A high current photovoltaic junction box

Abstract

The application discloses a large-current photovoltaic junction box and belongs to the field of photovoltaic junction box structure design. The bottom of the base of the large-current photovoltaic junction box is a bonding area and a ventilation area. The ventilation area increases the air inflow amount, forms air circulation, improves the heat dissipation effect of the junction box, realizes the purpose of rapid heat dissipation and cooling, effectively reduces the influence of the heat of the junction box itself on the power attenuation of the battery piece, and increases the power generation amount under the condition of the same irradiance and environmental temperature. Moreover, the volume of the box body does not need to be increased, the heat dissipation capacity is improved, and the cost is saved. The bus bar passes through the hole of the back plate or glass, the bonding area in sequence, and is finally electrically connected to the terminal piece. The back plate or glass of the ventilation area improves the capacity of the bus bar to absorb and dissipate the heat of the diode. The base part at the ventilation area increases the heat dissipation surface of the junction box and also improves the heat dissipation capacity. The bonding area is processed with a hole or a small groove. The bonding glue is extruded into the junction box through the hole or the small groove to form an inverted buckle after solidification, and the bonding capacity is improved.

Description

Technical Field

[0001] This invention belongs to the field of structural design of photovoltaic junction boxes, and specifically relates to a high-current photovoltaic junction box. Background Technology

[0002] A photovoltaic (PV) junction box is the circuit path connecting PV cells and the system. Currently, common junction boxes are flat or rectangular boxes made of die-cast engineering plastic, with a smooth, flat bottom. Installation involves applying solar silicone sealant to the bottom of the junction box, then installing it in the center of the module's backsheet or glass near the top edge. Once the silicone sealant has cured, the junction box is firmly bonded to the module's backsheet or glass. Currently, the structure and installation method of junction boxes for all crystalline silicon modules, both domestically and internationally, are basically the same.

[0003] The diodes in the junction box generate heat regardless of whether they are in bypass or reverse cutoff mode. Especially as the output current of high-efficiency modules increases, the heat generated by the diodes in the junction box typically increases as well. When the heat generated by the diode exceeds the cooling capacity of the junction box, the temperature rise and leakage current will cause the diode to break down. When operating in high-temperature environments, the diode's current-carrying capacity will also decrease, similar to how an inverter automatically reduces its load after reaching high temperatures. Current and temperature are crucial factors affecting the long-term reliable operation of diodes. Only with the long-term reliable operation of the photovoltaic junction box can the system generate electricity stably and reliably.

[0004] The heat dissipation capacity of a junction box primarily depends on its structural design. This is especially true for high-efficiency modules, which draw large currents and generate significant heat; therefore, proper heat dissipation in the junction box is crucial to ensure the diode's current-carrying capacity at high temperatures and its long-term reliability. Furthermore, a well-designed junction box with good heat dissipation can reduce its size and cost while maintaining quality. Therefore, improving the heat dissipation capacity of the junction box, thereby increasing the diode's current-carrying capacity, is a key objective in the current structural design of photovoltaic junction boxes. Summary of the Invention

[0005] The present invention aims to provide a high-current photovoltaic junction box to solve the problems existing in the current photovoltaic junction boxes mentioned in the background art. The purpose is to improve the heat dissipation capacity of the photovoltaic junction box, improve the current carrying capacity of the silicon-based diodes inside the photovoltaic junction box, and realize the long-term reliable operation of the photovoltaic junction box and the stable and reliable power generation of the system.

[0006] The technical solution of the present invention is as follows:

[0007] A high-current photovoltaic junction box includes a base, in which a diode and terminal pieces electrically connected via the diode are installed. The base is filled with potting compound to cover the diode. The bottom of the base includes an adhesive area and a ventilation area. The adhesive area has a boss, which makes the height of the adhesive area higher than that of the ventilation area. The ventilation area has a support leg or an auxiliary adhesive area, the height of which is the same as the height of the boss. When the base is installed on a module backplate or glass, the adhesive area is bonded to the backplate or glass with adhesive, and the boss in the adhesive area and the support leg or auxiliary adhesive area in the ventilation area are in contact with the backplate or glass. The ventilation area is not in contact with the backplate or glass, and an air channel is formed between the ventilation area and the backplate or glass. The bottom plate of the adhesive area has holes or grooves, through which adhesive is squeezed into the junction box and solidifies to form an inverted shape.

[0008] Furthermore, a first busbar guide through hole is provided in the middle of the bonding area, and a second busbar guide through hole is provided on the terminal piece; the busbar is located under the back plate or glass, passes through the ventilation area and enters the bonding area, bends through the hole in the back plate or glass, the first busbar guide through hole in the bonding area, and the second busbar guide through hole on the terminal piece, and is bent to be electrically connected to the terminal piece.

[0009] Furthermore, a trapezoidal guide block is provided inside the base, the trapezoidal guide block is located below the diode and at the middle position of the first busbar guide through hole.

[0010] Furthermore, a solder block is provided on the front side of the terminal piece, and a second busbar guide hole and a solder-blocking strip are respectively provided on both sides of the solder block.

[0011] Furthermore, a wire clamp is provided at one end of the base. The wire clamp engages with the base in a wedge shape, and the cable passes through the middle of the base and the wire clamp before connecting to the terminal piece.

[0012] Furthermore, the base is filled with potting compound to cover the diode, and the portion of the base above the wire clip has a hollow protrusion, the height of which is higher than the potting compound height after covering the diode.

[0013] The beneficial technical effects of this invention are:

[0014] The high-current photovoltaic junction box of this invention has a base divided into an adhesive zone and a ventilation zone. The ventilation zone is located on both sides of the adhesive zone, increasing the air inflow and creating air circulation, thus improving the overall heat dissipation of the junction box and reducing the temperature rise compared to existing structures. The ventilation zone increases the heat dissipation surface of the junction box, achieving rapid heat dissipation and effectively cooling the backsheet or glass. The ventilation zone occupies more than half of the bottom area, effectively reducing the impact of the junction box's own heat on the power degradation of the solar cells, increasing power generation under the same irradiance and ambient temperature conditions. This structural design eliminates the need to increase the box volume, improving heat dissipation while saving costs. Simultaneously, the built-in busbar of the module passes sequentially through holes in the backsheet or glass, through the adhesive zone, and finally electrically connects to the terminal piece. The backsheet or glass in the ventilation zone enhances the busbar's ability to absorb and dissipate diode heat. The base portion in the ventilation zone increases the heat dissipation surface of the junction box, further improving heat dissipation. Holes or grooves are machined in the adhesive zone, allowing adhesive to be squeezed into the junction box through these holes or grooves and solidify to form an inverted shape, enhancing adhesion. In addition, the present invention also solves the problem of difficulty in aligning the corresponding holes when installing the busbar, and solves the problem of solder melting and flowing out at high temperature.

[0015] The advantages of the present invention will be set forth in the following detailed description, and in some respects will become apparent from the description or may be learned by practice of the invention. Attached Figure Description

[0016] Figure 1 This is a front structural view of the high-current photovoltaic junction box of the present invention.

[0017] Figure 2 This is a structural diagram of the back of the high-current photovoltaic junction box of the present invention.

[0018] Figure 3 This is a side view of the high-current photovoltaic junction box of the present invention.

[0019] Figure 4 This is a cross-sectional view of the high-current photovoltaic junction box of the present invention mounted on a back panel or glass.

[0020] Figure 5 yes Figure 4 A magnified view of a portion of the image.

[0021] Figure 6 This is a structural diagram of the terminal piece of the present invention.

[0022] Figure 7 This is a structural diagram of the bonding area of ​​the crimping buckle in another embodiment.

[0023] In the diagram: 1--base, 2--terminal piece, 3--diode, 4--busbar, 5--cable, 6--wire clamp, 7--backplate or glass, 8--bonding area, 9--ventilation area, 10--bore, 11--foot, 12--first busbar guide hole, 13--second busbar guide hole, 14--trapezoidal guide block, 15--solder block, 16--solder bar, 17--hole or slot, 18--wire clamp bonding area. Detailed Implementation

[0024] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings.

[0025] In the structural design of photovoltaic junction boxes, junction boxes include single-unit junction boxes and split-type junction boxes. This embodiment uses a split-type junction box as an example for illustration.

[0026] A split-type junction box is a junction box that is divided into a positive terminal junction box, a negative terminal junction box, and several intermediate terminal boxes. Split-type junction boxes minimize connection length, distribute heat from diodes, and allow electrical components within the intermediate terminal boxes to be pre-sealed. During on-site installation, only the positive and negative terminal boxes need to be sealed, reducing on-site work and improving wiring reliability. This structural design is also applicable to single-unit junction boxes, two-unit junction boxes, or junction boxes with more split components.

[0027] Since the mounting structures of the positive electrode box, negative electrode box, and intermediate box components are basically the same in this invention, we will now describe one of the boxes, such as the positive electrode junction box or the negative electrode junction box, as an example.

[0028] See Figure 1 The junction box of this invention includes a base 1, within which a horizontally arranged diode 3 is installed, and a terminal piece 2 electrically connected via the diode 3. Two busbars 4 pass through the bottom of the base 1, their ends are bent, and respectively soldered to the terminal piece 2. One end of the junction box is provided with a wire clamp 6, and the lead end of the cable 5 passes through the middle of the base 1 and the wire clamp 6 and is soldered to the terminal piece 2. Of course, if the junction box is a composite structure, the aforementioned cable 5 and wire clamp 6 are not included.

[0029] See Figure 2 The bottom of the base 1 is divided into an adhesive area 8 and a ventilation area 9. The adhesive area 8 is located below the diode 3, in the middle of the bottom, while the ventilation areas 9 are located on both sides of the adhesive area 8. See also Figure 2 and Figure 3A ring of protrusions 10 is provided around the bottom of the bonding area 8. These protrusions 10 have a certain height, so that the bonding area 8 and the ventilation area 9 are on different planes, and the height of the bonding area 8 is higher than that of the ventilation area 9. Several support feet 11 are provided at the edge of the ventilation area 9, and the height of the support feet 11 is the same as the height of the protrusions 10. When the base 1 is installed on the component back plate or glass 7, the protrusions 10 of the bonding area 8 and the support feet 11 of the ventilation area 9 are in contact with the back plate or glass 7, which can keep the base 1 stable when installed on the component back plate or glass 7.

[0030] See Figure 2 After the base 1 is filled with potting compound, the diode 3 is covered. The bonding area 8 is bonded to the backplate or glass 7 with adhesive. The heat from the diode 3 and the terminal piece 2 can be quickly conducted to the backplate or glass 7 through the potting compound and the bonding area 8 for heat dissipation. See also Figure 3 Ventilation zone 9 does not contact the back panel or glass 7, forming an air channel between them. Air flows into the space between the base 1 and the back panel or glass 7, creating air circulation. Ventilation zone 9 increases the heat dissipation surface of the junction box, effectively cooling the back panel or glass and achieving rapid heat dissipation. This effectively reduces the impact of the junction box's own heat on the power degradation of the battery cells, increasing power generation. Moreover, it does not require increasing the box size, improving heat dissipation capacity and saving costs.

[0031] See Figure 1 and Figure 2 The bonding area 8 has a first busbar guide hole 12 in the middle and a second busbar guide hole 13 on the terminal piece 2. The function of the first busbar guide hole 12 and the second busbar guide hole 13 is to guide the busbar during installation, so as to facilitate the installation of the busbar in a narrow space.

[0032] See Figure 4 and Figure 5 In this embodiment, the busbar 4 is a double-sided component busbar. During installation, the two busbars 4 are located under the backplate or glass 7, pass through the ventilation zone 9 into the bonding zone 8, bend through the hole in the backplate or glass 7, the first busbar guide through hole 12 in the bonding zone 8, and the second busbar guide through hole 13 on the terminal piece 2, and finally bend and electrically connect to the terminal piece 2. The backplate or glass 7 of the ventilation zone 9 improves the ability of the busbar 4 to absorb and dissipate the heat of the diode 3; the base portion at the ventilation zone 9 increases the heat dissipation surface of the junction box, and also improves the heat dissipation capacity.

[0033] See Figure 5A trapezoidal guide block 14 is provided inside the base 1. The trapezoidal guide block 14 is located below the diode 3 and in the middle of the first busbar guide through-hole 12. The smaller end of the trapezoidal guide block 14 faces the first busbar guide through-hole 12, and the larger end faces the diode 3. The function of this structure is that when the busbar 4 is installed, the trapezoidal guide 14 allows the busbar 4 to be easily guided into the first busbar guide through-hole 12 and then inserted into the second busbar guide through-hole 13. This is because the small end of the trapezoidal guide block 14 faces the first busbar guide through hole 12, which makes the hole for inserting the busbar 4 relatively large, allowing the busbar 4 to be easily inserted. The inclined surfaces on both sides of the trapezoidal guide block 14 can guide the direction of travel of the busbar 4 after insertion, and the end of the inclined surface of the trapezoidal guide block 14 is aligned with the position of the second busbar guide through hole 13 on the terminal piece 2, so that the busbar 4 can be accurately inserted into the second busbar guide through hole 13, solving the problem of difficulty in aligning the busbar with the corresponding hole during installation.

[0034] See Figure 6 Terminal piece 2 comprises two terminal piece segments, with a diode 3 installed between them. The leads of the diode 3 electrically connect the two terminal piece segments. Solder blocks 15 are provided on the front sides of each of the two terminal piece segments. Two second busbar guide holes 13 are respectively located inside the two solder blocks 15, and two solder baffles 16 are respectively located outside the two solder blocks 15. Two double-sided component busbars 4 pass through the second busbar guide holes 13 and then bend at 90 degrees, respectively soldering to the two solder blocks 15. The purpose of this structure is to provide solder blocks 15 on the terminal piece 2 for easy soldering, eliminating the need for additional solder preparation. The solder baffles 16 limit the flow of molten solder. Since the solder blocks 15 tend to flow freely after melting at high temperatures, the solder baffles 16 prevent molten solder from flowing out of the terminal piece 2 and into the junction box, thus solving the problem of solder leakage.

[0035] See Figure 2 Since the bottom of the base 1 is only bonded to the backplate or glass 7 via the adhesive area 8, the bonding area is smaller compared to existing technologies, which reduces the connection strength. To solve this problem, holes or grooves 17 are machined on the base plate between the boss 10 of the adhesive area 8 below the diode 3 and the first busbar guide hole 12. When adhesive is applied between the adhesive area 8 and the backplate or glass 7, the adhesive is squeezed into the junction box through the holes or grooves 17 and solidifies to form an inverted bond, improving the bonding ability. On the other hand, the holes or grooves increase the heat dissipation area, allowing the heat from the diode and terminal block to be quickly conducted to the photovoltaic module backplate or glass through the potting compound, thus improving the heat dissipation capacity of the housing.

[0036] See Figure 7In another embodiment, a wire clamp bonding area 18 can be provided below the wire clamp 6. The wire clamp bonding area 18 is coated with adhesive and bonded to the back plate or glass 7. The wire clamp bonding area 18 and the bonding area 8 in the middle of the junction box are connected together to the back plate or glass 7. These two mounting areas facilitate reinforced installation and improve installation stability. Furthermore, from... Figure 7 As can be seen, the wire clamp 6 and the base 1 have a wedge-shaped fit, resulting in better sealing. Furthermore, combined with... Figure 1 and Figure 3 As can be seen, the part of the base 1 above the wire clip 6 has a hollow protrusion, that is... Figure 1 At the "+" sign, the height of this protrusion is higher than the height of the potting compound after covering the diode. Because the space in this protrusion is relatively large, the potting compound can easily enter the protrusion during potting, achieving potting and air venting. After potting, the air inside the protrusion is expelled, resulting in a fuller potting, unlike some junction boxes that have gaps after potting.

[0037] The above descriptions are merely preferred embodiments of the present invention, and the present invention is not limited to the above embodiments. It is understood that other improvements and variations that can be directly derived or conceived by those skilled in the art without departing from the spirit and concept of the present invention should be considered to be included within the protection scope of the present invention.

Claims

1. A high-current photovoltaic junction box, comprising a base, a diode and a terminal piece electrically connected to the diode are installed inside the base, and the base is filled with potting compound to cover the diode; characterized in that The base includes an adhesive area and a ventilation area at its bottom. The adhesive area is located below the diode and in the middle of the base bottom, while the ventilation areas are located on both sides of the adhesive area. A boss is provided around the bottom of the adhesive area, making the height of the adhesive area higher than that of the ventilation area. The ventilation area has a support leg or auxiliary adhesive area, the height of which is the same as the height of the boss. When the base is installed on the component backplate or glass, the adhesive area is bonded to the backplate or glass with adhesive, and the boss in the adhesive area and the support leg or auxiliary adhesive area in the ventilation area are in contact with the backplate or glass. The ventilation area is not in contact with the backplate or glass, forming an air channel between the ventilation area and the backplate or glass. The bottom plate of the adhesive area has holes or grooves through which adhesive is squeezed into the junction box and solidifies to form an inverted shape. A first busbar guide hole is provided in the middle of the bonding area, and a second busbar guide hole is provided on the terminal piece; the busbar is located under the back plate or glass, passes through the ventilation area and enters the bonding area, bends through the hole in the back plate or glass, the first busbar guide hole in the bonding area, and the second busbar guide hole on the terminal piece, and is bent to be electrically connected to the terminal piece.

2. The high-current photovoltaic junction box according to claim 1, characterized in that: A trapezoidal guide block is provided inside the base. The trapezoidal guide block is located below the diode and at the middle position of the first busbar guide through hole.

3. A high-current photovoltaic junction box according to claim 1, characterized in that: A solder block is provided on the front side of the terminal piece, and a second busbar guide hole and a solder-blocking strip are respectively provided on both sides of the solder block.

4. A high-current photovoltaic junction box according to claim 1, characterized in that: A wire clamp is provided at one end of the base. The wire clamp fits into the wedge shape of the base. The cable passes through the middle of the base and the wire clamp and is connected to the terminal piece.

5. A high-current photovoltaic junction box according to claim 4, characterized in that: The base is filled with potting compound to cover the diode. The portion of the base above the wire clip has a hollow protrusion, the height of which is higher than the height of the potting compound after covering the diode.

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