METHOD OF CHARACTERISING A BATTERY

A method of characterising a condition of an electrochemical cell 100 comprising a plurality of electrodes, the method comprising: positioning one or more magnetometers 200 adjacent to an electrode surface of the electrochemical cell to measure magnetic field of the electrochemical cell at a first location 202; measuring the magnetic field generated by the electrochemical cell for a predetermined length of time, the measuring providing a first temporal profile of the magnetic field in an x-direction and a second temporal profile of the magnetic field in a y-direction, at the first location; confirming occurrence of a transient current inhomogeneity within the electrochemical cell based on identifying a step-change in an x-component of the magnetic field from the first temporal profile and a coincident step-change in a y-component of the magnetic field from the second temporal profile; and determining a characteristic of the electrochemical cell based on the occurrence of transient current inhomogeneities.