Why do bifacial modules need 2 mm glass?

As a result of the additional cost of very thin glass, most mass production bifacial modules being produced today are described as using 2 × 2.5 mm glass. More often, this means 3.2 mm on the front and 2 mm backsheet glass, states Weilharter – which brings down costs but in turn introduces its own issues.

What is a glass-glass module?

Glass-Glass module designs are an old technology that utilises a glass layer on the back of modules in place of traditional polymer backsheets. They were heavy and expensive allowing for the lighter polymer backsheets to gain the majority of the market share at the time.

What is the difference between tempered glass and glass-foil modules?

Compared to traditional glass-foil modules, which are about 18 kg, this is a 20% increase in weight. Although there is no standard on glass thickness, in general it is a more complex and expensive process to produce very thin, tempered glass. However, 2.5 mm glass thickness does allow for frameless designs, which can reduce costs dramatically.

What changes are incorporated in glass-glass modules?

Another major change that is also incorporated for glass-glass modules is swapping EVA for polyolefins as an encapsulant. This is due to the free radicals produced during the cross-linking lamination process of EVA. While traditional backsheets are somewhat permeable to the free radicals, the double-glass module is not.

Are bifacial double-glass modules a good choice?

There has been a noteable shift from the initial single-facial single-glass modules to bifacial double-glass modules. Double-glass modules, with their performance in the face of salt mist, high temperatures and high humidity, have won the market’s favour. However, this trend is not without its risks.

What are the benefits of double-glass solar panels?

Source : ITRPV Fig 16b Double-glass modules boast increased reliability, especially for utility scale PV projects. These include better resistance to higher temperatures, humidity and UV conditions and have better mechanical stability, reducing the risk of microcracks during installation and operation.