Effect of oxidation on solar cell bus-bars
Subject: Effect Of Oxidation On Solar Cell Bus-Bars
Text: Does oxidation have a major effect on the performance of the solar cells? I've been trying to find some answers but no outcome yet.

I'll extend the question beyond either and talk about whole PV (Photovoltaic)  panels and the component parts. I'll talk mainly about crystalline silicon laminated panels as these are the industry standard and are known to be able to meet or exceed 25 year lifetimes when properly built.
Oxidation, and Oxygen, are major factors in PV panel lifetimes. (Chemists will tell you that you don't need oxygen for oxidation, and having potential differences makes this easier to occur, but in most cases Oxygen is a major part of PV cell and panel degradation.
A major degradation and failure source in PV panels can be stuff + water + Oxygen. If you can keep the water and/or the Oxygen out you will get little corrosion. You cant. A PV panel of multiple cells laminated between two sheets of low iron tempered glass using industry standard good quality EVA laminating material will have it's water vapor levels equalised with external ambient, typically within weeks to maybe a few months. For the rest of the 25 years you have to deal with water INSIDE the panel. Oxygen comes in faster.
PV cell materials (silicon wafer, on wafer current collectors, current collecting conductors, ...) WILL corrode and fail when exposed to liquid water and oxygen. An additional factor is that the industry standard EVA laminating material. EVA is used in the form of a clearish plastic film (also used in some glasshouse applications) that melts under temperature and pressure over a controlled time period and crosslinks and bonds the whole assembly together.
Have to do other stuff ... will complete later ...
Points:
LIQUID water against cells does damage. Water vapor much less so.
A bonding agent that binds with no voids and that has low water absorption works best. Water permeability is much much less important. Keeping LIQUID water off panel materials is a major aim.
Not all EVAs are created equal. Breakdown products can be a long term corrosion source.
Waterproof backsheets are needed BUT do not keep out water - only slow it down. Even iof backshet is perfect (eg float glass) water comes in sideways along the EVA seal. There are new matrials offerered to replace EVA. May be good BUT great care needed.
Specialised silicone rubbers may be superior to EVA+ glass. DFow Corning PV6100 is one such.
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