sodium or lithium cells

[hrchonda]

is it time to buy sodium cells instead of lithium?

at a quick glance, cost wise sodium 220ah cells seem to be a little cheaper compared to lithium 280's. link i found below,

weight wise, while it would add up building big banks, especially with sodium cells having reduced capacity. its not a mind blowing difference.
220ah sodium 4.5kg per cell
280ah lithium 5.35KG per cell

PROS
sodium has that extra layer of safety with no flammable electrolyte
charging at low temps -30C
3C to 5C discharging
and ability to discharge to zero volts without damaging the battery

CONS
has a reduced cycle count
voltage range doesn't match current equipment well

whats everyones views? is there pros and cons i dont know about?

cheers

Alibaba.com

www.alibaba.com

 

[David in nh]

is it time to buy sodium cells instead of lithium?

at a quick glance, cost wise sodium 220ah cells seem to be a little cheaper compared to lithium 280's. link i found below,

weight wise, while it would add up building big banks, especially with sodium cells having reduced capacity. its not a mind blowing difference.
220ah sodium 4.5kg per cell
280ah lithium 5.35KG per cell

sodium has that extra layer of safety with no flammable electrolyte

whats everyones views? is there pros and cons i dont know about?

cheers

Alibaba.com

www.alibaba.com

did you look into any problems you may have with voltages ?

 

[gotbeans]

Sodium are brand new so no. For the average person it's not better unless you're unable to heat lifepo4

Sodium batteries will be great for humanity as a whole. I hope to see a lot of these multi square mile / square km fields of batteries start to use them as space isn't so much of a concern etc.
They lack a lot of rare metals used in lithium batteries... not just the lithium but other metals of several lithium type chemistries. So it's easier to gather materials.

Will give a good use for all of the desalination plants we'll inevitably need with the droughts everywhere.

But no I wouldn't use them as they currently are. It's the same cost for less capacity, why do that to yourself?
It maybe makes sense on multi-million dollar scale, and it'll make more sense in 5 years when they'll probably be cheaper.

 

[JäseH]

The voltage range and cycle life are problematic. But I expect we'll see substantial improvements in the next few years.

 

[gotbeans]

The voltage range and cycle life are problematic. But I expect we'll see substantial improvements in the next few years.

the voltage range is actually awesome because measuring their capacity left will be extremely easy
current devices just aren't built with that range in mind

 

[billvon]

is it time to buy sodium cells instead of lithium?

Nope. Voltage range isn't compatible with most inverters right now.

 

[OffGridForGood]

I bought two, a 12v and 24v x 100Ah factory Soduim pack - to try them out and see how they do.
So far they are working exactly like the LFP packs, with no noticable performance difference, however I have been using them only a short while so far. The low temperature aspect are my main interest.

Each of these packs were built with BT locked BMS's (I can't change the settings, but can see them, and individual cell voltages) so far all good.
For my set up, the voltage limits may not be too far beyond the Inverter range; I am running them on MPP1012 and MPP2724 models in mobile set up.
As others have noted, these are new products, likely improvements will be coming, I like how they work so far. I am sure we will begin to see more posts about them. Being heavier than LFP, they are unlikely a good EV option, but could be great stationary ESS, especially as cost reduces. Seem to solve some of the issues with Lithium sources.

The packs I have do not recommend -30C operating temps, they say -20C and on the upper limit far higher temps than LFP, spec sheet shows 55 to 60 C 131F = should be of interest instead of A/C for the guys in hot locale.
However even being able to run a battery in -10 to -15C is a big difference for me, than being limited to 0C as LFP are. If low temp operation is important it may be worth trying some out. If no-one buys any, we will not learn anything.

 

[squowse]

the voltage range is actually awesome because measuring their capacity left will be extremely easy
current devices just aren't built with that range in mind

Thats a very minor benefit of a problematically large voltage range. Whats the internal resistance like. Eg difference between resting voltage and charging/discharging voltage. That messes up judging SoC by voltage.

 

[zcskywire2]

is it time to buy sodium cells instead of lithium?

No.

There is not readily available gear that can use them properly due to their high working voltage range. Roughly 2v to 4v per cell.
Beyond that they are lower capacity and lower nominal voltage. This mens they hold a lot less energy. The sodium ion batteries you mention (Rebranded CY 220ah) have ~75% of the capacity of the 280ah lithium cells (682wh vs 896wh). Their discharge curve is also very linear meaning if you are not able to use their whole voltage range you loose a large amount of capacity. I have the CY 220s and could test how much this is if someone wants.

Further more most of the Pros listed are either misleading, or wrong.

Sodium cells can not charge at -30c, the best I've seen right now is -10c for the cy cells listed. And only 0.1c or less at that temperature. Most of the ones I've worked with or have datasheets for say do not charge below 0c

3c -5c discharging is real but not for the sodium cells you list (Rebranded CY 220ah cells). They can do only 1c continual discharge from 0-45c. The full datasheet is posted in the resources. Only special high discharge sodium ion 18650s can really do 3c-5c, namely the lifun ones, datasheets also in the resources

0V safe discharge. This is true but again misleading. Only fariadion cells advertise this. No other sodium cells manufacturer has confirmed or mentioned it. I would not believe it until it's confirmed.


So no I wouldn't go with sodium cells right now, there's just not any good reason to

 

[OffGridForGood]

Sodium cells can operate at far higher temps than LFP,
for those who want cells that don't need to also run A/C to maintain cooler temps this seems like a very good feature.
Sodium is one of the most abundant elements on earth.
As far as I know, the soduim cells do not have a combustible electrolyte and are less prone to thermal runaway (according to the ICC report).
Recycling of the end product may be easier based on some reports, I am not sure about this aspect, time will tell.

It is true that the voltage range for the Sodium cells is wider than for Lithium, however in my own experiments with low voltage (12 and 24v) this difference is not beyond the range for the inverters. At 48v it certainly becomes an issue, however this is not 'the battery's fault' it is simply the inverters were not designed to match this chemistry's voltage range, which means there is little obstacle to making an inverter that does use the full voltage range if there were a market for one.

 

[squowse]

Sodium cells can operate at far higher temps than LFP,
for those who want cells that don't need to also run A/C to maintain cooler temps this seems like a very good feature.
Sodium is one of the most abundant elements on earth.
As far as I know, the soduim cells do not have a combustible electrolyte and are less prone to thermal runaway (according to the ICC report).
Recycling of the end product may be easier based on some reports, I am not sure about this aspect, time will tell.

It is true that the voltage range for the Sodium cells is wider than for Lithium, however in my own experiments with low voltage (12 and 24v) this difference is not beyond the range for the inverters. At 48v it certainly becomes an issue, however this is not 'the battery's fault' it is simply the inverters were not designed to match this chemistry's voltage range, which means there is little obstacle to making an inverter that does use the full voltage range if there were a market for

Which 12V and 24V inverters have you been using that can tolerate the voltage range?

 

[OffGridForGood]

Which 12V and 24V inverters have you been using that can tolerate the voltage range?

12v - MPP1012
24v - MPP2724

The 24volt inverter can use pretty much the full Sodium voltage range but, this AIO can't charge the battery to the full voltage - 31v DC.
To top it off a bench top charger running from the inverter can top off the charge to full voltage.
The 'lost' capacity between the max inverter charge voltage and the max battery voltage is only a few percent, so not much concern for my use. I wonder if avoiding the max battery voltage will increase the battery cycle life as an unintended consequence.

 

[Hedges]

Nope. Voltage range isn't compatible with most inverters right now.

There is not readily available gear that can use them properly due to their high working voltage range. Roughly 2v to 4v per cell.
Beyond that they are lower capacity and lower nominal voltage. This mens they hold a lot less energy. The sodium ion batteries you mention (Rebranded CY 220ah) have ~75% of the capacity of the 280ah lithium cells (682wh vs 896wh). Their discharge curve is also very linear meaning if you are not able to use their whole voltage range you loose a large amount of capacity. I have the CY 220s and could test how much this is if someone wants.

That is a limitation for the nominally 48V inverters that might work from about 40V to 60V.
But high voltage inverters accept more like 100V to 400V. With limited current input, lower wattage at the lower voltage.

I think any of them (Sunny Boy Smart Energy, StorEdge, 3-phase 36kW SolArk, etc.) would probably accept them right now, just need a BMS which specifies voltage and current.

 

[OffGridForGood]

Seems to me, a bit of a "chicken and egg" problem:
1.The inverters available today do not support the full Sodium Battery voltage range so people don't buy Sodium batteries,
2.Because people don't buy Sodium batteries, inverter manufacturers don't develop new units that utilize the full voltage range available from Sodium.

- Sodium is far more abundant element but because people don't generally buy these cells, the cost per cell doesn't seem competitive to Lithium. The two Sodium batteries I purchased were not much difference in price from similar capacity Lithium packs. This lead me to think: if they can make the Sodium batteries at a similar price point, even with far lower economies of scale, these batteries would be far lower cost if their adoption into the market increased the production volume of the Sodium batteries.

Advantages of Sodium over LFP I have seen so far during use:
1. The cells can operate at temperatures below freezing. (no not -30c but they do run well down to -12c in my own use tests)
2. The cells can operate at higher temperatures without A/C than LFP. (maybe more important in TX, AZ, NM, So-Cal stationary storage use).
3. The basic element Sodium is far more abundant than Lithium, it may be less impactful on the environment to extract - not sure but seems likely.
4. Sodium cells seem to be less likely to support fires/thermal-run-away. - I am no expert, but this seems to be the case from what I have seen so far.

Disadvantages of Sodium vs LFP
1. Wider voltage range that is not well supported by current small capacity inverters, chargers etc. @Hedges point about larger inverters seems interesting for grid-scale storage. Especially if the cells can operate in un-conditioned storage space without energy-hogging A/C required.
2. The cells are heavier than LFP, making them less suitable for mobile uses.
3. If the cells do not see wide spread use, then even if they are "better" (environmentally, cost, safety, heat tollerance) their use may not take off.