Camera-based quality control to detect battery flaws

The electrodes - anodes and cathodes - are copper on one side and coated with a black compound to store lithium on the other. Lithium ions travel from the anode to the cathode while the battery is being charged and in the reverse direction when discharging energy.

The material expands as lithium ions travel into it, and this expansion and contraction causes mechanical stresses that can eventually damage a battery and reduce its lifetime, said Douglas Adams, Kenninger Professor of Mechanical Engineering and director of the Purdue Center for Systems Integrity.

The coating is a complex mixture of carbon, particulates that store lithium, chemical binders and carbon black. The quality of the electrodes depends on this coating (or battery paint) being applied with uniform composition and thickness.

‘A key challenge is to be able to rapidly and accurately sense the quality of the battery paint,’ said James Caruthers, Reilly Professor of Chemical Engineering and co-inventor of the new sensing technology.