Solar cell string and solar cell module
By using linear conductive interconnects made of aluminum alloy, the problem of component failure caused by copper strip oxidation was solved, resulting in cost reduction and improved reliability.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-31
- Publication Date
- 2026-04-14
AI Technical Summary
In traditional back-contact solar cells, oxidation of the copper strip leads to module failure, increasing production costs and affecting module lifespan.
Linear conductive interconnects made of aluminum alloy with a dense aluminum oxide film spontaneously formed on their surface eliminate the need for solder layers, reducing production costs and improving reliability.
It effectively reduced production costs, lightened component weight, and improved component reliability and extended service life through the use of alumina film.
Smart Images
Figure CN224124506U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of solar cell technology, specifically to solar cell strings and solar cell modules. Background Technology
[0002] With the rapid development of photovoltaic technology, the efficiency of photovoltaic cells and modules has significantly improved, and new technologies are emerging one after another. Among them, back-contact module technology is regarded as one of the important development directions of the photovoltaic industry in the future due to its excellent conversion efficiency.
[0003] Traditional back-contact solar cells are connected via copper strips to form a cell string. Because the copper strips are encapsulated within the module's encapsulation material, which has extremely low air permeability, metallic copper easily oxidizes in low-oxygen environments, forming cuprous oxide. This oxide is incompatible with the weak acid ions contained in the photovoltaic module's encapsulation material, easily leading to module failure during long-term use. This problem not only affects the performance stability of the photovoltaic module but may also shorten its lifespan, thus negatively impacting the overall photovoltaic power generation efficiency.
[0004] Currently, the industry standard for addressing this issue is to coat the copper strip with a solder layer. This effectively prevents oxidation, thereby improving component reliability. However, since the core is made of copper, a relatively expensive metal, the solder layer, while providing some protection, also further increases production costs. Utility Model Content
[0005] The purpose of this invention is to provide a back-contact solar cell, a back-contact solar cell string, and a photovoltaic module to solve the problem of high production costs mentioned in the prior art.
[0006] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is as follows:
[0007] A solar cell string includes multiple back-contact solar cells and a linear conductive interconnect that connects adjacent back-contact solar cells in series. The back of each back-contact solar cell has a first electrode and a second electrode. The end of the second electrode near the first electrode is covered with an insulating layer, and the end of the first electrode near the second electrode is also covered with an insulating layer. The linear conductive interconnect includes an aluminum core. The first electrode is conductively connected to the linear conductive interconnect through a conductive connection layer, and the second electrode is conductively connected to the linear conductive interconnect through the conductive connection layer.
[0008] In some embodiments, the linear conductive interconnect includes an aluminum core and a solder layer covering the surface of the aluminum core, with the conductive connection layer being conductively connected to the solder layer.
[0009] In some embodiments, the solder layer continuously covers the surface of the linear conductive interconnect in the extension direction of the linear conductive interconnect, and the solder layer completely or partially surrounds the outer periphery of the linear conductive interconnect in the circumferential direction of the linear conductive interconnect.
[0010] In some embodiments, the first electrode includes a first bus electrode extending along a first direction and a first finger electrode extending along a second direction and connected to the first bus electrode. The second electrode includes a second bus electrode extending along the first direction and a second finger electrode extending along the second direction and connected to the second bus electrode. The first bus electrode and the second bus electrode are alternately arranged in the second direction, and the first finger electrode and the second finger electrode are alternately arranged in the first direction. The end of the first finger electrode connected to the first bus electrode is isolated from the second bus electrode adjacent to the first bus electrode, and the end of the second finger electrode connected to the second bus electrode is isolated from the first bus electrode adjacent to the second bus electrode. The first direction and the second direction intersect.
[0011] In some embodiments, the end of the second finger electrode near the first bus electrode is covered with an insulating layer, and the end of the first finger electrode near the second bus electrode is covered with an insulating layer.
[0012] In some implementations, the thickness of the solder layer is 0.2 μm to 20 μm.
[0013] In some implementations, the conductive connection layer includes solder paste or conductive adhesive.
[0014] In some implementations, the cross-sectional area of the aluminum core is 0.01 mm². 2 ~1mm 2 .
[0015] In some embodiments, the insulating layer is an acrylic resin adhesive, an epoxy resin adhesive, or a silicone sealant.
[0016] Solar cell module, including solar cell strings.
[0017] Due to the application of the above technical solution, the beneficial effects of this application compared with the prior art include:
[0018] The linear conductive interconnects of the back-contact solar cells are made of aluminum alloy. Since aluminum has a much lower density than copper, it is lighter for the same volume, effectively reducing production costs. Furthermore, the difference in conductivity between aluminum and copper is relatively small, further reducing costs and the overall weight of the module while ensuring good conductivity.
[0019] Furthermore, in low-oxygen environments, a dense alumina film spontaneously forms on the surface of linear conductive interconnects made of aluminum alloy. When the alumina reacts with acetic acid, a hydrolysis product in the encapsulation material, it generates water-insoluble aluminum acetate, which can absorb moisture, thereby improving product reliability. Therefore, it is no longer necessary to cover the linear conductive interconnects with a solder layer for protection, simplifying the manufacturing process and further reducing manufacturing costs and complexity. Attached Figure Description
[0020] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.
[0021] Figure 1 This is a schematic diagram of the back electrode of the back-contact solar cell in the solar cell string of this utility model.
[0022] Figure 2 This diagram illustrates a partial view of the solar cell string of this utility model;
[0023] Figure 3 This is a cross-sectional view of a back-contact solar cell in one embodiment of the present invention.
[0024] Figure 4 This is a cross-sectional view of a back-contact solar cell in one optional embodiment of the present invention.
[0025] Figure 5 This is a cross-sectional view of a back-contact solar cell in another optional embodiment of the present invention.
[0026] Figure 6 This is a cross-sectional view of a back-contact solar cell in another optional embodiment of the present invention.
[0027] Figure 7 This is a cross-sectional view of a back-contact solar cell in one embodiment of the present invention.
[0028] Explanation of reference numerals in the attached figures:
[0029] 1-Back contact solar cell; 2-First electrode; 3-Second electrode; 4-Linear conductive interconnect; 5-Solder layer; 6-Conductive connection layer; 7-Insulating layer; 21-First bus electrode; 22-First finger electrode; 31-Second bus electrode; 32-Second finger electrode; D1-First direction; D2-Second direction. Detailed Implementation
[0030] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.
[0031] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of this application described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.
[0032] In this application, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "middle," "vertical," "horizontal," "lateral," and "longitudinal" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for the purpose of better describing this application and its embodiments, and are not intended to limit the indicated device, element, or component to having a specific orientation, or to be constructed and operated in a specific orientation.
[0033] Furthermore, in addition to indicating location or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in some cases to indicate a certain dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.
[0034] Furthermore, the terms "installation," "setup," "equipped with," "connection," "linking," and "socketing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral structure; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium, or an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.
[0035] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.
[0036] Please combine Figure 1 and Figure 2 The solar cell string includes multiple back-contact solar cells 1 and a linear conductive interconnect 4 that connects adjacent back-contact solar cells 1 in series. The back of the back-contact solar cells 1 is provided with a first electrode 2 and a second electrode 3. The end of the second electrode 3 near the first electrode 2 is covered with an insulating layer 7, and the end of the first electrode 2 near the second electrode 3 is covered with an insulating layer 7. The linear conductive interconnect 4 includes an aluminum core. The first electrode 2 has a conductive connection layer 6, which is conductively connected to the linear conductive interconnect 4. The first electrode 2 is conductively connected to the linear conductive interconnect 4 through the conductive connection layer 6, and the second electrode 3 is conductively connected to the linear conductive interconnect 4 through the conductive connection layer 6.
[0037] In some implementation methods, please refer to Figure 1 The first electrode 2 includes a first bus electrode 21 extending along a first direction D1 and a first finger electrode 22 extending along a second direction D2 and connected to the first bus electrode 21. The second electrode 3 includes a second bus electrode 31 extending along the first direction D1 and a second finger electrode 32 extending along the second direction D2 and connected to the second bus electrode 31. The first bus electrode 21 and the second bus electrode 31 are alternately arranged in the second direction D2, and the first finger electrode 22 and the second finger electrode 32 are alternately arranged in the first direction D1. The end of the first finger electrode 22 connected to the first bus electrode 21 is isolated from the adjacent second bus electrode 31, and the end of the second finger electrode 32 connected to the second bus electrode 31 is isolated from the adjacent first bus electrode 21. The first direction D1 and the second direction D2 intersect. The first electrode 2 can be a positive electrode, and the second electrode 3 can be a negative electrode. Alternatively, the first electrode 2 can be a negative electrode, and the second electrode 3 can be a positive electrode.
[0038] In some implementation methods, please refer to Figure 2 The end of the second finger electrode 32 near the first bus electrode 21 is covered by the insulating layer 7, and the end of the first finger electrode 22 near the second bus electrode 31 is covered by the insulating layer 7.
[0039] The aluminum core of the linear conductive interconnect 4 is made of aluminum alloy. Since the density of aluminum is much lower than that of copper, aluminum is lighter in weight for the same volume, which effectively reduces production costs. In addition, the difference in conductivity between aluminum and copper is relatively small, which further reduces costs and lightens the overall weight of the component while ensuring good conductivity.
[0040] Furthermore, in a low-oxygen environment, a dense aluminum oxide film spontaneously forms on the surface of the linear conductive interconnect 4 made of aluminum alloy. When the aluminum oxide reacts with acetic acid, a hydrolysis product in the encapsulation material, it generates aluminum acetate, which is insoluble in water and can absorb moisture, thereby improving product reliability. Therefore, it is no longer necessary to cover the linear conductive interconnect 4 with a solder layer 5 for protection, thus simplifying the manufacturing process and further reducing manufacturing costs and complexity.
[0041] In some embodiments, the aluminum alloy is high-purity aluminum. Specifically, the linear conductive interconnect 4 can be an aluminum strip, aluminum bar, or aluminum foil; this application does not specifically limit the shape of the linear conductive interconnect.
[0042] In some embodiments, the cross-sectional area of the aluminum core is 0.01 mm². 2 ~1mm 2 Specifically, it can be 0.05mm. 2 0.08mm 2 This application does not impose specific limitations on this.
[0043] The cross-section of the aluminum core can be rectangular, square, circular, elliptical, triangular, regular hexagonal, or other shapes.
[0044] like Figure 3 As shown, the linear conductive interconnect 4 can be an aluminum core, which is directly connected to the first electrode 2 or the second electrode 3 through the conductive connection layer 2.
[0045] like Figure 4-6 The aluminum core can also be coated with a solder layer 5. Specifically, the linear conductive interconnect 4 includes an aluminum core and a solder layer 5 coated on the surface of the aluminum core. The conductive connection layer 6 is conductively connected to the solder layer 5. The solder layer 5 continuously covers the surface of the linear conductive interconnect 4 in the extending direction of the linear conductive interconnect 4. The solder layer 5 completely or partially surrounds the outer periphery of the linear conductive interconnect 4 in the circumferential direction of the linear conductive interconnect 4.
[0046] Please see Figures 4 to 6 This embodiment provides a solar cell string, wherein a solder layer 5 is provided at least at the position where the linear conductive interconnect 4 is connected to the first electrode 2 and the second electrode 2. Specifically, the solder layer 5 has a thickness of 0.2μm to 20μm and a melting point of 70℃ to 190℃.
[0047] Please see Figure 4 In an optional embodiment, a solder layer 5 is provided at the position where the linear conductive interconnect 4 is connected to the first electrode 2.
[0048] Please see Figure 5In another optional embodiment, a solder layer 5 is provided at the position where the linear conductive interconnect 4 is connected to the first electrode 2 and on its opposite side.
[0049] Please see Figure 6 In another alternative embodiment, the entire outer periphery of the linear conductive interconnect 4 is provided with a solder layer 5.
[0050] Please see Figure 7 This embodiment provides a solar cell string, wherein the solder layer 5 is electrically connected to the first electrode 2 via a conductive connection layer 6. For example, the conductive connection layer 6 includes solder paste or conductive adhesive.
[0051] This embodiment provides a photovoltaic module, including the aforementioned solar cell string.
[0052] Finally, it should be noted that the above are merely preferred embodiments of this application and are not intended to limit this application. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. 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 solar cell string, characterized in that, The device includes multiple back-contact solar cells and a linear conductive interconnect that connects adjacent back-contact solar cells in series. The back of each back-contact solar cell has a first electrode and a second electrode. The end of the second electrode near the first electrode is covered with an insulating layer, and the end of the first electrode near the second electrode is also covered with an insulating layer. The linear conductive interconnect includes an aluminum core. The first electrode is conductively connected to the linear conductive interconnect through a conductive connection layer, and the second electrode is conductively connected to the linear conductive interconnect through the conductive connection layer.
2. The solar cell string as described in claim 1, characterized in that, The linear conductive interconnect includes an aluminum core and a solder layer covering the surface of the aluminum core, and the conductive connection layer is conductively connected to the solder layer.
3. The solar cell string as described in claim 2, characterized in that, The solder layer continuously covers the surface of the linear conductive interconnect in the extending direction of the linear conductive interconnect, and the solder layer completely or partially surrounds the outer periphery of the linear conductive interconnect in the circumferential direction of the linear conductive interconnect.
4. The solar cell string as described in claim 1, characterized in that, The first electrode includes a first bus electrode extending along a first direction and a first finger electrode extending along a second direction and connected to the first bus electrode. The second electrode includes a second bus electrode extending along a first direction and a second finger electrode extending along a second direction and connected to the second bus electrode. The first bus electrode and the second bus electrode are alternately arranged in the second direction, and the first finger electrode and the second finger electrode are alternately arranged in the first direction. The end of the first finger electrode connected to the first bus electrode is isolated from the second bus electrode adjacent to the first bus electrode. The end of the second finger electrode connected to the second bus electrode is isolated from the first bus electrode adjacent to the second bus electrode. The first direction intersects with the second direction.
5. The solar cell string as described in claim 4, characterized in that, The end of the second finger electrode near the first bus electrode is covered with an insulating layer, and the end of the first finger electrode near the second bus electrode is covered with an insulating layer.
6. The solar cell string as described in claim 2, characterized in that, The thickness of the solder layer is 0.2μm to 20μm.
7. The solar cell string as described in claim 2, characterized in that, The conductive connection layer includes solder paste or conductive adhesive.
8. The solar cell string as described in claim 1, characterized in that, The cross-sectional area of the aluminum core is 0.01 mm². 2 ~1mm 2 .
9. The solar cell string as described in claim 1, characterized in that, The insulating layer is made of acrylic resin, epoxy resin, or silicone.
10. A solar cell module, characterized in that, It includes at least one solar cell string as described in any one of claims 1 to 9.