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Nickle versus aluminium versus copper for welding lithium battery cells

A

Andre

Jan 1, 1970
0
Dear all,

I would like to weld 2 lithium battery cells together using spot
welder. I understand that it's common using nickle tab on this purpose.
The nickle tab dimension is about 0.5cm x 3cm.

My question is: can I replace nickle with aluminium or copper or other
material since nickle cost me alot and it's hard to find them here? My
concern if I don't use nickle, they will have lower performance and/or
won't have a longer life.
Please advice.

Many thanks!

Andre <[email protected]>
 
S

Steve Dunbar

Jan 1, 1970
0
Andre said:
Dear all,

I would like to weld 2 lithium battery cells together using spot
welder. I understand that it's common using nickle tab on this purpose.
The nickle tab dimension is about 0.5cm x 3cm.

My question is: can I replace nickle with aluminium or copper or other
material since nickle cost me alot and it's hard to find them here?


Unitek <http://www.unitekequipment.com> has some application notes about
spot welding battery tabs. They say that the materials typically used for
tabs are either nickel or nickel-plated steel, .005" thick. Battery caps
are usually nickel-plated steel. I'm no expert, but I suspect it will be
difficult or impossible to get a good weld using copper or aluminum tabs.
 
J

John G

Jan 1, 1970
0
Steve Dunbar said:
Unitek <http://www.unitekequipment.com> has some application notes
about
spot welding battery tabs. They say that the materials typically used
for
tabs are either nickel or nickel-plated steel, .005" thick. Battery
caps
are usually nickel-plated steel. I'm no expert, but I suspect it will
be
difficult or impossible to get a good weld using copper or aluminum
tabs.

It will not be easy to choose what tab you use.
The tabs are usually already on the cells.
It would be very difficult to weld a tab on a complete cell.
 
A

Andre

Jan 1, 1970
0
Steve said:
Unitek <http://www.unitekequipment.com> has some application notes about
spot welding battery tabs. They say that the materials typically used for
tabs are either nickel or nickel-plated steel, .005" thick. Battery caps
are usually nickel-plated steel. I'm no expert, but I suspect it will be
difficult or impossible to get a good weld using copper or aluminum
tabs.

Steve, many thanks for your reply. I do some search on the web for 2
weeks and so far, I have to admit that _nobody_ weld 2 battery cells
together with copper or aluminium. Also can't find that anybody ever
ask this question, both on the mailinglist and newsgroup.

I asked once with a lithium battery cells salesgirl in China (and she
ask her engineer), the answer is: nickle should be used rather than
aluminium or copper, since nikcle's _impedance_ is lower (or higher?)
compared with copper or aluminium, that will effect the battery pack
performance. Anybody can confirm about this?
Again, many thanks!

Andre <[email protected]>
 
A

Andre

Jan 1, 1970
0
Dear John, many thanks for your reply. Yes, I found nickle strip in
every laptops battery pack I opened. What I try to do is un-weld the
battery cells and replace it with a brand-new battery cells, and then
weld the brand-new cells together. Sometime, in the process of
un-welding the old cells, the nickle strip damage and have to replaced.
Since I do this works many time, I need many nickle strip that cost me
alot. So I try to find other solution that cost me cheaper.
Andre <[email protected]>
 
E

Eric R Snow

Jan 1, 1970
0
tabs.

Steve, many thanks for your reply. I do some search on the web for 2
weeks and so far, I have to admit that _nobody_ weld 2 battery cells
together with copper or aluminium. Also can't find that anybody ever
ask this question, both on the mailinglist and newsgroup.

I asked once with a lithium battery cells salesgirl in China (and she
ask her engineer), the answer is: nickle should be used rather than
aluminium or copper, since nikcle's _impedance_ is lower (or higher?)
compared with copper or aluminium, that will effect the battery pack
performance. Anybody can confirm about this?
Again, many thanks!

Andre <[email protected]>
Greetings Andre,
The biggest problem with copper or aluminum compared with nickel is
the very low resistance of the copper and aluminum. The resistance is
virtually the same as the spot welder electrodes. So it is hard to
get the spot to weld before the electrodes get too hot. The higher
resistance of the nickel means it will get hot and melt well before
the copper electrodes. Aluminum has another problem besides the low
resistance and that is the thin oxide coating that forms on aluminum
almost instantly when a freshly cleaned surface is exposed to air.
This oxide coating makes it hard for other metals to stick to the
aluminum. When aluminum is welded by either the arc or flame process
the oxide coating is removed. When tig welded the weld is protected
from oxidation by inert gas and when gas welded with a flame flux is
used to remove the oxide coating and prevent forther oxidation.
Cheers,
Eric R Snow
 
A

Andre

Jan 1, 1970
0
Dear Eric,

Many thanks for your reply! This is a very good explanation about
copper and aluminium! I will try copper with my spot welder, if it's
can't weld good with the welder, I have no choice to use nickle :(

Thanks again, Eric!

Andre <[email protected]>
 
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