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From: Bill Sloman <bill.sloman@ieee.org>
Newsgroups: sci.electronics.design
Subject: Re: energy in UK
Date: Fri, 18 Apr 2025 18:27:51 +1000
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On 18/04/2025 5:52 pm, John R Walliker wrote:
> 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 
>> battery 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.


Those individuals "cells" are almost certainly batteries of smaller 
cells, assembled into a neat rectangular package to ease the 
construction of large batteries. This is where on of John Larkin's X-ray 
machines would be useful. A hacksaw could be as informative, but it 
could get messy.

> 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

-- 
Bill Sloman, Sydney