Any idea why the solar cells aren't packed more densely? It looks like there's a lot of wasted space on due to a square cell centered on a rectangular tile.
That's not really how it looks in the pictures on their site. It looks more like they are butted together with no overlap. Also, I'd think you'd want just as much overlap on the long side for weatherproofing. This does raise an interesting question; how are they weatherproofing this installation?
From when I was reading more about solar cells I recall there being something about the distance from the conductor (the two stripes visible equidistant from the midline of the cell) being a problem especially with monocrystalline cells, which these appear to be. I think this was more a problem for cells that had the conductor fixed to the back of the cell.
Google image search for monocrystalline solar cell and you'll see they are all square. I had a brief go at searching for anything to back up my claim but lost interest.
I might simply be that the silicon ingot they are cut from is cast round, see this[1] picture and it's less wasteful to cut a square with chamfered corners than to cut a rectangle, which would necessitate an ingot with an elliptical cross section, which would probably be harder to cast due to uneven cooling, maybe.
I'm not sure you can even make a mono crystalline ingot eliptical. The process heavily relies on spinning the ingot while pulling it out of a silicon puddle which results in the round shape.
I've had a few moments recently where I've thought "how can it be I haven't thought to look this up on YouTube before now", and here we are.
I found this[1] video that explains how to grow a monocrystalline silicon ingot that weighs 440 pounds, and you're right it is spun as it's extracted from molten silicon.