Nondestructive Testing: Electromagnetic System

Electromagnetic System for Quality Assurance of Battery Semi-Products

Non-contact eddy-current based measurements using proprietary sensor arrays can determine flaws in multi-layered battery, solar cell, and supercapacitor components during manufacture.

Quality assurance testing for interior defects in electrochemical devices such as batteries, solar sells and super-capacitors is most often done off-line using x-rays. X-ray based testing equipment is generally expensive and difficult to adapt for manufacturing line application. Use of x-rays also requires that safety precautions be taken to protect workers.


Enerize has developed a non-contact, nondestructive method for determining integrity of internal layered structures such as electrodes in such batteries and supercpacitors. This NDT equipment can be used for determining conductivity, as well as for detecting defects such as cracks, voids, spalling and de-laminations in coated or multi-layered structures.

This sensor and controller system has the following features:

  • Unique transducer design that generates a homogeneous electromagnetic field.

  • Combined system includes eddy-current transducer and capacitance sensors.


  • Special device design includes an array of transducers and sensors along the test article.


  • Sensors operate at multiple frequencies which allow identification and categorization of defects in multi-layered structures.

Results of analyses carried out by eddy-current NDT on a set of dry electrode samples were compared to those from conventional by x-ray inspection. The defective electrode structure in the test set was readily identified by the eddy-current analysis. Closer inspection of the x-ray image confirmed a small separation in the layered structure.  


Unique features of the Enerize eddy current test system include:

  • Capability to test internal and surface defects on multi-layer structures. The layers can be either conductive or dielectric

  • Able to check flat layered structures as well as rolled construction components Addresses difficulty with testing interior layers of a rolled construction components

  • Non-contact method that can be set up for automated production lines

  • Able to differentiate among cracks or splits in layers; chips or crimps in layers; two layers fused through an insulator or separator