Abstract: A system for determining a discharge power limit value of a battery cell is provided. A microprocessor calculates an adjusted maximum allowed voltage drop value based on a maximum allowed voltage drop value, and an estimated delta OCV value at N seconds after a first time. The estimated delta OCV value is calculated based on a first discharge current level. The microprocessor calculates a second discharge current level through the battery cell for N seconds to obtain the adjusted maximum allowed voltage drop value. The microprocessor calculates a discharge power limit value based on the second discharge current level that indicates an amount of power from the battery cell for N seconds without the voltage across the battery cell falling below a minimum allowed voltage of the battery cell.

Abstract: A battery monitoring system includes a current sensor and a voltage sensor coupled to a battery cell. It also includes a microcontroller that opportunistically computes many estimates of the cell's ohmic resistance and filters these estimates to arrive at a stable value. Each estimate is traditionally computed from a delta change in voltage divided by delta change in current measured before and after a significant change in current magnitude. An improvement in accuracy of each resistance estimate is achieved by only computing an estimate if the rate of change of voltage and the rate of change of current exhibited by the values making up the delta voltage and delta current are tightly consistent and of the same polarity. This approach significantly minimizes errors induced in estimates not preselected in this manner by the different and also asynchronous sample rates of the cell's voltage and current.

Abstract: A system for determining a discharge power limit value of a battery cell is provided. A microprocessor calculates an adjusted maximum allowed voltage drop value based on a maximum allowed voltage drop value, and an estimated delta OCV value at N seconds after a first time. The estimated delta OCV value is calculated based on a first discharge current level. The microprocessor calculates a second discharge current level through the battery cell for N seconds to obtain the adjusted maximum allowed voltage drop value. The microprocessor calculates a discharge power limit value based on the second discharge current level that indicates an amount of power from the battery cell for N seconds without the voltage across the battery cell falling below a minimum allowed voltage of the battery cell.

Abstract: A battery monitoring system includes a current sensor and a voltage sensor coupled to a battery cell. It also includes a microcontroller that opportunistically computes many estimates of the cell's ohmic resistance and filters these estimates to arrive at a stable value. Each estimate is traditionally computed from a delta change in voltage divided by delta change in current measured before and after a significant change in current magnitude. An improvement in accuracy of each resistance estimate is achieved by only computing an estimate if the rate of change of voltage and the rate of change of current exhibited by the values making up the delta voltage and delta current are tightly consistent and of the same polarity. This approach significantly minimizes errors induced in estimates not preselected in this manner by the different and also asynchronous sample rates of the cell's voltage and current.

Abstract: A system for determining a discharge power limit value and a charge power limit of the battery cell is provided. The system has a microprocessor that calculates a maximum allowed voltage drop value of the battery cell. The microprocessor calculates a first current level through the battery cell for a predetermined amount of time to obtain the maximum allowed voltage drop value. The microprocessor calculates a first discharge power limit value, if the first current level is less than or equal to a maximum allowed discharge current. The microprocessor calculates a second discharge power limit value, if the first current level is greater than the maximum allowed discharge current.

Abstract: A system for determining a discharge power limit value and a charge power limit of the battery cell is provided. The system has a microprocessor that calculates a maximum allowed voltage drop value of the battery cell. The microprocessor calculates a first current level through the battery cell for a predetermined amount of time to obtain the maximum allowed voltage drop value. The microprocessor calculates a first discharge power limit value, if the first current level is less than or equal to a maximum allowed discharge current. The microprocessor calculates a second discharge power limit value, if the first current level is greater than the maximum allowed discharge current.