Free software for testing solar cells and modules

Today we've released the beta version of a free software application that measures the I-V curves of solar cells and extracts useful model parameters. There's more information here.

The background:

Over the past six years we've done a variety of testing of solar cells and module prototypes, often as part of an iterative design cycle on a client's concept. This provides useful data as we try out different ideas for interconnects, encapsulation, bypassing, and alignment for conventional or CPV modules, as well as test performance degradation after environmental exposure (per IEC61215, IEC62108, and so on).

Fitting I-V data to a model of cell performance can provide high-level efficiency, current, and voltage information, as well as the ability to extract parameters such as the series and shunt resistances and diode parameters, which can help diagnose the root cause of problems (for example, J02 can give you hints about recombination and process-related damage). And with more involved models, it's possible to look at the effects of shading, non-uniform illumination, and cell-to-cell variation.

Over the years, we found ourselves often putting together quick software applications for testing, data correction, and analysis. We recently looked back through this work and decided to build a simple new IV testing application from scratch, both for internal use and as something we could share with the community. There are certainly a number other cell testing applications out there, standalone or integrated into production tools, but we think ours provides a good set of basic features, some extensibility, and most importantly, is free, to remove another barrier and make it easy for startups, small groups, and students to more easily test their new ideas

If you try it out, let us know what you think!