Abstract: An electrified vehicle has a battery pack comprising series-connected battery units providing a main voltage. To supply a lower voltage bus equally from all battery units, a plurality of DC/DC converters are powered by respective units and have their outputs in parallel. A central module has an outer loop controller generating a target current to regulate the bus voltage to a predetermined voltage and has an allocator distributing the target current into a plurality of allocated current commands according to respective states of charge of the battery units. A plurality of local controllers each adjusts a current of a respective DC/DC converter. Each local controller receives a respective allocated current command as a respective feedforward control variable. Each local controller uses an error between the bus voltage and the predetermined voltage to be integrated as a respective feedback control variable only when the error is above a threshold.

Abstract: An electrified vehicle high voltage battery pack has series-connected battery units or cells combining to provide the high voltage. To power a low voltage bus (e.g., for low voltage accessories or charging a low voltage battery) in a balanced manner, a plurality of DC/DC converters each has an input coupled to a respective battery unit and the converters have respective outputs coupled in parallel to the low voltage bus. A first loop controller receives an actual bus voltage. The first controller generates a target current in response to the bus voltage adapted to regulate the actual bus voltage to a target voltage less than the high voltage. A second controller distributes the target current into a plurality of allocated current commands for respective converters according to respective states of charge of the battery units connected to the converters.

Abstract: A traction battery of a vehicle includes a temperature compensated passive wireless surface acoustic wave sensor within the traction battery and a controller. The temperature compensated passive wireless surface acoustic wave sensor is configured to receive a broadcast signal and transmit a reflected signal. The controller is programmed to transmit the broadcast signal and receive the reflected signal, and based on a difference in phase and amplitude between the broadcast and reflected signals indicative of an increase in pressure within the traction battery, stop charging the traction battery.

Abstract: A vehicle having a battery pack with cells arranged in at least groups of two cells in series is disclosed. A controller balances the cells based on a change in voltage across the cells being different than an expected change in voltage. The expected value is based on a current and a time associated with charging or discharging the cells. A controller is disclosed that commands charging and discharging of the battery cells based on a difference between a voltage across the group and the expected value for the group. A method for charging and discharging a battery pack is disclosed. The voltage across a group of cells is measured and compared to an expected value. An imbalance in a cell attribute is estimated according to a difference between the measured voltage and the expected voltage. The voltage across each battery cell is not required.

Abstract: A battery controller with monitoring logic for a model-based battery control of a battery performs battery current characterizing, parameter and state variable abnormality detection, and bound checking of error signals between measured and predicted output variables to generate an output. Switching between closed-loop operation (i.e., the model-based battery control) and open-loop operation (i.e., a traditional battery control) is done based on the output of the monitoring logic such that closed-loop stability and performance are reasonably guaranteed.

Abstract: A vehicle includes a traction battery and a controller coupled to the traction battery and having a memory, the controller being programmed to control the traction battery based on a difference between a total resistance indicated by voltage and current at a first operating condition and a battery cell resistance associated with the first operating condition previously stored in the memory, the difference being indicative of a wiring resistance associated with electrical connectors such as wires, cables, bus bars, and the like of the battery. The battery or the vehicle may be controlled in response to the adaptively determined wiring resistance by adjusting subsequent voltage or current determinations used to determine state of charge and battery capacity and/or to control charging or discharging of the battery and selection of various vehicle operating modes.

Abstract: A hybrid or electric vehicle includes a traction battery to store and provide energy for the vehicle. The traction battery includes a number of battery cells. For effective operation of the traction battery, operating parameters, such as state of charge and battery power limits, may need to be known. The operating parameters may be a function of battery cell voltage and impedance parameters. A parameter estimation scheme may use measured cell voltages and a measured traction battery current as inputs. A current measurement bias may be modeled that incorporates measurement bias caused by asynchronous current and voltage measurements. The current measurement bias may be estimated for each cell and the value may differ between cells.

Abstract: A hybrid or electric vehicle includes a traction battery to store and provide energy for the vehicle. The traction battery includes a number of battery cells. For effective operation of the traction battery, operating parameters, such as state of charge and battery power limits, may need to be known. The operating parameters may be a function of battery cell voltage and impedance parameters. A parameter estimation scheme may use measured cell voltages and a measured traction battery current as inputs. A current measurement bias may be modeled that incorporates measurement bias caused by asynchronous current and voltage measurements. The current measurement bias may be estimated for each cell and the value may differ between cells.

Abstract: An apparatus includes a battery state module that determines a battery state of each of a plurality of battery cells forming a battery unit. A battery state includes a health of the battery cell. A battery state of a battery cell differs from a battery state of other battery cells of the battery unit. Each battery cell is connected to a shared bus through a bypass converter that provides power from the battery cell to the shared bus. A charge/discharge modification module determines, based on battery state, an amount to vary a charging characteristic for each battery cell compared to a reference charging characteristic. Each charging characteristic varies as a function of a reference state. A charge/discharge module adjusts charging/discharging of a battery cell of the battery unit based on the charging characteristic of the battery cell.

Abstract: An apparatus for model predictive control (“MPC”) is disclosed. A method and system also perform the functions of the apparatus. The apparatus includes a measurement module that receives battery status information from one or more sensors receiving information from a battery cell, and a Kalman filter module that uses a Kalman filter and the battery status information to provide a state estimate vector. The apparatus includes a battery model module that inputs the state estimate vector and battery status information into a battery model and calculates a battery model output, the battery model representing the battery cell, and an MPC optimization module that inputs one or more battery model outputs and an error signal in a model predictive control algorithm to calculate an optimal response. The optimal response includes a modification of the error signal.

Abstract: A vehicle is disclosed comprising a battery and a controller. Projected battery impedance parameters are calculated based on predetermined parameter values and historical parameter values generated by a battery parameter estimation model. The values may be weighted according to time data associated with the historical impedance parameter values and a temperature of the battery. Recent historical impedance parameter values may affect the projected battery impedance parameter values more than older historical impedance parameter values. The model is initialized with projected parameter values at vehicle initialization. Battery power capability is calculated using the projected parameter values for a period of time following vehicle initialization. After the period of time following vehicle initialization, battery power capability is calculated using impedance parameters generated by the model. The period of time following vehicle initialization may end when the model output has converged to a stable solution.

Abstract: An electric vehicle includes a controller configured to estimate battery capacity in accordance with a first state of charge estimation, a charge integration, and a second state of charge estimation. The first and second state of charge estimations are in accordance with time and temperature constraints and are such that the estimated battery capacity has limited uncertainty. The controller is further configured to generate an output based on the estimated battery capacity.

Abstract: A diagnostic method for contact resistance failure includes estimating electrical contact surface resistance of at least one contactor, determining a faulted status of the at least one contactor and indicating the faulted status of the at least one contactor if the at least one contactor is in the faulted status.

Abstract: For battery control, an apparatus includes a shared bus and a plurality of isolated direct current (DC) to DC bypass converters. Each bypass converter is associated with one battery unit. Inputs of each bypass converter are in parallel electrical communication with the associated battery unit. Outputs of each bypass converter are in parallel electrical communication with the shared bus. Each bypass converter estimates a battery state for each battery unit and controls the battery state to a reference state.

Abstract: A hybrid or electric vehicle includes a traction battery to store and provide energy for the vehicle. The traction battery includes a number of battery cells. For effective operation of the traction battery, operating parameters, such as state of charge and battery power limits, may need to be known. The operating parameters may be a function of battery cell voltage and impedance parameters. A parameter estimation scheme may use measured cell voltages and a measured traction battery current as inputs. A current measurement bias may be modeled that incorporates measurement bias caused by asynchronous current and voltage measurements. The current measurement bias may be estimated for each cell and the value may differ between cells.

Abstract: A vehicle is disclosed comprising a battery and a controller. Projected battery impedance parameters are calculated based on predetermined parameter values and historical parameter values generated by a battery parameter estimation model. The values may be weighted according to time data associated with the historical impedance parameter values and a temperature of the battery. Recent historical impedance parameter values may affect the projected battery impedance parameter values more than older historical impedance parameter values. The model is initialized with projected parameter values at vehicle initialization. Battery power capability is calculated using the projected parameter values for a period of time following vehicle initialization. After the period of time following vehicle initialization, battery power capability is calculated using impedance parameters generated by the model. The period of time following vehicle initialization may end when the model output has converged to a stable solution.

Abstract: A vehicle having a battery pack with cells grouped into subsets and at least one controller programmed to charge and discharge the battery pack is disclosed. A control output is generated based on a pack state of charge derived from each cell's initial state of charge at vehicle activation and an electric charge accumulated or spent by less than all of the cells of each of the subsets since vehicle activation. A method of estimating battery pack state of charge is disclosed in which a pack state of charge is calculated by identifying subsets of cells having similar properties and calculating an electric charge accumulated or spent for fewer than all of the cells of each subset. A cell state of charge is calculated for all cells based on an average electric charge accumulated or spent. The pack state of charge is based on all the cell states of charge.

Abstract: A vehicle having a battery pack with cells arranged in at least groups of two cells in series is disclosed. A controller balances the cells based on a change in voltage across the cells being different than an expected change in voltage. The expected value is based on a current and a time associated with charging or discharging the cells. A controller is disclosed that commands charging and discharging of the battery cells based on a difference between a voltage across the group and the expected value for the group. A method for charging and discharging a battery pack is disclosed. The voltage across a group of cells is measured and compared to an expected value. An imbalance in a cell attribute is estimated according to a difference between the measured voltage and the expected voltage. The voltage across each battery cell is not required.

Abstract: A method of controlling an electric vehicle including an internal combustion engine, a battery having a state of charge (SOC) and an open circuit voltage (OCV), includes establishing a system for estimating battery SOC. The system includes (i) a parameter estimation subsystem including a recursive parameter estimator for identifying battery parameters and (ii) an OCV estimation subsystem including a nonlinear adaptive observer for estimating battery OCV. Estimated battery OCV is related to estimated battery SOC by a mapping. An output is generated based on the estimated battery SOC.

Abstract: A battery system for powering a vehicle is provided. The system may include a first lithium-ion battery pack having a first total energy capacity and a first power to energy ratio (P/E ratio) and a second lithium-ion battery pack connected in parallel with the first lithium-ion battery pack and having a second total energy capacity that is higher than the first total energy capacity and a second P/E ratio that is lower than the first P/E ratio. A method of controlling the battery system is also provided, and may include controlling an operation of a vehicle according to a total power capability of the first and second battery strings, wherein the total power capability is the sum of a first battery string power capability and a second battery string power capability at a same voltage.