What CATL claims about extreme cold
A sodium ion battery stores energy using sodium, a common and cheap element, instead of lithium, the metal used in most electric vehicle batteries sold today. CATL, the battery maker that builds it, calls its version Naxtra. CATL states that a Naxtra pack built for passenger vehicles retains 90% of its usable capacity at 40 degrees below zero. A separate report a year later confirmed the same figure without naming any car. CATL also states the pack keeps working in temperatures from 40 degrees below zero to 70 degrees above, and loses no meaningful power at 40 degrees below zero even with only 10% of its charge left.
What an ordinary battery does in the same cold
Battery University, an independent technical reference used across the battery industry, states that a typical lithium ion battery cannot be charged at all below freezing. A specialty cold rated lithium ion cell can charge down to 10 degrees below zero, but only at a reduced voltage that caps its capacity at about 80% of normal. At 30 degrees below zero, the fastest charge rate the reference finds safe would need more than 50 hours to fill the battery. BAIC, a separate manufacturer building its own sodium pack independent of CATL, states its pack still delivers 92% of its rated output at 20 degrees below zero and recharges in about 11 minutes using a fast charging rate.
Sodium ion batteries offer broad potential for extreme temperatures and energy storage applications.
Wu Kai, chief scientist at CATL. Source 2.
How many times it can be recharged
A charge cycle is one full charge and discharge of a battery. CATL states its sodium pack can complete over 10,000 cycles before it wears out.
CATL states over 10,000 cycles for its own sodium pack, source 1. Battery University states 2,000 and higher for lithium iron phosphate and 1,000 to 2,000 for nickel manganese cobalt, source 4. All 3 numbers plotted are the stated floor of an open range, not an exact count.
Show the numbers
| Sodium, CATL | 10,000 |
| Lithium iron phosphate | 2,000 |
| Nickel manganese cobalt | 1,000 |
Energy packed into each kilogram
Energy density measures how much energy a battery holds for each kilogram it weighs, in watt hours per kilogram. CATL states 175 watt hours per kilogram for its sodium cell, calling it the highest among sodium ion batteries worldwide. BAIC states over 170 watt hours per kilogram for its own, separate sodium cell.
CATL states 175 watt hours per kilogram for its own sodium cell, source 1. BAIC states over 170 watt hours per kilogram for its own, separate sodium cell, source 3. The lithium iron phosphate and nickel manganese cobalt figures are the top of the range Battery University states, source 4.
Show the numbers
| Sodium, CATL | 175 |
| Sodium, BAIC | 170 |
| Lithium iron phosphate | 120 |
| Nickel manganese cobalt | 220 |
What no source publishes yet
No source gives both a capacity in kilowatt hours and a driving range in kilometres for the same sodium pack. The only published capacity, 45 kilowatt hours, belongs to a sodium pack CATL built for light commercial vehicles, with no published range. The only published range, 500 kilometres, belongs to a separate passenger vehicle pack, with no published capacity. Wu Kai said in April 2026 that CATL aims to bring sodium on par with lithium iron phosphate on range within 3 years, meaning sodium has not yet matched lithium iron phosphate on range according to CATL itself, even though its energy density figure already exceeds the range Battery University states for lithium iron phosphate today.