Application of Solidot IO-Link Bus I/O in Lithium Battery Wrapping Test Machine

In lithium battery production lines, the wrapping test machine serves as the final insulation safeguard before PACK assembly. If the film application shows bubbles, wrinkles, or dimensional deviations, the consequences range from yield loss and increased rework to defective cells entering the module stacking stage, creating safety hazards. For battery manufacturers, the yield stability and downtime duration of this process directly impact overall production costs.

This case study presents the application of Solidot IO-Link Bus I/O on a wrapping test machine, focusing on how it stabilizes process precision and yield through I/O communication, and how it assists maintenance to minimize downtime losses when equipment issues occur.

IP67 IO-Link Bus I/O Products Used in This Case

IOL7A-EC01B-8A 

(IO-Link master, EtherCAT protocol)

IOL7A-16CB-M12

(IO-Link Hub, 16-channel configurable digital I/O, PNP)

IOL7A-A8C-M12

(IO-Link Hub, 8-channel voltage/current input/output compatible)

I. Equipment and Process

The wrapping test machine is a dedicated insulation protection device on lithium battery production lines. Its core functions are to automatically apply insulating Mylar film to aluminum-shell cells, attach top insulation sheets, and perform online insulation withstand voltage testing and dimensional measurement.

The equipment process covers five consecutive steps:

II. I/O Communication Challenges

From the perspective of production line maintenance, the automation control faces two unavoidable pain points, corresponding to "yield" and "downtime".

Challenge 1: Wrapping and inspection precision directly determines yield, requiring high-speed signal transmission.

The unwinding tension of the film directly affects film flatness and folding quality, while dimensional measurement data determines pass/fail judgment. These are continuous analog signals requiring high acquisition precision and real-time performance. Any signal delay or interference can increase defect rates such as bubbles, wrinkles, or dimensional deviations. The system must ensure stable analog signal acquisition and precise output under high-cycle operation.

Challenge 2: Mixed digital and analog signals lead to slow fault localization and high maintenance costs.

The five stations are densely populated with discrete signals – cell positioning, film presence, cylinder action, suction cup negative pressure, probe lifting, reject removal – while continuous analog signals such as film unwinding tension, edge guide precision, proportional valve pressure, and dimensional measurements demand high accuracy. When signal anomalies occur, troubleshooting often requires checking each point individually, resulting in long downtime and high maintenance skill requirements.

III. Solidot IO-Link Bus I/O Solution

To address the above challenges, the Solidot IO-Link Bus I/O is adopted, connected to an Omron NX502-1600 PLC via EtherCAT.

Master layer:

IOL7A-EC01B-8A connects directly to NX502-1600 via EtherCAT, serving as the aggregation and forwarding hub for IO-Link communication, supporting real-time status diagnostics and remote parameter configuration.

Digital slaves:

IOL7A-16CB-M12 units are deployed near each workstation. With 16 configurable DI/DO channels, they uniformly connect proximity switches, photoelectric sensors, solenoid valves, and other devices, covering all discrete signal acquisition and actuator control from loading to unloading.

Analog slaves:

IOL7A-A8C-M12 units are deployed at the film unwinding and dimensional measurement stations. With 8 voltage/current input/output compatible channels, they acquire data from tension sensors and dimensional inspection systems, while outputting analog regulation commands to drive proportional valves and edge guide actuators, achieving closed-loop control of tension and lamination precision.

IV. Solidot IO-Link Bus I/O Overview

Solidot IO-Link Bus I/O currently offers two protection class series: IP67 (IOL7A metal housing and IOL7B plastic housing) and IP20 (IOL5, with optional dust cover). With diverse product forms, they can be flexibly selected according to site conditions. Compatible with mainstream bus protocols such as EtherCAT and PROFINET, they provide digital and analog signal acquisition solutions for demanding industrial applications including lithium battery, 3C, and automotive manufacturing.