The Aptera Forum
I heard, but not read, that it is a resin( plastic) but ....if is different than what is used on auto outside lighting? I do not know.
Glass, like on.PV , would be too heavy and would not curve (conform) to the Aptera curves
What is CTE of cells mean?
As you must know....The body in a resin/fill sandwich-core composite resin.... It is not painted but vinyl wrap
Maybe some of this is helpful?
CTE is the Coefficient of Thermal Expansion of a material. Solar cells typically have very low CTE's. Composites have moderate CTE's based on the the resin and fiber used. As automotive applications go through one of the worst hot to cold temperature cycles in any industry, the adhesive used to glue the cells to the body and the resin going over the top of the cells has to be selected very carefully. Otherwise, the cells can begin to delaminate from the body, or the clear overcoat can begin to craze at the interface between the cell and the body. Soft materials have a high CTE and hard materials have a low CTE. The topcoat seems to have conflicting requirements - soft to provide some give, and hard to provide scratch resistance. I hope there is some PV industry tech they can leverage for this, and that they plan to temp cycle the solar array to verify it will hold up over time. It could get ugly very fast if they don't. These guys have done everything else right so far. I am sure they are on top of it.
I did read and hear that they have had the solar array, mimicking the vehicle’s array on the roof for year.
But that is all I know😔
And I doubt they were adding any protectant to that array’s surface, which could help with slowing degradation
I use clearner/ UV protectants on my home PV panels in solar zone 8 AZ but... they are not resin encapsulated
I assume that was a year on a roof in California. Good for verifying UV resistance, but hardly a challenging temperature cycle. It should be cycled -40C to +80C with time soaks at each extreme to allow the panel to come to temperature, 1000 cycles minimum.
Hopefully there is much more... just sharing what ai heard
Back in ~2009 when they had several Apter prototypes (2e) they just had a small solar array on the roof,
which mainly powered the interior venting