A photovoltaic module junction box

Abstract

The application belongs to the field of photovoltaic industry, and discloses a kind of photovoltaic module junction box, including cable, extrusion plate and adhesive plate;Extrusion plate and adhesive plate are stacked in parallel;One end of cable passes through extrusion plate and adhesive plate in turn, the shell of cable is fixedly connected with extrusion plate and adhesive plate, metal piece is arranged in shell, gap is left between extrusion plate and adhesive plate, gap constitutes flexible compressible area, flexible compressible area is filled with conductive, solidifiable gel, a plurality of through holes are arranged on adhesive plate, one end of through hole is communicated with flexible compressible area, and the other end is attached to the adhesive surface of photovoltaic module.The novel photovoltaic module junction box of the application can quickly realize circuit communication and adhesion with photovoltaic module, and has good water and oxygen barrier and insulation performance, improves the production efficiency and long-term weather resistance of photovoltaic module.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of photovoltaic industry, and particularly relates to a junction box of a photovoltaic module. BACKGROUND

[0002] The junction box of the photovoltaic module is an important component for connecting the photovoltaic module and the power system, and its performance directly affects the power generation efficiency and long-term stability of the photovoltaic module. The traditional junction box is connected with the positive and negative busbars of the photovoltaic module by welding, and is fixed on the back of the photovoltaic module by water-blocking silicone, silicone resin or double-sided foam tape. Epoxy resin or silicone resin is used as the potting adhesive to fill the inside of the junction box. The above-mentioned traditional process and materials not only reduce the production efficiency of the module, but also cannot ensure that water vapor, oxygen and the like do not enter the inside of the module through the holes on the back of the module during the curing process of the adhesive, thereby causing the performance of the module to decrease. Moreover, the water and oxygen blocking performance of such materials is poor, and the long-term weather resistance of the photovoltaic module sensitive to water and oxygen cannot be guaranteed.

[0003] Therefore, it is necessary to provide a junction box which can quickly realize the electrical circuit communication and bonding with the photovoltaic module, has good water and oxygen blocking and insulation performance, and improves the production efficiency and long-term weather resistance of the photovoltaic module. SUMMARY

[0004] In order to overcome the defects of the prior art, the purpose of the present application is to provide a junction box which can quickly realize the electrical circuit communication and bonding with the photovoltaic module, has good water and oxygen blocking and insulation performance, and improves the production efficiency and long-term weather resistance of the photovoltaic module.

[0005] To achieve the above-mentioned purpose, the present application provides the following technical solutions:

[0006] A junction box of a photovoltaic module, comprising a cable, an extrusion plate and a bonding plate;

[0007] The extrusion plate and the bonding plate are stacked in parallel;

[0008] One end of the cable passes through the extrusion plate and the bonding plate in sequence, the shell of the cable is fixedly connected with the extrusion plate and the bonding plate, and a metal piece is arranged in the shell;

[0009] A gap is left between the extrusion plate and the bonding plate, the gap constitutes a flexible compressible area, and the flexible compressible area is filled with a conductive and curable gel;

[0010] A plurality of through holes are arranged on the bonding plate, one end of each through hole is communicated with the flexible compressible area, and the other end of each through hole is attached to the bonding surface of the photovoltaic module.

[0011] Further, a plurality of first brittle capsules and a plurality of second brittle capsules are filled in the flexible compressible area.

[0012] Further, the components of the first and second brittle capsules include one or more of polystyrene, polyurethane, polylactic acid, polymethyl methacrylate, and silica gel.

[0013] Further, the first brittle capsule is filled with an electrically conductive metal polymer composite gel, and the second brittle capsule is filled with a modified graft polymer.

[0014] Further, the electrically conductive metal polymer composite gel includes a metal nanocomposite grafted with a copolymer of n-butyl acrylate and acrylic acid.

[0015] Further, the modified graft polymer includes polystyrene grafted polyisobutylene, polydimethylsiloxane grafted acrylic acid, alpha-pinene methacrylate grafted butyl acrylate, methylacryloyloxypropylsilsesquioxane grafted methyl methacrylate-butyl acrylate-2-(2-ethoxyethoxy)ethyl acrylate, polyurethane-acrylic block copolymer with different backbone chain lengths and side chain densities.

[0016] Further, the height of the first brittle capsule is greater than the height of the second brittle capsule.

[0017] Further, the height of the first brittle capsule is equal to the height of the second brittle capsule.

[0018] Further, the extrusion plate includes a plurality of independent extrusion regions for extruding the first and second brittle capsules, respectively.

[0019] Further, the extrusion plate and the adhesive plate are made of a flame-retardant polymer.

[0020] Technical effects and advantages of the present application:

[0021] 1. The novel junction box of the present application can quickly realize electrical circuit communication and adhesion with the photovoltaic module, and has good water and oxygen barrier and insulation performance, thereby improving the production efficiency and long-term weather resistance of the photovoltaic module.

[0022] 2. The junction box of the present application avoids the shortcomings of traditional silicone resin junction boxes, which need to be heated and humidified to slowly cure (usually the complete curing time is as long as 24 h), and avoids the shortcomings of welding junction boxes, which need more production lines and complex welding processes. The junction box of the present application realizes instantaneous electrical circuit connection through pressure, and the acrylic composite material is crosslinked instantaneously after pressure is applied, so that the installation time of the junction box is greatly shortened.

[0023] 3、The application sets flexible compressible area, first brittle capsule and second brittle capsule in the junction box, fills conductive metal polymer composite gel and modified graft polymer in the first brittle capsule and the second brittle capsule respectively, the first brittle capsule and the second brittle capsule break in turn after pressure, the conductive metal polymer composite gel is firmly combined with the positive and negative poles of the photovoltaic module, realizes circuit communication, the graft polymer is crosslinked and solidified quickly, the junction box is fixed on the surface of the photovoltaic backboard, simple and quick operation greatly improves the production efficiency of the photovoltaic module, and the graft polymer has strong water and oxygen resistance after self-crosslinking, which is obviously better than the commercial photovoltaic packaging product.

[0024] Other features and advantages of the present application will be set forth in the following description, and in part will become apparent to those skilled in the art from the description, or can be learned by practice of the present application. The objects and other advantages of the present application will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 It is a structure schematic diagram of a photovoltaic module junction box of the present application.

[0026] Figure 2 It is a structure schematic diagram of a photovoltaic module junction box after the first brittle capsule breaks.

[0027] Figure 3 It is a structure schematic diagram of a photovoltaic module junction box after the second brittle capsule breaks.

[0028] Figure 4 It is a structure schematic diagram of a photovoltaic module junction box after crosslinking and solidification.

[0029] Figure 5 It is a structure schematic diagram of a photovoltaic module junction box of the present application. DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the present application will be described clearly and completely below with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the protection scope of the present application.

[0031] As Figure 1As shown, this application provides a photovoltaic module junction box, including a cable 1, an extrusion plate 8, and an adhesive plate 7; the extrusion plate 8 and the adhesive plate 7 are stacked in parallel, the adhesive plate 87 is used to adhere to the back sheet of the photovoltaic module 9, and fix the photovoltaic module junction box to the surface of the photovoltaic module 9, the extrusion plate 8 is used to apply pressure to the adhesive plate 7, the extrusion plate 8 and the adhesive plate 7 together constitute the housing of the junction box, a gap is left between the extrusion plate 8 and the adhesive plate 7, the gap constitutes a flexible compressible area 6, the adhesive plate 7 is provided with a plurality of through holes 5, one end of the through hole 5 is connected to the flexible compressible area 6, and the other end is attached to the adhesive surface of the back sheet of the photovoltaic module 9; one end of the cable 1 passes through the extrusion plate 8 and the adhesive plate 7 in sequence, the outer shell of the cable 1 is fixedly connected to the extrusion plate 8 and the adhesive plate 7, and a metal part 2 is provided inside the outer shell, the metal part 2 is used to connect the circuit of the photovoltaic module 9. The flexible compressible region 6 is filled with multiple first brittle capsules 3 and multiple second brittle capsules 4. 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 silicone. The first brittle capsules 3 are filled with a conductive metal polymer composite gel, and the second brittle capsules 4 are filled with a modified grafted polymer. The height of the first brittle capsules 3 is greater than the height of the second brittle capsules 4. Figure 2 As shown, when the extrusion plate 8 is pressed, pressure is simultaneously applied to the flexible compressible area 6. At this time, due to the large height of the first brittle capsule 3, it breaks first under pressure, releasing the conductive metal polymer composite gel. The conductive metal polymer composite gel fills the gap between the bonding surface of the adhesive plate 7 and the photovoltaic module 9 through the through hole 5. At this time, the flexible compressible area 6 still contains the unbroken second brittle capsule 4; as Figure 3 As shown, a second, greater external force is applied to the extrusion plate 8, cracking the second brittle capsule 4, causing the modified grafted polymer to flow into the gap between the bonding plate 7 and the photovoltaic module 9 bonding surface; as Figure 4 As shown, the conductive metal polymer composite gel and the modified grafted polymer undergo a self-crosslinking reaction and cure in the gap between the bonding plate 7 and the photovoltaic module 9, thus completing the installation of the junction box and the photovoltaic module 9.

[0032] In some embodiments of this application, the conductive metal polymer composite gel comprises a metal nanocomposite material grafted with n-butyl acrylate and / or an acrylic copolymer.

[0033] Modified grafted polymers include polystyrene grafted with polyisobutylene, polydimethylsiloxane grafted with acrylic acid, α-pinene methacrylate grafted with butyl acrylate, methacryloyloxypropylsilsesquioxane grafted with methacrylic acid-butyl acrylate-2-(2-ethoxyethoxy)ethyl acrylate, and polyurethane-acrylic acid block copolymers with different main chain lengths and side chain densities.

[0034] The extrusion plate 8 and the bonding plate 7 are made of flame-retardant polymer.

[0035] In some embodiments of this application, such as Figure 5 As shown, the height of the first brittle capsule 3 is equal to the height of the second brittle capsule 4. The extrusion plate 8 includes multiple independent extrusion areas for extruding the first brittle capsule 3 and the second brittle capsule 4 respectively. The first brittle capsule 3 and the second brittle capsule 4 are broken sequentially by extruding the extrusion areas corresponding to the first brittle capsule 3 and the second brittle capsule 4.

[0036] The working principle of the photovoltaic module junction box in this application is as follows:

[0037] A junction box shell is constructed using an extrusion plate 8 and an adhesive plate 7 made of flame-retardant polymer material. A gap is left between the extrusion plate 8 and the adhesive plate 7 to form a flexible compressible area 6. A first brittle capsule 3 and a second brittle capsule 4 are embedded in the flexible compressible area 6. Multiple through holes 5 are provided on the adhesive plate 7 for the outflow of conductive metal polymer composite gel and modified grafted polymer gel. One end of the cable 1 is passed through the extrusion plate 8 and the adhesive plate 7 in sequence, and the shell of the cable 1 is fixedly connected to the extrusion plate 8 and the adhesive plate 7. The metal part 2 inside the cable 1 is used to connect to the photovoltaic module 9 circuit.

[0038] When connecting the junction box to the photovoltaic module 9, place the junction box on the adhesive surface of the backsheet of the photovoltaic module 9, aligning it with the positive and negative terminal junctions. Apply the first pressure to the extrusion plate 8, compressing the flexible compressible area 6, causing the first brittle capsule 3 to rupture and release the conductive metal polymer composite gel. The conductive metal polymer composite gel fills the gap between the junction box and the backsheet of the photovoltaic module 9 through the through-hole 75. At this time, the flexible compressible area 6 still contains the unruptured second brittle capsule 4. Apply the second pressure to the extrusion plate 8, causing the solvent containing the modified grafted polymer gel solute to flow into the gap between the junction box and the backsheet of the photovoltaic module 9. At this time, the conductive metal polymer composite gel and the modified grafted polymer gel undergo a self-crosslinking reaction and solidify in the gap between the junction box and the backsheet of the photovoltaic module 9, completing the installation of the junction box and the photovoltaic module 9.

[0039] To better illustrate this solution, the following embodiments are provided.

[0040] Example 1

[0041] Polystyrene-grafted polyisobutylene was selected as the modified graft polymer, while the conductive metal polymer composite gel was composed of silver nanocomposite material grafted with n-butyl acrylate and acrylic acid copolymer. A junction box was assembled according to the above structure, and comprehensive testing was conducted on photovoltaic module 9. During the testing process, after applying pressure to trigger the compression of the flexible compressible region 96 and the rupture of the brittle capsule, a pressure of 30N was continued to promote the self-crosslinking reaction between the conductive metal polymer composite gel and the graft polymer gel.

[0042] After the junction box was tightly connected and cured to the photovoltaic module 9, the resistance of the circuit was measured using a four-probe tester. The result showed that the resistance value was 0.3Ω, which is comparable to the conductivity of the circuit in the traditional welding method (0.25Ω), proving the reliability of the new junction box in terms of circuit connectivity.

[0043] The water and oxygen barrier performance of the new junction box was evaluated using WVTR (water vapor transmission rate) and OTR (oxygen transmission rate) tests. The following data were obtained: the WVTRs of the three new junction box samples were 0.5, 0.4, and 0.8 g / m²·day, and the OTRs were 2.3, 4.6, and 5.1 × 10⁻⁶, respectively. - The WVTR of the three conventional junction box samples were 2.4, 2.5, and 3.1 g / m²·day, respectively, and the OTRs were 20.8, 22.1, and 21.7 × 10³ cc / m²·d, respectively. - ³cc / m²·d. This comparative result clearly demonstrates the significant advantages of the new junction box in terms of water and oxygen barrier performance.

[0044] Example 2

[0045] Polydimethylsiloxane-grafted acrylic acid was used as the modified graft polymer material, and other materials were the same as in Example 1. The same testing procedure as in Example 1 was performed. The test results showed that the novel junction box of this embodiment was superior to the junction box in Example 1 in terms of water and oxygen barrier properties.

[0046] Further testing was conducted on the component efficiency of the junction box connection. Taking a 30*40cm² component as an example, the component efficiency of the three junction box samples in this embodiment is shown in Table 1, ranging from 15.42% to 16.41%. The component efficiency of the three conventional junction box samples is shown in Table 2, ranging from 15.78% to 16.63%. This result further confirms the effectiveness of the new junction box in maintaining component efficiency.

[0047] Table 1. 30*40cm junction box connection in Example 2 2 Component efficiency

[0048]

[0049] Table 2 30*40cm Traditional Junction Box Connection 2 Component efficiency

[0050]

[0051] In summary, the novel junction box of this application not only successfully solves many problems existing in traditional junction boxes, such as low production efficiency and poor water and oxygen barrier performance, but also excels in maintaining component efficiency. Therefore, the novel junction box of this application has broad application prospects and huge market potential.

[0052] Finally, it should be noted that the above description is only a preferred embodiment of this application and is 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 photovoltaic module junction box, characterized in that, Includes cable (1), extrusion plate (8) and bonding plate (7); The extrusion plate (8) and the bonding plate (7) are stacked in parallel; One end of the cable (1) passes through the extrusion plate (8) and the bonding plate (7) in sequence. The outer shell of the cable (1) is fixedly connected to the extrusion plate (8) and the bonding plate (7). A metal part (2) is provided inside the outer shell. A gap is left between the extrusion plate (8) and the bonding plate (7), and the gap forms a flexible compressible area (6). The flexible compressible area (6) is filled with a plurality of first brittle capsules (3) and a plurality of second brittle capsules (4). The first brittle capsules (3) are filled with conductive metal polymer composite gel, and the second brittle capsules (4) are filled with modified grafted polymer. The adhesive plate (7) is provided with a plurality of through holes (5), one end of which is connected to the flexible compressible area (6), and the other end is attached to the adhesive surface of the photovoltaic module (9).

2. A photovoltaic module junction box according to claim 1, characterized in that, The first brittle capsule (3) and the second brittle capsule (4) are composed of one or more of polystyrene, polyurethane, polylactic acid, polymethyl methacrylate and silicone.

3. A photovoltaic module junction box according to claim 1, characterized in that, The conductive metal polymer composite gel comprises a metal nanocomposite material grafted with n-butyl acrylate and an acrylic acid copolymer.

4. A photovoltaic module junction box according to claim 3, characterized in that, The modified grafted polymers include polystyrene grafted with polyisobutylene, polydimethylsiloxane grafted with acrylic acid, α-pinene methacrylate grafted with butyl acrylate, methacryloyloxypropylsilsesquioxane grafted with methacrylic acid-butyl acrylate-2-(2-ethoxyethoxy)ethyl acrylate, and polyurethane-acrylic acid block copolymers with different main chain lengths and side chain densities.

5. A photovoltaic module junction box according to claim 1, characterized in that, The height of the first brittle capsule (3) is greater than the height of the second brittle capsule (4).

6. A photovoltaic module junction box according to claim 1, characterized in that, The height of the first brittle capsule (3) is equal to the height of the second brittle capsule (4).

7. A photovoltaic module junction box according to claim 6, characterized in that, The extrusion plate (8) includes multiple independent extrusion zones for extruding the first brittle capsule (3) and the second brittle capsule (4) respectively.

8. A photovoltaic module junction box according to claim 1, characterized in that, The extrusion plate (8) and the bonding plate (7) are made of flame-retardant polymer.

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