 on the surface of the solder ribbon 10 is a reflective pyramid. That is, all of the multiple reflective protrusions 1 on the surface of the solder ribbon 10 can be reflective pyramids, or they can be a combination of reflective pyramids and other reflective structures. The reflective pyramid can be a regular pyramid or an asymmetrical pyramid. When the reflective pyramid is an asymmetrical pyramid, it has at least three reflective slopes, and the angles formed between each reflective slope and the surface of the solder ribbon 10 are not equal. The symmetrical pyramid structure can provide multiple independent slopes with different inclinations. Multiple slopes with different inclinations can match the changes in the azimuth angle and solar altitude angle of the sun at more times, thereby improving the refraction efficiency of the reflective protrusion 1 for the incident sunlight throughout the day's illumination, which in turn helps to improve the utilization rate of light by the photovoltaic cell 20.

[0085] Specifically, the angle formed between any reflective bevel and the surface of the solder ribbon 10 is between 20° and 80°. When the angle between the reflective bevel and the surface of the solder ribbon 10 meets the above range, the angle will not be too large, thus preventing the reflective protrusion 1 from failing to reflect the incident light onto the surface of the photovoltaic cell 20. Moreover, the angle will not be too large, thus preventing the reflective protrusion 1 from directly reflecting the incident light back to the cover plate 40, thereby reducing the risk that the light reflected back to the cover plate 40 will directly exit the photovoltaic module through the cover plate 40. Therefore, when the angle formed between any reflective bevel and the surface of the solder ribbon 10 is between 20° and 80°, the reflective bevel can reflect the incident light at the optimal angle onto the unblocked area of ​​the photovoltaic cell 20, reducing light loss and thus improving the utilization rate of the incident light by the photovoltaic cell 20.

[0086] Optionally, the angle formed between any reflective bevel and the surface of the solder strip 10 is 20°-50°, specifically 20°, 22°, 24°, 25°, 26°, 28°, 30°, 32°, 34°, 35°, 36°, 38°, 40°, 42°, 44°, 45°, 46°, 48° or 50°, or other values ​​within the above range. This application embodiment does not limit this.

[0087] Optionally, the angle formed between any reflective bevel and the surface of the solder strip 10 is 50°-80°, specifically 50°, 52°, 54°, 55°, 56°, 58°, 60°, 62°, 64°, 65°, 66°, 68°, 70°, 72°, 74°, 75°, 76°, 78° or 80°, or other values ​​within the above range. This application embodiment does not limit this.

[0088] In this embodiment, when all reflective protrusions 1 are reflective pyramids, all reflective pyramids can be regular pyramids. All regular pyramid structures can be regular triangular pyramids, regular square pyramids, regular pentagonal pyramids, regular hexagonal pyramids, or combinations of at least two of these structures. When all reflective protrusions 1 are reflective pyramids, all reflective pyramids can also be asymmetrical pyramids. All asymmetrical pyramids can be triangular pyramids, regular square pyramids, regular pentagonal pyramids, or regular hexagonal pyramids, or combinations of at least two of these structures. When all reflective protrusions 1 are reflective pyramids, they can also be a combination of regular pyramids and asymmetrical pyramids.

[0089] The following example illustrates the specific structure of the reflective protrusion 1, using a photovoltaic module comprising a solder strip 10 and photovoltaic cells 20 installed in the Northern Hemisphere with an installation tilt angle (the angle between the photovoltaic module and the ground) of 0°-60°. The optical path diagram of sunlight incident on the photovoltaic module is shown below. Figure 4 As shown, when the solder ribbon 10 does not have reflective protrusions 1, the first incident light ray a1, after illuminating the surface of the solder ribbon 10 (the structure shown by the dotted line in the figure), will be reflected by the surface of the solder ribbon 10 to form a first reflected light ray b1. The first reflected light ray b1 will be reflected by the cover plate 40 to form a second reflected light ray c1, and the second reflected light ray c1 will finally be incident on the surface of the photovoltaic cell 20. When the solder ribbon 10 has reflective protrusions 1, the second incident light ray a2, after illuminating the surface of the reflective protrusions 1, will be reflected by the surface of the reflective protrusions 1 to form a second reflected light ray b2, and the second reflected light ray b2 can directly be incident on the surface of the photovoltaic cell 20. In other words, when the surface of the solder ribbon 10 has reflective protrusions 1, it can not only improve the utilization rate of the incident light by the photovoltaic cell 20, but also reduce the secondary reflection of the incident light, thereby reducing the light loss when the incident light is transmitted inside the photovoltaic module.

[0090] In addition, such as Figure 4 As shown, the reflective protrusion 1 can be formed by removing a portion of the surface of the solder ribbon 10. In this way, compared with the solder ribbon 10 without the reflective protrusion 1, the width of the area formed by the solder ribbon 10 with the reflective protrusion 1 on the surface of the photovoltaic cell 20 can be reduced from d1 to d2, thereby reducing the shading area of ​​the solder ribbon 10 on the photovoltaic cell 20, which is beneficial to further improve the utilization rate of the photovoltaic cell 20 for incident light.

[0091] In one specific implementation, such as Figure 5As shown, the solder ribbon 10 includes a substrate 2 and a reflective film 3, with the reflective film 3 covering the surface of the substrate 2. Along the height direction Z of the solder ribbon 10, reflective protrusions 1 are disposed on the surface of the reflective film 3 away from the substrate 2; that is, the reflective protrusions 1 are formed by removing a portion of the surface of the reflective film 3. The substrate 2 has excellent electrical conductivity, and the reflective film 3 has high reflectivity. By placing the reflective protrusions 1 on the reflective film 3, the reflectivity of the reflective protrusions 1 can be further improved. The substrate 2 can be made of copper, and the reflective film 3 can cover the entire surface of the substrate 2 circumferentially. Therefore, the reflective film 3 also protects the substrate 2, reducing the risk of oxidation and corrosion, which is beneficial to improving the electrical reliability and service life of the solder ribbon 10.

[0092] In another specific implementation, such as Figure 1 As shown, the welding strip 10 includes a substrate 2, and a reflective protrusion 1 is disposed on one side surface of the substrate 2 along its height direction Z. That is, the reflective protrusion 1 is formed by removing a part of the surface of the substrate 2. Such an integral structure is beneficial to improving the structural strength of the welding strip 10. The reflective protrusion 1 is not easy to fall off, so that the welding strip 10 has higher mechanical reliability and longer service life.

[0093] In this embodiment, to improve the reflectivity of the solder ribbon 10, a silver plating layer can be applied to the entire surface of the substrate 2. The silver plating layer has high reflectivity, which is beneficial for further improving the utilization rate of incident light by the photovoltaic cell 20. Furthermore, the silver plating layer has good electrical conductivity; when it covers the entire surface of the substrate 2 circumferentially, it can improve the conductivity of the solder ribbon 10. A micro-pyramidal structure can be formed on the surface of the silver plating layer. This structure allows light to undergo secondary reflection between the solder ribbon 10 and the photovoltaic cell 20, thereby further improving the utilization rate of incident light by the photovoltaic cell 20.

[0094] In the above embodiments, the width W4 of the solder ribbon 10 is 0.1mm-0.6mm. Maintaining the width W4 within this range avoids the situation where the solder ribbon 10 is too wide, resulting in an excessively large shading area on the photovoltaic cell 20, and also avoids the situation where the solder ribbon 10 is too narrow, resulting in insufficient mechanical strength and excessive resistance. Therefore, when the width W4 of the solder ribbon 10 is 0.1mm-0.6mm, it ensures that the solder ribbon 10 has sufficient mechanical strength and low resistance, while reducing the shading area on the photovoltaic cell 20 and appropriately reducing the cost of the solder ribbon 10.

[0095] Preferably, W4 is 0.1mm-0.3mm, and W4 can specifically be 0.11mm, 0.12mm, 0.13mm, 0.14mm, 0.15mm, 0.16mm, 0.17mm, 0.18mm, 0.19mm, 0.2mm, 0.21mm, 0.22mm, 0.23mm, 0.24mm, 0.25mm, 0.26mm, 0.27mm, 0.28mm, 0.29mm or 0.3mm, or other values ​​within the above range. This application embodiment does not limit this.

[0096] Preferably, W4 is 0.3mm-0.6mm, and W4 can specifically be 0.31mm, 0.32mm, 0.33mm, 0.34mm, 0.35mm, 0.36mm, 0.37mm, 0.38mm, 0.39mm, 0.4mm, 0.41mm, 0.42mm, 0.43mm, 0.44mm, 0.45mm, 0.46mm, 0.47mm, 0.48mm, 0.49mm, 0.5mm, 0.51mm, 0.52mm, 0.53mm, 0.54mm, 0.55mm, 0.56mm, 0.57mm, 0.58mm, 0.59mm, or 0.6mm, or other values ​​within the above range. This application embodiment does not limit this.

[0097] In the above embodiments, the height H4 of the solder ribbon 10 is 0.1mm-0.3mm. Maintaining the height H4 within this range avoids excessive rigidity due to an excessively large height of the solder ribbon 10, thereby reducing the stress exerted by the solder ribbon 10 on the photovoltaic cell 20 during welding. It also avoids insufficient mechanical strength and excessive resistance of the solder ribbon 10 due to an excessively small height. Therefore, when the height H4 of the solder ribbon 10 is 0.1mm-0.3mm, it ensures sufficient mechanical strength and low resistance, while also appropriately reducing the cost of the solder ribbon 10.

[0098] Preferably, H4 is 0.1mm-0.3mm, and H4 can specifically be 0.11mm, 0.12mm, 0.13mm, 0.14mm, 0.15mm, 0.16mm, 0.17mm, 0.18mm, 0.19mm, 0.2mm, 0.21mm, 0.22mm, 0.23mm, 0.24mm, 0.25mm, 0.26mm, 0.27mm, 0.28mm, 0.29mm or 0.3mm, or other values ​​within the above range. This application embodiment does not limit this.

[0099] The following example illustrates the structure of the reflective protrusion 1, using a photovoltaic module containing a solder strip 10 and a photovoltaic cell 20 installed in the Northern Hemisphere, with the installation tilt angle (the angle between the photovoltaic module and the ground) being 0°-60°.

[0100] When the reflective protrusion 1 is an asymmetrical reflective pyramid and the asymmetrical reflective pyramid is a triangular pyramid, the structural schematic diagram of the solder strip 10 is as follows: Figure 6 As shown in the figure (only one reflective protrusion 1 is shown as an example), the triangular pyramid includes three inclined planes: ABD, ACD, and ABC. The base BD of plane ABD is perpendicular to the length direction Y of the solder strip 10. Specifically, the angles formed between plane ABD and the surface of the solder strip 10 are 20°-60°, the angles formed between plane ACD and the surface of the solder strip 10 are 30°-80°, and the angles formed between plane ABC and the surface of the solder strip 10 are 30°-80°. Furthermore, the angles formed between the three inclined planes ABD, ACD, and ABC and the surface of the solder strip 10 are not equal. When the angles formed between the three inclined planes ABD, ACD, and ABC and the surface of the solder strip 10 meet the above ranges, the triangular pyramid structure can accommodate changes in the azimuth and altitude angles of sunlight at more times, thereby improving the refraction efficiency of the solder strip 10 for incident sunlight throughout the day's illumination, and thus improving the light utilization rate of the photovoltaic cell 20.

[0101] Optionally, the included angle formed by surface ABD and the surface of solder strip 10 can be 20°, 25°, 30°, 35°, 40°, 45°, 50°, 55° or 60°, or other values ​​within the above range. This application embodiment does not limit this.

[0102] Optionally, the included angle formed by surface ACD and the surface of solder strip 10 can be 30°, 35°, 40°, 45°, 50°, 55°, 60°, 65°, 70°, 75° or 80°, or other values ​​within the above range. This application embodiment does not limit this.

[0103] Optionally, the included angle formed by surface ABC and the surface of the solder strip 10 can be 30°, 35°, 40°, 45°, 50°, 55°, 60°, 65°, 70°, 75° or 80°, or other values ​​within the above range. This application embodiment does not limit this.

[0104] When the reflective protrusion 1 is an asymmetrical reflective pyramid and the asymmetrical reflective pyramid is a square pyramid, the structural schematic diagram of the solder strip 10 is as follows: Figure 7As shown (only one reflective protrusion 1 is shown in the figure). The square pyramid includes four inclined planes: EIH, EHG, EFG, and EFI. The diagonal GI of the base of the square pyramid is parallel to the length direction Y of the solder strip 10. Specifically, the angles formed by EIH and the surface of the solder strip 10 are 30°-80°, EHG and EFG are 20°-70°, and EFI and EFI are 30°-80°. The angles formed by the four inclined planes EIH, EHG, EFG, and EFI and the surface of the solder strip 10 are all unequal. When the angles formed by the four inclined planes EIH, EHG, EFG and EFI and the surface of the solder strip 10 meet the above range, the quadrangular pyramid structure can match the changes in the azimuth angle and solar altitude angle of the sun at more times, thereby improving the refraction efficiency of the solder strip 10 for the incident sunlight throughout the day, which in turn helps to improve the utilization rate of light by the photovoltaic cell 20.

[0105] Optionally, the included angle formed by surface EIH and surface of solder strip 10 can be 30°, 35°, 40°, 45°, 50°, 55°, 60°, 65°, 70°, 75° or 80°, or other values ​​within the above range. This application embodiment does not limit this.

[0106] Optionally, the included angle formed by the surface EHG and the surface of the solder strip 10 can be 20°, 25°, 30°, 35°, 40°, 45°, 50°, 55°, 60°, 65° or 70°, or other values ​​within the above range. This application embodiment does not limit this.

[0107] Optionally, the included angle formed by the surface EFG and the surface of the solder strip 10 can be 20°, 25°, 30°, 35°, 40°, 45°, 50°, 55°, 60°, 65° or 70°, or other values ​​within the above range. This application embodiment does not limit this.

[0108] Optionally, the included angle formed by the surface EFI and the surface of the solder strip 10 can be 30°, 35°, 40°, 45°, 50°, 55°, 60°, 65°, 70°, 75° or 80°, or other values ​​within the above range. This application embodiment does not limit this.

[0109] When the reflective protrusion 1 is an asymmetrical reflective pyramid and the asymmetrical reflective pyramid is a pentagonal pyramid, the structural schematic diagram of the solder strip 10 is as follows: Figure 8As shown in the figure (only one reflective protrusion 1 is shown as an example), the pentagonal pyramid includes five inclined planes: JNM, JML, JLK, JKO, and JON. The base LK of plane JLK is perpendicular to the length direction Y of the solder strip 10. Specifically, the angles formed between plane JNM and the surface of solder strip 10 are 40°-80°, JML is 30°-70°, JLK is 20°-60°, JKO is 30°-70°, and JON is 40°-80°. Furthermore, the angles formed between the five inclined planes JNM, JML, JLK, JKO, and JON and the surface of solder strip 10 are all unequal. When the angles formed by the five inclined planes JNM, JML, JLK, JKO, and JON with the surface of the welding strip 10 meet the above range, the pentagonal pyramid structure can match the changes in the azimuth and altitude angles of the sun's rays at more times, thereby improving the refraction efficiency of the welding strip 10 for the incident sunlight throughout the day, which in turn helps to improve the utilization rate of light by the photovoltaic cell 20.

[0110] Optionally, the included angle formed by the surface JNM and the surface of the solder strip 10 can be 40°, 45°, 50°, 55°, 60°, 65°, 70°, 75° or 80°, or other values ​​within the above range. This application embodiment does not limit this.

[0111] Optionally, the included angle formed by surface JML and surface of solder strip 10 can be 30°, 35°, 40°, 45°, 50°, 55°, 60°, 65° or 70°, or other values ​​within the above range. This application embodiment does not limit this.

[0112] Optionally, the included angle formed by the surface JLK and the surface of the solder strip 10 can be 20°, 25°, 30°, 35°, 40°, 45°, 50°, 55° or 60°, or other values ​​within the above range. This application embodiment does not limit this.

[0113] Optionally, the included angle formed by surface JKO and surface of solder strip 10 can be 30°, 35°, 40°, 45°, 50°, 55°, 60°, 65° or 70°, or other values ​​within the above range. This application embodiment does not limit this.

[0114] Optionally, the included angle formed by the surface JON and the surface of the solder strip 10 can be 40°, 45°, 50°, 55°, 60°, 65°, 70°, 75° or 80°, or other values ​​within the above range. This application embodiment does not limit this.

[0115] When the reflective protrusion 1 is an asymmetrical reflective pyramid and the asymmetrical reflective pyramid is a hexagonal pyramid, the structural schematic diagram of the solder strip 10 is as follows: Figure 9 As shown (only one reflective protrusion 1 is shown in the figure). The hexagonal pyramid includes six inclined planes: PUT, PTR, PRQ, PQW, PWV, and PVU. The bottom edge RQ of PRQ is perpendicular to the length direction Y of the solder strip 10. Specifically, the angles formed between the surface PUT and the surface of the solder strip 10 are 40°-80°, the angles formed between the surface PTR and the surface of the solder strip 10 are 30°-70°, the angles formed between the surface PRQ and the surface of the solder strip 10 are 20°-60°, the angles formed between the surface PQW and the surface of the solder strip 10 are 30°-70°, the angles formed between the surface PWV and the surface of the solder strip 10 are 40°-80°, and the angles formed between the surface PVU and the surface of the solder strip 10 are 20°-80°. Furthermore, the angles formed between the six inclined surfaces (PUT, PTR, PRQ, PQW, PWV, and PVU) and the surface of the solder strip 10 are all unequal. When the angles formed by the six inclined planes—PUT, PTR, PRQ, PQW, PWV, and PVU—with the surface of the solder strip 10 meet the above-mentioned range, the hexagonal pyramid structure can match the changes in the azimuth and altitude angles of sunlight at more times, thereby improving the refraction efficiency of the solder strip 10 for incident sunlight throughout the day, which in turn helps to improve the utilization rate of light by the photovoltaic cell 20.

[0116] Optionally, the included angle formed by the surface PUT and the surface of the solder strip 10 can be 40°, 45°, 50°, 55°, 60°, 65°, 70°, 75° or 80°, or other values ​​within the above range. This application embodiment does not limit this.

[0117] Optionally, the included angle formed by the surface PTR and the surface of the solder strip 10 can be 30°, 35°, 40°, 45°, 50°, 55°, 60°, 65° or 70°, or other values ​​within the above range. This application embodiment does not limit this.

[0118] Optionally, the included angle formed by the surface PRQ and the surface of the solder strip 10 can be 20°, 25°, 30°, 35°, 40°, 45°, 50°, 55° or 60°, or other values ​​within the above range. This application embodiment does not limit this.

[0119] Optionally, the included angle formed by the surface PQW and the surface of the solder strip 10 can be 30°, 35°, 40°, 45°, 50°, 55°, 60°, 65° or 70°, or other values ​​within the above range. This application embodiment does not limit this.

[0120] Optionally, the included angle formed by the surface PWV and the surface of the solder strip 10 can be 40°, 45°, 50°, 55°, 60°, 65°, 70°, 75° or 80°, or other values ​​within the above range. This application embodiment does not limit this.

[0121] Optionally, the included angle formed by the surface PVU and the surface of the solder strip 10 can be 20°, 25°, 30°, 35°, 40°, 45°, 50°, 55°, 60°, 65°, 70°, 75° or 80°, or other values ​​within the above range. This application embodiment does not limit this.

[0122] This application also provides a photovoltaic module, such as... Figure 10 As shown, the photovoltaic module includes multiple cell strings, each cell string including the aforementioned solder ribbon 10 and multiple photovoltaic cells 20. Adjacent photovoltaic cells 20 are electrically connected via the solder ribbon 10. The photovoltaic module also includes an encapsulation layer 30 and a cover plate 40. The encapsulation layer 30 covers the light-facing and back-facing surfaces of the cell strings, and the cover plate 40 covers the surface of the encapsulation layer 30 away from the cell strings. During the lamination process of the photovoltaic module, the encapsulation layer 30 encapsulates and protects the photovoltaic cells 20 and solder ribbon 10, preventing external environmental factors from affecting their performance. It also bonds the cover plate 40, photovoltaic cells 20, and solder ribbon 10 into a single unit. The cover plate 40 can be made of one of the following rigid materials: tempered glass, polyethylene terephthalate (PET), polycarbonate (PC); or one of the following flexible materials: polyvinyl fluoride (PVF), ethylene-tetrafluoroethylene copolymer (ETFE), polyvinylidene fluoride (PVDF). The encapsulation layer 30 is an adhesive film, which can be made of one of the following materials: ethylene-vinyl acetate copolymer (EVA), polyolefin elastomer (POE), polyvinyl butyral (PVB). The encapsulation layer 30 can also be an EPE film (EVA-POE-EVA co-extruded structure) or an EP film (EVA-POE co-extruded structure).

[0123] In one specific embodiment, the photovoltaic cell 20 is a bifacial cell, which can be one of the following: an emitter-back passivated cell (PERC), a tunnel oxide passivated contact cell (TOPCon), an intrinsic thin-film heterojunction cell (HJT), or a perovskite cell.

[0124] For PERC cells, along their thickness direction, the PERC cell sequentially includes a front-surface silver electrode, a front-surface silicon nitride passivation layer, a phosphorus emitter layer, a P-type substrate silicon layer, a localized aluminum back field, a metallic aluminum back electrode, and a back passivation layer (Al2O3 / SiNx). PERC cells use a passivation film to passivate the back side, replacing the all-aluminum back field, enhancing light reflection within the silicon substrate, reducing the recombination rate on the back side, and improving the cell efficiency by 0.5%-1%.

[0125] For TOPCon cells, along their thickness direction, the TOPCon cell sequentially includes a silver electrode, a front-surface silicon nitride passivation layer, a boron-doped emitter, an N-type substrate silicon layer, a diffused doped layer, an ultrathin silicon oxide layer, doped polycrystalline silicon, silicon nitride, and the silver electrode. The back of the cell consists of an ultrathin silicon oxide layer (1nm~2nm) and a phosphorus-doped microcrystalline amorphous mixed Si film, which together form a passivation contact structure. This structure can block minority carrier recombination, increasing the cell's open-circuit voltage and short-circuit current. The ultrathin oxide layer allows majority carrier electrons to tunnel into the polycrystalline silicon layer while blocking minority carrier recombination. The excellent passivation effect of the ultrathin silicon oxide and heavily doped silicon film causes band bending on the silicon wafer surface, resulting in a field passivation effect. This significantly increases the probability of electron tunneling, reduces contact resistance, and improves the cell's open-circuit voltage and short-circuit current, thereby increasing the cell's conversion efficiency.

[0126] For an HJT cell, along its thickness direction, the HJT cell sequentially includes a front low-temperature silver electrode, a front conductive film, an N-type amorphous silicon film, an intrinsic amorphous silicon film, an N-type substrate silicon layer, an intrinsic amorphous silicon film, a P-type amorphous silicon film, a back conductive film, and a back low-temperature silver electrode.

[0127] For a perovskite solar cell, along its thickness direction, it sequentially comprises a substrate material, a conductive thin film, an electron transport layer (titanium dioxide), a perovskite absorption layer (hole transport layer), and a metal cathode. Perovskite materials possess a high light absorption coefficient and a long carrier diffusion distance. After the photons absorbed by the perovskite material are converted into electrons, they are easily collected by the electrodes with minimal loss, thus generating high photogenerated voltage and current, resulting in high photoelectric conversion efficiency.

[0128] The cover plate 40 specifically includes an upper cover plate 401 located on the light-facing side of the photovoltaic cell 20 and a lower cover plate 402 located on the back-facing side of the photovoltaic cell 20. For example... Figure 10 As shown, when the photovoltaic cell 20 is a bifacial cell, one end of the solder ribbon 10 along the length direction Y is welded and fixed to the light-facing side of one photovoltaic cell 20, and the other end is welded and fixed to the back-facing side of an adjacent photovoltaic cell 20. Along the thickness direction Z of the photovoltaic module, the solder ribbon 10 can have reflective protrusions 1 only on the side facing the upper cover plate 401 to improve the utilization rate of sunlight by the photovoltaic cell 20. Alternatively, along the thickness direction Z of the photovoltaic module, the solder ribbon 10 can also have reflective protrusions 1 on both sides of its surface, which not only improves the utilization rate of sunlight by the photovoltaic cell 20 but also improves the utilization rate of ground-reflected light, thereby improving the bifaciality of the photovoltaic cell 20 and consequently improving the output power of the photovoltaic module.

[0129] In another specific embodiment, the photovoltaic cell 20 is a back contact cell, specifically one of the following: interdigitated back contact (IBC), heterojunction back contact (HBC), and tunnel oxide back contact (TBC).

[0130] For an IBC cell, along its thickness direction, it sequentially includes a silicon nitride anti-reflection layer, an N+ front surface field, an N-type substrate silicon layer, a P+ emitter, an N+ back field, an aluminum oxide passivation layer, a silicon nitride anti-reflection layer, and a silver electrode. IBC cells utilize ion implantation technology to obtain P- and N-regions with good uniformity and precisely controllable junction depth. The absence of grid lines on the front side eliminates light-blocking current loss from the metal electrodes, maximizing the utilization of incident photons and improving short-circuit current by approximately 7% compared to conventional solar cells. Due to its back-contact structure, grid line shading is not a concern, allowing for a wider grid line ratio, thus reducing series resistance and achieving a high fill factor. Optimized design of surface passivation and light-trapping structures can be achieved, resulting in lower front-surface recombination rates and surface reflection.

[0131] HBC cells effectively combine the advantages of IBC and heterojunction cells. Their front surface passivation layer uses hydrogenated amorphous silicon, while N-type and P-type amorphous silicon films are deposited on the back side to form a heterojunction. HBC cells fully utilize the superior surface passivation properties of amorphous silicon, and the heterojunction structure formed on the back side exhibits excellent passivation, enabling the simultaneous achievement of higher short-circuit current and open-circuit voltage, thereby improving photoelectric conversion efficiency.

[0132] For TBC cells, the advantages of TOPCon's tunneling oxide layer technology and IBC back-side electrode arrangement are combined, resulting in significantly improved passivation and open-circuit voltage, achieving higher cell conversion efficiency while maintaining economic viability. The complete production process of TBC cells mainly includes depositing tunneling oxide and P+ polycrystalline silicon, depositing passivation films, and printing electrodes on the back of the silicon wafer. Based on the TOPCon production process, TBC cells require additional back-side electrode processes such as masking, laser grooving, PN region fabrication, and etching. Masking is mainly done using APCVD or PECVD, PN region fabrication is mainly done using PECVD, etching mainly uses traditional wet processing equipment, and grooving is performed using laser equipment.

[0133] Alternatively, the photovoltaic cell 20 can be a back-contact tandem cell, comprising a back-contact bottom cell and a perovskite top cell, with the perovskite top cell electrically connected to the light-facing surface of the back-contact bottom cell. The back-contact bottom cell can be one of IBC, HBC, or TBC cells. The perovskite top cell is a thin-film solar cell using perovskite material as the photoactive layer. The structure of the perovskite top cell mainly consists of the following key components: a transparent conductive substrate, an electron transport layer, a perovskite light-absorbing layer, a hole transport layer, and a metal electrode. These components work together to enable the perovskite top cell to effectively absorb sunlight and convert it into electrical energy. The perovskite material in the light-absorbing layer has excellent light absorption performance, absorbing a wider spectral range and effectively converting short-wavelength spectra, giving the perovskite top cell high photoelectric conversion efficiency.

[0134] The cover plate 40 specifically includes an upper cover plate 401 located on the light-facing side of the photovoltaic cell 20 and a lower cover plate 402 located on the back-facing side of the photovoltaic cell 20. For example... Figure 11 As shown, when the photovoltaic cell 20 is a back-contact cell or a back-contact tandem cell, the two ends of the solder ribbon 10 along the length direction Y are respectively welded and fixed to the back surface of two adjacent photovoltaic cells 20. Along the thickness direction Z of the photovoltaic module, the solder ribbon 10 has reflective protrusions 1 on the side facing the lower cover plate 402, which can improve the utilization rate of ground reflected light by the photovoltaic cell 20, thereby helping to improve the output power of the photovoltaic module.

[0135] In some embodiments, such as Figure 12As shown, the photovoltaic cell 20 has an edge region 202 and a main region 201. Edge regions 202 are provided on both sides of the main region 201 along the width direction X of the photovoltaic cell 20. Since the current density of the edge region 202 is lower than that of the main region 201, the following configuration can be made: the height of any reflective protrusion 1 on the solder ribbon 10 located in the edge region 202 is greater than the height of any reflective protrusion 1 on the solder ribbon 10 located in the main region 201. This allows the reflective protrusion 1 on the solder ribbon 10 in the edge region 202 to reflect more incident light onto the surface of the photovoltaic cell 20, enhancing light absorption in the edge region 202. This, in turn, helps to increase the current density of the edge region 202, making the overall current density distribution of the photovoltaic cell 20 more uniform and balanced, thereby improving the photoelectric conversion efficiency of the photovoltaic cell 20.

[0136] Preferably, along the width direction X of the photovoltaic cell 20, the ratio of the width L1 of the edge region 202 to the width L2 of the photovoltaic cell 20 satisfies 0.1 ≤ L1:L2 ≤ 0.3. That is, in this embodiment, the region extending 10%-30% from the edge of the photovoltaic cell 20 towards its center is defined as the edge region 202. When the width L1 of the edge region 202 meets the above range, it can be ensured that the edge region 202 fully covers the area with low current density on the photovoltaic cell 20, while avoiding unnecessary processing of the area with high current density due to an excessively large coverage area of ​​the edge region 202.

[0137] Optionally, the values ​​of L1:L2 can be 0.1, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, 0.19, 0.2, 0.21, 0.22, 0.23, 0.24, 0.25, 0.26, 0.27, 0.28, 0.29 or 0.3, or other values ​​within the above range. This application embodiment does not limit these values.

[0138] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A welding strip, characterized in that, The welding strip (10) has reflective protrusions (1) on at least one side surface along its height direction, and a plurality of the reflective protrusions (1) are arranged in an array. In the width direction of the solder strip (10), along the direction from the center of the solder strip (10) to its two ends, the height of the plurality of reflective protrusions (1) increases sequentially; At least one of the reflective protrusions (1) is a reflective pyramid, the reflective pyramid having at least three reflective bevels, each of the reflective bevels forming an angle with the surface of the solder strip (10) that is not equal to the others.

2. The welding strip according to claim 1, characterized in that, Along the width direction of the solder strip (10), the gap between two adjacent reflective protrusions (1) is less than 60 μm; And / or, along the length direction of the solder strip (10), the gap between two adjacent reflective protrusions (1) is less than 100 μm.

3. The welding strip according to claim 1, characterized in that, Along the height direction of the welding strip (10), the height of the reflective protrusion (1) is 30μm-100μm.

4. The welding strip according to claim 1, characterized in that, In the array of the reflective protrusions (1), when an odd number of the reflective protrusions (1) are arranged along the width direction of the solder strip (10), the geometric center of the bottom surface of the reflective protrusion (1) located in the center is located on the center line of the width direction of the solder strip (10). In the array of reflective protrusions (1), when an even number of reflective protrusions (1) are arranged along the width direction of the solder strip (10), the distance from the geometric center of the bottom surface of the two reflective protrusions (1) located at the center to the center line of the width direction of the solder strip (10) is equal.

5. The welding strip according to claim 1, characterized in that, The reflective protrusion (1) includes a first reflective protrusion (11), a second reflective protrusion (12) and a third reflective protrusion (13). The first reflective protrusion (11), the second reflective protrusion (12) and the third reflective protrusion (13) are arranged sequentially in the width direction of the solder strip (10) along the direction from the center of the solder strip (10) to its two ends. Along the height direction of the welding strip (10), the height H1 of the first reflective protrusion (11) is 10μm-50μm, the height H2 of the second reflective protrusion (12) is 15μm-70μm, and the height H3 of the third reflective protrusion (13) is 20μm-100μm, and H1 < H2 < H3; And / or, along the width direction of the solder strip (10), the width W1 of the first reflective protrusion (11) is 50μm-300μm, the width W2 of the second reflective protrusion (12) is 20μm-200μm, and the width W3 of the third reflective protrusion (13) is 5μm-100μm.

6. The welding strip according to claim 1, characterized in that, The welding strip (10) includes a substrate (2) and a reflective film (3), the reflective film (3) covering the surface of the substrate (2); Along the height direction of the welding strip (10), the reflective protrusion (1) is disposed on the side surface of the reflective film (3) away from the substrate (2).

7. The welding strip according to any one of claims 1-6, characterized in that, The welding strip (10) includes a substrate (2), and the reflective protrusion (1) is disposed on one side surface of the substrate (2) along its height direction.

8. The welding strip according to claim 1, characterized in that, The angle between any of the reflective bevels and the surface of the welding strip (10) is 20°-80°.

9. The welding strip according to claim 1, characterized in that, The reflective pyramid is one of the following: triangular pyramid, square pyramid, pentagonal pyramid, or hexagonal pyramid.

10. A photovoltaic module, characterized in that, include: A battery string, comprising a solder strip as described in any one of claims 1-9 and a plurality of photovoltaic cells (20), wherein two adjacent photovoltaic cells (20) are connected by the solder strip (10); Encapsulation layer (30) is used to cover the surface of the battery string; A cover plate (40) is used to cover the surface of the encapsulation layer (30) away from the battery string; In this case, along the thickness direction of the photovoltaic module, the surface of the solder strip (10) with the reflective protrusion (1) is positioned facing the cover plate (40).

11. The photovoltaic module according to claim 10, characterized in that, The photovoltaic cell (20) has an edge region (202) and a main body region (201). Along the width direction of the photovoltaic cell (20), the edge region (202) is provided on both sides of the main body region (201). Along the width direction of the photovoltaic cell (20), the ratio of the width L1 of the edge region (202) to the width L2 of the photovoltaic cell (20) satisfies 0.1≤L1:L2≤0.3; The height of any of the reflective protrusions (1) on the solder strip (10) located in the edge region (202) is greater than the height of any of the reflective protrusions (1) on the solder strip (10) located in the main body region (201).

Images