China has had production EVs with sodium ion batteries for 2 years. I wonder when scientists will invent Freedom sodium so I can buy one in America.
That is amazing! I have just started making sodium ion battery chargers in my free time.
The bad thing abouslt sodium ion is that traditional CC/CV charging is harsh on the cells. Optimally each cell had to be CV charged at around 97.5% of its voltage end and then slowly brought up to 100%. Apparently that is how you get the most life cycles per cell
Why bother with the last 2.5% at all?
Good question!
Sodium ion already had a reduced capacity (30% less at least than Lithium ion). And 2.5% of voltage is not 2.5% of capacity, something more like 3-4% (still small)
You could then just choose to use a configurable lithium ion IC, but almost all of those have an undervoltage lock out (safety shutoff) that is 2-2.5V that you would have to stay above. Sodium ion drops out at 1.5V, so I would again be losing a chunk of capacity. If I lost 30%-35% of capacity on an already reduced capacity cell compared to lithium ion, then battery life would be quite disappointing.
Do that rules out using a standard Lithium-ion charger.
If I am building a custom charger anyway (most non- embedded systems have custom chargers), then might as well put in all the features now and get 100% of the capacity. Cells usually also have a higher lifespan (double or more) by dropping that high CV charge voltage 0.1V or so and settling for lower capacity, but Sodium Ion lifespan is already 3000-5000 cycles compares to lithium’s 500-1000 (lithium ion and li-po, lithium iron phosphate is in the higher range) so might as well then use the full capacity.
Some people who are like “I bought 100% of my product so I shall use 100%”
at what price?
Can this technology be used to retrofit existing devices with batteries of higher energy-density, such as phones, laptops, and mobile game consoles? Or is it really only feasible/worthwhile for large capacity usage?
Good Lithium-ion batteries have around 350 Wh/kg, so if you retrofit your devices, you’d be cutting out almost half the capacity, so at the moment it’s not feasible yet.
Once the form factor is there and the loading voltage is the same (or the charging circuit can be replaced), I don’t see why it shouldn’t work
For high energy density lithium ion is still king.
There was a recent e-bike company claiming to use this sort of technology but they were full of shit.
As cool as it is I hope it doesn’t become the new hype words for investors.
