Abstract: A system and method for estimating internal parameters of a lithium-ion battery to provide a reliable battery state-of-charge estimate. The method uses a two RC-pair equivalent battery circuit model to estimate the battery parameters, including a battery open circuit voltage, an ohmic resistance, a double layer capacitance, a charge transfer resistance, a diffusion resistance and a diffusion capacitance. The method further uses the equivalent circuit model to provide a difference equation from which the battery parameters are adapted, and calculates the battery parameters from the difference equation.

Abstract: Methods and systems for dynamically estimating the core temperature of at least one cell in a battery. In one aspect, the method includes using a combination of estimations including one based on ohmic resistance and another based on a function of thermal energy transfer through the battery. A weighting factor may be used for each of the estimations as a way to calculating a core temperature. The estimation based on ohmic resistance may be made determined independently of a measured surface temperature of the battery or any of the cells in the battery.

Abstract: A system and method for use with a vehicle battery pack having a number of individual battery cells, such as a lithium-ion battery commonly used in hybrid electric vehicles. In one embodiment, the method evaluates individual battery cells within a vehicle battery pack in order to obtain accurate estimates regarding their average transient voltage effect, open circuit voltage (OCVCell) and/or state of charge (SOCCell) so that a cell balancing process can be performed. These cell evaluations may be performed fairly soon after the vehicle is turned off and in a manner that utilizes a minimal amount of in-vehicle resources.

Abstract: Methods and systems for dynamically estimating the core temperature of at least one cell in a battery. In one aspect, the method includes using a combination of estimations including one based on ohmic resistance and another based on a function of thermal energy transfer through the battery. A weighting factor may be used for each of the estimations as a way to calculating a core temperature. The estimation based on ohmic resistance may be made determined independently of a measured surface temperature of the battery or any of the cells in the battery.

Abstract: A system and method for estimating internal parameters of a lithium-ion battery to provide a reliable battery state-of-charge estimate. The method uses a two RC-pair equivalent battery circuit model to estimate the battery parameters, including a battery open circuit voltage, an ohmic resistance, a double layer capacitance, a charge transfer resistance, a diffusion resistance and a diffusion capacitance. The method further uses the equivalent circuit model to provide a difference equation from which the battery parameters are adapted, and calculates the battery parameters from the difference equation.

Abstract: A system and method for use with a vehicle battery pack having a number of individual battery cells, such as a lithium-ion battery commonly used in hybrid electric vehicles. In one embodiment, the method evaluates individual battery cells within a vehicle battery pack in order to obtain accurate estimates regarding their average transient voltage effect, open circuit voltage (OCVCell) and/or state of charge (SOCCell) so that a cell balancing process can be performed. These cell evaluations may be performed fairly soon after the vehicle is turned off and in a manner that utilizes a minimal amount of in-vehicle resources.