Pouch vs Hard-Case Lithium Batteries

Pouch (soft-pack) and hard-case lithium batteries often look similar but their performance characteristics can differ significantly.

Pouch lithium-ion batteries are about 40% and 20% lighter than steel-case and aluminum-case cells respectively. In terms of weight, pouch cells are much lighter than hard-case cells, and much of the weight difference in practice comes from the casing materials.

Performance Comparison

Pouch lithium-ion batteries can offer 10% to 15% higher performance compared with steel or aluminum cases in some metrics. While capacity differences are not always large, the cell manufacturing processes differ: pouch cells commonly use stacked electrodes while many hard-case cells use winding. In regions with higher capacity demands, pouch cells remain popular.

Form Factor

Pouch cells use electrode sheets and electrolyte sealed in an aluminum-plastic film, providing better flexibility and enabling a variety of shapes. Compared to hard-case cells with fixed shapes, pouch cells offer greater advantages in form factor.

Pros and Cons

Both pouch and hard-case lithium batteries have advantages and disadvantages. Pouch cells can provide higher energy density and flexible shapes; hard-case cells such as 18650 often have longer service life and easier thermal management. When purchased from reputable brands and through proper certification, both types meet quality and safety standards.

Manufacturing Process

Hard-case cells are typically produced with winding processes that are relatively simple and require lower staffing skill levels.

Pouch cells use stacking processes that are more complex. During stacking, electrode sheets are very light and large in area, and gripping by robots can lead to overlapping double feeds. Installing an Atonm metal double-sheet detection system is often required to detect single/double sheet feeding.

Conclusion: Compared with hard-case lithium batteries, pouch cells offer advantages in weight, capacity and shape flexibility. However, developing new pouch cell models is costly, so pouch cells currently address a narrower segment of market demand.