| CPC G01R 31/392 (2019.01) [B60L 58/12 (2019.02); B60L 58/16 (2019.02); G01R 31/367 (2019.01); G01R 31/388 (2019.01); B60L 2240/545 (2013.01); B60L 2240/547 (2013.01); B60L 2240/549 (2013.01); B60L 2240/70 (2013.01)] | 13 Claims |

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1. A method for determining a vehicle battery's state of health in an electric or hybrid vehicle, comprising the following steps:
connecting the vehicle battery to a load and determining values for predefined battery parameters, in particular the battery pack voltage, battery pack current, cell voltage, battery module temperature, and/or state of charge, preferably with the battery management system in the vehicle while the battery is in use,
sending these parameter values to a data storage unit, in particular outside the vehicle, preferably in realtime, in particular by means of a data transfer unit that can be plugged into a diagnosis socket in the vehicle, and
calculating the vehicle battery's state of health on a server connected to the data storage unit for data transfer based on the obtained battery parameter values, using a vehicle-specific battery model,
characterized in that a basic battery model in the form of an equivalent circuit model relating to the type of vehicle battery is initially used for the basis of the vehicle-specific battery model, wherein the basic battery model comprises a power source, an internal resistance, and a number of RC circuits, in particular two,
wherein the internal resistance and the RC circuits reflect the cell temperature and the state of charge,
wherein the open-circuit voltage is a function of the state of charge, and
wherein the cell temperature is determined using a thermal model based on the measured battery pack current, EC parameters, in particular the parameters for the equivalent circuit model, the battery module temperature, and the ambient temperature.
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