IRIS Real-time Hot Spot Detection 
IRIS™ is an innovative, in-line screening tool capable of identifying solar cells with shunt defects (hot spots). Customers can increase revenue and profit by discerning between cells that are safe for assembly into modules while discarding electrically similar cells that will overheat and degrade in the field. IRIS, exportable under ITAR, is designed for integration into the cell manufacturing line, and is running at a top-tier high volume manufacturing site. A stand-alone version (shown above) is also available.
The IRIS system integrates a deep infrared camera and proprietary image processing algorithms to assess the shunt characteristics of the cell under reverse bias conditions. The analysis is controlled through a user configurable recipe with control limits that disposition the cell into Pass, Fail (or Marginal) bins in 1-2 seconds. The results of this fast, in-line measurement have been shown to correlate well with conventional lengthy cell overheating measurements. Adding this unique high-speed inspection impacts the manufacturer’s top line by identifying cells that will operate within preset temperature limits and can therefore be shipped as product. It impacts the manufacturer’s bottom line by conclusively identifying cells prone to field failure that should be scrapped.
A PV manufacturer with stringent RSH sorting criteria may bin 10% or more of production as cells “at risk.” Tau’s experience is that approximately ½ of cells rejected on low RSH can be safely used in modules. Recapturing these cells for production results in $5M of additional annual cell revenue and $10M of additional module revenue per 50MW of output. Similarly, module manufacturers who are concerned with reliability guarantees can increase their long-term product performance by utilizing IRIS to inspect cells prior to module assembly.
