Re: energy in UK

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:

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.

It depends a lot on the chemistry. The previous generation of NiCoMn Lithium cells were extremely volatile if they get damaged although have higher energy density. The latest generation of Iron based ones in the BYD blade implementation seem to be a lot more forgiving. This isn't a bad demo of the differences (bear in mind they are a battery vendor):
https://www.ufinebattery.com/blog/byd-blade-battery-comprehensive-guide/
In particular part 6 with the consequences of failure for each type.
Moves are afoot to double the energy density in the next generation if they can overcome the tricky problem of metallic dendrite growth under certain charging conditions.

At the moment lithium batteries are collections of quite small cells - roughly D-cell size.

Only in toys and a few older cars. You are hopelessly out of date. Prismatic or latest blade cells are now in vogue for new build.

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.

They do tend to go completely until it encounters an effective fire break. The jets of directed intense flame are something of a problem. Particularly in car collisions (tendency to relight also an issue) and vehicle recovery companies are unwilling to remove such fire damaged electric vehicles because of the risk of reignition.
The propagation between adjacent containers is predicated on windspeed less than 12mph and 6m spacing which is highly unlikely in the UK. They usually go for 3m here with pairs passive surface back to back.
The one I'm fighting is in a region with mean windspeed ~20mph and they want to use a 2m spacing based on some "interesting" fire risk analysis. UK land prices mean they want it as compact as possible.
Fire fighting plan consists of stand well back and let it burn. There is no water supply on site (actually there is - well pumped water on a 3" pipe 2 miles long). Fire code calls for multiple 0.6m fire hydrants.

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.

You obviously missed the Victorian Big Battery fire using Tesla modules where during installation they burnt out two full containers worth (infant mortality on precharge due to a coolant leak). Safety systems that fail dangerous are not good. I suspect rough handling poor installation practices were to blame as root cause.
https://www.energy-storage.news/investigation-confirms-cause-of-fire-at-teslas-victorian-big-battery-in-australia/
Moss Landing did nothing for the safety reputation of these systems.
--
Martin Brown