LOW COST SOLAR CELL LEADS FOR USE IN PHOTOVOLTAIC MODULES

THE COPPER/SOLDER/METALLIZATION/SILICON LAYERS USED TO BOND ELECTRICAL LEADS TO SOLAR CELLS HAVE VASTLY DIFFERENT THERMAL EXPANSION RATES. THIS CAUSES SEVERE STRESSES WHEN CONTINUOUS SOLDER JOINTS ARE USED. THIS PROBLEM HAS BEEN SOLVED WITH A SPECIAL LEAD DESIGN THAT USES A MULTITUDE OF FINGERS SOLDERED TO THE CELLS. THE PURPOSE OF THIS PROJECT IS TO DEVELOP A MORE COST-EFFECTIVE LEAD/CELL DESIGN. TWO TECHNICAL APPROACHES WILL BE INVESTIGATED, TO BE USED SINGULARLY OR TOGETHER. THE FIRST APPROACH IS TO ADD A STRAIN RELIEF FEATURE TO A CONTINUOUS LEAD. THE SECOND APPROACH IS TO ADD A SOLDER RESIST PATTERN SO THAT CONTINUOUS LEADS ARE ONLY BONDED TO THE CELL IN SPOTS. FINITE ELEMENT STRESS ANALYSIS WILL BE USED IN PHASE I TO INVESTIGATE DIFFERENT DESIGNS, AND PROOF-OF-CONCEPT SAMPLES OF THE MOST PROMISING CANDIDATES WILL BE MANUFACTURED AND SUBJECTED TO ENVIRONMENTAL TESTING. PHASE II WILL INTRODUCE THE MOST SUCCESSFUL DESIGN INTO THE PRODUCTION LINE.