Presentation Details
| Identifying Lifetime Limiting Defects in PV Modules - What Will Cause Failure First? Teresa M Barnes1, Dennice Roberts1, Martin Springer1, Jennifer Braid2, Rebecca Wai1, Dana Kern1. 1National Laboratory of the Rockies, Golden, CO, USA.2Sandia National Lab, Albuquerque, NM, USA |
Abstract
PV modules are expected to maintain high performance over decades outside in wildly varying conditions. The same modules are used in tropical, desert, temperate, hail-prone, high altitude, and cold climate. Most module performance warranties are 25-30 years long, and large PV systems that require financing are now expected to generate power for 35-40 years. Module warranty periods are often mistaken for lifetime predictions, but there is no agreed upon method to make a lifetime prediction for a module, especially considering the highly variable conditions modules endure around the world. The industry has learned how to effectively screen for known failure modes using standard tests. However, standards evolve slowly, and new module technologies are developed very quickly. We also have many different definitions of “lifetime” and different standards for failure. In this presentation we will discuss the merits of a module that could last for 50 years, how we define that lifetime, and how to identify weaknesses in new module technologies. We will also explore the idea of a lifetime-limiting defect, similar to a strength limiting flaw in a material, and how to identify which problems might cause modules to prematurely fail. We will also discuss which defects or weaknesses are easy to characterize, like cell cracks, and those, like low energy glass cracks, that are difficult to detect. Metastability makes it difficult to quantify the impact of some cell degradation mechniasms like UVID. Stealthy defects can be far more detrimental than some things that are relatively easy to see.
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No part of this publication may be reproduced, distributed, or transmitted in any form or by any means, including photocopying, recording, or other electronic or mechanical methods, without the prior written permission of the author.