Sodium Ion battery technology - to be considered

[RFguy]

there is a new kid on the block, and I am using them commerciallyand if you are going to get a new battery, and going away from lead acid, then I beleive it is worth of contention.

 

I'd much rather have one of these  in my plane than any sort of Lithium chemstry

lots of good reasons, including, no DG... and is good for cranking current. and they are less likely to go bang, and have a lower temperature during any thermal runaway.

The twist is, their voltage range isnt quite as compatible with lead acid like LFP  (Lithium Iron Phosphate) . and they weigh a bit more for same effort as lithium. but they're cheap.

discharge curve looks like this  -  (per cell) 

which means in a lead acid 12V system, say 11V - 14.2V........with four cells in series, you are only going to be able to use about 55% of the total capacity 

but we dont tend to use capacity in our aircraft anyway. starting and a bit of run time in case of dead alternator. most can crank 8C to 20C, so a small battery can crank well.

You still need to shield them from high temps in an engine bay- all batteries should have a shiny (metal) shield around them to reflect the radiated heat away from them

this is not a bad treatment... anyway so much so I have changed over the family's  battery frigge camping kit to Sodium....

 

https://www.batterydesign.net/chemistry/sodium-ion-battery/

 

 

 

 

 

[kgwilson]

Sodium Ion batteries are starting to find their way in to Chinese EVs already. While their energy density is less than Lithium (currently NMC has the best) cost is around 30% of Lithium NMC or LFP. Sodium is plentiful being half of the chemical composition of salt (NaCl). The sea is full of it.

Edited Monday at 07:09 AM by kgwilson

[sfGnome]

Interesting trade off. Cheap, good cranking current, but a lot less time to find somewhere to land if your regulator or alternator carks it. Hmmm… So if you wanted to maintain your time to land, you’d need twice the overall capacity, meaning that the lower cost starts to not be so low. Still, interesting. 🤔 

[Bernie]

A mate of mine has just recently installed them in his motorhome.

When he finishes installing the solar panels he will be doing tests on the system... I'll know more when that happens.

Bernie.

[onetrack]

Sodium-ion technology batteries offer no substantial economic or major safety advantages in portable applications - especially when compared to lithium-iron-phosphate (LiFePO4) batteries.

The sodium atom has 4 times the mass of the lithium atom, and therefore energy density is far less than LiFePO4 - and it can't be improved, simply due to physics.

 

The sodium-ion battery has some application potential where weight and size are not critical issues. In a light aircraft, these issues are critical. 

Sodium-ion batteries have a lower life cycle than LiFePO4. As little as half the life cycle of LiFePO4, and two-thirds at best. 

The cost factor of sodium-ion batteries is not yet substantial, even though it is promised it will be much cheaper. 

 

The fire risk of LiFePO4 is already very low, and even when perforated they still don't "blow up", as the early, cheap consumer product, lithium-ion batteries did.

If they do get damaged, LiFePO4 will only smoulder heavily, they don't turn into a runaway spontaneously-combusting event.

Sodium-ion technology and research is still relatively new, I see no reason to rush into it for portable applications, because the overwhelming advantages are not there.

[Bernie]

Is there any restriction on either lipo4...or sodium batteries in light aircraft ?

Bernie..

[onetrack]

Yes, there are transport restrictions as regards transporting both LiFePO4 and sodium batteries in all aircraft, as they're classed as Dangerous Goods by transport regulations.

 

There is only one LiFePO4 battery certified for use in aircraft power or backup systems, it's the EarthX brand. No sodium batteries are yet certified for use in aircraft systems.

 

However, there are quite a number of pilots with light recreational aircraft who are using LiFePO4 batteries for power systems in their aircraft, with no reported problems at this point.

 

As always, the use of a LiFePO4 battery that has a robust and good quality Battery Management System (BMS) attached to it, is very important. 

[facthunter]

Pathfinders expose them selves to added risks.  Even BIG planes have had trouble with their Batteries. Wait TILL MORE IS KNOWN. Fire is not a good way to go.   Nev

[RFguy]

I was certainly not proposing Sodium  for propulsion in aircraft, we need another battery performance jump to make that work well.

 

However, Onetrack, - LIFEPO4  can and do go thermal runaway bad. they are not immune from it.

"If they do get damaged, LiFePO4 will only smoulder heavily, they don't turn into a runaway spontaneously-combusting event."

is not true.

I have seen it. But the cells were being abused, that's for sure , with overcharge.

Still, they are substantially less likely to go bang in the first place compared to their Lithium high performance cousins,

and I would not hesitate to have a good quality LIFEPO4  in my aircraft running the electronics. They do need to be shielded from radiative heat- must have shiny metal boxes around them to reflect the radiated heat from the engine. 

 

 

[onetrack]

I have read a very involved, technical, official research item (it was an American publication) a couple of years ago, that carried out destructive testing of both Li-ion and LiFePO4 batteries. Unfortunately, I can no longer find it.

However, the test results were clear, the LiFePO4 battery did not spontaneously combust, it merely smouldered - and at a much lower temperature. Admittedly, any smoke is bad news, and even worse news in an aircraft.

 

However, there are many destructive testing results available online, that show LiFePO4 is as inherently safe as you can get, as regards modern batteries - considering that high energy levels and plastics are also involved.

The Czechs below treat an LiFePO4 with ruthless attacks, most of which wouldn't happen in any normal use. The only flame that ends up being produced is the plastic burning.

 

 

[GolfWhiskeyHotel]

On 01/09/2025 at 7:37 PM, sfGnome said:

Interesting trade off. Cheap, good cranking current, but a lot less time to find somewhere to land if your regulator or alternator carks it. Hmmm… So if you wanted to maintain your time to land, you’d need twice the overall capacity, meaning that the lower cost starts to not be so low. Still, interesting. 🤔 

Interesting comment! MY aircraft does not give a shit if the alternator or reg/rec goes belly up. The engine will happily churn out full power for as long as I have fuel.....As do most others I believe. 

[sfGnome]

Fair enough. I was thinking of fuel injected aircraft where everything is reliant on a continuous supply of electrons.