Energy storage unit SOC balance control method and apparatus thereof, energy storage system, and medium

Abstract

The present application discloses an energy storage unit SOC balance control method and an apparatus thereof, an energy storage system, and a medium. The method comprises: when three-phase energy storage battery modules of an energy storage unit are in an operating state, determining phase-to-phase SOC differences between the three-phase energy storage battery modules; and when a target phase-to-phase SOC difference is greater than or equal to a preset threshold, controlling a first-phase energy storage battery module corresponding to the target phase-to-phase SOC difference to charge a second-phase energy storage battery module corresponding to the target phase-to-phase SOC difference until the target phase-to-phase SOC difference is less than the preset threshold. According to the method, when a phase-to-phase SOC difference between the three-phase energy storage battery modules of the energy storage unit is large, the first-phase energy storage battery module corresponding to the large phase-to-phase SOC difference is controlled to charge the second-phase energy storage battery module until the three-phase energy storage battery modules attain a three-phase SOC balance, which helps to prolong the service life of the energy storage unit.

Description

Energy storage unit SOC equalization control method and device, energy storage system and medium

[0001] This application claims priority to Chinese Patent Application No. 202411547234.8, filed on October 31, 2024, entitled “SOC Equalization Control Method and Device for Energy Storage Unit, Energy Storage System and Medium”, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application belongs to the field of energy storage technology, and in particular relates to a method and device for SOC equalization control of energy storage units, as well as an energy storage system and medium. Background Technology

[0003] After a period of operation, the three-phase state of charge (SOC) of the three-phase energy storage battery modules of the energy storage unit is prone to imbalance due to various reasons.

[0004] Currently, when the three-phase SOC of a three-phase energy storage battery module is unbalanced, the module is prone to overcharging or over-discharging, leading to a shortened lifespan of the energy storage unit. Therefore, SOC balancing control of the energy storage unit is urgently needed.

[0005] Application content

[0006] In view of this, embodiments of this application provide a method and apparatus for SOC balancing control of an energy storage unit, an energy storage system and a medium, to overcome the problems of the prior art. Technical solutions

[0007] The technical solution adopted in the embodiments of this application is:

[0008] In a first aspect, embodiments of this application provide a method for SOC (State of Charge) equalization control of an energy storage unit, including:

[0009] When the three-phase energy storage battery module of the energy storage unit is in operation, determine the SOC difference between each phase of the three-phase energy storage battery module;

[0010] When the target phase-to-phase SOC difference is greater than or equal to a preset threshold, the first phase energy storage battery module corresponding to the target phase-to-phase SOC difference is controlled to charge the second phase energy storage battery module corresponding to the target phase-to-phase SOC difference until the target phase-to-phase SOC difference is less than the preset threshold. The target phase-to-phase SOC difference includes at least one SOC difference among the phase-to-phase SOC differences.

[0011] In some optional embodiments, before the first phase energy storage battery module corresponding to the target phase-to-phase SOC difference charges the second phase energy storage battery module corresponding to the target phase-to-phase SOC difference, the energy storage unit SOC equalization control method further includes:

[0012] Disconnect the energy storage unit from the power grid.

[0013] The first phase energy storage battery module corresponding to the target phase-to-phase SOC difference charges the second phase energy storage battery module corresponding to the target phase-to-phase SOC difference, including:

[0014] When the energy storage unit is disconnected from the grid, the first phase energy storage battery module is controlled to charge the second phase energy storage battery module.

[0015] In some optional embodiments, a load switch is provided between the first-phase energy storage battery module and the second-phase energy storage battery module. Before the first-phase energy storage battery module charges the second-phase energy storage battery module, the SOC balancing control method of the energy storage unit further includes:

[0016] Control the load switch to switch from the open state to the closed state;

[0017] Controlling the first-phase energy storage battery module to charge the second-phase energy storage battery module includes:

[0018] When the load switch is closed, the first phase energy storage battery module is controlled to charge the second phase energy storage battery module.

[0019] In some optional embodiments, before the energy storage unit disconnects its electrical connection with the grid, the SOC balancing control method for the energy storage unit further includes:

[0020] Obtain the off-time of the energy storage unit; the off-time is used to characterize the absence of energy exchange between the grid and the energy storage unit.

[0021] Disconnecting the energy storage unit from the power grid includes:

[0022] In the event of a current off-peak period, the energy storage unit is disconnected from the power grid.

[0023] In some optional embodiments, before the first phase energy storage battery module corresponding to the target phase-to-phase SOC difference charges the second phase energy storage battery module corresponding to the target phase-to-phase SOC difference, the energy storage unit SOC equalization control method further includes:

[0024] The energy storage battery module corresponding to the first phase SOC of the target phase SOC difference is defined as the first phase energy storage battery module.

[0025] The energy storage battery module whose second phase SOC corresponds to the target phase SOC difference is defined as the second phase energy storage battery module, and the first phase SOC is greater than the second phase SOC.

[0026] In some optional embodiments, when the three-phase energy storage battery modules of the energy storage unit are in operation, determining the SOC difference between each phase of the three-phase energy storage battery modules includes:

[0027] When the three-phase energy storage battery module of the energy storage unit is in operation, determine the three-phase SOC of the three-phase energy storage battery module, with each phase SOC corresponding to one phase energy storage battery module.

[0028] The SOC difference between any two phases in the three-phase SOC is determined to obtain the SOC difference between each phase.

[0029] In some optional embodiments, when the three-phase energy storage battery module of the energy storage unit is in operation, determining the three-phase SOC of the three-phase energy storage battery module includes:

[0030] When the three-phase energy storage battery modules of the energy storage unit are in operation, obtain multiple SOCs of multiple energy storage batteries in each phase energy storage battery module, with each SOC corresponding to one energy storage battery.

[0031] The SOC of one phase is determined based on the multiple SOCs of each phase energy storage battery module, resulting in the three-phase SOC.

[0032] In some optional embodiments, the SOC balancing control method for energy storage units further includes:

[0033] When the SOC difference between each phase is less than a preset threshold, the energy storage unit is controlled to switch to hot standby mode.

[0034] Secondly, embodiments of this application provide a SOC balancing control device for an energy storage unit, comprising:

[0035] The difference determination module is used to determine the SOC difference between each phase of the three-phase energy storage battery module when the three-phase energy storage battery module of the energy storage unit is in operation.

[0036] The charging control module is used to control the first phase energy storage battery module corresponding to the target phase SOC difference to charge the second phase energy storage battery module corresponding to the target phase SOC difference when the target phase SOC difference is greater than or equal to a preset threshold, until the target phase SOC difference is less than the preset threshold. The target phase SOC difference includes at least one SOC difference among the phase SOC differences.

[0037] Thirdly, embodiments of this application provide an energy storage system, including:

[0038] Memory;

[0039] One or more processors, coupled to memory;

[0040] One or more applications, wherein one or more applications are stored in memory and configured to be executed by one or more processors, and one or more applications are configured to perform the energy storage unit SOC equalization control method as provided in the first aspect above.

[0041] Fourthly, embodiments of this application provide a computer-readable storage medium storing program code, which can be called by a processor to execute the energy storage unit SOC equalization control method provided in the first aspect above.

[0042] Fifthly, embodiments of this application provide a computer program product that, when run on a computer device, causes the computer device to execute the energy storage unit SOC equalization control method provided in the first aspect above. Beneficial effects

[0043] The beneficial effect of the first aspect provided by the embodiments of this application is that when the interphase SOC difference of the three-phase energy storage battery modules of the energy storage unit is large, the first phase energy storage battery module corresponding to the larger interphase SOC difference is controlled to charge the second phase energy storage battery module until the three-phase SOC of the three-phase energy storage battery modules reaches equilibrium. This can reduce the problem of overcharging or over-discharging of the three-phase energy storage battery modules and help improve the service life of the energy storage unit.

[0044] It is understood that the beneficial effects of the second to fifth aspects mentioned above can be found in the relevant descriptions in the first aspect mentioned above, and will not be repeated here. Attached Figure Description

[0045] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or exemplary technologies will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0046] Figure 1 shows a schematic diagram of a scenario of the energy storage system provided in an embodiment of this application.

[0047] Figure 2 shows a flowchart of a SOC equalization control method for energy storage units provided in an embodiment of this application.

[0048] Figure 3 shows another schematic flowchart of the SOC equalization control method for energy storage units provided in the embodiments of this application.

[0049] Figure 4 shows a schematic diagram of a scenario of an energy storage unit in the SOC equalization control method of the energy storage unit provided in the embodiments of this application.

[0050] Figure 5 shows a schematic diagram of a scenario of the SOC equalization control method for energy storage units provided in an embodiment of this application.

[0051] Figure 6 shows a structural block diagram of an energy storage unit SOC equalization control device provided in an embodiment of this application.

[0052] Figure 7 shows a functional block diagram of an energy storage system provided in an embodiment of this application.

[0053] Figure 8 illustrates a computer-readable storage medium provided in an embodiment of this application for storing or carrying program code implementing the energy storage unit SOC equalization control method provided in an embodiment of this application.

[0054] Figure 9 shows a computer program product provided in an embodiment of this application for storing or carrying program code that implements the SOC equalization control method for energy storage units according to an embodiment of this application. Detailed Implementation

[0055] To make the objectives, features, and advantages of this application more apparent and understandable, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described below are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0056] It should be understood that, when used in this specification and the appended claims, the term "comprising" indicates the presence of the described features, integrals, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or a collection thereof.

[0057] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the scope of the application. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0058] It should also be further understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0059] Furthermore, in the description of this application, the terms "first," "second," "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0060] After a period of operation, the three-phase state of charge (SOC) of the three-phase energy storage battery modules of the energy storage unit is prone to imbalance due to various reasons.

[0061] Currently, when the three-phase SOC of a three-phase energy storage battery module is unbalanced, the module is prone to overcharging or over-discharging, leading to a shortened lifespan of the energy storage unit. Therefore, SOC balancing control of the energy storage unit is urgently needed.

[0062] To address the aforementioned issues, the energy storage unit SOC balancing control method and apparatus, energy storage system, and medium provided in this application, when the three-phase energy storage battery modules of the energy storage unit are in operation, determine the SOC difference between each phase of the three-phase energy storage battery modules. If the target inter-phase SOC difference is greater than or equal to a preset threshold, control the first phase energy storage battery module corresponding to the target inter-phase SOC difference to charge the second phase energy storage battery module corresponding to the target inter-phase SOC difference until the target inter-phase SOC difference is less than the preset threshold. The target inter-phase SOC difference includes at least one of the inter-phase SOC differences. If the inter-phase SOC difference of the three-phase energy storage battery modules of the energy storage unit is large, control the first phase energy storage battery module corresponding to the larger inter-phase SOC difference to charge the second phase energy storage battery module until the three-phase SOC of the three-phase energy storage battery modules reaches equilibrium. This can reduce the problem of overcharging or over-discharging of the three-phase energy storage battery modules and is beneficial to improving the service life of the energy storage unit.

[0063] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings.

[0064] Please refer to Figure 1, which shows a schematic diagram of an application scenario of the energy storage system provided in the embodiment of this application. The energy storage system may include an energy storage unit 100 and a main control device 200. The main control device 200 is communicatively connected to the energy storage unit 100 and interacts with the energy storage unit 100 for data exchange.

[0065] The energy storage unit 100 may include a three-phase energy storage battery module. For example, the three-phase energy storage battery module may be an A-phase energy storage battery module, a B-phase energy storage battery module, and a C-phase energy storage battery module. Each phase energy storage battery module may consist of one or more energy storage batteries.

[0066] As an example, each phase energy storage battery module can be composed of multiple energy storage batteries connected in series and / or in parallel.

[0067] The main control device 200 may be any one of, but not limited to, servers or terminal devices.

[0068] Servers can include, but are not limited to, independent physical servers, server clusters or distributed systems consisting of multiple physical servers, and cloud servers.

[0069] Terminal devices may include, but are not limited to, mobile terminal devices (e.g., mobile phones, PDAs, tablet PCs, laptops, smartwatches, smart bracelets, etc.) and fixed terminal devices (e.g., desktop computers, smart panels, all-in-one computers, etc.).

[0070] In some implementations, the energy storage system may also include a power grid connected to a three-phase energy storage battery module, which can be used to charge and discharge the power grid.

[0071] Please refer to Figure 2, which shows a flowchart of a SOC balancing control method for an energy storage unit according to an embodiment of this application. In a specific embodiment, the SOC balancing control method for an energy storage unit can be applied to the main control device 200 in the energy storage system shown in Figure 1. The process shown in Figure 2 will be described in detail below using the main control device 200 as an example. The SOC balancing control method for an energy storage unit may include the following steps 110 to 130.

[0072] Step 110: With the three-phase energy storage battery module of the energy storage unit in operation, determine the SOC difference between each phase of the three-phase energy storage battery module.

[0073] In this embodiment of the application, when the three-phase energy storage battery module of the energy storage unit is in operation, the main control device can determine the SOC difference between each phase of the three-phase energy storage battery module of the energy storage unit.

[0074] Among them, the phase-to-phase SOC difference can be used to characterize the difference in SOC between different phase energy storage battery modules.

[0075] Specifically, when the three-phase energy storage battery module of the energy storage unit is in operation, the main control equipment can determine the three-phase SOC of the three-phase energy storage battery module of the energy storage unit, and determine the SOC difference between any two phases based on the SOC of the three-phase SOC, thereby obtaining the SOC difference between each phase of the three-phase energy storage battery module. Calculating the SOC difference between each phase based on the three-phase SOC of the three-phase energy storage battery module helps to improve the accuracy of the calculation of the SOC difference between each phase.

[0076] Each phase of SOC can correspond to one phase of energy storage battery module, and each phase of energy storage battery module can be composed of one or more energy storage batteries.

[0077] Regarding the process by which the main control device determines the three-phase SOC of the three-phase energy storage battery module, in some embodiments, each phase energy storage battery module consists of one energy storage battery. The main control device can obtain the SOC of one energy storage battery in each phase energy storage battery module and determine the SOC as the phase SOC of that phase energy storage battery module to obtain the three-phase SOC.

[0078] Regarding the process by which the main control equipment determines the three-phase SOC of the three-phase energy storage battery module, in some embodiments, each phase energy storage battery module is composed of multiple energy storage batteries connected in series and / or in parallel. The main control equipment can obtain one SOC of each energy storage battery in each phase energy storage battery module, obtain multiple SOCs of each phase energy storage battery module, and determine one phase SOC based on the multiple SOCs of each phase energy storage battery module to obtain the three-phase SOC. Calculating one phase SOC of the phase energy storage battery module based on the multiple SOCs of the multiple energy storage batteries in each phase energy storage battery module helps to improve the accuracy of the phase SOC calculation.

[0079] In the case where each phase of the energy storage battery module is composed of multiple energy storage batteries connected in series and / or in parallel, there can be multiple algorithms for calculating the SOC of a phase of the energy storage battery module based on the multiple SOCs of the multiple energy storage batteries in the phase of the energy storage battery module. These algorithms may include, but are not limited to, Algorithm 1 and Algorithm 2.

[0080] Algorithm 1: It can calculate the average SOC of multiple energy storage batteries in each phase energy storage battery module, and determine the average SOC as the phase SOC of one phase energy storage battery module corresponding to multiple energy storage batteries.

[0081] Algorithm 2: First, remove the SOCs corresponding to redundant energy storage batteries from the multiple SOCs to obtain the remaining SOCs. Then, calculate the average value of the remaining SOCs and determine the average value of the remaining SOCs as the SOC of one phase of the energy storage battery module corresponding to the multiple energy storage batteries.

[0082] Redundant energy storage batteries may include, but are not limited to, energy storage batteries corresponding to the largest or smallest SOC among multiple SOCs.

[0083] In some implementations, the main control device can determine the SOC difference between each phase of the three-phase energy storage battery module of the energy storage unit. If the target phase SOC difference is greater than or equal to a preset threshold, the energy storage battery module with the first phase SOC corresponding to the target phase SOC difference is identified as the first phase energy storage battery module, and the energy storage battery module with the second phase SOC corresponding to the target phase SOC difference is identified as the second phase energy storage battery module. If the first phase SOC is greater than the second phase SOC, the energy storage battery module with the larger phase SOC corresponding to the target phase SOC difference is identified as the first energy storage battery module, and the energy storage battery module with the smaller phase SOC corresponding to the target phase SOC difference is identified as the second energy storage battery module. This can improve the charging success rate of the first phase energy storage battery module charging the second phase energy storage battery module, and is beneficial to improving the control success rate of equalizing the SOC of the three-phase energy storage battery modules.

[0084] The preset threshold can be used to characterize the minimum inter-phase SOC difference of the three-phase SOC imbalance of the three-phase energy storage battery module. The preset threshold may include, but is not limited to, the inter-phase SOC difference set by the user, or the inter-phase SOC difference automatically generated by the main control device based on the control process of balancing the SOC of the three-phase energy storage battery module multiple times.

[0085] As an example, the preset threshold may include, but is not limited to, any one of 10%, 20%, 8%, or 15%.

[0086] Step 130: When the target phase SOC difference is greater than or equal to a preset threshold, control the first phase energy storage battery module corresponding to the target phase SOC difference to charge the second phase energy storage battery module corresponding to the target phase SOC difference until the target phase SOC difference is less than the preset threshold.

[0087] In this embodiment, when the target phase-to-phase SOC difference is greater than or equal to a preset threshold, the main control device can control the first phase energy storage battery module corresponding to the target phase-to-phase SOC difference to charge the second phase energy storage battery module corresponding to the target phase-to-phase SOC difference until the target phase-to-phase SOC difference is less than the preset threshold. When the phase-to-phase SOC difference of the three-phase energy storage battery modules of the energy storage unit is large, the first phase energy storage battery module corresponding to the larger phase-to-phase SOC difference can be controlled to charge the second phase energy storage battery module until the three-phase SOC of the three-phase energy storage battery modules reaches equilibrium. This can reduce the problem of overcharging or over-discharging of the three-phase energy storage battery modules and help improve the service life of the energy storage unit.

[0088] The target phase-to-phase SOC difference may include at least one of the phase-to-phase SOC differences.

[0089] In some implementations, when the target phase-to-phase SOC difference is greater than or equal to a preset threshold, the main control device can control the first phase energy storage battery module corresponding to the target phase-to-phase SOC difference to charge the second phase energy storage battery module corresponding to the target phase-to-phase SOC difference until the target phase-to-phase SOC difference is less than the preset threshold. When the phase-to-phase SOC difference is less than the preset threshold, the main control device controls the energy storage unit to switch to a hot standby state. When the three-phase SOC of the three-phase energy storage battery modules of the energy storage unit is balanced, the main control device controls the energy storage unit to switch to a hot standby state with operating conditions so that the energy storage unit can operate according to the user's scheduling instructions. This helps to improve the user experience during the process of balancing the SOC of the three-phase energy storage battery modules.

[0090] The hot standby state refers to the state where the three-phase energy storage battery modules of an energy storage unit are ready for operation. When the three-phase energy storage battery modules of an energy storage unit in the hot standby state receive a modulation signal with a non-zero amplitude, the three-phase energy storage battery modules of the energy storage unit can be put into operation.

[0091] In some implementations, the main control device can control the energy storage unit to switch to hot standby mode when the SOC difference between each phase is less than a preset threshold. When the three-phase SOC of the three-phase energy storage battery modules of the energy storage unit is in a balanced state, the main control device can control the energy storage unit to switch to a hot standby mode that meets the operating conditions, so that the energy storage unit can operate according to the user's scheduling instructions. This is beneficial to improving the user experience during the process of balancing the SOC of the three-phase energy storage battery modules.

[0092] The solution provided in this application, when the three-phase energy storage battery modules of the energy storage unit are in operation, determines the SOC difference between each phase of the three-phase energy storage battery modules. If the target inter-phase SOC difference is greater than or equal to a preset threshold, the solution controls the first phase energy storage battery module corresponding to the target inter-phase SOC difference to charge the second phase energy storage battery module corresponding to the target inter-phase SOC difference until the target inter-phase SOC difference is less than the preset threshold. If the inter-phase SOC difference between the three-phase energy storage battery modules of the energy storage unit is large, the solution controls the first phase energy storage battery module corresponding to the larger inter-phase SOC difference to charge the second phase energy storage battery module until the three-phase SOC of the three-phase energy storage battery modules reaches equilibrium. This reduces the problem of overcharging or over-discharging of the three-phase energy storage battery modules and helps to improve the service life of the energy storage unit.

[0093] Please refer to Figure 3, which shows a flowchart of a SOC balancing control method for an energy storage unit according to another embodiment of this application. In a specific embodiment, the SOC balancing control method for an energy storage unit can be applied to the main control device 200 in the energy storage system shown in Figure 1. The process shown in Figure 3 will be described in detail below using the main control device 200 as an example. The SOC balancing control method for an energy storage unit may include the following steps 210 to 250.

[0094] Step 210: With the three-phase energy storage battery module of the energy storage unit in operation, determine the SOC difference between each phase of the three-phase energy storage battery module.

[0095] In this embodiment, step 210 can be referred to the corresponding steps in the previous embodiments, and will not be repeated here.

[0096] Step 230: If the target phase-to-phase SOC difference is greater than or equal to a preset threshold, control the energy storage unit to disconnect its electrical connection with the grid.

[0097] In this embodiment, the energy storage system may further include a power grid, which is connected to the three-phase energy storage battery module of the energy storage unit.

[0098] When the target phase-to-phase SOC difference is greater than or equal to a preset threshold, the main control equipment can control the energy storage unit to disconnect from the grid. The three-phase energy storage battery module can be used to charge and discharge the grid. Controlling the energy storage unit to disconnect from the grid helps reduce the interference of the equalization control process on the grid, thereby improving the operational stability of the grid.

[0099] In some implementations, when the target phase-to-phase SOC difference is greater than or equal to a preset threshold, the main control device can obtain the off-peak period of the energy storage unit and, if the unit is currently in an off-peak period, control the energy storage unit to disconnect its electrical connection with the grid. By controlling the energy storage unit to disconnect its electrical connection with the grid during the off-peak period when there is no energy exchange between the energy storage unit and the grid, the interference of the balancing control process on the grid can be further reduced, which is conducive to further improving the operational stability of the grid.

[0100] The off-peak period can be used to characterize the absence of energy exchange between the energy storage unit and the power grid. For example, the off-peak period may include, but is not limited to, the period from 0:00 to 6:00, or the period from 2:00 to 5:00.

[0101] Step 250: With the energy storage unit disconnected from the grid, control the first phase energy storage battery module to charge the second phase energy storage battery module.

[0102] In this embodiment, when the main control device controls the energy storage unit to disconnect from the power grid, it can control the first phase energy storage battery module to charge the second phase energy storage battery module until the target phase SOC difference is less than a preset threshold. When the energy storage unit is disconnected from the power grid, the SOC of the three-phase energy storage battery modules can be balanced, which can reduce the interference of the balancing control process on the power grid and help improve the operation stability of the power grid.

[0103] In one application scenario, as shown in Figure 4, the energy storage unit may include a three-phase energy storage battery module, which consists of an A-phase energy storage battery module, a B-phase energy storage battery module, and a C-phase energy storage battery module. Each of the A-phase, B-phase, and C-phase energy storage battery modules may include 29 energy storage batteries connected in series.

[0104] The A-phase energy storage battery module is connected to the first disconnecting switch (B1) and the first grid-connected reactor (L). b1 The A-phase busbar of the three-phase busbar of the power grid is connected to the B-phase energy storage battery module via the second disconnecting switch (B2) and the second grid-connected reactor (L). b2 The B-phase busbar of the three-phase busbar of the power grid is connected to the C-phase energy storage battery module via the third disconnecting switch (B3) and the third grid-connected reactor (L). b3 The C-phase busbar is connected to the three-phase busbar of the power grid.

[0105] Phase A energy storage battery module is connected to Phase B energy storage battery module through the first load switch (K1), and Phase C energy storage battery module is connected to Phase B energy storage battery module through the second load switch (K2).

[0106] Phase A energy storage battery module is connected to the first metal oxide arrester (MOA1), phase B energy storage battery module is connected to the second metal oxide arrester (MOA2), phase C energy storage battery module is connected to the third metal oxide arrester (MOA3), and phase A, phase B, and phase C energy storage battery modules are all connected to the fourth metal oxide arrester (MOA4).

[0107] Phase A busbar is connected to the fifth metal oxide surge arrester (MOA5), Phase B busbar is connected to the sixth metal oxide surge arrester (MOA6), and Phase C busbar is connected to the seventh metal oxide surge arrester (MOA7).

[0108] Based on the energy storage unit shown in Figure 4, as shown in Figure 5, the SOC equalization control method for the energy storage unit can be implemented in steps 310 to 370.

[0109] Step 310: Collect the three-phase SOC of the three-phase energy storage battery module of the energy storage unit and determine whether the three-phase SOC is balanced.

[0110] Specifically, the main control equipment can collect the SOC of phase A of the phase A energy storage battery module, the SOC of phase B of the phase B energy storage battery module, and the SOC of phase C of the phase C energy storage battery module. Based on the SOC of phase A, phase B, and phase C, it can calculate the SOC difference between each phase of the phase A, phase B, and phase C energy storage battery modules, and determine whether the SOC of the three phases is balanced based on the SOC difference between each phase.

[0111] If there is a target inter-phase SOC difference greater than or equal to a preset threshold among the inter-phase SOC differences, the three-phase SOC is determined to be unbalanced; if there is no target inter-phase SOC difference greater than or equal to a preset threshold among the inter-phase SOC differences, the three-phase SOC is determined to be balanced.

[0112] Step 330: If it is determined that the three-phase SOC is unbalanced and the current time is the off period of the energy storage unit, control B1, B2 and B3 to be in the open state and control K1 and K2 to be in the closed state.

[0113] Step 350: Identify the first phase energy storage battery module and the second phase energy storage battery module, and control the first phase energy storage battery module to charge the second phase energy storage battery module until the three phases are in equilibrium.

[0114] Specifically, the main control device can identify the first phase energy storage battery module corresponding to the first phase SOC of the target phase-to-phase SOC difference as the first phase energy storage battery module, and identify the first phase energy storage battery module corresponding to the second phase SOC of the target phase-to-phase SOC difference as the second phase energy storage battery module, and control the first phase energy storage battery module to charge the second phase energy storage battery module until the three phase SOCs are balanced.

[0115] The SOC of the first phase is greater than that of the second phase.

[0116] Step 370: Control K1 and K2 to be in the open state, and control B1, B2 and B3 to be in the closed state.

[0117] The solution provided in this embodiment determines the SOC difference between each phase of the three-phase energy storage battery module when the energy storage unit is in operation. If the target inter-phase SOC difference is greater than or equal to a preset threshold, the energy storage unit is disconnected from the grid. While the energy storage unit is disconnected from the grid, the first-phase energy storage battery module charges the second-phase energy storage battery module until the target inter-phase SOC difference is less than the preset threshold. If the inter-phase SOC difference between the three-phase energy storage battery modules is large, the first-phase energy storage battery module corresponding to the larger inter-phase SOC difference charges the second-phase energy storage battery module until the three-phase SOC of the three-phase energy storage battery modules reaches equilibrium. This reduces the risk of overcharging or over-discharging of the three-phase energy storage battery modules and helps improve the service life of the energy storage unit.

[0118] Furthermore, by controlling the disconnection of the energy storage unit from the grid, the SOC of the three-phase energy storage battery module can be balanced, which can reduce the interference of the balancing control process on the grid and improve the operational stability of the grid.

[0119] Please refer to Figure 6, which illustrates a SOC balancing control device 400 for an energy storage unit according to an embodiment of this application. In a specific embodiment, the SOC balancing control device 400 can be applied to the main control device 200 in the energy storage system shown in Figure 1. The SOC balancing control device 400 shown in Figure 6 will be described in detail below using the main control device 200 as an example. The SOC balancing control device 400 may include a difference determination module 410 and a charging control module 430.

[0120] The difference determination module 410 can be used to determine the SOC difference between each phase of the three-phase energy storage battery module when the three-phase energy storage battery module of the energy storage unit is in operation; the charging control module 430 can be used to control the first phase energy storage battery module corresponding to the target phase SOC difference to charge the second phase energy storage battery module corresponding to the target phase SOC difference until the target phase SOC difference is less than the preset threshold when the target phase SOC difference is greater than or equal to a preset threshold. The target phase SOC difference includes at least one SOC difference among the phase SOC differences.

[0121] In some implementations, the energy storage unit SOC balancing control device 400 may also include a disconnection control module.

[0122] The disconnection control module can be used by the charging control module 430 to control the first phase energy storage battery module corresponding to the target phase SOC difference to charge the second phase energy storage battery module corresponding to the target phase SOC difference, and control the energy storage unit to disconnect its electrical connection with the grid.

[0123] In some implementations, the charging control module 430 may include a first control unit.

[0124] The first control unit can be used to control the first phase energy storage battery module to charge the second phase energy storage battery module when the energy storage unit is disconnected from the grid.

[0125] In some embodiments, a load switch may be provided between the first phase energy storage battery module and the second phase energy storage battery module, and the energy storage unit SOC balancing control device 400 may also include a first switching control module.

[0126] The first switching control module can be used by the first control unit to control the load switch to switch from the open state to the closed state before the first phase energy storage battery module charges the second phase energy storage battery module.

[0127] In some implementations, the first control unit may include a control subunit.

[0128] The control subunit can be used to control the first phase energy storage battery module to charge the second phase energy storage battery module when the load switch is in the closed state.

[0129] In some implementations, the energy storage unit SOC balancing control device 400 may also include an acquisition module.

[0130] The acquisition module can be used to acquire the off-peak period of the energy storage unit before the disconnection control module controls the energy storage unit to disconnect from the grid. The off-peak period can be used to characterize the absence of energy exchange between the grid and the energy storage unit.

[0131] In some implementations, the disconnection control module may include a second control unit.

[0132] The second control unit can be used to control the energy storage unit to disconnect its electrical connection with the grid when it is currently in a downtime period.

[0133] In some embodiments, the energy storage unit SOC balancing control device 400 may further include a first battery determination module and a second battery determination module.

[0134] The first battery determination module can be used by the charging control module 430 to determine the first phase energy storage battery module corresponding to the target phase SOC difference as the first phase energy storage battery module before the first phase energy storage battery module corresponding to the target phase SOC difference charges the second phase energy storage battery module corresponding to the target phase SOC difference; the second determination module can be used to determine the first phase energy storage battery module corresponding to the target phase SOC difference as the second phase energy storage battery module, and the first phase SOC can be greater than the second phase SOC.

[0135] In some implementations, the difference determination module 410 may include a first determination unit and a second determination unit.

[0136] The first determining unit can be used to determine the three-phase SOC of the three-phase energy storage battery module when the three-phase energy storage battery module of the energy storage unit is in operation, and each phase SOC can correspond to one phase energy storage battery module; the second determining unit can be used to determine the SOC difference between any two phases of the three-phase SOC, and obtain the SOC difference between each phase.

[0137] In some implementations, the first determining unit may include an acquiring subunit and a determining subunit.

[0138] The acquisition subunit can be used to acquire multiple SOCs of multiple energy storage batteries in each phase of the energy storage battery module when the three-phase energy storage battery module of the energy storage unit is in operation, with each SOC corresponding to one energy storage battery; the determination subunit can be used to determine one phase SOC based on the multiple SOCs of each phase energy storage battery module to obtain the three-phase SOC.

[0139] In some implementations, the energy storage unit SOC balancing control device 400 may also include a second switching control module.

[0140] The second switching control module can be used to control the energy storage unit to switch to hot standby mode when the SOC difference between each phase is less than a preset threshold.

[0141] The solution provided in this embodiment determines the SOC difference between each phase of the three-phase energy storage battery module when the three-phase energy storage battery module is in operation. If the target inter-phase SOC difference is greater than or equal to a preset threshold, the first phase energy storage battery module corresponding to the target inter-phase SOC difference charges the second phase energy storage battery module corresponding to the target inter-phase SOC difference until the target inter-phase SOC difference is less than the preset threshold. If the inter-phase SOC difference of the three-phase energy storage battery module is large, the first phase energy storage battery module corresponding to the larger inter-phase SOC difference charges the second phase energy storage battery module until the three-phase SOC of the three-phase energy storage battery module reaches equilibrium. This can reduce the problem of overcharging or over-discharging of the three-phase energy storage battery module and help improve the service life of the energy storage unit.

[0142] It should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For device embodiments, since they are basically similar to method embodiments, the description is relatively simple; relevant parts can be referred to in the descriptions of the method embodiments. Any processing method described in the method embodiments can be implemented in the device embodiments through corresponding processing modules, and will not be elaborated upon further in the device embodiments.

[0143] Furthermore, the functional modules in the various embodiments of this application can be integrated into one processing module, or each module can exist physically separately, or two or more modules can be integrated into one module. The integrated modules described above can be implemented in hardware or as software functional modules.

[0144] Please refer to Figure 7, which shows a functional block diagram of an energy storage system 500 provided in an embodiment of this application. The energy storage system 500 may include one or more of the following components: a memory 510, a processor 520, and one or more application programs. One or more application programs may be stored in the memory 510 and configured to be executed by one or more processors 520. One or more application programs are configured to perform the methods as described in the foregoing method embodiments.

[0145] The memory 510 may include random access memory (RAM) or read-only memory (ROM). The memory 510 may be used to store instructions, programs, code, code sets, or instruction sets. The memory 510 may include a program storage area and a data storage area. The program storage area may store instructions for implementing an operating system, instructions for implementing at least one function (such as determining the SOC difference between phases, controlling charging, controlling the disconnection of electrical connections, obtaining idle time, determining the first phase energy storage battery module, determining the second phase energy storage battery module, determining the three-phase SOC, determining the SOC difference between a phase, obtaining the SOC difference between phases, obtaining multiple SOCs, determining the SOC of a phase, obtaining the three-phase SOC, and controlling the switch to hot standby state, etc.), and instructions for implementing the various method embodiments described below. The storage data area can also store data created by the energy storage system 500 during use (such as energy storage units, three-phase energy storage battery modules, SOC differences between phases, target SOC differences between phases, preset thresholds, first phase energy storage battery modules, second phase energy storage battery modules, power grid, electrical connections, off-peak periods, current time, first phase SOC, second phase SOC, first phase SOC greater than second phase SOC, three-phase SOC, multiple energy storage batteries, multiple SOCs, and hot standby status).

[0146] Processor 520 may include one or more processing cores. Processor 520 connects to various parts of the energy storage system 500 using various interfaces and lines, and performs various functions and processes data of the energy storage system 500 by running or executing instructions, programs, code sets, or instruction sets stored in memory 510, and by calling data stored in memory 510. Optionally, processor 520 may be implemented using at least one hardware form of Digital Signal Processing (DSP), Field-Programmable Gate Array (FPGA), or Programmable Logic Array (PLA). Processor 520 may integrate one or a combination of several of the following: Central Processing Unit (CPU), Graphics Processing Unit (GPU), and modem. The CPU primarily handles the operating system, user interface, and applications; the GPU is responsible for rendering and drawing the displayed content; and the modem handles wireless communication. It is understood that the modem may also not be integrated into processor 520 and may be implemented separately using a communication chip.

[0147] Please refer to Figure 8, which shows a structural block diagram of a computer-readable storage medium provided in an embodiment of this application. The computer-readable storage medium 600 stores program code 610, which can be called by a processor to execute the methods described in the above method embodiments.

[0148] The computer-readable storage medium 600 may be an electronic memory such as flash memory, EEPROM (Electrically Erasable Programmable Read-Only Memory), EPROM, hard disk, or ROM. Optionally, the computer-readable storage medium 600 includes a non-transitory computer-readable storage medium. The computer-readable storage medium 600 has storage space for program code 610 that performs any of the method steps described above. This program code can be read from or written to one or more computer program products. The program code 610 may, for example, be compressed in a suitable form.

[0149] Please refer to Figure 9, which shows a structural block diagram of a computer program product 700 provided in an embodiment of this application. The computer program product 700 includes a computer program / instructions 710, which is stored in a computer-readable storage medium of a computer device. When the computer program product 700 runs on the computer device, the processor of the computer device reads the computer program / instructions 710 from the computer-readable storage medium, and executes the computer program / instructions 710, causing the computer device to perform the methods described in the above method embodiments.

[0150] The solution provided in this embodiment determines the SOC difference between each phase of the three-phase energy storage battery module when the three-phase energy storage battery module is in operation. If the target inter-phase SOC difference is greater than or equal to a preset threshold, the first phase energy storage battery module corresponding to the target inter-phase SOC difference charges the second phase energy storage battery module corresponding to the target inter-phase SOC difference until the target inter-phase SOC difference is less than the preset threshold. If the inter-phase SOC difference of the three-phase energy storage battery module is large, the first phase energy storage battery module corresponding to the larger inter-phase SOC difference charges the second phase energy storage battery module until the three-phase SOC of the three-phase energy storage battery module reaches equilibrium. This can reduce the problem of overcharging or over-discharging of the three-phase energy storage battery module and help improve the service life of the energy storage unit.

[0151] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A method for SOC (State of Charge) equalization control of an energy storage unit, wherein, include: When the three-phase energy storage battery module of the energy storage unit is in operation, determine the SOC difference between each phase of the three-phase energy storage battery module; When the target phase-to-phase SOC difference is greater than or equal to a preset threshold, the first phase energy storage battery module corresponding to the target phase-to-phase SOC difference is controlled to charge the second phase energy storage battery module corresponding to the target phase-to-phase SOC difference until the target phase-to-phase SOC difference is less than the preset threshold. The target phase-to-phase SOC difference includes at least one of the phase-to-phase SOC differences.

2. The SOC equalization control method for energy storage units according to claim 1, wherein, Before the first phase energy storage battery module corresponding to the target phase-to-phase SOC difference charges the second phase energy storage battery module corresponding to the target phase-to-phase SOC difference, the energy storage unit SOC equalization control method further includes: Control the energy storage unit to disconnect its electrical connection from the power grid; The process of controlling the first phase energy storage battery module corresponding to the target inter-phase SOC difference to charge the second phase energy storage battery module corresponding to the target inter-phase SOC difference includes: When the energy storage unit is disconnected from the power grid, the first phase energy storage battery module is controlled to charge the second phase energy storage battery module.

3. The SOC equalization control method for energy storage units according to claim 2, wherein, A load switch is provided between the first phase energy storage battery module and the second phase energy storage battery module. Before controlling the first phase energy storage battery module to charge the second phase energy storage battery module, the energy storage unit SOC balancing control method further includes: Control the load switch to switch from the open state to the closed state; The step of controlling the first phase energy storage battery module to charge the second phase energy storage battery module includes: When the load switch is in the closed state, the first phase energy storage battery module is controlled to charge the second phase energy storage battery module.

4. The SOC equalization control method for energy storage units according to claim 2 or 3, wherein, Before disconnecting the energy storage unit from the power grid, the SOC balancing control method for the energy storage unit further includes: Obtain the off-peak period of the energy storage unit, wherein the off-peak period is used to characterize the absence of energy exchange between the power grid and the energy storage unit; The control of disconnecting the energy storage unit from the power grid includes: When the current time is in the off-peak period, the energy storage unit is controlled to disconnect its electrical connection with the power grid.

5. The SOC equalization control method for energy storage units according to claim 4, wherein, The gap period is used to characterize the absence of energy exchange between the energy storage unit and the power grid.

6. The SOC equalization control method for energy storage units according to any one of claims 1 to 5, wherein, Before the first phase energy storage battery module corresponding to the target phase-to-phase SOC difference charges the second phase energy storage battery module corresponding to the target phase-to-phase SOC difference, the energy storage unit SOC equalization control method further includes: The energy storage battery module corresponding to the first phase SOC of the target phase SOC difference is determined as the first phase energy storage battery module; The energy storage battery module whose second phase SOC corresponds to the target phase SOC difference is determined as the second phase energy storage battery module, where the first phase SOC is greater than the second phase SOC.

7. The SOC equalization control method for energy storage units according to claim 6, wherein, The SOC of the first phase is greater than the SOC of the second phase.

8. The SOC equalization control method for energy storage units according to any one of claims 1 to 7, wherein, The determination of the SOC difference between each phase of the three-phase energy storage battery module when the three-phase energy storage battery module is in operation includes: When the three-phase energy storage battery module of the energy storage unit is in operation, the three-phase SOC of the three-phase energy storage battery module is determined, and each phase SOC corresponds to one phase energy storage battery module. The SOC difference between any two phases is determined based on the SOC of the three phases, thus obtaining the SOC difference between each phase.

9. The SOC equalization control method for energy storage units according to claim 8, wherein, Determining the three-phase SOC of the three-phase energy storage battery module when it is in operation includes: When the three-phase energy storage battery modules of the energy storage unit are in operation, obtain multiple SOCs of multiple energy storage batteries in each phase energy storage battery module, with each SOC corresponding to one energy storage battery. The three-phase SOC is obtained by determining one phase SOC based on the multiple SOCs of each phase energy storage battery module.

10. The SOC equalization control method for energy storage units according to claim 9, wherein, The step of determining the SOC of one phase based on the plurality of SOCs of each phase energy storage battery module includes: Calculate the average SOC of multiple energy storage batteries in each phase energy storage battery module to obtain the average SOC. The average SOC is determined as the SOC of one phase.

11. The SOC equalization control method for energy storage units according to claim 9, wherein, The step of determining the SOC of one phase based on the plurality of SOCs of each phase energy storage battery module includes: Remove the SOC corresponding to the redundant energy storage battery in the multiple energy storage batteries of each phase energy storage battery module from the multiple SOCs to obtain the remaining SOC; Calculate the average value of the remaining SOC to obtain the average SOC value; The average SOC is determined as the SOC of one phase.

12. The SOC equalization control method for energy storage units according to claim 9, wherein, Each phase energy storage battery module consists of one energy storage battery. Determining the three-phase SOC of the three-phase energy storage battery module when it is in operation includes: When the three-phase energy storage battery modules of the energy storage unit are in operation, the SOC of one energy storage battery in each phase energy storage battery module is obtained; The SOC of one energy storage battery is determined as the SOC of one phase of the energy storage battery module, thus obtaining the three-phase SOC.

13. The SOC equalization control method for energy storage units according to any one of claims 1 to 12, wherein, Also includes: If the SOC difference between each phase is less than the preset threshold, the energy storage unit is controlled to switch to hot standby mode.

14. The SOC equalization control method for energy storage units according to any one of claims 1 to 12, wherein, When the target inter-phase SOC difference is greater than or equal to a preset threshold, the method of controlling the first phase energy storage battery module corresponding to the target inter-phase SOC difference to charge the second phase energy storage battery module corresponding to the target inter-phase SOC difference, until the target inter-phase SOC difference is less than the preset threshold, further includes: Control the energy storage unit to switch to hot standby mode.

15. The SOC equalization control method for energy storage units according to any one of claims 1 to 14, wherein, Also includes: When the SOC difference between each phase is less than the preset threshold, the energy storage unit is controlled to switch from the operating state to the hot standby state.

16. A state-of-the-art (SOC) balancing control device for an energy storage unit, wherein, include: The difference determination module is used to determine the SOC difference between each phase of the three-phase energy storage battery module when the three-phase energy storage battery module of the energy storage unit is in operation. The charging control module is used to control the first phase energy storage battery module corresponding to the target phase SOC difference to charge the second phase energy storage battery module corresponding to the target phase SOC difference when the target phase SOC difference is greater than or equal to a preset threshold, until the target phase SOC difference is less than the preset threshold. The target phase SOC difference includes at least one of the phase SOC differences.

17. The energy storage unit SOC balancing control device according to claim 16, wherein, The energy storage unit's SOC balancing control device also includes a disconnection control module, and the charging control module may include a first control unit. The disconnection control module is used to control the energy storage unit to disconnect its electrical connection with the grid before the charging control module controls the first phase energy storage battery module corresponding to the target phase SOC difference to charge the second phase energy storage battery module corresponding to the target phase SOC difference. The first control unit is configured to control the first phase energy storage battery module to charge the second phase energy storage battery module when the energy storage unit is disconnected from the power grid.

18. The energy storage unit SOC balancing control device according to claim 17, wherein, The energy storage unit SOC equalization control device also includes an acquisition module, and the disconnection control module includes a second control unit; The acquisition module is used to acquire the off-time of the energy storage unit before the disconnection control module controls the energy storage unit to disconnect from the power grid. The off-time is used to characterize that there is no energy exchange between the power grid and the energy storage unit. The second control unit is used to control the energy storage unit to disconnect its electrical connection with the power grid when the current time is in the off-peak period.

19. An energy storage system, wherein, include: Memory; One or more processors are coupled to the memory; One or more applications, wherein the one or more applications are stored in the memory and configured to be executed by the one or more processors, and the one or more applications are configured to perform the energy storage unit SOC equalization control method as described in any one of claims 1 to 15.

20. A computer-readable storage medium, wherein, The computer-readable storage medium stores program code, which can be called by a processor to execute the energy storage unit SOC equalization control method as described in any one of claims 1 to 15.

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