Apparatus for predicting power parameter of secondary battery

A battery system for predicting a target power parameter of battery cells, the battery system comprising:

• a secondary battery configured to receive and supply power;
• a plurality of sensors each measuring variables of the battery system;
• a memory;
• and
• a processor operatively coupled to the secondary battery, the plurality of sensors, and the memory, the processor being configured to:
• calculate a present polarization voltage across the secondary battery at a specified prediction time based on an equivalent circuit model of the secondary battery, the equivalent circuit model including:
• a DC resistance model representing a DC resistance of the secondary battery;
• a reaction impedance model representing a reaction resistance of the secondary battery and having a nonlinear relationship between a first potential difference across the reaction resistance and a current flowing through the secondary battery, the nonlinearly relationship depending on a temperature of the secondary battery;
• and
• a diffusion impedance model representing a diffusion impedance of the secondary battery and including at least one RC parallel circuit, the at least one RC parallel circuit including a diffusion resistance and a diffusion capacitance connected in parallel to each other, the DC resistance model, the reaction impedance model, and the diffusion impedance model being connected in series to each other;
• calculate the present polarization voltage across the secondary battery in accordance with a predetermined function defined among the present polarization voltage, the diffusion resistance, and the diffusion capacitance;
• calculate, in accordance with a first continuous time-domain function, a predicted remaining voltage across the secondary battery at a time after a predetermined time since the specified prediction time for the target power parameter, the first continuous time-domain function being defined by the diffusion resistance, the diffusion capacitance, the present polarization voltage, and the future remaining voltage;
• calculate, in accordance with a second continuous time-domain function, a predicted polarization voltage across the secondary battery at the timing after the predetermined time since the specified prediction time, the second continuous time-domain function being defined by the future polarization voltage, the diffusion resistance, and the diffusion capacitance;
• determine a value of the target power parameter at the timing after the predetermined time since the specified prediction time in accordance with:
• the predicted remaining voltage, the predicted polarization voltage, the first potential difference across the reaction resistance, a second potential difference across the DC resistance model, and a value of the current flowing through the secondary battery measured by one of the plurality of sensors;
• and
• control performance of the secondary battery in accordance with the determined value of the target power parameter.