Energy storage system and energy storage method

Abstract

The invention provides an energy storage system and an energy storage method. The energy storage system comprises a battery pack, and the battery pack comprises a plurality of battery cells, a plurality of first switch pieces and a plurality of second switch pieces; the plurality of battery cells are sequentially connected in series; the plurality of first switch pieces are in one-to-one correspondence with the plurality of battery cells, and the first switch pieces are connected in series between positive electrodes and negative electrodes of the battery cells; the second switch piece is connected in series between two adjacent battery cells, and the second switch piece is arranged between the first switch piece and the positive electrode or the negative electrode of the battery cell; the battery pack is configured in such a manner that when at least one of the plurality of battery cells is a failed battery cell, at least one second switching element connected with the failed battery cell is disconnected, so that the failed battery cell is disconnected from another adjacent battery cell; the first switch piece corresponding to the failure battery cell is closed; and when the failure battery cell is detected, the failure battery cell is disconnected, and the battery cells on the two sides of the failure battery cell are short-circuited, so that the influence of the failure battery cell on the battery pack is reduced, and the recycling of the battery pack is realized.

Description

Technical Field

[0001] The present application belongs to the technical field of battery recycling, and in particular, relates to an energy storage system and an energy storage method. Background Art

[0002] With the rapid development of new energy vehicles, energy storage systems and other fields, battery technology has been widely used. However, as the battery pack is used for a longer time, some cells will gradually fail due to increased internal resistance and capacity attenuation, resulting in the performance of the entire battery pack being reduced and unable to meet the original design requirements, thus facing retirement.

[0003] In the process of handling retired batteries, due to the complex internal structure of the battery pack, if each battery cell needs to be inspected in detail and the failed battery cell needs to be replaced, it will not only be costly, but also may damage other batteries that have not failed or the entire battery pack structure due to improper operation during the disassembly process. If the entire battery pack is directly screened and eliminated as a whole, it may still contain a large number of batteries that have not completely failed. The remaining capacity and performance of these batteries still have certain utilization value. Direct elimination will cause serious waste of resources.

[0004] Therefore, how to improve the recycling rate of batteries is a problem that technicians in this field currently need to solve. Summary of the invention

[0005] The purpose of the present application is to provide an energy storage system and an energy storage method, aiming to solve the problem of improving the recycling rate of batteries in traditional technologies.

[0006] A first aspect of an embodiment of the present application provides an energy storage system, the energy storage system comprising a battery pack, the battery pack comprising:

[0007] A plurality of battery cells, wherein the plurality of battery cells are sequentially arranged in series;

[0008] A plurality of first switch elements, corresponding one to one with the plurality of battery cells, and the first switch elements are connected in series between the positive electrode and the negative electrode of the battery cell;

[0009] A plurality of second switch elements, wherein the second switch elements are arranged in series between two adjacent battery cells, and the second switch elements are arranged between the first switch element and the positive electrode or the negative electrode of the battery cell;

[0010] The battery pack is configured such that when at least one battery cell among the multiple battery cells is a failed battery cell, at least one of the second switch components connected to the failed battery cell is disconnected to disconnect the failed battery cell from another adjacent battery cell; and the first switch component corresponding to the failed battery cell is closed to short-circuit the positive and negative electrodes of the failed battery cell, thereby short-circuiting the two adjacent battery cells of the failed battery cell.

[0011] In some embodiments of the present application, the failed battery cell is arranged between two of the battery cells, and the failed battery cell has two second switch elements for connecting the two battery cells; wherein, the battery pack is configured so that when at least one battery cell among the multiple battery cells is a failed battery cell, the two second switch elements connecting the failed battery cells are disconnected.

[0012] In some embodiments of the present application, the energy storage system further includes a detection module, and the detection module is used to perform battery cell leakage detection, chassis sealing detection or temperature detection on the energy storage system.

[0013] In some embodiments of the present application, the second switch element includes at least one of a copper busbar, an aluminum busbar, a power wiring harness, or a nickel sheet.

[0014] In some embodiments of the present application, there are multiple battery packs, and the multiple battery packs are connected in series to form a battery cluster, and the battery cluster is connected to a DC bus; the energy storage system also includes a first circuit breaker and a first control unit, the first circuit breaker is arranged between the battery cluster and the DC bus, and the first control unit is used to control the on / off of the first circuit breaker.

[0015] In some embodiments of the present application, the energy storage system further includes multiple first coupling control units, the number of the battery clusters is multiple, the multiple first coupling units correspond one-to-one to the multiple battery clusters, and the multiple battery clusters are connected in parallel to the DC bus through the multiple first coupling units.

[0016] In some embodiments of the present application, there are multiple battery packs, and the multiple battery packs are connected in series to form a battery cluster, and the battery cluster is connected to an AC bus; the energy storage system also includes a second circuit breaker and a second control unit, the second circuit breaker is arranged between the battery cluster and the AC bus, and the second control unit is used to control the on / off of the second circuit breaker.

[0017] In some embodiments of the present application, the energy storage system further includes multiple second coupling control units, the number of the battery clusters is multiple, the multiple second coupling units correspond one-to-one to the multiple battery clusters, and the multiple battery clusters are connected in parallel to the AC bus through the multiple second coupling units.

[0018] In a second aspect, the present application also provides an energy storage method, which is applied to the above-mentioned energy storage system.

[0019] In some embodiments of the present application, the energy storage system includes a control module and a battery cluster, and the control module is used to detect the battery cluster and control the charging and discharging parameters of the battery cluster according to the detection data.

[0020] Compared with the prior art, the embodiments of the present invention have the following beneficial effects: in the above-mentioned energy storage system and energy storage method, the energy storage system includes a battery pack, the battery pack includes a plurality of battery cells, a plurality of first switch elements and a plurality of second switch elements; the plurality of battery cells are arranged in series in sequence; the plurality of first switch elements correspond to the plurality of battery cells one by one, and the first switch element is connected in series between the positive electrode and the negative electrode of the battery cell; the second switch element is arranged in series between two adjacent battery cells, and the second switch element is arranged between the first switch element and the positive electrode or the negative electrode of the battery cell; the battery pack is configured such that when at least one battery cell among the plurality of battery cells is a failed battery cell, at least one second switch element connected to the failed battery cell is disconnected, so that the failed battery cell is disconnected from another adjacent battery cell; the first switch element corresponding to the failed battery cell is closed, so that the positive electrode and the negative electrode of the failed battery cell are short-circuited, and then the two adjacent battery cells of the failed battery cell are short-circuited; that is, the present application disconnects the failed battery cell through the second switch element when a failed battery cell is detected, and short-circuits the battery cells on both sides of the failed battery cell through the first switch element, which is conducive to reducing the influence of the failed battery cell on the battery pack and can realize the reuse of the battery pack. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A schematic diagram of the framework structure of an energy storage system provided in one embodiment of the present application;

[0022] Figure 2 A schematic diagram of the framework structure of an energy storage system provided in another embodiment of the present application;

[0023] Figure 3 A schematic diagram of the framework structure of an energy storage system provided in yet another embodiment of the present application;

[0024] Figure 4 A schematic diagram of the framework structure of an energy storage system provided in yet another embodiment of the present application;

[0025] Figure 5 A schematic diagram of the framework structure of an energy storage system provided in yet another embodiment of the present application;

[0026] Figure 6 A schematic diagram of the framework structure of an energy storage system provided in yet another embodiment of the present application.

[0027] Specific element symbol description: 100 - battery pack, 110 - battery cell, 120 - first switch element, 130 - second switch element, 140 - detection module, 200 - battery cluster, K1 - first circuit breaker, K2 - second circuit breaker. DETAILED DESCRIPTION

[0028] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0029] It should be noted that when an element is referred to as being "disposed on" another element, it can be directly on the other element or indirectly 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.

[0030] It should be understood that the terms "length", "width", "up", "down", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application.

[0031] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0032] It is important to know that due to global warming, countries are jointly responding to climate change, and the global energy structure is irreversibly transforming to a low-carbon one. With the intensive introduction of domestic energy storage policies and clear requirements for storage on the power generation side, energy storage systems have become popular. With the rapid development of new energy vehicles, energy storage systems and other fields, battery technology has been widely used. Then the one-time investment cost of using a new battery for energy storage and power generation is too high. However, as the battery is used for a longer time, some cells will gradually fail due to increased internal resistance, capacity attenuation and other reasons, resulting in a decrease in the performance of the entire battery pack, which cannot meet the original design requirements and thus faces retirement. With the vigorous development of the new energy industry, the number of battery updates and retirements is increasing. The use of second-life batteries has become a priority for energy storage systems.

[0033] In the process of handling retired batteries, traditional methods often have two major problems: one is high cost and possible damage to the battery. Due to the complex internal structure of the battery pack, if each battery cell needs to be inspected in detail and the failed battery cell needs to be replaced, it will not only require high costs, but also may damage other non-failed battery cells or the entire battery pack structure due to improper operation during the disassembly process. The second is waste of resources. If the entire battery pack is directly screened and eliminated as a whole, it may still contain a large number of batteries that are not completely failed. The remaining capacity and performance of these batteries still have certain utilization value. Direct elimination will cause serious waste of resources.

[0034] Specifically, if these retired batteries are disassembled, on the one hand, the batteries will be further damaged, which may cause leakage, short circuit or even scrapping. On the other hand, disassembling the batteries will waste labor and time. Diagnosing, evaluating, and grading these replacement or retired batteries is also a very complex and comprehensive system engineering with high difficulty.

[0035] Therefore, the present application improves the relevant energy storage system and energy storage method based on this.

[0036] See also Figure 1 , Figure 1 The schematic diagram of the framework structure of the energy storage system provided in this embodiment is shown. The energy storage system of this embodiment includes a battery pack 100, which includes a plurality of battery cells 110, a plurality of first switch components 120 and a plurality of second switch components 130; the plurality of battery cells 110 are sequentially arranged in series; the plurality of first switch components 120 correspond to the plurality of battery cells 110 one by one, and the first switch components 120 are connected in series between the positive and negative electrodes of the battery cells 110; the second switch components 130 are arranged in series between two adjacent battery cells 110, and the second switch components 130 are arranged in series between the first switch components 120 and the second switch components 130. Between the positive electrode or the negative electrode of the battery cell 110; the battery pack 100 is configured such that when at least one battery cell 110 among the multiple battery cells 110 is a failed battery cell 110, the first switch element 120 corresponding to the failed battery cell 110 is closed to short-circuit the positive electrode and the negative electrode of the failed battery cell 110, thereby short-circuiting the two adjacent battery cells 110 of the failed battery cell; and at least one second switch element 130 connected to the failed battery cell 110 is disconnected to disconnect the failed battery cell 110 from another adjacent battery cell 110.

[0037] It should be explained that a plurality of cells 110 are arranged in series to form an energy storage unit of the battery pack 100. A failed cell 110 is a cell 110 with too large internal resistance or too low capacity, and may also be called a short-board cell 110. Due to the "barrel effect", the performance of a failed cell 110 will greatly affect the performance of the entire battery pack 100.

[0038] When a failed cell 110 is generated in the current battery pack 100, either the entire battery pack 100 is discarded, or the battery pack 100 is disassembled for inspection and replacement, which results in a huge waste of cost and a low recycling rate of retired batteries. However, the present application, when a failed cell 110 is detected, only the positive and negative electrodes of the failed cell 110 are short-circuited through the first switch 120, thereby short-circuiting two adjacent cells 110 of the failed cell; and the failed cell 110 is disconnected through the second switch 130, which is conducive to reducing the impact of the failed cell 110 on the battery pack 100 and can achieve the reuse of the battery pack 100.

[0039] Specifically, in this embodiment, each battery cell 110 is equipped with a first switch 120, whose main function is to short-circuit the positive and negative electrodes of the battery cell 110 by closing when the battery cell 110 fails, thereby short-circuiting the two adjacent battery cells 110 of the failed battery cell. The main responsibility of the second switch 130 is to disconnect the connection with the failed battery cell 110 when a battery cell 110 fails, so as to isolate the failed battery cell 110 and prevent its failure from spreading to the entire battery pack 100. It can also reduce the time cost of re-evaluating the diagnosis and reduce the technical difficulty of capacity and resistance matching.

[0040] In some embodiments of this application, please continue to refer to Figure 1 In this embodiment, the failed battery cell 110 is arranged between two battery cells 110, and the failed battery cell 110 has two second switch elements 130 for connecting the two battery cells 110; wherein the battery pack 100 is configured to disconnect the two second switch elements 130 connecting the failed battery cell 110 when at least one battery cell 110 among the multiple battery cells 110 is a failed battery cell 110.

[0041] It should be explained that when all the battery cells 110 are working normally, all the second switch elements 130 are in a closed state, allowing the current to flow smoothly between the battery cells 110, thereby maintaining the normal operation of the battery pack 100. Once a battery cell 110 is determined to be a failed battery cell 110, the two second switch elements 130 connected to the failed battery cell 110 are disconnected. In this way, the failed battery cell 110 is completely isolated in the battery pack 100 and no longer participates in the transmission of current. In this way, the middle battery cell 110 can disconnect the second switch elements 130 on both sides to prevent the failed battery cell 110 from affecting the two adjacent battery cells 110.

[0042] Specifically, if there are failed cells 110 in the cascade battery pack 100, the first switch elements 120 on both sides of the failed cells 110 are disconnected, and the first switch element 120 is used to short-circuit the negative electrode of the previous cell 110 (an adjacent cell 110) of the failed cell 110 and the positive electrode of the next-level cell 110 (another adjacent cell 110). When there are failed cells 110 in the cascade battery pack 100, the failed cells 110 are disconnected, and the number of collection connection strings of the BMS (battery management system) in the cascade battery pack 100 corresponding to the failed cells 110 is modified and reduced to form a new cascade battery pack 100.

[0043] In some embodiments of this application, please refer to Figure 2 , Figure 2 The schematic diagram of the framework structure of the energy storage system provided in this embodiment is shown. The energy storage system of this embodiment also includes a detection module 140, which is used to perform battery cell leakage detection, chassis sealing detection or temperature detection on the energy storage system. The detection module 140 integrates battery cell 110 leakage detection, chassis sealing, temperature detection and fire protection, and can perform safety assessment and prevention in the later use of the cascade battery module. For example, the detection module 140 includes a leakage detection unit, a chassis sealing detection unit or a temperature detection unit.

[0044] In some embodiments of the present application, the second switch element 130 includes at least one of a copper bar, an aluminum bar, a power wire harness, or a nickel sheet. The second switch element 130 may also be made of other current-carrying materials.

[0045] In some embodiments of this application, please refer to Figure 3 , Figure 3 The schematic diagram of the framework structure of the energy storage system provided in this embodiment is shown. In this embodiment, there are multiple battery packs 100, and multiple battery packs 100 are connected in series to form a battery cluster 200, and the battery cluster 200 is connected to the DC bus; the energy storage system also includes a first circuit breaker K1 and a first control unit, the first circuit breaker K1 is arranged between the battery cluster 200 and the DC bus, and the first control unit is used to control the on / off of the first circuit breaker K1.

[0046] Specifically, after the failed battery cell 110 is removed from the echelon battery pack 100, a new echelon battery pack 100 is formed. After multiple echelon battery packs 100 are connected in series, their total positive and negative poles are connected to the first circuit breaker K1 to form an echelon battery cluster 200. Battery clusters 200 with different numbers of strings and voltage levels are respectively connected to the first control unit, and multiple groups of first control unit bus terminals are connected in parallel to the DC bus to form a new DC bus through DC coupling. The positive and negative poles of the DC bus are connected to the PCS end of the energy storage system, and users can connect the load to the AC side of the PCS for charging and discharging.

[0047] In some embodiments of this application, please refer to Figure 4 , Figure 4 The schematic diagram of the framework structure of the energy storage system provided in this embodiment is shown. The energy storage system also includes multiple first coupling control units, the number of battery clusters 200 is multiple, the multiple first coupling units correspond to the multiple battery clusters 200 one by one, and the multiple battery clusters 200 are connected in parallel to the DC bus through the multiple first coupling units. It can be realized that battery clusters 200 with different numbers of strings, different voltage standards, different capacities and different battery types form an energy storage system.

[0048] It is understandable that the energy storage system forms a battery cluster 200 by connecting multiple battery packs 100 in series, and the battery cluster 200 is then connected to the power grid or other loads through a DC bus. A first circuit breaker K1 is set between the battery cluster 200 and the DC bus, and its on / off state is controlled by a first control unit to achieve safe and controllable transmission of electric energy. Such a system structure not only ensures the efficient operation of the energy storage system, but also takes into account safety and reliability.

[0049] In some embodiments of this application, please refer to Figure 5 , Figure 5 The schematic diagram of the framework structure of the energy storage system provided in this embodiment is shown. In this embodiment, there are multiple battery packs 100, and multiple battery packs 100 are connected in series to form a battery cluster 200, and the battery cluster 200 is connected to the AC bus; the energy storage system also includes a second circuit breaker K2 and a second control unit, the second circuit breaker K2 is arranged between the battery cluster 200 and the AC bus, and the second control unit is used to control the on / off of the second circuit breaker K2.

[0050] Specifically, after the failed battery cell 110 is removed from the secondary battery pack 100, a new secondary battery pack 100 is formed. After multiple secondary battery packs 100 are connected in series, their total positive and total negative electrodes are connected to the second circuit breaker K2 to form a secondary battery cluster 200. Battery clusters 200 with different numbers of strings and voltage levels are respectively connected to the second control unit, and the AC sides of multiple groups of second control units are connected in parallel to the AC bus to form a new AC bus through AC coupling. Users can connect loads to the AC bus for charging and discharging.

[0051] In some embodiments of this application, please refer to Figure 6 , Figure 6 The schematic diagram of the framework structure of the energy storage system provided by this embodiment is shown. The energy storage system of this embodiment also includes multiple second coupling control units, the number of battery clusters 200 is multiple, the multiple second coupling units correspond to the multiple battery clusters 200 one by one, and the multiple battery clusters 200 are connected in parallel to the AC bus through the multiple second coupling units. It can be realized that battery clusters 200 with different numbers of strings, different voltage standards, different capacities and different battery types form an energy storage system.

[0052] It is understandable that the energy storage system is provided with a second circuit breaker K2 between the battery cluster 200 and the AC bus, and the second control unit performs on / off control. This design improves the safety and flexibility of the system, allowing the energy storage system to better adapt to the needs of different application scenarios and achieve efficient operation. At the same time, through intelligent management and scheduling strategies, the system can achieve efficient use of electric energy and long-term stable operation of the energy storage system.

[0053] Furthermore, in order to better implement the energy storage system in any of the above embodiments, based on the above energy storage system, the present application also provides an energy storage method, which is applied to the above energy storage system.

[0054] In some embodiments of the present application, the energy storage system includes a control module and a battery cluster 200 . The control module is used to detect the battery cluster 200 and control the charging and discharging parameters of the battery cluster 200 according to the detection data.

[0055] In some embodiments, the detection data can be status information of the battery cluster 200, PCS (power conversion system), fire protection and other equipment; the charging and discharging parameters can be charging parameters, discharging parameters, power parameters, voltage parameters, and current parameters; the control module can estimate the SOC (remaining power) and SOH (health status) of the energy storage system. In this way, it is conducive to effective feedback of the first state of the cascade energy storage system and providing the optimal charging and discharging scheduling strategy. In the energy storage system of this embodiment, battery clusters 200 with different numbers of strings, different voltage standards, different capacities and different battery types can be connected, and charging and discharging scheduling and management are performed through the control module.

[0056] In the energy storage system of this embodiment, if the battery cluster 200 needs maintenance, repair, or replacement, the entire system does not need to be completely disconnected. The battery cluster 200 can be replaced separately by remotely controlling it through the control module or by disconnecting the circuit breaker of the battery cluster 200 through the local port, thereby realizing online replacement and upgrading of the energy storage system.

[0057] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0058] The basic concepts have been described above. Obviously, for those skilled in the art, the above detailed disclosure is only for example and does not constitute a limitation of the present application. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements and amendments to the present application. Such modifications, improvements and amendments are suggested in the present application, so such modifications, improvements and amendments still belong to the spirit and scope of the exemplary embodiments of the present application.

[0059] At the same time, the present application uses specific words to describe the embodiments of the present application. For example, "one embodiment", "an embodiment", and / or "some embodiments" refer to a certain feature, structure or characteristic related to at least one embodiment of the present application. Therefore, it should be emphasized and noted that "one embodiment" or "an embodiment" or "an alternative embodiment" mentioned twice or more in different positions in this specification does not necessarily refer to the same embodiment. In addition, some features, structures or characteristics in one or more embodiments of the present application can be appropriately combined.

[0060] Similarly, it should be noted that in order to simplify the description of the disclosure of this application and thus help understand one or more embodiments of the invention, in the above description of the embodiments of this application, multiple features are sometimes combined into one embodiment, figure or description thereof. However, this disclosure method does not mean that the features required by the object of this application are more than the features mentioned in the claims. In fact, the features of the embodiments are less than all the features of the single embodiment disclosed above.

[0061] The embodiments described above are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. An energy storage system, characterized in that: The energy storage system includes a battery pack, and the battery pack includes: A plurality of battery cells, wherein the plurality of battery cells are sequentially arranged in series; A plurality of first switch elements, corresponding one to one with the plurality of battery cells, and the first switch elements are connected in series between the positive electrode and the negative electrode of the battery cell; A plurality of second switch elements, wherein the second switch elements are arranged in series between two adjacent battery cells, and the second switch elements are arranged between the first switch element and the positive electrode or the negative electrode of the battery cell; The battery pack is configured such that when at least one battery cell among the multiple battery cells is a failed battery cell, at least one of the second switch components connected to the failed battery cell is disconnected to disconnect the failed battery cell from another adjacent battery cell; and the first switch component corresponding to the failed battery cell is closed to short-circuit the positive and negative electrodes of the failed battery cell, thereby short-circuiting the two adjacent battery cells of the failed battery cell.

2. The energy storage system according to claim 1, characterized in that: The failed battery cell is arranged between two of the battery cells, and the failed battery cell has two second switch elements for connecting the two battery cells; wherein the battery pack is configured so that when at least one of the plurality of battery cells is a failed battery cell, the two second switch elements connecting the failed battery cells are disconnected.

3. The energy storage system according to claim 1, characterized in that: The energy storage system further comprises a detection module, and the detection module is used to perform battery cell leakage detection, chassis sealing detection or temperature detection on the energy storage system.

4. The energy storage system according to claim 1 or 2, characterized in that: The second switch element includes at least one of a copper busbar, an aluminum busbar, a power wiring harness, or a nickel sheet.

5. The energy storage system according to claim 1, characterized in that: There are multiple battery packs, which are connected in series to form a battery cluster, and the battery cluster is connected to a DC bus. The energy storage system also includes a first circuit breaker and a first control unit, the first circuit breaker is arranged between the battery cluster and the DC bus, and the first control unit is used to control the on / off of the first circuit breaker.

6. The energy storage system according to claim 5, characterized in that: The energy storage system further includes a plurality of first coupling control units. There are a plurality of battery clusters. The plurality of first coupling units correspond one to one with the plurality of battery clusters. The plurality of battery clusters are connected in parallel to the DC bus through the plurality of first coupling units.

7. The energy storage system according to claim 1, characterized in that: There are multiple battery packs, which are connected in series to form a battery cluster, and the battery cluster is connected to the AC bus; the energy storage system also includes a second circuit breaker and a second control unit, the second circuit breaker is arranged between the battery cluster and the AC bus, and the second control unit is used to control the on / off of the second circuit breaker.

8. The energy storage system according to claim 7, characterized in that: The energy storage system further includes a plurality of second coupling control units. There are a plurality of battery clusters. The plurality of second coupling units correspond one to one with the plurality of battery clusters. The plurality of battery clusters are connected in parallel to the AC bus through the plurality of second coupling units.

9. An energy storage method, characterized in that: The energy storage method is applied to the energy storage system according to any one of claims 1 to 8.

10. The energy storage method according to claim 9, characterized in that: The energy storage system comprises a control module and a battery cluster. The control module is used to detect the battery cluster and control the charging and discharging parameters of the battery cluster according to the detection data.

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