A controller, system, and method of controlling discharge of a heterogeneous battery pack

Abstract

A controller, a system including such a controller, and a method for controlling discharging of a plurality of battery packs are provided. The controller includes one or more processors and at least one tangible, non-transitory machine-readable medium encoded with one or more programs configured to perform steps to determine a respective discharging power or discharging share for each battery pack for maximizing an objective function (J) of the plurality of battery packs defined in equation (1). The controller provides signals with instructions to the plurality of battery packs and / or one or more power converters to discharge from the plurality of battery packs and / or keep a particular battery pack idle based on the respective discharging share and power of the individual battery packs.

Description

[0001] Cross-references to related applications

[0002] This application claims the benefit of U.S. Patent Application No. 17 / 511,806, filed October 27, 2021, the contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure generally relates to systems and methods for controlling battery packs. More specifically, the disclosed subject matter relates to controllers, systems, and methods for controlling the discharge of battery packs, for example, in energy storage applications. Background Technology

[0004] 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 intermittent because they cannot always be dispatched to meet the changing demands 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

[0005] This disclosure provides a controller for controlling the discharge of heterogeneous battery packs, a system including such a controller, such as an energy storage system, and a method for using the controller.

[0006] According to some embodiments, a system includes multiple battery packs, one or more power converters, and one or more controllers. Each power converter is coupled to at least one of the multiple battery packs and configured to convert direct current (DC) from one battery pack to alternating current (AC) or vice versa. The controllers are coupled to the multiple battery packs and the one or more power converters. In some embodiments, the system may also include more than one controller, with each controller coupled to multiple battery packs.

[0007] This document defines and describes multiple battery packs. In some embodiments, the multiple battery packs are heterogeneous battery packs, which may be selected from new batteries, reusable electric vehicle (EV) batteries, or combinations thereof. The multiple battery packs are connected in parallel, in series, or in combinations thereof (i.e., hybrid combinations). In some embodiments, the multiple battery packs are connected in parallel.

[0008] The controller includes one or more processors and at least one tangible, non-transitory machine-readable medium encoded with one or more programs configured to perform steps for controlling the discharge process of the system having the plurality of battery packs. In some embodiments, these steps include: receiving the total power demand (D) that the system needs to be scheduled within a first time interval; collecting characteristic data for each battery pack; and establishing multiple voltage-to-charge curves for each battery pack (i) at multiple discharge rates. Each voltage-to-charge curve corresponds to a specific discharge rate for the corresponding battery pack. The characteristic data for each battery pack includes the maximum voltage (V0) at its respective discharge rate. imax Minimum discharge voltage (V) i min ), maximum discharge (Q) i max ) and minimum discharge (Q i min The characteristic data for each battery pack also includes the maximum total rated power (d). i max ), state of charge (SOC) i ) and current voltage (V i ).

[0009] The steps also include determining the corresponding discharge power (di) or discharge share (w) for each battery pack. i To maximize the objective function (J) of the plurality of battery packs defined in equation (1):

[0010]

[0011] In equation (1), n ​​is the total number of the plurality of battery packs. i * represents the voltage distribution parameters for each battery pack, determined using equation (2):

[0012] V i *=(V i -V i min ) / (V i max -V i min (2)

[0013] It is by (V) i max -V i min ) and (Q i max -Q i min The normalized voltage gradient in the corresponding curve of voltage versus charge, where α is a weighting factor assigned between voltage and voltage gradient in the range of 0 to 1.

[0014] In some embodiments, the controller is configured to determine, through the following steps, the appropriate discharge power (di) or discharge share (w) for each battery pack to maximize the objective function (J) of the plurality of battery packs. i ):

[0015] (a) Assign a first power distribution to each battery pack, including the corresponding first discharge power or discharge share;

[0016] (b) Based on equation (2) based on V at the corresponding discharge rate i max V i min and V i Determine the corresponding voltage distribution parameters (Vi*) for each battery pack;

[0017] (c) Based on the voltage versus charge curves at the respective discharge rates, calculate the corresponding normalized voltage gradient for each battery pack.

[0018] (d) Calculate the objective function (J);

[0019] (e) By assigning a second power distribution, including a corresponding second discharge power or discharge share, to each battery pack, repeat steps (a)-(d) until the objective function (J) is maximized, and the second power distribution differs from the first power distribution; and

[0020] (f) Provide the corresponding discharge power (di) or discharge share (w) to each battery pack. i To maximize the objective function (J) of the plurality of battery packs.

[0021] In some embodiments, the corresponding discharge power or discharge share of each battery pack is assigned or calculated based on either or both of equations (3) and (4):

[0022] and

[0023] d i =w i D (4).

[0024] In some embodiments, the corresponding normalized voltage gradient for each battery pack is calculated according to equation (5).

[0025]

[0026] Where V1, V2, Q1, and Q2 are the voltage and charge at the first and second points of the corresponding voltage-charge curves.

[0027] The step further includes providing signals with instructions to the plurality of battery packs and the one or more power converters, based on the corresponding discharge power (di) or discharge share (w) of each battery pack. i The controller is configured to discharge from the plurality of battery packs and / or keep a particular battery pack idle. The controller is configured to provide signals with instructions to the plurality of battery packs and the one or more power converters. Then, the plurality of battery packs are discharged.

[0028] When the calculated discharge power or share of a particular battery pack is approximately zero, or when such a battery cannot be used to discharge to meet the required conditions due to its voltage being below its minimum voltage for discharge (i.e., experiencing voltage collapse), the particular battery pack remains idle and does not discharge. Such a battery pack may need to be charged or replaced first.

[0029] In some embodiments, the controller is configured to re-determine the corresponding discharge power of each battery pack in a second time interval after the end of the first time interval or when a voltage collapse occurs in the battery pack. In some embodiments, the controller is further configured to dynamically control the discharge of the plurality of battery packs by instantaneously updating the corresponding discharge power or share or discharge rate of each battery pack over time. In some embodiments, the controller is configured to discharge power from the plurality of battery packs to the grid or a load.

[0030] The system may optionally further include one or more battery power management units (BPMUs). Each BPMU may be connected to one or more battery packs and configured to monitor the one or more battery packs and provide characteristic data of the one or more battery packs to the controller.

[0031] In some implementations, the system is an energy storage system. The total power demand is provided by a higher-level energy management system (EMS). In some embodiments, the controller is configured to discharge power from the plurality of battery packs to the grid or a load. In some embodiments, the grid is optional. The power can be released to other components that require power.

[0032] On the other hand, this disclosure provides a controller for controlling the discharge of a system comprising multiple battery packs. As described herein, such a controller includes one or more processors and at least one tangible, non-transitory, machine-readable medium encoded with one or more programs configured to perform the steps described herein. The controller is configured to perform the steps described herein to determine a corresponding discharge power (di) or discharge share (w) for each battery pack. i ), to maximize the objective function (J) of the plurality of battery packs.

[0033] The controller is configured to provide signals with instructions to the plurality of battery packs and the one or more power converters to discharge from the plurality of battery packs and / or keep a particular battery pack idle based on the corresponding discharge power of each battery pack. The controller is also configured to dynamically control the discharge of the plurality of battery packs by instantaneously updating the corresponding discharge share or power of each battery pack over time.

[0034] The controller is configured to couple with a plurality of battery packs that are heterogeneous battery packs selected from new batteries, reusable electric vehicle (EV) batteries, or combinations thereof. The plurality of battery packs are connected in parallel, in series, or in combination thereof. The controller is configured to control the discharge of the heterogeneous battery packs, for example, in an energy storage system. In some embodiments, the controller is configured to optionally discharge power from the plurality of battery packs to the grid or a load.

[0035] On the other hand, this disclosure provides a method for controlling the discharge of a system comprising multiple battery packs via a controller as described herein. The method includes the steps described herein. In this method, the corresponding discharge power (di) or discharge share (w) of each battery pack in a time interval is determined by maximizing an objective function (J) of the multiple battery packs as described above. i ).

[0036] In this method, the controller also provides signals with instructions to the plurality of battery packs and the one or more power converters to discharge from the plurality of battery packs based on a corresponding discharge power of each battery pack and / or to keep a particular battery pack idle as described herein. Discharge from the plurality of battery packs is then performed according to the instructions. In some embodiments, instructions are sent from the controller to each battery pack and / or one or more converters connected to the plurality of battery packs for discharging based on a corresponding discharge power or share of each battery pack.

[0037] The plurality of battery packs are heterogeneous battery packs selected from new batteries, reusable electric vehicle (EV) batteries, or combinations thereof. The plurality of battery packs are connected in parallel, in series, or in combination thereof.

[0038] In some embodiments, some or all of the above steps are repeated to reassign scheduling for the plurality of battery packs after a predetermined time interval has ended or when a voltage collapse occurs in the battery pack. In some embodiments, the discharge process of the plurality of battery packs is dynamically controlled by instantaneously updating the corresponding discharge power or share of each battery pack over time.

[0039] The systems, controllers, and methods provided in this disclosure offer numerous advantages. For example, a variety of new and used battery packs of varying qualities can be used. Pre-selection or removal of battery packs is not required. Multiple heterogeneous battery packs can collectively supply power loads to meet power demands, while each battery pack can discharge at a different share or rate. The systems, controllers, and methods extend the lifespan of each battery pack, and they also provide flexibility in maintaining and upgrading the system. Attached Figure Description

[0040] 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.

[0041] Figure 1 This is a block diagram illustrating an exemplary system including a heterogeneous battery pack and a controller according to some embodiments.

[0042] Figure 2 This is a block diagram illustrating an exemplary controller for controlling the discharge of multiple heterogeneous battery packs according to some embodiments. The exemplary controller includes one or more processors and at least one tangible, non-transitory machine-readable medium encoded with one or more programs.

[0043] Figure 3 The relationship between voltage (V) and charge flow (Ah) of exemplary battery packs in some embodiments is shown.

[0044] Figure 4 This is a flowchart illustrating an exemplary method for controlling the discharge of multiple battery packs according to some embodiments.

[0045] Figure 5 This illustrates, according to some embodiments, methods for determining the corresponding discharge power (di) or discharge share (w) for each battery pack. i The flowchart illustrates an exemplary method for maximizing the objective function (J) of the plurality of battery packs.

[0046] Figures 6A-6B The illustration shows, according to some embodiments, a method for dynamically controlling the battery pack at different time intervals. Figure 6B The general steps of discharge in ) Figure 6A An example program. Detailed Implementation

[0047] 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 the orientation 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 (where structures are directly or indirectly fixed or attached to each other through intermediate structures) and to active or rigid attachments or relationships, unless otherwise explicitly described.

[0048] 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.

[0049] 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 clearly 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. All ranges are inclusive and composable when present. 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, through 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 one of 1, 2, 3, 4, or 5 is negatively excluded; therefore, the statement “1 to 5” can be interpreted as “1 and 3-5, but not 2”, or simply “excluding 2”. “This means that any component, element, property, or step expressly referenced herein may be expressly excluded from the claims, whether such component, element, property, or step is listed as an alternative or whether it is referenced separately.”

[0050] U.S. Patent Application Publication No. 2010 / 0285339A1 discloses a method for charging and discharging an electrochemical battery system, such as a lithium-ion battery system with two battery cells. Battery discharge is determined based on a state of charge (SOC) threshold defined in the system. The criterion for discharging the second battery cell in this system is based on a criterion associated with the first battery cell, rather than its own state. Australian Patent Application No. AU2018236771B2 describes a multi-source distributed energy storage system. However, in this system, two sets of sources cannot be operated at a single time.

[0051] Chinese patent application CN110518667A discloses a parallel battery system for secondary use, comprising a battery module and a DC / DC power converter module. In this battery module, multiple battery packs are connected in parallel, and each battery pack consists of several battery packs connected in series. The battery packs are connected in series to provide similar voltages in the corresponding parallel-connected battery packs. The system utilizes a DC / DC converter and a battery management module within the battery module to control the battery system.

[0052] The system disclosed in CN110518667A ignores the circulating current between new or used batteries and between series-connected battery packs. The disclosed technology limits the scalability of this system to the power grid. A DC-DC converter is an electronic circuit or electromechanical device that converts a direct current (DC) source from one voltage level to another. If the battery system is connected to the power grid, additional AC / DC converters are still required. If a system such as that disclosed in CN110518667A is connected to the power grid, adding more DC / DC converters will significantly increase the total DC current and increase the hardware requirements for the AC / DC converters.

[0053] This disclosure provides a controller for controlling the discharge of heterogeneous battery packs, a system including such a controller, such as an energy storage system, a method of using the controller, and a method for controlling the discharge of a system having multiple battery packs. Multiple battery packs can be discharged simultaneously. The priority and scheduling share or rate of discharge of the multiple battery packs are determined by the methods described herein. This method is used to schedule multiple battery packs with different health conditions to provide a consistent and long-term scheduling distribution. The method relies on optimal discharge management of each battery pack to (A) maintain low charge throughput while maximizing energy output; and (B) reduce stress on the system due to weaker batteries. The managed throughput will result in improved lifespan and performance over the battery's lifetime.

[0054] Power dispatch (discharge) is a function of charge flow and voltage. Dispatched energy is defined as the dispatched power over a user-specified time period. For the same amount of charge flow, higher voltage discharge provides more power compared to lower voltage discharge. Early methods did not consider the influence of voltage on the determination of power or energy dispatch. Furthermore, they did not take into account the voltage of the battery pack and the non-uniformity of the voltage trajectory during discharge.

[0055] This disclosure provides a controller, system, and method for appropriately utilizing heterogeneous batteries, such as new batteries from different manufacturers or repurposed electric vehicle (EV) battery packs, in energy storage applications. Each battery pack operates independently based on its characteristics, such as voltage and voltage gradient. Pre-selection or unpacking is not required.

[0056] One benefit of this invention is the efficient management of battery pack diversity in stationary energy storage applications, such as new batteries, reusable EV battery packs, or combinations thereof. The lifespan of EV battery packs and the overall system lifespan can be extended. This improves the reliability, stability, and safety of the Battery Energy Storage System (BESS).

[0057] The controllers, systems, and methods provided in this disclosure are applicable to different battery packs. These battery packs may have the same or different chemical properties, the same or different performance or degradation, and the same or different physical and / or electrical properties. In some embodiments, the battery pack is a heterogeneous battery pack. As used herein, a “heterogeneous battery pack” refers to a battery pack or module with different capacities, states of charge (SOC), states of health (SOH), and / or voltages, 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 discharged or charged together, while some battery packs may remain idle (not charged or discharged).

[0058] 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 the ideal specifications is 100%. SOH can decrease over time and with use.

[0059] Unless otherwise explicitly stated, the “state of charge” (SOC) as used herein is defined as the charge level of a battery relative to its capacity. SOC is measured in percentage points, with 0% representing empty and 100% representing fully charged.

[0060] 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 human and a machine. An HMI can involve an interface between a human and a machine that has physical input hardware, such as a keyboard, mouse, or any other human-machine 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.

[0061] 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.

[0062] In this disclosure, the terms "power demand," "power dispatch," and "power requirement" are used interchangeably and can refer to the power required for a discharge or charge process. The terms "converter" and "inverter" are used interchangeably. Each battery pack includes an inverter and a battery management unit (BMU) therein. For ease of description, the terms "power inverter" or "AC / DC power converter" are used to describe an internal component within the battery pack, and the terms "power converter" or "power conversion system (PCS)" are used to describe a converter connected to one or more battery packs. The terms "battery management unit (BMU)" or "battery management system (BMS)" are 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.

[0063] In this disclosure, the terms "power" and "energy" are used interchangeably, and energy is described in units of time. Energy and power can be converted over time.

[0064] Unless otherwise expressly stated, the terms “connection” or “coupling” as used herein are understood to encompass different connections or couplings between components for conducting electrical energy or transmitting signals for communication. Such connections or couplings can be made in wired, wireless, or cloud-based modes.

[0065] exist Figure 1-2 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 1-2 The exemplary structures and Figure 3 The data described in the text is plotted or sketched to describe it. Figure 4 The method described in -6.

[0066] refer to Figure 1 The exemplary system 100 includes one or more power converters 10, multiple battery packs 20, and a controller 60. Figure 1The number and configuration of each component listed are for illustrative purposes only. The system can have any suitable number, any suitable combination, or any suitable configuration of each component.

[0067] Each power converter 10 is coupled to at least one of a plurality of battery packs 20 and is configured to convert direct current (DC) from the battery packs to alternating current (AC) or vice versa. The power converter 10 may also be referred to as a power conversion system (PCS) or an inverter.

[0068] The controller 60 is connected to a plurality of battery packs 20 and one or more power converters 10. In some embodiments, the system may also include more than one controller 60, and each controller 60 is coupled to a plurality of battery packs 20.

[0069] The controller 60 may be directly or indirectly coupled to multiple battery packs 20. For example, in some embodiments, the exemplary system 100 may optionally further include one or more battery power management units (BPMUs), which may also be referred to as battery management units (BMUs). Each BPMU 30 may be connected to one or more battery packs 20 and configured to monitor the one or more battery packs 20 and provide characteristic data of the one or more battery packs 20 to the controller 60. In some embodiments, the controller 60 is configured to read data from each battery pack 20. This can be accomplished by each corresponding BPMU 30 connected to each battery pack.

[0070] The plurality of battery packs 20 are heterogeneous battery packs, which may be selected from new batteries, reusable electric vehicle (EV) batteries, or combinations thereof. The plurality of battery packs 20 are connected in parallel, in series, or in combinations thereof (i.e., hybrid combinations). In some embodiments, the plurality of battery packs 20 are connected in parallel. The absence of series connection between the battery packs eliminates cycling current and losses.

[0071] like Figure 1 As shown, 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. The EV batteries used can be directly used in the system without prior selection or removal. Each battery pack 20 includes one or more batteries. Each battery pack 20 may include an internal battery management unit (BMU) and an internal inverter. The EV battery packs 20 are removed from the vehicle and are not disassembled into modules. These EV battery packs 20 can be subjected to simple tests to verify their State of Health (SOH).

[0072] In some embodiments, exemplary system 100 is an energy storage system. The controller 60 is configured to receive a total power demand (D) over a time interval from a higher-level energy management system (EMS) 110. In some embodiments, the controller 60 is configured to discharge power from a plurality of DC battery packs 20 to an AC power grid or load 85. Exemplary system 100 can be used to discharge power from battery packs 20 to the power grid 85, or to charge power from the power grid 85 to battery packs 20. A wire connection 12 may be used. Figure 1 The dashed line 13 in the diagram illustrates an alternative power cable. Multiple power cable topologies can exist between the converter 10 and the battery pack 20. System 100 directly uses the grid-connected AC / DC converter 10, which offers flexibility in size expansion. Grid-connected applications do not require an additional power conversion system.

[0073] In some embodiments, the power grid 85 is optional. The power can be redirected to other components that require electrical power.

[0074] The controller 60 can be connected to other components in wired or wireless mode. Figure 1 In the exemplary system 100 shown, the controller 60 can be connected to other components such as the converter 10, BPMU 30, and EMS 110 via a data cable or wireless connection 22. The BPMU 30 can also be connected to the battery pack 20 via a data cable or wireless connection 22. The controller 60 can operate in a cloud-based mode.

[0075] Each battery pack 20 can be connected to the power converter 10 (or an independent DC port on the converter 10) via a set of automatic DC circuit breakers (not shown), which activate and control the connection between the battery pack 20 and the converter 10. The converter 10 controls whether to charge or discharge the individual EV battery pack 20 by following instructions from the controller 60.

[0076] refer to Figure 2 The controller 60 includes one or more processors 62 and at least one tangible, non-transitory machine-readable medium encoded with one or more programs configured to perform steps as described herein for controlling a discharge process of a system having multiple battery packs. The controller 60, processor 62, and / or program 74 may be external devices to the converter 10 or internal devices within the converter 10.

[0077] The processor(s) 62 may include a central controller 64, which includes a parameter input module 66, a model module 68, a parameter control module 70, and an information and instruction module 72. The parameter input module 66 coordinates with the battery pack 20 (optionally BPMU 30 and HMI or EMS 110) to read data from the battery pack 20 and power requirements from the HMI or EMS 110. The parameter input module 66 also coordinates with each power converter 10. The parameter control module 70 coordinates with each power converter 10 and each battery pack 20, and optionally with BPMU 30 and HMI or EMS 110 to control the discharge process. Together with 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 parameter control module 70 and the information and instruction 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 for presentation to the operator.

[0078] The controller 60 and processor 62, having program 74, are configured to perform discharge or charge steps as described herein. Figure 4 As described in section -6, in some embodiments, the controller 60 is configured to perform the steps described herein. Through these steps as described herein, the corresponding discharge power (di) or discharge share (w) of each battery pack in a time interval is determined by maximizing the objective function (J) of the plurality of battery packs. i ).

[0079] On the other hand, this disclosure provides a controller 60 for controlling the discharge of an exemplary system 100 comprising multiple battery packs 20. As described herein, such a controller 60 includes one or more processors 62 and at least one tangible, non-transitory, machine-readable medium encoded with one or more programs 74 configured to perform the steps described herein. The controller 60 is configured to perform the steps as described herein to determine a corresponding discharge power (di) or discharge share (w) for each battery pack. i ), so as to maximize the objective function (J) of the plurality of battery packs.

[0080] The controller 60 is configured to provide signals with instructions to the plurality of battery packs 20 and the one or more power converters 10 to discharge from the plurality of battery packs 20 and / or keep a particular battery pack idle based on the corresponding discharge power or share of each battery pack 20. The controller 60 is also configured to dynamically control the discharge of the plurality of battery packs 20 by instantaneously updating the corresponding discharge share or power of each battery pack over time.

[0081] The controller 60 is configured such that the plurality of battery packs 20 coupled thereto are heterogeneous battery packs selected from new batteries, reusable electric vehicle (EV) batteries, or combinations thereof. The plurality of battery packs 20 are connected in parallel, in series, or in combination thereof. In some embodiments, the plurality of battery packs 20 are connected in parallel. The controller 60 is configured to control the discharge of the heterogeneous battery packs 20, for example, in an energy storage system. In some embodiments, according to instructions from the controller 60, the required power is discharged from the plurality of battery packs 20 to the grid or load 85.

[0082] Different battery packs (especially second-life or used batteries, or batteries with different capacities and ratings) have varying voltage-charge characteristics. The controller 60 and method in this disclosure bias the discharge to the battery pack with the higher voltage. This ensures higher power dispatch for the same charge throughput, while making it easier to fulfill dispatch commands passed to the battery pack management system. The voltage measured during dispatch can be used to accelerate / delay or stop the discharge.

[0083] refer to Figure 3 This illustrates exemplary voltage versus charge flow curves for an exemplary battery pack 20 during a discharge process at a discharge rate. Input parameters may include voltage, current, and time. Charge or charge flow (Q) is calculated from the current and the elapsed time. The voltage is expressed in volts (V), and the charge flow is expressed in ampere-hours (Ah) or coulombs. Figure 3 As shown, Vmax is the voltage of such a battery pack when it is fully charged or at its maximum permissible charge level. Vmin is the voltage of such a battery pack when it is depleted of charge or reaches its minimum permissible charge level.

[0084] The voltage-to-charge curve can be empirically generated at a constant discharge level, while monitoring the current during the discharge cycle until the voltage drop exceeds a user-defined minimum limit (Vmin), such as... Figure 3 The vertical dashed line in the diagram illustrates this. Current and voltage follow the same or similar trends as charging time increases. In some embodiments, the voltage versus charge curve is empirically generated at a constant discharge level while monitoring the current during the discharge period until the voltage drops beyond a user-defined minimum limit, as shown by the intersection of the vertical dashed line and the horizontal line from the y-axis.

[0085] Different discharge rates can produce different voltage discharge profiles for the same battery pack. A family of profiles with different discharge rates can be provided for each corresponding battery pack 20, and this family of profiles can be used to track the voltage trajectory of the battery pack for a given scheduling event. In some embodiments, techniques such as extrapolation, interpolation, or averaging are used to obtain representative profiles. In a profile, when the voltage drops above Vmin during discharge, the battery pack exhibits a significantly higher voltage gradient and depletes more quickly. This lower limit point can also be referred to as voltage collapse. In some embodiments, Vmax and Vmin are open-circuit voltages specified by the manufacturer or derived from a predetermined voltage-charge profile. The range from Vmin to Vmax can be from 400 volts to 1,000 volts.

[0086] The magnitude of the voltage can be expressed in the form of a normalized voltage, for example, a voltage distribution parameter (V*). The voltage distribution parameter V* of the battery pack 20 having a current voltage (V) is defined as (V - Vmin) / (Vmax - Vmin). The higher this parameter, the greater the extent to which the battery pack can discharge. The voltage distribution parameter V* can be in the range of 0-1 or 0-100% percentage (e.g., in the range of 50-95%).

[0087] The heterogeneous battery pack 20 exhibits varying voltage-charge-time characteristics. For most battery chemistry, healthy batteries exhibit a small voltage drop during normal charge or discharge windows. Therefore, the voltage drop during discharge (e.g., voltage-charge gradient) can be an indicator of health issues. In one embodiment, a method may rely on using the voltage drop during discharge to dynamically assess the health of the battery pack and utilize this voltage-charge gradient to bias scheduling from each battery pack. The algorithm biases discharge to battery packs exhibiting lower voltage-charge gradients. In other words, for all battery packs, the voltage gradient can be minimized. For a battery pack, the voltage-charge gradient (∂V / ∂t) is minimized. i The so-called voltage gradient is defined by equation (6):

[0088]

[0089] Q i Discharge from the i-th battery pack, V i This results in a voltage drop. In some embodiments, the sum of the voltage drops across all battery packs can be minimized. Reduced throughput leads to improved lifespan and performance over the battery's lifetime. Additionally, this ensures better stability of the same charge throughput while making it easier to fulfill scheduling commands passed to the battery pack management system.

[0090] Similar to the normalized voltage or voltage distribution parameter (V*), the charge (Q) can also be normalized relative to the difference between the maximum and minimum charges. The normalized charge can be represented as Q*. The normalized voltage-charge gradient of the battery pack is also called the voltage gradient. Defined in equation (7):

[0091]

[0092] Based on the definitions of V* and Q*, in some implementations, the normalized voltage-charge gradient can be calculated according to the above equation (5):

[0093]

[0094] Where V1, V2, Q1, and Q2 are the voltage and charge at the first and second points of the corresponding voltage-charge curves.

[0095] Gradient of voltage (V) with charge flow (Ah) It can be done To calculate. Higher voltage gradient A higher gradient indicates a deeper impact on battery pack health, while a lower gradient indicates a healthy battery pack. During each iteration, an appropriate gradient is determined while operating near a certain voltage. A higher voltage indicates a higher state of charge (SOC). A lower gradient indicates a discharge process that is beneficial to the long-term health of the battery. Combining these two properties creates an objective function (J) as defined in equation (1). The objective function can be maximized to design a process that correctly balances battery performance and long-term health.

[0096] refer to Figure 4-5 This disclosure also provides a method 200 for controlling the discharge of a system 100 comprising multiple battery packs 20 via a controller 60, as described herein. This method is used to schedule battery packs with different health conditions to provide a consistent and durable scheduling profile. The managed throughput results in improved lifespan and performance throughout the battery pack's service life.

[0097] Figure 4 An exemplary method 200 for discharging a plurality of battery packs 20 in a control system 100 is illustrated according to some embodiments. The plurality of battery packs 20 are heterogeneous battery packs selected from new batteries, reusable electric vehicle (EV) batteries, or combinations thereof. The plurality of battery packs 20 are connected in parallel, in series, or in a combination thereof. The plurality of battery packs 20 are preferably connected in parallel.

[0098] Reference Figure 4In step 202, the total power demand (D) to be scheduled from system 100 in the first time interval is received by controller 60 or calculated by the controller based on information received from EMS 110. As described herein, the total power demand can be received from EMS 110. The time interval can be any period of time, such as 15 minutes.

[0099] In step 204, characteristic data for each battery pack 20 are collected to establish multiple voltage (V) versus charge (Q) curves for each battery pack (i) at multiple discharge rates. Each voltage versus charge curve corresponds to the corresponding discharge rate of the respective battery pack. As described above, Figure 3 An exemplary curve is shown. The voltage-to-charge (amp-hr) characteristic of each battery pack can be obtained empirically or derived for a set of frequently encountered discharge rates. This provides a family of curves that can be used to track the voltage trajectory of the battery packs for a given scheduling event. The plurality of discharge rates can be frequently used discharge rates. The characteristic data for each battery pack includes the maximum voltage (V) at the corresponding discharge rate. i max ), minimum discharge voltage (V) i min ), maximum discharge (Q) i max ) and minimum discharge (Q i min The characteristic data for each battery pack also includes the maximum total rated power (d). imax ), state of charge (SOC) i ) and current voltage (V i ).

[0100] In step 210, the corresponding discharge power (di) or discharge share (w) of each battery pack 20 is determined based on the criterion used to maximize the objective function (J) of the multiple battery packs 20 defined in equation (1). i ):

[0101]

[0102] In equation (1), n ​​is the total number of the multiple battery packs 20 in the system. i * represents the voltage distribution parameters for each battery pack 20, determined using equation (2):

[0103] V i *=(V i -V i min ) / (V i max -V i min (2)

[0104] It is, for example, defined by equation (5) (V) i max -V i min ) and (Q i max -Q i minThe normalized voltage gradient is represented by the normalized voltage versus charge curve, and α is a weighting factor allocated between voltage and voltage gradient in the range of 0 to 1. The weighting factor α can be in any suitable range, for example, from 0.05 to 0.95, and can be predetermined in the method. The weighting factor (α) can be 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or any suitable predetermined number. In some embodiments, the weighting factor (α) can be selected based on the level of service activism. If the desired service is active (i.e., discharging the battery pack to a lower state of charge more frequently, resulting in greater cost savings due to reduced power draw from the grid), the weighting factor (α) can be reduced, for example, making the weighting factor (α) less than 0.5. If a more conservative approach is desired (i.e., discharging the battery pack at a lower frequency to maintain a state of charge (SOC) level, e.g., approximately 50%, and targeting a longer battery life), the weighting factor (α) can be increased, for example, making the weighting factor (α) higher than 0.5. The objective function (J) can be in the range of 0 to 1. In some embodiments, the objective function can preferably be equal to or close to 1, or any possible highest value achievable by using the method on the system, if possible.

[0105] One objective is to develop a method for scheduling multiple battery packs based on optimal voltage and charging characteristics. Battery voltage provides an accurate estimate of the state of charge of a battery pack and its energy supply capability. The voltage gradient reflects battery impedance and should be minimized as much as possible. Battery packs with higher voltage and lower impedance are scheduled to provide more energy compared to lower-voltage battery packs. Open-circuit voltage measurement is a direct method for understanding battery performance along the voltage-charge curve.

[0106] refer to Figure 5 In some embodiments, in step 210, the corresponding discharge power (di) or discharge share (w) of each battery pack for maximizing the objective function (J) of the multiple battery packs is determined. i It can be obtained by a method including steps 212, 214, 216, 218, 220 and 220.

[0107] In step 212, a first power distribution is assigned. This power distribution includes a corresponding first discharge power or discharge share for each battery pack. These are merely initial values ​​for evaluation purposes. The first discharge power or discharge share assigned to each battery pack may correspond to a specific discharge rate and a specific VQ curve for that corresponding battery pack. Accordingly, relevant characteristic data at that corresponding discharge rate can be used.

[0108] In step 214, based on equation (2), based on V at the corresponding discharge ratei max V i min and V i Determine the corresponding voltage distribution parameters (V) for each battery pack 20. i *).

[0109] In some embodiments, the corresponding discharge power or discharge share of each battery pack is assigned or calculated based on either or both of equations (3) and (4):

[0110] as well as

[0111] d i =w i D (4).

[0112] Steps 212 and 214 can be performed simultaneously, or step 212 can be performed after step 214. In some embodiments, equation (3) is used, based on the voltage distribution parameters (Vi*) and maximum total rated power (d) of each battery pack. i max To calculate the first corresponding discharge share (w) of each battery pack. i Based on equation (4), the corresponding power (di) for discharge can be calculated based on the corresponding share and total power demand. The discharge share of a time interval can be converted into the discharge rate.

[0113] In step 216, the corresponding normalized voltage gradient for each battery pack 20 is calculated based on the voltage versus charge curve at the corresponding discharge rate. In some embodiments, the corresponding normalized voltage gradient for each battery pack 20 is calculated according to equation (5).

[0114]

[0115] Where V1, V2, Q1, and Q2 are the voltage and charge at the first and second points of the corresponding voltage-charge curves. Based on the assignments and assumptions made in step 212, the first and second points can be the start and end points of the discharge.

[0116] In step 218, the objective function (J) of the plurality of battery packs is calculated according to equation (1). This is based on the first value of J based on the assignment and assumptions made in step 212.

[0117] In step 220, steps (a), (b), (c), and (d), i.e., steps 212, 214, 216, and 218, are repeated until the objective function (J) is maximized. A second set of power distributions, including a corresponding second discharge power or discharge share for each battery pack, can be assigned. This second set of power distributions differs from the first set of power distributions. A second value of J is calculated.

[0118] By iterating through these steps, the maximum objective function (J) and corresponding conditions can be obtained. If the objective function (J) no longer increases, i.e., it asymptotically approaches or begins to decrease, then maximization has been achieved. Mathematically, the first-order partial derivatives of J with respect to all input variables change sign from +ve to -ve. A maximum threshold cannot be specified for the entire range of battery operation. The maximum value is independent of the optimization algorithm used, such as the steepest gradient and interior points.

[0119] In step 222, the corresponding discharge power (di) or discharge share (w) of each battery pack is provided or output to maximize the objective function (J) of the multiple battery packs. i The data is selected from different sets of power distributions from step 212, but it is a set of power distributions that provides the maximum objective function.

[0120] Return to reference Figure 4 In step 230, the controller 60 provides signals with instructions to the plurality of battery packs 20 and the one or more power converters 10 to discharge from the plurality of battery packs 20 and / or keep a particular battery pack idle based on a corresponding discharge power of each battery pack. In some embodiments, instructions are sent from the controller to each battery pack and / or one or more converters connected to the plurality of battery packs for discharging based on a corresponding discharge share of each battery pack. According to this instruction, power from the plurality of battery packs 20 is discharged.

[0121] When the calculated discharge power or share of a particular battery pack is approximately zero, or when such a battery pack cannot be used to discharge to meet the required conditions (because its voltage is equal to or below its minimum voltage for discharge (i.e., experiencing voltage collapse)), then that particular battery pack remains idle without discharging. Such a battery pack may need to be charged or replaced first.

[0122] Each battery pack's respective discharge share (w) i The discharge power (di) and their respective discharge power can be summarized in a table or graph, which can be shown on display 76.

[0123] For multiple battery packs in the system (a total of n battery packs), the sum of the discharge shares is equal to 1, as shown in equation (7):

[0124]

[0125] During the first time interval, multiple battery packs 20 are discharged to meet the total power demand (D).

[0126] refer to Figure 4In some embodiments, steps 202, 204, 210, and 230 of method 200 can be repeated at a second (next) time interval. The first or second interval can be user-defined. For example, the time interval can be any length from 10 seconds to 2 hours, such as 1 minute, 2 minutes, 5 minutes, 10 minutes, 15 minutes, 30 minutes, or one hour. The controller 60 repeats the process after the time interval ends or when a voltage collapse occurs in the battery pack. Figure 4 and 5 In some or all of the steps, the scheduling (discharge) of the plurality of battery packs is reassigned. In some embodiments, the discharge process of the plurality of battery packs 20 is dynamically controlled by instantaneously updating the corresponding discharge share or power of each battery pack 20 over time. The time interval is minimal.

[0127] As defined in Equation (1), the objective function includes voltage, SOC, and voltage gradient components. Model constraints include the required total scheduling (D) (i.e., the sum of the discharge power of all battery packs), the characteristic curves of each battery pack at different discharge rates, and the maximum scheduling capacity of each battery pack. During implementation, rolling optimization is performed on a backward horizon. The term "horizon" refers to the rolling time period during which the battery pack operates. Figures 6A-6B As shown, rolling optimization can include past time intervals to maximize the objective function at the level (i.e., the window). Figures 6A-6B The following are shown in some embodiments for use at different time intervals ( Figure 6B The general steps for dynamically controlling battery pack discharge in ( ) Figure 6A ). Figures 6A-6B It shows Figure 4-5 The exemplary method described in [the document / document]. Figure 6B In the brackets, each bracket indicates a time interval or time window referred to as a stratum.

[0128] refer to Figure 6A In relation to Figure 4 Step 202 is the same as step 302, to obtain the scheduling level. This scheduling level is the total power demand (D) scheduled from the system within a time interval.

[0129] In step 304, it is with Figure 4 The process is the same as step 204, collecting characteristic data and curves for each battery pack (a total of n battery packs).

[0130] Including Figure 5Step 306 of steps 212, 214, and 216 establishes a normalized variable and equation at a stratum (i.e., the first time interval or time window). For example, the normalized variable includes the corresponding voltage distribution parameter (Vi*) and normalized voltage gradient for each battery pack. These parameters are used to... Figure 5 In step 218, the objective function (J) is calculated.

[0131] In step 308, it is with Figure 4 The same as step 210 in the previous section, and includes at least the following steps: Figure 5 In steps 218 and 220, the objective function is maximized for the first time interval.

[0132] In step 310, a corresponding discharge power or share for each battery pack is assigned to maximize the objective function for the first time interval. The system then discharges accordingly. When the first time window has elapsed, the program moves to the second time interval (i.e., from...). Figure 6B (Move one parenthesis to the next parenthesis). For example... Figure 6A As shown, Figure 6A The steps in the loop are repeated again in another cycle.

[0133] After the controller 60 provides the scheduled power demand for a user-defined time interval (e.g., a first time interval), the converter 10 schedules the battery pack 20 at various power levels within the user-defined time interval. In the event of a voltage collapse or other event, the affected battery pack is removed from the multiple active battery packs. The individual pack scheduling power is determined by the method described above (including maximizing the objective function calculated using equation (1)). In the event of unexpected problems, time correction can also be applied to throttling / acceleration or stopping discharge. Even if the battery pack is large, its scheduled power may be low due to the lower voltage. Conversely, if its voltage is higher, the scheduled energy from smaller batteries may be higher. In any case, the algorithm will ensure that the maximum scheduling capacity (d) of each battery pack is never violated. i,max ).

[0134] In an alternative approach, in step 204, the open-circuit voltage of each battery pack (whether measured or obtained from a calibration curve) can also be used to provide power dispatch. In step 214, in some embodiments, in the event of a significant voltage drop, battery pack-specific time constraints can be used to force certain battery packs to dispatch at a faster / slower rate or to stop discharging. To reduce abrupt changes in the dispatch distribution within the battery pack due to voltage variations, w can be calculated using a window average with formula (8). i Instead of calculating w instantaneously. i :

[0135]

[0136] To reduce fluctuations caused by rapidly shifting voltage curves, window averaging can be applied to calculate the average voltage. Predetermined levels can be used in the optimization formula to prevent short-term fluctuations.

[0137] The systems, controllers, and methods provided in this disclosure offer numerous advantages. For example, various battery packs of different qualities can be used, such as used EV battery packs. Pre-selection or removal of battery packs is not required. If a battery pack and / or a converter fails to respond, the system still has the ability to supply power to the load to meet power demands. The systems, controllers, and methods extend the lifespan of each battery pack, and they also provide flexibility in maintaining and upgrading the system.

[0138] This disclosure also provides at least one tangible, non-transitory machine-readable medium encoded with one or more programs for the controller described above.

[0139] 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 a tangible, non-transient, machine-readable storage medium encoded with computer program code. The medium 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, the 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.

[0140] 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. A system for controlling the discharge of heterogeneous battery packs, comprising: Multiple battery packs; One or more power converters, each power converter being coupled to at least one of the plurality of battery packs and configured to convert DC from one battery pack to AC or vice versa; as well as A controller coupled to the plurality of battery packs and the one or more power converters, the controller including one or more processors and at least one tangible, non-transitory, machine-readable medium encoded with one or more programs configured to perform the following steps: Receive the total power demand D that needs to be scheduled from the system during the first time interval; Characteristic data for each battery pack are collected to establish multiple voltage-to-charge-Q curves for each battery pack i at multiple discharge rates. Each voltage-to-charge curve corresponds to a specific discharge rate for the corresponding battery pack. The characteristic data for each battery pack includes the maximum voltage V at the corresponding discharge rate. i max Minimum discharge voltage V i min Maximum discharge Q i max and minimum discharge Q i min Maximum total rated power d i max State of charge (SOC) i and current voltage V i ; Determine the corresponding discharge power d for each battery pack i or discharge share w i So that the objective function J defined in equation (1) is maximized: (1), in n is the total number of the plurality of battery packs. V i The voltage distribution parameters for each battery pack are determined using equation (2): V i = (V i -V imin ) / (V imax -V imin )(2), It is by (V) i max - V i min ) and (Q i max - Q i min The normalized voltage gradient in the corresponding curve of voltage versus charge, where α is a weighting factor assigned between voltage and voltage gradient in the range of 0 to 1. as well as Provide signals with instructions to the plurality of battery packs and the one or more power converters, based on the corresponding discharge power d of each battery pack. i or discharge share w i Discharge from the plurality of battery packs and / or keep a particular battery pack idle.

2. The system of claim 1, wherein the controller is configured to determine, through the following steps, the corresponding discharge power di or discharge share w for each battery pack that maximizes the objective function J. i : (a) Assign a first power distribution to each battery pack, including the corresponding first discharge power or discharge share; (b) Based on equation (2), based on V at the corresponding discharge rate i max V i min and V i Determine the corresponding voltage distribution parameters Vi for each battery pack. ; (c) Based on the voltage versus charge curves at the respective discharge rates, calculate the corresponding normalized voltage gradient for each battery pack. ; (d) Calculate the objective function J; (e) Repeat steps (a) - (d) until the objective function J is maximized by assigning a second power distribution, including a corresponding second discharge power or discharge share, to each battery pack; and the second power distribution differs from the first power distribution. (f) Provide the corresponding discharge power d for each battery pack i or discharge share w i To maximize the objective function J.

3. The system according to claim 2, wherein, The corresponding discharge power or discharge share of each battery pack is assigned or calculated based on either or both of equations (3) and (4): (3); and (4) Where, d i max The maximum total rated power of the battery pack.

4. The system according to claim 2, wherein, The corresponding normalized voltage gradient for each battery pack Calculated based on equation (5): =(|V1-V2| / |V max -V min |) / (|Q1-Q2| / |Q max -Q min |)(5), Where V1, V2, Q1, and Q2 are the voltage and charge at the first and second points of the corresponding voltage-charge curves.

5. The system according to claim 1, wherein, The plurality of battery packs are selected from the following heterogeneous battery packs: new batteries, reusable electric vehicle (EV) batteries, or combinations thereof, and the plurality of battery packs are connected in parallel, in series, or in combination thereof.

6. The system according to claim 1, further comprising: One or more Battery Power Management Units (BPMUs), each BPMU being connected to one or more battery packs and configured to monitor the one or more battery packs and provide characteristic data of the one or more battery packs to the controller.

7. The system of claim 1, wherein the system is an energy storage system, and the total power demand is provided from a higher-level energy management system.

8. A controller for controlling the discharge of a system comprising multiple battery packs, the controller comprising one or more processors and at least one tangible, non-transitory machine-readable medium encoded with one or more programs configured to perform the following steps: Receive the total power demand D that needs to be scheduled from the system during the first time interval; Characteristic data for each battery pack are collected to establish multiple voltage-to-charge-Q curves for each battery pack i at multiple discharge rates. Each voltage-to-charge curve corresponds to a specific discharge rate for the corresponding battery pack. The characteristic data for each battery pack includes the maximum voltage V at the corresponding discharge rate. i max Minimum discharge voltage V i min Maximum discharge Q i max and minimum discharge Q i min Maximum total rated power d i max State of charge (SOC) i and current voltage V i ; Determine the corresponding discharge power d for each battery pack i or discharge share w i So that the objective function J defined in equation (1) is maximized: (1), in n is the total number of the plurality of battery packs. V i The voltage distribution parameters for each battery pack are determined using equation (2): V i = (V i -V imin ) / (V imax -V imin )(2), It is by (V) i max - V i min ) and (Q i max - Q i min The normalized voltage gradient in the corresponding curve of voltage versus charge, where α is a weighting factor assigned between voltage and voltage gradient in the range of 0 to 1; and Provide signals with instructions to the plurality of battery packs and the one or more power converters, based on the corresponding discharge power d of each battery pack. i or discharge share w i Discharge from the plurality of battery packs and / or keep a particular battery pack idle.

9. The controller of claim 8, wherein the controller is configured to determine, through the following steps, the corresponding discharge power d for maximizing the objective function J of each battery pack. i or discharge share w i : (a) Assign a first power distribution to each battery pack, including the corresponding first discharge power or discharge share; (b) Based on equation (2), based on V at the corresponding discharge rate i max V i min and V i Determine the corresponding voltage distribution parameters Vi for each battery pack. ; (c) Based on the voltage versus charge curves at the respective discharge rates, calculate the corresponding normalized voltage gradient for each battery pack. ; (d) Calculate the objective function J; (e) Repeat steps (a) - (d) until the objective function J is maximized by assigning a second power distribution, including a corresponding second discharge power or discharge share, to each battery pack; and the second power distribution differs from the first power distribution. (f) Provide the corresponding discharge power d for each battery pack i or discharge share w i To maximize the objective function J.

10. The controller according to claim 8, wherein, The plurality of battery packs are selected from the following heterogeneous battery packs: new batteries, reusable electric vehicle (EV) batteries, or combinations thereof, and the plurality of battery packs are connected in parallel, in series, or in combination thereof.

11. The controller according to claim 8, wherein, The controller is configured to repeat the steps to redetermine the corresponding discharge power of each battery pack in a second time interval after the first time interval ends.

12. The controller according to claim 8, wherein, The controller is configured to discharge power from the plurality of battery packs to the grid or load.

13. A method for controlling the discharge of a system comprising multiple battery packs via a controller therein, comprising the steps of: Receive the total power demand D that needs to be scheduled from the system during the first time interval; Characteristic data for each battery pack are collected to establish multiple voltage-to-charge-Q curves for each battery pack i at multiple discharge rates. Each voltage-to-charge curve corresponds to a specific discharge rate for the corresponding battery pack. The characteristic data for each battery pack includes the maximum voltage V at the corresponding discharge rate. i max Minimum discharge voltage V i min Maximum discharge Q i max and minimum discharge Q i min Maximum total rated power d i max State of charge (SOC) i and current voltage V i ; Determine the corresponding discharge power d for each battery pack i or discharge share w i So that the objective function J defined in equation (1) is maximized: (1), in n is the total number of the plurality of battery packs. V i The voltage distribution parameters for each battery pack are determined using equation (2): V i = (V i -V imin ) / (V imax -V imin )(2), It is by (V) i max - V i min ) and (Q i max - Q i min The normalized voltage gradient in the corresponding curve of voltage versus charge, where α is a weighting factor assigned between voltage and voltage gradient in the range of 0 to 1. as well as The plurality of battery packs and one or more power converters are provided with signals having instructions to adjust the discharge power d of each battery pack. i or discharge share w i Discharge from the plurality of battery packs and / or keep a particular battery pack idle.

14. The method according to claim 13, wherein, Determine the corresponding discharge power d for each battery pack i or discharge share w i The steps to maximize the objective function J include the following: (a) Assign a first power distribution to each battery pack, including the corresponding first discharge power or discharge share; (b) Based on equation (2), based on V at the corresponding discharge rate i max V i min and V i Determine the corresponding voltage distribution parameters Vi for each battery pack. ; (c) Based on the voltage versus charge curves at the respective discharge rates, calculate the corresponding normalized voltage gradient for each battery pack. ; (d) Calculate the objective function J; (e) Repeat steps (a) - (d) until the objective function J is maximized by assigning a second power distribution, including a corresponding second discharge power or discharge share, to each battery pack; and the second power distribution differs from the first power distribution. (f) Provide the corresponding discharge power d for each battery pack i or discharge share w i To maximize the objective function J.

15. The method of claim 14, wherein, The corresponding discharge power or discharge share of each battery pack is assigned or calculated based on either or both of equations (3) and (4): (3); and (4) Where, d i max The maximum total rated power of the battery pack.

16. The method of claim 14, wherein, The corresponding normalized voltage gradient for each battery pack Calculated based on equation (5): =(|V1-V2| / |V max -V min |) / (|Q1-Q2| / |Q max -Q min |)(5), Where V1, V2, Q1, and Q2 are the voltage and charge at the first and second points of the corresponding voltage-charge curves.

17. The method according to claim 13, wherein, The plurality of battery packs are selected from the following heterogeneous battery packs: new batteries, reusable electric vehicle (EV) batteries, or combinations thereof, and the plurality of battery packs are connected in parallel, in series, or in combination thereof.

18. The method of claim 13, wherein, When the corresponding discharge power d of a specific battery pack i or discharge share w i Zero or the current voltage V of the battery pack i Below its minimum discharge voltage V i min At that time, the battery pack remains idle.

19. The method according to claim 13, wherein, Power is discharged from the multiple battery packs to the power grid or load.

20. The method of claim 13, further comprising: In a second time interval following the end of the first time interval, the steps are repeated to redetermine the corresponding discharge power of each battery pack.

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