In-Field Magnetometry for Determination of Lithium Battery SOC

By 2030 the entire lithium-ion battery chain, from mining through recycling, is expected to reach a value of $400 billion and a market size of 4.7 TWh. LiB are used in personal electronic devices, e-bikes, tools, green-power storage and electric vehicles. Individual cells are commonly collected into packs or modules to provide the power required for automotive operation. The operational capability of the entire module can be heavily influenced by defects or poor performance of individual cells, and is assessed through knowledge of the state-of-charge (SOC) at the cell and module levels. The SOC is a thermodynamic assessment of battery potential energy, related to the batteries state-of-health, and also determines the severity of thermal run-away events. Current methods of battery health and SOC are proprietary battery management systems (BMS), requires destruction of the battery, or are difficult to implement. To minimize damage caused by battery fires, or to prevent battery fires, a non-destructive sensor which can monitor LiB SOC during use and shipment is proposed. TDA Research has proposed such a sensor, based on readout of the magnetic field amplitude of battery cells using a field portable magnetometer.