A Complete Overview of Lithium-Ion Battery Manufacturing: From Slurry Coating to Module Assembly

A Complete Overview of Lithium-Ion Battery Manufacturing: From Slurry Coating to Module Assembly

Lithium-ion batteries, known for their high energy density and long cycle life, are the 

backbone of modern energy storage systems—from smartphones to electric vehicles. 

Behind every high-performance cell lies a complex, precise, and multi-step manufacturing 

process. Let’s walk through the entire production chain, from slurry preparation to final 

module assembly.

1. Slurry Preparation and Electrode Coating

The process begins with slurry preparation. For the cathode, common active materials include 

lithium nickel cobalt manganese oxide (NCM) or lithium iron phosphate (LFP), while the anode 

typically uses graphite. These powders are mixed with conductive additives and binders in a solvent 

to form a homogeneous slurry.

This slurry is then coated onto a metal current collector—aluminum foil for cathodes, copper 

foil for anodes—using precision coating machines. The coated electrodes pass through a drying 

oven to evaporate the solvent, forming a solid electrode layer.

2. Calendering and Electrode Cutting

Next, the dried electrode sheets undergo calendering, where they are compressed between rollers. 

This increases electrode density and improves electrical contact. The electrodes are then cut into strips 

of specified widths for further processing.

3. Cell Stacking or Winding

The prepared electrodes are assembled into cell stacks using one of two methods: winding 

(commonly for cylindrical and pouch cells) or stacking (used in prismatic cells). A separator is 

placed between the anode and cathode layers to prevent short circuits while allowing ion transport.

4. Cell Assembly and Electrolyte Filling

The stacked or wound cell is inserted into a case (pouch, cylindrical, or prismatic shell), and an 

electrolyte—usually a lithium salt in an organic solvent—is injected. The cell is then sealed under 

vacuum to ensure airtight encapsulation.

5. Formation and Aging

After sealing, the cell undergoes formation, a critical step involving initial charge and discharge cycles 

under controlled conditions. This process helps develop a stable solid electrolyte interphase (SEI) layer 

on the anode, which is essential for battery longevity.

The cells are then aged in a controlled environment to stabilize their electrochemical characteristics 

and identify early defects.

6. Grading and Module Assembly

Each cell is tested for capacity, internal resistance, and voltage to ensure consistency. Cells with similar 

performance metrics are grouped and assembled into modules, which can then be integrated into 

battery packs with thermal management and a battery management system (BMS).

Conclusion

From nano-scale material control to precise electrical testing, every step in lithium-ion battery production affects the 

final product’s performance, safety, and cost. As the demand for higher energy and safer batteries grows, advanced 

manufacturing technologies and automation will continue to play a pivotal role in shaping the future of energy storage.