Gm Global Technolgoy Operations, Inc.

Jeffrey A Bednar

Justin Bunnell

Brian James Koch

Jing Gao

Garrett M Seeman

Jeffrey S Piasecki

Charles Weldon Wampler, Ii

Alfred Zhang

Justin R McDade

Xavier Camacho Tardi

Xiumei Guo

A battery system includes a multi-cell rechargeable energy storage system (RESS) and an electronic controller configured to process RESS cell data. The controller is programmed with a battery cell open circuit voltage (OCV) versus state of charge (SOC) data table used to calculate a peak OCV movement for a representative battery cell at predetermined capacity and maximum discharge/charge rate. The controller is configured to acquire voltage data for one of the cells during active RESS cycling. The controller is also configured to pass the acquired voltage data through a first-order lag filter algorithm to generate an overpredicted OCV for the subject cell. The controller is additionally configured to determine an overpredicted SOC value for the subject cell in the data table using an OCV value from the overpredicted OCV. Furthermore, the controller is configured to regulate the RESS using the determined overpredicted SOC value for the subject cell.

Determination and utilization of over-predictive battery state of charge

A method for battery capacity estimation is provided. The method includes monitoring a sensor, collecting a plurality of data points including a voltage-based state of charge value and an integrated current value, defining within the data points a first data set collected during a first time period and a second data set collected during a second time period, determining an integrated current error related to the second data set, comparing the integrated current error related to the second data set to a threshold integrated current error. When the error related to the second data set exceeds the threshold, the method further includes resetting the second data set based upon an integrated current value from the first time period. The method further includes combining the data sets to create a combined data set and determining a voltage slope capacity estimate as a change in integrated current versus voltage-based state of charge.

Method and system for battery capacity estimation using voltage slope capacity and dynamic anchors

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South Lyon, MI, United States of America

Jeffrey A Bednar