Bmu, energy storage system comprising the bmu, and method of use thereof

Abstract

A battery power management unit (BPMU), an electrical energy storage system comprising one or more such BPMUs, and methods of use thereof are provided. Such a BPMU comprises a microcontroller and one or more processors having at least one tangible non-transitory machine-readable medium encoded with one or more programs. The BPMU is configured to perform the steps of reading data from an internal BMU of a respective battery pack to establish initial values of capacity, energy baseline, state of health (SOH), and state of charge (SOC) of the respective battery pack, checking voltage and current at a time interval, calculating power of the respective battery pack, determining and updating battery data such as SOH and SOC, and transmitting the updated battery data to a system controller for controlling discharge power from or charge power to the respective battery pack.

Description

Technical Field

[0001] This disclosure relates primarily to systems and methods for energy storage. More specifically, the disclosed subject matter relates to battery management units, systems including such battery management units, and methods for monitoring and controlling stationary energy storage. Background Technology

[0002] With increasing concern about environmental issues such as global warming, clean and renewable energy sources have become more important. These energy sources include solar and wind power, as well as rechargeable batteries. Renewable energy sources are inflexible because they cannot be dispatched on demand to meet the ever-changing needs of energy consumers. Energy storage systems are expected to address this flexibility challenge. Stationary energy storage systems can store energy and release it as electricity when needed. Summary of the Invention

[0003] This disclosure provides a battery power management unit (BPMU) for an energy storage system, an energy storage system including such a battery power management unit (BPMU), and a method of using the battery power management unit.

[0004] According to some embodiments, such an energy storage system includes multiple battery packs, one or more battery power management units (BPMUs), one or more power converters, and a system controller. Each battery pack includes an internal battery management unit (BMU). Each BPMU is connected to at least one battery pack. The BPMU includes a microcontroller and one or more processors having at least one tangible, non-transitory, machine-readable medium encoded with one or more programs. The BPMU is configured to perform the following steps: read data from the internal BMU of the respective battery pack to establish initial values ​​for the capacity, energy baseline, and state of charge (SOC) of the respective battery pack; check the voltage and current of the respective battery pack at time intervals; calculate the power of the respective battery pack to incorporate the power into the energy reading of the respective battery pack; and determine and update the state of charge (SOC) of the respective battery pack based on the initial SOC values, the current, and the time intervals. Each power converter is coupled to at least one battery pack and is configured to convert direct current (DC) from the respective battery pack to alternating current (AC) or vice versa. The system controller is used to control the discharge power from or the charging power to the respective battery pack based on updated data including the SOC and energy readings of each respective battery.

[0005] The plurality of battery packs may be heterogeneous battery packs connected in parallel, selected from new batteries, reusable electric vehicle (EV) batteries, or combinations thereof. In some embodiments, the plurality of battery packs are reusable electric vehicle (EV) batteries connected in parallel. The EV batteries used can be directly used in the system without prior selection or removal. Each battery pack includes an inverter and an internal battery management unit (BMU) within the battery pack.

[0006] In some embodiments, each BPMU is also configured to determine the state of health (SOH) of the respective battery pack based on its capacity. Suitable techniques, including but not limited to coulomb counting, electrochemical impedance spectroscopy, any other SOC estimation techniques, or combinations thereof, can be used to determine the SOH and SOC of each respective battery pack. The system controller is configured to control the discharge or charging of each respective battery pack based on its SOH and SOC, as well as power commands from the higher-level energy management system (EMS).

[0007] In some embodiments, each BPMU is also configured to send updated data (e.g., SOH, SOC, and power or energy readings) for each corresponding battery pack to the system controller.

[0008] In some embodiments, each BPMU is also configured to limit the idle time of each corresponding battery pack in order to refresh the internal BMU of that corresponding battery pack.

[0009] In some embodiments, each BPMU also includes at least one CAN reader, a relay chip, and a power supply within the microcontroller. The power supply has a power output that matches the power output of the internal BMU and one or more CAN readers of the corresponding battery.

[0010] In another aspect, this disclosure provides a battery power management unit (BPMU) for an energy storage system. The BPMU includes a microcontroller configured to connect to at least one battery pack, and one or more processors (such as a computer) connected to the microcontroller. The one or more processors have at least one tangible, non-transitory machine-readable medium encoded with one or more programs. The BPMU is configured to perform the following steps: reading data from the internal BMU of the respective battery pack to establish initial values ​​for the capacity, energy baseline, and state of charge (SOC) of the respective battery pack; checking or measuring the voltage and current of the respective battery pack at time intervals; calculating the power of the respective battery pack to incorporate the power into the energy reading of the respective battery pack; and determining and updating the state of charge (SOC) of the respective battery pack based on the initial SOC values, the current, and the time intervals. The BPMU is also configured to send the updated data of the respective battery pack, including the SOC and the energy reading, to a system controller to control the discharge power from or the charging power to the respective battery pack based on the updated data.

[0011] In some embodiments, in systems including one or more BPMUs, the battery pack is a new battery pack as described herein or a reusable electric vehicle (EV) battery pack.

[0012] In some embodiments, the BPMU is further configured to determine the state of health (SOH) of each respective battery pack based on its capacity. Suitable techniques such as coulomb counting, electrochemical impedance spectroscopy, or combinations thereof can be used to determine the SOH and SOC of each respective battery pack. The system controller is configured to control the discharge or charging of each respective battery pack based on its SOH and SOC, as well as power commands from a higher-level energy management system (EMS).

[0013] In some embodiments, the BPMU is also configured to define the idle time for each corresponding battery pack in order to refresh the internal BMU of that corresponding battery pack.

[0014] In some embodiments, each BPMU further includes at least one CAN reader, a relay chip, and a power supply in the microcontroller, the power supply having a power output that matches the power output of the internal BMU of the respective battery and the at least one CAN reader.

[0015] In another aspect, this disclosure provides a method for using a battery power management unit (BPMU) in an energy storage system, or a method for operating said energy storage system. This method includes the following steps performed using the BPMU: reading data from the internal BMU of a respective battery pack among a plurality of battery packs to establish initial values ​​for the capacity, energy baseline, and state of charge (SOC) of that respective battery pack; checking the voltage and current of the respective battery pack at time intervals; calculating the power of the respective battery pack to integrate the power into the energy reading of the respective battery pack; and determining and updating the state of charge (SOC) of the respective battery pack based on the initial values ​​of SOC, the current, and the time intervals. The method may further include transmitting the updated data of the respective battery pack, including the SOC and the energy reading, to a system controller to control the discharge power from or the charging power to the respective battery pack based on the updated data of the respective battery pack.

[0016] As described herein, the plurality of battery packs are heterogeneous battery packs selected from new batteries connected in parallel, secondary electric vehicle (EV) battery packs, or combinations thereof.

[0017] In some embodiments, the method further includes determining the state of health (SOH) of the respective battery pack based on its capacity. The SOH and SOC of each respective battery pack, along with power commands from the higher-level energy management system (EMS), are used by the system controller to control the discharge or charging of each respective battery. Suitable techniques, such as coulomb counting, electrochemical impedance spectroscopy, or any other suitable technique or combination thereof, are used to determine the SOH and SOC of each respective battery pack.

[0018] In some embodiments, the method further includes defining an idle time for each corresponding battery pack in order to refresh the internal BMU of that corresponding battery pack.

[0019] The BPMU, system including the BPMU, and method provided in this disclosure have numerous advantages. For example, the BPMU determines and provides real-time and reliable data on a battery pack that is a reusable EV battery used directly in the system without being removed. This real-time and accurate battery pack data is provided to the system controller for decision-making, such as better controlling the discharge or charging of the battery pack. The lifespan of the battery pack can also be extended through better control. Attached Figure Description

[0020] This disclosure can be best understood from the following detailed description when read in conjunction with the accompanying drawings. It should be emphasized that, by convention, the various features in the drawings are not necessarily drawn to scale. Rather, for clarity, the dimensions of the various features have been arbitrarily enlarged or reduced. Throughout the specification and drawings, the same reference numerals denote the same features.

[0021] Figure 1 This is a block diagram illustrating an exemplary system according to some embodiments, which is a power energy storage system including a battery power management unit (BPMU).

[0022] Figure 2 It shows according to Figure 1 A block diagram of an exemplary system design.

[0023] Figure 3 This is a block diagram illustrating a portion of an exemplary system including a battery power management unit (BPMU) according to some embodiments.

[0024] Figure 4 An exemplary battery pack management unit (BPMU) according to some embodiments is shown.

[0025] Figure 5 This is a block diagram illustrating a portion of an exemplary system including a battery power management unit (BPMU) connected to multiple battery packs, according to some embodiments.

[0026] Figure 6 This is a block diagram illustrating an exemplary BPMU or computer implementation of a unit for managing one or more battery packs according to some embodiments, the unit including one or more processors and at least one tangible, non-transitory machine-readable medium encoded with one or more programs.

[0027] Figure 7 This is a flowchart illustrating an exemplary method for managing one or more battery packs in an energy storage system according to some embodiments.

[0028] Figure 8 This is a flowchart illustrating an exemplary program for managing one or more battery packs according to some embodiments.

[0029] Figure 9 The changes in energy and corresponding voltage over time, read directly from the battery pack's internal BMS, are shown during charge and discharge tests in the control experiment.

[0030] Figure 10 The changes in SOC and corresponding voltage over time, read directly from the internal BMS of the battery pack, are shown during charge and discharge tests in the control experiment.

[0031] Figure 11 The changes in the calculated energy of the battery pack over time at the corresponding voltages during the charge and discharge tests in the experiment are shown.

[0032] Figure 12 The change in SOC of the battery pack over time at the corresponding voltages is shown during the charge and discharge tests in the experiment. Detailed Implementation

[0033] The description of exemplary embodiments is intended to be read in conjunction with the accompanying drawings, which are considered an integral part of the entire written description. In this specification, relative terms such as “lower,” “upper,” “horizontal,” “vertical,” “above,” “below,” “upward,” “downward,” “top,” and “bottom,” and their derivatives (e.g., “horizontally,” “downward,” “upward,” etc.) should be interpreted as referring to orientations as described subsequently or as shown in the drawings discussed. These relative terms are for ease of description and do not require the device to be constructed or operated in a particular orientation. Terms relating to attachment, coupling, etc. (e.g., “connection” and “interconnection”) refer to a relationship in which structures are directly or indirectly fixed or attached to each other through intermediate structures, and to active or rigid connections or relationships, unless otherwise explicitly described.

[0034] For the purposes described below, it should be understood that alternative variations and embodiments may be taken from the examples described below. It should also be understood that the specific articles, compositions, and / or methods described herein are exemplary and should not be considered limiting.

[0035] In this disclosure, the singular forms “a,” “an,” and “the” include plural references, and references to a particular numerical value include at least that particular value unless the context explicitly indicates otherwise. When a value is expressed as an approximation using the antecedent “about,” it should be understood that the particular value forms another embodiment. As used herein, “about X” (where X is a numerical value) preferably refers to ±10% of the referenced value, including the end value. For example, the phrase “about 8” preferably refers to a value of 7.2 to 8.8, including the end value. Where present, all ranges are inclusive and composable. For example, when listing a range of “1 to 5,” the listed range should be interpreted as including the ranges “1 to 4,” “1 to 3,” “1-2 and 4-5,” “1-3 and 5,” “2-5,” etc. Furthermore, when an affirmative list of alternatives is provided, such a list can be interpreted as meaning that any alternative can be excluded, for example, by a negative limitation in the claims. For example, when listing the range “1 to 5”, the listed range can be interpreted to include cases where any of 1, 2, 3, 4, or 5 is negatively excluded; thus, the statement “1 to 5” can be interpreted as “1 and 3-5, but not 2”, or simply “excluding 2”. Any component, element, property, or step expressly referenced herein can be expressly excluded from the claims, whether such component, element, property, or step is listed as an alternative or whether it is referenced separately.

[0036] This disclosure provides a battery power management unit (BPMU) for an energy storage system, an energy storage system including such a battery power management unit (BPMU), and a method of using the battery power management unit.

[0037] Unless otherwise explicitly stated, abbreviations are used in this document. For example, “BESS” refers to Battery Energy Storage System, “BPMU” refers to Battery Pack Management Unit, “SOH” refers to State of Health, and “SOC” refers to State of Charge.

[0038] The controllers, systems, and methods provided in this disclosure are applicable to different battery packs, which are heterogeneous battery packs. As used herein, "heterogeneous battery pack" refers to a battery pack or module with different capacities, SOCs, and / or SOHs, and may be selected from new batteries (e.g., from different manufacturers), repurposed electric vehicle (EV) batteries, or combinations thereof. Repurposed EV batteries are used for illustrative purposes. References to "discharging" or "charging" multiple battery packs are understood to mean that the multiple battery packs are simultaneously discharging or being charged, while some battery packs may remain idle (neither charging nor discharging).

[0039] Unless otherwise explicitly stated, “State of Health (SOH)” as used herein shall be understood as a quality factor comparing the condition of a battery, battery cell, or battery pack to its ideal condition. SOH is expressed as a percentage (%). A condition matching specifications under ideal conditions is 100%. SOH can decrease over time and with use.

[0040] Unless otherwise explicitly stated, the “state of charge” (SOC) as used herein is defined as the level of charge of a battery relative to its capacity. SOC is measured in percentage points, with 0% indicating empty and 100% indicating fully charged.

[0041] The term "Human Machine Interface (HMI)" as used herein is understood to refer to a user interface (UI), the space where interaction occurs between a person and a machine. An HMI can involve the interface between a person and a machine with physical input hardware, such as a keyboard, mouse, or any other human-computer interaction based on touch, vision, or hearing. Such a user interface may include other layers, such as output hardware, like a computer monitor, speakers, and printer.

[0042] As used in this article, the term "Controller Area Network" or "Central Area Network" (CAN) refers to a vehicle bus standard designed to allow microcontroller devices to communicate with each other's applications without a host computer and without wiring each individual component together.

[0043] The term “Transmission Control Protocol / Internet Protocol (TCP / IP)” as used here is understood to be a set of standardized rules that allow computers to communicate on networks such as the Internet.

[0044] As used in this article, “Energy Management System (EMS)” refers to a computer-aided tool system used by operators of a public power grid to monitor, control, and optimize the performance of a power generation or transmission system.

[0045] In this disclosure, the terms "power demand" and "power requirement" are used interchangeably, as are the terms "converter" and "inverter." Each battery pack includes an inverter and a battery management unit (BMU) therein. For ease of description, the term "power inverter" is used to describe an internal component within the battery pack, and the term "power converter" or "power conversion system (PCS)" is used to describe a converter connected to one or more battery packs. The term "battery management unit (BMU)" or "battery management system (BMS)" is used to describe an internal component within the battery pack, and the term "battery power management unit (BPMU)" is used to describe a battery management unit connected to one or more battery packs. The BPMU provided herein may also be referred to as a battery management unit (BMU). The term BPMU is primarily used to distinguish it from the internal BMU within the battery pack.

[0046] Unless otherwise expressly stated, the terms “connection” or “coupling” as used herein are understood to encompass different connections or couplings between components for conducting electricity or transmitting signals for communication. Such connections or couplings can be in wired, wireless, or cloud-based modes.

[0047] Unless explicitly stated otherwise, the reference to "system controller" herein is understood to encompass controllers connected via wired, wireless, or cloud-based technologies, and such controllers are used to control the energy storage system. For example, in some embodiments, such controllers utilize cloud-based and internet-based computing technologies and can perform calculations locally. This technology translates languages ​​from different sources, such as inverter and BMS languages ​​(e.g., CAN, Modbus, DNP3, or any other suitable language). Using this technology, the controller and different devices or units in the system described herein can communicate with each other. Modbus is a data communication protocol and communication protocol standard or a means of connecting industrial electrical equipment.

[0048] exist Figure 1-6 In this context, identical items are represented by the same reference numerals, and for the sake of brevity, the descriptions of the structures provided above with reference to the preceding figures will not be repeated. (See also: [reference]) Figure 1-6 The exemplary structure described in [the document] is used to describe Figure 7 and 8 The method described in [the document / document].

[0049] refer to Figure 1 The diagram illustrates the framework of an exemplary system 100 as an energy storage system. Figure 2 This is an exemplary system 102, which is system 100 in some embodiments. According to some embodiments, such system 100 (or 102) includes a battery power management unit (BPMU) 30.

[0050] Reference Figure 1-2 According to some embodiments, the energy storage system 100 includes multiple battery packs 20, one or more battery power management units (BPMUs) 30, and a system controller 60. The system 100 also includes a power converter 10, also referred to as a power conversion system (PCS). The system controller 60 can be connected to other components in wired or wireless mode. Figure 1 The dashed line 22 in the diagram illustrates that the controller 60 can operate in a cloud-based mode and can also function as a real-time local cloud. System 100 can be used to discharge power from battery pack 20 to the grid 85, or to charge battery pack 20 from the grid 85. A wire connection 12 can be used. Bus 80 may be present between system 100 and the grid 85.

[0051] The plurality of battery packs 20 are connected in parallel configuration 50. In some embodiments, the plurality of battery packs 20 are reusable (i.e., used) electric vehicle (EV) batteries. EV batteries of different capacities can be used directly in the system without prior selection or removal. Figure 1 As shown, each battery pack 20 includes one or more batteries 21, an internal battery management unit (BMU) 25, and an inverter 40. The EV battery pack 20 is removed from the vehicle and is not disassembled into modules.

[0052] Reference Figure 1-2 In some embodiments, system 100 may be directly connected to a power grid 85, which may have a voltage range from 300 volts to 480 volts (e.g., 400–480 volts). In some embodiments, the power grid is a 480V three-phase grid. All components in system 100 (including HMI, converters, BPMU, and protective relays) are linked or coupled to system controller 60 via a TCP / IP network. Controller 60 is networked with all components via TCP / IP 22. User 55 can access the network.

[0053] refer to Figure 2 The exemplary system 102 is an example for illustrative purposes only. System 102 (or 100) may include one or more BPMUs 30. Each BPMU 30 is connected to at least one battery pack 20 and is configured to monitor and control the corresponding battery pack(s) 20(s). Figure 2 For illustrative purposes only, a BPMU 30 and a battery pack 20 are shown. Each power converter 10 is coupled to at least one battery pack 20, for example, via a wire 12. The power converter 10 is configured to convert direct current (DC) from the corresponding battery pack 20 to alternating current (AC) and vice versa.

[0054] System controller 60 is connected, for example, to power converter 10 and BPMU 30 via communication line 22. Battery pack 20, with an internal battery management unit (BMU) 25, is also connected to BPMU 30, and includes a control box with a microcontroller 32 and one or more processors 34. System controller 60 can be connected via wired, wireless, or cloud-based modes. Figure 1 In this configuration, all connections between the controller 60 and other components can be wireless and cloud-based. In some embodiments, connections between other components can be via wires. The power converter 10 controls whether the battery pack 20 is charged or discharged. The controller 60 is configured to adjust the charging / discharging rate based on the condition of the battery pack 20 (e.g., SOC and SOH).

[0055] refer to Figure 2System 102 may also include multiple automatic circuit breakers 14. One or two circuit breakers 14 may be located between the battery pack 20 and the corresponding power converter 10, and are configured to connect or disconnect the corresponding battery pack 20 and the corresponding power converter 10. Circuit breakers 14 may be used between the power converter 10 and the power grid 85. Controller 60 also controls the system's safety by controlling the circuit breaker 14 between the power converter 10 and the battery pack 20. Circuit breaker 14 will protect the corresponding EV battery pack 20 from inrush current and arcing, while also starting the system. Controller 60 collects data from the battery pack 20 and precharges the DC port on the converter 10, then closes the circuit breaker 14 via a functional relay and a switching motor on the circuit breaker.

[0056] Reference Figure 3 The BPMU 30 comprises at least two parts, including a microcontroller 32 in a control box (or relay box) and one or more processors 34 with programs connected to line 12. Each battery pack includes a battery set 27, an internal BMU 25 (or BMS), and an inverter 40. The battery set 27 may include one or more batteries 21 connected to an isolating switch 15, which may include a plunger that is pulled out during transfer. The inverter 40 may include at least two relays, including a main relay 17 and an auxiliary relay 19. The microcontroller 32 is connected, for example, wirelessly to the internal BMS 25 and relays 17 and 19.

[0057] As described herein, the microcontroller 32 is used to activate the internal BMU 25, switch the main battery contacts on / off via relays 17 and 19, and transmit CAN signals between the BPMU 30 and the battery pack 20. The microcontroller 32 in the control box can be a controller such as a Raspberry Pi. The control box may also include relay chips and / or switches, a DC power supply in the range of 5-24 volts (e.g., 12V), and one or more CAN readers. The processor 34 (e.g., a computer) may include one or more programs as described herein to read CAN, classify data, calculate real-time data, convert the data to Modbus, and send the data to the system controller 60. The program may also have the function of pausing the above operations and refreshing the internal BMS. This is considered a battery hibernation period, which occurs at any suitable time, for example, once during a workday.

[0058] The BPMU 30 first activates the battery pack's internal BMS 25 and closes the battery's main contacts. The detailed process may vary depending on the EV battery pack brand. A CAN reader in the control box reads CAN data from the battery pack's internal BMS and sends this data to the processor 34 (e.g., a computer). CAN readers connect to the battery pack's communication ports and read CAN data sequentially. A program in the computer collects the CAN data from the CAN readers and extracts useful information for stationary energy storage applications.

[0059] refer to Figure 4 An exemplary battery pack management unit (BPMU) 30 is shown. The exemplary BPMU 30 includes a microcontroller 32 and a processor 34, such as a personal computer within a housing 36. The microcontroller 32 is connected to and communicates with a corresponding battery pack 20 via a digital I / O interface. Through the microcontroller 32, the BPMU 30 is configured to monitor and control the corresponding battery pack 20 in coordination with a controller 60. The microcontroller 32 and the processor 34 are connected to and communicate with each other. The processor 34 is network-connected to the controller 60.

[0060] refer to Figure 5 The illustration shows a portion of an exemplary system 100 or 102. In such a system, according to some embodiments, a battery power management unit (BPMU) 30 is connected to a plurality of battery packs 20. Figure 5 Five battery packs 20 are shown for illustrative purposes only. Each battery pack includes its own internal BMU. Battery packs 20 are connected to one or more power converters 10 via wired connection 12. The BPMU 30 includes a microcontroller 32 with multiple ports and a CAN reader that connects wirelessly to the battery pack's BMU, for example, via CAN 22a. The BPMU also includes one or more programmable processors 34. The microcontroller 32 can connect and communicate with the processors 34 via Ethernet 22b and a USB adapter 23, such as... Figure 5 As shown. Processor 34 can be wirelessly connected to system controller 60 (e.g., via Ethernet 22b). Figure 5 In this system, multiple CAN readers can be used to read CAN data from multiple battery packs. These CAN readers in microcontroller 32 are connected to processor 34 via USB ports. Appropriate sequences can be created for the connected battery packs. In some embodiments, microcontroller 32 and one or more processors 34 can be a system or a circuit board.

[0061] Reference Figure 1-5This energy storage system 100 (102) includes multiple battery packs 20, one or more battery power management units (BPMUs) 30, one or more power converters 10, and a system controller 60. Each battery pack 20 includes an internal BMU 25 (or BMS). In some embodiments, the multiple battery packs 20 are secondary electric vehicle (EV) batteries connected in parallel. The EV batteries used can be directly used in the system without prior selection or removal. Each battery pack includes an inverter and an internal battery management unit (BMU) within the battery pack.

[0062] Each BPMU 30 is connected to at least one battery pack 20. The BPMU 30 includes a microcontroller 32 in a control box (or relay box) and one or more processors 34 (e.g., a computer) having at least one tangible, non-transitory, machine-readable medium encoded with one or more programs.

[0063] refer to Figure 6 An exemplary BPMU 30 includes one or more processors 62 and at least one tangible, non-transitory machine-readable medium encoded with one or more programs 74, which are executed by the one or more processors 62 and / or microcontroller 32 for managing one or more battery packs according to some embodiments. The processor(s) 62 may include a central battery management unit control 64, which includes a parameter input module 66, a model module 68, a signal control module 70, and an information and instruction output module 72. The parameter input module 66 coordinates with and reads data from the battery pack 20. Together with the one or more programs 74, the model module 68 is configured to perform simulations based on the input parameters to provide information and instructions to the BPMU control module 70 and the information and instruction output module 72. The processor 62 may optionally be connected to one or more displays 76 for displaying information and instructions from the module 72 and the operator.

[0064] The BPMU 30 is configured to perform the steps described herein. These steps include: reading data from the internal BMU 30 of the respective battery pack 20 to establish initial values ​​for the capacity, energy baseline, and state of charge (SOC) of the respective battery pack; checking the voltage and current of the respective battery pack 20 at time intervals; calculating the power of the respective battery pack 20 to incorporate the power into the energy reading of the respective battery pack 20; and determining and updating the state of charge (SOC) of the respective battery pack based on the initial SOC values, the current, and the time intervals. Each power converter 10 is coupled to at least one battery pack and is configured to convert direct current (DC) from the respective battery pack 20 to alternating current (AC), or vice versa. The system controller 60 is used to control the discharge power from or to the respective battery pack 20 based on updated data including the SOC and energy readings of each respective battery.

[0065] In some embodiments, each BPMU 30 is also configured to determine the state of health (SOH) of each respective battery pack 20 based on its capacity. Suitable techniques, including but not limited to coulomb counting, electrochemical impedance spectroscopy, or combinations thereof, may be used to determine the SOH and SOC of each respective battery pack 20. The system controller 60 is configured to control the discharge or charging of each respective battery pack 20 based on its SOH and SOC and power commands from a higher-level energy management system (EMS). Each BPMU 30 is also configured to send updated data (e.g., SOH, SOC, and power or energy readings) of each respective battery pack 20 to the system controller 60.

[0066] In some embodiments, each BPMU 30 is also configured to define an idle time for each corresponding battery pack in order to refresh the internal BMU of the corresponding battery pack. In some embodiments, each BPMU 30 also includes at least one CAN reader, a relay chip, and a power supply in the microcontroller. The power supply has a power output that matches the power output of the internal BMU of the corresponding battery and one or more CAN readers. In some embodiments, the power supply is in the range of 5 volts to 24 volts.

[0067] This disclosure provides a system and method for monitoring and controlling a battery pack 20 that is being withdrawn from an electric vehicle (EV) and planned for use in stationary energy storage applications. The battery pack 20 is used without being disassembled into its individual components. The battery pack 20 includes internal modules, battery cells, and a battery management system (internal BMS) 25 used as is. An external battery management unit (BMU, or BPMU) 30 is developed for one or more battery packs 20 in the EV. The BPMU 30 activates the internal battery management system (BMS) 25, reads CAN data, and filters the data for parameters used to calculate and update key values ​​such as SOC and SOH. This data is then used to determine the operating algorithm for battery usage by the system controller 60.

[0068] In another aspect, this disclosure also provides a battery power management unit (BPMU) 30 for an energy storage system 100 or 102 as described herein. The BPMU 30 includes a microcontroller 32 configured to be connected to at least one battery pack 20, and one or more processors (such as a computer) 34 connected to the microcontroller 32. The one or more processors 34 have at least one tangible, non-transitory machine-readable medium encoded with one or more programs. The battery pack 20 is a reusable electric vehicle (EV) battery pack as described herein.

[0069] The BPMU 30 is configured to perform the following steps: read data from the internal BMU 25 of the respective battery pack 20 to establish initial values ​​for the capacity, energy baseline, and state of charge (SOC) of the respective battery pack 20; check or measure the voltage and current of the respective battery pack 20 at time intervals; calculate the power of the respective battery pack 20 to integrate the power into the energy reading of the respective battery pack; and determine and update the state of charge (SOC) of the respective battery pack 20 based on the initial SOC, the current, and the time intervals. In some embodiments, the BPMU 30 is also configured to determine the state of health (SOH) of each respective battery pack 20 based on the capacity of the respective battery pack 20. Appropriate techniques such as coulomb counting, electrochemical impedance spectroscopy, or combinations thereof can be used to determine the SOH and SOC of each respective battery pack 20. The BPMU 30 is also configured to send updated data of the respective battery pack 20, including the SOC, SOH, and energy readings, to the system controller to control the discharge power from or the charging power to the respective battery pack 20 based on the updated data. The system controller 60 is configured to control the discharge or charging of each respective battery based on the SOH and SOC of each respective battery pack and power commands from the higher-level energy management system (EMS). Furthermore, the BPMU 30 is also configured to define idle times for each respective battery pack to refresh the internal BMU 25 of the respective battery pack 20. In some embodiments, each BPMU 30 also includes at least one CAN reader, a relay chip, and a power supply in the microcontroller 32, the power supply having a power output matching the power output of the internal BMU 25 of the respective battery 20 and at least one CAN reader. A CAN bus is used as an example in this disclosure. The BPMU 30 can work with any other communication protocol such as MODBUS.

[0070] Redundant data from the internal BMS 25 is removed, and non-functional parameters are re-estimated and updated accordingly in the external BPMU 30. The updated parameters are then used by the system controller 60 to make decisions based on algorithms used for battery operation. The BPMU 30 provides real-time and reliable data to the system controller 60, rather than directly using information from the internal BMU 25 of the battery pack 20.

[0071] In some embodiments, the systems and methods provided in this disclosure do not rely on testing methods such as electrochemical impedance spectroscopy (EIS) to determine SOH, but may rely on SOC and SOH values ​​from the internal BMU 25 of the battery pack 20. One objective is to accurately calculate the real-time SOC and SOH values ​​of the secondary-use EV battery pack 20 used in the system.

[0072] An internal BMU (or BMS) 25, originally designed for the vehicle by the original equipment manufacturer (OEM), can be used as a data source for calculating real-time information. The BPMU 30 is also used to make decisions about battery pack operation by transmitting real-time calculation results to the system controller 60. The internal BMU 25 was not designed for stationary energy storage applications, and its functionality is limited after removal from the EV. The BPMU and methods provided herein examine these limitations and improve the real-time calculation of the magic (demonic) values ​​of the battery pack's energy level and state of charge (SOC). The BPMU 30 enhances the functionality of the internal BMU 25 of the battery pack 20 and provides better reference values ​​for system applications. In some embodiments, the BPMU 30 collects data from the internal BMU 25 and verifies accuracy, calculates real-time values ​​of the battery state, updates the data, and transmits the data via TCP / IP in Modbus format. Engineering assumptions are made to approximate the real-time battery state. The BPMU 30 also refreshes the data from the internal BMS at specified time frames to adjust accuracy.

[0073] refer to Figure 7 This document illustrates an exemplary method 200, according to some embodiments, for using a battery power management unit (BPMU) 30 to manage one or more battery packs 20 in an energy storage system 100 or 102, or for operating such a system 100 or 102. According to some embodiments, this method 200 includes the steps of using the BPMU 30 described herein.

[0074] In step 202, data is read from the internal BMU 25 of the respective battery pack 20 among the plurality of battery packs. Initial values ​​for the capacity, energy baseline, and state of charge (SOC) of the respective battery pack 20 are established. As described herein, the plurality of battery packs 20 are selected from new batteries connected in parallel, reusable electric vehicle (EV) battery packs, or combinations thereof. In some embodiments, the state of health (SOH) of each respective battery pack 20 is also determined based on its capacity. Based on this specification, the SOH percentage (%) can be determined by dividing the capacity by the maximum capacity of a brand-new battery pack. SOH can decrease over time and with use. The initial SOC percentage (%) can be determined by dividing the battery's current charge level by its capacity.

[0075] In some embodiments, due to differences in the initial lifespan of the battery pack in EVs or other different applications, the internal BMS 25 of the battery pack 20 may not provide an appropriate reading regarding SOH. Engineering assumptions are made based on the battery pack's history to estimate the SOH. A constant base capacity (the original rated energy of the battery pack) is used in this step.

[0076] In step 204, which may be optional, an idle time (i.e., a sleep cycle) is defined for each corresponding battery pack 20 in order to refresh the internal BMU 25 of the corresponding battery pack 20.

[0077] Stationary applications require the battery pack to always be active. Changes in calculated values ​​(especially energy and SOC) can be significant. The energy baseline must be re-estimated every 24 hours. The BMU simulates the battery pack in a vehicle-off state and activates the internal BMS to update battery parameters. When the battery pack goes into hibernation, a hibernation indication signal is triggered and sent to the upper-level controller to suspend system operation. In BMUs managing multiple battery packs, hibernation is executed sequentially for all battery packs.

[0078] In step 206, the voltage and current of the corresponding battery pack 20 are checked or measured at certain time intervals.

[0079] In step 208, the power of each battery pack 20 is calculated to incorporate this power into the energy reading of the corresponding battery pack 20. Power can be calculated based on voltage and current, and energy can be calculated based on voltage, current, and time. Floating current can be ignored in the calculation.

[0080] In step 210, the state of charge (SOC) of the respective battery pack 20 is determined and updated based on the initial value of SOC, current, and time interval. In some embodiments, suitable techniques such as coulomb counting, electrochemical impedance spectroscopy, or any other suitable technique or combination thereof are used to determine the SOH and SOC of each respective battery pack.

[0081] Coulomb counting is a technique used to track the state of charge (SOC) of a battery pack. It works by integrating the active current flowing over time (in amperes) to derive the sum of energy entering or leaving the battery pack. For example, the SOC of battery pack 20 at any given time can be calculated using the following equation: SOC(t)=SOC(t-Δt)+I(t)*Δt / Qn (1), or

[0082] Where SOC(t) and SOC(t-Δt) are the states of charge of the battery pack at time (t) and (t-Δt), respectively, SOC(t0) is the initial SOC, Δt is the time interval, I(t) is the current of the battery pack, and Qn is the capacity of the battery pack. I(t) can be represented as negative during discharge and positive during charging.

[0083] If the current is recorded as a positive value, then equations (1) and (2) for the discharge process are expressed as follows: SOC(t)=SOC(t-Δt)–I(t)*Δt / Qn (3), and

[0084] For example, in some embodiments, it is assumed that the new EV battery pack has a maximum capacity of 30 kWh rated capacity. After 7-8 years of use in the vehicle, the battery pack is taken out of service at 80% SOH (or lower). The battery pack then has a second life starting with a capacity Qn of 24 kWh, which is equivalent to 30 kWh × 80%. SOC can be estimated using coulomb counting or a similar method. The daily base energy E0 is obtained at the start and / or recovery from dormancy. The energy value is calculated as E = E0 + ΣV*I, and the real-time SOC = E / Qn.

[0085] Steps 202 to 210 can be repeated for each battery pack 20.

[0086] In step 212, updated data for the respective battery pack 20, including its SOC and energy readings, is transmitted to the system controller 60, which controls the discharge power from or the charging power to the respective battery pack 20 based on this updated data. The system controller 60 uses the SOH and SOC of each respective battery 20, along with power commands from a higher-level energy management system (EMS), to control the discharge or charging of each battery. For example, a power allocation rate is calculated for each of a plurality of battery packs 20 connected in parallel. Battery packs 20 with higher capacity and higher SOH and / or SOC are preferably used for discharging to meet power demands from the EMS. An exemplary method of controlling discharge or charging using a system controller is described in the inventors’ co-pending U.S. Application 17 / 201,529.

[0087] refer to Figure 8 Exemplary flowchart 300 is used to illustrate exemplary procedures and methods 200 for managing one or more battery packs according to some embodiments.

[0088] In box 82, the system is started. In box 84, the BPMU 30 activates the internal BMS 25 of the battery pack and closes the main contacts. Detailed procedures may vary depending on the brand of the EV battery pack. In box 86, the CAN reader in the control box reads CAN data from the internal BMS 25 of each battery pack 20 and sends this data to the processor 34. The CAN reader is connected to the communication port of each battery pack 20 and reads CAN data sequentially. A program in the computer collects the CAN data from the CAN reader and extracts useful information for stationary applications. For example... Figure 7As described in step 202, the data is used to establish initial values ​​for the capacity, energy baseline, and state of charge (SOC) of the corresponding battery pack 20. In the program, the energy capacity baseline (i.e., the total operable capacity Qn of the new battery pack) and voltage boundary (Vlow and Vhigh according to the OEM specification) information provided by the battery manufacturer are selected. Baselines, such as energy and SOC values, are determined based on information from the internal BMS 25. Using these baselines, energy and SOC are calculated and updated in real time. Battery pack voltage, average pack temperature, fault codes, and SOH are also collected from the BMS.

[0089] In box 88, a sleep time is defined for each individual battery pack to refresh the internal BMS 25. When this sleep time is set and elapsed, the BPMU 30 returns to read the data again. If no sleep time is set, then in box 90, the voltage and current of each corresponding battery are checked and recorded. During discharge (in... Figure 8 During charging (represented by "i<-1") or charging (represented by "i>1"), the voltage and current at any time will be kept updated by cycling back to box 90. When the corresponding battery is not being charged or discharged, in box 94, the power of the corresponding battery pack 20 is calculated to incorporate that power into the energy reading of the corresponding battery pack 20, such as... Figure 7 As described in step 208. In block 96, based on the initial value of SOC, current, and time interval, the state of charge (SOC) of the corresponding battery pack 20 is determined and updated, as follows. Figure 7 As described in step 210. If, at box 98, the number of repetitions is less than the predetermined maximum number of repetitions (“n_max”), then steps from box 86 to box 96 can be repeated. When the number of repetitions reaches the predetermined maximum number, then at box 103, updated data for the corresponding battery pack 20, including SOC and energy readings, is sent to the system controller 60, for example, via Modbus. Figure 7 As described in step 212. The procedure may terminate at boxes 104 and 106. Otherwise, these steps may be repeated if necessary.

[0090] Due to the potential presence of circulating current, even in idle mode, miscalculations can occur and affect the estimated energy and SOC. In some embodiments, total current less than 1 ampere (i.e., the absolute value of i is less than 1) is ignored, and corresponding limits are set and provided to the upper system controller. The energy and SOC are calculated using voltage and current to better represent the condition of the battery pack.

[0091] Example

[0092] exist Figure 2 In the exemplary system 102, a charge / discharge test is performed, and the results are... Figure 9-12 As shown in the image.

[0093] Figure 9-10 The diagram shows the changes in energy and SOC, along with the corresponding voltage, over time, read directly from the battery pack's internal BMS during charge and discharge tests in a control experiment. These energy and SOC readings are obtained directly from the internal BMS. These values ​​do not accurately represent the battery's state. A sleep / wake-up action was performed at time points following battery discharge and charging.

[0094] Figure 11-12 The diagram shows the changes in the calculated energy and SOC of the battery pack over time at the corresponding voltages during charge and discharge tests in the experiment. Accurate real-time values ​​for battery pack energy and SOC were obtained.

[0095] The BPMU, system including the BPMU, and method provided in this disclosure have numerous advantages. For example, the BPMU determines and provides real-time and reliable data on a battery pack that is a reusable EV battery used directly in the system without being removed. This real-time and accurate battery pack data is provided to the system controller for decision-making, such as better control over the discharge or charging of the battery pack. The lifespan of the battery pack can also be extended through better control.

[0096] The methods and systems described herein can be embodied, at least in part, in the form of computer-implemented processes and apparatus for performing these processes. The disclosed methods can also be embodied, at least in part, in the form of tangible, non-transient machine-readable storage media encoded with computer program code. The media may include, for example, RAM, ROM, CD-ROM, DVD-ROM, BD-ROM, hard disk drive, flash memory, or any other non-transient machine-readable storage medium or any combination of these media, wherein when the computer program code is loaded into and executed by the computer, the computer becomes an apparatus for performing the method. The methods can also be embodied, at least in part, in the form of a computer, in which computer program code is loaded into and / or executed, such that the computer becomes an apparatus for performing the method. When implemented on a general-purpose processor, computer program code segments configure the processor to create specific logic circuits. The methods can optionally be implemented, at least in part, in a digital signal processor formed by an application-specific integrated circuit for performing the methods. The computer or control unit can be operated remotely using a cloud-based system.

[0097] Although the subject matter has been described with reference to exemplary embodiments, it is not limited thereto. Rather, the appended claims should be interpreted broadly to include other variations and embodiments that may be made by those skilled in the art.

Claims

1. An energy storage system, comprising: Multiple battery packs, each including an internal battery management unit (BMU); One or more Battery Power Management Units (BPMUs), each BPMU connected to at least one battery pack, the one or more BPMUs including a microcontroller and one or more processors, the one or more processors having at least one tangible non-transitory machine-readable medium encoded with one or more programs, and configured to perform the following steps: Data is read from the internal BMU of the corresponding battery pack to establish the initial values ​​of the capacity, energy baseline and state of charge (SOC) of the corresponding battery pack; An idle time is defined for each corresponding battery pack in order to refresh the internal BMU of the corresponding battery pack, wherein the idle time is the time during which the battery pack is not charged or discharged; Check the voltage and current of the corresponding battery pack at time intervals; Calculate the power of the corresponding battery pack to integrate the power into the energy reading of the corresponding battery pack; as well as The SOC of the corresponding battery pack is determined and updated based on the initial value of the state of charge (SOC), the current, and the time interval. One or more power converters, each power converter being coupled to at least one battery pack and configured to convert direct current (DC) from the respective battery pack to alternating current (AC) or vice versa; as well as The system controller controls the discharge power from or the charging power to the respective battery pack based on updated data including the SOC and energy readings of each corresponding battery.

2. The system according to claim 1, wherein, The plurality of battery packs are heterogeneous battery packs connected in parallel, selected from new batteries, reusable electric vehicle (EV) batteries, or combinations thereof.

3. The system of claim 1, wherein each BPMU is further configured to determine the state of health (SOH) of the respective battery pack based on the capacity of each respective battery pack.

4. The system according to claim 3, wherein, Techniques including coulomb counting, electrochemical impedance spectroscopy, or combinations thereof are used to determine the SOH and SOC of each corresponding battery pack.

5. The system of claim 3, wherein the system controller is configured to control the discharge or charging of each corresponding battery based on the SOH and SOC of each corresponding battery pack and power commands from the higher-level energy management system (EMS).

6. The system of claim 1, wherein each BPMU is further configured to transmit update data of each corresponding battery pack to the system controller.

7. The system of claim 1, wherein each BPMU further comprises at least one CAN reader, a relay chip, and a power supply in the microcontroller, the power supply having a power output that matches the power output of the internal BMU of the corresponding battery and the at least one CAN reader.

8. A battery power management unit (BPMU) for an energy storage system, comprising: The microcontroller is configured to connect to at least one battery pack; One or more processors, connected to the microcontroller and having at least one tangible, non-transitory machine-readable medium encoded with one or more programs, and the BPMU is configured to perform the following steps: Data is read from the internal BMU of the corresponding battery pack to establish initial values ​​for the capacity, energy baseline, and state of charge (SOC) of the corresponding battery pack; An idle time is defined for each corresponding battery pack in order to refresh the internal BMU of the corresponding battery pack, wherein the idle time is the time during which the battery pack is not charged or discharged; Check the voltage and current of the corresponding battery pack at time intervals; Calculate the power of the corresponding battery pack to integrate the power into the energy reading of the corresponding battery pack; The SOC of the corresponding battery pack is determined and updated based on the initial value of the state of charge (SOC), the current, and the time interval. as well as Updated data of the corresponding battery pack, including the SOC and the energy reading, is transmitted to the system controller to control the discharge power from or the charging power to the corresponding battery pack based on the updated data of the corresponding battery pack.

9. The BPMU of claim 8, wherein the at least one battery pack comprises a heterogeneous battery pack selected from new batteries, secondary electric vehicle (EV) batteries, or combinations thereof.

10. The BPMU of claim 8, wherein the BPMU is further configured to determine the state of health (SOH) of the respective battery pack based on the capacity of each respective battery pack.

11. The BPMU according to claim 10, wherein, Techniques including coulomb counting, electrochemical impedance spectroscopy, or combinations thereof are used to determine the SOH and SOC of each corresponding battery pack.

12. The BPMU of claim 10, wherein the system controller is configured to control the discharge or charging of each respective battery based on the SOH and SOC of each respective battery pack and power commands from the upper-level energy management system (EMS).

13. The BPMU of claim 8, wherein each BPMU further comprises at least one CAN reader, a relay chip, and a power supply in the microcontroller, the power supply having a power output matching the power output of the internal BMU of the respective battery and the at least one CAN reader.

14. A method for using a battery power management unit (BPMU) in an energy storage system, comprising: Data is read from the internal BMU of the corresponding battery pack in multiple battery packs to establish the initial values ​​of the capacity, energy baseline and state of charge (SOC) of the corresponding battery pack; An idle time is defined for each corresponding battery pack in order to refresh the internal BMU of the corresponding battery pack, wherein the idle time is the time during which the battery pack is not charged or discharged; Check the voltage and current of the corresponding battery pack at time intervals; Calculate the power of the corresponding battery pack to integrate the power into the energy reading of the corresponding battery pack; The SOC of the corresponding battery pack is determined and updated based on the initial value of the state of charge (SOC), the current, and the time interval. as well as Updated data of the corresponding battery pack, including the SOC and the energy reading, is transmitted to the system controller to control the discharge power from or the charging power to the corresponding battery pack based on the updated data of the corresponding battery pack.

15. The method according to claim 14, wherein, The plurality of battery packs are heterogeneous battery packs connected in parallel, selected from new batteries, reusable electric vehicle (EV) batteries, or combinations thereof.

16. The method of claim 14, further comprising: The state of health (SOH) of each corresponding battery pack is determined based on its capacity, wherein the SOH and SOC of each corresponding battery pack, as well as power commands from the higher-level energy management system (EMS), are used by the system controller to control the discharge or charging of each corresponding battery.

17. The method according to claim 16, wherein, Techniques including coulomb counting, electrochemical impedance spectroscopy, or combinations thereof are used to determine the SOH and SOC of each corresponding battery pack.

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