Cross Testing Electrically Conductive Adhesives and Conductive Back-sheets for the ECN Back-contact Cell and Module Technology

ECN set up a cross testing project in which suppliers of electrically conductive adhesives (ECA) and conductive back-sheet (CBS) foils participated. In the component part of the project, combinations of adhesive and foil were characterised for peel strength and contact resistance. The separate components were tested on dot geometry (ECA) and surface structure (CBS). In the module manufacture and testing part, 12 combinations of ECA and CBS were used in 4-cell MWT modules. The modules were tested up to 2000 hours in damp heat and 400 thermal cycles (both tests, 2 times the requirement of IEC61215).Most combinations passed the 5% power loss criterion. One of the conductive adhesives performed well on three different types of back-sheet which is supportive of a robust technology. Other results show that it is important to thoroughly test interesting combinations of ECA and CBS at module level before adding them to the recommended bill of materials.