Posted by: @transparent

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I too had spotted the Na-ion battery and matching inverters from Eleven in Cambridge.
it's good to see a British company designing something for the obvious gap in the market.

Note that their inverters can only be used with their own Na-ion battery.
It's not a generic approach. They need to be transferring data between their own BMS and the inverter across the CAN-bus to make the system work.

This is one of the few that splits the components: battery and inverter, but I also noted that they are not meant to be used except with each other. Eleven are clearly aiming for a battery pack voltage range around the lithium ones, so more cells must be used. This should obviate the issue with very thick cables. 

In terms of providing protection for power outage, these manual systems do not make much sense at this scale, specially as the competition is very mature. 

And I also did not find a proper diagram that includes the sodium batteries. 

I think vicron was one inverter brand that folks were trying to use with sodium, but I did not look much into it. 

Just a gentle reminder this thread is meant to be about LiFePO4 batteries, in particular whether then can of themselves cause fires and explosions.

I've just had a look at the latest online postings about the all electric narrow boat fire in the summer. The latest idea doing the rounds is that it might have been a VCE (vapour cloud explosion) where the battery produces gas (including hydrogen and methane from a LiFePO4 battery) which is then ignited. But (a) something has to make the battery produce the gas in the first place and (b) hydrogen itself burns with a pale blue flame, and the flames seen in the video of the explosion are saturated orange-yellow. Maybe the methane did that. Perhaps I need to do some experiments at the bottom of the garden. 

Yes, I think we need to move away from the Sodium alternatives.

I could mention a number of other technical issues in response to what @batpred has posted, but it's clear to me that LiFePO₄ is the dominant cell chemistry and likely to remain so for several more years.
It is still favoured for the great majority of home-based batteries and commercial (grid-tied) BESS.

Enray Power say they are using LFP batteries for a proposed BESS in North Devon, and it is to use a Stat-X aerosol fire-suppression system.

There is also a dedicated water reservoir for the proposed site, for use by the fire service if required.

The regional Fire & Rescue Service is usually regarded as a statutory Consultee by the Local Planning Authority throughout the UK.
But it's interesting to see how rarely they refer to the battery chemistry, or any potential hazards which might occur during maintenance work post-installation.

It seems as if there's a general form of wording which gets used in their responses to the LPA, irrespective of what cell chemistry and enclosures the Applicant actually proposes.
That doesn't help public-understanding,
and it deflects our gaze away from the absence of a risk-analysis matrix.

Nor am I sure if Applicants specify combustion-quenching systems merely to prevent fire issues being raised as an objection.
It's probably quicker and cheaper to propose a multi-layer fire prevention scheme than it is to have the Planning Application rejected.

Posted by: @transparent

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Yes, I think we need to move away from the Sodium alternatives.

 

Apart from relative immaturity and slightly larger per unit power stored, what are the issues which lead you to say this?

@cathoderay 

Yes, LPF batteries have a good safety track record. 

There isn't sufficient correlation between those exciting stories and early promotion of sodium batteries (that are clearly not ready for mass use).  

As for the "cloud explosions" and the VCE acronym, it must add to a sense of a heavily researched topic. 😀 

But perhaps it is merely that this special methane from LiFePO4 cells is rising to some human brains? 🤔 My first thought would be to suggest a fire barrier from hot topics.. A better solution would be for institutions to be upgraded to treat these anxieties (meditation zones lit by fossil gas, etc)? And then excess biomethane could also be recycled? Certainly fire hazards should not be walking around BESS sites.. 

@jamespa- myresponse is now here, as suggested by @batpred

@transparent 

Your post may fit better in the battery battle thread where I posted about Eleven and Victron?