Cell assembly solder bond examination techniques for high volume production

The long-term reliability of high-concentration photovoltaic (PV) cell assemblies requires a high degree of confidence in the quality of each solder bond. Ultrasonic examination of thousands of such bonds has shown a very small number of poor bonds. Because the quality of each bond is so critical to long-term module reliability, it is believed that each cell assembly must be thoroughly examined. Standard ultrasonic techniques are slow and require a skilled operator. The use of multitransducer ultrasonic testing and the novel technique of infrared solder bond imaging are explored. Preliminary results indicate that both techniques can detect solder bond defects and that the infrared technique is highly amenable to full automation