encapsulation of solar cells

conntaxman
conntaxman Solar Expert Posts: 125 ✭✭✭✭✭
After reading some threads on the net and ONE person said that they use only 20 oz to do 36 cells. I have just started to encapsulata my 36 cells on glass 26x31 and it took 2 QT. I even tried to figure it out by sq.in./cups/oz, and it always came out about the same.[give or take some oz].
Has any one done this with LESS.?
I have another story about VACuum to take out all the air bobbles in the panels LOL.Im still laughing.
John

Comments

  • SirCaptain
    SirCaptain Registered Users Posts: 6
    Re: encapsulation of solar cells

    Hi John,

    I've been in the process of building my own solar panel at home myself. I have a 36 cell/54watt panel that I've made.

    After much research, watching videos on youtube, and taking parts of ideas from one person's diy panel, adding from another and another, I came up with a very simple, cost effect way to encapsulate the cells onto the clear glass/plexiglass.

    Im hoping, altruistically, that this idea catches on and potentially becomes a revolutionary change in how DIY panels are put together:

    I took 1 tube of Silicone II clear caulk...squirted the entire tube into a disposable small bucket. I then added about 1/2 cup of Mineral Spirits. Slowly mixing the two together, turns the very thick caulking into a soupy flowing mixture. In fact, if you get just the right consistency, you can literally paint it on with a cheap paintbrush, onto the back of the cells and the glass/plexiglass they're laying on!

    One tube is just enough to completely cover with a very thin coating on a 30"x36" size space. The next time I do this, I will reduce the actual size of the plexiglass for 36 cells down a bit (no space needed between cells), and then I'll use 2 tubes of the caulking. This should give quite a thick encapsulation over the cells.

    The nice thing about it, the Silicone II dries very clear. Yes, u will get some that flows underneath and around the edges of the cells. I cant say for sure yet, just how much of an impact this will have on wattage output, but I'd like to think not much, since its crystal clear.

    Good luck. Give it a try, and let me know what you think of this idea/process.

    SirCaptain
  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Re: encapsulation of solar cells

    Silicone II caulk is corrosive cure (acetic acid) and not recommended for electronics. the safe cure for electronics is acetone. (RTV 120)


    And all the Silicones are vapor permeable so water is going to get in there.
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  • SirCaptain
    SirCaptain Registered Users Posts: 6
    Re: encapsulation of solar cells

    Thanks Mike.

    Didnt realize that about the Silicone II. I'll check into the acetone. (RTV 120).

    After the silicone II cured, I then took a cut piece from a 4'x8' sheet of bathroom waterproof vinyl, and laid it on the back of the panel. I then siliconed it in place around all 4 edges, thus making it like a double barrier.

    So how long can I expect this DIY panel with the Silicone II to last and continue to produce power, before it corrodes my cells?

    Thanks,
    SirCaptain
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: encapsulation of solar cells

    Hopefully you can tell us from experience...

    I have not seen any of the common DIY technique panels last more than a few months in full weather.

    But the variations are so great (wood, plexi, glass, etc.)--It is probably unfair to generalize from the little I have seen/read about.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • conntaxman
    conntaxman Solar Expert Posts: 125 ✭✭✭✭✭
    Re: encapsulation of solar cells
    SirCaptain wrote: »
    Hi John,

    I've been in the process of building my own solar panel at home myself. I have a 36 cell/54watt panel that I've made.

    After much research, watching videos on youtube, and taking parts of ideas from one person's diy panel, adding from another and another, I came up with a very simple, cost effect way to encapsulate the cells onto the clear glass/plexiglass.

    Im hoping, altruistically, that this idea catches on and potentially becomes a revolutionary change in how DIY panels are put together:

    I took 1 tube of Silicone II clear caulk...squirted the entire tube into a disposable small bucket. I then added about 1/2 cup of Mineral Spirits. Slowly mixing the two together, turns the very thick caulking into a soupy flowing mixture. In fact, if you get just the right consistency, you can literally paint it on with a cheap paintbrush, onto the back of the cells and the glass/plexiglass they're laying on!

    One tube is just enough to completely cover with a very thin coating on a 30"x36" size space. The next time I do this, I will reduce the actual size of the plexiglass for 36 cells down a bit (no space needed between cells), and then I'll use 2 tubes of the caulking. This should give quite a thick encapsulation over the cells.

    The nice thing about it, the Silicone II dries very clear. Yes, u will get some that flows underneath and around the edges of the cells. I cant say for sure yet, just how much of an impact this will have on wattage output, but I'd like to think not much, since its crystal clear.

    Good luck. Give it a try, and let me know what you think of this idea/process.

    SirCaptain
    ]
    Hi SirCaptian/. I was thinking of how that would work and if you can thin our "silicone.I also Read on the internet that the ""First solar cell panels"" were made with encapsulated with Silicone.I have been reading all I can about the process. The best was were the person had used a auto cave. Im going to build one .Not too hard if you have atleast a small brain. ha ha ha . Its just a box with the ability to heat that space, and a vacuum bag. [you can buy a walmart] 1 vacuum gauge and 1 psi gauge,.an aircompressor that you can connect a hose/pipe to the "inlet" [that would be the vacuum]. Or get a vacuum pump.
    I was just looking at "Security window film'" I comes in CLEAR. and is sticky on one side.So even if you used that you can put that down and put the cell [blue] to the sticky side and then put another piece on top of that.
    The whole major part is mostly getting all the air out.I had done one 36 cell panel useing SURF Board resin. It worked very good except were I had an Air bubble. Were ever their was a air bubble it popped the resin,The temp outside was 22 deg, I think inside the air bubble was mositure and that froze and caused it to Pop the small hole,So I just filled the hole with sillicone and it work great 20 volts/3amps.
    But if i had vacuumed out the air bubbles it would have been 100 per cent good.pluse uv procted.
    see you guys, John
    well anyways its alot of fun.
    Oh well get it done to all the Na/ssss ers

    lol
  • jagec
    jagec Solar Expert Posts: 157 ✭✭
    Re: encapsulation of solar cells
    conntaxman wrote: »
    ]
    Hi SirCaptian/. I was thinking of how that would work and if you can thin our "silicone.I also Read on the internet that the ""First solar cell panels"" were made with encapsulated with Silicone.I have been reading all I can about the process. The best was were the person had used a auto cave. Im going to build one .Not too hard if you have atleast a small brain. ha ha ha . Its just a box with the ability to heat that space, and a vacuum bag. [you can buy a walmart] 1 vacuum gauge and 1 psi gauge,.an aircompressor that you can connect a hose/pipe to the "inlet" [that would be the vacuum]. Or get a vacuum pump.

    A few words of warning if you're going to build your own autoclave: Do ALL of the calculations first, and overbuild it like crazy. If you're using a resin that doesn't require very high temperatures or pressures for a reasonable cure cycle, great, but once you start getting up there in heat or temperature, there is a massive amount of stored energy in an autoclave, and any sort of structural failure could get interesting very quickly. If you're just going to be making tiny panels, it's easy to build something that can contain those forces, but DIY types tend to underestimate how quickly stored energy increases with larger volumes.

    This is a medical autoclave. A standard cycle runs at about 1-2 bar, which is a bit low for composites work.

    I'd stick to vacuum bagging and oven curing if I were you. Pressure does help a lot, but it's just too much hassle if you don't already have access to a commercial autoclave.
  • conntaxman
    conntaxman Solar Expert Posts: 125 ✭✭✭✭✭
    Re: encapsulation of solar cells

    Thank jagec. I'll keep that in mind. I'm only going to put in about 15 psi.and for the vacuum bag I don't know how many inches of mercury it will be.I think that you are talking about the PSI.
    The box will be about 48 in. long and about 36 in wide about 10 inches tall I am taking in concideration of the volume of the box, and do under stand about the pressuer that will be in the box.
    But tks for the input.It all helps, I also do think of being safe, well most of the time, ha ha ha .
    John
  • Urbandialect
    Urbandialect Solar Expert Posts: 107 ✭✭✭✭
    Re: encapsulation of solar cells

    Hmmmm, interesting.. I was going to use the Surf Board epoxy too, does it yellow much over time?
  • Vic
    Vic Solar Expert Posts: 3,208 ✭✭✭✭
    Re: encapsulation of solar cells

    Just for the record,

    Silicone I is the Acetic Acid based Silicone.

    Silicone II smells like it has Ammonia in it. It is reported being less corrosive than Sil I.

    Have Fun, Vic
    Off Grid - Two systems -- 4 SW+ 5548 Inverters, Surrette 4KS25 1280 AH X2@48V, 11.1 KW STC PV, 4X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  25 KVA Polyphase Kubota diesel,  Honda Eu6500isa,  Eu3000is-es, Eu2000,  Eu1000 gensets.  Thanks Wind-Sun for this great Forum.
  • Urbandialect
    Urbandialect Solar Expert Posts: 107 ✭✭✭✭
    Re: encapsulation of solar cells

    I know we can figure out how to encapsulate these Cell effectively if we put our heads together. I wonder if that Silicone II mixture worked for that guy? wish he would come back on and give us an update.
  • bmet
    bmet Solar Expert Posts: 630 ✭✭
    Re: encapsulation of solar cells

    do not use plexiglass
  • rollandelliott
    rollandelliott Solar Expert Posts: 834 ✭✭
    Re: encapsulation of solar cells

    "I know we can figure out how to encapsulate these Cell effectively if we put our heads together."

    sure you do it the same way the manufactured panels are made
    choice #1 the easiest for most diy
    Glass/cells/dow6100 silicone

    choice #2
    glass/eva/cells/eva/tedlar

    Only cost effect for a small panel under 80 watts or so

    for larger panels......

    you can get reject panels for 75 cents a watt, cheaper than you can make them.
  • bsolar
    bsolar Solar Expert Posts: 103 ✭✭✭
    Re: encapsulation of solar cells
    I know we can figure out how to encapsulate these Cell effectively if we put our heads together. I wonder if that Silicone II mixture worked for that guy? wish he would come back on and give us an update.

    here is how i did it and my 12 150W have been functioning flawlessly for several months now on the roof:

    -2 pieces of thin cheap glass 40X40 from doitbest.com (fits 36-6X6 cells perfectly)

    -build the cells face down on the first piece spacing evenly with 1" frame relief around the edge. a note: be good at soldering and dont leave raised globs everywhere.

    -silicone inbetween the cells in ONE direction only leaving the ends open do not get silicone on tabbing wire or the cells and use a bead just large enough to touch the edges of the cells when squished by the top glass (takes guessing until you get the feel for it).

    - set the top piece of glass on. put a fan aimed at it and let the silicone cure for about 3 days then force silicone in around the edges to seal the now laminated unit.

    other thoughts:
    "encapsulating" in silicone will seal heat into the cells - not good for performance, the 'double pane' glass system allows heat to radiate nicely but the thin glass is not very sturdy. I built a frame out of 1.5" aluminum angle with 2 mid-supports of 1" angle and 'glued the panel into that with silicone on all the frame contact surfaces .. all i can say is its working, and been through many full sun hot days here in Florida along with several hard downpours and even some small hail once .. no problems so far
    -plexiglass=no
    -any plastic or wood=no
    -as mentioned silicone is corrosive but mainly in its curing cycle, dont get it on the cells other than the edges and on none of the tab or solder connections, then after its structurally assembled the key is doing it so the stuff can cure fully internally before its sealed up on the outer edge .. viola
  • DeltaFox
    DeltaFox Solar Expert Posts: 27
    Re: encapsulation of solar cells
    "I know we can figure out how to encapsulate these Cell effectively if we put our heads together."

    sure you do it the same way the manufactured panels are made
    choice #1 the easiest for most diy
    Glass/cells/dow6100 silicone

    choice #2
    glass/eva/cells/eva/tedlar

    Only cost effect for a small panel under 80 watts or so

    for larger panels......

    you can get reject panels for 75 cents a watt, cheaper than you can make them.

    How about Glass/dow 6100/cells/dow6100= no air
  • bmet
    bmet Solar Expert Posts: 630 ✭✭
    Re: encapsulation of solar cells

    Do you have some measurements of Voc, Vmp, Imp? Have you found consistent numbers between individual panels?
    bsolar wrote: »
    here is how i did it and my 12 150W have been functioning flawlessly for several months now on the roof:

    -2 pieces of thin cheap glass 40X40 from doitbest.com (fits 36-6X6 cells perfectly)

    -build the cells face down on the first piece spacing evenly with 1" frame relief around the edge. a note: be good at soldering and dont leave raised globs everywhere.

    -silicone inbetween the cells in ONE direction only leaving the ends open do not get silicone on tabbing wire or the cells and use a bead just large enough to touch the edges of the cells when squished by the top glass (takes guessing until you get the feel for it).

    - set the top piece of glass on. put a fan aimed at it and let the silicone cure for about 3 days then force silicone in around the edges to seal the now laminated unit.

    other thoughts:
    "encapsulating" in silicone will seal heat into the cells - not good for performance, the 'double pane' glass system allows heat to radiate nicely but the thin glass is not very sturdy. I built a frame out of 1.5" aluminum angle with 2 mid-supports of 1" angle and 'glued the panel into that with silicone on all the frame contact surfaces .. all i can say is its working, and been through many full sun hot days here in Florida along with several hard downpours and even some small hail once .. no problems so far
    -plexiglass=no
    -any plastic or wood=no
    -as mentioned silicone is corrosive but mainly in its curing cycle, dont get it on the cells other than the edges and on none of the tab or solder connections, then after its structurally assembled the key is doing it so the stuff can cure fully internally before its sealed up on the outer edge .. viola
  • bsolar
    bsolar Solar Expert Posts: 103 ✭✭✭
    Re: encapsulation of solar cells
    bmet wrote: »
    Do you have some measurements of Voc, Vmp, Imp? Have you found consistent numbers between individual panels?

    Hi, and no i dont have exact figures, i figured in full midday sun about 7.5amps @ 21 volts open circuit test was about average though. I paralleled into 12v's so i wasnt too worried about balancing a system, but what i noticed was panels built together from the same stuff are about the same .. order a batch of cells from the same place, use the same tab wire and its pretty even .. get cells from different places or of a different type and there will be a wider variation for sure .. i built 2 monocrystalline 6" cell panels which are way different than the poly 6" and i built one from 72 'half cells' which are differnt to .. but myself, i didnt wind up with a 'dud' using all the same components, theyre pretty even among similar component construction.
    http://www.youtube.com/watch?v=mm-MjvwUu_A
  • rollandelliott
    rollandelliott Solar Expert Posts: 834 ✭✭
    Re: encapsulation of solar cells

    "How about Glass/dow 6100/cells/dow6100= no air "

    any liquid encapsulant will coat both sides of the cell when you pour it on
    dow 6100 is the thickness of motor oil, it's going to get into every crack.
  • Electricsuperduty
    Electricsuperduty Registered Users Posts: 8
    Re: encapsulation of solar cells
    "How about Glass/dow 6100/cells/dow6100= no air "

    any liquid encapsulant will coat both sides of the cell when you pour it on
    dow 6100 is the thickness of motor oil, it's going to get into every crack.

    Ya, but you ship the 6100 in used unsealed water bottles, it is contaminated with water cause it is not sealed properly, it's a waste of money. If your going to sell the 6100, fine, but ready up or ask Dow how to ship an opened container so when your buyer gets it he can use it- not throw it out after repeatedly bombarding you with emails about WTF.... :grr

    CAUTION TO ENCAPSULANT BUYERS- wether you buy it from an idividual or stores on Ebay, make sure it is sealed from the source container! if it is not sealed properly, prior to shipping and until you use it, air bubbles will form and you will ruin you solar panel. And I mean so many bubbles it looks like foam not encapsulant. And they just kept forming until it finally set up.
  • Electricsuperduty
    Electricsuperduty Registered Users Posts: 8
    Re: encapsulation of solar cells

    Step 1, Cover a piece of "pink board Insul" or styrfoam board in 3 mil poylethelyne, silicone doesnot stick to ethelyne. this should be 3" bigger than your glass. I taped my plastic tightly to the board "like a skin". now called the "work board". Place on sturdy firm table, level.

    Step 2, cut a piece of polyvinyl, silicone stick to this, and lay it on top of your work board, should be just a little bigger, not much.

    Step 3, cut a piece of 20Lb. white paper( found at hobby Lobby type stores)and lay it down on the vinyl..same size.

    Step4, lay assembled strings down on paper like you normally do blue side up, make a slit in the papaer with your exacto knife and pull the tab wire thru carefully.
    Now, this should look like a perfect solar panel laying on a sheet of paper.

    Step5, where you just pulled the tab wires thru under the paper, place a strip-one at each end- of polyethelyn between the paper aand tabs keeping them seperate. lay everything back down smoothly.

    Step6, use encapsulant. firstly between the string rows letting the paper absorb it, then cover the cells and spread out evenly, let set for a while-know you pot life time. lets air bubbles release.

    Step7, center glass over strings and gently place the glass ontop of the cells.
    you can press on the glass firmly to move bubbles out. NOW I have 10LB weights from my exercize machine (210 lbs.) i put a book down and 2 weights on the book, all over the glass until the pressure squeezes the air out. Yes I've put 210 lbs on a panel, now problems- evenly spread out. let setup.

    what is happening is the white paper is wicking or capulating the encapsulant around the back side of the cells. once set up, remove your weights and your encapsulated panel will pull free of the work board with a clear vinyl back sealed to it. trim off excess around glass edges and finish it however you like.

    You dont have to use the vinyl backer, I have one panel with just the white paper on the back, Ill seal it with another silicone layer and maybe some sheet vinyl??? Thanks to Dr. Richard Komp
  • Srilankaemc
    Srilankaemc Registered Users Posts: 2
    Re: encapsulation of solar cells

    Hi we are in Sri Lanka and did the silcone II work? we are having problems in finding the correct material to encapsulate the cells? Any other ideas or help require?
    SirCaptain wrote: »
    Hi John,

    I've been in the process of building my own solar panel at home myself. I have a 36 cell/54watt panel that I've made.

    After much research, watching videos on youtube, and taking parts of ideas from one person's diy panel, adding from another and another, I came up with a very simple, cost effect way to encapsulate the cells onto the clear glass/plexiglass.

    Im hoping, altruistically, that this idea catches on and potentially becomes a revolutionary change in how DIY panels are put together:

    I took 1 tube of Silicone II clear caulk...squirted the entire tube into a disposable small bucket. I then added about 1/2 cup of Mineral Spirits. Slowly mixing the two together, turns the very thick caulking into a soupy flowing mixture. In fact, if you get just the right consistency, you can literally paint it on with a cheap paintbrush, onto the back of the cells and the glass/plexiglass they're laying on!

    One tube is just enough to completely cover with a very thin coating on a 30"x36" size space. The next time I do this, I will reduce the actual size of the plexiglass for 36 cells down a bit (no space needed between cells), and then I'll use 2 tubes of the caulking. This should give quite a thick encapsulation over the cells.

    The nice thing about it, the Silicone II dries very clear. Yes, u will get some that flows underneath and around the edges of the cells. I cant say for sure yet, just how much of an impact this will have on wattage output, but I'd like to think not much, since its crystal clear.

    Good luck. Give it a try, and let me know what you think of this idea/process.

    SirCaptain
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: encapsulation of solar cells
    Hi we are in Sri Lanka and did the silcone II work? we are having problems in finding the correct material to encapsulate the cells? Any other ideas or help require?

    Welcome to the forum.

    Here's the best thing you can do: buy the solar panels already made.
    Prices are at their lowest now, and you can not build a panel as good as the commercial ones no matter what you do. Homemade will cost more, and have no warranty.
    Building your own is a waste of time, effort, and money.
  • Srilankaemc
    Srilankaemc Registered Users Posts: 2
    Re: encapsulation of solar cells

    Hi just one question did your encapsulate work using Silicone II as I am finding it a problem finding the products in Sri Lanka, saw the message for other person to buy already made panels, that really helps. Thanks?
    Can we use 100% Silicone with mineral spirits, as I did see something about damage to cells if we use Silicone II, any other help on this subject?