Abstract: A method for managing a plurality of batteries that are electrically coupled together includes (1) monitoring respective voltages of the plurality of batteries and (2) in response to a respective voltage of a first battery of the plurality of batteries reaching a first threshold value at a first time, reducing a charge or discharge rate of the first battery, relative to at least a second battery of the plurality of batteries. Charge and discharge rates may be adaptively managed such that each battery reaches the first threshold value at substantially the same time.

Abstract: A battery stack includes a plurality of battery management system (BMS) nodes and a controller. Each BMS node includes a battery, an isolation switch configured to selectably isolate the battery of the BMS node from the batteries of the other BMS nodes, and a bypass switch configured to selectably provide a path for electrical current flowing through the battery stack to bypass the battery of the BMS node. The batteries of the BMS nodes are electrically coupled in series. The controller is configured to control the isolation switch and the bypass switch of each BMS node such that the battery of each BMS node can be individually connected to and disconnected from an electrical power source/sink.

Abstract: A method for managing a plurality of batteries that are electrically coupled together includes (1) monitoring respective voltages of the plurality of batteries and (2) in response to a respective voltage of a first battery of the plurality of batteries reaching a first threshold value at a first time, reducing a charge or discharge rate of the first battery, relative to at least a second battery of the plurality of batteries. Charge and discharge rates may be adaptively managed such that each battery reaches the first threshold value at substantially the same time.

Abstract: A battery stack includes a plurality of battery management system (BMS) nodes and a controller. Each BMS node includes a battery, an isolation switch configured to selectably isolate the battery of the BMS node from the batteries of the other BMS nodes, and a bypass switch configured to selectably provide a path for electrical current flowing through the battery stack to bypass the battery of the BMS node. The batteries of the BMS nodes are electrically coupled in series. The controller is configured to control the isolation switch and the bypass switch of each BMS node such that the battery of each BMS node can be individually connected to and disconnected from an electrical power source/sink.

Abstract: Described methods and systems are used for in-situ impedance spectroscopy analysis of battery cells in multi-cell battery packs. Specifically, the cell impedances are determined while the pack continues to operate, such as being charged or discharged. For example, the pack voltage/power output remains unchanged while this analysis is initiated, performed, and ended. Cell impedance is determined based on the cell's response to the signal applied to the cell. For example, a current through the cell is charged while monitoring cells' voltage response. Although the power output of the changes during this testing, but the operation of the pack is not impacted due to the power compensation provided by one or more other cells in the pack thereby ensuring uninterrupted operation of the pack. This in situ testing is provided by the unique architecture of the pack, comprising multiple nodes and individual node controllers.

Abstract: Described methods and systems provide in-situ leakage current testing of battery cells in battery packs even while these packs operate. Specifically, an external electrical current is discontinued through a tested battery cell using a node controller, to which the tested battery cell is independently connected. Changes in the open circuit voltage (OCV) are then detected by the node controller for a set period time. Any voltage change, associated with taking the tested cell offline, is compensated by one or more other cells in the battery pack. The overall pack current and voltage remains substantially unchanged (based on the application demands), while the in-situ leakage current testing is initiated, performed, and/or completed. The OCV changes are then used to determine the leakage current of the tested cell and, in some examples, to determine the state of health of this cell and/or adjust the operating parameters of this cell.

Abstract: A system and method for hierarchical arc fault monitoring in an energy storage system, where the energy storage system includes a plurality of stacks that are electrically coupled together. Each stack includes a plurality of battery management system nodes that are electrically coupled together. The method includes (1) obtaining respective electrical measurement values for each stack; (2) determining, for each stack, that the stack is free of arc faults, using the respective electrical measurement values for the stack; (3) obtaining electrical measurement values for the energy storage system; and (4) determining that the energy storage system is free of arc faults outside of the plurality of stacks, using (a) the electrical measurement values for the energy storage system and (b) a subset of the respective electrical measurement values for each stack.

Abstract: A method for managing a plurality of stacks of electrochemical cells, where the plurality of stacks are electrically coupled in parallel in a battery. The method includes (a) operating the plurality of stacks to execute a global operating strategy of the battery, (b) changing respective operating points of one or more first stacks of the plurality of stacks to execute a local operating strategy, (c) changing respective operating points of one or more second stacks of the plurality of stacks to maintain the global operating strategy of the battery while executing the local operating strategy, and (d) after completing execution of the local operating strategy, further changing the respective operating points of the one or more first stacks to compensate for change in the state of charge of the one or more first stacks caused by executing the local operating strategy.

Abstract: A method for managing a plurality of stacks of electrochemical cells, where the plurality of stacks are electrically coupled in parallel in a battery. The method includes (a) operating the plurality of stacks to execute a global operating strategy of the battery, (b) changing respective operating points of one or more first stacks of the plurality of stacks to execute a local operating strategy, and (c) changing respective operating points of one or more second stacks of the plurality of stacks to maintain the global operating strategy of the battery while executing the local operating strategy.

Abstract: Described methods and systems provide in-situ leakage current testing of battery cells in battery packs even while these packs operate. Specifically, an external electrical current is discontinued through a tested battery cell using a node controller, to which the tested battery cell is independently connected. Changes in the open circuit voltage (OCV) are then detected by the node controller for a set period time. Any voltage change, associated with taking the tested cell offline, is compensated by one or more other cells in the battery pack. The overall pack current and voltage remains substantially unchanged (based on the application demands), while the in-situ leakage current testing is initiated, performed, and/or completed. The OCV changes are then used to determine the leakage current of the tested cell and, in some examples, to determine the state of health of this cell and/or adjust the operating parameters of this cell.

Abstract: Described methods and systems are used for in-situ impedance spectroscopy analysis of battery cells in multi-cell battery packs. Specifically, the cell impedances are determined while the pack continues to operate, such as being charged or discharged. For example, the pack voltage/power output remains unchanged while this analysis is initiated, performed, and ended. Cell impedance is determined based on the cell's response to the signal applied to the cell. For example, a current through the cell is charged while monitoring cells' voltage response. Although the power output of the changes during this testing, but the operation of the pack is not impacted due to the power compensation provided by one or more other cells in the pack thereby ensuring uninterrupted operation of the pack. This in situ testing is provided by the unique architecture of the pack, comprising multiple nodes and individual node controllers.

Abstract: A method for determining a temperature characteristic of an electrochemical cell assembly includes (1) sensing a first voltage via one or more thermistors electrically coupled to the electrochemical cell assembly while loading circuitry electrically coupled to the thermistors is deactivated, (2) sensing a second voltage via the one or more thermistors while the loading circuitry is activated, and (3) determining the temperature characteristic of the electrochemical cell assembly at least partially from the first and second voltages.

Abstract: A method for managing a plurality of batteries that are electrically coupled together includes (1) monitoring respective voltages of the plurality of batteries and (2) in response to a respective voltage of a first battery of the plurality of batteries reaching a first threshold value at a first time, reducing a charge or discharge rate of the first battery, relative to at least a second battery of the plurality of batteries. Charge and discharge rates may be adaptively managed such that each battery reaches the first threshold value at substantially the same time.

Abstract: A system and method for hierarchical arc fault monitoring in an energy storage system, where the energy storage system includes a plurality of stacks that are electrically coupled together. Each stack includes a plurality of battery management system nodes that are electrically coupled together. The method includes (1) obtaining respective electrical measurement values for each stack; (2) determining, for each stack, that the stack is free of arc faults, using the respective electrical measurement values for the stack; (3) obtaining electrical measurement values for the energy storage system; and (4) determining that the energy storage system is free of arc faults outside of the plurality of stacks, using (a) the electrical measurement values for the energy storage system and (b) a subset of the respective electrical measurement values for each stack.

Abstract: A battery stack includes a plurality of battery management system (BMS) nodes and a controller. Each BMS node includes a battery, an isolation switch configured to selectably isolate the battery of the BMS node from the batteries of the other BMS nodes, and a bypass switch configured to selectably provide a path for electrical current flowing through the battery stack to bypass the battery of the BMS node. The batteries of the BMS nodes are electrically coupled in series. The controller is configured to control the isolation switch and the bypass switch of each BMS node such that the battery of each BMS node can be individually connected to and disconnected from an electrical power source/sink.

Abstract: A method for determining a temperature characteristic of an electrochemical cell assembly includes (1) sensing a first voltage via one or more thermistors electrically coupled to the electrochemical cell assembly while loading circuitry electrically coupled to the thermistors is deactivated, (2) sensing a second voltage via the one or more thermistors while the loading circuitry is activated, and (3) determining the temperature characteristic of the electrochemical cell assembly at least partially from the first and second voltages.

Abstract: Described methods and systems are used for in-situ impedance spectroscopy analysis of battery cells in multi-cell battery packs. Specifically, the cell impedances are determined while the pack continues to operate, such as being charged or discharged. For example, the pack voltage/power output remains unchanged while this analysis is initiated, performed, and ended. Cell impedance is determined based on the cell's response to the signal applied to the cell. For example, a current through the cell is charged while monitoring cells' voltage response. Although the power output of the changes during this testing, but the operation of the pack is not impacted due to the power compensation provided by one or more other cells in the pack thereby ensuring uninterrupted operation of the pack. This in situ testing is provided by the unique architecture of the pack, comprising multiple nodes and individual node controllers.

Abstract: Described methods and systems provide in-situ leakage current testing of battery cells in battery packs even while these packs operate. Specifically, an external electrical current is discontinued through a tested battery cell using a node controller, to which the tested battery cell is independently connected. Changes in the open circuit voltage (OCV) are then detected by the node controller for a set period time. Any voltage change, associated with taking the tested cell offline, is compensated by one or more other cells in the battery pack. The overall pack current and voltage remains substantially unchanged (based on the application demands), while the in-situ leakage current testing is initiated, performed, and/or completed. The OCV changes are then used to determine the leakage current of the tested cell and, in some examples, to determine the state of health of this cell and/or adjust the operating parameters of this cell.

Abstract: A system and method for hierarchical arc fault monitoring in an energy storage system, where the energy storage system includes a plurality of stacks that are electrically coupled together. Each stack includes a plurality of battery management system nodes that are electrically coupled together. The method includes (1) obtaining respective electrical measurement values for each stack; (2) determining, for each stack, that the stack is free of arc faults, using the respective electrical measurement values for the stack; (3) obtaining electrical measurement values for the energy storage system; and (4) determining that the energy storage system is free of arc faults outside of the plurality of stacks, using (a) the electrical measurement values for the energy storage system and (b) a subset of the respective electrical measurement values for each stack.

Abstract: Described methods and systems provide in-situ leakage current testing of battery cells in battery packs even while these packs operate. Specifically, an external electrical current is discontinued through a tested battery cell using a node controller, to which the tested battery cell is independently connected. Changes in the open circuit voltage (OCV) are then detected by the node controller for a set period time. Any voltage change, associated with taking the tested cell offline, is compensated by one or more other cells in the battery pack. The overall pack current and voltage remains substantially unchanged (based on the application demands), while the in-situ leakage current testing is initiated, performed, and/or completed. The OCV changes are then used to determine the leakage current of the tested cell and, in some examples, to determine the state of health of this cell and/or adjust the operating parameters of this cell.