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From: Martin Brown <'''newspam'''@nonad.co.uk>
Newsgroups: sci.electronics.design
Subject: Re: energy in UK
Date: Thu, 17 Apr 2025 12:44:15 +0100
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On 16/04/2025 15:59, Bill Sloman wrote:
> On 16/04/2025 8:39 pm, Martin Brown wrote:
>> On 16/04/2025 00:17, john larkin wrote:
>>> On Tue, 15 Apr 2025 21:04:37 +0100, Martin Brown >> 
>>> <'''newspam'''@nonad.co.uk> wrote:
> 
> <snip>
> 
>> The big snag with Lithium batteries is their nasty tendency to catch 
>> fire spectacularly.
> 
> 
> You can design the battery monitoring circuitry to prevent them doing it 
> spontaneously. Electric bikes and the like may not be big enough to 
> justify the expense, but electric cars and domestic solar panel back-up 
> batteries certainly are.

I'm less convinced of that than you are. I think you can pretty well 
stop thermal runaway but only iff the sensors are done properly.

I personally know a family who have had such domestic battery systems 
installed which failed within a week of installation. They woke up to a 
popping sound and by the time they had got outside the house was already 
well alight. House was totally destroyed when the fire brigade arrived 
roof timbers failed very quickly in the fierce lithium fuelled fire.

I known perhaps 20-30 folk with domestic battery installations (some 
with more than one). That is quite a high percentage failure rate. They 
don't make the news any more unlike gas explosions which usually do.

Manufacturing defects, wiring harness faults, rough handling in transit 
and installer errors all multiply the risk. If they do survive the first 
month in service then more than likely all will be well.

> Any event that physically damages the battery can also set it on fire if 
> you are unlucky enough. The newspapers are great at reporting lithium 
> battery fires, and much less good at reporting the stupidity that lit them.

They are causing a lot of trouble with eToys being thrown away into 
general waste and then exploding either in the garbage truck waste 
crusher or later at the waste handling facility. The chemistry is pretty 
volatile and inclined to go pop at the slightest provocation.

eCigs are particularly problematic in this respect as fire starters.

>> A guy at nearby Newcastle University is an expert on such incidents - 
>> there isn't any good way to put such fires out either.
> 
> Too true, but they shouldn't happen in the first place.

It is a serious problem with any energy dense material that contains all 
of the ingredients needed for a very energetic reaction. To store 1kJ of 
energy in a rechargeable lithium cell the total chemical energy is 
roughly 7kJ (slightly more if the casing itself is flammable plastic).

-- 
Martin Brown