Dongwon Systems Begins Mass Production of Metal Cases for 21700 Type Cylindrical Batteries

SEOUL — Dongwon Systems, the packaging solutions developer wing of South Korea’s Dongwon Group, has started mass production of box-shaped metal cases for 21700 type batteries that have about 30 percent capacity in more than high performance 18650 type batteries.

While ordinary prismatic lithium-ion batteries are packaged in flexible, flexible polymer cases, cylindrical batteries are enclosed in metal boxes. Tube-shaped batteries have a lower energy capacity than their polymer-cased brethren, but metal batteries are easier to manage. When a cell in a battery pack fails, the defective cylindrical cell can be replaced with another while conventional battery packs must be replaced with another block.

Cylindrical batteries are becoming popular in the electric vehicle sector for their easy maintenance characteristics. Additionally, metal-cased batteries can withstand high internal pressures without deforming. A regular lithium-ion battery would swell and explode as pressure builds up inside the pack. Additionally, tube-shaped batteries can be produced at a much faster rate and cheaper than other prismatic batteries.

Dongwon Systems said 19 that the company has set up a manufacturing plant of 21700 boxes (21mm X 70mm) for secondary batteries and started sales in March 2022. The company has developed a technique to build the capacity of corrosion resistance of 21,700 battery boxes in January, after the company acquired battery box maker MKC in April 2021.

“We plan to upgrade our secondary battery box manufacturing capacity to prepare for the increased global demand by adding more production lines,” Dongwon Systems said in a statement on April 19.