Type of Solder? High Tin% or Silver

[Mike90250]

the gold standard for solder is 63/37 Sn/Pb electronic solder. It is proven, and used in EVERY spacecrafts solar arrays. Changing the solder always has less optimum results than the 63/37 solder. For electrical conductivity, you have long strips of copper soldered over a wide area on each cell, the current density is quite low in the solder area, and therefore, the voltage drop is low.
If you deviate from 63/37, your results are lessened. The higher temps for silver bearing solder, dissolve the metal plating off the cells very quickly, and solder of no kind sticks to silicon......

[Guest]

What metals are you refering to.
The manufacture states the back surface field is aluminum
And the 3 bus bar of solar cell is aluminum/silver.

What alloy are you refering to and where on the solar cell. I just like to know so I have idea what metals you refering to.

[Sunking]

Sn = Tin
Pb = Lead

[Guest]

Sorry I was referring to the metal Mike is talking about

"dissolve the metal plating off the cells very quickly,"

There is no metal plating other than the Aluminum/Silver for the 3 busbar and the aluminum surface field of the back of the solar cell?
Im not to familiar of all the alloys in a solar cell.
Just lookn for enlightenment and knowledge of this matter.

[Mike90250]

Front and back sides of PV cells are plated with a 3 atom thick layer of aluminum. Then a special metal paste is applied to the cell, and it is cooked in a furnace to melt and bond the metal paste to the aluminum layer. The pasted layer is what you solder to, and it can / will dissolve into the molten solder if you are sloppy in making your tab connections.
The front side has a special "Finger" pattern pasted on, to shade the least amount of cell, but not be too resistive. The back side is usually all pasted, or 2 large stripes.

here's a couple articles on it

http://www.sciencedirect.com/science/article/pii/S1876610213013799

ftp://ftp.ecn.nl/pub/www/library/rep...05/rx05006.pdf

http://www.slideshare.net/mehulmatrix/metallization-techniques-for-high-efficiency-solar-cells

http://www.sungroper.asn.au/project/solar-panel.html

You are soldering to a special layered stack of nearly transparent metal (the light has to get thru the metal to get to the cell underneath,

You need to do your own research if you want to question sound advice. I can only point you to it, I can't make you believe.
Let google be your friend solar cell metallization solar cell soldering solar cell soldering techniques

[Guest]

Thanks bro. You know this more than me So its good I get sound advice. Otherwise I be pouring over information that I wouldnt get nothing out of. But seeing as you know I will be contributing some pretty kewl stuff and showing off some of my work.

[Guest]

Im having problems soldering with the Kester soldering.
Does anyone know what Heat I should set my Weller at to do this
I finally got around to testing kester on my solar cells.

Any help is appreciated.

[Guest]

Also is this a good enough Weller for the job
cus this is the one i have.

[Mike90250]

your spool of solder should have a spec on it, look that up, and find out the melt temperature, you iron should be at least 50F - 100F hotter. And soldering is a learned technique, with the best gear, and perfect conditions, a learner might take 3 weeks of daily practice to get it "good enough".

[Guest]

your spool of solder should have a spec on it, look that up, and find out the melt temperature, you iron should be at least 50F - 100F hotter. And soldering is a learned technique, with the best gear, and perfect conditions, a learner might take 3 weeks of daily practice to get it "good enough".

Okay Great! Thanks alot Mike.
I havnt practiced with Kester yet.

I just gave it a few goes this morning and things are working better. Its actually bonding this time. I dont know why I couldnt yesterday
Turning out much better now.

[Guest]

What kind of Tips do you recommend
Just say 1-12 the number of the Tip

[Guest]

I set it at 85F. I still have some inperfections. But alot of them are nice and straight.
Just wondering if the details need to be better. I never looked at a real solar panel up close before to compare how well im doing.
I wish I had reference to look at and see how I can improve or something.
its really hard to see, and the sun made it more shiney

I just wish I can get it consistant. And I think the needle type tip is not doing great. I think I need something with a flat base at the front of the tip perhaps.

[Guest]

Strange This guy is using Lead Free Silver solder no Flux for his mono solar cells

Is this okay. I know I was using Lead free solder and uses just as much heat as the Kester with Lead
heres his youtube

https://www.youtube.com/watch?v=evhikE0clNs

[Mike90250]

The best and easiest is old fashioned tin-lead solder Sn63 Pb37 Elastic, reliable, and banned. Hard to find now, but most of the lead free replacements require more heat and are much more expensive.
Tip You want a "screwdriver" style tip, same width as your tab ribbon. A bit of solder on the tip & tab and you should be able to solder the length of the cell in one pass and have it come out mirror flat. IF the cell is clean, fluxed, and the tab ribbon is pre-tinned (most are) The solder you add, is to improve thermal contact from the tip to the tab ribbon, and the tab ribbon transfers the heat to the cell which is sweat soldered. If you try to add solder to the cell-tab interface, you will dissolve the metal off the cell and ruin it most of the time.

[Guest]

in one pass and have it come out mirror flat.

Thats exactly what Im looking forward to. I have some flux pens, and sadly some pens come out gushing with flux all on the cell, These pens seem unreliable leaving cell looking dumb.

I also wear latex gloves when handling this.

I think Im going to get something heavy and cut my tabbing and set it under that to staighten itself out. I just hate the curls all the time with tabbing, thats very hard to control.

I bet that screwdriver tip will do the trick! Thanks