Path: news.eternal-september.org!eternal-september.org!.POSTED!not-for-mail
From: John R Walliker <jrwalliker@gmail.com>
Newsgroups: sci.electronics.design
Subject: Re: energy in UK
Date: Fri, 18 Apr 2025 08:52:43 +0100
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On 18/04/2025 08:24, Bill Sloman wrote:
> On 18/04/2025 1:56 am, john larkin wrote:
>> On Thu, 17 Apr 2025 12:44:15 +0100, Martin Brown
>> <'''newspam'''@nonad.co.uk> wrote:
>>
>>> 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.
>>
>> A tiny dendrite puncturing a separator can start an ignition wave that
>> propagates in all directions at centimeters per second and ends in a
>> fireball fast. All a sensor might to is to tell people to RUN.
> 
> At the moment lithium batteries are collections of quite small cells - 
> roughly D-cell size.
> 
> A tiny dendrite puncturing a separator may start an ignition wave that 
> can propagate at centimeters per second, but only inside that D-cell - 
> and that would take a badly designed separator.
> 
> This sounds more like journalistic alarmism than any kind of peer- 
> reviewed study.
> 
>> Utility-scale batteries are huge and forklifts move pretty slow.
> 
> South Australia has had a grid scale battery for years and now has 
> several of them. They haven't caught on fire yet. A grid scale battery 
> in another state did catch on fire during construction, but mechanical 
> damage seems to have been the root cause, and the fire was pretty 
> localised - confined to one refrigerator sized block of cells. the 
> batter got built anyway.
> 
In the UK a lot of large domestic batteries use lithium iron phosphate
which is much less likely to produce a spectacular fire than lithium
ion.  The individual cells are the size of a large brick.

For example:
https://www.fogstar.co.uk/collections/lifepo4/products/eve-lifepo4-mb31-prismatic-cell-grade-a

https://cdn.shopify.com/s/files/1/1347/0997/files/MB31_..__compressed_1.pdf?v=1718013523

https://www.fogstar.co.uk/collections/solar-battery-storage/products/fogstar-energy-30kwh-48v-rack-battery-bundle

John