A safe battery energy management system, battery management system node and method

Abstract

A battery pack includes a plurality of battery management system (BMS) nodes and a controller. Each BMS node includes a battery, an isolation switch configured to selectively isolate the battery of the BMS node from the batteries of other BMS nodes, and a bypass switch configured to selectively provide a path for current flow through the battery pack 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 a power source / sink.

Description

Background Technology

[0001] A battery stack, or arrangement of multiple battery devices connected together, serves as a power source in a wide range of devices. A battery management system (BMS) is used to maintain individual battery devices within the stack within their safe operating range by monitoring physical quantities such as charging, current, voltage, and temperature. Based on these quantities, not only can the battery devices be operated safely, but their state of charge (SOC) and health status can also be determined. The BMS also performs cell balancing. Individual battery cells can be arranged in parallel and series within a battery stack to achieve the desired capacity and operating voltage. Battery manufacturers attempt to provide stacks with identical battery cells, but this is often physically impossible. Even with precise manufacturing and selection of battery cells, cells typically exhibit at least slight differences from one another. Any capacity mismatch between battery cells within a stack results in a reduction in the overall stack capacity. Even small differences can lead to varying charge or discharge levels, where the weakest cell in the stack disproportionately affects the overall stack performance. Energy management systems are also used for battery cell balancing, which involves techniques that balance the voltage and state of charge between battery cells when the cells are fully charged. Summary of the Invention

[0002] In a first aspect, a method for hierarchical arc fault monitoring in an energy storage system, the energy storage system comprising a plurality of battery stacks electrically interconnected, wherein each battery stack comprises a plurality of battery management system nodes electrically interconnected, the method comprising the steps of: (1) obtaining individual electrical measurements for each battery stack; (2) for each battery stack, determining that the battery stack is free from arc faults, using the individual electrical measurements of the battery stack; (3) obtaining electrical measurements for the energy storage system; and (4) determining that the energy storage system is free from arc faults outside the plurality of battery stacks, using (a) the electrical measurements of the energy storage system and (b) a subset of the individual electrical measurements of each battery stack.

[0003] In an embodiment of the first aspect, the method further includes: obtaining individual electrical measurements for each stack and electrical measurements for the energy storage system during a common time period.

[0004] In another embodiment of the first aspect, obtaining the respective electrical measurements for each battery stack includes, for the first battery stack among a plurality of battery stacks: (1) sending a measurement command to each battery management system node of the first battery stack; and (2) simultaneously acquiring one or more respective electrical measurements for each battery management system node of the first battery stack at a common time specified by the measurement command.

[0005] In another embodiment of the first aspect, the method further includes: propagating electrical measurement values ​​for the first node of the plurality of battery management system nodes through at least one other node of the plurality of battery management system nodes.

[0006] In another embodiment of the first aspect, obtaining the respective electrical measurement values ​​for each battery stack includes, for the first battery stack among a plurality of battery stacks: (1) sending a measurement command to each battery management system node of the first battery stack; at each battery management system node of the first battery stack, retrieving one or more stored electrical measurement values ​​corresponding to the time specified by the measurement command from the storage of the battery management system node.

[0007] In another embodiment of the first aspect, the method further includes: in response to the sum of voltages across each battery management system node of the stack being consistent with the measured voltages across the stack, determining, for each stack, that the stack is free from series arcing faults.

[0008] In another embodiment of the first aspect, the method further includes: (1) determining, in response to a mismatch between the sum of the voltages across each battery management system node of the first stack and the measured voltages across the first stack, that a series arcing fault has occurred in the first stack of the plurality of stacks; and (2) in response to determining that a series arcing fault has occurred in the first stack, switching the first stack from an operating mode to a float charge mode by isolating the individual batteries in each battery management system node of the first stack.

[0009] In another embodiment of the first aspect, the method further includes: determining that the energy storage system has no series arcing fault outside the plurality of stacks in response to the measured voltage at both ends of a load electrically connected to the energy storage system being consistent with the respective measured voltage at both ends of each stack.

[0010] In another embodiment of the first aspect, the load is capable of both receiving power from the energy storage system and supplying power to the energy storage system.

[0011] In another embodiment of the first aspect, the method further includes: determining, in response to a mismatch between a measured voltage across the load and a measured voltage across the first stack, that an arc fault has occurred in series with the first stack among a plurality of stacks.

[0012] In another embodiment of the first aspect, the method further includes: in response to determining that an arc fault has occurred in series with the first battery stack, switching the first battery stack from an operating mode to a float charge mode by isolating the first battery stack from the remaining battery stacks among a plurality of battery stacks.

[0013] In another embodiment of the first aspect, the method further includes: in response to determining that an arc fault has occurred in series with the first fuel cell, switching the first fuel cell from an operating mode to a safe mode by reducing one or more of the voltage and current of the first fuel cell.

[0014] In another embodiment of the first aspect, the method further includes: in response to the fact that a measured current flowing through each battery management system node of the stack is consistent with a measured current flowing through the stack, determining, for each stack, that the stack has no parallel arcing fault.

[0015] In another embodiment of the first aspect, the method further includes: in response to a mismatch between the currents flowing through the two battery management system nodes of the first stack, determining, for the first stack among a plurality of stacks, that a parallel arc has occurred between the two battery management system nodes of the first stack.

[0016] In another embodiment of the first aspect, the method further includes: in response to determining that a parallel arcing fault has occurred between two battery management system nodes of the first battery stack, switching the first battery stack from an operating mode to a float charge mode by isolating the individual batteries in each battery management system node of the first battery stack.

[0017] In another embodiment of the first aspect, the method further includes: determining that the energy storage system has no parallel arcing fault outside the plurality of stacks in response to a measured current of a load electrically connected to the energy storage system being consistent with a measured current flowing through each stack.

[0018] In another embodiment of the first aspect, the method further includes: in response to determining that a parallel arcing fault has occurred in a battery management system outside the plurality of stacks, switching each stack from an operating mode to a safe mode by reducing one or more of the respective voltages and currents of each stack.

[0019] In another embodiment of the first aspect, the method further includes: (1) removing power transfer switch noise and associated harmonics from individual electrical measurements of each stack before determining that the stack is free from arc faults; and (2) removing power transfer switch noise and associated harmonics from electrical measurements of the energy storage system before determining that the energy storage system is free from arc faults outside the plurality of stacks.

[0020] In another embodiment of the first aspect, (1) a first low-pass filter is used to remove power transfer switching noise and associated harmonics from the various electrical measurements of each stack; (2) a second low-pass filter is used to remove power transfer switching noise and associated harmonics from the electrical measurements of the energy storage system; and (3) the first low-pass filter and the second low-pass filter have substantially the same bandwidth.

[0021] In a second aspect, the energy storage system includes: (1) a plurality of battery stacks electrically connected together, each battery stack including a plurality of battery management system nodes electrically connected together; and (2) a control subsystem configured to (1) obtain individual electrical measurements of each battery stack, (2) determine, for each battery stack, using the individual electrical measurements of the battery stack, that the battery stack is free from arcing faults, (3) obtain electrical measurements of the energy storage system, and (4) determine that the energy storage system is free from arcing faults outside the plurality of battery stacks, using (i) the electrical measurements of the energy storage system and (ii) a subset of the individual electrical measurements of each battery stack.

[0022] In a second aspect of the implementation, the control subsystem is further configured to: determine, for each stack, that there is no series arcing fault in the stack in response to the sum of the voltages across each battery management system node of the stack being consistent with the measured voltages across the stack.

[0023] In another embodiment of the second aspect, the control subsystem is further configured to determine that there is no series arcing fault outside the multiple stacks of energy storage system in response to the measured voltage at both ends of the load connected to the energy storage system being consistent with the respective measured voltage at both ends of each stack.

[0024] In another embodiment of the second aspect, the control subsystem is further configured to: determine, for each stack, that there is no parallel arcing fault in the stack in response to the fact that each measured current flowing through each battery management system node of the stack is consistent with the measured current flowing through the stack.

[0025] In another embodiment of the second aspect, the control subsystem is further configured to determine that the energy storage system has no parallel arcing fault outside the multiple stacks, in response to the fact that the measured current of the load connected to the energy storage system via electrical connection is consistent with the measured current flowing through each stack.

[0026] In a third aspect, a method for managing an energy storage system, the energy storage system comprising a stack of multiple battery management system nodes electrically interconnected, the method comprising the following steps:

[0027] (1) Send a measurement command to each battery management system node; (2) In response to the measurement command, at each battery management system node, obtain one or more individual electrical measurements of the battery management system node, each of the one or more individual electrical measurements of the battery management system node corresponding to the time specified in the measurement command; and (3) Use the one or more individual electrical measurements of each battery management system node to manage at least one aspect of the energy storage system.

[0028] In a third aspect of the implementation, the method further includes: simultaneously obtaining one or more individual electrical measurement values ​​for each battery management system node.

[0029] In another embodiment of the third aspect, the method further includes: propagating the electrical measurement value of the first node of the plurality of battery management system nodes through at least one other node of the plurality of battery management system nodes.

[0030] In another embodiment of the third aspect, the method further includes obtaining one or more electrical measurement values ​​of each battery management system node from the respective storage devices of the battery management system node.

[0031] In another implementation of the third aspect, at least one aspect of managing the energy storage system includes: using one or more individual electrical measurements of each battery management system node to determine that the stack is free from arcing faults.

[0032] In another embodiment of the third aspect, the method further includes: determining that the battery stack has no series arcing fault in response to the sum of the voltages across each battery management system node being consistent with the measured voltages across the battery stack.

[0033] In another embodiment of the third aspect, the method further includes: determining that the battery stack has no parallel arcing fault in response to the fact that each measured current flowing through each battery management system node is consistent with a measured current flowing through the battery stack.

[0034] In another embodiment of the third aspect, at least one aspect of managing the energy storage system includes: controlling at least one of the charging and discharging of individual batteries of a plurality of battery management system nodes.

[0035] In a fourth aspect, an energy storage system includes: (1) a battery stack including a plurality of battery management system nodes electrically connected together, each battery management system node being configured to obtain one or more individual electrical measurements of the battery management system node in response to a measurement command, each of the one or more individual electrical measurements of the battery management system node corresponding to a time specified by the measurement command; and (2) a control subsystem configured to: (a) send a measurement command to each battery management system node, and (b) use one or more individual electrical measurements of each battery management system node to manage at least one aspect of the energy storage system.

[0036] In an implementation of the fourth aspect, the control subsystem is further configured to manage at least one aspect of the energy storage system by determining that the stack is free from arcing faults, using one or more individual electrical measurements from each battery management system node.

[0037] In another embodiment of the fourth aspect, the control subsystem is further configured to manage at least one aspect of the energy storage system by controlling at least one of the charging and discharging of individual batteries of a plurality of battery management system nodes.

[0038] In a fifth aspect, a method for addressing an arc fault in an energy storage system, the energy storage system comprising a stack of batteries of a plurality of battery management system nodes electrically connected together, the method comprising the steps of: (1) determining that an arc fault has occurred in the stack; and (2) in response to determining that an arc fault has occurred in the stack, at least partially electrically isolating each battery of each battery management system node by disconnecting the respective isolating switches electrically connected to the batteries.

[0039] In a fifth aspect of the implementation, the method further includes: in response to determining that an arcing fault has occurred in the battery stack, enabling the battery stack to operate in float charge mode by causing the node output short-circuit switches electrically connected to both ends of the output port of each battery management system node to operate in their off state.

[0040] In another embodiment of the fifth aspect, the arc fault in the fuel cell stack is a series arc fault in the fuel cell stack, and the method further includes: (1) obtaining electrical measurements of the fuel cell stack; and (2) determining, in response to a mismatch between the sum of voltages across each battery management system node of the fuel cell stack and the measured voltages across the fuel cell stack, that a series arc fault has occurred in the fuel cell stack.

[0041] In another embodiment of the fifth aspect, the method further includes: (1) sending a measurement command to each battery management system node; and (2) in response to the measurement command, obtaining, at each battery management system node, a subset of electrical measurement values ​​of the battery stack, each subset of electrical measurement values ​​of the battery stack corresponding to a time specified by the measurement command.

[0042] In another embodiment of the fifth aspect, the method further includes: propagating the electrical measurement value of the first node of the plurality of battery management system nodes through at least one other node of the plurality of battery management system nodes.

[0043] In another embodiment of the fifth aspect, the method further includes removing power transfer switching noise and associated harmonics from electrical measurements of the fuel cell stack before determining that a series arcing fault has occurred in the fuel cell stack.

[0044] In another embodiment of the fifth aspect, the arc fault in the fuel cell stack is a parallel arc fault in the fuel cell stack, and the method further includes: (1) obtaining electrical measurements of the fuel cell stack, and (2) determining, in response to a mismatch between the currents flowing through the two battery management system nodes of the fuel cell stack, that a parallel arc fault has occurred in the fuel cell stack.

[0045] In another embodiment of the fifth aspect, the method further includes removing power transfer switching noise and associated harmonics from electrical measurements of the battery stack before determining that a parallel arcing fault has occurred in the battery pack.

[0046] In another embodiment of the fifth aspect, the method further includes: in response to determining that an arcing fault has occurred in the stack, performing controlled discharge of each battery within its respective battery management system node.

[0047] In a sixth aspect, a method for safe operation of an energy storage system, the energy storage system comprising at least a first stack of multiple battery management system nodes having output ports connected in series; the method comprising the steps of: (a) operating the battery management system nodes in various operating modes such that each battery management system node is capable of supplying power to a load electrically connected to the energy storage system, and (b) in response to a signal that the first stack is operating in a safe mode, operating a first subset of the battery management system nodes in various bypass modes while simultaneously operating a second subset of the battery management system nodes in various operating modes to reduce at least one of the voltage and current of the first stack.

[0048] In the implementation of the sixth aspect, enabling the first subset of battery management system nodes to operate in various bypass modes for each of the first subset includes the following steps:

[0049] (1) Isolate the battery of the battery management system node from the DC-DC converter of the battery management system node; and (2) Electrically short-circuit the output port of the battery management system node.

[0050] In another embodiment of the sixth aspect, for each of the second subset of battery management system nodes, enabling the second subset of battery management system nodes to continue operating in various operating modes includes: enabling the DC-DC converter of the battery management system node to convert the battery voltage into the voltage across the output port of the battery management system node.

[0051] In another embodiment of the sixth aspect, each battery management system node in the first battery stack is a member of a first subset of battery management system nodes or a second subset of battery management system nodes.

[0052] In another embodiment of the sixth aspect, the method further includes: changing the partitioning of the battery management system node of the first stack between a first subset and a second subset of the battery management system node.

[0053] In another embodiment of the sixth aspect, the method further includes: periodically changing the partitioning of the battery management system nodes of the first stack between a first subset and a second subset of the battery management system nodes.

[0054] In another embodiment of the sixth aspect, the method further includes: changing the partitioning of the battery management system nodes of the first battery stack between a first subset and a second subset in response to a signal that changes one or more of the voltage and current of the first battery stack.

[0055] In another embodiment of the sixth aspect, the method further includes: generating a signal for the first fuel cell to operate in a safe mode in response to detecting a fault in an energy storage system outside the first fuel cell stack.

[0056] In another embodiment of the sixth aspect, the fault in the energy storage system is an arc fault in the energy storage system outside the first stack.

[0057] In another embodiment of the sixth aspect, the fault in the energy storage system is a fault in the communication subsystem of the energy storage system.

[0058] In another embodiment of the sixth aspect, the method further includes: generating a signal for the first stack to operate in a safe mode in response to a user command.

[0059] In a seventh aspect, a method for safe operation of an energy storage system, the energy storage system comprising at least a first stack of multiple battery management system nodes having output ports connected in series; the method comprising the steps of: (1) operating the battery management system nodes in various operating modes such that each battery management system node is capable of supplying power to a load electrically connected to the energy storage system; and (2) operating the first stack in a bypass mode or a float charge mode in response to a fault in the communication subsystem of the energy storage system.

[0060] In a seventh aspect embodiment, operating the first stack in bypass mode includes: operating the node output short-circuit switches electrically connected to both ends of the output port of each battery management system node in their on state.

[0061] In another embodiment of the seventh aspect, operating the first battery stack in float charge mode includes: (1) at least partially electrically isolating each battery of each battery management system node by disconnecting the respective isolating switches electrically connected to the batteries; and (2) operating the respective node output short-circuit switches electrically connected to both ends of the output port of each battery management system node in their open state.

[0062] In another embodiment of the seventh aspect, the method further includes: in response to a failure of the communication subsystem of the energy storage system, performing controlled discharge of each battery of the battery management system node within each battery management system node.

[0063] In an eighth aspect, an energy storage system includes: (1) a first stack of a plurality of battery management system nodes, the plurality of battery management system nodes having respective output ports connected in series; and (2) a control subsystem configured to: (a) operate the battery management system nodes in various operating modes such that each battery management system node is capable of supplying power to a load electrically connected to the energy storage system, and (b) in response to a signal indicating that the first stack is to operate in a safe mode, operate a first subset of the battery management system nodes in various bypass modes while continuing to operate a second subset of the battery management system nodes in various operating modes to reduce at least one of the voltage and current of the first stack.

[0064] In an implementation of the eighth aspect, the control subsystem is further configured to change the partitioning of the battery management system node of the first stack between a first subset and a second subset of the battery management system node.

[0065] In a ninth aspect, a method for safe operation of an energy storage system, the energy storage system comprising at least a first stack of a plurality of battery management system nodes, the method comprising the steps of: (1) detecting a fault in the energy storage system; and (2) in response to detecting a fault in the energy storage system, reducing at least one of: (a) the voltage of the first stack to a non-zero value, and (b) the current of the first stack to a non-zero value, such that the first stack operates in a safe mode.

[0066] In the ninth aspect of the implementation, the fault in the energy storage system is an arc fault connected in series with the first fuel cell stack.

[0067] In another embodiment of the ninth aspect, the fault in the energy storage system is a parallel arc fault in the energy storage system outside the first fuel cell stack.

[0068] In another embodiment of the ninth aspect, the method further includes: in response to detecting a fault in the energy storage system, reducing at least one of the voltage and current of the second stack of a plurality of battery management system nodes.

[0069] In a tenth aspect, a method for safe operation of an energy storage system, the energy storage system comprising multiple battery management system nodes electrically connected together, the method comprising the following steps:

[0070] (1) Obtain a measurement of the first battery of the first battery management system node in the plurality of battery management system nodes; (2) Compare the measurement with the expected value; (3) Determine that the first battery is unsafe in response to the measurement differing from the expected value by at least a threshold amount; and (4) In response to the determination that the first battery is unsafe, electrically isolate the first battery from the individual batteries of the other battery management system nodes in the plurality of battery management system nodes.

[0071] In an embodiment of the tenth aspect, the measured values ​​of the first battery include at least one of the instantaneous voltage of the first battery, the instantaneous current of the first battery, and the instantaneous temperature of the first battery.

[0072] In another embodiment of the tenth aspect, the measured values ​​of the first battery include at least one of the rate of change of the voltage of the first battery, the rate of change of the current flowing through the first battery, and the rate of change of the temperature of the first battery.

[0073] In another embodiment of the tenth aspect, the method further includes: in response to determining that the first battery is unsafe, performing a controlled discharge of the first battery within a first battery management system node.

[0074] In another embodiment of the tenth aspect, performing controlled discharge of the first battery includes: electrically connecting a resistor to the first battery within a first battery management system node.

[0075] In another embodiment of the tenth aspect, performing controlled discharge of the first battery includes discharging the first battery via a current source electrically connected to the first battery management node.

[0076] In another embodiment of the tenth aspect, the method further includes, in response to determining that the first battery is unsafe, commanding a load electrically connected to the energy storage system to increase the power drawn from the energy storage system.

[0077] In another embodiment of the tenth aspect, the method further includes: in response to a parameter of the first battery exceeding a threshold, commanding a load electrically connected to the energy storage system to change the magnitude of the power drawn from the energy storage system.

[0078] In another embodiment of the tenth aspect, the parameters of the first battery include one of the state of charge (SOC) of the first battery and the voltage of the first battery.

[0079] In another embodiment of the tenth aspect, the load electrically connected to the energy storage system includes an inverter.

[0080] In another embodiment of the tenth aspect, the method further includes: prohibiting charging the first battery in response to determining that the first battery is unsafe.

[0081] In another embodiment of the tenth aspect, the method further includes: increasing the discharge rate of the first battery in response to determining that the first battery is unsafe.

[0082] In the eleventh aspect, a method for safe operation of an energy storage system, the energy storage system including a plurality of battery management system nodes electrically connected together, the method comprising the steps of: (1) receiving a signal indicating that a first battery of a first battery management system node among the plurality of battery management system nodes is unsafe; and (2) in response to receiving the signal indicating that the first battery is unsafe, performing controlled discharge of the first battery within the first battery management system node.

[0083] In an eleventh aspect of the implementation, performing controlled discharge of the first battery includes: electrically connecting a resistor to the first battery within a first battery management system node.

[0084] In another embodiment of the eleventh aspect, performing controlled discharge of the first battery includes discharging the first battery via a current source electrically connected to the first battery management system node.

[0085] In another embodiment of the eleventh aspect, the method further includes: in response to receiving a signal indicating that the first battery is unsafe, commanding a load electrically connected to the energy storage system to increase the power drawn from the energy storage system.

[0086] In another embodiment of the eleventh aspect, the method further includes: in response to a parameter of the first battery exceeding a threshold, commanding a load electrically connected to the energy storage system to change the magnitude of the power drawn from the energy storage system.

[0087] In another embodiment of the eleventh aspect, the parameters of the first battery include one of the state of charge (SOC) of the first battery and the voltage of the first battery.

[0088] In another embodiment of the eleventh aspect, the load electrically connected to the energy storage system includes an inverter.

[0089] In another embodiment of the eleventh aspect, the method further includes: prohibiting charging the first battery in response to receiving a signal indicating that the first battery is unsafe.

[0090] In another embodiment of the eleventh aspect, the method further includes: increasing the discharge rate of the first battery in response to receiving a signal indicating that the first battery is unsafe.

[0091] In a twelfth aspect, the energy storage system includes: (1) a plurality of battery management system nodes electrically connected together; and (2) a control subsystem configured to: (a) obtain a measurement of a first battery of a first battery management system node among the plurality of battery management system nodes, (b) compare the measurement with an expected value, (c) determine that the first battery is unsafe in response to the measurement differing from the expected value by at least a threshold amount, and (d) electrically isolate the first battery from the individual batteries of the other battery management system nodes among the plurality of battery management system nodes in response to the determination that the first battery is unsafe.

[0092] In a thirteenth aspect, an energy storage system includes: (1) a plurality of battery management system nodes electrically connected together; and (2) a control subsystem configured to: (a) receive a signal indicating that a first battery of a first battery management system node among the plurality of battery management system nodes is unsafe, and (b) in response to receiving the signal indicating that the first battery is unsafe, cause controlled discharge of the first battery to be performed within the first battery management system node.

[0093] In the fourteenth aspect, a method for safe operation of an energy storage system, the energy storage system including a first battery and a first DC-DC converter electrically connected to the first battery, the method comprising the steps of: (1) controlling the first DC-DC converter to discharge the first battery to a load electrically connected to the first DC-DC converter to supply power from the first battery to the load at least partially; and (2) controlling the first DC-DC converter to increase the discharge rate of the first battery to the load in response to a signal for performing controlled discharge of the first battery.

[0094] In an embodiment of the fourteenth aspect, the method further includes: in response to a signal that performs controlled discharge of the first battery, commanding the load to increase the power drawn from the energy storage system.

[0095] In another embodiment of the fourteenth aspect, the method further includes: in response to a parameter of the first battery exceeding a threshold, commanding the load to change the magnitude of the power drawn from the energy storage system.

[0096] In another embodiment of the fourteenth aspect, the parameters of the first battery include the state of charge (SOC) of the first battery or the voltage of the first battery.

[0097] In another embodiment of the fourteenth aspect, the load includes an inverter.

[0098] In another embodiment of the fourteenth aspect, the method further includes: prohibiting charging of the first battery in response to a signal that performs controlled discharge of the first battery.

[0099] In a fifteenth aspect, a battery management system node with reverse voltage fault mode protection includes: (1) a battery including a positive terminal and a negative terminal; (2) a DC-DC converter including an output port configured to be electrically connected in series with one or more additional battery management system nodes; (3) a first disconnecting switch electrically connecting the battery to the DC-DC converter and configured to selectively connect and disconnect the battery from the DC-DC converter; and (4) a second disconnecting switch configured to prevent current flow in the event of a short circuit with one or more of the additional battery management system nodes.

[0100] In a fifteenth aspect embodiment, the battery management system node further includes a controller configured to disconnect each of the first and second disconnect switches in response to a signal from the electrically isolated battery.

[0101] In another embodiment of the fifteenth aspect, a first disconnect switch is electrically connected between the positive terminal of the battery and the DC-DC converter, and a second disconnect switch is electrically connected between the negative terminal of the battery and the DC-DC converter.

[0102] In another embodiment of the fifteenth aspect, (1) the first disconnecting switch includes a first transistor, the first transistor including a first body diode, the anode of the first body diode being connected to a DC-DC converter, and the cathode of the first body diode being connected to the positive terminal of a battery; and (2) the second disconnecting switch includes a second transistor, the second transistor including a second body diode, the anode of the second body diode being connected to the negative terminal of a battery, and the cathode of the second body diode being connected to a DC-DC converter.

[0103] In another embodiment of the fifteenth aspect, the second isolating switch is electrically connected to the output port of the DC-DC converter.

[0104] In another embodiment of the fifteenth aspect, (1) the first disconnect switch includes a first transistor electrically connected between the positive terminal of the battery and the DC-DC converter, the first transistor including a first body diode, the positive terminal of the first body diode being electrically connected to the DC-DC converter, and the negative terminal of the first body diode being electrically connected to the battery; and (2) the second disconnect switch includes a second transistor, the second transistor including a second body diode, the negative terminal of the second body diode being connected to the positive terminal of the output port of the DC-DC converter.

[0105] In another embodiment of the fifteenth aspect, (1) the first disconnecting switch includes a first transistor electrically connected between the negative terminal of the battery and the DC-DC converter, the first transistor including a first body diode, the positive terminal of the first body diode being electrically connected to the negative terminal of the battery, and the negative terminal of the first body diode being electrically connected to the DC-DC converter; and (2) the second disconnecting switch includes a second transistor, the second transistor including a second body diode, the negative terminal of the second body diode being connected to the positive terminal of the output port of the DC-DC converter.

[0106] In another embodiment of the fifteenth aspect, the DC-DC converter includes one of a boost converter and a buck converter.

[0107] In a sixteenth aspect, a battery management system stack includes: (1) a first battery management system node including a first battery having a positive terminal and a negative terminal, a first DC-DC converter, and a first disconnecting switch electrically connecting one of the positive terminal and the negative terminal of the first battery to the first DC-DC converter; and (2) a second battery management system node including: a second battery having a positive terminal and a negative terminal; a second DC-DC converter; a second disconnecting switch electrically connecting one of the positive terminal and the negative terminal of the second battery to the second DC-DC converter; and a third disconnecting switch configured to prevent current flow in the event of a short circuit between the first battery management system node and the second battery management system node.

[0108] In a sixteenth aspect embodiment, a first disconnect switch is electrically connected between the positive terminal of the first battery and the first DC-DC converter, a second disconnect switch is electrically connected between the positive terminal of the second battery and the second DC-DC converter, and a third disconnect switch is electrically connected between the negative terminal of the second battery and the second DC-DC converter.

[0109] In another embodiment of the sixteenth aspect, the third disconnecting switch includes a transistor comprising a body diode, the positive terminal of which is connected to the negative terminal of the second battery, and the negative terminal of which is connected to the second DC-DC converter.

[0110] In another embodiment of the sixteenth aspect, the third isolating switch is electrically connected to the output port of the second DC-DC converter.

[0111] In another embodiment of the sixteenth aspect, the third isolation switch includes a transistor comprising a body diode whose negative terminal is connected to the positive terminal of the output port of the second DC-DC converter.

[0112] In another embodiment of the sixteenth aspect, each of the first DC-DC converter and the second DC-DC converter includes a respective boost converter.

[0113] In the seventeenth aspect, the battery pack includes: (1) a plurality of batteries connected in series, (2) a plurality of switches, and (3) a controller configured to control the plurality of switches such that each battery can be individually connected to or disconnected from a power source / sink.

[0114] In an embodiment of the seventeenth aspect, the plurality of switches include: (1) a respective isolating switch for each battery, each isolating switch being configured to selectively isolate its respective battery from other batteries in the battery pack; and (2) a respective bypass switch for each battery, each bypass switch being configured to selectively provide a path for current flowing through the battery pack to bypass its respective battery.

[0115] In another embodiment of the seventeenth aspect, the controller and a plurality of switches are configured to enable the battery pack to operate in a plurality of battery stack operating modes, including a normal charging mode, a normal discharging mode and a bypass mode.

[0116] In another embodiment of the seventeenth aspect, the plurality of stack operating modes further include one or more of a float charge mode and a safety mode.

[0117] In another embodiment of the seventeenth aspect, the controller is further configured to cause the battery pack to operate in one of a bypass mode, a float mode, and a safety mode in response to a fault in the energy storage system including the battery pack.

[0118] In another embodiment of the seventeenth aspect, the fault is selected from the group consisting of reactor-level series arc, system-level series arc, reactor-level parallel arc, system-level parallel arc, and subsystem faults of the energy storage system.

[0119] In another embodiment of the seventeenth aspect, (1) the controller and a plurality of switches are configured to enable the battery pack to operate in a plurality of stack operating modes, including a normal charging mode, a normal discharging mode and a float charging mode, and (2) the controller is further configured to enable the battery pack to operate in float charging mode in response to an arcing fault occurring in an energy storage system including the battery pack.

[0120] In another embodiment of the seventeenth aspect, the battery pack further includes a respective DC-DC converter electrically connected to each battery.

[0121] In another embodiment of the seventeenth aspect, each DC-DC converter is configured to transfer charge between its respective battery and another battery in the battery pack.

[0122] In another embodiment of the seventeenth aspect, each DC-DC converter is configured to transfer charge between its respective batteries and a bus electrically connected to the battery pack.

[0123] In another embodiment of the seventeenth aspect, each DC-DC converter is electrically connected to a bus.

[0124] In another embodiment of the seventeenth aspect, the bus electrically connects the battery pack to the electrical load.

[0125] In another embodiment of the seventeenth aspect, the bus is a power transfer bus configured to transfer charge between multiple batteries.

[0126] In another embodiment of the seventeenth aspect, the controller is configured to control the DC-DC converter to regulate the voltage on the bus.

[0127] In another embodiment of the seventeenth aspect, the controller is configured to control the DC-DC converter to regulate the voltage on the bus.

[0128] In the eighteenth aspect, the battery pack includes multiple battery management system (BMS) nodes and a controller. Each BMS node includes: (1) a battery, (2) an isolating switch configured to selectively isolate the battery of the BMS node from the batteries of other BMS nodes, and (3) a bypass switch configured to selectively provide a path for current flowing through the battery pack to bypass the battery of the BMS node. The controller is configured to control the isolating switch and bypass switch of each BMS node such that the battery of each BMS node can be individually connected to or disconnected from a power source / charger, and the batteries of the BMS nodes are electrically connected in series.

[0129] In an embodiment of the eighteenth aspect, the controller is further configured to control the isolation switch and bypass switch of each BMS node, such that each BMS node can operate independently of each other BMS node of the battery pack in multiple operating modes, including a normal charging mode, a normal discharging mode and a bypass mode.

[0130] In another embodiment of the eighteenth aspect, the multiple operating modes also include a float charge mode.

[0131] In another embodiment of the eighteenth aspect, the plurality of operating modes also includes a security mode.

[0132] In another embodiment of the eighteenth aspect, the controller is further configured to cause the first BMS node among the plurality of BMS nodes to operate in its bypass mode in response to the battery of the first BMS node being unsafe.

[0133] In another embodiment of the eighteenth aspect, the controller is further configured to discharge the battery of the first BMS node in response to the battery of the first BMS node being unsafe.

[0134] In another embodiment of the eighteenth aspect, the first BMS node further includes a discharge circuit configured to discharge the battery of the first BMS node, and the controller is further configured to discharge the battery of the first BMS node by activating the discharge circuit.

[0135] In another embodiment of the eighteenth aspect, each BMS node further includes a respective DC-DC converter electrically connected to a battery of the BMS node.

[0136] In another embodiment of the eighteenth aspect, each DC-DC converter is configured to transfer charge between the battery of its respective BMS node and the battery of at least one other BMS node of the battery pack.

[0137] In another embodiment of the eighteenth aspect, each DC-DC converter is configured to transfer charge between the battery and the bus at its respective BMS node.

[0138] In another embodiment of the eighteenth aspect, each DC-DC converter is electrically connected to a bus.

[0139] In another embodiment of the eighteenth aspect, the bus electrically connects the battery pack to the electrical load.

[0140] In another embodiment of the eighteenth aspect, the bus is a power transfer bus configured to transfer charge between individual batteries of a plurality of BMS nodes.

[0141] In another embodiment of the eighteenth aspect, the controller is further configured to control the DC-DC converter of each BMS node to regulate the voltage of the bus.

[0142] In the nineteenth aspect, a method for mitigating faults in an energy storage system, the energy storage system including a battery pack of multiple battery management system (BMS) nodes, the multiple battery management system (BMS) nodes including individual batteries connected in series, the method comprising: (1) transferring power between the batteries of the BMS nodes and an electrical load, and (2) in response to a fault occurring in the energy storage system, switching the battery pack from a normal charging / discharging mode to one of a bypass mode, a float charging mode, and a safety mode.

[0143] In the nineteenth aspect, the fault is selected from the group consisting of a series arc at the stack level, a series arc at the system level, a parallel arc at the stack level, a parallel arc at the system level, and a fault in a subsystem of the energy storage system.

[0144] In another embodiment of the nineteenth aspect, the method further includes discharging the battery of the first BMS node among the plurality of BMS nodes in response to the battery being unsafe.

[0145] In another embodiment of the nineteenth aspect, discharging the battery of the first BMS node includes discharging the battery of the first BMS node using a discharge circuit of the first BMS node.

[0146] In another embodiment of the nineteenth aspect, discharging the battery of the first BMS node includes: (1) operating the first BMS node in its bypass mode during battery pack charging, and (2) operating the first BMS node in its normal charging / discharging mode during battery pack discharging.

[0147] In another embodiment of the nineteenth aspect, discharging the battery of the first BMS node includes: transferring the charge of the battery of the first BMS node to one or more of the following: (1) individual batteries of one or more other BMS nodes among a plurality of BMS nodes; and (2) a bus electrically connected to the first BMS node.

[0148] In another embodiment of the nineteenth aspect, the method further includes: transferring the charge of a battery of a first BMS node among a plurality of BMS nodes to a battery of a second BMS node among a plurality of BMS nodes.

[0149] In another embodiment of the nineteenth aspect, the method further includes: transferring charge between the battery of a first BMS node in a plurality of BMS nodes and the bus electrically connected to the battery pack.

[0150] In another embodiment of the nineteenth aspect, the method further includes: adjusting the voltage of the bus to provide an auxiliary power rail.

[0151] In another embodiment of the nineteenth aspect, the method further includes transferring charge between a battery of a first BMS node in a plurality of BMS nodes and an electrical load electrically connected to a battery pack, the electrical load being capable of (1) supplying power to the battery pack and (2) receiving power from the battery pack. Attached Figure Description

[0152] Figure 1 This is an illustrative block diagram of an example Battery Management System (BMS) node.

[0153] Figure 2 This is an illustrative block diagram of an example energy storage system comprising multiple BMS stacks connected in parallel with an electrical load, each stack including multiple nodes connected in series.

[0154] Figure 3A It means to obtain by Figure 2 An illustrative flowchart of the first method for generating synchronous DC measurements from nodes in an example node stack.

[0155] Figure 3B It indicates that it is used to obtain by Figure 2 An illustrative flowchart of a second method for generating synchronous DC measurements from nodes in an example node stack.

[0156] Figure 4A It is shown Figure 2 An illustrative block diagram of a node in a first example implementation of a fuel cell stack, and an example timing diagram showing the propagation delay of signals transmitted between nodes.

[0157] Figure 4B It is shown Figure 2 An illustrative block diagram of the nodes of a second example embodiment of the fuel cell stack.

[0158] Figure 4C This is an illustrative block diagram showing the nodes of a third example embodiment of the fuel cell stack.

[0159] Figure 5A This is a schematic diagram of an example fuel cell stack including multiple nodes, illustrating the occurrence of a stack-level series arc fault within the stack.

[0160] Figure 5B It means detection Figure 5A The series arc fault within the fuel cell stack, and for Figure 5A An illustrative flowchart of the method for responding to series arc faults within a fuel cell stack.

[0161] Figure 6AThis is a schematic diagram of an example energy storage system in which no arcing fault occurs during normal operation.

[0162] Figure 6B During system-level series arc faults Figure 6A A schematic diagram of an example energy storage system.

[0163] Figure 6C It means detection Figure 6B System-level series arc fault voltage and its response Figure 6B An illustrative flowchart of the method for responding to system-level series arc fault voltage.

[0164] Figure 7A This is a schematic diagram of an example fuel cell stack including multiple nodes, illustrating the occurrence of parallel arc faults within the stack.

[0165] Figure 7B It means detection Figure 7A The electric arc fault current in the electric stack stage within the electric stack is parallel to and affects the electric stack stage. Figure 7A An illustrative flowchart illustrating the method for responding to parallel arc fault currents within the fuel cell stack.

[0166] Figure 8A This is a schematic diagram of an example energy storage system in which no arcing fault occurs during normal operation.

[0167] Figure 8B During system-level parallel arc faults Figure 8A A schematic diagram of an example energy storage system.

[0168] Figure 8C It means detection Figure 8B Parallel arc faults within the fuel cell stack and their impact on Figure 8B An illustrative flowchart illustrating the method for responding to parallel arc faults within a fuel cell stack.

[0169] Figure 9A This is a schematic diagram showing an example fuel cell stack in operating mode.

[0170] Figure 9B This is a schematic diagram showing an example fuel cell stack in bypass mode.

[0171] Figure 9C This is a schematic diagram showing an instance of a fuel cell stack in float charge mode.

[0172] Figure 9D This is a schematic diagram showing an example fuel cell stack in safe mode.

[0173] Figure 9E This is a fault response state diagram illustrating an example of how the fuel cell stack transitions between operating modes.

[0174] Figure 10 This is a schematic diagram illustrating a method for detecting an unsafe battery before it enters thermal runaway.

[0175] Figure 11 Is Figure 1 An illustrative circuit diagram of the first example bidirectional DC-DC converter circuit used in the example node.

[0176] Figure 12 Is Figure 1 An illustrative circuit diagram of the second example bidirectional DC-DC converter circuit used in the example node.

[0177] Figure 13A This is an illustrative circuit diagram of an example bidirectional DC-DC converter circuit used in the example node.

[0178] Figure 13B This indicates that the load includes Figure 13A Illustrative signal diagram of a bidirectional DC-DC converter for discharging and charging a battery.

[0179] Figure 13C It means Figure 13A An illustrative diagram showing the signal of a battery discharging through a load without being charged.

[0180] Figure 14A This is an illustrative circuit diagram showing a portion of two series-connected example nodes of a fuel cell stack lacking fault mode protection from reverse voltage in the disconnected state.

[0181] Figure 14B This illustrates the short-circuit fault caused by reverse voltage in the open state. Figure 14A An illustrative circuit diagram showing the flow of short-circuit current between the nodes of the fuel cell stack.

[0182] Figure 14C This is an illustrative circuit diagram showing a portion of an example node of a fuel cell stack connected in series, which includes a first example reverse voltage fault mode protection circuit in the off state during fault mode operation.

[0183] Figure 14D This illustrates the short-circuit fault caused by reverse voltage in the open state. Figure 14C An illustrative circuit diagram of the blocked short-circuit current between the nodes of the fuel cell stack.

[0184] Figure 14E This is an illustrative circuit diagram showing a portion of two series-connected example nodes of another example fuel cell stack, which includes a second example reverse voltage fault mode protection circuit in the off state during fault mode operation.

[0185] Figure 14FThis is an illustrative circuit diagram showing a portion of two series-connected example nodes of another example fuel cell stack, which includes a second example reverse voltage fault mode protection circuit in the off state during fault mode operation.

[0186] Figure 15 This is a schematic diagram illustrating an example of a battery data processing engine.

[0187] Figure 16 This is an illustrative block diagram of an example energy storage system that includes multiple BMS nodes but no DC-DC converters.

[0188] Figure 17 This is an illustrative block diagram of an example energy storage system including multiple BMS nodes, which are capable of transferring charge between cells in adjacent BMS nodes via capacitors between adjacent BMS nodes.

[0189] Figure 18 Showing the use of in Figure 17 The first step in a method for transferring charge between two batteries in an energy storage system.

[0190] Figure 19 Showing the use of in Figure 17 The second step in a method for transferring charge between two batteries in an energy storage system.

[0191] Figure 20 This is an illustrative block diagram of an example energy storage system including multiple BMS nodes, which are capable of transferring charge between cells within the BMS nodes via stack-level capacitors.

[0192] Figure 21 Showing the use of in Figure 20 The first step in a method for transferring charge between two batteries in an energy storage system.

[0193] Figure 22 Showing the use of in Figure 20 The second step in a method for transferring charge between two batteries in an energy storage system.

[0194] Figure 23 This is an example block diagram of an example energy storage system including multiple BMS nodes, which are capable of transferring charge between batteries of adjacent BMS nodes via inductors.

[0195] Figure 24 Showing the use of in Figure 23 The first step in a method for transferring charge between two batteries in an energy storage system.

[0196] Figure 25 Showing the use of in Figure 23The second step in a method for transferring charge between two batteries in an energy storage system.

[0197] Figure 26 This is an illustrative block diagram of an example energy storage system including multiple BMS nodes, which are capable of transferring charge between cells within the BMS nodes via stack-level inductors.

[0198] Figure 27 Showing the use of in Figure 26 The first step in a method for transferring charge between two batteries in an energy storage system.

[0199] Figure 28 Showing the use of in Figure 26 The second step in a method for transferring charge between two batteries in an energy storage system.

[0200] Figure 29 This is an illustrative block diagram of an example energy storage system comprising multiple BMS nodes, which are capable of transferring charge between cells within the BMS nodes via a stack-level resonant circuit including inductors and capacitors.

[0201] Figure 30 Showing the use of in Figure 29 The first step in a method for transferring charge between two batteries in an energy storage system.

[0202] Figure 31 Showing the use of in Figure 29 The second step in a method for transferring charge between two batteries in an energy storage system.

[0203] Figure 32 This is an illustrative block diagram of an example energy storage system including multiple BMS nodes, which are capable of transferring charge between batteries in adjacent BMS nodes via transformers and a system bus.

[0204] Figure 33 It is shown Figure 32 A diagram illustrating an example of charge transfer in an implementation of an energy storage system, which includes four BMS nodes.

[0205] Figure 34 yes Figure 32 An illustrative block diagram of an alternative implementation of an energy storage system including a dedicated power transfer bus.

[0206] Figure 35 yes Figure 34 An illustrative block diagram of an alternative implementation of an energy storage system, wherein a power transfer bus is configured to provide an auxiliary power rail. Detailed Implementation

[0207] While previous battery energy management systems and battery management system nodes were generally effective, their use had drawbacks. For example, conventional battery management system nodes could not identify and eliminate arcing faults. Furthermore, while battery isolators could isolate weak or failed batteries from the rest of the energy storage system, previous isolators typically did not protect good batteries from the effects of failed batteries. Thus, a good battery connected within a failed battery could transfer short-circuit voltage and current to adjacent batteries, potentially causing a fire. Moreover, typically only the failed battery was bypassed or disconnected. However, when the battery energy management system fails but the batteries are good, the ability to bypass the good batteries is necessary. For example, during installation and maintenance, having a non-zero but safe voltage to power the battery pack is useful for troubleshooting and testing whether the system is functioning correctly before full voltage and power are applied. It is also necessary to be able to maintain the battery voltage at a safe level for humans and low enough to easily extinguish most arcs. Although batteries are typically bypassed when they are determined to be potentially unsafe, simply bypassing an unsafe battery does not prevent it from catching fire and the fire from spreading to other healthy batteries. Therefore, it is necessary to identify and discharge unsafe batteries, even if they are not yet failed.

[0208] This document discloses a safe battery energy management system, a safe battery management system node, and related methods that at least partially overcome one or more of the aforementioned drawbacks of conventional systems, nodes, and methods. For example, some embodiments are configured to perform a tiered arc fault detection method capable of identifying arcs anywhere in the system. Additionally, some embodiments can operate in multiple modes to promote safety and ease of system maintenance and troubleshooting. Furthermore, some embodiments are configured to safely discharge the battery, such as in response to a fault or user command. Moreover, some embodiments are configured to prevent short-circuit current from flowing in response to reverse voltage.

[0209] Battery Management System Node Example

[0210] Figure 1 This is an illustrative block diagram of an example Battery Management System (BMS) node 100. The example BMS node 100 includes control circuitry 102 and a battery 104. In this document, the term "battery" includes a single electrochemical cell as well as a device comprising multiple electrochemical cells. Therefore, battery 104 can be a single electrochemical cell. Alternatively, battery 104 can be a multi-cell assembly comprising multiple electrochemical cells electrically connected together in series and / or parallel. Battery 104 can be a standalone device, or battery 104 can be co-packaged with another device or as part of another device.

[0211] Example node 100 includes a positive power bus (Bus+) terminal 251, a positive battery terminal (Bat+) 252, and a negative battery / power bus terminal (Bus-, Cell-) (“negative battery terminal”) 253. Node 100 is coupled to a communication bus 262. More specifically, node 100 includes a communication bus input terminal 254 and a communication bus output terminal 255. In example node 100, the communication bus 262 includes a serial data bus.

[0212] The control circuit 102 includes a bidirectional DC-DC converter 106, a sensing and measurement system 108, a temperature sensor 110, a processing and communication system 112, and a drive signal generation system 114. The converter 106 receives the battery voltage at terminals 252 and 253 as an input voltage and provides the node output voltage at terminals 251 and 253 as an output voltage. Therefore, the converter 106 converts (e.g., increases or decreases) the battery voltage at terminals 252 and 253 to the output node voltage at terminals 251 and 253, and vice versa. The sensing system 108 monitors battery temperature, battery current, and battery voltage characteristics over time and provides this information to the processing and communication system 112. The sensing system 108 also monitors the node output voltage, output current, and DC-DC converter temperature and / or the temperature of the battery 104. The node output voltage is the output voltage of DC-DC converter 106, which is provided across the positive power bus (Bus+) terminal 251 and the negative battery 253. It is the voltage output of DC-DC converter 106. Node current flows through the battery connected to DC-DC converter 106. The node output voltage and / or node output current can be used to identify arc faults, such as those described below. Figures 5A to 8C The temperature of the DC-DC converter can be used as a substitute for the temperature of the battery 104 to ensure safe discharge. Alternatively, the BMS node 100 can directly measure the temperature of the battery 104, and this temperature can be used to ensure safe discharge.

[0213] Example node 100 performs periodic voltage, current, and temperature (“VIT”) measurements. More specifically, as explained more fully below, battery voltage, battery current, battery temperature, and node output voltage measurements are used to determine the state of charge (SOC) estimate of battery 104 and / or dynamically control the charging and discharging of battery 104. For example, the example node performs voltage, current, and temperature (“VIT”) measurements at least once every 5 to 10 milliseconds.

[0214] In one aspect, the processing and communication system 112 processes information from the sensing system 108 based on stored control information specifying how to control the DC-DC converter 106 according to VIT measurements, and then outputs the information to the drive system 114 for appropriately controlling the converter 106 to convert the battery voltage to the node output voltage while achieving enhanced performance of the battery 104. In another aspect, the processing and communication system 112 controls the opening and closing of the node battery isolation switch 256 to selectively isolate the battery 104 from the converter 106. In yet another aspect, the processing and control system 112 controls the energy dissipation circuit 258, which provides a mechanism for safely discharging the battery 104 within the BMS node 100 without providing the node output voltage. Although the energy dissipation circuit 258 is described as a single switch, it can also take other forms, such as those described below. Figure 11 and Figure 12 The discussion is based on the premise that the energy consumption circuit 258 can perform controlled discharge of the battery 104 within the BMS node 100.

[0215] Battery 104 provides voltage across positive battery terminal 252 and negative battery terminal 253. Converter 106 provides node output voltage across positive power bus terminal 251 and negative power terminal 253. Positive power bus terminal 251 and negative power terminal 253 together serve as output port 260 where the node output voltage is provided. Some embodiments of BMS node 100 also include a node output short-circuit switch 257 electrically connected across output port 260, i.e., across positive power bus terminal 251 and negative power terminal 253. Alternatively, BMS node 100 may include a soft short-circuit switch 259 and a resistor 261 electrically connected in series across output port 260. As discussed below, controller 102 closes soft short-circuit switch 259, for example, to balance node output voltages among multiple instances of BMS node 100 during certain off-states. Resistor 261 need not be a discrete resistor, but may be the parasitic resistance of soft short-circuit switch 259.

[0216] Converter 106 converts the battery voltage supplied across positive battery terminal 252 and negative battery terminal 253 into a node output voltage supplied across positive power bus terminal 251 and negative battery terminal 253. Example sensing and measurement system 108 includes a sensing, driving, and signal conditioning module 220 electrically connected to the outputs CS1 and CS2 of a current sensor 160 measuring battery current, a temperature sensor 110 measuring the temperature of the converter and / or battery 104, positive power bus terminal 251, positive battery terminal 252, and negative power terminal 253. Sensing, driving, and signal conditioning module 220 prepares and conditions the current, temperature, and voltage input signals to be measured over time at current measurement module 221, temperature measurement module 222, and voltage measurement module 223. Sensing and measurement system 108 includes a current signal line 278, a temperature signal line 280, and a voltage signal line 282, which are coupled to transmit the measured values ​​to processing and communication system 112.

[0217] Processing and communication system 112 is coupled to receive signals from sensing system 108. Processing system 112 also includes output connections to drive system 114. Drive system 114 includes input signal connections 272 from processing system 112 and one or more output signal connections 276 to DC-DC converter 106.

[0218] The processing and communication system 112 includes module 217, which includes analog-to-digital converter (ADC) circuitry 217-1, processor circuitry 217-2, digital storage device 217-3, and optional digital-to-analog converter (DAC) 217-4. ADC 217-1 converts analog measurements of voltage, current, and temperature received from sensing system 108 into corresponding digital values. In one aspect, processor circuitry 217-2 correlates the current, temperature, and voltage data with instructions contained in digital storage device 217-3 and processes the cell charging / discharging algorithm to determine the control signals to be sent to drive system 114. In some embodiments, DAC 217-4 converts the control signals generated by processor circuitry 217-2 from digital to analog form before the control signals are transmitted to drive system 114. Example processing and communication module 112 of node 100 communicates with stack controller 210 (hereinafter referred to as...) via communication bus 262. Figure 2(As described) Sending data and receiving data and instructions from the fuel cell controller 210. Optional example nodes (not shown) can use wireless communication to send and receive data and instructions from the fuel cell controller. For example, in some alternative embodiments, communication bus input terminal 254 and communication bus output terminal 255 are replaced by one or more wireless transceivers to enable node 100 to communicate wirelessly with the fuel cell controller 210 and / or other instances of node 100. In these alternative embodiments, communication bus 262 may be omitted.

[0219] The drive system 114 processes the control signals received from the processing and communication system 112 and generates drive control signals to control the DC-DC converter 106 to control battery charging and discharging operations.

[0220] The processing and communication system 112 includes a bus interface circuit 113 for sending and receiving information via a communication bus 262. In some embodiments, the bus interface circuit 113 receives input information at a communication bus input terminal 254 and provides output information at a communication bus output terminal 255 to sequentially transmit information among multiple instances of BMS nodes 100. An example communication bus 262 includes differential daisy-chain circuitry. Optional example nodes (not shown) include wireless communication interfaces for communicating with a stack controller (not shown) and / or other nodes. In some alternative embodiments, data does not need to be sent or received sequentially; instead, another data transmission technique can be used. For example, in some alternative embodiments, data is transmitted in parallel between BMS node 100 and two or more other points (such as other BMS nodes).

[0221] Example processing and communication circuit 112 sends commands to drive system 114 to control DC-DC converter 106 based on voltage, current, and temperature measurements obtained by sensing system 108 and algorithms stored as instructions and lookup tables in digital storage device 217-3. Example node 100 is accessed via the following reference. Figure 2The described stack controller 210 receives instructions and lookup tables from the main controller 212. Algorithms are encoded to adjust the voltage and / or current characteristics of battery 104 (via converter 106) to achieve desired performance. For example, if the processing system 112 determines, based on VIT measurements, that the current discharge rate of a particular battery 104 (evaluated by measurements from sensing system 108) suggests the cell's lifespan will be two months shorter than the required lifespan, the algorithm, based on the calculated lifespan deficit and the current current and voltage operating characteristics of battery 104, looks up the appropriate adjustments to converter 106 to be applied to that battery 104 in the lookup table. An example battery management system node 100 is disclosed in U.S. Patent No. 8,686,693, which is expressly incorporated herein by reference in its entirety.

[0222] Energy storage system example

[0223] Figure 2 It includes multiple BMS battery packs S1 to S K An illustrative block diagram of an example energy storage system 200, wherein the node output voltage is connected in parallel with the electrical load 204. Each stack S1 to S2... K The batteries inside are stacked in series to generate sufficient voltage. (As mentioned above...) Figure 1 The battery 104 discussed may be (a) a single electrochemical cell or (b) a multi-cell assembly comprising multiple electrochemical cells connected in series and / or parallel. To avoid unnecessary complexity and to promote clarity of explanation, details of the stack S1 are explained, and stacks S2 to S3 are shown in block form. K Details have been omitted. However, it will be understood that the details and operating principles explained with reference to fuel cell stack S1 also apply to other fuel cell stacks S2 to S... K The fuel cell stack S1 includes multiple nodes N1 to N... N Their node output voltages V1 to V N The sum of these components is connected in parallel with the electrical load 204. The load 204 can be, for example, a photovoltaic (PV) system and an inverter connected to the grid. Alternatively, for example, the load 204 can be, for example, the electric motor and battery charger of an electric vehicle (EV). Therefore, the load 204 can both receive power from the energy storage system 200 and supply power to the energy storage system 200 to charge the battery 104. Example BMS stacks S1 to S2 K Each node in is equivalent to Figure 1 Node 100, although nodes N1 to N N Details are not shown in the accompanying drawings to simplify the illustration.

[0224] The fuel cell stack S1 includes multiple nodes N1 to N NEach node converts the cell voltage of its individual 104 batteries into the output voltage of that node, as described above. Figure 1 The discussion focuses on multiple nodes N1 to N of S1. N Make their node output voltages V1 to V N Series connection. For example, node N. N Negative power bus terminal 253 N Connect to node N N-1 Positive power bus terminal 251 N-1 Furthermore, for example, the negative power bus terminal 2532 of node N2 is connected to the positive power bus terminal 2511 of node N1. Nodes N1 to N of the stack S1... N The output voltage V1 to V of the series connection node N It is electrically connected in parallel with electrical load 204. Example fuel cell stack S1 includes a stack controller 210, which is connected to monitor nodes N1 to N... N The main controller 212 is operably coupled to the stack controller 210. In some alternative embodiments, two or more stacks S1 to S2 are used. K Sharing a common stack controller 210 eliminates the need for each stack to have its own stack controller 210. Furthermore, although the main controller 212 is described as a discrete entity, some or all aspects of the main controller 212 may be incorporated into one or more stack controllers 210. Additionally, the main controller 212 may be implemented partially or entirely by one or more computing devices located remotely from the rest of the energy storage system 200, for example, in a distributed or cloud computing system. Moreover, in some embodiments, the main controller 212 is not dedicated to the energy storage system 200 but is configured to at least partially control multiple energy storage systems. Additionally, in some other alternative embodiments, the main controller 212 and each stack controller 210 are implemented by a single controller (not shown).

[0225] For example, for grid-connected energy storage devices, the stack voltage is typically from several hundred volts to over several thousand volts. For a battery voltage of about four (4) volts (per battery cell), there is typically a stack of one hundred (100) to three hundred (300) or more battery cells connected in series. For example, assuming a boost ratio of 1.2, the stack will typically include from fifty (50) to one hundred and fifty (150) or more nodes per stack. The number of stacks connected in parallel sets the total power and energy capacity of the example system 200, and is typically in the range of, for example, from one to many ten (10) or more, or one hundred (100) or more. For large-scale batteries used in known automobiles, a stack including one hundred (100) battery nodes would be a twenty-four (24) kWh system. Therefore, about fifty (50) stacks connected in parallel would provide a 1 MWh system for commercial applications. Utility-scale systems can typically be one hundred (100) MWh or larger. Of course, there will be practical limitations on how many stacks can be used in parallel, such as the number of stacks that can be physically (and safely) assembled in a standard transport container. A load current measurement circuit 206 is connected to measure the load current I through the load 204. L A load voltage measurement circuit 208 is connected to measure the voltage V across the load. L The main controller 212 is connected to receive I L Measure and receive V L Measurement.

[0226] During normal operation, the nodes N1, N2...N of the fuel cell stack S1... N-1 N N The DC-DC converters operate independently of their associated batteries 104 N1 104 N2 ……104 N-1 104 NN Charging and discharging are performed so that the voltage, current, and other parameters of a battery can be managed independently of the other batteries in the stack S1. Furthermore, each node includes a respective node cell isolation switch 256 to selectively connect the node's DC-DC converter 106 to the node's battery 104 and disconnect the node's DC-DC converter 106 from the node's battery 104 during safe mode operation, as described below.

[0227] Example fuel cell stack S1 includes a communication bus 262, which connects the nodes of the stack to send and receive information from the S1 stack controller 210. The communication bus 262 is configured according to nodes N1 to N... N The sequential communication bus 262 transmits information to and from nodes in a daisy-chain structure, where communication bus sections 2621 to 262 are provided between sequentially ordered nodes. In example stack S1, the sequential communication bus 262 has a daisy-chain structure, wherein communication bus sections 2621 to 262 are provided between sequentially ordered nodes.N Signals are sent sequentially from node to node, following the node order. In example stack S1, the node order proceeds sequentially from stack controller 210 to the first node in sequence N1, to the second node in sequence N2, and so on, until sequence N... N The last node in the sequence. An example sequential bus has a ring topology, where the last node N of the sequence... N The stack controller 210 is connected to the beginning of the sequence in the loop.

[0228] In the example system, nodes N1 to N of the stack S1 N The nodes are interconnected to form a communication controller area network, where control and data signals communicate between the nodes and the fuel cell stack controller 210. More specifically, in the example system, the communication bus 262 comprises two lines, namely low and high. However, the communication bus 262 may have other configurations without departing from the scope of the invention. For example, the communication bus 262 may be an optional type of wired communication bus. As another example, the communication bus 262 may be a wireless communication bus or a hybrid wired-wireless communication bus. Each node may prepare and broadcast information (e.g., voltage, current, and temperature data) via the bus 262 in response to commands received from the fuel cell stack controller 210 through the bus 262. The broadcast data can be received by all other nodes on the communication bus 262. Each node examines the information received through the communication bus 262 and decides whether to process it, ignore it, or pass it on to the next node in the network.

[0229] Example stack controller 210 includes stack processor circuitry 214 operatively coupled to storage device 216, storage device 216 including first battery management code (C) accessible and executable by processor circuitry 214. BM1 ), First Arc Detection Code (C AD1 ) and First Security Management Code (C SM1 ).

[0230] In the example stack S1, the first battery management (C) in the storage device 216 BM1 The code contains instructions that, when executed, configure the fuel cell processor circuitry 214 to manage the charging and discharging of the cells at the nodes of the fuel cell stack S1 based on, for example, measured voltage, current, and temperature at the nodes of the fuel cell stack. For example, Example 1 C BM1 The code configures the stack processor circuit 214 to collect data from each node N1 to N2 of the stack S1. N The system measures battery, current, and temperature, and sends the measurements to the main controller 212 for processing. Example 1 C BM1The code also configures the stack processor circuit 214 of the S1 stack controller 210 to receive instructions from the main controller 212 via the timing and control bus 219 to help determine adjustments to the operation of the batteries 104 at each node, optimize the overall performance of the nodes of the stack S1, and send the received instructions to nodes N1 to N2. N This allows for adjustments. The replacement example stack controller 210 wirelessly exchanges information with the main controller 212.

[0231] In the example stack S1, the first arc detection (C) in the storage device 216 AD1 The code includes instructions that, when executed, configure the fuel cell processor circuit 214 for detecting and responding to arc fault conditions based on measurements of voltage and current within the nodes of the fuel cell stack S1. For example, Example 1 C AD1 The code configures the stack processor circuit 214 to transmit measurement request commands, so that the BMS nodes N1 to N of the stack S1 can be connected. N Synchronous voltage and current measurements are provided, synchronous measurements are collected from nodes, and synchronous measurements are sent to the master controller 212 for processing via timing and control bus 219. In some embodiments, voltage measurements are synchronized independently of current measurements, so that voltage measurements do not need to be synchronized with current measurements. Example 1 C AD1 The code also configures the fuel cell processor circuit 214 to detect the occurrence of a series arc fault in fuel cell S1, and to detect the occurrence of a parallel arc fault in example fuel cell S1, and in response to such occurrence, to open the isolating switch 256 of the node of fuel cell S1 and / or perform another action. Example C AD1 The code also configures the fuel cell processor circuit 214 to receive instructions from the main controller 212 via the timing and control bus 219 indicating the occurrence of a system-level series arc fault or an indication of the occurrence of a system-level parallel arc fault, and, for example, in response to such occurrence, causes the N1 to N... N The disconnecting switch 256 is opened and / or another action is performed. In some embodiments, the fuel cell processor circuit 214 is also configured to cause the soft short-circuit switch 259 to close in response to a detected series or parallel arcing fault to equalize the voltage across the node. Optionally, the fuel cell controller 210 wirelessly exchanges system-level series arcing fault information or system-level parallel arcing fault information with the main controller 212.

[0232] In example stack S1, the first safety management (C SM1 The code includes instructions that, when executed, configure the stack processor circuit 214 to switch nodes N1 to N2 of the stack S1 between operating modes, bypass modes, float charge modes, and safety function modes. N For example, in example C... SM1The code configures the fuel cell processor circuit 214 to receive instructions from the main controller 212 via the timing and control bus 219, indicating commands to transfer nodes between fuel cell operating modes. Example: First C SM1 The code also configures the stack controller to send instructions to the nodes of stack S1, thereby selectively opening and closing the isolating switch 256 based on instructions received from the main controller 212, thus switching the stack between operating modes. The alternative example stack controller 210 wirelessly exchanges operating mode, safety mode, float charge mode, and low-power function mode information with the main controller 212.

[0233] The main controller 212 includes a controller processor circuit 218 operatively coupled to the storage device 220, the storage device 220 including access to the controller processor circuit 218 and a second battery management (C) function executable by the controller processor circuit 218. BM2 ) code, second arc detection (C AD2 ) code and second security management (C SM2 Code. Example 2 C BM2 The code includes instructions that, when executed, configure the controller processor circuitry 218 to manage the charging and discharging of the batteries at the nodes of the BMS stack S1, for example, based on measured voltage, current, and temperature of the nodes of the stack S1. For example, Example 2 C BM2 The code configures the controller processor circuit 218 to collect voltage, current, and temperature measurements from the battery stack S1, and uses information from a storage table to select instructions to adjust the performance of each cell 104 in the battery stack based on the collected measurements representing the unique and evolving performance characteristics of each cell, thereby enhancing overall system performance. Example 2 C BM2 The code also configures the controller processor circuit 218 to send instructions to the stack processor circuit 214 via the timing and control bus 219 to adjust the stack S1 to S2. K This optimizes the operation of each battery 104, thereby improving the overall performance of the system 200. The example stack controller 210 is replaced with stacks S1 to S2. K The main controller 212 wirelessly exchanges information.

[0234] Example C AD2 The code includes instructions that, when executed, configure the controller processor circuitry 218 for use with nodes N1 to N based on the stack S1. N Synchronous measurement of voltage and current within the stack, as well as the measured stack current and voltage, are used to detect and respond to arc fault conditions. For example, Example 2 C AD2 The code configures the controller processor circuit 218 to send instructions to cause the multiple stacks S1 to S... KThe fuel cell controller and the fuel cell voltage V collected by the main controller 212 L and stack current I L The node voltage and node current measurements are collected synchronously. However, in some implementations, voltage measurements are synchronized independently of current measurements, so that voltage measurements do not necessarily need to be synchronized with current measurements. Example 2 C AD2 The code also configures the controller processor circuit 218 to detect the occurrence of system-level series arc faults and system-level parallel arc faults in the fuel cell stack, and sends information to the fuel cell stack S1 to S2 via timing and control bus 219. K One or more of these, in response to such occurrence, cause the node isolating switch 256 to open and / or another action. Replacement example: main controller 212 with fuel cells S1 to S... K The fuel cell stack controllers exchange information wirelessly.

[0235] Example C SM2 The code includes instructions that, when executed, configure the controller processor circuitry 218 to switch between multiple fuel cell stacks S1 to S2 between operating mode, bypass mode, float charge mode, and safety function mode. K One or more nodes in the array. For example, example C in the second instance. SM2 The code configures the controller processor circuit 218 to send instructions to multiple BMS stacks via timing and control bus 219 to indicate operating modes. Example 2 C SM2 The code also provides examples of fuel cell stacks S1 to S2. K One or more transmission commands are sent to indicate, for example, which isolating switches can be selectively opened and closed during low-power operation. An optional example is the main controller 212 with fuel cells S1 to S2. K The fuel cell stack controllers exchange information wirelessly.

[0236] Arc fault

[0237] Example electrical storage systems may experience arcing, where gas (typically air) between two nearby conductors at different potentials is ionized due to a large voltage and / or small gap between them, resulting in current flow between the conductors. The potential of such arcing is complex because typical electrical storage systems include many electrical connectors and long cables, presenting numerous potential points of failure. Some electrical storage systems are susceptible to physical damage, such as from environmental conditions, maintenance personnel working near the system, or animals chewing on system components. Arcs can be classified as series arcs or parallel arcs. For example, series arcs occur at the open ends of a series circuit, such as those caused by connector failure. Parallel arcs occur, for example, between parallel voltage or current paths in an electrical system, or between voltage or current carrying conductors and ground, such as due to insulation failure.

[0238] Arc detection devices for energy management systems have been proposed, which detect arcs by identifying high-frequency components, or "noise," in the energy storage system current generated by the arc. The noise amplitude is very small and must be amplified or increased using a current transformer for detection. Furthermore, the noise must be distinguished from other high-frequency components typically present in the photovoltaic system current, such as ripple current from switching power converters and its harmonics. Therefore, conventional arc detection devices typically use Fast Fourier Transform (FFT) or similar techniques to decompose the photovoltaic system current into its constituent AC components to differentiate the arc noise from other system noise. This signal decomposition usually requires significant computational resources to perform satisfactorily.

[0239] Government and / or industry standards often specify a certain time from the establishment of an arc until the arc detection system detects or interrupts the arc. For example, for Type 1 Series arc detectors, UL 1699B specifies that this time should not exceed two (2) seconds, and for higher power arcs, it should not exceed t = 750 joules / IV. When multiple battery packs S1 to S2 are included, providing DC voltage and DC current... K In the absence of an electric arc in the energy storage system 200, the AC signal components are typically very small, except for peaks associated with the switching of power electronics (such as DC-DC converter 106 or inverter) within the system. During an electric arc, a more complex AC spectrum may occur with greater amplitudes than in the absence of an arc. However, even during an electric arc, the amplitude of peaks caused by the switching of power electronics may be significantly greater than the electrical noise caused by the arc. Furthermore, even for a particular device, these peaks are not guaranteed to be at a specific frequency, as they can operate at different frequencies depending on the conditions present. In energy storage systems comprising a large number of nodes per stack (such as fifty (50) to one hundred and fifty (150) or more nodes per stack), where VIT measurements are performed at least every 5 to 10 milliseconds per node, there may be a greater challenge, for example, in synchronizing DC voltage and current measurements for arc detection. Furthermore, there is a possibility that DC measurements of voltage and current may misidentify (alias) large AC peaks that occur due to the switching of power electronics. Therefore, arc detection schemes that use synchronous DC voltage and synchronous DC current measurements to detect arcs must detect arcs quickly and reliably without causing annoying tripping due to other noise sources in the system (e.g., power electronic switches).

[0240] Measurement synchronization

[0241] Figure 3A It indicates that it is used to obtain by Figure 2An illustrative flowchart of a first method 350 for generating synchronous DC measurements at nodes of an example node stack S1. Method 350 is used, for example, to obtain synchronous electrical and / or temperature measurements for arc fault detection and / or other aspects of managing the energy storage system 200, such as those used by processor circuits 217-2, processor circuit 214, and / or processor circuit 218 to control the charging and discharging of battery 104. In step 352, the stack controller 210 sends data to nodes N1 to N... N A measurement request command is sent. In step 354, at a specified time, each node responds to the command by simultaneously measuring at least one DC parameter, such as voltage, current, and / or temperature. In step 356, the DC measurement value of the command is transmitted through nodes N1 to N... N The data is propagated to the stack controller 210. Next, control flows back to step 352 in loop 359 to repeat steps 352 to 356, thereby generating a continuous sequence of measurement samples. In an alternative embodiment, step 356 is modified such that the DC measurements are transmitted from node N1 to N... N Transmitted to the stack controller 210 in another manner, such as by wired or wireless transmission directly from each node to the stack controller 210.

[0242] Figure 3B It indicates that it is used to obtain by Figure 2 An illustrative flowchart of a second method 360 for generating synchronous DC measurements at nodes of an example node stack S1. For example, method 360 is used to obtain synchronous electrical and / or temperature measurements for arc fault detection and / or for managing other aspects of the energy storage system 200, such as those used by processor circuits 217-2, processor circuit 214, and / or processor circuit 218 to control the charging and discharging of battery 104. N Periodically measure one or more DC parameters, such as voltage, current, and temperature, and save one or more DC parameters to its storage device 217-3. As explained above, for example, the example node performs voltage, current, and temperature (“VIT”) measurements at least once every 5 to 10 milliseconds. Each node N1 to N N Optionally, each measurement can be timestamped.

[0243] In step 364, the stack controller 210 sends signals to nodes N1 to N... N A measurement request command is sent. In step 366, in response to the measurement request command, each node selects one or more saved measurements, such as voltage and / or current corresponding to a time or time window specified by the measurement request command. For example, each node N1 to N NOne or more saved measurement values ​​can be selected corresponding to the time or time window specified by the measurement command, or for each node N1 to N. N Multiple measurement values ​​available in memory can be selected when a node receives a measurement command. In some implementations, each node N1 to N N It has a common time base so that nodes can select the saved time measurement value corresponding to the time or time window specified by the measurement command.

[0244] In some other implementations, each node N1 to N N The selection of stored measurements is based at least in part on the node's position in the string and the time required for a measurement request command to propagate from one node to another. For example, suppose the propagation time between adjacent nodes in the string is Δt. A third node in the string can select a stored measurement corresponding to a time 3*Δt before the third node receives the measurement request command, to compensate for the propagation delay of the measurement request command in the string.

[0245] In some other embodiments, the stack controller 210 can send signals to each node N1 to N2. N A custom timing reference is provided, enabling nodes to select one or more measurements corresponding to a specified time or time window. The stack controller 210, for example, is based on the stack controller 210 and each node N1 to N... N The propagation delay measured between the two phases is used to determine a custom timing reference. The stack controller 210 measures the propagation delay, for example, during startup or periodically.

[0246] In step 368, the selected DC measurements, selectively including timestamps, are propagated through the nodes of the fuel cell stack to the fuel cell stack controller 210. Next, control flows back to step 362 on loop 369 to repeat steps 362 through 368, thereby generating a continuous sequence of measurement samples. In an alternative implementation, step 368 is modified such that the DC measurements are transmitted from node N1 to N in a different manner. N Transmission to the stack controller 210, such as via wired or wireless transmission directly from each node to the stack controller 210.

[0247] It will be understood that the first method 350 involves performing synchronous measurements, and the second method 360 involves selecting previously saved measurements. During the first method 350, the measurements performed in step 354 are performed synchronously at multiple nodes at a time determined based on a measurement request command signal. During the second method 360, the selected measurements include measurements previously saved at multiple nodes, and measurements selected during a time window determined based on the measurement command request signal. Both the first method 350 and the second method 360 obtain measurement values ​​for each of the multiple nodes. As explained more fully below, the measurement values ​​may optionally be processed to eliminate potential erroneous identification due to switching of circuit components and to generate measurement values ​​indicating whether an arcing fault may have occurred. In the case of obtaining measurement values ​​via the second method 360, the processing may involve time alignment from measurements selected within time windows at different nodes.

[0248] Figure 4A It is shown as Figure 2 The first example of the implementation of the fuel cell stack S is the nodes N1 to N of the fuel cell stack 420. N An illustrative block diagram, and an example timing diagram 422 showing the propagation delay of signals transmitted between nodes. As explained below, nodes N1 to N... N Synchronous voltage measurements at these locations are used to detect and prevent series arcing faults, and / or for managing one or more other aspects of the energy storage system 200. As explained below, nodes N1 to N... N The synchronous current measurement is also used to detect and prevent parallel arcing faults, and / or for managing one or more other aspects of the energy storage system 200. In some embodiments, voltage measurements are synchronized independently of current measurements, so that voltage measurements do not necessarily need to be synchronized with current measurements.

[0249] Figure 4A First example stack implementation 420 according to Figure 3A The first method, 350, can be operated, and according to... Figure 3B The second method can be performed using 360. (Refer to...) Figure 3A and Figure 4A When operating according to the first method 350, in step 352, the stack controller 210 of the first example stack implementation 420 sends a measurement request command via the communication bus 262 to command nodes N1 to N N Each node performs a synchronous measurement. More specifically, in step 352, the stack controller 210 sends a measurement request command to node N1 via communication bus section 2620. Node N1 then sequentially sends measurement request commands to node N2 via communication bus section 2621, and so on, until node N... N-1 via communication bus section 262 N-1 To node N N Send measurement command.

[0250] In step 354, at a predetermined time, each node simultaneously measures one or more DC parameters in response to a measurement request command (e.g., voltage and / or current). The predetermined time is determined to be an appropriate time to allow the measurement request command to propagate sequentially to each node in the stack 420 before the nodes simultaneously measure the parameters commanded. More specifically, in step 354, at nodes N1 to N... N After each node in the network has received a measurement request command, nodes N1 to N... N Synchronously use their ADC 217-1 to at nodes N1 to N N Each of the commands in the table is executed digitally for DC measurement. (See reference...) Figure 2 and Figure 4A In the example implementation, the main controller 212 sends signals to the fuel cell stacks S1 to S2 via the timing and control bus 219. K Each of the fuel cell stack controllers provides the master clock signal, fuel cell stacks S1 to S2. K Each stack controller in the system then provides a master clock signal to the node for synchronizing measurements at the node of each stack and at both ends of the different stacks in the synchronization system 200. The master clock can also be used to synchronize the timestamps of the measurements.

[0251] In the example stack S1, nodes N1 to N N Measurement is delayed in response to receiving a measurement request command until the last node N in the sorted sequence. N A measurement request command is received. In example stack S1, the nodes know the total number of nodes in the stack and their sequential positions within the stack. In the first example stack implementation 420, the nodes are configured to synchronize digital capture voltage measurements and synchronize digital capture current measurements, for example, based on the propagation delay in the transmission of the measurement request command signal between nodes. In the first example stack implementation 420, the propagation delay is Δt between the time a node receives a voltage measurement request command or a current measurement request command and the time the next node in the sequence receives a voltage or current measurement request command. Thus, for example, assuming N1 receives the command at time t0, then N2 receives the command at t0+Δt, N3 receives the command at t0+2Δt, and so on, until node N... N A command is received at t0+NΔt. In the first example fuel cell embodiment 420, in order to achieve synchronous measurement in response to a measurement command, each node in the sequence delays the execution of the command measurement until the last node in the sequence receives the measurement command. More specifically, in the first example fuel cell embodiment 420, N1 delays the measurement by at least a time interval NΔt; N2 delays the measurement by at least a time interval (N-1)Δt, and so on, and the measurement of node N has no delay associated with Δt.

[0252] refer to Figure 3A and Figure 4A In step 356, the DC measurement of the timestamp command is propagated to the stack controller 210 through the nodes of the stack. More specifically, in the first example stack implementation 420, after the synchronous digital capture of the command's voltage and current measurements, for example, each node sends the timestamped voltage measurement and the timestamped current measurement to the stack controller 210 via communication bus 262. For example, N1 sends its measurement to N2 via bus section 2621, N2 then sends N1's measurement to N3 via bus section 2622, and so on, until N1's measurement reaches N... N N N Instead, it is transmitted via bus section 262. N The measurement of N1 is sent to the fuel cell stack controller 210. Furthermore, for example, N... N-1 via bus section 262 N-1 Send the measurement of its command to N N N N Instead, it is transmitted via bus section 262. N N N-1 The measurements are sent to the stack controller. For example, node N N via bus section 262 N The measurements are sent directly to the stack controller 210. As described below, the example stack controller 210 at each stack processes the voltage and current measurements received from the individual nodes within its stack to identify the occurrence of arc fault conditions within its stack.

[0253] Reference Figure 3B and Figure 4A When operating according to the second method 360, in step 362, for example, each node performs routine periodic voltage, current, and temperature measurements to determine the state of charge estimate of battery 104 and / or dynamically control the charging and discharging of battery 104. Each node may also optionally timestamp at least a portion of the periodic measurements and store at least a portion of the periodic measurements in its local storage device 217-3. In some embodiments, the main controller 212 communicates with the battery stacks S1 to S2 via timing and control bus 219. K Each of the fuel cell stack controllers 210 provides a master clock signal, fuel cell stacks S1 to S2. K Each stack controller 210 in the stack then provides a master clock signal to the node for timestamping stored measurements and synchronizing the collection of stored measurements at both ends of the node for individual stacks and at both ends of different stacks. In some embodiments, in step 364, the stack controller 210 of the first example stack implementation 420 sends a measurement request command via communication bus 262 to command nodes N1 to N N Each execution node N1 to N NThe previously performed measurements are collected synchronously, as described above with reference to step 352. The measurement request command is propagated node-to-node with the propagation delay described above. In step 366, each node in the first example embodiment of the fuel cell stack 420 selects one or more stored measurements to be performed within a specified time window or at a specified time. For example, assuming each node performs a DC voltage measurement and a DC current measurement at intervals of 5 to 10 milliseconds, a time window with a duration of 5 to 10 milliseconds may include one voltage and one current measurement, and a time window with a duration of 50 to 100 milliseconds may include, for example, ten voltage and ten current measurements. At step 368, the timestamped measurements collected in response to the command are propagated through the nodes of the fuel cell stack to the fuel cell stack controller 210, as described above with reference to step 356.

[0254] Figure 4B It is shown Figure 2 The nodes N1 to N of the second example embodiment of the fuel cell stack 430 N An illustrative block diagram. A second example embodiment of the fuel cell stack 430 includes a synchronization command bus 402, which is coupled to provide measurement request commands to multiple nodes synchronously without propagation delay, although the communication bus 262 connecting the signals between the nodes experiences propagation delay, as referenced above. Figure 4A Those described. For example, the synchronization bus 402 also serves as an alarm line for sending alarm signals, thereby forcing the energy storage system into bypass mode, float charge mode, or safety mode, or a sudden change from charging to discharging or back again. The advantage of this optional implementation is that it is easy to synchronize and the results are faster. Measurements are still sent along the daisy-chain bus (N*Δt), but it is not necessary for measurement request commands to also propagate through the bus (another N*Δt). To avoid unnecessary complexity and to promote illustrative clarity of explanation, components of the second example embodiment of the fuel cell stack 430 corresponding to those of the first example embodiment of the fuel cell stack 420 will no longer be described.

[0255] Figure 4B The second example stack implementation 430 can be based on Figure 3A The first method is 350 operations, and can be based on Figure 3B The second method is 360 operation. (Refer to...) Figure 3A and Figure 4B When operating according to the first method 350, in step 352, the stack controller 210 of the second example stack implementation 430 sends a measurement request command via the synchronization command bus 402 to simultaneously send commands to nodes N1 to N2. N Provide a measurement request command. In step 354, at the specified time, nodes N1 to N... NIn response to a measurement request command, one or more parameters, such as voltage and / or current, are measured simultaneously. For example, the specified time when a measurement request command is received via bus 402 can be instantaneous. The main controller 212 provides a master clock signal via timing and control bus 219, which is used to synchronize the timestamps of the measurements. In step 356, as described above, the timestamp measurement executed in response to the command is propagated through the nodes of the fuel cell stack to the fuel cell stack controller 210. In some embodiments, within a fuel cell stack S1 to S2... K The measurements performed in each of the other stacks S1 to S2 are compared with those performed in each other stack. K Measurement synchronization performed in the process, such as based on the master clock signal from the master controller 212.

[0256] Reference Figure 3B and Figure 4B When operating according to the second method 360, in step 362, nodes N1 to N N Routine periodic voltage, current, and temperature measurements are performed to determine the state of charge (SOC) estimate of battery 104 and / or to dynamically control the charging and discharging of battery 104 as described above. The main controller 212 provides a master clock signal via timing and control bus 219 for timestamps of the measurements. In step 364, the stack controller 210 of the second example stack implementation 430 sends a measurement request command via synchronization command bus 402 to simultaneously send commands to nodes N1 to N... N A measurement request command is provided. In step 366, at a specified time, each node responds to the measurement request command by selecting one or more saved measurements, such as voltage and / or current. More specifically, in step 366, in a second example embodiment of the fuel cell stack 430, each node selects one or more saved measurements to be performed within a specified time window or at a specified time. In some embodiments, measurements performed within the specified time window may not be performed simultaneously, such as due to propagation delays or processing delays. In this case, the saved measurements may optionally be time-aligned, such as by using interpolation techniques. In step 368, the selected measurements with timestamps are propagated through the nodes of the fuel cell stack to the fuel cell stack controller.

[0257] Figure 4C These are nodes N1 to N of a third example embodiment of the fuel cell stack 440. N An illustrative block diagram. Nodes N1 to N in the third example fuel cell stack implementation 440. N The fuel cell stack controller 210 and the main controller 212 include a wireless transceiver 470 for wireless communication between them. In this embodiment, wireless communication replaces the synchronization command bus 402 and the communication bus 262. In the example system 400, the nodes, fuel cell stack controller, and main controller are configured to operate as a wireless mesh communication area network. Figure 4C The third example of the fuel cell stack implementation 440 is generally based on Figure 3A The first method 350 is operable, and is usually based on Figure 3B The second method 360 is operable, although the transceiver 470 at the node can avoid the need for sequential signal propagation between nodes. Instead, for example, in some embodiments, the node can communicate directly and wirelessly with the stack controller 210. Based on the above references Figures 4A to 4B With this explanation, those skilled in the art will understand the applicability of the first method 350 and the second method 360, and therefore, to avoid unnecessary complexity and promote clarity of explanation, no reference is made. Figure 4C The application details of the first process 350 and the second process 360 are explained.

[0258] Detection of series arc faults at fuel cell stack level

[0259] Figure 5A It includes multiple nodes N1 to N N A schematic diagram of an example BMS stack 500 illustrates the occurrence of a stack-level series arcing fault within the stack. A series arcing is the result of an anticipated continuity failure of a conductor or connector in a circuit. As used herein, a stack-level series arcing fault refers to an arc within an individual stack, not an arc in the connection between stacks. Stack 500 is connected in parallel with an electrical load 504. Each node N1 to N... N The corresponding node output voltages V1 to V are generated in series connection. N The voltages of the series-connected nodes V1 to V2 are... N It is connected by a conductor network 502 in parallel with the load 504. During normal operation in which no series arcing fault occurs within the stack 500, the sum of the node voltages within the stack 500 matches the set voltage of the stack and is consistent with, for example, a measured voltage of the stack.

[0260] V STACK =V1+V2+V3+…+V N

[0261] However, a series arcing fault occurring at a node within the fuel cell stack 500 adds a series voltage element to the fuel cell stack voltage V. STACK The occurrence of a series arc fault will cause the V at both ends of the 500 stack to... STACK Nodes N1 to N of individuals with a stack size greater than or less than 500 N The voltage across the terminals V1…….V N The sum of the set values, and the nodes N1 to N of the individual stack 500 that are greater than or less than the set values. N The voltage across the terminals V1…….V NThe sum of the measurements. For example, if a series arc fault voltage V occurs between node N2 and node N3 within the stack 500. ARC ,but,

[0262] V STACK =V1+V2+V3+...+V N +V ARC

[0263] Therefore, in this illustrative example, the series arc voltage V within the fuel cell stack ARC Make the voltage V across the 500 stack STACK The sum of the node output voltages of the mismatched fuel cell stack. Figure 5B This is an example flowchart of method 550 for detection. Figure 5A Series arc fault within the fuel cell stack and for Figure 5A It reacts to a series arcing fault within the fuel cell stack. Code instruction C AD1 and C AD2 A stack controller (not shown) is used to configure the stack for execution. Figure 5B The method involves obtaining voltage measurements at each node of the fuel cell stack at step 552. Example step 552 may include... Figure 3A The first method 350 obtains a node voltage measurement, which is synchronized with a measurement command signal at both ends of the node. An optional example step 552 may include... Figure 3B The second method 360 obtains node voltage measurements that include measurements falling within or performed during a common time window. In some implementations, the node voltage measurements obtained in step 552 are filtered, for example, by using one or more low-pass filters, to remove noise injected by the power conversion circuitry and associated harmonics that may otherwise interfere with arc fault detection.

[0264] In step 555, the stack voltage V is measured synchronously with the synchronous node voltage measurement. stack Decision step 556 determines whether the sum of the measured node voltages of the fuel cell stack is consistent with (e.g., matched) the measured stack voltage. In step 558, in response to determining the measured node voltages V1+V2+V3+......+V N The sum of these values ​​does not match the stack voltage, and differs from the stack voltage by at least a specified threshold amount, declaring a series arc fault in the stack level, i.e., a voltage V occurs. ARCIn example system 500, the specified difference is large enough to indicate the occurrence of a series arc, contrary to normal variations in the stack voltage level that may occur, for example, due to voltage drops across the nodes from the connectors and wires connected in series. Additionally, the specified difference may be large enough to account for normal variations due to measurement tolerances. In example system 500, when the stack voltage is in the range of 500V to 1000V, a difference of 1%, 2%, or even up to 5%, or a difference of several volts up to about 20V, between the node voltage and the sum of the stack voltages maintained for at least a specified minimum time interval (such as at least one second) generally indicates a stack-level series arc fault. In some other embodiments, decision step 556 detects a mismatch between the measured sum of node voltages and the measured stack voltage only if the mismatch persists for a predetermined amount of time or a predetermined number of measurement cycles.

[0265] In other embodiments, at least some of the voltages considered in step 556 are filtered to achieve a desired arc fault detection distribution. For example, in a particular embodiment, in step 556, (a) an error value equal to the difference between the sum of the measured node voltages and the measured stack voltage is determined, (b) the error value is filtered by a low-pass filter, and (c) a stack-level series arc fault is determined in response to the filtered error value satisfying or exceeding a predetermined threshold amount. In step 556, the low-pass filter weights the arc fault detection distribution by increasing the desired amplitude or duration of the arc fault voltage used for detection.

[0266] In step 560, the control node safely extinguishes the arc. This may include isolating any energy storage cells that can feed power to the arc as needed, with or without emergency cell discharge, while providing the required node output characteristics (float charge, short circuit, low power, or power-limited state). These fault responses are discussed in more detail below. Optionally or additionally, stack 500 may be controlled to discharge its cells to load 204 or to another stack, such as in a manner that limits the discharge current amplitude to a safe value, to help extinguish the arc. Method 550 is repeated periodically. During active fault management in example system 500, for example, method 550 may be repeated multiple times per second, every few seconds, or every few minutes. Optionally, method 550 may be repeated less frequently, approximately once a day upon power-up, to avoid overburdening computing resources.

[0267] System-level series arc fault detection

[0268] Figure 6A This is a schematic diagram of an example energy storage system 600 in which no arc fault occurs during normal operation. Figure 6B During system-level series arc faults Figure 6AA schematic diagram of an example energy storage system 600 is provided. As used herein, a system-level series arc fault refers to a series arc fault occurring outside the node stack, either in the electrical connection between node stacks or in the electrical connection between the node stack and a load. Each stack contains one or more nodes, and the stack voltage is the sum of the measured voltages of the nodes of the stack. Alternatively, as referenced above... Figures 5A to 5B As described, the stack voltage is the voltage measured across the stack. The stack voltage can be locally summed at the stack controller (not shown) of an individual stack and reported to the main controller, or alternatively, the node voltages at an individual stack can be reported to the main controller (not shown), which sums the node voltages received from the individual stacks to determine the individual stack voltage. The stack voltage and load voltage are compared at the main controller (not shown). System 600 includes multiple BMS stacks Stack1, Stack2, Stack3, which are connected in parallel with an electrical load 604 via a conductor network 602. To avoid unnecessary complexity and to promote clarity of explanation, details of the stacks are omitted. However, it will be understood that, for example, the example system 600 may have similar characteristics to... Figure 2 The system topology of 200. In the system topology of 200. Figure 6A During normal operation, when no series arc fault occurs, the fuel cell stack has a matched stack voltage across its terminals, which is the voltage V across the matched load. L :

[0269] V LOAD =V STACK1 =V STACK2 =…=V STACKN

[0270] However, an arcing fault in series with one of the fuel cells will result in a voltage across the fuel cells that is different (higher or lower) from the voltage across the other fuel cells and different from the voltage V across the load. L Different voltage readings. For example, such as Figure 6B As shown, if a series arc fault V ARC If it occurs in series with Stack2, then,

[0271] V LOAD =V STACK1 =[V STACK2 +V ARC ]...=V STACKN

[0272] Therefore, in this illustrative example, a system-level arc fault (with a voltage V across the stack) is described. ARC Make the voltage V measured across Stack2... STACK2 Lower than other fuel cell stack voltages and load voltage V LOADFor example, an arc could be the conductor itself, a connection from the conductor to the battery pack, or a connection from the conductor to the bus. If one of the battery stack voltages is mismatched with the others, the master controller can determine that a system-level series arcing fault has occurred at the mismatched stack. In this example, the master controller is configured to determine at the master controller that the voltage across Stack2 is mismatched with the voltages of the other battery stacks and with the load voltage V. LOAD A mismatch identifies the location of the arc as being within an electrical connection between Stack2 cells. In an example system, for example, the main controller (not shown) can send a command to the stack controller (not shown) of the mismatched stack to control the nodes of the stack, thereby extinguishing the arc while other stacks remain operational. Mitigation techniques may include placing the stack in an off state or a low-power safe state, while optionally discharging the cells to improve safety. In one example, battery 104 may be isolated from nodes with node output float charging to extinguish the current path of the series arc. Furthermore, optionally, for example, the nodes of the mismatched stack can be switched to a safe mode, in which technicians can more safely (this will be explained below) troubleshoot to locate the source of a system-level series arc fault.

[0273] Figure 6C It means detection Figure 6B System-level series arc fault voltage and its response Figure 6B An illustrative flowchart of the method for responding to system-level series arc fault voltages (650). Code instruction C AD1 and C AD2 For configuration Figures 6A to 6B The system 600's stack controller (not shown) and main controller (not shown) work together to execute... Figure 6C The method involves obtaining the node voltage measurement for each node of each stack (Stack1, Stack2, Stack3) at step 652. Example step 652 may include a first method 350. Optionally, example step 652 may include a second method 360. At step 654, the sum of the measured voltages for each stack is determined to determine the stack voltage V. STACK1 V STACK2 V STACK3 In an alternative embodiment, steps 652 and 654 are replaced by the step of obtaining a separate measured stack voltage for each stack. In step 655, the load voltage V is measured synchronously with the stack voltage measurement. L .

[0274] In some implementations, the voltage measurements obtained in steps 654 and 655 are filtered, for example, by using one or more low-pass filters to remove noise injected by the power conversion circuitry and associated harmonics that may otherwise interfere with arc fault detection. In some implementations, the one or more low-pass filters used to filter the measured load voltage values ​​have substantially the same bandwidth as the one or more low-pass filters used to filter the stack voltage measurements and / or node voltage measurements. In this document, the first low-pass filter and the second low-pass filter are considered to have substantially the same bandwidth if the bandwidth of the first low-pass filter differs from the bandwidth of the second low-pass filter by no more than 10 percent.

[0275] Decision step 656 determines whether the stack voltages are matched to each other and to the load voltage. In some implementations, at least some of the voltages considered in decision step 656 are filtered to achieve a desired arc fault detection distribution, such as in a manner similar to that described above. Figure 5B The method discussed in step 556. Step 658 responds to determining that all stack voltages are matched to each other and to the load voltage, and that there is no system-level series arcing. Decision step 660 determines whether a single stack voltage is mismatched with other stack voltages. Step 662, in response to a system-level series arcing fault, controls the node to safely extinguish the arc. This may include isolating any energy storage cells that can feed power to the arc as needed, with or without emergency cell discharge, while providing the required node output characteristics (float charge, short circuit, low power, or power-limited state). Step 664, in response to determining that more than one stack voltage is mismatched with other stack voltages or that the load voltage is mismatched with the stack voltage, isolates each node in each stack from all other stacks and the load voltage. Method 650 is repeated periodically. During active fault management in example system 600, for example, method 650 is repeated multiple times per second, every few seconds, or every few minutes. Alternatively, method 650 can be repeated less frequently, approximately once a day at power-on, to avoid overburdening computer resources.

[0276] In some embodiments, the stack controller 210 and / or the main controller 212 execute methods 550 and 650 sequentially or simultaneously to achieve hierarchical series arc fault detection. More specifically, the stack controller 210 and / or the main controller 212 executes method 550 to achieve first-level series arc fault detection, i.e., stack-level series arc fault detection, to detect series arc faults within the stack. Additionally, the stack controller 210 and / or the main controller 212 executes method 650 to achieve second-level series arc fault detection, i.e., system-level series arc fault detection, to detect series arc faults outside the stack. Therefore, these embodiments advantageously enable the detection of series arc faults at any location within the energy storage system 200, both inside and outside the stack. Furthermore, methods 550 and 650 optionally share the measured stack voltage values ​​and / or measured node voltage values, which helps minimize measurement acquisition and processing requirements. Moreover, the concept of hierarchical series arc fault detection can be extended to include additional levels. For example, in some alternative implementations where the fuel cell stack includes multiple modules, series arc fault detection is performed at the module level as well as the aforementioned fuel cell stack level and system level to achieve hierarchical series arc fault detection.

[0277] Parallel arc fault detection at fuel cell stack level

[0278] Figure 7A It includes multiple nodes N1 to N N A schematic diagram of an example BMS stack 700 is provided, illustrating the occurrence of parallel arcing faults within the stack. To avoid unnecessary complexity and to promote clarity of explanation, details of the stack 700 are omitted. However, it will be understood that, for example, the example stack 700 may have similar characteristics to... Figure 2 The topology of fuel cell stack S1. As used herein, a stack-level parallel arc fault refers to an arc from one point within the stack to another point within the stack or to ground. Fuel cell stack 700 is connected in parallel with electrical load 704. Each node N1 to N... N Generate the corresponding node output currents I1 to I N The nodes connected in series are linked by a conductor network 702 in parallel with the load 704. During normal operation, when no parallel arc fault occurs within the stack 700, the stacks I1 to I... N The sum of the currents within the system is matched.

[0279] I STACK =I1=I2=I3=…=I N

[0280] However, the parallel arc fault current within the fuel cell stack 700 leads to the parallel arc fault current I. ARC The parallel arc fault current I ARCIt can be added to or subtracted from some currents within the fuel cell stack. For ground faults and parallel arc faults within the fuel cell stack, the arc fault current I... ARC This causes the node currents to no longer be equal. For example, if a sustained parallel arcing fault I occurs between nodes N2 and N3... ARC Then, I1=I2≠I3=…=I N ,as well as

[0281] I STACK =I N =I3=I2+I ARC =I1+I ARC

[0282] It will be understood that the direction of the arc fault current can change, and therefore, it can be added to or removed from the node; the illustrative example above assumes the addition of an arc fault. Therefore, in this illustrative example, the stack-level parallel current fault I... ARC The occurrence of this event causes the current through at least one node to be mismatched with the current through the other nodes.

[0283] The location of a node in a parallel arc fault within the fuel cell stack is determined by an arc fault location process, which includes comparing the currents of adjacent node sequences within the stack. The stack controller is configured to execute the arc fault location process, which determines whether the currents in adjacent node pairs match. This process identifies nodes where the current within a node does not match the currents in the nodes adjacent to that node. The location of a node in a sequence where the current matches the current in its adjacent nodes to a node where the current does not match at least one of its adjacent nodes is determined to be the location of a parallel arc fault within the fuel cell stack. Therefore, the location of a parallel arc fault within the fuel cell stack is determined by finding where the current changes within the stack. For example, refer to... Figure 7A I1 = I2 and I3 = I4 = ... = I N However, I2 = I3 + I ARC In this example, there is an additional current flowing from the connection between N2 and N3 to another point in the stack, and it is determined that an arc occurs at either node N2 or node N3.

[0284] Therefore, the location of the parallel current can be determined at the point in the stack where the series current interruption occurs, i.e., at the point where the current amplitude changes, such as at the junction between nodes N2 and N3 in this example. The arc fault location process can be used, for example, by maintenance technicians to more quickly locate and repair the fault. In an example system, the stack controller can send commands to the nodes of the stack to isolate their battery units, thereby de-energizing the nodes and extinguishing the arc. Furthermore, optionally, a subset of the nodes of stack 700 can be switched to a safe mode, in which technicians can more safely perform fault finding to locate the source of the stack-level parallel arc fault. Figure 7B This is an example flowchart representing method 750, which is used for detection. Figure 7A The stack stage of the fuel cell has parallel arc fault current and is related to... Figure 7A The stack stage within the fuel cell stack reacts to the parallel arc fault current. Code instruction C AD1 and C AD2 Used for configuration and Figure 7A The fuel cell stack is associated with a fuel cell controller (not shown) and a main controller (not shown) to perform... Figure 7B The method involves obtaining a node current measurement for each node of the fuel cell stack at step 752. For example, the current at each DC-DC 106 converter is measured. Example step 752 may include... Figure 3A The first method 350 obtains the node current synchronized with the measurement command signal at both ends of the node. An optional example step 752 may include... Figure 3B The second method 360 obtains node currents that fall within or during the synchronization time window.

[0285] In some implementations, the node current is estimated rather than measured directly. For example, the measured current of battery 104 can be scaled by the transfer ratio of the respective DC-DC converters 106 to obtain the estimated node current. The efficiency of the DC-DC converters 106 can be taken into account when determining the estimated node current to improve estimation accuracy. In some implementations, the node current measurement obtained in step 752 is filtered, such as by using one or more low-pass filters, to remove noise injected by the power conversion circuitry and associated harmonics that may otherwise interfere with arc fault detection.

[0286] Decision step 754 determines whether all measured node currents match. In example stack 700, a mismatch is determined in response to a difference of one percent (1%) or greater, two percent (2%) or greater, or even five percent (5%) or greater persisting for up to one second or longer. Current measurements are typically no more accurate than about one percent (1%), although measurement accuracy can be improved using precision devices or new technologies. Additionally, dynamic node operation can also cause differences in node currents. Otherwise, these currents should match very closely. Therefore, in other words, it will be understood that we simply avoid "measurement error" by setting an error of one percent (1%), two percent (2%), or five percent (5%). In step 756, in response to determining that not all measured node currents match, a stack-level parallel arc fault is declared. In some other embodiments, decision step 754 detects a mismatch in node currents only if the mismatch persists for a predetermined amount of time or a predetermined number of measurement cycles.

[0287] In some implementations, at least some of the currents considered in step 754 are filtered to achieve a desired arc fault detection distribution. For example, in a particular implementation, in step 754, (a) an error value equal to the difference between node currents is determined, (b) the error value is filtered by a low-pass filter, and (c) a parallel arc fault at the stack level is detected in response to the filtered error value meeting or exceeding a predetermined threshold amount. In step 754, the low-pass filter weights the arc fault detection distribution by increasing the desired amplitude or duration of the arc fault current used for detection.

[0288] In step 758, in response to a declaration of a parallel arc fault at the stack level, a disconnecting switch (not shown) is controlled at the node to safely extinguish the arc. This may include isolating any cells that can feed power to the arc as needed, with or without emergency cell discharge, while providing the desired node output characteristics (float charge, short circuit, low power, or power-limited state). In step 760, in response to determining that the measured node currents of the stack are all matched, it is declared that there is no parallel arc fault at the stack level.

[0289] System-level parallel arc fault detection

[0290] Figure 8A This is a schematic diagram of an example energy storage system 800 in which no arcing fault occurs during normal operation. Figure 8B During system-level parallel arc faults Figure 8AA schematic diagram of an example energy storage system 800 is provided. A parallel arcing fault occurs due to an unexpected current path between conductors in the expected current path. As used herein, a system-level parallel arc refers to an arc from one point outside the stack to another point outside the stack (most commonly an electrical ground), sometimes referred to as a ground fault. System 800 includes multiple BMS stacks Stack1, Stack2, Stack3, which are connected in parallel by a conductor network 802 with electrical loads 804. To avoid unnecessary complexity and to promote illustrative clarity of explanation, details of the stacks are omitted. However, it will be understood that, for example, the example system 800 may have similar characteristics to... Figure 2 The topology of system 200. Figure 8A During normal operation, assuming no system-level parallel arc fault occurs, the sum of the currents through the individual fuel cells equals the current through the load:

[0291] I LOAD =I STACK1 +I STACK2 +…+I STACKN

[0292] It can be used within the stack controller (not shown) (such as using Figure 3A Method 350 or Figure 3B Method 360) is used to determine the individual stack currents. Alternatively, the stack current can be estimated from the average or median of the individual node currents. However, system-level parallel arcing faults increase the parallel current, which causes the sum of the individual stack currents to be different from the current through the load. For example, as... Figure 8B As shown, if a continuous parallel arc fault I occurs within Stack1... ARC1 ,but,

[0293] I LOAD =[I STACK1 +I ARC1 ]+I STACK2 +…+I STACKN

[0294] Therefore, in this illustrative example, the system-level parallel current fault I ARC The occurrence of this causes the load current I L The sum of mismatched currents passing through the fuel cell stack.

[0295] Figure 8C This is an illustrative flowchart illustrating a method 850 for detecting system-level parallel arc fault current and responding to system-level parallel arc fault current. Code instruction C AD1 and C AD2 For configuration Figures 8A to 8B The system's stack controller (not shown) and main controller (not shown) are used to execute... Figure 8C The method. In step 852, the current value I of each fuel cell stack is determined. STACK1 …...I STACKN For example, according to Figure 7B Step 752 determines the current of each fuel cell stack. In step 854, the load current I is measured synchronously with the fuel cell stack current measurement. L .

[0296] In some implementations, the current measurements obtained in steps 852 and 854 are filtered, for example, by using one or more low-pass filters, to remove noise injected by the power conversion circuitry and associated harmonics that may otherwise interfere with arc fault detection. In some implementations, the one or more low-pass filters used to filter the measured load current values ​​have substantially the same bandwidth as the one or more low-pass filters used to filter the stack current measurements and / or node current measurements.

[0297] Decision step 856 determines whether the sum of the measured stack currents equals the load current. The stack current is measured at each individual stack, and the stack current measurement is transmitted to the main controller 212 for summation and comparison with the load current. In some embodiments, at least some of the currents considered in decision step 856 are filtered to achieve a desired arc fault detection distribution, such as in a manner similar to the above. Figure 7B The method discussed in step 754.

[0298] Refer again Figure 8C In step 858, a system-level parallel arc fault is declared in response to determining that the sum of the stack currents is not equal to the load current. In example system 800, a mismatch is determined in response to a difference of one percent (1%) or greater, two percent (2%) or greater, or even five percent (5%) or greater persisting for up to one second or longer. In step 860, a disconnecting switch (not shown) of the control node is used to safely extinguish the arc. This may include isolating any energy storage cells that can feed power to the arc while providing the required node output characteristics (float charge, short circuit, low power, or power-limited state) and, as needed, with or without emergency cell discharge. In step 862, a determination is made that there is no system-level parallel arc fault in response to determining that the sum of the stack currents equals the load current. Method 850 is repeated periodically. During effective fault management in example system 800, for example, method 850 is repeated multiple times per second, every few seconds, or every few minutes. Alternatively, method 850 can be repeated less frequently, approximately once a day, to avoid overburdening computer resources.

[0299] In some embodiments, the stack controller 210 and / or the main controller 212 execute both methods 750 and 850 sequentially or simultaneously to achieve hierarchical parallel arc fault detection. More specifically, the stack controller 210 and / or the main controller 212 executes method 750 to achieve first-level parallel arc fault detection, i.e., stack-level parallel arc fault detection, to detect parallel arc faults within the stack. Additionally, the stack controller 210 and / or the main controller 212 executes method 850 to achieve second-level parallel arc fault detection, i.e., system-level series-parallel fault detection, to detect parallel arc faults outside the stack. Therefore, these embodiments advantageously enable the detection of parallel arc faults at any location in the system (i.e., inside and outside the stack). Furthermore, methods 750 and 850 optionally share the measured stack current value, which helps minimize measurement acquisition and processing requirements. Moreover, the concept of hierarchical series arc fault detection can be similar to the above regarding… Figure 6C The approach discussed is extended to include additional levels.

[0300] Operating modes, bypass mode, float charge mode, and security mode.

[0301] Figure 9A , Figure 9B , Figure 9C and Figure 9D This indicates the operating mode ( Figure 9A Bypass mode Figure 9B ), float charging mode ( Figure 9C ) and safe mode ( Figure 9D A schematic diagram of the example BMS stack 900 in (). Figure 9A , Figure 9B , Figure 9C and Figure 9D Each node includes a battery 104, a DC-DC converter 106, an isolating switch 256, and a node output short-circuit switch 257. Each node may (and typically will) include additional components, such as those mentioned above. Figure 1 The components discussed, but for clarity, in Figure 9A , Figure 9B , Figure 9C and Figure 9D These additional components are not shown in the document. Figure 9A In the operating mode shown, the isolating switch 256 of the example stack 900 is closed to connect each battery 104 to nodes N1 to N2. N Each DC-DC converter 106 within the device converts the voltage of each battery 104 to the voltage at each output port 2601 to 260. N Output voltages V1...V at each node N The nodes N1 to N of the fuel cell stack NThe series output voltages together provide the stack output voltage V. STACK The output voltage of the fuel cell stack is V STACK Equal to the sum of the node output voltages of the fuel cell stack:

[0302] V STACK =V1+V2+...+V N

[0303] exist Figure 9B In the bypass mode shown, the isolation switch 256 of the node of the example stack is disconnected to disconnect each cell 1041 to 104 N With nodes N1 to N N The individual DC-DC converters 106 within the stack are electrically decoupled and isolated, and the node output short-circuit switch 257 is closed, causing each node to provide a 0V node output voltage. As a result, the nodes of the stack collectively provide the stack output voltage V. STACK =0V.

[0304] In float charge mode, such as Figure 9C As shown, the isolation switch 256 of the node of the example stack is disconnected to disconnect each cell 1041 to 104 N With nodes N1 to N N Each DC-DC converter 106 within is electrically decoupled and isolated, and switch 257 is open (or absent), causing nodes N1 to N... N The output node voltage is not connected to ground but floats. For example, float charging mode is a preferred response to system-level series arcing faults because it eliminates the current path of the arc, but a voltage drop still exists across the fuel cell stack. In float charging mode, the fuel cell stack is high impedance and the voltage across the stack is determined by its load. Optionally, some implementations also include a soft short-circuit switch 259 and a resistor 261 (in... Figure 9C (Not shown in the image), they are connected in series across the output port 260 of each node, as described above. Figure 1 As discussed. In these embodiments, the soft short-circuit switch 259 closes during float charge mode to provide a controlled impedance across the stack 900. The controlled impedance is determined, for example, by the sum of the resistance values ​​of resistors 261.

[0305] exist Figure 9DIn the illustrated safety mode, isolating switches 256 of the first subset of nodes in the example stack are closed to connect battery 104 to the respective DC-DC converters 106, which convert the battery voltage to the node output voltage. In the second subset of nodes in the example stack, isolating switches 256 are open to isolate battery 104 from the respective DC-DC converters 106 and the associated node output port 260. Additionally, switches 257 of the second subset of nodes are closed, bypassing each node in the second subset. The number of nodes within the first and second subsets is selected such that the nodes in the first subset collectively provide output voltage, current, and power limited to a safe level, while bypassing the nodes in the second subset. In the example energy storage system, a typical safety level is, for example, 30V, 8A, and 240W. Figure 9D In the example switch configuration shown, nodes N1 and N N In the first subset, disconnect switch 256 is closed to separate their associated batteries 1041 and 104 N Each node is connected to its respective DC-DC converter 106, and nodes N2 and N3 are in the second subset. Isolating switch 256 disconnects their associated batteries 1042 and 1043 from their respective DC-DC converters 106. When the stack 900 operates in its safe mode, each node is a member of either the first or second subset.

[0306] In the example node, the DC-DC converter 106 is implemented using a boost converter circuit, which will be referenced below. Figure 11 To describe, the boost converter circuit boosts the voltage of battery 104 to produce an output node output voltage greater than the voltage level of battery 104. For example, in the example BMS stack 900, each node includes: battery 104, providing a voltage of 4V; and a boost converter that nominally boosts the voltage to 5V. Furthermore, the example stack 900 includes two hundred nodes, enabling operation in normal operating mode (…). Figure 9A During this period, the total voltage across the fuel cell stack is 1000V. This is to ensure safety in mode (…). Figure 9D During this period, a safe output voltage level of 30V is achieved across the stack 900, with the isolating switch 256 of the first subset (6 nodes) closed and the isolating switch 256 of the second subset (remaining 194 nodes) open. When the stack 900 is in safe mode, the node membership in the first and second subsets can be changed. During the first time interval, for example, nodes N1 to N6 (not all shown) can be selected as members of the first subset, and the remaining nodes can be selected as members of the second subset. During the second time interval, for example, nodes N7 to N... 12(Not shown) is a member of the first subset, and the remaining nodes can be selected as members of the second subset; during the third time interval, node N can be selected. 13 To N 18 (Not shown) as a member of the first subset, and the remaining nodes can be selected as members of the second subset; etc. In some implementations, node membership changes periodically or in response to a signal to change one or more of the stack voltage or stack current.

[0307] In an alternative implementation, each DC-DC converter 106 is capable of reducing the stack voltage, and the stack 900 operates in its safe mode by causing each DC-DC converter 106 to reduce its output voltage, such that V stack This is a safe voltage. For example, if N equals 100, resulting in one hundred nodes, then in safe mode, each DC-DC converter 106 can convert its individual battery voltage to a node voltage of 0.1 volts, making V... stack It is a safe voltage of 10 volts.

[0308] During normal operation, the stack 900 can be used to provide the specified voltage required to supply normal power levels to electrical loads, for example, approximately 600V for US residential battery energy storage systems and approximately 1000V to 1500V for utility-scale applications. In bypass mode, the output voltage of each node is short-circuited, such that the entire stack is connected to electrical ground. Alternatively, in float charge mode or open-circuit mode, all nodes can remain float charge (i.e., not connected to ground) or at a predetermined impedance value. Both bypass and float charge modes can be safe, but because the nodes are inoperable, there is no visibility into whether an individual node or stack is actually operable (i.e., ready for normal operation). Safe mode allows observation of the operation of each node to determine appropriate system operation and interconnections while maintaining overall safe voltage and power levels. Additionally, the rotation of active nodes in safe mode, for example by changing the membership of the first and second subsets as described above, facilitates rapid identification of non-functional nodes, as the stack output voltage drop during active node rotation indicates one or more non-functional nodes. Therefore, safety mode is particularly useful for installation and maintenance. Safety mode can also benefit firefighters by eliminating the potential for firefighters to be exposed to dangerous high voltages and currents.

[0309] Figure 9E This is an explanation Figures 9A to 9D Example fault response state diagram 950 shows how the example fuel cell stack 900 switches between operating mode, bypass mode, float charge mode, and safety mode. Code instruction C SM1 and C SM2Used to configure the stack controller (not shown) and the main controller (not shown) to switch between modes. State 952 is the normal charge / discharge mode, which in some implementations is equivalent to the above regarding... Figure 9A The operating modes discussed. The fuel cell stack 900 can switch from normal charge / discharge mode 952 to any of bypass mode 954, float charge mode 956, and safety mode 958, such as in response to fault detection. Examples of such faults include, but are not limited to, arcing faults or failures in the communication subsystem or other subsystems of the energy storage system 200. For example, the fuel cell stack 900 can be configured to switch the defective fuel cell stack from normal charge / discharge mode 952 to float charge mode 956 in response to the detection of a series arcing fault in the defective stack, such as using method 550 discussed above. Operation in float charge mode extinguishes the arc in the defective stack while allowing the remaining stacks to continue operating, thereby ensuring safety and minimizing the impact of the arcing fault on system operation. Alternatively, such as using method 650 described above, the system can be configured to switch all fuel cell stacks from normal charge / discharge mode 952 to any of bypass mode 954, float charge mode 956, and safety mode 958 in response to the detection of a system-level series arcing fault. Any of the bypass mode 954, float charge mode 956, and safety mode 958 will extinguish the arc, although the system will be inoperable until the system defect is repaired.

[0310] Furthermore, using the method 750 described above, the fuel cell stack 900 can be configured to switch the defective fuel cell stack from normal charging / discharging mode 952 to float charging mode 956 in response to the detection of a parallel arc fault within the defective fuel cell stack. Operation in float charging mode extinguishes the arc in the defective fuel cell stack while allowing the remaining fuel cell stacks to continue operating, thereby ensuring safety and minimizing the impact of the arc fault on system operation. Additionally, the fuel cell stack can be configured as described above... Figure 7A The discussed method identifies the location of the arc to accelerate the repair of the defective fuel cell stack. Furthermore, such as using the method 850 described above, the system can be configured to switch all fuel cell stacks from normal charge / discharge mode 952 to any one of bypass mode 954, float charge mode 956, and safety mode 958 in response to the detection of a system-level parallel arc fault. Any of bypass mode 954, float charge mode 956, and safety mode 958 will extinguish the arc, although the system will be inoperable until the system defect is repaired. Additionally, fuel cell stack 900 can switch from normal charge / discharge mode 952 to any one of bypass mode 954, float charge mode 956, and safety mode 958 in response to user commands (such as preparation for system maintenance or servicing), in response to an emergency near the system (e.g., fire), or for any other reason.

[0311] The fuel cell stack 900 can also switch from any of the bypass mode 954, float charge mode 956, and safety mode 958 to normal charge / discharge mode 952, such as when it is determined that the system is safely free from arcing, short circuits, or other defects, or in response to a user command. Additionally, although in Figure 9E As not shown, some embodiments of the fuel cell stack 900 can switch from any of the bypass mode 954, float charge mode 956, and safety mode 958 to any of the other modes without first switching to the normal charge / discharge mode 952.

[0312] In some implementations, each BMS node has multiple operating modes, such as normal charging / discharging mode, bypass mode, and float charging mode. For example, consider again... Figure 9A The fuel cell stack 900. In some embodiments, each BMS node N1 to N of the fuel cell stack 900 N It can operate independently of other BMS nodes of the fuel cell stack 900 in normal charge / discharge mode, bypass mode, or float charge mode. At a given BMS node N1 to N of the fuel cell stack 900... N In the above, (a) the normal operating mode is characterized by the disconnecting switch 256 being closed and the node output short-circuit switch 257 being open, (b) the bypass mode is characterized by the disconnecting switch 256 being open and the node output short-circuit switch 257 being closed, and (c) the float charge mode is characterized by each of the disconnecting switch 256 and the node output short-circuit switch 257 being open.

[0313] Therefore, the operating modes of the fuel cell stack 900 can be determined by its constituent BMS nodes N1 to N. N The various operating modes are used to characterize it. For example, the bypass mode of the fuel cell stack 900 might be characterized by each BMS node N1 to N... N Operating in its bypass mode, such as Figure 9B As shown. Additionally, the float charge mode of the fuel cell stack 900 may be characterized by BMS nodes N1 to N... N One or more of them operate in their float charging mode, such as Figure 9C As shown in the diagram. Furthermore, the safety mode of the fuel cell stack 900 may be characterized in that some BMS nodes of the fuel cell stack 900 operate in their normal charge / discharge modes, while other BMS nodes of the fuel cell stack 900 operate in their bypass modes, such as... Figure 9D As shown.

[0314] It should be understood that this system and method not only improves safety but also achieves significant additional advantages. For example, in some embodiments, it is not necessary to shut down the entire energy storage system in response to a fault or other anomaly. Instead, the problematic portion of the energy storage system can be disabled and / or isolated from the rest of the energy storage system, allowing the energy storage system to continue operating safely, albeit with reduced capacity. For example, in some embodiments, the defective battery 104 can be isolated from the healthy battery 104 by disconnecting the isolating switch 256, and the individual nodes of the battery can be bypassed by closing the node output short-circuit switch 257, thereby enabling the energy storage system to operate safely with the defective battery 104 isolated from the healthy battery 104. Additionally, the defective battery 104 can optionally be safely discharged, such as using the means discussed below. As another example of isolating a defective portion of the energy storage system from the rest of the system, the defective stack can be isolated from the healthy stack by switching the defective stack from its normal charge / discharge mode 952 to its float charge mode 956, thereby disabling the defective stack without interfering with the operation of the healthy stack. Therefore, this system and method help minimize downtime of energy storage systems, which improves the reliability and economy of energy storage systems by reducing or even eliminating the need for redundant energy storage systems.

[0315] Furthermore, this system and method advantageously help minimize ongoing operation and maintenance costs of energy storage systems, which can be five to ten percent of the total lifecycle cost of conventional energy storage systems. For example, Safety Mode 958 allows portions, or even the entire energy storage system, to continue operating in a low-power state regardless of the presence of a fault or other anomaly. This low-power operation significantly facilitates fault location, as fault location in a powered system is generally much easier than in a non-powered system. Additionally, as mentioned above, some embodiments can identify the location of arcing faults in the energy storage system, which can further accelerate fault diagnosis and repair. Moreover, some embodiments are configured to automatically send a signal to a third party (e.g., an energy storage system service company) in response to the occurrence of a fault or other anomaly. This signal can, for example, identify the type and location of the fault, enabling the third party to remotely assess the urgency of fault repair and the need for replacement components, further promoting efficient and economical operation and maintenance of the energy storage system.

[0316] Furthermore, the fact that the energy storage system can continue to operate safely despite a fault reduces the need for unscheduled system maintenance and repair, which also helps minimize operating and maintenance costs. For example, a defective battery in a conventional energy storage system might require shutting down the entire system, necessitating an emergency service call to replace the defective battery and bring the energy storage system back to operation. Conversely, in some embodiments of this system and method, the defective battery 104 can be isolated from healthy batteries 104, allowing the energy storage system to continue operating safely, thereby postponing battery replacement until a scheduled maintenance call.

[0317] Furthermore, the system and method of this invention are capable of taking more aggressive safety measures than conventional energy storage systems, thereby further enhancing safety. Specifically, the identification of faults or other anomalies in conventional energy storage systems typically requires shutting down the entire system as described above. Therefore, conventional energy storage systems must conservatively identify faults to prevent false fault identification, which necessitates the expensive and inconvenient shutdown of the entire system. In contrast, this system and method allow faults or other anomalies to be addressed by shutting down only a portion of the energy storage system, such as a single node or a single fuel cell stack, allowing the rest of the system to continue operating. Therefore, the cost of false fault identification in this energy storage system is lower than in conventional energy storage systems, allowing for more aggressive fault detection.

[0318] Identifying unsafe batteries

[0319] Batteries themselves can become unsafe. For example, lithium plating, dendrite growth, and mechanical short circuits can all lead to intermittent cell-level arcing or short circuits. Continued operation of an unsafe battery is dangerous and can lead to hazardous current levels, thermal runaway, and fire. As used in this paper, an unsafe battery is one whose electrical performance indicates an unsafe failure risk even if the battery device has not exceeded absolute limits and therefore has not failed. Early identification of unsafe nodes allows for preventative actions such as disconnecting the battery from the node, discharging the battery to a safe state of charge or voltage, shutting down the entire system, and replacing the unsafe battery before a potentially catastrophic failure occurs. The electrical signatures of unsafe risks can be identified by the battery's unexpected electrical response to external stimuli such as master controller commands and load changes. Battery models (e.g., thermal, electrochemical, and equivalent circuit models (e.g., state of charge (SOC) models) are used to describe the expected electrical response. The electrical signatures of unsafe cells can also be experimentally determined by observing electrical signals and inducing known failure modes in similar cells. Machine learning algorithms can be trained on experimentally acquired data or fleet-wide field data to improve the sensitivity and accuracy of insecurity risk detection algorithms or reduce the harmful labeling of false faults.

[0320] Figure 10 This is a schematic diagram illustrating method 1050 for detecting an unsafe battery before it enters thermal runaway. Method 1050 is performed, for example, by processor circuitry 217-2 of node 100, stack controller 210 of the battery stack, and / or main controller 212. In step 1052, cell voltage (V), current (I), and temperature (T) are measured, such as using the methods described above. Figure 1 The technology discussed. Step 1054 compares the instantaneous VIT measurement with the expected values ​​of V, I, and T from the battery model, and if any instantaneous value exceeds the expected range, the battery is flagged as unsafe. For example, a voltage reading lower than expected and / or a current reading higher than expected and / or a temperature reading higher than expected can indicate an intermittent short circuit or arc (state 1056), prompting a fault response to disconnect the unsafe battery from the system, and / or, depending on the severity of the fault response, an emergency cell discharge (described below).

[0321] If the instantaneous VIT reading is not an indication of an unsafe battery, the rates of change of V, I, and T are compared with expected values ​​of V, I, and T from the battery model or other thresholds to identify an unsafe battery. For example, rapid changes in V, I, and / or T that are not interpreted by commands from the main controller 212 or changes in the load 204 are flagged as unsafe batteries, prompting a fault response.

[0322] The order of steps 1054 and 1058 can be interchanged, or the two steps can be performed simultaneously. Step 1058 can also be performed in the frequency domain, where the fast Fourier transforms of the V, I, and T sequences are compared with the expected values.

[0323] For example, the desired values ​​considered in steps 1054 and 1058 are determined from the model of battery 104. Each battery may have its own model or "digital twin." In some embodiments, the battery 104 model is derived at least in part from VIT measurements of the BMS node of the energy storage system 200. Examples of battery 104 models include, but are not limited to, an equivalent circuit model of battery 104, a state-of-charge model of battery 104, and a thermal model of battery 104. In some embodiments, one or more of the models are refined as used, such as by using Kalman filtering or a similar process, wherein battery 104 model parameters are estimated and subsequently updated in response to measurements.

[0324] Furthermore, some embodiments of the energy storage system 200 use data from other energy storage systems to perform one or more functions, such as generating battery models, detecting unsafe batteries, detecting arcing faults, or determining fault responses. For example, in some embodiments, the stack controller 210 instance and / or the main controller 212 send system data 1502 to the battery data processing engine 1500, such as... Figure 15 As shown. In some embodiments, the battery data processing engine 1500 is external to the energy storage system 200. For example, the battery data processing engine 1500 may be implemented by a computer server or by a distributed computing system external to the energy storage system 200. In some other embodiments, the battery data processing engine 1500 is part of the energy storage system 200. For example, in a particular embodiment, the battery data processing engine 1500 is implemented by the main controller 212.

[0325] System data 1502 sent to battery data processing engine 1500 represents one or more characteristics of energy storage system 200. For example, system data 1502 may include node VIT data, fault status, and / or information about energy storage system 200, such as the type of battery 104 in energy storage system 200, the configuration of battery 104 in energy storage system 200, manufacturing information of battery 104 in energy storage system 200, operational history of battery 104 in energy storage system 200, maintenance history of battery 104 in energy storage system 200, etc. Optionally, system data 1502 may be encrypted, compressed, and / or preprocessed (e.g., to identify various degradation mechanisms) before being sent from energy storage system 200 to battery data processing engine 1500.

[0326] Battery data processing engine 1500 compares system data 1502 with aggregated data 1504 to find common characteristics between the two datasets. Aggregated data 1504 includes data from multiple energy storage systems, such as from tens, hundreds, or even thousands of energy storage systems. Battery data processing engine 1500 may optionally add information it receives from energy storage systems to aggregated data 1504, causing aggregated data 1504 to grow over time. Examples of common characteristics between system data 1502 and aggregated data 1504 include, but are not limited to: batteries operating under the same or similar conditions, batteries with the same or similar operating durations, batteries with the same or similar energy production, batteries from a common manufacturing batch, batteries with the same or similar installations, batteries stored under the same or similar conditions, batteries with the same or similar maintenance history, and batteries with similar prominent characteristics of arcing faults. In some implementations, battery data processing engine 1500 uses self-learning methods (e.g., machine learning, deep learning, or even multimodal machine learning) to identify common characteristics between system data 1502 and aggregated data 1504.

[0327] The battery data processing engine 1500 then identifies data applicable to the energy storage system 200 (applicable data 1506) based on common characteristics between system data 1502 and aggregated data 1504. More specifically, the battery data processing engine 1500 identifies data in aggregated data 1502 that is associated with an energy storage system having common characteristics with the energy storage system 200 as applicable data 1506. For example, the battery data processing engine 1500 can identify data from an energy storage system having the same type of battery as the energy storage system 200 as applicable data 1506. As another example, the battery data processing engine 1500 can identify data from an energy storage system operating under conditions similar to those of the energy storage system 200 as applicable data 1506. Applicable data 1506 can be indirectly or directly related to data associated with an energy storage system having common characteristics with the energy storage system 200. In some implementations, the battery data processing engine 1500 uses self-learning methods (e.g., machine learning, deep learning, or even multimodal machine learning) to identify applicable data 1506 from aggregated data 1504.

[0328] The battery data analysis engine 1500 sends applicable data 1506 to the energy storage system 200, such as to the main controller 212 and / or one or more stack controllers 210. The energy storage system 200 may optionally use the applicable data 1506 to manage one or more aspects of the energy storage system 200. For example, in a particular embodiment, the main controller 212 and / or the stack controller 210 use the applicable data 1506 to build or refine a model of the battery 104, thereby controlling battery charging / discharging or for unsafe battery identification and associated fault response. As another example, in some embodiments, the main controller 212 and / or the stack controller 210 use the applicable data 1506 to detect and respond to arcing faults. For example, the applicable data 1506 may include distinctive features of arc faults and associated fault responses for an energy storage system similar to energy storage system 200, and such distinctive features may be used in decision steps 556, 656, 754 and / or 856 and mitigation steps 560, 662, 664, 758 and / or 860 in arc fault detection methods 550, 650, 750 and 850, respectively. For example, low-pass filter values ​​used in decision steps 556, 656, 754 and / or 856 may be determined at least in part based on the distinctive features of arc faults in the applicable data 1506 to achieve an arc fault detection distribution optimized for detecting the distinctive features of arc faults in the applicable data 1506. As another example, the decision to switch from normal charge / discharge mode 952 to one of bypass mode 954, float charge mode 956 and safety mode 958 (Figure 9) can be based at least in part on previous experience with similar fault conditions determined by battery data analysis engine 1500 and transmitted to energy storage system 200 via applicable data 1506.

[0329] Unsafe discharge nodes

[0330] Batteries deemed unsafe may remain dangerous as long as they are charged. For example, overcharged batteries increase the risk of short circuits and arcing failures, and are more likely to experience thermal runaway than undercharged batteries. Therefore, it is desirable to discharge unsafe batteries or batteries that are being charged or discharged uncontrollably by a faulty system. The following discharge circuit enables a node to safely discharge the battery within the node itself. The example discharge circuit is configured to discharge battery 104 in response to determining that a battery or system as described above is unsafe, or in response to a command to discharge the battery (such as preparing to perform system maintenance or servicing).

[0331] Figure 11This is an illustrative circuit diagram of a first example bidirectional DC-DC converter circuit 1100 used as a DC-DC converter 106 in example node 100. The DC-DC converter circuit 1100 functions as a boost converter during discharge and a buck converter during charging. The first converter 1100 includes a first transistor switch 1102, which includes a first parasitic body diode 1118. The first switch 1102 is connected between a positive power bus terminal 251 and circuit node X. The source and drain terminals of the first transistor switch 1102 are selected such that the first body diode 1118 conducts current from circuit node X to the positive power bus terminal 251. In other words, the first parasitic diode 1118 has a forward bias diode current flow direction from circuit node X toward the positive power bus terminal 251. The DC-DC converter 1100 includes a second switch 1110, which includes a second parasitic body diode 1120. The second switch 1110 is connected between circuit node X and a negative battery device terminal 253. The second parasitic diode 1120 has a forward bias diode current flow direction from the negative battery device / bus terminal 253 toward circuit node X. The first switch 1102 and the second switch 1110, together with the inductor 1122, form the core of a DC-DC converter that operates as a boost converter when discharging the battery 104 and as a buck converter when charging the battery 104.

[0332] The third transistor switch 1134 includes a third parasitic diode 1142, which is connected in series between the positive battery terminal 252 and circuit node X, and in series with inductor 1122. The third parasitic diode 1142 has a forward bias diode current flow direction from circuit node X toward battery 104. The third switch 1134 serves as a battery isolation (or disconnect) switch, therefore the third switch 1134 is Figure 1 The embodiment of the battery isolating switch 256. Inductor 1122 is electrically connected between the third circuit switch 1134 and circuit node X. Capacitor 1189 is connected between the second terminal of inductor 1122 and the negative battery terminal 253. Capacitor 1194 is connected between the positive terminal 251 and the negative terminal 253.

[0333] An optional fourth transistor switch 1172, including a fourth parasitic body diode 1180, is connected between the positive power bus terminal 251 and the negative battery device / bus terminal 253. The fourth body diode 1180 has a forward-biased diode current flow direction from the negative battery device / bus terminal 253 toward the positive power bus terminal 251. The fourth switch 1172 functions as a node output short-circuit switch to provide continuity of the series node when the battery is disconnected. The function of switch 1172 is available as long as the third switch 1134 is open. L After the slope has risen to zero, it is replaced by conducting switches 1102 and 1110. Therefore, the fourth switch 1172 is... Figures 9A to 9D The implementation of switch 257. The DC-DC converter may also include... Figure 1 The soft short-circuit switch 259 and resistor 261 ( Figure 11 (Not shown in the image).

[0334] The DC-DC converter 1100 also includes an auxiliary discharge circuit 1182, which provides current-limiting auxiliary circuitry to safely discharge the battery 104. The auxiliary discharge circuit includes a fifth transistor switch 1186, which includes a body diode 1192 and is electrically connected in series with a resistor 1184, the value of which is selected to limit the discharge current to an acceptable value. During auxiliary discharge operation, a third switch 1134 is turned off (open) to isolate the battery 104 from the inductor 1122. The fifth switch 1186 is turned on (closed) so that current can flow from the battery 104 through the positive battery terminal 252 and through the resistor 1184 to the negative battery terminal 253 to safely discharge the battery 104 through the resistor 1184. The third switch 1134 may be implemented by one or more different transistors, or by another type of switching device, such as a relay or contactor, without departing from the scope of the invention.

[0335] Figure 12 This is an illustrative circuit diagram of a second example bidirectional DC-DC converter circuit 1200 used as a DC-DC converter 106 in example node 100. For the sake of efficiency, the second converter circuit 1200 will not be described further. Figure 12The components corresponding to the components of the first converter circuit 1000. The battery discharge circuit 1220 includes: (a) a fifth switch 1286 having a parasitic diode 1292; and (b) a current control circuit 1293, which includes an amplifier circuit 1294 coupled to control the first switch 1286 to discharge the battery 104 with a selectable current. In one embodiment, the current is fixed to discharge a fully charged cell within a predetermined time period (e.g., 1 hour (1C discharge) to 15 minutes (4C discharge)). In another embodiment, the current is controlled to regulate the battery or circuit temperature, thereby facilitating rapid but safe discharge. During auxiliary discharge mode operation, the third switch 1134 is turned off (open), and the amplifier 1294 controls the fifth switch 1286 as a current source to safely discharge the battery 104, as described above.

[0336] Optionally, the processor 117-2, the stack controller 210, and / or the main controller 212 can utilize existing loads and take the battery offline during the most speculative time to achieve safe discharge while still supplying energy to the load 204. In this embodiment, no additional discharge circuitry is required. Once an unsafe battery is identified, it will not be charged. Instead, it will be offline until it is discharged to a safe SOC or voltage, such as below approximately 20% of its state of charge, through one or more regular discharge cycles. The discharge can optionally be controlled at a rate different from that of a healthy cell. For example, a higher discharge rate may be considered necessary for a battery stored at a lower SOC that carries a greater risk of failure. A lower discharge rate may be considered necessary for a battery with abnormally high series resistance to avoid self-heating. Once safely discharged, the battery can remain bypassed at its low SOC until inspection and possible repair or replacement. The discharge rate of battery 104 can be controlled, for example, by controlling the respective DC-DC converters 106 of battery 104 to change the node output voltage, i.e., the voltage across output port 260. For example, by controlling the DC-DC converter 106 to make the node output voltage greater than the voltage of other nodes in the stack, the discharge rate of the battery 104 can be increased, and by controlling the DC-DC converter 106 to make the node output voltage less than the voltage of other nodes in the stack, the discharge rate of the battery 104 can be reduced.

[0337] Figure 13A This is an illustrative circuit diagram of a simplified example bidirectional DC-DC converter circuit 1300 used in example node 100. Details of the converter circuit will be provided from... Figure 11 Understand from the description. Figures 13B to 13C This is an illustrative signal diagram representing the process of discharging an unsafe battery device. For example... Figure 13BAs shown, during normal operation, battery 104 is charged and discharged by the load. Conversely, during discharge operation mode, DC-DC converter 1300 operates to discharge unsafe battery 104 to load 204 as quickly as possible while avoiding catastrophic failure. During charging operation, unsafe battery 104 is bypassed by DC-DC converter 1300, such as by off switch 1134 and on switch 1172, so that battery 104 is not recharged when other battery devices are recharged, as... Figure 13C As shown. Battery 104 continues to discharge in subsequent discharge cycles until the desired safe voltage or state of charge is reached. This unidirectional operation of the DC-DC converter 1300, i.e., causing battery 104 to participate only in the discharge cycle, can be particularly useful when it is desirable to minimize the cost of addressing defective batteries, such as when battery 104 may only be defective or only slightly defective.

[0338] Refer again Figure 1 and Figure 2 In some embodiments, the processor circuit 217-2, the fuel cell controller 210, and / or the main controller 212 are configured to send commands to the load 204, and the load 204 is configured to perform one or more actions in response to these commands. For example, in a particular embodiment, one or more of the processor circuit 217-2, the fuel cell controller 210, and the main controller 212 are configured to send commands to the load 204 to increase its power consumption, and the load 204 is configured to accelerate the safe discharge of one or more batteries 104 accordingly in response to a signal determining that the battery is unsafe and / or in response to a signal performing controlled discharge of battery 104. Furthermore, in some embodiments, the processor circuit 217-2, the fuel cell controller 210, and / or the main controller 212 are configured to send commands to the load 204 to set the voltage V. L and / or current I L The magnitude of the discharge allows the energy storage system 200 to further control the discharge of one or more batteries 104. In some embodiments, one or more of the processor circuitry 217-2, the stack controller 210, and the main controller 212 are configured to dynamically control the voltage V via commands to the load 204 (e.g., based on one or more battery or node parameters). L and / or current I LThe magnitude of these parameters. Examples of these parameters include, but are not limited to, battery 104 temperature, battery 104 state of charge, battery 104 degradation state, battery 104 health state, and battery 104 safety characteristics. Additionally, the processor circuitry 217-2, the stack controller 210, and / or the main controller 212 may be configured to command the load 204 to reduce power consumption and regulate the voltage V in response to one or more batteries 104 being in a safe state (e.g., in response to the battery voltage or battery state of charge exceeding a threshold). L and / or current I L .

[0339] Furthermore, in some embodiments where load 204 is a photovoltaic device or photovoltaic system, processor circuit 217-2, stack controller 210, and / or main controller 212 are configured to command nodes in one or more stacks to apply voltage V. L The value is set high enough to transfer power from one or more batteries 104 to the photovoltaic device or system 104, thereby facilitating the safe discharge of the batteries 104. Furthermore, in these embodiments, the processor circuitry 217-2, the stack controller 210, and / or the main controller 212 are optionally configured to command nodes in one or more stacks to transfer current I during the safe discharge of the batteries 104. L The amplitude is set to the desired value, thereby accelerating the discharge of battery 104 without overloading the photovoltaic device or system.

[0340] Node isolation

[0341] Figure 14A This illustrates an example series node N of a fuel cell stack lacking reverse voltage fault mode protection in the disconnected state. N and N N-1 This is a partial illustrative circuit diagram. In the float charge off state, all switches are off (open). Figure 14B This illustrates the reverse voltage short-circuit fault during the float charge disconnection state. Figure 14A Node N of the fuel cell stack N and N N-1 An illustrative circuit diagram showing the flow of short-circuit current between them. In other words, Figure 14B This indicates that although isolating switch 1434 is open, reverse voltage (a short circuit from the positive terminal of a battery to the negative terminal of the node below) is not protected against. This unprotected reverse voltage causes a cell short circuit (through the body diode 1420 of switch 1410 and the body diode 1418 of switch 1402, carrying a large current), which could lead to thermal runaway and fire.

[0342] Each node N includes a battery 104 with a positive terminal 1462 and a negative terminal 1464, capacitors 1489, 1448, and 1466, an inductor 1422, a first switch 1402 including a body diode 1418, a second switch 1410 including a body diode 1420, and a third switch 1434 including a body diode 1442. For clarity, some examples of these components are not labeled. The first switch 1402, the second switch 1410, and the inductor 1422 form the core of a DC-DC converter 1460, which includes an output port 260 configured for electrical connection in series with an additional node N. The third switch 1434 is electrically connected between the positive terminal 1462 of the battery 104 and the DC-DC converter 1460 and is configured to selectively connect and disconnect the battery 1434 from the DC-DC converter 1460. In some alternative embodiments, a third switch 1434 replaces the electrical connection between the negative terminal 1464 of the battery 104 and the DC-DC converter 1460. In some embodiments, the processor circuitry 217-2 optionally controls the switching of each node by means of the stack controller 210 and / or the main controller 212.

[0343] refer to Figure 14A During normal operation, each battery 104 provides a voltage, for example, VBAT = approximately 3.6V. When in the off state, each of the first switch 1402, the second switch 1410, and the third switch 1434 is turned off (open). In the example stack, if at the output terminals of each node, at the positive output terminal 251 of each node... N-1 and negative output terminal 253 N-1 If a negative voltage of -1V is applied between nodes N, then node N... N-1 Potential failure. The critical node voltage is given by the sum of the forward voltages of the two diodes, 1418 and 1420 (2 x approximately 0.5V). If at node N... N-1 If the critical node voltage is reached, a large current can flow through the two diodes 1418 and 1420, eventually causing a voltage surge at the example node N. N-1 and / or node N N Permanent damage. For example, node N. N The battery 104 discharges rapidly, which could lead to thermal runaway.

[0344] refer to Figure 14B During the example failure mode, node N N Positive battery device terminal 252 N Short-circuited to node N N-1 negative power terminal 253 N-1The negative voltage across diodes 1418 and 1420 becomes equivalent to the voltage of battery 104, for example, approximately 3.6V. First body diode 1418 and second body diode 1420 are forward biased, and uncontrolled current can flow through them. An abnormal electrical connection 1468 causes a short-circuit current 1470, which flows from node N. N Positive battery device terminal 252 N The current flows to node N through diodes 1418 and 1420. N-1 negative power terminal 253 N-1 An abnormal electrical connection 1468 can be caused by a short circuit, such as a loose wire segment that short-circuits both. Node N N Battery 104 feeds current and power to a short circuit. If the short circuit is applied for a sufficiently long time (approximately a few seconds), it can cause a catastrophic failure, such as a fire. In an alternative embodiment where a third switch 1434 is electrically connected between the negative terminal 1464 of battery 104 and the DC-DC converter 1460, if the positive battery terminal 252... N Short circuit to node N N-1 Even if each of the first switch 1402, the second switch 1410, and the third switch 1434 is turned off (opened), the short-circuit current can still be present at node N at the negative terminal 1464 of the battery. N and N N-1 Flowing between.

[0345] Figure 14C This shows an example series connection node N of the BMS stack. N and N N-1 The illustrative circuit diagram includes a first example of a reverse voltage fault mode protection circuit in the form of an isolating switch 1452 that is in an open state during fault mode operation, the isolating switch 1452 including a body diode 1458. Figure 14D This illustrates the situation during a short-circuit fault from a reverse voltage while the circuit is in the open state. Figure 14C An illustrative circuit diagram showing the blocked short-circuit current between the nodes of the fuel cell stack. For the sake of efficiency description, Figures 14C to 14D The shown with Figures 14A to 14B The circuit components described herein will not be explained further.

[0346] refer to Figure 14C Example node N N-1 The system includes a disconnector switch 1452, which has a first terminal 1454 and a second terminal 1456. The first terminal 1454 of the disconnector switch 1452 is connected to a second switch 1410. The second terminal 1456 of the disconnector switch 1452 is connected to node N. N-1 The negative power terminal 1464 of battery 104. Therefore, disconnecting switch 1452 is connected to node N.N-1 The negative power terminal 1464 of battery 104 is connected in series. The advantages of this series arrangement are: ground-referenced gate drive facilitates the implementation of an n-channel switch; the switch can also be low-voltage, with a rated voltage slightly higher than the battery voltage. Isolating switch 1452 is oriented such that its body diode 1458 does not provide a path for short-circuit current 1471. Specifically, the positive terminal of body diode 1458 is connected to the negative terminal 1464 of battery 104, and the negative terminal of body diode 1458 is connected to DC-DC converter 1460. Alternatively, isolating switch 1452 can be replaced with a switching device that does not include a body diode. Similarly, example node N... N (And each of the other nodes in the BMS stack) includes an isolating switch 1452 and an associated body diode 1458, which is similarly connected.

[0347] Reference Figure 14D During the example failure mode, example node N N Positive power bus terminal 252 N Having a connection with node N N-1 negative power terminal 253 N-1 An abnormal electrical connection 1468. Abnormal connection 1468 generates an abnormal current 1471 from node N. N Positive battery device terminal 252 N The current flows to node N through diodes 1418 and 1420. N-1 negative power terminal 253 N-1 The risk. However, as shown by dashed line 1473, open-circuit disconnector 1452 prevents short-circuit current from flowing from node N. N The positive power terminal 252 of battery 104 N Flow to node N N-1 negative power terminal 253 N-1 Therefore, node N N Battery 104 is not fed a short circuit and protects the battery pack. Isolating switch 1452 closes during normal charge / discharge operation.

[0348] Disconnector 1452 can be replaced by one or more alternative disconnectors in connection with node N. N-1 In the event of a short circuit, the disconnecting switch also prevents current from flowing through node N. N The battery 104 flows. For example, Figure 14E This shows an example series connection node N of the BMS stack. N and N N-1 The illustrative circuit diagram includes a second example of a reverse voltage fault mode protection circuit in the form of an isolating switch 1472 that is in an open state during fault mode operation, the isolating switch 1472 including a body diode 1478. For the sake of efficiency, Figure 14E The shown with Figures 14A to 14D The circuit components described herein will not be explained further. Example node N N-1 This includes a disconnector switch 1472 having a first terminal 1474 and a second terminal 1476. The first terminal 1474 of the disconnector switch 1472 is connected to node N. N-1 The first terminal 1404 of the first switch 1402. The second terminal 1476 of the disconnecting switch 1472 is connected to node N. N negative power terminal 253 N The isolating switch 1472 is oriented such that its body diode 1478 does not provide a path for the short-circuit current 1485. Specifically, the cathode of the body diode 1478 is connected to the output port 260. N-1 The positive extreme 251 N-1 Alternatively, the disconnector switch 1472 can be replaced by a switching device that does not include a body diode.

[0349] During normal node operation, the current from battery 104 flows discontinuously through disconnector switch 1472; conversely, current flows through disconnector switch 1472 only when switch 1410 is in its open or non-conducting state. Therefore, assuming equivalent operating conditions, the root mean square (RMS) value of the current flowing through disconnector switch 1472 will be less than that flowing through... Figure 14D The RMS value of the current of the disconnector switch 1452. Therefore, for the same switch conduction loss, Figure 14E The disconnector switch 1472 can have a higher performance than Figure 14D The isolating switch 1452 has a larger on-resistance. In some implementations, the isolating switch 1472 is an n-channel MOSFET or a p-channel MOSFET, depending on the gate driver circuit design.

[0350] Still referencing Figure 14E In the example failure mode, example node N N Positive bus terminal 252 N Having a connection with node N N-1 negative power terminal 253 N-1 An abnormal electrical contact 1468. The abnormal connection 1468 generates an abnormal current 1485 from node N. N Positive battery device terminal 252 N The current flows to node N through diodes 1418 and 1420. N-1 negative power terminal 253 N-1 The risk. However, as shown by dashed line 1489, open circuit switch 1472 prevents potential current 1485 from flowing from node N. N The positive terminal of battery 104 is 252. N Flow to node N N-1negative power terminal 253 N-1 Therefore, node N N Battery 104 cannot supply power during a short circuit. Node N N Optionally, it also includes nodes similar to N. N-1 The disconnector switch 1472 (not shown).

[0351] In embodiments where the third switch 1434 is electrically connected between the negative terminal 1464 of battery 104 and the DC-DC converter 1460, rather than between the positive terminal 1462 of battery 104 and the DC-DC converter 1460, the isolating switch 1472 also prevents short-circuit current from flowing. For example, Figure 14F This shows an example of a series connection of node N in a BMS stack. N and N N-1 The illustrative circuit diagram includes a second example of a reverse voltage fault mode protection circuit in the form of an isolating switch 1472 that is open during fault mode operation. For the sake of efficiency, Figure 14F The shown with Figures 14A to 14E The circuit components described herein will not be explained further. In this example, the third switch 1434 is electrically connected between the negative terminal 1464 of the battery 104 and the DC-DC converter 1460.

[0352] In the example failure mode, example node N N Positive bus terminal 252 N Having a connection with node N N-1 An abnormal electrical contact 1490 occurs at the negative terminal 1464 of battery 104. This abnormal connection 1490 generates an abnormal current 1495 from node N. N Positive battery device terminal 252 N Through node N N-1 Diode 1418 and node N N The risk of diode 1420. However, as shown by dashed line 1489, open circuit switch 1472 prevents potential current 1495 from flowing.

[0353] Those skilled in the art will understand that variations can be made to the exemplary energy storage system, battery management system nodes, and associated methods without departing from the spirit and scope of this disclosure. For example, based on the principle of circuit duality, variations of the exemplary DC-DC converter can be achieved by appropriately replacing inductors with capacitors (and vice versa), replacing current with voltage, and replacing series configurations with parallel configurations, while still achieving the desired functionality, and such variations are considered to be within the scope of this disclosure as taught herein. For example, modifications can be made... Figure 11The DC-DC converter 1100 is configured such that it operates as a boost converter during battery 104 charging and as a buck converter during battery 104 discharging. As another example, the DC-DC converter 1100 can be replaced by a buck-boost converter to achieve boost and buck conversion of battery voltage to node voltage.

[0354] Additional examples

[0355] The above method can also be applied to energy management systems with BMS nodes that do not regulate node voltage or stack voltage. For example, the method can be applied to an energy management system with BMS nodes that do not include power converters. As another example, the method can be applied to an energy management system with BMS nodes that include DC-DC converters configured to handle differential power, i.e., power differences between BMS nodes or power differences between individual cells of a BMS node, rather than the total power of the entire BMS node or the total power of individual cells. For example, the DC-DC converter can be configured to transfer differential power between adjacent BMS nodes, between a BMS node and a bus, or between a BMS node and a load or power source.

[0356] Taking the BMS node offline, such as by operating the BMS node in bypass mode, can change the stack voltage in embodiments where the BMS node does not regulate the node voltage or stack voltage. However, if the stack voltage was a relatively small percentage before taking the BMS node offline, such a change in the stack voltage may be acceptable. For example, a change in the stack voltage caused by taking the BMS node offline is acceptable if it is less than 10 percent or less than 5 percent of the stack voltage before taking the BMS node offline. Additionally, in energy management systems that include one or more alternative means for regulating voltage, such as stack-level power converters (e.g., inverters or other loads electrically connected to the stack, internal or external) capable of connecting parallel stacks or stack interfaces to loads with regulated voltages, a change in the stack voltage caused by taking the BMS node offline may be acceptable.

[0357] The following is for reference. Figures 16 to 35 The discussion focuses on several examples of how the above methods can be applied to battery energy management systems with BMS nodes that do not regulate node or stack voltage. However, it should be understood that the above methods are not limited to these example applications.

[0358] Figure 16This is an illustrative block diagram of an example energy storage system 1600 including a fuel cell stack 1602, an electrical load 1604, and a controller 1606. The energy storage system 1600 may include additional fuel cell stacks 1602 without departing from the scope of the invention, and each fuel cell stack 1602 does not need to have the same configuration. The electrical load 1604 is electrically connected to the fuel cell stack 1602, and the electrical load 1604 is similar to... Figure 2 The electrical load 1604 is a battery. Therefore, the electrical load 1604 can both receive power from the energy storage system 1600 and supply power to the energy storage system 1600 to charge the battery. The controller 1606 is configured to control the energy storage system 1600, and for clarity, the connections between the controller 1606 and other components of the energy storage system 1600 are not shown. Although the controller 1606 is described as a single component, some implementations of the controller 1606 are implemented by two or more sub-components that do not need to be located in a common location. For example, some implementations of the controller 1606 are at least partially embodied in a distributed computing system. Although the controller 1606 is described as separate from the battery stack 1602, the controller 1606 may be at least partially integrated with the battery stack 1602. In certain embodiments, the controller 1606 is similar to... Figure 2 The fuel cell stack controller 210 and / or Figure 2 The main controller 212. In some embodiments, the controller 1606 is implemented at least in part by the individual node controllers (not shown) of each BMS node 1608, wherein the node controllers of all BMS nodes 1608 jointly perform at least some of the functions of the controller 1606.

[0359] The stack 1602 comprises N BMS nodes 1608, where N is an integer greater than 1. In this document, a specific instance of a project can be referred to by using a number in parentheses (e.g., BMS node 1608(1)), while a number without parentheses refers to any such project (e.g., BMS node 1608). Each BMS node 1608 comprises a positive output node 1610 and a negative output node 1612, and the BMS nodes 1608 are connected in series in the stack 1602 such that the positive output node 1610 of one BMS node 1608 is electrically connected to the negative output node 1612 of the adjacent BMS node 1608. For example, the positive output node 1610(1) of BMS node 1608(1) is electrically connected to the negative output node 1612(2) of the adjacent BMS node 1608(2). Each BMS node 1608 has a respective node voltage V across its output nodes 1610 and 1612. n .

[0360] Each BMS node 1608 also includes a battery 1614, an isolating switch 1616, and a bypass switch 1618. Within each BMS node 1608, the battery 1614 and the isolating switch 1616 are connected in series between the positive output node 1610 and the negative output node 1612, and the bypass switch 1618 is connected in series between the positive output node 1610 and the negative output node 1612. Each BMS node 1608 optionally also includes a discharge switch 1620 and a current source 1622 connected in parallel with the battery 1614 of that node. A controller 1606 is configured to control each switch 1616, 1618, and 1620 to open or close the switch, although the connection between the controller 1606 and the switches is not shown for clarity.

[0361] BMS node 1608 does not include a DC-DC converter, therefore BMS node 1608 cannot regulate their respective node voltages V. n In some implementations, each BMS node 1608 can operate in multiple possible operating modes under the control of the controller 1606. For example, in some implementations, each BMS node 1608 can operate in a normal charging / discharging mode, a bypass mode, and a float charging mode. A normal charging / discharging mode for a given BMS node 1608 is characterized by: (a) the isolating switch 1616 being closed, (b) the bypass switch 1618 being open, and (c) the discharge switch 1620 being open. A bypass mode for a given BMS node 1608 is characterized by: (a) the isolating switch 1616 being open, and (b) the bypass switch 1618 being closed. Although not strictly necessary, the discharge switch 1620 can be open in a bypass node. A float charging mode for a given BMS node 1608 is characterized by each of the isolating switch 1616, the bypass switch 1618, and the discharge switch 1620 being open.

[0362] All BMS nodes 1608 do not need to operate in the same operating mode at a given time. For example, assume that all BMS nodes 1608 are operating in their respective normal charge / discharge modes, and at time t a A fault occurs in BMS node 1608(2). Controller 1606 can respond to the fault by switching BMS mode 160(2) to its bypass mode or its float charge mode, while the remaining BMS nodes 1608 continue to operate in their normal charge / discharge modes. Detecting and responding to faults at the BMS node level can be much faster than detecting and responding to faults at the stack level or system level.

[0363] The fuel cell stack 1602 can also operate in one or more of several operating modes under the control of the controller 1606. For example, the fuel cell stack 1602 can operate in one or more of the following modes under the control of the controller 1606: normal charge / discharge mode, float charge mode, bypass mode, and safety mode. Some embodiments of the controller 1606 are configured to switch the fuel cell stack 1602 between operating modes, as described above. Figure 9E The fault response state is described in Figure 950. The normal charge / discharge mode of the stack 1602 is characterized by each BMS node 1608 operating in its normal charge / discharge mode such that the battery 1614 is connected in series within the stack 1602. The float charge mode of the stack 1602 is characterized by one or more BMS nodes 1608 operating in their float charge mode such that one or more batteries 1614 are isolated, and the stack 1602 has a high impedance as seen from the electrical load 1604. The bypass mode is characterized by each BMS node 1608 operating in its bypass mode such that the battery 1614 is isolated, and the stack 1602 has a low impedance as seen from the electrical load 1604. The safety mode is characterized by (a) a first subset of BMS nodes 1608 operating in their normal charge / discharge mode; and (b) a second subset of BMS nodes 1608 operating in their bypass mode, wherein all BMS nodes 1608 are part of either the first or second subset, in a manner similar to the above description. Figure 9D The methods discussed.

[0364] Additionally, some embodiments of the energy storage system 1600 are configured to safely discharge the battery 1614 under the control of the controller 1606, for example, in response to a determination, as described above, that the battery or energy storage system is unsafe, or in response to a command to discharge the battery (such as preparing to perform system maintenance or servicing). For example, some embodiments of the energy storage system 1600 are configured to safely discharge the battery 1614 of a given BMS node 1608 by disconnecting the isolation switch 1616 of the BMS node and by closing the discharge switch 1620 of the BMS node, such that the current source 1622 of the BMS node safely discharges the battery. The BMS nodes 1608 can be modified to include alternative circuitry for the safe discharge of their respective batteries 1614. For example, the current source 1622 can be replaced by individual resistors, such that each BMS node 1608 includes similar... Figure 11 The discharge circuit of the discharge circuit. As another example, the discharge switch 1620 and current source 1622 can be replaced by individual transistors driven by respective amplifiers, such that each BMS node 1608 includes a discharge circuit similar to the discharge circuit of the discharge circuit. Figure 12 The discharge circuit of the discharge circuit.

[0365] The energy storage system 1600 can also be configured to operate in a manner similar to the above. Figures 13A to 13C The discussed method safely discharges battery 1614 via electrical load 1604. For example, battery 1614(2) can be safely discharged by: (a) during the charging mode of energy storage 1600, causing BMS node 1608(2) to operate in its bypass mode, and (b) during the discharging mode of energy storage system 1600, causing BMS node 1608(2) to operate in its normal charge / discharge node, thereby safely discharging battery 1614(2) into electrical load 1604 during one or more charge / discharge cycles of energy storage system 1600.

[0366] The above-described methods for detecting and mitigating arc faults can also be applied to the energy storage system 1600 or its variants. For example, Figure 5A 500 fuel cell stack Figure 6A and 6B fuel cell stack and Figure 8A and 8B The fuel cell stack can be made from Figure 16 This is implemented using an instance of the 1602 fuel cell stack. Additionally, Figure 7A Nodes N1 to N N This can be achieved using an instance of BMS node 1608. Additionally, Figure 5B and Figure 7B The method can be applied to the 1600 energy storage system, while Figure 6C and Figure 8C The method can be applied to implementations of an energy storage system 1600 that includes multiple stacks 1602.

[0367] Furthermore, the aforementioned measurement synchronization method can be applied to energy storage system 1600 or its variants. For example, Figure 3A Methods and Figure 3B The method can be applied to alternative implementations of the energy storage system 1600, wherein the BMS node 1608 further includes circuitry for acquiring measurements, such as voltage, current, and / or temperature measurements, and telemetry circuitry for transmitting and / or receiving measurement information. As another example, Figure 4A , Figure 4B and Figure 4C The concept can be applied to alternative implementations of the energy storage system 1600, wherein the BMS node 1608 also includes measurement circuitry and telemetry circuitry.

[0368] Refer again Figure 16Some embodiments of the energy storage system 1600 are also configured to selectively isolate individual BMS nodes 1608, i.e., selectively switch individual BMS nodes 1608 between their normal charge / discharge modes and bypass modes. The controller 1606 is optionally configured to selectively isolate individual BMS nodes 1608, for example, to ensure that all batteries 1614 reach a given state of charge (e.g., minimum or maximum state of charge) approximately simultaneously. For example, suppose battery 1614(2) is in a higher state of charge than the other batteries 1614 in the stack 1602 during a charging cycle of the energy storage system 1600. The controller 1606 can cause BMS node 1608(2) to operate in its bypass mode for a portion of the charging cycle, which allows the charging of the other batteries 1614 in the stack 1602 to catch up with battery 1614(2), potentially enabling all batteries 1614 in the stack 1602 to reach their maximum state of charge at approximately the same time. As another example, suppose that battery 1614(1) discharges faster than the other batteries 1614 of stack 1602 during a discharge cycle of energy storage system 1600. Controller 1606 can cause BMS node 1608(1) to operate in its bypass mode for a portion of the discharge cycle, which reduces the discharge rate of battery 1614(1) and thereby potentially allows all batteries 1614 to reach minimum state of charge approximately simultaneously.

[0369] The following is about Figures 17 to 35 The discussion pertains to an example energy storage system in which the BMS node includes individual DC-DC converters for transferring differential power, such as directly between BMS nodes, between a BMS node and a bus, or between a BMS node and a load or power supply. However, it should be understood that other topologies capable of differential power transfer are also within the scope of this disclosure.

[0370] Figures 17 to 35 The example energy storage system includes switching devices and current sources similar to BMS node 1608. Therefore, Figures 17 to 35 Some implementations of the fuel cell stack in energy storage systems can achieve similar results to those described above. Figure 16 The methods discussed operate in normal charging / discharging mode and in one or more of float charging mode, bypass mode, and safety mode. Figures 17 to 35 Some implementations of BMS nodes in energy storage systems can also be similar to those described above. Figure 16 The discussed methods operate in normal charging / discharging mode and in one or more of float charging and bypass modes. Additionally, Figures 17 to 35 Some implementations of energy storage systems can be similar to those described above. Figure 16The methods discussed safely discharge the battery and / or detect and mitigate arcing faults. Furthermore, the measurement synchronization methods discussed above can be applied in a similar manner to how synchronization methods are used. Figure 16 The energy storage system 1600 is applied in this way. Figures 17 to 35 Example energy storage system.

[0371] Figure 17 This is an illustrative block diagram of an example energy storage system 1700 including fuel cell stack 1702, electrical load 1704, and controller 1706. The energy storage system 1700 may include additional fuel cell stacks 1702 without departing from the scope of the invention, and each fuel cell stack 1702 does not need to have the same configuration. The electrical load 1704 is electrically connected to the fuel cell stack 1702, and the electrical load 1704 is similar to... Figure 2 The electrical load 204. Therefore, the electrical load 1704 can receive power from the energy storage system 1700 and can also supply power to the energy storage system 1700 to charge the battery. The controller 1706 is configured to control the energy storage system 1700, and for clarity, the connections between the controller 1706 and other components of the energy storage system 1700 are not shown. Although the controller 1706 is described as a single component, some embodiments of the controller 1706 are implemented by two or more sub-components that do not need to be located in a common location. For example, some embodiments of the controller 1706 are at least partially embodied in a distributed computing system. Although the controller 1706 is described as separate from the fuel cell stack 1702, the controller 1706 can be at least partially integrated with the fuel cell stack 1702. In certain embodiments, the controller 1706 is similar to... Figure 2 The fuel cell stack controller 210 and / or Figure 2 The main controller 212. In some embodiments, controller 1706 is implemented at least in part by individual node controllers (not shown) of each BMS node 1708, wherein the node controllers of all BMS nodes 1708 jointly perform at least some of the functions of controller 1706.

[0372] The fuel cell stack 1702 includes N BMS nodes 1708, where N is an integer greater than 1. Each BMS node 1708 includes a positive output node 1710, a negative output node 1712, and a transfer node 1713. The BMS nodes 1708 are connected in series in the fuel cell stack 1702, such that the positive output node 1710 of one BMS node 1708 is electrically connected to the negative output node 1712 of the adjacent BMS node 1708. For example, the positive output node 1710(1) of BMS node 1708(1) is electrically connected to the negative output node 1712(2) of the adjacent BMS node 1708(2).

[0373] Each BMS node 1708 also includes a battery 1714, an isolating switch 1716, a bypass switch 1718, an upper transfer switch 1724, and a lower transfer switch 1726. Within each BMS node 1708, the battery 1714 and the isolating switch 1716 are connected in series between the positive output node 1710 and the negative output node 1712, and the bypass switch 1718 is connected between the positive output node 1710 and the negative output node 1712. Furthermore, within each BMS node 1708, the upper transfer switch 1724 is connected between the positive output node 1710 and the transfer node 1713, and the lower transfer switch 1726 is connected between the transfer node 1713 and the negative output node 1712. Each BMS node 1708 optionally also includes a discharge switch 1720 and a current source 1722 connected in parallel with the battery 1714 of that node.

[0374] The energy storage system 1700 also includes N-1 transfer capacitors 1728, each of which is electrically connected between transfer nodes 1713 of adjacent BMS nodes 1708. For example, transfer capacitor 1728(1) is electrically connected between transfer node 1713(1) of BMS node 1708(1) and transfer node 1713(2) of adjacent BMS node 1708(2). The transfer capacitors 1728 are used, for example, to transfer charge between batteries 1714 of adjacent BMS nodes 1708, as described below.

[0375] Controller 1706 is configured to control each of switches 1716, 1718, 1720, 1724, and 1726 to cause the switches to open or close, although the connection between controller 1706 and the switches is not shown for clarity. Isolating switch 1716 and bypass switch 1718 are similar to... Figure 16 The isolating switch 1616 and bypass switch 1618 are included. Therefore, the controller 1706 is configured to control the isolating switch 1716 and bypass switch 1718 to cause the stack 1702 and / or BMS node 1708 to switch between operating modes (e.g., normal charge / discharge mode, float charge mode, bypass mode, and safety mode) in the same manner as discussed above with respect to the energy storage system 1600. Additionally, the discharge switch 1720 and current source 1722 are similar to... Figure 16 The discharge switch 1620 and the current source 1622. Therefore, the controller 1706 is configured to control the discharge switch 1720 in accordance with the above. Figure 16 The battery 1714 is safely discharged in the same manner discussed. Furthermore, some embodiments of the energy storage system 1700, such as those omitting the discharge switch 1720 and current source 1722, are configured to discharge in a manner similar to that described above. Figures 13A to 13C The method discussed is to safely discharge battery 1714 via electrical load 1704.

[0376] Furthermore, controller 1706 is also configured to control the upper transfer switch 1724 and lower transfer switch 1726 of BMS node 1708 to transfer charge between batteries 1714 of adjacent BMS node 1708 via transfer capacitor 1728. For example, Figure 18 and Figure 19 A two-step process is illustrated, in which charge is transferred from battery 1714(2) to battery 1714(1) via transfer capacitor 1728(1). For clarity, in Figure 18 and Figure 19 The dashed lines depicting BMS nodes 1708(1) and 1708(2) are omitted. Energy storage system 1700 in... Figure 18 and Figure 19 The charge transfer process operates in normal charge / discharge mode. Therefore, as Figure 18 and Figure 19 As shown, isolating switch 1716 is closed, bypass switch 1718 is open, and discharge switch 1720 is open.

[0377] Figure 18 The energy storage system 1700 is shown during the first step, with upper transfer switches 1724(1) and 1724(2) closed and lower transfer switches 1726(1) and 1726(2) open. Therefore, transfer capacitor 1728(1) is charged from battery 1714(2), as shown by dashed line 1802, which illustrates the current between battery 1714(2) and transfer capacitor 1728(1). Figure 19 The energy storage system 1700 is shown during the second step, where the upper transfer switches 1724(1) and 1724(2) are open, and the lower transfer switches 1726(1) and 1726(2) are closed. Therefore, the transfer capacitor 1728(1) is discharged to the battery 1714(1), as shown by dashed line 1902, which indicates the current between the transfer capacitor 1728(1) and the battery 1714(1). Therefore, Figure 18 and Figure 19 The two steps shown together transfer charge from cell 1714(2) to cell 1714(1) via transfer capacitor 1728(1). Similar steps can be performed to transfer charge between cells 1714 of other adjacent BMS nodes 1708 of stack 1702.

[0378] Additionally, some embodiments of the energy storage system 1700 are configured to safely discharge battery 1714, such as by transferring the charge of battery 1714 to one or more other batteries 1714 in the stack 1702, in response to a battery being identified as unsafe. For example, suppose battery 1714(2) is identified as unsafe. Some embodiments of the energy storage system 1700 are configured to safely discharge battery 1714(2) by transferring the charge of battery 1714(2) to battery 1714(1), such as by using the above-mentioned... Figure 18 and Figure 19 The process discussed.

[0379] As described above, the energy storage system 1700 is configured to transfer charge between cells 1714 of adjacent BMS nodes 1708 via transfer capacitor 1728. The energy storage system 1700 can be modified to transfer charge between cells via a stack-level transfer capacitor, which can be accessed by all BMS nodes of the stack via the stack's energy transfer bus. For example, Figure 20 This is an illustrative block diagram of an example energy storage system 2000 including a fuel cell stack 2002, an electrical load 2004, and a controller 2006. The energy storage system 2000 may include additional fuel cell stacks 2002 without departing from the scope of the invention, and each fuel cell stack 2002 does not need to have the same configuration. The electrical load 2004 is electrically connected to the fuel cell stack 2002, and the electrical load 2004 is similar to... Figure 2 The electrical load 2004. Therefore, the electrical load 2004 can receive power from the energy storage system 2000 and supply power to the energy storage system 2000 to charge the battery. The controller 2006 is configured to control the energy storage system 2000, and for clarity, the connections between the controller 2006 and other components of the energy storage system 2000 are not shown. Although the controller 2006 is described as a single component, some embodiments of the controller 2006 are implemented by two or more sub-components that do not need to be located in a common location. For example, some embodiments of the controller 2006 are at least partially embodied in a distributed computing system. Although the controller 2006 is described as separate from the fuel cell stack 2002, the controller 2006 can be at least partially integrated with the fuel cell stack 2002. In certain embodiments, the controller 2006 is similar to... Figure 2 The fuel cell stack controller 210 and / or Figure 2 The main controller 212. In some embodiments, the controller 2006 is at least partially embodied by the individual node controllers (not shown) of each BMS node 2008, wherein the node controllers of all BMS nodes 2008 jointly perform at least some of the functions of the controller 2006.

[0380] The fuel cell stack 2002 includes N BMS nodes 2008 and transfer capacitors 2028, where N is an integer greater than 1. Each BMS node 2008 includes a positive output node 2010, a negative output node 2012, and a battery node 2013. The BMS nodes 2008 are connected in series in the fuel cell stack 2002, such that the positive output node 2010 of one BMS node 2008 is electrically connected to the negative output node 2012 of the adjacent BMS node 2008. For example, the positive output node 2010(1) of BMS node 2008(1) is electrically connected to the negative output node 2012(2) of the adjacent BMS node 2008(2). The transfer capacitors 2028 are electrically connected between a first transfer node 2032 and a second transfer node 2034, and the transfer nodes 2032 and 2034 together form an energy transfer bus accessible by each BMS node 2008. As described below, the transfer capacitor 2028 is used to temporarily store charge while transferring charge between batteries 2014 of BMS node 2008.

[0381] Each BMS node 2008 also includes a battery 2014, an isolating switch 2016, a bypass switch 2018, an upper transfer switch 2024, and a lower transfer switch 2026. Within each BMS node 2008, the battery 2014 and the isolating switch 2016 are connected in series between the positive output node 2010 and the negative output node 2012, such that the battery 2014 and the isolating switch 2016 are connected at the battery node 2013, and the bypass switch 2018 is electrically connected between the positive output node 2010 and the negative output node 2012. Furthermore, within each BMS node 2008, the upper transfer switch 2024 is electrically connected between the battery node 2013 and the second transfer node 2034, and the lower transfer switch 2026 is electrically connected between the negative output node 2012 and the first transfer node 2032. Each BMS node 2008 may also include a discharge switch 2020 and a current source 2022 electrically connected in parallel with the node's battery 2014.

[0382] Controller 2006 is configured to control each of switches 2016, 2018, 2020, 2024, and 2026 to cause the switches to open or close, although the connection between controller 2006 and the switches is not shown for clarity. Isolating switch 2016 and bypass switch 2018 are similar. Figure 16 The disconnector switch 1616 and bypass switch 1618 are included. Therefore, the controller 2006 is configured to control the disconnector switch 2016 and bypass switch 2018 to cause the fuel cell stack 2002 and / or BMS node 2008 to switch between operating modes (such as normal charge / discharge mode, float charge mode, bypass mode, and safety mode) in the same manner as discussed above with respect to the energy storage system 1600. Additionally, the disconnector switch 2020 and current source 2022 are similar to... Figure 16 The disconnector switch 1620 and the current source 1622. Therefore, the controller 2006 is configured to control the disconnector switch 2020 in accordance with the above. Figure 16 The battery 2014 is safely discharged in the same manner discussed. Furthermore, some embodiments of the energy storage system 2000, such as those omitting the discharge switch 2020 and current source 2022, are configured to discharge in a manner similar to that described above. Figures 13A to 13C The method discussed is to safely discharge battery 2014 via electrical load 2004.

[0383] Furthermore, controller 2006 is also configured to control the upper transfer switch 2024 and lower transfer switch 2026 of BMS node 2008 to transfer charge between batteries 2014 of BMS node 2008 via transfer capacitor 2028. Figure 17 Compared to the energy storage system 1700, the energy storage system 2000 is capable of transferring charge between cells at any BMS node 2008 (including non-adjacent BMS nodes 2008) in two steps. For example, Figure 21 and Figure 22 A two-step process is shown, in which charge is transferred from battery 2014(1) to battery 2014(N). For clarity, in Figure 21 and Figure 22 The dashed lines depicting BMS node 2008 are omitted. Energy storage system 2000 in... Figure 21 and Figure 22 During the charge transfer process, it operates in normal charge / discharge mode. Therefore, as Figure 21 and Figure 22 As shown, isolating switch 2016 is closed, bypass switch 2018 is open, and discharge switch 2020 is open.

[0384] Figure 21 The energy storage system 2000 is shown during the first step, wherein transfer switches 2024(1) and 2026(1) are closed, and all other transfer switches 2024 and 2026 are open. Therefore, transfer capacitor 2028 is charged from battery 2014(1), as shown by dashed line 2102, which indicates the current between battery 2014(1) and transfer capacitor 2028. Figure 22 The energy storage system 2000 is shown during the second step, where transfer switches 2024(N) and 2026(N) are closed, and all other transfer switches 2024 and 2026 are open. Therefore, transfer capacitor 2028 is discharged to battery 2014(N), as shown by dashed line 2202, which indicates the current between transfer capacitor 2028 and battery 2014(N). Thus, Figure 21 and Figure 22The two steps shown transfer charge from cell 2014(1) to cell 2014(N) via transfer capacitor 2028. Similar steps can be performed to transfer charge between cells 2014 of other BMS nodes 2008 of stack 2002.

[0385] Additionally, some embodiments of the energy storage system 2000 are configured to safely discharge the battery 2014, such as by transferring the charge of the battery 2014 to one or more other batteries 2014 in the stack 2002, in response to the battery being identified as unsafe. For example, suppose the battery 2014(1) is identified as unsafe. Some embodiments of the energy storage system 2000 are configured to safely discharge the battery 2014(1) by transferring the charge of the battery 2014(1) to the battery 2014(N) and / or one or more other batteries 2014, such as by using the above-mentioned... Figure 21 and Figure 22 The process discussed or a similar process.

[0386] Charge can be transferred between BMS node cells using energy storage devices other than capacitors (or other than capacitors). For example, Figure 23 This is an illustrative block diagram of an example energy storage system 2300 including a fuel cell stack 2302, an electrical load 2304, and a controller 2306. The energy storage system 2300 may include additional fuel cell stacks 2302 without departing from the scope of the invention, and each fuel cell stack 2302 does not need to have the same configuration. The electrical load 2304 is electrically connected to the fuel cell stack 2302, and the electrical load 2304 is similar to... Figure 2 The electrical load 204. Therefore, the electrical load 2304 can receive power from the energy storage system 2300 and can also supply power to the energy storage system 2300 to charge the battery. The controller 2306 is configured to control the energy storage system 2300, and for clarity, the connections between the controller 2306 and other components of the energy storage system 2300 are not shown. Although the controller 2306 is described as a single component, some embodiments of the controller 2306 are implemented by two or more sub-components that do not need to be located in a common location. For example, some embodiments of the controller 2306 are at least partially embodied in a distributed computing system. Although the controller 2306 is described as separate from the fuel cell stack 2302, the controller 2306 may be at least partially integrated with the fuel cell stack 2302. In certain embodiments, the controller 2306 is similar to... Figure 2 The fuel cell stack controller 210 and / or Figure 2The main controller 212. In some embodiments, the controller 2306 is implemented at least in part by the individual node controllers (not shown) of each BMS node 2308, wherein the node controllers of all BMS nodes 2308 jointly perform at least some of the functions of the controller 2306.

[0387] The fuel cell stack 2302 includes N BMS nodes 2308, where N is an integer greater than 1. Each BMS node 2308 includes a positive output node 2310, a negative output node 2312, and a transfer node 2313. The BMS nodes 2308 are connected in series in the fuel cell stack 2302, such that the positive output node 2310 of one BMS node 2308 is electrically connected to the negative output node 2312 of the adjacent BMS node 2308. For example, the positive output node 2310(1) of BMS node 2308(1) is electrically connected to the negative output node 2312(2) of the adjacent BMS node 2308(2).

[0388] Each BMS node 2308 also includes a battery 2314, an isolating switch 2316, a bypass switch 2318, a first transfer switch 2324, and an inductor 2328. Although the inductor 2328 is shown as a discrete component, it may be partially or completely represented as the parasitic inductance of the circuit including the inductor. Within each BMS node 2308, the battery 2314 and the isolating switch 2316 are connected in series between the positive output node 2310 and the negative output node 2312, and the bypass switch 2318 is connected between the positive output node 2310 and the negative output node 2312. Additionally, within each BMS node 2308, the first transfer switch 2324 is connected between the positive output node 2310 and the transfer node 2313, and the inductor 2328 is connected between the transfer node 2313 and the negative output node 2312. Each BMS node 2308 may optionally also include a discharge switch 2320 and a current source 2322 electrically connected in parallel with the battery 2314 of the node.

[0389] The energy storage system 2300 also includes N-1 second transfer switches 2326, each of which is electrically connected between a transfer node 2313 of a BMS node 2308 and a negative output node 2312 of an adjacent BMS node 2308. For example, a second transfer switch 2326(1) is electrically connected between a transfer node 2313(2) of a BMS node 2308(2) and a negative output node 2312(1) of an adjacent BMS node 2308(1). The second transfer switches 2326 are used, for example, to transfer charge between batteries 2314 of adjacent BMS nodes 2308, as described below. Although the second transfer switches 2326 are described as being outside the BMS node 2308, they may optionally be located inside the BMS node 2308. For example, in an alternative embodiment (not shown), each BMS node 2308, in addition to BMS node 2308(N), includes a second transfer switch 2326 electrically connected between the negative output node 2312 of the BMS node 2308 and the transfer node 2313 of the adjacent BMS node 2308. As another example, in another alternative embodiment (not shown), each BMS node 2308, in addition to BMS node 2308(1), includes a second transfer switch 2326 electrically connected between the transfer node 2313 of the BMS node and the negative output node 2312 of the adjacent BMS node 2308.

[0390] Controller 2306 is configured to control each of switches 2316, 2318, 2320, 2324, and 2326, thereby causing the switches to open or close, although the connection between controller 2306 and the switches is not shown for clarity. Isolating switch 2316 and bypass switch 2318 are similar to... Figure 16 The isolating switch 1616 and bypass switch 1618 are included. Therefore, the controller 2306 is configured to control the isolating switch 2316 and bypass switch 2318 so that the fuel cell stack 2302 and / or BMS node 2308 switch between operating modes (e.g., normal charge / discharge mode, bypass mode, and safety mode) in the same manner as discussed above with respect to the energy storage system 1600. Additionally, the discharge switch 2320 and current source 2322 are similar to... Figure 16 The discharge switch 1620 and the current source 1622. Therefore, the controller 2306 is configured to control the discharge switch 2320 in order to... Figure 16 The battery 2314 is safely discharged in the same manner discussed. Furthermore, some embodiments of the energy storage system 2300, such as those omitting the discharge switch 2320 and current source 2322, are configured to discharge in a manner similar to that described above. Figures 13A to 13C The method discussed is to safely discharge battery 2314 via electrical load 2304.

[0391] Furthermore, controller 2306 is also configured to control first transfer switch 2324 and second transfer switch 2326 to transfer charge between batteries 2314 of adjacent BMS nodes 2308 via inductor 2328. For example, Figure 24 and Figure 25 A two-step process is illustrated, in which charge is transferred from battery 2314(2) to battery 2314(1) via inductor 2328(2). For clarity, in Figure 24 and 25 The dashed lines depicting BMS nodes 2308(1) and 2308(2), as well as several reference numerals, are omitted from the attached diagram. The energy storage system 2300... Figure 24 and Figure 25 During the charge transfer process, it operates in normal charge / discharge mode. Therefore, as Figure 24 and 25 As shown, isolating switch 2316 is closed, bypass switch 2318 is open, and discharge switch 2320 is open.

[0392] Figure 24 The energy storage system 2300 is shown during the first step, where the first transfer switch 2324(2) is closed and all other transfer switches are open. Therefore, the inductor 2328(2) is charged from the battery 2314(2), as shown by dashed line 2402, which indicates the current between the battery 2314(2) and the inductor 2328(2). Figure 25 The energy storage system 2300 is shown during the second step, where the external second switch 2326(1) is closed and all other transfer switches are open. Therefore, the inductor 2328(2) is discharged to the battery 2314(1), as shown by dashed line 2502, which indicates the current between the inductor 2328(2) and the battery 2314(1). Therefore, Figure 24 and Figure 25 The two steps shown transfer charge from battery 2314(2) to battery 2314(1) via inductor 2328(2). Similar steps can be performed to transfer charge between batteries 2314 of other adjacent BMS nodes 2308 of the stack 2302.

[0393] Additionally, some embodiments of the energy storage system 2300 are configured to safely discharge battery 2314, such as by transferring the charge of battery 2314 to one or more other batteries 2314 in the stack 2302, in response to a battery being identified as unsafe. For example, suppose battery 2314(2) is identified as unsafe. Some embodiments of the energy storage system 2300 are configured to safely discharge battery 2314(2) by transferring the charge of battery 2314(2) to battery 2314(1), for example by using the above-mentioned... Figure 24 and Figure 25 The process discussed.

[0394] As another example, this is an energy storage system configured to use inductors to transfer charge. Figure 26 This is an illustrative block diagram of an example energy storage system 2600 including a fuel cell stack 2602, an electrical load 2604, and a controller 2606. The energy storage system 2600 may include additional fuel cell stacks 2602 without departing from the scope of the invention, and each fuel cell stack 2602 does not need to have the same configuration. The electrical load 2604 is electrically connected to the fuel cell stack 2602, and the electrical load 2604 is similar to... Figure 2 The electrical load 204. Therefore, the electrical load 2604 can both receive power from the energy storage system 2600 and supply power to the energy storage system 2600 to charge the battery. The controller 2606 is configured to control the energy storage system 2600, and for clarity, the connections between the controller 2606 and other components of the energy storage system 2600 are not shown. Although the controller 2606 is described as a single component, some embodiments of the controller 2606 are implemented by two or more sub-components that do not need to be located in a common location. For example, some embodiments of the controller 2606 are at least partially embodied in a distributed computing system. Although the controller 2606 is described as separate from the fuel cell stack 2602, the controller 2606 may be at least partially integrated with the fuel cell stack 2602. In certain embodiments, the controller 2606 is similar to... Figure 2 The fuel cell stack controller 210 and / or Figure 2 The main controller 212. In some embodiments, the controller 2606 is implemented at least in part by the individual node controllers (not shown) of each BMS node 2608, wherein the node controllers of all BMS nodes 2608 jointly perform at least some of the functions of the controller 2606.

[0395] The fuel cell stack 2602 includes a plurality of BMS nodes 2608 and a transfer inductor 2628. Although the fuel cell stack 2602 is shown as including four BMS nodes 2608, the fuel cell stack 2602 may include any number of BMS nodes, as long as the fuel cell stack 2602 includes at least two BMS nodes 2608. Each BMS node 2608 includes a positive output node 2610, a negative output node 2612, and a battery node 2613. The BMS nodes 2608 are electrically connected in series in the fuel cell stack 2602 such that the positive output node 2610 of one BMS node 2608 is electrically connected to the negative output node 2612 of the adjacent BMS node 2608. For example, the positive output node 2610(1) of BMS node 2608(1) is electrically connected to the negative output node 2612(2) of the adjacent BMS node 2608(2). Transfer inductor 2628 is electrically connected between first transfer node 2632 and second transfer node 2634, and transfer nodes 2632 and 2634 together form an energy transfer bus accessible to each BMS node 2608. As described below, transfer inductor 2628 is used to temporarily store energy while transferring charge between batteries 2614 of BMS node 2608.

[0396] Each BMS node 2608 also includes a battery 2614, an isolating switch 2616, a bypass switch 2618, an upper transfer switch 2624, and a lower transfer switch 2626. Within each BMS node 2608, the battery 2614 and the isolating switch 2616 are connected in series between the positive output node 2610 and the negative output node 2612, such that the battery 2614 and the isolating switch 2616 are connected at the battery node 2613, and the bypass switch 2618 is electrically connected between the positive output node 2610 and the negative output node 2612. Additionally, within each BMS node 2608, the upper transfer switch 2624 is electrically connected between the battery node 2613 and the second transfer node 2634, and the lower transfer switch 2626 is electrically connected between the negative output node 2612 and the first transfer node 2632. Each BMS node 2608 optionally also includes a discharge switch 2620 and a current source 2622 electrically connected in parallel with the battery 2614 of that node. The first BMS node 2608 in the fuel cell stack 2602 (i.e. Figure 26 The BMS node 2608(1) in the example also includes an additional transfer switch 2638 electrically connected between the negative output node 2612(1) and the second transfer node 2634.

[0397] Controller 2606 is configured to control each of switches 2616, 2618, 2620, 2624, 2626, and 2638 to cause the switches to open or close, although the connection between controller 2606 and the switches is not shown for clarity. Isolating switch 2616 and bypass switch 2618 are similar to... Figure 16 The isolating switch 1616 and bypass switch 1618 are included. Therefore, the controller 2606 is configured to control the isolating switch 2616 and bypass switch 2618 so that the stack 2602 and / or BMS node 2608 switch between operating modes (e.g., normal charge / discharge mode, bypass mode, and safety mode) in the same manner as discussed above with respect to the energy storage system 1600. Additionally, the discharge switch 2620 and current source 2622 are similar to... Figure 16 The discharge switch 1620 and the current source 1622. Therefore, the controller 2606 is configured to control the discharge switch 2620 in accordance with the above-mentioned... Figure 16 The battery 2614 is safely discharged in the same manner discussed. Furthermore, some embodiments of the energy storage system 2600, such as those omitting the discharge switch 2620 and current source 2622, are configured to discharge in a manner similar to that described above. Figures 13A to 13C The method discussed is to safely discharge battery 2614 via electrical load 2604.

[0398] Furthermore, controller 2606 is also configured to control transfer switches 2624, 2626, and 2638 of BMS node 2608 to transfer charge between batteries 2614 of BMS node 2608 via transfer inductor 2628. Figure 23 Compared to energy storage system 2300, energy storage system 2600 is capable of transferring charge between cells at any BMS node 2608 (including non-adjacent BMS nodes 2608) in two steps. For example, Figure 27 and Figure 28 Together, a two-step process is shown, in which charge is transferred from battery 2614(4) to battery 2614(1). For clarity, in Figure 27 and Figure 28 The dashed lines depicting BMS node 2608 and some reference numerals are omitted from the diagram. Energy storage system 2600 in... Figure 27 and Figure 28 During the charge transfer process, it operates in normal charge / discharge mode. Therefore, as Figure 27 and Figure 28 As shown, isolating switch 2616 is closed, bypass switch 2618 is open, and discharge switch 2620 is open.

[0399] Figure 27 The energy storage system 2600 is shown during the first step, wherein transfer switches 2624(4) and 2626(4) are closed and all other transfer switches are open. Therefore, transfer inductor 2628 is charged from battery 2614(4), as shown by dashed line 2702, which indicates the current between battery 2614(4) and transfer inductor 2628. Figure 28The energy storage system 2600 is shown during the second step, where transfer switches 2626(2) and 2638 are closed, and all other transfer switches are open. Therefore, transfer inductor 2628 is discharged to battery 2614(1), as shown by dashed line 2802, which indicates the current between transfer inductor 2628 and battery 2614(1). Therefore, Figure 27 and Figure 28 The two steps shown transfer charge from cell 2614(4) to cell 2614(1) via transfer inductor 2628. Similar steps can be performed to transfer charge between cells 2614 of other BMS nodes 2608 of stack 2602.

[0400] Additionally, some embodiments of the energy storage system 2600 are configured to safely discharge battery 2614, such as by transferring the charge of battery 2614 to one or more other batteries 2614 in the stack 2602, in response to a battery being identified as unsafe. For example, suppose battery 2614(4) is identified as unsafe. Some embodiments of the energy storage system 2600 are configured to safely discharge battery 2614(4) by transferring the charge of battery 2614(4) to battery 2614(1) and / or one or more other batteries 2614, such as by using the above-mentioned... Figure 27 and Figure 28 The process of discussion or a similar process.

[0401] Figure 29 This is an illustrative block diagram of an example energy storage system 2900 including a fuel cell stack 2902, an electrical load 2904, and a controller 2906. The energy storage system 2900 may include additional fuel cell stacks 2902 without departing from the scope of the invention, and each fuel cell stack 2902 does not need to have the same configuration. The electrical load 2904 is electrically connected to the fuel cell stack 2902, and the electrical load 2904 is similar to... Figure 2 The electrical load 204. Therefore, the electrical load 2904 can both receive power from the energy storage system 2900 and supply power to the energy storage system 2900 to charge the battery. The controller 2906 is configured to control the energy storage system 2900, and for clarity, the connections between the controller 2906 and other components of the energy storage system 2900 are not shown. Although the controller 2906 is described as a single component, some embodiments of the controller 2906 are implemented by two or more sub-components that do not need to be located in a common location. For example, some embodiments of the controller 2906 are at least partially embodied in a distributed computing system. Although the controller 2906 is described as separate from the fuel cell stack 2902, the controller 2906 can be at least partially integrated with the fuel cell stack 2902. In certain embodiments, the controller 2906 is similar to... Figure 2The fuel cell stack controller 210 and / or Figure 2 The main controller 212. In some embodiments, the controller 2906 is implemented at least in part by the corresponding node controller (not shown) of each BMS node 2908, wherein the node controllers of all BMS nodes 2908 jointly perform at least some of the functions of the controller 2906.

[0402] The fuel cell stack 2902 includes multiple BMS nodes 2908, transfer inductors 2928, and transfer capacitors 2929. Although the fuel cell stack 2902 is shown as including four BMS nodes 2908, the fuel cell stack 2902 may include any number of BMS nodes, as long as the fuel cell stack 2902 includes at least two BMS nodes 2908. Each BMS node 2908 includes a positive output node 2910, a negative output node 2912, and a battery node 2913. The BMS nodes 2908 are electrically connected in series in the fuel cell stack 2902 such that the positive output node 2910 of one BMS node 2908 is electrically connected to the negative output node 2912 of the adjacent BMS node 2908. For example, the positive output node 2910(1) of BMS node 2908(1) is electrically connected to the negative output node 2912(2) of the adjacent BMS node 2908(2). The transfer inductor 2928 and the transfer capacitor 2929 are connected in series between the first transfer node 2932 and the second transfer node 2934, and the transfer nodes 2932 and 2934 together form an energy transfer bus accessible to each BMS node 2908. As described below, the transfer inductor 2928 and the transfer capacitor 2929 are used for temporary energy storage while transferring charge between the batteries 2914 of the BMS node 2908.

[0403] Each BMS node 2908 includes a battery 2914, an isolating switch 2916, and a bypass switch 2918. Even-numbered BMS nodes 2908 also include an upper transfer switch 2924, and odd-numbered BMS nodes 2908 also include a lower transfer switch 2926. Within each BMS node 2908, the battery 2914 and the isolating switch 2916 are connected in series between the positive output node 2910 and the negative output node 2912, such that the battery 2914 and the isolating switch 2916 are connected at the battery node 2913, and the bypass switch 2918 is electrically connected between the positive output node 2910 and the negative output node 2912. Additionally, within each even-numbered BMS node 2908, the upper transfer switch 2924 is electrically connected between the battery node 2913 and the second transfer node 2934, and within each odd-numbered BMS node 2908, the lower transfer switch 2926 is electrically connected between the battery node 2913 and the first transfer node 2932. Each BMS node 2908 optionally also includes a discharge switch 2920 and a current source 2922 electrically connected in parallel with the node's battery 2914. The first BMS node 2908 in the fuel cell stack 2902 (i.e., Figure 29 The BMS node 2908(1) in the example also includes an additional transfer switch 2938 electrically connected between the negative output node 2912(1) and the second transfer node 2934.

[0404] Controller 2906 is configured to control each of switches 2916, 2918, 2920, 2924, 2926, and 2938, thereby opening or closing the switches, although the connection between controller 2906 and the switches is not shown for clarity. Isolating switch 2916 and bypass switch 2918 are similar. Figure 16 The isolating switch 1616 and bypass switch 1618 are included. Therefore, the controller 2906 is configured to control the isolating switch 2916 and bypass switch 2918 so that the stack 2902 and / or BMS node 2908 switch between operating modes (e.g., normal charge / discharge mode, float charge mode, bypass mode, and safety mode) in the same manner as discussed above with respect to the energy storage system 1600. Additionally, the discharge switch 2920 and current source 2922 are similar to... Figure 16 The discharge switch 1620 and the current source 1622. Therefore, the controller 2906 is configured to control the discharge switch 2920 in accordance with the above-mentioned... Figure 16 The battery 2914 is safely discharged in the same manner discussed. Furthermore, some embodiments of the energy storage system 2900, such as those omitting the discharge switch 2920 and current source 2922, are configured to discharge in a manner similar to that described above. Figures 13A to 13C The method discussed is to safely discharge battery 2914 via electrical load 2904.

[0405] Furthermore, controller 2906 is also configured to control transfer switches 2924, 2926, and 2938 of BMS node 2908 to transfer charge between batteries 2914 of BMS node 2908 via transfer inductor 2928 and transfer capacitor 2929. For example, Figure 30 and Figure 31 Together, a two-step process is shown, in which charge is transferred from battery 2914(4) to battery 2914(1). For clarity, in Figure 30 and Figure 31 The dashed lines depicting BMS node 2908 and several reference figures are omitted. Energy storage system 2900 in... Figure 30 and Figure 31 During the charge transfer process, it operates in normal charge / discharge mode. Therefore, isolating switch 2916 is closed, bypass switch 2918 is open, and discharge switch 2920 is open, as... Figure 30 and Figure 31 As shown.

[0406] Figure 30 The energy storage system 2900 is shown during the first step, wherein transfer switches 2924(4) and 2926(3) are closed, and all other transfer switches are open. Therefore, the resonant circuit consisting of transfer inductor 2928 and transfer capacitor 2929 is charged from battery 2914(4), as shown by dashed line 3002, which indicates the current between battery 2914(4) and the resonant circuit. Figure 31 The energy storage system 2900 is shown during the second step, where transfer switches 2926(1) and 2938 are closed, and all other transfer switches are open. Therefore, the resonant circuit is discharged to battery 2914(1), as shown by dashed line 3102, which indicates the current between the resonant circuit and battery 2914(4). Thus, Figure 30 and Figure 31 The two steps shown transfer charge from battery 2914(4) to battery 2914(1) via transfer inductor 2928 and transfer capacitor 2929. In some embodiments, controller 2906 is configured to, when the amplitude of the current flowing through the resonant circuit is at its peak, Figure 30 and Figure 31 The operation of the energy storage system 2900 is switched between various steps. It can perform operations related to... Figure 30 and Figure 31 The steps shown are similar to those for transferring charge between cells 2914 of other BMS nodes 2908 of the stack 2902.

[0407] Additionally, some embodiments of the energy storage system 2900 are configured to safely discharge battery 2914, such as by transferring the charge of battery 2914 to one or more other batteries 2914 in the stack 2902, in response to a battery being identified as unsafe. For example, suppose battery 2914(4) is identified as unsafe. Some embodiments of the energy storage system 2900 are configured to safely discharge battery 2914(4) by transferring the charge of battery 2914(4) to battery 2914(1) and / or to one or more other batteries 2914, for example by using the above-mentioned... Figure 30 and Figure 31 The process discussed or a similar process.

[0408] Figure 32 This is an illustrative block diagram of an example energy storage system 3200 including a fuel cell stack 3202, a system bus 3203, an electrical load 3204, and a controller 3206. Without departing from the scope of the invention, the energy storage system 3200 may include additional fuel cell stacks 3202, and each fuel cell stack 3202 does not need to have the same configuration. The electrical load 3204 is electrically connected to the fuel cell stack 3202 via the system bus 3203, and the electrical load 3204 is similar to... Figure 2 The electrical load 204. Therefore, the electrical load 3204 can both receive power from the energy storage system 3200 and supply power to the energy storage system 3200 to charge the battery. The controller 3206 is configured to control the energy storage system 3200, and for clarity, the connections between the controller 3206 and other components of the energy storage system 3200 are not shown. Although the controller 3206 is described as a single component, some embodiments of the controller 3206 are implemented by two or more sub-components that do not need to be located in a common location. For example, some embodiments of the controller 3206 are at least partially embodied in a distributed computing system. Although the controller 3206 is described as separate from the fuel cell stack 3202, the controller 3206 can be at least partially integrated with the fuel cell stack 3202. In certain embodiments, the controller 3206 is similar to... Figure 2 The fuel cell stack controller 210 and / or Figure 2 The main controller 212. In some embodiments, the controller 3206 is implemented at least in part by the individual node controllers (not shown) of each BMS node 3208, wherein the node controllers of all BMS nodes 3208 jointly perform at least some of the functions of the controller 3206.

[0409] The fuel cell stack 3202 includes N BMS nodes 3208, where N is an integer greater than 1. Each BMS node 3208 includes a positive output node 3210, a negative output node 3212, and a battery node 3213. The BMS nodes 3208 are connected in series in the fuel cell stack 3202, such that the positive output node 3210 of one BMS node 3208 is electrically connected to the negative output node 3212 of the adjacent BMS node 3208. For example, the positive output node 3210(1) of BMS node 3208(1) is electrically connected to the negative output node 3212(2) of the adjacent BMS node 3208(2).

[0410] Each BMS node 3208 also includes a battery 3214, a disconnector switch 3216, a bypass switch 3218, a primary transfer switch 3224, a secondary transfer switch 3226, and a transformer 3228. Within each BMS node 3208, the battery 3214 and the disconnector switch 3216 are connected in series between the positive output node 3210 and the negative output node 3212, such that the battery 3214 and the disconnector switch 3216 are connected at the battery node 3213, and the bypass switch 3218 is electrically connected between the positive output node 3210 and the negative output node 3212. Each transformer 3228 includes a primary winding P and a secondary winding S. Within each BMS node 3208, the primary winding P and the primary transfer switch 3224 are connected in series between the battery node 3213 and the negative output node 3212, and the secondary winding S and the secondary transfer switch 3226 are connected in series across the system bus 3203 (between the positive (+) and negative (-) nodes of the system bus 3203). Therefore, within each BMS node 3208, when the primary transfer switch 3224 is closed, the voltage V across the primary winding P is... P This is equal to the voltage across battery 3214. Additionally, when each secondary transfer switch 3226 of the winding is closed, the voltage V across each secondary winding S is... S Equal to the voltage V across load 3202 L Each BMS node 3208 may optionally also include a discharge switch 3220 and a current source 3222 electrically connected in parallel with the battery 3214 of that node.

[0411] Controller 3206 is configured to control each of switches 3216, 3218, 3220, 3224, and 3226, thereby causing the switches to open or close, although the connection between controller 3206 and the switches is not shown for clarity. Isolating switch 3216 and bypass switch 3218 are respectively similar to... Figure 16The isolating switch 1616 and bypass switch 1618 are included. Therefore, the controller 3206 is configured to control the isolating switch 3216 and bypass switch 3218 so that the fuel cell stack 3203 and / or BMS node 3208 switch between operating modes (e.g., normal charge / discharge mode, float charge mode, bypass mode, and safety mode) in the same manner as discussed above with respect to the energy storage system 1600. Additionally, the discharge switch 3220 and current source 3222 are respectively similar to... Figure 16 The discharge switch 1620 and the current source 1622. Therefore, the controller 3206 is configured to control the discharge switch 3220 in order to... Figure 16 The battery 3214 is safely discharged in the same manner discussed. Furthermore, some embodiments of the energy storage system 3200, such as those omitting the discharge switch 3220 and current source 3222, are configured to discharge in a manner similar to that described above. Figures 13A to 13C The method discussed is to safely discharge battery 3214 via electrical load 3204.

[0412] Furthermore, controller 3206 is also configured to control the primary transfer switch 3224 and secondary transfer switch 3226 of BMS node 3206 to transfer charge between batteries 3214 of adjacent BMS node 3208 via one or more energy storage elements electrically connected to system bus 3203. Possible energy storage elements electrically connected to system bus 3203 include, but are not limited to, the capacitor (not shown) of electrical load 3204, the batteries 3214 of stack 3203, and / or batteries of one or more additional stacks (not shown) electrically connected to system bus 3203. Within each BMS node 3208, transformer 3228, primary transfer switch 3224, and secondary transfer switch 3226 collectively form a flyback converter operating under the control of controller 3206. As is known in the art, the transformer of a flyback converter is configured to store energy within the transformer during the switching cycle of the flyback converter. Therefore, transformer 3228 has a sufficiently high leakage inductance to store energy for transfer between battery 3214 and energy storage elements electrically connected to system bus 3203.

[0413] Controller 3206 is configured to control transfer switches 3224 and 3226 to transfer charge between battery 3214 and energy storage elements electrically connected to system bus 3203, such as to balance the charge among batteries 3214 and / or help ensure that each battery 3214 reaches its minimum or maximum state of charge approximately simultaneously. For example... Figure 33 This is a diagram illustrating an example of charge transfer in an embodiment of the energy storage system 3200, where N equals 4, i.e., where the stack 3202 includes four BMS nodes 3208. Figure 33This includes the logically represented boxes for each BMS node 3208, and the vertical lines logically representing the system bus 3203. Figure 33 In the case of overcharging, battery 3214(1) of BMS node 3208, and controller 3206 accordingly controls transfer switches 3224(1) and 3226(1) so that transformer 3228(1) transfers X coulombs from BMS node 3208(1) to system bus 3202. On the other hand, batteries 3214(3) and 3214(4) of BMS nodes 3208(3) and 3208(4) are undercharged. Controller 3206 accordingly controls transfer switches 3224(3) and 3226(3) so that transformer 3228(3) transfers Y coulombs from energy storage bus 3203 to BMS node 3208(3). In addition, controller 3206 controls transfer switches 3224(4) and 3226(4) so ​​that transformer 3228(4) transfers Z coulombs from energy storage bus 3203 to BMS node 3208(4). exist Figure 33 The three charge transfer steps described can occur simultaneously, or they can occur at two or more different times. Additionally, although not strictly necessary, in some implementations, the charge transferred from BMS node 3208 to system bus 3203 is equal to the charge transferred from system bus 3203 to BMS node 3208, such that X coulombs = Y coulombs + Z coulombs.

[0414] Additionally, some embodiments of the energy storage system 3200 are configured to safely discharge the battery 3214, such as by transferring the charge of the battery 3214 to one or more other batteries 3214 in the stack 3202, and / or by transferring the charge of the battery 3214 to an energy storage element electrically connected to the system bus 3203, in response to the battery being identified as unsafe. For example, suppose the battery 3214(1) is identified as unsafe. Some embodiments of the energy storage system 3200 are configured to safely discharge the battery 3214(1) by transferring the charge of the battery 3214(1) to batteries 3214(3) and 3214(4), and / or to one or more other batteries 3214, such as by using the above-mentioned... Figure 33 The process discussed or a similar process.

[0415] Figure 34 This is an illustrative block diagram of an example energy storage system 3400, which is... Figure 32An alternative implementation of the energy storage system 3200 includes replacing the fuel cell stack 3202 of BMS node 3208 with a fuel cell stack 3402 of BMS node 3408. Furthermore, the energy storage system 3400 includes a power transfer bus 3430 for transferring charge between batteries 3214, as described below. The power transfer bus 3430 and the system bus 3203 optionally share a common negative node (-) (not shown). The difference between BMS node 3408 and BMS node 3208 is that, within each BMS node 3408, the secondary winding S and the secondary transfer switch 3226 are connected in series across the two ends of the power transfer bus 3430 (i.e., between the positive node (+) and the negative node (-) of the power transfer bus 3430), instead of connecting across the two ends of the system bus 3203. Each BMS node 3408 may optionally also include one or more of the following: (a) a capacitor 3432 electrically connected to both ends of the power transfer bus 3430, and (b) an overvoltage and undervoltage protection (OVP / UVP) circuit 3434. The capacitor 3432 provides energy storage on the power transfer bus 3430, and the OVP / UVP circuit 3434 helps prevent excessively high or low voltages on the power transfer bus 3430, as discussed below.

[0416] Energy storage system 3400 operates in the same manner as energy storage system 3200, except that transformer 3228 transfers charge between battery 3214 and power transfer bus 3430, instead of transferring charge between battery 3214 and system bus 3203. Therefore, Figure 33 The example scheme can be applied to the energy storage system 3400, but the system bus 3203 replaces it. Figure 33 The power transfer bus 3430 is included. Additionally, some embodiments of the energy storage system 3400 are configured to safely discharge the battery 3214, such as by transferring the charge of the battery 3214 to one or more other batteries 3214 in the stack 3202, and / or by transferring the charge of the battery 3214 to a capacitor 3432 electrically connected to the power transfer bus 3430, in response to the battery being identified as unsafe.

[0417] The voltage across the power transfer bus 3430 is equal to the voltage V across each secondary winding S. sThe voltage is affected by the action of BMS node 3408. Specifically, the transfer of charge from battery 3214 to power transfer bus 3430 increases the voltage on power transfer bus 3430, and the transfer of charge from power transfer bus 3430 to battery 3214 decreases the voltage on power transfer bus 3430. Therefore, the voltage on power transfer bus 3430 may rise to an excessively high value, or the voltage may drop to an excessively low value when a large amount of charge is transferred to or from power transfer bus 3430. Each instance of the optional OVP / UVP circuit 3434 helps prevent excessive voltage swings on power transfer bus 3430 by preventing its respective BMS node 3408 from driving the voltage on power transfer bus 3430 to be too high or too low. For example, suppose BMS node 3408(2) is transferring charge from battery 3214(2) to power transfer bus 3430, and the voltage on power transfer bus 3430 rises to a maximum threshold. The OVP / UVP circuit 3434(2) can cause the BMS node 3408(2) to stop transferring charge to the power transfer bus 3430 in response to this, to prevent the voltage on the power transfer bus 3430 from rising further. As another example, suppose the BMS node 3408(1) is transferring charge from the power transfer bus 3430 to the battery 3214(1), causing the voltage on the power transfer bus 3430 to drop to a minimum threshold. The OVP / UVP circuit 3434(1) can cause the BMS node 3408(1) to stop transferring charge from the power transfer bus 3430 in response to this, to prevent the voltage on the power transfer bus 3430 from dropping further.

[0418] Figure 35 This is an illustrative block diagram of an example energy storage system 3500. Energy storage system 3500 is... Figure 34 An alternative implementation of the energy storage system 3400 includes a fuel cell stack 3502 replacing the fuel cell stack 3402 of the BMS node 3408. Additionally, the energy storage system 3500 includes a battery 3532 electrically connected to the positive (+) and negative (-) terminals of the power transfer bus 3430. Except for omitting the capacitor 3432 and the OVP / UVP circuit 3434 from the BMS node 3508, Figure 35 BMS node 3508 and Figure 34 The BMS node 3408 is the same. Therefore, the energy storage system 3500 operates in the same manner as the energy storage system 3400, except that the energy storage system 3500 is configured such that the controller 3206 controls the operation of the transfer switches 3224 and 3226, so that the power conversion bus 3430 provides a voltage V. auxThe regulated auxiliary power rail. Additionally, some embodiments are configured to safely discharge battery 3214, such as by transferring the charge of battery 3214 to one or more other batteries 3214 in the stack 3202, and / or by transferring the charge of battery 3214 to battery 3532 electrically connected to the power transfer bus 3430, in response to the battery being identified as unsafe.

[0419] An auxiliary power rail is used, for example, to power one or more devices with voltage requirements different from those of the electrical load 3204, such as low-voltage devices in automotive applications. In some embodiments, V aux The voltage V across the electrical load 3204 is lower than the voltage V. L For example, in a particular implementation, V L For hundreds or even thousands of volts, while V aux Less than 100 volts (e.g., 12 volts, 18 volts, 24 volts, 48 ​​volts, etc.). In automotive applications of the energy storage system 3500, the battery 3532 is optionally an automotive battery.

[0420] The above description is provided to enable any person skilled in the art to create and use a safe battery energy management system, a safe battery management system node, and related methods. Various modifications to the embodiments will be apparent to those skilled in the art, and the general principles defined herein can be applied to other embodiments and applications without departing from the spirit and scope of the invention. In the foregoing description, numerous details have been set forth for purposes of explanation. However, those skilled in the art will recognize that embodiments of this disclosure can be practiced without using these specific details. In other instances, well-known processes are shown in block diagram form so as not to obscure the description of the invention with unnecessary detail. In different drawings, the same reference numerals may be used to denote different views of the same or similar components. Therefore, the above description and drawings based on examples of the invention are merely illustrative of the principles of the invention. It will be understood that those skilled in the art can make various modifications to the embodiments without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

1. A battery pack, comprising: Multiple batteries, connected in series; Multiple switches, the multiple switches including: Each isolation switch is used for each battery, and each isolation switch is configured to selectively isolate its respective battery from the other batteries in the battery pack. For each battery, a bypass switch is configured to selectively provide a path for current flowing through the battery pack to bypass its individual batteries; and The controller is configured to control the plurality of switches, enabling each battery to be individually connected to and disconnected from the power source / charger. The controller is further configured to enable the battery pack to operate in a safe mode by: (i) Dividing the plurality of batteries into a first subset and a second subset, such that the first subset of the plurality of batteries provides an output voltage not exceeding a predetermined safety value. (ii) closing the respective isolating switches for each battery in the first subset of the plurality of batteries, and opening the respective bypass switches for each battery in the first subset of the plurality of batteries, and (iii) causing the respective isolation switches for each battery in the second subset of the plurality of batteries to open, and causing the respective bypass switches for each battery in the second subset of the plurality of batteries to close.

2. The battery pack according to claim 1, wherein, The controller and the plurality of switches are configured to enable the battery pack to operate in a plurality of additional battery stack operating modes, including a normal charging mode, a normal discharging mode, and a bypass mode.

3. The battery pack according to claim 2, wherein, The additional fuel cell stack operating modes also include a float charge mode.

4. The battery pack according to claim 3, wherein, The controller is also configured to cause the battery pack to operate in one of the bypass mode, the float mode, and the safety mode in response to a fault in the energy storage system including the battery pack.

5. The battery pack according to claim 4, wherein, The faults are selected from the group consisting of stack-level series arcs, system-level series arcs, stack-level parallel arcs, system-level parallel arcs, and faults in the subsystems of the energy storage system.

6. The battery pack according to claim 1, wherein: The controller and the plurality of switches are configured to enable the battery pack to operate in a plurality of additional battery stack operating modes, including a normal charging mode, a normal discharging mode, and a float charging mode. as well as The controller is also configured to cause the battery pack to operate in the float charging mode in response to an arcing fault occurring in the energy storage system including the battery pack.

7. The battery pack of claim 1 further includes a respective DC-DC converter electrically connected to each battery.

8. The battery pack according to claim 7, wherein, Each DC-DC converter is configured to transfer charge between its individual cells and another cell in the battery pack.

9. The battery pack according to claim 7, wherein, Each DC-DC converter is configured to transfer charge between its individual batteries and the bus electrically connected to the battery pack.

10. The battery pack according to claim 9, wherein, Each DC-DC converter is electrically connected to the bus.

11. The battery pack according to claim 10, wherein, The bus electrically connects the battery pack to the electrical load.

12. The battery pack according to claim 10, wherein, The bus is a power transfer bus, which is configured to transfer charge between the plurality of batteries.

13. The battery pack according to claim 10, wherein, The controller is configured to control the DC-DC converter to regulate the voltage on the bus.

14. A battery pack, comprising: Multiple battery management system (BMS) nodes, each BMS node including: Battery, An isolating switch configured to selectively isolate the battery of the BMS node from the batteries of other BMS nodes; and A bypass switch configured to selectively provide a path for current flowing through the battery pack to bypass the batteries at the BMS node; and The controller is configured to control the isolation switch and bypass switch of each BMS node, so that the battery of each BMS node can be individually connected to and disconnected from the power source / charger. The battery series electrical connection of the BMS node, and The controller is also configured to enable the battery pack to operate in a safe mode by: (i) Divide the plurality of BMS nodes into a first subset of the plurality of BMS nodes and a second subset of the plurality of BMS nodes, such that the batteries of the first subset of the plurality of BMS nodes provide an output voltage not exceeding a predetermined safety value. (ii) closing the respective isolating switches for each BMS node in the first subset of the plurality of BMS nodes, and opening the respective bypass switches for each BMS node in the first subset of the plurality of BMS nodes, and (iii) Disconnect each isolation switch for each BMS node in the second subset of the plurality of BMS nodes, and close each bypass switch for each BMS node in the second subset of the plurality of BMS nodes.

15. The battery pack according to claim 14, wherein, The controller is also configured to control the isolating switch and the bypass switch of each BMS node, so that each BMS node can operate independently of each other BMS node of the battery pack in multiple operating modes, including normal charging mode, normal discharging mode and bypass mode.

16. The battery pack according to claim 15, wherein the plurality of operating modes further includes a float charging mode.

17. The battery pack according to claim 15, wherein, The controller is also configured to, in response to a battery insecurity in the first BMS node of the plurality of BMS nodes, cause the first BMS node of the plurality of BMS nodes to operate in its bypass mode.

18. The battery pack according to claim 17, wherein, The controller is also configured to discharge the battery of the first BMS node in response to the battery being unsafe.

19. The battery pack according to claim 17, wherein, The first BMS node further includes a discharge circuit configured to discharge the battery of the first BMS node, and the controller is further configured to discharge the battery of the first BMS node by activating the discharge circuit.

20. The battery pack according to claim 14, wherein, Each BMS node also includes a DC-DC converter electrically connected to the battery of the BMS node.

21. The battery pack according to claim 20, wherein, Each DC-DC converter is configured to transfer charge between the battery at its respective BMS node and the battery at at least one other BMS node of the battery pack.

22. The battery pack according to claim 20, wherein, Each DC-DC converter is configured to transfer charge between the batteries and buses at its respective BMS nodes.

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