Large-scale composite energy storage system

Abstract

The present disclosure relates to a large-scale composite energy storage system. The system comprises: a grid-coupling platform connected with an alternating current grid through a grid interface unit; an electrical energy coupling platform for controlling a short-time energy storage unit, a long-time energy storage power unit in the electrical energy coupling platform, and a long-time energy storage energy unit in a long-time energy platform according to power and energy scheduling requirements; a thermal energy coupling platform for controlling the temperature and thermal energy distribution of the large-scale composite energy storage system; a chemical energy coupling platform for optimizing the long-time energy platform to achieve balance, recovery and regeneration control of electrolyte according to the control requirements of the long-time energy storage power unit in the electrical energy coupling platform; and a capacity regeneration coupling platform for realizing capacity regeneration according to the capacity regeneration requirements of the chemical energy coupling platform. In this way, through the innovative idea and method of establishing direct or indirect cross-coupling paths in three dimensions of electrical energy, thermal energy and chemical energy, the optimal utilization of electrical energy, thermal energy and chemical energy can be achieved.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of energy storage, in particular, to a large-scale composite energy storage system. BACKGROUND

[0002] The rapid development of new power systems has put forward an urgent demand for the development of large-scale energy storage systems of hundreds of megawatts. Current hundreds of megawatt energy storage systems are mainly divided into short-time energy storage systems represented by lithium ion batteries and long-time energy storage systems represented by all-vanadium redox flow batteries. However, the two types of energy storage systems use different system solutions, system architectures and control methods, which hinder the development of large-scale energy storage. SUMMARY

[0003] The purpose of the present disclosure is to provide a large-scale composite energy storage system to better realize the complementary integration of short-time energy storage and long-time energy storage by establishing an innovative idea and method of directly or indirectly cross-coupling paths in three dimensions of electrical energy, thermal energy and chemical energy.

[0004] In order to achieve the above-mentioned purpose, the present disclosure provides a large-scale composite energy storage system, comprising:

[0005] A grid-coupling platform is connected with an alternating current grid through a grid interface unit, and is used to provide an energy interface for the large-scale composite energy storage system to realize energy management control and grid state monitoring functions;

[0006] An electrical energy coupling platform is used to control short-time energy storage units, long-time energy storage power units in the electrical energy coupling platform, and long-time energy storage energy units in a long-time energy platform according to scheduling requirements of power and energy, so as to realize power coupling conversion and energy flow control of the large-scale composite energy storage system, wherein the scheduling requirements are determined based on the grid monitoring state;

[0007] A thermal energy coupling platform is used to control temperature changes and thermal energy distribution of the large-scale composite energy storage system according to thermal management distribution characteristics of short-time energy storage and thermal management distribution characteristics of long-time energy storage;

[0008] A chemical energy coupling platform is used to optimize the long-time energy platform according to control requirements of long-time energy storage power units in the electrical energy coupling platform, so as to realize balance, recovery and regeneration control of electrolyte;

[0009] A capacity regeneration coupling platform is used to realize capacity regeneration by coupling the grid-coupling platform according to capacity regeneration requirements of the chemical energy coupling platform.

[0010] Optionally, the grid-coupling platform comprises a three-phase first subsystem, each phase of the first subsystem comprises N cascaded DC-AC converters connected in series, and a three-phase common ground side is connected with the capacity regeneration coupling platform.

[0011] The cascaded DC-AC converter is used to convert the energy provided by the AC power grid into DC power and input the DC power into the electric energy coupling platform, or convert the DC power of the electric energy coupling platform into AC power and input the energy into the AC power grid.

[0012] The grid-connected coupling platform is further used to convert the energy provided by the AC power grid into AC power of a target voltage and input the AC power of the target voltage into the capacity regenerative coupling platform.

[0013] Optionally, the electric energy coupling platform comprises a three-phase second subsystem, each phase of the second subsystem comprising M electric energy coupling modules, each of the electric energy coupling modules comprising a short-time energy storage unit, a long-time energy storage power unit, a bidirectional DC-DC isolation unit, a short-time heat dissipation unit, a chemical energy supply unit, a DC power interface end, a short-time heat energy interface end, a long-time heat energy interface end, and a long-time chemical energy interface end.

[0014] The DC power interface end is connected with the short-time energy storage unit and the grid-connected coupling platform and connected with the long-time energy storage power unit through the bidirectional DC-DC isolation unit.

[0015] The short-time heat energy interface end is connected with the short-time energy storage unit through the short-time heat dissipation unit and connected with a first target heat management device, wherein the first target heat management device comprises at least one of an independent heat dissipation unit and a short-time unit heat energy interface end of other electric energy coupling modules.

[0016] The long-time heat energy interface end is connected with the long-time energy storage power unit and a second target heat management device, wherein the second target heat management device comprises at least one of an independent heat dissipation unit and a long-time unit heat energy interface end of other electric energy coupling modules.

[0017] The chemical energy supply unit connects the short-time energy storage unit with the chemical energy coupling platform through the long-time chemical energy interface end.

[0018] Optionally, the first target heat management device and the second target heat management device are determined according to an optimization target of a heat dissipation system corresponding to the large-scale composite energy storage system, and the optimization target is used to realize coupling between short-time heat management units, between long-time heat management units, or between the short-time heat management units and the long-time heat management units with a system minimum heat energy loss as a target.

[0019] Optionally, the long-time energy storage power unit is configured to realize bidirectional conversion between chemical energy and electrical energy in the long-time energy storage pipeline according to a long-time energy storage energy management target, wherein the energy conversion mode of the long-time energy storage chemical energy and electrical energy is determined based on the corresponding long-time energy storage pipeline system of the large-scale composite energy storage system, and the long-time energy storage chemical energy and electrical energy energy conversion optimization process includes long-time energy storage power unit self-driving optimization and long-time energy storage power unit coupling driving optimization with other electrical energy coupling modules.

[0020] Optionally, the thermal energy coupling platform includes a three-phase third subsystem, each phase of the third subsystem includes O thermal energy coupling modules, each of the thermal energy coupling modules includes a short-time thermal energy management unit, a long-time thermal energy management unit, and a thermal coupling heat dissipation unit.

[0021] The short-time thermal energy management unit is connected to a short-time thermal energy interface end of the electrical energy coupling platform.

[0022] The long-time thermal energy management unit is connected to a long-time thermal energy interface end of the electrical energy coupling platform.

[0023] The thermal coupling heat dissipation unit is connected to the short-time thermal energy management unit and the long-time thermal energy management unit, and the thermal coupling heat dissipation unit includes a heat storage unit.

[0024] Optionally, the chemical energy coupling platform includes a three-phase fourth subsystem, each phase of the fourth subsystem includes P chemical energy coupling modules, each of the chemical energy coupling modules includes an electrolyte flow driving unit, an online capacity balancing unit, an online capacity repair unit, and an online capacity regeneration management unit.

[0025] The electrolyte flow driving unit is connected to the chemical energy power supply unit of the electrical energy coupling platform and the long-time energy storage power unit, and is configured to drive circulation of the electrolyte in multiple long-time energy storage power units according to charge and discharge requirements of the long-time energy storage power unit, wherein the electrolyte flow driving unit and the long-time energy storage power unit are connected through an electrolyte pipeline.

[0026] The online capacity balancing unit is connected to the electrolyte flow driving unit and connected to multiple long-time energy storage energy units of the long-time energy platform through distribution of the electrolyte pipeline, and is configured to drive capacity balancing distribution of the electrolyte in multiple long-time energy storage energy units according to capacity balancing requirements of the long-time energy platform.

[0027] The online capacity repair unit is connected with the electrolyte flow driving unit, and is connected with the plurality of long-time energy storage energy units of the long-time energy platform through distribution of the electrolyte pipeline, and is used for driving capacity repair distribution of the electrolyte in the plurality of long-time energy storage energy units according to capacity repair requirements of the long-time energy platform.

[0028] The online capacity regeneration management unit is connected with the electrolyte flow driving unit and the capacity regeneration coupling platform, and is connected with the plurality of long-time energy storage energy units of the long-time energy platform through distribution of the electrolyte pipeline, and is used for driving capacity regeneration distribution of the electrolyte in the plurality of long-time energy storage energy units according to capacity regeneration requirements of the long-time energy platform.

[0029] Optionally, the chemical energy coupling platform further comprises a short-time energy storage safety management module connected with the short-time energy storage unit of the electrical energy coupling platform, and used for performing capacity control on the short-time energy storage unit according to safety operation requirements.

[0030] Optionally, the long-time energy platform comprises a three-phase fifth subsystem, each phase of the fifth subsystem comprising Q long-time energy storage energy units, and the long-time energy storage energy unit comprising a positive tank and a negative tank.

[0031] The long-time energy storage energy unit is connected with the long-time energy storage power unit of the electrical energy coupling platform through the chemical energy coupling platform and the electrical energy coupling platform, so as to realize online capacity balancing and online capacity repair.

[0032] The long-time energy storage energy unit is further connected with the capacity regeneration coupling platform through the chemical energy coupling platform, so as to realize online capacity regeneration.

[0033] Optionally, the long-time energy platform is further used for coupling processing of a thermal coupling heat dissipation unit, a short-time thermal energy management unit or a long-time thermal energy management unit in the thermal energy coupling platform according to temperature control and thermal energy distribution requirements, so as to perform optimization regulation and energy distribution.

[0034] Optionally, the capacity regeneration coupling platform comprises R three-phase parallel AC-DC converters and a long-time energy storage capacity regeneration unit corresponding to each AC-DC converter, wherein the AC-DC converter is connected with a three-phase common ground side of the grid-connected coupling platform; the long-time energy storage capacity regeneration unit comprises a regeneration anode tank, a regeneration cathode tank and a regeneration power management unit used for realizing electrolysis.

[0035] The long-time energy storage capacity regeneration unit is connected with the online capacity regeneration management unit of the chemical energy coupling platform, connected with the positive tank and the negative tank of the long-time energy platform through distribution of electrolyte pipelines, used for guiding electrolyte needing regeneration in the long-time energy storage energy unit into the regeneration anode tank or the regeneration cathode tank of the long-time energy storage capacity regeneration unit when in the regeneration mode; and electrolysis is carried out through the AC-DC converter after adding regeneration material to complete the regeneration process of the electrolyte, and the regenerated electrolyte is controlled to flow from the regeneration anode tank and the regeneration cathode tank to the positive tank and the negative tank respectively through the online capacity regeneration management unit to realize system capacity regeneration distribution.

[0036] Optionally, the long-time energy storage capacity regeneration unit is also used for, when not in the regeneration mode, controlling the AC end of the AC-DC converter to keep a zero voltage point, and the DC end to keep an operating reference voltage in the electrolytic cell, and the regeneration anode tank and the regeneration cathode tank to keep in an active standby state.

[0037] Optionally, the large-scale composite energy storage system further comprises a controller, and the controller is used for:

[0038] controlling the large-scale composite energy storage system to perform self-checking, wherein the self-checking comprises periodic fault self-checking, aperiodic fault self-checking, capacity self-checking and temperature condition self-checking, and the aperiodic fault self-checking is performed when a target parameter in the large-scale composite energy storage system reaches a corresponding reference threshold value;

[0039] if the self-checking passes, determining a scheduling demand of power and energy of the alternating current power grid;

[0040] according to the scheduling demand, starting corresponding platforms in the large-scale composite energy storage system in sequence;

[0041] after the grid-connected coupling platform is started, starting a target operating mode according to a grid monitoring state.

[0042] Optionally, the controller is further used for:

[0043] if a periodic fault self-checking result or an aperiodic fault self-checking result is abnormal, isolating or removing a fault point.

[0044] Optionally, the controller is further used for:

[0045] if the periodic fault self-checking result and the aperiodic fault self-checking result are not abnormal, performing the capacity self-checking.

[0046] Optionally, the controller is further used for:

[0047] If the capacity self-checking result is abnormal, the controller controls the large-scale composite energy storage system to perform online capacity balancing, repair, or capacity regeneration.

[0048] If the capacity self-checking result is normal, the controller performs the temperature condition self-checking.

[0049] Optionally, the controller is further configured to:

[0050] If the temperature condition self-checking result is abnormal, the controller controls the thermal energy coupling platform to start up.

[0051] If the temperature condition self-checking result is normal, the controller determines the scheduling requirement.

[0052] Optionally, the controller is configured to start up corresponding platforms in the large-scale composite energy storage system in sequence according to the scheduling requirement by:

[0053] If the scheduling requirement has a long-time energy requirement, the controller controls the long-time energy storage power unit of the electrical energy coupling platform, the electrolyte flow driving unit of the chemical energy coupling platform, the long-time energy platform, and the grid-connected coupling platform to start up in sequence.

[0054] If the scheduling requirement has a short-time energy requirement, the controller controls the short-time energy storage unit of the electrical energy coupling platform and the grid-connected coupling platform to start up in sequence.

[0055] Optionally, the grid monitoring state is determined based on grid impedance.

[0056] Optionally, the target operation mode includes a grid-following structure and parameters in a grid-connected mode, a grid-forming structure and parameters in a grid-connected mode, or a grid-forming structure and parameters in an off-grid mode.

[0057] In the technical solution, the grid coupling platform is connected with the alternating current grid through the grid interface unit, and is used to provide an energy interface for the large-scale composite energy storage system to realize energy management control and grid state monitoring; the electric energy coupling platform is used to control the short-time energy storage unit, the long-time energy storage power unit in the electric energy coupling platform, and the long-time energy storage energy unit in the long-time energy platform according to the scheduling demand of power and energy, so as to realize power coupling conversion and energy flow control of the large-scale composite energy storage system, wherein the scheduling demand is determined based on the grid monitoring state; the thermal energy coupling platform is used to control temperature change and thermal energy distribution of the large-scale composite energy storage system according to the thermal management distribution characteristics of the short-time energy storage and the thermal management distribution characteristics of the long-time energy storage; the chemical energy coupling platform is used to optimize the long-time energy platform according to the control demand of the long-time energy storage power unit in the electric energy coupling platform, so as to realize balance, recovery and regeneration control of the electrolyte; and the capacity regeneration coupling platform is used to realize capacity regeneration by coupling the grid coupling platform according to the capacity regeneration requirement of the chemical energy coupling platform. In this way, by establishing the innovative idea and method of directly or indirectly cross-coupling paths in three dimensions of electric energy, thermal energy and chemical energy, the complementary fusion characteristics of the short-time energy storage and the long-time energy storage can be utilized, the energy and power distribution between the short-time energy storage and the long-time energy storage can be optimized, the optimized utilization of electric energy, thermal energy and chemical energy can be realized, the online repair and regeneration of the coupling modules can be realized, the energy and material loss of the coupling modules can be reduced, the network active support capability of the hybrid energy storage mode can be provided, and the long-time, reliability and safety of the large-scale composite energy storage system can be improved.

[0058] Other features and advantages of the present disclosure will be described in detail in the following detailed description section. BRIEF DESCRIPTION OF DRAWINGS

[0059] The accompanying drawings are included to provide a further understanding of the present disclosure and constitute a part of the specification, which together with the detailed description, serve to explain the present disclosure. In the drawings:

[0060] Figure 1 is a schematic diagram of an energy storage system in the related art.

[0061] Figure 2 is a block diagram of a large-scale composite energy storage system provided by an example embodiment of the present disclosure.

[0062] Figure 3 is a schematic diagram of a large-scale composite energy storage system provided by an example embodiment of the present disclosure. DETAILED DESCRIPTION

[0063] The detailed description of the specific embodiments of the present disclosure is described below in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present disclosure, and are not used to limit the present disclosure.

[0064] Current megawatt-level energy storage systems are mainly divided into short-time energy storage systems represented by lithium ion batteries and long-time energy storage systems represented by all-vanadium redox flow batteries, such as Figure 1 As shown, the two types of energy storage systems adopt different system solutions, system architectures and control methods, and cannot overcome their own shortcomings through coupling complementary effects, for example, lithium batteries have a large potential safety risk, and flow batteries have high costs, which hinder the development of large-scale energy storage. In order to solve the above problems and better expand the scale of energy storage, the present disclosure provides a large-scale composite energy storage system to realize the complementary fusion of short-time energy storage and long-time energy storage through the innovative idea and method of establishing direct or indirect cross-coupling paths in three dimensions of electrical energy, thermal energy and chemical energy.

[0065] In the following description, the words "first", "second", and the like, are used only to distinguish the described purposes, and cannot be understood as indicating or implying relative importance, nor indicating or implying order.

[0066] Figure 2 is a block diagram of a large-scale composite energy storage system provided by an exemplary embodiment of the present disclosure. As shown in Figure 2 The large-scale composite energy storage system includes a grid-coupling platform 10, a grid interface unit 11, an electrical energy coupling platform 12, a thermal energy coupling platform 13, a chemical energy coupling platform 14, a long-time energy platform 15, and a capacity regeneration coupling platform 16.

[0067] The grid-coupling platform 10 is connected with an alternating current grid through the grid interface unit 11, and is used to provide an energy interface for the large-scale composite energy storage system to realize energy management control and grid state monitoring functions;

[0068] The electrical energy coupling platform 12 is used to control the short-time energy storage unit 121, the long-time energy storage power unit 122 in the electrical energy coupling platform 12, and the long-time energy storage energy unit in the long-time energy platform 15 according to the scheduling demand of power and energy, to realize power coupling conversion and energy flow control of the large-scale composite energy storage system, wherein the scheduling demand is determined based on the grid monitoring state;

[0069] The thermal energy coupling platform 13 is used to control the temperature change and thermal energy distribution of the large-scale composite energy storage system according to the thermal management distribution characteristics of the short-time energy storage and the thermal management distribution characteristics of the long-time energy storage;

[0070] The chemical energy coupling platform 14 is used to optimize the long-time energy platform 15 according to the control demand of the long-time energy storage power unit 122 in the electrical energy coupling platform 12, to realize the balance, recovery and regeneration control of the electrolyte;

[0071] A capacity regeneration coupling platform 16 is configured to perform capacity regeneration through the grid-connected coupling platform 10 according to a capacity regeneration requirement of the chemical energy coupling platform 14.

[0072] For example, the alternating current grid can be a grid for new energy power generation, such as a grid for wind power generation. The scheduling demand of power and energy of the grid can be determined by a controller of the controller of the grid scheduling center, that is, the controller of the energy management system (EMS), or can be determined by the EMS according to the operating state. That is, the EMS can autonomously generate the scheduling demand of power and energy, or can receive the scheduling demand of power and energy issued by the upper computer of the grid scheduling center.

[0073] The scheduling demand of power and energy can include long-time energy demand and / or short-time energy demand. If the scheduling demand of power and energy has long-time energy demand, the long-time energy storage power unit 122 of the electrical energy coupling platform 12 and the long-time energy storage energy unit in the long-time energy platform 15 can be controlled to act, and if the scheduling demand of power and energy has short-time energy demand, the short-time energy storage unit 121 of the electrical energy coupling platform 12 can be controlled to act. The chemical energy coupling platform 14 can optimize the long-time energy platform 15 according to the control requirement of the long-time energy storage power unit 122 in the electrical energy coupling platform 12, and the chemical energy coupling platform 14 can control the flow state (such as flow rate) of the electrolyte in the positive tank and the negative tank in the long-time energy platform 15, so that the long-time energy storage power unit 122 in the electrical energy coupling platform 12 can normally operate, and realize the balance, recovery and regeneration control of the electrolyte.

[0074] The thermal management distribution feature refers to the distribution state of heat at the current time. Through the thermal energy coupling platform 13, the distributed flow characteristics of the short-time energy storage liquid cooling and the long-time energy storage electrolyte can be combined with the thermal management distribution features of the short-time energy storage and the long-time energy storage, the thermal management requirements in different modes such as refrigeration and heat dissipation and heat supply start-up can be combined, and the comprehensive thermal management efficiency of the large-scale composite energy storage system can be improved.

[0075] Through the setting of the capacity regeneration coupling platform 16, capacity regeneration can be realized through the grid-connected coupling platform 10 according to the capacity regeneration requirement of the chemical energy coupling platform 14, so as to reduce the energy and material loss of the coupling module, provide active support capability for network construction in the mixed energy storage mode, and improve the long-time nature, reliability and safety of the large-scale composite energy storage system.

[0076] In the above technical solution, the grid-connected coupling platform connects to the AC grid through a grid interface unit to provide an energy interface for the large-scale composite energy storage system, enabling energy management control and grid status monitoring. The electrical coupling platform controls the short-term energy storage units, long-term energy storage power units, and long-term energy storage energy units in the long-term energy platform according to power and energy dispatch requirements, achieving power coupling conversion and energy flow control for the large-scale composite energy storage system. The dispatch requirements are determined based on the grid monitoring status. The thermal coupling platform controls the temperature changes and thermal distribution of the large-scale composite energy storage system based on the thermal management distribution characteristics of short-term and long-term energy storage. The chemical energy coupling platform optimizes the long-term energy platform according to the control requirements of the long-term energy storage power units in the electrical coupling platform, enabling the balance, recovery, and regeneration control of the electrolyte. The capacity regeneration coupling platform achieves capacity regeneration by coupling the grid-connected coupling platform according to the capacity regeneration requirements of the chemical energy coupling platform. Thus, by establishing innovative ideas and methods for direct or indirect cross-coupling paths of electrical energy, thermal energy, and chemical energy, we can leverage the complementary and integrated characteristics of short-term and long-term energy storage, optimize the energy and power distribution between them, and achieve optimized utilization of electrical, thermal, and chemical energy. This also enables online repair and regeneration of the coupling modules, reduces energy and material losses, provides active support for the construction of hybrid energy storage systems, and ultimately improves the long-term performance, reliability, and safety of large-scale composite energy storage systems.

[0077] In an alternative embodiment, such as Figure 3 As shown, the grid-connected coupling platform 10 may include a three-phase first subsystem, each of which includes N cascaded DC-AC converters connected in series, and the three-phase common ground side is connected to the capacity regeneration coupling platform 16.

[0078] The cascaded DC-AC converter is used to convert the energy provided by the AC grid into DC power and input the DC power to the power coupling platform 12, or to convert the DC power of the power coupling platform 12 into AC power and input the energy to the AC grid.

[0079] The grid-connected coupling platform 10 is also used to convert the energy provided by the AC grid into AC power at the target voltage, and input the AC power at the target voltage to the capacity regeneration coupling platform 16.

[0080] The three-phase common ground side is connected with the three-phase AC-DC converter 161 of the capacity regenerative coupling platform 16. N can be a positive integer. The DC side of the first subsystem is connected with the direct current end of the electric energy coupling platform 12, and the AC side is sequentially connected in series to form a low-voltage end and a high-voltage end. The high-voltage end is connected with the power grid interface unit 11, and the low-voltage end is connected with the capacity regenerative coupling platform 16, that is, the alternating current of the target voltage is low-voltage alternating current. The state of the DC-AC converter can be independently controlled based on the high-frequency PWM (pulse width modulation) switching frequency, or jointly controlled based on the low-frequency switching frequency of the cascaded H-bridge, so that the system efficiency can be improved.

[0081] In an optional embodiment, as shown in Figure 3 The electric energy coupling platform 12 can include three-phase second subsystems, each phase second subsystem including M electric energy coupling modules, each electric energy coupling module including a short-time energy storage unit 121, a long-time energy storage power unit 122, a bidirectional DC-DC isolation unit 123, a short-time heat dissipation unit 124, a chemical energy supply unit 125, a direct current electric energy interface end, a short-time heat energy interface end, a long-time heat energy interface end, and a long-time chemical energy interface end.

[0082] The direct current electric energy interface end is connected with the short-time energy storage unit 121 and the grid coupling platform 10, and is connected with the long-time energy storage power unit 122 through the bidirectional DC-DC isolation unit 123.

[0083] The short-time heat energy interface end is connected with the short-time energy storage unit 121 through the short-time heat dissipation unit 124, and is connected with a thermal management first target device, wherein the thermal management first target device includes at least one of an independent heat dissipation unit and a short-time unit heat energy interface end of other electric energy coupling modules.

[0084] The long-time heat energy interface end is connected with the long-time energy storage power unit 122 and a thermal management second target device, wherein the thermal management second target device includes at least one of an independent heat dissipation unit and a long-time unit heat energy interface end of other electric energy coupling modules.

[0085] The chemical energy supply unit 125 connects the short-time energy storage unit 121 with the chemical energy coupling platform 14 through the long-time chemical energy interface end.

[0086] M can be a positive integer, and each phase second subsystem can include the same number of electric energy coupling modules. Based on the structure of the electric energy coupling platform 12 described above, the large-scale composite energy storage system can effectively utilize the characteristics of the organic and flexible combination of high-voltage isolation and non-isolation power conversion in different links in terms of power conversion. Based on the complementary principle of the non-isolation design of the short-time energy storage and the isolation design of the long-time energy storage, the comprehensive efficiency improvement potential of power conversion can be fully utilized.

[0087] For example, the DC power interface end is connected to the DC end of the short-time energy storage unit 121 inside the energy coupling module, and is connected to the DC end of the long-time energy storage power unit 122 through a bidirectional DC-DC isolation unit 123; the DC power interface end is connected to the DC end of the grid coupling platform 10. The short-time heat energy interface end can be connected to the short-time energy storage unit 121 through a short-time heat dissipation unit 124, and can be independently cooled or connected to the short-time heat energy interface end of other energy coupling modules according to the structure design of the heat dissipation system; the long-time heat energy interface end can connect the long-time heat energy management unit 132 of the heat energy coupling platform 13 to the long-time energy storage power unit 122, and can be independently cooled or connected to the long-time heat energy interface end of other energy coupling modules according to the structure design of the heat dissipation system; the long-time chemical energy interface end can be connected to the chemical energy power supply unit 125, and can be independently controlled or coupled and driven by the chemical energy pipeline of the long-time power module of other energy coupling modules through the structure design of the pipeline system.

[0088] In an optional embodiment, the thermal management first target device and the thermal management second target device are determined according to the optimization target of the heat dissipation system corresponding to the large-scale composite energy storage system, and the optimization target is used to realize the coupling between the short-time thermal management units 131, between the long-time thermal management units 132, or between the short-time thermal management units 131 and the long-time thermal management units 132, with the minimum heat energy loss of the system as the target.

[0089] The parts in the large-scale composite energy storage system have different demands for heat energy, and by setting the optimization target, the excess heat of part A in the large-scale composite energy storage system can be transferred to part B which needs heat energy, so as to reduce the overall heat energy loss of the large-scale composite energy storage system.

[0090] In an optional embodiment, the long-time energy storage power unit 122 is used to realize the bidirectional conversion of chemical energy and electrical energy in the long-time energy storage pipeline according to the long-time energy storage energy management target, wherein the energy conversion mode of the long-time energy storage chemical energy and electrical energy is determined based on the long-time energy storage pipeline system corresponding to the large-scale composite energy storage system, and the energy conversion optimization process of the long-time energy storage chemical energy and electrical energy includes self-driving optimization of the long-time energy storage power unit 122 and coupled driving optimization of the long-time energy storage power unit 122 of other energy coupling modules.

[0091] For example, the long-time energy storage energy management target can be determined based on the grid detection state.

[0092] In an optional embodiment, as shown in Figure 3 The heat energy coupling platform 13 can include three-phase third subsystems, each phase third subsystem including O heat energy coupling modules, and each heat energy coupling module including a short-time heat energy management unit 131, a long-time heat energy management unit 132, and a heat coupling heat dissipation unit 133.

[0093] The short-time thermal energy management unit 131 is connected to the short-time thermal energy interface end of the electric energy coupling platform 12;

[0094] The long-time thermal energy management unit 132 is connected to the long-time thermal energy interface end of the electric energy coupling platform 12;

[0095] The thermal coupling heat dissipation unit 133 is connected to the short-time thermal energy management unit 131 and the long-time thermal energy management unit 132, and the thermal coupling heat dissipation unit 133 includes a heat storage unit.

[0096] Wherein, O can be a positive integer, and each phase second subsystem can include the same number of thermal energy coupling modules. The short-time thermal energy management unit 131 and the long-time thermal energy management unit 132 can select independent heat dissipation or coupled heat dissipation with the heat storage unit.

[0097] In this way, in the heat dissipation management of the large-scale composite energy storage system, the thermal management distribution characteristics of the short-time energy storage in the high-rate mode can be combined with the thermal management distribution characteristics of the long-time energy storage in the low-rate mode, the distributed flow characteristics of the short-time energy storage liquid cooling and the long-time energy storage electrolyte can be played, and the thermal management requirements in different modes such as refrigeration heat dissipation and heat supply startup can be appropriately introduced. The comprehensive thermal management efficiency of the composite energy storage system is improved.

[0098] In an optional embodiment, as shown in Figure 3 The chemical energy coupling platform 14 includes three-phase fourth subsystems, each phase fourth subsystem includes P chemical energy coupling modules, and each chemical energy coupling module includes an electrolyte flow driving unit 141, an online capacity balancing unit 142, an online capacity repair unit 143, and an online capacity regeneration management unit 144.

[0099] The electrolyte flow driving unit 141 is connected to the chemical energy power supply unit 125 and the long-time energy storage power unit 122 of the electric energy coupling platform 12, and is used to drive the circulation flow of the electrolyte in the multiple long-time energy storage power units 122 according to the charge and discharge requirements of the long-time energy storage power unit 122, wherein the electrolyte flow driving unit 141 and the long-time energy storage power unit 122 are connected through an electrolyte pipeline;

[0100] The online capacity balancing unit 142 is connected to the electrolyte flow driving unit 141 and connected to the multiple long-time energy storage energy units of the long-time energy platform 15 through the distribution of the electrolyte pipeline, and is used to drive the capacity balancing distribution of the electrolyte in the multiple long-time energy storage energy units according to the capacity balancing requirements of the long-time energy platform 15;

[0101] The online capacity repair unit 143 is connected to the electrolyte flow drive unit 141 and is connected to multiple long-term energy storage units of the long-term energy platform 15 through the distribution of electrolyte pipelines. It is used to drive the electrolyte to distribute capacity repair in multiple long-term energy storage units according to the capacity repair requirements of the long-term energy platform 15.

[0102] The online capacity regeneration management unit 144 is connected to the electrolyte flow drive unit 141 and the capacity regeneration coupling platform 16, and is connected to multiple long-term energy storage units of the long-term energy platform 15 through the distribution of electrolyte pipelines. It is used to drive the capacity regeneration distribution of electrolyte in multiple long-term energy storage units according to the capacity regeneration requirements of the long-term energy platform 15.

[0103] Where P can be a positive integer, each phase fourth subsystem can include the same number of chemical energy coupling modules, and the charging and discharging requirements can be confirmed and issued by the energy management system (EMS).

[0104] In an optional embodiment, the chemical energy coupling platform 14 further includes a short-time energy storage safety management module connected to the short-time energy storage unit 121 of the electrical energy coupling platform 12, used to control the capacity of the short-time energy storage unit 121 according to safety operation requirements. These safety operation requirements can be confirmed and issued by the energy management system (EMS).

[0105] Thus, in the chemical energy management of large-scale composite energy storage systems, the capacity imbalance variation patterns of short-term energy storage in high-rate mode and long-term energy storage in low-rate mode can be combined. This leverages the different optimization characteristics of strong power coupling between short-term energy storage modules and strong energy coupling between long-term energy storage modules. By appropriately introducing capacity regeneration units containing recyclable materials, the online capacity balancing capability of the entire composite energy storage system can be optimized, the online capacity repair level can be improved, and ultimately, long-term online capacity regeneration of the composite energy storage system can be achieved, thereby improving the long-life safety and maintenance-free operation of the composite energy storage system.

[0106] In an alternative embodiment, such as Figure 3 As shown, the long-term energy platform 15 may include a three-phase fifth subsystem, each phase fifth subsystem including Q long-term energy storage units, each long-term energy storage unit including a positive electrode tank and a negative electrode tank;

[0107] The long-term energy storage unit is connected to the long-term energy storage power unit 122 of the electrical energy coupling platform 12 via the chemical energy coupling platform 14 to achieve online capacity balancing and online capacity repair.

[0108] The long-term energy storage unit is also connected to the capacity regeneration coupling platform 16 through the chemical energy coupling platform 14 to achieve online capacity regeneration.

[0109] For example, Q can be a positive integer, and each fifth subsystem can include the same number of long-duration energy storage units. The long-duration energy storage units can be connected to the long-duration energy storage power units 122 of the electrical energy coupling platform 12 through the chemical energy coupling platform 14, can be expanded according to the duration of energy storage, and can be completely decoupled from other long-duration energy storage power units 122. The long-duration energy storage units can participate in the implementation of online capacity balancing, online capacity repair, and online capacity regeneration through the connection of the chemical energy coupling platform 14, the long-duration energy storage power units 122 of the electrical energy coupling platform 12, and the capacity regeneration coupling platform 16.

[0110] In an optional embodiment, the long-duration energy module is also used to control the coupling processing of the thermal coupling heat dissipation units 133, the short-duration thermal energy management units 131, or the long-duration thermal energy management units 132 in the thermal energy coupling platform 13 according to the temperature and thermal energy distribution control demand, to perform optimized regulation and energy distribution.

[0111] In this way, the coupling of the system can be further improved, and the comprehensive thermal management efficiency of the composite energy storage system can be improved.

[0112] In an optional embodiment, as shown in Figure 3 The capacity regeneration coupling platform 16 can include R three-phase parallel AC-DC converters 161 and long-duration energy storage capacity regeneration units 162 corresponding to each of the AC-DC converters 161, where the AC-DC converters 161 are connected to the three-phase common ground side of the grid coupling platform 10; and the long-duration energy storage capacity regeneration units 162 include a regeneration anode tank, a regeneration cathode tank, and a regeneration power management unit for electrolysis.

[0113] The long-duration energy storage capacity regeneration units 162 are connected to the online capacity regeneration management unit 144 of the chemical energy coupling platform 14, are connected to the positive tank and the negative tank of the long-duration energy platform 15 through the distribution of the electrolyte pipeline, are used to guide the electrolyte that needs to be regenerated in the long-duration energy storage energy unit into the regeneration anode tank or the regeneration cathode tank of the long-duration energy storage capacity regeneration unit 162 when in the regeneration mode, and are used to complete the regeneration process of the electrolyte through electrolysis after adding the regeneration material through the AC-DC converter 161. The electrolyte after regeneration is controlled by the online capacity regeneration management unit 144 to flow to the positive tank and the negative tank from the regeneration anode tank and the regeneration cathode tank, respectively, to realize the system capacity regeneration distribution.

[0114] The structure of the regeneration power management unit is similar to that of the long-duration energy storage power unit 122 of the electrical energy coupling platform 12, and the two can be the same type of unit or different types of unit, which is not limited here. The regeneration power management unit can be connected to the online capacity regeneration management unit 144.

[0115] In an optional embodiment, the long-duration energy storage capacity regeneration unit 162 is further configured to control the AC end of the AC-DC converter 161 to maintain a zero voltage point, and the DC end to maintain an operating reference voltage in the electrolytic tank, and the regeneration anode tank and the regeneration cathode tank to maintain an active standby state when the capacity regeneration coupling platform 16 is not in the regeneration mode.

[0116] For example, the capacity regeneration coupling platform 16 can be determined to be in the regeneration mode according to the capacity self-checking result. If the capacity self-checking result is greater than a preset threshold value, it can be determined that the capacity of the long-duration energy storage device has a serious capacity problem and the problem can be solved by capacity regeneration. At this time, the capacity regeneration coupling platform 16 can be in the regeneration mode to realize capacity regeneration. If the capacity self-checking result is less than the preset threshold value, it can be determined that the capacity problem of the long-duration energy storage device is not serious and can be solved by capacity balancing or capacity repair. At this time, the capacity regeneration coupling platform 16 can not enter the regeneration mode to reduce the energy consumption of the system. Controlling the AC end of the AC-DC converter 161 to maintain a zero voltage point, and the DC end to maintain an operating reference voltage in the electrolytic tank, and the regeneration anode tank and the regeneration cathode tank to maintain an active standby state can quickly start to realize capacity regeneration when the capacity regeneration coupling platform 16 enters the regeneration mode.

[0117] In an optional embodiment, the large-scale composite energy storage system provided by the present disclosure can further comprise a controller, which can be configured to:

[0118] control the large-scale composite energy storage system to perform self-checking;

[0119] if the self-checking is passed, determine the power and energy scheduling demand of the alternating current power grid;

[0120] according to the scheduling demand, sequentially start the corresponding platform in the large-scale composite energy storage system;

[0121] after the grid coupling platform is started, start the target operating mode according to the grid monitoring state.

[0122] The self-checking includes periodic fault self-checking, non-periodic fault self-checking, capacity self-checking and temperature condition self-checking. The non-periodic fault self-checking is performed when the target parameter in the large-scale composite energy storage system reaches the corresponding reference threshold value. The target parameter can be the related data of the pre-set monitoring point, and the corresponding parameter threshold value can be pre-set according to the actual demand.

[0123] For example, the periodic detection can include periodic detection in two time scale ranges. A large time scale period is at least 1 more protection cycle periods, and the period length is determined according to protection requirements, generally in the range of milliseconds to seconds. A small time scale period is at least 1 more control cycle periods, and the period length is determined according to control requirements, generally in the range of microseconds to milliseconds. In addition, for time-sensitive key protection and control, a non-periodic interruption can be set to reduce the response delay.

[0124] In an optional embodiment, the controller can also be used for:

[0125] If the periodic fault self-check result or the non-periodic fault self-check result is abnormal, the fault point is isolated or removed;

[0126] If the periodic fault self-check result and the non-periodic fault self-check result are not abnormal, capacity self-check is performed.

[0127] In this way, the fault self-check of the large-scale composite energy storage system provided by the present disclosure can improve the safety and reliability of system operation, and when there is an abnormal monitoring point, the abnormal part can be processed in time to avoid affecting the overall operation of the system.

[0128] In an optional embodiment, the controller can also be used for:

[0129] If the capacity self-check result is abnormal, the large-scale composite energy storage system is controlled to perform online capacity balancing, repair, or capacity regeneration;

[0130] If the capacity self-check result is not abnormal, temperature condition self-check is performed.

[0131] For example, the capacity self-check result can be determined based on capacity balancing degree self-check and capacity health degree, to represent whether the system capacity is abnormal. If the capacity self-check result is abnormal, it can be determined that the system capacity is abnormal, and the abnormal problem can be solved by online capacity balancing, repair, or capacity regeneration. For example, the capacity self-check result can be represented by a numerical value, if the numerical value is greater than a first capacity threshold, it can be determined that the capacity abnormality is more serious, and the problem can be solved by online capacity regeneration, at this time the capacity regeneration coupling platform can be controlled to start; if the numerical value is less than the first capacity threshold and greater than a second capacity threshold, it can be determined that the capacity abnormality is relatively slight, and the problem can be solved by online capacity balancing and repair, at this time the online capacity repair unit and the online capacity balancing unit can be controlled to start; if the numerical value is less than the second capacity threshold, it can be determined that the system capacity is not abnormal, at this time, temperature condition self-check can be performed. In this way, the online capacity balancing capability of the entire composite energy storage system can be optimized, the online capacity repair level can be improved, and finally the long-term online capacity regeneration of the composite energy storage system can be realized, greatly improving the long-life safety and artificial maintenance level of the composite energy storage system.

[0132] In an optional embodiment, the controller can also be configured to:

[0133] If the temperature condition self-checking result is abnormal, the controller controls the thermal energy coupling platform to start;

[0134] If the temperature condition self-checking result is normal, the controller determines the dispatching requirement.

[0135] For example, if the temperature of the large-scale composite energy storage system is out of the preset temperature range, it can be determined that the temperature condition self-checking result is abnormal, and the thermal energy coupling platform can be controlled to start. In this way, the thermal management distribution characteristics of the short-time energy storage in the high-rate mode and the thermal management distribution characteristics of the long-time energy storage in the low-rate mode can be combined, the distributed flow characteristics of the short-time energy storage liquid cooling and the long-time energy storage electrolyte can be utilized, the heat storage technology can be appropriately introduced, the thermal management requirements in different modes such as refrigeration and heat dissipation and heat supply starting can be combined, and the comprehensive thermal management efficiency of the composite energy storage system can be improved.

[0136] If the temperature condition self-checking result is normal, it can be determined that the large-scale composite energy storage system passes the self-checking, and the controller can generate the dispatching requirement of the power and energy of the alternating current power grid according to the power grid monitoring state. The dispatching requirement of the power and energy can include a long-time energy requirement and / or a short-time energy requirement, and the determination of the dispatching requirement of the power and energy of the alternating current power grid can be implemented based on the technical solutions in the related art, which is not limited here.

[0137] In an optional embodiment, the controller can be configured to start the corresponding platforms in the large-scale composite energy storage system in sequence according to the dispatching requirement by the following method:

[0138] If the dispatching requirement includes a long-time energy requirement, the controller controls the long-time energy storage power unit of the electrical energy coupling platform, the electrolyte flow driving unit of the chemical energy coupling platform, the long-time energy platform, and the grid coupling platform to start in sequence.

[0139] If the dispatching requirement includes a short-time energy requirement, the controller controls the short-time energy storage unit of the electrical energy coupling platform and the grid coupling platform to start in sequence.

[0140] In this way, the fast frequency modulation capability of the short-time energy storage in the high-rate mode and the long-time peak regulation capability of the long-time energy storage in the low-rate mode can be combined, and the complementary characteristics of the short-time energy storage compensating for the power uncertainty of new energy fluctuation and the long-time energy storage balancing the seasonal energy uncertainty of new energy can be fully utilized.

[0141] In an optional embodiment, the power grid monitoring state is determined based on the impedance of the power grid.

[0142] For example, if the grid impedance is in a first preset range of impedance, the grid monitoring state can be determined as a strong grid monitoring state, and if the grid impedance is in a second preset range of impedance, the grid monitoring state can be determined as a weak grid monitoring state. When the grid monitoring state is determined as a weak grid monitoring state, it can be further determined whether the grid monitoring state is an off-grid state.

[0143] In an optional embodiment, the target operation mode includes a follow-grid structure and parameters in a grid-connected mode, a build-grid structure and parameters in the grid-connected mode, or a build-grid structure and parameters in an off-grid mode.

[0144] For example, the relationship between the grid state and the target operation mode can be preset, for example, if the grid is in a strong grid state, the follow-grid structure and parameters in the grid-connected mode can be started; if the grid is in a weak grid state, the build-grid structure and parameters in the grid-connected mode can be started; and if the grid is in an off-grid state, the build-grid structure and parameters in the off-grid mode can be started. In this way, the corresponding operation mode can be started based on the actual state of the grid, so as to improve the operation efficiency, stability, economy and safety of the system.

[0145] The preferred embodiments of the present disclosure are described in detail above with reference to the drawings, but the present disclosure is not limited to the specific details in the above-described embodiments. Within the technical concept of the present disclosure, various simple modifications can be made to the technical solutions of the present disclosure, and these simple modifications all belong to the protection scope of the present disclosure.

[0146] In addition, it should be noted that each specific technical feature described in the above specific embodiments can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, various possible combinations are not described again in the present disclosure.

[0147] In addition, any combination of various different embodiments of the present disclosure can also be made, as long as it does not deviate from the idea of the present disclosure, and it should also be considered as disclosed in the present disclosure.

Claims

1. A large-scale composite energy storage system, characterized in that, The system includes: The grid-connected coupling platform is connected to the AC grid through a grid interface unit to provide an energy interface for the large-scale composite energy storage system, so as to realize energy management control and grid status monitoring functions. An energy coupling platform is used to control short-term energy storage units, long-term energy storage power units, and long-term energy storage energy units in a long-term energy platform according to power and energy dispatch requirements, so as to realize power coupling conversion and energy flow control of the large-scale composite energy storage system. The dispatch requirements are determined based on the grid monitoring status and include long-term energy requirements and / or short-term energy requirements. The long-term energy storage unit includes a positive electrode tank and a negative electrode tank. A thermal energy coupling platform is used to control the temperature change and thermal energy distribution of the large-scale composite energy storage system based on the thermal management distribution characteristics of short-term energy storage and long-term energy storage. A chemical energy coupling platform is used to optimize the long-term energy platform and control the electrolyte flow state of the positive and negative electrode tanks in the long-term energy platform according to the control requirements of the long-term energy storage power unit in the electrical energy coupling platform, so that the long-term energy storage power unit can operate normally and realize the balance, recovery and regeneration control of the electrolyte. A capacity regeneration coupling platform is used to achieve capacity regeneration by coupling the grid-connected coupling platform according to the capacity regeneration requirements of the chemical energy coupling platform. The power coupling platform includes a three-phase second subsystem. Each phase of the second subsystem includes M power coupling modules, where M is a positive integer. Each power coupling module includes a short-time energy storage unit, a long-time energy storage power unit, a bidirectional DC-DC isolation unit, a short-time heat dissipation unit, a chemical energy power supply unit, a DC power interface, a short-time thermal energy interface, a long-time thermal energy interface, and a long-time chemical energy interface. The DC power interface is connected to the short-time energy storage unit and the grid-connected coupling platform, and is connected to the long-time energy storage power unit through the bidirectional DC-DC isolation unit. The short-time thermal energy interface terminal is connected to the short-time energy storage unit through the short-time heat dissipation unit for independent heat dissipation or connected to the short-time thermal energy interface terminals of other power coupling modules. The long-term thermal energy interface terminal connects the long-term thermal energy management unit of the thermal energy coupling platform to the long-term energy storage power unit for independent heat dissipation or to the long-term thermal energy interface terminal of other electrical energy coupling modules. The long-term chemical energy interface is connected to the chemical energy coupling platform, and the long-term chemical energy interface is connected to the short-term energy storage unit through the chemical energy power supply unit.

2. The large-scale composite energy storage system according to claim 1, characterized in that, The grid-connected coupling platform includes a three-phase first subsystem, and each phase of the first subsystem includes N cascaded DC-AC converters connected in series, where N is a positive integer. The three-phase common ground side of the grid-connected coupling platform is connected to the capacity regeneration coupling platform. The cascaded DC-AC converter is used to convert the energy provided by the AC grid into DC power and input the DC power to the power coupling platform, or to convert the DC power of the power coupling platform into AC power and input the energy to the AC grid; The grid-connected coupling platform is also used to convert the energy provided by the AC grid into AC power at a target voltage, and input the AC power at the target voltage to the capacity regeneration coupling platform.

3. The large-scale composite energy storage system according to claim 2, characterized in that, The thermal energy coupling platform includes a three-phase third subsystem. Each phase of the third subsystem includes O thermal energy coupling modules, where O is a positive integer. Each thermal energy coupling module includes a short-time thermal energy management unit, a long-time thermal energy management unit, and a thermal coupling heat dissipation unit. The short-time thermal energy management unit is connected to the short-time thermal energy interface of the power coupling platform; The long-term thermal energy management unit is connected to the long-term thermal energy interface of the power coupling platform; The thermally coupled heat dissipation unit is connected to the short-term thermal energy management unit and the long-term thermal energy management unit, and the thermally coupled heat dissipation unit includes a heat storage unit.

4. The large-scale composite energy storage system according to claim 3, characterized in that, The chemical energy coupling platform includes a three-phase fourth subsystem. Each phase of the fourth subsystem includes P chemical energy coupling modules, where P is a positive integer. Each chemical energy coupling module includes an electrolyte flow driving unit, an online capacity balancing unit, an online capacity repair unit, and an online capacity regeneration management unit. The electrolyte flow drive unit is connected to the chemical energy power supply unit and the long-term energy storage power unit of the power coupling platform. It is used to drive the electrolyte to circulate in multiple long-term energy storage power units according to the charging and discharging requirements of the long-term energy storage power units. The electrolyte flow drive unit and the long-term energy storage power units are connected by electrolyte pipelines. The online capacity balancing unit is connected to the electrolyte flow driving unit and is connected to multiple long-term energy storage units of the long-term energy platform through the distribution of the electrolyte pipeline. It is used to drive the capacity balancing distribution of the electrolyte in multiple long-term energy storage units according to the capacity balancing requirements of the long-term energy platform. The online capacity repair unit is connected to the electrolyte flow drive unit and is connected to multiple long-term energy storage units of the long-term energy platform through the distribution of the electrolyte pipeline. It is used to drive the electrolyte to distribute capacity repair in multiple long-term energy storage units according to the capacity repair requirements of the long-term energy platform. The online capacity regeneration management unit is connected to the electrolyte flow drive unit and the capacity regeneration coupling platform, and is connected to multiple long-term energy storage units of the long-term energy platform through the distribution of the electrolyte pipeline. It is used to drive the capacity regeneration distribution of the electrolyte in multiple long-term energy storage units according to the capacity regeneration requirements of the long-term energy platform.

5. The large-scale composite energy storage system according to claim 4, characterized in that, The chemical energy coupling platform also includes a short-time energy storage safety management module, which is connected to the short-time energy storage unit of the electrical energy coupling platform and is used to control the capacity of the short-time energy storage unit according to the safety operation requirements.

6. The large-scale composite energy storage system according to claim 4, characterized in that, The long-term energy platform includes a three-phase fifth subsystem, and each phase of the fifth subsystem includes Q long-term energy storage units, where Q is a positive integer. The long-term energy storage unit is connected to the long-term energy storage power unit of the electrical energy coupling platform through the chemical energy coupling platform to achieve online capacity balancing and online capacity repair. The long-term energy storage unit is also connected to the capacity regeneration coupling platform through the chemical energy coupling platform to achieve online capacity regeneration.

7. The large-scale composite energy storage system according to claim 6, characterized in that, The capacity regeneration coupling platform includes R three-phase parallel AC-DC converters and a long-term energy storage capacity regeneration unit corresponding to each AC-DC converter, wherein the AC-DC converters are connected to the three-phase common ground side of the grid-connected coupling platform; the long-term energy storage capacity regeneration unit includes a regeneration anode tank, a regeneration cathode tank, and a regeneration power management unit for realizing electrolysis. The long-term energy storage capacity regeneration unit is connected to the online capacity regeneration management unit of the chemical energy coupling platform. It is connected to the positive and negative electrode tanks of the long-term energy platform through the distribution of electrolyte pipelines. When in regeneration mode, it is used to introduce the electrolyte that needs to be regenerated from the long-term energy storage unit into the regeneration anode tank or regeneration cathode tank of the long-term energy storage capacity regeneration unit. After adding regenerative material, the electrolyte is electrolyzed by the AC-DC converter to complete the electrolyte regeneration process. After regeneration, the electrolyte flows from the regeneration anode tank and the regeneration cathode tank to the positive and negative electrode tanks respectively under the control of the online capacity regeneration management unit to realize the system capacity regeneration distribution.

8. The large-scale composite energy storage system according to claim 7, characterized in that, The long-term energy storage capacity regeneration unit is also used to control the AC terminal of the AC-DC converter to maintain a zero voltage potential and the DC terminal to maintain the reference voltage for operation in the electrolytic cell when it is not in regeneration mode, so that the regeneration anode tank and the regeneration cathode tank remain in an active standby state.

9. The large-scale composite energy storage system according to claim 1, characterized in that, The large-scale composite energy storage system also includes a controller, which is used for: The system controls the large-scale composite energy storage system to perform self-tests, which include periodic fault self-tests, non-periodic fault self-tests, capacity self-tests, and temperature condition self-tests. The non-periodic fault self-tests are performed when the target parameters in the large-scale composite energy storage system reach the corresponding reference thresholds. If the self-test passes, the power and energy scheduling requirements of the AC power grid are determined. According to the scheduling requirements, the corresponding platforms in the large-scale composite energy storage system are started sequentially; After the grid-connected coupling platform is started, the target operation mode is initiated based on the grid monitoring status.

10. The large-scale composite energy storage system according to claim 9, characterized in that, The controller is also used for: If the self-test results for periodic or non-periodic faults are abnormal, the fault point should be isolated or removed.

11. The large-scale composite energy storage system according to claim 9, characterized in that, The controller is also used for: If the self-test results for periodic faults and non-periodic faults are normal, then the capacity self-test is performed.

12. The large-scale composite energy storage system according to claim 11, characterized in that, The controller is also used for: If the capacity self-test result is abnormal, the system will be controlled to perform online capacity balancing, repair, or capacity regeneration. If the capacity self-test result is normal, then the temperature condition self-test is performed.

13. The large-scale composite energy storage system according to claim 12, characterized in that, The controller is also used for: If the temperature condition self-test result is abnormal, the thermal coupling platform will be started. If the temperature condition self-check result is normal, then the scheduling requirement is determined.

14. The large-scale composite energy storage system according to claim 9, characterized in that, The controller is used to sequentially start the corresponding platforms in the large-scale composite energy storage system according to the scheduling requirements in the following manner: If the scheduling requirement involves long-term energy demand, then the long-term energy storage power unit of the electrical energy coupling platform, the electrolyte flow drive unit of the chemical energy coupling platform, the long-term energy platform, and the grid-connected coupling platform are started sequentially. If the scheduling requirement involves short-term energy demand, then the short-term energy storage unit of the power coupling platform and the grid-connected coupling platform are started sequentially.

15. The large-scale composite energy storage system according to claim 9, characterized in that, The power grid monitoring status is determined based on the power grid impedance.

16. The large-scale composite energy storage system according to claim 9, characterized in that, The target operating mode includes the grid connection structure and parameters in grid-connected mode, the grid construction structure and parameters in grid-connected mode, or the grid construction structure and parameters in off-grid mode.

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