On July 29, 2021 Contemporary Amperex Technology Co., Ltd. (CATL) unveiled its first-generation sodium-ion battery, together with its AB battery pack solution – which is able to integrate sodium-ion cells and lithium-ion cells into one pack.
CATL has started its industrial deployment of sodium-ion batteries, and plans to form a basic industrial chain by 2023.
The bottleneck of sodium-ion battery technology
The sodium-ion battery has a similar working principle to the lithium-ion battery. Sodium ions also 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.
Cathode and anode materials for CATL’s Sodium-ion batteries
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 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.
Features of CATL’s sodium-ion batteries
CATL says its first generation of sodium-ion batteries has the advantages of high-energy density, fast-charging capability, excellent thermal stability, great low-temperature performance and high-integration efficiency.
The energy density of CATL’s sodium-ion battery cell can achieve up to 160Wh/kg, and the battery can charge in 15 minutes to 80% SOC at room temperature. In a low-temperature environment of -20°C, the sodium-ion battery has a capacity retention rate of more than 90%, and its system integration efficiency can reach more than 80%. The first generation of sodium-ion batteries can be used in various transportation electrification scenarios, especially in regions with extremely low temperatures, where its outstanding advantages become obvious.
The next generation of sodium-ion batteries’ energy density development target is to exceed 200Wh/kg.
Integrated sodium-ion and lithium-ion batteries
CATL has also 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.
Dr. Qisen Huang, deputy dean of the CATL Research Institute, said that sodium-ion battery manufacturing is perfectly compatible with the lithium-ion battery production equipment and processes, and the production lines can be rapidly switched to achieve a high-production capacity.
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