Hybrid energy storage system based on lithium battery energy storage, control method and equipment thereof and medium

Abstract

The invention discloses a hybrid energy storage system based on lithium battery energy storage, a control method and equipment thereof and a medium, and aims to solve the technical problems of slow frequency modulation response, weak peak load processing capability and insufficient system reliability and flexibility in an existing power grid energy storage system. The invention relates to a hybrid energy storage system based on lithium battery energy storage. The hybrid energy storage system comprises a lithium ion battery unit, a supercapacitor unit, a control unit and an energy management system. The control method for the hybrid energy storage system comprises the steps that the power grid load change is monitored through the energy management system, the control unit adjusts the charging and discharging states of the lithium ion battery unit and the super capacitor unit according to the power grid load change, and the current controller and the voltage controller in the control unit work cooperatively to ensure stable operation of the system.

Description

Technical Field

[0001] The present invention relates to the technical field of energy storage and frequency modulation of power systems, and in particular to a hybrid energy storage system based on lithium battery energy storage and a control method, device and medium thereof. Background Art

[0002] In modern power systems, with the widespread access to renewable energy and the growing demand for electricity, higher requirements are placed on the frequency regulation capability, peak load handling capability, and overall reliability and flexibility of the power grid. Lithium-ion batteries have become the preferred technology for grid energy storage due to their high energy density and relatively long cycle life. However, they have limitations in terms of fast response and instantaneous high power output. Supercapacitors make up for this deficiency with their high power density and long cycle life, but when used alone, their energy density is low and cannot meet the needs of long-term energy storage.

[0003] In order to overcome the limitations of single energy storage technology, hybrid energy storage system (HESS) technology has emerged, which combines the advantages of lithium-ion batteries and supercapacitors to achieve the dual goals of long-term energy storage and short-term high power output. This integrated system requires precise control strategies to optimize the charging and discharging process, ensure efficient operation and life extension of the equipment, and maintain the stability of the power grid.

[0004] The development of smart grid technology provides new opportunities for the integration and control of hybrid energy storage systems. Through real-time data collection and analysis, smart grids can better predict and respond to changes in energy demand, thereby making more efficient use of energy storage resources. In addition, government policies and market incentives are also driving the development of energy storage technology to meet the challenges of increased investment in renewable energy, grid modernization needs, and reducing greenhouse gas emissions.

[0005] Nevertheless, hybrid energy storage systems still face technical challenges in practical applications, including how to improve system efficiency, reduce costs, enhance safety and improve system integration capabilities. Summary of the invention

[0006] The purpose of the present invention is to provide a hybrid energy storage system based on lithium battery energy storage and its control method, equipment and medium, so as to overcome the technical problems of slow frequency regulation response, weak peak load processing capacity, insufficient system reliability and flexibility in the existing power grid energy storage system.

[0007] In order to achieve the above object, the present invention adopts the following technical solution:

[0008] A hybrid energy storage system based on lithium battery energy storage, comprising:

[0009] Lithium-ion battery cells, which store and release electrical energy;

[0010] A supercapacitor unit, connected in parallel with the lithium-ion battery unit, is used to provide instantaneous high-power support;

[0011] A control unit connected to the lithium-ion battery unit and the supercapacitor unit, and used to control the charging and discharging operations of the lithium-ion battery unit and the supercapacitor unit;

[0012] An energy management system, connected to the control unit, is used to monitor and optimize the energy flow of the energy storage system.

[0013] Furthermore, the control unit includes a current controller and a voltage controller.

[0014] Furthermore, the energy management system includes a data acquisition module and an energy scheduling module.

[0015] Furthermore, the system also includes a data communication interface for exchanging data with an external system.

[0016] A control method for a hybrid energy storage system based on lithium battery energy storage, the control method is used to control the above hybrid energy storage system, the control method comprises the following steps:

[0017] S1, monitoring grid load changes through energy management system;

[0018] S2, according to the change of grid load, the control unit adjusts the charging and discharging state of the lithium-ion battery unit and the supercapacitor unit;

[0019] S3, the current controller and voltage controller in the control unit work together to ensure stable operation of the system.

[0020] Furthermore, the energy management system also predicts the trend of grid load changes and adjusts the charging and discharging plans based on the prediction results.

[0021] Furthermore, when the system is overloaded, the supercapacitor unit is preferentially used to provide power support.

[0022] Furthermore, lithium-ion battery cells are used to store excess electrical energy when the grid load is low.

[0023] A control device for a hybrid energy storage system based on lithium battery energy storage, comprising:

[0024] Memory for storing computer programs;

[0025] The processor is used to implement the steps of the above-mentioned control method of a hybrid energy storage system based on lithium battery energy storage when executing the computer program.

[0026] A computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the steps of the above-mentioned control method of a hybrid energy storage system based on lithium battery energy storage.

[0027] Compared with the prior art, the present invention has the following beneficial technical effects:

[0028] The present invention provides a hybrid energy storage system based on lithium battery energy storage. By combining lithium-ion batteries and supercapacitors, it can quickly respond to the deviation of the grid frequency, improve the frequency modulation speed and accuracy of the grid, and thus enhance the stability of the grid. The hybrid energy storage system can automatically adjust its charging and discharging strategy under different grid conditions and load changes, providing higher system reliability and operational flexibility.

[0029] The present invention also provides a control method for a hybrid energy storage system based on lithium battery energy storage, which reduces energy loss, lowers operating costs, and extends the service life of the equipment through precise energy management and optimized charging and discharging strategies. Correspondingly, the control device and medium for a hybrid energy storage system based on lithium battery energy storage provided by the present invention also have the above-mentioned beneficial effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 Schematic diagram of a hybrid energy storage system based on lithium battery energy storage in an embodiment of the present invention.

[0031] Figure 2 Schematic diagram of a control method for a hybrid energy storage system based on lithium battery energy storage in an embodiment of the present invention.

[0032] Figure 3 The figure is a schematic diagram of the structure of a control device of a hybrid energy storage system based on lithium battery energy storage in an embodiment of the present invention. DETAILED DESCRIPTION

[0033] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0035] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "provided with", "set / connected", "connected", etc. should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0036] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "several" is two or more, unless otherwise clearly and specifically defined.

[0037] Embodiment 1:

[0038] like Figure 1 The figure shows a hybrid energy storage system based on lithium battery energy storage in an embodiment of the present invention, comprising:

[0039] Lithium-ion battery cells, which store and release electrical energy;

[0040] A supercapacitor unit, connected in parallel with the lithium-ion battery unit, is used to provide instantaneous high-power support;

[0041] A control unit connected to the lithium-ion battery unit and the supercapacitor unit, and used to control the charging and discharging operations of the lithium-ion battery unit and the supercapacitor unit;

[0042] An energy management system, connected to the control unit, is used to monitor and optimize the energy flow of the energy storage system.

[0043] In this embodiment, a hybrid energy storage system based on lithium battery energy storage is used for thermal power units, aiming to improve the competitiveness of thermal power units in the power frequency regulation market, improve frequency regulation performance, and solve the problems of insufficient life and safety of existing lithium battery energy storage frequency regulation projects. The hybrid energy storage system includes the following components:

[0044] Lithium-ion battery unit: configured as 15MW / 7.5MWh (maximum output power 15 megawatts, total stored energy is 7.5 megawatt-hours), can discharge continuously for 5 hours at maximum output power, and can discharge for longer time at lower power, used to store and release electrical energy, meeting the power plant's demand for energy storage in the frequency modulation market.

[0045] Supercapacitor unit: configured as 5MW×4min (the maximum power it can provide is 5 megawatts, and it can discharge continuously for 4 minutes at a rated power of 5MW), connected in parallel with the lithium-ion battery unit to provide high-power output in a short period of time, providing instantaneous high-power support to cope with rapid changes in grid frequency.

[0046] Control unit: connected to the lithium-ion battery unit and the supercapacitor unit, controls the charging and discharging operations of the lithium-ion battery unit and the supercapacitor unit, and ensures that the system responds to the frequency modulation instructions of the power grid.

[0047] Energy management system: connected to the control unit, monitors and optimizes the energy flow of the energy storage system, adjusts the charging and discharging strategy through real-time data analysis and prediction of grid load changes.

[0048] The hybrid energy storage system is packaged in a container and installed outdoors in a reserved space in the power plant. The system is connected to the 6kV bus of the power plant through the PCS (Power Conversion System) step-up and current conversion integrated unit, ensuring compatibility with the existing electrical system of the power plant.

[0049] To ensure the safe operation of the system, the hybrid energy storage system is equipped with a comprehensive protection device and connected to the power plant's DCS (Distributed Control System) system through remote IO (Input / Output) to achieve signal transmission and control command execution. The system also designed an automated RTU (Remote Terminal Unit) telecontrol access method and PMU (Phasor Measurement Unit) access implementation plan to achieve information interaction with the power grid dispatching system and improve the automation level of frequency regulation response.

[0050] In terms of safety verification, the system conducted a detailed analysis, including the frequency regulation power operation range of the energy storage system combined with the unit, analysis of the impact on the power system stabilizer, analysis of the impact on the power flow, verification of the unit's high-speed plant variable capacity, short-circuit current verification, and verification of the impact on power quality, ensuring the safety and reliability of the system under various operating conditions.

[0051] By implementing the hybrid energy storage system, the power plant successfully improved its frequency regulation performance, reduced the power generation plan assessment fee, and increased the AGC (Automatic Generation Control) frequency regulation revenue, which has good economic benefits. At the same time, the implementation of the system verified the feasibility of supercapacitors in the frequency regulation of thermal power units, which has industry demonstration significance and promoted the application and development of energy storage technology in power systems.

[0052] Embodiment 2:

[0053] like Figure 2 The figure shows a control method of a hybrid energy storage system based on lithium battery energy storage in an embodiment of the present invention, and the control method comprises the following steps:

[0054] S1, monitoring grid load changes through energy management system;

[0055] S2, according to the change of grid load, the control unit adjusts the charging and discharging state of the lithium-ion battery unit and the supercapacitor unit;

[0056] S3, the current controller and voltage controller in the control unit work together to ensure stable operation of the system.

[0057] In this embodiment, a control method of a hybrid energy storage system based on lithium battery energy storage is used to control a hybrid energy storage system based on lithium battery energy storage applied to a thermal power unit. The control method specifically includes the following steps:

[0058] S1, Energy Management System (EMS) monitors grid load changes:

[0059] The energy management system EMS monitors key parameters of the power grid in real time, such as frequency deviation and power demand, predicts short-term and long-term demand of the power grid, and provides decision support for the control unit. The energy management system EMS optimizes the charging and discharging strategy of the energy storage system through advanced algorithms and data analysis to adapt to the dynamic changes of the power grid.

[0060] S2, the control unit adjusts the charging and discharging state of the lithium-ion battery unit and the supercapacitor unit:

[0061] The control unit adjusts the charge and discharge status of the lithium-ion battery unit and the supercapacitor unit according to the instructions of the energy management system EMS and the actual needs of the power grid. The control unit also communicates with the distributed control system (DCS) of the power plant to ensure that the operation of the energy storage system is coordinated with the overall control strategy of the power plant.

[0062] S3, the current controller and the voltage controller work together to ensure stable operation of the system:

[0063] The current controller manages the current distribution between the battery cells and the supercapacitor cells, ensuring the reasonable distribution of current under different grid conditions to support the stable operation of the grid.

[0064] The voltage controller maintains the voltage of the battery cell and supercapacitor cell within a safe and efficient range, preventing overcharging or over-discharging and extending the service life of the equipment.

[0065] In addition, the automated RTU (Remote Terminal Unit) telecontrol device and PMU (Phasor Measurement Unit) device are responsible for information exchange with the grid dispatching system and measuring the primary frequency regulation of the hybrid energy storage system, respectively. This enables the grid dispatching to accurately measure and evaluate the contribution of the energy storage system to the grid frequency regulation.

[0066] The hybrid energy storage system participates in the automatic generation control (AGC) frequency regulation, providing the necessary power support to maintain the frequency stability of the power grid by quickly responding to the frequency deviation of the power grid. The system is designed to release or absorb a large amount of power within a few seconds, significantly improving the frequency regulation performance of the power plant.

[0067] In terms of safety protection measures, the system design includes multiple safety protection measures, such as overload protection, short circuit protection, temperature monitoring, etc., to ensure that the power supply can be quickly cut off under abnormal circumstances to protect the safety of equipment and personnel.

[0068] Economic benefit analysis is also a part of the energy management system EMS. It improves the economic performance of the power plant by optimizing the charging and discharging strategies, reducing energy losses, and increasing frequency regulation benefits.

[0069] In summary, the control method of this embodiment can not only ensure the efficient and stable operation of the hybrid energy storage system, but also can be seamlessly integrated with the control system of the power plant and the power grid, provide fast and accurate frequency regulation services, and enhance the stability and reliability of the power grid. At the same time, the economic benefit analysis of the system provides important decision-making support for the power plant, optimizing the use of energy and cost control.

[0070] Embodiment 3:

[0071] like Figure 3 The figure shows a control system of a hybrid energy storage system based on lithium battery energy storage in an embodiment of the present invention, including:

[0072] Memory for storing computer programs;

[0073] The processor is used to implement the steps of the above-mentioned control method of a hybrid energy storage system based on lithium battery energy storage when executing the computer program.

[0074] The computer program includes program instructions. The processor can be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. It is the computing core and control core of the terminal, which is suitable for implementing one or more instructions, specifically suitable for loading and executing one or more instructions to realize the corresponding method flow or corresponding function.

[0075] Embodiment 4:

[0076] In an embodiment of the present invention, a computer-readable storage medium is provided, on which a computer program is stored, and when the computer program is executed by a processor, the steps of the control method of a hybrid energy storage system based on lithium battery energy storage are implemented. Based on such an understanding, the present invention implements all or part of the processes in the above-mentioned embodiment method, and can also be completed by instructing related hardware through a computer program. The computer program can be stored in a computer-readable storage medium, and when the computer program is executed by a processor, the steps of each of the above-mentioned method embodiments can be implemented. Among them, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form. Computer-readable storage media include permanent and non-permanent, removable and non-removable media, and information storage can be implemented by any method or technology. The information can be a computer-readable instruction, a data structure, a module of a program, or other data.

[0077] The computer storage medium can be any available medium or data storage device that can be accessed by a computer, including but not limited to magnetic storage (such as floppy disks, hard disks, magnetic tapes, magneto-optical disks (MO), etc.), optical storage (such as CD, DVD, BD, HVD, etc.), and semiconductor storage (such as ROM, EPROM, EEPROM, non-volatile memory (NANDFLASH), solid-state drive (SSD)), etc.

[0078] The above shows and describes the basic principle of the present invention, the main features and the advantages of the present invention. It should be understood by those skilled in the art that the embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0079] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0080] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0081] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0082] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is defined by the attached claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention. Any figure mark in the claims should not be regarded as limiting the claims involved.

[0083] In addition, it should be understood that although this specification is described in accordance with the implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation modes that can be understood by those skilled in the art. The above content is only to illustrate the technical idea of ​​the present invention, and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution according to the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A hybrid energy storage system based on lithium battery energy storage, characterized in that: include: Lithium-ion battery cells, which store and release electrical energy; A supercapacitor unit, connected in parallel with the lithium-ion battery unit, is used to provide instantaneous high-power support; A control unit, connected to the lithium-ion battery unit and the supercapacitor unit, for controlling the charging and discharging operations of the lithium-ion battery unit and the supercapacitor unit; An energy management system, connected to the control unit, is used to monitor and optimize the energy flow of the energy storage system.

2. A hybrid energy storage system based on lithium battery energy storage according to claim 1, characterized in that: The control unit includes a current controller and a voltage controller.

3. A hybrid energy storage system based on lithium battery energy storage according to claim 1, characterized in that: The energy management system includes a data acquisition module and an energy scheduling module.

4. A hybrid energy storage system based on lithium battery energy storage according to claim 1, characterized in that: The system also includes a data communication interface for exchanging data with an external system.

5. A control method for a hybrid energy storage system based on lithium battery energy storage, characterized in that: The control method is used to control the hybrid energy storage system according to any one of claims 1 to 4, and the control method comprises the following steps: S1, monitoring grid load changes through energy management system; S2, according to the change of grid load, the control unit adjusts the charging and discharging state of the lithium-ion battery unit and the supercapacitor unit; S3, the current controller and voltage controller in the control unit work together to ensure stable operation of the system.

6. A control method for a hybrid energy storage system based on lithium battery energy storage according to claim 5, characterized in that: The energy management system also predicts the trend of grid load changes and adjusts the charging and discharging plans based on the prediction results.

7. The control method of a hybrid energy storage system based on lithium battery energy storage according to claim 5, characterized in that: When the system is overloaded, the supercapacitor unit is used first to provide power support.

8. The control method of a hybrid energy storage system based on lithium battery energy storage according to claim 5, characterized in that: Lithium-ion battery cells are used to store excess electrical energy when grid load is low.

9. A control device for a hybrid energy storage system based on lithium battery energy storage, characterized in that: include: Memory for storing computer programs; A processor is used to implement the steps of a control method for a hybrid energy storage system based on lithium battery energy storage as claimed in claim 5 when executing the computer program.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed by the processor, the steps of the control method of a hybrid energy storage system based on lithium battery energy storage as claimed in claim 5 are implemented.

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