CN117561665A - Battery control system and method - Google Patents

Abstract

A battery control system includes a plurality of battery cells that are individually controllable as units of a single cell or group of cells. Each controllable unit may be switchably activated or deactivated throughout the battery circuit, and one or more conditions of each controllable unit may be measured individually. Various techniques are disclosed for operating a battery control system to optimize or improve system performance and lifetime.

Description

Battery control system and method

Prior application

The present application claims priority from U.S. provisional application No.63/262,017 filed on 1 at 10 months of 2021 and U.S. provisional application No.63/183,980 filed on 4 months of 2021, the disclosures of both of which are incorporated by reference into the following detailed description.

Technical Field

The present disclosure relates generally to energy and to providing energy from a storage system, and more particularly to a Battery Control System (BCS), including its architecture, operating principles, and controller.

Background

Conventional fixed configuration battery architectures suffer from considerable limitations in battery management due to design limitations and lack of flexibility in the energy storage system. As the battery pack is repeatedly charged and discharged, individual cells (cells) may exhibit different characteristics-for example, some cells may charge or discharge faster than others. Monomers (cells) exhibiting unusual characteristics may overcharge or undercharge and continue to degrade faster than healthy monomers. The unusual properties of these unhealthy monomers can reduce the capacity and efficiency of the overall system and can cause damage to these monomers. For example, unhealthy cells may limit the overall battery operating cycle and may lead to more serious problems, such as extreme heat and even explosion due to the effects of a weak current Chi Nare runaway event.

Lithium iron phosphate (LFP) batteries tend to degrade in the ordinary cycle due to the formation of a Solid Electrolyte Interphase (SEI) layer in the negative electrode. The SEI is generated by electrochemical decomposition of the electrolyte, which competes with the faraday half-cell reaction required for the electrode surface, interfering with reversible lithium intercalation. Accordingly, the SEI layer increases the internal resistance of the battery, resulting in reduced charge/discharge efficiency, power loss, increased operating temperature, and shortened battery life.

Designers of battery-based power systems that utilize multiple cells are concerned with excessive exhaustion of the energy storage of the weaker battery and low energy conversion efficiency. Because of these challenges, techniques have been developed to manage charging and discharging to improve the capacity and efficiency of battery systems, such as active battery balancing. While some progress has been made in improving the operation of energy storage systems in response to the above-described problems, difficulties and complex challenges remain in controlling the storage and release of stored energy.

Disclosure of Invention

An aspect of the present disclosure relates to facilitating charging of different cells in the same string at different current levels, which in turn enables use of the cells in different states of charge (socs) and states of health (sohs). This capability is applicable to a variety of battery utilization and battery charging applications. One such application is battery-based energy storage systems for powering devices, homes, buildings, or other electrical consumers who traditionally draw power from an electrical grid. Other applications include energy storage for power generation facilities to provide increased capacity during peak hours or periods when renewable energy is not much available (e.g., during solar conditions, during night or dark/overcast conditions, during low wind or dangerous high wind periods in the case of wind). Other applications include battery powered or hybrid vehicles (e.g., highway, rail, marine, aeronautical) and thus carry batteries. In some related applications, an energy storage system utilizing at least some of the disclosed techniques may effectively utilize a secondary battery cell (second-life battery cell) whose previous service was terminated due to SoH. Some implementations may implement a comparable SoC between all batteries and minimize SoH degradation of these batteries, thereby extending their useful life. According to some embodiments, as described in detail below, batteries may be switched in and out based on their SoC or SoH. According to one aspect, all batteries are maintained at the same SOH so that the entire battery rack can be replaced at the same time.

A Battery Control System (BCS) according to one aspect is part of a memory system that is capable of controlling its charge and discharge current based on the SoC and SoH of each individual cell. The BCS may operate to maximize the service life of the battery, even secondary battery cells, before the battery is no longer available.

According to one aspect of an embodiment, a battery control system includes a first plurality of switching circuits, each of the switching circuits of the first plurality of switching circuits including a respective high-side switch, a respective low-side switch, and a respective battery cell, the high-side switch being selectively operable to couple a voltage of the respective battery cell into an accumulated voltage of the first plurality of switching circuits in an on setting of the high-side switch, and the respective low-side switch being selectively operable to omit a voltage of the respective battery cell in the accumulated voltage of the first plurality of switching circuits in an on setting of the low-side switch. The system also includes a first switch control circuit communicatively coupled to control respective settings of the respective high-side switch and the respective low-side switch of each of the switching circuits of the first plurality of switching circuits.

According to a related aspect, a method of operating a battery control system includes: receiving, by the battery control system controller, battery information for one or more battery cells from the multiplexing circuit; creating, by an optimization algorithm, a ranking order based at least in part on the virtual location of each cell in the serial string and the battery information; executing a grid current control algorithm based on the charge/discharge power set point and the grid voltage; outputting control signals to control the one or more battery cells to meet power/voltage requirements; comparing, by the switch control circuit, a control signal with all cell information to generate a switch setting for each of the one or more cells; the switch settings for each of the one or more battery cells are transmitted to the switch circuit.

In a related aspect, a battery control system includes: a plurality of battery cells arranged as a plurality of controllable units, wherein each controllable unit comprises at least one of the plurality of battery cells. A switching circuit is coupled to the plurality of battery cells and is arranged to facilitate individualized control of each of the controllable units, wherein the individualized control includes selectively activating/deactivating each controllable unit within an aggregate of battery cells. A sensing circuit is disposed at each controllable unit to measure a condition of at least one battery cell of the controllable unit. Further, a controller circuit is operably coupled to the switching circuit and the sensing circuit and is operable to read the sensing circuit and cause the switching circuit to dynamically activate and deactivate controllable units within an aggregate of battery cells based on the individualized control according to battery management instructions.

Causing the controller circuit, when executing the battery management instructions, to: estimating a state of each controllable unit based on a measured condition of at least one battery cell in the controllable unit, wherein the estimated state is indicative of a performance capability of the controllable unit; determining a hierarchy of the plurality of controllable units, the hierarchy being based on respective states of the controllable units; performing the individualized control based on the hierarchy level such that a respective position of each of the controllable units within the hierarchy level is used to set an activation duration of that controllable unit within the aggregate of battery cells; adjusting an order of the hierarchy in response to a change in the estimated state of one or more of the controllable units; and adjusting the order of the hierarchy in response to the operational history of one or more of the controllable units, regardless of any changes in the estimated states of those controllable units.

In another related aspect, an energy storage system includes a set of Battery Control Systems (BCSs), each BCS including a plurality of battery cells arranged as a plurality of controllable units, wherein each controllable unit includes at least one of the plurality of battery cells; a switching circuit coupled to the plurality of battery cells and arranged to facilitate individualized control of each of the controllable units. The individualized control includes selectively activating/deactivating each controllable element within the aggregate of battery cells. A sensing circuit is arranged at each controllable unit to measure a condition of at least one battery cell of the controllable unit; and a system controller operatively coupled to the switching circuit and the sensing circuit, the system controller being operable to estimate the energy storage level of each BCS in the group and to adjust the relative charge rate and the relative discharge rate of the battery cells between the group of BCSs based on the estimated energy levels.

A method for operating a battery control system according to another related aspect of the embodiment includes: measuring a condition of at least one cell of each controllable unit; estimating a state of each controllable unit based on a measured condition of at least one battery cell in the controllable unit, wherein the estimated state is indicative of a performance capability of the controllable unit; determining a hierarchy of the plurality of controllable units, the hierarchy being based on respective states of the controllable units; dynamically activating and deactivating each of the controllable units based on the hierarchy level such that a respective position of each of the controllable units within the hierarchy level is used to set an activation duration of that controllable unit; adjusting an order of the hierarchy in response to a change in the estimated state of one or more of the controllable units; and adjusting the order of the hierarchy in response to the operational history of one or more of the controllable units, regardless of any changes in the estimated states of those controllable units.

In another aspect, a method for operating an energy storage system is disclosed that includes providing a set of Battery Control Systems (BCSs), each BCS having a plurality of battery cells arranged as a plurality of controllable units, wherein each controllable unit includes at least one of the plurality of battery cells; performing an individualized control on each of the controllable units, wherein the individualized control includes selectively activating/deactivating each controllable unit within an aggregate of battery cells; measuring a condition of at least one cell of each controllable unit; estimating a storage level of each BCS in the group; and adjusting the relative charge rate and the relative discharge rate of the battery cells between the set of BCSs based on the estimated energy level.

Further aspects disclose one or more non-transitory machine-readable storage media containing instructions executable by a controller of an energy storage system to facilitate operation of a system in accordance with aspects described herein.

Drawings

In the drawings, like reference numerals identify like elements or acts. The dimensions and relative positioning of elements in the drawings are not necessarily drawn to scale. For example, the shapes of various elements and angles are not necessarily drawn to scale, and some of these elements may be arbitrarily enlarged and positioned to improve drawing legibility. Furthermore, the particular shapes of the elements as drawn, are not necessarily intended to convey any information regarding the actual shape of the particular elements, and have been solely selected for ease of recognition in the drawings.

Fig. 1A is a block diagram illustrating a system in which power is generated and stored in a plurality of battery cells in accordance with one or more embodiments.

Fig. 1B is a diagram illustrating an overall hardware architecture of a Battery Control System (BCS) as an example of the system of fig. 1 according to one type of embodiment.

Fig. 2 is a simplified schematic diagram illustrating a portion of a polarity inverter of the BCS of fig. 1B according to one example.

Fig. 3 is a block diagram illustrating a multiplexing circuit of the BCS of fig. 1B according to one example.

Fig. 4 is a simplified circuit diagram illustrating a portion of the multiplexing circuit of fig. 3 in more detail according to one example.

Fig. 5 is a system block diagram depicting a control signal arrangement of the BCS of fig. 1B, in accordance with one embodiment.

Fig. 6 is a diagram illustrating switching of individual battery cells into and out of a battery circuit according to an operation example of the BCS of fig. 1B, wherein an aggregated voltage of the battery circuit has a periodic waveform.

Fig. 7 is a related diagram showing switching of individual battery cells into and out of a battery circuit, wherein an aggregate voltage of the battery circuit is a time-varying direct current voltage, according to an operational example.

Fig. 8 is a process flow diagram illustrating operation of BCS150 of fig. 1B in accordance with some embodiments.

Fig. 9 is a diagram illustrating voltage waveforms at respective nodes of the BCS of fig. 1B according to an example use case.

Fig. 10A is a diagram illustrating superimposed voltage waveforms of grid inverter voltage and grid voltage according to an example.

Fig. 10B is a graph similar to fig. 10A showing superimposed voltage waveforms of a grid inverter voltage and a grid voltage, where the grid inverter voltage exceeds the grid voltage, resulting in the transfer of power from the battery cells to the grid, according to another example.

Fig. 11 is a block diagram showing an arrangement for connecting a variable dc battery system with an ac system, such as a power grid, according to various embodiments.

Fig. 12 is a flowchart illustrating an example algorithm that may be executed by the energy storage control system to adjust the state of charge (SoC) of an individual cell or group of cells.

FIG. 13 is a flow chart illustrating an example ordering algorithm that may be performed as part of the operation of the algorithm of FIG. 12.

Fig. 14 is a timing chart showing an example of operating the battery cell for different durations during generation of an alternating current wave.

Fig. 15 is a diagram showing an example of a battery cell dormancy algorithm that may be performed during a discharge state.

Fig. 16 is a block diagram showing an example arrangement of a plurality of BCSs aggregated in parallel with each other.

Fig. 17 is a flowchart illustrating a debugging process according to an example embodiment.

Detailed Description

In the following description, certain specific details are set forth in order to provide a thorough understanding of the various disclosed embodiments. One skilled in the relevant art will recognize, however, that an embodiment may be practiced without one or more of the specific details, or with other methods, components, materials, etc.

Reference throughout this specification to "one embodiment," "an implementation," "one aspect," or "one implementation" means that a particular feature, structure, or characteristic described in connection with the implementation is included in at least one implementation. Thus, the appearances of the phrases "in one implementation," "in an implementation," "in one aspect," "in an example," "in an embodiment," and the like in various places throughout this specification are not necessarily all referring to the same implementation. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more implementations.

Throughout the specification and the claims which follow, unless the context requires otherwise, the word "comprise" and the word "comprising" will be used in an inclusive or open-ended sense (i.e., not to exclude additional, unrecited elements or method acts).

As used throughout this specification and the appended claims, the singular forms "a", "an", and "the" include plural referents unless the content clearly dictates otherwise. It should also be noted that the term "or" is generally employed in its inclusive or meaning (i.e., "and/or") unless the context clearly and clearly states otherwise.

The headings and abstract of the disclosure are provided herein for convenience only and do not interpret the scope or meaning of the embodiments.

Overview of the System

Fig. 1A is a block diagram illustrating a system 100 in which power is generated and stored in a plurality of battery cells in accordance with one or more embodiments. The system 100 includes an energy capture device 102, a generator 104, a generator control system 106, an energy storage system 110, an energy storage control system 108, and a load 112.

The energy capture device 102 may be a mechanical energy source, such as a turbine or other rotating element that, as a result of rotation, provides mechanical energy to the generator 104 via corresponding rotation of the rotor or shaft. The generator 104 includes a stator that generates electrical power from mechanical energy received from the mechanical energy capture device 102. The operation of the mechanical energy capture device 102 and the generator 104 in connection therewith is described in U.S. patent No.8,878,373, which is incorporated herein by reference.

In a related embodiment, the energy capture device 102 and the generator 104 may be integrated as a singular system (singular system). For example, in some embodiments, the energy capture device 102 and the generator 104 may be a photovoltaic (i.e., solar) energy capture system that receives solar energy and produces an electrical power output.

As described in further detail, the generator 104 includes a plurality of solid state electronic modules operable to selectively output a power signal based on a power output of the generator 104.

Although the generator control system 106 and the energy system control system 108 are described and depicted as distinct control systems, the generator control system 106 and the energy system control system 108 may be part of a single control system in at least some embodiments that control the generator 104 and the energy storage system 110.

The generator control system 106 is communicatively and electrically coupled to the generator 104 to control the power output from the generator 104. Specifically, the generator control system 106 is electrically communicatively coupled to a controller of the solid state electronic modules of the generator 104 via an interface to control the output of the solid state electronic modules. In at least some embodiments, the generator control system 106 can interact with the solid state electronic module to change the topology of the solid state electronic module. Topology refers to the relative arrangement of the components of a solid state electronic module. Modifying the topology changes the current and voltage characteristics of the output power waveform generated by the solid state electronic module.

The energy storage system 110 includes a plurality of battery cells and a switch operable to selectively control the charging and discharging of the individual battery cells or the commonly controllable battery pack as individually controllable units. For simplicity, individual battery cells in this specification refer to individually controllable units (e.g., that can be switched into a larger battery circuit consisting of a combination of switchable units or bypassed). It should be understood that each reference herein to a "cell," "battery cell," or "single cell" refers to an individually controllable unit of one or more physical cells unless explicitly stated otherwise.

In some embodiments, a switch may be associated with each cell that is operable to selectively connect a cell with one or more terminals of other cells to organize the battery cell group into a desired topology for charging or discharging the cell. Using a switch, the cells may be selectively engaged with or disengaged from each other, with or from an input of the energy storage system 110, or with or from an output of the energy storage system 110. In some embodiments, the switches include one or more solid state switches, such as Metal Oxide Semiconductor Field Effect Transistors (MOSFETs), bipolar Junction Transistors (BJTs), insulated gate bipolar junction transistors (IGBTs), thyristors (e.g., silicon controlled rectifiers), diodes, triodes, and the like. In some embodiments, the switch may also include an electromechanical switch, such as a multi-throw switch, contactor, or relay switch.

The topology of a set of cells may be dynamically reconfigured to achieve a desired output voltage waveform or output current capacity based on the charge or discharge characteristics of the cells and the state of health of the cells.

The energy storage control system 108 may determine a status associated with each of the battery cells or with the battery cell stack. This state may indicate the charge capacity of the monomer, e.g., the rate at which the monomer is currently able to charge or the charge capacity of the monomer; or the discharge capacity of the monomer, such as the rate at which the monomer can be discharged or the capacity at which the monomer is discharged. In other examples, a state of health (SOH) measurement may be determined based on one or more markers. For example: internal resistance, capacity, nominal voltage at full charge, voltage under load (the voltage under load), rate of self-discharge, ability to accept charge, number of charge-discharge cycles of the cell, lifetime of the cell, temperature of the cell during last use, or total energy of charge and discharge. The energy storage system 110 may include one or more monitoring systems that monitor these or other properties or states of each of the battery cells to determine their performance or SOH over time. For example, additional monitoring conditions may include situations where individual cells have been overcharged or undercharged, or situations where a cell has experienced a potentially damaging condition, such as a temperature exceeding a recommended temperature range for the cell.

The monitoring system may be in communication with the energy storage control system 108, and the energy storage control system 108 may computationally determine information about the SoC, performance, or SoH of the battery cells and use the information about how to determine the topology of the battery cells for charging or discharging. For example, the energy storage control system 108 may store data related to the performance or health of the battery cells in the memory of the control system 108 and preferably charge or discharge certain cells having better performance or health characteristics. Some cells that exhibit a lower quality health or performance may be disconnected from other battery cells and marked for investigation, maintenance, or replacement. The monitoring system may be connected to a current, voltage, temperature or other sensor, to a battery cell or terminal thereof for determining performance or health information thereof. For example, the measured voltage at the terminals of the cell may be compared to the current flowing to and from the cell to determine the internal resistance of the cell, or the voltage may be compared to an expected voltage measurement to determine the SOH of the cell. In other examples, the usage indicia associated with each battery cell may be stored in non-volatile memory. The usage indicia may include one or more indicators, such as: a counter for a charge or discharge cycle, a counter for an over-temperature event that is incremented when the measured temperature of the cell exceeds a defined threshold, a counter for an over-current event that is incremented when the measured charge or discharge current exceeds a corresponding threshold, a timer for measuring the duration of the cell discharging below a defined threshold or in an overheat or over-current event, etc.

The energy storage system 110 may also include one or more power regulators that modify the characteristics of the power provided from the battery cells. For example, the one or more power regulators may convert Direct Current (DC) from a battery cell or battery cell stack into Alternating Current (AC) having a set of electrical characteristics determined based on load conditions associated with load 112. The electrical characteristics include current capacity, voltage level and frequency of the generated alternating current.

The system 100 may include a converter subsystem 114 that selectively provides power from the generator 104 or the energy storage system 110 to the load 112. The converter subsystem 114 may include a set of power converters capable of converting direct current provided from the energy storage system 110 to alternating current to be provided to the load 112. The converter subsystem 114 may also include a second set of converters to convert the power supplied from the generator 104 into a different form for provision to the load 112. The first and second sets of power converters of the converter subsystem 114 may operate in conjunction with each other to provide a desired output, e.g., the first set of power converters may convert direct current from the energy storage system 110 to alternating current having a desired set of electrical characteristics (e.g., frequency, current capacity, voltage level, phase), and the second set of power converters may convert alternating current or direct current from the generator 104 to alternating current having the same desired set of electrical characteristics. The power converter may include a set of electronic switching components as described in U.S. patent No.8,878,373.

The converter subsystem 114 may be controlled by a control system in communication with the energy storage control system 108 and the generator control system 106. The control system controlling the converter subsystem 114 may obtain information regarding the power demand of the load 112 or the expected power demand of the load 112 and interact with the energy storage control system 108 and the generator 104 to determine how to meet the power demand or the expected power demand. The control system controlling the converter subsystem 114 may be part of a control system including the generator control system 106 or the energy storage control system 108. In such embodiments, the larger control subsystem may be part of an integrated system that generates power, stores power (i.e., in the energy storage system 110), determines the power requirements of the load 112, and interacts with components of the system to optimize performance of the system.

Each control system 106, 108 (and any other control system or "controller" described herein) may include a digital controller including one or more processing devices (e.g., microprocessor cores), random access memory, non-volatile data memory, input/output circuitry, and system interconnect circuitry arranged according to a suitable architecture. The circuitry of the corresponding control system may be implemented as a microcontroller system, wherein these components are integrated as a single packaged Integrated Circuit (IC) or provided as a chipset. Notably, the nonvolatile data memory contains instructions executable by the microprocessor core that, when executed, transform the control circuitry into a dedicated controller implementing one or more control algorithms, portions of which are described below.

In a related embodiment, one or both of the control systems 106, 108 may be distributed across a plurality of devices, each having respective processor circuits and instructions that execute respective portions of the control system's algorithm. For example, consistent with some of the embodiments described below, the energy storage control system 108 may be implemented with a first portion executing on a processor of the polarity inverter 152 (fig. 1B), while other portions execute at each of the multiplexing circuits 204 (fig. 3-6).

Battery control system embodiments

Fig. 1B is a diagram showing an example of an overall hardware architecture of a Battery Control System (BCS) 150 according to an embodiment. BCS150 is an implementation of energy storage system 110, energy storage control system 108, and converter subsystem 114. According to one aspect, the BCS150 includes an energy storage system 110, which energy storage system 110 is capable of controlling the charging and discharging of each individual cell based on its SoC and SOH. Such control of the charging and discharging of each cell may maximize the life of each cell before it becomes no longer available. As an example, as described in more detail below, the BCS150 may implement an optimization algorithm to select which cells should be charged or discharged at a particular time or current level in order to balance the overall usage of the cells and maximize their individual lives.

BCS150 may be constructed as a single phase or multi-phase system. Each phase includes an inverter 152 and n battery racks 154, the inverter 152 being an embodiment of the converter subsystem 114, each rack containing m battery cells 156, such that the system contains a total of n x m battery cells. A controller or multiplexing control circuit may be provided on each rack to control cell switching operations and communicate with the inverter 152 via a suitable communication protocol. In addition, there may be additional controllers or inverter control circuitry as part of the inverter 152 that may provide overall coordination of the components of the BCS150 and provide an interface that may be accessed by an authorized user (e.g., a system administrator).

A cable harness system 158 provides electrical interconnection between all of the battery racks 154 and the inverter 152.

Fig. 2 is a simplified schematic diagram illustrating a portion of an inverter 152 according to an example. The inverter 152 may be used to transfer power from a power source to charge the battery cells 156 or to discharge the battery cells 156 to a load. The circuit includes a full H-bridge and full wave rectifier topology 202. The input or output of the circuit is connected to an energy source or load 200, 201, respectively. The energy source or load 200, 201 may be a grid that is capable of powering the BCS150 at one time and drawing power from the BCS150 through the filtering component 206 at another time. Terminals dcbus+ and DCBUS-are coupled to multiplexing circuit 204.

Each of the switching elements S1 to S4 may be implemented with one or more semiconductor switching devices of the type described above. The diodes D1 to D4 may be implemented as discrete components or they may be integrated into their respective switching elements S1 to S4.

The H-bridge arrangement of switching elements S1 to S4 is used to provide an alternating current from the unidirectional current output by the cells of the BCS 150.

Inverter 152 rectifies the negative grid voltage to a positive voltage for connection to battery cell 156 through multiplexing circuitry 204. In this function, the switching frequency may be twice the grid frequency, resulting in negligible switching losses, which are typically significant losses for conventional switch-mode inverters.

In the depicted example, the inverter 152 includes a battery system controller 208 (which is an implementation of the energy storage control system 108). As shown, the battery system controller 208 is arranged to control each of the switching elements S1 to S4. Additionally, the battery system controller 208 may be connected with the multiplexing circuit 204 to read sensed conditions and other battery cell information and command a switch of battery cells. To this end, the multiplexing circuitry 204 may include communication circuitry (e.g., a microcontroller including a Universal Asynchronous Receiver Transmitter (UART), amplification/line driver circuitry) to implement the physical layer and protocol stack as appropriate.

Inverter 152 may also regulate or provide charging or load current. In some embodiments, the battery cells are charged or discharged according to set points provided by an external controller as discussed below.

The multiplexing circuit 204 comprises separate circuits, which may be arranged according to an example, as shown in fig. 3. Each of the individual multiplexing circuits 1, 2,..n controls one or more battery cells. Fig. 4 shows a multiplexing circuit according to an example in more detail. Each cell is a half-bridge voltage source that can be connected to or disconnected from the entire circuit by switching on one of the two switching devices SL, SH. For example, when the high-side device SH is turned on, the battery cell is connected to the serial output voltage. When the low-side device SL is switched on, the monomer will be bypassed. According to some embodiments, the two switching devices SL, SH operate complementarily with dead time. Dead time may be provided such that both devices are turned off to avoid current breakdown damaging the switching device and possibly affecting the battery cell. The control signaling for each switching device SL, SH may be provided by the battery system controller 208 (or other implementation of the energy storage control system 108).

As in the example shown in fig. 4, each multiplexing circuit uses two switches, a high side switch SHn and a low side switch SLn, switching its corresponding cell 1, 2, …, M (collectively referred to as cell n) into and out of the overall circuit. For each monomer n, SHn or SLn is in an on state at any given time. When SHn is on and SLn is off, monomer n is in the circuit. Alternatively, monomer n is bypassed when SHn is off and SLn is on. When each switch SHn, SLn is switched to be included in or omitted from the aggregation circuit, the total output voltage Vout varies. As the multiplexer rate changes, the output frequency also changes.

The multiplexing circuit comprises one or more sensors sen_1, sen_2, …, sen_m arranged to monitor one or more of the cell voltage, cell current and cell temperature. The monitored conditions measured by the sensors are provided to the battery system controller 208 (or other controller implementing the energy storage control system 108). If any of the cells is experiencing an overheat, overvoltage or overcurrent condition, the cell may be switched out of the circuit by the controller 108, 208. In addition, such measurements may be used to evaluate SOH of the battery cells. Thus, global protection is provided for each monomer. For example, if a monomer encounters an overheat condition, the monomer may be disconnected until it cools down and then the entire circuit may not be reintroduced. In various embodiments, the sleep period is based at least in part on the voltage, current, or temperature of the cell. Thus, the impedance of a given cell decreases and the lifetime of a given cell increases.

Thus, the multiplexing circuit 204 has three main functions: switching to add or remove individually controllable battery cells from the battery circuit, communicating to send sensed measurements and receive control signals from the energy storage control system 108, and providing local protection for each cell in a manner similar to that described above in connection with monitoring conditions that are communicated to the battery system controller 208, but the local protection can be implemented directly in the multiplexing circuit 204 without requiring communication between components. Fig. 5 is a system block diagram depicting a control signal arrangement according to one embodiment. An example of a communication arrangement between the multiplexing circuit (MUX) 204, the battery system controller 208 and the demand controller 500 is shown. Each multiplexing circuit 204 communicates with the battery system controller 208 to receive the battery cell switch command from the demand controller 500. In some embodiments, battery cell information or overall battery system performance, soC, soH, or other power availability or capacity information (which is derived from common battery cell information for all monitored battery cells) may be provided to demand controller 500. Demand controller 500 may be a controller associated with a load, a grid, a control center, or other system utilizing BCS 150.

A user of the demand controller 500 (which may be, for example, a grid operator) issues commands and receives feedback from the battery system controller 208. The battery system controller 208 communicates with the multiplexing circuitry 204 and implements a control algorithm to coordinate the operation 204 of the multiplexing circuitry.

According to one type of embodiment, the battery system controller 208 sends a message to the multiplexing circuitry 204 via a first type of communication interface (e.g., one or more serial buses 504, 506). The message sent to multiplexing circuitry 204 includes a battery switch command. The battery system controller 208 receives messages from the multiplexing circuitry 204 via a first type of communication interface or via a second type of communication interface, such as a Controller Area Network (CAN) bus 502, 504. The messages sent from multiplexing circuitry 204 may include battery voltage, current, temperature measurements, soC, soH, charge or discharge status, etc. The first type or the second type of communication interface may be implemented as FLEXRAY, I ² C. Universal Serial Bus (USB), an interface according to any one of the IEEE 1394 series of standards, an IEEE 802.3 (ethernet) local area network, a Fibre Channel (FC), a wireless network interface according to the IEEE 802.11 series (WiFi) or IEEE 802.15 series (WPAN/bluetooth) standards, or any other suitable method of communication.

Fig. 6 is a diagram showing that respective battery cells are switched into and out of a battery circuit according to an operation example. The voltages of the individual cells are summed by the series connection of multiplexing circuits 204. With a timing switch, each cell: monomer 1, monomer 2, monomer 3, …, monomer mxn are activated or bypassed at different times and for different durations to create a specific waveform. The illustrated example of a waveform as indicated at 602 is a voltage waveform similar to a triangular waveform. In a related embodiment, the voltage waveform is shaped in this manner to resemble a sinusoidal waveform, a square waveform, or other shape.

In a related embodiment, the battery cell: monomer 1, monomer 2, monomer 3, …, monomer mxn can be switched to generate a time-varying dc voltage. Fig. 7 is a diagram showing an example of such a time-varying direct-current voltage. In this example, a group of battery cells is switched to an on state to generate a first direct voltage 704. The dc voltage may be adjusted according to the requirements of a controller, such as controller 208. For example, additional monomers may be activated to generate a greater dc voltage 706. Subsequently, some of the activated cells may be bypassed to reduce the dc voltage to voltage 708. This example shows that the activation of the battery cells is not necessarily according to a predefined waveform with periodicity. Instead, the dc voltage may be maintained in a steady state or may be adjusted according to the requirements of the operational protocol of the BCS implemented by the controller.

Fig. 8 is a process flow diagram illustrating the operation of BCS150 in accordance with some embodiments. At 802, the multiplexing circuits 204 collect battery cell information (e.g., voltage, current, temperature, or any other measurable quantity of the SoC that indicates SOH) using their respective sensors. The multiplexing circuit 204 transmits the battery cell information, which may reside partially or fully at the multiplexing circuit 204, the inverter 152, the control center, or the system of the grid operator, to the battery system controller 208.

At 804, the battery system controller 208 implements a virtual ordering of the cell voltages based on the virtual position of each cell in the serial string defined by the optimization algorithm output. Fig. 6 depicts one example of virtual ordering of batteries in a serial string, wherein virtual locations are represented by reference numerals bat_1 to bat_77.

At 806, the battery system controller 208 executes a control algorithm based on the charge/discharge power set point and, where applicable, the grid voltage. A control signal is output to control the battery cells to meet the power/voltage demand at the load. At 808, the battery system controller 208 compares the control signal to all cell voltages to generate switching settings for each cell, and then transmits these settings to the multiplexing circuit.

Fig. 9 is a diagram showing voltage waveforms at various nodes of BCS150 during an example use case. In this example, the use case is a battery charging mechanism. As shown, the grid voltage 902 is an ac voltage having a sinusoidal waveform.

The grid voltage 902 is generally tracked by switching cells into and out of a larger battery circuit by the multiplexing circuit 204 to produce a grid-tied voltage. The addition and removal of cells from the series combination produces a stepped voltage waveform as shown. At any time, when the total voltage of the series combination of cells that produce the grid-tied voltage 904 is lower than the grid voltage 902, a charging current flows from the grid to the cells. The magnitude of the charging current can be controlled by adjusting the combined voltage of the battery cells.

The multiplexed voltage 906 is shown as a rectified waveform as seen by a combination of battery cells. Notably, certain individual cells may be selectively connected to or bypassed by the charging current by switching the cells via respective multiplexing circuits.

Fig. 10A is a diagram showing overlapping voltage waveforms of the grid inverter voltage and the grid voltage. As shown, the stepped grid inverter voltage waveform has a smaller magnitude than the grid voltage, indicating that BCS150 is operating in its state of charge. Fig. 10B is a similar graph showing overlapping voltage waveforms of grid inverter voltage and grid voltage, where the grid inverter voltage exceeds the grid voltage, resulting in the transfer of power from the battery cells to the grid, consistent with BCS150 operating in its discharged (powered) state.

In some embodiments, the battery cells and inverter 152 are switched at a low frequency (e.g., twice the grid frequency). Such low switching frequency minimizes switching losses of the battery cells and the inverter switching devices. By a sufficient number of cells, the multiplexed battery system is able to produce a voltage very close to the grid voltage of a sinusoidal waveform, that is to say with low harmonic distortion and minimal harmonic content from the switching itself, so that the inverter output filter is minimized, reducing cost and size. Furthermore, because different cells in the same string experience different on-durations during half cycles of the grid voltage, the cells may be selected such that they charge at different average current levels.

In a related embodiment, the cells are used to generate a time-varying dc voltage, where the cells are switched primarily to adjust the polymerization voltage as needed and balance the cell utilization (aging). Such an embodiment can further reduce the switching amount and associated switching losses. The dc system may be used with an ac grid voltage using an inverter circuit. The appropriate inverter may generate an appropriate waveform synchronized with the grid voltage waveform.

Fig. 11 is a block diagram showing an arrangement for connecting a variable dc battery system with an ac system, such as a power grid, according to various embodiments. As shown, a switching battery system 1102 with multiplexing circuitry generates a variable dc voltage 1112. The inverter 1104 includes a voltage waveform generation circuit, such as a Pulse Width Modulator (PWM). The nominal dc voltage is provided as an input to inverter 1104 by switching battery system 1102. In turn, inverter 1104 converts the variable DC voltage into an AC waveform 1114 that is synchronized with grid 1106. In a related embodiment, the arrangement may operate in a forward or reverse order, with power flowing from the switching battery system 1102 to the grid 1106, or from the grid 1106 to the switching battery system 1102.

In variations of the arrangement of fig. 11, control of the power flow, either in the forward direction or in the reverse direction, may be regulated using the aggregate voltage of the switching battery system 1102, the inverter 1104, or by a combination thereof. In one arrangement, the PWM of inverter 1104 may be simply controlled to track the ac voltage of grid 1106 and not regulate the amplitude of ac waveform 1114 relative to the voltage of grid 1106. Instead, the switching battery system 1102 creates the appropriate series or series-parallel cell combination that can provide the appropriate dc voltage level for inverter operation in addition to optimizing the additional power source connected to the dc bus. In another embodiment, inverter 1104 may be operated to regulate the generated ac waveform 1114 to control the amount of power flow. In yet another related embodiment, both the switching battery system 1102 and the inverter 1104 may be operated to control the direction of power flow and also control the amount of power flow.

Thus, the disclosed systems and methods may be used with battery cells at different socs and sohs, and these battery cells may be rotated to rebalance the overall utilization of the cells. In some embodiments, the disclosed systems and methods may be used in energy storage systems that use secondary battery cells (second-life battery cell) that have been retired (retired) from their original service due to relatively low SoH.

According to one aspect, advanced optimization algorithms are utilized to select which cells are charged and discharged at which current levels to maximize the life of their individual or entire strings. The algorithm may be based on a battery aging model that includes SOC and SOH estimates. Depending on the number of cells and the complexity of the algorithm, this may be implemented in the microcontroller or inverter control circuit of the inverter, another computer, a central controller or by calculation based on big data.

Cell ordering

Related aspects of the present disclosure relate to controlling individual cells (or groups of individually controllable cells) of a BCS to achieve a desired current profile by prioritizing and scheduling placement of these cells in a circuit. Advantageously, in some cases, well-controlled charge and discharge current profiles can be used to mitigate SEI formation. For example, using a pulse current having a sleep time, or using a reverse current when charging or discharging a battery cell, may help to reduce polarization and thickness of the SEI layer.

In some embodiments, a status flag (e.g., soC, soH) for each of the battery cells is maintained in a data structure by the energy storage control system 108 or the battery system controller 208. The data structures may be organized and stored as a table, array, ordered list, database, or other suitable data structure.

Notably, the battery cells may be marked, grouped, or ordered in a data structure according to their respective status markers (e.g., socs). Fig. 12 is a flowchart illustrating an example algorithm that may be executed by the energy storage control system 108 (e.g., the battery system controller 208) to adjust the SoC. The algorithm may be performed for each monomer. As shown, information for a monomer is measured at 1202. In one example, the measurement may be performed by local sensing as part of multiplexing circuitry 204, as described above with reference to fig. 4. The measurement may include voltage or temperature sensing.

At 1204, any out-of-range conditions are determined. For example, under-or over-voltage conditions, overheating conditions, etc., wherein the measured quantity is compared with an upper range threshold and, where appropriate, with a lower range threshold. According to various embodiments, if an out-of-range condition is found for a given monomer, that monomer may be omitted from the SoC evaluation and may be marked as dormant, further evaluated, or disabled (decommissioning).

Decision 1206 determines whether the monomer is in a charged or discharged state. In the case where the monomer is charging, the process branches to 1208, where the SoC value of the monomer is incremented. In the case where the battery cell is discharging, the SoC of the cell is decremented at 1210. At 1212, a ranking order of the cells may be determined based on the resulting SoC values of the cell relative to the respective socs of other cells in the battery system.

FIG. 13 is a flow chart illustrating an example ranking algorithm that may be performed as part of operation 1208. The ordering algorithm uses index I to iterate the data structure of the battery cells to place the cells in order according to their SoC. As shown, the process begins at decision 1302 with a check whether the SORT_CHANGE flag is set to 1 (meaning that the ordering process is not complete, i.e., is in progress). In the affirmative case, the process continues to 1304, where the SORT_CHANGE flag is set to 0 and the index I is reset to 0.

Next, at decision 1306, it is determined whether index I is already at a maximum in the operational monomers. In the affirmative case, the process loops back to 1302. In the negative case (meaning index I is not at its maximum), the process continues to decision 1308, which tests whether the SoC of the cell in question is greater than the SoC of the next higher index cell. In the negative case, the monomers are not required to be reordered in order of the ordering of the data structures, and the process iterates from decision 1306. In the case where a monomer has a larger SoC than the next highest indexed monomer in the ordering, the process proceeds to 1310, which swaps the two compared monomers. Further, the corresponding index values are exchanged, and the SORT_CHANGE flag is set to 1. The process then begins iterating from decision 1306.

Once the ranking order is updated, the cells can be more easily managed to balance their utilization. In one example, when BCS150 is operating in its discharged state, battery cells having a relatively higher SoC than other cells are placed in the circuit for a longer duration than those other cells having a lower SoC. The battery voltage is turned on/off by comparison with the current controller output according to its position in the sequencing order.

Fig. 14 is a timing chart showing an example of operating the battery cell for different durations during generation of an alternating current wave. As shown in this simplified example, there are a plurality of battery cells, cell 1, cell 2, cell 3, and cell 50. The cells are arranged in series according to the topology of fig. 4 and can be individually switched to charge the entire battery (on setting) or bypassed (off setting). Thus, the voltages of the turned-on cells are added to produce the total output of the BCS. The cells are sequentially turned on and off to produce a stepped voltage waveform substantially resembling an ideal sine wave, which is the target output, similar to the technique described above with reference to fig. 6.

In this example, the battery cells are selectively switched such that the cell having the larger SoC value is on for a longer duration. For example, assume that monomer 3 has the largest SoC, then monomer 1, then monomer 2, and so on, up to monomer 50 (in other words, soC [ monomer 3] > SoC [ monomer 1] > SoC [ monomer 2] > … > SoC [ monomer 50 ]). Thus, monomer 3 is turned on at time t1 and turned off at time t 6; monomer 1 is turned on at time t2 and turned off at time t 5; monomer 2 is turned on at time t3 and turned off at time t 4. The cell 50 in this example need not achieve the target output and remains off for the entire duration of the power output.

The right side of the figure depicts the current waveforms through each of cell 3, cell 1, cell 2, and cell 50. The cell 3 is in the on setting for the longest duration of t1 to t6, providing more energy than the other cells. Likewise, monomer 1 provides more energy than monomer 2. Thus, a monomer with a higher SoC will lower its respective SoC faster than other monomers; thus, the system will eventually reach an balanced SoC state between the monomers.

Further, in this example, the monomer is given a sleep period. For monomer 1, the sleep cycle is at times t1 to t2 and times t5 to t6. For monomer 2, the sleep cycle is at times t1 to t3 and times t4 to t6. The monomer 50 has a sleep period throughout the half cycle. The cells (including cell 3) may additionally have a short sleep period between half-cycles of the output (i.e., between time t1 of the current half-cycle and time t6 of the previous half-cycle).

Sleep periods are typically short (in the millisecond range) and insufficient to provide monomer recovery; however, the sleep period still has the advantage of mitigating monomer heating due to continuous current. This advantage becomes even more important as SoC levels approach 0% or 100% where internal resistance tends to increase and cause self-heating temperatures of the monomers to rise.

In a related aspect, to accommodate the worst case scenario of cell discharge to 100% depth of discharge, there may also be many unusable "dead" cells, with the BCS designed to achieve the required peak output voltage using a fraction of the total number of cells. In some embodiments, a cell that is not used to generate the current output voltage (i.e., a sleep cell) is allowed to remain in its off setting for several half cycles (or longer). For example, to reach a peak voltage of 168V (for 120V ac systems), 65 cells are required in the series circuit, considering that the specific minimum operating voltage of the cells is 2.6V. In a particular system designed with 72 monomers, at least 7 monomers can sleep at a given time.

These monomers can choose to sleep according to the respective state (SoC, soH, temperature, historical usage-charge/discharge cycles, etc., or some combination of conditions), and sleep duration can be arranged for seconds, minutes, or hours. For some battery cell combinations, an extended sleep time can have a significant impact on improving the overall service life of the battery.

As described above, in some embodiments, the sleep time of a particular monomer is selected based on its location in the ordering data structure. Fig. 15 is a diagram illustrating an example of a monomer sleep algorithm that may be performed by the energy storage control system 108 or the battery system controller 208 during a discharge state. Fig. 15 depicts portions of a monomer ordering data structure for various states during three cycles of operations P1, P2, and P3 as described above with reference to fig. 13-14, according to an example embodiment. The periods P1 to P3 do not have to be aligned with the period of the alternating current waveform generated by the polarity inverter 152. Each cycle may include multiple cycles of the ac waveform and may begin or end at zero crossings of the ac waveform or other points along the ac waveform.

In this example, monomer 1 has the highest SoC and monomer 72 has the lowest SoC, ordered by SoC. According to one embodiment of the monomer modulation scheme, during period P1, monomers 1 through 67 are used to power in their discharged state, while monomers 68 through 72 are placed in a dormant state to be inactive. Of the cells 1 to 67, the cells 1 to 5 are assigned the on setting having the longest duration when generating the output power waveform, while the other cells 6 to 67 are assigned the correspondingly shorter on setting, similar to the technique described in the example above with reference to fig. 14. In this example, higher order cells correspond to shorter on-durations. Sleep cells 68-72 are completely bypassed (i.e., no current is discharged from these cells). For example, the duration of period P1 may be about minutes.

In period P2, the high SoC monomers 1 to 5 that have experienced a long on-duration are placed in sleep mode (e.g., as they are reordered to the top of the ordered data structure), regardless of their SoC level. Monomers 1 to 5 for dormancy may be selected according to a cell-dormancy standard (cell-dormancy criterion). The monomer dormancy criteria may be defined in terms of minimum duty cycle, number of monomers M at the bottom of the ordering order, temperature rise over the monitoring period, or other criteria corresponding to a particular use intensity. Monomers 68 through 72 may move down (but still near the top) in the ordering data structure so that these low SoC monomers may now be contained in active (non-sleep) monomers, but will discharge in a short time to minimize the drop in their socs. The remaining cells are also moved downward in the sequencing data structure such that they are switched on for a shorter or longer duration commensurate with their position in the sequencing order. In this example, the monomers 6 to 8 are high SoC monomers, relative to other active monomers, and are assigned to the on setting of the longest duration. For example, the duration of period P2 may be about a few minutes.

In period P3, high SoC monomers 1 to 5, which are always in a sleep state during period P2, are placed at the bottom of the ordering data structure to be allocated again to the high duration discharge. Monomers 6 to 8 that have been used for high duration discharge are placed at the top of the sequencing order, as shown in the dormant state. The low SoC monomers 71-72 may also be dormant to preserve their SoC, provided that they do not need to provide voltage for output power generation. The remaining cells 9 to 70 will be switched on for a shorter or longer duration depending on their position in the sorting order. This example shows that different amounts of monomer can be assigned to maximum duration discharge operations for different periods. Also, different amounts of monomer may sleep for different periods of time.

In a related embodiment, the ordering order of the monomers in the data structure may be adjusted between cycles based on the change in SoC of each of the monomers when the monomers are used. For example, if the SoC of cell 1 is no longer in the largest SoC group, then the physical cell may be reassigned with a different index number and placed in order appropriately so that another cell with a higher SoC is discharged for the longest duration.

In another related embodiment, one or more monomer conditions other than SoC may be considered in the ordering order. Such as SoH, operation history (charge/discharge cycle), battery temperature, etc. Current sharing between parallel BCS modules

In large-scale energy storage systems, multiple BCSs are typically aggregated in parallel with each other. Fig. 16 shows one such arrangement, where a plurality of BCSs, 150A, 150B, …, 150N (collectively BCSs 150) are connected in parallel to a load 600 via a power line 1602, the load 600 may be a power grid. The system controller 1604 executes instructions to read the status and condition of each of the BCSs 150, communicates with a controller of the load 600, which may be an Energy Management System (EMS), including reading power requirements from the EMS, and issues commands to each BCS150 to coordinate the overall operation of the BCS.

In each BCS150, different battery cells may have different sohs. Furthermore, at any given moment, the battery cells in BCS150 can have different socs. Thus, the total energy storage capacity of each BCS150 may be different. In accordance with another aspect of the present disclosure, the system controller 1604 executes a multi-level optimization algorithm to maximize or at least increase the useful life of all of the cells in each of the BCSs 150.

At the system level, the current sharing technique between parallel BCSs is controlled based on the energy stored in each BCS 150. The amount of energy is estimated by each BCS150 and may be based on its individual SoC and optionally on additional status markers (e.g., soH or others). The system controller 1604 uses these values to calculate the charge/discharge current level for each BCS150 while ensuring that the entire system of BCSs is able to meet the power requirements of the load 600, as provided by the EMS. In case of a fault detected in one or some BCS units, e.g. they are out of service, the remaining BCS units may share the power demand without interrupting the operation of the system.

The following equation is an example of how the total energy stored in BCS150 is calculated based on the original capacity C of each of the SoC, soH, and monomers.

Wherein SoC and SoH are each values between 0 and 1, each representing a discount rate from an ideal corresponding condition, and capacity C is in units of energy.

In some embodiments, the power sharing between parallel BCSs 150 can be calculated by, but is not limited to, the following equation:

the power discharged from the BCS150 is proportional to its stored energy, i.e., the higher the energy stored in the BCS150, the higher the power level of the discharge:

While the power charged from the BCS system is inversely proportional to its stored energy, i.e., the stored energy is higher and the BCS150 is charged at a lower power level.

P ₁ E ₁ ＝P ₂ E ₂ ＝…＝P _m E _m

Furthermore, the total discharge/charge power must satisfy the command from the EMS:

note that the above equation is presented for the simple case of the power sharing method. However, other relationships may be used in related embodiments. In some of these embodiments, the following principles are implemented:

BCSs with overall lower stored energy operate at lower charge/discharge currents than other BCSs to avoid rapid aging compared to other BCSs.

BCS with overall lower stored energy operate with lower discharge current and higher charge current to balance the overall system compared to other BCS.

Sometimes one of the BCSs can operate in the opposite current direction to the other parallel BCSs and the current level is very low (e.g. 1% to 2% of the rated current of the cell) to reduce polarization and further reduce the SEI layer. For example, after 100 cycles of ac charging, the BCS can discharge for several cycles while the other legs continue to charge.

Within each BCS150, the operation of all battery cells can be optimized or at least improved by controlling the operation based on certain battery state or condition information (e.g., soC, soH, and temperature). To minimize or at least reduce the effects of aging, and thus extend the life of the battery cell, one or a combination of the following techniques may be utilized in accordance with some embodiments:

A monomer sleep process is used, such as the examples described above with reference to 15 through 16. During monomer sleep, sleep is preferentially performed for a monomer having a low SoC and a monomer that has recently been operated in a discharge state for a relatively long on-duration.

The charge/discharge current level of each cell is calculated during a plurality of electrical cycles by a cell ordering algorithm based on its SoC and SoH. The cost function of each monomer is calculated based on its condition and then ordered in the data structure in the appropriate order. The battery system controller 208 uses this sequencing order to determine the on-time set for each cell within the electrical cycle, thereby controlling the pulse duration of the current through each cell. The following equation gives an example of a cost function for each monomer that takes into account SoC and temperature.

In the charging mode:

f _i ＝α×SoC _i +β×SoH _i +μ×g(t _i )

in discharge mode:

f _i ＝α×SoC _i +β×SoH _i -μ×g(t _i )

wherein f _i Is a cost function of monomer i;

α is the SoC coefficient;

beta is the SoH coefficient;

t _i is the temperature of monomer i;

μ is the temperature coefficient;

g(t _i ) Is a cost function of temperature and may be linear or non-linear depending on the particular cell characteristics.

f _i SoC [ i ] in the ordering algorithm described above with reference to fig. 13 to 14 may be replaced ]So that the temperature and SoH of each monomer are taken into account for ordering. Thus, all these factors are calculated to determine which monomers are exposed to higher currents.

When calculated by the battery system controller 208, these equations implement the following principles:

lower SoH and SoC monomers operate at lower average charge/discharge currents to reduce the aging rate of such monomers;

monomers with relatively lower socs, compared to other monomers, intentionally operate at lower discharge current and higher charge current to balance the socs of all monomers.

Monomers with a temperature higher than the other monomers are controlled to have a relatively longer sleep time (compared to other monomers in the BCS) to reduce their temperature and promote recovery of the monomer.

If both monomers have the same SoC and SoH, then the higher temperature monomer is controlled to charge and discharge using a relatively lower current than the charge or discharge current of the other monomers in the BCS.

Battery cell debugging

In a related aspect, the BCS implements a technique that allows a system operator to forego performing a test procedure of a secondary battery cell before incorporating the secondary battery cell into the BCS. This can provide economic and logistical benefits, such as saving the cost of operators to acquire and operate the test equipment and personnel, and speeding up the deployment time of the secondary battery cells. Thus, in some embodiments, BCS150 is programmed to perform an auto-debug process that determines the initial SoH and SoC of all battery cells at initial installation in the system and each time a cell is replaced.

Fig. 17 is a flowchart illustrating a debugging process according to an example embodiment. This process may be performed by the battery system controller 208 of the BCS 150. At 1702, new monomers are deployed in BCS150 and exposed to a common operating environment, where they are charged and discharged during operation. Each new monomer may be given a unique ID and its parameters may be tracked and recorded in a suitable data structure. The new monomer may mark its state as to be subject to debugging, or may place its ID in a debug data structure dedicated to the debugging process.

At 1704, BCS150 gathers baseline condition and operational mode information for those monomers and the environment prior to any significant operations of the new monomers under test for debugging. Examples of measured cell conditions include voltage (open loop or under load), current, cell temperature, and the like. Examples of the operation mode information include a charge or discharge mode and a duration of each mode. Examples of environmental conditions include ambient temperature outside of the monomer.

At 1706, the bcs150 collects status measurements and operational mode information for the new monomer during operation. These measurements may be made periodically according to a schedule, in response to a change in the manner of operation, or according to a combination. During normal operation under varying operating conditions (e.g., various load conditions, ambient temperature, etc.), use of these monomers to effect varying usage monitoring of their SoC over a sufficiently long duration generates data, such as SoH, for evaluating finer conditions of the monomers (not readily observable by direct electrical or thermal measurements). Notably, the BCS150 is able to measure open circuit voltage and battery voltage at different charge/discharge current levels by virtue of its multiplexing architecture as described above, which allows individual control or isolation of each cell.

At 1708, the measurements are used to calculate an internal model of the cell, which includes internal resistance, open circuit voltage, etc. The calculated values of the internal model parameters are then compared at 1710 to predefined empirical data obtained from various other cell experiments at different temperatures and SoC, soH levels. At 1712, the comparison results are applied to estimate the SoC and SoH of the monomer in question. The comparison of model parameter values and estimation of SoC and SoH may be performed using suitable algorithms, such as regression techniques, nearest neighbor classification, clustering, training neural networks (where empirical measurements are used as training data), and the like.

After the debug period, the new battery cells have their SoC and SoH values and can be classified and ordered according to the cell optimization strategy as described above.

Additional description and examples

Example 1 is a battery control system, comprising: a first plurality of switching circuits, each of the switching circuits of the first plurality of switching circuits including a respective high-side switch, a respective low-side switch, and a respective battery cell, the high-side switch selectively operable to couple a voltage of the respective battery cell into an accumulated voltage of the first plurality of switching circuits in an on setting of the high-side switch, and the respective low-side switch selectively operable to omit a voltage of the respective battery cell in the accumulated voltage of the first plurality of switching circuits in an on setting of the low-side switch; and a first switch control circuit communicatively coupled to control respective settings of respective high-side switches and respective low-side switches of each of the switching circuits of the first plurality of switching circuits.

In example 2, the subject matter of example 1 includes: wherein the respective high-side switch and the respective low-side switch of each of the switching circuits are electrically coupled in a half-bridge arrangement and operate in a complementary manner with one of the respective high-side switch and the respective low-side switch each in a respective on setting with dead time in which both the respective high-side switch and the respective low-side switch are in respective off settings prior to switching to the respective on setting of the respective high-side switch or the respective low-side switch.

In example 3, the subject matter of examples 1 to 2 includes: wherein the first plurality of m battery cells is arranged in the first rack; and further comprising: a number N of additional plurality of switching circuits, each of the switching circuits of the additional plurality of switching circuits including a respective high-side switch selectively operable to couple a voltage of a respective cell into the accumulated voltage of the first plurality of switching circuits in an on setting of the high-side switch, a respective low-side switch, and a respective cell, and the respective low-side switch selectively operable to omit a voltage of a respective cell of the accumulated voltage of the first plurality of switching circuits in an on setting of the low-side switch; a number N of additional switch control circuits communicatively coupled to control respective high-side switches and respective settings of respective low-side switches of each of the switch circuits of respective additional switch circuits of the additional plurality of switch circuits.

In example 4, the subject matter of example 3 includes: wherein the battery cells of each of the additional plurality of switching circuits are disposed on a respective one of a plurality of additional racks other than the first rack.

In example 5, the subject matter of example 4 includes a cable bundle electrically coupling battery cells of the first rack and the additional rack in series.

In example 6, the subject matter of examples 1 to 5 includes at least a first inverter comprising a plurality of switches electrically coupled in a full H-bridge topology, the first inverter having a set of input nodes electrically coupled to a power source and a set of output nodes electrically coupled to switching circuitry of at least the first plurality of switching circuitry; and a battery control system control circuit communicatively coupled with at least the first switch control circuit.

In example 7, the subject matter of example 6 includes: wherein the power source provides a plurality of phases of power via a power grid, the first inverter is a first power grid inverter coupled to a first phase of power provided via the power grid, and further comprising: a plurality of additional grid-tie inverters electrically coupling respective phases of power provided via the grid.

Example 8, the subject matter of examples 6 to 7 includes: wherein the battery control system control circuit controls the first inverter to rectify a negative voltage of the power supply to a positive voltage for connection with a battery cell of the switching circuit, wherein the first inverter operates at a switching frequency that is at least twice a waveform frequency provided by the power supply.

In example 9, the subject matter of examples 6 to 8 include: wherein the battery control system control circuit controls the first inverter to adjust the current provided by the power supply according to the setpoint to charge or discharge the battery cells, and then the battery control system control circuit sends a set of switching commands to the switching circuit.

In example 10, the subject matter of examples 6 to 9 includes: wherein the battery control system control circuit controls the first inverter according to an optimization algorithm to select which one or more battery cells should be charged or discharged at a current level so as to maximize the respective life of each of the battery cells.

In example 11, the subject matter of example 10 includes: wherein the battery control system control circuit implements a ranking order of the cell voltages based on the virtual positions of the cells in the serial string defined by the optimization algorithm output.

In example 12, the subject matter of examples 6 to 11 include: wherein each switching circuit includes a respective voltage sensor and a respective temperature sensor, and transmits battery information including a sensed voltage and a sensed temperature of the respective battery cell to the battery control system control circuit or a central controller.

In example 13, the subject matter of examples 6 to 12 include: wherein the battery control system control circuit executes a grid current control algorithm based on the charge/discharge power set point and the voltage provided by the power source to provide one or more control signals to at least the first switch control circuit.

In example 14, the subject matter of example 13 includes: wherein the battery control system control circuit compares the control signal with voltages of all battery cells to generate respective settings for the high side switch and the low side switch of the respective battery cell and transmits the generated settings to the respective switching circuit.

In example 15, the subject matter of examples 6 to 14 includes: wherein the charge and discharge current of each individual one of the battery cells is controlled based on the state of charge and the state of health of the respective battery cell.

In example 16, the subject matter of examples 4-15 includes a cable bundle that correctly matches the polarity of the battery cells to a set of inverter terminals.

In example 17, the subject matter of examples 1 to 16 includes: wherein the first switch control circuit controls timing of respective settings of respective high-side switches and respective low-side switches of each of the switch circuits of the first plurality of switch circuits to produce a stepped multiplexed output voltage resembling a positive portion of a sinusoidal waveform.

In example 17-2, the subject matter of examples 1 to 16 includes: wherein the first switch control circuit controls respective settings of respective high-side switches and respective low-side switches of each of the switching circuits of the first plurality of switches to generate a time-varying direct voltage.

Example 18 is a method of operating a battery control system, comprising: receiving, by a battery control system controller, battery information for one or more battery cells from a switching circuit; creating, by the switch control circuit, a ranking order based at least in part on the virtual location of each cell in the serial string and the battery information; executing, by the switch control circuit, a grid current control algorithm based on the charge/discharge power set point and the grid voltage; outputting control signals to control the one or more battery cells to meet power/voltage requirements; comparing, by the switch control circuit, the control signal with all of the cell information to generate a switch setting for each of the one or more cells; and transmitting the switch settings for each of the one or more battery cells to a switching circuit.

In example 19, the subject matter of example 18 includes: wherein the battery information is at least one of voltage and temperature.

In example 20, the subject matter of example 19 includes: wherein the battery information is provided by one or more sensors.

In example 21, the subject matter of examples 18 to 20 includes: wherein the ranking order is based at least in part on the optimization algorithm output.

Example 22 is a battery control system, comprising: a plurality of battery cells arranged as a plurality of controllable units, wherein each controllable unit comprises at least one of the plurality of battery cells; a switching circuit coupled to the plurality of battery cells and arranged to facilitate individualized control of each of the controllable units, wherein individualized control includes selectively activating/deactivating each controllable unit within the aggregate of battery cells; a sensing circuit disposed at each controllable unit to measure a condition of at least one battery cell of the controllable unit; a controller circuit operably coupled to the switching circuit and the sensing circuit, the controller circuit operable to read the sensing circuit and cause the switching circuit to dynamically activate and deactivate controllable units within the aggregate of battery cells based on individualized control according to battery management instructions; wherein the battery management instructions, when executed, cause the controller circuit to: estimating a state of each controllable unit based on a measured condition of at least one battery cell in the controllable unit, wherein the estimated state is indicative of a performance capability of the controllable unit; determining a hierarchy of the plurality of controllable units, the hierarchy being based on respective states of the controllable units; performing individualized control based on the hierarchy level such that a respective position of each of the controllable units within the hierarchy level is used to set an activation duration of the controllable unit within the set of battery cells; adjusting an order of the hierarchy in response to a change in the estimated state of one or more of the controllable units; and adjusting the order of the hierarchy in response to the operational history of one or more of the controllable units, regardless of any changes in the estimated states of those controllable units.

In example 23, the subject matter of example 22 includes: wherein the condition associated with each controllable unit measured by the sensing circuit includes a voltage of at least one cell of the controllable unit, a current through the at least one cell of the controllable unit, and a temperature of the at least one cell of the controllable unit.

In example 24, the subject matter of examples 22 to 23 include: wherein the state estimated by the controller circuit comprises a state of charge (SoC) value indicative of a degree of charge of at least one of the controllable units relative to its capacity.

In example 25, the subject matter of example 24 includes: wherein the state estimated by the controller circuit further comprises a state of health (SoH) value indicative of a degree of degradation of at least one cell of the controllable unit.

In example 26, the subject matter of example 25 includes: wherein the SoH value is determined based on at least one condition of the at least one monomer, the at least one condition selected from the group consisting of: internal resistance, capacity, nominal voltage at full charge, voltage under load, self-discharge rate, ability to accept charge, charge-discharge cycle number, lifetime, temperature of the at least one cell during last use, total energy of charge and discharge, or any combination thereof.

In example 27, the subject matter of examples 25 to 26 includes: wherein the hierarchy comprises an ordered set of respective identifiers representing controllable elements.

In example 28, the subject matter of examples 22 to 27 include: wherein at least a first portion of the hierarchy is ordered in the order of the values of the respective estimated states of the controllable elements.

In example 29, the subject matter of example 28 includes: wherein the battery management instructions, when executed, cause the controller circuit to determine the hierarchy such that controllable units having states indicative of estimates of relatively higher performance capabilities are assigned to relatively higher locations in a first portion of the hierarchy and controllable units having states indicative of estimates of relatively lower performance capabilities are assigned to relatively lower locations in the first portion of the hierarchy.

In example 30, the subject matter of example 29 includes: wherein the hierarchy level is further determined based on the current temperature of each controllable unit.

In example 31, the subject matter of example 30 includes: wherein the hierarchy is further determined based on a combination of an estimated state of charge (SoC) value, an estimated state of health (SoH) value, and a current temperature for each controllable unit, wherein the SoC value indicates a degree of charge of at least one cell of the controllable unit relative to its capacity, and wherein the SoH value indicates a degree of degradation of at least one cell of the controllable unit.

In example 32, the subject matter of examples 30 to 31 include: wherein, in the individualization control, when the battery cell is operated in a discharge state, the controllable unit allocated to a relatively higher position in the hierarchy is activated for a longer duration than the controllable unit allocated to a relatively lower position in the hierarchy.

In example 33, the subject matter of examples 30 to 32 includes: wherein, in the individualizing control, when the battery cells are operated in a charged state, the controllable units allocated to the relatively higher positions in the hierarchy are activated for a shorter duration than the controllable units allocated to the relatively lower positions in the hierarchy.

In example 34, the subject matter of examples 28 to 33 include: wherein the second portion of the hierarchy is ordered based on performance histories of certain ones of the controllable units.

In example 35, the subject matter of example 34 includes: wherein the second portion of the ordered set includes identifiers of certain controllable units that have undergone an activation duration according to a monomer dormancy criteria.

In example 36, the subject matter of examples 34 to 35 include: wherein in the individualised control the controllable units assigned to the second part of the hierarchy are not activated.

In example 37, the subject matter of examples 22 to 36 includes: wherein the switching circuit comprises controllable units arranged in series, and wherein in the individualised control the controllable units arranged in series are sequentially activated and deactivated to produce a varying voltage waveform.

In example 38, the subject matter of examples 22 to 37 includes: wherein in the individualized control, the controllable units are activated and deactivated in response to power demand information received from a controller associated with the load.

In example 39, the subject matter of examples 22 to 38 includes: wherein the battery management instructions, when executed, cause the controller circuit to perform a debugging process adapted for deploying a new controllable unit, wherein: the switching circuit exposes the new controllable unit to an operating environment in which the plurality of controllable units are exposed; baseline measurements of the condition of the new controllable element; after a defined operating period, additional measurements are made of the condition of the new controllable unit; the baseline measurements and the additional measurements are used to generate an internal model of the new controllable unit; comparing the internal model with an empirical reference model to produce a comparison; based on the comparison result, a discovery status of the new controllable unit is estimated, wherein the discovery status indicates a performance capability of the controllable unit.

In example 40, the subject matter of example 39 includes: wherein the defined operating period comprises changing an operating condition for a duration sufficient to effect a change in the discovery state.

In example 41, the subject matter of examples 39 to 40 includes: wherein the internal model represents parameters including internal resistance and open circuit voltage.

Example 42 is an energy storage system, comprising: a set of Battery Control Systems (BCSs), each BCS comprising: a plurality of battery cells arranged as a plurality of controllable units, wherein each controllable unit comprises at least one of the plurality of battery cells; a switching circuit coupled to the plurality of battery cells and arranged to facilitate individualized control of each of the controllable units, wherein individualized control includes selectively activating/deactivating each controllable unit within the aggregate of battery cells; a sensing circuit disposed at each controllable unit to measure a condition of at least one battery cell of the controllable unit; a system controller operably coupled to the switching circuit and the sensing circuit, the system controller operable to: estimating a storage level of each BCS in the group; the relative charge rate and the relative discharge rate of the battery cells in the set of BCSs are adjusted based on the estimated energy levels.

In example 43, the subject matter of example 42 includes: wherein the system controller is operable to adjust the relative charge rate and the relative discharge rate such that a first BCS of the group having a relatively lower energy storage level is controlled to charge and discharge at a relatively lower rate and a second BCS of the group having a relatively higher energy storage level is controlled to charge and discharge at a relatively higher rate.

In example 44, the subject matter of examples 42 to 43 includes: wherein the system controller is operable to adjust the relative charge rate and the relative discharge rate such that a first BCS of the group having a relatively low energy storage level is controlled to discharge at a relatively low rate and charge at a relatively high rate and a second BCS of the group having a relatively high energy storage level is controlled to discharge at a relatively high rate.

In example 45, the subject matter of examples 42 to 44 includes: wherein the system controller is operable to estimate the energy storage level of each BCS based on a set of a combination of an estimated state of charge (SoC) value, an estimated state of health (SoH) value, and a nominal capacity of each controllable unit within the BCS, wherein the SoC value indicates a degree of charge of the at least one cell of the controllable unit relative to its capacity, and wherein the SoH value indicates a degree of degradation of the at least one cell of the controllable unit.

In example 46, the subject matter of examples 42 to 45 include: wherein the system controller is operable to cause the set of BCSs to operate in a charged state or a discharged state and also to cause at least one BCS of the set to operate simultaneously with the operation of the other BCSs of the set, sometimes in a different state than the other BCSs of the set.

Example 47 is a method for operating a battery control system having a plurality of battery cells arranged as a plurality of controllable units, each controllable unit including at least one of the plurality of battery cells, the method comprising: measuring a condition of at least one cell of each controllable unit; estimating a state of each controllable unit based on a measured condition of at least one battery cell in the controllable unit, wherein the estimated state is indicative of a performance capability of the controllable unit; determining a hierarchy of the plurality of controllable units, the hierarchy being based on respective states of the controllable units; dynamically activating and deactivating individual ones of the controllable units based on the hierarchy level such that a respective location of each of the controllable units within the hierarchy level is used to set an activation duration of the controllable unit; adjusting an order of the hierarchy in response to a change in the estimated state of one or more of the controllable units; and adjusting the order of the hierarchy in response to the operational history of one or more of the controllable units, regardless of any changes in the estimated states of those controllable units.

In example 48, the subject matter of example 47 includes: wherein measuring the condition of at least one cell of each controllable unit includes measuring a voltage of the at least one cell, a current through the at least one cell, and a temperature of the at least one cell.

In example 49, the subject matter of examples 47 to 48 include: wherein estimating the state of each controllable unit comprises estimating a state of charge (SoC) value indicative of a degree of charge of the at least one cell of each controllable unit relative to its capacity.

In example 50, the subject matter of example 49 includes: wherein estimating the state of each controllable unit further comprises estimating a state of health (SoH) value indicative of the degree of degradation of the at least one monomer of each controllable unit.

In example 51, the subject matter of example 50 includes: wherein the SoH value is determined based on at least one condition of the at least one monomer, the at least one condition selected from the group consisting of: internal resistance, capacity, nominal voltage at full charge, voltage under load, self-discharge rate, ability to accept charge, charge-discharge cycle number, lifetime, temperature of the at least one cell during last use, total energy of charge and discharge, or any combination thereof.

In example 52, the subject matter of examples 47 to 51 include: wherein determining the hierarchy includes determining an ordered set of respective identifiers representing controllable elements.

In example 53, the subject matter of examples 47 to 52 includes: wherein adjusting the ordering of the hierarchy includes ordering at least a first portion of the hierarchy in an order of values of respective estimated states of the controllable elements.

In example 54, the subject matter of example 53 includes: wherein determining the hierarchy is performed such that controllable elements having states indicative of estimates of relatively higher performance capabilities are assigned to relatively higher positions in the first portion of the hierarchy and controllable elements having states indicative of estimates of relatively lower performance capabilities are assigned to relatively lower positions in the first portion of the hierarchy.

In example 55, the subject matter of example 54 includes: wherein the hierarchy level is further determined based on the current temperature of each controllable unit.

In example 56, the subject matter of example 55 includes: wherein the hierarchy is further determined based on a combination of an estimated state of charge (SoC) value, an estimated state of health (SoH) value, and a current temperature of each controllable unit, wherein the SoC value indicates a degree of charge of the at least one cell of the controllable unit relative to its capacity, and wherein the SoH value indicates a degree of degradation of the at least one cell of the controllable unit.

In example 57, the subject matter of examples 55 to 56 include: wherein, when the battery cells are operated in a discharged state, the controllable units allocated to the relatively higher positions in the hierarchy are activated for a longer duration than the controllable units allocated to the relatively lower positions in the hierarchy, when the respective controllable units of the controllable units are dynamically activated and deactivated.

In example 58, the subject matter of examples 55 to 57 includes: wherein, when each of the controllable units is dynamically activated and deactivated, the controllable unit assigned to a relatively higher position in the hierarchy is activated for a shorter duration than the controllable unit assigned to a relatively lower position in the hierarchy when the battery cell is operated in a charged state.

In example 59, the subject matter of examples 53-58 include: wherein adjusting the order of the hierarchy further comprises ordering a second portion of the hierarchy based on performance histories of certain of the controllable units.

In example 60, the subject matter of example 59 includes: wherein the second portion of the ordered set includes identifiers of certain controllable units that have undergone an activation duration according to a monomer dormancy criteria.

In example 61, the subject matter of examples 59 to 60 include: wherein a controllable element assigned to the second portion of the hierarchy is not activated when each of the controllable elements is dynamically activated and deactivated.

In example 62, the subject matter of examples 47 to 61 include: wherein, when each of the controllable units is dynamically activated and deactivated, the controllable units are sequentially activated and deactivated to generate a varying voltage waveform when the battery cells are operated in a discharged state.

In example 63, the subject matter of examples 47 to 62 include: wherein, when each of the controllable units is dynamically activated and deactivated, the controllable unit is activated and deactivated in response to power demand information received from a controller associated with the load when the battery cell is operating in a discharged state.

In example 64, the subject matter of examples 47-63 includes performing a debugging process adapted for deploying a new controllable unit, wherein: exposing the new controllable unit to an operating environment in which the plurality of controllable units are exposed; baseline measurements of the condition of the new controllable element; after a defined operating period, additional measurements are made of the condition of the new controllable unit; the baseline measurements and the additional measurements are used to generate an internal model of the new controllable unit; comparing the internal model with an empirical reference model to produce a comparison; based on the comparison result, a discovery status of the new controllable unit is estimated, wherein the discovery status indicates a performance capability of the controllable unit.

In example 65, the subject matter of example 64 includes: wherein the defined operating period comprises changing an operating condition for a duration sufficient to effect a change in the discovery state. In example 66, the subject matter of examples 64 to 65 include: wherein the internal model represents parameters including internal resistance and open circuit voltage.

Example 67 is a method for operating an energy storage system, the method comprising: providing a set of Battery Control Systems (BCSs), each BCS having a plurality of battery cells arranged as a plurality of controllable units, wherein each controllable unit comprises at least one of the plurality of battery cells; performing an individualized control on each of the controllable units, wherein the individualized control includes selectively activating/deactivating each controllable unit within the aggregate of battery cells; measuring a condition of at least one cell of each controllable unit; estimating a storage level of each BCS in the group; and adjusting the relative charge rate and the relative discharge rate of the battery cells between the set of BCSs based on the estimated energy level.

In example 68, the subject matter of example 67 includes: the relative charge rate and the relative discharge rate are adjusted such that a first BCS of the group having a relatively low energy storage level is controlled to charge and discharge at a relatively low rate and a second BCS of the group having a relatively high energy storage level is controlled to charge and discharge at a relatively high rate.

In example 69, the subject matter of examples 67 to 68 include: the relative charge rate and the relative discharge rate are adjusted such that a first BCS of the group having a relatively low energy storage level is controlled to discharge at a relatively low rate and charge at a relatively high rate, and a second BCS of the group having a relatively high energy storage level is controlled to discharge at a relatively high rate.

In example 70, the subject matter of examples 67 to 69 include: estimating a level of energy storage for each BCS based on a set of a combination of an estimated state of charge (SoC) value, an estimated state of health (SoH) value, and a nominal capacity for each controllable unit within the BCS, wherein the SoC value indicates a degree of charge of at least one cell of the controllable unit relative to its capacity, and wherein the SoH value indicates a degree of degradation of the at least one cell of the controllable unit.

In example 71, the subject matter of examples 67 to 70 include: the set of BCSs is operated in a charged state or a discharged state, and at least one BCS of the set is also operated simultaneously with the operation of the other BCSs of the set, sometimes in a different state from the other BCSs of the set.

Example 72 is at least one non-transitory machine-readable medium comprising instructions that, when executed by a controller of a battery control system having a plurality of battery cells arranged as a plurality of controllable units, each controllable unit comprising at least one of the plurality of battery cells, cause the battery control system to: measuring a condition of at least one cell of each controllable unit; estimating a state of each controllable unit based on the measured condition of the at least one battery cell in the controllable unit, wherein the estimated state is indicative of the performance capability of the controllable unit; determining a hierarchy of the plurality of controllable units, the hierarchy being based on respective states of the controllable units; dynamically activating and deactivating individual ones of the controllable units based on the hierarchy level such that a respective location of each of the controllable units within the hierarchy level is used to set an activation duration of the controllable unit; adjusting an order of the hierarchy in response to a change in the estimated state of one or more of the controllable units; and adjusting the order of the hierarchy in response to the operational history of one or more of the controllable units, regardless of any changes in the estimated states of those controllable units.

In example 73, the subject matter of example 72 includes: wherein the instructions, when executed, cause the battery control system to measure a condition of at least one battery cell of each controllable unit by measuring a voltage of the at least one cell, a current through the at least one cell, and a temperature of the at least one cell.

In example 74, the subject matter of examples 72 to 73 include: wherein the instructions, when executed, cause the battery control system to estimate the state of each controllable unit by estimating a state of charge (SoC) value that indicates the degree of charge of the at least one cell of each controllable unit relative to its capacity.

In example 75, the subject matter of example 74 includes: wherein the instructions, when executed, cause the battery control system to estimate a state of each controllable unit by estimating a state of health (SoH) value, wherein the SoH value indicates a degree of degradation of the at least one cell of each controllable unit.

In example 76, the subject matter of example 75 includes: wherein the SoH value is determined based on at least one condition of the at least one monomer, the at least one condition selected from the group consisting of: internal resistance, capacity, nominal voltage at full charge, voltage under load, self-discharge rate, ability to accept charge, charge-discharge cycle number, lifetime, temperature of the at least one cell during last use, total energy of charge and discharge, or any combination thereof.

In example 77, the subject matter of examples 72 to 76 includes: wherein the instructions, when executed, cause the battery control system to determine the hierarchy by determining an ordered set of respective identifiers representing the controllable elements.

In example 78, the subject matter of examples 72 to 77 include: wherein the instructions, when executed, cause the battery control system to adjust the ordering of the hierarchy by ordering at least a first portion of the hierarchy in an order of values of respective estimated states of the controllable units.

In example 79, the subject matter of example 78 includes: wherein the instructions, when executed, cause the battery control system to determine a hierarchy such that controllable units having estimated states indicative of relatively higher performance capabilities are assigned to relatively higher locations in a first portion of the hierarchy and controllable units having estimated states indicative of relatively lower performance capabilities are assigned to relatively lower locations in the first portion of the hierarchy.

In example 80, the subject matter of example 79 includes: wherein the hierarchy level is further determined according to an instruction based on the current temperature of each controllable unit.

In example 81, the subject matter of example 80 includes: wherein the hierarchy is further determined according to the instructions based on a combination of an estimated state of charge (SoC) value, an estimated state of health (SoH) value, and a current temperature of each controllable unit, wherein the SoC value indicates a degree of charge of at least one cell of the controllable unit relative to its capacity, and wherein the SoH value indicates a degree of degradation of the at least one cell of the controllable unit.

In example 82, the subject matter of examples 80 to 81 include: wherein the instructions, when executed, cause the battery control system to dynamically activate and deactivate the respective ones of the controllable units such that when the battery cells are operating in a discharged state, the controllable units assigned to relatively higher positions in the hierarchy are activated for a longer duration than the controllable units assigned to relatively lower positions in the hierarchy.

In example 83, the subject matter of examples 80 to 82 includes: wherein the instructions, when executed, cause the battery control system to dynamically activate and deactivate individual ones of the controllable units such that when the battery cells are operating in a charged state, the controllable units assigned to relatively higher positions in the hierarchy are activated for a shorter duration than the controllable units assigned to relatively lower positions in the hierarchy.

In example 84, the subject matter of examples 78 to 83 include: wherein the instructions, when executed, cause the battery control system to adjust the ordering of the hierarchy by ordering the second portion of the hierarchy through the performance history of some of the controllable units.

In example 85, the subject matter of example 84 includes: wherein the second portion of the ordered set includes identifiers of certain controllable units that have undergone an activation duration according to a monomer dormancy criteria.

In example 86, the subject matter of examples 84 to 85 include: wherein the instructions, when executed, cause the battery control system to dynamically activate and deactivate individual ones of the controllable units, leaving controllable units assigned to the second portion of the hierarchy inactive.

In example 87, the subject matter of examples 72 to 86 include: wherein the instructions, when executed, cause the battery control system to dynamically activate and deactivate each of the controllable units such that when the battery cells are operating in a discharged state, the controllable units are sequentially activated and deactivated to produce a varying voltage waveform.

In example 88, the subject matter of examples 72 to 87 includes: wherein the instructions, when executed, cause the battery control system to dynamically activate and deactivate each of the controllable units such that when the battery cells are operating in a discharged state, the controllable units are activated and deactivated in response to power demand information received from a controller associated with the load.

In example 89, the subject matter of examples 72 to 88 includes: wherein the instructions, when executed, cause the battery control system to perform a debugging process adapted for deploying a new controllable unit, wherein: exposing the new controllable unit to an operating environment in which the plurality of controllable units are exposed; baseline measurements of the condition of the new controllable element; after a defined operating period, additional measurements are made of the condition of the new controllable unit; the baseline measurements and the additional measurements are used to generate an internal model of the new controllable unit; comparing the internal model with an empirical reference model to produce a comparison; based on the comparison result, a discovery status of the new controllable unit is estimated, wherein the discovery status indicates a performance capability of the controllable unit.

In example 90, the subject matter of example 89 includes: wherein the defined operating period comprises changing an operating condition for a duration sufficient to effect a change in the discovery state.

In example 91, the subject matter of examples 89 to 90 include: wherein the internal model represents parameters including internal resistance and open circuit voltage.

Example 92 is at least one non-transitory machine readable medium comprising instructions that, when executed by a controller of an energy storage system comprising a set of Battery Control Systems (BCSs), each BCS having a plurality of battery cells arranged as a plurality of controllable units, wherein each controllable unit comprises at least one of the plurality of battery cells, cause the energy storage system to: performing an individualized control on each of the controllable units, wherein the individualized control includes selectively activating/deactivating each controllable unit within the aggregate of battery cells; measuring a condition of at least one cell of each controllable unit; estimating a storage level of each BCS in the group; and adjusting the relative charge rate and the relative discharge rate of the battery cells between the set of BCSs based on the estimated energy level.

In example 93, the subject matter of example 92 includes: the instructions, when executed, cause the energy storage system to: the relative charge rate and the relative discharge rate are adjusted such that a first BCS of the group having a relatively low energy storage level is controlled to charge and discharge at a relatively low rate and a second BCS of the group having a relatively high energy storage level is controlled to charge and discharge at a relatively high rate.

In example 94, the subject matter of examples 92 to 93 includes: the instructions, when executed, cause the energy storage system to: the relative charge rate and the relative discharge rate are adjusted such that a first BCS of the group having a relatively low energy storage level is controlled to discharge at a relatively low rate and charge at a relatively high rate, and a second BCS of the group having a relatively high energy storage level is controlled to discharge at a relatively high rate.

In example 95, the subject matter of examples 92 to 94 includes: the instructions, when executed, cause the energy storage system to: estimating a level of energy storage for each BCS based on a set of a combination of an estimated state of charge (SoC) value, an estimated state of health (SoH) value, and a nominal capacity for each controllable unit within the BCS, wherein the SoC value indicates a degree of charge of at least one cell of the controllable unit relative to its capacity, and wherein the SoH value indicates a degree of degradation of the at least one cell of the controllable unit.

In example 96, the subject matter of examples 92 to 95 include: the instructions, when executed, cause the energy storage system to: the set of BCSs is operated in a charged state or a discharged state, and at least one BCS of the set is also operated in a state that is sometimes different from other BCSs of the set, simultaneously with the operation of the other BCSs of the set.

Conclusion(s)

In the above description, certain specific details are set forth in order to provide a thorough understanding of various disclosed embodiments. One skilled in the relevant art will recognize, however, that the implementations may be practiced without one or more of the specific details, or with other methods, components, materials, etc. In other instances, well-known structures associated with computer systems, server computers, or communication networks may be used without detail to avoid unnecessarily obscuring the description of the implementations.

The foregoing detailed description has set forth various embodiments of the devices or processes via the use of block diagrams, schematics, and examples. Insofar as such block diagrams, schematics, and examples contain one or more functions or operations, it will be understood by those within the art that each function or operation within such block diagrams, flowcharts, or examples can be implemented, individually or collectively, by a wide range of hardware, software, firmware, or virtually any combination thereof. In one embodiment, the present subject matter may be implemented via an Application Specific Integrated Circuit (ASIC). However, those skilled in the art will recognize that the embodiments disclosed herein, in whole or in part, can be equivalently implemented in standard integrated circuits, as one or more computer programs running on one or more computers (e.g., as one or more programs running on one or more computer systems), as one or more programs running on one or more controllers (e.g., microcontrollers), as one or more programs communicating on one or more processors (e.g., microprocessors), as firmware, or as virtually any combination thereof, and that designing the circuitry or writing the code for the software and/or firmware would be well within the skill of one of ordinary skill in the art in light of this disclosure.

In addition, those skilled in the art will appreciate that the mechanisms taught herein are capable of being stored as a program product in a variety of forms, and that an illustrative embodiment applies equally regardless of the particular type of physical storage media used to actually carry out the distribution. Examples of such media include, but are not limited to, the following: read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM) (e.g., flash memory device), magnetic disk, optical disk, static or dynamic Random Access Memory (RAM), cache memory, and the like, or any combination of these or other media.

U.S. International patent application PCT/CA2019/051238 published as WO 2020/047663 is incorporated herein by reference.

The various embodiments described above may be combined to provide further embodiments. Aspects of the embodiments can be modified, if necessary, to employ systems, circuits and concepts of the various patents, applications and publications identified herein to provide yet further embodiments.

While there have been shown, described, and pointed out fundamental novel features of the invention as applied to a preferred embodiment thereof, it will be understood that various omissions and substitutions and changes in the form and details of the devices illustrated, and in their operation, may be made by those skilled in the art without departing from the basic teachings thereof. For example, it is expressly intended that all combinations of those elements or method acts which perform substantially the same function in substantially the same way to achieve the same results are within the scope. Furthermore, it should be recognized that structures or elements or method acts shown or described in connection with any disclosed form or embodiment may be incorporated in any other disclosed or described or suggested form or embodiment as a general matter of design choice. Accordingly, it is intended that the scope of the claims be limited only as indicated by the scope of the claims appended hereto.

The embodiments described herein are not meant to be an exhaustive presentation of the various features of the disclosed subject matter in any combination. Thus, embodiments are not mutually exclusive combinations of features; rather, the invention may include combinations of different individual features selected from different individual embodiments, as will be appreciated by those of ordinary skill in the art.

Any incorporation by reference of documents above is limited such that no subject matter is incorporated that is contrary to the explicit disclosure herein. The incorporation by reference of any such documents is further limited such that no claim included in the document is incorporated by reference into the claims of the present application. However, unless expressly excluded, the claims of any document are incorporated as part of this disclosure. The incorporation by reference of any of the above documents is further limited such that any definitions provided in the documents are not incorporated by reference herein unless expressly included herein.

For purposes of interpreting the claims of the present invention, the 35USC ≡112 (f) specification should not be referred to unless the claims recite the specific term "means for … …" or "for … … steps".

Claims (96)

1. A battery control system, comprising:

a first plurality of switching circuits, each of the switching circuits of the first plurality of switching circuits including a respective high-side switch, a respective low-side switch, and a respective battery cell, the high-side switch being selectively operable to couple a voltage of the respective battery cell into an accumulated voltage of the first plurality of switching circuits in an on setting of the high-side switch, and the respective low-side switch being selectively operable to omit a voltage of the respective battery cell in the accumulated voltage of the first plurality of switching circuits in an on setting of the low-side switch; and

a first switch control circuit communicatively coupled to control respective settings of the respective high-side switch and the respective low-side switch of each of the switching circuits of the first plurality of switching circuits.

2. The battery control system of claim 1, wherein the respective high-side switch and the respective low-side switch of each of the switching circuits are electrically coupled in a half-bridge arrangement and operate in a complementary manner with one of the respective high-side switch and the respective low-side switch each in a respective on setting with dead time in which both the respective high-side switch and the respective low-side switch are in respective off settings prior to switching to the respective on setting of the respective high-side switch or the respective low-side switch.

3. The battery control system of claim 1, wherein the first plurality of m battery cells is arranged in a first rack; and further comprising:

a number N of additional plurality of switching circuits, each of the switching circuits of the additional plurality of switching circuits including a respective high-side switch, a respective low-side switch, and a respective battery cell, the high-side switch being selectively operable to couple a voltage of the respective battery cell into an accumulated voltage of the first plurality of switching circuits in an on setting of the high-side switch, and the respective low-side switch being selectively operable to omit a voltage of the respective battery cell in the accumulated voltage of the first plurality of switching circuits in an on setting of the low-side switch; and

a number N of additional switch control circuits communicatively coupled to control respective high-side switches and respective settings of respective low-side switches of each of the switch circuits of respective additional switch circuits of the additional plurality of switch circuits.

4. The battery control system of claim 3, wherein the battery cells of each of the additional plurality of switching circuits are disposed on a respective one of a plurality of additional racks other than the first rack.

5. The battery control system of claim 4, further comprising:

and a cable bundle electrically coupling the battery cells of the first rack and the additional rack in series.

6. The battery control system according to any one of claims 1 to 5, further comprising:

at least a first inverter comprising a plurality of switches electrically coupled in a full H-bridge topology, the first inverter having a set of input nodes and a set of output nodes, the set of input nodes electrically coupled to a power source, and the set of output nodes electrically coupled to switching circuitry of at least the first plurality of switching circuitry; and

a battery control system control circuit communicatively coupled with at least the first switch control circuit.

7. The battery control system of claim 6, wherein the power source provides a plurality of phases of power via a power grid, the first inverter is a first power grid inverter coupled to a first phase of power provided via the power grid, and further comprising:

a plurality of additional grid-tie inverters electrically coupling respective phases of power provided via the grid.

8. The battery control system of claim 6, wherein the battery control system control circuit controls the first inverter to rectify a negative voltage of a power supply to a positive voltage for connection with a battery cell of the switching circuit, wherein the first inverter operates at a switching frequency that is at least twice a waveform frequency provided by the power supply.

9. The battery control system of claim 6, wherein the battery control system control circuit controls the first inverter to adjust the current provided by the power source to charge or discharge the battery cells in accordance with a set point, and the battery control system control circuit sends a set of switch commands to the switch circuit.

10. The battery control system of claim 6, wherein the battery control system control circuit controls the first inverter according to an optimization algorithm to select which one or more cells should be charged or discharged at a current level so as to maximize the respective life of each of the cells.

11. The battery control system of claim 10, wherein the battery control system control circuit implements a ranking order of cell voltages based on virtual locations of cells in a serial string defined by an optimization algorithm output.

12. The battery control system of claim 6, wherein each switching circuit includes a respective voltage sensor and a respective temperature sensor, and transmits battery information including the sensed voltage and sensed temperature of the respective battery cell to the battery control system control circuit or a central controller.

13. The battery control system of claim 6, wherein the battery control system control circuit executes a grid current control algorithm based on a charge/discharge power set point and a voltage provided by the power source to provide one or more control signals to at least the first switch control circuit.

14. The battery control system of claim 13, wherein the battery control system control circuit compares the control signal to voltages of all battery cells to generate respective settings for the high-side and low-side switches of the respective battery cells and transmits the generated settings to the respective switching circuits.

15. The battery control system of claim 6, wherein the charge and discharge current of each individual one of the battery cells is controlled based on the state of charge and state of health of the respective battery cell.

16. The battery control system of claim 4, further comprising:

a cable bundle that correctly matches the polarity of the battery cells to a set of inverter terminals.

17. The battery control system of any one of claims 1, 2, or 6, wherein the first switch control circuit controls timing of respective settings of the respective high-side switches and the respective low-side switches of each of the switch circuits of the first plurality of switch circuits to produce a stepped multiplexed output voltage resembling a positive portion of a sinusoidal waveform.

18. A method of operating a battery control system, comprising:

receiving, by a battery control system controller, battery information for one or more battery cells from a switching circuit;

creating, by the switch control circuit, a ranking order based at least in part on the virtual location of each cell in the serial string and the battery information;

executing, by the switch control circuit, a grid current control algorithm based on a charge/discharge power set point and a grid voltage;

outputting control signals to control the one or more battery cells to meet power/voltage requirements;

comparing, by the switch control circuit, a control signal with all cell information to generate a switch setting for each of the one or more cells;

the switch settings for each of the one or more battery cells are transmitted to the switch circuit.

19. The method of claim 18, wherein the battery information is at least one of voltage and temperature.

20. The method of claim 19, wherein the battery information is provided by one or more sensors.

21. The method of claim 18, wherein the ordering order is based at least in part on an optimization algorithm output.

22. A battery control system, comprising:

a plurality of battery cells arranged as a plurality of controllable units, wherein each controllable unit comprises at least one of the plurality of battery cells;

a switching circuit coupled to the plurality of battery cells and arranged to facilitate individualized control of each of the controllable units, wherein the individualized control includes selectively activating/deactivating each controllable unit within an aggregate of battery cells;

a sensing circuit disposed at each controllable unit to measure a condition of at least one battery cell of the controllable unit; and

a controller circuit operably coupled to the switching circuit and the sensing circuit, the controller circuit operable to read the sensing circuit and cause the switching circuit to dynamically activate and deactivate controllable units within the collection of battery cells based on individualized control according to battery management instructions;

wherein the battery management instructions, when executed, cause the controller circuit to:

estimating a state of each controllable unit based on a measured condition of at least one battery cell in the controllable unit, wherein the estimated state is indicative of a performance capability of the controllable unit;

Determining a hierarchy of the plurality of controllable units, the hierarchy being based on respective states of the controllable units;

performing the individualized control based on the hierarchy level such that a respective position of each of the controllable units within the hierarchy level is used to set an activation duration of that controllable unit within the aggregate of battery cells;

adjusting an order of the hierarchy in response to a change in the estimated state of one or more of the controllable units; and

the order of the hierarchy is adjusted responsive to the operational history of one or more of the controllable units, regardless of any changes in the estimated states of those controllable units.

23. The battery control system of claim 22, wherein the condition associated with each controllable unit measured by the sensing circuit includes a voltage of at least one cell of the controllable unit, a current through at least one cell of the controllable unit, and a temperature of at least one cell of the controllable unit.

24. The battery control system of claim 22, wherein the state estimated by the controller circuit comprises a state of charge (SoC) value indicating a degree of charge of at least one cell of the controllable unit relative to its capacity.

25. The battery control system of claim 24, wherein the state estimated by the controller circuit further comprises a state of health (SoH) value indicating a degree of degradation of at least one cell of the controllable unit.

26. The battery control system of claim 25, wherein the SoH value is determined based on at least one condition of the at least one cell selected from the group consisting of: internal resistance, capacity, nominal voltage at full charge, voltage under load, self-discharge rate, ability to accept charge, charge-discharge cycle number, lifetime, temperature of the at least one cell during last use, total energy of charge and discharge, or any combination thereof.

27. The battery control system of claim 25, wherein the hierarchy includes an ordered set of respective identifiers representing controllable units.

28. The battery control system of claim 22, wherein at least a first portion of the hierarchy is ordered in an order of values of the respective estimated states of the controllable units.

29. The battery control system of claim 28, wherein the battery management instructions, when executed, cause the controller circuit to determine the hierarchy such that controllable elements having estimated states indicative of relatively higher performance capabilities are assigned to relatively higher locations in a first portion of the hierarchy and controllable elements having estimated states indicative of relatively lower performance capabilities are assigned to relatively lower locations in the first portion of the hierarchy.

30. The battery control system of claim 29, wherein the hierarchy level is further determined based on a current temperature of each controllable unit.

31. The battery control system of claim 30, wherein the hierarchy level is further determined based on a combination of an estimated state of charge (SoC) value, an estimated state of health (SoH) value, and a current temperature for each controllable unit, wherein the SoC value indicates a degree of charge of at least one cell of a controllable unit relative to its capacity, and wherein the SoH value indicates a degree of degradation of at least one cell of the controllable unit.

32. The battery control system according to claim 30, wherein in the individualization control, when the battery cell is operated in a discharge state, the controllable unit allocated to a relatively higher position in the hierarchy is activated for a longer duration than the controllable unit allocated to a relatively lower position in the hierarchy.

33. The battery control system of claim 30, wherein in the individualized control, when the battery cells are operating in a charged state, the controllable units assigned to relatively higher positions in the hierarchy are activated for a shorter duration than the controllable units assigned to relatively lower positions in the hierarchy.

34. The battery control system of claim 28, wherein the second portion of the hierarchy is ordered based on a performance history of some of the controllable units.

35. The battery control system of claim 34, wherein the second portion of the ordered set includes identifiers of certain controllable units that have undergone an activation duration according to a monomer sleep criteria.

36. The battery control system of claim 34, wherein in the individualized control, controllable units assigned to the second portion of the hierarchy are not activated.

37. The battery control system of claim 22, wherein the switching circuit comprises controllable units arranged in series, and wherein in the individualized control, when the battery cells are operating in a discharged state, the controllable units arranged in series are sequentially activated and deactivated to produce a varying voltage waveform.

38. The battery control system of claim 22, wherein in the individualized control, the controllable unit is activated and deactivated in response to power demand information received from a controller associated with a load when the battery cells are operating in a discharged state.

39. The battery control system of claim 22, wherein the battery management instructions, when executed, cause the controller circuit to perform a debugging process adapted for deploying a new controllable unit, wherein:

the switching circuit exposes the new controllable unit to an operating environment in which the plurality of controllable units are exposed;

performing a baseline measurement of the condition of the new controllable element;

after a defined period of operation, additional measurements are made of the condition of the new controllable unit;

the baseline measurements and the additional measurements are used to generate an internal model of the new controllable unit;

comparing the internal model with an empirical reference model to produce a comparison;

based on the comparison result, a discovery status of the new controllable unit is estimated, wherein the discovery status indicates a performance capability of the controllable unit.

40. The battery control system of claim 39, wherein the defined operating period comprises changing an operating condition for a duration sufficient to effect a change in the discovery state.

41. The battery control system of claim 39, wherein the internal model represents parameters including internal resistance and open circuit voltage.

42. An energy storage system, comprising:

a set of Battery Control Systems (BCSs), each BCS comprising:

a plurality of battery cells arranged as a plurality of controllable units, wherein each controllable unit comprises at least one of the plurality of battery cells;

a switching circuit coupled to the plurality of battery cells and arranged to facilitate individualized control of each of the controllable units, wherein the individualized control includes selectively activating/deactivating each controllable unit within an aggregate of battery cells;

a sensing circuit disposed at each controllable unit to measure a condition of at least one battery cell of the controllable unit;

a system controller operatively coupled to the switching circuit and the sensing circuit, the system controller being operable to:

estimating a storage level of each BCS in the group; and

the relative charge rate and the relative discharge rate of the battery cells in the set of BCSs are adjusted based on the estimated energy levels.

43. The energy storage system of claim 42 wherein the system controller is operable to adjust the relative charge rate and the relative discharge rate such that a first BCS of the group having a relatively lower energy storage level is controlled to charge and discharge at a relatively lower rate and a second BCS of the group having a relatively higher energy storage level is controlled to charge and discharge at a relatively higher rate.

44. The energy storage system of claim 42 wherein the system controller is operable to adjust the relative charge rate and the relative discharge rate such that a first BCS of the group having a relatively low energy storage level is controlled to discharge at a relatively low rate and charge at a relatively high rate and a second BCS of the group having a relatively high energy storage level is controlled to discharge at a relatively high rate.

45. The energy storage system of claim 42, wherein the system controller is operable to estimate the energy storage level of each BCS based on a set of a combination of an estimated state of charge (SoC) value, an estimated state of health (SoH) value, and a nominal capacity for each controllable unit within the BCS, wherein the SoC value is indicative of a degree of charge of at least one cell of the controllable unit relative to its capacity, and wherein the SoH value is indicative of a degree of degradation of at least one cell of the controllable unit.

46. The energy storage system of claim 42 wherein the system controller is operable to cause the set of BCSs to operate in a charged state or a discharged state and also to cause at least one BCS of the set to operate simultaneously with the operation of the other BCSs of the set, sometimes in a different state than the other BCSs of the set.

47. A method for operating a battery control system having a plurality of battery cells arranged as a plurality of controllable units, each controllable unit including at least one of the plurality of battery cells, the method comprising:

measuring a condition of at least one cell of each controllable unit;

estimating a state of each controllable unit based on a measured condition of at least one battery cell in the controllable unit, wherein the estimated state is indicative of a performance capability of the controllable unit;

determining a hierarchy of the plurality of controllable units, the hierarchy being based on respective states of the controllable units;

dynamically activating and deactivating each of the controllable units based on the hierarchy level such that a respective position of each of the controllable units within the hierarchy level is used to set an activation duration of that controllable unit;

adjusting an order of the hierarchy in response to a change in the estimated state of one or more of the controllable units; and

the order of the hierarchy is adjusted responsive to the operational history of one or more of the controllable units, regardless of any changes in the estimated states of those controllable units.

48. The method of claim 47, wherein measuring a condition of at least one cell of each controllable unit comprises measuring a voltage of the at least one cell, a current through the at least one cell, and a temperature of the at least one cell.

49. The method of claim 47, wherein estimating the state of each controllable unit comprises estimating a state of charge (SoC) value that indicates a degree of charge of at least one cell of each controllable unit relative to its capacity.

50. The method of claim 49, wherein estimating the state of each controllable unit further comprises estimating a state of health (SoH) value that indicates a degree of degradation of at least one monomer of each controllable unit.

51. The method of claim 50, wherein the SoH value is determined based on at least one condition of the at least one monomer, the at least one condition selected from the group consisting of: internal resistance, capacity, nominal voltage at full charge, voltage under load, self-discharge rate, ability to accept charge, charge-discharge cycle number, lifetime, temperature of the at least one cell during last use, total energy of charge and discharge, or any combination thereof.

52. The method of claim 47, wherein determining the hierarchy level includes determining an ordered set of respective identifiers representing the controllable elements.

53. The method of claim 47, wherein adjusting the order of the hierarchy comprises ordering at least a first portion of the hierarchy in an order of values of respective estimated states of the controllable elements.

54. The method of claim 53, wherein determining a hierarchy is performed such that controllable elements having states indicative of estimates of relatively higher performance capabilities are assigned to relatively higher positions in a first portion of the hierarchy and controllable elements having states indicative of estimates of relatively lower performance capabilities are assigned to relatively lower positions in the first portion of the hierarchy.

55. The method of claim 54, wherein the hierarchy level is further determined based on a current temperature of each controllable element.

56. The method of claim 55, wherein the hierarchy level is further determined based on a combination of an estimated state of charge (SoC) value, an estimated state of health (SoH) value, and a current temperature for each controllable unit, wherein the SoC value indicates a degree of charge of at least one cell of the controllable unit relative to its capacity, and wherein the SoH value indicates a degree of degradation of the at least one cell of the controllable unit.

57. The method of claim 55, wherein, when each of the controllable units is dynamically activated and deactivated, the controllable unit assigned to a relatively higher position in the hierarchy is activated for a longer duration than the controllable unit assigned to a relatively lower position in the hierarchy when the battery cell is operated in a discharged state.

58. The method of claim 55, wherein, when each of the controllable units is dynamically activated and deactivated, the controllable unit assigned to a relatively higher position in the hierarchy is activated for a shorter duration than the controllable unit assigned to a relatively lower position in the hierarchy when the battery cell is operating in a charged state.

59. The method of claim 53, wherein adjusting the order of the hierarchy further comprises ordering a second portion of the hierarchy based on performance histories of certain ones of the controllable units.

60. The method of claim 59, wherein the second part of the ordered set includes identifiers of certain controllable elements that have undergone an activation duration according to a monomer dormancy criteria.

61. The method of claim 59, wherein a controllable element assigned to the second part of the hierarchy is not activated when each of the controllable elements is dynamically activated and deactivated.

62. The method of claim 47, wherein, when each of the controllable units is dynamically activated and deactivated, the controllable units are sequentially activated and deactivated to produce a varying voltage waveform when the battery cells are operated in a discharged state.

63. The method of claim 47, wherein, when each of the controllable units is dynamically activated and deactivated, the controllable unit is activated and deactivated in response to power demand information received from a controller associated with a load when a battery cell is operating in a discharged state.

64. The method of claim 47, further comprising performing a debugging process adapted for deploying the new controllable element, wherein:

the new controllable unit is exposed to an operating environment in which the plurality of controllable units are exposed;

performing a baseline measurement of the condition of the new controllable element;

after a defined period of operation, additional measurements are made of the condition of the new controllable unit;

The baseline measurements and the additional measurements are used to generate an internal model of the new controllable unit;

comparing the internal model with an empirical reference model to produce a comparison; and

based on the comparison result, a discovery status of the new controllable unit is estimated, wherein the discovery status indicates a performance capability of the controllable unit.

65. The method of claim 64, wherein the defined period of operation includes changing an operating condition for a duration sufficient to effect a change in the discovery state.

66. The method of claim 64, wherein the internal model represents parameters including internal resistance and open circuit voltage.

67. A method for operating an energy storage system, the method comprising:

providing a set of Battery Control Systems (BCSs), each BCS having a plurality of battery cells arranged as a plurality of controllable units, wherein each controllable unit comprises at least one of the plurality of battery cells;

performing an individualized control on each of the controllable units, wherein the individualized control includes selectively activating/deactivating each controllable unit within an aggregate of battery cells;

measuring a condition of at least one cell of each controllable unit;

Estimating a storage level of each BCS in the group; and

the relative charge rate and the relative discharge rate of the battery cells between the set of BCSs are adjusted based on the estimated energy levels.

68. The method of claim 67, further comprising:

the relative charge rate and the relative discharge rate are adjusted such that a first BCS of the group having a relatively lower energy storage level is controlled to charge and discharge at a relatively lower rate and a second BCS of the group having a relatively higher energy storage level is controlled to charge and discharge at a relatively higher rate.

69. The method of claim 67, further comprising:

the relative charge rate and the relative discharge rate are adjusted such that a first BCS of the group having a relatively low energy storage level is controlled to discharge at a relatively low rate and charge at a relatively high rate, and a second BCS of the group having a relatively high energy storage level is controlled to discharge at a relatively high rate.

70. The method of claim 67, further comprising:

estimating a level of energy storage for each of the BCSs based on a set of a combination of an estimated state of charge (SoC) value, an estimated state of health (SoH) value, and a nominal capacity for each of the controllable units within the BCS, wherein the SoC value indicates a degree of charge of at least one of the controllable units relative to its capacity, and wherein the SoH value indicates a degree of degradation of at least one of the controllable units.

71. The method of claim 67, further comprising:

the set of BCSs is operated in a charged state or a discharged state, and at least one BCS of the set is also operated simultaneously with the operation of the other BCSs of the set, sometimes in a different state from the other BCSs of the set.

72. At least one non-transitory machine-readable medium comprising instructions that, when executed by a controller of a battery control system having a plurality of battery cells arranged as a plurality of controllable units, each controllable unit comprising at least one of the plurality of battery cells, cause the battery control system to:

measuring a condition of at least one cell of each controllable unit;

estimating a state of each controllable unit based on the measured condition of the at least one battery cell in the controllable unit, wherein the estimated state is indicative of the performance capability of the controllable unit;

determining a hierarchy of the plurality of controllable units, the hierarchy being based on respective states of the controllable units;

dynamically activating and deactivating individual ones of the controllable units based on the hierarchy level such that a respective position of each of the controllable units within the hierarchy level is used to set an activation duration of that controllable unit;

Adjusting an order of the hierarchy in response to a change in the estimated state of one or more of the controllable units; and

the order of the hierarchy is adjusted responsive to the operational history of one or more of the controllable units, regardless of any changes in the estimated states of those controllable units.

73. The at least one non-transitory machine readable medium of claim 72, wherein the instructions, when executed, cause the battery control system to measure a condition of at least one battery cell of each controllable unit by measuring a voltage of the at least one cell, a current through the at least one cell, and a temperature of the at least one cell.

74. The at least one non-transitory machine readable medium of claim 72, wherein the instructions, when executed, cause the battery control system to estimate the state of each controllable unit by estimating a state of charge (SoC) value, wherein the state of charge (SoC) value indicates a degree of charge of at least one cell of each controllable unit relative to its capacity.

75. The at least one non-transitory machine readable medium of claim 74, wherein the instructions, when executed, cause the battery control system to estimate a state of each controllable unit by estimating a state of health (SoH) value, wherein the SoH value indicates a degree of degradation of the at least one cell of each controllable unit.

76. The at least one non-transitory machine-readable medium of claim 75, wherein the SoH value is determined based on at least one condition of the at least one monomer selected from the group consisting of: internal resistance, capacity, nominal voltage at full charge, voltage under load, self-discharge rate, ability to accept charge, charge-discharge cycle number, lifetime, temperature of the at least one cell during last use, total energy of charge and discharge, or any combination thereof.

77. The at least one non-transitory machine readable medium of claim 72, wherein the instructions, when executed, cause the battery control system to determine the hierarchy by determining an ordered set of respective identifiers representing the controllable units.

78. The at least one non-transitory machine readable medium of claim 72, wherein the instructions, when executed, cause the battery control system to adjust the order of the hierarchy by ordering at least a first portion of the hierarchy in an order of values of respective estimated states of the controllable units.

79. The at least one non-transitory machine readable medium of claim 78, wherein the instructions, when executed, cause the battery control system to determine the hierarchy such that controllable elements having estimated states indicative of relatively higher performance capabilities are assigned to relatively higher positions in a first portion of the hierarchy and controllable elements having estimated states indicative of relatively lower performance capabilities are assigned to relatively lower positions in the first portion of the hierarchy.

80. The at least one non-transitory machine readable medium of claim 79, wherein the hierarchy level is further determined according to instructions based on a current temperature of each controllable unit.

81. The at least one non-transitory machine readable medium of claim 80, wherein the hierarchy is further determined according to instructions based on a combination of an estimated state of charge (SoC) value, an estimated state of health (SoH) value, and a current temperature for each controllable unit, wherein the SoC value indicates a degree of charge of at least one cell of the controllable unit relative to its capacity, and wherein the SoH value indicates a degree of degradation of the at least one cell of the controllable unit.

82. The at least one non-transitory machine readable medium of claim 80, wherein the instructions, when executed, cause the battery control system to dynamically activate and deactivate the respective ones of the controllable units such that a controllable unit assigned to a relatively higher position in the hierarchy is activated for a longer duration than a controllable unit assigned to a relatively lower position in the hierarchy when the battery cell is operating in a discharged state.

83. The at least one non-transitory machine readable medium of claim 80, wherein the instructions, when executed, cause the battery control system to dynamically activate and deactivate the respective ones of the controllable units such that, when the battery cells are operating in a charged state, a controllable unit assigned to a relatively higher position in the hierarchy is activated for a shorter duration than a controllable unit assigned to a relatively lower position in the hierarchy.

84. The at least one non-transitory machine readable medium of claim 78, wherein the instructions, when executed, cause the battery control system to adjust the order of the hierarchy by ordering the second portion of the hierarchy through a performance history of some of the controllable units.

85. The at least one non-transitory machine readable medium of claim 84, wherein the second portion of the ordered set comprises identifiers of certain controllable elements that have undergone an activation duration according to a monomer dormancy criterion.

86. The at least one non-transitory machine readable medium of claim 84, wherein the instructions, when executed, cause the battery control system to dynamically activate and deactivate respective ones of the controllable units, leaving controllable units assigned to the second portion of the hierarchy inactive.

87. The at least one non-transitory machine readable medium of claim 72, wherein the instructions, when executed, cause the battery control system to dynamically activate and deactivate each controllable unit of the controllable units such that when the battery cells are operating in a discharged state, the controllable units are sequentially activated and deactivated to produce a varying voltage waveform.

88. The at least one non-transitory machine readable medium of claim 72, wherein the instructions, when executed, cause the battery control system to dynamically activate and deactivate each controllable unit of the controllable units such that when the battery cells are operating in a discharged state, the controllable units are activated and deactivated in response to power demand information received from a controller associated with a load.

89. The at least one non-transitory machine readable medium of claim 72, wherein the instructions, when executed, cause the battery control system to perform a debugging process adapted for deploying a new controllable unit, wherein:

the new controllable unit is exposed to an operating environment in which the plurality of controllable units are exposed;

performing a baseline measurement of the condition of the new controllable element;

after a defined period of operation, additional measurements are made of the condition of the new controllable unit;

the baseline measurements and the additional measurements are used to generate an internal model of the new controllable unit;

comparing the internal model with an empirical reference model to produce a comparison;

based on the comparison result, a discovery status of the new controllable unit is estimated, wherein the discovery status indicates a performance capability of the controllable unit.

90. The at least one non-transitory machine-readable medium of claim 89, wherein the defined period of operation includes changing an operating condition for a duration sufficient to effect a change in the discovery state.

91. The at least one non-transitory machine-readable medium of claim 89, wherein the internal model represents parameters including internal resistance and open circuit voltage.

92. At least one non-transitory machine-readable medium comprising instructions that, when executed by a controller of an energy storage system comprising a set of Battery Control Systems (BCSs), each BCS having a plurality of battery cells arranged as a plurality of controllable units, each controllable unit comprising at least one of the plurality of battery cells, cause the energy storage system to:

performing an individualized control on each of the controllable units, wherein the individualized control includes selectively activating/deactivating each controllable unit within an aggregate of battery cells;

measuring a condition of at least one cell of each controllable unit;

estimating a storage level of each BCS in the group; and

the relative charge rate and the relative discharge rate of the battery cells between the set of BCSs are adjusted based on the estimated energy levels.

93. The at least one non-transitory machine-readable medium of claim 92, further comprising instructions that, when executed, cause the energy storage system to:

the relative charge rate and the relative discharge rate are adjusted such that a first BCS of the group having a relatively lower energy storage level is controlled to charge and discharge at a relatively lower rate and a second BCS of the group having a relatively higher energy storage level is controlled to charge and discharge at a relatively higher rate.

94. The at least one non-transitory machine-readable medium of claim 92, further comprising instructions that, when executed, cause the energy storage system to:

the relative charge rate and the relative discharge rate are adjusted such that a first BCS of the group having a relatively low energy storage level is controlled to discharge at a relatively low rate and charge at a relatively high rate, and a second BCS of the group having a relatively high energy storage level is controlled to discharge at a relatively high rate.

95. The at least one non-transitory machine-readable medium of claim 92, further comprising instructions that, when executed, cause the energy storage system to:

estimating a level of energy storage for each BCS based on a set of a combination of an estimated state of charge (SoC) value, an estimated state of health (SoH) value, and a nominal capacity for each controllable unit within the BCS, wherein the SoC value indicates a degree of charge of at least one cell of the controllable unit relative to its capacity, and wherein the SoH value indicates a degree of degradation of at least one cell of the controllable unit.

96. The at least one non-transitory machine-readable medium of claim 92, further comprising instructions that, when executed, cause the energy storage system to:

the set of BCSs is operated in a charged state or a discharged state, and at least one BCS of the set is also operated simultaneously with the operation of the other BCSs of the set, sometimes in a different state from the other BCSs of the set.