Junction box installation of solar cells

Junction box installation of solar cells

1. Purpose

It is convenient for the electrical connection between the power supply and the load; it protects the electrical contact between the output end and the cable, and provides a good installation space and protection environment for the bias diode.

The installation of the component junction box and subsequent processes have a slightly smaller impact on the quality of the component than other processes, but a good junction box installation is the basis for ensuring at least 25 years of service life for the component (The latest information shows that some manufacturers provide a 30-year warranty, and a long warranty requires a lot of experimental demonstrations).

2. Bill of Materials

1) Junction box.

2) Silicone.

3) Diodes.

4) Solder.

5) Flux.

6) Cotton gloves.

3. Equipment and tools

1) Utility knife.

2) Deterrent.

3) Pneumatic glue gun.

4) Plastic ruler.

5) Constant temperature electric soldering iron.

6) Scissors.

4. Process requirements

1) The installation position of the junction box is shown in Figure 1.

Junction box installation of solar cells
Figure 1 – Junction box installation drawing

2) Take a junction box and check for defects; evenly apply a circle of silica gel on the bottom of the junction box, pay attention to the amount of silica gel.

3) Stand up the 4 bus bars of the lead wires of the component, and evenly apply silica gel around the bus bars.

4) Align the square hole of the junction box with the corresponding bus bar and insert it, press down with both hands slightly, glue the junction box to the backplane, and use silicone to glue the junction box to the backplane correctly and beautifully.

5) After the silica gel is solidified, fix the electrode leads correctly, and connect the welding tape to the bayonet of the junction box with a special tool for welding tape installation.

6) Cover the box cover, make sure that the box cover and the box body are snapped together accurately or screw on the box cover screws, and check the assembly quality.

7) Place the components with the junction box installed in the designated position, and wait until the silicone is completely solidified before moving.

8) Self-inspection of the assembled junction box components, including checking whether the serial number of the component is consistent with the “Process Flow Sheet”, etc., to prevent production quality problems caused by human negligence.

9) Fill in the “Process Flow Sheet” accurately, and transfer to the next process after passing the test.

10) If there is no diode installed in the junction box, you need to use a deterrent to shape the diode pins and solder them on the two terminals of the junction box.

5. Quality requirements

1) The junction box and the backplane must be sealed with silicone, and the thickness of the silicone is 1~2mm.

2) The positive and negative electrodes of the diode are connected correctly, and the welding of the diode and other welding spots are bright and full.

3) The assembly is correct, the position of the junction box is accurate, parallel to the four sides, and the appearance is beautiful.

4) After the assembly is completed, there must be no debris left in the junction box, nor can there be any debris stuck on the silicone. The following are the requirements for soldering leads:

To weld the lead, the lead electrode must be accurately welded in the corresponding position, and it is required to be reliable and firm, and no false welding or false welding can occur.

6. Precautions

1) Apply an appropriate amount of silicone to avoid too much, resulting in waste and unsightly edges.

2) When installing the junction box, care should be taken to handle it with care, and do not suffer from external pressure, so as to avoid damage to the junction box.

3) After opening the package, if you find that the internal parts do not meet the process requirements, please stop using it immediately and contact IPQC and the process supervisor in time.

4) In any case, the positive and negative wires of a set of connectors cannot be joined together, otherwise the junction box and battery components may be damaged.

5) For non-maintenance reasons, do not plug and unplug the wire connection frequently to ensure the waterproof and sealing performance of the system. The junction box in this example is a crimping junction box, and other junction boxes are installed according to the installation requirements. No matter what kind of junction box, in principle, its four sides can be kept parallel to the aluminum frame.