PV junction-box potting materials

Selection considerations

Role in the module

Potting silicone fills the junction box after the ribbon leads are soldered to the terminals. It keeps moisture away from the diodes and joints, carries heat away from the diodes, and holds parts against vibration. Within module assembly it follows the junction-box soldering station and comes before lid closing and curing. Because potting is the last barrier around the electrical connection, its ageing behaviour matters as much as how easy it is to dispense.

The listed product

Wynca lists EncapSil5202GW, a condensation-cure, two-part silicone that cures at room temperature. Lide's sheet sets a 6:1 weight ratio and a short working window. Get the current controlled sheet and have Zhejiang Lide confirmed as producer before you order volume.

Matching material, box and line

The silicone has to suit the box it fills. Ask your junction-box components supplier, for example the maker of the Renhe junction-box family, to name potting materials already tested with that housing. Then plan the equipment:

• a metered two-part dispenser such as the HORAD AB potting station, set by weight, with separate stirring of each part and degassing;
• a buffer like the curing-stage handling system sized from full-cure time rather than gel time;
• a lid snap-fitting station placed after enough cure for the lid to sit without disturbing the potting.

The box itself is usually stuck to the backsheet or glass with an adhesive from the module bonding materials class, such as Zhijiang's frame and box sealant, applied by a box bonding dispenser. Check that sealant and potting are compatible where they meet.

Ageing and acceptance

Run sample boxes through damp-heat and thermal-cycling programmes in environmental test equipment such as the Edeson temperature and humidity chamber, then inspect for cracks, voids and loss of adhesion. The module material qualification guide describes how to freeze an approved formulation and handle later changes. Integrators quoting a full module production line should state which potting material their dispenser and curing buffer were set up for.

Plan the equipment scope

Identify the production step, cell or module format and output unit before comparing equipment. Use the listed source, scope and specifications to prepare a configuration-specific enquiry. Missing values are left unspecified and do not count as exact filter matches.

Read equipment buying guides or prepare a sourcing brief.