[PLUG] Rebuilding laptop battery packs

Keith Lofstrom keithl at gate.kl-ic.com
Tue Dec 30 23:11:29 UTC 2014


On Tue, Dec 30, 2014 at 10:17:49AM -0800, Keith Lofstrom wrote:
> The big problems are (1) attaching the leads, and (2) teaching others
> how to to this, some of whom might prove to be litigious idiots.  
> Fast spot welders deposit very little heat beyond the weld, and
> idiots and their lawyers are a curable social disease.

On Tue, Dec 30, 2014 at 12:01:57PM -0800, Paul Mullen wrote:
> Battery vendors sometimes offer cell assembly services: you send them
> a drawing of how you want the specific cells arranged, they'll do the
> spot welding for you.  I expect there are quantity minimums for this.
> It would be worth investigating if you're really worried about
> scrapping cells and/or burning down the house.

Indeed, there are service companies that rebuild cordless tool
batteries, in onesies.  There may be similar companies that do
this for laptop batteries.  But ... 

I am a semi-competent hardware engineer, and I void warranties,
because I learn how other engineers think by taking their stuff
apart.  Same for the code I run - if I don't have the source,
flaws are harder to detect.  Most technology workers should
look inside their hardware and software.  Specialization is
for insects ... and pointy-haired bosses.
    
Regards scrapping and safety:  unlike alkalines, worn out Li Ion
cells contain valuable materials, plenty of recyclers.  I plan
to set up my workspace in the garage and do the tricky stuff away
from flammables, with the garage door open.  I worry more about
toxics than flames.

I would like to have a well-vented fume hood and do this in my
basement shop for such projects.  A friend has a full machine
shop and three fume-hood work benches in his basement.  He
also has lots of money, lots of insurance, and lots of
chemicals from the nasty regions of the periodic table.

I want learn about proper extinguishers for lithium fires.  I
presume the cells contain oxidizer.  I keep electronics-grade
Halon extinguishers near every room with working electronics.  I
hope Halon's endothermic reaction to flames helps with LiIon cells,
too.  It is crazy that they let these batteries on airplanes.

Keith

-- 
Keith Lofstrom          keithl at keithl.com



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