Energy storage system and battery management system

Abstract

The present application relates to the technical field of energy storage systems, and discloses an energy storage system and a battery management system. The energy storage system comprises battery packs, a battery management system, and a balanced power supply circuit. Each battery pack comprises a plurality of batteries. The battery management system comprises a self-balancing circuit used for performing voltage balancing on the plurality of batteries. An input end of the balanced power supply circuit is electrically connected to the battery packs. The balanced power supply circuit is used for drawing power from the battery packs, convert the power drawn from the battery packs into supply power, and then output same to the battery management system, so as to control the self-balancing circuit to perform voltage balancing on the plurality of batteries. The present application aims to provide an energy storage system capable of shortening the grid connection test cycle.

Description

Energy storage systems and battery management systems

[0001] Related applications

[0002] This application claims priority to Chinese patent application No. 202510051574.X, filed on January 13, 2025, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the field of energy storage system technology, and in particular to an energy storage system and a battery management system. Background Technology

[0004] In existing energy storage systems, it takes 3 to 9 months from product launch to customer arrival. During this period, the energy storage system is in a power-off state and is affected by the difference in cell self-discharge. By the time the energy storage system is connected to the grid for testing, voltage differences have already appeared between the power boxes and between the energy storage battery clusters. This difference will affect the available power of the system and affect the customer's grid connection acceptance.

[0005] Utility Model Content

[0006] The main objective of this application is to propose an energy storage system and a battery management system, with the aim of providing an energy storage system that can shorten the grid connection test cycle.

[0007] To achieve the above objectives, in a first aspect, this application proposes an energy storage system, which includes a battery pack, a battery management system, and a voltage equalization circuit. The battery pack includes multiple batteries. The battery management system includes a self-balancing circuit for voltage equalization of the multiple batteries. The input terminal of the voltage equalization circuit is electrically connected to the battery pack. The voltage equalization circuit draws power from the battery pack and converts the electrical energy obtained from the battery pack into power supply energy before outputting it to the battery management system, thereby controlling the self-balancing circuit to perform voltage equalization on the multiple batteries.

[0008] Understandably, the self-balancing circuit is used to balance the voltage of multiple batteries. This balancing power supply circuit can draw power from multiple batteries in the battery pack and convert this power into power that is compatible with the self-balancing circuit in the battery management system, allowing the self-balancing circuit to start balancing operations directly. However, in some exemplary technologies, an external auxiliary power source is manually connected and external balancing is performed before grid connection testing, resulting in a lengthy grid connection testing cycle for the energy storage system. The energy storage system in this application, however, allows the balancing action, which originally needed to be performed after connecting the external auxiliary power source in the exemplary technologies, to be carried out in advance during the external auxiliary power source preparation stage, thereby separating the balancing process from the grid connection test and ultimately effectively shortening the entire grid connection testing cycle.

[0009] In one embodiment, the equalization power supply circuit includes an equalization power extraction module and a switching module; the input terminal of the equalization power extraction module is connected to the battery pack, and the equalization power extraction module is used to extract power from the battery pack and convert the electrical energy obtained from the battery pack into power supply energy for output; the switching module is connected in series between the equalization power extraction module and the power supply terminal of the battery management system, and the switching module is used to close when triggered to control the electrical connection between the equalization power extraction module and the battery management system and to supply power to the battery management system.

[0010] Understandably, the balancing power extraction module in this balancing power supply circuit has its input connected to the multiple batteries, and its output connected to the self-balancing circuit via the switching module. Thus, when the energy storage product arrives at the customer's location, the operator can manually close the power extraction switch in the switching module, and the balancing power extraction module will then draw high-voltage electricity from the batteries as the power supply for the self-balancing circuit. In other words, the balancing action, which originally needed to be performed concurrently with grid connection testing after connecting to an external auxiliary power source, can now be initiated during the external auxiliary power source preparation stage, thereby separating the balancing process from the grid connection test and effectively shortening the entire grid connection test cycle.

[0011] In one embodiment, the switching module includes a mechanical switch that is closed when triggered to control the electrical connection between the power-taking module and the battery management system, and to supply power to the battery management system.

[0012] Understandably, the switch module employs a mechanical switch design, providing a simple and reliable manual control mechanism and reducing potential points of technical failure. Furthermore, by manually operating the mechanical switch, users can intuitively control the start-up timing of the energy storage system and freely activate the internal balancing process. This gives the switch module the advantages of simplicity and convenience.

[0013] In one embodiment, the switch module includes an electronically controlled switch and a communication component, the electronically controlled switch and the communication component being connected; the communication component is used to receive a trigger signal, and the electronically controlled switch closes in response to the trigger signal to control the electrical connection between the power-taking module and the battery management system, and to supply power to the battery management system.

[0014] Understandably, the communication component allows users to send trigger signals via various means (such as mobile applications, computer software, or on-site control panels) without physical contact with the mechanical switch, thus enabling remote initiation of the balancing process. The electronically controlled switch automatically closes upon receiving the trigger signal, ensuring electrical connection between the power supply module and the self-balancing circuit, and supplying power to the self-balancing circuit. This improves the system's efficiency and safety.

[0015] In one embodiment, the equalization power supply module includes a transformer component connected in series between the battery and the switch module, or the transformer component connected in series with the end of the switch module away from the battery; the transformer component is used to step down the output voltage of the battery so that the output voltage of the battery is adapted to the operating voltage of the self-balancing circuit of the battery management system.

[0016] Understandably, through voltage conversion, the transformer component can adjust the higher voltage provided by the battery to the optimal voltage range suitable for the operation of the self-balancing circuit, avoiding the risk of inefficiency or hardware damage caused by voltage mismatch. More importantly, stable and compatible power supply conditions help improve the speed and accuracy of the self-balancing process, thereby further shortening the grid connection test cycle.

[0017] In one embodiment, the energy storage system further includes a relay assembly connected in series with the output terminal of the battery pack, the relay assembly being used to output the electrical energy of the battery pack when closed; the input terminal of the equalization power extraction module is connected to the path between the battery and the relay assembly.

[0018] Understandably, the input of the equalization power module is connected to the path between the battery and the relay assembly, allowing power to be drawn even when the relay is not closed, thus greatly facilitating the maintenance and commissioning of the energy storage system. In this way, the energy storage system can more efficiently complete battery voltage equalization before grid connection testing.

[0019] In one embodiment, the equalization power supply circuit further includes an auxiliary power supply module. The input terminal of the auxiliary power supply module is used to connect to an external auxiliary power source, and the output terminal of the auxiliary power supply module is connected to a load. The output terminal of the equalization power supply module includes a first output branch and a second output branch. The first output branch is connected to the battery management system, and the second output branch is connected to the load. One of the auxiliary power supply module and the second output branch is used as the power supply for the load.

[0020] Understandably, the balancing power supply circuit incorporates an auxiliary power source module to connect to an external auxiliary power source, with its output connected to the load. The output of the balancing power source module is divided into two branches: the first branch connects to the self-balancing circuit, providing power to it; the other branch connects directly to the load. The auxiliary power source module and the balancing power source module together constitute a flexible power supply scheme, where either one can serve as the power source for the load. Optionally, when an external auxiliary power source is available, the auxiliary power source module can directly power the load, reducing the battery's burden and extending its lifespan; when no external power source is available, the balancing power source module can draw power from the battery, supporting not only the operation of the self-balancing circuit but also continuing to provide power to the load, ensuring uninterrupted system functionality. This allows the energy storage system to maintain efficient operation in various environments.

[0021] In one embodiment, the output terminal of the auxiliary power supply module is also connected to the battery management system; one of the auxiliary power supply module and the equalization power supply module is used as the power supply for the battery management system.

[0022] Understandably, the output of the balancing power supply circuit is connected not only to the load but also directly to the self-balancing circuit, allowing either the auxiliary power source module or the balancing power source module to serve as a power supply for the self-balancing circuit. This enhances the flexibility and reliability of the energy storage system under different operating conditions.

[0023] In one embodiment, the equalization power supply circuit further includes an output control circuit and a signal receiving circuit. The signal receiving circuit is connected to the input terminal of the output control circuit, and the output terminal of the output control circuit is respectively controlled to be connected to the auxiliary power source module and the equalization power source module. The signal receiving circuit is used to receive a trigger signal and output the trigger signal to the output control circuit. The output control circuit is used to control one of the auxiliary power source module and the equalization power source module to be the power supply for the load according to the trigger signal. And / or, the output control circuit is used to control one of the auxiliary power source module and the equalization power source module to be the power supply for the battery management system according to the trigger signal.

[0024] Understandably, through the signal receiving circuit, users can send trigger signals via various means (such as wireless signals, network commands, or local control panels) to achieve remote or automated control. The output control circuit reacts to the trigger signal by switching the power supply path to ensure that the most suitable power source provides power to the load or self-balancing circuit.

[0025] In one embodiment, the auxiliary power supply module includes an auxiliary power switch and an auxiliary power conversion circuit connected in series; the auxiliary power switch is used to close after being triggered to control the auxiliary power supply module to supply power to the load; the auxiliary power conversion circuit is used to perform power conversion on the power input from the external auxiliary power source.

[0026] Understandably, the auxiliary power switch closes upon user triggering to control the auxiliary power module to supply power to the load; while the auxiliary power conversion circuit is responsible for performing necessary conversions on the power input from the external auxiliary power source. This provides a highly flexible and reliable external power management solution, significantly improving the overall performance of the energy storage system and the user experience.

[0027] In one embodiment, the self-balancing circuit includes a detection unit and an equalization unit, the detection unit being connected to the equalization unit; the detection unit is used to detect the voltage signals of the plurality of battery packs and output the voltage signals to the equalization unit; the equalization unit is used to perform voltage equalization on the plurality of battery packs according to the voltage signals, so that the voltage difference of each battery pack is less than a first preset difference.

[0028] Understandably, the detection unit is responsible for monitoring the voltage signals of multiple batteries in real time and transmitting these signals, which characterize the battery's operating status (such as voltage, current, and temperature), to the equalization unit. The equalization unit then performs precise parameter equalization adjustments on each battery based on the received voltage signals, ensuring that the voltage difference between each battery remains within a preset first threshold. This avoids voltage or charge inconsistencies caused by long-term accumulation, effectively extending battery life and improving the performance and reliability of the energy storage system.

[0029] In one embodiment, the energy storage system further includes a controller, which controls the self-balancing circuit to perform balancing operations; the controller controls the self-balancing circuit to detect the voltage of multiple batteries after power-on; and controls the self-balancing circuit to perform balancing operations so that the voltage difference between each battery is less than a first preset difference.

[0030] Understandably, in response to the conduction signal, the automatic closing switch module establishes an electrical connection between the equalization power supply module and the self-balancing circuit, and supplies power to it. Subsequently, the self-balancing circuit immediately detects the voltage of multiple batteries and performs precise equalization adjustments based on real-time data, ensuring that the voltage difference between each battery remains within a preset first threshold. This automated control not only shortens preparation time and improves operational efficiency but also enables the rapid initiation of the self-balancing process without external auxiliary power, pre-emptively performing voltage equalization actions, optimizing the grid connection preparation process, and accelerating grid connection acceptance.

[0031] In one embodiment, the controller is specifically configured to determine that the two batteries are batteries to be balanced when the voltage difference between any two batteries is not less than a first preset value; and to control the self-balancing circuit to perform voltage balancing on the batteries to be balanced so that the voltage difference between the two batteries to be balanced is less than the first preset value.

[0032] Understandably, the system first acquires the voltage of each battery, then automatically identifies cases where the voltage difference between any two batteries is not less than a first preset value, and determines these batteries as those to be balanced. Subsequently, it performs precise balancing on these batteries to ensure that the voltage difference between all batteries remains within a preset threshold. In this way, it can accurately locate batteries that need adjustment, avoid unnecessary balancing operations, improve energy utilization efficiency, and promptly correct minor differences between batteries.

[0033] In one embodiment, the controller is specifically configured to determine the average voltage of each battery as a first preset reference value; if the difference between the voltage of the battery and the first preset reference value is not less than a second preset value, determine the battery as a battery to be balanced; and control the self-balancing circuit to perform voltage balancing on the battery to be balanced, so that the difference between the voltage of the battery to be balanced and the first preset reference value is less than the second preset value.

[0034] Understandably, after the self-balancing circuit is activated, the system first acquires the voltage of each battery and calculates the average of these voltages as a first preset reference value. Next, the system compares the voltage of each battery with this reference value. If the difference is not less than a second preset value, the battery is identified as needing balancing, and the balancing mode is activated to ensure that the difference between its voltage and the reference value ultimately falls below the second preset value. Thus, this average-value-based method not only accurately identifies batteries requiring adjustment, avoiding unnecessary balancing operations on all batteries and improving energy utilization efficiency, but also effectively corrects minor differences between batteries, extending battery life.

[0035] Secondly, this application also provides an energy storage system control method, the energy storage system control method comprising: controlling the self-balancing circuit to detect the voltage of multiple batteries after power-on; controlling the self-balancing circuit to perform balancing operation so that the voltage difference between each battery is less than a first preset difference.

[0036] Understandably, this method improves operational efficiency and can quickly initiate the self-balancing process without external auxiliary power supply, thereby pre-positioning the voltage balancing action, optimizing the grid connection preparation process, and accelerating the grid connection acceptance speed.

[0037] In one embodiment, the equalization power supply circuit includes an equalization power extraction module and an auxiliary power extraction module. The input terminal of the equalization power extraction module is connected to the battery of the energy storage system, and the input terminal of the auxiliary power extraction module is connected to an external auxiliary power source. The output terminals of the equalization power extraction module and the auxiliary power extraction module are respectively connected to the load. The energy storage system control method further includes: acquiring the operating voltage of the load; acquiring the output voltages of the equalization power extraction module and the auxiliary power extraction module; determining a first difference between the operating voltage and the output voltage of the equalization power extraction module, and determining a second difference between the operating voltage and the output voltage of the auxiliary power extraction module; outputting a first power supply signal in response to the first difference being greater than the second difference, and controlling the auxiliary power extraction module to supply power to the load; and outputting a second power supply signal in response to the first difference not being greater than the second difference, and controlling the equalization power extraction module to supply power to the load. Thus, the equalization power extraction module supplies power to the load.

[0038] In one embodiment, the equalization power supply circuit includes an equalization power extraction module and an auxiliary power extraction module. The input terminal of the equalization power extraction module is connected to the battery of the energy storage system, and the input terminal of the auxiliary power extraction module is connected to an external auxiliary power source. The output terminals of the equalization power extraction module and the auxiliary power extraction module are respectively connected to the self-balancing circuit. The energy storage system control method further includes: acquiring the operating voltage of the self-balancing circuit; acquiring the output voltages of the equalization power extraction module and the auxiliary power extraction module; determining a first difference between the operating voltage and the output voltage of the equalization power extraction module, and determining a second difference between the operating voltage and the output voltage of the auxiliary power extraction module; outputting a first power supply signal in response to the first difference being greater than the second difference; and controlling the auxiliary power extraction module to supply power to the self-balancing circuit in response to the first difference being less than the second difference. Thus, when the external auxiliary power source is unavailable, the system can quickly switch to battery power, pre-emptively balancing the voltage, shortening the grid connection testing cycle, accelerating grid connection acceptance, and improving the overall progress and efficiency of the project.

[0039] In one embodiment, controlling the self-balancing circuit to perform balancing operations so that the voltage difference between each battery is less than a first preset difference includes: acquiring the voltage of each battery; determining that two batteries are batteries to be balanced if the voltage difference between any two batteries is not less than the first preset value; and controlling the self-balancing circuit to perform balancing operations on the batteries to be balanced. This allows for precise location of batteries requiring adjustment, avoids unnecessary balancing operations, improves energy utilization efficiency, and promptly corrects minor differences between batteries.

[0040] Thirdly, this application also provides a battery management system applied to an energy storage system, the energy storage system including a battery pack, the battery pack including multiple batteries; the battery management system including: a battery management circuit, a self-balancing circuit, and a voltage equalization power supply circuit; the battery management circuit is used to manage the battery pack; the self-balancing circuit is used to equalize the voltage of the multiple batteries; the input terminal of the voltage equalization power supply circuit is electrically connected to the battery pack, the voltage equalization power supply circuit is used to draw power from the battery pack, and convert the electrical energy obtained from the battery pack into power supply energy and output it to the battery management system, so as to control the self-balancing circuit to equalize the voltage of the multiple batteries.

[0041] It is understood that this battery management system is a commonly used battery management system in energy storage systems, including a battery management circuit for managing the batteries. The self-balancing circuit is used to balance the voltage of multiple batteries. This battery management system can draw power from multiple batteries in the battery pack through the balancing power supply circuit and convert this power into power that is compatible with the self-balancing circuit in the battery management system, allowing the self-balancing circuit to directly begin balancing operations. However, in some exemplary technologies, an external auxiliary power source is manually connected and external balancing is performed before grid connection testing, resulting in a lengthy grid connection testing cycle for the energy storage system. The battery management system in this application can perform this process during the external auxiliary power source preparation stage, effectively shortening the entire grid connection testing cycle.

[0042] In one embodiment, the equalization power supply circuit includes an equalization power extraction module and a switching module; the input terminal of the equalization power extraction module is connected to the battery pack, and the equalization power extraction module is used to extract power from the battery pack and convert the electrical energy obtained from the battery pack into power supply energy for output; the switching module is connected in series between the equalization power extraction module and the power supply terminal of the battery management system, and the switching module is used to close when triggered to control the electrical connection between the equalization power extraction module and the battery management system and to supply power to the battery management system.

[0043] Understandably, the balancing power extraction module in this balancing power supply circuit has its input connected to the multiple batteries, and its output connected to the self-balancing circuit via the switching module. Thus, when the energy storage product arrives at the customer's location, the operator can manually close the power extraction switch in the switching module, and the balancing power extraction module will then draw high-voltage electricity from the batteries as the power supply for the self-balancing circuit. In other words, the balancing action, which originally needed to be performed concurrently with grid connection testing after connecting to an external auxiliary power source, can now be initiated during the external auxiliary power source preparation stage, thereby separating the balancing process from the grid connection test and effectively shortening the entire grid connection test cycle. Attached Figure Description

[0044] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art 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 the structures shown in these drawings without creative effort.

[0045] Figure 1 is a schematic diagram of the first embodiment of the energy storage system provided in this application;

[0046] Figure 2 is a schematic diagram of a second embodiment of the energy storage system provided in this application;

[0047] Figure 3 is a schematic diagram of the third embodiment of the energy storage system provided in this application;

[0048] Figure 4 is a schematic diagram of the fourth embodiment of the energy storage system provided in this application;

[0049] Figure 5 is a circuit diagram of an embodiment of the energy storage system provided in this application;

[0050] Figure 6 is a flowchart of the first embodiment of the energy storage system control method provided in this application;

[0051] Figure 7 is a flowchart of the second embodiment of the energy storage system control method provided in this application;

[0052] Figure 8 is a flowchart of the third embodiment of the energy storage system control method provided in this application;

[0053] Figure 9 is a flowchart of the fourth embodiment of the energy storage system control method provided in this application;

[0054] Figure 10 is a flowchart of the fifth embodiment of the energy storage system control method provided in this application;

[0055] Figure 11 is a flowchart of the sixth embodiment of the energy storage system control method provided in this application.

[0056] Explanation of reference numerals: 10, Energy storage system; 100, Battery pack; 200, Battery management system; 210, Self-balancing circuit; 211, Detection unit; 212, Balancing unit; 300, Balancing power supply circuit; 310, Balancing power extraction module; 320, Switching module; 340, Transformer assembly; 400, Relay assembly; 500, Auxiliary power extraction module.

[0057] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0058] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0059] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0060] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more (including two), unless otherwise explicitly defined.

[0061] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0062] In the description of the embodiments of this application, the term "and / or" is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone.

[0063] It should be noted that step designations such as S100 and S200 are used in this document for the purpose of more clearly and concisely describing the corresponding content, and do not constitute a substantial limitation on the order. In specific implementation, those skilled in the art may execute S200 first and then S100, etc., but these should all be within the protection scope of this application.

[0064] Energy storage systems are systems used to store and output electrical energy. They are widely used in the power industry and renewable energy sectors. Energy storage systems not only balance grid supply and demand fluctuations and improve energy efficiency, but also effectively address the intermittency and instability of power supply. By storing excess energy during periods of low demand and releasing it during peak periods, they help to smooth out peak flows, stabilize grid operation, and reduce reliance on traditional fossil fuel power generation. Furthermore, energy storage systems support the integration of distributed energy resources (such as solar and wind power), ensuring a stable power supply even under adverse weather conditions or at night.

[0065] In existing energy storage systems, the time from product launch to delivery to the customer is lengthy, involving processes such as factory testing, packaging, logistics, and warehousing. This process typically takes 3 to 9 months. This leads to a problem: during this extended transportation and storage period, the energy storage system is powered off, allowing the cells to self-discharge. Because each cell has a different self-discharge rate, even if all cells are initially charged to the same voltage level, inconsistencies in cell charge levels will gradually appear over time. Understandably, these differences in charge levels will cause voltage deviations between cell units, which can become significant, especially after prolonged storage.

[0066] When the energy storage system finally arrives at the client and is ready for grid connection testing, the voltage differences between the power distribution boxes and between the battery clusters are already quite significant. These voltage differences affect the overall performance of the system, particularly the accurate assessment of available power, thus impacting the client's grid connection acceptance. Specifically, voltage inconsistencies may cause some battery cells to reach their charging or discharging limits prematurely, limiting the overall system's usable capacity and increasing the complexity and time cost of grid connection testing.

[0067] However, to address the aforementioned voltage differences, existing technologies involve manually connecting an external auxiliary power source and performing external balancing before grid connection testing. This method results in a lengthy grid connection testing cycle for energy storage systems. After the energy storage system arrives at the client, technicians need to manually connect the external auxiliary power source and then activate external balancing equipment to adjust each battery cluster individually. This process is time-consuming, significantly extending the overall grid connection testing cycle. More importantly, after the external auxiliary power source is connected, the battery management system detects the voltage of multiple batteries. However, because the self-balancing current of the external auxiliary power source is small, external balancing equipment is required for balancing, which also prolongs the balancing process. Therefore, external balancing equipment typically requires a considerable amount of time to complete the balancing of all battery cells, especially in large-scale energy storage systems involving a large number of batteries, further reducing efficiency, extending preparation time, and lengthening grid connection testing time.

[0068] Energy storage systems can include generation-side energy storage systems, consumption-side energy storage systems, and grid-side energy storage systems.

[0069] For generation-side energy storage systems, these systems are primarily used in conjunction with renewable energy generation technologies to form integrated systems. This allows for the smoothing of renewable energy output, reducing wind and solar curtailment, providing system inertia support, and enabling frequency and peak regulation, thereby improving the utilization rate of renewable energy and grid stability. Simultaneously, the energy storage system can store electrical energy during off-peak hours and release it during peak hours, alleviating grid pressure. In some cases, it can be applied to large-scale wind farms, photovoltaic power plants, and hybrid renewable energy power plants (including multiple renewable energy sources such as wind and solar power).

[0070] For energy storage systems on the demand side, these systems are primarily used at the user end to help users achieve peak-valley arbitrage, improve power quality management, and provide emergency backup power. These systems can be applied to various scenarios, from large industrial and commercial users to residential users, and even special scenarios such as communication base stations, UPS backup power, and island microgrids. Large industrial and commercial users can include automobile manufacturing plants, chemical plants, data centers, shopping malls, office buildings, and hotels; residential users can include solar-powered home appliances and smart home systems.

[0071] For grid-side energy storage systems, which are mainly used on the transmission and distribution side, intelligent load management is provided. They can adjust peak load and frequency in a timely manner according to the grid load, thereby improving the grid's flexibility, enhancing its capacity to accommodate loads, and ensuring the safe, stable, and efficient operation of the grid.

[0072] In response, the energy storage system proposed in this application can quickly initiate a self-balancing process before grid connection testing by integrating a power balancing circuit, thereby shortening the preparation time and accelerating the grid connection acceptance speed.

[0073] As shown in Figure 1, this application proposes an energy storage system 10, including a battery pack 100, a battery management system 200, and an equalization power supply circuit. The battery pack 100 includes multiple batteries. The battery management system 200 includes a self-balancing circuit for voltage equalization of the multiple batteries. The input terminal of the equalization power supply circuit is electrically connected to the battery pack 100. The equalization power supply circuit draws power from the battery pack 100, converts the electrical energy obtained from the battery pack 100 into power supply energy, and outputs it to the battery management system 200 to control the self-balancing circuit to perform voltage equalization of the multiple batteries.

[0074] In this embodiment, the energy storage system 10 includes multiple batteries and a self-balancing circuit 210. The self-balancing circuit 210 can be integrated into the battery management system 200 or is itself part of the BMS. The self-balancing circuit 210 is used to balance the multiple batteries to reduce voltage inconsistencies caused by differences in cell self-discharge rates during long-term storage or transportation. During balancing, the self-balancing circuit 210 detects the voltage of each battery, and then identifies and adjusts batteries whose voltage deviates from a preset range, ensuring that the voltage difference between all batteries remains within a minimum range.

[0075] Optionally, the equalization power supply circuit 300 is used in the energy storage system 10. The equalization power supply circuit 300 includes an equalization power extraction module 310 and a switch module 320. The input terminal of the equalization power extraction module 310 is connected to the battery pack 100. The equalization power extraction module 310 is used to extract power from the battery pack 100 and convert the electrical energy obtained from the battery pack 100 into power supply energy before outputting it. The switch module 320 is connected in series between the equalization power extraction module 310 and the power supply terminal of the self-balancing circuit 210. The switch module 320 is used to close when triggered by the user to control the electrical connection between the equalization power extraction module 310 and the self-balancing circuit 210, and to supply power to the battery management system 200. The equalization power supply circuit 300 converts the electrical energy obtained from the battery pack 100 into power supply energy and outputs it to the battery management system 200 to control the self-balancing circuit to perform voltage equalization on multiple batteries.

[0076] In this embodiment, the power balancing module 310 has its input terminal connected to the battery. It is responsible for drawing power from the battery and converting the obtained electrical energy into power suitable for the operation of the self-balancing circuit 210 before outputting it. Optionally, the power balancing module 310 can not only efficiently draw power from the battery but also convert the drawn energy into a stable power supply suitable for the operation of the self-balancing circuit 210. It can be understood that through this power balancing module 310, after the energy storage system 10 arrives at the customer site, it can provide power support for the self-balancing circuit 210, perform pre-voltage balancing, ensure the consistency of battery status, optimize the grid connection preparation process, and accelerate the grid connection acceptance speed.

[0077] Optionally, the power balancing module 310 can dynamically adjust the output power according to the actual needs of the self-balancing circuit 210 to avoid overload or underload. For example, in some cases, the self-balancing circuit 210 may only need to operate at low power. In this case, the power balancing module 310 will automatically reduce the output power to reduce unnecessary energy loss and improve energy efficiency.

[0078] Understandably, in one exemplary technology, manually connecting an external auxiliary power source and performing external balancing before grid connection testing leads to a lengthy grid connection testing cycle for the energy storage system. Specifically, after the energy storage system arrives at the client, technicians need to manually connect the external auxiliary power source and then activate the external balancing equipment to adjust each battery cluster individually, a time-consuming process that significantly extends the entire grid connection testing cycle. However, in this embodiment, the balancing power extraction module 310 directly extracts power from the battery and outputs the battery's energy to the self-balancing circuit 210. This allows the self-balancing circuit 210 to begin balancing operations before the external auxiliary power source is connected, thus shortening the subsequent grid connection testing cycle.

[0079] In this embodiment, as shown in Figure 1, the switch module 320 is connected in series between the power supply terminals of the equalization power supply module 310 and the self-balancing circuit 210. This module can close upon user triggering, establishing an electrical connection between the equalization power supply module 310 and the self-balancing circuit 210, and supplying power to the self-balancing circuit 210. Thus, the user can flexibly control the start time of the equalization process according to actual needs, improving the system's operational flexibility and response speed.

[0080] Optionally, the switch module can be triggered manually or remotely, or a combination of both. Users can trigger the switch module 320 to close by manual operation or remote commands (such as through a mobile application, computer software, or on-site control panel), thus simplifying the operation process and supporting the integration of automated operation and maintenance systems.

[0081] Understandably, without the switch module 320, the self-balancing circuit 210 would be continuously powered, leading to a series of problems and risks. First, continuous power supply could result in unnecessary energy consumption, especially when the energy storage system 10 is in storage or transport mode for extended periods. Continuous energy consumption would accelerate battery self-discharge, shorten battery life, and affect its performance. Second, continuous power supply increases the risk of system failure. For example, without proper monitoring, the self-balancing circuit 210 might continue operating when not needed, leading to overheating or other electrical malfunctions. Furthermore, prolonged power supply could also cause safety issues such as short circuits or overloads, potentially damaging equipment or creating safety hazards. Therefore, with the switch module 320, users can flexibly control the power supply status of the self-balancing circuit 210 according to actual needs, ensuring that the self-balancing circuit 210 is only powered when voltage balancing is required.

[0082] In one feasible embodiment, in a typical outdoor energy storage power station application scenario, the energy storage system 10 arrives at the installation site after a long transportation period. At this time, technicians first manually close the switch module 320 to activate the equalization power extraction module 310. The equalization power extraction module 310 draws power from the battery and converts the battery's high voltage (e.g., 1200V) to a low voltage (e.g., 24V) suitable for the operation of the self-balancing circuit 210 via its built-in DC-DC converter. Simultaneously, the equalization power extraction module 310 dynamically adjusts its output power according to the needs of the self-balancing circuit 210, ensuring efficient self-balancing. In this way, equalization can be performed directly before the external auxiliary power supply is connected, avoiding the disadvantage of having to connect an external auxiliary power supply before starting battery voltage equalization, thereby shortening the grid connection testing cycle.

[0083] As shown in Figure 5, the switch module 320 is specifically the first switch Q1, which is connected in series in the equalization power supply module 310 at the end furthest from the battery.

[0084] In summary, the self-balancing circuit 210 is used to balance the battery voltage of multiple batteries. The equalization power extraction module 310 in this equalization power supply circuit 300 has its input connected to the multiple batteries, and its output connected to the self-balancing circuit 210 via the switch module 320. Thus, when the energy storage product arrives at the customer's location, the operator can manually close the power extraction switch in the switch module 320, and the equalization power extraction module 310 will then draw high-voltage electricity from the batteries as the power supply for the self-balancing circuit 210. In other words, the balancing action, which originally needed to be performed concurrently with grid connection testing after connecting to an external auxiliary power source, can now be carried out during the external auxiliary power source preparation stage, thereby separating the balancing process from the grid connection test and effectively shortening the entire grid connection test cycle.

[0085] Optionally, a separate balancing battery, distinct from the aforementioned energy storage battery, can be incorporated into the energy storage system 10. Introducing a balancing battery reduces the frequency of power extraction from the energy storage battery, especially when high energy output is not required. This helps lower the charging and discharging frequency of the energy storage battery, reducing wear and tear and extending its lifespan.

[0086] In this embodiment, the switch module 320 includes a mechanical switch that closes when triggered to control the electrical connection between the power extraction module and the self-balancing circuit 210, and to supply power to the battery management system 200. It is understood that the mechanical switch design of the switch module 320 provides a simple and reliable manual control mechanism, reducing potential points of technical failure. Furthermore, by manually operating the mechanical switch, the user can intuitively control the start-up timing of the energy storage system 10, and quickly activate the internal balancing process even without an external auxiliary power source. Thus, the switch module 320 possesses the advantages of simplicity and convenience.

[0087] In this embodiment, the switch module 320 includes an electronically controlled switch and a communication component, which are connected. The communication component receives a trigger signal, and the electronically controlled switch closes in response to the trigger signal to control the electrical connection between the power-gathering module and the self-balancing circuit 210, and to supply power to the self-balancing circuit 210. It is understood that the communication component allows users to send trigger signals through various means (such as mobile applications, computer software, or field control panels) without physical contact with the mechanical switch, thereby enabling remote initiation of the balancing process. The electronically controlled switch automatically closes in response to the received trigger signal, ensuring the electrical connection between the power-gathering module and the self-balancing circuit 210, and supplying power to the self-balancing circuit 210. This improves the system's efficiency and safety. Optionally, the design of this electronically controlled switch and communication component can also record each trigger event, aiding in monitoring and troubleshooting, and enhancing the system's reliability and traceability.

[0088] It should be noted that the specific form of the switch module 320 is not limited here, and depends on the user's needs or the application scenario of the energy storage module. For some small or specific applications, mechanical switches may be more suitable; while for large-scale energy storage systems with 10 or more distributed points, the combination of electronic control switches and communication components can better leverage their advantages.

[0089] In one embodiment, as shown in FIG2, the equalization power supply module 310 includes a transformer component 340, which is connected in series between the battery and the switch module 320, or the transformer component 340 is connected in series with the end of the switch module away from the battery; the transformer component 340 is used to step down the output voltage of the battery so that the output voltage of the battery is adapted to the operating voltage of the self-balancing circuit 210 of the battery management system 200.

[0090] Understandably, through voltage conversion, the transformer component 340 can adjust the higher voltage provided by the battery to the optimal voltage range suitable for the operation of the self-balancing circuit 210, avoiding the risk of inefficiency or hardware damage caused by voltage mismatch. More importantly, stable and compatible power supply conditions help improve the speed and accuracy of the self-balancing process, thereby further shortening the grid connection test cycle.

[0091] Optionally, as shown in Figures 2 and 5, the transformer assembly 340 can be a DC-DC converter, which can be used to step down the high voltage obtained from the battery to a low voltage that is compatible with the self-balancing circuit 210, and output the stepped-down electrical energy to the self-balancing circuit 210 so that the self-balancing circuit 210 can perform balancing operations.

[0092] In one embodiment, the energy storage system 10 further includes a relay assembly 400 connected in series with the output terminal of the battery pack. The relay assembly 400 is used to output the electrical energy of the battery pack 100 when closed, optionally to output the battery's electrical energy to electrical appliances, such as an air conditioner. The input terminal of the equalization power extraction module 310 is connected to the path between the battery and the relay assembly 400.

[0093] In this embodiment, since the output terminals of the energy storage system 10 all supply power to the final electrical load through the relay assembly 400, in order to ensure that power is drawn from the battery to the self-balancing circuit 210 before the relay assembly 400 is turned on, the input terminal of the equalization power extraction module 310 is connected to the path between the battery and the relay assembly 400. Thus, the energy storage system 10 can still draw power from the battery to provide power support to the self-balancing circuit 210 even when the relay is not closed. In other words, technicians can activate the equalization power extraction module 310 separately for voltage equalization without starting the entire energy storage system 10 (i.e., without the relay being closed). For example, when the energy storage system 10 arrives at the site after long-term storage or transportation, technicians can manually or remotely trigger the switch module 320 to close, immediately activating the equalization power extraction module 310 to perform pre-voltage equalization and ensure the consistency of battery status. In this way, the energy storage system 10 can complete battery voltage equalization more efficiently before grid connection testing.

[0094] In one embodiment, as shown in Figures 3 and 5, the equalization power supply circuit 300 further includes an auxiliary power source module 500. The input terminal of the auxiliary power source module 500 is used to connect to an external auxiliary power source, and the output terminal of the auxiliary power source module 500 is connected to a load. The output terminal of the equalization power source module 310 includes a second output branch and a second output branch. The second output branch is connected to the battery management system 200 and the second output branch is connected to the load. One of the auxiliary power source module 500 and the second output branch is used as the power supply for the load.

[0095] Understandably, the balancing power supply circuit 300 incorporates an auxiliary power source module 500. The input of this module 500 is connected to an external auxiliary power source, while its output is connected to the load. Simultaneously, the output of the balancing power source module 310 is divided into two branches: a second output branch connects to the self-balancing circuit 210, ensuring power is provided for the self-balancing process; the second output branch connects directly to the load. The auxiliary power source module 500 and the second output branch together constitute a power supply for the load, either of which can serve as the load's power source. This significantly improves the power supply flexibility and reliability of the energy storage system 10. Optionally, when an external auxiliary power source is available, the auxiliary power source module 500 can directly power the load, reducing the battery's burden and extending its lifespan. In the absence of an external power source, the second output branch of the balancing power source module 310 can draw power from the battery, supporting not only the operation of the self-balancing circuit 210 but also continuing to provide power to the load, ensuring uninterrupted system functionality. This allows the energy storage system 10 to operate efficiently in various environments, providing additional safety features during emergencies or remote deployments. Furthermore, optionally, optimized power management enables intelligent selection of the most suitable power supply path based on actual needs, further improving energy efficiency and reducing operating costs. In summary, this design enhances the adaptability and stability of the energy storage system 10, providing users with a more flexible and reliable power solution.

[0096] It should be explained that this load is specifically a low-voltage load. Since the balancing power module 310 supplies power to the battery management system 200, its output is a low-voltage load. Because the auxiliary power module 500 and the balancing power module 310 are both connected to this low-voltage load, the auxiliary power module 500 also needs to be supplied with low-voltage power. Optionally, the low-voltage load can be one of the following common devices or components: a communication module, a sensor module, a monitoring module, a control panel, or a safety protection device, etc.

[0097] In one embodiment, as shown in FIG3, the output terminal of the auxiliary power supply module 500 is also connected to the self-balancing circuit 210; one of the auxiliary power supply module 500 and the self-balancing power supply module 310 is used as the power supply for the self-balancing circuit 210.

[0098] Understandably, the output of the auxiliary power source module 500 is connected not only to the load but also directly to the self-balancing circuit 210, allowing either the auxiliary power source module 500 or the self-balancing power source module 310 to serve as a power supply for the self-balancing circuit 210. This enhances the flexibility and reliability of the energy storage system 10 under different operating conditions.

[0099] Optionally, when an external auxiliary power source is available, the auxiliary power supply module 500 can directly provide stable power support to the self-balancing circuit 210, ensuring its efficient operation without relying on the battery's own energy. This reduces battery power consumption, extends battery life, and maintains the effectiveness of the self-balancing process even when battery voltage is low or uneven. When no external power source is available, the self-balancing power supply module 310 can draw power from the battery to supply power to the self-balancing circuit 210, performing voltage equalization in advance, thereby shortening the grid connection testing cycle and improving the overall system performance. Thus, by flexibly switching power sources, energy utilization efficiency can be optimized, unnecessary energy consumption reduced, and the self-balancing circuit 210 always operating at its best, enhancing the stability and response speed of the energy storage system 10.

[0100] It should be explained that because the battery management system 200 is powered by an external auxiliary power source, the self-balancing current may be too low, resulting in an excessively long self-balancing time for the battery management system 200 and extending the grid connection test time. Therefore, for the battery management system 200 powered by an external auxiliary power source, an external balancing module can be added, or some circuit design can be added to strengthen the self-balancing circuit 210, thus ensuring the normal operation of the battery voltage balancing. Specifically, before the external balancing module is connected, power can be supplied through the balancing power supply module 310. After the external balancing module is connected, either the balancing power supply module 310 or the auxiliary power supply module 500 can supply power to the battery management system 200.

[0101] In one embodiment, the equalization power supply circuit 300 further includes an output control circuit and a signal receiving circuit. The signal receiving circuit is connected to the input terminal of the output control circuit, and the output terminal of the output control circuit is respectively controlled to be connected to the auxiliary power source module 500 and the equalization power source module 310. The signal receiving circuit is used to receive a trigger signal and output the trigger signal to the output control circuit. The output control circuit is used to control one of the auxiliary power source module 500 and the equalization power source module 310 to be the power supply for the load according to the trigger signal. And / or, the output control circuit is used to control one of the auxiliary power source module 500 and the equalization power source module 310 to be the power supply for the battery management system 200 according to the trigger signal.

[0102] In this embodiment, the signal receiving circuit receives a trigger signal and outputs it to the output control circuit. The output control circuit then selectively controls one of the auxiliary power supply module 500 and the equalizing power supply module 310 to supply power to the load or the battery management system 200 based on the trigger signal. In one feasible embodiment, the signal receiving circuit can receive the trigger signal input by the user from various sources (such as mobile applications, computer software, or field control panels). After receiving the trigger signal, the output control circuit selectively controls either the auxiliary power supply module 500 or the equalizing power supply module 310 to supply power to the load based on preset logic or real-time status evaluation. If an external auxiliary power source is available, the system preferentially selects the auxiliary power supply module 500; if no external power source is available, it switches to the equalizing power supply module 310 to draw power from the battery. The system can also have an automatic switching mechanism that automatically selects the optimal power supply path as needed by detecting the external auxiliary power source and battery status; for example, when the external auxiliary power source is disconnected, it immediately switches to the equalizing power supply module 310 to ensure that the load and the battery management system 200 are not affected and continue to operate normally. Thus, through the output control circuit and signal receiving circuit, the energy storage system 10 not only achieves efficient energy management and power supply selection, but also optimizes the operating environment of the self-balancing circuit 210 in the load and battery management system 200, significantly improving overall performance and user experience.

[0103] In one embodiment, as shown in FIG3, the auxiliary power supply module 500 includes an auxiliary power switch and an auxiliary power conversion circuit connected in series; the auxiliary power switch is used to close after being triggered to control the auxiliary power supply module 500 to supply power to the load; the auxiliary power conversion circuit is used to perform power conversion on the power input from the external auxiliary power supply.

[0104] Understandably, the auxiliary power switch can be closed after being triggered by the user manually or remotely, establishing an electrical connection between the external auxiliary power supply and the load. This provides a simple and reliable manual or remote control mechanism, allowing users to flexibly choose whether to enable external auxiliary power supply according to actual needs. For example, after the energy storage system 10 arrives at the client site, if the external auxiliary power supply is available, technicians can send a trigger signal through a mobile application, computer software, or on-site control panel to activate the auxiliary power switch, enabling the auxiliary power module 500 to immediately provide power support to low-voltage loads (such as communication modules, sensors, control panels, etc.).

[0105] Optionally, as shown in Figure 5, the auxiliary power supply conversion circuit is an AC-DC converter used to convert the alternating current (AC) supplied by an external auxiliary power source into direct current (DC) suitable for low-voltage loads. The auxiliary power supply conversion circuit converts the AC power supplied by the external auxiliary power source into a stable DC power suitable for low-voltage loads, typically 12V or 24V. Through built-in high-efficiency conversion technology and multiple protection mechanisms (such as overvoltage protection, short-circuit protection, and temperature monitoring), the auxiliary power supply conversion circuit ensures the stability and adaptability of the output voltage, avoiding the risk of inefficiency or hardware damage due to voltage mismatch. Furthermore, the AC-DC converter can also have high energy efficiency characteristics, reducing energy loss and improving the overall system's energy utilization efficiency.

[0106] Optionally, as shown in Figure 5, the auxiliary power switch can be a second switch Q2.

[0107] Therefore, the auxiliary power switch closes upon user triggering to control the auxiliary power module 500 to supply power to the load; while the auxiliary power conversion circuit is responsible for performing the necessary conversion work on the power input from the external auxiliary power source. This provides a highly flexible and reliable external power management solution, significantly improving the overall performance and user experience of the energy storage system 10.

[0108] In one embodiment, as shown in FIG4, the self-balancing circuit 210 includes a detection unit 211 and a balancing unit 212, wherein the detection unit 211 is connected to the balancing unit 212; the detection unit 211 is used to detect the voltage signals of the plurality of batteries and output the voltage signals to the balancing unit 212, wherein the voltage signals are used to characterize the voltage of the plurality of batteries; the balancing unit 212 is used to perform parameter balancing on the plurality of batteries according to the voltage signals, so that the voltage difference of each battery is less than a first preset difference. Optionally, the detection unit 211 and the balancing unit 212 are both integrated into the battery management system 200 in the energy storage system 10.

[0109] Understandably, the detection unit 211 is responsible for real-time monitoring of the voltage signals of multiple batteries and transmitting them to the equalization unit 212. Optionally, the detection unit 211 may consist of a high-precision sensor and a data acquisition module, capable of continuously monitoring the key parameters of each battery. For example, a voltage sensor can measure the voltage level of each battery cell, a current sensor can monitor the charging and discharging current, and a temperature sensor is used to detect temperature changes in the battery. All these voltage signals are aggregated and digitized by the data acquisition module before being transmitted to the equalization unit 212. Subsequently, the equalization unit 212 performs precise parameter equalization adjustments on each battery based on the received voltage signals, ensuring that the voltage difference between each battery remains within a preset first threshold. Optionally, the equalization unit 212 internally includes control logic and adjustment circuitry, capable of dynamically adjusting the state of each battery cell based on the voltage signals provided by the detection unit 211. In some feasible implementations, if the voltage of a certain battery cell is higher than that of other cells, the equalization unit 212 can release the excess energy through a bypass resistor or a DC-DC converter; conversely, if the voltage of a certain battery cell is lower, the energy can be replenished through a charging circuit to ensure that the voltage difference between all battery cells remains within a first preset difference.

[0110] In one embodiment, the self-balancing circuit 210 includes a battery management system 200, and the detection unit 211 and the balancing unit 212 are both integrated into the battery management system 200. It is understood that integrating the detection unit 211 and the balancing unit 212 into the battery management system 200 achieves a high degree of hardware and software integration, making the entire system more compact and easier to manage. Since the battery management system 200 is a built-in unit of the energy storage system 10, performing balancing processing through the battery management system 200, instead of external balancing, makes the balancing process faster and more convenient. This further reduces the test cycle for grid connection testing.

[0111] In one embodiment, the energy storage system 10 further includes a controller for controlling the self-balancing circuit to perform balancing operations; optionally, the controller controls the self-balancing circuit to detect the voltage of multiple batteries after power-on; and controls the self-balancing circuit to perform balancing operations so that the voltage difference between each battery is less than a first preset difference.

[0112] In this embodiment, this application provides an energy storage system control method for the controller, that is, the controller can be used to implement the energy storage system control method.

[0113] As shown in Figure 6, the energy storage system control method may include steps S100 to S300.

[0114] In this embodiment, in step S100, in response to the conduction signal, the switch module 320 is controlled to close, so that the equalization power supply module 310 of the equalization circuit 20 is electrically connected to the battery management system 200, and power is supplied to the self-balancing circuit 210.

[0115] Understandably, step S100 involves closing the control switch module 320 in response to a conduction signal, thereby electrically connecting the equalization power supply module 310 of the equalization circuit 20 with the battery management system 200 and supplying power to the battery management system 200. Optionally, upon receiving a conduction signal (such as a trigger signal from a remote control system or field operation panel), the system immediately closes the switch module 320, or the switch module conducts upon the input of the conduction signal, establishing an electrical connection between the equalization power supply module 310 and the battery management system 200. This simplifies the operation process and ensures that the battery management system 200 can start quickly under any circumstances, significantly improving the reliability and efficiency of the system.

[0116] In this embodiment, step S200 involves controlling the self-balancing circuit 210 to detect the voltage of multiple batteries after power-on.

[0117] Understandably, step S200 involves controlling the self-balancing circuit 210 to detect the voltage of multiple batteries after power-on. Once the self-balancing circuit 210 receives a stable low-voltage power supply, its built-in detection unit 211 immediately begins to detect the voltage of each battery, providing a basis for balancing, avoiding erroneous adjustments due to inaccurate data, thereby improving the stability and reliability of the system and ensuring that each battery operates in optimal condition.

[0118] In this embodiment, step S300 involves controlling the self-balancing circuit 210 to perform balancing operations so that the voltage difference between each battery is less than a first preset difference.

[0119] Understandably, step S300 involves controlling the self-balancing circuit 210 to perform balancing operations, ensuring that the voltage difference between each battery is less than a first preset difference. Based on the voltage signal provided by the detection unit 211 in step S200, the balancing unit 212 dynamically adjusts the state of each battery cell to ensure that the voltage difference between all batteries remains within a preset first threshold (e.g., ±10V). For example, for batteries or battery packs with higher voltage, the balancing unit 212 can release excess energy through a bypass resistor; for batteries or battery packs with lower voltage, it replenishes energy through a charging circuit. This ensures the consistency and stability of the battery pack 100, extends battery life, effectively avoids voltage or charge inconsistencies caused by long-term accumulation, optimizes the performance and reliability of the energy storage system 10, and ensures that each battery operates in its optimal state.

[0120] Therefore, steps S100 to S300 not only shorten the preparation time and improve the operation efficiency, but also enable the self-balancing process to be started quickly without external auxiliary power supply, thereby pre-setting the voltage balancing action, optimizing the grid connection preparation process, and accelerating the grid connection acceptance speed.

[0121] In one embodiment, the controller can be used to determine that two batteries are batteries to be balanced when the voltage difference between any two batteries is not less than a first preset value; and control the self-balancing circuit to perform voltage balancing on the batteries to be balanced so that the voltage difference between the two batteries to be balanced is less than the first preset value.

[0122] As shown in Figure 7, for the above embodiment, the energy storage system control method may include steps S311 to S313.

[0123] In this embodiment, step S311 involves obtaining the voltage of each battery.

[0124] Understandably, the detection unit 211 in the self-balancing circuit 210 acquires the voltage of each battery detected in step S200 and transmits this data to the balancing unit 212 for processing. This provides a parameter basis for subsequent balancing operations.

[0125] In this embodiment, step S312 involves determining that the two batteries are batteries to be balanced if the voltage difference between any two batteries is not less than a first preset value.

[0126] Understandably, step S312 involves determining two batteries as batteries to be balanced if the voltage difference between any two batteries is not less than a first preset value. Specifically, after receiving the voltage signal provided by the detection unit 211, the balancing unit 212 automatically compares the voltage differences between each pair of batteries. If the voltage difference between any two batteries exceeds a preset first preset value (e.g., ±10V), the system marks this pair of batteries as batteries to be balanced. Therefore, by setting a reasonable threshold, the system can efficiently identify battery cells that need adjustment, reduce unnecessary balancing operations, improve energy utilization efficiency, and extend battery life.

[0127] In this embodiment, step S313 involves controlling the self-balancing circuit 210 to perform balancing operations on the battery to be balanced.

[0128] Understandably, step S313 involves controlling the self-balancing circuit 210 to balance the batteries to be balanced. After the batteries to be balanced are determined in step S312, the balancing unit 212 will activate the corresponding adjustment mechanism to ensure that the voltage difference between the batteries to be balanced remains within a preset first preset value. For example, for battery cells with higher voltage, the balancing unit 212 can release excess energy through a bypass resistor; for battery cells with lower voltage, it can replenish energy through a charging circuit. In this way, through precise parameter balancing adjustment, the system effectively avoids voltage or capacity inconsistencies caused by long-term accumulation, optimizing the performance and reliability of the energy storage system 10.

[0129] Optionally, the first preset value is used as a threshold. If the difference between the two voltages is greater than the first preset value, it can represent an impact on the power supply operation of the energy storage system 10.

[0130] Therefore, by going through steps S311 to S313, the batteries that need to be adjusted can be accurately located, unnecessary balancing operations can be avoided, energy utilization efficiency can be improved, and minor differences between batteries can be corrected in a timely manner.

[0131] In one embodiment, the controller is specifically configured to determine the average voltage of each battery as a first preset reference value; if the difference between the voltage of the battery and the first preset reference value is not less than a second preset value, determine the battery as a battery to be balanced; and control the self-balancing circuit to perform voltage balancing on the battery to be balanced, so that the difference between the voltage of the battery to be balanced and the first preset reference value is less than the second preset value.

[0132] As shown in Figure 8, for the above embodiment, the energy storage system control method may include steps S321 to S323.

[0133] In this embodiment, step S321 involves obtaining the voltage of each battery and determining the average voltage of each battery as a first preset reference value.

[0134] Understandably, step S321 involves acquiring the voltage of each battery and calculating the average value of these parameters as a first preset reference value. Optionally, the detection unit 211 in the self-balancing circuit 210 monitors the key voltage of each battery in real time and transmits this data to the balancing unit 212 for processing. After summarizing the voltages of all batteries, the balancing unit 212 calculates the average value of these parameters and determines it as the first preset reference value. For example, if there are 10 batteries in the system, the balancing unit 212 will calculate the average voltage of these 10 batteries as a benchmark for subsequent comparisons. In this way, by calculating the average value of all battery parameters as a reference point, the system provides a unified standard, ensuring that the balancing adjustment is based on the overall state, avoiding misjudgments caused by individual battery anomalies, and improving the stability and reliability of the system.

[0135] In this embodiment, step S322, if the difference between the battery voltage and the first preset reference value is not less than the second preset value, the battery is determined to be a battery to be balanced.

[0136] Understandably, step S322 involves determining a battery as a battery to be balanced if the difference between its voltage and a first preset reference value is not less than a second preset value. Optionally, after receiving the voltage signal provided by the detection unit 211, the balancing unit 212 compares the voltage of each battery with its first preset reference value. If the difference between the voltage of a battery and the reference value exceeds a preset second preset value (e.g., ±10V), the system marks that battery as a battery to be balanced. This ensures that only batteries significantly different from the overall state are selected for balancing, avoiding unnecessary energy consumption and operational complexity.

[0137] In this embodiment, step S323 involves activating the balancing mode for the battery to be balanced, so that the difference between the voltage of the battery to be balanced and the first preset reference value is less than the second preset value.

[0138] Understandably, step S323 involves activating a balancing mode for the batteries to be balanced, ensuring that the difference between the voltage of the battery to be balanced and the first preset reference value is less than a second preset value. Once the batteries to be balanced are identified, the balancing unit 212 activates a corresponding adjustment mechanism to ensure that the difference between the voltage of these batteries and the first preset reference value remains within a preset second preset value. For example, for battery cells with higher voltage, the balancing unit 212 can release excess energy through a bypass resistor; for battery cells with lower voltage, energy is replenished through a charging circuit. In this way, through precise parameter balancing adjustment based on average values, the system effectively avoids voltage or capacity inconsistencies caused by long-term accumulation, significantly optimizing the performance and reliability of the energy storage system 10.

[0139] Optionally, the second preset value is used as a threshold. If the difference between the battery voltage and the average voltage is greater than the second preset value, it can represent an impact on the power supply operation of the energy storage system 10.

[0140] In one embodiment, the equalization power supply circuit 300 includes an equalization power extraction module 310 and an auxiliary power extraction module 500. The input terminal of the equalization power extraction module 310 is connected to the battery of the energy storage system 10, and the input terminal of the auxiliary power extraction module 500 is connected to an external auxiliary power source. The output terminals of the equalization power extraction module 310 and the auxiliary power extraction module 500 are respectively connected to the load. As shown in FIG9, the energy storage system control method further includes steps S410 to S440.

[0141] In this embodiment, step S410 involves acquiring the operating voltage of the load and the output voltages of the balancing power supply module 310 and the auxiliary power supply module 500. It is understood that step S410 involves acquiring the operating voltage of the load and the output voltages of the balancing power supply module 310 and the auxiliary power supply module 500. Optionally, the system detects the current operating voltage of the load and simultaneously detects the output voltages of the balancing power supply module 310 and the auxiliary power supply module 500. This series of data is aggregated by the built-in sensors and data acquisition module and then transmitted to the control system for processing.

[0142] In this embodiment, step S420 involves determining a first difference between the operating voltage and the output voltage of the equalizing power supply module 310, and a second difference between the operating voltage and the output voltage of the auxiliary power supply module 500. It is understood that after receiving the voltage data, the control system calculates two differences: the first difference between the load operating voltage and the output voltage of the equalizing power supply module 310, and the second difference between the load operating voltage and the output voltage of the auxiliary power supply module 500. This ensures that the power source closest to the load requirements is selected subsequently. In this way, the system can intelligently select the optimal power supply path, reduce unnecessary energy loss, and improve the stability and reliability of the power supply.

[0143] In this embodiment, step S430 involves outputting a first power supply signal in response to the first difference being greater than the second difference, and controlling the auxiliary power supply module 500 to supply power to the load.

[0144] In this embodiment, in step S440, in response to the first difference not being greater than the second difference, a second power supply signal is output, and the equalization power supply module 310 is controlled to supply power to the load.

[0145] Understandably, step S430 involves responding to a first power supply signal output when the first difference is greater than the second difference, i.e., the output voltage of the auxiliary power supply module 500 is closer to the load's requirements. The control system will then send a command to close the switch of the auxiliary power supply module 500, allowing the auxiliary power supply module 500 to supply power to the load. Step S440 involves responding to a second power supply signal output when the first difference is not greater than the second difference, controlling the equalization power supply module 310 to supply power to the load. That is, when the output voltage of the equalization power supply module 310 is closer to the load's requirements, the control system will send a command to close the switch of the equalization power supply module 310, allowing the equalization power supply module 310 to supply power to the load.

[0146] In one embodiment, the equalization power supply circuit 300 includes an equalization power extraction module 310 and an auxiliary power extraction module 500. The input terminal of the equalization power extraction module 310 is connected to the battery of the energy storage system 10, the input terminal of the auxiliary power extraction module 500 is connected to an external auxiliary power source, and the output terminals of the equalization power extraction module 310 and the auxiliary power extraction module 500 are respectively connected to the self-balancing circuit 210.

[0147] As shown in Figure 10, the energy storage system control method further includes steps S510 to S540.

[0148] In this embodiment, step S510 involves obtaining the operating voltage of the self-balancing circuit 210 and the output voltages of the equalization power supply module 310 and the auxiliary power supply module 500.

[0149] In this embodiment, step S520 involves determining a first difference between the operating voltage and the output voltage of the equalization power supply module 310, and determining a second difference between the operating voltage and the output voltage of the auxiliary power supply module 500.

[0150] In this embodiment, in step S530, in response to the first power supply signal being output when the first difference is greater than the second difference, the auxiliary power supply module 500 is controlled to supply power to the self-balancing circuit 210.

[0151] In this embodiment, in step S540, in response to the first difference not being greater than the second difference, the second power supply signal is output, and the equalization power supply module 310 is controlled to supply power to the self-equalization circuit 210.

[0152] It is understood that step S530 involves responding to a first power supply signal output when the first difference is greater than the second difference, controlling the auxiliary power supply module 500 to supply power to the self-balancing circuit 210. That is, when the output voltage of the auxiliary power supply module 500 is closer to the requirements of the self-balancing circuit 210, the control system will send a command to close the switch of the auxiliary power supply module 500, enabling the auxiliary power supply module 500 to supply power to the self-balancing circuit 210. Step S540 involves responding to a second power supply signal output when the first difference is not greater than the second difference, controlling the equalization power supply module 310 to supply power to the self-balancing circuit 210. That is, when the output voltage of the equalization power supply module 310 is closer to the requirements of the self-balancing circuit 210, the control system will send a command to close the switch of the equalization power supply module 310, enabling the equalization power supply module 310 to supply power to the self-balancing circuit 210. In this way, when the external auxiliary power supply is unavailable, the system can quickly switch to battery power, pre-emptively performing voltage balancing, shortening the grid connection testing cycle, accelerating grid connection acceptance, and improving the overall progress and efficiency of the project.

[0153] In one embodiment, as shown in FIG11, the energy storage system control method further includes a pre-balancing strategy, namely steps S610 to S640.

[0154] In this embodiment, in step S610, after the switch module 320 is turned on, the battery management system 200 is controlled to perform voltage detection and SOC status detection on the multiple batteries.

[0155] Understandably, when the switch module 320 is closed, the battery management system 200 is powered on and ready to enter the working state. At this time, the battery management system 200 will initiate a series of detection operations. First, it monitors the voltage of each battery cell in real time and records the current voltage value of each battery cell to ensure that the latest voltage data is obtained. At the same time, the battery management system 200 will also detect the state of charge (SOC) of each battery cell to determine the charging level of each battery cell. In this way, accurate data support is provided for subsequent balancing decisions, thereby ensuring the stability and reliability of the system.

[0156] In this embodiment, step S620 involves determining that the multiple batteries meet the first equalization start-up condition when the maximum voltage difference between the multiple batteries is greater than a first preset value.

[0157] Understandably, the battery management system 200 calculates the maximum voltage difference between the batteries and compares this difference with a preset first value. If the maximum voltage difference exceeds the first preset value, it is considered that there is a significant voltage inconsistency in the battery pack, requiring equalization adjustment. The specific value of the first preset value is not limited here; it is used to provide reference data for the system to effectively identify which batteries need adjustment, avoiding unnecessary energy consumption and operational complexity.

[0158] In this embodiment, step S630 involves determining that the multiple batteries meet the second equalization start-up condition when the SOC state of the multiple batteries and the minimum voltage of the multiple batteries meet preset conditions.

[0159] Understandably, the battery management system 200 may optionally check the SOC of each battery cell, and preset conditions may be set to ensure that the SOC of all battery cells is not lower than a first preset SOC (e.g., 80%). Simultaneously, the system will also check the voltage of the battery cell with the lowest voltage in the battery pack, ensuring that it is not lower than a third preset value. These two conditions together form the aforementioned preset conditions, and only after these preset conditions are met will multiple batteries be deemed to have met the second equalization start-up condition. By setting reasonable first and third preset SOC values, the equalization process can be ensured to start under safe conditions, avoiding battery damage or other safety hazards caused by excessively low SOC or minimum voltage, thereby improving the safety and reliability of the system and ensuring that each battery operates in its optimal state.

[0160] In this embodiment, step S640 involves controlling the battery management system 200 to perform balancing operations when multiple batteries meet the first and second balancing start conditions; and controlling the battery management system 200 to go into standby mode when multiple batteries do not meet the first and second balancing start conditions.

[0161] Understandably, if the battery meets both the first and second equalization start-up conditions, the battery management system 200 will initiate equalization operations to ensure that the operating parameters of each battery cell remain consistent. If the battery does not meet either of the above conditions, the battery management system 200 will enter a standby state, awaiting further operational instructions or changes in conditions.

[0162] It should be noted that the above balancing is performed on a battery-by-battery basis. In some scenarios, the energy storage system includes multiple battery packs 100, and each battery pack 100 includes multiple batteries. In this case, balancing can also be performed on a battery pack-by-battery basis.

[0163] Secondly, this application also provides a battery management system 200 applied to an energy storage system 10, the energy storage system 10 including a battery pack 100, the battery pack 100 including multiple batteries; the battery management system 200 includes: a battery management circuit, a self-balancing circuit 210 and a voltage equalization power supply circuit 300, the battery management circuit being used to manage the battery pack 100, the self-balancing circuit 210 being used to equalize the voltage of the multiple batteries; the input terminal of the voltage equalization power supply circuit 300 is electrically connected to the battery pack 100, the voltage equalization power supply circuit 300 being used to draw power from the battery pack 100, and convert the electrical energy obtained from the battery pack 100 into power supply energy and output it to the battery management system 200, so as to control the self-balancing circuit 210 to equalize the voltage of the multiple batteries.

[0164] It should be noted that the battery management system 200 is a commonly used battery management system (BMS) in energy storage systems, which includes battery management circuitry for routine battery management. Therefore, in addition to the battery management circuitry, this battery management system 200 also includes a self-balancing circuit 210 and a power supply balancing circuit 300.

[0165] Understandably, the self-balancing circuit 210 is used to perform battery voltage balancing for multiple batteries. This battery management system 200 can draw power from multiple batteries in the battery pack 100 and convert that power into power compatible with the self-balancing circuit 210, allowing the self-balancing circuit 210 to directly begin balancing operations. However, in some exemplary technologies, an external auxiliary power source is manually connected and external balancing is performed before grid connection testing, resulting in a lengthy grid connection testing cycle for the energy storage system 10. The battery management system 200 of this application, located after the energy storage system 10, allows the balancing action, which originally needed to be performed after connecting the external auxiliary power source in exemplary technologies, to be performed during the external auxiliary power source preparation stage. This separates the balancing process from the grid connection testing, effectively shortening the entire grid connection testing cycle.

[0166] Optionally, the equalization power supply circuit 300 can supply power to the self-balancing circuit 210 and the battery management circuit at the same time.

[0167] In one embodiment, the equalization power supply circuit 300 includes an equalization power extraction module 310 and a switch module 320. The input terminal of the equalization power extraction module 310 is connected to the battery pack 100. The equalization power extraction module 310 is used to extract power from the battery pack 100 and convert the electrical energy obtained from the battery pack 100 into power supply energy for output. The switch module 320 is connected in series between the equalization power extraction module 310 and the power supply terminal of the battery management system 200. The switch module 320 is used to close when triggered to control the electrical connection between the equalization power extraction module 310 and the battery management system 200 and to supply power to the battery management system 200.

[0168] The power supply terminal of the battery management system 200 can be used to power the battery management circuit or the self-balancing circuit 210. When the power supply terminal powers the self-balancing circuit 210, it can achieve voltage balancing of the front battery to reduce the grid connection test cycle.

[0169] It is understood that the balancing power extraction module 310 in this balancing power supply circuit 300 has its input end connected to the multiple batteries, and its output end connected to the self-balancing circuit 210 through the switch module 320. Thus, when the energy storage product arrives at the customer's location, the operator can manually close the power extraction switch in the switch module 320, and the balancing power extraction module 310 will then draw high-voltage electricity from the batteries as the power supply for the self-balancing circuit 210. In other words, the balancing action, which originally needed to be performed concurrently with grid connection testing after the external auxiliary power supply was connected, can now be carried out during the external auxiliary power supply preparation stage, thereby separating the balancing process from the grid connection test and effectively shortening the entire grid connection test cycle.

[0170] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not 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 or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. An energy storage system, wherein, The energy storage system includes: A battery pack, comprising multiple batteries; A battery management system, including a self-balancing circuit for voltage equalization of a plurality of said batteries; The equalization power supply circuit has its input terminal electrically connected to the battery pack. The equalization power supply circuit is used to draw power from the battery pack and convert the electrical energy obtained from the battery pack into power supply energy and output it to the battery management system to control the self-balancing circuit to equalize the voltage of multiple batteries.

2. The energy storage system as described in claim 1, wherein, The equalization power supply circuit includes: A balanced power extraction module, the input terminal of which is connected to the battery pack, is used to extract power from the battery pack and convert the electrical energy obtained from the battery pack into power supply energy for output. A switch module is connected in series between the equalization power supply module and the power supply terminal of the battery management system. The switch module is used to close when triggered to control the electrical connection between the equalization power supply module and the battery management system and to supply power to the battery management system.

3. The energy storage system as described in claim 2, wherein, The switching module includes a mechanical switch that is closed when triggered to control the electrical connection between the power supply module and the battery management system, and to supply power to the battery management system.

4. The energy storage system as described in claim 2, wherein, The switch module includes an electronically controlled switch and a communication component, wherein the electronically controlled switch and the communication component are connected. The communication component is used to receive a trigger signal. The electronic control switch closes in response to the trigger signal to control the electrical connection between the power supply module and the battery management system and to supply power to the battery management system.

5. The energy storage system as described in claim 2, wherein, The equalization power supply module includes a transformer assembly, which is connected in series between the battery and the switch module, or the transformer assembly is connected in series with the end of the switch module away from the battery. The transformer assembly is used to step down the output voltage of the battery so that the output voltage of the battery is adapted to the operating voltage of the self-balancing circuit of the battery management system.

6. The energy storage system as described in claim 2, wherein, The energy storage system also includes a relay assembly connected in series with the output terminal of the battery pack, and the relay assembly is used to output the electrical energy of the battery pack when closed; The input terminal of the equalization power supply module is connected to the path between the battery and the relay assembly.

7. The energy storage system according to any one of claims 2 to 6, wherein, The balanced power supply circuit also includes an auxiliary power source module, the input of which is used to connect to an external auxiliary power source, and the output of which is connected to the load. The output terminal of the equalization power supply module includes a first output branch and a second output branch. The first output branch is connected to the battery management system, and the second output branch is connected to the load. One of the auxiliary power supply module and the second output branch is used as the power supply for the load.

8. The energy storage system as described in claim 7, wherein, The output terminal of the auxiliary power supply module is also connected to the battery management system. One of the auxiliary power supply module and the equalization power supply module is used as the power supply for the battery management system.

9. The energy storage system as described in claim 8, wherein, The equalization power supply circuit also includes an output control circuit and a signal receiving circuit. The signal receiving circuit is connected to the input terminal of the output control circuit, and the output terminal of the output control circuit is respectively connected to the auxiliary power source module and the equalization power source module. A signal receiving circuit is used to receive a trigger signal and output the trigger signal to the output control circuit. The output control circuit is used to control one of the auxiliary power supply module and the equalization power supply module to be the power supply for the load according to the trigger signal. And / or, The output control circuit is used to control one of the auxiliary power supply module and the equalization power supply module to provide power to the battery management system according to the trigger signal.

10. The energy storage system as claimed in claim 7, wherein, The auxiliary power supply module includes an auxiliary power switch and an auxiliary power conversion circuit connected in series. The auxiliary power switch is used to close when triggered, so as to control the auxiliary power supply module to supply power to the load; The auxiliary power conversion circuit is used to perform power conversion on the power input from the external auxiliary power source.

11. The energy storage system as claimed in claim 1, wherein, The self-balancing circuit includes a detection unit and an equalization unit, wherein the detection unit is connected to the equalization unit. The detection unit is used to detect the voltage signals of the multiple battery packs and output the voltage signals to the equalization unit; The equalization unit is used to perform voltage equalization on the plurality of battery packs according to the voltage signal, so that the voltage difference of each battery pack is less than a first preset difference.

12. The energy storage system as claimed in claim 1, wherein, The energy storage system also includes a controller, which is used to control the self-balancing circuit to detect the voltage of multiple batteries after power-on, and to control the self-balancing circuit to perform balancing work so that the voltage difference between each battery is less than a first preset difference.

13. The energy storage system of claim 12, wherein, The controller is used to determine that the two batteries are batteries to be balanced if the voltage difference between any two batteries is not less than a first preset value. The self-balancing circuit is controlled to perform voltage balancing on the batteries to be balanced, so that the voltage difference between the two batteries to be balanced is less than a first preset value.

14. The energy storage system of claim 12, wherein, The controller is used to determine the average voltage of each battery as a first preset reference value; and to determine the battery as a battery to be balanced if the difference between the voltage of the battery and the first preset reference value is not less than a second preset value. The self-balancing circuit is controlled to perform voltage balancing on the battery to be balanced, so that the difference between the voltage of the battery to be balanced and the first preset reference value is less than the second preset value.

15. A control method for an energy storage system, wherein, The energy storage system is the energy storage system according to claim 1, and the energy storage system control method includes: The self-balancing circuit is controlled to detect the voltage of multiple batteries after power-on; The self-balancing circuit is controlled to perform balancing operations so that the voltage difference between each battery is less than a first preset difference.

16. The energy storage system control method as described in claim 15, wherein, The equalization power supply circuit includes an equalization power extraction module and an auxiliary power extraction module. The input terminal of the equalization power extraction module is connected to the battery of the energy storage system, the input terminal of the auxiliary power extraction module is connected to an external auxiliary power source, and the output terminals of the equalization power extraction module and the auxiliary power extraction module are respectively connected to the load. The energy storage system control method further includes: Obtain the operating voltage of the load, and obtain the output voltages of the equalization power supply module and the auxiliary power supply module; Determine a first difference between the operating voltage and the output voltage of the equalization power supply module, and determine a second difference between the operating voltage and the output voltage of the auxiliary power supply module; In response to the first power supply signal being output when the first difference is greater than the second difference, the auxiliary power supply module is controlled to supply power to the load; In response to a second power supply signal output when the first difference is not greater than the second difference, the equalization power supply module is controlled to supply power to the load.

17. The energy storage system control method as described in claim 15, wherein, The equalization power supply circuit includes an equalization power extraction module and an auxiliary power extraction module. The input terminal of the equalization power extraction module is connected to the battery of the energy storage system, the input terminal of the auxiliary power extraction module is connected to an external auxiliary power source, and the output terminals of the equalization power extraction module and the auxiliary power extraction module are respectively connected to the self-balancing circuit. The energy storage system control method further includes: Obtain the operating voltage of the self-balancing circuit, and obtain the output voltages of the balancing power supply module and the auxiliary power supply module; Determine a first difference between the operating voltage and the output voltage of the equalization power supply module, and determine a second difference between the operating voltage and the output voltage of the auxiliary power supply module; In response to the first power supply signal being output when the first difference is greater than the second difference, the auxiliary power supply module is controlled to supply power to the self-balancing circuit; In response to a second power supply signal output when the first difference is not greater than the second difference, the equalization power supply module is controlled to supply power to the self-balancing circuit.

18. The energy storage system control method as described in claim 15, wherein, The step of controlling the self-balancing circuit to perform balancing operations so that the voltage difference between each battery is less than a first preset difference includes: Obtain the voltage of each of the aforementioned batteries; If the voltage difference between any two batteries is not less than a first preset value, the two batteries are determined to be batteries to be balanced. The self-balancing circuit is controlled to balance the battery to be balanced.

19. A battery management system, wherein, The battery management system is applied to an energy storage system, the energy storage system including a battery pack, the battery pack including multiple batteries; the battery management system includes: A battery management circuit, which is used for battery management of the battery pack; A self-balancing circuit is used to balance the voltage of the multiple batteries. The equalization power supply circuit has its input terminal electrically connected to the battery pack. The equalization power supply circuit is used to draw power from the battery pack and convert the electrical energy obtained from the battery pack into power supply energy and output it to the battery management system to control the self-balancing circuit to equalize the voltage of multiple batteries.

20. The battery management system of claim 19, wherein, The equalization power supply circuit includes: A balanced power extraction module, the input terminal of which is connected to the battery pack, is used to extract power from the battery pack and convert the electrical energy obtained from the battery pack into power supply energy for output. A switch module is connected in series between the equalization power supply module and the power supply terminal of the battery management system. The switch module is used to close when triggered to control the electrical connection between the equalization power supply module and the battery management system and to supply power to the battery management system.

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