Ferromagnetic Analysis for Lithium-Ion Battery Cathode QA/QC

Manufacturing lithium-ion batteries (LiBs) involves a series of complex production steps, and defects introduced at any step can lead to batteries which must be discarded. The primary QA/QC testing occurs at the end of production, on assembled and charged batteries; this is costly, time consuming, wasteful and costly. Relying on end of line electrical QA/QC testing also makes determining failure modes of defective batteries very difficult. Costs are greatly increased if flaws introduced early in the process are not discovered until the end. Better QA/QC testing, that assesses material structure and chemistry at intermediary steps, is needed to make production more efficient and lower costs, which supports wider spread adoption of LiB powered technologies. LiBs are composed of many magnetically active materials. TDA proposes use of the correct range of small, inexpensive magnetometers to make in-line measurements of the magnetic field of cathode materials and the battery cells, both during the assembly process and after they are complete. Magnetic field changes will provide information of the structure of the active cathode material within the battery, better identifying production defects. The magnetic signature of raw materials will be characterized and compared to magnetometry measurements of representative cathode films and assembled battery cells. Properly manufactured samples and samples with induced defects will be assessed. Sensitivity and resolution will be defined, with the goal of creating a sensing array of magnetometers that could be installed in a manufacturing line, to successfully identify materials-based, production defects at the step where they occur. Improved QA/QC will make the LIB manufacturing process more efficient and help bring new LIB technologies to production scale more smoothly. This will reduce the cost of electric vehicles, personal electronics, and large scale energy storage equipment.