Abstract: A hybrid-electric vehicle includes a traction battery. A controller may operate the traction battery within certain state of charge and voltage limits. The controller may define a minimum operating voltage or state of charge below which no power may be requested from the traction battery. The minimum voltage and state of charge may be based on an electrical resistance of the traction battery. The voltage may also be based on a minimum power level required to crank the engine while meeting emissions standards. As the battery ages, the minimum voltage level may be adjusted such that the minimum power level is available at the minimum voltage level.

Abstract: An electric vehicle battery pack includes an array of battery cells each cell having an upper cell surface and a lower cell surface, the lower cell surface having a positive and a negative terminal; and a thermal assembly in thermally-conductive contact with the upper cell surfaces of the array. A battery pack cooling method is also disclosed.

Abstract: A battery management system for a vehicle includes a controller programmed to charge a battery at a predetermined charge rate. The controller discharges the battery for a predetermined time in response to a terminal voltage of the battery exceeding a predetermined voltage limit that results in a reduced charge rate. After discharging for the predetermined time, the controller resumes charging at the predetermined charge rate. A current magnitude during the discharge and the predetermined time may be based on factors including the predetermined charge rate, a battery temperature, and a charge current magnitude during charging.

Abstract: A battery management system for a vehicle includes a controller programmed to apply a current pulse to reverse a current flow through a battery to reduce or remove cell polarization. After the current pulse, an open-circuit voltage is measured as the terminal voltage of the battery. The settling time for the terminal voltage to approach the open-circuit voltage is reduced after the current pulse. The magnitude of the current pulse is based on a battery state of charge, a battery temperature, and a current magnitude prior to the current pulse.

Abstract: A method of detecting a leak in a battery pack according to an exemplary aspect of the present disclosure includes, among other things, calculating a predicted amount of thermal energy at a position, measuring an actual amount of thermal energy at the position, and comparing the predicted amount to the actual amount to identify if a battery pack is leaking.

Abstract: Systems and methods for operating a battery pack supplying power to propel a vehicle are disclosed. One example method comprises, adjusting a battery pack state of charge window in response to vehicle mass. Adjusting the battery pack state of charge window in response to vehicle mass may allow the battery pack to provide an increased amount of energy to a motor so that the motor may provide torque to a driveline for a longer period of time and/or absorb more vehicle generator produced power during vehicle operations.

Abstract: A method for extending the life cycle of a battery includes receiving a storage mode status signal at a battery controller and incrementally adjusting a state of charge window over a period of time in response to receiving the storage mode status 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: Systems and methods for operating a battery pack supplying power to propel a vehicle are disclosed. One example method comprises, adjusting a battery pack state of charge window in response to vehicle mass. Adjusting the battery pack state of charge window in response to vehicle mass may allow the battery pack to provide an increased amount of energy to a motor so that the motor may provide torque to a driveline for a longer period of time and/or absorb more vehicle generator produced power during vehicle operations.

Abstract: A vehicle includes a battery pack, an electric motor, and a contactor to electrically connect the pack and motor. The contactor is configured with a control circuit to electrically connect the pack and motor. The control circuit includes a leak detection sensor. The vehicle further includes a controller to output a leakage resistance associated with the pack. The leakage resistance is based on a voltage of the pack and a leak voltage detected by the sensor while the contactor is closed.

Abstract: Determination of an electric vehicle battery state-of-charge (SOC) based on measuring open circuit voltage is subject to error as the relationship changes over time. A method is provided for updating the relationship during aging. A charging current is applied to the battery cell. A favorable charging condition is detected in response to a predetermined charging current. A charging slope vector is compiled during the charging condition comprising a plurality of slope values over respective state-of-charge increments. A plurality of SOC-OCV slope vectors are determined corresponding to a plurality of stored SOC-OCV aging curves, each SOC-OCV slope vector comprising a plurality of slope values over equivalent state-of-charge increments. One of the stored SOC-OCV aging curves is selected having an SOC-OCV slope vector best fitting the charging slope vector for use in converting measured OCV values to battery cell SOC values.

Abstract: A vehicle may include a traction battery, a harness electrically connected with the battery, and a controller programmed to generate harness anomaly output based on data indicative of historical resistances associated with the harness and temperature and state of charge data for the battery indicative of a current resistance associated with the harness.

Abstract: Lithium ion battery state of charge (SOC) is a function of open circuit voltage (OCV). Battery internal diffusion process needs to be nearly completed to be able to measure battery open circuit voltage. The length of the minimum settling time depends on the battery type, usage and temperature. Described are methods to determine electric vehicle battery voltage relaxation time based on battery temperature and usage history.

Abstract: A leakage detection system for a battery pack of a vehicle may include detection circuitry having a first side connecting a positive terminal of the pack to ground and a second side connecting a negative terminal of the pack to ground, and including no more than one switch among the sides. The system may also include measurement circuitry configured to measure a voltage across a resistor of one of the sides when the switch is open and closed, and a controller programmed to output a leakage associated with the battery pack based on the voltage.

Abstract: A hybrid-electric vehicle includes a traction battery. A controller may operate the traction battery within certain state of charge and voltage limits. The controller may define a minimum operating voltage or state of charge below which no power may be requested from the traction battery. The minimum voltage and state of charge may be based on an electrical resistance of the traction battery. The voltage may also be based on a minimum power level required to crank the engine while meeting emissions standards. As the battery ages, the minimum voltage level may be adjusted such that the minimum power level is available at the minimum voltage level.

Abstract: A hybrid or electric vehicle includes a traction battery. A battery measurement diagnostic system compares a measured voltage and an estimated voltage. The estimated voltage is based on impedance parameter estimates and an equivalent circuit model of a battery. When a magnitude of a difference between the measured and estimated voltages is greater than a threshold, the impedance parameter estimates are based on impedance parameter estimates from a previous time step. If the magnitude exceeds the threshold for a predetermined number of time steps, a voltage measurement diagnostic flag is output. The logic minimizes the impact of voltage measurement spikes on estimated quantities and may indicate the condition to an operator.

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: An electric vehicle battery pack includes an array of battery cells each cell having an upper cell surface and a lower cell surface, the lower cell surface having a positive and a negative terminal; and a thermal assembly in thermally-conductive contact with the upper cell surfaces of the array. A battery pack cooling method is also disclosed.

Abstract: A method for extending the life cycle of a battery includes receiving a storage mode status signal at a battery controller and incrementally adjusting a state of charge window over a period of time in response to receiving the storage mode status signal.

Abstract: Systems and methods for operating a battery pack supplying power to propel a vehicle are disclosed. One example method comprises, determining a difference between an estimated battery pack temperature and a sensed battery pack temperature as a basis for adjusting battery pack output power. The method also includes adjusting a speed of a cooling fan based on the difference between estimated battery pack temperature and sensed battery pack temperature.