Battery

[Phil]

Whilst lithium is a very reactive metal, and unpleasant incidents and even fatalities have occurred, the technology has advanced significantly and I believe that the dangers of lithium batteries are now significantly overstated. Whilst care and vigilance are to be encouraged, some of the stories are akin to the reasons why, in the UK at least, use of mobile phones at petrol stations has been banned for over a decade. There is not one authenticated case of a mobile phone starting a petroleum fire, and no experiment, no matter how ridiculous, has ever succeeded in getting a normal mobile phone to ignite flammable vapours (you can't do it with a lit cigarette, either).

Meanwhile, lithium is the lightest metallic element, makes great batteries BECAUSE it is highly reactive under certain circumstances, and, most importantly, we are not going to run out of it for a very long time (unlike platinum and palladium; not every family in the world, even at present, will be able to have a hydrogen fuel cell car). Lithium battery technology is here to stay, folks, so get comfortable with it. Meanwhile, treat them with respect, remember that they are often made by an underpaid and poorly-educated workforce (because the West has priced labour out of competitiveness) and, if you don't know what the third terminal does, don't mess with it. Using the same logic, I regularly service and maintain mains-powered equipment with confidence, as well as having re-wired part of my house; but nothing would possess me to service the brakes on my car.

Phil M1GWZ



On 28 Jan 2014, at 23:47, Joseph Bento wrote:

> On 1/28/2014 6:45 AM, John Teller wrote:
>> Lithium ion cells are extraordinarily sensitive.  If you overcharge them, they will overheat, catch fire or explode.  If you discharge them past that magic number, they will undergo an irreversible chemical reaction such that if you try to recharge them they will overheat, catch fire or explode. If you discharge them too quickly, as in short them out when fully charged, they will overheat, catch fire or explode.  If you puncture a cell it is very likely to overheat, catch fire or explode.  Monotonous, isn't it?
>> 
>> Every cell that ends up in consumer service includes a fuse and a small IC whose only function is to permanently short out the cell once it falls below the minimum charge level. This isn't just lawyer stuff - see Boeing's recent experience with the 787 for an example of how hard it is to get this right, especially when the cells get really big.  Tesla, Nissan, GM et. al. have done an amazing job protecting their massive automotive lithium battery packs.  Each cell is equipped with its own cell minder which can communicate with the charger to provide all kinds of telemetry about the cell condition.  These packs are also centrally located not only for CG purposes, but also to shield them from collision damage.
>> 
> 
> It's so comforting that these virtual bombs are in everything. Equally comforting is that most are also manufactured in China.  It is not unheard of where one will spontaneously overheat, catch fire, or explode.  I believe most airlines now limit any spares you may carry either in carry-on or checked baggage.
> 
> Joe, N6DGY
> 
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