In March 2025, SAMSUNG SDI Vietnam held the first shipment ceremony of 46-phi battery modules. The modules were produced using 46-phi cylindrical batteries manufactured at SAMSUNG SDI’s plant in Cheonan, and designed for micro mobility applications. 

[SAMSUNG SDI employees pose for a commemorative photo at the first shipment ceremony of 46-phi battery modules]

SAMSUNG SDI’s 46-phi cylindrical batteries, with a 46 mm diameter, are the standardized format that has been evolved from 18650 and 21700 cells. Unlike the previous cells, the height can be customized to meet customer demands, making it suitable for a wide range of applications, from electric vehicles to micro mobility solutions.

[SAMSUNG SDI’s 46-phi batteries can be customized to meet customer demands]

Cylindrical batteries are cost-effective, highly productive, and safe. Because the cell sizes are standardized, modules and packs can also adopt standardized designs..

However, conventional 18650 and 21700 cylindrical batteries have relatively low capacity per cell. As a result, when building modules and packs for EVs or micro mobility that requires high capacity, the number of cells in modules and packs increases significantly. This, in turn, leads to a greater number of components and higher process complexity when manufacturing modules and packs.

[Cylindrical batteries provide an advantage against thermal propagation in module and pack configurations.]

The 46-phi batteries build on the strengths of conventional cylindrical batteries while delivering higher capacity and greater volumetric energy density. As a result, the number of cells can be reduced to about one-sixth of the previous level in module and pack configuration. This reduction lowers the number of components and the entire process complexity, thereby enhancing cost competitiveness.

The 46-phi batteries are more than just a larger cylindrical cell. They feature a newly engineered internal structure that enhances performance and quality, along with advanced safety measures tailored to higher capacity.

Notably, 46-phi batteries are designed with a tabless structure. Whereas conventional cells require tabs on the anode and cathode to conduct current, the tabless structure uses the substrate itself as a tab. This improves not only performance such as high output and fast charging but also overall product quality.

[Electrons flow of the conventional tab structure and SAMSUNG SDI’s technology applied tabless structure]

From a safety perspective, SAMSUNG SDI has applied a new method utilizing laser welding. This technology connects internal cell components by laser-welding from the outside.

In general, welding is easier when joining a thick material with a thin one. In the case of battery cells, the internal components are thin while the external components are thick, so welding is usually done from the inside. However, this carries the risk of foreign particles entering the cell during the process. With the new technological method, SAMSUNG SDI prevents such contaminants from entering the cell, thereby enhancing safety.

Interest from major EV customers in 46-phi batteries, which offer strong competitiveness in modules and packs, continues to grow. SAMSUNG SDI plans to further develop and produce 46-phi batteries that deliver both high performance and cost competitiveness. The know-how gained through the 46-phi battery development will also be applied to premium cylindrical batteries, further enhancing the competitiveness of SAMSUNG SDI’s cylindrical portfolio.