Interconnected solder strip

Abstract

The application belongs to the technical field of photovoltaics. The application discloses an interconnected solder strip, which comprises a core layer, a conductive layer and an outer layer. The core layer comprises a polymer material; the conductive layer is arranged on the outer side of the core layer; and the outer layer is arranged on the outer side of the conductive layer, and the outer layer comprises at least one of a low-temperature metal or a low-temperature alloy. In the application, the polymer material is used as the core layer of the interconnected solder strip, so that the stress of the interconnected solder strip at the bending position is reduced, and the extrusion stress between the solder strip and the battery piece is reduced. The problem that the stress and the extrusion stress are too large when the interconnected solder strip is bent, which leads to the hidden cracking or fragmentation of the battery piece, is solved, and the reliability of the photovoltaic module is improved.

Description

Technical Field

[0001] This invention belongs to the field of photovoltaic technology, and particularly relates to an interconnecting solder strip. Background Technology

[0002] Interconnect ribbons are conductive leads in solar cells. They lead out the electrical energy converted from light energy onto the silicon wafer and transmit it to electrical equipment. They also serve as heat dissipation and mechanical components, making them one of the most important functional components of solar photovoltaic cells.

[0003] Currently, crystalline silicon solar cell modules are basically connected in series using tin-plated copper solder strips. The solder strips are welded to the front of the cell and then extend to the back of the adjacent cell.

[0004] However, in the process of implementing the technical solutions in the embodiments of this application, the inventors of this application discovered that the above-mentioned technology has at least the following technical problems:

[0005] Although copper has good ductility, if the gaps between solar cells are shortened, significant stress will exist at the bends. During module lamination, the compressive stress exerted by the solder ribbons on the solar cells at the bends is substantial, easily causing microcracks or even cell breakage. At non-bend areas, the compressive stress between the solder ribbons and the solar cells also increases the risk of microcracks or cell breakage. Summary of the Invention

[0006] This application provides an interconnecting solder strip that solves the problems of high stress on the solder strip and high compressive stress on the battery in the prior art, ensuring that the battery cells will not have microcracks or breakage, and improving the reliability of the module.

[0007] One aspect of this application provides an interconnecting solder strip, which includes a core layer, a conductive layer, and an outer layer; the core layer includes a polymer material; the conductive layer is disposed outside the core layer; the outer layer is disposed outside the conductive layer, and the outer layer includes at least one of a low-temperature metal or a low-temperature alloy.

[0008] Furthermore, the cross-section of the core layer is at least one of a circle, a rectangle, or a triangle.

[0009] Furthermore, when the cross-section of the core layer is circular, the diameter of the conductive layer is D, and the diameter of the core layer is d; where 1-δ 4 <0.95, δ=d / D.

[0010] Furthermore, when the cross-section of the core layer is rectangular or triangular, the rectangular width or triangular base length of the conductive layer is B, the rectangular height or triangular height of the conductive layer is H, the rectangular width or triangular base length of the core layer is b, and the rectangular height or triangular height of the core layer is h.

[0011] Wherein, 1-αβ 3<0.95, α=b / B, β=h / H.

[0012] Furthermore, the polymer material has a melting point greater than or equal to 140°C.

[0013] Furthermore, the polymer material includes at least one of PP, PC, PET or PA.

[0014] Furthermore, the melting point of the low-temperature metal or low-temperature alloy is less than or equal to 180°C;

[0015] Preferably, the low-temperature alloy includes at least one of tin-lead alloy, tin-bismuth-silver alloy, tin-indium alloy, or tin-lead-indium alloy.

[0016] Furthermore, the conductive layer comprises an alloy of one or at least two of copper, silver, or aluminum.

[0017] Furthermore, the cross-sectional area of ​​the conductive layer is S1, the cross-sectional area of ​​the core layer is S2, and the ratio of S1 to S2, S1 / S2, is greater than or equal to 1.

[0018] Another aspect of this application provides a photovoltaic module comprising at least one first cell, at least one second cell, and interconnecting ribbons as described above, the interconnecting ribbons being used to connect the first cell and the second cell.

[0019] In summary, the embodiments of this application have at least the following beneficial effects:

[0020] The interconnecting ribbon in this application uses a polymer as the core layer, which reduces the stress of the interconnecting ribbon at the bending point and also reduces the extrusion stress between the ribbon and the cell, preventing the cell from microcracking or breaking during the lamination process and improving the reliability of the module. Attached Figure Description

[0021] Figure 1 This is a cross-sectional structural diagram of one implementation of the interconnect solder strip in this application;

[0022] Figure 2 A cross-sectional structural diagram of one welding method for battery cells;

[0023] Figure 3 This is a cross-sectional structural diagram of another implementation of the interconnecting solder strip in this application;

[0024] Figure 4 This is a cross-sectional structural diagram of another implementation of the interconnecting solder strip in this application;

[0025] Figure 5 This is a cross-sectional structural diagram of another implementation of the interconnecting solder strip in this application;

[0026] Figure 6This is a cross-sectional structural diagram of one implementation of the photovoltaic module in this application;

[0027] Figure 7 This is a schematic diagram of the cross-sectional structure of the interconnecting solder strip in Comparative Example 1;

[0028] Figure 8 This is a schematic diagram of the cross-sectional structure of the interconnecting solder strip in Comparative Example 2.

[0029] In the figure: interconnecting ribbon 100, core layer 11, conductive layer 12, outer layer 13, adhesive layer 14; solar cell 200, first solar cell 21, second solar cell 22; photovoltaic module 300, front substrate 31, front encapsulation film 32, solar cell layer 33, rear encapsulation film 34, rear substrate 35. Detailed Implementation

[0030] To enable those skilled in the art to better understand the present invention, the technical solutions in specific embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0031] To address the problem that in existing technologies using tin-plated copper solder strips to weld solar cells, the high compressive stress exerted by the solder strips on the cells during lamination can easily cause microcracks or even cell breakage, this application proposes an interconnecting solder strip with a polymer material as the core layer. This material has high ductility and toughness, and lower stress at bending points and compressive stress, ensuring that the solar cells will not develop microcracks and improving the reliability of the module.

[0032] This application provides a method such as Figure 1 The interconnecting solder strip 100 shown includes a core layer 11, a conductive layer 12, and an outer layer 13. The core layer 11 includes a polymer material, the conductive layer 12 is disposed on the outer layer 13 of the core layer 11, and the outer layer 13 is disposed outside the conductive layer 12. The outer layer 13 includes at least one of a low-temperature metal or a low-temperature alloy.

[0033] like Figure 2As shown, in the connection of the cell string 200 of a crystalline silicon solar cell module, one end of the interconnecting solder ribbon 100 is typically soldered to the front side of the first cell 21, and the other end of the interconnecting solder ribbon 100 is soldered to the back side of the second cell 22. When connected in series in this way, the interconnecting solder ribbon 100 will have a large bend at the gap between the first cell 21 and the second cell 22. The solder ribbon used in the prior art is usually tin-plated copper strip. Although copper has good ductility, it will also generate large stress under large bends. During the lamination process, the bends of the tin-plated copper strip will cause large compressive stress on the cell string 200, which can easily lead to microcracks and breakage of the cells. The compressive stress between the tin-plated copper strip and the cells at non-bends will also increase the risk of microcracks and breakage of the cells. As the cell string 200 is developing towards thinner sheets, the maximum stress that the cell string 200 can withstand is reduced. If tin-plated copper strip is still used, the cell string 200 is very likely to develop microcracks and breakage. This application proposes an interconnecting ribbon 100, whose core layer 11 includes a polymer material, which greatly improves the ductility of the interconnecting ribbon 100 and reduces the stress at the bending points of the interconnecting ribbon 100 and the compressive stress on the surface of the cell string 200. The conductive layer 12 imparts conductivity to the interconnecting ribbon 100, ensuring good power generation efficiency of the photovoltaic module. The outer layer 13 is a low-temperature metal or low-temperature alloy. Low-temperature metals or low-temperature alloys have low melting points, are easy to weld, and can protect the conductive layer. After the conductive layer 12 is oxidized, its resistance increases and its conductivity decreases. Therefore, setting an outer layer 13 outside the conductive layer 12 can protect the conductive layer 12, reduce the contact between the conductive layer 12 and oxygen, and ensure the power generation efficiency of the cell string 200. The interconnecting ribbon 100 proposed in this application has high toughness and ductility, and maintains low stress even under large bending, which allows for smaller spacing between the cell strings 200, larger light-receiving area of ​​the cell strings 200, and improved module power generation efficiency. Meanwhile, the extrusion stress of the interconnecting solder strip 100 is relatively small, which makes it less likely for the cell string 200 to develop microcracks during lamination, thus improving the reliability of the module.

[0034] In one implementation, the core layer 11 has a rectangular cross-section (e.g., ...). Figure 1 As shown), circular (as shown) Figure 3At least one of the following: (as shown in Figure 4) or a triangle (as shown in Figure 4). The interconnecting ribbon 100 with a rectangular cross-section of the core layer 11 has a larger contact area with the battery string 200, making it less prone to misalignment during welding. Furthermore, due to the larger contact area with the battery string 200, there are no incomplete welds after welding, reducing contact resistance and improving conductivity. The interconnecting ribbon 100 with a circular cross-section of the core layer 11 has a higher light utilization rate compared to the interconnecting ribbon 100 with a rectangular cross-section of the core layer 11. The interconnecting ribbon 100 with a circular cross-section of the core layer 11 does not have orientation issues during welding; its cross-section remains circular regardless of how it is flipped. Moreover, the interconnecting ribbon 100 with a circular cross-section of the core layer 11 is easier to mass-produce than the interconnecting ribbon 100 with a rectangular or triangular cross-section of the core layer 11. The triangular cross-section interconnecting ribbon 100 of the core layer 11 inherits the advantage of low contact resistance of the rectangular cross-section interconnecting ribbon 100 of the core layer 11, and makes up for the disadvantage of low utilization of incident light by the rectangular cross-section interconnecting ribbon 100 of the core layer 11. The triangular cross-section interconnecting ribbon 100 of the core layer 11 can utilize almost all vertical and oblique incident light. At the same time, the triangular cross-section interconnecting ribbon 100 of the core layer 11 has a large contact area with the battery string 200, and is not prone to displacement during welding.

[0035] As one implementation method, such as Figure 5 As shown, the cross-sectional shapes of the conductive layer 12 and the outer layer 13 can be the same as or different from those of the core layer 11. Furthermore, the cross-sectional shapes of the conductive layer 12 and the outer layer 13 can also be different. In production, the shapes of the core layer 11, the conductive layer 12, and the outer layer 13 can be set according to actual needs. Furthermore, the cross-sections of different parts of an interconnecting ribbon 100 can be the same or different. For example, a part of the interconnecting ribbon 100 can be set to a triangular or circular cross-section for welding the front side of the first solar cell 21, which can reflect sunlight and improve module power. Another part of the interconnecting ribbon 100 can be set to a rectangular cross-section for welding the back side of the second solar cell 22, which can not only reduce the inter-cell spacing but also reduce the thickness of the encapsulating film on the back of the module, thus helping to reduce module costs. In production, the cross-sectional shapes of different parts of the interconnecting ribbon 100 can be set according to actual needs.

[0036] In one embodiment, when the cross-section of the core layer 11 is circular, the diameter of the conductive layer 12 is D, and the diameter of the core layer 11 is d; wherein, 1-δ 4 <0.95, δ=d / D. Although the conductivity of conductive layer 12 is good, its conductivity efficiency is still low because conductive layer 12 is too small. 1-δ 4 This is a key influencing factor in the moment of inertia of the circular cross-section interconnect weld strip 100. When the circular cross-section interconnect weld strip 100 satisfies 1-δ 4When the value is less than 0.95, under the same conductive layer 12 diameter D, the bending stress of the interconnecting solder strip 100 can be reduced by more than or equal to 5%, which can ensure that the bending stress on the interconnecting solder strip 100 is within an acceptable range, thus ensuring the service life of the interconnecting solder strip 100. At the same time, it can also ensure that the extrusion stress received by the battery cell is within an acceptable range, reducing the risk of microcracks.

[0037] In one implementation, when the cross-section of the core layer 11 is rectangular or triangular, the rectangular width or triangular base length of the conductive layer 12 is B, the rectangular height or triangular height of the conductive layer 12 is H, the rectangular width or triangular base length of the core layer 11 is b, and the rectangular height or triangular height of the core layer is h; wherein, 1-αβ 3 <0.95, α=b / B, β=h / H. Similarly, 1-αβ 3 This is a key influencing factor in the moment of inertia of the cross-section of the rectangular or triangular interconnect weld strip 100, when the cross-section of the interconnect weld strip 100 is rectangular or triangular and satisfies 1-αβ. 3 When the value is less than 0.95, under the same conductive layer 12 size, the bending stress of the interconnecting ribbon 100 can be reduced by more than or equal to 5%, which can ensure that the bending stress on the interconnecting ribbon 100 is within an acceptable range, thus ensuring the service life of the interconnecting ribbon 100. At the same time, it can also ensure that the extrusion stress on the battery cell is within an acceptable range, reducing the risk of microcracks.

[0038] In one implementation, the polymer material has a melting point greater than or equal to 140°C. As the core layer 11 of the interconnecting ribbon 100, the polymer material serves two purposes: firstly, it must provide the interconnecting ribbon 100 with sufficient strength to ensure the stability of its structure; secondly, it must ensure the interconnecting ribbon 100 has sufficient toughness to reduce bending and compressive stresses and protect the battery string 200. The polymer material's melting point of 140°C or higher ensures that the core layer 11 will not melt or soften during welding and battery string 200 operation, thus guaranteeing the stability of the interconnecting ribbon 100 structure and ensuring welding strength.

[0039] As one implementation method, the polymer material includes at least one of PP, PC, PET, or PA. PP is polypropylene, with a melting point typically between 165-173°C, ensuring the stability of the interconnect ribbon 100 structure during welding and operation. PP has good toughness and low bending stress during bending, preventing microcracks in the battery string 200. PP has a regular structure and high crystallinity, resulting in a higher melting point, greater heat resistance, and higher strength and rigidity, ensuring the stability of the interconnect ribbon 100. PC is polycarbonate, a high-molecular-weight polymer containing carbonate groups in its molecular chain, with a melting point typically between 220-230°C, ensuring the structural stability of the interconnect ribbon 100 during welding and operation. PC has advantages such as high impact strength, good fatigue resistance, good dimensional stability, and low creep, ensuring the long-term use and stability of the interconnect ribbon 100. Simultaneously, PC has high toughness, resulting in low extrusion stress during lamination, preventing microcracks in the battery string 200. PET is polyethylene terephthalate, a milky white or light yellow highly crystalline polymer with good strength, ensuring the stability of the interconnecting ribbon 100. PET's melting point is typically 220-230℃, ensuring the structural stability of the interconnecting ribbon 100 during welding and operation. It has good mechanical properties, with an impact strength 3-5 times that of other materials, and excellent physical and mechanical properties over a wide temperature range, allowing for long-term use in high-temperature environments. PA is polyamide, possessing good mechanical properties, high tensile strength, rigidity, and impact resistance, ensuring the strength of the interconnecting ribbon 100. PA's melting point is typically 220-263℃, ensuring the structural stability of the interconnecting ribbon 100 during welding and operation. Using at least one of PP, PC, PET, or PA for the core layer 11 ensures high strength and structural stability of the interconnecting ribbon 100. Using at least one of PP, PC, PET or PA can ensure that the interconnecting ribbon 100 has high toughness, so that the interconnecting ribbon 100 maintains low stress under large bending. At the same time, during lamination, the compressive stress between the interconnecting ribbon 100 and the battery string 200 is small, making it less likely for the battery string 200 to develop microcracks.

[0040] As one implementation method, the melting point of the cryogenic metal or cryogenic alloy is less than or equal to 180°C. The low melting point of cryogenic metals and cryogenic alloys results in a lower welding temperature, ensuring that the interconnecting strips 100 can be welded at the lamination temperature. Simultaneously, due to the low welding temperature, the deformation of the interconnecting strips 100 is minimal during welding, leading to a more stable structure; fewer harmful gas emissions result in a cleaner welding process; cryogenic welding machines consume less energy, saving energy; and cryogenic alloys produce smoother and more aesthetically pleasing welds. The melting point of the cryogenic metal or cryogenic alloy being less than or equal to 180°C ensures the structural stability of the interconnecting strips 100, facilitates welding, and results in smoother and more aesthetically pleasing welds.

[0041] As one implementation method, the cryogenic alloy includes at least one of tin-lead alloy, tin-bismuth-silver alloy, tin-indium alloy, or tin-lead-indium alloy. Tin-lead alloy has a low melting point, good fluidity, high solderability, fast welding speed, and high welding efficiency. Simultaneously, tin-lead alloy has low shrinkage, minimal deformation during welding, and structural stability. Tin-lead alloy has high corrosion resistance, which can better protect the conductive layer 12 and extend the service life of the interconnect solder strip 100. Lead-tin alloy has a dense crystal structure and a beautiful surface. Tin-bismuth-silver alloy has a high melting point, a narrow melting range, and a sensitive reaction; melting can be completed quickly after reaching the desired temperature. Simultaneously, tin-bismuth-silver alloy has high welding strength, can withstand certain atmospheric impacts without deformation, leakage, or perforation, ensuring the reliability of the interconnect solder strip 100. Tin-indium alloy and tin-lead-indium alloy have low melting points, good fluidity, fast welding speed, and high welding efficiency. Using cryogenic alloys such as tin-lead alloy, tin-bismuth-silver alloy, tin-indium alloy, or tin-lead-indium alloy for the outer layer 13 can ensure high corrosion resistance, effectively protecting the conductive layer 12 and preventing oxidation of the conductive layer 12. Meanwhile, low-temperature alloys such as tin-lead alloy, tin-bismuth-silver alloy, tin-indium alloy, or tin-lead-indium alloy are softer, have higher fluidity, and better weldability than other metals. They can make good contact with the battery string 200, and the stress generated during the welding process is very small, which can reduce the breakage rate of the battery string 200.

[0042] In one implementation, the conductive layer 12 comprises an alloy of one or at least two of copper, silver, or aluminum. Copper has low resistivity and good conductivity. Copper also has good ductility and low bending stress. Copper has high corrosion resistance and a long service life. Silver has low resistivity and good conductivity, and it can also increase the metallurgical bonding of the solder strip metal, resulting in high mechanical strength after welding. Aluminum is less expensive and significantly reduces weight. Using an alloy of one or at least two of copper, silver, or aluminum in the conductive layer 12 ensures that the conductive layer 12 has high conductivity while maintaining good ductility, giving the interconnect solder strip 100 good toughness.

[0043] In one implementation, the cross-sectional area of ​​the conductive layer 12 is S1, and the cross-sectional area of ​​the core layer 11 is S2, with the ratio of S1 to S2, S1 / S2, being greater than or equal to 1. If the area S1 of the conductive layer 12 is too small, the conductivity of the conductive layer 12 will decrease, thus affecting the power generation efficiency of the module. A ratio of S1 / S2 greater than or equal to 1 ensures the conductivity of the conductive layer 12.

[0044] This application also provides a method such as Figure 6 The photovoltaic module 300 shown includes, in sequence, a front substrate 31, a front encapsulating film 32, a cell layer 33, a rear encapsulating film 34, and a rear substrate 35. Figure 2As shown, the battery cell layer 23 includes at least one first battery cell 21, at least one second battery cell 22, and interconnecting solder strips 100, which are used to connect the first battery cell 21 and the second battery cell 22.

[0045] The present application will be further described below with reference to the embodiments, but the scope of protection of the present application is not limited to the embodiments.

[0046] Example 1

[0047] like Figure 1 As shown, an interconnecting solder strip 100 includes a core layer 11, a conductive layer 12, and an outer layer 13. The core layer 11 is made of PP, the conductive layer 12 is made of copper, and the outer layer 13 is a tin-bismuth-silver alloy with a melting point of 140°C.

[0048] The interconnecting strip 100 has a rectangular cross-sectional shape. The conductive layer 12 has a width B of 1 mm and a height H of 0.3 mm; the core layer 11 has a width b of 0.75 mm and a height h of 0.2 mm; the ratio of the cross-sectional area S1 of the conductive layer 12 to the cross-sectional area S2 of the core layer 11 is 1.00, 1-αβ 3 =0.78.

[0049] Example 2

[0050] like Figure 1 As shown, an interconnecting solder strip 100 includes a core layer 11, a conductive layer 12, and an outer layer 13. The core layer 11 is made of PP, the conductive layer 12 is made of copper, and the outer layer 13 is a tin-bismuth-silver alloy with a melting point of 140°C.

[0051] The interconnecting strip 100 has a rectangular cross-sectional shape. The conductive layer 12 has a width B of 1 mm and a height H of 0.5 mm; the core layer 11 has a width b of 0.5 mm and a height h of 0.4 mm; the ratio of the cross-sectional area S1 of the conductive layer 12 to the cross-sectional area S2 of the core layer 11 is 1.50, 1-αβ 3 =0.74.

[0052] Example 3

[0053] like Figure 1 As shown, an interconnecting solder strip 100 includes a core layer 11, a conductive layer 12, and an outer layer 13. The core layer 11 is made of PP, the conductive layer 12 is made of copper, and the outer layer 13 is a tin-bismuth-silver alloy with a melting point of 140°C.

[0054] The interconnecting strip 100 has a rectangular cross-sectional shape. The conductive layer 12 has a width B of 1 mm and a height H of 0.3 mm; the core layer 11 has a width b of 0.5 mm and a height h of 0.2 mm; the ratio of the cross-sectional area S1 of the conductive layer 12 to the cross-sectional area S2 of the core layer 11 is 2.00, 1-αβ 3 =0.85.

[0055] Example 4

[0056] like Figure 1 As shown, an interconnecting solder strip 100 includes a core layer 11, a conductive layer 12, and an outer layer 13. The core layer 11 is made of PP, the conductive layer 12 is made of aluminum, and the outer layer 13 is a tin-bismuth-silver alloy with a melting point of 140°C.

[0057] The interconnecting strip 100 has a rectangular cross-sectional shape. The conductive layer 12 has a width B of 1 mm and a height H of 0.3 mm; the core layer 11 has a width b of 0.75 mm and a height h of 0.2 mm; the ratio of the cross-sectional area S1 of the conductive layer 12 to the cross-sectional area S2 of the core layer 11 is 1.00, 1-αβ 3 =0.78.

[0058] Example 5

[0059] like Figure 1 As shown, an interconnecting solder strip 100 includes a core layer 11, a conductive layer 12, and an outer layer 13. The core layer 11 is made of PP, the conductive layer 12 is made of copper, and the outer layer 13 is a tin-bismuth alloy with a melting point of 130°C.

[0060] The interconnecting strip 100 has a rectangular cross-sectional shape. The conductive layer 12 has a width B of 1 mm and a height H of 0.3 mm; the core layer 11 has a width b of 0.75 mm and a height h of 0.2 mm; the ratio of the cross-sectional area S1 of the conductive layer 12 to the cross-sectional area S2 of the core layer 11 is 1.00, 1-αβ 3 =0.78.

[0061] Example 6

[0062] like Figure 1 As shown, an interconnecting solder strip 100 includes a core layer 11, a conductive layer 12, and an outer layer 13. The core layer 11 is PET, the conductive layer 12 is copper, and the outer layer 13 is a tin-bismuth-silver alloy with a melting point of 140°C.

[0063] The interconnecting strip 100 has a rectangular cross-sectional shape. The conductive layer 12 has a width B of 1 mm and a height H of 0.3 mm; the core layer 11 has a width b of 0.75 mm and a height h of 0.2 mm; the ratio of the cross-sectional area S1 of the conductive layer 12 to the cross-sectional area S2 of the core layer 11 is 1.00, 1-αβ 3 =0.78.

[0064] Example 7

[0065] like Figure 3 As shown, an interconnect solder strip 100 includes a core layer 11, a conductive layer 12, and an outer layer 13. The core layer 11 is a PA, the conductive layer 12 is copper, and the outer layer 13 is a tin-bismuth-silver alloy with a melting point of 140°C.

[0066] The interconnecting ribbon 100 has a circular cross-sectional shape. The diameter D of the conductive layer 12 is 0.3 mm, the diameter d of the core layer 11 is 0.21 mm, and the ratio of the cross-sectional area S1 of the conductive layer 12 to the cross-sectional area S2 of the core layer 11 is 1.04, 1-δ 4 =0.76.

[0067] Example 8

[0068] like Figure 3 As shown, an interconnect solder strip 100 includes a core layer 11, a conductive layer 12, and an outer layer 13. The core layer 11 is a PA, the conductive layer 12 is copper, and the outer layer 13 is a tin-bismuth-silver alloy with a melting point of 140°C.

[0069] The interconnecting ribbon 100 has a circular cross-sectional shape. The diameter D of the conductive layer 12 is 0.25 mm, the diameter d of the core layer 11 is 0.17 mm, and the ratio of the cross-sectional area S1 of the conductive layer 12 to the cross-sectional area S2 of the core layer 11 is 1.16, 1-δ 4 =0.789.

[0070] Example 9

[0071] like Figure 4 As shown, an interconnecting solder strip 100 includes a core layer 11, a conductive layer 12, and an outer layer 13. The core layer 11 is PET, the conductive layer 12 is aluminum, and the outer layer 13 is a tin-bismuth-silver alloy with a melting point of 140°C.

[0072] The interconnecting strip 100 has a triangular cross-sectional shape. The base length B of the conductive layer 12 is 0.8 mm, and the height H is 0.5 mm; the base length b of the core layer 11 is 0.5 mm, and the height h is 0.4 mm; the ratio of the cross-sectional area S1 of the conductive layer 12 to the cross-sectional area S2 of the core layer 11 is 1.00, 1-αβ 3 =0.68.

[0073] Example 10

[0074] like Figure 1 As shown, an interconnecting solder strip 100 includes a core layer 11, a conductive layer 12, and an outer layer 13. The core layer 11 is made of PP, the conductive layer 12 is made of copper, and the outer layer 13 is a tin-bismuth-silver alloy with a melting point of 140°C.

[0075] The interconnecting strip 100 has a rectangular cross-sectional shape. The conductive layer 12 has a width B of 1 mm and a height H of 0.3 mm; the core layer 11 has a width b of 0.79 mm and a height h of 0.21 mm; the ratio of the cross-sectional area S1 of the conductive layer 12 to the cross-sectional area S2 of the core layer 11 is 0.81, 1-αβ 3 =0.73.

[0076] Example 11

[0077] like Figure 1 As shown, an interconnecting solder strip 100 includes a core layer 11, a conductive layer 12, and an outer layer 13. The core layer 11 is made of PP, the conductive layer 12 is made of copper, and the outer layer 13 is a tin-bismuth-silver alloy with a melting point of 140°C.

[0078] The interconnecting strip 100 has a rectangular cross-sectional shape. The conductive layer 12 has a width B of 1 mm and a height H of 0.3 mm; the core layer 11 has a width b of 0.91 mm and a height h of 0.11 mm; the ratio of the cross-sectional area S1 of the conductive layer 12 to the cross-sectional area S2 of the core layer 11 is 2.00, 1-αβ 3 =0.955.

[0079] Example 12

[0080] like Figure 1 As shown, an interconnecting solder strip 100 includes a core layer 11, a conductive layer 12, and an outer layer 13. The core layer 11 is made of PE, the conductive layer 12 is made of copper, and the outer layer 13 is a tin-bismuth-silver alloy with a melting point of 140°C.

[0081] The interconnecting strip 100 has a rectangular cross-sectional shape. The conductive layer 12 has a width B of 1 mm and a height H of 0.3 mm; the core layer 11 has a width b of 0.75 mm and a height h of 0.2 mm; the ratio of the cross-sectional area S1 of the conductive layer 12 to the cross-sectional area S2 of the core layer 11 is 1.00, 1-αβ 3 =0.78.

[0082] Example 13

[0083] like Figure 1 As shown, an interconnect solder strip 100 includes a core layer 11, a conductive layer 12, and an outer layer 13. The core layer 11 is made of PP, the conductive layer 12 is made of copper, and the outer layer 13 is a tin-lead alloy with a melting point of 215°C.

[0084] The interconnecting strip 100 has a rectangular cross-sectional shape. The conductive layer 12 has a width B of 1 mm and a height H of 0.3 mm; the core layer 11 has a width b of 0.75 mm and a height h of 0.2 mm; the ratio of the cross-sectional area S1 of the conductive layer 12 to the cross-sectional area S2 of the core layer 11 is 1.00, 1-αβ 3 =0.78.

[0085] Example 14

[0086] An interconnecting solder strip 100 includes a core layer 11, a conductive layer 12, and an outer layer 13. The core layer 11 is made of PP, the conductive layer 12 is made of copper, and the outer layer 13 is a tin-bismuth-silver alloy with a melting point of 140°C.

[0087] The cross-sectional shape of one segment of the interconnecting solder strip 100 is as follows: Figure 1The rectangle shown has a conductive layer 12 with a width B of 1 mm and a height H of 0.3 mm; the core layer 11 has a width b of 0.75 mm and a height h of 0.2 mm. The ratio of the cross-sectional area S1 of the conductive layer 12 to the cross-sectional area S2 of the core layer 11 is 1.00, 1-αβ 3 =0.78; The cross-sectional shape of the remaining portion of the interconnecting solder strip 100 is as follows: Figure 3 The circle shown has a conductive layer 12 with a diameter D of 0.3 mm and a core layer 11 with a diameter d of 0.21 mm. The ratio of the cross-sectional area S1 of the conductive layer 12 to the cross-sectional area S2 of the core layer 11 is 1.04, 1-δ 4 =0.76. Among them, the circular cross-section portion of the interconnecting strip 100 accounts for 10% of the total length of the interconnecting strip 100, and the remaining portion is the rectangular cross-section portion.

[0088] Comparative Example 1

[0089] like Figure 7 As shown, an interconnect solder strip 100 includes a conductive layer 12 and an outer layer 13. The conductive layer 12 is copper, and the outer layer 13 is a tin-bismuth-silver alloy with a melting point of 140°C.

[0090] The conductive layer has a rectangular cross-sectional shape. The width of the conductive layer is 1 mm and the height is 0.3 mm.

[0091] Comparative Example 2

[0092] like Figure 8 As shown, an interconnect solder strip 100 includes a conductive layer 12, an outer layer 13, and an adhesive layer 14. The conductive layer 12 is copper, the outer layer 13 is a tin-bismuth-silver alloy with a melting point of 140°C, and the adhesive layer 14 is composed of organosilicon and copper conductive particles.

[0093] The conductive layer 12 has a circular cross-sectional shape. The outer layer 13 has a diameter D of 0.3 mm, the conductive layer has a diameter d of 0.21 mm, and the ratio of the cross-sectional area S1 of the outer layer 13 to the cross-sectional area S2 of the conductive layer is 1.04.

[0094] I. Performance Testing:

[0095] Performance tests were performed on the interconnect solder strip 100 and the photovoltaic module 300 including the interconnect solder strip 100 in the above embodiments and comparative examples.

[0096] Microcrack rate: Make a small component with a 4×4 cell pattern, test EL, and observe the microcracks at the edge of the cell.

[0097] Power test: Construct a small component with a 4×4 cell layout and test its power.

[0098] II. Performance Test Results:

[0099] The performance test results of the above embodiments and comparative examples of interconnect solder strip 100 and photovoltaic module 300 including interconnect solder strip 100 are shown in Table 1 below.

[0100] Table 1: Test Results

[0101]

[0102] As shown in Table 1, the modules in Examples 1-10 and Examples 12 and 13 had no microcracks. Example 11 had a few microcracks at the edge of the cell, caused by solder strip compression. Comparative Example 1 had some microcracks. In terms of power, Examples 1-9 and Examples 12 and 13 were all around 80W. In Example 10, the area ratio S of the conductive layer to the core layer was less than 1, resulting in a higher overall solder strip resistance and a 6% power reduction in the module. Examples 11, Comparative Examples 1, and Comparative Example 2 experienced approximately a 10% power reduction due to microcracks in the cell.

[0103] It should be understood that those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. An interconnecting solder strip, characterized in that, include: The core layer comprises a polymer material, the polymer material comprising at least one of PP, PC, PET or PA; A conductive layer is disposed on the outside of the core layer, and the conductive layer comprises one or an alloy of at least two of copper, silver or aluminum; An outer layer is disposed outside the conductive layer, and the outer layer includes at least one of a low-temperature metal or a low-temperature alloy, wherein the melting point of the low-temperature metal or the low-temperature alloy is less than or equal to 180°C.

2. The interconnecting solder strip according to claim 1, characterized in that: The cross-section of the core layer is at least one of a circle, a rectangle, or a triangle.

3. The interconnecting solder strip according to claim 2, characterized in that: When the cross-section of the core layer is circular, the diameter of the conductive layer is D, and the diameter of the core layer is d; where 1-δ 4 <0.95, δ=d / D.

4. The interconnecting solder strip according to claim 2, characterized in that: When the cross-section of the core layer is rectangular or triangular, the rectangular width or triangular base length of the conductive layer is B, the rectangular height or triangular height of the conductive layer is H, the rectangular width or triangular base length of the core layer is b, and the rectangular height or triangular height of the core layer is h. Among them, 1-ab 3 <0.95, α=b / B, β=h / H.

5. The interconnecting solder strip according to claim 1, characterized in that: The cryogenic alloy includes at least one of tin-lead alloy, tin-bismuth-silver alloy, tin-indium alloy, or tin-lead-indium alloy.

6. The interconnecting solder strip according to claim 1, characterized in that: The area of ​​the cross-section of the conductive layer is S1, the area of ​​the cross-section of the core layer is S2, and the ratio of S1 to S2, S1 / S2, is greater than or equal to 1.

7. A photovoltaic module, characterized in that, It includes at least one first battery cell, at least one second battery cell, and an interconnecting ribbon as described in any one of claims 1-6, wherein the interconnecting ribbon is used to connect the first battery cell and the second battery cell.

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