Out of our 61 large PV monocrystalline panels, large being over 1 meter x 1.6 meter, we have 2 that have been broken and shattered.
All PV panels use hardened tempered glass with the silicone cells and connections fused to the rear of the glass and then vacuum sealed with a membrane on the rear then sealed into a aluminium frame. PV panels produce DC, (direct current), and are connected in series to increase the voltage but the amperage is held to the lowest amperage rating of the connected PV panels string.
As you can see in the photos the glass just shatters.
No 1 Photo, ..........
The first is a cheapo KNIVE 250w, 1 meter x 1.6-meter, Mono, made in China, been on the static array over 12 years now. Failure due to faulty manufacturing on the rear film and the heat has buckled the glass and as it is hardened it has shattered. Been through one winter so far and no loss of electrical voltage but the amperage is dropping.
Eventually the static array will cease generating as the panels are series connected and the water ingress gets in and shorts the PV panel out. But for now, i will let it run and monitor.
The two photos below show this panel to be just one faulty cell from the 60 cells.
The below right is the back of the cell where an adhesion connection has problems. Probably caused by the rear sealing film not sticking correctly under vacuum and giving a poor electrical connection to the other cells.
No 2 Photo, ........
. This one is a SOLARWORLD 260w, 1 meter by 1.65 meters, Mono PV panel, and made in Germany. All parts were made in Germany under EEC regulations. And this a good reasonable quality panel.
It was hit by a flying stone sometime in early 2019, it is still producing electricity at good voltage and good amperage.
I have swapped this broken one from the 4.75KW roof array, for another good SOLARWORLD and now installed the broken one in the static array for close observation and monitoring.
Time will tell how these two broken PV panels behave.
My thanks to Christopher and also Peter for their assistance in the swap outs and re-installation.