Karma Automotive LLC

Ali Jokar

Jing Hong

Suvrat Ramasubramanian

A method of estimating a maximum power limit of a battery cell at a specified prediction time using an improved RC equivalent circuit battery model and based on the battery cell's state of charge (SOC), temperature, and state of health (SOH). The method includes determining the battery cell's peak and continuous current limits, predicting a peak voltage after the specified prediction time based on the peak current limit, determining buffer values for the predicted peak voltage and the temperature of various battery components, setting a maximum current limit based on the buffer values, predicting a maximum voltage after the specified prediction time based on the maximum current limit, and determining a maximum power limit based on the predicted maximum voltage and the maximum current limit.

Battery power limits estimation based on RC model

A method of estimating a battery current limit for operation of a battery cell over the course of a specified prediction time. The method includes generating a plurality of current limit estimations by means of a plurality of current limit estimation sub-methods, wherein at least one current limit estimation sub-method generates its current limit estimation based on an RC equivalent circuit model of the battery cell, and determining the charge current limit by finding the lowest magnitude current limit estimation in the plurality of current limit estimations. At least one parameter of the RC equivalent circuit model is set based on the specified prediction time and at least one variable from the set of: a state of charge (SOC) of the battery cell, a temperature of the battery cell, a state of health (SOH) of the battery cell, a capacity of the battery cell, and a current of the battery cell.

Battery current limits estimation based on RC model

A method of determining the state of charge (SOC) of a battery. The method includes receiving battery parameters for a battery, and based on the received battery parameters for the battery, determining an estimated voltage of the battery and determining an estimated SOC of the battery. The method also includes receiving a measured voltage of the battery, determining a voltage error value based on the measured voltage of the battery and the estimated voltage of the battery, correcting, using the voltage error, the estimated SOC to determine a corrected SOC for the battery, and operating the battery based on the corrected SOC.

Method of determining the state of charge of a battery used in an electric vehicle

A method of determining the state of charge (SOC) of a battery. The method may employ a transformation technique that linearizes a nonlinear model by converging close to a measured value and thereby estimating the state of charge accurately without affecting the computation time and load on the system. The transformation technique employs an adaptive unscented Kalman filter (UKF).

A method of estimating the residual energy of a battery. The method comprises determining the battery's state of charge (SOC) and dischargeable capacity to determine the battery's state of energy (SOE), determining the battery's reference dischargeable energy (E) and total dischargeable energy (E), and comparing the state of energy to the total dischargeable energy to find the residual energy of the battery. The various functions of the method use battery current, cell temperature, and state of health (SOH) as variables for consideration.

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Irvine, CA, United States of America

Ali Jokar