A123 AMP20M1HD-A Battery pack kit

[999zip999]

Did the spark come from the bolt hole and bolt or from the top of pouch bottom of tap. Does it have some plastic around the top of cell - bottom of tap.

[whatever]

the spark came from right on the edge of the tab, there was a black mark there,
I think it must have shorted via the plastic/foil , it was the aluminium tab.

below shows pic of where the sparks occurred, black circle shows where the bolt head was located ( it overlapped onto the plastic), red dot shows where the sparks were. It seems only possible that the short was via the plastic ( I doubt there was anything metal on the table at the time it occurred) note the hole I've punched in the cell pictured is a different cell not the one that shorted

short.jpg (7.24 KiB) Viewed 362 times

I worked out a way to join the tabs together that seems to work quite well and very simple/quick process.
The cells I have , have very short tabs

tab1.jpg (11.61 KiB) Viewed 362 times

What I've done is fold one tab, slip the other tab into it and squash them together, that alone is not sufficient,
so I then used a tiny punch ( screwdriver in my case) to hold the copper/aluminium in place.

tab3.jpg (15.71 KiB) Viewed 362 times

It makes quite a secure joint for low amp applications ( in my case about 20amps max). Once the tabs are joined the cells need to be taped together as any movement between the cells will weaken the joint.
When I do the rest of the joints I'll use a bit of vaseline inside the joint, and some roofing silicone to keep moisture out.
I think it will last ok for my use, as long as the cells cant move against each other it should be ok.
I do need to pack between the tabs when I'm doing the punching which is a bit of work.
I've used some kapton tap to stop any shorting occuring and some water proof tape over the kapton.

[999zip999]

i would put some window foam with the adhesive on one side just above the top of the cell or and under and inbetween the taps the full width. Or something better than 7mm at home depot. maybe it melts or something, but what does Ping use. Look at a ping rebuild and see the foam.

[megacycle]

Hair clips, sticky tape, foam, goop, good choices, a couple of these state of the art cells could deliver over a kW into a short

[whatever]

not sure if this video has been mentioned, it shows very quick simple method to 'tin' the aluminium plate,
I have no idea what the paste he uses in the video, someone on here might know, it would solve the problem of how
to solder the aluminium tab
http://www.youtube.com/watch?v=W2xIKqry3ig

[Kin]

not sure if this video has been mentioned, it shows very quick simple method to 'tin' the aluminium plate,
I have no idea what the paste he uses in the video, someone on here might know, it would solve the problem of how
to solder the aluminium tab
http://www.youtube.com/watch?v=W2xIKqry3ig

I like it! I got that he says it's a special paste designed for soldering aluminum and having the solder included. I don't think that helps much though, because I checked that google translate gives you basically as much info.

When I saw the video [with sound off] I thought he was clamping glass plates to the cell. Do you think that's accurate? I was just wondering if metal wouldn't be better, or if the improvement isn't necessary. In thinking that out loud, I realized there's a much higher risk of shorting if you use metal, so I would avoid that.

[docnjoj]

When I saw the video [with sound off] I thought he was clamping glass plates to the cell. Do you think that's accurate? I was just wondering if metal wouldn't be better, or if the improvement isn't necessary. In thinking that out loud, I realized there's a much higher risk of shorting if you use metal, so I would avoid that.

The glass seems like a good idea. Some temperd glass can withstand force and a fair bit of heat. I to would love to know what the solder system was that he used. It could save us a lot of headaches.
otherDoc

[JRP3]

Maybe this stuff? http://www.solder-it.com/shop/item.aspx?itemid=89

[docnjoj]

Maybe this stuff? http://www.solder-it.com/shop/item.aspx?itemid=89

Don't know but that black paste stuff the guy in the film used was unknown to me. Solder-it has been around for a long time but I've never used any. A good test would be to try to solder heavy duty aluminum foil. I tried with scratching and flux and conventional solder and it was a bad fail!
otherDoc

[JRP3]

From his comment section, google translate:

The gray paste is a special product for aluminum in which the tin is already included.

This may be the so-tinned Aluableiter as the cells with any normal solder. be soldered to a Lötplatine.

Since the Verzinnvorgang runs quickly when the arrester is not hot cell input!

Solder-It Alu Paste No!

You can buy it in a few days in ebay.de

So I guess it's a new product?

[Kin]

JRP3, that's what we're unclear about. At the very least, he uses a different bottle than the solder-it alu paste. I made a comment on the page to see if he responds, meh.

[JRP3]

He did, as I quoted:

Solder-It Alu Paste No!

[Kin]

He did, as I quoted:

Solder-It Alu Paste No!

Oh! I did not notice his update, nor did I realize you were the person who first mentioned Alu Paste. Sorry. It is a pretty awkward way for him to phrase it, though, to add a "no!" in the front, but maybe it means no1. Or maybe it doesn't mean anyway. Eitherway, seems to be clearly that solder-it alu paste.

[JRP3]

I took it to be the opposite, "No, not Solder-it Alu paste".

[totinen]

I remember that I have read someone has succeeded in soldering aluminium under oil bath.

Actually, you can use normal motor oil or even cooking oil (like canola oil) when soldering aluminum. As was pointed out above the problem is that aluminum oxidizes within microseconds of exposure to the air and you want to keep this from happening. You need to immerse the aluminum in the oil and then clean it with a wire brush or something similar. Some people just keep brushing the aluminum with the soldering iron (or gun) tip while applying the solder. Of course, you MUST keep the aluminum, the soldering iron tip, and the solder within the layer of oil.

Now there is available solder with a special flux that can be used to solder aluminum. However, this is not always available. But, virtually everyone has some sort of suitable oil "handy" and that makes soldering aluminum relatively easy.

http://forums.qrz.com/showthread.php?174096-need-tips-for-aluminum-soldering

[docnjoj]

I remember that I have read someone has succeeded in soldering aluminium under oil bath.

I tried that too using WD40 but also a complete fail!
Any news agniusm?
otherDoc

[whatever]

i tried vegetable oil.....no good for me

[Bamboo]

I took it to be the opposite, "No, not Solder-it Alu paste".

Hi all,

looks like it's time for my first post German is my mother tongue, so I could help translating.
I think you're right, JRP3, it's not Solder-It he's using, but on that youtube link there is a new reply (in german) from someone owning a Austrian webshop for deco stuff, lighting etc ( http://www.hausschmuck.at ), who says if you want to buy this paste, you should send him a mail to info@hausschmuck.at to get a quote. Let me know your address and I'll ask him how much it'll cost you including shipping to US/CA. His reply was in german so I guess his english is useless, but if he owns a webshop he should have a paypal-account for quick payment IMO.
Edit: This appears to be his ebay-account, but he doesn't have anything up for sale at the moment:
http://www.ebay.de/sch/hausschmuck/m.ht ... ksid=p3692

That plastic container looks like you could tin a lot of tabs with it, you could buy 1 container and then share/redistribute it within NA among forum members.

Here is another Aluminium soldering paste (out of stock, though), it says it contains Silver particles, and needs to be heated to 200 C/ 392 F to melt. The solder is said to be stronger than the Aluminium itself. They also mention it can be used specifically for soldering Li-Ion battery tabs and once the tab is tinned, normal solder can be used. You just first have to break the oxide barrier on the aluminium (which prevents normal solder from sticking to aluminium) that would only melt when heated above 2050 C/ 3722 F (Aluminium itself has a melting point of 660 C/ 1220 F), so there's special chemicals in the solder to break it:

http://www.tmp-loettechnik.de/shop/prod ... issmetall/
General info on Aluminium soldering in german:
http://www.aluminium-loeten.de/Tipps_zum_loeten.htm

Cheers, Jens

P.S.: Thanks to everyone participating in this great forum, I learnt a lot here! A little bit of background about me: Am 35, built my first radio when i was 8, but compared to some of you guys I'll have to call myself a total noob (Edit: just found out that noob also means "not able or willing to learn", wouldn't say that about me - know the basics, but won't ever come close to some here on knowledge about electronics)
Didn't build a single ebike to date, but love electrified kickbikes (welded from old bikes, fitness devices, metal beds, etc., Bafangs in 20", 26" & 28", A123-packs), carving around with one of these = infinite grinning
Plan to build one from Bamboo poles, awesome material, very good at vibration dampening, light and also very strong, about the same as builder's steel. You might have seen Calfee's Bamboo Bikes, beauties IMO: http://www.calfeedesign.com/products/bamboo/

[whatever]

thanks so much bamboo for that info,
I've come across a guy in australia has found a way to solder copper to aluminium
the link is here
http://users.monash.edu.au/~ralphk/solder-aluminium.html
It may not be the ideal method for the lithium tabs but is very interesting he is using alumalloy brazing sticks ( expensive)

[whatever]

refering to bamboo link to aluminium / pot solder paste
some other links to same ( in english )
http://www.sunsetcrystals.com.au/solder ... metal.html
http://www.caswellplating.com.au/store/ ... pair-paste

[whatever]

even better heres the company website ( $8usd) per tube, hope it works
http://www.solder-it.com/shop/item.aspx?itemid=89
this article shows chemical constituents
http://www.solderit.com/ALP21MSDS.pdf

[Bamboo]

Thanks, whatever,

going through those links I'm pretty sure Solder-it is the same as the out-of-stock stuff from the german shop which was specifically meant for aluminium li-ion tabs. And that is probably not fundamentally different from what the guy in the youtube video is using. So 8 bucks to test it is probably better than getting a bigger box shipped from Europe (Austrian mail is especially expensive IMO).

Hm, I just posted in the used section I was interested in a 9C to build my first ebike instead of kickbikes all the time...but the more I read about these sweet pouch cells, the more I want to build finally a decent pack that will get me anywhere in the area where I currently have to take two heavy 90Wh/kg-18650-A123-packs. The pouch cells have about 144Wh/kg. 90WH/kg? Crap, I have Nicad batteries from Boeing emergency-power-back-up-systems, those have about 60 Wh/kg if I am not mistaken - and those are decades old...

[whatever]

I dont think solder-it is the same as in the youtube video, in that video its a dark colour material, and it just tins the tab,
I'm really not sure

[Bamboo]

Not sure either, but when I use normal solder to tin a copper plate or something it's essentially the same as if I was soldering a wire to the copperplate - when soldering I just have to use more solder to connect the wire to the plate and make up for what the wire is sucking up. IMHO when Solder-It is fine for soldering Aluminium plates it should be fine for tinning, too. Maybe just as in the video use some metal plate/foil to skim off excess solder.

Jm .02$

P.S.: Sent the guy a message via ebay, but no reply yet, I'll try by mail.

[docnjoj]

Just a hopeful bump, agniusm, to see if there are any words of promise on the horizon for your kits?
otherDoc