Southwest Electronic Energy Corporation

David Allen White

Claude Leonard Benckenstein, Jr

Jeffrey Johnson

Claude Leonard Benckenstein

Brett Levins

Claude Leonard Beckenstein

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.

Low voltage charging of a high voltage, series-connected string of battery modules

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.

Initializer-based control of a module bypass switch for balancing of battery pack system modules

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.

Module bypass switch for balancing battery pack system modules with bypass current monitoring

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.

Historical analysis of battery cells for determining state of health

Module bypass switch with bypass current monitoring

Module bypass switch for balancing battery pack system modules

Internal shorts and other failures in lithium-ion battery cells may be detected during balancing of the battery cells. A counter may be used to detect when a battery cell is behaving differently than other battery cells by balancing more or less frequently. The counter may increment each time a battery cell is balanced to the other battery cells. A misbehaving battery cell may be flagged, when the counter exceeds a threshold value, for safety checks before an overheating event occurs. This misbehaving battery cell may be faulty due to an internal short. If the faulty battery cell is not corrected by replacement with a different battery cell or corrected by a user resetting the counter, the misbehaving battery cell may be disconnected to prevent the overheating event.

Short detection in battery cells

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.

Balancing of battery pack system modules

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.

Balancing charge between battery pack system modules in a battery

System for balancing a plurality of battery pack system modules connected in series

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.

Method for balancing lithium secondary cells and modules

A method for balancing cells or groups of cells connected in parallel and in series for a battery pack by providing a continuously balanced state of charge while in a discharge phase, a charge phase, a quiescent phase, a storage phase, or combinations of these phases.

Method for balancing cells or groups of cells in a battery pack

A battery pack control module for balancing a plurality of cells or groups of cells connected in series includes a controller assembly, a disconnect circuit, a pack sensing circuit, a balancing circuit, and computer instructions for instructing the controller assembly to control the disconnect circuit and the balancing circuit. The disconnect circuit engages the controller assembly and a plurality of cells or groups of cells connected in series. The pack sensing circuit connects to the controller assembly and the plurality of cells or groups of cells connected in series. The balancing circuit connects between the plurality of cells or groups of cells connected in series, and engages the controller assembly. The plurality of cells or groups of cells connected in series is balanced when the battery pack control module operates in a charging phase, a discharging phase, a quiescent phase, or a storage phase.

Battery pack control module

A method for extending the power duration of lithium ion cells or groups of lithium ion cells connected in parallel and in series by providing a continuously balanced state of charge while in a discharge phase, a charge phase, a quiescent phase, a storage phase, or combinations of these phases.

Growing community of inventors

Houston, TX, United States of America

David Allen White