Abstract: 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.

Abstract: 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.

Abstract: A method for estimating a state of a battery pack using a controller having battery state estimator (BSE) logic includes receiving or delivering a constant baseline current via the battery pack. Current oscillations having time-variant frequency content are selectively injected into the baseline current via the controller in response to a predetermined condition. The baseline current and the current oscillations combine to form a final current. The method includes estimating a battery parameter via the BSE logic concurrently with the current oscillations to generate an estimated battery parameter, and estimating the present state of the battery pack via the controller using the estimated battery parameter. An electrical system includes a rotary electric machine that is electrically connected to and driven by the battery pack, and a controller configured to execute the method.

Abstract: A battery system is electrically connected to a power bus that is arranged to supply electric power to an on-vehicle actuator such as an electric traction machine. Controlling electric power flow in the battery pack includes determining states of charge for the plurality of battery packs, identifying one of the battery packs as a weakest battery pack based upon the states of charge, and determining an internal circulating current being transferred via the wiring harness that is associated with charging of the weakest battery pack. Electric power transfer through the wiring harness and the power bus is controlled such that the internal circulating current is less than an internal circulating current limit. In one embodiment, the internal circulating current limit is determined in relation to battery temperature.

Abstract: A system and associated method are described for balancing an electrical parameter associated with stored electric power in a multi-cell battery. A cell charge balancing system determines a first plurality of the electrical parameters associated with respective ones of the plurality of cells, a plurality of first charge parameters associated with the cells, and a first quality index. A second plurality of the electrical parameters are determined, and second charge parameters are determined to determine a second quality index. The first and second quality indices are compared, and a cell charge balancing routine controls the balancing system based upon the first quality index when the first quality index is greater than the second quality index. The cell charge balancing routine controls the cell charge balancing system based upon the second quality index when the first quality index is less than the second quality index.

Abstract: A method for estimating a state of a battery pack using a controller having battery state estimator (BSE) logic includes receiving or delivering a constant baseline current via the battery pack. Current oscillations having time-variant frequency content are selectively injected into the baseline current via the controller in response to a predetermined condition. The baseline current and the current oscillations combine to form a final current. The method includes estimating a battery parameter via the BSE logic concurrently with the current oscillations to generate an estimated battery parameter, and estimating the present state of the battery pack via the controller using the estimated battery parameter. An electrical system includes a rotary electric machine that is electrically connected to and driven by the battery pack, and a controller configured to execute the method.

Abstract: A battery system is electrically connected to a power bus that is arranged to supply electric power to an on-vehicle actuator such as an electric traction machine. Controlling electric power flow in the battery pack includes determining states of charge for the plurality of battery packs, identifying one of the battery packs as a weakest battery pack based upon the states of charge, and determining an internal circulating current being transferred via the wiring harness that is associated with charging of the weakest battery pack. Electric power transfer through the wiring harness and the power bus is controlled such that the internal circulating current is less than an internal circulating current limit. In one embodiment, the internal circulating current limit is determined in relation to battery temperature.

Abstract: 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.

Abstract: A method for estimating remaining energy in a battery pack having series-connected cells/cell groups includes measuring battery parameters, including a battery voltage, current, and temperature. The controller estimates a static state of charge difference (?SOC) value and a current-dependent ?SOC value in real-time using the parameters, including calculating the static ?SOC value as a difference between an average SOC of the battery pack and an SOC of a weakest/lowest energy cell group. The current-dependent ?SOC value is a percentage SOC per unit of the current. The static ?SOC value and current-dependent ?SOC values are filtered via a multi-parameter state estimator block. Using the filtered state values, the controller executes a control action responsive to the estimated remaining energy, including displaying the remaining energy and/or a quantity derived from the remaining energy via a display device. A powertrain system includes the controller, electric machine, and battery pack.

Abstract: A system and associated method are described for balancing an electrical parameter associated with stored electric power in a multi-cell battery. A cell charge balancing system determines a first plurality of the electrical parameters associated with respective ones of the plurality of cells, a plurality of first charge parameters associated with the cells, and a first quality index. A second plurality of the electrical parameters are determined, and second charge parameters are determined to determine a second quality index. The first and second quality indices are compared, and a cell charge balancing routine controls the balancing system based upon the first quality index when the first quality index is greater than the second quality index. The cell charge balancing routine controls the cell charge balancing system based upon the second quality index when the first quality index is less than the second quality index.

Abstract: A method for estimating remaining energy in a battery pack having series-connected cells/cell groups includes measuring battery parameters, including a battery voltage, current, and temperature. The controller estimates a static state of charge difference ( ?SOC) value and a current-dependent ?SOC value in real-time using the parameters, including calculating the static ?SOC value as a difference between an average SOC of the battery pack and an SOC of a weakest/lowest energy cell group. The current-dependent ?SOC value is a percentage SOC per unit of the current. The static ?SOC value and current-dependent ?SOC values are filtered via a multi-parameter state estimator block. Using the filtered state values, the controller executes a control action responsive to the estimated remaining energy, including displaying the remaining energy and/or a quantity derived from the remaining energy via a display device. A powertrain system includes the controller, electric machine, and battery pack.