In-Line Testing Solutions for EV Lithium Battery Production

Designed to help avoid scrap and rework, improve quality, and save money

Published: Monday, January 31, 2022 - 12:59

(Marposs: Auburn Hills, MI) -- Marposs, with more than 60 years’ experience in developing solutions for quality control during the production process, has announced its solutions for monitoring the roll-to-roll (R2R) production process of electrode foils (cathode and anode) used in lithium-ion batteries (LIB) critical to the electric vehicle industry. These solutions incorporate several of Marposs’ noncontact measurement and inspection technologies to provide fast, high-resolution film thickness and width gauging across the electrode production process, helping to avoid scrap and rework to improve quality and save money.

Confocal measurement during electrode coating and calendaring

For electrode formation, copper or aluminum foil and slurry are mixed with a solvent and coated roll-to-roll on the metal substrate as a liquid film. During the drying process, it’s critical to control the homogeneity and uniformity of the coated electrode. Once dried, the films go through a calendaring process where the electrode coil is passed through a roll press to decrease the film thickness and the porosity to increase energy density and flatten its surface. If compressed too much, the electrode porosity could be reduced to a level where the electrolyte can’t penetrate in its structure, so deviations in the electrode thickness must be carefully controlled.

Marposs’ STIL Chromatic Confocal technology enables high-frequency sampling by providing geometrical measurement and inspection during these critical process steps to measure and identify any film width or thickness aberrations. Confocal uses white light and reflected optical beams from surfaces of the object being measured, which are sent to a spectrometer for electronic processing to determine the thickness values of the web.

Laser micrometer inspection during electrode slitting

After film production, the electrode mother roll is split into smaller daughter rolls using ceramic blades. Geometric measurement is required to identify the wrong position of the blade or the electrode being slit. Marposs’ AEROEL laser scanners can be used to provide quick, accurate, and efficient measurement of the daughter roll width during this R2R process. These laser gauges feature patented technologies that make them accurate and reliable because they are impervious to variations in temperature, vibration, product movement, dust, and other environmental conditions that would normally influence measurement results.

In-line machine vision inspection during electrode notching

To produce the pouch cell requires separating the anode, cathode, and separator sheets from the roll material. This process, also known as notching, is usually performed with a shear cut (punching tool) or laser cut in a continuous process. Marposs’ patent-pending in-line machine vision system identifies the existence of burrs, folds, and delamination of the electrode profile during this process. This system uses a high-resolution linear camera that frames the edge of the electrode to acquire a series of digital images, which are analyzed to check for the possible presence of metal burrs. The system also includes a matrix camera, which detects a change in distance between the edge of the electrode and the linear camera.

Complete information about measurement, inspection, and test solutions for R2R can be found at here or by contacting Marposs Corp. by phone at (248) 370–0404 or by emailing marposs@us.marposs.com.

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