Battery energy storage system for rapid frequency modulation and control method thereof

Abstract

The invention relates to the technical field of safety control of an electric power energy storage system, and discloses a battery energy storage system for fast frequency modulation and a control method thereof, and the system comprises a distributed power buffer module array which is used for absorbing or releasing a high-frequency fluctuation component in a power instruction from a power grid dispatching end; a subarea countercurrent liquid cooling subsystem, wherein a cooling loop of each liquid cooling subarea adopts a countercurrent arrangement mode; and the global energy router is used for selecting part of the battery clusters to execute the power instruction according to the power instruction and the state of each power buffer module, and synchronously adjusting the cooling intensity of the corresponding liquid cooling partition. According to the method, external millisecond-level power impact is converted into gentle thermal load and periodic stress relaxation in the battery through triple defense lines, so that the problem of local thermal runaway of the electric energy storage system in a rapid frequency modulation scene is solved, and the safety and durability of the electric energy storage system in long-term and high-strength rapid frequency modulation service are ensured.

Description

Technical Field

[0001] This invention relates to the field of safety control technology for power energy storage systems, and in particular to a battery energy storage system for fast frequency regulation and its control method. Background Technology

[0002] With the increasing penetration of renewable energy and the growing demand for rapidly adjustable resources in the power system, large-scale containerized lithium-ion battery energy storage systems have become core equipment for providing services such as time-of-use electricity arbitrage, grid peak shaving and frequency regulation, and emergency backup power. For example, such systems can typically be integrated into a standard 20-foot container, which contains a large number of battery clusters. The container employs thermal insulation design to maintain environmental stability and relies on a highly efficient liquid-cooled air conditioning system, such as a three-stage liquid cooling pipeline, to precisely control the cell operating temperature within the ideal range of 20-30°C to ensure its cycle life and safety.

[0003] In actual operation, to stabilize the grid frequency, energy storage systems need to participate in highly demanding ancillary services such as primary frequency regulation. For example, when the grid experiences a sudden frequency drop of approximately 0.2Hz due to a large generator unit tripping, the grid dispatch center will issue a power command requiring the energy storage power station to immediately switch from a near-fully charged standby state to maximum power discharge within hundreds of milliseconds to support the grid frequency. This scenario exposes the fundamental limitations of traditional battery thermal management systems: the battery's heat generation rate can change drastically with current at the millisecond level, while liquid cooling systems relying on high-inertia circulating working fluids have significant second-level delays in temperature and flow regulation. This severe mismatch between rapid electrical heating and slow thermal cooling causes the battery to endure high-frequency alternating thermal stress. The direct consequence is that, under long-term operation, the microscopic interface between the electrode material and the current collector will peel off due to fatigue, and the thermal interface between the cell and the liquid cooling plate will crack due to stress. The former will cause irreversible growth in internal resistance and local overheating, while the latter will directly lead to heat dissipation failure. The combination of the two will cause the risk of local thermal runaway to rise sharply when the battery is dealing with subsequent power surges, posing a serious threat to the safety of highly integrated containerized energy storage systems.

[0004] Current technologies primarily rely on reactive thermal protection strategies in battery management systems, i.e., derating power or increasing cooling intensity after detecting excessive battery temperature or temperature difference. However, this "damage first, remedy later" approach has inherent drawbacks: First, temperature sensors typically monitor macroscopic average or local point temperatures, failing to detect mechanical fatigue accumulated at the microscopic interfaces of materials due to rapid temperature fluctuations; second, the response is hysteretic, unable to prevent thermal shock; and third, simple global derating sacrifices system regulation performance and benefits. Although some research has attempted predictive control through complex thermal models, these methods are computationally intensive, rely on precise parameters, and lack robustness in real-world operating environments, making reliable online applications difficult in integrated controllers of containerized energy storage systems.

[0005] Therefore, the industry urgently needs an innovative system architecture and control method that can fundamentally decouple the instantaneous power demand of the power grid from the thermal shock experienced by the battery itself, and ensure the safety and durability of the power storage system in long-term, high-intensity, high-frequency regulation service without sacrificing rapid response capabilities. Summary of the Invention

[0006] To address the above problems, the present invention provides the following technical solution:

[0007] In a first aspect, the present invention discloses a battery energy storage system for fast frequency regulation, comprising a battery cluster array, a high-voltage box, and a power converter, the system comprising:

[0008] The distributed power buffer module array is set up one-to-one with the battery clusters in the battery cluster array and electrically connected between the corresponding battery cluster and the high-voltage box. It is used to absorb or release high-frequency fluctuation components in the power command from the power grid dispatching terminal.

[0009] The partitioned counter-current liquid cooling subsystem includes a liquid cooling partition set up independently for each battery cluster. The cooling circuit of each liquid cooling partition adopts a counter-current arrangement with the inlet located at the top of the battery cluster and the outlet located at the bottom of the battery cluster.

[0010] The global energy router is connected to the distributed power buffer module array and the partitioned counter-current liquid cooling subsystem. It is used to select some battery clusters as service units to execute power commands according to the power command and the status of each power buffer module, and synchronously adjust the cooling intensity of the corresponding liquid cooling partition.

[0011] Furthermore, the distributed power buffer module is a flywheel-supercapacitor composite module, which includes a flywheel energy storage unit and a supercapacitor unit that are physically coaxially connected.

[0012] Furthermore, the global energy router assesses the real-time available capacity of each power buffer module based on the rotational speed of the flywheel energy storage unit or the voltage status of the supercapacitor unit.

[0013] Furthermore, the cooling circuits of each liquid cooling zone are connected in series through pipelines, so that the coolant inlet of the liquid cooling zone far from the high-pressure box is connected to the coolant outlet of the liquid cooling zone adjacent to the high-pressure box, thereby forming a coolant temperature gradient field in the arrangement direction of the battery cluster array.

[0014] Furthermore, the battery cluster array is pre-divided into at least two logical groups; the global energy router is configured to: control one logical group as a service unit when responding to a power command, control the remaining logical groups to be in a hot recovery state, and periodically or according to the state trigger the rotation between logical groups.

[0015] Furthermore, the global energy router prioritizes logical packets with high available capacity of the corresponding power buffer module and low inlet temperature of the corresponding liquid-cooled partition as service units.

[0016] Furthermore, when triggering logical group rotation, the global energy router dynamically adjusts the thermal recovery time of the logical group to which each battery cluster belongs, based on the historical cumulative discharge depth or the highest temperature experienced in history.

[0017] Furthermore, the global energy router is configured to: upon receiving a power command from the power grid dispatching terminal, decompose the corresponding frequency band in the power command into high-frequency components and low-frequency components, and prioritize allocating the high-frequency components to be buffered by the distributed power buffer module array.

[0018] Secondly, this invention discloses a control method for fast frequency regulation, used to implement the aforementioned battery energy storage system for fast frequency regulation. The method is executed by a global energy router and includes the following steps:

[0019] Receive real-time power commands from the power grid dispatching terminal;

[0020] Obtain the available capacity status of each distributed power buffer module and the cooling status of each liquid cooling zone;

[0021] Based on available capacity status and cooling status, a subset of all battery clusters is selected as the currently serving cluster;

[0022] Distribute real-time power commands to the distributed power buffer modules corresponding to the currently serving clusters;

[0023] Synchronously adjust the cooling intensity of the liquid cooling zone corresponding to the currently serving cluster.

[0024] Furthermore, the steps for selecting the currently serving cluster based on available capacity and cooling status include:

[0025] Divide the battery clusters into at least two logical groups;

[0026] Calculate the comprehensive status score of each logical group. The comprehensive status score is positively correlated with the available capacity of the power module corresponding to each battery cluster in the group, and negatively correlated with the inlet temperature of the liquid cooling zone corresponding to each battery cluster.

[0027] The logical group with the highest overall status score is selected as the currently serving cluster.

[0028] Compared with related technologies, the present invention has the following beneficial effects:

[0029] This invention constructs a distributed power buffer module array to form the first active defense line in the electrical path, decoupling the drastically changing high-frequency components in the power command from the grid dispatching terminal from the DC current flowing to the battery cluster. Through physical buffering, the rate of change of current experienced by the battery tends to be smooth, thereby suppressing the severe internal heat fluctuations caused by millisecond-level current drastic changes at the source. The partitioned counter-current liquid cooling subsystem constitutes the second heat conduction defense line, which is precisely matched with the grid. Through topology reconstruction, the distribution logic of the cooling medium is spontaneously matched with the spatial distribution of the system's heat load. The counter-current design improves the heat dissipation uniformity of a single cluster, and the temperature gradient field formed by series connection realizes the on-demand allocation of cooling capacity, ensuring that the heat generated by the battery can be efficiently and uniformly discharged, avoiding heat accumulation and local overheating caused by delayed or uneven heat dissipation. The global energy router, as the system brain, forms the third intelligent scheduling defense line. By integrating electrical buffer capacity and heat dissipation status information in real time, it dynamically selects the optimal working unit and simultaneously enhances its cooling, while arranging a controlled heat recovery period for other units. From the perspective of system operation strategy, it breaks the vicious cycle of continuous electrothermal stress accumulation and fatigue damage. Through the seamless connection and closed-loop operation of these three defense lines, the millisecond-level power surges from the outside are transformed into a smooth thermal load and periodic stress relaxation inside the battery. This solves the problem of local thermal runaway in the power storage system under rapid frequency regulation scenarios, and ensures the safety and durability of the power storage system in long-term, high-intensity rapid frequency regulation service.

[0030] This invention introduces a power buffer module combining a flywheel and a supercapacitor. The flywheel, with its enormous rotational inertia, handles power shortages or excesses lasting several seconds, while the supercapacitor absorbs transient power spikes with a millisecond-level response speed. The two are physically coaxially coupled to form a hybrid power system with complementary response characteristics. This completely decouples the battery cluster from the high-frequency power fluctuations on the grid side, ensuring that it always operates under a gently changing current condition. This eliminates the physical conditions that cause peeling forces between active material particles and current collectors due to rapid current changes inside the battery, thus improving the efficiency of full-band decomposition and processing of grid power commands.

[0031] This invention implements a dynamic grouping and rotation scheduling strategy based on real-time electrothermal state fusion assessment through a global energy router. The battery cluster array is divided into logical groups and assigned alternating states of service and thermal recovery. By calculating the comprehensive state score of each group in real time and always prioritizing the group with the highest score to undertake power tasks, while ensuring that the remaining groups obtain a full thermal recovery time, this mechanism actively creates a periodic thermal stress relaxation window at the system level. This allows the battery to effectively restore its microstructural stability after experiencing electrochemical and thermal loads, thereby breaking the chain of continuous and irreversible fatigue damage accumulation in traditional operation. Attached Figure Description

[0032] Figure 1 A schematic diagram illustrating the working process of a battery energy storage system for rapid frequency regulation provided by the present invention;

[0033] Figure 2 This is a flowchart illustrating the steps of a control method for fast frequency modulation provided by the present invention. Detailed Implementation

[0034] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] This embodiment provides a battery energy storage system for fast frequency regulation, including a battery cluster array, a high-voltage box, a power converter, a distributed power buffer module array, a partitioned counterflow liquid cooling subsystem, and a global energy router.

[0036] The battery energy storage system can be integrated into a standard 20-foot container as a containerized lithium-ion battery energy storage system. The container's interior features an insulated and sealed design to provide a stable operating environment for the internal equipment. The core energy storage unit of the system is a battery cluster array, which can consist of 12 independent battery clusters arranged vertically. Each battery cluster is further integrated with 4 battery packs. The cells can use lithium iron phosphate material, with a single cell capacity of 280 Ah to 314 Ah, and a total system capacity of 5 MWh.

[0037] A high-voltage box can be centrally located at one end of the container. This box integrates DC buses, fuses, contactors, and other power distribution and protection devices, enabling the collection, distribution, and electrical isolation of power from all battery clusters. This centralized arrangement facilitates maintenance. Adjacent to the high-voltage box is a power converter. Its DC side is connected to the high-voltage box, and its AC side is connected to the power grid. The power converter is responsible for bidirectional energy conversion between DC and AC, executing charging and discharging power commands from the power grid dispatch center.

[0038] The system can be equipped with a liquid-cooled air conditioner, which can provide forced cooling to the battery cluster array through a three-stage liquid cooling pipeline, with the goal of maintaining the battery operating temperature between 20 and 30 degrees Celsius.

[0039] In this embodiment, the distributed power buffer module array is configured one-to-one with the battery clusters in the battery cluster array, and is electrically connected between the corresponding battery cluster and the high-voltage box, for absorbing or releasing high-frequency fluctuation components in the power commands from the grid dispatching terminal. The distributed power buffer module can be a flywheel-supercapacitor composite module, which includes a flywheel energy storage unit and a supercapacitor unit that are physically coaxially connected.

[0040] The flywheel energy storage unit, as a mechanical energy storage device, consists at its core a composite material rotor that rotates at high speed, suspended by magnetic bearings within a vacuum chamber. The stored energy (kinetic energy) is proportional to the square of the rotational speed, expressed as: ,in Energy storage capacity (joules). The moment of inertia of the rotor is (kg·m²). The value is angular velocity (rad / s). This unit is characterized by high power density and extremely long cycle life, making it suitable for handling power fluctuations lasting from several seconds to tens of seconds. Supercapacitor units, also known as electric double-layer capacitors, store charge by forming an electric double layer at the electrode-electrolyte interface. They are characterized by extremely high power density, millisecond-level charge / discharge response time, and over one million cycles, making them suitable for handling high-frequency, transient power spikes.

[0041] In this embodiment, the motor or generator rotor of the flywheel energy storage unit and the motor and generator rotor of the supercapacitor unit can be rigidly connected through the same mechanical shaft, forming a unified electromechanical energy converter. This enables seamless collaboration between the two, achieving direct and efficient coupling of the mechanical and electrical forms of energy.

[0042] Specifically, an independent flywheel-supercapacitor composite power buffer module can be connected in series between the DC positive and negative buses of each battery cluster and the containerized high-voltage centralized distribution box. This module can be located electricalally between the battery cluster and the high-voltage box, forming a series path of battery cluster—buffer module—high-voltage box. During stable periods when the grid does not issue severe power commands, the battery cluster supplies power to this composite module with a small DC current, which is the normal operation (floating charging) phase. This current drives its internal motor, maintaining the flywheel rotor at a preset rated speed, for example, corresponding to 80% of its maximum energy storage, while simultaneously charging the supercapacitor to its rated voltage. At this time, the module acts as a stable load and does not draw fluctuating power from the battery cluster.

[0043] Please see Figure 1 As shown, in the dynamic response (buffering) phase, when the power grid dispatching terminal issues a power command that causes a dramatic change in the power converter's demand within milliseconds, the command first acts on the composite power buffer module. Specifically, when the command requires instantaneous discharge, the module controls its motor to operate as a generator. The flywheel's huge rotational inertia causes its speed to decrease gradually, releasing the stored kinetic energy. Simultaneously, the supercapacitor provides transient peak current through rapid discharge. These two mechanisms work together to prioritize the response to the high-frequency fluctuations and initial high current demand in the command. When the command requires instantaneous charging, the process is reversed: the module absorbs the instantaneous high-power pulse and converts it into the kinetic energy of the flywheel acceleration and the charge of the supercapacitor.

[0044] In this embodiment, the global energy router can assess the real-time available capacity of each power buffer module based on the rotational speed of the flywheel energy storage unit or the voltage status of the supercapacitor unit. Specifically, the flywheel rotational speed can be acquired by a high-precision optical encoder mounted on the flywheel shaft, which is used to calculate the real-time energy storage capacity of the supercapacitor. The core parameters, among which This is the nominal capacitance value. The terminal voltage is used; the module's input and output currents can be acquired by Hall current sensors to monitor and evaluate its instantaneous power throughput and efficiency.

[0045] This implementation combines a flywheel and a supercapacitor, achieving complementary advantages across frequency bands. The flywheel excels at handling low-frequency, high-inertia continuous power components, while the supercapacitor excels at handling high-frequency, rapid transient power spikes. The combination covers the entire frequency range of grid power commands, from sub-second to minute-level fluctuations, ensuring smooth battery current under all conditions. Furthermore, the battery cluster operates under smooth DC conditions, with a gradual change in its internal heat generation rate, fundamentally eliminating the conditions that cause alternating thermal stress on electrode materials due to drastic current changes. This significantly suppresses fatigue damage to the battery's microstructure, reduces the risk of thermal runaway, and thus significantly extends the overall service life of the system.

[0046] In this embodiment, the partitioned counter-current liquid cooling subsystem includes a liquid cooling partition independently set up for each battery cluster. The cooling circuit of each liquid cooling partition adopts a counter-current arrangement with the inlet located at the top of the battery cluster and the outlet located at the bottom of the battery cluster. Furthermore, the cooling circuits of each liquid cooling partition can be connected in series through pipelines, so that the coolant inlet of the liquid cooling partition far from the high-voltage box is connected to the coolant outlet of the liquid cooling partition adjacent to the high-voltage box, thereby forming a coolant temperature gradient field in the arrangement direction of the battery cluster array.

[0047] The liquid-cooled zone refers to a cooling unit that is independently set up for each individual battery cluster, with a relatively independent fluid and control system. Each zone has its own independent inlet pipe, outlet pipe, and flow control valve, thereby achieving precise thermal management for individual battery clusters.

[0048] Since the high-voltage boxes are centrally located at one end of the container, and the battery clusters are arranged longitudinally along the length of the container, the liquid cooling zone adjacent to the high-voltage box specifically refers to the liquid cooling zone serving the first battery cluster that is physically closest to the high-voltage box. Correspondingly, the liquid cooling zone farther from the high-voltage box refers to the liquid cooling zone serving subsequent battery clusters that are further away from the high-voltage box along the length of the container. The phrase "its coolant inlet connects to the coolant outlet of the liquid cooling zone adjacent to the high-voltage box" means that, according to the physical installation sequence of the battery clusters from closest to farthest from the high-voltage box, the outlet pipe of the liquid cooling zone of the previous battery cluster is used as the inlet pipe of the liquid cooling zone of the next battery cluster, thus achieving sequential series connection of the pipes.

[0049] Countercurrent arrangement means that the flow direction of the cooling medium is opposite to the optimal direction of heat transfer. In this system, specifically, the coolant inlet is set at the top of the battery cluster and the outlet is set at the bottom, which is essentially different from the common bottom-inlet and top-outlet (concurrent flow) method; the coolant temperature gradient field means that by connecting the pipelines of each liquid-cooling partition in series, the inlet temperatures of the coolant flowing through different battery clusters show a regular high-low distribution, forming a temperature background field related to the spatial position.

[0050] Specifically, based on the layout of 12 battery clusters arranged longitudinally in the aforementioned standard container, the cooling system is reconstructed in the following manner in this embodiment:

[0051] Partition independence: Cancel the single parallel or series large loop that serves all battery clusters, and configure an independent liquid-cooling micro-partition for each battery cluster. Each partition includes a branch pipe connected from the main distribution pipeline, an electronically controlled regulating valve, a pipeline connected to the internal liquid-cooling plate of the battery cluster module, and a temperature sensor.

[0052] Topological countercurrent: The coolant branch pipe of each partition is connected from the top interface of the battery cluster module, flows through the internal liquid-cooling plate, and then flows out from the bottom interface. This design utilizes the basic principle that hot air rises and cold air descends, enabling the coldest coolant to first contact the upper area with the highest expected temperature in the battery cluster, absorb heat along the way and increase in temperature, and then flow through the lower area with a lower temperature, thereby achieving a more uniform temperature distribution and higher heat transfer efficiency throughout the height of the battery cluster.

[0053] Pipeline series connection and gradient construction: Connect the inlet and outlet pipelines of all 12 independent partitions in series. Specifically, the lowest-temperature coolant output by the liquid-cooling air conditioner unit is first led to the battery cluster partition closest to the high-voltage box and power converter (this area usually has higher additional heat generation due to electrical losses). The high-temperature outlet liquid of this partition is led to the next adjacent battery cluster partition as its inlet liquid, and so on. Finally, a coolant temperature gradient field with a gradually increasing inlet temperature from one end to the other end is naturally formed in the length direction of the container.

[0054] To achieve precise control, the following data needs to be collected in this embodiment: The first is the inlet temperature of the coolant in each partition. This temperature is the key basic data for calculating the heat transfer temperature difference in this partition and evaluating the cooling potential, and this data can be collected by installing a PT100 temperature sensor behind the electronically controlled regulating valve of the inlet pipe of each partition.

[0055] The second is the real-time flow rate of the coolant in each partition. The flow rate data is the direct execution target for controlling the cooling intensity, and this data can be collected by integrating a turbine flowmeter or an ultrasonic flowmeter at or behind the electronically controlled regulating valve of each partition.

[0056] The third key point is battery temperature, which is mainly used to calibrate and verify the cooling effect and as a safety redundancy monitoring. This data can be collected by arranging a small number of thermocouples or digital temperature sensors on representative modules within each battery cluster.

[0057] This embodiment uses a temperature gradient field formed by series connection to preferentially distribute the low-temperature coolant to the area with the heaviest heat generation burden (near the electrical side), achieving spatial matching between cooling resources and heat source distribution. Furthermore, the counter-current arrangement allows the coolant temperature rise process to coordinate with the natural temperature gradient (higher at the top and lower at the bottom) inside the battery cluster. This avoids the problem of insufficient cooling of the upper part caused by the low-temperature coolant cooling the lower part first when arranged in a co-current manner, significantly improving the temperature uniformity of the battery cluster in the vertical direction and reducing local hot spots.

[0058] In this embodiment, the global energy router is communicatively connected to the distributed power buffer module array and the partitioned countercurrent liquid cooling subsystem. It is used to select some battery clusters as service units to execute power commands according to the power command and the status of each power buffer module, and synchronously adjust the cooling intensity of the corresponding liquid cooling partition.

[0059] Furthermore, the battery cluster array is pre-divided into at least two logical groups; the global energy router is configured to: upon responding to a power command, control one logical group as the service unit, control the remaining logical groups to be in a thermal recovery state, and periodically or based on the state trigger rotation between logical groups. The global energy router preferentially selects logical groups with high available capacity of the corresponding power buffer module and low inlet temperature of the corresponding liquid cooling partition as service units. In this embodiment, the 12 physical battery clusters can be virtually grouped at the software level. For example, they can be fixedly divided into 3 groups, each containing 4 consecutively arranged battery clusters. The purpose of grouping is to implement clustered scheduling and management.

[0060] Among them, the global energy router, as the core intelligent control unit, is also an independent hardware controller (such as a high-performance industrial PLC or a dedicated industrial control computer) that runs a dedicated scheduling algorithm. As the central hub connecting the power grid scheduling command, the power buffer module, and the liquid cooling subsystem, it is responsible for decoupling the macro-level power grid demand and transforming it into the optimal collaborative control command for each underlying physical unit. The service unit / service cluster refers to the battery cluster or its group that is selected by the global energy router during a certain period of time and actually undertakes the task of responding to the power grid command. The battery clusters that are not selected are in a thermal recovery state.

[0061] Specifically, the implementation of the global energy router includes three parts: hardware interface, state assessment model, and dynamic scheduling strategy.

[0062] The hardware interface section may include an uplink communication interface, a downlink acquisition interface, and a downlink control interface. The uplink communication interface can receive real-time power commands from the grid dispatching terminal through power-specific protocols (such as IEC-60870-5-104 or IEC-61850). The downlink acquisition interface can acquire the flywheel speed of all power buffer modules in real time via a high-speed fieldbus (such as EtherCAT or CAN-FD). With supercapacitor voltage and the inlet coolant temperature of all liquid cooling zones. Valve opening feedback The downlink control interface can send power setpoints to the converters of each power buffer module via the same bus. The command frame for the operating mode is sent, and the target opening command is sent to the electronically controlled regulating valves of each liquid cooling zone. .

[0063] The global energy router prioritizes logical groups with high available capacity of their corresponding power buffer modules and low inlet temperatures of their corresponding liquid-cooled zones as service units. The core of its decision-making logic lies in executing a dynamic optimization program. This program, through an internal calculation process, integrates the real-time available capacity status and coolant inlet temperature status of each logical group into a comparable priority index. During each decision-making process, the router calculates and compares this priority index for all logical groups in real time and consistently selects the logical group with the optimal priority index as the service unit. The higher the average available capacity and the lower the average inlet temperature of the battery clusters within a group, the better its priority index. The specific quantitative calculation method for this index (corresponding to a comprehensive state score) is described in detail in subsequent embodiments involving the control method.

[0064] The state assessment model can continuously calculate the comprehensive state score for each battery cluster through a global energy router. First, it is necessary to calculate the available capacity of a single unit. That is, the i-th battery cluster can be calculated based on its buffer module data. The calculation formula is:

[0065] ;

[0066] in, The highest safe operating angular velocity (unit: rad / s) of the flywheel energy storage unit. This refers to the highest rated operating voltage of the supercapacitor unit (unit: V). , which is a weighting coefficient, representing the contribution of the flywheel and the supercapacitor. The larger the value, the stronger the buffering capacity (greater electrical potential) of the cluster to withstand power surges. This corresponds to the fact that the global energy router mentioned earlier can assess the real-time available capacity of each power buffer module based on the rotational speed of the flywheel energy storage unit or the voltage status of the supercapacitor unit.

[0067] Next, the cooling potential of the single unit is calculated. The calculation formula is:

[0068] ;

[0069] in, The upper limit temperature for the cooling system can be set to 35°C. The lowest output temperature for the air conditioner can be set to 20°C. (Result) The lower, The higher the value, the better the heat dissipation.

[0070] Finally, calculate the overall group score. For all battery clusters belonging to the same logical group g, calculate their (α) +β The average of the values ​​is used as the score for that group. Here, α and β are adjustable synergistic coefficients, both of which can be initially set to 0.5 to balance the importance of electricity and heat.

[0071] The program compares all logical groups. The value, and the selection rule, is: always [value]. The group with the highest value is marked as the "candidate service group". The rotation logic is as follows: the program internally has a "current service group" variable and a "minimum continuous service time" variable. (e.g., 5 minutes). If the "candidate service group" is different from the "current service group", and the continuous service time of the "current service group" has exceeded [a certain period], then [the following applies]. If the minimum time requirement is met, a rotation will be triggered. During rotation, the status of the "Current Service Group" will be set to "Hot Recovery," and the status of the "Candidate Service Group" will be set to "Service." If the minimum time requirement has not been met, the original group will be maintained, even if its score is not the highest, to avoid overly frequent switching.

[0072] In this embodiment, the global energy router is configured to: upon receiving a power command from the grid dispatching terminal, decompose the corresponding frequency band (specific frequency modulation command segment) in the power command into high-frequency components and low-frequency components, and preferentially allocate the high-frequency components to the distributed power buffer module array for buffering. After the buffer module mitigates the drastic change in current, the battery cluster array withstands a smooth current, and the liquid cooling system can more easily and efficiently cope with the heat generated by the battery.

[0073] A specific frequency regulation command segment refers to a power command interval issued by the power grid dispatching terminal that has specific characteristics in the time or frequency domain. Its identification and determination are completed in real-time by the global energy router, mainly based on one or more of the following conditions:

[0074] Time-domain rate of change condition: When the change amplitude |ΔP| of the real-time power command P_cmd(t) exceeds a preset proportion (e.g., 20%) of the system's rated power within a very short time (e.g., 100 milliseconds), the time period and the subsequent short duration are determined to be a specific frequency modulation command segment.

[0075] Frequency domain component condition: The router performs real-time spectrum analysis on P_cmd(t). When it detects that the total energy proportion of components above a certain characteristic frequency (e.g., 0.5Hz) in its power spectrum exceeds a preset threshold, it determines that the current command segment is a specific frequency modulation command segment. This characteristic frequency usually corresponds to the critical frequency of thermal hysteresis in liquid cooling systems.

[0076] Command source identification condition: When the power grid dispatching terminal issues certain ancillary service commands that require extremely fast response (such as fast adjustment signals for primary frequency regulation), it may attach a specific service type identifier to the communication protocol. When the router recognizes this identifier, it determines that the subsequent associated power command segment is a specific frequency regulation command segment.

[0077] When any of the above conditions are met, the router will initiate the decomposition and allocation process.

[0078] Specifically, for each control cycle, the received The router performs dynamic allocation: first, it decomposes the instructions, then uses a first-order high-speed digital filter to... Real-time decomposition into low-frequency fundamental components and high-frequency fluctuation components The cutoff frequency is typically set to 0.1-0.5Hz. Then power distribution is performed. The BMS will be directly allocated proportionally to each battery cluster within the current "service group" as its steady-state power reference. Simultaneously, The power buffer modules (transmitters) are mainly allocated to the corresponding battery clusters within this group. ), utilizing its fast response characteristics for throughput.

[0079] After determining the service group, immediately synchronize the cooling: send a command to the electronically controlled valves of the liquid-cooled zones corresponding to all battery clusters within the service group. =85% of the command corresponds to the "enhanced cooling" mode; send to the group in the "heat recovery" state. =40% command, which corresponds to "maintain cooling" mode.

[0080] It is worth mentioning that when the global energy router triggers logical group rotation, it can also dynamically adjust the thermal recovery time of the logical group to which each battery cluster belongs based on the historical cumulative discharge depth and the highest temperature experienced in history.

[0081] Specifically, in the program comparing all logical groups When the value is set, for each logical group g, the program calculates the dynamic thermal recovery time based on the health data of the battery clusters it contains. The calculation formula is as follows:

[0082] ;

[0083] in, Indicates the basic thermal recovery time; and γ and δ represent the average historical depth of discharge factor and average historical overtemperature degree of the battery clusters within the group, respectively; γ and δ are influence coefficients used to adjust the weight of the influence of historical factors on recovery time.

[0084] This formula allows groups with more severe historical fatigue (more cumulative discharge, and exposure to high temperatures) to have a longer resting recovery time after being taken out of service, so as to fully release the internal accumulated stress.

[0085] To dynamically adjust the thermal recovery time of a logical group, the cumulative charge throughput can be calculated and normalized using the total charge / discharge ampere-hours recorded by the BMS to obtain the average historical depth of discharge factor representing the battery clusters within that group. Furthermore, by analyzing historical temperature alarms and sampling logs from the BMS, the highest temperature value ever reached by each cluster can be extracted. This data is then pushed to the global energy router via the BMS's periodic reporting function. Based on the latest battery cluster performance degradation data, the influence coefficients γ and δ in the formula are fine-tuned to make the predictive management model more closely reflect actual aging conditions.

[0086] Please see Figure 2 As shown, this embodiment also provides a control method for fast frequency regulation, applied to the battery energy storage system for fast frequency regulation disclosed in the embodiment. This method can be executed by a global energy router and may include the following steps:

[0087] Step 1: Receive real-time power commands from the power grid dispatching terminal.

[0088] In this embodiment, the global energy router can continuously monitor and receive real-time power commands issued by the power grid dispatching system through its uplink communication interface. The instruction is usually issued in the form of a time-stamped setpoint, requiring the energy storage to track its changes within a time frame of milliseconds to seconds. After parsing and validating the instruction, the router uses it as the input trigger signal for the entire process.

[0089] Step 2: Obtain the available capacity status of each distributed power buffer module and the cooling status of each liquid cooling zone.

[0090] Among them, available capacity status and cooling status refer to the two core input dimensions for the global energy router to make decisions. Available capacity status quantifies the potential of the power buffer module to withstand power fluctuations, while cooling status quantifies the real-time heat dissipation conditions of the corresponding battery cluster. The comprehensive evaluation of the two aims to achieve electrothermal synergistic optimization.

[0091] In this embodiment, before responding to the command, the global energy router can synchronously collect two key real-time status datasets through its downlink data bus: electrical buffer status: reading the current flywheel speed from the controller of each distributed power buffer module. With the current voltage of the supercapacitor These raw data directly reflect the instantaneous energy storage and release capability of each module; thermal management status: reading the coolant inlet temperature from sensors in each independent liquid-cooled zone. This temperature is a key parameter for assessing the immediate heat dissipation potential of the partition.

[0092] Step 3: Based on the available capacity status and cooling status, select a subset of all battery clusters as the currently serving cluster.

[0093] Furthermore, the step of selecting the currently serving cluster based on available capacity status and cooling status may include:

[0094] Divide the battery cluster into at least two logical groups; calculate the comprehensive status score of each logical group. The comprehensive status score is positively correlated with the available capacity of the power module corresponding to each battery cluster in the group and negatively correlated with the inlet temperature of the liquid cooling partition corresponding to each battery cluster; select the logical group with the highest comprehensive status score as the current service cluster.

[0095] In this embodiment, the global energy router can compare all logical packets. The value determines the battery clusters included in the logical group with the highest overall status score, which are then selected as the currently operational clusters. This group will then exit the thermal recovery state and begin to perform power tasks.

[0096] Step 4: Distribute real-time power commands to the distributed power buffer modules corresponding to the currently serving clusters.

[0097] In this embodiment, the router receives the data in step one. This is allocated to the power buffer module corresponding to the currently serving cluster. Specifically, the router can generate... Proportional power setting The control bus sends commands to the local controllers of these modules, driving the flywheel and supercapacitor to quickly absorb or release power, thereby smoothing out high-frequency fluctuations in the commands and protecting the battery clusters at the back end.

[0098] Step 5: Synchronously adjust the cooling intensity of the liquid cooling zone corresponding to the currently serving cluster.

[0099] In this embodiment, while allocating power commands, the global energy router sends control commands to the flow control valves of each liquid cooling zone bound to the currently serving cluster, setting their opening degree to a certain value. Adjust to a higher "active cooling" setting (e.g., 80% of rated opening) to immediately enhance heat dissipation for that section of the battery cluster. For the liquid-cooled section containing non-service clusters, set its opening to a lower "maintenance cooling" setting (e.g., 30% of rated opening).

[0100] In summary, by constructing a distributed power buffer module array to form the first active defense line in the electrical path, the drastically changing high-frequency components in the power command from the grid dispatching terminal are decoupled from the DC current flowing to the battery cluster. Physical buffering smooths out the rate of change of current experienced by the battery, thereby suppressing the severe internal heat fluctuations caused by millisecond-level current drastic changes at the source. The partitioned counter-current liquid cooling subsystem constitutes a precisely matched second heat conduction defense line. Through topology reconstruction, the distribution logic of the cooling medium spontaneously matches the spatial distribution of the system's heat load. The design improves the uniformity of heat dissipation within a single cluster, while the temperature gradient field formed by the series connection enables on-demand allocation of cooling capacity, ensuring that the heat generated by the battery can be efficiently and evenly dissipated, avoiding heat accumulation and localized overheating caused by delayed or uneven heat dissipation. The global energy router, acting as the system's brain, forms the third intelligent scheduling defense line. By integrating electrical buffer capacity and heat dissipation status information in real time, it dynamically selects the optimal working unit and simultaneously enhances its cooling, while arranging controlled thermal recovery periods for other units. This breaks the vicious cycle of continuous electrothermal stress accumulation and fatigue damage from the system operation strategy perspective. Through the seamless connection and closed-loop operation of these three defense lines, the millisecond-level power surges from the outside are transformed into a smooth thermal load and periodic stress relaxation within the battery. This solves the problem of localized thermal runaway in battery energy storage systems under rapid frequency regulation scenarios, ensuring the safety and durability of the battery energy storage system during long-term, high-intensity rapid frequency regulation service.

[0101] By introducing a power buffer module that combines a flywheel and a supercapacitor, the flywheel, with its huge rotational inertia, can handle power shortages or excesses lasting for several seconds, while the supercapacitor can handle transient power spikes with a millisecond-level response speed. The two are physically coaxially coupled to form a hybrid power system with complementary response characteristics, which completely decouples the battery cluster from the high-frequency power fluctuations on the grid side and always operates under a gradually changing current condition. This eliminates the physical conditions that cause peeling forces between active material particles and current collectors due to rapid changes in current inside the battery, and improves the efficiency of full-band decomposition and processing of grid power commands.

[0102] By implementing a dynamic grouping and rotation scheduling strategy based on real-time electrothermal state fusion assessment through a global energy router, the battery cluster array is divided into logical groups and assigned alternating states of service and thermal recovery. By calculating the comprehensive state score of each group in real time and always prioritizing the group with the highest score to undertake power tasks, while ensuring that the remaining groups obtain a full thermal recovery time, this mechanism actively creates a periodic thermal stress relaxation window at the system level. This enables the battery to effectively restore its microstructural stability after experiencing electrochemical and thermal loads, thereby breaking the chain of continuous and irreversible fatigue damage accumulation in traditional operation.

[0103] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

[0104] In conclusion, the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A battery energy storage system for fast frequency regulation, comprising a battery cluster array, a high-voltage box, and a power converter, characterized in that, The system includes: A distributed power buffer module array is set up one-to-one with the battery clusters in the battery cluster array and electrically connected between the corresponding battery cluster and the high-voltage box. It is used to absorb or release high-frequency fluctuation components in the power command from the power grid dispatching terminal. The partitioned counter-current liquid cooling subsystem includes a liquid cooling partition set up independently for each battery cluster. The cooling circuit of each liquid cooling partition adopts a counter-current arrangement with the inlet located at the top of the battery cluster and the outlet located at the bottom of the battery cluster. The global energy router is connected to the distributed power buffer module array and the partitioned counter-current liquid cooling subsystem. It is used to select some battery clusters as service units to execute power commands based on power commands and the status of each power buffer module, and to synchronously adjust the cooling intensity of the corresponding liquid cooling partition.

2. The battery energy storage system for rapid frequency regulation according to claim 1, characterized in that, The distributed power buffer module is a flywheel-supercapacitor composite module, which includes a flywheel energy storage unit and a supercapacitor unit that are physically coaxially connected.

3. A battery energy storage system for rapid frequency regulation according to claim 2, characterized in that, The global energy router assesses the real-time available capacity of each power buffer module based on the rotational speed of the flywheel energy storage unit or the voltage status of the supercapacitor unit.

4. A battery energy storage system for fast frequency regulation according to claim 1, characterized in that, The cooling circuits of each liquid cooling zone are connected in series through pipelines, so that the coolant inlet of the liquid cooling zone far away from the high-voltage box is connected to the coolant outlet of the liquid cooling zone adjacent to the high-voltage box, thereby forming a coolant temperature gradient field in the arrangement direction of the battery cluster array.

5. A battery energy storage system for rapid frequency regulation according to claim 1, characterized in that, The battery cluster array is pre-divided into at least two logical groups; the global energy router is configured to: control one logical group as the service unit when responding to a power command, control the remaining logical groups to be in a hot recovery state, and periodically or according to the state trigger the rotation between logical groups.

6. A battery energy storage system for rapid frequency regulation according to claim 5, characterized in that, The global energy router prioritizes logical packets with high available capacity of the corresponding power buffer module and low inlet temperature of the corresponding liquid-cooled partition as service units.

7. A battery energy storage system for rapid frequency regulation according to claim 5, characterized in that, When triggering logical group rotation, the global energy router also dynamically adjusts the thermal recovery time of the logical group to which each battery cluster belongs, based on the historical cumulative discharge depth or the highest temperature experienced in history.

8. A battery energy storage system for rapid frequency regulation according to claim 1, characterized in that, The global energy router is configured to: upon receiving a power command from the power grid dispatching terminal, decompose the corresponding frequency band in the power command into high-frequency components and low-frequency components, and prioritize the allocation of the high-frequency components to be buffered by the distributed power buffer module array.

9. A control method for rapid frequency regulation, applied to a battery energy storage system for rapid frequency regulation as described in any one of claims 1-8, characterized in that, The method is executed by a global energy router and includes the following steps: Receive real-time power commands from the power grid dispatching terminal; Obtain the available capacity status of each distributed power buffer module and the cooling status of each liquid cooling zone; Based on available capacity status and cooling status, a subset of all battery clusters is selected as the currently serving cluster; Distribute real-time power commands to the distributed power buffer modules corresponding to the currently serving clusters; Synchronously adjust the cooling intensity of the liquid cooling zone corresponding to the currently serving cluster.

10. A control method for fast frequency modulation according to claim 9, characterized in that, The steps for selecting the currently serving cluster based on available capacity and cooling status include: Divide the battery clusters into at least two logical groups; Calculate the comprehensive status score of each logical group. The comprehensive status score is positively correlated with the available capacity of the power module corresponding to each battery cluster in the group, and negatively correlated with the inlet temperature of the liquid cooling zone corresponding to each battery cluster. The logical group with the highest overall status score is selected as the currently serving cluster.

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