Energy storage system

Abstract

The utility model relates to an energy storage system which comprises a direct-current bin and an alternating-current bin, a plurality of battery clusters and a plurality of corresponding fusion type energy storage converters are arranged in the direct-current bin, a transformer is arranged in an alternating-current box, and the output ends of the battery clusters are connected with the direct-current sides of the fusion type energy storage converters in a one-to-one correspondence mode. According to the integrated energy storage system, the battery clusters are not directly connected in parallel any more, the problem of circulating current between the battery clusters in an existing energy storage system is solved, the efficiency of the energy storage system can be effectively improved, the service life of the energy storage system can be effectively prolonged, and the availability of a power station is improved; through fusion design of functions and components of an existing battery cluster high-voltage box and an energy storage converter, an alternating current bin is not provided with the energy storage converter any more, the occupied area of an energy storage power station is reduced, the number of total components can be effectively reduced through the fusion type energy storage converter, and therefore the total cost of an energy storage system is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of new energy, in particular to a kind of energy storage system. BACKGROUND

[0002] Current energy storage power station has high requirement on initial cost, so most power stations use centralized energy storage system.

[0003] The centralized energy storage system in prior art includes DC bin and AC bin, multiple battery clusters are arranged in the DC bin, and high-voltage box (BMS master control and protection devices are generally arranged in the high-voltage box) is arranged in the AC bin, centralized energy storage converter (power MW level) and step-up transformer are arranged in the AC bin, multiple battery clusters are connected in parallel and connected to the power grid through centralized energy storage converter inversion, because multiple battery clusters are connected in parallel, there is a situation that the voltage of each battery cluster is not balanced, which causes a circulating current problem between the parallel battery clusters, seriously affecting the efficiency and service life of the energy storage system, and if the centralized energy storage converter fails, the centralized energy storage converter needs to be cut off, that is, the power of MW level is cut off, which will seriously affect the availability of the power station. CONTENT OF THE UTILITY MODEL

[0004] To solve the above technical problems, the purpose of the present application is to provide an energy storage system, the energy storage system provided by the present application can effectively solve the circulating current problem existing in the existing energy storage system, can effectively improve the efficiency and service life of the energy storage system, can effectively improve the availability of the power station, can reduce the required land area of the energy storage power station, and can reduce the total cost of the energy storage system.

[0005] The technical scheme provided by the present application is as follows:

[0006] An energy storage system, comprising: a DC bin and an AC bin, multiple battery clusters and corresponding multiple fusion-type energy storage converters are arranged in the DC bin, and a transformer is arranged in the AC bin;

[0007] The output end of each battery cluster is connected to the DC side of each fusion-type energy storage converter one by one;

[0008] The AC side of each fusion-type energy storage converter in the DC bin is connected to the low-voltage side of the transformer in the AC bin in parallel;

[0009] The high-voltage side of the transformer is connected to the power grid.

[0010] Optionally, each fusion-type energy storage converter comprises: a DC input unit, an inversion unit, a grid-connected filter unit, an auxiliary power supply unit, a BMS master control and a PCS controller;

[0011] The output end of the battery cluster is connected to the input end of the DC input unit;

[0012] The output terminal of the DC input unit is connected to the input terminal of the inverter unit;

[0013] The output terminal of the inverter unit is connected to the input terminal of the grid-connected filter unit;

[0014] The auxiliary power supply unit is used to supply power to the PCS controller, the BMS master controller, and the BMS slave controller in the battery cluster.

[0015] Optionally, the DC input unit includes: a disconnecting switch, a positive line relay, a negative line relay, a fuse, a precharge relay, a precharge resistor, a DC voltage sensor, and a DC current sensor;

[0016] The positive output terminal of the battery cluster is connected to the first terminal of the disconnect switch;

[0017] The second terminal of the disconnecting switch is connected to the first terminal of the positive line relay, the first terminal of the precharge relay, and the first terminal of the DC voltage sensor.

[0018] The second terminal of the precharge relay is connected to the first terminal of the precharge resistor;

[0019] The second terminal of the pre-charge resistor and the second terminal of the positive line relay are connected to the positive input terminal of the inverter unit;

[0020] The negative output terminal of the battery cluster is connected to the third terminal of the disconnect switch;

[0021] The fourth terminal of the disconnecting switch is connected to the first terminal of the fuse;

[0022] The second end of the fuse is connected to the first end of the DC current sensor;

[0023] The second terminal of the DC current sensor is connected to the second terminal of the DC voltage sensor and the first terminal of the negative line relay;

[0024] The second terminal of the negative line relay is connected to the negative input terminal of the inverter unit.

[0025] Optionally, the inverter unit includes a first DC capacitor, a second DC capacitor, and a three-phase inverter;

[0026] The first terminal of the first DC capacitor is connected to the second terminal of the pre-charge resistor, the second terminal of the positive line relay, and the positive input terminal of the three-phase inverter.

[0027] The second terminal of the first DC capacitor is connected to the zero input terminal of the three-phase inverter, the first terminal of the second DC capacitor, and the first input terminal of the grid-connected filter unit.

[0028] a second end of the second DC capacitor is connected with a second end of the negative line relay and a negative input end of the three-phase inverter;

[0029] an output end of the three-phase inverter is connected with a second input end of the grid-connected filter unit;

[0030] the PCS controller is connected with a control end of the three-phase inverter.

[0031] Optionally, the auxiliary power supply unit simultaneously takes high voltage from an output end of the battery cluster, a grid side, and the first DC capacitor and the second DC capacitor.

[0032] Optionally, a plurality of protection devices are arranged in the DC compartment.

[0033] Each of the protection devices is arranged between each of the fusion-type energy storage converters and the transformer, and the protection device is used to isolate the faulty fusion-type energy storage converter from the grid and other normal fusion-type energy storage converters when a single fusion-type energy storage converter fails.

[0034] Optionally, the BMS master control is connected with the PCS controller through a CAN communication interface, and the BMS master control is connected with a BMS slave control in the battery cluster through the CAN communication interface.

[0035] Optionally, a local controller is arranged in the DC compartment.

[0036] The local controller is connected with each of the PCS controllers through an Ethernet interface or a CAN interface.

[0037] The local controller communicates with an energy management system EMS.

[0038] Optionally, a BMS master control is arranged in the DC compartment.

[0039] The BMS master control is connected with each of the BMS master controls through an Ethernet interface or a CAN interface.

[0040] The BMS master control communicates with the energy management system EMS.

[0041] Compared with the prior art, the energy storage system provided by the application comprises a direct current bin and an alternating current bin, a plurality of battery clusters and a plurality of corresponding fusion type energy storage converters are arranged in the direct current bin, a transformer is arranged in the alternating current bin, the output end of each battery cluster is connected in one-to-one correspondence with the direct current side of each fusion type energy storage converter, and the alternating current sides of the fusion type energy storage converters in the direct current bin are connected to the low voltage side of the transformer in the alternating current bin after being connected in parallel. In the application, the battery clusters are no longer directly connected in parallel, the circulating current problem between the battery clusters in the existing energy storage system is solved, the efficiency and service life of the energy storage system can be effectively improved, and the availability of the power station is improved. By fusing the functions and components of the existing battery cluster high voltage box and the energy storage converter, there is no energy storage converter in the alternating current bin, the land occupation of the energy storage power station can be reduced, and the fusion type energy storage converter can effectively reduce the number of total components, thereby reducing the total cost of the energy storage system. BRIEF DESCRIPTION OF DRAWINGS

[0042] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the application, and other drawings can be obtained by those skilled in the art without creative effort.

[0043] Figure 1 It is a circuit diagram of the centralized energy storage system in the prior art.

[0044] Figure 2 It is a structure block diagram of the energy storage system provided in the embodiments of the application.

[0045] Figure 3 It is a circuit diagram of the energy storage system provided in the embodiments of the application.

[0046] Figure 4-1 It is a schematic diagram of the direct current fault protection circuit in the high voltage box in the direct current bin in the prior art.

[0047] Figure 4-2 It is a schematic diagram of the pre-charge and direct current fault protection circuit in the centralized energy storage converter in the alternating current bin in the prior art.

[0048] Figure 4-3 It is a schematic diagram of the direct current input unit, the PCS controller, the BMS master control and the auxiliary power supply unit in the fusion type energy storage converter provided in the embodiments of the application.

[0049] Figure 5 It is a communication architecture schematic diagram of the energy storage system provided in the embodiments of the application.

[0050] 100-battery cluster; 200-fusion energy storage converter; 300-transformer; 400-protective device; 500-local controller; 600-BMS master controller; 700-energy management system EMS;

[0051] 110-BMS slave;

[0052] 210-dc input unit; 220-inverter unit; 230-grid-connected filter unit; 240-assisted power supply unit; 250-BMS master; 260-PCS controller;

[0053] QS1-disconnector; K1-positive line relay; K2-negative line relay; FU1-fuse; K3-precharge relay; R1-precharge resistor; 211-dc voltage sensor; 212-dc current sensor; K4-fourth relay;

[0054] C1-first dc capacitor; C2-second dc capacitor; 221-three-phase inverter. DETAILED DESCRIPTION

[0055] In order to make the technical personnel in the art better understand the technical solutions in the present application, the technical solutions in the embodiments of the present application will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present application, not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor are within the scope of protection of the present application.

[0056] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly disposed on the other element; when an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0057] It should be understood that the terms "length", "width", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0058] In addition, the terms "first", "second", etc. are used only for descriptive purposes and do not connote or imply relative importance or an ordering between or among the indicated technical features. Thus, a feature defined with "first", "second", etc. can include one or more of the features implicitly or explicitly.

[0059] It should be noted that the structures, proportions, sizes, etc. shown in the drawings of the present disclosure are merely used to illustrate the content disclosed in the present disclosure for understanding and reading by those skilled in the art, and do not define the limiting conditions for the implementation of the present disclosure, and therefore do not have technical significance. Any modification of the structure, change of the proportional relationship or adjustment of the size, without affecting the effects and purposes that can be achieved by the present disclosure, should still fall within the scope of the technical content disclosed by the present disclosure.

[0060] Figure 1 A circuit diagram of a centralized energy storage system in the prior art is shown, and a plurality of battery clusters and a high-voltage box are arranged in the direct current bin of the existing centralized energy storage system, and the high-voltage box is arranged with a BMS master control, a direct current fault protection circuit and an auxiliary power supply, Figure 4-1 The direct current fault protection circuit in the high-voltage box in the direct current bin in the prior art includes disconnector, positive line direct current relay, negative line direct current relay, fuse, voltage equalization control relay, voltage equalization resistor, direct current voltage sensor and direct current current sensor, and the centralized energy storage converter and the step-up transformer are arranged in the alternating current bin, and the centralized energy storage converter includes pre-charging and direct current fault protection circuit, inverter module, grid-connected filter module, auxiliary power supply and PCS controller, Figure 4-2 The pre-charging and direct current fault protection circuit in the centralized energy storage converter in the alternating current bin in the prior art includes positive line relay, pre-charging relay, pre-charging resistor, direct current voltage sensor and direct current current sensor, wherein the BMS (Battery Management System, battery management system) is a master controller in the battery management system, and the PCS (Power Conversion System, energy storage converter) is a controller in the energy storage converter.

[0061] As Figure 2As shown, the embodiment of the application provides a kind of energy storage system, comprising: direct current warehouse and alternating current warehouse, multiple battery clusters 100 and corresponding multiple fusion energy storage converters 200 are arranged in direct current warehouse, transformer 300 is arranged in alternating current warehouse;The output of each battery cluster 100 is connected with the direct current side of each fusion energy storage converter 200 one by one;The alternating current side of each fusion energy storage converter 200 in direct current warehouse is connected with the low voltage side of transformer 300 in alternating current warehouse after parallel connection;The high voltage side of transformer 300 is connected with power grid.

[0062] In the embodiment, multiple can be N, N is greater than 1 positive integer, specifically, N can be 12, by setting the number of battery clusters 100 corresponding multiple fusion energy storage converters 200, so that each battery cluster 100 is connected with one fusion energy storage converter 200, each battery cluster 100 is no longer directly connected in parallel, so that there is no circulating current problem existing in existing centralized energy storage system, which can effectively improve the efficiency and life of energy storage system;And if single fusion energy storage converter 200 fails, only need to cut off the single fusion energy storage converter 200 that fails, which can effectively improve the availability of power station.

[0063] In the embodiment, since there are repeated devices in the high voltage box in the existing direct current warehouse and the centralized energy storage converter in alternating current warehouse, by fusing the devices in the high voltage box in the prior art in the direct current warehouse and the devices in the centralized energy storage converter in the alternating current warehouse, the repeated devices are deleted, to obtain the fusion energy storage converter 200 after fusion, which can effectively reduce the number of total components, can effectively reduce the total cost of energy storage system, in addition, by setting the fusion energy storage converter 200 in the direct current warehouse, only transformer 300 is arranged in the original alternating current warehouse, without setting energy storage converter in alternating current warehouse, which can effectively reduce the floor area of alternating current warehouse, and further can reduce the floor area of energy storage power station, which can further reduce the cost.

[0064] Compared with the prior art, the energy storage system provided by the application comprises: a direct current bin and an alternating current bin, a plurality of battery clusters 100 and a plurality of corresponding fusion energy storage converters 200 are arranged in the direct current bin, a transformer 300 is arranged in the alternating current bin, the output end of each battery cluster 100 is connected to the direct current side of each fusion energy storage converter 200 in one-to-one correspondence, and the alternating current side of each fusion energy storage converter 200 in the direct current bin is connected to the low-voltage side of the transformer 300 in the alternating current bin after being connected in parallel. In the application, each battery cluster 100 is no longer directly connected in parallel, the problem of circulating current between the battery clusters 100 in the existing energy storage system is solved, the efficiency and service life of the energy storage system can be effectively improved, and the availability of the power station is improved. By fusing the existing high-voltage box of the battery cluster 100 with the functions and components of the energy storage converter, there is no longer an energy storage converter in the alternating current bin, the floor area occupied by the energy storage power station can be reduced, and the fusion energy storage converter 200 can effectively reduce the number of total components, thereby reducing the total cost of the energy storage system.

[0065] As shown in Figure 3 , as an embodiment, each fusion energy storage converter 200 in the embodiment of the application comprises: a direct current input unit 210, an inverter unit 220, a grid-connected filter unit 230, an auxiliary power supply unit 240, a BMS master control 250 and a PCS controller 260; the output end of the battery cluster 100 is connected to the input end of the direct current input unit 210; the output end of the direct current input unit 210 is connected to the input end of the inverter unit 220; the output end of the inverter unit 220 is connected to the input end of the grid-connected filter unit 230; the auxiliary power supply unit 240 is used to supply power to the PCS controller 260, the BMS master control 250 and the BMS slave control 110 in the battery cluster 100.

[0066] In the embodiment, a plurality of battery packs and one BMS slave control can be arranged in the battery cluster 100; by fusing the direct current fault protection circuit in the high-voltage box in the direct current bin in the prior art with the devices in the pre-charging and direct current fault protection circuit in the centralized energy storage converter in the alternating current bin, redundant devices are deleted, and the fused direct current input unit 210 is obtained, as shown in Figure 4-1 and Figure 4-2 Since there is an auxiliary power supply in the high-voltage box in the direct current bin in the prior art and there is also an auxiliary power supply in the centralized energy storage converter in the alternating current bin, as shown in Figure 4-3 , only one auxiliary power supply, i.e., the auxiliary power supply unit 240, is needed to supply power to the PCS controller 260, the BMS master control 250 and the BMS slave control 110 in the battery cluster 100, which can effectively reduce the number of total components, thereby reducing the total cost of the energy storage system.

[0067] In this embodiment, the BMS master 250 is configured to perform battery charging and discharging control and protection according to the detected voltage, current, temperature and power of the battery cluster 100, and the PCS controller 260 is configured to perform function control on the energy storage converter according to the received voltage, current, temperature and received instructions.

[0068] As shown in Figure 3 As an embodiment, the direct current input unit 210 includes an isolating switch QS1, a positive line relay K1, a negative line relay K2, a fuse FU1, a pre-charge relay K3, a pre-charge resistor R1, a direct current voltage sensor 211 and a direct current current sensor 212. The positive output end of the battery cluster 100 is connected to the first end of the isolating switch QS1. The second end of the isolating switch QS1 is connected to the first end of the positive line relay K1, the first end of the pre-charge relay K3 and the first end of the direct current voltage sensor 211. The second end of the pre-charge relay K3 is connected to the first end of the pre-charge resistor R1. The second end of the pre-charge resistor R1 and the second end of the positive line relay K1 are connected to the positive input end of the inverter unit 220. The negative output end of the battery cluster 100 is connected to the third end of the isolating switch QS1. The fourth end of the isolating switch QS1 is connected to the first end of the fuse FU1. The second end of the fuse FU1 is connected to the first end of the direct current current sensor 212. The second end of the direct current current sensor 212 is connected to the second end of the direct current voltage sensor 211 and the first end of the negative line relay K2. The second end of the negative line relay K2 is connected to the negative input end of the inverter unit 220.

[0069] As shown in Figure 4-1 and Figure 4-2 As shown in Figure 4-3 In the prior art, the direct current fault protection circuit in the high voltage box in the direct current warehouse includes an isolating switch, a positive line direct current relay, a negative line direct current relay, a fuse, a voltage equalization control relay, a voltage equalization resistor, a direct current voltage sensor and a direct current current sensor. In the prior art, the pre-charge and direct current fault protection circuit in the centralized energy storage converter in the alternating current warehouse includes a positive line relay, a pre-charge relay, a pre-charge resistor, a direct current voltage sensor and a direct current current sensor. It can be seen that the direct current voltage sensor and the direct current current sensor are repeated devices, the positive line direct current relay and the positive line relay have the same function, the voltage equalization control relay and the pre-charge relay have the same or similar function, and the voltage equalization resistor and the pre-charge resistor have the same or similar function. In this scheme, the devices in the direct current fault protection circuit in the high voltage box in the direct current warehouse and the pre-charge and direct current fault protection circuit in the centralized energy storage converter in the alternating current warehouse are fused, and the repeated devices are deleted. Specifically, one direct current voltage sensor, one direct current current sensor, one positive line direct current relay, one voltage equalization control relay and one voltage equalization resistor can be deleted.As shown, the DC input unit 210 is obtained after fusion, including the disconnector QS1, the positive line relay K1, the negative line relay K2, the fuse FU1, the pre-charge relay K3, the pre-charge resistor R1, the DC voltage sensor 211 and the DC current sensor 212, so that the DC input unit 210 fuses the DC fault protection function of the DC fault protection circuit in the high-voltage box in the DC compartment in the prior art and the pre-charge and DC fault protection function of the pre-charge and DC fault protection circuit in the centralized energy storage converter in the AC compartment.

[0070] As shown in the figure, Figure 3 As an embodiment, in the embodiment of the application, the inverter unit 220 includes a first DC capacitor C1, a second DC capacitor C2 and a three-phase inverter 211; the first end of the first DC capacitor C1 is connected with the second end of the pre-charge resistor R1, the second end of the positive line relay K1 and the positive input end of the three-phase inverter 211; the second end of the first DC capacitor C1 is connected with the zero input end of the three-phase inverter 211, the first end of the second DC capacitor C2 and the first input end of the grid-connected filter unit 230; the second end of the second DC capacitor C2 is connected with the second end of the negative line relay K2 and the negative input end of the three-phase inverter 211; the output end of the three-phase inverter 211 is connected with the second input end of the grid-connected filter unit 230; the PCS controller 260 is connected with the control end of the three-phase inverter 211.

[0071] In the embodiment, through the inverter unit 220 including the first DC capacitor C1, the second DC capacitor C2 and the three-phase inverter 211, the input DC power can be effectively converted into AC power.

[0072] In the embodiment of the application, the grid-connected filter unit can include a first filter inductor, a second filter inductor and a filter capacitor, the second end of the first DC capacitor is connected with the zero input end of the three-phase inverter unit, the first end of the second DC capacitor and the first end of the filter capacitor, the output end of the three-phase inverter unit is connected with the first end of the first filter inductor, the second end of the first filter inductor is connected with the second end of the filter capacitor and the first end of the second filter inductor, the second end of the second filter inductor is connected with the low-voltage side of the transformer, and the specific connection mode of the devices in the grid-connected filter unit is not shown in the figure, and the grid-connected filter unit can also have other implementation schemes.

[0073] As an embodiment, in the embodiment of the application, the auxiliary power supply unit 240 simultaneously takes high-voltage power from the output end of the battery cluster 100, the grid side and the first DC capacitor C1 and the second DC capacitor C2.

[0074] In the embodiment, the auxiliary power supply unit 240 has stronger power supply reliability by simultaneously taking high-voltage power from the output end of the battery cluster 100, the power grid side, and the first DC capacitor C1 and the second DC capacitor C2.

[0075] As shown in Figure 3 As an implementation form, in the embodiment, the DC warehouse further comprises a plurality of protection devices 400, each of which is arranged between the fusion energy storage converter 200 and the transformer 300, and is used to isolate the faulty fusion energy storage converter from the power grid and other normal fusion energy storage converters when a single fusion energy storage converter 200 fails.

[0076] In the embodiment, the protection device 400 can be a circuit breaker or a fuse FU1, and each phase output end of the three-phase inverter 211 in the fusion energy storage converter 200 can be configured with one protection device 400. Specifically, the protection device 400 is arranged between the second filter inductor L2 and the transformer 300, and a fourth relay K4 can be further arranged between the second filter inductor L2 and the protection device 400. By arranging the protection device 400 between the fusion energy storage converter 200 and the transformer 300, the faulty fusion energy storage converter can be effectively isolated from the power grid and other normal fusion energy storage converters when a single fusion energy storage converter 200 fails.

[0077] As shown in Figure 5 As an implementation form, in the embodiment, the BMS master control 250 is connected with the PCS controller 260 through a CAN communication interface, and the BMS master control 250 is connected with the BMS slave control 110 in the battery cluster through the CAN communication interface.

[0078] In the embodiment, the BMS master control 250 and the PCS controller 260 can be independent single boards or can be functionally integrated, and the BMS master control 250 and the PCS controller 260 directly interact information through the communication interface.

[0079] As shown in Figure 5 As an implementation form, in the embodiment, the DC warehouse further comprises a local controller 500, the local controller 500 is connected with each PCS controller 260 through an Ethernet interface or a CAN interface, and the local controller 500 communicates with an energy management system EMS 700.

[0080] In the embodiment, the local controller 500 and the PCS controller 260 can be configured according to the system condition, the local controller 500 and each PCS controller 260 can communicate through the Ethernet to realize the storage control instruction issuing and state uploading, and the local controller 500 and the energy management system EMS 700 can communicate through the Ethernet.

[0081] As shown in Figure 5 As an embodiment, the BMS master control 600 is further arranged in the direct current bin, the BMS master control 600 is connected with each BMS master control 250 through the Ethernet interface or the CAN interface, and the BMS master control 600 communicates with the energy management system EMS 700.

[0082] In the embodiment, the BMS master control 600 and each BMS master control 250 can realize the battery management instruction issuing and state uploading through the Ethernet, and the BMS master control 600 and the energy management system can communicate through the Ethernet.

[0083] The embodiments in the specification are described in a progressive manner, and each embodiment focuses on the same or similar parts of other embodiments.

[0084] The other embodiments are different from each other, and the same or similar parts of each embodiment can be referred to.

[0085] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present application. Various modifications to the embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An energy storage system, characterized in that, include: The system includes a DC compartment and an AC compartment. The DC compartment contains multiple battery clusters and corresponding multiple integrated energy storage converters, while the AC compartment contains a transformer. The output terminal of each battery cluster is connected to the DC side of each integrated energy storage converter in a one-to-one correspondence. The AC sides of each of the integrated energy storage converters in the DC compartment are connected in parallel and then connected to the low-voltage side of the transformer in the AC compartment. The high-voltage side of the transformer is connected to the power grid.

2. The energy storage system according to claim 1, characterized in that, Each of the aforementioned integrated energy storage converters includes: a DC input unit, an inverter unit, a grid-connected filter unit, an auxiliary power supply unit, a BMS main controller, and a PCS controller; The output terminal of the battery cluster is connected to the input terminal of the DC input unit; The output terminal of the DC input unit is connected to the input terminal of the inverter unit; The output terminal of the inverter unit is connected to the input terminal of the grid-connected filter unit; The auxiliary power supply unit is used to supply power to the PCS controller, the BMS master controller, and the BMS slave controller in the battery cluster.

3. The energy storage system according to claim 2, characterized in that, The DC input unit includes: a disconnect switch, a positive line relay, a negative line relay, a fuse, a precharge relay, a precharge resistor, a DC voltage sensor, and a DC current sensor; The positive output terminal of the battery cluster is connected to the first terminal of the disconnect switch; The second terminal of the disconnecting switch is connected to the first terminal of the positive line relay, the first terminal of the precharge relay, and the first terminal of the DC voltage sensor. The second terminal of the precharge relay is connected to the first terminal of the precharge resistor; The second terminal of the pre-charge resistor and the second terminal of the positive line relay are connected to the positive input terminal of the inverter unit; The negative output terminal of the battery cluster is connected to the third terminal of the disconnect switch; The fourth terminal of the disconnecting switch is connected to the first terminal of the fuse; The second end of the fuse is connected to the first end of the DC current sensor; The second terminal of the DC current sensor is connected to the second terminal of the DC voltage sensor and the first terminal of the negative line relay; The second terminal of the negative line relay is connected to the negative input terminal of the inverter unit.

4. The energy storage system according to claim 3, characterized in that, The inverter unit includes a first DC capacitor, a second DC capacitor, and a three-phase inverter; The first terminal of the first DC capacitor is connected to the second terminal of the pre-charge resistor, the second terminal of the positive line relay, and the positive input terminal of the three-phase inverter. The second terminal of the first DC capacitor is connected to the zero input terminal of the three-phase inverter, the first terminal of the second DC capacitor, and the first input terminal of the grid-connected filter unit. The second terminal of the second DC capacitor is connected to the second terminal of the negative line relay and the negative input terminal of the three-phase inverter; The output terminal of the three-phase inverter is connected to the second input terminal of the grid-connected filter unit; The PCS controller is connected to the control terminal of the three-phase inverter.

5. The energy storage system according to claim 4, characterized in that, The auxiliary power supply unit simultaneously draws high-voltage power from the output terminal of the battery cluster, the grid side, and the first and second DC capacitors.

6. The energy storage system according to claim 1, characterized in that, The DC compartment is also equipped with multiple protection devices; Each of the aforementioned protection devices is installed between each of the integrated energy storage converters and the transformer. The protection devices are used to isolate the faulty integrated energy storage converter from the power grid and other normal integrated energy storage converters when a single integrated energy storage converter fails.

7. The energy storage system according to claim 2, characterized in that, The BMS master controller is connected to the PCS controller via a CAN communication interface, and the BMS master controller is connected to the BMS slave controller in the battery cluster via a CAN communication interface.

8. The energy storage system according to claim 7, characterized in that, The DC compartment is also equipped with a local controller; The local controller is connected to each of the PCS controllers via an Ethernet interface or a CAN interface. The local controller communicates with the energy management system (EMS).

9. The energy storage system according to claim 8, characterized in that, The DC compartment is also equipped with a BMS central control system; The BMS master controller is connected to each BMS master controller via an Ethernet interface or a CAN interface; The BMS central control unit communicates with the EMS energy management system.

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