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WO-2026091624-A1 - ENERGY STORAGE UNIT SOC BALANCE CONTROL METHOD AND APPARATUS THEREOF, ENERGY STORAGE SYSTEM, AND MEDIUM

WO2026091624A1WO 2026091624 A1WO2026091624 A1WO 2026091624A1WO-2026091624-A1

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.

Inventors

  • LIU, Youwei
  • CHEN, XIAOBO

Assignees

  • 宁德时代新能源科技股份有限公司

Dates

Publication Date
20260507
Application Date
20250630
Priority Date
20241031

Claims (20)

  1. A method for SOC (State of Charge) balancing control of an energy storage unit, comprising: 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. According to the SOC equalization control method for energy storage units as described in claim 1, before 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, 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. According to the SOC balancing control method of the energy storage unit as described in claim 2, 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 SOC balancing control method of the energy storage unit 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. According to claim 2 or 3, the SOC balancing control method for an energy storage unit, before controlling the energy storage unit to disconnect from the power grid, 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. According to the SOC balancing control method for energy storage units as described in claim 4, the off-peak period is used to characterize the absence of energy exchange between the energy storage unit and the power grid.
  6. According to any one of claims 1 to 5, the energy storage unit SOC equalization control method further includes, 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. According to the energy storage unit SOC equalization control method of claim 6, the SOC of the first phase is greater than the SOC of the second phase.
  8. The SOC equalization control method for an energy storage unit according to any one of claims 1 to 7, wherein determining 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 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. According to the SOC balancing control method for energy storage units as described in claim 8, wherein determining 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 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. According to the SOC equalization control method for energy storage units as described in claim 9, wherein 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. According to the SOC equalization control method for energy storage units as described in claim 9, wherein 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. According to the SOC equalization control method for energy storage units as described in claim 9, each phase energy storage battery module consists of one energy storage battery, and determining 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 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 energy storage unit SOC equalization control method according to any one of claims 1 to 12, further comprising: 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 energy storage unit SOC equalization control method according to any one of claims 1 to 12, wherein, when the target phase-to-phase SOC difference is greater than or equal to a preset threshold, controlling 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, further includes: Control the energy storage unit to switch to hot standby mode.
  15. The energy storage unit SOC equalization control method according to any one of claims 1 to 14, further comprising: 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-charge (SOC) balancing control device for an energy storage unit, comprising: 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. According to the energy storage unit SOC balancing control device of claim 16, the energy storage unit SOC balancing control device further 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. According to the energy storage unit SOC balancing control device of claim 17, the energy storage unit SOC balancing control device further 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, comprising: 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 that 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.

Description

Energy storage unit SOC equalization control method and device, energy storage system and medium 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 This application belongs to the field of energy storage technology, and in particular relates to a SOC equalization control method and device for energy storage units, as well as an energy storage system and medium. Background Technology 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. 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. Application content 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 The technical solution adopted in the embodiments of this application is: In a first aspect, embodiments of this application provide a method for SOC (State of Charge) balancing control of an energy storage unit, including: 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 SOC difference among the phase-to-phase SOC differences. 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: Disconnect the energy storage unit from the power grid. 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: 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. 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: Control the load switch to switch from the open state to the closed state; Controlling the first-phase energy storage battery module to charge the second-phase energy storage battery module includes: When the load switch is closed, the first phase energy storage battery module is controlled to charge the second phase energy storage battery module. 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: 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. Disconnecting the energy storage unit from the power grid includes: In the event of a current off-peak period, the energy storage unit is disconnected from the power grid. 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: 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. 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 m