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Rust protection
#1
Hi there, my first post here.

So, I am trying to build a battery pack for a project I have and got some used but still good 18650 cells. Since they were used in another battery pack before they had metal strips welded to the terminals, which leave annoying metal pieces when removed. Since I couldnt get them off with pliers I used a dremel for the last pieces, tho only on a few of them and only on the positive terminals. Coming back a day later I found that most of them started rusting on the terminals. I could get it off with a dremel, but they would start rusting again anyways...

Do you guys know something to put on there that would prevent rusting in the future?

Best regards
Alex
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#2
Don't use a dremel on cells. It removes the thin coating that prevents them from rusting. Instead, you can flush-cut wire cutters to snip them off or the flat side of your pliers to tap the small pieces down flat (this is what I do).

As for the actual question of fixing the damage already done, not sure...
Korishan and chuckp like this post
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#3
The only way to really keep the cells from rusting further is to drop solder on those spots. That is, to keep it conductive. If you want to protect them till later, use some electrical tape firmly pressed to help protect it from further rust. IMHO
chuckp likes this post
Proceed with caution. Knowledge is Power! Literally! Cool 
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#4
Like Mike and Korishan said, stop using the dremel, use small flush cutting snips and pool a little solder over the ends of the ones you've already done to stop them rusting.

Korishan likes this post
UK Southwest.

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14 X APS YC500i Micro Inverters.
28 X 40P 18650 cell packs/modules configured as 14S 80P.
Sofar Mass Energy ME3000SP AC coupled charger/inverter.
Still sourcing and processing cells for powerwall.
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#5
Try using a lanolin based spray ie one that leaves a non-conductive protective film on the surface.
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Running off solar, DIY & electronics fan :-)
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#6
Thanks for all the answers. I put some solder on them for now, but will I still be able to spot weld them with the solder?
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#7
you can, but the spot weld won't be as solid. Though, it will probably still be tough to pull off. Do a few tests on a dud cell first so you can get a feel for it. You only need a thin layer of solder, btw. Don't need to put a mound. Just make sure to use enough flux (non-acid, non-plumbing)
chuckp likes this post
Proceed with caution. Knowledge is Power! Literally! Cool 
Knowledge is Power; Absolute Knowledge is Absolutely Shocking!
Certified 18650 Cell Reclamation Technician

Please come join in general chit-chat and randomness at Discord Chat (channels: general, 3d-printing, linux&coding, 18650, humor, ...)
(this chat is not directly affiliated with SecondLifeStorage; VALID email req'd)
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#8
You cannot spot weld on top of solder. The melting point of solder is way off compare to the other metal.
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#9
What do people think of this:
- clean it up,
- spot weld new strip on,
- spray protective coat
Running off solar, DIY & electronics fan :-)
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#10
It would work i would say. Just beware you really should t spray anything on positive side since ut get into the went holes
chuckp and BatteryMooch like this post
The Ultimate DIY Solar and build place
YouTube / Forum system setup / My webpage  Diy Tech & Repairs

Current: 10kW Mpp Hybrid | 4kW PIP4048 | 2x PCM60x | 83kWh LiFePo4 | 10kWh 14s 18650 |  66*260W Poly
Upcoming: 14S 18650~30kWh | Automatic trip breakers, and alot more
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daromer (10-14-2019, 04:23 AM), Generic (10-15-2019, 04:06 AM), stevelectric (10-14-2019, 02:35 PM), OffGridInTheCity (10-13-2019, 04:25 PM), BarryG (10-13-2019, 04:20 AM), 100kwh-hunter (10-13-2019, 08:07 AM), juanjo57 (10-13-2019, 07:23 AM), mackoffgrid (10-13-2019, 08:16 AM), stok (10-15-2019, 10:38 AM), drnickriviera (10-13-2019, 04:19 PM), Blackbusa59 (10-13-2019, 07:53 PM), BatteryMooch (10-14-2019, 08:57 AM), Zennen (10-14-2019, 02:55 PM), emuland-metroman (10-14-2019, 07:50 AM), chuckp (10-14-2019, 09:43 PM), Jim Jr. (10-14-2019, 12:47 PM), mike (10-13-2019, 08:35 PM), Majorphill (10-13-2019, 12:08 AM), Korishan (10-14-2019, 01:20 AM), PAF (10-14-2019, 06:45 AM), jdeadman (10-14-2019, 02:36 AM), watts-on (10-13-2019, 11:12 AM), Geek (10-14-2019, 01:12 AM), Oz18650 (10-13-2019, 03:29 AM), gpn (10-13-2019, 03:48 AM), Redpacket (10-14-2019, 01:07 AM), Ibiza (10-14-2019, 04:25 AM), Bubba (10-14-2019, 12:12 PM), Alexander K. (10-16-2019, 10:32 AM)

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