Photovoltaic module junction box

Abstract

The invention belongs to the field of photovoltaic industry, and discloses a photovoltaic module junction box, which comprises a cable, an extrusion plate and a bonding plate, the extrusion plate and the bonding plate are stacked in parallel; one end of the cable sequentially penetrates through the extrusion plate and the bonding plate, a shell of the cable is fixedly connected with the extrusion plate and the bonding plate, a metal piece is arranged in the shell, a gap is reserved between the extrusion plate and the bonding plate, the gap forms a flexible compressible area, the flexible compressible area is filled with conductive and curable gel, a plurality of through holes are formed in the bonding plate, and the metal piece is arranged in the through holes. One end of the through hole is communicated with the flexible compressible area, and the other end is attached to the bonding surface of the photovoltaic module. The novel photovoltaic module junction box can quickly realize circuit connection and bonding with the photovoltaic module, has good water and oxygen barrier and insulating properties, and improves the production efficiency and long-term weather resistance of the photovoltaic module.

Description

Technical Field

[0001] This application belongs to the field of photovoltaic industry, and particularly relates to a photovoltaic module junction box. Background Art

[0002] As an important component connecting photovoltaic modules to the power system, the performance of the junction box of photovoltaic modules directly affects the power generation efficiency and long-term stability of photovoltaic modules. Traditional junction boxes are connected to the positive and negative busbar ends of photovoltaic modules by welding, fixed to the back of photovoltaic modules through water-blocking silica gel, silicone resin or double-sided foam tape, and filled with epoxy resin or silicone resin as potting glue inside the junction box. The above traditional processes and materials not only reduce the production efficiency of modules, but also make it difficult to ensure that water vapor, oxygen, etc. do not invade the inside of the module through the holes drilled on the back of the module during the curing process of the glue, resulting in a decline in module performance. Moreover, the water-blocking and oxygen-blocking performance of such materials is not good, and it is impossible to ensure the long-term weather resistance of water- and oxygen-sensitive photovoltaic modules.

[0003] Therefore, it is necessary to provide a junction box that can quickly achieve electrical connection and bonding with photovoltaic modules, and at the same time has good water and oxygen barrier and insulation properties, improving the production efficiency and long-term weather resistance of photovoltaic modules. Summary of the Invention

[0004] In order to overcome the defects of the above-mentioned prior art, the purpose of this application is to provide a junction box that can quickly achieve electrical connection and bonding with photovoltaic modules, and at the same time has good water and oxygen barrier and insulation properties, improving the production efficiency and long-term weather resistance of photovoltaic modules.

[0005] To achieve the above purpose, this application provides the following technical solutions:

[0006] A photovoltaic module junction box, comprising a cable, a pressing plate and an adhesive plate;

[0007] The pressing plate and the adhesive plate are stacked in parallel;

[0008] One end of the cable passes through the pressing plate and the adhesive plate in sequence, the outer shell of the cable is fixedly connected to the pressing plate and the adhesive plate, and a metal part is arranged inside the outer shell;

[0009] A gap is left between the pressing plate and the adhesive plate, and the gap forms a flexible compressible area, and a conductive and curable gel is filled in the flexible compressible area;

[0010] A plurality of through holes are arranged on the adhesive plate, one end of the through hole communicates with the flexible compressible area, and the other end abuts against 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 brittle capsule and the second brittle capsule include one or more of polystyrene, polyurethane, polylactic acid, polymethyl methacrylate, and silica gel.

[0013] Further, 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.

[0014] Further, the 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, α-pinene methacrylate-grafted butyl acrylate, methacryloxypropyl sesquisiloxane-grafted methacrylic acid-butyl acrylate 2-(2-ethoxyethoxy)ethyl acrylate, and polyurethane-acrylic block copolymer with different main 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 areas for extruding the first brittle capsule and the second brittle capsule respectively.

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

[0020] The technical effects and advantages of this application:

[0021] 1. The novel photovoltaic module junction box of this application can quickly achieve circuit connection and bonding with the photovoltaic module, and at the same time has good water and oxygen barrier and insulation properties, improving the production efficiency and long-term weather resistance of the photovoltaic module.

[0022] 2. The junction box of this application avoids the disadvantages of the traditional junction box silicone resin that requires heating and humidification to cure slowly (usually the complete curing time is up to 24h), and avoids the disadvantages of the welded junction box that requires more production line equipment and complex welding processes. It realizes instantaneous circuit connection through pressurization, and at the same time, the acrylic composite material has a short curing time and usually crosslinks instantaneously after pressure is applied, greatly shortening the installation time of the junction box.

[0023] 3. In this application, a flexible compressible area, a first brittle capsule, and a second brittle capsule are provided inside the junction box. Conductive metal polymer composite gel and modified graft polymer are respectively filled in the first brittle capsule and the second brittle capsule. After pressure is applied, the first brittle capsule and the second brittle capsule rupture in sequence. The conductive metal polymer composite gel firmly binds to the positive and negative electrodes of the busbar of the photovoltaic module, realizing circuit connection. The graft polymer rapidly crosslinks and cures, fixing the junction box on the surface of the photovoltaic backsheet. The operation is simple and fast, greatly improving the production efficiency of the photovoltaic module. Moreover, after self-crosslinking, the graft polymer has strong water and oxygen barrier properties, which are significantly better than commercially available photovoltaic encapsulation products.

[0024] Other features and advantages of this application will be described in the subsequent description. And, partly, they will become obvious from the description, or can be understood by implementing this application. The objectives and other advantages of this application can be realized and obtained through the structures pointed out in the description, claims, and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of Structure A of a junction box for a photovoltaic module of this application;

[0026] Figure 2 It is a schematic diagram of Structure A of a junction box for a photovoltaic module after the first brittle capsule ruptures;

[0027] Figure 3 It is a schematic diagram of Structure A of a junction box for a photovoltaic module after the second brittle capsule ruptures;

[0028] Figure 4 It is a schematic diagram of Structure A of a junction box for a photovoltaic module after crosslinking and curing;

[0029] Figure 5 It is a schematic diagram of Structure B of a junction box for a photovoltaic module of this application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0030] Next, the technical solutions in the embodiments of this application will be clearly and completely described in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are only part of the embodiments of this application, rather than all the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of this application.

[0031] As Figure 1As shown in the figure, the present application provides a photovoltaic module junction box, which 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. The adhesive plate 8 is used to fit the back plate of the photovoltaic module 9 to fix the photovoltaic module junction box on the surface of the photovoltaic module 9. The pressing plate 8 is used to apply pressure towards the adhesive plate 7. The pressing plate 8 and the adhesive plate 5 together form the housing of the junction box. There is a gap between the pressing plate 8 and the adhesive plate 7, and the gap forms a flexible compressible zone 6. A plurality of through holes 5 are provided on the adhesive plate 7. One end of the through hole 5 communicates with the flexible compressible zone 6, and the other end fits the adhesive surface of the back plate of the photovoltaic module 9; one end of the cable 1 passes through the pressing plate 8 and the adhesive plate 7 in sequence. The outer shell of the cable 1 is fixedly connected to the pressing plate 8 and the adhesive plate 7. A metal part 2 is arranged inside the outer shell, and the metal part 2 is used to connect the circuit of the photovoltaic module 9. A plurality of first brittle capsules 3 and a plurality of second brittle capsules 4 are filled in the flexible compressible zone 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. 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 graft polymer. The height of the first brittle capsules 3 is greater than the height of the second brittle capsules 4; As Figure 2 shown in the figure, when pressing the pressing plate 8, pressure is simultaneously applied to the flexible compressible zone 6. At this time, due to the greater height of the first brittle capsules 3, they are first stressed and broken, releasing the conductive metal polymer composite gel. The conductive metal polymer composite gel passes through the through holes 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 zone 6 still contains unbroken second brittle capsules 4; As Figure 3 shown in the figure, a second greater external force is applied to the pressing plate 8 to fracture the second brittle capsules 4, so that the modified graft polymer also flows into the gap between the adhesive plate 7 and the adhesive surface of the photovoltaic module 9; As Figure 4 shown in the figure, the conductive metal polymer composite gel and the modified graft polymer undergo a self-crosslinking reaction and curing in the gap between the adhesive plate 7 and the adhesive surface of the photovoltaic module 9 to complete the installation of the junction box and the photovoltaic module 9.

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

[0033] The modified graft polymer includes polystyrene-grafted polyisobutylene, polydimethylsiloxane-grafted acrylic acid, α-pinene methacrylate-grafted butyl acrylate, methacryloxypropyl sesquisiloxane-grafted methacrylic acid-butyl acrylate 2-(2-ethoxyethoxy)ethyl acrylate, and polyurethane-acrylic block copolymer with different main chain lengths and side chain densities;

[0034] The pressing plate and the adhesive plate are made of a flame-retardant polymer.

[0035] In some embodiments of the present application, as Figure 5 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 a plurality of independent extrusion regions for extruding the first brittle capsule 3 and the second brittle capsule 4 respectively. By extruding the corresponding extrusion regions of the first brittle capsule 3 and the second brittle capsule 4, the first brittle capsule 3 and the second brittle capsule 4 are ruptured in sequence.

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

[0037] The extrusion plate 8 and the bonding plate 7 made of flame-retardant polymer material are used to construct the junction box housing. A gap is left between the extrusion plate 8 and the bonding plate 7 to form a flexible compressible zone 6. The first brittle capsule 3 and the second brittle capsule 4 are respectively embedded in the flexible compressible zone 6. A plurality of through holes 5 are provided on the bonding plate 7 for the outflow of the conductive metal polymer composite gel and the modified graft polymer gel. 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. The metal part 2 inside the cable 1 is used for electrical connection with the circuit of the photovoltaic module 9.

[0038] When connecting the junction box to the photovoltaic module 9, place the junction box on the bonding surface of the back plate of the photovoltaic module 9 and align the positive and negative busbar ends. Apply a first pressure to the extrusion plate 8 to compress the flexible compressible zone 6, and the first brittle capsule 3 ruptures, releasing the conductive metal polymer composite gel. The conductive metal polymer composite gel fills the gap between the junction box and the back plate of the photovoltaic module 9 through the through hole 7. At this time, the flexible compressible zone 6 still contains the unruptured second brittle capsule 4. Apply a second pressure to the extrusion plate 8, so that the solvent with the modified graft polymer gel solute also flows into the gap between the junction box and the back plate of the photovoltaic module 9. At this time, the conductive metal polymer composite gel and the modified graft polymer gel undergo a self-crosslinking reaction and solidify in the gap between the junction box and the back plate of the photovoltaic module 9, completing the installation of the junction box and the photovoltaic module 9.

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

[0040] Embodiment 1

[0041] Polystyrene grafted with polyisobutylene is selected as the modified graft polymer, and the conductive metal polymer composite gel is composed of a silver nanocomposite grafted with n-butyl acrylate and acrylic acid copolymer. Assemble the junction box according to the above structure and conduct comprehensive tests on the photovoltaic module 9. During the test, after applying pressure to trigger the compression of the flexible compressible zone 9 and the rupture of the brittle capsule, continue to apply a pressure of 30 N to promote the self-crosslinking reaction of the conductive metal polymer composite gel and the graft polymer gel.

[0042] After the junction box was tightly connected to and cured with the photovoltaic module 9, the resistance of the circuit was measured using a four-probe tester. The result showed that the resistance value was 0.3 Ω, which was comparable to the circuit conductivity (0.25 Ω) of the traditional welding method, 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. Through WVTR (water vapor transmission rate) and OTR (oxygen transmission rate) tests, the following data were obtained: The WVTRs of three new junction box samples were 0.5, 0.4, and 0.8 g / m 2 ·day, and the OTRs were 2.3, 4.6, and 5.1×10-3 cc / m 2 ·d, while the WVTRs of three traditional junction box samples were 2.4, 2.5, and 3.1 g / m 2 ·day, and the OTRs were 20.8, 22.1, and 21.7×10-3 cc / m 2 ·d. This comparison result clearly demonstrated 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 those in Example 1. The same test procedures as in Example 1 were carried out. The test results showed that the new junction box in this example was superior to the junction box in Example 1 in terms of water and oxygen barrier.

[0046] The efficiency of the module connected to the junction box was further tested. Taking a 30*40 cm 2 module as an example, the efficiencies of the modules connected to the three junction box samples in this example are shown in Table 1. The module efficiency ranged from 15.42% to 16.41%, while the efficiencies of the modules connected to the three traditional junction box samples are shown in Table 2, and the module efficiency ranged from 15.78% to 16.63%. This result further confirmed the effectiveness of the new junction box in maintaining the module efficiency.

[0047] Table 1 Efficiency of the 30*40 cm 2 module connected to the junction box in Example 2

[0048] Sample number <![CDATA[V OC (V)]]> Isc (mA) <![CDATA[J SC (mA / cm 2 )]]> FF (%) PCE (%) 1 51.62 0.37 22.57 68.2 15.56 2 55.80 0.37 22.52 66.7 16.41 3 53.00 0.37 22.84 0.65 15.42

[0049] Table 2 Efficiency of the 30*40 cm 2 module connected to the traditional junction box

[0050] Sample number <![CDATA[V OC (V)]]> Isc (mA) <![CDATA[J SC (mA / cm 2 )]]> FF (%) PCE (%) 4 55.34 0.37 22.49 64.6 15.78 5 55.60 0.37 22.50 65.8 16.14 6 55.95 0.37 22.45 67.56 16.63

[0051] In summary, the novel junction box of the present application has not only successfully solved many problems existing in traditional junction boxes, such as low production efficiency and poor water and oxygen barrier performance, but also performed excellently in maintaining the efficiency of components. Therefore, the novel junction box of the present application has broad application prospects and great market potential.

[0052] Finally, it should be noted that the above are only the preferred embodiments of the present application and are not intended to limit the present application. Although the present 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 perform equivalent replacements on some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A photovoltaic module junction box, characterized in that: It comprises a cable (1), an extruded plate (8) and an adhesive 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 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 arranged in the outer shell; A gap is left between the extrusion plate (8) and the bonding plate (7), the gap forming a flexible compressible area (6), and the flexible compressible area (6) is filled with a conductive and curable gel; 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 photovoltaic module (9).

2. A photovoltaic module junction box according to claim 1, characterized in that: The flexible compressible area (6) is filled with a plurality of first brittle capsules (3) and a plurality of second brittle capsules (4).

3. A photovoltaic module junction box according to claim 2, characterized in that: The components of the first fragile capsule (3) and the second fragile capsule (4) include one or more of polystyrene, polyurethane, polylactic acid, polymethyl methacrylate and silica gel.

4. A photovoltaic module junction box according to claim 2, characterized in that: The first brittle capsule (3) is filled with a conductive metal polymer composite gel, and the second brittle capsule (4) is filled with a modified graft polymer.

5. A photovoltaic module junction box according to claim 4, characterized in that: The conductive metal polymer composite gel comprises a metal nanocomposite material grafted with n-butyl acrylate and an acrylic acid copolymer.

6. A photovoltaic module junction box according to claim 5, characterized in that: The modified graft polymer includes polystyrene grafted polyisobutylene, polydimethylsiloxane grafted acrylic acid, α-pinene methacrylate grafted butyl acrylate, methacryloyloxypropyl silsesquioxane grafted methacrylic acid-butyl acrylate 2-(2-ethoxyethoxy)ethyl acrylate, and polyurethane-acrylic acid block copolymer with different main chain lengths and side chain densities.

7. A photovoltaic module junction box according to claim 2, characterized in that: The height of the first brittle capsule (3) is greater than the height of the second brittle capsule (4).

8. A photovoltaic module junction box according to claim 2, characterized in that: The height of the first brittle capsule (3) is equal to the height of the second brittle capsule (4).

9. A photovoltaic module junction box according to claim 8, characterized in that: The pressing plate (8) comprises a plurality of independent pressing areas for respectively pressing the first brittle capsule (3) and the second brittle capsule (4).

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

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