Method and apparatus for controlling high-voltage energy storage system to enter maintenance state

Abstract

The present application relates to the technical field of high-voltage energy storage, and relates to a method and apparatus for controlling a high-voltage energy storage system to enter a maintenance state, a computer device and a storage medium. A high-voltage energy storage system comprises at least one energy storage branch, and the energy storage branch comprises a plurality of cascaded energy storage sub-modules. The method in one embodiment comprises: controlling an energy storage branch to be maintained to be in a non-power output state; controlling the branch voltage of said energy storage branch to be less than a branch voltage safety value; and controlling the current of an energy storage sub-module to be maintained in said energy storage branch to be less than a current safety value, and grounding a housing of said energy storage sub-module.

Description

Method and device for controlling high-voltage energy storage system to enter maintenance state Cross-references

[0001] This application refers to Chinese patent application No. 2024101772262, filed on February 8, 2024, entitled “Method and device for controlling a high-voltage energy storage system to enter a maintenance state”, which is incorporated into this application in its entirety by reference. Technical Field

[0002] The present application relates to the field of high-voltage energy storage technology, and in particular to a method, apparatus, computer equipment, storage medium, and computer program product for controlling a high-voltage energy storage system to enter a maintenance state. Background Art

[0003] At present, as a new type of energy storage system, the research and implementation of high-voltage energy storage systems are in the initial stage, and few actual projects have been launched. Therefore, the development of maintenance methods for them is also blank. For high-voltage energy storage systems, they adopt a cascade structure of energy storage submodules. The voltage to ground of devices in different parts of the system is different. The submodule with the highest voltage to ground can reach tens of kilovolts or even hundreds of kilovolts (AC or DC). Because in high-voltage energy storage systems, the voltage of system submodules and battery pack shells generally uses some kind of clamping method to make the shell voltage of each submodule at a high voltage to the ground, maintenance personnel cannot directly enter for maintenance. Therefore, it is urgent to provide a means to make the high-voltage energy storage system maintainable based on the characteristics of the high-voltage energy storage system, so that the high-voltage energy storage system can be put into a state where personnel can conduct on-site maintenance, and solve the problem that its design is difficult to inspect. Summary of the Invention

[0004] Based on this, it is necessary to provide a method, device, computer equipment, storage medium and computer program product for controlling a high-voltage energy storage system to enter a maintenance state, which can control a high-voltage energy storage battery to enter a maintenance state, in order to address the above technical problems.

[0005] In a first aspect, the present application provides a method for controlling a high-voltage energy storage system to enter a maintenance state, wherein the high-voltage energy storage system includes at least one energy storage branch, and the energy storage branch includes a plurality of cascaded energy storage sub-modules; the method includes: controlling the energy storage branch to be maintained to be in a no-power output state; controlling the branch voltage of the energy storage branch to be maintained to be less than a branch voltage safety value; controlling the current of the energy storage sub-module to be maintained in the energy storage branch to be maintained to be less than a current safety value; and grounding the shell of the energy storage sub-module to be maintained.

[0006] Based on the method for controlling a high-voltage energy storage system to enter a maintenance state in the embodiment of the present application as described above, when it is necessary to control the high-voltage energy storage system to enter a maintenance state, the method controls the energy storage branch to be repaired to be in a no-power output state, so that the energy storage branch to be repaired has no power output, and controls the branch voltage of the energy storage branch to be repaired to be less than the branch voltage safety value, so that the energy storage branch to be repaired is in a maintenance preparation state, and controls the current of the energy storage submodule to be repaired in the energy storage branch to be repaired to be less than the current safety value, so that the current caused by the battery in the energy storage submodule to be repaired can be less than the current safety value, thereby improving the maintenance safety, and reducing the energy storage submodule to be repaired. The shell is grounded, so that the shell voltage of the energy storage submodule to be repaired is reduced to the ground potential, so as to further improve the maintenance safety. After the above operation, the energy storage branch to be repaired can be put into a no-power output state, the branch voltage of the energy storage branch to be repaired is within the range of the branch voltage safety value, the current in the energy storage submodule to be repaired is within the range of the current safety value, and the shell voltage of the energy storage submodule to be repaired is reduced to the ground potential, thereby reducing the safety problems caused by the energy storage branch to be repaired and the energy storage submodule to be repaired in the energy storage branch being in a high-voltage state, so that the high-voltage energy storage system can enter a state where maintenance personnel can perform on-site maintenance, thereby improving the safety of maintenance.

[0007] In some embodiments, controlling the energy storage branch to be repaired to be in a no-power output state includes: controlling the branch current of the energy storage branch to be repaired to be zero.

[0008] Based on the solution of this embodiment, by controlling the branch current of the energy storage branch to be repaired to 0, the branch current of the energy storage branch to be repaired can be made 0, that is, there is no current output as a whole, and thus it is in a no-power output state, which can make the energy storage branch to be repaired in a maintenance preparation state to improve safety.

[0009] In some embodiments, controlling the energy storage branch to be repaired to be in a no-power output state includes: controlling the energy storage branch to be repaired to be in a locked state so that the branch current of the energy storage branch to be repaired is less than a preset value.

[0010] Based on the solution of this embodiment, by controlling the energy storage branch to be repaired to be in a locked state, when the energy storage branch to be controlled is in a locked state, theoretically no branch current flows through the energy storage branch to be repaired, that is, there is no current output as a whole, the branch current is less than a preset value, and it is in a no-power output state. The control method is simple and convenient, and the operability is strong.

[0011] In some embodiments, controlling the energy storage branch to be repaired to be in a locked state includes: sending a locking instruction to the branch controller of the energy storage branch to be repaired, wherein the locking instruction is used to control the energy storage branch to be repaired to stop switching, so that the energy storage branch to be repaired is in a locked state.

[0012] Therefore, when the energy storage branch to be repaired is controlled to be in a locked state, it can be achieved by sending a locking instruction to the branch controller of the energy storage branch to be repaired. The energy storage branch to be repaired can stop switching based on the locking instruction, so that the energy storage branch to be repaired is in a locked state. At this time, the branch current of the energy storage branch to be repaired is less than the preset value, that is, there is no current output as a whole, and it is in a no-power output state. The control method is simple and convenient, and the operability is strong.

[0013] In some embodiments, a locking instruction is sent to a branch controller of an energy storage branch to be overhauled, and the locking instruction is used to control the energy storage branch to be overhauled to stop switching so that the energy storage branch to be overhauled is in a locked state, including: sending a locking instruction to a sub-module controller of an energy storage sub-module of the energy storage branch to be overhauled, and the locking instruction is used to instruct the sub-module controller to turn off the IGBT of the power module in the energy storage sub-module, and the branch controller includes a sub-module controller.

[0014] Therefore, when a locking instruction is sent to the branch controller of the energy storage branch to be repaired to control the energy storage branch to be repaired to stop switching, the submodule controller can be instructed to turn off the IGBT of the power module in the energy storage submodule, that is, by turning off the IGBT of the power module in the energy storage submodule, the energy storage submodule of the energy storage branch to be repaired can be stopped from switching, so that the branch current of the energy storage branch to be repaired is 0. The control method is simple and convenient, and the operability is strong.

[0015] In some embodiments, after controlling the energy storage branch to be repaired to be in a no-power output state and before controlling the voltage of the energy storage branch to be repaired to be less than the branch voltage safety value, it also includes: controlling the energy storage branch to be repaired to be in an isolated and tripped state.

[0016] Based on this embodiment, after controlling the energy storage branch to be repaired to be in a no-power output state, the energy storage branch to be repaired is further controlled to be in an isolated and disconnected state, thereby isolating and disconnecting the current of the energy storage branch to be repaired, thereby further improving the safety of the repair state.

[0017] In some embodiments, controlling the energy storage branch to be repaired to be in an isolated and tripped state includes: controlling the isolating switch of the energy storage branch to be repaired to be in an tripped state.

[0018] Since the isolating switch of the energy storage branch can provide a visible break in the air but cannot interrupt the current, when the energy storage branch to be repaired is controlled to be in an isolated and disconnected state, by controlling the isolating switch of the energy storage branch to be repaired to be in an open state, the possibility of current passing through the energy storage valve can be reduced, thereby further improving the safety of maintenance.

[0019] In some embodiments, after controlling the isolating switch of the energy storage branch to be repaired to be in an open state, the method further includes: detecting the isolating switch state of the isolating switch of the energy storage branch to be repaired, and determining whether the isolating switch is correctly opened according to the isolating switch state.

[0020] Therefore, after performing the work of opening the isolating switch of the energy storage branch to be repaired, the isolating switch status of the isolating switch of the energy storage branch to be repaired is further detected to determine whether the isolating switch of the energy storage branch to be repaired has been correctly opened, so as to further improve the maintenance safety.

[0021] In some embodiments, after controlling the energy storage branch to be repaired to be in a no-power output state and before controlling the branch voltage of the energy storage branch to be repaired to be less than the branch voltage safety value, it also includes: controlling the energy storage branch to be repaired to be in a disconnected state.

[0022] Thus, after controlling the energy storage branch to be repaired to be in a no-power output state, the energy storage branch to be repaired is further disconnected, so that the energy storage circuit to be repaired is in a disconnected state, reducing the possibility of current existing due to the energy storage circuit to be repaired not being disconnected, and further improving the repair safety.

[0023] In some embodiments, controlling the energy storage branch to be repaired to be in a disconnected state includes: controlling a circuit breaker of the energy storage branch to be repaired to be in an open state.

[0024] Therefore, when a circuit breaker is provided for the energy storage branch to be repaired, the current of the energy storage branch to be repaired can be disconnected by controlling the circuit breaker of the energy storage branch to be repaired to be in the open state, thereby further improving the safety of the repair state.

[0025] In some embodiments, after controlling the circuit breaker of the energy storage branch to be repaired to be in an open state, the method further includes: detecting the circuit breaker state of the circuit breaker of the energy storage branch to be repaired, and determining whether the circuit breaker is correctly opened according to the circuit breaker state.

[0026] Therefore, after executing the work of controlling the circuit breaker of the energy storage branch to be repaired to be in the open state, the circuit breaker state of the circuit breaker of the energy storage branch to be repaired is further detected to determine whether the circuit breaker of the energy storage branch to be repaired has been correctly opened, so as to further improve the safety of maintenance.

[0027] In some embodiments, controlling the energy storage branch to be repaired to be in a disconnected state includes: controlling a fast switch of the energy storage branch to be repaired to be in an open state.

[0028] In a high-voltage energy storage system, a fast switch can quickly cut off the fault current when a fault occurs, and has a fast opening and closing speed. Therefore, when it is necessary to control the energy storage branch to be repaired in a disconnected state, by controlling the fast switch of the energy storage branch to be repaired in an open state, it can not only meet the need to disconnect the energy storage branch to be repaired, improve the safety of the maintenance state, but also help improve maintenance efficiency.

[0029] In some embodiments, after controlling the fast switch of the energy storage branch to be repaired to be in the open state, the method further includes: detecting the fast switch state of the fast switch of the energy storage branch to be repaired, and determining whether the fast switch is correctly opened according to the fast switch state.

[0030] Therefore, after executing the work of controlling the fast switch of the energy storage branch to be repaired to be in the open state, the fast switch state of the fast switch of the energy storage branch to be repaired is further detected to determine whether the fast switch of the energy storage branch to be repaired has been correctly opened, so as to further improve the safety of maintenance.

[0031] In some embodiments, controlling the voltage of the energy storage branch to be repaired to be lower than the branch voltage safety value includes: performing voltage reduction processing through a step-down module of the energy storage branch to be repaired so that the voltage of the energy storage branch to be repaired is lower than the branch voltage safety value.

[0032] Based on this embodiment, a step-down module can be configured for the energy storage branch. During the normal operation of the energy storage branch, the step-down module is not enabled. When it is necessary to enter the maintenance state for maintenance and it is necessary to control the voltage of the energy storage branch to be repaired to be lower than the branch voltage safety value, the step-down module is enabled to perform voltage reduction processing through the step-down module so that the voltage of the energy storage branch to be repaired is lower than the branch voltage safety value, thereby improving maintenance safety.

[0033] In some embodiments, controlling the voltage of the energy storage branch to be repaired to be less than a branch voltage safety value includes: controlling the energy storage branch to be repaired to be grounded.

[0034] Based on this embodiment, since most high-voltage energy storage systems are series systems, when not grounded, the system voltage and the shell voltage of each submodule are still in a suspended state. Therefore, when it is necessary to control the voltage of the energy storage branch to be repaired to be lower than the branch voltage safety value, by controlling the grounding switch of the energy storage branch to be repaired to be closed, one or both ends of the grounding switch of the energy storage branch to be repaired can be at the ground potential, which can further improve safety and the control method is simple and convenient.

[0035] In some embodiments, controlling the energy storage branch to be repaired to be grounded includes: controlling the grounding switch of the energy storage branch to be repaired to be closed.

[0036] Based on this embodiment, when it is necessary to control the grounding of the energy storage branch to be repaired, by controlling the closing of the grounding switch of the energy storage branch to be repaired, one or both ends of the grounding switch of the energy storage branch to be repaired can be at the ground potential, which can further improve safety. The control method is simple and convenient, and no additional devices are required.

[0037] In some embodiments, after controlling the energy storage branch to be repaired to be grounded, the method further includes: detecting a grounding switch state of a grounding switch of the energy storage branch to be repaired, and determining whether the grounding switch is correctly closed according to the grounding switch state.

[0038] Therefore, after executing the work of controlling the closing of the grounding switch of the energy storage branch to be repaired, the grounding switch status of the grounding switch of the energy storage branch to be repaired is further detected to confirm whether the grounding switch of the energy storage branch to be repaired has been correctly closed, so as to further improve the safety of maintenance.

[0039] In some embodiments, the energy storage submodule includes an energy storage battery and a power module, and controlling the current of the energy storage submodule to be repaired in the energy storage branch to be repaired to be less than the current safety value includes: controlling the discharge of the capacitor in the power module of the energy storage submodule to be repaired so that the current of the energy storage submodule to be repaired in the energy storage branch to be repaired is less than the current safety value.

[0040] Since in the high-voltage energy storage system, the energy storage submodule is large in size and the capacitors in the power module of the energy storage submodule are in a high-voltage state, it is easy for current to flow in the energy storage submodule. Therefore, by controlling the discharge of the capacitors in the power module of the energy storage submodule to be repaired, the voltage of the capacitors in the power module can be reduced, so that the current of the energy storage submodule to be repaired in the energy storage branch to be repaired is less than the current safety value, allowing maintenance personnel to enter the energy storage submodule to be repaired for maintenance, thereby further improving maintenance safety.

[0041] In some embodiments, the power module includes capacitors and resistors; controlling the discharge of the capacitors in the power module of the energy storage submodule to be repaired includes: disconnecting the connection between the energy storage battery of the energy storage submodule to be repaired and the power module to allow the capacitors in the power module to discharge to the resistors of the power module.

[0042] In high-voltage energy storage systems, some energy storage submodules are provided with capacitors and resistors. Therefore, by disconnecting the connection between the energy storage battery of the energy storage submodule to be repaired and the power module, the capacitor and the resistor in the power module form a loop. Based on the formed loop, the capacitor of the power module will discharge the resistor of the power module, thereby reducing the voltage of the capacitor in the power module. On this basis, the current of the energy storage submodule to be repaired in the energy storage branch to be repaired can be made less than the current safety value, allowing maintenance personnel to enter the energy storage submodule to be repaired for maintenance, thereby further improving maintenance safety.

[0043] In some embodiments, disconnecting the energy storage battery of the energy storage submodule to be repaired and the power module includes: disconnecting an isolation switch between the parallel energy storage battery of the energy storage submodule to be repaired and the power module.

[0044] Since there are usually multiple energy storage batteries in the energy storage submodule, and these multiple energy storage batteries are connected to the power module in parallel, when it is necessary to disconnect the energy storage battery of the energy storage submodule to be repaired and the power module, the parallel energy storage batteries of the energy storage submodule to be repaired and the power module can be directly disconnected by disconnecting the isolation switch between the parallel energy storage batteries of the energy storage submodule to be repaired and the power module. This can put the parallel energy storage batteries of the energy storage submodule to be repaired and the power module into a disconnected state, so that the power module is not connected to the parallel energy storage batteries, so that the capacitor and the resistor in the power module form a loop. Based on the formed loop, the capacitor of the power module will discharge the resistor of the power module, so that the voltage of the capacitor in the power module is reduced. On this basis, the current of the energy storage submodule to be repaired in the energy storage branch to be repaired can be made less than the current safety value. By disconnecting the isolation switch, a visible breakpoint can be provided, which can improve reliability.

[0045] In some embodiments, disconnecting the energy storage battery of the energy storage submodule to be repaired and the power module includes: disconnecting a branch switch of the parallel energy storage battery.

[0046] Since there are usually multiple energy storage batteries in the energy storage submodule, and these multiple energy storage batteries are connected to the power module in parallel, when it is necessary to disconnect the connection between the energy storage battery of the energy storage submodule to be repaired and the power module, the branch switch of the parallel energy storage battery can be directly disconnected to put the energy storage switch of the parallel energy storage battery into an off state, so that there is no current on the busbar of the energy storage battery, so that the capacitor and the resistor in the power module form a loop. Based on the formed loop, the capacitor of the power module will discharge the resistor of the power module, so that the voltage of the capacitor in the power module is reduced. On this basis, the current of the energy storage submodule to be repaired in the energy storage branch to be repaired can be made less than the current safety value.

[0047] In some embodiments, disconnecting the energy storage battery of the energy storage submodule to be repaired and the power module includes: disconnecting an isolation switch between the parallel energy storage battery and the power module and a branch switch of the parallel energy storage battery.

[0048] Since there are usually multiple energy storage batteries in the energy storage submodule, and these multiple energy storage batteries are connected to the power module in parallel, when it is necessary to disconnect the energy storage battery of the energy storage submodule to be repaired and the power module, both the isolating switch between the parallel energy storage batteries of the energy storage submodule to be repaired and the power module is disconnected, and the branch switch of the parallel energy storage batteries is disconnected. Disconnecting the isolating switch not only provides a visible breakpoint, thereby improving reliability, but also ensures that there is no current on the busbar of the energy storage battery. Through the dual control method, the capacitor and the resistor in the power module form a loop. Based on the formed loop, the capacitor of the power module discharges the resistor of the power module, thereby improving the reliability of disconnecting the energy storage battery of the energy storage submodule to be repaired and the power module, and increasing the possibility of ensuring that the current of the energy storage submodule to be repaired in the energy storage branch to be repaired is less than the current safety value.

[0049] In some embodiments, the energy storage submodule also includes a discharge module, and the power module is selectively connected to the energy storage battery and the discharge module; controlling the discharge of the capacitor in the power module of the energy storage submodule to be repaired includes: controlling the power module to switch to connection with the discharge module so that the capacitor in the power module is discharged through the discharge module.

[0050] Therefore, a special discharge module is set in the energy storage submodule, and the power module is connected to the energy storage battery and the discharge module in a selective manner. During the normal operation of the energy storage submodule, the power module is connected to the energy storage module. When it is necessary to enter the maintenance state for maintenance, the power module is disconnected from the energy storage module and switched to the discharge module. The capacitor of the power module will be discharged through the discharge module, thereby reducing the voltage of the capacitor in the power module, making the current of the energy storage submodule to be repaired in the energy storage branch to be repaired less than the current safety value, so that maintenance personnel can enter the energy storage submodule to be repaired for maintenance, so as to further improve maintenance safety.

[0051] In some embodiments, after disconnecting the isolating switch between the parallel energy storage battery and the power module, the method further includes: detecting the isolating switch status of the isolating switch of the energy storage submodule to be repaired, and determining whether the isolating switch is correctly opened according to the isolating switch status.

[0052] Therefore, after disconnecting the isolating switch between the parallel energy storage battery and the power module, the switching state of the isolating switch of the energy storage submodule to be repaired is further detected to determine whether the isolating switch of the energy storage submodule to be repaired has been correctly opened, thereby further improving the maintenance safety.

[0053] In some embodiments, grounding the shell of the energy storage submodule to be repaired includes any one of the following: hanging the shell of the energy storage submodule to be repaired on a grounding rod; connecting the shell of the energy storage submodule to be repaired to a ground wire; closing the standby grounding switch of the energy storage submodule to be repaired.

[0054] Therefore, when it is necessary to ground the shell of the energy storage submodule to be repaired, the shell of the energy storage submodule to be repaired can be grounded by hanging the shell of the energy storage submodule to be repaired on a grounding rod, connecting the shell of the energy storage submodule to be repaired to a ground wire, closing the standby grounding switch of the energy storage submodule to be repaired, etc., so that when actually performing the shell grounding operation, it can be selected according to the needs of the scene, which has strong flexibility and operability.

[0055] On the second aspect, the present application also provides a device for controlling a high-voltage energy storage system to enter a maintenance state, wherein the high-voltage energy storage system includes at least one energy storage branch, and the energy storage branch includes multiple cascaded energy storage sub-modules; the device includes a branch control module and a sub-module control module: a branch control module, used to control the energy storage branch to be repaired to be in a no-power output state, and control the voltage of the energy storage branch to be repaired to be less than the branch voltage safety value; a sub-module control module, used to control the current safety value of the energy storage sub-module to be repaired in the energy storage branch to be repaired, and ground the shell of the energy storage sub-module to be repaired.

[0056] In a third aspect, the present application further provides a computer device comprising a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps of the method of any of the above embodiments when executing the computer program.

[0057] In a fourth aspect, the present application further provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the method of any of the above embodiments.

[0058] In a fifth aspect, the present application further provides a computer program product, which includes a computer program that implements the steps of the method of any of the above embodiments when executed by a processor.

[0059] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, some specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiments below. The accompanying drawings are for illustration purposes only and are not to be construed as limiting the present application. Furthermore, identical reference numerals are used throughout the accompanying drawings to denote identical components. In the accompanying drawings: FIG1 is a schematic diagram of the architecture of a high-voltage energy storage system in one embodiment; FIG2 is a schematic diagram of the architecture of a high-voltage energy storage system in another embodiment; FIG3 is a schematic diagram of the architecture of a high-voltage energy storage system in another embodiment; FIG4 is a flow chart of a method for controlling a high-voltage energy storage system to enter a maintenance state in one embodiment; FIG5 is a schematic diagram of the structure of an energy storage submodule in one embodiment; FIG6 is a flow chart of a method for controlling a high-voltage energy storage system to enter a maintenance state in another embodiment; FIG7 is a flow chart of a method for controlling a high-voltage energy storage system to enter a maintenance state in another embodiment; FIG8 is a flow chart of a method for controlling a high-voltage energy storage system to enter a maintenance state in another embodiment; FIG9 is a flow chart of a method for controlling a high-voltage energy storage system to enter a maintenance state in a specific example; FIG10 is a block diagram of a device for controlling a high-voltage energy storage system to enter a maintenance state in one embodiment; FIG11 is a diagram of the internal structure of a computer device in one embodiment.

[0061] Reference numerals: 100 , energy storage branch; 500 , energy storage submodule; 501 , energy storage battery; 502 , power module; 503 , switch; 101 , branch control module; 102 , submodule control module. DETAILED DESCRIPTION

[0062] In order to make the purpose, technical solutions and advantages of this application more clear, the following further describes this application in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0063] The following embodiments of the technical solution of the present application will be described in detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application and are therefore only examples and are not intended to limit the scope of protection of the present application.

[0064] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned figure descriptions are intended to cover non-exclusive inclusions.

[0065] In the description of the embodiments of this application, the technical terms "first" and "second" are used only to distinguish different objects and should not be understood to indicate or imply relative importance or implicitly specify the quantity, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, the meaning of "plurality" is more than two, unless otherwise clearly and specifically defined.

[0066] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0067] In the description of the embodiments of this application, the term "and / or" is simply a description of the association relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can represent the following three situations: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this document generally indicates that the associated objects are in an "or" relationship.

[0068] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0069] In the description of the embodiments of this application, unless otherwise specified or limited, technical terms such as "connection" should be understood in a broad sense. For example, it can refer to a mechanical connection or an electrical connection; it can refer to a direct connection or an indirect connection through an intermediate medium; it can refer to internal communication between two components or an interaction between two components. For those skilled in the art, the specific meanings of the above terms in the embodiments of this application can be understood based on the specific circumstances.

[0070] At present, as a new type of energy storage system, the research and implementation of high-voltage energy storage systems are in the initial stage, with few actual projects on the market. Therefore, the development of maintenance methods for them is also blank. The maintenance methods used in fields such as flexible direct current cannot be applied to high-voltage energy storage systems. This is because, for high-voltage energy storage systems, they use a cascade structure of energy storage submodules. The voltage to ground of devices in different parts of the system is different. The submodule with the highest voltage to ground can reach tens of kilovolts or even hundreds of kilovolts (AC or DC). Because in high-voltage energy storage systems, the voltage of system submodules and battery pack shells is generally clamped in some way, so that the shell voltage of each submodule is at a high voltage to ground, maintenance personnel cannot directly enter for maintenance.

[0071] Based on this, it is necessary to provide a means to make the high-voltage energy storage system repairable according to the characteristics of the high-voltage energy storage system, so that the high-voltage energy storage system can be put into a state where personnel can conduct on-board maintenance.

[0072] Accordingly, an embodiment of the present application provides a method for controlling a high-voltage energy storage system to enter a maintenance state, which can be applied to a high-voltage energy storage system. Among them, some structural examples of the high-voltage energy storage system can be shown in Figures 1 to 3. In combination with Figures 1 to 3, the high-voltage energy storage system includes at least one energy storage branch, such as the energy storage branch 100 shown in Figure 1. Each energy storage branch includes a plurality of cascaded energy storage sub-modules (Sub-Module, SM). Each energy storage sub-module includes at least one energy storage battery and a power device for controlling the charging and discharging of the energy storage battery. For example, each power device can be a half-bridge or full-bridge power module composed of fully controlled devices such as IGBTs (Insulated Gate Bipolar Transistors). Multiple energy storage sub-modules are cascaded through power devices. In one embodiment, the cascade is achieved by connecting the input terminals of multiple power devices end to end in series, such as the energy storage sub-modules SM#1, SM#2, SM#3, SM#n-1, and SM#n shown in Figures 1 to 3. It should be understood that, in Figures 1 to 3, only some of the components related to the present application are shown. In actual technical application scenarios, the high-voltage energy storage system may include other components. Specifically, Figure 1 is a topological diagram of a high-voltage AC direct-hanging energy storage system (also called a high-voltage direct-hanging or high-voltage cascade energy storage system) of modular multilevel technology (Modular Multilevel Converter, MMC), and the energy storage system is connected to the AC bus; Figure 2 is a topological diagram of a high-voltage DC direct-hanging energy storage system, and the main difference between the topology of the high-voltage AC direct-hanging energy storage system and the high-voltage AC direct-hanging energy storage system shown in Figure 1 is that in the high-voltage DC direct-hanging energy storage system shown in Figure 2, the energy storage branch is directly hung on the DC bus; Figure 3 is a schematic diagram of an embodiment of another high-voltage AC direct-hanging energy storage system, also known as a star-shaped high-voltage direct-hanging energy storage system.

[0073] Accordingly, as shown in FIG4 , the method for controlling a high-voltage energy storage system to enter a maintenance state according to an embodiment of the present application includes the following steps.

[0074] Step S402: Control the energy storage branch to be repaired to be in a no-power output state.

[0075] The energy storage branch to be repaired refers to the energy storage branch that needs to be repaired. A high-voltage energy storage system generally includes multiple energy storage branches. When maintenance is required, one energy storage branch of the high-voltage energy storage system can be the energy storage branch to be repaired, or two or more energy storage branches of the high-voltage energy storage system can be the energy storage branches to be repaired. In some cases, all energy storage branches of the high-voltage energy storage system can also be the energy storage branches to be repaired.

[0076] The no-power output state refers to a state in which no power is theoretically output, i.e., no power is output to the outside. The energy storage branch to be repaired is in a no-power output state, i.e., the energy storage branch to be repaired does not output power to the outside.

[0077] By controlling the energy storage branch to be repaired to be in a no-power output state, the energy storage branch to be repaired can be prevented from outputting power to the outside, reducing the load of each component so that the system can be stopped smoothly, reducing the impact on the energy storage system, and reducing the safety impact on maintenance personnel caused by the energy storage branch in the power output state, which helps to improve maintenance safety.

[0078] Step S404: controlling the branch voltage of the energy storage branch to be repaired to be less than the branch voltage safety value.

[0079] The branch voltage safety value refers to the voltage value of the energy storage branch when maintenance personnel are able to enter the energy storage branch environment. In other words, when the branch voltage of the energy storage branch is at the branch voltage safety value, personnel entering the energy storage branch environment will not pose a safety threat to maintenance personnel. While there may be some impact on the maintenance personnel's safety, the impact is minimal and within the acceptable safety impact range.

[0080] Since the voltage of the energy storage branch is relatively high, voltage may still exist in the energy storage branch even when the energy storage branch is in a state of no power output. Therefore, by controlling the branch voltage of the energy storage branch to be repaired to be lower than the branch voltage safety value, the branch voltage of the energy storage branch to be repaired can be made within the branch voltage safety value range, thereby reducing the safety impact of the maintenance personnel due to the excessively high voltage of the energy storage branch, and helping to improve the maintenance safety.

[0081] Step S406: controlling the current of the energy storage submodule to be repaired in the energy storage branch to be repaired to be less than the current safety value; and grounding the housing of the energy storage submodule to be repaired.

[0082] An energy storage submodule to be repaired refers to an energy storage submodule that requires repair. In a high-voltage energy storage system, where a single energy storage branch includes multiple cascaded energy storage submodules, one of the energy storage submodules in the energy storage branch to be repaired may be the energy storage submodule to be repaired, or two or more of the energy storage submodules in the energy storage branch to be repaired may be the energy storage submodules to be repaired. In some cases, all of the energy storage submodules in the energy storage branch to be repaired may be the energy storage submodules to be repaired.

[0083] The current safety value refers to the current value of the energy storage submodule, assuming maintenance personnel can enter the energy storage submodule environment. In other words, if the current of the energy storage submodule is within the current safety value, personnel entering the energy storage branch environment will not pose a safety threat to maintenance personnel. While there may be some impact on maintenance personnel's safety, the impact is minimal and within the acceptable safety impact range.

[0084] Since in a high-voltage energy storage system, the energy storage submodule can provide current for power supply, even when the energy storage branch has no power output and the branch voltage is less than the branch voltage safety value, a high current may still exist in the energy storage submodule. Therefore, by controlling the current of the energy storage submodule to be repaired to be less than the current safety value, the safety impact of the excessive current of the energy storage submodule to be repaired on the maintenance personnel is reduced, which helps to improve the maintenance safety. Moreover, in a high-voltage energy storage system, the energy storage submodule is generally large in size, and maintenance personnel need to enter the interior of the energy storage submodule for maintenance. The shell of the energy storage submodule may have a high voltage to ground. Therefore, by grounding the shell of the energy storage submodule to be repaired, the shell voltage of the energy storage submodule to be repaired is reduced to the ground potential, which enables maintenance personnel to safely enter the interior of the energy storage submodule to be repaired for maintenance, thereby improving maintenance safety.

[0085] Based on the method for controlling a high-voltage energy storage system to enter a maintenance state in the embodiment of the present application as described above, when it is necessary to control the high-voltage energy storage system to enter a maintenance state, the method controls the energy storage branch to be repaired to be in a no-power output state, so that the energy storage branch to be repaired has no power output, and controls the branch voltage of the energy storage branch to be repaired to be less than the branch voltage safety value, so that the energy storage branch to be repaired is in a maintenance preparation state, and controls the current of the energy storage submodule to be repaired in the energy storage branch to be repaired to be less than the current safety value, so that the current caused by the battery in the energy storage submodule to be repaired can be less than the current safety value, thereby improving the maintenance safety, and reducing the energy storage submodule to be repaired. The shell is grounded, so that the shell voltage of the energy storage submodule to be repaired is reduced to the ground potential, so as to further improve the maintenance safety. After the above operation, the energy storage branch to be repaired can be put into a no-power output state, the branch voltage of the energy storage branch to be repaired is within the range of the branch voltage safety value, the current in the energy storage submodule to be repaired is within the range of the current safety value, and the shell voltage of the energy storage submodule to be repaired is reduced to the ground potential, thereby reducing the safety problems caused by the energy storage branch to be repaired and the energy storage submodule to be repaired in the energy storage branch being in a high-voltage state, so that the high-voltage energy storage system can enter a state where maintenance personnel can perform on-site maintenance, thereby improving the safety of maintenance.

[0086] Among them, in the method of the above embodiment, the execution order of each step is not limited. For example, it can be that the energy storage branch to be repaired is first controlled to be in a no-power output state, and the branch voltage of the energy storage branch to be repaired is less than the branch voltage safety value, and then the current of the energy storage sub-module to be repaired in the energy storage branch to be repaired is controlled to be less than the current safety value. It can also be that the current of the energy storage sub-module to be repaired in the energy storage branch to be repaired is first controlled to be less than the current safety value, and then the branch voltage of the energy storage branch to be repaired is controlled to be less than the branch voltage safety value. As long as the busbar of the energy storage branch does not charge the energy storage branch to be repaired during the above control process, it is sufficient.

[0087] For the purpose of simplicity of explanation, in the following embodiments, an example is given in which the energy storage branch to be repaired is first controlled to be in a no-power output state, the branch voltage of the energy storage branch to be repaired is less than the branch voltage safety value, and then the current of the energy storage sub-module to be repaired in the energy storage branch to be repaired is controlled to be less than the current safety value. However, this does not strictly limit the execution order of the various steps.

[0088] In step S402, the method for controlling the energy storage branch to be repaired to be in a no-power output state is not limited. In some embodiments, controlling the energy storage branch to be repaired to be in a no-power output state includes: controlling the branch current of the energy storage branch to be repaired to be 0. In the case where the branch current of the energy storage branch to be repaired is 0, based on the power determination method, since there is no branch current, the energy storage branch to be repaired has no power output, and thus by making the branch current of the energy storage branch to be repaired 0, that is, there is no current output as a whole, the energy storage branch to be repaired is in a no-power output state, which can make the energy storage branch to be repaired in a maintenance preparation state to improve safety.

[0089] In some embodiments, controlling the energy storage branch to be repaired to be in a no-power output state includes: controlling the energy storage branch to be repaired to be in a locked state so that the branch current of the energy storage branch to be repaired is less than a preset value.

[0090] Among them, the locked state refers to the state where the energy storage branch is not working. When the energy storage branch is not working, the energy storage branch as a whole has no current output, so that the branch current of the energy storage branch to be repaired can be less than a preset value.

[0091] There is no limitation on the specific setting method of the preset value, as long as the branch current of the energy storage branch is the preset value or less than the preset value, the branch current of the energy storage branch is in a state of no power output as a whole.

[0092] Based on the solution of this embodiment, by controlling the energy storage branch to be repaired to be in a locked state, when the energy storage branch to be controlled is in a locked state, theoretically no branch current flows through the energy storage branch to be repaired, that is, there is no current output as a whole, the branch current is less than a preset value, and it is in a no-power output state. The control method is simple and convenient, and the operability is strong.

[0093] Among them, the method of controlling the energy storage branch to be repaired to be in a locked state is not limited. In some embodiments, controlling the energy storage branch to be repaired to be in a locked state includes: sending a locking instruction to the branch controller of the energy storage branch to be repaired, and the locking instruction is used to control the energy storage branch to be repaired to stop switching, so that the energy storage branch to be repaired is in a locked state.

[0094] A locking instruction refers to an instruction used to control the energy storage branch to enter a locked state. Whether the energy storage branch is in the locked state can be controlled based on the branch controller of the energy storage branch. Therefore, by sending a locking instruction to the branch controller of the energy storage branch to be repaired, the branch controller can control the energy storage branch to be repaired to stop switching, so that the energy storage branch to be repaired is in a locked state.

[0095] Therefore, when the energy storage branch to be repaired is controlled to be in a locked state, it can be achieved by sending a locking instruction to the branch controller of the energy storage branch to be repaired. The energy storage branch to be repaired can stop switching based on the locking instruction, so that the energy storage branch to be repaired is in a locked state. At this time, the branch current of the energy storage branch to be repaired is less than the preset value, that is, there is no current output as a whole, and it is in a no-power output state. The control method is simple and convenient, and the operability is strong.

[0096] In a high-voltage energy storage system, the branch controller can be a standalone controller or comprise multiple submodule controllers, with each submodule controller corresponding to at least one energy storage submodule, i.e., one submodule controller controls one or more energy storage submodules. The number of submodule controllers can be the same as the number of energy storage submodules, i.e., a one-to-one correspondence exists between each submodule controller and each energy storage submodule, with each submodule controller controlling a corresponding energy storage submodule. It should be understood that in actual technical implementations, redundant configurations may also be employed.

[0097] Taking the branch controller including multiple sub-module controllers as an example, sending a locking instruction to the branch controller of the energy storage branch to be overhauled, the locking instruction is used to control the energy storage branch to be overhauled to stop switching so that the energy storage branch to be overhauled is in a locked state, which may include: sending a locking instruction to the sub-module controller of the energy storage sub-module of the energy storage branch to be overhauled, the locking instruction is used to instruct the sub-module controller to turn off the IGBT (Insulated Gate Bipolar Transistor) of the power module in the energy storage sub-module, the branch controller includes a sub-module controller.

[0098] The locking instruction sent to the sub-module controller can be used to control the sub-module controller to shut down the IGBT of the power module in each energy storage sub-module controlled by the sub-module controller, so that the energy storage sub-module is in a locked state, and then the energy storage branch to be repaired including the energy storage sub-module is in a locked state.

[0099] The structural block diagram of the energy storage submodule in some embodiments is shown in Figure 5. The IGBT of the power module of the energy storage submodule is turned off, specifically IGBT2 as shown in Figure 5. After IGBT2 is turned off, when the energy storage submodule is cascaded with other energy storage submodules through terminal 1 and terminal 2, it is through the cascade of the turned-off IGBT2, thereby achieving the locking of the energy storage submodule.

[0100] Therefore, when a locking instruction is sent to the branch controller of the energy storage branch to be repaired to control the energy storage branch to be repaired to stop switching, the submodule controller can be specifically instructed to turn off the IGBT of the power module in the energy storage submodule. That is, by turning off the IGBT of the power module in the energy storage submodule, the energy storage submodule of the energy storage branch to be repaired can be stopped from switching, so that the branch current of the energy storage branch to be repaired is 0. The control method is simple and convenient, and the operability is strong.

[0101] In some embodiments, controlling the energy storage branch to be repaired to be in a no-power output state may include: controlling the energy storage branch to be repaired to be in a short-circuit state so that the energy storage branch to be repaired is in a no-power output state.

[0102] In some application scenarios, the energy storage submodule is provided with a switch K in parallel on both sides of the IGBT2 used for series connection of the energy storage submodule, as shown in FIG5 . Thus, by closing the switch K in the energy storage submodule, the IGBT2 used for series connection of the energy storage submodule can be short-circuited, thereby controlling the energy storage branch to be repaired to be in a short-circuit state, which is simple and convenient to operate.

[0103] In some embodiments, referring to FIG6 , after controlling the energy storage branch to be repaired to be in a no-power output state and before controlling the voltage of the energy storage branch to be repaired to be less than a branch voltage safety value, the following steps are also included.

[0104] Step S4031: Control the energy storage branch to be repaired to be in an isolated and tripped state.

[0105] The energy storage branch to be repaired is in an isolated and tripped state, meaning that the power supply to the energy storage branch to be repaired is cut off and no small current flows through it. When the energy storage branch to be repaired is in a no-power output state, the energy storage branch to be repaired as a whole has no current output. However, in actual technical scenarios, the energy storage branch to be repaired is still connected to the power supply, which may cause leakage current and affect the safety of the repair. Therefore, by isolating and tripping the energy storage branch to be repaired, the current of the energy storage branch to be repaired can be isolated and disconnected, thereby further improving the safety of the repair state.

[0106] There is no limitation on the method of controlling the energy storage branch to be repaired to be in an isolated and tripped state. In some embodiments, controlling the energy storage branch to be repaired to be in an isolated and tripped state includes: controlling the isolating switch of the energy storage branch to be repaired to be in an open state.

[0107] In the energy storage branch, an isolating switch is usually provided to reduce the impact of the fault through the isolating switch when a fault occurs, or to change the system operation wiring mode through the isolating switch.

[0108] In the energy storage branch, only one or two isolating switches may be provided. Typically, when the negative busbar of the energy storage branch is grounded, an isolating switch may be provided only on the positive busbar side of the energy storage branch to isolate the influence of the positive busbar voltage. It should be understood that when the negative busbar of the energy storage branch is grounded, isolating switches may also be provided on both the positive and negative busbar sides of the energy storage branch. As shown in FIG2 , the isolating switch is the isolating switch provided.

[0109] By controlling the isolating switch of the energy storage branch to be repaired to be in the open state, the energy storage branch to be repaired can be controlled to be in the isolated and open state, which can reduce the possibility of current passing through the energy storage branch to be repaired, so as to further improve the safety of maintenance. The control method is simple and convenient, does not require the introduction of additional equipment, and has strong operability.

[0110] After controlling the isolating switch of the energy storage branch to be repaired to be in the open state, the method may further include: detecting the isolating switch state of the isolating switch of the energy storage branch to be repaired, and determining whether the isolating switch is correctly opened according to the isolating switch state.

[0111] Among them, the method of detecting the isolating switch status of the isolating switch is not limited, as long as it can detect whether the isolating switch is in the open state. The embodiment of the present application does not impose any specific restrictions on this.

[0112] Therefore, after performing the work of opening the isolating switch of the energy storage branch to be repaired, the isolating switch status of the isolating switch of the energy storage branch to be repaired is further detected to confirm whether the isolating switch of the energy storage branch to be repaired has been correctly opened, so as to further improve the safety of maintenance.

[0113] In some embodiments, referring to FIG7 , after controlling the energy storage branch to be repaired to be in a no-power output state and before controlling the branch voltage of the energy storage branch to be repaired to be less than the branch voltage safety value, it may also include: Step S4032: controlling the energy storage branch to be repaired to be in a disconnected state.

[0114] The energy storage branch to be repaired is in a disconnected state, which means that the energy storage branch to be repaired is disconnected from the power supply. When the energy storage branch to be repaired is in a no-power output state, the energy storage branch to be repaired as a whole has no current output. However, in actual technical scenarios, the energy storage branch to be repaired is still connected to the power supply, which can easily cause current to flow in the energy storage branch to be repaired due to power supply fluctuations or other conditions, affecting the safety of maintenance. Therefore, by disconnecting the energy storage branch to be repaired, the energy storage branch to be repaired is controlled to be in a disconnected state, so that the energy storage circuit to be repaired is in a disconnected state, reducing the possibility of current flowing due to the energy storage circuit to be repaired not being disconnected, and further improving maintenance safety.

[0115] There are various ways to control the energy storage branch to be repaired to be in a disconnected state. Several of these ways are described below with examples.

[0116] In some embodiments, controlling the energy storage branch to be repaired to be in a disconnected state includes: controlling a circuit breaker of the energy storage branch to be repaired to be in an open state.

[0117] A circuit breaker refers to a switching device that can close, carry and disconnect current under normal or abnormal circuit conditions. Therefore, when a circuit breaker is installed on the energy storage branch to be repaired, the current of the energy storage branch to be repaired can be disconnected by controlling the circuit breaker of the energy storage branch to be repaired to be in the open state, thereby further improving the safety of the maintenance state.

[0118] After controlling the circuit breaker of the energy storage branch to be repaired to be in an open state, the method may further include: detecting the circuit breaker state of the circuit breaker of the energy storage branch to be repaired, and determining whether the circuit breaker is correctly opened according to the circuit breaker state.

[0119] There is no limitation on the method of detecting the circuit breaker state of the circuit breaker, as long as it can detect whether the circuit breaker is in the open state. The embodiment of the present application does not impose any specific limitation on this.

[0120] Therefore, after executing the work of controlling the circuit breaker of the energy storage branch to be repaired to be in the open state, the circuit breaker state of the circuit breaker of the energy storage branch to be repaired is further detected to determine whether the circuit breaker of the energy storage branch to be repaired has been correctly opened, so as to further improve the safety of maintenance.

[0121] In some embodiments, controlling the energy storage branch to be repaired to be in a disconnected state includes: controlling a fast switch of the energy storage branch to be repaired to be in an open state.

[0122] A fast switch is a switching device that can quickly close, carry, and interrupt current under normal or abnormal circuit conditions. In high-voltage energy storage systems, fast switches can quickly cut off fault currents in the event of a fault, with rapid opening and closing speeds. Therefore, when it is necessary to disconnect an energy storage branch under maintenance, the fast switch of the energy storage branch under maintenance can be controlled to be in the open state. This provides a fast response and opening speed, meeting the need to disconnect the energy storage branch under maintenance, improving maintenance safety, and helping to improve maintenance efficiency.

[0123] After controlling the fast switch of the energy storage branch to be repaired to be in the open state, the method may further include: detecting the fast switch state of the fast switch of the energy storage branch to be repaired, and determining whether the fast switch is correctly opened according to the fast switch state.

[0124] There is no limitation on the method for detecting the fast switch state of the fast switch, as long as it is possible to detect whether the fast switch is in the open state. The embodiment of the present application does not impose any specific limitation on this.

[0125] Therefore, after executing the work of controlling the fast switch of the energy storage branch to be repaired to be in the open state, the fast switch state of the fast switch of the energy storage branch to be repaired is further detected to confirm whether the fast switch of the energy storage branch to be repaired has been correctly opened, so as to further improve the safety of maintenance.

[0126] There is no limitation on the manner of controlling the voltage of the energy storage branch to be repaired to be lower than the branch voltage safety value. Some of these implementations are described below with examples.

[0127] In some embodiments, controlling the voltage of the energy storage branch to be repaired to be lower than the branch voltage safety value may include: performing voltage reduction processing through a step-down module of the energy storage branch to be repaired so that the voltage of the energy storage branch to be repaired is lower than the branch voltage safety value.

[0128] The step-down module can also be called a step-down converter, a step-down regulator, a step-down inverter, etc., which can convert the input voltage into a lower voltage output. Among them, the setting position of the step-down module on the energy storage branch to be repaired is not limited, for example, it can be set on the side of the positive bus of the energy storage branch to be repaired. When the energy storage branch is working normally, the step-down module can be in a bypass state, or in a non-enabled state, and the energy storage branch can work normally. When the high-voltage energy storage system needs to enter the maintenance state, it is necessary to reduce the voltage of the energy storage branch to be repaired to less than the branch voltage safety value. The step-down module is enabled, and the voltage reduction processing of the step-down module is used to make the voltage of the energy storage branch to be repaired less than the branch voltage safety value. Among them, the specific parameter setting method of the step-down module is not limited, as long as the output voltage after the step-down module is reduced is less than the branch voltage safety value.

[0129] Based on this embodiment, a step-down module can be configured for the energy storage branch. During the normal operation of the energy storage branch, the step-down module is not enabled. When it is necessary to enter the maintenance state for maintenance and it is necessary to control the voltage of the energy storage branch to be repaired to be lower than the branch voltage safety value, the step-down module is enabled to perform voltage reduction processing through the step-down module so that the voltage of the energy storage branch to be repaired is lower than the branch voltage safety value, thereby improving maintenance safety.

[0130] In other embodiments, controlling the voltage of the energy storage branch to be repaired to be less than a branch voltage safety value may include: controlling the energy storage branch to be repaired to be grounded.

[0131] The grounding of the energy storage branch to be repaired means that the potential of the energy storage branch to be repaired is at the ground potential. Under normal circumstances, the ground potential is a very low potential that can meet safety requirements. Under the ground potential (ground voltage), there will be no safety problems when personnel enter. In this case, the voltage of the energy storage branch to be repaired can be made lower than the branch voltage safety value.

[0132] Based on this embodiment, since most high-voltage energy storage systems are series systems, when not grounded, the system voltage and the shell voltage of each submodule are still in a suspended state. Therefore, when it is necessary to control the voltage of the energy storage branch to be repaired to be lower than the branch voltage safety value, by controlling the grounding switch of the energy storage branch to be repaired to be closed, one or both ends of the grounding switch of the energy storage branch to be repaired can be at the ground potential, which can further improve safety and the control method is simple and convenient.

[0133] There is no limitation on the method of controlling the grounding of the energy storage branch to be repaired, as long as the energy storage branch to be repaired can be placed in a grounded state.

[0134] In some embodiments, controlling the energy storage branch to be repaired to be grounded may include: controlling the grounding switch of the energy storage branch to be repaired to be closed.

[0135] In a high-voltage energy storage system, a grounding switch is usually provided on the energy storage branch to ground the energy storage branch through the grounding switch when needed (such as when a fault occurs). Among them, in the energy storage branch, only one grounding switch can be provided, or two grounding switches can be provided. Normally, when the negative busbar of the energy storage branch is grounded, a grounding switch can be provided only on the positive busbar side of the energy storage branch to isolate the influence of the positive busbar voltage. It should be understood that when the negative busbar of the energy storage branch is grounded, grounding switches can also be provided on both the positive busbar side and the negative busbar side of the energy storage branch. As shown in Figure 2, the grounding knife switch is the provided grounding switch.

[0136] Based on this embodiment, when it is necessary to control the grounding of the energy storage branch to be repaired, by controlling the closing of the grounding switch of the energy storage branch to be repaired, one or both ends of the grounding switch of the energy storage branch to be repaired can be at the ground potential, which can further improve safety. The control method is simple and convenient, and no additional devices are required.

[0137] After controlling the grounding switch of the energy storage branch to be repaired to be closed, the method may further include: detecting a grounding switch state of the grounding switch of the energy storage branch to be repaired, and determining whether the grounding switch is correctly closed according to the grounding switch state.

[0138] There is no limitation on the method of inspecting the grounding switch status of the grounding switch, as long as it is possible to detect whether the grounding switch is in the open state. The embodiment of the present application does not impose any specific limitation on this.

[0139] Therefore, after executing the work of controlling the closing of the grounding switch of the energy storage branch to be repaired, the grounding state of the grounding switch of the energy storage branch to be repaired is further detected to determine whether the grounding switch of the energy storage branch to be repaired has been correctly closed, so as to further improve the safety of the repair.

[0140] As shown in FIG5 , the energy storage submodule 500 typically includes a connected energy storage battery 501 and a power module 502. As shown in FIG5 , the power module 502 includes a capacitor C, which may have a relatively high voltage, causing current to flow through the energy storage submodule, impacting safety. In some embodiments, as shown in FIG8 , controlling the current of the energy storage submodule to be repaired in the energy storage branch to be repaired to be less than a current safety value may include:

[0141] Step S4060: Control the discharge of the capacitor in the power module of the energy storage submodule to be repaired, so that the current of the energy storage submodule to be repaired in the energy storage branch to be repaired is less than the current safety value.

[0142] Since in the high-voltage energy storage system, the energy storage submodule is large in size and the capacitors in the power module of the energy storage submodule are in a high-voltage state, it is easy for current to flow in the energy storage submodule. Therefore, by controlling the discharge of the capacitors in the power module of the energy storage submodule to be repaired, the voltage of the capacitors in the power module can be reduced, so that the current of the energy storage submodule to be repaired in the energy storage branch to be repaired is less than the current safety value, allowing maintenance personnel to enter the energy storage submodule to be repaired for maintenance, thereby further improving maintenance safety.

[0143] There are various ways to control the current of the energy storage submodule to be repaired in the energy storage branch to be repaired to be less than the current safety value. Some of these ways are described below with examples.

[0144] In some embodiments, the energy storage submodule also includes a discharge module, and the power module is selectively connected to the energy storage battery and the discharge module; controlling the discharge of the capacitor in the power module of the energy storage submodule to be repaired includes: controlling the power module to switch to connection with the discharge module so that the capacitor in the power module is discharged through the discharge module.

[0145] The discharge module is a module that can discharge the capacitor part, and the voltage on the capacitor can be released through the discharge module. Among them, the discharge module can be an independent module. When the energy storage submodule is operating normally, the discharge module is in a bypass state or is not enabled, the power module is not connected to the discharge module, and the energy storage submodule operates normally. When it is necessary to enter the maintenance state and control the discharge of the capacitor in the power module of the energy storage submodule to be repaired, the power module is switched to connect with the discharge module, so that the capacitor in the power module can be discharged through the discharge module.

[0146] Therefore, a special discharge module is set in the energy storage submodule, and the power module is connected to the energy storage battery and the discharge module in a selective manner. During the normal operation of the energy storage submodule, the power module is connected to the energy storage module. When it is necessary to enter the maintenance state for maintenance, the power module is disconnected from the energy storage module and switched to the discharge module. The capacitor of the power module will be discharged through the discharge module, thereby reducing the voltage of the capacitor in the power module, making the current of the energy storage submodule to be repaired in the energy storage branch to be repaired less than the current safety value, so that maintenance personnel can enter the energy storage submodule to be repaired for maintenance, thereby further improving maintenance safety.

[0147] In some embodiments, as shown in Figure 5, the power module includes a capacitor and a resistor; controlling the discharge of the capacitor in the power module of the energy storage submodule to be repaired includes: disconnecting the connection between the energy storage battery of the energy storage submodule to be repaired and the power module, so that the capacitor in the power module discharges to the resistor of the power module.

[0148] After the connection between the energy storage battery and the power module is disconnected, a loop is no longer formed between the energy storage battery and the power module. However, due to the presence of capacitors and resistors in the power module, the capacitors and resistors can form a loop, and the capacitors will discharge the resistors, causing the voltage in the capacitors to decrease.

[0149] In a high-voltage energy storage system, some energy storage submodules are provided with capacitors and resistors. Therefore, by disconnecting the connection between the energy storage battery of the energy storage submodule to be repaired and the power module, the capacitor and resistor in the power module form a loop. Based on the formed loop, the capacitor of the power module will discharge the resistor of the power module, thereby reducing the voltage of the capacitor in the power module, making the current of the energy storage submodule to be repaired in the energy storage branch to be repaired less than the current safety value, allowing maintenance personnel to enter the energy storage submodule to be repaired for maintenance, thereby further improving maintenance safety.

[0150] The method for disconnecting the energy storage battery and the power module of the energy storage submodule to be repaired is not limited. In some embodiments, as shown in Figure 5, a switch 503 can be provided between the energy storage battery and the power module. Because in some cases, multiple energy storage batteries in the energy storage submodule are connected in parallel before being connected to the power module, a switch can be provided between the parallel energy storage batteries and the power module. The type of switch is not limited. In the embodiment of the present application, the switch can be an isolating switch, which can isolate low currents and help further improve safety.

[0151] Accordingly, in some embodiments, taking an isolating switch provided between the energy storage battery and the power module as an example, disconnecting the connection between the energy storage battery and the power module of the energy storage submodule to be repaired may include: disconnecting the isolating switch between the parallel energy storage battery and the power module of the energy storage submodule to be repaired.

[0152] Since there are usually multiple energy storage batteries in the energy storage submodule, and the multiple energy storage batteries are connected to the power module in parallel, when it is necessary to disconnect the energy storage battery of the energy storage submodule to be repaired and the power module, the parallel energy storage batteries of the energy storage submodule to be repaired and the power module can be directly disconnected by disconnecting the isolation switch between the parallel energy storage batteries of the energy storage submodule to be repaired and the power module. This can put the parallel energy storage batteries of the energy storage submodule to be repaired and the power module into a disconnected state, so that the power module is not connected to the parallel energy storage batteries, so that the capacitor and the resistor in the power module form a loop. Based on the formed loop, the capacitor of the power module will discharge the resistor of the power module, so that the voltage of the capacitor in the power module is reduced, so that the current of the energy storage submodule to be repaired in the energy storage branch to be repaired is less than the current safety value. In addition, by disconnecting the isolation switch, a visible breakpoint can be provided, which can improve reliability.

[0153] Among them, after disconnecting the isolating switch between the parallel energy storage battery and the power module of the energy storage submodule to be repaired, the method may also include: detecting the isolating switch status of the isolating switch between the parallel energy storage battery and the power module of the energy storage submodule to be repaired, and determining whether the isolating switch between the parallel energy storage battery and the power module is correctly opened according to the isolating switch status.

[0154] Therefore, after disconnecting the isolating switch between the parallel energy storage battery and the power module of the energy storage submodule to be repaired, the isolating switch status of the isolating switch between the parallel energy storage battery and the power module is further detected to determine whether the isolating switch between the parallel energy storage battery and the power module has been correctly opened, thereby further improving the safety of maintenance.

[0155] As mentioned above, in the energy storage submodule, multiple energy storage batteries are connected in parallel and then connected to the power module. Each energy storage battery has a branch switch, which can be controlled by controlling the opening and closing state of the branch switch to switch whether the energy storage battery is connected. At this time, each energy storage battery can be called a parallel energy storage battery.

[0156] Accordingly, in some embodiments, disconnecting the energy storage battery and the power module of the energy storage submodule to be repaired includes: disconnecting the branch switches of the parallel energy storage batteries.

[0157] Since there are usually multiple energy storage batteries in the energy storage submodule, and these multiple energy storage batteries are connected to the power module in parallel, when it is necessary to disconnect the connection between the energy storage battery of the energy storage submodule to be repaired and the power module, the branch switch of the parallel energy storage battery can be directly disconnected to put the energy storage switch of the parallel energy storage battery into an off state, so that there is no current on the busbar of the energy storage battery, so that the capacitor and the resistor in the power module form a loop. Based on the formed loop, the capacitor of the power module will discharge the resistor of the power module, so that the voltage of the capacitor in the power module is reduced. On this basis, the current of the energy storage submodule to be repaired in the energy storage branch to be repaired can be made less than the current safety value.

[0158] When disconnecting the branch switches of the parallel energy storage batteries, the branch switches of all the energy storage batteries in the energy storage submodule can be disconnected, thereby disconnecting each energy storage battery. Alternatively, the branch switches of a portion of the parallel energy storage batteries in the energy storage submodule can be disconnected. As long as disconnecting only the branch switches of a portion of the parallel energy storage batteries allows the capacitors in the power module to discharge and the current of the energy storage submodule to be repaired to be less than the safe current value, it will be sufficient.

[0159] After disconnecting the branch switches of the parallel energy storage batteries, the method may further include: detecting a branch switch state of the branch switches of the parallel energy storage batteries, and determining whether the branch switches of the parallel energy storage batteries are correctly opened according to the branch switch state.

[0160] Therefore, after performing the work of disconnecting the branch switch of the parallel energy storage battery, the branch switch status of the branch switch of the parallel energy storage battery is further detected to confirm whether the branch switch of the parallel energy storage battery has been correctly opened, so as to further improve the maintenance safety.

[0161] In some embodiments, disconnecting the energy storage battery and the power module of the energy storage submodule to be repaired includes: disconnecting the isolation switch between the parallel energy storage battery and the power module and the branch switch of the parallel energy storage battery.

[0162] Since there are usually multiple energy storage batteries in the energy storage submodule, and these multiple energy storage batteries are connected to the power module in parallel, when it is necessary to disconnect the energy storage battery of the energy storage submodule to be repaired and the power module, both the isolating switch between the parallel energy storage batteries of the energy storage submodule to be repaired and the power module is disconnected, and the branch switch of the parallel energy storage batteries is disconnected. Disconnecting the isolating switch not only provides a visible breakpoint, thereby improving reliability, but also ensures that there is no current on the busbar of the energy storage battery. Through the dual control method, the capacitor and the resistor in the power module form a loop. Based on the formed loop, the capacitor of the power module discharges the resistor of the power module, thereby improving the reliability of disconnecting the energy storage battery of the energy storage submodule to be repaired and the power module, and increasing the possibility of ensuring that the current of the energy storage submodule to be repaired in the energy storage branch to be repaired is less than the current safety value.

[0163] There is no limitation on the method of grounding the shell of the energy storage submodule to be repaired. In some embodiments, grounding the shell of the energy storage submodule to be repaired includes any one of the following: hanging the shell of the energy storage submodule to be repaired on a grounding rod; connecting the shell of the energy storage submodule to be repaired to the ground wire; closing the standby grounding switch of the energy storage submodule to be repaired.

[0164] Grounding rods, also known as grounding electrodes or grounding grids, can improve the internal conductivity of grounding conductors and reduce the external soil resistivity of grounding conductors. They are easy to construct, require little space, are environmentally friendly, have a long service life, and offer low resistance. By hooking the housing of the energy storage submodule to be repaired to the grounding rod, the housing of the energy storage submodule to be repaired can be grounded in a simple and convenient manner.

[0165] The ground wire is connected to the earth, the housing or a conductor with a reference potential of zero. Therefore, the housing of the energy storage submodule to be repaired can be grounded by connecting the housing of the energy storage submodule to be repaired to the ground wire.

[0166] In some application scenarios, the energy storage submodule is provided with a backup grounding switch. Therefore, the shell of the energy storage submodule to be repaired can be grounded by closing the backup grounding switch. The operation is simple and convenient, and no additional equipment is required.

[0167] Therefore, when it is necessary to ground the shell of the energy storage submodule to be repaired, the shell of the energy storage submodule to be repaired can be grounded by hanging the shell of the energy storage submodule to be repaired on a grounding rod, connecting the shell of the energy storage submodule to be repaired to a ground wire, closing the standby grounding switch of the energy storage submodule to be repaired, etc., so that when actually performing the shell grounding operation, it can be selected according to the needs of the scene, which has strong flexibility and operability.

[0168] Based on the above embodiments, some specific examples are provided below for illustration. As shown in FIG9 , when the high-voltage energy storage system needs to be repaired, the high-voltage energy storage system can be put into a repair state in the following manner to repair the high-voltage energy storage system.

[0169] As shown in Figure 9, when the high-voltage energy storage system needs to be repaired, a locking command is first sent to the energy storage branch to be repaired through the valve control system. The energy storage branch stops switching, and the IGBT of the energy storage submodule is turned off. At this time, the branch current of the energy storage branch is less than the preset value. Theoretically, the branch current of the energy storage branch is 0, and the energy storage branch as a whole is in a locked state.

[0170] When the energy storage branch is locked, leakage current may occur. By controlling the fast switch of the energy storage branch under maintenance to the open state, the system leakage current of the energy storage branch under maintenance can be quickly disconnected, and a break visible in the air can be provided. After controlling the fast switch to the open state, the state of the fast switch of the energy storage branch can also be checked to determine whether it is in the open state to confirm whether the fast switch has been opened correctly.

[0171] The fast switch can quickly disconnect the system leakage current of the energy storage branch under maintenance, and further disconnect the isolating switch of the energy storage branch under maintenance to prevent current from flowing through the energy storage branch. After disconnecting the isolating switch, the isolating switch of the energy storage branch under maintenance is also checked to see if it is in the open state to confirm whether the isolating switch has been opened correctly.

[0172] The grounding switch of the energy storage branch to be repaired is controlled to close so that the branch voltage of the energy storage branch is less than the branch voltage safety value. For example, if the branch voltage safety value is 50V, the branch voltage is less than 50V, for example, at ground potential or zero potential. The grounding switch of the energy storage branch can be a grounding switch adjacent to the isolating switch, close to the side of the energy storage branch. Because the energy storage branch includes energy storage submodules connected in series, if it is not grounded, the branch voltage of the energy storage branch and the housing voltage of each energy storage submodule remain suspended, posing a danger to maintenance personnel. Closing the grounding switch of the energy storage branch can set a ground reference potential so that one or both ends of the energy storage branch (depending on the system configuration) with the grounding switch are at zero potential. After closing the grounding switch of the energy storage branch to be repaired, a status check can be performed on the grounding switch to determine whether it is in the closed state, thereby confirming that the grounding switch has been properly closed.

[0173] After performing the above operations, the whole machine enters the maintenance preparation state, and the energy storage submodule that needs to be repaired (i.e., the energy storage submodule to be repaired) can be operated to put the submodule to be repaired into the maintenance state to meet the maintenance requirements.

[0174] Taking the example of an isolating switch provided between the parallel energy storage battery and the power module, the isolating switch between the parallel energy storage battery and the power module is disconnected. The isolating switch is provided at the wiring position between the power module and the parallel energy storage battery. As shown in FIG5 , since there is a capacitor in the power module connected in parallel with the energy storage battery, in order to improve the safety of maintenance, it is necessary to discharge the capacitor. By disconnecting the isolating switch between the parallel energy storage battery and the power module, the capacitor in the power module of the energy storage submodule can be discharged to the resistor, so that the current in the energy storage submodule is less than the current safety value, that is, the leakage current of the energy storage submodule is less than the current safety value, so that there is no leakage current caused by the battery in the energy storage submodule. After disconnecting the isolating switch between the parallel energy storage battery and the power module, the state of the isolating switch can also be detected to detect whether the isolating switch is in the open state to confirm whether the isolating switch has been correctly opened.

[0175] Subsequently, the housing of the energy storage submodule to be repaired is grounded, reducing the voltage of the housing to ground potential. After grounding the housing of the energy storage submodule to be repaired, the housing voltage (platform voltage) of the repair submodule can be further measured to detect whether the housing voltage is at ground potential or zero potential, further improving repair safety.

[0176] After the above operations, the operator can intervene in the energy storage submodule of the high-voltage energy storage system on site for maintenance.

[0177] It should be understood that, although the various steps in the flowcharts involved in the various embodiments described above are displayed in sequence according to the instructions of the arrows, these steps are not necessarily executed in sequence in the order indicated by the arrows. Unless otherwise specified herein, there is no strict order restriction on the execution of these steps, and these steps can be executed in other orders. Moreover, at least a portion of the steps in the flowcharts involved in the various embodiments described above can include multiple steps or multiple stages, and these steps or stages are not necessarily executed and completed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a portion of steps or stages in other steps.

[0178] Based on the same inventive concept, an embodiment of the present application further provides a device for controlling a high-voltage energy storage system to enter a maintenance state, which is used to implement the aforementioned method for controlling a high-voltage energy storage system to enter a maintenance state. The solution provided by this device is similar to the solution described in the aforementioned method. Therefore, the specific limitations of one or more embodiments of the device for controlling a high-voltage energy storage system to enter a maintenance state provided below can be found in the aforementioned method for controlling a high-voltage energy storage system to enter a maintenance state, and will not be repeated here.

[0179] In one embodiment, as shown in FIG10 , a device for controlling a high-voltage energy storage system to enter a maintenance state is provided, wherein the high-voltage energy storage system includes at least one energy storage branch, and the energy storage branch includes a plurality of cascaded energy storage sub-modules; the device includes: a branch control module 101 and a sub-module control module 102, wherein: the branch control module 101 is used to control the energy storage branch to be maintained to be in a no-power output state, and to control the voltage of the energy storage branch to be maintained to be less than a branch voltage safety value; the sub-module control module 102 is used to control the current safety value of the energy storage sub-module to be maintained in the energy storage branch to be maintained, and to ground the shell of the energy storage sub-module to be maintained.

[0180] In some embodiments, the branch control module 101 is used to control the energy storage branch to be repaired to be in a locked state, so that the branch current of the energy storage branch to be repaired is less than a preset value.

[0181] In some embodiments, the branch control module 101 is further used to control the energy storage branch to be repaired to be in an isolated and tripped state after the energy storage branch to be repaired is in a no-power output state and before the voltage of the energy storage branch to be repaired is less than the branch voltage safety value.

[0182] In some embodiments, the branch control module 101 is further used to control the energy storage branch to be repaired to be in a no-power output state, and before controlling the branch voltage of the energy storage branch to be repaired to be less than the branch voltage safety value, and also includes: controlling the energy storage branch to be repaired to be in a disconnected state.

[0183] In some embodiments, the branch control module 101 is further configured to control the fast switch of the energy storage branch to be repaired to be in an open state, so as to control the energy storage branch to be repaired to be in a disconnected state.

[0184] In some embodiments, the branch control module 101 is configured to perform voltage reduction processing through the voltage reduction module of the energy storage branch to be repaired, so that the voltage of the energy storage branch to be repaired is less than the branch voltage safety value.

[0185] In some embodiments, the branch control module 101 is used to control the grounding of the energy storage branch to be repaired, so as to control the voltage of the energy storage branch to be repaired to be lower than the branch voltage safety value.

[0186] In some embodiments, the energy storage submodule includes an energy storage battery and a power module, and the submodule control module 102 is used to control the discharge of the capacitor in the power module of the energy storage submodule to be repaired so that the current of the energy storage submodule to be repaired in the energy storage branch to be repaired is less than the current safety value.

[0187] In some embodiments, the energy storage submodule also includes a discharge module, and the power module is selectively connected to either the energy storage battery or the discharge module; the submodule control module 102 is used to control the power module to switch to connection with the discharge module so that the capacitor in the power module is discharged through the discharge module.

[0188] In some embodiments, the power module includes capacitors and resistors; the submodule control module 102 is used to disconnect the energy storage battery of the energy storage submodule to be repaired and the power module so that the capacitor in the power module discharges to the resistor of the power module.

[0189] In some embodiments, the submodule control module 102 is configured to disconnect the isolation switch between the parallel energy storage battery and the power module and the branch switch of the parallel energy storage battery to disconnect the connection between the energy storage battery and the power module of the energy storage submodule to be repaired.

[0190] In some embodiments, the submodule control module 102 is used to ground the shell of the energy storage submodule to be repaired by any of the following methods: hanging the shell of the energy storage submodule to be repaired to a grounding rod; connecting the shell of the energy storage submodule to be repaired to the ground wire; closing the standby grounding switch of the energy storage submodule to be repaired.

[0191] Each module in the aforementioned apparatus for controlling the high-voltage energy storage system to enter a maintenance state may be implemented in whole or in part through software, hardware, or a combination thereof. Each module may be embedded in or independent of a processor within a computer device in hardware form, or may be stored in a computer device memory in software form, so that the processor can call and execute the corresponding operations of each module.

[0192] In one embodiment, a computer device is provided, which may be a server, and its internal structure diagram may be as shown in FIG11 . The computer device includes a processor, a memory, and a network interface connected via a system bus. The processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program, and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The database of the computer device is used to store data related to controlling the high-voltage energy storage system to enter a maintenance state, such as the above-mentioned processing logic for controlling the high-voltage energy storage system to enter a maintenance state, etc. The network interface of the computer device is used to communicate with an external terminal via a network connection. When the computer program is executed by the processor, a method for controlling a high-voltage energy storage system to enter a maintenance state is implemented.

[0193] Those skilled in the art will understand that the structure shown in FIG11 is merely a block diagram of a portion of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than shown in the figure, or combine certain components, or have a different arrangement of components.

[0194] In one embodiment, a computer device is provided, including a memory and a processor. The memory stores a computer program, and when the processor executes the computer program, the steps of the method for controlling a high-voltage energy storage system to enter a maintenance state in any of the embodiments described above are implemented.

[0195] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the steps of the method for controlling a high-voltage energy storage system to enter a maintenance state in any of the embodiments described above are implemented.

[0196] In one embodiment, a computer program product is provided, comprising a computer program, which, when executed by a processor, implements the steps of the method for controlling a high-voltage energy storage system to enter a maintenance state in any of the above-described embodiments.

[0197] Those skilled in the art will appreciate that all or part of the processes in the above-mentioned embodiment methods can be implemented by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, database or other media used in the embodiments provided in this application may include at least one of non-volatile and volatile memory. Non-volatile memory may include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory may include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The database involved in the various embodiments provided herein may include at least one of a relational database and a non-relational database. Non-relational databases may include, but are not limited to, distributed databases based on blockchains. The processor involved in the various embodiments provided herein may be, but are not limited to, a general-purpose processor, a central processing unit, a graphics processing unit, a digital signal processor, a programmable logic unit, a data processing logic unit based on quantum computing, and the like.

[0198] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0199] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, and these modifications and improvements fall within the scope of protection of the present application. Therefore, the scope of protection of the present application shall be determined by the appended claims.

Claims

1. A method for controlling a high-voltage energy storage system to enter a maintenance state, wherein the high-voltage energy storage system includes at least one energy storage branch, and the energy storage branch includes a plurality of cascaded energy storage submodules; wherein: The method comprises: Control the energy storage branch to be repaired to be in a no-power output state; Controlling the branch voltage of the energy storage branch to be repaired to be less than a branch voltage safety value; The current of the energy storage submodule to be repaired in the energy storage branch to be repaired is controlled to be less than a current safety value; and the shell of the energy storage submodule to be repaired is grounded.

2. The method according to claim 1, wherein The step of controlling the energy storage branch to be repaired to be in a no-power output state includes: The energy storage branch to be repaired is controlled to be in a locked state so that the branch current of the energy storage branch to be repaired is less than a preset value.

3. The method according to claim 1 or 2, wherein: After controlling the energy storage branch to be repaired to be in a no-power output state and before controlling the voltage of the energy storage branch to be repaired to be less than a branch voltage safety value, the method further includes: The energy storage branch to be repaired is controlled to be in an isolated and open state.

4. The method according to any one of claims 1 to 3, wherein: After controlling the energy storage branch to be repaired to be in a no-power output state and before controlling the branch voltage of the energy storage branch to be repaired to be less than a branch voltage safety value, the method further includes: The energy storage branch to be repaired is controlled to be in a disconnected state.

5. The method according to claim 4, wherein The controlling the energy storage branch to be repaired to be in a disconnected state includes: The fast switch of the energy storage branch to be repaired is controlled to be in an open state.

6. The method according to any one of claims 1 to 5, wherein: The controlling the voltage of the energy storage branch to be repaired to be less than a branch voltage safety value includes: The voltage reduction module of the energy storage branch to be repaired is used to perform voltage reduction processing so that the voltage of the energy storage branch to be repaired is less than the branch voltage safety value.

7. The method according to any one of claims 1 to 5, wherein: The controlling the voltage of the energy storage branch to be repaired to be less than a branch voltage safety value includes: Control the energy storage branch to be repaired to be grounded.

8. The method according to any one of claims 1 to 7, wherein: The energy storage submodule includes an energy storage battery and a power module, and the controlling the current of the energy storage submodule to be repaired in the energy storage branch to be repaired to be less than the current safety value includes: The capacitor in the power module of the energy storage submodule to be repaired is controlled to discharge, so that the current of the energy storage submodule to be repaired in the energy storage branch to be repaired is less than the current safety value.

9. The method according to claim 8, wherein The energy storage submodule further includes a discharge module, and the power module is connected to either the energy storage battery or the discharge module; The controlling the discharge of the capacitor in the power module of the energy storage submodule to be repaired includes: The power module is controlled to switch to be connected to the discharge module, so that the capacitor in the power module is discharged through the discharge module.

10. The method according to claim 8, wherein The power module includes a capacitor and a resistor; The controlling the discharge of the capacitor in the power module of the energy storage submodule to be repaired includes: The connection between the energy storage battery of the energy storage submodule to be repaired and the power module is disconnected, so that the capacitor in the power module discharges to the resistance of the power module.

11. The method according to claim 10, wherein: Disconnecting the connection between the energy storage battery and the power module of the energy storage submodule to be repaired includes: Disconnect the isolation switch between the parallel energy storage battery and the power module and the branch switch of the parallel energy storage battery.

12. The method according to any one of claims 1 to 11, wherein: Grounding the housing of the energy storage submodule to be repaired includes any one of the following: Hanging the shell of the energy storage submodule to be repaired on a grounding rod; Connecting the housing of the energy storage submodule to be repaired to the ground wire; Close the standby grounding switch of the energy storage submodule to be repaired.

13. A device for controlling a high-voltage energy storage system to enter a maintenance state, wherein: The high-voltage energy storage system includes at least one energy storage branch, which includes a plurality of cascaded energy storage submodules; the device includes a branch control module and a submodule control module: The branch control module is used to control the energy storage branch to be repaired to be in a no-power output state, and to control the voltage of the energy storage branch to be repaired to be less than a branch voltage safety value; The submodule control module is used to control the current safety value of the energy storage submodule to be repaired in the energy storage branch to be repaired, and to ground the shell of the energy storage submodule to be repaired.

14. The device according to claim 13, wherein The branch control module is used to control the energy storage branch to be repaired to be in a locked state so that the branch current of the energy storage branch to be repaired is less than a preset value.

15. The device according to claim 13 or 14, wherein The branch control module is also used to control the energy storage branch to be repaired to be in an isolated and disconnected state after the energy storage branch to be repaired is in a no-power output state and before the voltage of the energy storage branch to be repaired is less than the branch voltage safety value.

16. The device according to any one of claims 13 to 15, wherein: The branch control module is also used to control the energy storage branch to be repaired to be in a disconnected state after the energy storage branch to be repaired is in a no-power output state and before the branch voltage of the energy storage branch to be repaired is less than the branch voltage safety value.

17. The device according to claim 16, wherein The branch control module is also used to control the fast switch of the energy storage branch to be repaired to be in the open state, so as to control the energy storage branch to be repaired to be in the disconnected state.

18. The device according to any one of claims 13 to 17, wherein: The branch control module is used to perform voltage reduction processing through the voltage reduction module of the energy storage branch to be repaired, so that the voltage of the energy storage branch to be repaired is less than the branch voltage safety value.

19. The device according to any one of claims 13 to 17, wherein: The branch control module is used to control the grounding of the energy storage branch to be repaired, so as to control the voltage of the energy storage branch to be repaired to be lower than the branch voltage safety value.

20. The device according to any one of claims 13 to 19, wherein The energy storage submodule includes an energy storage battery and a power module. The submodule control module is used to control the discharge of the capacitor in the power module of the energy storage submodule to be repaired, so that the current of the energy storage submodule to be repaired in the energy storage branch to be repaired is less than the current safety value.

21. The device according to claim 20, wherein The energy storage submodule also includes a discharge module, and the power module is connected to either the energy storage battery or the discharge module; the submodule control module is used to control the power module to switch to connection with the discharge module so that the capacitor in the power module is discharged through the discharge module.

22. The device according to claim 20, wherein The power module includes capacitors and resistors; the submodule control module is used to disconnect the energy storage battery of the energy storage submodule to be repaired and the power module, so that the capacitor in the power module discharges to the resistor of the power module.

23. The device according to claim 22, wherein The submodule control module is used to disconnect the isolation switch between the parallel energy storage battery and the power module and the branch switch of the parallel energy storage battery to disconnect the connection between the energy storage battery and the power module of the energy storage submodule to be repaired.

24. The device according to any one of claims 13 to 23, wherein: The submodule control module is used to ground the housing of the energy storage submodule to be repaired by any of the following methods: Hang the shell of the energy storage submodule to be repaired on the grounding rod; Connect the housing of the energy storage submodule to be repaired to the ground wire; Close the backup grounding switch of the energy storage submodule to be repaired.

25. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 12 are implemented.

26. A computer-readable storage medium having a computer program stored thereon, wherein: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 12 are implemented.

27. A computer program product comprising a computer program, wherein When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 12 are implemented.

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