Gm Global Technolgoy Operations, Inc.

Michael Wahlstrom

David R Clark

Ciro A Spigno

Zachary D Bylsma

Christopher W Mousseau

System and methods for estimating a temperature of a battery are presented. In some embodiments, a method of estimating a temperature of a battery system may utilize measured battery system temperature data and measured ambient temperature data. Based on the measured temperature data, an average estimated temperature of the battery system may be determined using, at least in part, an extended Kalman filter and an energy balance process model associated with the battery system.

Systems and methods for battery system temperature estimation

A method for estimating charge capacity of a lithium iron-phosphate battery pack using data from a plug-in charge event. A laboratory-measured battery pack resistance, which is known to remain constant over a battery pack's life, can be used to determine open circuit voltage from terminal voltage during charging. Actual open circuit voltage after charging can be measured later, after the battery pack has rested for a sufficient amount of time. The two values of open circuit voltage, if taken at points on the battery pack's SOC-OCV curve which have great enough slope, provide two values of battery pack state of charge. By integrating charging current over the time interval between the two open circuit voltage readings, and using the two state of charge values, the battery pack capacity can be determined from the plug-in charge data.

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Walled Lake, MI, United States of America

Michael Wahlstrom