Abstract: Technologies and techniques for determining a maximum current limit of a battery system having at least two batteries. A separate current is measured at each of the at least two batteries, and a total current is measured of the battery system. For each of the measured separate currents, a current ratio is determined between the measured separate current in question and the measured total current. A maximum individual current limit of the battery system is determined for each of the at least two batteries on the basis of the determined current ratio in question and a nominal maximum current limit of the battery in question. The smallest determined maximum individual current limit is selected as a maximum current limit of the battery system and the determined maximum current limit is provided as a maximum current limit signal. Alternatively, or additionally, the measurements can also be carried out using resistances.

Abstract: Technologies and techniques for estimating an internal resistance of a battery cell. A voltage and a current are detected at the battery cell. A detected voltage differential is determined by differentiating the detected voltage using a filter, and a modelled voltage differential is determined from the detected current and an actual internal resistance estimation value is determined by differentiating using a filter. A correction factor is determined from the detected voltage differential and the modelled voltage differential, and a new actual internal resistance estimation value is estimated from the determined correction factor and the previous actual internal resistance estimation value, and the new actual internal resistance estimation value is provided as estimated internal resistance of the battery cell. A device configured for estimating an internal resistance of a battery cell is further disclosed.

Abstract: Technologies and techniques for determining an energy quantity in a battery or battery cell, wherein an initial charge state and a final charge state is received. A load profile between the initial charge state and the final charge state is received, and intermediate charge states between the initial charge state and the final charge state and associated weighting factors are determined. Parameters of an equivalent circuit model of the battery or the battery cell are estimated for each of the determined intermediate charge states, and, proceeding from the load profile, the weighting factors and the parameters, an energy quantity of the battery or battery cell between the initial charge state and the final charge state is determined and is provided as an energy quantity signal. An associated control device for determining an energy quantity in a battery or battery cell is also disclosed.