Energy storage rolling capacity check including in-situ life model comparison

Abstract

According to some embodiments, a system and method are provided comprising: providing an energy storage device comprising two or more energy storage elements; initiating the execution of an energy storage capacity module that operates to test the capacity of a first energy storage element; removing the first energy storage element from service while maintaining service of the energy storage device; measuring the capacity of the removed first energy storage element; receiving the measured capacity in a ripping model; executing the ripping model to generate an output; and manipulating the operation of the energy storage device based on the generated output. Many other aspects are provided.

Description

Technology Field

[0001] The present invention relates to an energy storage rolling capacity check including in situ life model comparison. Background Technology

[0002] Battery life is generally described as the capacity remaining in a battery at any given time compared to the capacity at the time of new installation or manufacture. Typically, to measure the capacity of batteries used for energy storage in the field, the entire battery system may be taken offline (service interruption), and capacity measurements may be performed separately from the normal operation of the battery system. This standard procedure may take several days, and the operation of industrial processes utilizing these batteries may be suspended during that period. The problem to be solved

[0003] Therefore, it would be desirable to provide a system and method for determining energy storage capacity more efficiently. means of solving the problem

[0004] According to some embodiments, the method comprises: providing an energy storage device comprising two or more energy storage elements; initiating the execution of an energy storage capacity module that operates to test the capacity of a first energy storage element; removing a storage element from service while maintaining service of the energy storage device; measuring the capacity of the removed storage element; receiving the measured capacity in a lifting model; executing the lifting model to generate an output; and manipulating the operation of the energy storage device based on the generated output.

[0005] According to some embodiments, the system comprises: an energy storage device comprising two or more energy storage elements; an energy storage capacity module operating to test the capacity of a first energy storage element; a memory for storing program instructions; and an energy storage processor coupled to the memory, communicating with the energy storage capacity module, and operating to execute program instructions, wherein the program instructions are for initiating the execution of the energy storage capacity module; removing a storage element from service while maintaining service of the energy storage device; measuring the capacity of the removed storage element; receiving the measured capacity from a ripping model; executing the ripping model to generate an output; and manipulating the operation of the energy storage device based on the generated output.

[0006] According to some embodiments, a computer-readable non-transient medium stores instructions that cause a computer processor to perform a method when executed by a computer processor, and the method comprises: initiating the execution of an energy storage capacity module that operates to test the capacity of a first energy storage element of an energy storage device; removing a storage element from service while maintaining service of the energy storage device; measuring the capacity of the removed storage element; receiving the measured capacity in a ripping model; executing the ripping model to generate an output; and manipulating the operation of the energy storage device based on the generated output.

[0007] The technical effect of some embodiments of the present invention is an improved technology and system for checking the energy storage capacity of an element in situ. Some embodiments provide for measuring energy storage capacity while some, rather than all, of the energy storage units are offline, so that most of the energy storage units can be used to supply energy while the capacity check is taking place. Some embodiments provide a more accurate energy storage unit life model, as real-time can be provided to this model and the amount of validation instances can be greater than that of existing life models. Some embodiments can provide for users with increased use of the energy storage unit, as well as any features resulting from increased use (e.g., increased time for revenue generation).

[0008] Together with these and other advantages and features that will become apparent below, a more complete understanding of the essence of the invention can be obtained by referring to the following detailed description and the drawings attached to this specification.

[0009] Other embodiments relate to a system and / or computer-readable medium storing instructions for performing any of the methods described herein. Brief explanation of the drawing

[0010] Figure 1 shows a conventional energy storage unit. FIG. 2 shows a system according to some embodiments. Figure 3 shows a flowchart according to some embodiments. FIG. 4 shows a block diagram of a system according to some embodiments. FIG. 5 shows the discharge of energy between storage elements according to some embodiments. Specific details for implementing the invention

[0011] A battery energy storage system (BESS) is a system that uses battery technology to store energy for later use. A BESS may include multiple battery cells. Some of the battery cells may be grouped together to form a string, and these strings may be grouped together into a rack of one or more battery modules. Racks of battery modules can be connected together and function as a single large battery. Battery cells may degrade in performance over time. Historically, if a BESS owner or operator wanted to determine the capacity of the BESS and the amount of remaining battery life, the operator would need to stop the normal operation of the BESS and perform specialized capacity tests while keeping the entire BESS "offline" (e.g., service interruption). Capacity measurements are typically performed separately from the normal operation of the BESS. Depending on the size of the energy storage site and the number of BESSs to be tested, this conventional procedure could take anywhere from a few days to up to a week. This can be inconvenient because whenever the BESS is not operating normally, the owner of such a site may be unable to provide energy storage services to customers.

[0012] FIG. 1 illustrates a BESS (100) comprising a battery cell (102), a string (104), and a rack (106). Generally, since the capacity of the entire system (100) can be checked simultaneously, the entire BESS (100) is taken "offline" or out of service for testing. As illustrated herein, the shaded battery cell (102) is the cell that is taken offline for testing.

[0013] The embodiments provide a method and system for measuring energy storage unit capacity, wherein a small portion (i.e., some rather than all) of the batteries may be taken offline for measurement, and accordingly, most of the BESS may be in operation while the capacity check is performed.

[0014] Returning to FIGS. 2 and FIGS. 3, a flowchart (300) of examples of a system (200) and an operation according to some embodiments is provided. In particular, FIG. 3 provides a flowchart of a process (300) according to some embodiments. The process (300) and other processes described herein may be performed using any suitable combination of hardware (e.g., circuit(s)), software, or manual means. In one or more embodiments, the system (200) is adjusted to perform the process (300) such that the system is a special purpose element configured to perform operations that cannot be performed by a general-purpose computer or device. Software implementing these processes may be stored on any non-transient type of medium, including a fixed disk, floppy disk, CD, DVD, flash drive, or magnetic tape. Examples of these processes will be described below in relation to embodiments of the system, but the embodiments are not limited thereto.

[0015] Initially, in S310, an energy storage device (202), such as a BESS, is provided. The energy storage device (202) may include two or more energy storage elements, including, but not limited to, a battery (204), a string (206), and a rack (207) of modules ("rack"). In one or more embodiments, the energy storage device (202) may be a battery or any other suitable energy storage device. The energy storage device (202) may be one of a plurality of energy storage devices in a power plant or may be an individual energy storage device. The energy storage devices may provide energy to at least one of a grid, a customer, etc.

[0016] Next, at S312, the operation of the energy storage capacity module (208) is initiated. In one or more embodiments, the energy storage capacity module (208) may operate to test the capacity of the energy storage device (202). The energy storage capacity module (208) may test the capacity of any of any energy storage elements (e.g., batteries, strings, racks, etc.) determined by an operator or any other suitable party. In one or more embodiments, the energy storage capacity module (208) may include one or more processing elements (210) and memory (212). The processor (210) may be, for example, a conventional microprocessor and may operate to control the entire function of the energy storage capacity module (208). In one or more embodiments, the energy storage capacity module (208) may include a processor (210) and a communication controller to allow the energy storage capacity module (208) accordingly to engage in communication via a data network with other devices (e.g., energy storage device (202)) or other user platforms (214). In one or more embodiments, one or more memory and / or data storage devices (212) may include any combination of one or more of a hard disk drive, RAM (random access memory), ROM (read only memory), flash memory, etc. The memory / data storage device (212) may store software that programs the processor (210) and the energy storage capacity module (208) to perform the functions described herein.

[0017] A user / operator may access the system (200) through one of the user platforms (214) (control system, desktop computer, laptop computer, personal digital assistant, tablet, smartphone, etc.) to view information and / or to manage the energy storage device (202) according to any of the embodiments described in this specification.

[0018] In one or more embodiments, the initiation of the operation of the energy storage capacity module (208) may be based on the fulfillment of a capacity check condition. Degradation of the storage element may result from mechanical, chemical, electrochemical, and / or electrochemicalmechanical degradation modes. Each of these modes may be temperature / time dependent. Some non-exclusive examples of capacity check conditions include scheduled checks and event-based checks. In the case of a scheduled check, the energy storage capacity module (208) may be operated to determine the energy storage capacity of the energy storage device (202) at regularly scheduled intervals (e.g., once a month, once every six months, etc.) as determined by an operator or other appropriate party. In the case of an event-based check, the energy storage capacity module (208) may be operated when the battery is unable to maintain as much charge as expected. For example, a model of the BESS system may indicate that a given amount of degradation is expected, and if the BESS begins operation in a manner that does not match the expected amount of degradation, an event-based check may be initiated. An opportunistic check is another non-exclusive example of an event-based check. In one or more embodiments, an opportunistic check may refer to an event or condition that exists when it is easier to measure the capacity of an energy storage device. For example, if the system (200) is scheduled to be idle for 12 hours, this may be a condition where it is easier to measure the device than when the system is not idle, and the check performed at this time may be an opportunistic check. In one or more embodiments, an opportunistic process may be used to predict the timing of the opportunistic check. In one or more embodiments, an opportunistic process may be used to bind elements together with a dynamic balance to ensure that the element under test can be used for a capacity check.As a non-exclusive example, there is an upcoming scheduled discharge event and a group of four elements capable of servicing the discharge event. However, discharging all four elements would provide only 75% discharge for each element, which may not be suitable for a capacity check. An opportunistic process solves this problem by grouping only three of the elements so that the discharge event uses 100% of each element's capacity to cause a successful capacity check.

[0019] Note that capacity check conditions may be changed based on charging conditions. For example, if capacity check conditions are scheduled every 6 months and, based on the most recent capacity check, the energy storage device is degrading faster than expected, the capacity check conditions may be changed to be scheduled every 2 months.

[0020] Returning to process (300), at S314, a storage element is removed from service. As described above, in one or more embodiments, the storage element removed from service is a sub-part of the energy storage device (i.e., a part, not all, of the storage elements of the storage device), while the unremoved part of the energy storage device (202) continues to service. When a storage element is removed from service, the energy storage device may switch to, for example, another power source, or the remainder of the energy storage device may maintain service requirements. For example, as illustrated in FIG. 2, a shaded battery cell (204) is removed from service. The non-exclusive examples described herein have the storage element removed from service as a battery cell, but any other suitable element (e.g., string, rack, etc.) may be removed.

[0021] Next, in S316, the capacity of the removed storage element can be measured by the measurement process (216). In one or more embodiments, to measure the capacity of the removed storage element, the removed storage element may be discharged into one or more available discharge cells (218), indicated by the dotted circle in FIG. 2 and illustrated in FIG. 5. Note that the discharge cells (218) are part of the energy storage device. In one or more embodiments, the discharge cells (218) may be selected by the energy storage capacity module (208). The energy storage capacity module (208) may have a state of available energy measurement for all discharge cells (218). For example, if the discharge cells are in a half voltage range, they may accommodate more than 50% of the energy. The energy storage capacity module (208) determines whether there are enough available discharge cells (218) to accommodate the discharge from the removed storage element.

[0022] For example, note that even if the removed storage element under test is a string, the individual cells constituting the string are discharged. Physically, discharge may occur at the next lowest control level available in the system. For example, if there is cell-level control, capacity per string may be measured, and discharge may occur from the string to the cells. Then, capacity may be measured at the string level, and discharge may occur at the cell level. In one or more embodiments, the unit of capacity is measured as a collection of cells. A collection may have a number of cells greater than one, and a collection having more than one cell may have cells arranged in series, parallel, or a combination thereof, along with at least one set of series cells in the collection. Thus, in one or more embodiments, the capacity of the collection may be measured instead of the cells.

[0023] As a non-exclusive example, if the system contains 100 batteries, the batteries can be organized into strings with 5 parallel batteries, modules of 2 series strings, and racks of 5 series modules. The system can contain 10 modules, which may be the lowest level at which capacity can be measured in this arrangement. Since the racks can have a higher driving voltage than the modules, the racks can be used to charge the modules. Then, because the modules have a higher driving voltage than the strings, the modules can be drained into empty or partially empty strings (discharging batteries).

[0024] Additionally, it should be noted that the removed storage element is not physically removed from the energy storage device, but rather, the removed storage element is electrically disconnected from the energy storage device. After draining, the removed storage element is "effectively empty," that is, it may be empty at a certain minimum reference voltage achievable by the control system. It should be noted that more energy may be discharged from the empty removed storage element by reducing the voltage until the battery does not obtain absolute capacity. However, it may not be necessary to discharge energy from the empty element when the capacity is measured over a defined reference voltage range and, as described by one or more embodiments, the capacity changes over time. As a non-exclusive example, there may be five available discharge cells to accommodate the energy drained from the removed storage element. When energy from the removed storage element is discharged to the discharge cells, the discharged Amps (energy) is measured. Capacity may be measured as the amount of energy discharged from the collection elements over a defined voltage range. For example, to measure the actual capacity, a fixed constant current load of X amperes is applied, and a clock is activated. The current flowing in by the load is measured (measured as X ampere current). The voltage on the battery is continuously measured, and when the end of the discharge voltage is reached, the clock stops at time T. The constant current value of X amperes multiplied by the measured time T will result in a measured capacity (219) of X x T. After discharge, the available discharge batteries can be filled. Then, the filled discharge batteries (218) return energy to the removed storage element to push the removed storage element to full charge.A collection of cells (e.g., removed storage elements and discharged cells) can be used to determine the capacity of the removed storage element, but note that there may be net zero energy transfer from the energy storage device, excluding transfer between cells and efficiency losses.

[0025] Next, in S318, the measured capacity (219) is received from the ripping model (220), and the removed storage element is returned to service in S320. Note that the sequence of S318 and S320 may occur simultaneously, substantially simultaneously, or at different times.

[0026] The lifing model (220) may be, as a non-limiting example, a degeneration / lifetime model that calculates any one of the expected degeneration / expected capacity / total failure time or expected number of failure cycles for a specific energy storage element based on one or more input parameters, including temperature-based acceleration, voltage-based acceleration, and throughput-based acceleration. In one or more embodiments, the lifing model (220) may be a digital twin that may be unique to the removed storage element. One or more embodiments may also provide a global lifing model (222), as further described below.

[0027] The rip model (220) may be executed in S322. The executed rip model (220) may output the expected degeneration (224) for the removed storage element. In one or more embodiments, initial parameters may be supplied to the rip model (220) by a developer or other suitable party. Following S322, the rip model (220) may be updated with parameters from the capacity measured in S324. Updating the rip model (220) may provide a continuous learning system that provides current energy storage device estimates. In one or more embodiments, the rip model (220) may be asset-specific.

[0028] Next, the expected degradation (224) from the ripping model (220) can be compared with the measured capacity (219) of the storage element removed in S326. In one or more embodiments, the energy storage capacity module (208) can determine whether the difference between the expected degradation (224) and the measured capacity (219) is within a threshold value.

[0029] Next, the operation of the energy storage device (202) can be operated in S328. In one or more embodiments, this operation may be based on a comparison with a threshold value. Based on the results of the in-situ life model calculation, the operator of the energy storage system may change the operation of the energy storage device. For example, they may use the energy storage device more because there is more life remaining than they thought (and, for example, because they will be able to earn more money), or they may use it less because there is less life remaining than they thought, and they want the battery to last until the expected end of its original life.

[0030] In one or more embodiments, after the removed energy storage element is returned to service in S320, the next or second energy storage element from the energy storage device (202) may be removed from service for capacity measurement as described above in relation to S322 through S326. Note that in one or more embodiments, this process of checking the next energy storage elements may continue until all energy storage elements within the energy storage device are tested, or until some other user-defined stop criteria are met. Then, before the operation of the energy storage device (202) in S328, the energy storage capacity module (208) in S330 may determine a degradation estimate for the energy storage device by analyzing the distribution of measured capacities across two or more energy storage elements (202) by executing a global leeping model (222) (e.g., a leeping / digital twin model of the energy storage device). In one or more embodiments, the global lying model may provide an average degradation rate and a standard deviation for comparing individual energy storage elements forming an energy storage device.

[0031] In one or more embodiments, reliability may be used to trigger additional measurements. As described above, the system may include a global leeching model, and capacity checks may be received from energy storage elements forming an energy storage device to update the global leeching model. When predictions made by the global leeching model begin to drift from previous predictions, the energy storage capacity module (208) may determine the likelihood of an output from the current model given the output of the previous model. If the outputs are likely to be identical, the model may receive a high reliability. If the outputs are unlikely to be identical (e.g., below a threshold value), the model may receive a low reliability, which may indicate that the model has drifted. When the model has drifted, the drift data may be reported to the user via the user platform (214), and the user may then decide to perform capacity checks on individual energy storage elements to determine the cause of the drift. In one or more embodiments, when the model drifts, the energy storage capacity module (208) can automatically perform capacity checks on individual energy storage elements (e.g., under non-scheduled conditions) to determine the cause of the drift.

[0032] In one or more embodiments, a global leeching model and reliability for an energy storage device may be used to determine the interval for testing the capacity of energy storage elements. For example, if the reliability of the global leeching model is high in predicting the degradation of the energy storage element, less frequent capacity checks may be scheduled. As a non-exclusive example, if the reliability in the model is greater than 85%, the user does not need to schedule capacity checks and instead may rely on non-scheduled capacity checks (e.g., event-based checks). As another non-exclusive example, if the measured capacity exceeds the predicted degradation capacity, non-scheduled capacity check verification (e.g., event-based checks) may be executed instead of scheduling capacity checks. For example, if the reliability of the global leeching model is low in predicting the degrading capacity or if the storage device may be close to a failure point, more frequent capacity checks may be scheduled.

[0033] Next, the process (300) may return to S328 to manipulate the operation of the energy storage device. In one or more embodiments, the energy storage capacity module (208) may analyze the distribution to determine whether the measured capacity for an individual energy storage element is based on randomness within the system or is distorted by some other element. As a non-exclusive example, if one energy storage element is located in a sunny spot and another energy storage element is located in a shaded spot, the energy storage element located in the sunny spot may degrade faster than the energy storage element located in the shaded spot. In this way, the energy storage capacity module (208) may shift the operation of the energy storage device to create a longer lifespan for the device in a process that may be referred to as "load balancing" (e.g., using fewer elements that degrade faster and more elements that degrade slower).

[0034] It should be noted that the embodiments described herein may be implemented using any number of different hardware configurations. For example, FIG. 4 illustrates an energy capacity processing platform (400) that may be associated with, for example, the system (200) of FIG. 2. The energy storage processing platform (400) includes an energy capacity processor (410) ("processor"), such as one or more commercially available central processing units (CPUs) in the form of one-chip microprocessors, coupled to a communication device (420) configured to communicate through a communication network (not shown in FIG. 4). The communication device (420) may be used, for example, to communicate with one or more users. The energy capacity processing platform (400) further includes an input device (440) (e.g., a mouse and / or keyboard for inputting information regarding measurements and / or assets) and an output device (450) (e.g., for outputting and displaying data and / or recommendations).

[0035] The processor (410) also communicates with a memory / storage device (430). The storage device (430) may include any suitable information storage device, including combinations of magnetic storage devices (e.g., hard disk drives), optical storage devices, mobile phones, and / or semiconductor memory devices. The storage device (430) may store a program (412) and / or energy capacity processing logic (414) for controlling the processor (410). The processor (410) executes the instructions of the programs (412, 414) and accordingly operates according to any of the embodiments described herein. For example, the processor (410) may determine the capacity of an energy storage element to operate the energy storage device.

[0036] The programs (412, 414) may be stored in a compressed format, an uncompiled format, and / or an encrypted format. The programs (412, 414) may further include other program elements, such as an operating system, a database management system, and / or a device driver, which are used by the processor (410) to interface with peripheral devices.

[0037] As used herein, information may be "received" or "transmitted" by, for example, the following: (i) a platform (400) of another device; or (ii) another software application, module, or a software application or module within the platform (400) from any other source.

[0038] As will be known to those skilled in the art, embodiments of the present invention may be implemented as a system, a method, or a computer program product. Accordingly, embodiments of the present invention may take the form of a complete hardware embodiment, a complete software embodiment (including firmware, resident software, microcode, etc.), or an embodiment combining software and hardware embodiments, which may all be collectively referred to as "circuit," "module," or "system" in this specification. Additionally, embodiments of the present invention may take the form of a computer program product comprising computer-readable program code contained in one or more computer-readable media(s).

[0039] The flowcharts and block diagrams in the drawings illustrate the structure, function, and operation of potential embodiments of systems, methods, and computer program products according to various embodiments of the present invention. In this regard, each block in the flowcharts or block diagrams may represent a module, segment, or part of code containing one or more executable instructions for performing a specified logical function(s). Additionally, it should be noted that in some alternative embodiments, the functions mentioned in the blocks may occur out of the order mentioned in the drawings. For example, depending on the related functions, two blocks depicted consecutively may, in practice, be executed substantially simultaneously, or the blocks may sometimes be executed in the reverse order. Additionally, it should be noted that each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, may be implemented by a special-purpose hardware-based system that performs the specified function or operation, or by a combination of special-purpose hardware and computer instructions.

[0040] Any of the methods described herein may include an additional step of providing a system comprising individual software modules implemented on a computer-readable storage medium; it should be noted that the modules may include, for example, all or any of the elements illustrated in the block diagrams and described herein and / or, as a non-limiting example, a geometric compensation module. Then, the method steps may be performed using individual software modules and / or sub-modules of the system, which are executed on one or more hardware processors (410) (Fig. 4) as described above. Additionally, the computer program product may include a computer-readable storage medium having code configured to be implemented to perform one or more method steps described herein, including providing a system having individual software modules.

[0041] The description provided here discloses the invention, including preferred embodiments, and uses examples to enable those skilled in the art to practice the invention, including manufacturing and using any device or system and performing any integrated method. The patentable scope of the invention is defined by the claims and may include other examples that may arise to those skilled in the art. These other examples are intended to be within the scope of the claims if they have structural elements that are not different from the literal language of the claims, or if they include equivalent structural elements that differ substantially from the literal language of the claims. Aspects from the various described embodiments, as well as other known equivalents for each such embodiment, may be mixed and matched by those skilled in the art to construct additional embodiments and techniques in accordance with the principles of this application.

[0042] Those skilled in the art will recognize that various adaptations and modifications of the foregoing embodiments may be made without departing from the scope and spirit of the claims. Accordingly, it should be understood that the claims may be practiced differently from as specifically described herein.

Claims

Claim 1 A method comprising: providing an energy storage device (202) comprising two or more energy storage elements (204, 206, 207); initiating the execution of an energy storage capacity module (208) that operates to test the capacity of a first energy storage element; removing the first energy storage element from service while maintaining service of the energy storage device; measuring the capacity (219) of the removed first energy storage element; receiving the measured capacity in a lifting model (220); executing the lifting model to generate an output; and operating the energy storage device based on the generated output, wherein the step of measuring the capacity of the removed first energy storage element comprises discharging energy from the removed first energy storage element to another energy storage element (218) within the energy storage device, and determining the capacity of the removed first energy storage element based on a measured load current and a measured discharge time during discharge.

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