The key role of slitting machine in the manufacture of lithium battery pole pieces

The slitting machine plays a vital role in the manufacture of lithium battery pole pieces, and its core role is to accurately cut the wide pole pieces (positive or negative) after coating and rolling into narrow strips of design width to meet the process requirements of battery assembly (such as winding or lamination). The following are the key functions and technical points of the slitting machine:

1. Ensure the dimensional accuracy of the pole piece

• Width consistency: The slitting machine needs to cut the pole pieces to ±0.1mm or even higher precision (such as ±0.05mm) to avoid the dislocation of battery winding or lamination gap due to uneven width, which will affect the performance of the battery.

• Edge quality: Slitting must ensure that the edge is free of burrs and flanges, otherwise it may cause short circuit or lithium separation problems inside the battery.

2. Affect the integrity of the pole piece

• Prevents coating peeling: Improper tension control or tool wear during the slitting process can cause the active material to peel off from the current collector (copper/foil) and reduce battery capacity.

• Reduced dust generation: High-precision slitting can reduce metal particles or coating dust on the edge of the pole piece, avoiding the risk of battery self-discharge or short circuit.

3. Process adaptability

• Adapt to different materials: the hardness and brittleness of the positive electrode (aluminum foil + lithium iron phosphate / ternary material) and the negative electrode (copper foil + graphite/silicon carbon) are very different, and the slitting machine needs to adjust the tool type (such as round knife, ultrasonic knife) and parameters (tension, speed).

• Tab slitting: Some slitting machines need to complete the cutting of tabs synchronously, which requires multiple tools to work together to ensure the consistency of tab position and shape.

4. Production efficiency and cost control

• High-speed slitting: The speed of modern slitting machine can reach 60~100m/min, which needs to maintain stability at high speed and reduce downtime.

• Reduced scrap: Maximize material utilization and reduce production costs by optimizing the layout of the row knives, such as nesting.

5. Intelligence and quality control

• On-line inspection: integrated CCD vision system or laser width gauge to monitor the quality of slitting in real time and automatically reject defective products.

• Data traceability: record slitting parameters (tension, speed, tool status) to provide data support for process optimization.

Technological challenges and innovation directions

• Extremely thin foil slitting: ≤6μm copper/aluminum foil is easy to break, requiring ultra-precise tension control and air suspension support technology.

• Dry electrode slitting: Dry electrodes without binders are more brittle, and traditional slitting is easy to break, requiring the development of new cutting processes (such as laser slitting).

• Environmental requirements: Reduction of dust and metal chips in the slitting process, integration of dust removal and recovery systems is required.

summary

The slitting machine is the "precision tailor" in the manufacture of lithium battery pole pieces, and its performance directly determines the geometric quality of the pole pieces, the consistency and safety of the battery cells. With the development of batteries with high energy density and large size (such as 4680 cylindrical and blade batteries), slitting technology needs to continue to be upgraded in the direction of high precision, intelligence and flexibility.