Cooling 18650 cells for soldering?

Im new at this hobby.

Can 18650 cells be chilled in the freezer prior to soldering them, to minimize the destructiveness of soldering?

I know they must not be charged at a cold temperature.

Dont worry I wont try anything experimental without first consulting all of you masters of the artform.

I am still getting through all the FAQs, thanks!

I would think the drastic difference in temperatures of chilling and hot top would be more damaging. But I'm not a chemist, so not really sure.

Remember as a kid someone keeping AAs in the fridge to keep them fresh?

keeping cells in the fridge to keep them fresh, or from self discharging, is completely different from having cells that around 40F and applying 300F hot tip to the end. The thermal stresses being applied to the steel casing could potentially weaken 'something'.

Again, I'm not a chemist so I don't know what this would do to the electrolyte, or what would happen to the seems on the cell, or the effects that will happen to the CID if it's not evenly heated.

I personally would not risk it production cells. Using a few cells for testing purposes, perhaps.

But, that's my opinion. I'm sure others will have a different view point/explanation.

Doubt cooling help. Just make sure you have a proper iron. I have videos testing above btw ..

Thanks!

I. gotta start real small with the 8 or so used cells I have anyhow, might as well solder them. I have a good soldering station. I suspect the cells I have are low quality cause they came out of battery packs that stopped charging. They went out of cycle, were discharged to much for the charging circuits to recognize them or something. Will sort that out on my day off soon with my new volt meter.

If I build anything big Ill likely build a diy spot welder. The cheapest Ive seen is made from a microwave transformer and a timer circuit.

I thought in my studies that I learned that Lifepo4 cells are much safer than Lithium Ion ones. This is misinformation? If the cells are balanced to begin with, proper wire and fuses are used, with the right bms?

Supposedly I have a year or two before Ill have to replace my 12v 35Ah deep cycle gell based battery with somrthing, I have a lot of time to learn, design and prepare for this.

The recycling aspect is appealing as well as a reason to use all the 3D printer filament I have.

Yes LiFePO4's are safer than LiCo's (common cells used in most battery packs). They also fit anything designed for Lead Acid based systems (inverters, UPS, chargers, etc) so they can be an easy drop in replacement. But they do need a little extra circuitry to go along with that. They are still Lithium based and need the proper charge curve to full the potential from them.

For learning with the few cells I have there is also the connection methods of using magnets or modified battery holders with wires soldered to those connection points, aside from kits that do similar solderless packs. Funny to me that I didnt think of either of these things myself, all I could come up with was putting them in the freezer. For a Powerwall magnets would sure be expensive.

Thanks again.

I had my cells stored in my unheated shed at around 3C. One immediate concern was the condensation on the whole thing as I brought it into my warm work area. There was a lot of sizzling when soldering to wet metal, but it worked. Can't say if it's safer or not, but I prefer my batteries stay dry.

daromer said:

Doubt cooling help. Just make sure you have a proper iron. I have videos testing above btw ..

Click to expand...

i second daromer.

solder HOT and short - a powerful iron, min (!) 100 Watts (totally unsuitable for normal electronics) (the typical 50 watts regulated is NOT enough), and a solder time between 1 and 1.5 seconds, then a QUICK cooling with air flow.
and, if you can, avoid the new ROHS tin, and use old ones with PB, that is the BEST advice possible, because the process window of ROHS tin is much smaller.

There are 2 ways to minimize damage to the cell when soldering the cell:

1. Use a large powerful soldering iron(80W+) to solder quickly. That can be quite hard to do, but with experience, it gets simple, and can be done in 2 seconds.

2. Create a RSU with carbon electrodes and solder paste.
This is an idea I've recently tried, and it's absolutely insane how quickly it actually bonds the solder paste to the steel canister.
It's like a spot welder, but with the ability to connect copper directly to the cell in about 1 second!

What you can also do is just put a fan right besides the cells you solder. Helps with heat dissipation.

Please see my guide about this here:

https://xaeus.wordpress.com/2014/04...-cells-without-causing-any-thermal-damage-en/

The article was written specifically for such a case.

Overmind said:

Please see my guide about this here:

https://xaeus.wordpress.com/2014/04...-cells-without-causing-any-thermal-damage-en/

The article was written specifically for such a case.

Click to expand...

Here's a quote from the above blog ......

"Note: if your soldering iron takes quite a lot to heat up (30 sec +), remove its tip in favor of a thinner one. A 1mm wire tip will heat up significantly faster than a 2mm wire tip. Do not exaggerate though. If its too thin, it will melt."

I'm not sure if something has been lost in translation, but the above, and a fair bit of the other content inthat particular entry is complete nonsense, especially the bit about using a frying pan as a heatsink "as long as it's not to waxed"

Guys, you need to learn how to solder better! And not thinking of ways of masking the mistakes by coming up with weird ideas!!

First of all you have to just put enough heat in a tiny localized area then apply the solder (preferably with a rosin core) and voila you have a perfect solder. I find a small chisel tip works best. Very minimal heat generated and dissipated right away.




Now before someone chimes in and say that the above looks like a bad solder and it's a cold solder, I can tell you it's not. It's just a perfectly placed solder with minimum waste. If you want to see a bad cold solder, look below. That's a bad cold solder. THat's what happens when you use a cheapo 40W soldering iron that has no power and you try and try until you find that perfect bubble and think it's good. Well it's not, just prick it with your fingernail and it's off!






Or some of you have chosen the brute method and got the largest chisel point for an iron that is used in making stained glass windows. First of all that's completely unnecessary. It's a waste of solder and then you have to deal with the issue of heat. In this case you would generate a lot of heat to that part of the cell. So could be potentially unsafe, and can be avoided by getting the right tip. Save on your solder, I have a 1lbs roll for over 20 years and I've made a whole 7s60p pack (my first pack) on it and it still is fairly full.

I use an Ersa industrial soldering iron with 50W you is better than some China soldering iron with 100W or more. And in addition solder grease which is applied with ear stick goose thin, just wiped thin. And so I walk well on all cells whether Sony, LG, Panasonic or others.

Soldering time for a 60 cell package is about 10 minutes with 120 solder points. Time per cell about 2 seconds Contact + - 1 second.

Ltfett is a no-go, my friend.
Thats for the gutters, at most.

( Ltfett ist schlecht, das ist nur fr die Dachrinne)

And you may beat me, but the solders look like missing power of the solder iron. (at least some...)

I tried a 300watt iron at first for 'quick touch' but it was too heavy and tip crumbled rapidly.

Settled on Weller 100watt iron + Kester 24-6337-0027 Solder Roll, Core Size 66, 63/37 Alloy, 0.031" Diameter. Over 5,000 soldered and counting...

The worst mistake I saw was not soldering per-se but someone used the wrong kind of solder that corroded the batteries over time.

Cherry67 said:

Ltfett is a no-go, my friend.
Thats for the gutters, at most.

( Ltfett ist schlecht, das ist nur fr die Dachrinne)

And you may beat me, but the solders look like missing power of the solder iron. (at least some...)

Click to expand...

Indeed. Plumbing flux will eat the coating on the batteries and cause them to corrode. It contains Zinc Chloride. Even though the ammonia content should cause it to self neutralize, it will still remain slightly acidic. Also, the coating around the solder will be damaged.

Yep.

If the plated nickel layer of the cell is destroyed(like with sandpaper), then the zinc chloride will just eat the steel.