Worried about cracking cells when I stick them to glass

[duffbeer911]

Hi all,
I'm just about to begin building my first DIY panel. (A small project for fun and educational purposes ... not intended for long term or money saving use and I know not as good as buying manufactured panels).

So I'm going to put the cells between two sheets of glass as is described in many of the online articles. I will have all the strings soldered together and lying face down on a piece of glass. Then put a blob of silicon on the back side of each cell. Then place the backing layer of glass on top and let it dry for a couple days. I'm worried that when I place the backing layer of glass on the cells they will crack....?
Alternately I could put a blob of silicon on the cells and then flip each string over to stick them down.

Any advice on which method would be best? Thanks

[SunEagle]

Hi all,
I'm just about to begin building my first DIY panel. (A small project for fun and educational purposes ... not intended for long term or money saving use and I know not as good as buying manufactured panels).

So I'm going to put the cells between two sheets of glass as is described in many of the online articles. I will have all the strings soldered together and lying face down on a piece of glass. Then put a blob of silicon on the back side of each cell. Then place the backing layer of glass on top and let it dry for a couple days. I'm worried that when I place the backing layer of glass on the cells they will crack....?
Alternately I could put a blob of silicon on the cells and then flip each string over to stick them down.

Any advice on which method would be best? Thanks

Seems to me that there is less of a chance of the cells breaking if they are already on the flat surface of the front piece of class when you put the second piece of glass on top. Sure there will be pressure points at each "blob" of silicon but the cells are already flat and should not defect from these pressure points.

On the flip side. If you put the cells to the back glass panel first there may be voids under the cells along the edges where the silicon did not get to. Then placing the front glass on top may cause the edges of the cells to "bend" slightly as they are pushed down by the top glass. This may cause cracking.

Since I have not built a DIY panel I may be totally wrong and there may not be any cracking problem either way. It could all come down to how flexible the cells are.

[green]

It is challenging to not crack the cells. The soldering on the front of the cells is flatter so you want to place that directly on the glass. Putting silicone on the back will buy you a little cushion for the lumpy soldering on the back of the cells.

[duffbeer911]

thanks for the fast replies. I will give it a try and hope not to crack any cells.

My plan was to put some spacers of a couple mm so that when the front piece is attached it is not actually touching the cells. I realise this is not ideal in terms of sealing the cell and also that there will be a bit more loss due to the layer of air .... but for this project I just want to make a panel which works and I can't justify the cost/time of encapsulating properly.

[Mike90250]

That's why the pros use sheets of EVA as a "compliant" glue & sealant.

Your silicon seal needs to be the electrical grade (acetone cure). The consumer grade smells of vinegar (acetic acid) since it is a moisture cure, and the residual acid will over time, destroy the thin cells.

[duffbeer911]

ok thanks for the tip on the silicone.

I've read a bit about EVA and resins but its pretty expensive and almost impossible to get out here so if I do decide on getting a pro set up then I'll get some manufactured panels imported. For now this is a bit of fun - and maybe I'll be able to charge my phone and some small things on days when the grid is down here