Tesla's Chinese Battery Supplier CATL Unveils a Sodium-ion Battery, a Major Breakthrough for EVs

author: Eric Walz   

Chinese battery maker Contemporary Amperex Technology Co., Ltd. (CATL) on Thursday unveiled the company's first-generation sodium-ion battery, as well as a battery pack solution, which is able to integrate both sodium-ion cells and traditional lithium-ion cells in an electric vehicle's battery pack. 

Sodium-ion batteries are a new solution for the auto industry. CATL's first generation sodium-ion batteries have high-energy density, fast-charging capability, excellent thermal stability, as well as excellent low-temperature performance. 

The new battery chemistry can lead to the widespread adoption of EVs by reducing battery costs significantly. Sodium-ion batteries contain no lithium, cobalt or nickel. But perhaps the biggest advantage of sodium-ion batteries is the high natural abundance of inexpensive sodium.

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

CATL did not provide the costs per kWh to produce its new sodium-ion batteries, but said it has been working on the development of sodium-ion battery electrode materials for years.

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

One of the challenges facing CATL was that sodium ions have a larger volume and higher requirements for structural stability. This has become a bottleneck for the industrialization of sodium-ion batteries, according to CATL.

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

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 during cycling of sodium-ion batteries. 

The energy density of CATL's sodium-ion battery cell can achieve up to 160Wh/kg, and the battery can be charged to 80% in just 15 minutes at room temperature. CATL is targeting an energy density greater than 200Wh/kg for the next generation sodium-ion batteries.

The first generation of sodium-ion batteries can be used in climates with extremely low temperatures, which greatly degrades the performance of standard lithium-ion batteries. In freezing temperatures of -20°C, the sodium-ion battery has a capacity retention rate of more than 90% of its available power, according to CATL. A lithium ion battery exposed to this low temperature would not even function as the charged ions would stop moving. 

Sodium-ion batteries also can be used for mass scale energy storage systems.

Another innovation by CATL is its AB battery system solution, which can be used to mix and match sodium-ion batteries and lithium-ion batteries and integrate them into a single battery pack. Power output can be optimized using software for better performance.

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

Another benefit is that sodium-ion batteries can be built using existing manufacturing lines. Dr. Qisen Huang, deputy dean of the CATL Research Institute, said that sodium-ion battery manufacturing is compatible with standard lithium-ion battery production equipment, and the production lines can be rapidly switched to achieve a high-production capacity. 

CATL said it has already started its industrial deployment of sodium-ion batteries, and plans to form a basic industrial chain by 2023. CATL is also inviting its suppliers, customers and research institutions to jointly accelerate the development of sodium-ion batteries for the auto industry.

CATL is emerging as one of the world's leading supplies of batteries to the auto industry. The company also supplies batteries to Japan's Honda Motor Co, Volkswagen, Volvo and Mercedes-Benz. 

In June, Reuters reported that CATL is planning to build a major electric vehicle battery plant in Shanghai, as the company looks to become the world's biggest supplier of EV batteries.

CATL has been in talks with the Shanghai government about building its new battery factory. Locating its new factory in Shanghai will put it close to Tesla's own factory. However it's not clear when an agreement might be reached or when CATL hopes to have its new plant up and running. 

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

Last summer, CATL announced it's working on a new battery technology that incorporates the battery cells directly into an electric vehicle's chassis. 

The technology would increase the number of battery cells that can fit in a battery-powered vehicle, while also eliminating the large battery pack that houses the individual cell and modules. Integrating cells directly into an EVs body structure can help extend range by packing in more cells.

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.