Determining the internal resistance of a battery cell of a traction battery when using inductive cell balancing

摘要

The invention relates to a method and a device for determining the internal resistance of a battery cell (1a) of a battery (1), in particular traction battery, wherein in the battery (1) an inductive Zellbalancing to compensate for the charge states of the battery cells (1a) is performed, in which the charge taken or supplied to a battery cell (1a) is determined by detecting the current flowing during the charge extraction or supply. According to the invention, a first control module (3) for determining a first voltage applied to the battery cell (1a) and a first current flowing from or to the battery cell at a first time during the charge extraction or supply and for determining a at the battery cell (1a) applied second voltage and a second current flowing from or to the battery cell (1a) at a second time during the charge extraction or supply, and a computing unit (4) for calculating the internal resistance of the battery cell (1a) as the quotient of the difference of the second voltage and the first voltage provided with the difference of the second current and the first current.