Gm Global Technolgoy Operations, Inc.

Joseph Bisbing

Brian James Koch

Damon R Frisch

Daniel P Grenn

James C Gibbs

Kurt M Johnson

In accordance with exemplary embodiments, battery capacity of an electric vehicle can be automatically determined. In an exemplary method, an instruction is received to determine a battery capacity value and one or more vehicle accessories are activated to discharge the battery to a first charge level. When the first charge level is reached, a generator in the vehicle is started and used to charge the battery to a second charge level, after which the battery capacity value can be determined and stored. In accordance with the exemplary embodiments, the vehicle comprises a controller adapted to cause a battery to be discharged and charged to determine a capacity value of the battery. A plurality of accessories are configured to activate and deactivate responsive to the controller to discharge the battery, while a generator is responsive to the controller to charge the battery so that the controller can determine the battery capacity value.

System and method for determining battery capacity in an electric vehicle

A method and system for use with a vehicle battery pack having a number of individual battery cells, where the method estimates, extrapolates or otherwise determines individual cell resistances. According to an exemplary embodiment, the method and system use a voltage and temperature reading for each of the individual battery cells, as well as a voltage and current reading for the overall battery pack to determine one or more cell resistance values, such as a minimum and maximum cell resistance for the battery pack. This approach relies upon temperature deviations in the battery pack to make assumptions or estimates regarding individual battery cell resistances. By having individual cell resistance values&#x2014;instead of using an overall pack resistance value and building in a buffer to account for cell variations&#x2014;better and more accurate cell-level data can be obtained that, in turn, can improve charging, discharging, cell balancing and/or other battery-related processes.

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White Lake, MI, United States of America

Joseph Bisbing