[RE-wrenches] 30-year old PV module

[Joel Davidson]

About half the spec sheets that I see list glass thickness, but only a few companies mention cell thickness unless it is in a press release. For example http://www.pv-tech.org/news/_a/ldk_solar_becomes_largest_wafer_producer_outlines_technology_roadmap/

Even if they do mention cell thickness, it may be for older modules or soon-to-be-released modules and not the modules that you buy.

Some people say that thinner cells are more flexible, that they will bend before they break wjhen encapsulated in the laminate. On the other hand thinner cells are more fragile and break more easily in handling. Micro-fractures look like canyons under a microscope and act like canyons to electron flow.




________________________________
From: benn kilburn <benn at daystarsolar.ca>
To: Wrenches <re-wrenches at lists.re-wrenches.org>
Sent: Mon, May 24, 2010 3:10:51 PM
Subject: Re: [RE-wrenches] 30-year old PV module

Great info Joel, thanks! 

are cell and glass thickness somehow encoded into a modules' spec sheet?  or do you have to dig deeper and hope to get a reply from a mfg?

benn

DayStar Renewable Energy Inc.  
benn at daystarsolar.ca
780-906-7807 
HAVE A SUNNY DAY


________________________________
From: joel.davidson at sbcglobal.net
To: re-wrenches at lists.re-wrenches.org
Date: Sat, 22 May 2010 16:42:36 -0700
Subject: Re: [RE-wrenches] 30-year old PV module


Hello Drake,
 
(silicon not silicone) Good question about thickness. I recently inspected a circa 1996 solar array with 300 micron thick, 6-inch round cells encapsulated behind 3 mm thick glass and found a few cracked cells and impact fractures. Today, some cells are 260 to 200 microns and even down to 180 to 160 microns thick. I think if the cells are handled properly, and the glass is 4 mm thick, and the module frame is strong enough to minimize twisting, and the modules are handled and installed with care, then cell breakage can be kept to a minimum. It's not how thin the cells are. It is how the cells and modules are encapsulated and handled.
 
Joel Davidson
----- Original Message ----- 
>From: Drake Chamberlin 
>To: RE-wrenches 
>Sent: Saturday, May 22, 2010 1:39 PM
>Subject: Re: [RE-wrenches] 30-year old PV module
>
>Thanks for the excellent article.  I have two of these old Arcos, and they still put out like new, even though one was (apparently) used in a concentrator, due to the fact that it came bronzed.  
>
>Do you think the newer modules, with thinner silicone, will last as long?
>
>
>
>At 10:53 AM 5/21/2010, you wrote:
>
>If your prospect asks how long do PV modules last, refer them to this article
>>http://www.greenbuildingadvisor.com/blogs/dept/musings/testing-thirty-year-old-photovoltaic-module Drake Chamberlin
>Athens Electric
>OH License 44810
>CO License 3773
>NABCEP TM  Certified PV Installer 
>Office - 740-448-7328
>Mobile - 740-856-9648 
>
>________________________________

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