Khat, F. Zarrin, A. Pentland, P. F. Taday, and D. D. Arnone. "Terahertz Assessment of the Battery Electrodes Save Production Costs of Electric Vehicles." Journal of Non Destructive Testing and Evaluation (JNDE) 21, no. 2 (2024): 33-40.
Abstract
The electric vehicle market has experienced remarkable growth in recent years. A primary objective within this industry is to lower production costs. Notably, battery packs, which constitute up to 40% of the total production cost, allocate about 64% of this to the manufacturing of electrodes. It is vital to monitor key battery parameters such as thickness, loading, density, conductivity, and porosity to minimize waste during electrode production. Until recently, there was no technology capable of simultaneously tracking these parameters. However, terahertz technology has emerged as a powerful, non-destructive, and safe method for assessing battery electrodes.
Battery electrodes are coated on substrates made of materials like aluminium and copper. Since metals completely reflect terahertz waves, it's possible to measure the electrodes in reflection mode. This approach allows for the determination of the coating's thickness and its complex refractive index, which can be interpreted to deduce key electrode parameters.
In our study, we utilized TeraView's latest advancement, the TeraCota, a terahertz system designed for industrial applications, equipped with a self-referencing terahertz sensor. The sensor, mounted on a gantry, provided a terahertz image of the electrode loading and allowed for a direct comparison with an optical image, revealing defects on the cathode. We achieved an accuracy of 0.01 g/cm3 when comparing density measurements obtained through a terahertz sensor with those measured physically in the lab. Furthermore, the thickness measurements via the terahertz system agreed with those obtained using a micrometre to within less than 1 µm. Similarly, when comparing the conductivity measured by terahertz with DC conductivity measured via a four-point probe, the trends were consistent. Ongoing research into porosity has shown that the refractive index correlates with the porosity of specific electrode sets, indicating the potential for broader application. This comprehensive approach demonstrates the significant advantages of integrating terahertz technology into the battery electrode manufacturing process, potentially revolutionizing the industry by enhancing efficiency and reducing waste.
see https://jnde.isnt.in/index.php/JNDE/article/view/84
