Method for determining the health status of the vehicle battery of an electric vehicle or hybrid electric vehicle, comprising the following steps: - loading the vehicle battery and determining predetermined battery parameters, in particular battery pack voltage, battery pack current, cell voltage, battery module temperature and/or state of charge, preferably by the vehicle's battery management system, during the loading, - transmitting the determined battery parameters by means of a data transmission unit that can be plugged into a diagnosis connection of the vehicle, preferably in real time, to a data memory, in particular separate from the vehicle, and - calculating the health status of the vehicle battery on a server in data communication with the data memory using a vehicle-specific battery model based on the transmitted battery parameters. characterised in that a battery base model which is dependent on the type of vehicle battery and is in the form of an electrical equivalent circuit model is initially used as the vehicle-specific battery model, wherein the battery base model comprises a voltage source, an internal resistance (R 0) and a number of, in particular two, RC elements (RC 1, RC 2), - wherein the internal resistance (R 0) and RC elements (RC 1, RC 2) are determined as a function of cell temperature and state of charge, - wherein an open circuit voltage characteristic is established as a function of the state of charge, and - wherein the cell temperature is determined by means of a thermal model as a function of the measured battery pack current, EC parameters which are parameters of the electrical equivalent circuit model, the battery module temperature and an ambient temperature. - loading the vehicle battery and determining predetermined battery parameters, in particular battery pack voltage, battery pack current, cell voltage, battery module temperature and/or state of charge, preferably by the vehicle's battery management system, during the loading, - transmitting the determined battery parameters by means of a data transmission unit that can be plugged into a diagnosis connection of the vehicle, preferably in real time, to a data memory, in particular separate from the vehicle, and - calculating the health status of the vehicle battery on a server in data communication with the data memory using a vehicle-specific battery model based on the transmitted battery parameters. characterised in that a battery base model which is dependent on the type of vehicle battery and is in the form of an electrical equivalent circuit model is initially used as the vehicle-specific battery model, wherein the battery base model comprises a voltage source, an internal resistance (R 0) and a number of, in particular two, RC elements (RC 1, RC 2), - wherein the internal resistance (R 0) and RC elements (RC 1, RC 2) are determined as a function of cell temperature and state of charge, - wherein an open circuit voltage characteristic is established as a function of the state of charge, and - wherein the cell temperature is determined by means of a thermal model as a function of the measured battery pack current, EC parameters which are parameters of the electrical equivalent circuit model, the battery module temperature and an ambient temperature.