Abstract: Systems and methods for performing low voltage charging of a high voltage, series-connected string of battery modules are disclosed. A battery pack system may include a plurality of battery cells, including one or more groups of battery cells coupled in parallel. A processor may be configured to select a sub-group of battery cells from a group of battery cells for charging separately from other battery cells of the selected group of battery cells. The group of battery cells may be reconfigured to allow charging of the sub-group of battery cells separate from the other battery cells. The sub-group of battery cells may be charged, and then the group of battery cells may be reconfigured to allow operation of the sub-group of battery cells with the other battery cells. During charging, the sub-group of battery cells may be unavailable but other battery cells may continue to discharge.

Abstract: Systems and methods for performing low voltage charging of a high voltage, series-connected string of battery modules are disclosed. A battery pack system may include a plurality of battery cells, including one or more groups of battery cells coupled in parallel. A processor may be configured to select a sub-group of battery cells from a group of battery cells for charging separately from other battery cells of the selected group of battery cells. The group of battery cells may be reconfigured to allow charging of the sub-group of battery cells separate from the other battery cells. The sub-group of battery cells may be charged, and then the group of battery cells may be reconfigured to allow operation of the sub-group of battery cells with the other battery cells. During charging, the sub-group of battery cells may be unavailable but other battery cells may continue to discharge.

Abstract: A battery pack system module may include a module bypass switch for allowing charge current to bypass the battery pack system module. A charge switch and a discharge switch may be coupled with the module bypass switch. When other battery pack system modules are coupled in series with the module, balancing between modules may be achieved by allowing charge current to bypass the unbalanced modules and charge other modules. For example, when an unbalanced module is at a higher level of charge than other modules, a charge switch and a discharge switch in the unbalanced module de-activate and a module bypass switch activates to allow charge current to rapidly bring other modules into balance. The discharge switch and the charge switch allow the charging current to bypass the unbalanced module creating little or no additional heat dissipation.

Abstract: A battery pack system module may include a module bypass switch for allowing charge current to bypass the battery pack system module. The module bypass switch may be activated to divert charging current from the battery pack system module to other battery pack system modules. The charging current may be diverted to bring other battery pack system modules into balance with the battery pack system module. That is, to bring the state of charge of all battery pack system modules into coarse balance. When the module bypass switch is activated, charging current through the module bypass switch may be monitored by a current sensing device such as a current sensing resistor. A microprocessor may receive information about the bypass current level and use the information to determine when to de-activate the module bypass switch. Sensing current through a module bypass switch allows more accurate and quicker inter-module balancing.

Abstract: Battery cells may be monitored and a historical profile of the battery generated. The historical profile may be used to analyze a state-of-health of the battery cell. For example, the historical profile may be used to determine when a battery cell has developed an internal short that creates a safety hazard. The historical profile may include a count of the number of times the battery cell was out of balance and a count of the number of Coulombs the battery cell was out of balance. The number of Coulombs may be counted for a window of time. When the number of Coulombs exceeds a Coulomb threshold, a state-of-health flag may be set for the battery cell. The Coulomb threshold may be adjusted based, in part, on the counted number of times the battery cell is out of balance.

Abstract: Systems and methods for performing low voltage charging of a high voltage, series-connected string of battery modules are disclosed. A battery pack system may include a plurality of battery cells, including one or more groups of battery cells coupled in parallel. A processor may be configured to select a sub-group of battery cells from a group of battery cells for charging separately from other battery cells of the selected group of battery cells. The group of battery cells may be reconfigured to allow charging of the sub-group of battery cells separate from the other battery cells. The sub-group of battery cells may be charged, and then the group of battery cells may be reconfigured to allow operation of the sub-group of battery cells with the other battery cells. During charging, the sub-group of battery cells may be unavailable but other battery cells may continue to discharge.

Abstract: A battery pack system module may include a module bypass switch for allowing charge current to bypass the battery pack system module. The module bypass switch may be activated to divert charging current from the battery pack system module to other battery pack system modules. The charging current may be diverted to bring other battery pack system modules into balance with the battery pack system module. That is, to bring the state of charge of all battery pack system modules into coarse balance. When the module bypass switch is activated, charging current through the module bypass switch may be monitored by a current sensing device such as a current sensing resistor. A microprocessor may receive information about the bypass current level and use the information to determine when to de-activate the module bypass switch. Sensing current through a module bypass switch allows more accurate and quicker inter-module balancing.

Abstract: An apparatus and method are described for spreading heat, such as generated by an internal short, around battery cells when multiple battery cells are attached together in battery pack module. A tri-layer structure may be placed between battery cells, the tri-layer structure including heat spreading materials and an insulating material. The heat-spreading materials may be graphene sheets that preferentially conduct heat along one dimension. The insulating material may be polyimide. The tri-layer structure may transfer heat along a preferred direction to a location where the heat may be safely distributed or dissipated.

Abstract: A battery pack system module may include a module bypass switch for allowing charge current to bypass the battery pack system module. A charge switch and a discharge switch may be coupled with the module bypass switch. When other battery pack system modules are coupled in series with the module, balancing between modules may be achieved by allowing charge current to bypass the unbalanced modules and charge other modules. For example, when an unbalanced module is at a higher level of charge than other modules, a charge switch and a discharge switch in the unbalanced module de-activate and a module bypass switch activates to allow charge current to rapidly bring other modules into balance. The discharge switch and the charge switch allow the charging current to bypass the unbalanced module creating little or no additional heat dissipation.

Abstract: A system for balancing a plurality of battery pack system modules connected in series may include in each battery pack system module a controller configured to detect that the first system module has reached a first state of charge; activate the first charge switch to physically disconnect and to prevent further charging of the first system module after detecting the first state of charge; discharge the plurality of cells after activating the first charge switch to balance the first system module with a second system module coupled to the first system module; de-activate the first charge switch after discharging the plurality of battery cells; and charge the plurality of cells after de-activating the first charge switch.

Abstract: Failure mechanisms of a battery cell may be detected and prevented by monitoring a voltage of the battery cell, and detecting when the cell voltage falls below a voltage threshold. The length of time that the voltage remains below the voltage threshold may be monitored to detect when the length of time exceeds a time threshold. When the length of time has exceeded the time threshold, the battery pack may be disabled from further charging.

Abstract: Battery cells may be monitored and a historical profile of the battery generated. The historical profile may be used to analyze a state-of-health of the battery cell. For example, the historical profile may be used to determine when a battery cell has developed an internal short that creates a safety hazard. The historical profile may include a count of the number of times the battery cell was out of balance and a count of the number of Coulombs the battery cell was out of balance. The number of Coulombs may be counted for a window of time. When the number of Coulombs exceeds a Coulomb threshold, a state-of-health flag may be set for the battery cell. The Coulomb threshold may be adjusted based, in part, on the counted number of times the battery cell is out of balance.

Abstract: Battery cells may be monitored and a historical profile of the battery generated. The historical profile may be used to analyze a state-of-health of the battery cell. For example, the historical profile may be used to determine when a battery cell has developed an internal short that creates a safety hazard. The historical profile may include a count of the number of times the battery cell was out of balance and a count of the number of Coulombs the battery cell was out of balance. The number of Coulombs may be counted for a window of time. When the number of Coulombs exceeds a Coulomb threshold, a state-of-health flag may be set for the battery cell. The Coulomb threshold may be adjusted based, in part, on the counted number of times the battery cell is out of balance.

Abstract: A system for balancing a plurality of battery pack system modules connected in series may include in each battery pack system module a controller configured to detect that the first system module has reached a first state of charge; activate the first charge switch to physically disconnect and to prevent further charging of the first system module after detecting the first state of charge; discharge the plurality of cells after activating the first charge switch to balance the first system module with a second system module coupled to the first system module; de-activate the first charge switch after discharging the plurality of battery cells; and charge the plurality of cells after de-activating the first charge switch.

Abstract: A system for balancing a plurality of battery pack system modules connected in series comprising: a plurality of battery pack system modules, wherein a high charge module of the plurality of battery pack system modules has a charge greater than a that of other modules. At least one zener diode connected in series with a current limiting resistor is connected in parallel to the plurality of battery pack system modules. A power source is in communication with a disconnect circuit of at least one of the battery pack system modules. The disconnect circuit is actuated when the battery pack system module reaches a predetermined state of charge. The zener diode enables current from the power source to bypass charged battery pack system modules to charge other battery pack system modules.

Abstract: A system for balancing a plurality of battery pack system modules connected in series comprising: a plurality of battery pack system modules, wherein a high charge module of the plurality of battery pack system modules has a charge greater than a that of other modules. At least one zener diode connected in series with a current limiting resistor is connected in parallel to the plurality of battery pack system modules. A power source is in communication with a disconnect circuit of at least one of the battery pack system modules. The disconnect circuit is actuated when the battery pack system module reaches a predetermined state of charge. The zener diode enables current from the power source to bypass charged battery pack system modules to charge other battery pack system modules.

Abstract: A system for balancing a plurality of battery pack system modules connected in series comprising: a plurality of battery pack system modules, wherein a high charge module of the plurality of battery pack system modules has a charge greater than a that of other modules. At least one zener diode connected in series with a current limiting resistor is connected in parallel to the plurality of battery pack system modules. A power source is in communication with a disconnect circuit of at least one of the battery pack system modules. The disconnect circuit is actuated when the battery pack system module reaches a predetermined state of charge. The zener diode enables current from the power source to bypass charged battery pack system modules to charge other battery pack system modules.

Abstract: A system for balancing a plurality of battery pack system modules connected in series comprising: a plurality of battery pack system modules, wherein a high charge module of the plurality of battery pack system modules has a charge greater than a that of other modules. At least one zener diode connected in series with a current limiting resistor is connected in parallel to the plurality of battery pack system modules. A power source is in communication with a disconnect circuit of at least one of the battery pack system modules. The disconnect circuit is actuated when the battery pack system module reaches a predetermined state of charge. The zener diode enables current from the power source to bypass charged battery pack system modules to charge other battery pack system modules.

Abstract: A battery pack control module for balancing a plurality of lithium secondary cells or groups of lithium secondary cells connected in series and method of use.

Abstract: A battery pack control module for balancing a plurality of lithium secondary cells or groups of lithium secondary cells connected in series and method of use.