CHEAP NEW ORIGINAL 18650 21700 BATTERY CELLS, POUCHES AND PACKS
- Thread starter tumich
- Start date
mxer
1 kW
Can someone explain why it is dangerous to remove welded tabs from cells? What can happen?
Ptit_Philou
10 mW
Short circuit, fire, explosion, house burnt and... Death... 
Takemehome
1 kW
Just open the image link on first page in a new tabpianoman said:
Ptit_Philou
10 mW
"Just open the image link on first page in a new tab"
> Images links dead on first page...
> Images links dead on first page...
Ask NASA !mxer said:
Kin
10 kW
Here is a possibly more thorough answer:
A properly welded tab will have meaningful metallurgic bonds to the metal on the 18650 housing. This means you cannot remove them without damaging the bottom surface, at which point you can risk a puncture that lights the pack on fire (usually not so fast as the image shown, that was probably a specific destructive test.)
realistically, the majority of packs welded for laptops do not have sufficient strength to damage the 18650 shell, although my understanding is Tumich's packs are welded together with stronger bonds and are harder to remove. (because meant for higher current and more rigorous environments than laptop cells)
Ideally you can just cut the tabs you need to cut, and spot weld or solder to the nickel instead of trying to remove a well bonded nickel strip from the cell.
A properly welded tab will have meaningful metallurgic bonds to the metal on the 18650 housing. This means you cannot remove them without damaging the bottom surface, at which point you can risk a puncture that lights the pack on fire (usually not so fast as the image shown, that was probably a specific destructive test.)
realistically, the majority of packs welded for laptops do not have sufficient strength to damage the 18650 shell, although my understanding is Tumich's packs are welded together with stronger bonds and are harder to remove. (because meant for higher current and more rigorous environments than laptop cells)
Ideally you can just cut the tabs you need to cut, and spot weld or solder to the nickel instead of trying to remove a well bonded nickel strip from the cell.
mxer
1 kW
Thank you for the explanation. So the danger is puncturing the cell, Thank you..
I never knew these cells are so volatile, gawd I'm sticking with lipo for the minute, I've never had any issues what so ever in the 6 years daily I've been using them.
Not that I ever would!.
But I've seen and read, people using two bits of wood in a vice and a pin to remove puffy cells on lipo, just goes to show?
The more and more I read on 18650 the more and more I dislike the technology, but I can't help being drwn to the rewards and challenges of building my own pack. Perhaps it's the complicated challenging satisfaction of success? I do like the impossible and challenges in life
I never knew these cells are so volatile, gawd I'm sticking with lipo for the minute, I've never had any issues what so ever in the 6 years daily I've been using them.
Not that I ever would!.
But I've seen and read, people using two bits of wood in a vice and a pin to remove puffy cells on lipo, just goes to show?
The more and more I read on 18650 the more and more I dislike the technology, but I can't help being drwn to the rewards and challenges of building my own pack. Perhaps it's the complicated challenging satisfaction of success? I do like the impossible and challenges in life
Ptit_Philou
10 mW
Picture cames from NASA RoboSimian which exploded while charging...
https://www.wired.com/2016/10/samsung-isnt-one-lithium-ion-problems-just-ask-nasa/
Despite of this, good 18650 batteries are very reliable and you can find a lot of tutorials about building packs on this forum, on electricbike blog, or on YouTube...
I saved my Matra e-Mo /Eaton EV3 scooter and a ebike with my spot welder machine
https://www.wired.com/2016/10/samsung-isnt-one-lithium-ion-problems-just-ask-nasa/
Despite of this, good 18650 batteries are very reliable and you can find a lot of tutorials about building packs on this forum, on electricbike blog, or on YouTube...
I saved my Matra e-Mo /Eaton EV3 scooter and a ebike with my spot welder machine
Kin
10 kW
mxer said:
Uhm, I'm sorry - but FYI lipo is much more violatile than these cells are, simply due to lack of any casing, hence why I didn't think Ptit's response was very good. Edit FYI I see Ptit actually responded with a followup clarifying a bit. Sorry I missed that. 18650 cells require some background knowledge but are much harder to screw up than Lipos (the only exception might be if the fact that they're harder to screw up makes you think you *cant* screw them up, since that would be folly to think.))
Kin
10 kW
So, uhh, keep reading about 18650 cells, if you do want to make your own pack. If you feel they are more dangerous than lipo you might want to keep reading. I am not making my own pack again because once done I realized it was a PITA of work (especially starting from a base of used laptop cells and sorting/grading them painstakingly.)
Also it is a little jumbled to call the cell formats "18650" vs "LiPo.' Someone who knows more could clarify, but my understanding is LiPo just refers to the fact they're pouch cells (with polymer insulator.) 18650 is the 18mm diameter 65mm length metal casing. The insulator is different I believe in both cases, but the fact one is one or the other doesn't tell you so much. Some 18650s are terrible hazards, others are not.
Compare 1st gen lipo to modern lipo. 1st gen lipo is when things *really* lit on fire all the time. Still possible now, but less egregiously. And 18650 cells can be a variety of chemistry, not just LiCo. Soo err, yeah.
Also it is a little jumbled to call the cell formats "18650" vs "LiPo.' Someone who knows more could clarify, but my understanding is LiPo just refers to the fact they're pouch cells (with polymer insulator.) 18650 is the 18mm diameter 65mm length metal casing. The insulator is different I believe in both cases, but the fact one is one or the other doesn't tell you so much. Some 18650s are terrible hazards, others are not.
Compare 1st gen lipo to modern lipo. 1st gen lipo is when things *really* lit on fire all the time. Still possible now, but less egregiously. And 18650 cells can be a variety of chemistry, not just LiCo. Soo err, yeah.
Takemehome
1 kW
Ptit_Philou said:
You did not click on it because it works for me.
Do not mind the message Right click and open in new tab.
Ptit_Philou
10 mW
First, my whole nickname is "Ptit Philou"
(contraction of "Petit" that means "little" in french and "Philou" for "Philippe")
And I agree that LiPos are more fragile than 18650 format batteries : 18650 seem hard to "explode" and it may happens especially when charging or with short circuits.
Most electrical vehicules use 18650 batteries (Tesla cars, ebikes, scooters...) because it's reliable, cheap, and easy to pack with spot welder.
Just use good products from Panasonic/Sanyo, LG, or Samsung to avoid fake/dangerous batteries...
For information, if Adobe Flash Player plugin in Firefox is not up to date, this causes warning messages to appear, instead of images in forum...
(contraction of "Petit" that means "little" in french and "Philou" for "Philippe")
And I agree that LiPos are more fragile than 18650 format batteries : 18650 seem hard to "explode" and it may happens especially when charging or with short circuits.
Most electrical vehicules use 18650 batteries (Tesla cars, ebikes, scooters...) because it's reliable, cheap, and easy to pack with spot welder.
Just use good products from Panasonic/Sanyo, LG, or Samsung to avoid fake/dangerous batteries...
For information, if Adobe Flash Player plugin in Firefox is not up to date, this causes warning messages to appear, instead of images in forum...
Kin
10 kW
8 weeks delivery, as expected (6-8 weeks) but my cells did arrive beautifully packaged and in great condition . capacity untested so far, but will sometime.
. capacity untested so far, but will sometime.
bobmutch
100 W
can you ship to Canada?
Ptit_Philou
10 mW
Post 1 :
"Cells are located in Europe. No fees to EU countries.
SHIPPING TO WORLDWIDE BY COURIER AND BY POST."
"Cells are located in Europe. No fees to EU countries.
SHIPPING TO WORLDWIDE BY COURIER AND BY POST."
Takemehome
1 kW
Very nice pack but check the spot welds, there are misfires.
Check by sliding a small sheet of paper under the welds.
Otherwise, very nice pack for the price. Would buy again.
Check by sliding a small sheet of paper under the welds.
Otherwise, very nice pack for the price. Would buy again.
Ptit_Philou
10 mW
See post 1 : Tumich sells only packs right now...
jimwebo
1 W
Great seller gentlemen.
Totally reliable and communicative.
A few thousand cells bought it and zero problems.
Greetings.
Jim
Totally reliable and communicative.
A few thousand cells bought it and zero problems.
Greetings.
Jim
DVDRW
100 W
I'm excited tooqwerkus said:
sevillano1982
100 µW
- Joined
- Sep 16, 2017
- Messages
- 8
Hello friend.
I speak few english. Excuse me.
Have you cell lg 2850mah or panasonic 2900mah or alternative it?
Thank you much
I speak few english. Excuse me.
Have you cell lg 2850mah or panasonic 2900mah or alternative it?
Thank you much
