Junction box for solar power generation modules

Abstract

We provide junction boxes for solar power generation modules. [Solution] The invention includes a cable 1, a pressing plate 8, and an adhesive plate 7. The pressing plate 8 and the adhesive plate 7 are stacked in parallel and together form the housing of a junction box. One end of the cable 1 passes sequentially through the pressing plate 8 and the adhesive plate 7. The outer casing of the cable 1 is fixedly connected to the pressing plate 8 and the adhesive plate 7. A metal member 2 is provided inside the outer casing, leaving a gap between the pressing plate 8 and the adhesive plate 7. This gap becomes a flexible compressible region 6, and a conductive curable gel is filled into the flexible compressible region 6. Multiple vias 5 are provided on the adhesive plate 7. One end of each via 5 communicates with the flexible compressible region 6, and the other end is in close contact with the adhesive surface of the photovoltaic power generation module 9. This invention enables rapid circuit communication and adhesion with the photovoltaic power generation module, provides good water-oxygen barrier properties and insulation, and improves the production efficiency and long-term weather resistance of the photovoltaic power generation module.

Description

[Technical Field]

[0001] [Cross-reference of related applications] This disclosure claims priority to a Chinese patent application filed with the China National Intellectual Property Office on 10 February 2025, application number CN202510145214.6, titled "Junction Box for Photovoltaic Modules," the entire contents of which are incorporated herein by reference.

[0002] This application relates to the field of the solar power generation industry, and more particularly to junction boxes for solar power generation modules. [Background technology]

[0003] The junction box for solar power modules is a critical component connecting the solar power module to the power system, and its performance directly impacts the power generation efficiency and long-term stability of the solar power module. Conventional junction boxes are connected to the positive and negative bus ends of the solar power module by welding, and are fixed to the back of the solar power module with water barrier adhesive, silicone resin, or double-sided foam tape, with epoxy resin or silicone resin filled as a potting adhesive inside the junction box. The above conventional processes and materials not only reduce the production efficiency of the module, but also make it difficult to prevent water vapor and oxygen from entering the module through holes on the back of the module during the adhesive curing process, thus degrading the module's performance. Furthermore, this type of material has low water and oxygen barrier properties and cannot guarantee the long-term weather resistance of solar power modules, which are sensitive to water and oxygen.

[0004] Therefore, there is a need to provide a junction box that enables rapid circuit connection and bonding with photovoltaic modules, while also possessing good water-oxygen barrier properties and insulation, thereby improving the production efficiency and long-term weather resistance of photovoltaic modules. [Overview of the project] [Problems that the invention aims to solve]

[0005] The present invention aims to provide a junction box that overcomes the shortcomings of the prior art described above, enabling rapid circuit connection and adhesion with photovoltaic power generation modules, while also possessing good water-oxygen barrier properties and insulation, thereby improving the production efficiency and long-term weather resistance of photovoltaic power generation modules. [Means for solving the problem]

[0006] To achieve the above objective, this application provides the following technical solutions.

[0007] A junction box for solar power generation modules, It includes a cable, a pressing plate, and an adhesive plate, The pressing plate and the adhesive plate are stacked in parallel. One end of the cable passes through the pressing plate and the adhesive plate in sequence, the outer casing of the cable is fixed and connected to the pressing plate and the adhesive plate, and a metal member is provided inside the outer casing. A gap remains between the pressing plate and the adhesive plate, and this gap becomes a flexible and compressible region, into which a conductive curable gel is filled. Multiple vias are provided on the adhesive plate, with one end of each via communicating with a flexible and compressible region and the other end in close contact with the adhesive surface of the solar power generation module.

[0008] Furthermore, the flexible and compressible region is filled with multiple first-order brittle capsules and multiple second-order brittle capsules.

[0009] Furthermore, the components of the first and second brittle capsules include one or more of the following: polystyrene, polyurethane, polylactic acid, polymethyl methacrylate, and silica gel.

[0010] Furthermore, the first brittle capsule is filled with a conductive metal polymer composite gel, and the second brittle capsule is filled with a modified graft polymer.

[0011] Furthermore, the conductive metal polymer composite gel includes a metal nanocomposite material in which an acrylic acid copolymer is grafted onto n-butyl acrylate.

[0012] Furthermore, the modified graft polymers include polystyrene-grafted polyisobutylene, polydimethylsiloxane-grafted acrylic acid, α-pinenyl methacrylate-grafted butyl acrylate, methacryloyloxypropyl silsesquioxane-grafted methacrylate-butyl acrylate 2-(2-ethoxyethoxy)ethyl acrylate, and polyurethane-acrylic acid block copolymers, each with different main chain lengths and side chain densities.

[0013] Furthermore, the height of the first brittle capsule is greater than the height of the second brittle capsule.

[0014] Furthermore, the height of the first brittle capsule is equal to the height of the second brittle capsule.

[0015] Furthermore, the pressing plate includes multiple independent pressing regions for pressing the first brittle capsule and the second brittle capsule, respectively.

[0016] Furthermore, the pressing plate and adhesive plate are manufactured using flame-retardant polymers. [Effects of the Invention]

[0017] The technical effects and advantages of this invention are as follows:

[0018] 1. The novel junction box for photovoltaic modules of this invention enables rapid circuit connection and adhesion with photovoltaic modules, and also provides good water-oxygen barrier properties and insulation, thereby improving the production efficiency and long-term weather resistance of photovoltaic modules.

[0019] 2. In the junction box of the present application, the silicone resin of the conventional junction box is avoided from having the drawback of curing slowly through heating and humidification (usually, the complete curing time is as long as 24 h), and the drawback that a large number of production line arrangements are required for welding the junction box and the welding process is complicated is avoided. At the same time, instant circuit connection is realized by applying pressure. The acrylic composite material has a short curing time, instantaneously cross-links after applying normal pressure, and greatly shortens the time required for installing the junction box.

[0020] 3. The present application provides a flexible compressible region, a first brittle capsule, and a second brittle capsule in the junction box. By filling the first brittle capsule and the second brittle capsule with a conductive metal polymer composite gel and a modified graft polymer respectively, when pressure is applied, the first brittle capsule and the second brittle capsule rupture sequentially. The conductive metal polymer composite gel is firmly bonded to the positive and negative electrodes of the bus ends of the photovoltaic module, thereby realizing circuit communication, quickly cross-linking and curing the graft polymer, and fixing the junction box on the surface of the photovoltaic backplane. The operation is simple and fast, the production efficiency of the photovoltaic module is greatly improved. Furthermore, after self-cross-linking, the graft polymer has a strong hydrogen barrier property and is much superior to commercially available photovoltaic package products.

[0021] Other features and advantages of the present application will be described in the following description, and will become partially apparent from the specification or will be understood through the implementation of the present application. The objectives and other advantages of the present application can be achieved and obtained by the configurations shown in the specification, claims and drawings.

Brief Description of the Drawings

[0022] To more clearly illustrate the technical solutions in the embodiments of the present disclosure or the related art, the drawings required for the description of the embodiments or the related art will be briefly described below. The drawings in the following description are some embodiments of the present disclosure, and it is obvious to those skilled in the art that other drawings can be obtained based on these drawings without creative efforts. [Figure 1] It is a schematic diagram of Structure A of the junction box for a photovoltaic module of the present application. [Figure 2] It is a schematic diagram of Structure A of the junction box for a photovoltaic module after the first brittle capsule ruptures. [Figure 3] It is a schematic diagram of Structure A of the junction box for a photovoltaic module after the second brittle capsule ruptures. [Figure 4] It is a schematic diagram of Structure A of the junction box for a photovoltaic module after crosslinking and curing. [Figure 5] It is a schematic diagram of Structure B of the junction box for a photovoltaic module of the present application.

Mode for Carrying Out the Invention

[0023] Hereinafter, referring to the drawings in the embodiments of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described. It is clear that the described embodiments are only a part of the embodiments of the present application, not all of the embodiments. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative efforts belong to the protection scope of the present application.

[0024] As shown in Figure 1, the present invention provides a junction box for a photovoltaic module, comprising a cable 1, a pressing plate 8, and an adhesive plate 7. The pressing plate 8 and the adhesive plate 7 are stacked in parallel, and the adhesive plate 7 is in close contact with the back plate of the photovoltaic module 9 to fix the junction box for the photovoltaic module to the surface of the photovoltaic module 9. The pressing plate 8 is for applying pressure to the adhesive plate 7. Together, the pressing plate 8 and the adhesive plate 7 constitute the housing of the junction box, leaving a gap between the pressing plate 8 and the adhesive plate 7, which becomes a flexible compressible region 6. Multiple vias 5 are provided on the adhesive plate 7, with one end of each via 5 communicating with the flexible compressible region 6 and the other end in close contact with the adhesive surface of the back plate of the photovoltaic module 9. One end of cable 1 sequentially passes through a pressing plate 8 and an adhesive plate 7, and the outer casing of cable 1 is fixedly connected to the pressing plate 8 and the adhesive plate 7. A metal member 2 is provided inside the outer casing, and the metal member 2 is used for circuit connection of the photovoltaic power generation module 9. A plurality of first brittle capsules 3 and a plurality of second brittle capsules 4 are filled within a flexible compressible region 6. The components of the first brittle capsules 3 and the second brittle capsules 4 include one or more of polystyrene, polyurethane, polylactic acid, polymethyl methacrylate, and silica gel. A conductive metal polymer composite gel is filled inside the first brittle capsules 3, and a modified graft polymer is filled inside the second brittle capsules 4. The height of the first brittle capsules 3 is greater than the height of the second brittle capsules 4. As shown in Figure 2, when the pressing plate 8 is pressed, pressure is also applied to the flexible compressible region 6. At this time, the first brittle capsule 3, being taller, is subjected to the force first and ruptures, releasing the conductive metal polymer composite gel. The conductive metal polymer composite gel passes through the via 5 and fills the gap between the adhesive plate 7 and the adhesive surface of the photovoltaic module 9. At this time, the flexible compressible region 6 still contains the second brittle capsule 4, which has not yet ruptured. As shown in Figure 3, a second large external force is applied to the pressing plate 8, causing the second brittle capsule 4 to rupture and allowing the modified graft polymer to flow into the gap between the adhesive plate 7 and the adhesive surface of the photovoltaic module 9.As shown in Figure 4, the conductive metal polymer composite gel and the modified graft polymer undergo a self-crosslinking reaction in the gap between the adhesive plate 7 and the adhesive surface of the photovoltaic module 9, and harden, completing the attachment of the junction box to the photovoltaic module 9.

[0025] In some embodiments of the present application, the conductive metal polymer composite gel comprises a metal nanocomposite material grafted with n-butyl acrylate and / or acrylic acid copolymer. The modified graft polymers include polystyrene-grafted polyisobutylene, polydimethylsiloxane-grafted acrylic acid, α-pinenyl methacrylate-grafted butyl acrylate, methacryloyloxypropyl silsesquioxane-grafted methacrylate-butyl acrylate 2-(2-ethoxyethoxy)ethyl acrylate, and polyurethane-acrylic acid block copolymers, with different main chain lengths and side chain densities. The pressing plates and adhesive plates are manufactured using flame-retardant polymers.

[0026] In some embodiments of the present invention, as shown in Figure 5, the height of the first brittle capsule 3 is equal to the height of the second brittle capsule 4, and the pressing plate 8 includes a plurality of independent pressing regions for pressing the first brittle capsule 3 and the second brittle capsule 4, respectively, and by pressing the corresponding pressing regions of the first brittle capsule 3 and the second brittle capsule 4, the first brittle capsule 3 and the second brittle capsule 4 burst sequentially.

[0027] The operating principle of the junction box for solar power generation modules of this invention is as follows.

[0028] The junction box housing is constructed using a flame-retardant polymer pressing plate 8 and an adhesive plate 7. A flexible compressible region 6 is formed by leaving a gap between the pressing plate 8 and the adhesive plate 7. A first brittle capsule 3 and a second brittle capsule 4 are embedded inside the flexible compressible region 6, and multiple vias 5 are provided in the adhesive plate 7 for the outflow of the conductive metal polymer composite gel and the modified graft polymer gel. One end of the cable 1 is passed through the pressing plate 8 and the adhesive plate 7 in sequence, and the outer casing of the cable 1 is fixed and connected to the pressing plate 8 and the adhesive plate 7. The metal member 2 inside the cable 1 is used to make a circuit connection with the photovoltaic power generation module 9.

[0029] When connecting the junction box and the photovoltaic module 9, the junction box is positioned on the adhesive surface of the backplate of the photovoltaic module 9, aligning the positive and negative electrode bus ends. When the first pressure is applied to the pressure plate 8 to compress the flexible compressible region 6, the first brittle capsule 3 ruptures, releasing the conductive metal polymer composite gel. This conductive metal polymer composite gel fills the gap between the junction box and the backplate of the photovoltaic module 9 via the vias 7. At this point, the flexible compressible region 6 still contains the unruptured second brittle capsule 4. When the second pressure is applied to the pressure plate 8, the solvent containing the modified graft polymer gel solute also flows into the gap between the junction box and the backplate of the photovoltaic module 9. At this point, the conductive metal polymer composite gel and the modified graft polymer gel undergo a self-crosslinking reaction in the gap between the junction box and the backplate of the photovoltaic module 9, hardening and completing the attachment of the junction box to the photovoltaic module 9.

[0030] To better illustrate this solution, the following embodiments are provided. Example 1

[0031] Polystyrene-grafted polyisobutylene was selected as the modified graft polymer, and the conductive metal polymer composite gel was composed of a silver nanocomposite material in which an acrylic acid copolymer was grafted onto n-butyl acrylate. Based on this configuration, a junction box was assembled and subjected to comprehensive testing on the photovoltaic module 9. During the testing process, pressure was applied to trigger compression of the flexible compressible region 9 and rupture of the brittle capsule, after which a pressure of 30N was continuously applied to promote the self-crosslinking reaction between the conductive metal polymer composite gel and the graft polymer gel.

[0032] After tightly connecting and curing the junction box and the solar power generation module 9, the resistance value of the circuit was measured using a 4-probe tester. The resistance value was 0.3Ω, which is equivalent to the circuit conductivity (0.25Ω) in the case of the conventional welding method, confirming the reliability of the circuit connectivity of the new junction box.

[0033] The water-oxygen barrier properties of the new junction box were evaluated, and WVTR (water vapor transmission rate) and OTR (oxygen transmission rate) tests were performed. The WVTRs of three samples of the new junction box were 0.5, 0.4, and 0.8 g / m², respectively. 2 • Day and OTR were 2.3, 4.6, and 5.1 x 10, respectively. -3 cc / m 2 Although the result was d, the WVTR values ​​of the three conventional junction box samples were 2.4, 2.5, and 3.1 g / m², respectively. 2 • Day and OTR were 20.8, 22.1, and 21.7 x 10, respectively. -3 cc / m 2 The result was d. This comparison clearly demonstrated the significant advantage of the new junction box in terms of water barrier and oxygen barrier properties. Example 2

[0034] Except for using polydimethylsiloxane grafted acrylic acid as the modified graft polymer material, other materials were the same as those in Example 1, and the same test procedures as in Example 1 were carried out. As a result of the test, it was shown that the new junction box of this example was superior to the junction box of Example 1 in terms of hydrogen oxygen barrier properties.

[0035] Furthermore, the efficiency of the module connected by the junction box was tested. Taking a 30*40cm 2 module as an example, the module efficiency of 3 samples of the junction box of this example was between 15.42% and 16.41% as shown in Table 1. On the other hand, the module efficiency of 3 samples of the conventional junction box was between 15.78% and 16.63% as shown in Table 2. This result further confirmed the effectiveness of maintaining the module efficiency of the new junction box.

[0036] Table 1 Efficiency of the 30*40cm 2 module connected by the junction box of Example 2 JPEG2026137632000002.jpg31132 <S

[0037] Table 2 Efficiency of the 30*40cm 2 module connected by the conventional junction box JPEG2026137632000003.jpg~31132

[0038] From the above, the new junction box of the present application has not only succeeded in solving many problems existing in the conventional junction box, such as low production efficiency and low hydrogen oxygen barrier properties, but is also excellent in maintaining the module efficiency. Therefore, the new junction box of the present application has great potential in the future and market.

[0039] The above are merely preferred embodiments of the present application and do not limit it. While the present application has been described in detail with reference to the above embodiments, those skilled in the art can modify the technical solutions described in each of the above embodiments or replace some of their technical features with equivalents. Any modifications, equivalent replacements, improvements, etc., made within the spirit and principles of the present application should be included within the scope of protection.

Claims

1. It includes a cable (1), a pressing plate (8), and an adhesive plate (7), The pressing plate (8) and the adhesive plate (7) are stacked in parallel. One end of the cable (1) passes through the pressing plate (8) and the adhesive plate (7) in sequence, the outer casing of the cable (1) is fixedly connected to the pressing plate (8) and the adhesive plate (7), and a metal member (2) is provided inside the outer casing. A gap remains between the pressing plate (8) and the adhesive plate (7), and this gap becomes a flexible compressible region (6), and a conductive curable gel is filled into the flexible compressible region (6). A junction box for a solar power generation module, characterized in that a plurality of vias (5) are provided on the adhesive plate (7), one end of each via (5) communicates with a flexible compressible region (6), and the other end is in close contact with the adhesive surface of a solar power generation module (9).

2. The junction box for a photovoltaic module according to claim 1, wherein a plurality of first brittle capsules (3) and a plurality of second brittle capsules (4) are filled within the flexible compressible region (6).

3. The junction box for a solar power generation module according to claim 2, wherein the components of the first brittle capsule (3) and the second brittle capsule (4) include one or more of polystyrene, polyurethane, polylactic acid, polymethyl methacrylate, and silica gel.

4. The junction box for a photovoltaic module according to claim 2, wherein a conductive metal polymer composite gel is filled inside the first brittle capsule (3), and a modified graft polymer is filled inside the second brittle capsule (4).

5. The junction box for a solar power generation module according to claim 4, wherein the conductive metal polymer composite gel comprises a metal nanocomposite material obtained by grafting an acrylic acid copolymer onto n-butyl acrylate.

6. The junction box for a solar power generation module according to claim 5, wherein the modified graft polymer includes polystyrene-grafted polyisobutylene, polydimethylsiloxane-grafted acrylic acid, α-pinenyl methacrylate-grafted butyl acrylate, methacryloyloxypropyl silsesquioxane-grafted methacrylate-butyl acrylate 2-(2-ethoxyethoxy)ethyl acrylate, and polyurethane-acrylic acid block copolymer, with different main chain lengths and side chain densities.

7. The junction box for a solar power generation module according to claim 2, wherein the height of the first brittle capsule (3) is greater than the height of the second brittle capsule (4).

8. The junction box for a solar power generation module according to claim 2, wherein the height of the first brittle capsule (3) is equal to the height of the second brittle capsule (4).

9. The junction box for a photovoltaic module according to claim 8, wherein the pressing plate (8) includes a plurality of independent pressing regions for pressing the first brittle capsule (3) and the second brittle capsule (4), respectively.

10. The junction box for a solar power generation module according to claim 1, wherein the pressing plate and the adhesive plate (7) are manufactured using a flame-retardant polymer.

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