High-voltage direct-connected energy storage system, and control method and device for energy storage device

Abstract

The present application relates to a high-voltage direct-connected energy storage system, and a control method and device for an energy storage device. The high-voltage direct-connected energy storage system may comprise: a clamping circuit; an energy storage device, comprising a first energy storage trunk line, at least two energy storage submodules connected to the first energy storage trunk line, at least one dielectric branch, a first node arranged on the first energy storage trunk line, and a first grounding circuit connected to the first node, wherein the resistance value of the first grounding circuit is less than a preset resistance threshold; and a control device used for controlling, on the basis of an expected voltage of the energy storage device and measured voltages of the at least two energy storage submodules connected to the first energy storage trunk line, each target energy storage implementation submodule on two sides of the first node to be in an activated state. The embodiments of the present application can improve the voltage stability at two ends of the energy storage device, thereby facilitating the improvement of the operational reliability of components in the energy storage device.

Description

High-voltage direct-mounted energy storage system, energy storage device control method and control device

[0001] Cross-references

[0002] This application refers to Chinese Patent Application No. 2023112138261, filed on September 19, 2023, entitled “Energy Storage Valve, Control Method, Control Device and Energy Storage Device,” which is incorporated herein by reference in its entirety. Technical Field

[0003] The present application relates to the field of energy storage technology, and in particular to a high-voltage direct-mounted energy storage system, a control method for an energy storage device, and a control device. Background Art

[0004] With the development of energy storage technology, DC direct-hung energy storage devices have become a common device in energy storage technology. DC direct-hung energy storage devices can exchange energy with the DC grid independently, or they can cooperate with other devices (such as converter valves) to exchange energy with the AC grid.

[0005] In related art, a DC direct-hung energy storage device can be grounded at both ends through a large resistor (also known as a clamping resistor) to clamp the voltage across the device to a preset voltage. However, this voltage in these devices is unstable, which can affect the reliability of the components within the device.

[0006] Summary of the Invention

[0007] In view of the above problems, the present application provides a high-voltage direct-mounted energy storage system, a control method for an energy storage device, and a control device, which can solve the problem in the related art that the voltage at both ends of the energy storage device is unstable, which affects the operating reliability of the components in the energy storage device.

[0008] In a first aspect, the present application provides a high-voltage direct-mounted energy storage system, comprising:

[0009] A clamping circuit includes a first clamping branch and a second clamping branch; an energy storage device includes a first energy storage trunk line and at least two energy storage submodules connected to the first energy storage trunk line, wherein both ends of the first energy storage trunk line are respectively connected to the clamping circuit; and at least one dielectric branch, one end of the dielectric branch is connected to the at least one energy storage submodule, and the other end is coupled to a reference ground; and further includes a first node provided on the first energy storage trunk line and a first grounding circuit connected to the first node, wherein the resistance of the first grounding circuit is less than a preset resistance threshold;

[0010] a control device for controlling each target-input energy storage submodule on both sides of a first node to be in a cut-in state based on an expected voltage of the energy storage device and measured voltages of at least two energy storage submodules connected to a first energy storage trunk line, wherein a difference between a sum of voltage amplitudes of each target-input energy storage submodule on both sides of the first node is less than a preset threshold value, and a difference between a total voltage of the energy storage device and the expected voltage is less than a preset difference.

[0011] In the implementation of this application, a high-voltage direct-mounted energy storage system may include: a clamping circuit, an energy storage device, and a control device. The energy storage device includes a first energy storage trunk line connected to the clamping circuit at both ends, at least two energy storage submodules connected to the first energy storage trunk line, at least one dielectric branch, a first node provided on the first energy storage trunk line, and a first grounding circuit connected to the first node. The resistance of the first grounding circuit is less than a preset resistance threshold, so that leakage current generated by each dielectric branch can flow back to the first energy storage trunk line in the energy storage device through the first grounding circuit and the first node, rather than through the clamping circuit. This prevents the voltage across the energy storage device from significantly offsetting, reduces the influence of the cooling water pipe's equivalent resistance to ground on the clamping effect of the clamping resistor, and thereby improves the voltage stability across the energy storage device. In addition, the control device controls each target-input energy storage submodule on both sides of the first node to be in a cut-in state based on the expected voltage of the energy storage device and the measured voltages of at least two energy storage submodules connected to the first energy storage trunk line. The difference between the sum of the voltage amplitudes of the target-input energy storage submodules on both sides of the first node is less than a preset threshold, and the difference between the total voltage of the energy storage device and the expected voltage is less than a preset difference, so that the voltage across the energy storage device can be basically stably controlled at the corresponding expected voltage. This shows that the embodiments of the present application can improve the voltage stability across the energy storage device, thereby facilitating improved operational reliability of the components in the energy storage device.

[0012] In some embodiments, the sum of the voltage amplitudes of the energy storage submodules located on each side of the first node is greater than or equal to half of the expected voltage of the energy storage device, so that the sum of the voltage amplitudes of the target input energy storage submodules located on both sides of the first node can respectively reach half of the expected voltage of the energy storage device, thereby making the total voltage of the energy storage device substantially the same as the expected voltage.

[0013] In some embodiments, the deviation percentage of the measured voltage of each energy storage submodule is less than 10%, and the number of target-connected energy storage submodules located on both sides of the first node is equal to or differs by 1. Therefore, when the switching state and / or switching position of the energy storage submodules in the energy storage device fluctuates, the difference in the sum of the voltage amplitudes of the target-connected energy storage submodules located on both sides of the first node is less than a preset threshold, and the difference between the total voltage of the energy storage device and the expected voltage is less than the preset difference. This allows the voltage across the energy storage device to be basically stably controlled at the corresponding expected voltage, without being affected by changes in the equivalent resistance to ground of the cooling water pipe, changes in the switching state and / or switching position of the energy storage submodules, etc., thereby further improving the voltage stability across the energy storage device.

[0014] In some embodiments, the first grounding circuit is a wire, or includes a grounding resistor or a grounding reactor.

[0015] In some embodiments, the preset resistance threshold is the product of the resistance value of the first clamping branch and 0.02; optionally, the preset resistance threshold is the product of the resistance value of the first clamping branch and 0.001.

[0016] In some embodiments, the first grounding circuit further includes a current detection unit, which can be used to detect current parameters on the first grounding circuit between the first node and the reference ground, so as to timely monitor whether a short circuit to ground occurs inside the energy storage device. When a short circuit to ground is detected inside the energy storage device, short-circuit protection can be performed in a timely manner, thereby facilitating further protection of the energy storage device.

[0017] In some embodiments, the energy storage device further includes at least one second energy storage trunk line and at least two energy storage submodules connected to the second energy storage trunk line, and the second energy storage trunk line is connected in parallel with the first energy storage trunk line.

[0018] In some embodiments, the energy storage device further includes a second node disposed on the second energy storage trunk line and a second grounding circuit connected to the second node. The resistance of the second grounding circuit is less than a preset resistance threshold, so that leakage current generated by each dielectric branch can flow back to the second energy storage trunk line in the energy storage device through the second grounding circuit and the second node, rather than through the clamping circuit. This prevents a significant voltage offset across the energy storage device, reduces the impact of the cooling water pipe's equivalent resistance to ground on the clamping effect of the clamping resistor, and thereby improves voltage stability across the energy storage device. Furthermore, by providing the second grounding circuit, leakage current generated by each dielectric branch connected to the energy storage submodule connected to the second energy storage trunk line can flow back to the second energy storage trunk line in the energy storage device via a shorter path, thereby reducing energy consumption of the energy storage device.

[0019] In some embodiments, the sum of the voltage amplitudes of the energy storage submodules located on each side of the second node is greater than or equal to half of the expected voltage of the energy storage device, so that the sum of the voltage amplitudes of the target input energy storage submodules located on both sides of the second node can respectively reach half of the expected voltage of the energy storage device, thereby making the total voltage of the energy storage device substantially the same as the expected voltage.

[0020] In some embodiments, the high-voltage direct-mounted energy storage system further includes a converter valve, a positive DC bus, and a negative DC bus, wherein a first end of the converter valve is connected to the positive DC bus, a second end of the converter valve is connected to the negative DC bus, a third end of the converter valve is connected to the AC power grid, and both ends of the first energy storage trunk line are respectively connected to the positive DC bus and the negative DC bus.

[0021] In some embodiments, the medium branch includes at least one of a cooling branch, a fire protection branch, and a heat medium branch.

[0022] In a second aspect, the present application provides a method for controlling an energy storage device, wherein the energy storage device is an energy storage device in a high-voltage direct-mounted energy storage system as described in any one of the first aspects above, the method comprising:

[0023] Obtaining an expected voltage of the energy storage device;

[0024] Obtaining measured voltages of at least two energy storage submodules connected to a first energy storage trunk line in the energy storage device;

[0025] Based on the expected voltage and the measured voltages of at least two energy storage submodules, each target-enabled energy storage submodule on both sides of a first node in the first energy storage trunk line is controlled to be in a cut-in state, wherein the difference between the sum of the voltage amplitudes of each target-enabled energy storage submodule on both sides of the first node is less than a preset threshold, and the difference between the total voltage of the energy storage device and the expected voltage is less than a preset difference.

[0026] In an embodiment of the present application, the expected voltage of the energy storage device and the measured voltages of at least two energy storage submodules connected to the first energy storage trunk line in the energy storage device are obtained. Furthermore, based on the expected voltage and the measured voltages of the at least two energy storage submodules, each target-input energy storage submodule on both sides of the first node in the first energy storage trunk line is controlled to be in a cut-in state, wherein the difference between the sum of the voltage amplitudes of each target-input energy storage submodule located on both sides of the first node is less than a preset threshold, and the difference between the total voltage of the energy storage device and the expected voltage is less than the preset difference, so that the voltage at both ends of the energy storage device can be basically stably controlled at the corresponding expected voltage. It can be seen that the embodiment of the present application can improve the voltage stability at both ends of the energy storage device, thereby facilitating the improvement of the operational reliability of the components in the energy storage device.

[0027] In some embodiments, controlling each target-enabled energy storage submodule on both sides of a first node in a first energy storage trunk line to be in a cut-in state based on an expected voltage and measured voltages of at least two energy storage submodules includes:

[0028] Determining, based on the expected voltage and the measured voltage of each energy storage submodule, the number of each target put-into-energy storage submodule located on a first side of the first node and the number of each target put-into-energy storage submodule located on a second side of the first node;

[0029] According to the number of target energy storage submodules located on the first side of the first node and the number of target energy storage submodules located on the second side of the first node, the target energy storage submodules on both sides of the first node in the first energy storage trunk line are controlled to be in a cut-in state.

[0030] In an embodiment of the present application, by controlling the target-to-be-connected energy storage submodules on both sides of the first node in the first energy storage trunk line to be in a switched-on state based on the determined number of target-to-be-connected energy storage submodules located on both sides of the first node, the voltage across the energy storage device can be substantially stably controlled to a corresponding expected voltage even when the switching state and / or switching position of the energy storage submodules in the energy storage device fluctuates, thereby further improving the voltage stability across the energy storage device.

[0031] In some embodiments, determining the target number of energy storage submodules to be put into operation on a first side of a first node and the target number of energy storage submodules to be put into operation on a second side of the first node based on the expected voltage and the measured voltage of each energy storage submodule includes:

[0032] When the deviation percentage of the measured voltage of each energy storage submodule is less than 10%, determining a first average voltage of each energy storage submodule according to the measured voltage of each energy storage submodule;

[0033] Determining the total number of target energy storage submodules located on both sides of the first node according to the expected voltage and the first average voltage;

[0034] Based on the total quantity, the quantity of each target put-into-energy storage submodule located on a first side of the first node and the quantity of each target put-into-energy storage submodule located on a second side of the first node are determined.

[0035] In an embodiment of the present application, by determining the number of target energy storage submodules located on the first side of the first node and the number of target energy storage submodules located on the second side of the first node according to the expected voltage and the first average voltage of each energy storage submodule in accordance with the overall voltage control sub-strategy, the number of target energy storage submodules located on the first side of the first node and the number of target energy storage submodules located on the second side of the first node can be determined more comprehensively and reasonably.

[0036] In some embodiments, determining, based on the total number, the number of target energy storage submodules to be put into operation on a first side of the first node and the number of target energy storage submodules to be put into operation on a second side of the first node includes:

[0037] If the total number is an even number, determining that the number of each target put-into-energy storage submodule located on the first side of the first node and the number of each target put-into-energy storage submodule located on the second side of the first node are both equal to one-half of the total number;

[0038] If the total number is an odd number, the number of each target put-into-energy storage submodule located on the first side of the first node and the number of each target put-into-energy storage submodule located on the second side of the first node are determined to be equal to the different values ​​of half of the difference between the total number and the preset value and half of the sum of the total number and the preset value, respectively.

[0039] In some embodiments, determining the number of target energy storage submodules to be put into operation on the first side of the first node based on the expected voltage and the measured voltage of each energy storage submodule includes:

[0040] When the deviation percentage of the measured voltages of the energy storage submodules located on the first side of the first node is less than 10%, determining a second average voltage of the energy storage submodules on the first side according to the measured voltages of the energy storage submodules located on the first side of the first node;

[0041] The number of target energy storage submodules to be put into operation on the first side of the first node is determined according to the expected voltage and the second average voltage.

[0042] In an embodiment of the present application, by determining the number of target energy storage submodules located on the first side of the first node according to the expected voltage and the measured voltage of each energy storage submodule located on the first side of the first node in accordance with the group voltage control sub-strategy, the number of target energy storage submodules located on the first side of the grounding point can be determined more flexibly and accurately.

[0043] In some embodiments, determining the number of target energy storage submodules to be put into operation on the second side of the first node based on the expected voltage and the measured voltage of each energy storage submodule includes:

[0044] When the deviation percentage of the measured voltages of the energy storage submodules located on the second side of the first node is less than 10%, determining a third average voltage of the energy storage submodules on the second side according to the measured voltages of the energy storage submodules located on the second side of the first node;

[0045] The number of target energy storage submodules to be put into operation on the second side of the first node is determined according to the expected voltage and the third average voltage.

[0046] In an embodiment of the present application, by determining the number of target energy storage submodules located on the second side of the first node according to the expected voltage and the measured voltage of each energy storage submodule located on the second side of the first node in accordance with the group voltage control sub-strategy, the number of target energy storage submodules located on the second side of the first node can be determined more flexibly and accurately.

[0047] In some embodiments, controlling each target-enabled energy storage submodule on both sides of the first node in the first energy storage trunk line to be in a cut-in state based on the number of each target-enabled energy storage submodule located on the first side of the first node and the number of each target-enabled energy storage submodule located on the second side of the first node includes:

[0048] Obtain the charge and discharge status of the energy storage device and the measured SOC of each energy storage submodule;

[0049] According to the number of target energy storage submodules located on the first side of the first node, the number of target energy storage submodules located on the second side of the first node, the charge and discharge status of the energy storage device, and the measured SOC of each energy storage submodule, the target energy storage submodules on both sides of the first node in the first energy storage trunk line are controlled to be in the cut-in state.

[0050] In the embodiment of the present application, by further considering the measured SOC of each energy storage submodule and the charge and discharge state of the energy storage device based on the number of each target-connected energy storage submodule located on the first side of the first node and the number of each target-connected energy storage submodule located on the second side of the first node, it is possible to charge and discharge the energy storage submodules located on both sides of the first node that are more in need of charging and discharging. This can not only help improve the stability of the voltage at both ends of the energy storage device, but also help improve the charge and discharge balance of each energy storage submodule of the energy storage device.

[0051] In some embodiments, controlling each target-input energy storage submodule on both sides of the first node in the first energy storage trunk line to be in a cut-in state based on the number of each target-input energy storage submodule located on the first side of the first node, the number of each target-input energy storage submodule located on the second side of the first node, the charge and discharge status of the energy storage device, and the measured SOC of each energy storage submodule includes:

[0052] When the energy storage device is in a charging state, the first n1 energy storage submodules located on the first side of the first node are respectively selected as target input submodules in ascending order of the measured SOCs of the energy storage submodules located on the first side of the first node, and each target input submodule is controlled to be in a cut-in state; wherein n1 is the number of target input energy storage submodules located on the first side of the first node;

[0053] According to the order of the measured SOC of each energy storage submodule located on the second side of the first node from low to high, the first n2 energy storage submodules located on the second side of the first node are respectively used as target input submodules, and each target input submodule is controlled to be in the cut-in state; wherein n2 is the number of each target input energy storage submodule located on the second side of the first node.

[0054] In the implementation of the present application, when the charge and discharge state of the energy storage device is the charging state, by further considering the measured SOC of each energy storage sub-module based on the number of target-input energy storage sub-modules located on both sides of the first node, multiple energy storage sub-modules with relatively low measured SOCs located on both sides of the first node can be charged as target-input energy storage sub-modules. This can not only help improve the stability of the voltage at both ends of the energy storage device, but also help improve the charging balance of each energy storage sub-module located on both sides of the first node.

[0055] In some embodiments, controlling each target-input energy storage submodule on both sides of the first node in the first energy storage trunk line to be in a cut-in state based on the number of each target-input energy storage submodule located on the first side of the first node, the number of each target-input energy storage submodule located on the second side of the first node, the charge and discharge status of the energy storage device, and the measured SOC of each energy storage submodule includes:

[0056] When the energy storage device is in a discharge state, first n1 energy storage submodules located on the first side of the first node are respectively selected as target input submodules in descending order of the measured SOCs of the energy storage submodules located on the first side of the first node, and each target input submodule is controlled to be in a cut-in state;

[0057] According to the measured SOC of each energy storage submodule located on the second side of the first node from high to low, the first n2 energy storage submodules located on the second side of the first node are determined as target input submodules, and each target input submodule is controlled to be in the cut-in state.

[0058] In the implementation of the present application, when the charge and discharge state of the energy storage device is the discharge state, by further considering the measured SOC of each energy storage sub-module based on the number of each target-input energy storage sub-module located on the second side of the first node, multiple energy storage sub-modules with relatively high measured SOC located on both sides of the first node can be used as target-input energy storage sub-modules for discharge. This can not only help improve the stability of the voltage at both ends of the energy storage device, but also help improve the charging balance of each energy storage sub-module located on both sides of the first node.

[0059] In a third aspect, the present application provides a control device for an energy storage device, wherein the energy storage device is an energy storage device in a high-voltage direct-mounted energy storage system as described in any one of the first aspects above, and the control device includes:

[0060] A first acquisition module is used to obtain an expected voltage of the energy storage device;

[0061] A second acquisition module is used to obtain the measured voltages of at least two energy storage submodules connected to the first energy storage trunk line in the energy storage device;

[0062] The control module controls each target-enabled energy storage submodule on both sides of a first node in the first energy storage trunk line to be in a cut-in state based on the expected voltage and the measured voltages of at least two energy storage submodules, wherein the difference between the sum of the voltage amplitudes of each target-enabled energy storage submodule on both sides of the first node is less than a preset threshold, and the difference between the total voltage of the energy storage device and the expected voltage is less than a preset difference.

[0063] 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, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiment below. The accompanying drawings are for illustration purposes only and are not to be considered as limiting the present application. The same reference numerals are used throughout the drawings to represent the same components. In the drawings:

[0065] FIG1 is a schematic structural diagram of a DC direct-mounted energy storage device provided by the related art;

[0066] FIG2 is a schematic diagram of the structure of the equivalent resistance to ground and the clamping resistance of the cooling water pipe in the energy storage valve cooling system provided by the related art;

[0067] FIG3 is a schematic structural diagram of a high-voltage direct-mounted energy storage system provided in some embodiments of the present application;

[0068] FIG4 is a schematic structural diagram of an energy storage submodule provided in some embodiments of the present application;

[0069] FIG5 is a schematic structural diagram of an energy storage submodule provided in other embodiments of the present application;

[0070] FIG6 is a schematic structural diagram of an energy storage submodule provided in some other embodiments of the present application;

[0071] FIG7 is a schematic structural diagram of a high-voltage direct-mounted energy storage system provided in other embodiments of the present application;

[0072] FIG8 is a schematic structural diagram of a high-voltage direct-mounted energy storage system provided in some other embodiments of the present application;

[0073] FIG9 is a schematic structural diagram of a high-voltage direct-mounted energy storage system provided in some other embodiments of the present application;

[0074] FIG10 is a schematic structural diagram of a high-voltage direct-mounted energy storage system provided in other embodiments of the present application;

[0075] FIG11 is a schematic structural diagram of a high-voltage direct-mounted energy storage system provided in other embodiments of the present application;

[0076] FIG12 is a schematic structural diagram of a high-voltage direct-mounted energy storage system provided in some other embodiments of the present application;

[0077] FIG13 is a schematic flow chart of a control method for an energy storage device according to some embodiments of the present application;

[0078] FIG14 is a flow chart of a control method for an energy storage device according to other embodiments of the present application;

[0079] FIG15 is a flow chart of a method for determining the number of target energy storage submodules located on both sides of a first node according to some embodiments of the present application;

[0080] FIG16 is a flowchart of a method for determining the number of target energy storage submodules located on the first side of a first node according to some embodiments of the present application;

[0081] FIG17 is a flowchart of a method for determining the number of target energy storage submodules located on the second side of a first node according to some embodiments of the present application;

[0082] FIG18 is a flow chart of a control method for controlling each target-enabled energy storage submodule on both sides of a first node to be in a switched-on state, provided by some embodiments of the present application;

[0083] FIG19 is a schematic structural diagram of a control device for an energy storage device provided in some embodiments of the present application. DETAILED DESCRIPTION

[0084] 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.

[0085] 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 term "include" 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.

[0086] 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 as indicating or implying relative importance or implicitly indicating the number, 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 two or more (including two), unless otherwise clearly and specifically defined.

[0087] The high-pressure direct-mounted energy storage system energy storage valve, energy storage device control method, and control device involved in the embodiments of the present application can be applied to power system energy storage technology application scenarios; of course, they can also be applied to other scenarios.

[0088] With the development of energy storage technology, DC direct-hung energy storage devices have become a common device in energy storage technology. DC direct-hung energy storage devices can exchange energy with the DC grid independently, or they can cooperate with other devices (such as converter valves) to exchange energy with the AC grid.

[0089] Figure 1 is a structural schematic diagram of a DC direct-hung energy storage device provided by the related art. As shown in Figure 1, both ends of the DC direct-hung energy storage device 11 can be grounded through a clamping resistor 12 (for example, 5MΩ) to clamp the voltage across the DC direct-hung energy storage device to a preset voltage (for example, 70kV); wherein the DC direct-hung energy storage device 11 may include multiple energy storage sub-modules (Sub-module, SM) (or simply SM1).

[0090] Typically, a DC direct-hung energy storage device includes multiple energy storage submodules (or energy storage branches). The battery cells (or battery modules) in each energy storage submodule will generate heat during operation, and an energy storage cooling system is required to remove the heat. Since the battery cells in the DC direct-hung energy storage device require a large cooling power, the energy storage cooling system may include multiple cooling subsystems (when the energy storage device is located on a valve tower, the cooling subsystem may be a cooling valve tower. The valve tower is used to support the high-voltage equipment in the energy storage device and insulate it from the ground). Each cooling subsystem is used to cool the battery cells in multiple energy storage submodules through a cooling water pipe. The location of the cooling water pipe close to the ground needs to be coupled to the ground potential to ensure the safety of the cooling source. The cooling water pipe of the cooling subsystem has a large diameter, so that the equivalent resistance of the cooling water pipe of the cooling subsystem to the ground is equivalent to the clamping resistor, which will affect the clamping effect of the clamping resistor. For example, when the cooling subsystem is in normal operation, the equivalent resistance of the cooling water pipe to the ground is about 5MΩ; when the cooling subsystem is in an alarm state, the equivalent resistance of the cooling water pipe to the ground is about 3MΩ.

[0091] FIG2 is a schematic diagram of the structure of the equivalent resistance to ground and the clamping resistor of the cooling water pipe in the energy storage cooling system provided by the related art. As shown in FIG2, since the equivalent resistance to ground Re of the cooling water pipe of the cooling subsystem is equivalent to the clamping resistor 12, there will be leakage current in the branch where each equivalent resistance to ground Re is located. The total leakage current of these leakage currents will flow to the reference ground and flow back to the DC direct-hung energy storage device through the ground branch between the two clamping resistors 12 (current is Ioo') and the clamping resistor 12 (current is I2). That is, in the case of this current flow direction, I2 is equal to the sum of I1 and Ioo', and the current Ioo' is equal to the total leakage current of the leakage current of all branches where the equivalent resistance to ground is located. In an ideal case, I1 is relatively large, the leakage current of the branch where the equivalent resistance to ground is located is small (that is, Ioo' is relatively small), and I2 can be approximately equal to I1. However, during the actual operation of the DC direct-hung energy storage device, the leakage current of each branch where the equivalent resistance to ground is located is large. Therefore, the current Ioo' is also relatively large, resulting in a large difference in the amplitude of the current I2 and the current I1, causing a large voltage offset at both ends of the DC direct-hung energy storage device, thereby causing the voltage at both ends of the DC direct-hung energy storage device to be unstable, which will affect the operational reliability of the devices in the energy storage device.

[0092] For example, when the battery cells in the energy storage submodule are at a high SOC (such as 100%), the equivalent resistance of the cooling water pipe of the cooling subsystem to the ground has the greatest impact on the clamping resistance, and the voltage of the first end of the DC direct-hung energy storage device can reach a maximum of 45.3 kV, while the voltage of the second end can reach 24.7 kV, or the voltage of the second end of the DC direct-hung energy storage device can reach a maximum of 43.9 kV, while the voltage of the first end can reach 26.1 kV.

[0093] To address the problem of unstable voltage across a DC direct-hung energy storage device in related technologies, which can affect the operational reliability of components within the energy storage device, embodiments of the present application propose providing a first grounding circuit within the energy storage device, allowing leakage current (i.e., the total leakage current of each dielectric branch) to flow back into the energy storage device through the first grounding circuit rather than through the clamping circuit (i.e., reducing current Ioo' as shown in FIG2 ). This prevents significant voltage deviation across the energy storage device, and reduces the impact of the cooling water pipe's equivalent resistance to ground on the clamping effect of the clamping resistor. Furthermore, by controlling the difference in the sum of the voltage amplitudes of the target-input energy storage submodules located on both sides of the first node to be less than a preset threshold, and by controlling the difference between the total voltage of the energy storage device and the expected voltage to be less than a preset difference, the voltage across the energy storage device can be substantially stably controlled at the corresponding expected voltage, thereby improving the stability of the voltage across the energy storage device.

[0094] In some embodiments, FIG3 is a schematic diagram of the structure of a high-voltage direct-mounted energy storage system provided in some embodiments of the present application. As shown in FIG3 , the high-voltage direct-mounted energy storage system of the embodiment of the present application may include, but is not limited to: a clamping circuit 30, an energy storage device 31, and a control device 32. Specifically, a first end of the clamping circuit 30 may be connected to a first end of the energy storage device 31, and a second end of the clamping circuit 30 may be connected to a second end of the energy storage device 31; and a control device 32 may be connected to the energy storage device 30 to control the state of each energy storage submodule in the energy storage device 31.

[0095] The clamping circuit 30 in the embodiment of the present application can be used to clamp the voltage across the energy storage device 31 to a desired voltage. The clamping circuit 30 may include, but is not limited to, a first clamping branch 301 and a second clamping branch 302. The resistance value (or clamping resistance value) of the first clamping branch 301 and the resistance value (or clamping resistance value) of the second clamping branch 302 are typically the same.

[0096] Illustratively, the first end of the first clamping branch 301 can be connected to the first end of the energy storage device 32, the second end of the first clamping branch 301 can be connected to the first end of the second clamping branch 302, and the second end of the second clamping branch 302 can be connected to the second end of the energy storage device 32, wherein the connection point of the first clamping branch 301 and the second clamping branch 302 can be coupled to the reference ground.

[0097] As another example, the first end of the first clamping branch 301 can be connected to the first end of the energy storage device 32, and the second end of the first clamping branch 301 can be coupled to the reference ground; the first end of the second clamping branch 302 can be coupled to the reference ground, and the second end of the second clamping branch 302 can be connected to the second end of the energy storage device 32.

[0098] The energy storage device 31 in the embodiment of the present application may include a first energy storage trunk line 311 and at least two energy storage sub-modules 312 connected to the first energy storage trunk line 311 .

[0099] For example, the energy storage device 31 in the embodiment of the present application may include, but is not limited to, an energy storage valve. It should be understood that when the energy storage device is an energy storage valve, the first energy storage trunk line 311 in the embodiment of the present application may be referred to as the first energy storage valve trunk line, and the energy storage submodule 312 in the embodiment of the present application may include, but is not limited to, the aforementioned SM1.

[0100] The switching state of the energy storage submodule 312 involved in the embodiment of the present application may include but is not limited to a cut-in state (or referred to as an input state) or a cut-out state. In particular, when the energy storage submodule 312 is in the cut-in state, the energy storage submodule 312 is in a state of being connected in series with the first energy storage trunk line 311; when the energy storage submodule 312 is in the cut-out state, the energy storage submodule 312 is in a bypassed state.

[0101] The first energy storage trunk line 311 in the embodiment of the present application can be connected to the clamping circuit 30 at both ends. For example, the energy storage device 31 in the embodiment of the present application can be disposed between the positive DC bus and the negative DC bus in a high-voltage direct-mounted energy storage system; of course, the energy storage device 31 can also be disposed in other locations.

[0102] When the energy storage device 31 is arranged between the positive DC bus and the negative DC bus, the two ends of the first energy storage trunk line 311 in the embodiment of the present application can be respectively connected to the positive DC bus and the negative DC bus, and the two ends of the clamping circuit 30 can be respectively connected to the positive DC bus and the negative DC bus, so that the positive and negative DC bus voltages can be clamped to a preset voltage through the clamping circuit 30.

[0103] The energy storage device 31 in the present application may further include at least one dielectric branch 313, one end of which may be connected to at least one energy storage submodule 312, and the other end of which may be coupled to a reference ground. Each dielectric branch 313 may have a corresponding equivalent resistance to ground, and the equivalent resistance to ground may be similar to or equal to the resistance of any clamping branch in the clamping circuit 30. It should be noted that, for ease of illustration, FIG3 illustrates an example of an energy storage device 31 including one dielectric branch 313; of course, the energy storage device 31 may also include multiple dielectric branches 313.

[0104] Exemplarily, the medium branch 313 may include, but is not limited to, at least one of a cooling branch, a fire protection branch, and a heat medium branch. The cooling branch may include, but is not limited to, a cooling water pipe, the fire protection branch may include, but is not limited to, a fire protection medium pipe, and the heat medium branch may include, but is not limited to, a heat medium pipe, for heating the target device in the energy storage device. For example, if the medium branch 313 includes a cooling branch, there will be an equivalent resistance to ground corresponding to the cooling water pipe. For another example, if the medium branch 313 includes a fire protection branch, there will be an equivalent resistance to ground corresponding to the fire protection medium pipe. For another example, if the medium branch 313 includes a heat medium branch, there will be an equivalent resistance to ground corresponding to the heat medium pipe.

[0105] Exemplarily, each energy storage submodule 312 may be equipped with a separate dielectric branch 313 , and a position of the dielectric branch close to the ground is coupled to the reference ground.

[0106] In another exemplary embodiment, multiple energy storage submodules 312 can share a dielectric branch 313, which is coupled to a reference ground near the ground. Multiple energy storage submodules 312 can be stacked in the energy storage device 31. In one example, the stacked arrangement forms multiple energy storage valve towers.

[0107] It should be noted that each dielectric branch 313 in the embodiment of the present application will generate leakage current, and the generated leakage current will flow through the dielectric branch 313 to the reference ground.

[0108] The energy storage device 31 in the embodiment of the present application may further include a first node GP1 disposed on the first energy storage trunk line 311 and a first grounding circuit 314 connected to the first node GP1. One end of the first grounding circuit 314 may be connected to the first node GP1, and the other end of the first grounding circuit 314 may be coupled to a reference ground. The resistance of the first grounding circuit 314 may be less than a predetermined resistance threshold, so that leakage current generated by each dielectric branch 313 (i.e., the total leakage current of each dielectric branch 313) can flow back to the first energy storage trunk line 311 in the energy storage device 31 through the first grounding circuit 314 and the first node GP1, without flowing back to the first energy storage trunk line 311 in the energy storage device 31 through the clamping circuit 30 (i.e., the current Ioo' shown in FIG. 2 can be reduced). This prevents a significant voltage offset across the energy storage device, reduces the impact of the cooling water pipe's equivalent resistance to ground on the clamping effect of the clamping resistor, and thereby improves voltage stability across the energy storage device.

[0109] For example, the resistance of the first grounding circuit in the embodiment of the present application needs to be a small resistance relative to the clamping resistor in the clamping circuit 30, so that the leakage current of the medium pipeline can flow back to the first energy storage trunk line through the first grounding circuit, while reducing the leakage current of the clamping branch (that is, the current Ioo' in Figure 2 can be reduced), wherein the resistance of the first grounding circuit can be set according to actual conditions.

[0110] For example, the preset resistance threshold in the embodiment of the present application may be the product of the resistance value of the first clamping branch (or the second clamping branch) and 0.02. For example, when the resistance value of the first clamping branch is 5MΩ, the preset resistance threshold may be 100kΩ.

[0111] Furthermore, the preset resistance threshold may be the product of the resistance value of the first clamping branch and 0.001. For example, when the resistance value of the first clamping branch is 5 MΩ, the preset resistance threshold may be 5 kΩ.

[0112] The control device 32 in the embodiment of the present application can be used to control the target input energy storage sub-modules on both sides of the first node GP1 to be in the cut-in state based on the expected voltage of the energy storage device 31 and the measured voltages of at least two energy storage sub-modules 312 connected to the first energy storage trunk line 311, wherein the difference between the sum of the voltage amplitudes of the target input energy storage sub-modules located on both sides of the first node GP1 is less than a preset threshold, and the difference between the total voltage of the energy storage device 31 and the expected voltage is less than the preset difference.

[0113] It should be understood that the total voltage of the energy storage device 31 involved in the implementation of this application is related to the voltage across the energy storage device 31. For example, the total voltage of the energy storage device 31 can be the voltage difference between the voltages across the energy storage device 31. In addition, when the energy storage device 31 is disposed between the positive DC bus and the negative DC bus, the expected voltage of the energy storage device 31 is substantially the same as the expected voltage between the positive and negative DC buses (or referred to as the expected reference voltage), and the total voltage of the energy storage device 31 is substantially the same as the voltage between the positive and negative DC buses.

[0114] Illustratively, the control device 32 in the embodiment of the present application can control each target-input energy storage sub-module located on the first side of the first node GP1 to be in the cut-in state, and each target-input energy storage sub-module located on the second side of the first node GP1 to be in the cut-in state, based on the expected voltage of the energy storage device 31 and the measured voltages of at least two energy storage sub-modules 312 connected to the first energy storage trunk line 311.

[0115] For example, in the embodiment of the present application, the difference between the sum of the voltage amplitudes of the target-input energy storage submodules located on the first side of the first node GP1 and the sum of the voltage amplitudes of the target-input energy storage submodules located on the second side of the first node GP1 is less than a preset threshold (within the electrical range that the device can withstand, such as less than the voltage amplitude of four energy storage submodules, preferably, less than the voltage amplitude of one energy storage submodule), and the difference between the total voltage of the energy storage device 31 and the expected voltage is less than a preset difference (a very small value, such as less than 10% of the expected voltage, preferably less than 5% of the expected voltage, and more preferably less than 1% of the expected voltage), so that the voltage across the energy storage device 31 can be basically stably controlled at the corresponding expected voltage. It can be seen that the embodiment of the present application can improve the voltage stability across the energy storage device 31, thereby facilitating improved operational reliability of the components in the energy storage device 31.

[0116] In a possible implementation, the deviation percentage of the measured voltage of each energy storage submodule 312 is less than 10%, and the number of target-input energy storage submodules located on both sides of the first node may be equal or differ by 1.

[0117] The deviation percentage of the measured voltage of any energy storage submodule 312 involved in the embodiments of the present application may refer to the deviation percentage between the measured voltage of the energy storage submodule 312 and a preset reference voltage; wherein the preset reference voltage may include but is not limited to any of the following: the maximum measured voltage of multiple energy storage submodules, the minimum measured voltage of multiple energy storage submodules, the average measured voltage of multiple energy storage submodules, and a preset rated voltage.

[0118] In this implementation, when the deviation percentage of the measured voltage of each energy storage submodule 312 is less than 10%, that is, when the difference between the measured voltages of different energy storage submodules 312 is not significant, the number of target-enabled energy storage submodules located on the first side of the first node can be equal to or differ by 1 from the number of target-enabled energy storage submodules located on the second side of the first node. This ensures that, when the switching status and / or switching position of the energy storage submodules in the energy storage device fluctuates, the difference in the sum of the voltage amplitudes of the target-enabled energy storage submodules located on both sides of the first node is less than a preset threshold, and the difference between the total voltage of the energy storage device and the expected voltage is less than the preset difference. This allows the voltage across the energy storage device to be substantially stably controlled at the corresponding expected voltage, regardless of changes in the equivalent resistance to ground of the cooling water pipe, changes in the switching status and / or switching position of the energy storage submodules, and so on. This not only further improves the voltage stability across the energy storage device, but also reduces the DC voltage insulation level requirements for the high-voltage equipment in the energy storage device, thereby saving the cost of the energy storage device.

[0119] In another possible implementation, the deviation percentage of the measured voltage of each energy storage submodule 312 is no less than 10%, and the difference between the number of target-to-be-activated energy storage submodules on both sides of the first node may be greater than 1 and less than a preset number threshold. The preset number threshold may include, but is not limited to, 3 or 4.

[0120] In this implementation, when the deviation percentage of the measured voltage of each energy storage submodule 312 is no less than 10%, that is, when the measured voltages of different energy storage submodules 312 differ significantly, the difference between the number of target-enabled energy storage submodules on the first side of the first node and the number of target-enabled energy storage submodules on the second side of the first node can be greater than 1 and less than a preset threshold value. This ensures that, when the switching status and / or switching position of the energy storage submodules in the energy storage device fluctuate, the difference in the sum of the voltage amplitudes of the target-enabled energy storage submodules on both sides of the first node is less than the preset threshold value, and the difference between the total voltage of the energy storage device and the expected voltage is less than the preset difference. This allows the voltage across the energy storage device to be substantially stably controlled at the corresponding expected voltage, regardless of changes in the cooling water pipe's equivalent resistance to ground, changes in the switching status and / or switching position of the energy storage submodules, and so on. This not only further improves the voltage stability across the energy storage device, but also reduces the DC voltage insulation level requirements for high-voltage equipment in the energy storage device, thereby reducing the cost of the energy storage device.

[0121] For example, assuming that the measured voltage of each energy storage sub-module located on the first side of the first node is larger, but the measured voltage of each energy storage sub-module located on the second side of the first node is smaller, the control device can determine that the number of each target-put-input energy storage sub-module located on the first side of the first node can be smaller, and the number of each target-put-input energy storage sub-module located on the second side of the first node can be larger, but the difference between the two numbers can be less than the preset number threshold.

[0122] In summary, the high-voltage direct-mounted energy storage system in the embodiment of the present application may include: a clamping circuit, an energy storage device, and a control device. The energy storage device includes a first energy storage trunk line connected to the clamping circuit at both ends, at least two energy storage submodules connected to the first energy storage trunk line, at least one dielectric branch, a first node provided on the first energy storage trunk line, and a first grounding circuit connected to the first node. The resistance of the first grounding circuit is less than a preset resistance threshold, so that the leakage current generated by each dielectric branch can flow back to the first energy storage trunk line in the energy storage device through the first grounding circuit and the first node, rather than through the clamping circuit (i.e., the current Ioo' in FIG. 2 can be reduced), so that the voltage across the energy storage device does not deviate significantly, and the influence of the equivalent resistance of the cooling water pipe to ground on the clamping effect of the clamping resistor can be reduced, thereby facilitating the improvement of the voltage stability across the energy storage device. In addition, the control device controls each target-input energy storage submodule on both sides of the first node to be in a cut-in state based on the expected voltage of the energy storage device and the measured voltages of at least two energy storage submodules connected to the first energy storage trunk line. The difference between the sum of the voltage amplitudes of the target-input energy storage submodules on both sides of the first node is less than a preset threshold, and the difference between the total voltage of the energy storage device and the expected voltage is less than a preset difference, so that the voltage across the energy storage device can be basically stably controlled at the corresponding expected voltage. This shows that the embodiments of the present application can improve the voltage stability across the energy storage device, thereby facilitating improved operational reliability of the components in the energy storage device.

[0123] In some embodiments, the embodiments of the present application provide an exemplary introduction and description of the relevant contents regarding the position setting of the first node in the first energy storage trunk line.

[0124] In a possible implementation, the sum of the voltage amplitudes of the energy storage submodules 312 located on each side of the first node GP1 is greater than or equal to half of the expected voltage of the energy storage device.

[0125] In this implementation, the sum of the voltage amplitudes of the energy storage submodules located on the first side of the first node is greater than or equal to one-half of the expected voltage of the energy storage device, and the sum of the voltage amplitudes of the energy storage submodules located on the second side of the first node is greater than or equal to one-half of the expected voltage of the energy storage device. This allows the sum of the voltage amplitudes of the target-input energy storage submodules located on both sides of the first node to each reach one-half of the expected voltage of the energy storage device, thereby ensuring that the total voltage of the energy storage device is substantially the same as the expected voltage.

[0126] In another possible implementation, the sum of the voltage amplitudes of the energy storage submodules located on either side of the first node is less than half the expected voltage of the energy storage device, and the difference between half the expected voltage of the energy storage device and the sum of the voltage amplitudes of the energy storage submodules located on either side of the first node can be less than a preset voltage difference. This allows the sum of the voltage amplitudes of the target-input energy storage submodules located on both sides of the first node to substantially reach half the expected voltage of the energy storage device, thereby ensuring that the difference between the total voltage of the energy storage device and the expected voltage is less than the preset difference. Exemplarily, the preset voltage difference can be half the preset difference.

[0127] For example, in an embodiment of the present application, the number of energy storage sub-modules located on the first side of the first node GP2 may be equal to the number of energy storage sub-modules located on the second side of the first node GP1, or the difference between the number of energy storage sub-modules located on the first side of the first node GP2 and the number of energy storage sub-modules located on the second side of the first node GP1 may be less than a preset number threshold.

[0128] For ease of understanding, the following embodiments of the present application provide exemplary descriptions of the relevant contents of the energy storage submodule 312 .

[0129] FIG4 is a schematic diagram of the structure of the energy storage submodule provided in some embodiments of the present application. As shown in FIG4 , the energy storage submodule 312 in the embodiment of the present application may include, but is not limited to: a bypass unit 312A, a power unit 312B, a battery startup circuit unit 312C, and a battery unit 312D. Specifically, the bypass unit 312A may be used to switch the bypass state of the energy storage submodule 31; the power unit 312B may be used to switch the on / off state of the energy storage submodule; the battery startup circuit unit 312C may be used to limit the charge and discharge current during the startup phase of charging and discharging the battery unit 312D; and the battery unit 312D may be used to store or release electrical energy based on the on / off state of the energy storage submodule and the voltage across the energy storage device.

[0130] Exemplarily, the power unit 312B may include but is not limited to a bridge circuit unit, a voltage-grading capacitor and / or a voltage-grading resistor, wherein the bridge circuit unit may include but is not limited to a half-bridge circuit unit or a full-bridge circuit unit.

[0131] FIG5 is a schematic diagram of the structure of the energy storage submodule provided in some other embodiments of the present application. As shown in FIG5 , the energy storage submodule 31 may include but is not limited to: a bypass unit 312A, a power unit 312B, a battery start-up circuit unit 312C and a battery unit 312D. Among them, the bypass unit 312A may include but is not limited to a bypass switch K3. The power unit 312B may include but is not limited to a half-bridge circuit unit BC0, a voltage-equalizing capacitor C0 and / or a voltage-equalizing resistor R0; the half-bridge circuit unit BC0 may include but is not limited to a switch tube T1 and a switch tube T2, and a diode D1 and a diode D2 connected in parallel with each switch tube respectively. The battery start-up circuit unit 312C may include but is not limited to a pre-charge unit and a direct-charge unit connected in parallel; wherein the pre-charge unit may include a switch K2 and a resistor R1 connected in series; the direct-charge unit may include a switch K1.

[0132] FIG6 is a schematic structural diagram of an energy storage submodule provided in some other embodiments of the present application. As shown in FIG6 , the energy storage submodule 31 may include but is not limited to: a bypass unit 312A, a power unit 312B, a battery start-up circuit unit 312C, and a battery unit 312D. The bypass unit 312A may include but is not limited to a bypass switch K3. The power unit 312B may include but is not limited to a full-bridge circuit unit BC1, a voltage-equalizing capacitor C0, and / or a voltage-equalizing resistor R0; the full-bridge circuit unit BC1 may include but is not limited to switch tubes T1 to T4, and diodes D1 to D4 connected in parallel with each switch tube, respectively. The battery start-up circuit unit 312C may include but is not limited to a pre-charge unit and a direct-charge unit connected in parallel; the pre-charge unit may include a switch K2 and a resistor R1 connected in series; the direct-charge unit may include a switch K1.

[0133] Of course, the energy storage submodule 312 may also adopt other forms of structure. It should be noted that the structure of the energy storage submodule 312 is not limited in the embodiment of the present application. As long as the switching state of the energy storage submodule can be switched, the energy storage device of the embodiment of the present application can be applied.

[0134] In some embodiments, based on the above embodiments, the embodiments of the present application provide an exemplary description of the relevant contents of the above-mentioned first grounding circuit 314 .

[0135] In one possible implementation, the first grounding circuit 314 may include a grounding resistor or a grounding reactor to limit the current flowing through the first grounding circuit 314 , thereby improving voltage stability across the energy storage device and protecting the energy storage device. It should be noted that the resistance of the grounding resistor or grounding reactor may be less than a preset resistance threshold.

[0136] It should be noted that, for the sake of convenience, the following embodiments of the present application are illustrated by taking the above-mentioned energy storage device 31 as being arranged between the positive DC bus and the negative DC bus, and the bridge circuit unit in the above-mentioned power unit 312B as a half-bridge circuit unit as an example.

[0137] FIG7 is a schematic structural diagram of a high-voltage, direct-mounted energy storage system according to another embodiment of the present application. As shown in FIG7 , the energy storage device according to the embodiment of the present application may include: a first grounding circuit 314 and N energy storage submodules 312 connected to a first energy storage trunk line 311. For example, one end of the first energy storage trunk line 311 may be connected to a positive DC bus via a current-limiting reactor XL1, and the other end of the first energy storage trunk line 311 may be connected to a negative DC bus.

[0138] Exemplarily, the two ends of the clamping circuit 30 can be connected to the positive DC bus and the negative DC bus respectively, and the clamping circuit 30 can include a first clamping branch 301 and a second clamping branch 302, and the connection point of the first clamping branch 301 and the second clamping branch 302 can be coupled to the reference ground; wherein, the first clamping branch 301 and the second clamping branch 302 can respectively include corresponding clamping resistors.

[0139] One end of the first grounding circuit 314 may be connected to the first node GP1 in the first energy storage trunk line 311 , and the other end of the first grounding circuit 314 may be coupled to the reference ground; the first grounding circuit 314 may include a grounding resistor Rg.

[0140] FIG8 is a structural diagram of a high-voltage direct-mounted energy storage system provided in some other embodiments of the present application. As shown in FIG8 , compared with the high-voltage direct-mounted energy storage system shown in FIG7 , the first grounding circuit 314 in FIG8 may include a grounding reactor XL2.

[0141] It should be understood that Figures 7 and 8 illustrate the example of the first node GP1 being located at the center of the first energy storage trunk line 311, that is, the number N / 2 of each energy storage sub-module located on the first side of the first node GP1 of the first energy storage trunk line 311 is equal to the number N / 2 of each energy storage sub-module located on the second side of the first node GP1 of the first energy storage trunk line 311, where N represents the total number of all energy storage sub-modules connected to the first energy storage trunk line 311 in the energy storage device.

[0142] In another possible implementation, the first grounding circuit 314 may be a wire (or referred to as a resistance-free grounding circuit).

[0143] Figure 9 is a structural schematic diagram of a high-voltage direct-mounted energy storage system provided in some other embodiments of the present application. As shown in Figure 9, compared with the high-voltage direct-mounted energy storage system shown in Figure 7, the first grounding circuit 314 in Figure 9 is a wire, that is, the first node GP1 is coupled to the reference ground through a wire.

[0144] Of course, the first grounding circuit 314 in the embodiment of the present application may also adopt other circuit forms.

[0145] In some embodiments, the first grounding circuit 314 in the embodiments of the present application may further include a current detection unit, which may be used to detect current parameters on the first grounding circuit 314 between the first node and the reference ground, so as to timely monitor whether a short circuit to ground occurs inside the energy storage device. In the event that a short circuit to ground is detected inside the energy storage device, short-circuit protection may be performed in a timely manner, thereby facilitating further protection of the energy storage device.

[0146] In some embodiments, Figure 10 is a structural schematic diagram of a high-voltage direct-mounted energy storage system provided in other embodiments of the present application. Considering that the energy storage capacity of the energy storage device in the high-voltage direct-mounted energy storage system is getting larger and larger, as shown in Figure 10, the energy storage device 31 in the embodiment of the present application can also include at least one second energy storage trunk line 315 and at least two energy storage sub-modules 312 connected to the second energy storage trunk line 315, wherein the second energy storage trunk line 315 can be connected in parallel with the first energy storage trunk line 311.

[0147] When the energy storage device 31 is arranged between the positive DC bus and the negative DC bus, the two ends of the second energy storage trunk line 315 in the embodiment of the present application can be connected to the positive DC bus and the negative DC bus respectively.

[0148] In some embodiments, the energy storage device in the embodiments of the present application may further include at least one dielectric branch 313 connected to the above-mentioned energy storage sub-module 312; wherein, one end of the dielectric branch 313 can be connected to at least one of the above-mentioned energy storage sub-modules 312, and the other end of the dielectric branch 313 can be coupled to the reference ground, so that the leakage current generated by the dielectric branch 313 will flow through the dielectric branch 313 to the reference ground.

[0149] In some embodiments, leakage current generated by each dielectric branch 313 connected to the energy storage submodule 312 connected to the second energy storage trunk line 315 can flow back to the second energy storage trunk line 315 in the energy storage device 31 through the first grounding circuit 314 and the first node GP1, without flowing back to the second energy storage trunk line 315 in the energy storage device 31 through the clamping circuit 30 (i.e., the current Ioo' in Figure 2 can be reduced), so that the voltage across the energy storage device does not undergo a large offset, and the influence of the equivalent resistance to ground of the cooling water pipe on the clamping effect of the clamping resistor can be reduced, thereby facilitating the improvement of the voltage stability across the energy storage device.

[0150] In some embodiments, the energy storage device 31 in the embodiments of the present application may further include a second node GP2 disposed on the second energy storage trunk line 315 and a second ground circuit 316 connected to the second node GP2. One end of the second ground circuit 316 may be connected to the second node GP2, and the other end of the second ground circuit 316 may be coupled to a reference ground. The resistance of the second ground circuit 316 may be less than a preset resistance threshold, so that leakage current generated by each dielectric branch 313 can flow back to the second energy storage trunk line 315 in the energy storage device 31 through the second ground circuit 316 and the second node GP2, rather than through the clamping circuit 30 (i.e., the current Ioo' shown in FIG. 2 can be reduced). This prevents a significant voltage offset across the energy storage device, reduces the effect of the cooling water pipe's equivalent resistance to ground on the clamping effect of the clamping resistor, and thereby improves voltage stability across the energy storage device. In addition, by setting up a second grounding circuit 316, the leakage current generated by each dielectric branch 313 connected to the energy storage sub-module 312 connected to the second energy storage trunk line 315 can flow back to the second energy storage trunk line 315 in the energy storage device 31 through a shorter path, which is beneficial to reducing the energy consumption of the energy storage device 31.

[0151] In some embodiments, the sum of the voltage amplitudes of the energy storage submodules 312 located on each side of the second node GP2 is greater than or equal to half of the expected voltage of the energy storage device.

[0152] In this implementation, the sum of the voltage amplitudes of the energy storage submodules located on the first side of the second node GP2 is greater than or equal to half the expected voltage of the energy storage device, and the sum of the voltage amplitudes of the energy storage submodules located on the second side of the second node GP2 is greater than or equal to half the expected voltage of the energy storage device. This allows the sum of the voltage amplitudes of the target input energy storage submodules located on both sides of the second node GP2 to each reach half the expected voltage of the energy storage device, thereby ensuring that the total voltage of the energy storage device is substantially the same as the expected voltage.

[0153] In another possible implementation, the sum of the voltage amplitudes of the energy storage submodules located on either side of the second node GP2 is less than half the expected voltage of the energy storage device, and the difference between half the expected voltage of the energy storage device and the sum of the voltage amplitudes of the energy storage submodules located on either side of the second node GP2 is less than a preset voltage difference. This allows the sum of the voltage amplitudes of the target-input energy storage submodules located on both sides of the second node to substantially reach half the expected voltage of the energy storage device, thereby ensuring that the difference between the total voltage of the energy storage device and the expected voltage is less than the preset difference. Exemplarily, the preset voltage difference may be half the preset difference.

[0154] For example, in an embodiment of the present application, the number of energy storage sub-modules located on the first side of the second node GP2 may be equal to the number of energy storage sub-modules located on the second side of the second node GP2, or the difference between the number of energy storage sub-modules located on the first side of the second node GP2 and the number of energy storage sub-modules located on the second side of the second node GP2 may be less than a preset number threshold.

[0155] In some embodiments, FIG11 is a schematic structural diagram of a high-voltage direct-mounted energy storage system provided in other embodiments of the present application. Based on the above embodiments, considering that the energy storage device can cooperate with the converter valve to exchange energy with the AC power grid, as shown in FIG11, the high-voltage direct-mounted energy storage system of the embodiment of the present application can also include a converter valve 33, a positive DC bus 34, and a negative DC bus 35. The first end of the converter valve 33 can be connected to the positive DC bus 34, the second end of the converter valve 33 can be connected to the negative DC bus 35, and the third end of the converter valve 33 can be connected to the AC power grid. The first energy storage trunk line 311 in the energy storage device 31 can be connected to the positive DC bus 34 and the negative DC bus 35 at both ends, that is, the energy storage device 31 can be connected to the AC power grid through the converter valve 33, so that the energy storage device 31 can cooperate with the converter valve 33 to achieve the storage and release of electrical energy. The converter valve 33 can exchange energy with the AC power grid and can be used to control input power and output power.

[0156] In some embodiments, FIG12 is a schematic diagram of the structure of a high-voltage direct-mounted energy storage system provided in other embodiments of the present application. Based on the above embodiments, the present application provides an exemplary introduction to the relevant contents of the converter valve 33. As shown in FIG12, the converter valve 33 may include multiple converter trunk lines 331 and at least two converter submodules 332 (or simply SM2) connected to the converter trunk lines 331. The two ends of each converter trunk line 331 can be connected to the positive and negative DC busbars via corresponding current-limiting reactors XL3, and the third node GP3 of each converter trunk line 331 can be connected to the AC power grid.

[0157] Of course, the converter valve 33 in the embodiment of the present application may also adopt other circuit forms, as long as it can realize energy exchange with the AC power grid and control the input power and output power functions.

[0158] In some embodiments, FIG13 is a flow chart of a control method for an energy storage device provided in some embodiments of the present application. The energy storage device in the embodiments of the present application can be the energy storage device in any of the above-mentioned high-voltage direct-mounted energy storage system embodiments of the present application. Based on the above-mentioned embodiments, the embodiments of the present application take the application of this method to the control device of the above-mentioned energy storage device as an example to provide an exemplary introduction to the relevant contents of the control method of the above-mentioned energy storage device. As shown in FIG13, the method of the embodiments of the present application may include the following steps:

[0159] Step S1301: Obtain the expected voltage of the energy storage device.

[0160] In a possible implementation, the control device may receive an expected voltage of the energy storage device sent by other equipment.

[0161] In another possible implementation, the control device may receive an expected voltage of the energy storage device input by a user.

[0162] In another possible implementation, the control device may obtain the expected voltage of the energy storage device from a preset data storage location; wherein the preset data storage location may include but is not limited to a distributed database or a local storage location of the control device.

[0163] Of course, the control device can also obtain the expected voltage of the energy storage device through other methods.

[0164] Step S1302: Obtain the measured voltages of at least two energy storage submodules connected to a first energy storage trunk line in the energy storage device.

[0165] In this step, the control device may obtain the measured voltage of each energy storage submodule connected to the first energy storage trunk line in the energy storage device.

[0166] For example, the measured voltage of the energy storage submodule involved in the embodiments of the present application may include but is not limited to the voltage of the grading capacitor or the grading resistor in the energy storage submodule.

[0167] It should be understood that the energy storage device may be provided with a voltage detection unit for detecting the measured voltage of each energy storage submodule.

[0168] Step S1303: Based on the expected voltage and the measured voltages of at least two energy storage submodules, control the target-input energy storage submodules on both sides of the first node in the first energy storage trunk line to be in a cut-in state, wherein the difference between the sum of the voltage amplitudes of the target-input energy storage submodules on both sides of the first node is less than a preset threshold, and the difference between the total voltage of the energy storage device and the expected voltage is less than a preset difference.

[0169] In this step, the control device can control each target input energy storage submodule located on the first side of the first node to be in the cut-in state, and each target input energy storage submodule located on the second side of the first node to be in the cut-in state according to the expected voltage and the measured voltage of at least two energy storage submodules.

[0170] Illustratively, in an embodiment of the present application, the difference between the sum of the voltage amplitudes of the target-input energy storage submodules located on the first side of the first node and the sum of the voltage amplitudes of the target-input energy storage submodules located on the second side of the first node is less than a preset threshold, and the difference between the total voltage of the energy storage device and the expected voltage is less than a preset difference (a very small value), so that the voltage across the energy storage device can be basically stably controlled at the corresponding expected voltage.

[0171] In one possible implementation, the control device may control each target-input energy storage submodule located on a first side of a first node to be in a cut-in state, and each target-input energy storage submodule located on a second side of the first node to be in a cut-in state, according to a preset switching control strategy based on the expected voltage and the measured voltages of at least two energy storage submodules, so that the difference between the sum of the voltage amplitudes of the target-input energy storage submodules located on both sides of the first node is less than a preset threshold, and the difference between the total voltage of the energy storage device and the expected voltage is less than a preset difference.

[0172] Exemplarily, the preset switching control strategy can be used to indicate the determination of the number of target energy storage sub-modules on both sides of the first node in the first energy storage trunk line, and control the target energy storage sub-modules on both sides of the first node to be in the switched-on state according to the number of target energy storage sub-modules on both sides of the first node.

[0173] In another possible implementation, the control device may input the expected voltage and the measured voltages of at least two energy storage submodules into a preset switching control model to obtain identification information of each target-input energy storage submodule on both sides of the first node output by the preset switching control model. Based on the identification information of each target-input energy storage submodule on both sides of the first node, the control device may control each target-input energy storage submodule on both sides of the first node to be in a switched-on state, such that the difference between the sum of the voltage amplitudes of each target-input energy storage submodule on both sides of the first node is less than a preset threshold, and the difference between the total voltage of the energy storage device and the expected voltage is less than a preset difference. Exemplarily, the preset switching control model may include, but is not limited to, a machine learning model.

[0174] Of course, the control device can also control the target energy storage submodules on both sides of the first node in the first energy storage trunk line to be in the cut-in state in other ways according to the expected voltage and the measured voltages of at least two energy storage submodules.

[0175] In summary, in the embodiments of the present application, the expected voltage of the energy storage device and the measured voltages of at least two energy storage submodules connected to the first energy storage trunk line in the energy storage device are obtained. Furthermore, based on the expected voltage and the measured voltages of the at least two energy storage submodules, each target-input energy storage submodule on both sides of the first node in the first energy storage trunk line is controlled to be in a cut-in state, wherein the difference between the sum of the voltage amplitudes of each target-input energy storage submodule on both sides of the first node is less than a preset threshold, and the difference between the total voltage of the energy storage device and the expected voltage is less than the preset difference, so that the voltage at both ends of the energy storage device can be basically stably controlled at the corresponding expected voltage. It can be seen that the embodiments of the present application can improve the voltage stability at both ends of the energy storage device, thereby facilitating the improvement of the operational reliability of the components in the energy storage device.

[0176] It should be noted that, when the energy storage device further includes a second node provided in the second energy storage trunk line and a second grounding circuit connected to the second node, the control device may further control each target-input energy storage submodule on both sides of the second node in the second energy storage trunk line to be in a cut-in state according to the expected voltage and the measured voltages of at least two energy storage submodules in the second energy storage trunk line. The specific control method may refer to the relevant content of the above-mentioned step S103 and will not be repeated here.

[0177] In some embodiments, FIG14 is a flow chart of a control method for an energy storage device provided in another embodiment of the present application. Based on the above embodiment, the present embodiment provides an exemplary introduction to the relevant contents of the above step S1303. As shown in FIG14, step S1303 in the embodiment of the present application may include the following steps:

[0178] Step S1303A: Determine the number of target energy storage submodules on the first side of the first node and the number of target energy storage submodules on the second side of the first node based on the expected voltage and the measured voltage of each energy storage submodule.

[0179] In this step, the control device can determine the number of target energy storage submodules (i.e., energy storage submodules that need to be in the cut-in state) located on the first side of the first node and the number of target energy storage submodules located on the second side of the first node according to the expected voltage and the measured voltage of each energy storage submodule in accordance with the preset voltage control strategy; wherein the preset voltage control strategy may include but is not limited to an overall voltage control substratum or a group voltage control substratum.

[0180] Exemplarily, the overall voltage control sub-strategy is used to indicate that the number of target energy storage sub-modules to be put into operation on both sides of the first node in the energy storage device is determined by treating the energy storage sub-modules on both sides of the first node as a whole based on the measured voltages of the energy storage sub-modules in the energy storage device.

[0181] Exemplarily, the group voltage control sub-strategy is used to indicate the determination of the target energy storage sub-modules to be put into operation on the first side of the first node based on the measured voltage of each energy storage sub-module located on the first side of the first node in the energy storage device, and the determination of the number of target energy storage sub-modules to be put into operation on the second side of the first node based on the measured voltage of each energy storage sub-module located on the second side of the first node in the energy storage device.

[0182] Of course, the control device can also determine the number of target energy storage submodules to be put into operation on the first side of the first node and the number of target energy storage submodules to be put into operation on the second side of the first node in other ways based on the expected voltage and the measured voltage of each energy storage submodule.

[0183] Step S1303B: Control the target energy storage submodules on both sides of the first node in the first energy storage trunk line to be in a cut-in state according to the number of the target energy storage submodules located on the first side of the first node and the number of the target energy storage submodules located on the second side of the first node.

[0184] In this step, the control device can control the target energy storage submodules located on the first side of the first node in the first energy storage trunk line to be in the cut-in state according to the number of the target energy storage submodules located on the first side of the first node, and control the target energy storage submodules located on the second side of the first node in the first energy storage trunk line to be in the cut-in state according to the number of the target energy storage submodules located on the second side of the first node, so that the difference between the sum of the voltage amplitudes of the target energy storage submodules located on both sides of the first node is less than a preset threshold, and the difference between the total voltage of the energy storage device and the expected voltage is less than the preset difference, so that when the switching state and / or switching position of the energy storage submodules in the energy storage device fluctuates, the voltage across the energy storage device can be basically stably controlled at the corresponding expected voltage, thereby facilitating further improving the voltage stability across the energy storage device.

[0185] Exemplarily, when the deviation percentage of the measured voltage of each energy storage submodule is less than 10%, the number of target-connected energy storage submodules located on both sides of the first node can be equal or differ by 1, so that when the switching state and / or switching position of the energy storage submodules in the energy storage device fluctuates, the difference in the sum of the voltage amplitudes of the target-connected energy storage submodules located on both sides of the first node is less than a preset threshold, and the difference between the total voltage of the energy storage device and the expected voltage is less than the preset difference. So that when the switching state and / or switching position of the energy storage submodules in the energy storage device fluctuates, the voltage across the energy storage device can be basically stably controlled at the corresponding expected voltage, and is not affected by changes in the equivalent resistance to ground of the cooling water pipe, changes in the switching state and / or switching position of the energy storage submodules, etc., thereby facilitating further improving the voltage stability across the energy storage device.

[0186] In another exemplary embodiment, the deviation percentage of the measured voltage of each energy storage submodule 312 is no less than 10%, and the difference between the number of target-connected energy storage submodules on both sides of the first node can be greater than 1 and less than a preset number threshold. This allows, when the switching state and / or switching position of the energy storage submodules in the energy storage device fluctuates, the difference in the sum of the voltage amplitudes of the target-connected energy storage submodules on both sides of the first node is less than the preset threshold, and the difference between the total voltage of the energy storage device and the expected voltage is less than the preset difference. This allows the voltage across the energy storage device to be substantially stably controlled at the corresponding expected voltage, regardless of changes in the equivalent resistance to ground of the cooling water pipe, changes in the switching state and / or switching position of the energy storage submodules, and so on. This not only further improves the voltage stability across the energy storage device, but also reduces the DC voltage insulation level requirements of the high-voltage equipment in the energy storage device to ground, thereby saving the cost of the energy storage device.

[0187] In summary, in the embodiments of the present application, the number of target energy storage submodules to be put into operation on the first side of the first node and the number of target energy storage submodules to be put into operation on the second side of the first node are determined based on the expected voltage and the measured voltage of each energy storage submodule. Furthermore, based on the number of target energy storage submodules to be put into operation on the first side of the first node and the number of target energy storage submodules to be put into operation on the second side of the first node, the target energy storage submodules to be put into operation on both sides of the first node in the first energy storage trunk line are controlled to be in the switched-on state, so that the difference between the sum of the voltage amplitudes of the target energy storage submodules to be put into operation on both sides of the first node is less than a preset threshold, and the difference between the total voltage of the energy storage device and the expected voltage is less than a preset difference. It can be seen that in the embodiment of the present application, by controlling the switching-on state of each target-connected energy storage submodule on both sides of the first node in the first energy storage trunk line according to the number of each target-connected energy storage submodule located on both sides of the first node, the voltage across the energy storage device can be basically stably controlled to a corresponding expected voltage even when the switching state and / or switching position of the energy storage submodules in the energy storage device fluctuates, thereby facilitating further improving the voltage stability across the energy storage device.

[0188] In some embodiments, FIG15 is a flow chart of a method for determining the number of target energy storage submodules located on both sides of a first node provided by some embodiments of the present application. Based on the above embodiments, the present application introduces a possible implementation method of the above step S1303A of "determining the number of target energy storage submodules located on the first side of the first node and the number of target energy storage submodules located on the second side of the first node based on the expected voltage and the measured voltage of each energy storage submodule." As shown in FIG15, the above step S1303A may include the following steps:

[0189] Step S1501 : when the deviation percentage of the actually measured voltage of each energy storage submodule is less than 10%, determine the first average voltage of each energy storage submodule according to the actually measured voltage of each energy storage submodule.

[0190] In this step, when the deviation percentage of the measured voltage of each energy storage submodule is less than 10%, the control device can determine the first average voltage of each energy storage submodule according to the measured voltage of each energy storage submodule and the overall voltage control sub-strategy.

[0191] Exemplarily, the control device may determine the first average voltage of each energy storage submodule according to the measured voltage of each energy storage submodule by referring to the following formula (1).

[0192] Wherein, Uci represents the measured voltage of the i-th energy storage submodule in the energy storage device, and Uc-avg1 represents the first average voltage.

[0193] Of course, the control device may determine the first average voltage of each energy storage submodule based on the measured voltage of each energy storage submodule or by referring to other modified formulas or equivalent formulas of the above formula (1).

[0194] Step S1502: Determine the total number of target energy storage submodules located on both sides of the first node according to the expected voltage and the first average voltage.

[0195] In this step, the control device may determine the total number of target-input energy storage submodules located on both sides of the first node according to the expected voltage and the first average voltage and in accordance with the overall voltage control sub-strategy.

[0196] Exemplarily, the control device may determine the total number of target-input energy storage submodules located on both sides of the first node according to the expected voltage and the first average voltage with reference to the following formula (2).

[0197] Where n represents the total number and Uref represents the expected voltage of the energy storage device.

[0198] It should be noted that, when the expected voltage and the first average voltage cannot be divided evenly, the total number can be determined by rounding off to an integer.

[0199] Of course, the control device may determine the total quantity based on the expected voltage and the first average voltage, or by referring to other modified formulas or equivalent formulas of the above formula (2).

[0200] Step S1503: Based on the total quantity, determine the quantity of each target put-into-energy storage submodule located on the first side of the first node and the quantity of each target put-into-energy storage submodule located on the second side of the first node.

[0201] In this step, the control device can determine the number of each target put-into energy storage submodule located on the first side of the first node and the number of each target put-into energy storage submodule located on the second side of the first node based on the total number and in accordance with the overall voltage control sub-strategy.

[0202] In one possible implementation, if the total number is an even number, the number of target energy storage submodules located on the first side of the first node and the number of target energy storage submodules located on the second side of the first node are both equal to half of the total number.

[0203] In this implementation, when the total number is an even number, the control device may use half of the total number as the number of target energy storage submodules located on the first side of the first node and the number of target energy storage submodules located on the second side of the first node.

[0204] It can be seen that in this implementation, the number of target-connected energy storage submodules located on the first side of the first node can be made the same as the number of target-connected energy storage submodules located on the second side of the first node. This allows the voltage across the energy storage device to be basically stably controlled at the corresponding expected voltage when the switching state and / or switching position of the energy storage submodules in the energy storage device fluctuates, thereby facilitating further improving the voltage stability across the energy storage device.

[0205] In another possible implementation, if the total number is an odd number, the number of each target put-in-power energy storage submodule located on the first side of the first node and the number of each target put-in-power energy storage submodule located on the second side of the first node are determined to be equal to the different values ​​of half of the difference between the total number and the preset value and half of the sum of the total number and the preset value, respectively.

[0206] For example, the preset value in the embodiment of the present application may be an odd number. For example, the preset value may include but is not limited to 1.

[0207] In this implementation, when the total number n is an odd number, the control device may use half of the difference between the total number n and the preset value n0 as the target number of each energy storage submodule to be put into operation on the first side of the first node, and use half of the sum of the total number n and the preset value n0 as the target number of each energy storage submodule to be put into operation on the second side of the first node. Alternatively, the control device may use half of the difference between the total number n and the preset value n0 as the target number of each energy storage submodule to be put into operation on the second side of the first node, and use half of the sum of the total number n and the preset value n0 as the target number of each energy storage submodule to be put into operation on the first side of the first node.

[0208] It should be noted that in order to charge and discharge the energy storage sub-modules located on both sides of the first node that need charging and discharging more, in an embodiment of the present application, the control device can further determine the number of target energy storage sub-modules located on the first side of the first node and the number of target energy storage sub-modules located on the second side of the first node based on the SOC of each energy storage sub-module located on the first side of the first node and the SOC of each energy storage sub-module located on the second side of the first node.

[0209] Exemplarily, when the charge and discharge state of the energy storage device is a charging state, the control device may obtain a first sequence by sorting the energy storage sub-modules located on the first side of the first node in ascending order of SOC, and obtain a second sequence by sorting the energy storage sub-modules located on the second side of the first node in ascending order of SOC.

[0210] Further, if the SOC of the (n-n0) / 2+1th energy storage submodule in the first sequence is less than the SOC of the (n-n0) / 2+1th energy storage submodule in the second sequence, the control device may use half of the sum of the total number n and the preset value n0 as the target number of each energy storage submodule to be put into operation on the first side of the first node, and use half of the difference between the total number n and the preset value n0 as the target number of each energy storage submodule to be put into operation on the second side of the first node. If the SOC of the (n-n0) / 2+1th energy storage submodule in the first sequence is greater than the SOC of the (n-n0) / 2+1th energy storage submodule in the second sequence, the control device may use half of the sum of the total number n and the preset value n0 as the target number of each energy storage submodule to be put into operation on the second side of the first node, and use half of the difference between the total number n and the preset value n0 as the target number of each energy storage submodule to be put into operation on the first side of the first node.

[0211] As another example, when the charge and discharge state of the energy storage device is a discharge state, the control device may obtain a third sequence by sorting the energy storage sub-modules located on the first side of the first node in descending order of SOC, and obtain a fourth sequence by sorting the energy storage sub-modules located on the second side of the first node in descending order of SOC.

[0212] Furthermore, if the SOC of the (n-n0) / 2+1th energy storage submodule in the third sequence is greater than the SOC of the (n-n0) / 2+1th energy storage submodule in the fourth sequence, the control device may use half of the sum of the total number n and the preset value n0 as the target number of each energy storage submodule to be put into operation on the first side of the first node, and use half of the difference between the total number n and the preset value n0 as the target number of each energy storage submodule to be put into operation on the second side of the first node. If the SOC of the (n-n0) / 2+1th energy storage submodule in the third sequence is less than the SOC of the (n-n0) / 2+1th energy storage submodule in the fourth sequence, the control device may use half of the sum of the total number n and the preset value n0 as the target number of each energy storage submodule to be put into operation on the second side of the first node, and use half of the difference between the total number n and the preset value n0 as the target number of each energy storage submodule to be put into operation on the first side of the first node.

[0213] It can be seen that in this implementation, by determining the number of target-connected energy storage submodules located on the first side of the first node and the number of target-connected energy storage submodules located on the second side of the first node to be equal to different values ​​of one-half the difference between the total number and the preset value and one-half the sum of the total number and the preset value, respectively, it is possible to achieve that the difference in the number of target-connected energy storage submodules located on the first side and the second side of the first node can be 1, so that when the switching state and / or switching position of the energy storage submodules in the energy storage device fluctuates, the voltage across the energy storage device can be basically stably controlled at the corresponding expected voltage, thereby facilitating further improving the voltage stability across the energy storage device.

[0214] In summary, in an embodiment of the present application, the total number of target energy storage submodules located on both sides of the first node is determined based on the expected voltage and the first average voltage of each energy storage submodule. Further, based on the total number, the number of target energy storage submodules located on the first side of the first node and the number of target energy storage submodules located on the second side of the first node are determined. It can be seen that in an embodiment of the present application, the number of target energy storage submodules located on the first side of the first node and the number of target energy storage submodules located on the second side of the first node are determined in accordance with the overall voltage control sub-strategy based on the expected voltage and the first average voltage of each energy storage submodule. The number of target energy storage submodules located on the first side of the first node and the number of target energy storage submodules located on the second side of the first node can be determined more comprehensively and reasonably.

[0215] In some embodiments, FIG16 is a flow chart of a method for determining the number of target energy storage submodules to be put into operation on the first side of a first node provided in some embodiments of the present application. Based on the above embodiments, the present application introduces a possible implementation of the above step S1303A of "determining the number of target energy storage submodules to be put into operation on the first side of the first node based on the expected voltage and the measured voltage of each energy storage submodule." As shown in FIG16, the above step S1303A may include the following steps:

[0216] Step S1601: When the deviation percentage of the actually measured voltages of the energy storage submodules located on the first side of the first node is less than 10%, determine a second average voltage of the energy storage submodules on the first side according to the actually measured voltages of the energy storage submodules located on the first side of the first node.

[0217] In this step, when the deviation percentage of the actually measured voltages of the energy storage submodules located on the first side of the first node is less than 10%, the control device can determine the second average voltage of the energy storage submodules on the first side according to the group voltage control sub-strategy based on the actually measured voltages of the energy storage submodules located on the first side of the first node.

[0218] Exemplarily, the control device may determine the second average voltage of each energy storage submodule on the first side according to the measured voltage of each energy storage submodule on the first side of the first node with reference to the following formula (3).

[0219] Wherein, Uc1i represents the voltage of the i-th energy storage submodule located on the first side of the first node, and Uc-avg2 represents the second average voltage.

[0220] Of course, the control device may determine the second average voltage of each energy storage submodule on the first side according to the measured voltage of each energy storage submodule on the first side of the first node, or by referring to other modified formulas or equivalent formulas of the above formula (3).

[0221] Step S1602: Determine the number of target-connected energy storage submodules located on the first side of the first node according to the expected voltage and the second average voltage.

[0222] In this step, the control device may determine the number of target-connected energy storage submodules located on the first side of the first node according to the expected voltage and the second average voltage and in accordance with the group voltage control sub-strategy.

[0223] Exemplarily, the control device may determine the number of target energy storage submodules to be put into operation on the first side of the first node according to the expected voltage and the second average voltage with reference to the following formula (4).

[0224] Wherein, n1 represents the number of target-input energy storage submodules located on the first side of the first node.

[0225] It should be noted that, when the expected voltage and the second average voltage cannot be divided evenly, the number of target energy storage submodules to be put into operation on the first side of the first node can be determined by rounding off to an integer.

[0226] Of course, the control device may also determine the number of target energy storage submodules to be put into operation on the first side of the first node based on the expected voltage and the second average voltage, or by referring to other modified formulas or equivalent formulas of the above formula (4).

[0227] It should be noted that the control device can determine the number of each target energy storage sub-module located on the second side of the first node according to the overall voltage control sub-strategy based on the expected voltage and the measured voltage of each energy storage sub-module, or can determine the number of each target energy storage sub-module located on the second side of the first node according to the group voltage control sub-strategy, or can determine the number of each target energy storage sub-module located on the second side of the first node by other means.

[0228] In summary, in the embodiment of the present application, when the deviation percentage of the measured voltage of each energy storage submodule located on the first side of the first node is less than 10%, the second average voltage of each energy storage submodule located on the first side of the first node is determined based on the measured voltage of each energy storage submodule located on the first side of the first node, and the number of each target energy storage submodule to be put into operation on the first side of the first node is determined based on the expected voltage and the second average voltage. It can be seen that in the embodiment of the present application, by determining the number of each target energy storage submodule to be put into operation on the first side of the first node according to the group voltage control sub-strategy based on the expected voltage and the measured voltage of each energy storage submodule located on the first side of the first node, the number of each target energy storage submodule to be put into operation on the first side of the first node can be determined more flexibly and accurately.

[0229] In some embodiments, FIG17 is a flow chart of a method for determining the number of target energy storage submodules to be put into operation on the second side of a first node provided in some embodiments of the present application. Based on the above embodiments, the present application introduces a possible implementation of the above step S1303A of "determining the number of target energy storage submodules to be put into operation on the second side of the first node based on the expected voltage and the measured voltage of each energy storage submodule." As shown in FIG17, the above step S1303A may include the following steps:

[0230] Step S1701: When the deviation percentage of the actually measured voltages of the energy storage submodules located on the second side of the first node is less than 10%, determine a third average voltage of the energy storage submodules on the second side according to the actually measured voltages of the energy storage submodules located on the second side of the first node.

[0231] In this step, when the deviation percentage of the measured voltage of each energy storage sub-module located on the second side of the first node is less than 10%, the control device can determine the third average voltage of each energy storage sub-module on the second side according to the group voltage control sub-strategy based on the measured voltage of each energy storage sub-module located on the second side of the first node.

[0232] Exemplarily, the control device may determine the third average voltage of each energy storage submodule on the second side according to the measured voltage of each energy storage submodule on the second side of the first node with reference to the following formula (5).

[0233] Wherein, Uc2i represents the voltage of the i-th energy storage submodule located on the second side of the first node, and Uc-avg3 represents the third average voltage.

[0234] Of course, the control device may determine the third average voltage of each energy storage submodule on the second side according to the voltage of each energy storage submodule on the second side of the first node, or by referring to other modified formulas or equivalent formulas of the above formula (5).

[0235] Step S1702: Determine the number of target energy storage submodules to be put into operation on the second side of the first node according to the expected voltage and the third average voltage.

[0236] In this step, the control device may determine the number of target-connected energy storage submodules located on the second side of the first node according to the expected voltage and the third average voltage and in accordance with the group voltage control sub-strategy.

[0237] Exemplarily, the control device may determine the number of target energy storage submodules to be put into operation on the second side of the first node according to the expected voltage and the third average voltage with reference to the following formula (6).

[0238] Wherein, n2 represents the number of target-input energy storage submodules located on the second side of the first node.

[0239] It should be noted that, when the expected voltage and the third average voltage cannot be divided evenly, the number of target energy storage submodules to be put into operation on the second side of the first node can be determined by rounding off to an integer.

[0240] Of course, the control device may also determine the number of target energy storage submodules to be put into operation on the second side of the first node based on the expected voltage and the third average voltage, or by referring to other modified formulas or equivalent formulas of the above formula (6).

[0241] It should be noted that the control device can determine the number of each target energy storage sub-module located on the first side of the first node according to the overall voltage control sub-strategy based on the expected voltage and the measured voltage of each energy storage sub-module, or can determine the number of each target energy storage sub-module located on the first side of the first node according to the group voltage control sub-strategy, or can determine the number of each target energy storage sub-module located on the first side of the first node by other means.

[0242] In summary, in the embodiment of the present application, when the deviation percentage of the measured voltage of each energy storage submodule located on the second side of the first node is less than 10%, the third average voltage of each energy storage submodule located on the second side of the first node is determined based on the measured voltage of each energy storage submodule located on the second side of the first node, and the number of each target energy storage submodule located on the second side of the first node is determined based on the expected voltage and the third average voltage. It can be seen that in the embodiment of the present application, by determining the number of each target energy storage submodule located on the second side of the first node according to the group voltage control sub-strategy based on the expected voltage and the measured voltage of each energy storage submodule located on the second side of the first node, the number of each target energy storage submodule located on the second side of the first node can be determined more flexibly and accurately.

[0243] In some embodiments, FIG18 is a flow chart of a control method for controlling each target-input energy storage submodule on both sides of the first node to be in a cut-in state provided by some embodiments of the present application. Based on the above embodiments, the embodiments of the present application introduce a possible implementation method of the above step S1303B of "controlling each target-input energy storage submodule on both sides of the first node in the first energy storage trunk line to be in a cut-in state according to the number of each target-input energy storage submodule located on the first side of the first node and the number of each target-input energy storage submodule located on the second side of the first node". As shown in FIG18, the above step S1303B may include the following steps:

[0244] Step S1801: Obtain the charge and discharge status of the energy storage device and the measured SOC of each energy storage submodule.

[0245] For example, the charge and discharge state of the energy storage device in the embodiment of the present application may include but is not limited to a charge state or a discharge state.

[0246] It should be understood that the energy storage device may be provided with a state detection unit for detecting the charge and discharge state of the energy storage device, and an SOC detection unit for detecting the measured SOC of each energy storage submodule.

[0247] Step S1802: Control each target-input energy storage submodule on both sides of the first node in the first energy storage trunk line to be in a cut-in state based on the number of each target-input energy storage submodule located on the first side of the first node, the number of each target-input energy storage submodule located on the second side of the first node, the charge and discharge status of the energy storage device, and the measured SOC of each energy storage submodule.

[0248] In this step, on the one hand, the control device can control each target input energy storage submodule located on the first side of the first node to be in the cut-in state based on the number of each target input energy storage submodule located on the first side of the first node, the measured SOC of each energy storage submodule located on the first side of the first node, and the charge and discharge state of the energy storage device, so as to charge and discharge the energy storage submodule located on the first side of the first node that is more in need of charging and discharging. On the other hand, the control device can control each target input energy storage submodule located on the second side of the first node to be in the cut-in state based on the number of each target input energy storage submodule located on the second side of the first node, the measured SOC of each energy storage submodule located on the second side of the first node, and the charge and discharge state of the energy storage device, so as to charge and discharge the energy storage submodule located on the second side of the first node that is more in need of charging and discharging.

[0249] It can be seen that in the embodiment of the present application, by further considering the measured SOC of each energy storage submodule and the charge and discharge state of the energy storage device based on the number of each target input energy storage submodule located on the first side of the first node and the number of each target input energy storage submodule located on the second side of the first node, it is possible to charge and discharge the energy storage submodules located on both sides of the first node that are more in need of charging and discharging. This can not only help improve the stability of the voltage at both ends of the energy storage device, but also help improve the charge and discharge balance of each energy storage submodule of the energy storage device.

[0250] In one possible implementation, when the charge and discharge state of the energy storage device is a charging state, the first n1 energy storage submodules located on the first side of the first node are respectively used as target input submodules in order from low to high measured SOCs of the energy storage submodules located on the first side of the first node, and the target input submodules are controlled to be in a cut-in state; wherein n1 is the number of the target input energy storage submodules located on the first side of the first node; and the first n2 energy storage submodules located on the second side of the first node are respectively used as target input submodules in order from low to high measured SOCs of the energy storage submodules located on the second side of the first node, and the target input submodules are controlled to be in a cut-in state; wherein n2 is the number of the target input energy storage submodules located on the second side of the first node.

[0251] In this implementation, when the charge / discharge state of the energy storage device is the charging state, the control device may, on the one hand, select the first n1 energy storage submodules located on the first side of the first node as target input energy storage submodules in ascending order of the SOCs of the energy storage submodules located on the first side of the first node, and control these target input energy storage submodules to be in the cut-in state, so as to charge the first n1 energy storage submodules located on the first side of the first node with relatively low SOCs. On the other hand, the control device may select the first n2 energy storage submodules located on the second side of the first node as target input energy storage submodules in ascending order of the SOCs of the energy storage submodules located on the second side of the first node, and control these target input energy storage submodules to be in the cut-in state, so as to charge the first n2 energy storage submodules located on the second side of the first node with relatively low SOCs.

[0252] It can be seen that in this implementation, when the charge and discharge state of the energy storage device is the charging state, by further considering the measured SOC of each energy storage sub-module based on the number of target-input energy storage sub-modules located on both sides of the first node, multiple energy storage sub-modules located on both sides of the first node with relatively low measured SOCs can be charged as target-input energy storage sub-modules. This can not only help improve the stability of the voltage at both ends of the energy storage device, but also help improve the charging balance of the energy storage sub-modules located on both sides of the first node.

[0253] In another possible implementation, when the charge and discharge state of the energy storage device is the discharge state, the first n1 energy storage sub-modules located on the first side of the first node are respectively selected as target input sub-modules in descending order of the measured SOCs of the energy storage sub-modules located on the first side of the first node, and each target input sub-module is controlled to be in the cut-in state; and the first n2 energy storage sub-modules located on the second side of the first node are respectively determined as target input sub-modules in descending order of the measured SOCs of the energy storage sub-modules located on the second side of the first node, and each target input sub-module is controlled to be in the cut-in state.

[0254] In this implementation, when the energy storage device is in the discharge state, the control device may, on the one hand, select the first n1 energy storage submodules located on the first side of the first node as target input submodules in descending order of the SOCs of the energy storage submodules located on the first side of the first node, and control these target input submodules to be in the cut-in state, so as to facilitate discharge of the first n1 energy storage submodules located on the first side of the first node with relatively high SOCs. On the other hand, the control device may select the first n2 energy storage submodules located on the second side of the first node as target input submodules in descending order of the SOCs of the energy storage submodules located on the second side of the first node, and control these target input submodules to be in the cut-in state, so as to facilitate discharge of the first n2 energy storage submodules located on the second side of the first node with relatively high SOCs.

[0255] It can be seen that in this implementation, when the charge and discharge state of the energy storage device is the discharge state, by further considering the measured SOC of each energy storage sub-module based on the number of target-input energy storage sub-modules located on the second side of the first node, multiple energy storage sub-modules with relatively high measured SOCs located on both sides of the first node can be used as target-input energy storage sub-modules for discharge. This can not only help improve the stability of the voltage at both ends of the energy storage device, but also help improve the charging balance of each energy storage sub-module located on both sides of the first node.

[0256] In some embodiments, based on the above embodiments, for ease of understanding, the present application takes the above preset value n0 as 1 as an example to introduce the overall process of the above overall voltage control sub-strategy.

[0257] 1) The control device can obtain the expected voltage of the energy storage device.

[0258] 2) The control device may obtain the measured voltage of each energy storage submodule of the first energy storage trunk line in the energy storage device and determine a first average voltage of each energy storage submodule based on the measured voltage of each energy storage submodule. The deviation percentage of the measured voltage of each energy storage submodule may be less than 10%.

[0259] 3) The control device may determine the total number n of target energy storage submodules to be put into operation on both sides of the first node according to the expected voltage and the first average voltage.

[0260] 4a) The charge and discharge state of the energy storage device is the charging state

[0261] 4a1) With the first node in the first energy storage trunk line as the boundary, the control device may obtain a first sequence by sorting the energy storage submodules located on the first side of the first node in ascending order according to the measured SOC, and obtain a second sequence by sorting the energy storage submodules located on the second side of the first node in ascending order according to the measured SOC.

[0262] 4a2) If the total number n is an even number, the control device can control the first n / 2 (i.e., n1) energy storage sub-modules in the first sequence as target input sub-modules and control these target input sub-modules to be in the cut-in state, and control the first n / 2 (i.e., n2) energy storage sub-modules in the second sequence as target input sub-modules and control these target input sub-modules to be in the cut-in state.

[0263] If the total number n is an odd number, the control device can control the first (n-1) / 2 energy storage submodules in the first sequence as target input submodules, and control these target input submodules to be in the cut-in state, and control the first (n-1) / 2 energy storage submodules in the second sequence as target input submodules, and control these target input submodules to be in the cut-in state; further, the control device can control the (n-1) / 2+1th energy storage submodule in the first sequence and the (n-1) / 2+1th energy storage submodule in the second sequence with a relatively low measured SOC as target input submodules, and control the target input submodule to be in the switching state.

[0264] 4b) The charge and discharge state of the energy storage device is the discharge state

[0265] 4b1) With the first node in the first energy storage trunk line as the boundary, the control device may obtain a third sequence by sorting the energy storage sub-modules located on the first side of the first node in descending order according to the measured SOC, and obtain a fourth sequence by sorting the energy storage sub-modules located on the second side of the first node in descending order according to the measured SOC.

[0266] 4b2) If the total number n is an even number, the control device can control the first n / 2 (i.e., n1) energy storage sub-modules in the third sequence as target input sub-modules, and control these target input sub-modules to be in the cut-in state, and control the first n / 2 (i.e., n2) energy storage sub-modules in the fourth sequence as target input sub-modules, and control these target input sub-modules to be in the cut-in state.

[0267] If the total number n is an odd number, the control device can control the first (n-1) / 2 energy storage submodules in the third sequence as target input submodules, and control these target input submodules to be in the cut-in state, and control the first (n-1) / 2 energy storage submodules in the fourth sequence as target input submodules, and control these target input submodules to be in the cut-in state; further, the control device can control the energy storage submodule with a relatively high measured SOC among the (n-1) / 2+1th energy storage submodule in the third sequence and the (n-1) / 2+1th energy storage submodule in the fourth sequence as the target input submodule, and control the target input submodule to be in the switching state.

[0268] It should be noted that the implementation principles and technical effects of each step in the embodiment of the present application are similar to the relevant contents in the above embodiment and will not be repeated here.

[0269] In some embodiments, based on the above embodiments, for ease of understanding, the overall process of the above group voltage control sub-strategy is introduced in the embodiments of the present application.

[0270] 1) The control device can obtain the expected voltage of the energy storage device.

[0271] 2) The control device may obtain the measured voltage of each energy storage submodule of the first energy storage trunk line in the energy storage device, wherein the deviation percentage of the measured voltage of each energy storage submodule may be less than 10%.

[0272] 3) The control device can determine the second average voltage of each energy storage submodule on the first side based on the measured voltage of each energy storage submodule located on the first side of the first node, and determine the third average voltage of each energy storage submodule on the second side based on the measured voltage of each energy storage submodule located on the second side of the first node.

[0273] 4) The control device can determine the target number n1 of each energy storage submodule located on the first side of the first node based on the expected voltage and the second average voltage, and determine the target number n2 of each energy storage submodule located on the second side of the first node based on the expected voltage and the third average voltage.

[0274] 5a) The charge and discharge state of the energy storage device is the charging state

[0275] 5a1) With the first node in the first energy storage trunk line as the boundary, the control device may obtain a first sequence by sorting the energy storage submodules located on the first side of the first node in ascending order according to the measured SOC, and obtain a second sequence by sorting the energy storage submodules located on the second side of the first node in ascending order according to the measured SOC.

[0276] 5a2) The control device can control the first n1 energy storage submodules in the first sequence as target input submodules, and control these target input submodules to be in the cut-in state, and control the first n2 energy storage submodules in the second sequence as target input submodules, and control these target input submodules to be in the cut-in state.

[0277] 5b) The charge and discharge state of the energy storage device is the discharge state

[0278] 5b1) With the first node in the first energy storage trunk line as the boundary, the control device may obtain a third sequence by sorting the energy storage submodules located on the first side of the first node in descending order according to the measured SOC, and obtain a fourth sequence by sorting the energy storage submodules located on the second side of the first node in descending order according to the measured SOC. 5b2) The control device may control the first n1 energy storage submodules in the third sequence to serve as target input submodules, and control these target input submodules to be in the cut-in state, and control the first n2 energy storage submodules in the fourth sequence to serve as target input submodules, and control these target input submodules to be in the cut-in state.

[0279] It should be noted that the implementation principles and technical effects of each step in the embodiment of the present application are similar to the relevant contents in the above embodiment and will not be repeated here.

[0280] It should be understood that, although the steps in the flowcharts of the above embodiments are shown in sequence as indicated by the arrows, these steps are not necessarily performed 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 performed in other orders. Moreover, at least a portion of the steps in the flowcharts of the above embodiments may include multiple steps or multiple stages, and these steps or stages are not necessarily performed at the same time, but can be performed at different times. The execution order of these steps or stages is not necessarily to be performed in sequence, but can be performed in turn or alternately with other steps or at least a portion of steps or stages in other steps.

[0281] Based on the same inventive concept, embodiments of the present application also provide a control device for implementing the aforementioned method for controlling an energy storage device. The solution provided by this device is similar to the solution described in the aforementioned method. Therefore, the specific limitations in the embodiments of the control device for one or more energy storage devices provided below can be found in the aforementioned definition of the method for controlling an energy storage device, and will not be further elaborated here.

[0282] In some embodiments, Figure 19 is a schematic diagram of the structure of a control device for an energy storage device provided in some embodiments of the present application. The energy storage device in the embodiments of the present application may be the energy storage device in the high-voltage direct-mounted energy storage system embodiment described above. For its specific structure, reference may be made to the relevant content in the above embodiments and will not be repeated here. As shown in Figure 19, the control device for the energy storage device in the embodiments of the present application may include: a first acquisition module 1901, a second acquisition module 1902, and a control module 1903.

[0283] A first acquisition module 1901 is configured to acquire an expected voltage of an energy storage device;

[0284] A second acquisition module 1902 is configured to acquire measured voltages of at least two energy storage submodules connected to a first energy storage trunk line in the energy storage device;

[0285] Control module 1903 controls each target-enabled energy storage submodule on both sides of a first node in a first energy storage trunk line to be in a cut-in state based on the expected voltage and the measured voltages of at least two energy storage submodules, wherein the difference between the sum of the voltage amplitudes of each target-enabled energy storage submodule on both sides of the first node is less than a preset threshold, and the difference between the total voltage of the energy storage device and the expected voltage is less than a preset difference.

[0286] In some embodiments, the control module 1903 includes:

[0287] a determining unit, configured to determine, based on the expected voltage and the measured voltage of each energy storage submodule, the number of target energy storage submodules to be put into operation on the first side of the first node and the number of target energy storage submodules to be put into operation on the second side of the first node;

[0288] A control unit is used to control the target energy storage submodules on both sides of the first node in the first energy storage trunk line to be in a cut-in state according to the number of the target energy storage submodules located on the first side of the first node and the number of the target energy storage submodules located on the second side of the first node.

[0289] In some embodiments, the determining unit is specifically configured to:

[0290] When the deviation percentage of the measured voltage of each energy storage submodule is less than 10%, determining a first average voltage of each energy storage submodule according to the measured voltage of each energy storage submodule;

[0291] Determining the total number of target energy storage submodules located on both sides of the first node according to the expected voltage and the first average voltage;

[0292] Based on the total quantity, the quantity of each target put-into-energy storage submodule located on a first side of the first node and the quantity of each target put-into-energy storage submodule located on a second side of the first node are determined.

[0293] In some embodiments, the determining unit is specifically configured to:

[0294] If the total number is an even number, determining that the number of each target put-into-energy storage submodule located on the first side of the first node and the number of each target put-into-energy storage submodule located on the second side of the first node are both equal to one-half of the total number;

[0295] If the total number is an odd number, the number of each target put-into-energy storage submodule located on the first side of the first node and the number of each target put-into-energy storage submodule located on the second side of the first node are determined to be equal to the different values ​​of half of the difference between the total number and the preset value and half of the sum of the total number and the preset value, respectively.

[0296] In some embodiments, the determining unit is specifically configured to:

[0297] When the deviation percentage of the measured voltages of the energy storage submodules located on the first side of the first node is less than 10%, determining a second average voltage of the energy storage submodules on the first side according to the measured voltages of the energy storage submodules located on the first side of the first node;

[0298] The number of target energy storage submodules to be put into operation on the first side of the first node is determined according to the expected voltage and the second average voltage.

[0299] In some embodiments, the determining unit is specifically configured to:

[0300] When the deviation percentage of the measured voltages of the energy storage submodules located on the second side of the first node is less than 10%, determining a third average voltage of the energy storage submodules on the second side according to the measured voltages of the energy storage submodules located on the second side of the first node;

[0301] The number of target energy storage submodules to be put into operation on the second side of the first node is determined according to the expected voltage and the third average voltage.

[0302] In some embodiments, the control unit is specifically configured to:

[0303] Obtain the charge and discharge status of the energy storage device and the measured SOC of each energy storage submodule;

[0304] According to the number of target energy storage submodules located on the first side of the first node, the number of target energy storage submodules located on the second side of the first node, the charge and discharge status of the energy storage device, and the measured SOC of each energy storage submodule, the target energy storage submodules on both sides of the first node in the first energy storage trunk line are controlled to be in the cut-in state.

[0305] In some embodiments, the control unit is specifically configured to:

[0306] When the energy storage device is in a charging state, the first n1 energy storage submodules located on the first side of the first node are respectively selected as target input submodules in ascending order of the measured SOCs of the energy storage submodules located on the first side of the first node, and each target input submodule is controlled to be in a cut-in state; wherein n1 is the number of target input energy storage submodules located on the first side of the first node;

[0307] According to the order of the measured SOC of each energy storage submodule located on the second side of the first node from low to high, the first n2 energy storage submodules located on the second side of the first node are respectively used as target input submodules, and each target input submodule is controlled to be in the cut-in state; wherein n2 is the number of each target input energy storage submodule located on the second side of the first node.

[0308] In some embodiments, the control unit is specifically configured to:

[0309] When the energy storage device is in a discharge state, first n1 energy storage submodules located on the first side of the first node are respectively selected as target input submodules in descending order of the measured SOCs of the energy storage submodules located on the first side of the first node, and each target input submodule is controlled to be in a cut-in state;

[0310] According to the measured SOC of each energy storage submodule located on the second side of the first node from high to low, the first n2 energy storage submodules located on the second side of the first node are determined as target input submodules, and each target input submodule is controlled to be in the cut-in state.

[0311] The control device of the energy storage device provided in the embodiment of the present application can be used to execute the technical solution in the embodiment of the control method of the energy storage device described above. The implementation principle and technical effects thereof are similar and will not be described in detail here.

[0312] Each module in the control device of the energy storage device described above may be implemented in whole or in part through software, hardware, or a combination thereof. Each module may be embedded in or independent of the processor in the control device in hardware form, or may be stored in memory in the control device in software form, so that the processor can call and execute the corresponding operations of each module.

[0313] In some embodiments, a control device for an energy storage device is also provided, including a memory and a processor. The memory stores a computer program, and when the processor executes the computer program, the technical solution in the control method embodiment of the above-mentioned energy storage device of the present application is implemented. Its implementation principle and technical effect are similar and will not be repeated here.

[0314] In some embodiments, a computer-readable storage medium is further provided, on which a computer program is stored. When the computer program is executed by a processor, the technical solution in the control method embodiment of the above-mentioned energy storage device of the present application is implemented. The implementation principle and technical effect are similar and will not be repeated here.

[0315] In some embodiments, a computer program product is also provided, including a computer program. When the computer program is executed by a processor, the technical solution in the control method embodiment of the energy storage device of the present application is implemented. The implementation principle and technical effect are similar and will not be repeated here.

[0316] Those skilled in the art will appreciate that all or part of the processes in the above-mentioned embodiments 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. For purposes of illustration and not limitation, RAM may be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The processors involved in the various embodiments provided herein may be general-purpose processors, central processing units (CPUs), graphics processors (GPUs), digital signal processors (DSPs), programmable logic devices (PLDs), data processing logic devices based on quantum computing, and the like, without limitation thereto.

[0317] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A high-voltage direct-mounted energy storage system, comprising: A clamping circuit, comprising a first clamping branch and a second clamping branch; An energy storage device, comprising a first energy storage trunk line and at least two energy storage submodules connected to the first energy storage trunk line, wherein two ends of the first energy storage trunk line are respectively connected to the clamping circuit; and at least one dielectric branch, one end of which is connected to at least one of the energy storage submodules, and the other end of which is coupled to a reference ground; and also includes a first node arranged on the first energy storage trunk line and a first grounding circuit connected to the first node, wherein the resistance of the first grounding circuit is less than a preset resistance threshold; A control device is used to control each target-input energy storage submodule on both sides of the first node to be in a cut-in state according to the expected voltage of the energy storage device and the measured voltages of at least two of the energy storage submodules connected to the first energy storage trunk line, wherein the difference between the sum of the voltage amplitudes of each of the target-input energy storage submodules located on both sides of the first node is less than a preset threshold value, and the difference between the total voltage of the energy storage device and the expected voltage is less than a preset difference.

2. The high-voltage direct-mounted energy storage system according to claim 1, wherein: The sum of voltage amplitudes of the energy storage submodules located on each side of the first node is greater than or equal to one half of the expected voltage of the energy storage device.

3. The high-voltage direct-mounted energy storage system according to claim 1 or 2, wherein: The deviation percentage of the measured voltage of each energy storage submodule is less than 10%, and the number of the target energy storage submodules located on both sides of the first node is equal or differs by 1.

4. The high-voltage direct-mounted energy storage system according to any one of claims 1 to 3, wherein: The first grounding circuit is a conductor, or includes a grounding resistor or a grounding reactor.

5. The high-voltage direct-mounted energy storage system according to any one of claims 1 to 4, wherein: The preset resistance threshold is the product of the resistance value of the first clamping branch and 0.02; optionally, the preset resistance threshold is the product of the resistance value of the first clamping branch and 0.

001.

6. The high-voltage direct-mounted energy storage system according to any one of claims 1 to 5, wherein: The first grounding circuit further includes a current detection unit.

7. The high-voltage direct-mounted energy storage system according to any one of claims 1 to 6, wherein: The energy storage device further includes at least one second energy storage trunk line and at least two energy storage submodules connected to the second energy storage trunk line, and the second energy storage trunk line is connected in parallel with the first energy storage trunk line.

8. The high-voltage direct-mounted energy storage system according to claim 7, wherein: The energy storage device also includes a second node arranged on the second energy storage trunk line and a second grounding circuit connected to the second node, and the resistance of the second grounding circuit is less than the preset resistance threshold.

9. The high-voltage direct-mounted energy storage system according to claim 8, wherein: The sum of voltage amplitudes of the energy storage submodules located on each side of the second node is greater than or equal to one half of the expected voltage of the energy storage device.

10. The high-voltage direct-mounted energy storage system according to any one of claims 1 to 9, wherein: The high-voltage direct-mounted energy storage system also includes a converter valve, a positive DC bus and a negative DC bus. The first end of the converter valve is connected to the positive DC bus, the second end of the converter valve is connected to the negative DC bus, the third end of the converter valve is connected to the AC power grid, and the two ends of the first energy storage trunk line are respectively connected to the positive DC bus and the negative DC bus.

11. The high-voltage direct-mounted energy storage system according to any one of claims 1 to 10, wherein: The medium branch includes at least one of a cooling branch, a fire protection branch and a heat medium branch.

12. A method for controlling an energy storage device, wherein: The energy storage device is an energy storage device in a high-voltage direct-mounted energy storage system according to any one of claims 1 to 11, and the method comprises: Obtaining an expected voltage of the energy storage device; Acquire measured voltages of at least two energy storage submodules connected to a first energy storage trunk line in the energy storage device; According to the expected voltage and the measured voltages of at least two of the energy storage submodules, each target-input energy storage submodule on both sides of the first node in the first energy storage trunk line is controlled to be in a cut-in state, wherein the difference between the sum of the voltage amplitudes of each target-input energy storage submodule on both sides of the first node is less than a preset threshold, and the difference between the total voltage of the energy storage device and the expected voltage is less than a preset difference.

13. The method according to claim 12, wherein: The step of controlling each target-input energy storage submodule on both sides of the first node in the first energy storage trunk line to be in a cut-in state according to the expected voltage and the measured voltages of at least two of the energy storage submodules includes: Determine, according to the expected voltage and the measured voltage of each of the energy storage submodules, the number of each target put-into energy storage submodule located on the first side of the first node and the number of each target put-into energy storage submodule located on the second side of the first node; According to the number of each target energy storage submodule located on the first side of the first node and the number of each target energy storage submodule located on the second side of the first node, each target energy storage submodule on both sides of the first node in the first energy storage trunk line is controlled to be in a cut-in state.

14. The method according to claim 13, wherein: The step of determining, according to the expected voltage and the measured voltage of each of the energy storage submodules, the number of each target put-into-energy storage submodule located on the first side of the first node and the number of each target put-into-energy storage submodule located on the second side of the first node comprises: When the deviation percentage of the measured voltage of each energy storage submodule is less than 10%, determining the first average voltage of each energy storage submodule according to the measured voltage of each energy storage submodule; Determining the total number of target energy storage submodules located on both sides of the first node according to the expected voltage and the first average voltage; Based on the total number, the number of each target put-into-energy storage submodule located on the first side of the first node and the number of each target put-into-energy storage submodule located on the second side of the first node are determined.

15. The method according to claim 14, wherein: The determining, based on the total quantity, the quantity of each target put-into-energy storage submodule located on the first side of the first node and the quantity of each target put-into-energy storage submodule located on the second side of the first node comprises: If the total number is an even number, determining that the number of each target put-into-energy storage submodule located on the first side of the first node and the number of each target put-into-energy storage submodule located on the second side of the first node are both equal to one-half of the total number; If the total number is an odd number, the number of each target energy storage sub-module located on the first side of the first node and the number of each target energy storage sub-module located on the second side of the first node are determined to be equal to different values ​​of half of the difference between the total number and the preset value and half of the sum of the total number and the preset value, respectively.

16. The method according to claim 13, wherein: The step of determining the number of each target input energy storage submodule located on the first side of the first node according to the expected voltage and the measured voltage of each energy storage submodule includes: When the deviation percentage of the measured voltage of each of the energy storage submodules located on the first side of the first node is less than 10%, Determining a second average voltage of each energy storage submodule on the first side according to the measured voltage of each energy storage submodule on the first side of the first node; The number of each target energy storage submodule to be put into operation on the first side of the first node is determined according to the expected voltage and the second average voltage.

17. The method according to claim 13, wherein: Determining the number of each target input energy storage submodule located on the second side of the first node according to the expected voltage and the measured voltage of each energy storage submodule includes: When the deviation percentage of the measured voltage of each energy storage submodule located on the second side of the first node is less than 10%, determining a third average voltage of each energy storage submodule on the second side according to the measured voltage of each energy storage submodule located on the second side of the first node; The number of each target energy storage submodule to be put into operation on the second side of the first node is determined according to the expected voltage and the third average voltage.

18. The method according to any one of claims 13 to 17, wherein: The controlling each target put-in energy storage submodule on both sides of the first node in the first energy storage trunk line to be in a cut-in state according to the number of each target put-in energy storage submodule located on the first side of the first node and the number of each target put-in energy storage submodule located on the second side of the first node comprises: Obtaining the charge and discharge status of the energy storage device and the measured SOC of each of the energy storage submodules; According to the number of target energy storage submodules located on the first side of the first node, the number of target energy storage submodules located on the second side of the first node, the charge and discharge status of the energy storage device, and the measured SOC of each energy storage submodule, the target energy storage submodules on both sides of the first node in the first energy storage trunk line are controlled to be in a cut-in state.

19. The method according to claim 18, wherein: The method of controlling each target energy storage submodule on both sides of the first node in the first energy storage trunk line to be in a cut-in state according to the number of each target energy storage submodule located on the first side of the first node, the number of each target energy storage submodule located on the second side of the first node, the charge and discharge state of the energy storage device, and the measured SOC of each energy storage submodule comprises: When the charge and discharge state of the energy storage device is a charging state, the first n1 energy storage submodules located on the first side of the first node are respectively used as target input submodules according to the order of the measured SOC of each energy storage submodule located on the first side of the first node from low to high, and each of the target input submodules is controlled to be in a cut-in state; wherein n1 is the number of each target input energy storage submodule located on the first side of the first node; According to the order of the measured SOCs of the energy storage submodules located on the second side of the first node from low to high, the first n2 energy storage submodules located on the second side of the first node are respectively used as target input submodules, and each of the target input submodules is controlled to be in a cut-in state; wherein n2 is the number of each target input energy storage submodule located on the second side of the first node.

20. The method according to claim 18, wherein: The method of controlling each target energy storage submodule on both sides of the first node in the first energy storage trunk line to be in a cut-in state according to the number of each target energy storage submodule located on the first side of the first node, the number of each target energy storage submodule located on the second side of the first node, the charge and discharge state of the energy storage device, and the measured SOC of each energy storage submodule comprises: When the charge and discharge state of the energy storage device is a discharge state, in descending order of the measured SOCs of the energy storage submodules located on the first side of the first node, the first n1 energy storage submodules located on the first side of the first node are respectively used as target input submodules, and each of the target input submodules is controlled to be in a cut-in state; According to the order of the measured SOC of each energy storage submodule located on the second side of the first node from high to low, the first n2 energy storage submodules located on the second side of the first node are determined as target input submodules, and each of the target input submodules is controlled to be in a cut-in state.

21. A control device for an energy storage device, wherein: The energy storage device is the energy storage device in the high-voltage direct-mounted energy storage system according to any one of claims 1 to 11, and the control device includes: A first acquisition module, used to acquire the expected voltage of the energy storage device; A second acquisition module, used to acquire the measured voltages of at least two energy storage submodules connected to the first energy storage trunk line in the energy storage device; A control module controls each target energy storage submodule on both sides of a first node in the first energy storage trunk line to be in a cut-in state according to the expected voltage and the measured voltages of at least two of the energy storage submodules, wherein the difference between the sum of the voltage amplitudes of each target energy storage submodule on both sides of the first node is less than a preset threshold, and the difference between the total voltage of the energy storage device and the expected voltage is less than a preset difference.

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