Battery State-Of-Charge Estimation For Hybrid And Electric Vehicles Using Extended Kalman Filter Techniques

A battery management system comprising:

• a plurality of sensors comprising:
• a voltage sensor electrically coupled to a battery pack,
• a current sensor electrically coupled to the battery pack, and
• a temperature sensor thermally coupled to the battery pack;
• and
• a battery management controller electrically coupled to the plurality of sensors and configured to sense one or more battery characteristics comprising a temperature of the battery pack, a voltage of the battery pack, and a current of the battery pack and the battery management controller comprising a processor and a computer-readable medium configured to run an algorithm to estimate the state of charge of the battery pack using an open circuit voltage and the temperature of the battery pack, the algorithm further comprising:
• at least one state stored in the computer-readable medium including a solid-state diffusion voltage effect,
• at least one equivalent circuit model parameter stored in the computer-readable medium, and
• an extended Kalman filter executed in the processor using the voltage of the battery pack, the current of the battery pack, the at least one state and circuit model parameters to calculate the open circuit voltage.

A method of estimating a state of charge of a battery pack in a vehicle, comprising:

• using a plurality of sensors electrically coupled to a battery pack, the plurality of sensors comprising:
• a voltage sensor electrically coupled to the battery pack,
• a current sensor electrically coupled to the battery pack, and
• a temperature sensor thermally coupled to the battery pack;
• executing an algorithm in a battery management controller electrically coupled to the plurality of sensors and configured to sense one or more battery characteristics comprising a temperature of the battery pack, a voltage of the battery pack, and a current of the battery pack, the algorithm further comprising:
• at least one state stored in a computer-readable medium including a solid-state diffusion voltage effect,
• at least one equivalent circuit model parameter stored in the computer-readable medium, and
• an adaptive estimation technique executed in a processor using the voltage of the battery pack, the current of the battery pack, the at least one state and circuit model parameters to calculate an open circuit voltage;
• and
• estimating a state of charge of the battery pack using the open circuit voltage and the temperature of the battery pack.