Abstract: A battery management system for managing the voltage of a battery cell, such as a lithium ion battery, is disclosed. The battery management system comprises a semiconductor switch coupled to the battery cell, wherein the semiconductor switch is in an on condition when the voltage across the battery cell exceeds a first threshold voltage, and a microprocessor coupled to the semiconductor switch, wherein the microprocessor monitors the voltage across the battery cell when the semiconductor switch is on, and turns itself off when the when the monitored voltage is less than a second threshold voltage, thereby preventing further current drain from the battery cell.

Abstract: A lithium iron phosphate battery pack is disclosed. The battery pack includes a plurality of battery cells, arranged as groups of cells, a controller circuit, and a plurality of intercell tabs coupling the groups of battery cells to the controller circuit. The controller circuit includes a voltage sensor for monitoring the voltage across each of the groups of cells. If one of the groups has a voltage that is lower or higher than a respective lower or upper threshold voltage, the controller circuit will shut off the charge/discharge cycling of all the groups of cells. In doing so, the controller circuit protects the entire battery pack during charge/discharge cycling.

Abstract: For a circuit for preventing overcharging of a battery cell, the overcharging protecting circuit having a voltage detector for monitoring the voltage across the battery cell, a polarity protection circuit for protecting the voltage detector from a reverse polarity connection of the battery cell to the voltage detector is disclosed. The polarity protection circuit comprises a semiconductor device coupled across voltage detection inputs of the voltage detector. The semiconductor device is adapted to shunt current across the voltage detection inputs of the voltage detector when the battery cell is connected in reverse polarity to the voltage detector.

Abstract: A circuit for preventing overcharging a battery cell is disclosed. The circuit comprises a voltage detector for monitoring a voltage across a battery cell. The voltage detector is configured to determine when the voltage across the battery cell is greater than a first threshold voltage. The circuit further comprises an electronic switch responsive to the voltage detector and is configured to shunt current around the battery cell when the voltage detector has determined the battery cell voltage is greater than the first threshold voltage.

Abstract: A battery management system for managing the voltage of a battery cell, such as a lithium ion battery, is disclosed. The battery management system comprises a semiconductor switch coupled to the battery cell, wherein the semiconductor switch is in an on condition when the voltage across the battery cell exceeds a first threshold voltage, and a microprocessor coupled to the semiconductor switch, wherein the microprocessor monitors the voltage across the battery cell when the semiconductor switch is on, and turns itself off when the when the monitored voltage is less than a second threshold voltage, thereby preventing further current drain from the battery cell.

Abstract: A lithium ion battery pack including a housing and a top attached to an open end of the housing is disclosed. The battery pack includes plurality of battery cells, arranged in parallel and contained in the housing. The battery pack further includes cathode and anode current collectors. Each of the current collectors includes a collector plate welded to a collector plate tab. The collector plate tabs are welded to the respective cathode and anode covers of the battery cells.