Abstract: The disclosed subject matter relates to a method and system for detecting failures in a cell measuring circuit for a vehicle battery including a plurality of battery cells. First the method includes determining a cell voltage of each of the plurality of cells by the respective cell measuring circuit. Next, the method includes performing cell balancing to balance a cell voltage for the plurality of cells and the cell balancing times are compared to determine if there are deviating cell balancing times, and if there is an identifiable pattern in the cell balancing times which can provide an indication of a failure in any of the cell measuring circuits.

Abstract: A method for estimating a capacity of an electrical energy storage device with higher accuracy than what is provided in the prior art. The uncertainties in measured electrical current or voltage used in the estimation of the capacity of the electrical energy storage device are at least partly compensated for by using a bias compensated capacity estimator instead of the often-used prior art capacity estimator. The accuracy of the voltage and/or electric current sensor becomes of less importance which leads to that less complicated and less costly sensors may be used and to improve accuracy of the estimated energy storage capacity. The above advantages are obtained by providing a bias compensated capacity estimator that includes at least one bias term which is related to a deviation of an expected value of an original capacity estimator from a true capacity value.

Abstract: The disclosed subject matter relates to a method and system for detecting failures in a cell measuring circuit for a vehicle battery including a plurality of battery cells. First the method includes determining a cell voltage of each of the plurality of cells by the respective cell measuring circuit. Next, the method includes performing cell balancing to balance a cell voltage for the plurality of cells and the cell balancing times are compared to determine if there are deviating cell balancing times, and if there is an identifiable pattern in the cell balancing times which can provide an indication of a failure in any of the cell measuring circuits.

Abstract: A method for estimating a capacity of an electrical energy storage device with higher accuracy than what is provided in the prior art. The uncertainties in measured electrical current or voltage used in the estimation of the capacity of the electrical energy storage device are at least partly compensated for by using a bias compensated capacity estimator instead of the often-used prior art capacity estimator. The accuracy of the voltage and/or electric current sensor becomes of less importance which leads to that less complicated and less costly sensors may be used and to improve accuracy of the estimated energy storage capacity. The above advantages are obtained by providing a bias compensated capacity estimator that includes at least one bias term which is related to a deviation of an expected value of an original capacity estimator from a true capacity value.