Method and system for determining a state of charge of a battery

A method for determining a state of charge of a battery comprising:

• calculating first and second properties of the battery;
• calculating a first component of the state of charge based on the first property of the battery;
• calculating a second component of the state of charge based on the second property of the battery;
• weighting the first component of the state of charge proportionally to a rate of change of the first property relative to a change of the state of charge;
• weighting the second component of the state of charge proportionally to a rate of change of the second property relative to a change of the state of charge;
• and
• determining the state of charge based on the first and second weighted components.

An automotive drive system comprising:

• an electric motor;
• a battery coupled to the electric motor;
• a sensor assembly coupled to the battery and configured to detect at least one characteristic of the battery and generate signals representative thereof, and
• a processor in operable communication with the sensor assembly and configured to:
• receive the signals from the sensor assembly;
• calculate first and second components of a state of charge of the battery based on the signals;
• weight the first and second components of the state of charge proportionally to respective rates of change of the first and second properties relative to a change in the state of charge of the battery;
• and
• determine the state of charge of the battery based on the first and second weighted components.