Tesla's Battery Supplier CATL to Start Production of Sodium-ion EV Batteries Next Year

author: Eric Walz   

CATL's new sodium-ion batteries. The company said it will setup a production line by next year.

Improvements in electric vehicle battery chemistries over the years has resulted in EVs that are more powerful, deliver a longer range and charge more quickly. But new improvements in battery chemistries, including sodium-ion batteries (NIB), could extend range even further and eliminate the risk of fires associated with lithium-ion batteries, which recently resulted in the recent recall of all Chevy Bolt EVs produced by General Motors.

Chinese battery maker Contemporary Amperex Technology Co., Ltd. (CATL), which is a major supplier of batteries to automakers Tesla, Volkswagen and others, said it will put a sodium-ion battery production line into operation by next year. 

The company's plans were shared by Meng Xiangfeng, assistant to chairman of CATL, at a recent industrial conference in China focused on carbon neutrality, Chinese news outlet Gasgoo reported.

Mr. Meng said CATL has finally solved many technical problems associated with producing sodium-ion batteries, including the limitations on the raw material production. The challenge now is to increase production capacity and build a raw material supply chain.

CATL announced its first-generation sodium-ion battery in July.

Sodium-ion battery chemistry is similar to standard lithium-ion batteries with positive and negatively charged ions moving between the cathode and anode materials inside the battery. 

However, one of the challenges CATL faced is that sodium ions have a larger volume and higher requirements for structural stability. According to the company, this has become a bottleneck for the industrialization of sodium-ion batteries.

CATL's novel solution was to develop a hard carbon anode material with a porous structure. The stronger yet porous anode material enables the abundant storage and fast movement of sodium ions, as well as outstanding cycle performance, according to the company.

CATL also said it applied cathode material with a higher specific capacity and redesigned the bulk structure by rearranging the electrons, which solved the problem of rapid capacity loss when repeatedly cycling sodium-ion batteries. 

Sodium-ion batteries could become a viable solution for the auto industry as its transitions to electrification. CATL's first generation sodium-ion batteries have high-energy density, fast-charging capability, excellent thermal stability, as well as excellent low-temperature performance, according to the company. 

The new sodium-ion battery chemistry could lead to widespread adoption of EVs by reducing costs significantly, making electric vehicles more affordable. In addition, sodium-ion batteries contain no lithium, cobalt or nickel, which are the primary metals used in nickel-cobalt-aluminium (NCA), nickel-cobalt-manganese (NCM) and lithium iron phosphate (LFP) batteries. 

But perhaps the biggest advantage of sodium-ion batteries is the natural abundance of inexpensive sodium as a raw material. It can be extracted in mass quantities from seawater at low cost. 

The availability of inexpensive sodium could make commercial production of sodium-ion batteries much less than lithium-ion batteries today, which currently cost around $126 per kWh to produce, according to the latest data from Bloomberg New Energy Finance (BNEF), which tracks the battery industry.

CATL did not provide the costs per kWh to produce its new sodium-ion batteries. 

CATL says its sodium-ion battery offers an energy density of 160Wh/kg, currently the highest energy density in the world for this type of battery. At room temperature, the battery can be charged to 80% of its capacity within 15 minutes. 

Although an energy density of 160Wh/kg for CATL's sodium-ion battery is less than a lithium-ion battery's average energy density of 250-270 Wh/kg, CATL expects the energy density of its next-generation sodium-ion battery to exceed 200Wh/kg in the future as improvements are made.

Cold weather performance is even more impressive. CATL claims that in extreme temperatures of -20°C, the sodium-ion battery's capacity retention rate is more than 90%. A typical lithium ion battery would typically lose around 40% of available capacity at this temperature, representing a retention rate of just 60%.  

CATL also recently unveiled its AB battery system solution, which is able to mix and match sodium-ion batteries and lithium-ion batteries and integrate them together into a single battery pack. The two different types of battery cells can be monitored independently using battery management system (BMS) software.

For example, CATL's AB battery software can compensate for the lower energy-density of sodium-ion batteries, while taking advantage of the higher power and performance of newer lithium-ion or silicon-ion batteries in extremely cold temperatures. 

CATL also aims to rapidly expand its partnership with Tesla and become its biggest battery supplier globally. The company is aiming to supply half of the battery cells Tesla uses for its electric vehicles and energy storage systems, a senior source at the Chinese company told Reuters in June. 

Last year, CATL said its ready to build an EV battery with an expected lifespan of 1.2 million miles or 16 years before it needs replacement.

Eric Walz

Originally hailing from New Jersey, Eric is a automotive & technology reporter covering the high-tech industry here in Silicon Valley. He has over 15 years of automotive experience and a bachelors degree in computer science. These skills, combined with technical writing and news reporting, allows him to fully understand and identify new and innovative technologies in the auto industry and beyond. He has worked at Uber on self-driving cars and as a technical writer, helping people to understand and work with technology.