CATL and other battery manufacturers have been researching sodium-ion batteries for several years. Lithium-ion batteries are great but need relatively expensive raw materials such as lithium, nickel, or cobalt. They also do not perform well at low temperatures, as any EV owner who lives in a cold climate can attest.
Sodium-ion batteries use less expensive raw materials. Sodium itself is extremely abundant and cheap. But these batteries have lagged behind lithium-ion batteries because they have relatively low energy density — the amount of electrical energy that can be stored per unit of weight. Now CATL says its research has paid off with a new sodium-ion battery with an energy density of 160 Wh/kg. The company says it expects to boost that to 200 Wh/kg by the time large-scale commercial production begins in 2023.
To put energy density into perspective, the lithium-ion batteries used in the Tesla Model 3 have an energy density of about 260 Wh/kg, while the LFP battery cells Tesla uses come in the Model 3 Standard Range produced in China come in at around 200 Wh/kg. Elon Musk has hinted at batteries with 400 Wh/kg energy density in 3 to 4 years time, which could enable competitive commercial airplanes.
The company says, “Sodium ions … shuttle between the cathode and anode. However, compared with lithium ions, sodium ions have a larger volume and higher requirements regarding structural stability and the kinetic properties of materials. This has become a bottleneck for the industrialization of sodium-ion batteries.
“CATL has been dedicated to the research and development of sodium-ion battery electrode materials for many years. In terms of cathode materials, CATL has applied Prussian white material with a higher specific capacity and redesigned the bulk structure of the material by rearranging the electrons, which solved the worldwide problem of rapid capacity fading upon material cycling. In terms of anode materials, CATL has developed a hard carbon material that features a unique porous structure, which enables the abundant storage and fast movement of sodium ions, and also an outstanding cycle performance.”
So, what does all that mean to drivers? Simply this:
- Energy density of up to 160 Wh/kg with up to 200 Wh/kg expected in a few years.
- Fast charging up to 80% SOC in 15 minutes at room temperature.
- Excellent thermal stability.
- Excellent low temperature performance — at -20°C, the sodium-ion battery has a capacity retention rate of more than 90%.
- System integration efficiency of 80% (weight or volume of cells versus weight or volume of battery pack).
Costs And Hybrid Battery Packs
“Sodium-ion batteries are compatible and complementary with lithium ion batteries. Diversified technical routes are also an important guarantee for the long-term development of the industry,” Robin Zeng Yuqun, founder and chairman of CATL, said on Thursday, according to China Daily.
The cost of sodium-ion battery cells is expected to be competitive with LFP cells. According to Chinese media sources, we can expect the first generation cells to cost $77 per kWh. With volume production, that figure could drop to below $40 per kWh. The sodium battery cells can be manufactured using current cell production equipment, which will help keep costs down.
But that’s not the only good news. CATL says it has developed new battery management systems that will integrate lithium and sodium batteries in the same battery packs. That means manufacturers could create battery packs tailored to meet the needs of drivers in various climates — more sodium cells in Minneapolis, fewer of them in Mobile. More sodium cells also means cars could utilize more electricity from regenerative braking on cold days.
The company says, “In terms of battery system innovation, CATL has made another breakthrough in battery system integration and developed an AB battery system solution, which is to mix and match sodium-ion batteries and lithium-ion batteries in a certain proportion and integrate them into one battery system, and control the different battery systems through the BMS precision algorithm.
“The AB battery system solution can compensate for the current energy density shortage of the sodium-ion battery, and also expand its advantages of high power and performance in low temperatures. Thanks to this innovative structure system, application scenarios for the lithium-sodium battery system are expanded.”
In the tech world a few decades ago, improvements in the power of computer chips came at a dizzying pace. The question was no longer how many angels could dance on the head of a pin but how many transistors could fit on a tiny piece of silicon.
Today, advances in battery technology are happening with ever increasing speed. The batteries in use in 2030 will be much more advanced than anything available today. Your grandkids will roll their eyes and giggle when you tell them it used to take half an hour to charge an electric car. The future is right around the corner. We can’t wait!