Application Background

Coated separators are critical materials in lithium-ion batteries and energy-storage cells. By applying a ceramic or functional coating onto the base film, they significantly improve cell safety, temperature behavior and cycle life. As battery and storage projects continue to expand worldwide, manufacturers are looking for coating lines with high-precision control and full process traceability. This project provides a compact, export-friendly control solution for separator coating machines, making it easy for OEMs to commission complete lines in different regions.

Solution Overview

• Main controller: Siemens PLC

• Process segment: Separator coating, drying and unwind/rewind tension control

• Project I/O configuration: 2RS-PN2 + 416DI + 416DO + 18AI

• Annual I/O usage: Approx. 300,000 points

Project Description

The system is built around a Siemens S7-1200 PLC with multiple Profinet remote I/O modules, forming a centralized control platform for the coating line. It collects signals from online coating thickness gauges, tension sensors, temperature and humidity probes, limit switches and drive status feedbacks:

• In the coating section, the PLC closes the loop between thickness feedback and line speed to control the coating-head servo, drives and metering pumps, ensuring uniform coating thickness.

• In the oven section, temperature and humidity channels are monitored and used to regulate the heating modules, keeping the drying profile stable and preventing over-baking or under-drying.

• In the unwind/rewind section, tension and roll-diameter data are used to achieve closed-loop tension control so the separator runs at high speed without wrinkles or edge deviation.

Multiple process recipes are stored in the controller, allowing quick switching of base-film width, coating system and line speed so one standardized control package can support different machine models and production lines.

Application Results

• Coating thickness is kept within tight tolerances, with a noticeable improvement in overall line yield.

• Key process parameters are continuously monitored and alarmed, reducing manual adjustment and unplanned downtime.

• Recipe management and historical data logging provide a solid foundation for customer audits and full quality traceability.

Application Advantages

• Compact control cabinet and dense I/O layout, ideal for both new installations and retrofit projects;

• Modular architecture allows easy expansion according to line length and process layout, minimizing re-engineering;

• Supports recipe management, data logging and remote diagnostics, simplifying after-sales service for exported lines;

• Standardized Siemens platform improves spare-part compatibility and reduces life-cycle costs for the entire coating line.